US010727540B2

United States Patent ( 10 ) Patent No.: US 10,727,540 B2

Takami et al. (45 ) Date of Patent: Jul. 28 , 2020
( 54 ) SECONDARY BATTERY, BATTERY (58 ) Field of Classification Search
MODULE , BATTERY PACK AND VEHICLE CPC .. HO1M 10/38 ; HO1M 4/485 ; HO1M 2220/20 ;
HO1M 4/5825 ; HO1M 2300/002
(71) Applicant: KABUSHIKI KAISHA TOSHIBA , See application file for complete search history .
Minato -ku ( JP )
(72 ) Inventors: Norio Takami, Yokohama (JP ) ; (56 ) References Cited
Yasunobu Yamashita , Tokyo ( JP ) ;
Shinsuke Matsuno , Tokyo ( JP ) ; U.S. PATENT DOCUMENTS
Yasuhiro Harada , Isehara ( JP ); Hiroki 6,403,253 B1 6/2002 Wainwright et al.
Inagaki, Yokohama (JP ) 9,184,470 B2 11/2015 Kwon et al.
(73) Assignee : KABUSHIKI KAISHA TOSHIBA , (Continued )
Minato -ku (JP ) FOREIGN PATENT DOCUMENTS
( * ) Notice : Subject to any disclaimer, the term of this CN 101154745 A 4/2008
patent is extended or adjusted under 35 JP WO 95/21470 A1 8/1995
U.S.C. 154(b ) by 0 days. (Continued )
(21) Appl. No.: 15 57,406 OTHER PUBLICATIONS
(22) Filed : Mar. 13, 2017 International Search Report dated Mar. 14 , 2017 in PCT/ JP2017/
(65) Prior Publication Data 003666 ( submitting English language translation only ).
(Continued )
US 2017/0222272 A1 Aug. 3 , 2017
Related U.S. Application Data Primary Examiner Cynthia H Kelly
(63) Continuation of application No. Assistant Examiner - Monique M Wills
PCT/ JP2017 /003666 , filed on Feb. 1 , 2017 . (74 ) Attorney, Agent, or Firm — Oblon, McClelland,
Maier & Neustadt, L.L.P.
( 30 ) Foreign Application Priority Data
Feb. 1 , 2016 ( JP ) 2016-017249 (57) ABSTRACT
Sep. 21, 2016 ( JP ) 2016-184794
According to one embodiment, a secondary battery includ
(51) Int. Ci. ing a positive electrode , a negative electrode , and an elec
HOIM 4700 (2006.01) trolyte is provided . The negative electrode includes tita
HOIM 10/38 ( 2006.01) nium -containing oxide and at least one kind of element
(Continued ) selected from the group consisting of B , P , A1, La, Zr, Ge,
(52) U.S. CI. Zn , Sn , Ga, Pb , In , Bi, and Tl. The electrolyte includes
CPC HOIM 10/38 ( 2013.01) ; HOTM 2/1077 lithium ions and a solvent containing water.
(2013.01 ); HOIM 4/485 (2013.01 );
(Continued ) 34 Claims, 12 Drawing Sheets
8 9
10 11 1 11

6
7

5
-2
 US 10,727,540 B2
Page 2

(51) Int. Ci. JP

JP
2007-123093 A
2009-110931 A
5/2007
HOIM 4/485 (2010.01) 5/2009
HOIM 2/10 JP 4301527 B2 7/2009
( 2006.01 ) JP 2009-259473 11/2009
HOIM 4/58 ( 2010.01 ) JP 2010-108676 A 5/2010
HOIM 4/02 (2006.01) JP 2011-249238 A 12/2011
JP 2012-123952 6/2012
(52) U.S. CI. JP 2012-248436 A 12/2012
CPC HOTM 4/5825 ( 2013.01); HOIM 2004/027 JP 2013-101908 5/2013
(2013.01 ); HOLM 2220/20 (2013.01); HOLM JP
JP
5300502
2015-502013
9/2013
2300/002 (2013.01 ) JP 2015-46307 A
1/2015
3/2015
( 56 ) References Cited JP 2015-156356 8/2015
KR 10-2006-0117247 A 11/2006
U.S. PATENT DOCUMENTS KR 10-2009-0108708 A 10/2009
KR 10-2010-0106196 A 10/2010
KR 10-2015-0047274 A 5/2015
2006/0204839 A1 * 9/2006 Richards HO1M 2/0257 WO WO 2008/001541 1/2008
429/137 WO WO 2008/088832 A2 7/2008
2009/0087742 A1 4/2009 Martinet et al. WO WO 2009/008280 1/2009
2010/0136427 Al 6/2010 Kondo et al. WO WO 2009/008280 Al 1/2009
2010/0238606 A1 9/2010 Dreissig et al. WO WO 2010/090224 A1 8/2010
2010/0255352 Al 10/2010 Inagaki et al.
2011/0200848 A1 * 8/2011 Chiang BOOL 11/1875
429/4 OTHER PUBLICATIONS
2012/0077074 A1 * 3/2012 Hoshina CO1G 23/005
429/149 International Search Report and Written Opinion dated Mar. 14 ,
2013/0095386 Al 4/2013 Xu et al . 2017 in PCT/JP2017 /003666 (with English Translation of Catego
2013/0115513 Al 5/2013 Choi et al . ries of Cited Documents ).
2013/0330629 A1* 12/2013 Matsuno HOIM 4/131 S. Liu , et al., “ Rechargeable Aqueous Lithium -Ion Battery of
429 /231.1 TiOz/LiMn204 with a High Voltage ” Journal of the Electrochemical
2015/0079467 A1 * 3/2015 Ahn HO1M 4/131 Society, vol. 156 , No. 12, 2011, pp . A1490 -A1497.
2015/0147646 A1 * 5/2015 McGee
429/215
HO1M 4/622
Mao - Sung . Wu, et al., "Electrochemical fabrication of anatase TiO2
429/217
nanostructure as an anode material for aqueous lithium -ion batter
2015/0318530 A1 11/2015 Yushin et al .
ies” Journal of Power Sources , vol. 185 , 2008 , pp . 1420-1424 .
2016/0308220 A1 * 10/2016 Qi HO1M 4/90
Safety Data Sheet for Lithium Hexafluorophosphate ; retrieved from
2017/0098823 A1 * 4/2017 Yushin HO1M 4/364
" https://www.ltschem.com/msds/LiPF6.pdf” , accessed 10:40 AM
Japan time on Feb. 5, 2019 .
FOREIGN PATENT DOCUMENTS Wang, G.X., et al., "Secondary aqueous lithium -ion batteries with
spinel anodes and cathodes” , Journal of Power Sources, vol. 74 ,
JP H 9-508490 8/1997 1998 , pp . 198-201 .
JP 2000-077073 3/2000 Robab Khayat Ghavamiet al., Effects of cationic CTAB and anionic
JP 2002-42764 A 2/2002 SDBS surfactants on the performance of Zn - MnO2 alkaline bat
JP 2002-110221 A 4/2002 teries, Journal of Power Sources 164 ( 2007 ) 934-946 .
JP 2003-017057 1/2003 Haegyeom Kim et al., “ Aqueous Rechargeable Li and Na Ion
JP 2005-071807 3/2005 Batteries” Chem . Rev. 2014 ; 114 , pp . 11788-11827 .
JP 2006-100244 4/2006
JP 2006-127848 A 5/2006 * cited by examiner
U.S. Patent Jul. 28 , 2020
9 Sheet 1 of 12 US 10,727,540 B2

8 9
11 1 11
10 4
6
-7

5
-2

FIG . 1
U.S. Patent Jul. 28 , 2020
9 Sheet 2 of 12 US 10,727,540 B2

11
6 nN

-2 .

FIG . 2
U.S. Patent Jul. 28 , 2020
9 Sheet 3 of 12 US 10,727,540 B2

13
12
A

FIG . 3

3
4a
4
3
4a
4
3
4a
4
3b
33 ??
3b
4b 4a 12
4a 5
4 4b

FIG . 4
U.S. Patent Jul. 28 , 2020
9 Sheet 4 of 12 US 10,727,540 B2

31
+
33 8 9
8
9

325 324 323 322 321

FIG . 5
U.S. Patent Jul. 28 , 2020
9 Sheet 5 of 12 US 10,727,540 B2

40
45 46
41 44
-431
-432 42
433
-434
-435

44

FIG . 6
U.S. Patent Jul. 28 , 2020
9 Sheet 6 of 12 US 10,727,540 B2

-70

55
54
68
68

52 51
62 53
56 68
63
# 58 67
53
67 60

61
59

69

FIG . 7
U.S. Patent Jul. 28 , 2020
9 Sheet 7 of 12 US 10,727,540 B2

61 60
+
-51
64
58 +

66a
51
59
+

67 51
Protective
circuit
+
51
66b
1

65
Thermistor + 51

57 63 62

FIG . 8
U.S. Patent Jul. 28 , 2020
9 Sheet 8 of 12 US 10,727,540 B2

101 103 104

108

102 105 106 107

FIG . 9

117 116
119 122 113 118
121 110
115 ? 114

111 -

112
-120

FIG . 10
U.S. Patent Jul. 28 , 2020
9 Sheet 9 of 12 US 10,727,540 B2

118 116
114
-120

113

FIG . 11
U.S. Patent Jul. 28 , 2020
9 Sheet 10 of 12 US 10,727,540 B2

131
+
133 116 117
116
117

1325 1324 1323 1322 1321

FIG . 12
U.S. Patent Jul. 28 , 2020
9 Sheet 11 of 12 US 10,727,540 B2

141

142

FIG . 13
U.S. Patent Jul. 28 , 2020 Sheet 12 of 12 US 10,727,540 B2

370 L1
-

380
Exptoerwnealrtcoenrmictaoln Voltagetempratumeonitrng Bat erymodule
)
VTM
(

Ecloentroicl )
ECU
unit
(
11 IT
317
314a
312a
314
312b
313a
Bat ermyange t Voltage
)
BMU
(
unit +Bat erymodule FIG
14
.
311

301
temprautemonitrng
3313c13b
VTM
(
)

module
310 +
Bat ery 31631203140
L2
333
340 331
A

300

345 W
 US 10,727,540 B2
1 2
SECONDARY BATTERY, BATTERY stability of the nonaqueous electrolyte is poor, high -tem
MODULE , BATTERY PACK AND VEHICLE perature cycle life performance is lowered. Also , although a
solid electrolyte has been considered as a nonaqueous elec
CROSS -REFERENCE TO RELATED trolyte , since the ion conductivity of the nonaqueous elec
APPLICATIONS 5
trolyte is further lowered , it is difficult to enhance large
current discharge performance .
This application is a Continuation application of PCT In a nonaqueous electrolyte battery charged and dis
Application No. PCT/ JP2017 /003666 , filed Feb. 1, 2017 , charged by movement of Li ions between a negative elec
and based upon and claiming the benefit of priority from trode and a positive electrode, a nonaqueous electrolyte
Japanese Patent Application No. 2016-017249 , filed Feb. 1, 10 containing a nonaqueous solvent is used as an electrolytic
2016 , and Japanese Patent Application No. 2016-184794 , solution . Since the nonaqueous solvent has wide potential
filed Sep. 21 , 2016 , the entire contents of all of which are stability, in the nonaqueous electrolyte battery, a high cell
incorporated herein by reference . voltage of approximately 3 to 4 V can be exhibited. Thus, the
FIELD
nonaqueous electrolyte battery is excellent in energy density
15 as compared with conventional storage batteries. Therefore,
in recent years, the use of nonaqueous electrolyte batteries
Embodiments of the present invention relate to a second has been progressing in a wide range of applications includ
ary battery, a battery module , a battery pack and a vehicle . ing on -vehicle application such as uHEV (micro -hybrid
electric vehicle ) and an idling stop system , and for stationary
BACKGROUND 20 use .

A nonaqueous electrolyte battery in which a lithium However, since a nonaqueous solvent contained in a
nonaqueous electrolyte is an organic solvent, the nonaque
metal, a lithium alloy , a lithium compound or a carbona ous solvent is highly volatile and inflammable . Thus, a
ceous material is used for a negative electrode is expected as nonaqueous electrolyte battery has risks such as a possibility
a high energy density battery, and active research and 25 of ignition associated with over-charge, temperature
development have been conducted . A lithium ion secondary increase, or impact . To prevent such risks , the use of an
battery including a positive electrode containing LiCoO2 or aqueous solvent in a lithium ion battery has been proposed.
LiMn204 as an active material and a negative electrode
containing a carbonaceous material that allows lithium ions BRIEF DESCRIPTION OF THE DRAWINGS
to be inserted in and extracted from has been widely put to 30
practical use for a portable device . FIG . 1 is a partially cutout cross -sectional view of a
In the case of installing the battery in a vehicle such as an secondary battery of an embodiment;
automobile or a train , it is desirable that the positive and FIG . 2 is side view of the battery of FIG . 1 ;
negative electrodes include a material excellent in chemical FIG . 3 is a partially cutout perspective view of the
and electrochemical stability , in durability, and in corrosion 35 secondary battery of the embodiment;
resistance for obtaining a storage performance in high FIG . 4 is an enlarged cross- sectional view of an A portion
temperature environments (e.g., at not less than 60 ° C.), of FIG . 3 ;
cycle performance, and reliability of high power over a long FIG . 5 is a perspective view of an example of a battery
time. Further, high performance in cold climates , high module of the embodiment;
output performance in a low -temperature environment (-40 ° 40 FIG . 6 is a perspective view of an example of a battery
C.), and long life performance are required . On the other pack of the embodiment;
hand, although a nonvolatile and noncombustible electro FIG . 7 is an exploded perspective view of another
lytic solution has been developed as a nonaqueous electro example of a battery pack of the embodiment;
lyte for enhancing safety performance, a battery including FIG . 8 is a block diagram showing an electric circuit of
the electrolytic solution has not yet been put to practical use 45 the battery pack of FIG . 7 ;
because output characteristics , low - temperature perfor FIG . 9 is a schematic cross -sectional view of an example
mance , and long life performance are reduced . of a coin - type secondary battery according to an embodi
As described above , when the lithium ion secondary ment;
battery is installed in a vehicle or the like , there is a problem FIG . 10 is a schematic cross -sectional view of an example
with the high- temperature durability and low - temperature 50 of a square- type secondary battery according to an embodi
output performance . Thus, it is difficult to install the lithium ment;
ion secondary battery in an engine room of the vehicle in FIG . 11 is a schematic cross - sectional view of a side
place of a lead storage battery. surface of the square- type secondary battery in FIG . 10 ;
Since an electrolytic solution of the lithium ion secondary FIG . 12 is a perspective view of an example of a battery
battery is used at a high voltage of 2 V to 4.5 V, an aqueous 55 module according to an embodiment;
solution -based electrolytic solution is not used in the lithium FIG . 13 is a schematic view of an example of a vehicle
ion secondary battery, and a nonaqueous electrolytic solu including a battery pack according to the embodiment; and
tion in which lithium salt is dissolved in an organic solvent FIG . 14 is a schematic view showing an aspect of a
is used . It has been considered to improve a composition of vehicle including the secondary battery according to
the nonaqueous electrolytic solution in order to improve 60 embodiments .
large current discharge performance and cycle life perfor
mance. However, since ion conductivity of the nonaqueous DETAILED DESCRIPTION
electrolytic solution is lower than that of the aqueous
solution -based electrolytic solution , it is difficult to lower the According to one embodiment, a secondary battery
resistance of a battery. Since an organic solvent is used in the 65 including a positive electrode , a negative electrode, and an
nonaqueous electrolyte , high temperature decomposition of electrolyte is provided . The negative electrode includes
the nonaqueous electrolyte is likely to occur. And since heat titanium -containing oxide and at least one kind of element
 US 10,727,540 B2
3 4
selected from the group consisting of B , P , Al, La, Zr, Ge, in the covering member functions as an additive element to
Zn , Sn , Ga, Pb , In , Bi, and Tl. The electrolyte includes increase a hydrogen generation overvoltage of a negative
lithium ions and a solvent containing water. electrode, hydrogen generation is suppressed , so that lithium
Furthermore , according to one embodiment, a battery ions are smoothly inserted in and extracted from the nega
module
embodiment.
includes the secondary battery according to the 5 bertive also
electrode . Since the zinc element in the covering mem
functions as a negative electrode active material, a
Yet further, according to one embodiment, a battery pack negative electrode capacity is enhanced . When the zinc
includes the secondary battery according to the embodiment. element in a metal state is contained in the negative elec
In addition , according to one embodiment, a vehicle trode , electron conductivity of the negative electrode is
includes the battery pack according to the embodiment. 10 enhanced. From these results , it is possible to achieve a
According to another embodiment, a secondary battery is secondary battery being excellent in cycle life performance ,
provided . The secondary battery includes a positive elec storage performance , and large current discharge perfor
trode , a negative electrode, and an electrolytic solution. The mance and having a high capacity .
negative electrode includes a current collector and a nega When the covering member containing an additive ele
tive electrode active material including titanium -containing 15 ment covers at least a portion of the surface of the particles
oxide. At least one of the current collector and the negative of the titanium - containing oxide, the hydrogen generation
electrode active material includes on at least a portion of a overvoltage in the negative electrode can be further
surface thereof, a covering layer including at least one kind increased , and therefore , the cycle life performance and the
of element selected from the group consisting of Zn , In , Sn, storage performance of the secondary battery can be further
Pb , Hg , Cu , Cd , Ag , and Bi. The electrolytic solution 20 improved.
includes an aqueous solvent and an electrolyte . When the electrolyte contains an anion including at least
Furthermore, according to another embodiment, a battery one kind selected from the group consisting of a chlorine ion
module is provided . The battery module includes the sec (C1'), a hydroxide ion (OHC), a sulfate ion (S04 ), and a
ondary battery according to the other embodiment. nitrate ion (NO3-), the ion conductivity of the electrolyte is
According to one embodiment,a battery pack is provided . 25 theenhanced , whereby large current discharge performance of
secondary battery can be improved .
The battery pack includes the secondary battery according to
the other embodiment When the titanium -containing oxide includes at least one
According to still another embodiment, a vehicle is pro kind selected from titanium oxide represented by a general
vided . The vehicle includes the battery pack according to the formula Li TiO2 (Osxsl) and lithium titanium oxide repre
other embodiment. 30 sented by a general formula Li4+xTis012 (x is -1sx53 ), the
hydrogen generation overvoltage in the negative electrode is
First Embodiment further increased , so that the cycle life performance and the
storage performance of the secondary battery can be further
According to a first embodiment, a secondary battery improved .
including a positive electrode , a negative electrode , and an 35 As described above , the secondary battery of each
electrolyte is provided . The negative electrode contains embodiment includes the electrolyte, the negative electrode,
particles of titanium -containing oxide and at least one kind and the positive electrode, and a separator can be interposed
of element (hereinafter referred to as an additive element) between the negative electrode and the positive electrode.
selected from the group consisting of B , P , Al, La, Zr, Ge, Further, the secondary battery of each embodiment can
Zn , Sn , Ga, Pb, In , Bi, and TI. The electrolyte contains 40 further include a container storing the electrolyte , the nega
lithium ions and a solvent containing water. In this electro tive electrode, and the positive electrode .
lyte, the ion conductivity can be increased by 10 times or Hereinafter , the electrolyte , the negative electrode, the
more as compared with a nonaqueous electrolytic solution . positive electrode , the separator, and the container will be
When such an aqueous electrolyte is combined with a described .
negative electrode containing particles of titanium -contain- 45 1) Electrolyte
ing oxide as a negative electrode activematerial , generation The electrolyte is a first electrolyte , which contains a
of hydrogen gas inhibits insertion and extraction of lithium solvent containing lithium ions and water . Examples of the
ions . The present inventors have for the first time found that electrolyte include a solution containing lithium ions, and a
when a negative electrode contains an additive element, a gel-like electrolyte including a composite of the solution and
hydrogen generation rate in titanium -containing oxide is 50 a polymer material. The solution containing lithium ions is
reduced to reduce generation of hydrogen , so that lithium prepared by, for example, dissolving a lithium salt in a
ions can be efficiently inserted in and extracted from the solvent containing water. Examples of the polymer material
negative electrode , whereby cycle life performance, storage include polyvinylidene fluoride (PVDF ), polyacrilonitrile
performance , and large current discharge performance of a (PAN ) , and polyethyleneoxide (PEO )
secondary battery are enhanced . 55 It is preferable to use water as a solvent. This is because
When the electrolyte further contains zinc ions, the capac an electrolyte having a high ion conductivity can be
ity of the secondary battery can be improved in addition to obtained . An aqueous solution may have a lithium ion
the cycle life performance, the storage performance , and the concentration in the range of not less than 2 mol/L and not
large current discharge performance . It is assumed that this more than 10 mol/ L . It is considered that when the lithium
is due to themechanism to be described as follows. Zinc ions 60 ion concentration is high , free water molecules are reduced ,
in an electrolytic solution may be deposited as zinc as metal and a hydrogen generation suppression effect can be
or a compound of zinc ( for example, zinc oxide or zinc enhanced . Thus, the concentration is more preferably in the
hydroxide ) on a surface of particles of titanium -containing range of not less than 4 mol/ L and not more than 10 mol/L
oxide by charging such as initial charging. Thus, at least a and stillmore preferably in the range ofnot less than 6 mol/L
portion of the surface of the particles of the titanium- 65 and not more than 10 mol/L .
containing oxide can be covered with a covering member Examples of lithium salt include LiCl, LiBr, LiOH ,
containing Zn as a zinc element. Since the Zn ( zinc element ) Li2SO4, LiNO3, Li_C204, and LiB [(OCO )2 ]2. One or plural
 US 10,727,540 B2
5 6
kinds of lithium ions may be used . It is preferable because (B203 ), alumina (Al2O3), zirconia oxide (ZrO2), germanium
an electrolyte containing LiCl can have a high lithium ion oxide (Ge02), zinc oxide (ZnO ), and lead oxide (PbO ).
concentration of not less than 4 mol/L or not less than 6 Examples ofhydroxides of the additive element include zinc
mol/ L . hydroxide (Zn (OH )2). On the other hand , it is preferable to
It is preferable that an electrolyte contains anion species 5 use an oxide solid electrolyte having high stability in an
including at least one kind selected from the group consist alkali aqueous solution and having lithium ion conductivity .
ing of a chlorine ion (C1- ), a hydroxide ion (OH-), a sulfate In particular , an oxide solid electrolyte having a garnet
ion (SO42-), and a nitrate ion (NO3-). Those anion species
can be obtained by , for example , dissolving lithium salt, crystalCON -
structure , a perovskite crystal structure , or a NASI
type crystal structure has advantages of chemical
such as Lici, LiOH , Li2SO4, or LiNO3, in a solvent. 10
stability in an alkaline aqueous solution , a high reduction
The electrolyte may contain salt of an additive element. resistance , and a wide potential window . Examples of the
One or plural kinds of additive elements may be contained oxide solid electrolyte having the garnet crystal structure
in the salt. It is preferable that this salt can be dissolved in include ListALaz- M2012 ( A is at least one kind of ele
a solvent containing water. Examples of the salt include
ZnSO4. When the electrolyte contains ZnSO4, zinc ions 15 Mis
mentNbselected from the group consisting of Ca, Sr, and Ba ,
and/or Ta , and x is 0sxs2), LizM2_xL2012 (M is Ta
exist in the electrolyte (for example, in a solvent). As a and /or Nb , L is Zr, and x is 0sxs2 ), Li7-32A1, LazZr2012 (X
result, metallic zinc or a compound of zinc is deposited on
a surface of titanium -containing oxide particles by charging is Osxs0.3 ), and Li,LazZr2012 . Among them , since
such as initial charging, whereby at least a portion of the Li6.25A10.25LazZr2012 and Li LazZr2012 each have a high
surface of the titanium -containing oxide particles can be
covered with a zinc -containing covering member . Thus, the
20 large
ion conductivity and are each electrochemically stable , the
current discharge performance and the cycle life per
capacity of the secondary battery can be improved in addi formance of the secondary battery are improved . As the
tion to the cycle life performance , the storage performance , oxide solid electrolyte having the perovskite crystal struc
and the large current discharge performance . ture, Liz:La2/3 -xTiO3 (0.05sxs0.15 ) is preferably used . As
ApH value of an aqueous solution containing lithium ions 25 the oxide solid electrolyte having the NASICON -type crys
is preferably in the range ofnot less than 3 and not more than tal structure, Li1.3Ti, 7A10.3 (PO4)3 is preferably used. As an
13. If the pH value is in this range , hydrogen generation can oxide solid electrolyte having a y- Li3PO4 crystal structure,
be reduced . Consequently, the cycle life performance and Li14ZnGe4016 or Liz.Ge... V0.404 is preferably used .
the storage performance can be enhanced . More preferable Preferred examples of oxides include zirconia oxide
anranges
acidicareregion
not lessandthan pH 4thanandpHnot7.5moreand than
not less pH 6.5thanin 30 (ZrO2), alumina (Al2O3), zinc oxide (Zno ), and germanium
notmore
pH 12 in an alkaline region . When the pH value is in the oxide for
(GeO2). Those oxides have a high suppression effect
hydrogen generation . When A1,03 is used , hydrogen
acidic region or the alkaline region , corrosion reaction of an generation is suppressed
additive element such as zinc can be suppressed while the storage performance, and are
the cycle life performance and
enhanced .
improving the ion conductivity of an electrolyte . The pH 35 Since zinc as metal or a compound of zinc ( for example ,
value of the electrolyte can be adjusted into a range in the zinc oxide or zinc hydroxide) has a high hydrogen overvolt
acidic region by adding sulfuric acid to the electrolyte. On
the other hand , the pH value of the electrolyte can be age and functions as a negative electrode active material,
adjusted into a range in the alkaline region by adding LiOH hydrogen generation is suppressed , and a high capacity
to the electrolyte . 40 negative electrode can be achieved . Since zinc as metal is
2 ) Negative Electrode excellent in electron conductivity , it can serve as an electro
The negative electrode includes a negative electrode conductive agent, so that the electron conductivity of a
current collector and a negative electrode active material negative electrode can be enhanced .
containing layer provided on one side or both sides of the Composite particles in which at least a portion of a surface
current collector and including an activematerial, an electro- 45 of particles of an additive element is covered with a layer or
conductive agent, and a binder. film including oxide of the additive element may be used .
Examples of the negative electrode current collector The hydrogen generation overvoltage on a surface of metal
include a foil, a porous body, and a mesh . Examples of oxide can be increased as compared with a surface of ametal
materials forming the negative electrode current collector simple substance . In particular, a composite in which at least
include electrically conductive materials such as metals and 50 a portion of a surface of Al particles is covered with a layer
alloys. Examples of metals include nickel, stainless steel, or a film including alumina ( A1203 ) and a composite in
iron , copper, aluminum , and zinc . It is preferable for the which at least a portion of a surface of Zn particles is
negative electrode current collector to include a metal plate covered with a layer or a film including zinc oxide (ZnO )
whose surface is covered with a layer or film ofmetal oxide each have a high hydrogen overvoltage , and thus it is
by oxidation treatment. The negative electrode current col- 55 preferable . It is preferable that alumina is formed by apply
lector may be made of one or more kinds of materials . ing alumite treatment to Al body .
A negative electrode active material-containing layer fur Examples of alloys containing an additive element
ther contains at least one kind of element (hereinafter include a Zn alloy, a Bi— In — Pb -based alloy, a Bi — In
referred to as an additive element) selected from the group Ca -based alloy, and a Bi - In - Al alloy. Those alloys can
consisting of B , P, Al, La , Zr, Ge, Zn , Sn , Ga, Pb , In , Bi, and 60 increase the hydrogen generation overvoltage .
T1. Each additive element may take any form including a The additive element allows containing of a negative
simple substance, a compound, and an alloy. Each additive electrode active material-containing layer by mixing par
element may be present in a negative electrode in a plurality ticles containing the additive element with titanium -contain
of forms such as a simple substance and a compound . ing oxide particles. Although the shape of particles contain
Examples of compounds of each additive element include 65 ing this additive element is not limited particularly , the
oxide, hydroxide, and an oxide solid electrolyte . Examples particles may have a spherical shape, an elliptical shape, a
of oxides of the additive element include boron oxide flat shape, a fibrous shape , or the like.
 US 10,727,540 B2
7 8
When additive element- containing particles are mixed The negative electrode active material contains one or
with negative electrode active material particles, it is desir plural kinds of titanium -containing oxides . Examples of the
able that a mixing ratio satisfies the following formula ( 1): titanium -containing oxides include lithium titanium oxide ,
2 % by weights {W ,/W2} x100s50 % by weight ( 1) 5
titanium oxide, niobium titanium oxide, and sodium nio
bium titanium oxide. The Li insertion potential of the
In the formula (1), W represents the weight of the titanium -containing oxide is desirably in a range of not less
additive element-containing particles, and W , is the weight than 1V (vs. Li/Li+ ) and not more than 3V ( vs. Li/Li*).
of the negative electrode active material particles. When a Examples of lithium titanium oxides include spinel struc
surface of the titanium -containing oxide particles is covered ture lithium titanium oxide ( for example , a general formula
with a covering member, W2 is the total weight of the 10 Li4 +xTis012 (x is -1sxs3)), lithium titanium oxide having a
titanium -containing oxide particles and the covering mem ramsdellite structure (for example , Li2+xTi20 , (-1sx53 )),
ber. Li1+ xTi_04 (Osxsl), Lil.1 +xTi1.804 (Osxsl),
When the weight ratio of an additive element is not less Li1.07+xTi1.8604 (Osxsl), and LiTiO2 (0 < xsl).
than 2 % by weight and not more than 50 % by weight, the Examples of titanium oxides include titanium oxide hav
electron conductivity in a negative electrode is enhanced , 15 ing a monoclinic structure, titanium oxide having a rutile
and hydrogen generation is significantly suppressed . There structure , and titanium oxide having an anatase structure . In
fore , lithium ions can be smoothly inserted in and extracted the titanium oxide having each crystal structure, the com
from the negative electrode active material, whereby the position before charging can be represented by TiO2, and the
large current discharge performance of a battery can be composition after charging can be represented by Li TiO2 (X
enhanced . A more preferable range of the weight ratio is not 20 is 0sxsl). In the titanium oxide having a monoclinic struc
less than 3 % by weight and notmore than 30 % by weight. ture, the structure before charging can be represented as
The weight ratio of the additive element is measured by TiO , ( B ) .
the following method . A secondary battery is disassembled Examples of niobium oxides include niobium oxide rep
in a glove box filled with argon to take out a negative resented by Li TiM ,Nb2-60770 (Osas5 , Osbs0.3, 0s | s0.3 ,
electrode therefrom . A negative electrode active material- 25 Osos0.3 , and M is at least one kind of element selected from
containing layer is separated from a negative electrode the group consisting of Fe, V , Mo, and Ta ).
current collector of the taken out negative electrode . The Examples of sodium niobium titanium oxides include
negative electrode active material-containing layer is orthorhombic Na-containing niobium titanium composite
washed with water or cleaned with a neutral aqueous solu oxide represented by a general formula Liz- „Naz- „ MI,
tion and then dried . Thereafter, the additive element and the 30 Ti6 -v -2Nb,M2,014 +8 (Osvs4 , 0 < w < 2 , 0 < x < 2 , 0 < ys6 ,
negative electrode active material are separated using a Osz < 3 , -0.5sds0.5 , M1 includes at least one selected from
specific gravity difference between the additive element and Cs, K , Sr, Ba, and Ca, and M2 includes at least one selected
the negative electrode active material. The separation is from Zr, Sn , V , Ta , Mo, W , Fe, Co, Mn, and Al).
performed by a method of putting a mixed powder in an Preferable examples of titanium -containing oxides
organic solvent and separating the additive element and the 35 include titanium oxide having an anatase structure, titanium
negative electrode active material based on a difference in oxide having a monoclinic structure , and lithium titanium
settling velocity or a method of separating the additive oxide having a spinel structure. In each titanium -containing
element and the negative electrode active material by using oxide and the lithium titanium oxide, since the Li insertion
a dry type gravity sorting /separator device . The weights of potential is in a range ofnot less than 1.4 V (vs. Li/Li*) and
the additive element and the negative electrode active mate- 40 not more than 2 V (vs. Li/Li*), the hydrogen generation
rial are measured to calculate the weightratio of the additive suppression effect can be enhanced by combining the tita
element from the formula ( 1 ). nium -containing oxide with an electrolytic solution being an
At least a portion of the surface of titanium -containing aqueous solution containing lithium ions.
oxide particles can be covered with a covering member Consequently , a negative electrode can allow lithium ions
containing the additive element. Examples of the covering 45 to be efficiently inserted in and extracted from . Titanium
method include, in addition to plating and evaporation , a oxide having an anatase structure has the most excellent
method of allowing an electrolytic solution of a secondary hydrogen generation suppression effect, followed by tita
battery to contain the additive element and allowing the nium oxide having a monoclinic structure, lithium titanium
additive element in the electrolytic solution to be deposited oxide having a spinel structure, and niobium titanium oxide.
on titanium -containing oxide particles by charging . A thick- 50 By virtue of the use of those titanium -containing oxides, an
ness of the covering member including the additive element aluminum foil or an aluminum alloy foil used as a positive
is preferably not less than 0.01 um and notmore than 1 um . electrode current collector can be used like a negative
If the thickness is less than this range , hydrogen generation electrode current collector, instead of a copper foil , so that
increases, and the life performance may be reduced . On the weight reduction and cost reduction can be achieved . This is
other hand , if the thickness is more than this range, resis- 55 advantageous for an electrode structure as a bipolar struc
tance increases, and the large current discharge performance ture. The lithium titanium oxide having a spinel structure
may be reduced . A more preferable range is not less than can reduce a change in volume due to a charge /discharge
0.01 um and not more than 0.5 um . Although the covering reaction .
member containing the additive element may have a granu A negative electrode active material is contained in the
lar shape, a fibrous shape , a layered shape , or the like , the 60 form of particles in a negative electrode active material
shape is not limited particularly. The thickness of the cov containing layer. Negative electrode active material particles
ering member can be measured by observation using a may be independent primary particles, secondary particles
scanning electron microscope (SEM ) or a transmission as agglomerates of primary particles, or a mixture of the
electron microscope ( TEM ). independent primary particles and the secondary particles .
The negative electrode active material-containing layer 65 The shape of particles is not limited particularly and may be ,
may further contain titanium oxide ( TiO , TiO2) in addition for example , a spherical shape , an elliptical shape, a flat
to the additive element. shape, or a fibrous shape .
 US 10,727,540 B2
9 10
An average particle size (diameter ) of secondary particles in the range of 80 % by weight to 95 % by weight for the
of a negative electrode active material is preferably not less negative electrode active material, 3 % by weight to 18 % by
than 5 um and more preferably not less than 7 um and not weight for the electro -conductive agent, and 2 % by weight
more than 20 um . If the average particle size is in this range, to 7 % by weight for the binder.
the hydrogen generation suppression effect can be enhanced . 5 The negative electrode is produced by , for example,
A negative electrode active material in which the average suspending the negative electrode active material, the elec
particle size of secondary particles is not less than 5 um is tro -conductive agent, and the binder in an appropriate sol
obtained by the following method , for example . An active vent, applying the suspended matter on a current collector,
material raw material is reacted and synthesized to produce drying, and pressing the current collector by , for example ,
an active material precursor having an average particle size 10 heat-pressing.
of not more than 1 um . After that, the precursor is baked as 3 ) Positive Electrode
a heat treatment and then ground using a grinder such as a The positive electrode has a positive electrode current
ballmill and a jet mill. Then, in the heat treatment, an active collector and a positive electrode active material-containing
material precursor is aggregated to be grown to secondary layer provided on one side or both sides of the current
particles having a large particle size . 15 collector and including an active material, an electro -con
An average particle size of primary particles of a negative ductive agent, and a binder.
electrode active material is desirably not more than 1 um . As the positive electrode active material, a positive elec
Consequently, a diffusion distance of lithium ions inside trode active material capable of allowing Li to be inserted
active material particles is reduced , and a specific surface and extracted may be used . Examples of the positive elec
area increases. Thus, excellent high input performance (i.e., 20 trode active material include lithium manganese composite
rapid charge performance ) is obtained . On the other hand , if oxide , lithium nickel composite oxide , lithium cobalt alu
an average particle size is small , particles are likely to minum composite oxide, lithium nickel cobalt manganese
gregate , and most of an electrolyte may be distributed in composite oxide , spinel-type lithium manganese nickel
a negative electrode to cause depletion of the electrolyte in composite oxide, lithium manganese cobalt composite
a positive electrode . Therefore , the lower limit value of the 25 oxide, lithium iron oxide, lithium fluorinated iron sulfate,
average particle size is desirably 0.001 um . A more prefer and a phosphate compound having an olivine crystal struc
able average particle size is not less than 0.1 um and not ture ( such as Li FePO4 (Osxsl) and Li MnPO4 (Osxsl )) .
more than 0.8 um . The phosphate compound having an olivine crystal structure
In negative electrode active material particles , it is desir is excellent in heat stability .
able that the specific surface area according to a BET 30 Examples of a positive electrode active material capable
method using N2 absorption is in a range of not less than 3 of obtaining a high positive electrode potential include
m²/g and not more than 200 m ~/g . Consequently , an affinity lithium manganese composite oxides such as LiMn204
with an electrolyte of a negative electrode can be further (0 < xsl) and Li,MnO , (0 < xsl ), lithium nickel aluminum
enhanced . composite oxides such as Li,Ni - A1,02 (0 < xsl, 0< ysl ),
1

A specific surface area of a negative electrode active 35 lithium cobalt composite oxides such as Li C002 (0 < xsl),
material-containing layer (except for a current collector) is lithium nickel cobalt composite oxides such as
desirably in a range of not less than 3 m²/g and not more than Li Ni ---- Co ,Mn 02 (0 < xs1 , 0 < ysl, Oszsl ), lithium man
50 m²/g. A more preferable range of the specific surface area ganese cobalt composite oxides such as Li,Mn, Co-, 02
is not less than 5 m²/g and not more than 50 m²/g . The (0 < xs1, 0 < ysl), spinel-type lithium manganese nickel com
negative electrode active material-containing layer may be a 40 posite oxides such as Li Mn2-,Ni,04 (0 <xsl, 0 < y < 2),
porous layer provided on a current collector, and including lithium phosphorus oxides having an olivine crystal struc
a negative electrode active material, an electro -conductive ture , such as Li FePO4 (0 < xsl), Li, Fe -„Mn,P04 (0 < xsl,
agent, and a binder. Osysl) and Li,CoPO4 (0 < xsl), and fluorinated iron sulfate
A porosity of a negative electrode (except for a current (such as Li, FeSO , F (0 < xsl )).
collector) is desirably in a range of 20 to 50 % . Consequently, 45 According to lithium nickel aluminum composite oxides,
it is possible to obtain a high -density negative electrode lithium nickel cobalt manganese composite oxides , and
excellent in affinity with an electrolyte . A more preferable lithium manganese cobalt composite oxides, reaction with
range of the porosity is 25 to 40 % . an electrolyte under a high temperature environment can be
Examples of the electro -conductive agent include carbon suppressed , so that a battery life can be significantly
materials , such as acetylene black , carbon black , coke, 50 increased . Composite oxide represented by
carbon fibers, or graphite , and metal powders such as nickel Li Ni1 -v-zCo,Mn_02 (0sxs1.1 , Osys0.5 , and 0szs0.5 ,more
or zinc . One or plural kinds of electro -conductive agents preferably 0 < xsl.1 , 0 < ys0.5, and 0 < zs0.5) is advantageous
may be used. Since hydrogen is generated from a carbon for a high temperature durability life .
material, it is desirable to use a metal powder as an electro Particles of a positive electrode active material may
conductive agent. When zinc particles are used in an addi- 55 include independent primary particles, secondary particles
tive element, since the zinc particles serve as an electro as agglomerates of primary particles , or both the indepen
conductive agent, another electro - conductive agent is not dent primary particles and the secondary particles .
required . The zinc particles further serve as a negative An average particle size (average particle diameter ) of
electrode active material. Thus, when the zinc particles are primary particles of the positive electrode active material is
used in the additive element, hydrogen generation is sup- 60 preferably not more than 1 um and more preferably 0.05 to
pressed , and a high capacity negative electrode excellent in 0.5 um . It is preferable that at least a portion of surfaces of
electron conductivity can be achieved . the particles of the positive electrode active material is
Examples of the binder include polytetrafluoroethylene covered with a carbon material. The carbon material may
(PTFE ), fluororubbers, styrene butadiene rubbers , and core / take the form of a layer structure, a particle structure , or an
shell binder. One or plural kinds of binders may be used . 65 aggregate of particles.
Themixing ratio of the negative electrode active material, When the positive electrode active material particles take
the electro - conductive agent, and the binder is preferably set the form where the secondary particles and the independent
 US 10,727,540 B2
11 12
primary particles are mixed, the average particle size of the charging , float charging, and over-charge, and a short-circuit
positive electrode active material particles is preferably not between the negative electrode and a positive electrode due
less than 0.8 um and not more than 15 um . to dendrite precipitation of lithium metal does not occur. A
As a positive electrode current collector, a foil, a porous more preferable range is 62% to 80 % .
body, or a mesh is preferably used. Examples of electrically 5 It is preferable that the separator has a thickness of not
conductive materials contained in the positive electrode less than 20 um and not more than 100 um and a density of
current collector include aluminum alloy, and metals such as not less than 0.2 g/cm² and not more than 0.9 g/cm3. If the
nickel, stainless steel, iron , copper, or aluminum . thickness and the density of the separator are in these ranges,
Examples ofan electro -conductive agent used for enhanc mechanical strength and a reduction in battery resistance can
ing electron conductivity and suppressing contact resistance 10 be balanced , so that a high output secondary battery in which
with a current collector include acetylene black , carbon an internal short-circuit is suppressed can be provided .Heat
black , graphite , and carbon fiber having an average fiber shrinkage of the separator under a high temperature envi
diameter of not more than 1 um . One or plural kinds of ronment is small , and good high temperature storage per
electro -conductive agents may be used . formance can be exhibited .
Examples of a binder for binding an active material and 15 5 ) Container
the electro - conductive agent include polytetrafluoroethylene As a container containing a positive electrode, a negative
(PTFE ), polyvinylidene fluoride (PVdF ), and fluororubbers. electrode , and an electrolyte, a metal container, a laminate
One or plural kinds of binders may be used . film container, or a resin container, such as a polyethylene
The mixing ratio of the positive electrode active material, container or a polypropylene container, may be used .
the electro -conductive agent, and the binder is preferably set 20 As the metal container, a rectangular or cylindrical metal
in the range of not less than 80 % by weight and notmore can made of nickel, iron , stainless steel, or the like may be
than 95 % by weight for the positive electrode active mate used .
rial, not less than 3 % by weight and not more than 18 % by Each plate thickness of the resin container and the metal
weight for the electro -conductive agent, and not less than container is preferably not more than 1 mm and more
2 % by weight and not more than 7 % by weight for the 25 preferably not more than 0.5 mm . A more preferable range
binder. When the mixing ratio of the electro - conductive is not more than 0.3 mm . The lower limit value of the plate
agent is not less than 3 % by weight, the above effect can be thickness is desirably 0.05 mm .
exercised , and when the mixing ratio of the electro - conduc Examples of laminate films include a multilayer film in
tive agent is not more than 18 % by weight, decomposition which a metal layer is covered with a resin layer. Examples
of an electrolyte on a surface of the electro - conductive agent 30 of themetal layer include a stainless steel foil , an aluminum
under high temperature preservation can be reduced . When foil, and an aluminum alloy foil . As the resin layer, a
the mixing ration of the binder is not less than 2 % by weight, polymer such as polypropylene (PP ), polyethylene (PE ),
sufficient electrode strength is obtained , and when the mix nylon , or polyethylene terephthalate (PET) may be used . A
ing ration of the binder is not more than 7 % by weight, an preferable range of a thickness of the laminate film is not
insulating portion of an electrode can be decreased . 35 more than 0.5 mm . A more preferable range is not more than
The positive electrode is produced by, for example, sus 0.2 mm . The lower limit value of the thickness of the
pending the positive electrode active material, the electro laminate film is desirably 0.01 mm .
conductive agent, and the binder in an appropriate solvent, The secondary battery according to the embodiments is
applying the suspended matter on a positive electrode cur applicable to secondary batteries in various forms such as a
rent collector, drying , and pressing the current collector. A 40 rectangular form , a cylindrical form , a flat form , a thin form ,
positive electrode pressing pressure is preferably in the or a coin form . The secondary battery according to the
range of 0.15 ton /mm to 0.3 ton /mm . If the positive elec embodiments is preferably a secondary battery having a
trode pressing pressure is in this range, it is preferable bipolar structure. Consequently, it is advantageous in terms
because adhesion ( i.e., peel strength ) between the positive of enabling production of a plural of series cells as one cell.
electrode active material-containing layer and the positive 45 An example of the secondary battery according to the
electrode current collector is enhanced , and , at the same embodiments will be described with reference to FIGS. 1 to
time, the elongation percentage of the positive electrode 4 .
current collector is not more than 20 % . FIGS. 1 and 2 show an example of a secondary battery
4 ) Separator using a metal container.
A separatormay be disposed between a positive electrode 50 An electrode group 1 is stored in a rectangular cylindrical
and a negative electrode . Examples of the separator include metal container 2. The electrode group 1 has a structure in
nonwoven fabrics , films, and paper. Examples of materials which a positive electrode 3 and a negative electrode 4 are
contained in the separator include polyolefin , such as poly spirally wound to provide a flat shape while a separator 5 is
ethylene or polypropylene, and cellulose. Preferable interposed between the positive electrode 3 and the negative
examples of the separator include nonwoven fabrics con- 55 electrode 4. An electrolyte (not shown) is held by the
taining cellulose fibers and porous films containing poly electrode group 1. As shown in FIG . 2 , belt- like positive
olefin fibers. The porosity of the separator is preferably not electrode leads 6 are electrically connected to a plural of
less than 60 % . A fiber diameter is preferably not more than portions of an end of the positive electrode 3 located on an
10 um . When the fiber diameter is not more than 10 um , an end surface of the electrode group 1. On the other hand ,
affinity with an electrolyte of the separator is enhanced , so 60 belt-like negative electrode leads 7 are electrically con
that battery resistance can be reduced . A more preferable nected to a plural of portions of an end of the negative
range of the fiber diameter is not more than 3 um . In a electrode 4 located on the end surface of the electrode group
cellulose fiber containing nonwoven fabric having a porosity 1. The positive electrode leads 6 are bundled to be electri
ofnot less than 60 % , impregnation of an electrolyte is good , cally connected to a positive electrode conductive tab 8. A
and high output performance can be exhibited from low 65 positive electrode terminal is constituted of the positive
temperature to high temperature . The separator does not electrode leads 6 and the positive electrode conductive tab 8 .
react with a negative electrode in long term storage after The negative electrode leads 7 are bundled to be electrically
 US 10,727,540 B2
13 14
connected to a negative electrode conductive tab 9. A discharge performance of the secondary battery including an
negative electrode terminal is constituted of the negative aqueous electrolyte can be enhanced .
electrode leads 7 and the negative electrode conductive tab
9. A metal sealing plate 10 is fixed to an opening of themetal Second Embodiment
container 2 by welding or the like . The positive electrode 5
conductive tab 8 and the negative electrode conductive tab According to a second embodiment, a battery module in
9 are drawn to the outside through a take-out hole formed in which a secondary battery is a unit cell can be provided . The
the sealing plate 10. An inner peripheral surface of each secondary battery of the first embodimentmay be used as the
take- out hole of the sealing plate 10 is covered with an 10 secondary battery of the second embodiment.
insulating member 11 in order to avoid a short-circuit due to Examples of the battery module include a battery module
contact between the positive electrode conductive tab 8 and including, as a structural unit, a plural of unit cells electri
the negative electrode conductive tab 9 . cally connected in series or parallel and a battery module
FIGS . 3 and 4 show an example of a secondary battery including a unit constituted of a plural of unit cells electri
using a container member made of a laminate film . cally connected in series or a unit constituted of a plural of
The laminate type electrode group 1 is stored in a bag - like unitThecells
15 electrically connected in parallel.
battery module may be contained in a housing . As the
container 2 made from a laminate film in which ametal layer housing, ametal can made of aluminum alloy , iron , stainless
is interposed between two resin films. The laminate type steel, or the like or a plastic container may be used , for
electrode group 1 has a structure in which the positive example . A plate thickness of the container is desirably not
electrode 3 and the negative electrode 4 are alternately 20 less than 0.5 mm .
stacked with the separator 5 being interposed therebetween Examples of an embodiment in which a plural of second
as shown in FIG . 4. There are a plural of the positive ary batteries are electrically connected in series or parallel
electrodes 3 , and each of which includes a current collector include an embodiment in which a plural of secondary
3a and a positive electrode active material-containing layer batteries each provided with a container are electrically
3b which is provided on both surfaces of the current col- 25 connected in series or parallel and an embodiment in which
lector 3a . There are a plural of the negative electrodes 4 , and a plural of electrode groups contained in a common housing
each of which includes a current collector 4a and a negative are electrically connected in series or parallel. As a specific
electrode active material- containing layer 4b which is pro example of the former embodiment, positive electrode ter
vided on both surfaces of the current collector 4a. One side minals and negative electrode terminals of a plural of
of the current collector 4a ofeach of the negative electrodes 30 secondary batteries are connected by a metalbus bar (made
4 is projected from the positive electrode 3. The projected of aluminum , nickel, or copper, for example ). As a specific
current collector 4a is electrically connected to a belt-like example
groups in
of the latter embodiment, a plural of electrode
a state of being electrochemically insulated by
negative electrode terminal 12. A leading end of the belt -like bulkheads are contained in one housing , and these electrode
negative electrode terminal 12 is drawn to the outside from 35 groups are electrically
the container 2. Further, although not shown, as for the of batteries electricallyconnected in series. When the number
positive electrode 3 , a side of the current collector 3a is 5 to 7 , voltage compatibility with ina series
connected is in the range of
projected from the negative electrode 4 and positioned at an improved . In order to further improve the voltagebattery
lead storage
compat
is
opposite side of the projected side of the current collector ibility with the lead storage battery , it is preferable that five
4a . The current collector 3a projected from the negative 40 or six unit cells are connected in series.
electrode 4 is electrically connected to a belt- like positive An example of the battery module will be described with
electrode terminal 13. A leading end of the belt - like positive reference to FIG . 5. A battery module 31 shown in FIG . 5 is
electrode terminal 13 is positioned at an opposite side of the provided with , as unit cells , rectangular secondary batteries
negative electrode terminal 12 and is drawn to the outside ( for example , FIGS . 1 and 2 ) 324 to 32 , according to the first
from one side of the container 2 . 45 embodiment. The positive electrode conductive tab 8 of the
The secondary battery shown in FIGS. 1 to 4 may include battery 32 , and the negative electrode conductive tab 9 of the
a safety valve for releasing hydrogen gas, generated in the battery 322 located adjacent thereto are electrically con
container, to the outside. The safety valve to be used may be nected by a lead 33. Further, the positive electrode conduc
of the return type , in which the safety valve operates when tive tab 8 of the battery 322 and the negative electrode
the internal pressure exceeds a set value and the safety valve 50 conductive tab 9 of the battery 323 located adjacent thereto
are electrically connected by the lead 33. As described
functions as a sealing plug when the internal pressure is
reduced , or the non -return type , in which once the safety above , the batteries 32 to 325 are connected in series.
valve operates , the function as a sealing plug is not restored . Since the battery module of the second embodiment
Although the secondary battery shown in FIGS. 1 to 4 is of 55 includes the secondary battery of the first embodiment, a
a sealed type , when the secondary battery is provided with battery module excellent in cycle life performance , storage
a circulation system for returning hydrogen gas to water, the performance, and large current discharge performance can
secondary battery may be an open system . be achieved . The secondary battery of the first embodiment
According to the first embodiment, hydrogen generation is excellent in compatibility with a lead storage battery.
Thus, a battery module in which five secondary batteries are
is suppressed and the lithium ions can be efficiently inserted 60 connected in series can be used as an alternative to lead
and extracted by the negative electrode since the secondary storage battery for power supply.
battery includes the negative electrode, containing titanium
containing oxide and at least one kind of element selected Third Embodiment
from the group consisting of B , P, A1, La , Zr,Ge, Zn , Sn , Ga,
Pb , In , Bi, and TI, and the electrolyte containing lithium ions 65 According to the third embodiment, it is possible to
and a solvent containing water . As a result, the cycle life provide a battery pack including at least one secondary
performance, the storage performance, and the large current battery of the first embodiment and a circuit portion for
 US 10,727,540 B2
15 16
controlling charge/discharge of the secondary battery . When wiring 66a and a minus wiring 66b between the protective
a battery pack includes a plural of secondary batteries, the circuit 58 and the terminal 59 for passing current to external
battery module of the second embodiment may be used in devices under a predetermined condition . The predeter
the battery pack . mined condition may include, for example, a condition in
In a battery pack , a circuit portion may be connected to a 5 which the detection temperature of the thermistor 57 is more
secondary battery before being installed in a vehicle such as than a predetermined temperature . Also , the predetermined
an automobile or an electronic device; however, the battery condition may include a condition in which over-charge ,
pack of the embodiment includes a battery pack in which a over-discharge, and overcurrent of the unit cell 51 are
circuit portion of a vehicle such as an automobile is con detected . Each of the unit cells 51 and the battery module 55
nected to a secondary battery . 10 are subjected to the detection of the over-charge and the like .
An example of a battery pack will be described with When each of the unit cells 51 is detected , a battery voltage
reference to FIG . 6. A battery pack 40 includes a battery may be detected , or a positive electrode potential or a
module including a secondary battery shown in FIGS. 3 and negative electrode potential may be detected . In the latter
4. The battery pack 40 includes a housing 41 and a battery case, a lithium electrode used as a reference electrode is
inserted into each of the unit cells 51. In the cases of FIG .
module 42 contained in the housing 41. In the battery 15 7 and FIG . 8, wirings 67 are connected to each of the unit
module 42, a plural of (for example , five) secondary batter cells 51 for voltage detection , and detection signals are
ies 431 to 43 , are electrically connected in series. The transmitted to the protective circuit 58 through these wirings
secondary batteries 43 , to 43 , are stacked in a thickness 67 .
direction . The housing 41 has openings 44 in the upper A rubber or resin protective sheet 68 is disposed on each
portion and four side surfaces. The side surface from which 20 of three side surfaces of the battery module 55 except for the
positive and negative electrode terminals 13 and 12 of the side surface from which the positive electrode terminal 53
secondary batteries 43 , to 43 , are projected is exposed to the and the negative electrode terminal 52 are projected .
openings 44 of the housing 41. A positive electrode terminal The battery module 55 is stored in a housing container 69
45 for output of the battery module 42 has a belt shape, one together with the protective sheets 68 and the printed wiring
end is electrically connected to the positive electrode ter- 25 board 56.on Inbothother wordssurfaces
, the protective
in a long sidesheets 68 areof
minal 13 of any of the secondary batteries 43 , to 435 , and the arranged of inner direction
other end is projected from the upper portion of the housing the housingof container 69 and one inner surface in a short side
41 while being projected through the opening 44 of the direction the housing container 69 , and the printed wiring
housing 41. On the other hand , a negative electrode terminal board 56 is disposed on the other inner surface in a short side
direction . The battery module 55 is positioned in a space
46 foris output
end of theconnected
electrically battery module
to the42negative
has a belt shape, ter
electrode one 30 surrounded by the protective sheets 68 and the printed
minal 12 ofany of the secondary batteries 43, to 435, and the wiring board 56. A lid 70 is attached to a top face of the
housing container 69 .
other end is projected from the upper portion of the housing For fixing the battery module 55 , a thermally -shrinkable
41 while being projected through the opening 44 of the tape may be used instead of the adhesive tape 54. In that
housing 41. 35
case , after protective sheets are arranged at both of side faces
Another example of a battery pack will be described in of a battery module, it is surrounded by a thermally
detail with reference to FIGS. 7 and 8. A plural of unit cells shrinkable tape, and then the thermally -shrinkable tape is
51 constituted of flat- type secondary batteries are stacked thermally shrunk to bind the battery module .
such that a negative electrode terminal 52 and a positive In FIGS. 7 and 8 , although an embodiment in which the
electrode terminal 53 extending outward are arranged in the 40 unit cells 51 are connected in series is described , they may
same direction , and they are fastened with an adhesive tape be connected in parallel, for increasing a battery capacity.
54 to form a battery module 55. Those unit cells 51 are Battery packs may be connected in series or in parallel.
electrically connected to each other in series as shown in The embodiments of the battery pack may be appropri
FIG . 8 . ately altered depending on the application thereof. The
A printed wiring board 56 is disposed facing side surfaces 45 application of the battery pack may include applications in
of the unit cells 51 from which the negative electrode which charging/discharging at high current is desired . Spe
terminal52 and the positive electrode terminal53 extend . As cific examples of the applications include power sources for
shown in FIG . 8 , a thermistor 57, a protective circuit 58 , and digital cameras , a stationary battery, and vehicle - installed
a terminal 59 for passing current to external devices are batteries for two- or four -wheel hybrid electric vehicles,
installed on the printed wiring board 56. An insulating plate 50 two or four-wheel electric vehicles, motor- assisted
(not shown ) is attached to a surface of the printed wiring bicycles, and a railway car . Vehicle- installed batteries are
board 56 facing the battery module 55, in order to avoid particularly preferred .
unnecessary connect with wirings of the battery module 55 . Since the battery pack of the third embodiment which has
A positive electrode lead 60 is connected to the positive been described above includes the secondary battery of the
electrode terminal 53 positioned in the undermost layer of 55 first embodiment, a battery pack excellent in cycle life
the battery module 55 , and its tip is inserted into a positive performance , storage performance , and large current dis
electrode connector 61 of the printed wiring board 56 to charge performance can be achieved . Thus, according to the
electrically connect it. A negative electrode lead 62 is embodiment, it is possible to provide a battery module and
connected to the negative electrode terminal52 positioned in a battery pack suitable as an alternative power supply to a
the uppermost layer of the battery module 55, and its tip is 60 lead battery used as a starter power supply for a vehicle or
inserted into a negative electrode connector 63 of the printed as a vehicle- installed secondary battery to be installed in a
wiring board 56 to electrically connect it . Those connectors hybrid car.
61 and 63 are connected to the protective circuit 58 through
wirings 64 and 65 formed on the printed wiring board 56 . Fourth Embodiment
The thermistor 57 detects a temperature of the unit cell 51 , 65
and the detection signal thereof is transmitted to the protec When an electrolytic solution including an aqueous sol
tive circuit 58. The protective circuit 58 can interrupt a plus vent is used in view of safety, it is difficult to obtain a battery
 US 10,727,540 B2
17 18
voltage of about 3 to 4 V ,which is obtained in a nonaqueous not only the negative electrode active material but also both
lithium ion battery (a nonaqueous electrolyte battery ). When the negative electrode current collector and the negative
the aqueous solvent is used , it is necessary to use a negative electrode electro -conductive agent may serve as reaction
electrode material having a relatively high operating poten fields for hydrogen generation . Thus, in embodiments , it is
tial such as LiV204 or LiTi, (PO4) 3, in order to avoid 5 preferable that the above -described covering layer is dis
hydrogen generation due to electrolysis on the negative posed both on surfaces of the negative electrode active
electrode. Consequently, the battery voltage of the aqueous material and the negative electrode current collector. When
lithium ion battery reaches only about 2 V , and the energy the negative electrode electro -conductive agent is included ,
density is lower than that of the nonaqueous lithium ion it is preferable that each of the negative electrode active
battery . 10 material, the negative electrode current collector, and the
When a negative electrode material having a low operat negative electrode electro - conductive agent has a covering
ing potential such as Li Ti 012 is used in order to increase layer formed on at least a portion of the surface . Thus,
the battery voltage of the aqueous lithium ion battery, the electrolysis of water at each reaction field can be suppressed
hydrogen generation on the negative electrode becomes by the covering layer. It is a matter of course that , in an
significant, and not only does the safety become reduced , but 15 nonaqueous battery including no aqueous solvent, the water
also, the battery characteristics may be reduced due to the electrolysis is not required to be paid attention to , and
generated hydrogen . attention may be paid to side reaction between an active
Hereinafter, embodiments will be described with refer material and a nonaqueous electrolyte .
ence to the drawings . According to embodiments, since the water electrolysis at
The lithium secondary battery according to embodiments 20 the negative electrode can be suppressed , even when a
includes a positive electrode , a negative electrode, and an battery using an electrolytic solution , including an aqueous
electrolytic solution . The negative electrode includes a cur solvent, and a negative electrode active material operating at
rent collector and a negative electrode active material low potential is operated , hydrogen generation can be sup
including titanium -containing oxide. At least one of the pressed . As a result, since self-discharge in a lithium ion
current collector and the negative electrode active material 25 secondary battery can be suppressed , charge -and -discharge
has on at least a portion of its surface a covering layer efficiency and charge -and -discharge cycle life of the battery
including at least one kind of element selected from the can be enhanced . Accordingly , according to the configura
group consisting of Zn, In , Sn , Pb, Hg, Cu , Cd , Ag, and Bi. tion of the embodiment, safety is enhanced by using an
The electrolytic solution includes an aqueous solvent and an aqueous solvent in an electrolytic solution , and , at the same
electrolyte . 30 time, a lithium secondary battery exhibiting excellent
In a lithium ion secondary battery using an aqueous charge -and-discharge efficiency and cycle life can be
solvent, a current collector (negative electrode current col achieved .
lector) and an active material (negative electrode active Herein after, each feature of the lithium secondary battery
material) within the negative electrode may serve as a according to embodiments will be described .
reaction field for hydrogen generation . When the negative 35 1 ) Negative Electrode
electrode includes an electro -conductive agent (negative A negative electrode includes a currentcollector (negative
electrode electro -conductive agent), hydrogen may also be electrode current collector) and a negative electrode mixed
generated in the negative electrode electro -conductive agent. materials layer ( negative electrode active material- contain
According to the above constitution , for each of the current ing layer) including a negative electrode active material.
collector and /or particles of the active material serving as the 40 The current collector may include at least one kind of
reaction field for hydrogen generation at the negative elec metal selected from the group consisting of aluminum ,
trode , hydrogen generation can be suppressed by disposing copper, zinc, nickel, titanium , and iron . Among them , the
a film ( covering layer ) with low catalyzing activity on at current collector preferably includes zinc with high hydro
least a portion of the surface . When the negative electrode gen overvoltage . The current collector may include one of
includes the electro - conductive agent, hydrogen generation 45 those metals, or include two or more kinds of those metals.
can be suppressed by disposing a film with low catalyzing For example , alloy such as stainless steel may be used . The
activity on a portion of a surface of the particles of the current collector may be a substrate including those metals,
electro - conductive agent. for example . The substrate as the current collector is, for
With regard to a nonaqueous electrolyte battery using a example , a metal foil formed of those metals. Further, the
nonaqueous solvent such as an organic solvent, as a solvent 50 substrate as the current collector is , for example , a foil
of an electrolytic solution , rather than an aqueous solvent, formed of alloy including those metals.
there have been reported examples aiming to obtain effects Examples of the shape of the current collector include a
different from suppression of hydrogen generation , in which mesh shape and a porous shape in addition to a foil shape .
a covering layer including , for example , zinc ( Zn ) or copper In order to enhance energy density and output, the shape of
( Cu) is formed on a surface of negative electrode active 55 a foil having a small volume and a large surface area is
material particles. For example , when an alloy - based mate preferable.
rial such as a silicon -based material or a tin -based material It is preferable that a film such as a carbon -containing
is used as an active material, a shape change such as volume film , a polymer film , and an oxide film is formed on at least
expansion of the active material accompanying charge and a portion of a surface of a current collector. If such a film
discharge and fracturing of the active material accompany- 60 exists on the surface of the current collector , an effect of
ing the shape change can be suppressed by covering a further suppressing hydrogen generation can be expected .
surface of the active material with a layer of a metal Further, such a film can cover a substrate including the
material. In addition , production of lithium salt on the above-described metals in the current collector, for example.
surface of the activematerial that may cause short-circuiting The negative electrode active material includes a tita
can be suppressed . 65 nium -containing oxide . Examples of the titanium -containing
As described above , in the negative electrode included in oxide may include an oxide of titanium , a lithium - titanium
the lithium ion secondary battery using the aqueous solvent, oxide , a niobium -titanium oxide , and a sodium - niobium
 US 10,727,540 B2
19 20
titanium oxide . The Li insertion potential of the titanium nylidene fluoride (PVDF ), fluororubber , an acrylic resin , and
containing oxide is desirably in a range of 1 V (vs. Li/Li+) cellulose such as carboxymethyl cellulose .
to 3 V (vs. Li/Li +). The negative electrode active material With respect to the mixing ratio of the negative electrode
may include one of the titanium -containing oxides , or 5 active material, the electro -conductive agent, and the binder
in the negative electrode mixed -materials layer, it is prefer
include two or more of the titanium -containing oxides.
Examples of the oxide of titanium may include an oxide able that isthewithin proportion of the negative electrode active
of titanium having a monoclinic structure, an oxide of material a range of 30 % by weight to 96 % by
titanium having a rutile structure , and an oxide of titanium weight , the proportion of the negative electrode electro
having an anatase structure. For the oxide of titanium having conductive agent is within a range of 2 % by weight to 60 %
each crystal structure , the composition before charging can 10 by weight, and the proportion of the binder is within a range
be represented by TiO2, and the composition after charging of the
2 % by weight to 30 % by weight. When the proportion of
electro -conductive agent is less than 2 % by weight, the
can be represented by Li, TiO2, wherein x is Osxsl . The current collecting performance of the negative electrode
structure before charging for the oxide of titanium having mixed -materials layer is reduced , and consequently , the high
the monoclinic structure can be represented by Ti, ( B ). 15 current performance of the battery may be reduced . When
Examples of the lithium -titanium oxide include a lithium the proportion of the binder is less than 2 % by weight, the
titanium oxide having a spinel structure (for example , the binding between the negative electrode mixed -materials
general formula : Li4 +xTi 012 wherein x is -1sx53) , a layer and the negative electrode current collector is reduced ,
lithium - titanium oxide having a ramsdellite structure ( for and consequently, the cycle performance may be reduced .
example , Liz Tigo , wherein -1sx53), Li +xTi_04 wherein 20 On the other hand, from the perspective of obtaining a high
Osxsi, Li1.1 +4T11.804 wherein Osxsl, Li1.07 +xT11.8604 capacity , the electro -conductive agent and the binder are
wherein Osxsl, and Liz TiO2 wherein 0 < xsl), and the like . preferably included in proportions of 60 % by weight or less
The lithium - titanium oxide includes, for example , a and 30 % by weight or less, respectively .
lithium - titanium composite oxide in which a dopant is In the embodiments , at least one of the negative electrode
introduced into the above lithium -titanium oxide having the 25 current collector, the negative electrode active material, and
spinel structure or the ramsdellite structure . the electro -conductive agenthas, on at least a portion of the
Examples of the niobium - titanium oxide include oxides surface , a covering layer including at least one kind selected
represented by Li, TiM ,Nb2+80770 (Osas5 , Osbs0.3 , from the group consisting of Zn , In , Sn , Pb , Hg, Cu , Cd , Ag,
Osß < 0.3, Osos0.3 , and M is at least one element selected and Bi.Among them , a covering layer including one or more
from the group consisting of Fe, V, Mo, and Ta ) and the 30 kinds of Zn , In , Sn , Pb , and Hg is preferable from the
general formula Ti - Mx+„ Nb2-07-y (Osxs1, Osy < 1, and M viewpoint of suppressing electrolysis of water.
includes at least one selected from the group consisting of The covering layer has a thickness ( layer thickness) of 2
Mg, Fe Ni, Co W , Ta and Mo). nm or more to 5 um or less , for example . If the thickness of
Examples of the sodium -niobium -titanium oxide include the covering layer is 100 nm or less , good Li diffusibility can
an orthorhombic Na- including niobium -titanium -composite 35 be maintained in voids existing in an electrode or on an
oxide represented by the general formula active material surface , and therefore , it is preferable . The
Liz ,Naz - M1, Ti6-1--Nb,M2,014 +6 ( Osvs4 , O < w < 2 , covering layer may be a film having a film thickness in the
Osx < 2 , 0 < y < 6 , Osz < 3 , y + z < 6 , -0.5sds0.5 , M1 includes at above range and formed on the surface of the negative
least one element selected from the group consisting of Cs, electrode current collector, and /or the negative electrode
K , Sr, Ba, and Ca, and M2 includes at least one element 40 active material, and /or the electro - conductive agent.
selected from Zr, Sn , V , Ta , Mo, W , Fe, Co, Mn, and Al). The covering layer may include a metal phase formed of
The negative electrode active material is included in the at least one kind of element selected from the group con
negative electrodematerial layer , for example, in the form of sisting of Zn, In , Sn , Pb , Hg, Cu , Cd , Ag, and Bi. The
particles . The negative electrode active material particle covering layer may further include an alloy phase including
may be singular primary particles, secondary particles in 45 those elements . The covering layermay furthermore include
which each of the secondary particles include aggregated oxide phases and /or hydroxide phases of those elements .
primary particles, or a mixture of singular primary particles The entire covering layer may be constituted of any one of
and secondary particles. The shape of the particles is not those phases , or two or more phases may be mixed in the
particularly limited and , for example , may be a spherical covering layer. Since the catalytic activity of an oxide is low
shape, an elliptic shape , a flat shape , a fiber shape, or the 50 with respect to a hydrogen generation reaction , it is more
like . preferable that the covering layer includes the oxide phase .
The negative electrode mixed -materials layer can be The covering layer may cover the entire surface of each
disposed on one surface or both of reverse surfaces of the of the negative electrode current collector, the negative
negative electrode current collector. The negative electrode electrode active material particles, and electro -conductive
mixed-materials layer may further include an electro - con- 55 agent particles or may partially cover each of them . Even in
ductive agent and a binder , in addition to the negative a case where the covering layers are scattered on each
electrode active material. surface , rather than covering the entire surface , an effect of
Examples of the electro -conductive agent may include suppressing a side reaction of hydrogen generation can be
carbonaceous substances such as acetylene black , carbon expected . For each of the negative electrode current collec
black , graphite, carbon nanofiber, and carbon nanotube. The 60 tor, the negative electrode active material particles, and
carbonaceous substances may be used alone or as a mixture electro -conductive agent particles , the cover ratio of the
of plural carbonaceous substances . The electro - conductive surface area by the covering layer is preferably 10 % or more
agent may be included in the negative electrode material to 100 % or less . Each cover ratio is more preferably 60 % or
layer in the form of particles. more . For each of them , it is more preferable that the entire
The binder binds the active material, the electro -conduc- 65 surface is uniformly covered.
tive agent, and the current collector. Examples of the binder From the viewpoint of suppressing self - discharge , among
may include polytetrafluoroethylene (PTFE ), polyvi the negative electrode current collector, the negative elec
 US 10,727,540 B2
21 22
trode activematerial particles, and electro -conductive agent electrode of an oxide of titanium is operated . When a metal
particles, it is most effective that the negative electrode formed of an element that becomes a constituent element of
active material particles include a covering layer . In the case a covering layer is included in a current collector, a covering
where the negative electrode active material does not layer can be formed using elution of the element from the
include a covering layer on the surface, when charging a 5 current collector and reprecipitation of the element.
battery, an oxidation -reduction reaction may occur between In a case of using the negative electrode active material
an aqueous solvent and the active material. Due to this whose potential is relatively low , having a potential of an
oxidation- reduction reaction, electrons are accepted and insertion and extraction reaction of lithium of less than -1.0
donated within the battery without passing through an
external circuit. Due to this , the active material is dis- 10 asV (described
vs. SCE ) and more preferably -1.1 V or less ( vs. SCE ),
above, when charge and discharge are per
charged . When the active material particles include a cov formed in the operating potential range of the negative
ering layer, self-discharge can be effectively suppressed . electrode active material , a potential significantly lower than
In addition to the negative electrode active material -0.76 V , which is an oxidation -reduction equilibrium poten
particles, it is more preferable that the negative electrode
current collector and the electro -conductive agent particles 15 tial of zinc , can be applied to a negative electrode, for
each include a covering layer on the surface . This is, as example . Thus , by virtue of the use of the negative electrode
described above, because during charging, electrolysis of active material in which the insertion /extraction potential of
water occurs on a surface of a member having electric Li is low , as described above , the formation of a covering
conductivity , such as a current collector and an electro layer by electrodeposition can be achieved by usual charge
conductive agent. When a covering layer is disposed on each 20 and discharge. On the other hand , in the case of using a
surface of those members , the side reaction can be effec compound such as a vanadium -based active material, in
tively suppressed . which the potential of the insertion and desorption reaction
The covering layer may be formed by applying electrode of Li is -1.0 V or more ( vs. SCE ), as a negative electrode
position to a negative electrode produced by, for example , a active material , even if charge and discharge are performed
method described later. The electrodeposition may be 25 in the operating range , a covering layer cannot be formed .
applied to a negative electrode alone by using a plating bath , By virtue of the use of the electrodeposition as described
or may be applied to a negative electrode incorporated into above , a covering layer can be formed on a surface of each
a battery by using a reaction of an additive included in an of a negative electrode active material, a negative electrode
electrolytic solution , for example . In either case , the cover current collector, and an electro -conductive agent.
ing is applied by applying current at a predetermined poten- 30 When a covering layer is formed respectively on the
tial or less at which a constituent element precipitates in a surface of each of the negative electrode active material, the
solution having the constituent element of a covering layer negative electrode current collector, and the electro -conduc
dissolved therein . tive agent, one example is a process in which each member
When a covering layer is formed using a plating bath , is respectively mixed by a wet process with a compound
plating treatment is applied to a negative electrode under the 35 including the constituent element of the covering layer , and
following conditions, for example , whereby plating includ baked . As a specific example, a case where a film of zinc
ing a zinc metal phase is formed on each surface of a oxide is formed on a lithium titanate powder as a negative
negative electrode current collector, a negative electrode electrode active material is shown as follows. As a matter of
active material, and an electro -conductive agent in the course , materials to be used , conditions, and so on can be
negative electrode . 40 suitably changed according to an active material used in a
ZnCl2 : 30 to 100 g/L negative electrode , a composition of a covering layer, a
Zn : 15 to 50 g /L member to be covered , the form of the member, and so on .
NH4Cl: 100 to 150 g /L First, a lithium titanate powder is immersed in a zinc
PH : 4.5 to 6.0 sulfate aqueous solution of 0.1 M , and while stirring, a
Bath Temperature : 20 to 35º C. 45 sodium carbonate aqueous solution of 0.1 M is added - in
Current Density : 1 to 10 A / dm² dropwise . A precipitate of a mixture of a white basic zinc
Here, although the example in which a covering layer carbonate and the lithium titanate powder thus obtained is
including zinc is formed is shown as a specific example, washed with water and subsequently dried . After that, the
conditions of a plating bath used for plating treatment, washed mixed powder is baked at a temperature of approxi
treatment conditions , and so on can be suitably changed 50 mately 140 ° C. to 350 ° C. Thereby, a powder of lithium
according to the composition of a covering layer to be titanate whose surface is covered with zinc oxide can be
formed . It is preferable from the viewpoint of uniform produced . Each surface ofelectro -conductive agent particles
electrodeposition that additives such as citric acid , saccha and a current collector can be covered by a similar method .
rin , and polyvinyl alcohol are added to the plating bath . A film may be formed by a mechanochemical method
When those additives are added , unevenness of electrode- 55 with respect to each member. For example , a powder of zinc
position can be suppressed , and a uniform covering layer can and lithium titanate particles are put into a ball mill and
be obtained . mixed with acetone , ethanol, and the like as dispersion
It is preferable from the viewpoint of simplifying pro media . Thereby , a zinc film is formed on a lithium titanate
cesses that a compound including a constituent element (one surface by physical pressure . This method can also be
or more selected from the group consisting of Zn , In , Sn , Pb , 60 applied to electro -conductive agentparticles . Here , although
Hg, Cu , Cd, Ag, and Bi, etc.) is added to an electrolytic the method of forming a covering layer including zinc with
solution , whereby a covering layer is formed making use of respect to the particles of lithium titanate as a negative
a current during charging of a battery . For example, when a electrode active material has been described as a specific
chloride or a sulfate of the above constituent element is example , materials to be used , conditions, and so on can be
added to an electrolytic solution at a ratio of 1 mM or more 65 suitably changed according to an active material used in a
to 100 mM or less, a covering layer can be formed by charge negative electrode, the composition of the covering layer, a
and discharge in a potential range in which a negative member to be covered , the form of the member, and so on .
 US 10,727,540 B2
23 24
The negative electrode can be produced , for example, by 2 ) Positive Electrode
the following method . First, the negative electrode active The positive electrode may include a positive electrode
material , the electro -conductive agent, and the binder are current collector and a positive electrode mixed -materials
suspended in a solvent to prepare a slurry. The slurry is layer (positive electrode active material- including layer).
coated onto one surface or both of reverse surfaces of the 5 onTheone positive electrode mixed -materials layermay be formed
negative electrode current collector. The coat applied onto electrodesurface or both of reverse surfaces of the positive
the negative electrode current collector is dried to form a materials current collector. The positive electrode mixed
negative electrode mixed -materials layer. After that, the material, and optionallyinclude
layer may a positive electrode active
an electro - conductive agent and a
negative electrode current collector and the negative elec binder.
trode mixed -materials layer formed thereon are subjected to 10 As the positive electrode active material, for example,
pressing. Alternatively, the negative electrode active mate compounds capable of having lithium inserted and extracted
rial, the electro -conductive agent, and the binder may be may be used . The positive electrode active material may
formed into pellets, and used as the negative electrode include, for example , a lithium -manganese composite oxide,
mixed -materials layer. 15
a lithium -nickel composite oxide, a lithium - cobalt -alumi
When the negative electrode is thus produced , a negative num composite oxide , a lithium -nickel-cobalt-manganese
composite oxide , a spinel-type lithium -manganese -nickel
electrode active material, an electro -conductive agent, and a composite oxide , a lithium -manganese -cobalt composite
negative electrode current collector each formed with a oxide, a lithium iron oxide, a lithium fluorinated iron sulfate ,
covering layer, for example ,by the above -described method a phosphate compound having an olivine crystal structure
may be used . Alternatively, after the negative electrode is 20 (for example, Li FePO4 wherein Osxsl, or Li,MnPO4
produced using those members without covering layer, a wherein Osxsl), and the like . The phosphate compound
covering layer may be formed on the obtained negative having the olivine crystal structure has excellent thermal
electrode, by the above - described method. stability .
< Analysis of Covering Layer> Examples of the positive electrode active material with
The composition and thickness (layer thickness ) of a 25 which a high positive electrode potential can be obtained are
covering layer can be analyzed by observation using a described below . Examples include lithium -manganese
scanning transmission electron microscope (STEM ), for composite oxides such as Li Mn204 (0 < xsl), or Li MnO2
example. As one example of STEM , HD2300A manufac (0 < xsl ); a lithium -nickel-aluminum composite oxide such
tured by Hitachi High - Technologies Corporation can be as Li,Ni1_ , A1,02 (0 < xsl and ( < ysl ); lithium -cobalt - com
used . The thickness of the covering layer is measured at an 30 posite oxides such as Li, C002 (0 < xsl); lithium -nickel
acceleration voltage of 200 kV, for example , and can be cobalt composite oxides such as Li, Nil-y- Co,Mn_02
quantified from a difference in image contrast between a (composite 0 < xsl, O < ysl, and Oszsl); lithium -manganese -cobalt
oxides such as Li,Mn, C0-0 , (0 <xsl and
targetmember including the covering layer (current collec O < ysl ); spinel - type lithium -manganese- nickel composite
particles) and the covering layer. The composition of the phosphorus oxidesMn2-
tor , active material particles, or electro -conductive agent 35 oxides such as Li „Ni,04(0< xsl and ( < y <2 ); lithium
having an olivine structure such as
covering layer is measured at an acceleration voltage of 200 Li, FePO4 (0 < xsl), Li,Fe -Mn
KV, for example , and can be quantified by energy dispersive Li CoPO4 (0 < xsl ); fluorinated, P04iron(0 < xsl and Osysl), or
sulfates ( such as
X -ray spectrometry (EDS) analysis . When measurement is Li,FeSO4F wherein (0 < xsl )).
performed by STEM , a measurement sample ( each member 40 One kind of the positive electrode activematerials may be
including a covering layer) is first made into thin pieces used alone , or two or more kindsmay be used . The positive
having a thickness of 0.1 um by focused ion beam (FIB ) electrode active material preferably includes at least one
processing , and in order to protect the outermost surface , a compound selected from the group consisting of LiFePO4,
C film and a W film are formed . A sample thus processed is LiMn204, and LiCo02, among the compounds described
observed at an observation magnification of 200,000 times. 45 above . When these materials are used , the oxidative decom
At this time, a difference in composition between a covering position of the aqueous solvent can be suppressed because
layer and a member (current collector, active material par the operating potential does not become too high .
ticles , or electro -conductive agentparticles ) is obtained as an The electro - conductive agent, which may be included in
image contrast, and the thickness of the covering layer can the positive electrode mixed -materials layer, includes the
be quantified . The composition of the covering layer can be 50 same electro -conductive agent as those thatmay be included
analyzed by EDS . For example , when the covering layer has in the negative electrodemixed -materials layer. Examples of
a large thickness of 100 nm or more, a similar observation the electro - conductive agent, accordingly , include carbona
is performed by suitably adjusting the magnification accord ceous substances such as acetylene black , carbon black ,
ing to a state ofmeasurement target such that observation is graphite , carbon nanofiber and carbon nanotube . The car
easily performed 55 bonaceous substances may be used alone or as a mixture of
The cover ratio of a covering layer on a surface of each plural carbonaceous substances .
member can be quantified by EDS analysis . The cover ratio The binder binds the active material , the electro -conduc
in a current collector is quantified from an abundance ratio tive agent, and the current collector in the positive electrode
between a current collector (for example,metal constituting mixed -materials layer, in a similar manner as with the
a foil) and the constituent elements of the covering layer. 60 negative electrode mixed -materials layer. The binder, which
Similarly, the cover ratio of an electro -conductive agent is may be included in the positive electrode mixed -materials
quantified from an abundance ratio between the electro layer, includes the samebinder as those thatmay be included
conductive agent (for example, a carbonaceous material) in the negative electrodemixed -materials layer. Examples of
and the covering layer, and the cover ratio of an active the binder, accordingly , include polytetrafluoroethylene
material is quantified from an abundance ratio between the 65 (PTFE ), polyvinylidene fluoride (PVDF ), fluororubber , an
constituent elements of the active material and the constitu acrylic resin , cellulose such as carboxymethyl cellulose , and
ent elements of the covering layer. the like.
 US 10,727,540 B2
25 26
With respect to the mixing ratio of the positive electrode it is possible to obtain an electrolytic solution in which the
active material, the electro -conductive agent, and the binder anions have a high concentration of 1 M to 10 M and the Li
in the positive electrode mixed -materials layer, it is prefer ion diffusion is good .
able that the proportion of the positive electrode active An electrolytic solution including NO3 and /or Cl- can be
material is within a range of 30 % by weight to 95 % by 5 used in a wide anion concentration range of approximately
weight, the proportion of the electro -conductive agent is from 0.1 M to 10 M for each of NO3- and Cl-. It is
within a range of 3 % by weight to 60 % by weight, and the preferable from the viewpoint of ion conductivity that the
proportion of the binder is within a range of 2 % by weight anions have a high concentration of from 3 M to 9 M. It is
to 30 % by weight. When the mixing ratio of the electro more preferable that the anion concentration of the electro
conductive agent is 3 % by weight or more, the electric 10 lyticAnsolution including NO3including
and Cl-LiSO4
is from and8 M/ortoSO4
9 M.
2
conductivity of the positive electrode can be secured . When can beelectrolytic solution
used in the anion concentration range of approxi
the mixing ratio of the electro -conductive agent is 18 % by mately from 0.05 M to 2.5 M for each of LiS04 and SO42
weight or less, the decomposition of the electrolytic solution It is preferable from the viewpoint of ion conductivity that
onat athe surface of the electro -conductive agent during storage
high temperature can be reduced . When the mixing ratio
15 the anions have a high concentration of from 1.5 M to 2.5 M.
It is desirable that the OH- concentration in an electrolytic
of the binder is 2 % by weight or more , sufficient electrode solution is from 10-14 M to 0.1 M.
strength can be obtained . When the mixing ratio of the An electrolytic solution including BOB can be used in
binder is 30 % by weight or less, the mixed amount of the the anion concentration range of approximately from 0.1 M
binder, which is an insulating material , within the positive 20 to 5 M. However, since BOB- is hydrolyzed , some are
electrode is decreased , thus the internal resistance can be present as oxalate ions in the electrolytic solution. Consid
decreased . ering stability and solubility after decomposition , the anion
In the positive electrode current collector, as in the concentration is preferably from 0.1 M to 1.0 M.
negative electrode current collector, a film such as a carbon An electrolytic solution including TFSI and /or FSI- can
containing film , a polymer film , and an oxide film may be 25 be used in the anion concentration range of approximately
formed . When the positive electrode current collector from 0.1 M to 21 M for each of TFSI- and FSI- . It is
includes such a film , corrosion of the positive electrode preferable from the viewpoint of suppressing a side reaction
current collector due to an aqueous solvent in an electrolytic that the anions have a concentration of from 15 M to 21 M.
solution can be suppressed , and thus it is preferable . The electrolytic solution may include an additive, as a raw
The positive electrode may be produced by the following 30 material used when a covering layer included in a negative
method . First the positive electrode active material, the electrode is formed by the above -described electrodeposi
electro - conductive agent, and the binder are dispersed in a tion according to charge and discharge of a battery. As the
solvent to prepare a slurry. hen , the slurry is coated on ad ive, a chloride , sulfate, or ate, including at least one
one surface or both of reverse surfaces of the positive selected from the group consisting of Zn , In , Sn , Pb , Hg, Cu ,
electrode current collector. The coat applied onto the posi- 35 Cd ,Ag, and Bimay be included . Particularly , it is preferable
tive electrode current collector is dried to form the positive from the viewpoint of suppressing electrolysis of water that
electrode mixed -materials layer. After that, the positive a covering layer is formed using an additive including at
electrode current collector and the positive electrode mixed least one selected from the group consisting of Zn , In, Pb ,
materials layer formed thereon are pressed . Alternatively, and Hg having a high hydrogen overvoltage. The concen
the positive electrode active material, the electro -conductive 40tration of the above additive is preferably 2 mM or more to
agent, and the binder may be formed into pellets , and used 50 mM or less. The concentration of the additive is more
as the positive electrode mixed -materials layer . preferably 5 mM or more . If the concentration is 2 mM or
3 ) Electrolytic Solution more, the formation of a covering layer by charge and
An electrolytic solution includes an aqueous solvent and discharge is promoted. If the concentration is 50 mM or less,
an electrolyte. The electrolytic solution includes at least one 45 excessive electrodeposition can be suppressed .
kind of anion selected from the group consisting of NO3 , From the viewpoint of stabilizing formation of a surface
Cl- , LiSo . , SO 2-, OH-, TFSI- {bis(trifluoromethanesul film by electrodeposition , saccharin , citric acid , boric acid ,
fonyl) imide ion ; [N (SO2CF3) 21-}, FSI- ( lithium bis ( fluoro polyethylene glycol, and the like may be added to an
sulfonyl)imide ion ; [N (SO , F )2]" }, and BOB- {bisoxalate electrolytic solution. Due to adsorption of their molecules to
borate ion ; [B (C204)21- }. One of these anions may be 50 a surface of the target onto which a covering layer is to be
included in the electrolytic solution , or two or more of these formed (negative electrode current collector and/or negative
anions may be included . electrode active material particles and /or electro -conductive
As an aqueous solvent, a solution including water can be agent particles ), or an interface complex formation reaction
used. Here , the solution including water may be pure water with metal ions of an element that becomes the constituent
or a mixed solution or a mixed solvent of water and 55 element of the covering layer, an effect of suppressing
materials other than water. excessive covering layer formation reaction can be
As an electrolyte , a second electrolyte that dissociates expected
when dissolved in an aqueous solvent to generate the anions The pH ofan electrolytic solution is preferably 0 or more
may be used . In particular, lithium salt that dissociates into and 13 or less . If pH is less than 0 , since the electrolytic
Li ions and the anions is preferable. Examples of such 60 solution is strongly acidic , decomposition of an active
lithium salt include LiNO3, LiCl, Li2SO4, LiOH , LITFSI material and degradation of a current collector tend to
[ lithium bis(trifluoromethanesulfonyl) imide; progress. If pH is more than 13 , since oxygen generation
LiN (SO , CF3)2 ], LiFSI [ lithium bis (fluorosulfonyl)imide ; overvoltage in a positive electrode is reduced ,electrolysis of
LiN ( SO F )2], and LiBOB [ lithium bisoxalate borate ; LiB an aqueous solvent tends to progress.
(C ,02), 65 A solute, that is, an electrolyte in an electrolytic solution
Lithium salt that dissociates into Li ions and the anions can be qualitatively detected and quantified by an ion
has a relatively high solubility in an aqueous solvent. Thus, chromatography method , for example . Since the sensitivity
 US 10,727,540 B2
27 28
of the ion chromatography method is high , the ion chroma 7 ) Container Member
tography method is particularly preferable as an analytical As the container member, a bag - shaped container made of
method . a laminate film or a metal container may be used . The shape
Examples of specific measuring conditions of qualitative of the container member may include , for example, a
and quantitative analysis of a solute, included in an electro- 5 flat- type, a square-type, a cylindrical- type , a coin -type, a
lytic solution , using the ion chromatography method are button -type , a sheet-type , a laminate -type , and the like . Of
shown as follows: course , any appropriate container member can be used
System : Prominence HIC -SP depending on the use of the lithium secondary battery. For
Analysis column: Shim -pack IC -SA3 example ,when the lithium secondary battery is loaded on a
Guard column: Shim -pack IC - SA3(G ) 10 portable electronic device, a container member for a small
Eluent: 3.6 mmol/L sodium carbonate aqueous solution sized battery can be used . When the lithium secondary
Flow rate : 0.8 mL /min battery is loaded on vehicles such as two-wheel to four
Column temperature : 45 ° C. wheel automobiles, a container member for a large scale
Injection amount: 50 uL
battery can be used .
Detection : electrical conductivity
15 As the laminate film , for example, a multilayer film which
4 ) Electrode Terminal
includes resin layers and a metal layer disposed between the
resin layers may be used . The metal layer is preferably an
The electrode terminal may include, for example , an aluminum foil or aluminum alloy foil in order to reduce the
external terminal and an internal terminal. The external weight. As the resin layer, for example , a polymer material
terminal is , for example, an electrode lead . Alternatively, an 20 such as polypropylene (PP ), polyethylene (PE ), nylon , or
electrically conductive container member such as a metal polyethylene terephthalate (PET)may be used . The laminate
can may be used as the external terminal, as described film can be sealed and formed into a shape of the container
below . The internal terminal includes, for example , an member. The laminate film has preferably a thickness of 0.5
electrode tab . The shape of the internal terminal is not mm or less, more preferably 0.2 mm or less.
particularly limited , and may include, for example, a belt 25 The metal container is preferably formed from , for
shape, a disk shape , a washer shape, a spiral shape , a example , at least one metal selected from the group con
corrugated plate shape, and the like. sisting of aluminum , zinc, titanium , and iron , or an alloy of
The electrode terminal is preferably formed from at least the metal. Specific examples of the alloy include aluminum
onemetal selected from the group consisting of aluminum , alloy and stainless steel. The metal container preferably has
zinc, titanium , and iron , or from an alloy thereof. Examples 30 a wall thickness of 0.5 mm or less, more preferably 0.2 mm
of the alloy include aluminum alloy or stainless steel. As the or less.
material for the internal terminal, a metal capable of sup When the metal container is used as the container mem
pressing the electrolysis of the aqueous solvent is desirable .
ber, the metal container can also be used as the electrode
For example , it is preferable that the positive electrode terminal ( the external terminal) .
internal terminal is made of titanium , and the negative 35 Examples of the lithium secondary battery according to
electrode internal terminal is made of zinc . the embodiment is explained below , with reference to FIG .
The internal terminal may get into contact with the 9 to FIG . 11 .
electrolytic solution inside the battery. For that reason , it is FIG . 9 shows one example of a lithium secondary battery
desirable that the surface of the internal terminal is protected using a coin -type metal container.
with an insulating resin , thereby suppressing the electrolysis 40 As shown in FIG . 9 , a coin -type lithium secondary battery
of the aqueous solvent. As the insulating resin , for example , has a structure in which a negative electrode 106 , a separator
a polymer material such as polypropylene (PP), polyethyl 105 , a gasket 108, a positive electrode 102 , a spacer 104 , a
ene (PE ), nylon , and polyethylene terephthalate (PET) may washer 103, and a positive electrode can 101 are sequen
be used . tially stacked in a negative electrode can 107. In the negative
The electrode terminal is used for electrically connecting, 45 electrode can 107, an electrolytic solution (not shown) is
for example, an external circuit to the inside of the battery housed . The electrolytic solution may be housed within the
through the electrode terminal. By connecting the external lithium secondary battery in a state in which the negative
circuit to the electrode terminal , supplying of electric current electrode 106 , the separator 105 and /or the positive electrode
to the external circuit becomespossible. Alternatively, in the 102 are impregnated with the electrolytic solution . The
case where plural batteries are electrically connected in 50 electrolytic solution can also be housed within the lithium
series or in parallel, the electrode terminals are electrically secondary battery in a state in which the solution is filled in
connected among the plural batteries. a space within the battery .
5 ) Separator Here , the negative electrode 106 is, for example , a disk
As the separator, for example , a porous film or a synthetic shaped negative electrode obtained by punching a negativ
resin non -woven fabric may be used which is formed from 55 electrode , produced as described above, into a round shape .
a material such as polyethylene (PE ), polypropylene (PP ), The positive electrode 102 is, for example , a disk -shaped
cellulose, glass fiber, or polyvinylidene fluoride ( PVDF ). Of positive electrode obtained by punching a positive electrode ,
these , cellulose is preferable because of its excellent ability produced as described above, into a round shape .
to hold liquids and Li diffusibility. The spacer 104 and the washer 103 function as a positive
6 ) Gasket 60 electrode internal terminal to secure the electrical conduc
As the gasket, for example , a polymer material such as tivity between the positive electrode 102 and the positive
polypropylene (PP ), polyethylene (PE ), nylon , polyethylene electrode can 101. When the washer 103 is a waved washer,
terephthalate (PET), or polyimidemay be used . By using the as shown in the drawing , the contact between the washer 103
polymer material as the gasket, not only can the air-tightness and the spacer 104 or the positive electrode can 101 can be
of the battery interior be improved , but also , short -circuiting 65 made more definite , and the electrical conductivity can be
between the positive electrode and the negative electrode further secured . In FIG . 9 , the spacer 104 and the washer 103
can be prevented . ( the waved washer ) are shown as the positive electrode
 US 10,727,540 B2
29 30
internal terminal of the coin -type lithium secondary battery, A positive electrode gasket 118 and a negative electrode
but the positive electrode internal terminal may be a single gasket 119 are respectively disposed on the inner circum
member or pluralmembers in greater number, and the shape ferential surface of each outlet of the sealing plate 121, in
thereof is not limited to that shown in the drawing . order to avoid short-circuiting due to contact of the sealing
The negative electrode can 107 is a metal can serving as 5 plate 121 with the positive electrode conductive lead 116
a container member for the coin -type lithium secondary and the negative electrode conductive lead 117. Further
battery, and also functions as the negative electrode terminal more , by disposing the positive electrode gasket 118 and the
( the external terminal ). Similarly, the positive electrode can negative electrode gasket 119 , the air-tightness of the
101 is a metal can serving as a container member, and also square -type lithium secondary battery can be maintained .
functions as the positive electrode terminal ( the external 10 A control valve 122 (a safety valve) is disposed on the seal
terminal). The center part of the positive electrode can 101 plate 121. When the internal pressure within the battery is
is open in order to release gas generated within the battery increased due to gas generation caused by the electrolysis of
(not shown). During production of the coin -type lithium the aqueous solvent, the generated gas can be released to the
secondary battery , the electrolytic solution can be put into outside through the control valve 122. As the control valve
the positive electrode can 101 through the opening . By 15 122 , for example, a return type control valve ,which operates
adjusting the amount of electrolytic solution when putting when an internal pressure becomes higher than a pre
the electrolytic solution in , the leakage of the electrolytic determined value and functions as a sealing plug when the
solution to the outside of the battery can be prevented . For internal pressure is reduced , may be used . Alternatively, a
example , if the amount of the electrolytic solution put in is non -return type control valve, which does not recover its
adjusted to about 100 ul, the electrolytic solution may 20 function as the sealing plug once it is operated , may also be
become impregnated in the negative electrode 106 , the used . In FIG . 10 , the control valve 122 is disposed at the
separator 105 , and the positive electrode 102 as described center of the sealing plate 121, but the control valve 122 may
above, and the solution may be held there. The leakage of the be located at the end of the sealing plate 121. The control
electrolytic solution can also be prevented , for example , by valve 122 may be omitted .
using a thick separator 105 having a thickness of about 0.1 25 According to the fourth embodiment described above ,
to 0.5 um . there can be provided a lithium secondary battery that has
One example of a lithium secondary battery using a high safety because an electrolytic solution including an
square -type metal container is shown in FIG . 10 and FIG . aqueous solvent is used , and excellent in charge - and -dis
11. charge efficiency and charge-and -discharge cycle life
The electrode group 113 is housed in a rectangular -tube- 30 because self -discharge is suppressed .
shaped metal container 120. The electrode group 113 has, for
example , a structure where plural positive electrodes 110 , Fifth Embodiment
negative electrodes 111, and separators 112 are stacked in
order of the positive electrode 110 , the separator 112, the According to a fifth embodiment, a battery module
negative electrode 111 and the separator 112. Alternatively , 35 including a lithium secondary battery as a unit cell is
the electrode group 113 may also have a structure in which provided . As the lithium secondary battery , a lithium sec
the positive electrode 110 , the negative electrode 111 , and ondary battery of the fourth embodiment may be used .
the separator 112 disposed therebetween are spirally wound Examples of the battery module include a battery module
in a manner such that a flat shape is obtained . Regardless of including unit cells as structural units , each being electri
the structure of the electrode group 113, it is desirable that 40 cally connected to each other in series or in parallel, a battery
the separator 112 is disposed as the outermost layer of the module including a unit structured by plural unit cells that
electrode group 113 in order to avoid contact between the are electrically connected in series or a unit structured by
electrodes and the metal container 120. The electrode group plural unit cells that are electrically connected in parallel,
113 holds the electrolytic solution (not shown ). and the like .
As shown in FIG . 11, a belt -shaped positive electrode tab 45 The battery module may be housed in a housing . As the
114 is electrically connected to each of plural positions on housing, a metal can formed of aluminum alloy , iron ,
the edge of the positive electrode 110 located on the end stainless steel, or the like, or a plastic container, or the like
surface of the electrode group 113. Although not shown , a may be used . The container desirably has a wall thickness of
belt-shaped negative electrode tab 115 is electrically con 0.5 mm or more .
nected to each of plural positions on the edge of the negative 50 Examples of the aspect in which the plural lithium sec
electrode 111 located on the end surface . The plural positive ondary batteries are electrically connected in series or in
electrode tabs 114 are bundled into one, and electrically parallel include an aspect in which the plural secondary
connected to a positive electrode conductive lead 116. The batteries each has a container and are electrically connected
positive electrode tabs 114 ( the positive electrode internal in series or in parallel, and an aspect in which plural
terminals ) and the positive electrode conductive lead 116 55 electrode groups are housed in the same housing and are
(the positive electrode external terminal) compose the posi electrically connected in series or in parallel. Specific
tive electrode terminal . The negative electrode tabs 115 are examples of the former are those in which positive electrode
bundled into one , and connected to a negative electrode terminals and negative electrode terminals of plural lithium
conductive lead 117. The negative electrode tabs 115 (the secondary batteries are connected via metal bus bars (for
negative electrode internal terminals) and the negative elec- 60 example, aluminum , nickel, or copper). Specific examples of
trode conductive lead 117 (the negative electrode external the latter include an aspect in which plural electrode groups
terminal) compose the negative electrode terminal. are housed in one housing in a state of being electrochemi
A metal sealing plate 121 is fixed over an opening of the cally insulated from each other by partitions, and these
metal container 120 by welding or the like. The positive electrode groups are electrically connected to each other in
electrode conductive lead 116 and the negative electrode 65 series . When 5 to 7 batteries are electrically connected in
conductive lead 117 are respectively drawn out from outlets, series, for example , a battery module having good voltage
which are provided on the sealing plate 121 , to the outside . compatibility with a lead storage battery can be obtained . In
 US 10,727,540 B2
31 32
order to further increase the voltage compatibility with the 8. FIG . 7 is an exploded perspective view showing the
lead storage battery , a structure in which 5 or 6 unit cells are battery pack according to the sixth embodiment. FIG . 8 is a
connected in series is preferable . block diagram showing an electric circuit of the battery pack
One example of the battery module is explained with in FIG . 7 .
reference to FIG . 12 . 5 The battery pack shown in FIGS . 7 and 8 include plural
A battery module 131, shown in FIG . 12 , includes plural unit cells 51. Each of the plural unit cells 51 may be the
square-type secondary batteries 132 ,1 to 132 , according to flat -type lithium secondary battery explained with reference
the fourth embodiment ( for example, FIG . 10 and FIG . 11 ) to FIGS . 10 and 11 .
as unit cells. A positive electrode lead 116 of battery 1321 Plural unit cells 51 , i.e. flat -type secondary batteries, are
and a negative electrode lead 117 of battery 1322 positioned 10 stacked such that externally extending negative electrode
adjacent thereto , are electrically connected through a bus terminals 52 and positive electrode terminals 53 are
bar 133. Further, a positive electrode lead 116 of the battery arranged in the same direction , and the resulting stack is
1322 and a negative electrode lead 117 of battery 1323 fastened with an adhesive tape 54 to form a battery module
positioned adjacent thereto , are electrically connected 55. The unit cells 51 are electrically connected to each other
through a bus -bar 133. In this manner, the batteries 132 ,1 to 15 in Aseries , as shown in FIG . 8 .
printed wiring board 56 is disposed facing the side
132 , are connected in series.
According to the battery module of the fifth embodiment, surfaces of the unit cells 51 from which the negative
by including the lithium secondary battery according to the electrode terminals 52 and the positive electrode terminals
fourth embodiment, there can be provided a battery module 53 extend out. A thermistor 57, a protective circuit 58 , and
having high safety that is excellent in charge -and -discharge 20 an external power distribution terminal 59 are installed on
efficiency and charge-and -discharge cycle life because self the printed wiring board 56 , as shown in FIG . 8. An electric
discharge is suppressed . Furthermore , when 5 of the lithium insulating plate (not shown ) is attached to the surface of the
secondary batteries according to the fourth embodiment are printed wiring board 56 facing the battery module 55 to
connected in series , excellent compatibility with a lead avoid unnecessary connection with wirings of the battery
storage battery can be obtained . Therefore, the battery 25 module 55 .
module, in which 5 lithium secondary batteries are con A positive electrode lead 60 is connected to a positive
nected in series, is capable of being used as a backup power electrode terminal 53 located at the lowermost layer of the
source for a lead storage battery. battery module 55 , and the distal end of the lead 60 is
inserted into a positive electrode connector 61 on the printed
Sixth Embodiment 30 wiring board 56 and thus electrically connected to the
connector. A negative electrode lead 62 is connected to a
According to a sixth embodiment, a battery pack is negative electrode terminal 52 located at the uppermost
provided . The battery pack includes the lithium secondary layer of the battery module 55 , and the distal end of the lead
battery according to the fourth embodiment. 62 is inserted into a negative electrode connector 63 on the
The battery pack according to the sixth embodiment may 35 printed wiring board 56 and thus electrically connected to
include one or more lithium secondary batteries (unit cells ) the connector. The connectors 61 and 63 are connected to the
according to the fourth embodiment described above. The protective circuit 58 through wirings 64 and 65 formed on
plural lithium secondary batteries, which may be included in the printed wiring board 56 .
the battery pack according to the sixth embodiment, may be The thermistor 57 detects the temperature of the unit cell
electrically connected to each other in series , in parallel or 40 51 , and the detection signals are sent to the protective circuit
in a combination of in series and in parallel. The plural 58. The protective circuit 58 can shut down a plus wiring
lithium secondary batteriesmay be electrically connected to 66a and a minus wiring 66b between the protective circuit
compose a battery module . In the case of composing a 58 and the external power distribution terminal 59 under
battery module from plural secondary batteries, the battery predetermined conditions. A predetermined condition is , for
module according to the fifth embodiment may be used . 45 example , the case where the temperature detected by the
The battery pack according to the sixth embodiment may thermistor 57 becomes a predetermined temperature or
further include a protective circuit. The protective circuit has higher . Another example of the predetermined condition is
a function of controlling the charge and discharge of the the case when the over- charge, over-discharge or over
lithium secondary battery. Alternatively , a circuit included in current of the unit cells 51 is detected . The detection of the
equipment that uses the battery pack as a power source (for 50 over-charge, or the like, is performed for each individual
example , an electronic device, a vehicle such as an auto unit cell 51 or for the battery module 55. When each
mobile , or the like ) may be used as the protective circuit of individual unit cell 51 is detected , the battery voltage may be
the battery pack . detected , or the positive electrode potential or negative
Moreover, the battery pack according to the sixth embodi electrode potential may be detected . In the latter case , a
ment may further include an external power distribution 55 lithium electrode, which is used as a reference electrode, is
terminal . The external power distribution terminal is con inserted into each individual unit cell 51. In the case of FIG .
figured to externally output current from the lithium sec 7 and FIG . 8 , a wiring 67 for voltage detection is connected
ondary battery and/ or to input current into a unit cell 51. In to each of the unit cells 51, and the detected signals are sent
other words , when the battery pack is used as a power to the protective circuit 58 through the wirings 67.
source , the current is externally provided through the exter- 60 Protective sheets 68,made of rubber or resin , are arranged
nal power distribution terminal. When the battery pack is on three side planes of the battery module 55 except for the
charged , the charge current ( including a regenerative energy side plane from which the positive electrode terminals 53
of power of an automobile , or the like ) is provided to the and the negative electrode terminals 52 protrude out.
battery pack through the external power distribution termi The battery module 55 is housed in a housing container 69
nal. 65 together with the protective sheets 68 and the printed wiring
An example of the battery pack according to the sixth board 56. That is, the protective sheets 68 are arranged on
embodiment is explained with reference to FIG . 7 and FIG . both internal surfaces in a long side direction and one
 US 10,727,540 B2
33 34
internal surface in a short side direction of the housing Whether the first electrolyte and the electrolytic solution
container 69 , and the printed wiring board 56 is disposed on include water can be examined by GC -MS (Gas Chroma
the internal surface on the opposite side in the short side tography -Mass Spectrometry ) measurement. Calculation of
direction . The battery module 55 is located in a space salt concentration and water content in the first electrolyte
surrounded by the protective sheets 68 and the printed 5 and the electrolytic solution , measurementcan be performed
wiring board 56. A lid 70 is attached to the upper surface of by ICP ( Inductively Coupled Plasma) emission analysis , for
the housing container 69 . example. Specified amounts of the first electrolyte and the
In order to fix the battery module 55 , a heat-shrinkable electrolytic solution are weighed out, and a concentration of
tape may be used instead of the adhesive tape 54. In such a included salt is calculated , whereby a molar concentration
case, the battery module is fastened by placing the protective 10 (mol/L ) can be calculated . When the specific gravities of the
sheets on both side surfaces of the battery module, revolving first electrolyte and the electrolytic solution are measured ,
the heat -shrinkable tape around the battery module, and the number of moles of a solute and a solvent can be
thermally shrinking the heat-shrinkable tape . calculated .
In FIGS. 7 and 8 , an aspect has been shown in which the As the separator in the secondary battery according to the
unit cells 51 are connected in series ; however, in order to 15 first embodiment and the separator in the secondary battery
increase the battery capacity, the cells may be connected in according to the fourth embodiment, solid electrolytes may
parallel. Alternatively, the connection in series and the be used . As the solid electrolytes , oxides such as LATP
connection in parallel may be combined . Assembled battery (Li1 +xA1_T12- (PO4)3, where 0.1sx50.4 ) having a NASI
packs may be connected to each other in series or in parallel. CON -type skeleton , amorphous LIPON (Li2.9PO3.3No.46 ),
The aspect of the battery pack may be appropriately 20 and garnet- type LLZ (Li,LazZr2012) are preferable. The
changed depending on the application thereof. The battery respective features within the first to sixth embodiments may
pack is preferably used in applications in which charge-and be replaced with or combined with features ofother embodi
discharge at large current is desired . Specifically the battery ments .
pack may be used , for example, as a power source of a For example, a gel electrolyte included in the first elec
digital camera , as a battery for installing in a vehicle such as 25 trolyte may be applied to an electrolytic solution .
a two - to four-wheeled hybrid electric automobile, a two - to As the covering member containing the additive element
four -wheeled electric automobile , a power-assisted bicycle, included in the first embodiment, a covering member having
or a railway car , or as a stationary battery . In particular, the a layered shape , a covering member having a granular shape
battery pack is suitably used for a battery installed in a instead of or in combination with the layered shape , a
vehicle. 30 covering member having a fibrous shape, or the like may be
In a vehicle into which the battery pack according to the used . These forms may be applied to the covering layer
sixth embodiment has been installed , the battery pack is included in the fourth embodiment.
configured , for example, to recover regenerative energy The lithium salt that may be contained in the first elec
from power of the vehicle. Examples of the vehicle include trolyte and the lithium salt that may be contained in the
two- to four -wheeled hybrid electric automobiles, two- to 35 electrolytic solution of the third embodiment may be
four-wheeled electric automobiles , electric assist bicycles , replaced or combined with each other.
and railway cars such as electric trains. In any configuration , an excellent battery performance
FIG . 13 shows an example of an automobile that includes can be obtained .
a battery pack according to the sixth embodiment. The applications of the first to six embodiments include
The automobile 141 shown in FIG . 13 includes a battery 40 batteries for stationary use and batteries for use in railway
pack 142, which is an example of the battery pack according cars .
to the sixth embodiment, installed in the engine compart An aspect of a vehicle according embodiments is
ment at the front of the vehicle body. The installing position explained below , with reference to FIG . 14 .
is not limited to engine compartments. For example , the FIG . 14 is a view schematically showing an aspect of a
battery pack may also be installed in rear parts of the vehicle 45 vehicle having the secondary battery according the
body of automobiles or under seats . embodiments installed . A vehicle 300 , shown in FIG . 14 , is
According to the sixth embodiment described above, by an electric automobile .
including the lithium secondary battery according to the The vehicle 300, shown in FIG . 14 , includes a vehicle
fourth embodiment, there can be provided a battery pack power source 301, a vehicle ECU ( electric control unit ) 380,
having excellent safety that is excellent in charge -and- 50 which is a master controllerof the vehicle power source 301,
discharge efficiency and charge -and -discharge cycle life an external terminal (an external power connection terminal)
because self- discharge is suppressed . According to the 370 , an inverter 340, and a drive motor 345 .
embodiment, accordingly , it is possible to provide a battery The vehicle 300 includes the vehicle power source 301 ,
pack that is favorable as an alternative power source in place for example , in an engine compartment, in the rear sections
of a lead battery, which is used as a power source of a starter 55 of the automobile body ,or under a seat. In FIG . 14 , however,
for a vehicle , or as a secondary battery for installing in a the position of the secondary battery installed in the vehicle
hybrid car. 300 is schematically shown.
The electrolytes ( first electrolytes) according to the first to The vehicle power source 301 includes plural ( for
third embodiments and the electrolytic solutions (electro example , three ) battery packs 312a , 312b and 312c, BMU (a
lytic solutions each including the second electrolyte ) accord- 60 battery management unit ) 311, and a communication bus
ing to the fourth to sixth embodiments may include both 310 .
lithium ions and sodium ions. The three battery packs 312a , 312b and 312c are electri
In the first electrolyte and the electrolytic solution , water cally connected to each other in series . The battery pack
as a solvent is preferably contained in an amount of 1 mol 312a includes a battery module 314a and a battery module
or more relative to 1 mol of salt as a solute . In a more 65 monitoring unit (VTM : voltage temperature monitoring )
preferable embodiment, the amount of water as solvent is 313a . The battery pack 312b includes a battery module
3.5 mol or more relative to 1 mol of salt as a solute . 314b , and a battery module monitoring unit 313b . The
 US 10,727,540 B2
35 36
battery pack 312c includes a battery module 314c, and a One terminal of a connecting line L1 is connected to the
battery module monitoring unit 313c. The battery packs negative electrode terminal 317 of the vehicle power source
312a , 312b and 312c can each be independently removed , 301. The connecting line L1 is connected through a current
and may be exchanged by a different battery pack . detector (not shown ) in the battery management unit 311 to
Each of the battery modules 314a to 314c includes plural 5 a negative electrode input terminal of the inverter 340 .
secondary batteries connected to each other in series. The One terminal of a connecting line L2 is connected through
plural secondary batteries are, for example , the secondary the switch unit 333 to the positive electrode terminal 316 of
battery according to the first embodiment or the secondary the vehicle power source 301. The other terminal of the
battery according to the fourth embodiment. The battery connecting line L2 is connected to a positive electrode input
modules 314a to 314c each perform charging and discharg 10 terminal of the inverter 340 .
The external terminal 370 is connected to the battery
ing through a positive electrode terminal 316 and a negative management
electrode terminal 317 . unit 311. The external terminal 370 is able to
In order to collect information concerning security of the connect , for example, to an external power source .
vehicle power source 301, the battery management unit 311 15 The vehicleunit ECU 380 cooperatively controls the battery
performs communication among the battery module moni management 311 together with other units in response
toring units 313a to 313c and collects information such as the management of athe
to inputs operated by driver or the like , thereby performing
entire vehicle. Data transfer is
voltages or temperatures of the secondary batteries of the performed between the battery management unit 311 and the
battery modules 314a to 314c included in the vehicle power vehicle ECU 380 through communication lines, concerning
source 301 . 20 the security of the vehicle power source 301 , such as a
The communication bus 310 is connected between the remaining capacity of the vehicle power source 301 .
battery management unit 311 and the battery module moni In the vehicle including the secondary battery according
toring units 313a to 313c . The communication bus 310 is to the first embodiment, each of the battery packs 312a ,
configured so that multiple nodes ( i.e., the battery manage 312b , and 312c are able to exhibit excellent large current
ment unit and one ormore battery module monitoring units ) 25 discharge performance, cycle life performance, and storage
share a set of communication lines . The communication bus performance . Thus, vehicle performance , safety and reliabil
310 is, for example , a communication bus configured based ity can be secured .
on CAN (Control Area Network ) standard . In a vehicle including the secondary battery according to
The battery module monitoring units 313a to 313c mea the fourth embodiment, each of the battery packs 312a,
sure a voltage and a temperature of each secondary battery 30 312b , and 312c are able to exhibit excellent charge - and
that configure the battery modules 314a to 314c based on discharge cycles, and has high safety. Thus , stability , reli
communications from the batterymanagement unit 311. It is ability, and safety of the vehicle can be secured .
possible, er, to measure the temperatures only at
severalpoints per battery module and the temperatures of all EXAMPLES
of the secondary batteries need not be measured . 35
The power source for vehicle 301 may also have an Hereinafter , although examples of the disclosure will be
electromagnetic contactor (for example, a switch unit 333 described in detail with reference to the drawings, the
shown in FIG . 14 ) for switching connection between the disclosure is not limited to the following examples.
positive electrode terminal and the negative electrode ter
minal. The switch unit 333 includes a precharge switch (not 40 Example 1
shown ), which is turned on when the battery modules 314a
to 314c are charged , and a main switch (not shown ), which As a positive electrode active material, lithium manga
is turned on when battery output is supplied to a load . The nese oxide (LiMn204) particles having a spinel structure
precharge switch and the main switch include a relay circuit were used . In the LiMn204 particles, primary particles and
(not shown ), which is turned on or off based on a signal 45 secondary particles were mixed , and an average particle size
supplied to a coil located near a switch element. of the LiMn204 particles was 5 um . 3 % by weight of carbon
The inverter 340 converts an inputted direct current fibers of vapor-phase growth serving as an electro -conduc
voltage to a three phase alternate current (AC ) high voltage tive agent and having a fiber diameter of 0.1 um , based on
for driving a motor. The inverter 340 controls an output a weight of the positive electrode activematerial-containing
voltage based on control signals from the battery manage- 50 layer, 5 % by weight of a graphite powder as the electro
ment unit 311 or the vehicle ECU 380 , which controls the conductive agent, based on the weight of the positive
entire operation of the vehicle. A three phase output terminal electrode active material- containing layer, and 5 % by weight
of the inverter 340 is connected to each three phase input of polytetrafluoroethylene (PTFE ) as a binder, based on the
terminal of the drive motor 345 . weight of the positive electrode active material-containing
The drive motor 345 is rotated by electric power supplied 55 layer are mixed with a positive electrode activematerial, and
from the inverter 340, and transfers the rotation to an axle the resultant mixture was dispersed in water to prepare a
and driving wheels W , for example, through a differential slurry . The resultant slurry was applied onto both surfaces of
gear unit. a nickel foil having a thickness of 10 um , dried , and pressed
Although not shown, the vehicle 300 also includes a to produce a positive electrode. A thickness of each positive
regenerative brake mechanism , which rotates the drive 60 electrode active material-containing layer was 43 um . An
motor 345 when the vehicle 300 is braked , and converts electrode density was 2.2 g /cm3.
kinetic energy to regenerative energy , which is electric An anatase TiO2 powder having an average secondary
energy particle size (i.e., average secondary particle diameter ) of 10
The regenerative energy , recovered in the regenerative um , a zinc powder having an average particle size of 10 um ,
brake mechanism , is inputted into the inverter 340 and 65 and tetrafluoroethylene (PTFE ) as a binder were mixed so
converted to direct current. The direct current is inputted that the weight ratio was 80 : 17 :3 and then dispersed in
into the vehicle power source 301. water. The resultant dispersion was stirred using a ball mill
 US 10,727,540 B2
37 38
under conditions in which rotational speed was 1000 rpm As the negative electrode active materials of Examples 2
and a stirring time was two hours to prepare a slurry. The and 3, a Li Tis012 powder having a spinel structure and
resultant slurry was applied onto a nickel foil having a having an average secondary particle size (average second
thickness of 10 um , dried , and heat-pressed to produce a ary particle diameter ) of 0.8 um was used .
negative electrode in which a thickness of each negative 5
electrode active material -containing layer was 59 um , and Example 5
the electrode density was 2.2 g /cmº.
A nonwoven fabric made of cellulose fibers, having an A secondary battery was produced similarly to Example 1
average fiber diameter of 1 um , and having a thickness of 20 except that a surface of negative electrode active material
um and a porosity of 65 % was provided as a separator. A 10 particles was not covered with a covering member by
surface of the positive electrode was covered with the changing the electrolytic solution composition to the com
separator, and the negative electrodes are spirally wound position shown in Table 1.
while being laminated such that the negative electrode active
material-containing layer faces the positive electrode active Example 6
material-containing layer through the separator , thus pro- 15
ducing an electrode group . At that time, an electrode width ALi Ti 012 powder having an average secondary particle
of the positive electrode active material-containing layer size similar to Examples 2 and 3 was covered with a
was 50 mm , and an electrode width of the negative electrode covering member made of Li3T11.7A1, .3 (PO4)3. A thin
active material-containing layer was 51 mm . Thus, in the secondary battery was produced similarly to Example 1
electrode group , a long side of the negative electrode active 20 except that negative electrode active material particles with
material -containing layer was projected from a long side of a covering member were used , and a positive electrode
the positive electrode active material-containing layer. active material, a thickness of a negative electrode covering
This electrode group was pressed to be formed into a flat member, a kind of a material mixed in the negative elec
shape. The electrode group was stored in a thin metal can trode, a mixing ratio , an aqueous electrolytic solution com
container made of stainless steel and having a thickness of 25 position , and pH were set to the values shown in Table 1.
0.25 mm . In that metal can , a valve which leaks gas when
the internal pressure exceeded 2 atmosphere pressure was Example 7
installed .
On the other hand , as an electrolytic solution, i.e., a first A Li TiO 2 powder having an average secondary particle
electrolyte, 6 M of LiCl, 0.5 M of ZnSO4 and 0.25 M of 30 size similar to Examples 2 and 3 was covered with a
Li2SO4 were dissolved in 1 L of water , and LiOH was added covering member made of Liz..Ge ... V0.404. A thin second
such that a pH value was 11, thus preparing an alkali ary battery was produced similarly to Example 1 except that
aqueous solution . The electrolytic solution was injected into negative electrode active material particles with a covering
the electrode group in the container, and a thin secondary member were used , and a positive electrode active material,
battery having the above -mentioned structure shown in FIG . 35 a thickness of a negative electrode covering member , a kind
1 and having a thickness of 16 mm , a width of 40 mm , and of a materialmixed in the negative electrode , a mixing ratio ,
a height of 60 mm was produced . an aqueous electrolytic solution composition , and pH were
When initial charge/ discharge was applied to the obtained set to the values shown in Table 1 .
secondary battery such that after the secondary battery was
charged up to 2.7 V by a constant current of 6 A at 25 ° C., 40 Example 8
the secondary battery was discharged up to 1.5 V at 3 A , zinc
was deposited on a surface of the anatase TiO2 particles as A thin secondary battery was produced similarly to
the negative electrode active material to cover at least a Example 1 except that a TiO2 ( B ) powder having a mono
portion of the surfaces of the TiO2 particles with a zinc metal clinic structure and having an average secondary particle
layer having a thickness of 0.05 um . Table 1 shows, as 45 size (average secondary particle diameter) of 10 um was
mixing ratio (% by weight), results calculated from the provided as a negative electrode active material, and a zinc
formula ( 1) in which W ,1 is a weight of the zinc powder, and powder is not added to a negative electrode.
W , is a total weightof the anatase TiO2 particles and the zinc In order to change a thickness of a zinc metal layer,
metal layer. covering surfaces of negative electrode active material par
50
ticles , to 0.1 um , an initial charge /discharge condition of the
Examples 2 to 4 secondary battery was changed to a condition in which the
secondary battery was charged up to 2.7 v by a constant
Thin secondary batteries were produced similarly to current of 2 A at 25 ° C. and then discharged up to 1.5 V at
Example 1 except that positive electrode active materials , 3 A.
negative electrode active materials, negative electrode cov- 55
ering members , thicknesses of the negative electrode cov Example 9
ering members, kinds of materials mixed in the negative
electrode, mixing ratio , aqueous electrolytic solution com As a negative electrode active material , an Nb TiO ,
positions, and pH were set to the values shown in Table 1. powder having an average secondary particle size (average
The covering member of Example 3 made of ZrO2 was 60 secondary particle diameter) of 2 um was provided . A thin
produced by the following method . Zr(NO3)2.3H20 was secondary battery was produced similarly to Example 1
added to an aqueous solution of 2 % by weight polyvinyl except that a positive electrode active material, a negative
pyrrolidone , a Li Tis012 powder and water were added to electrode covering member, a thickness of the negative
this solution , and the resultant solution was stirred for six electrode covering member, a kind of a material mixed in the
hours. After that, the resultant product was heat- treated at 65 negative electrode, a mixing ratio , an aqueous electrolytic
600° C. in air for three hours, thus obtaining Li Ti 012 solution composition , and pH were set to the values shown
covered with ZrO2. in Table 1 .
 US 10,727,540 B2
39 40
Examples 10 and 11 After that, the resultant product was heat-treated at600 ° C.
in air for three hours, thus obtaining Li Ti,012 covered with
ALi Ti 012 powder having an average secondary particle Zno .
size similar to Examples 2 and 3 was covered with a Zn particles having an average particle size of 10 um were
covering member made of Li,LazZr2012. A thin secondary 5 covered with ZnO under the following conditions, thus
battery was produced similarly to Example 1 except that obtaining Zn particles whose surfaces were covered with a
negative electrode active material particles with a covering ZnO film .
member were used , and a positive electrode active material, After the Zn particles were immersed in an alkaline
a thickness of a negative electrode covering member, a kind 10
aqueous solution of pH 9 for three hours , washing with
of a material mixed in the negative electrode, a mixing ratio , water was performed , and heat treatment was performed at
an aqueous electrolytic solution composition , and pH were 200 ° C. in air for six hours, thus obtaining the Zn particles
set to the values shown in Table 1 . covered with ZnO .
Examples 12 to 20 A thin secondary battery was produced similarly to
15 Example 1 except that the negative electrode active material
Thin secondary batteries were produced similarly to and the particles of the additive element were used , and a
Example 1 except that positive electrode active materials , positive electrode active material, a thickness of a negative
negative electrode active materials , negative electrode cov electrode covering member, a mixing ratio , an aqueous
electrolytic solution composition , and pH were set to the
ering members , thicknesses of the negative electrode cov values shown in Table 2 .
ering members, kinds of materials mixed in the negative 20
electrode, a mixing ratio, aqueous electrolytic solution com Example 23
positions, and pH were set to the values shown in Table 1 .
Example 21 A thin secondary battery was produced similarly to
25 Example 21 except that a negative electrode covering mem
In a Li Ti 0,2 powder having an average secondary ber is not used, and a mixing ratio was set to the value shown
particle size similar to Examples 2 and 3 , a covering member in Table 2 .
made of Al2O3 was produced by the following method .
Al(NO3)2.9H20 was added to an aqueous solution prepared Example 24
by mixing 5 ml of polyvinyl alcohol and 10 ml of water , a 30
Li Tis012 powder and 10 ml of water were added to this A thin secondary battery was produced similarly to
solution , and the resultant solution was stirred for six hours .
After that, the resultant product was heat- treated at 600 ° C. Example 22 except that a negative electrode covering mem
in air for three hours, thus obtaining Li Ti;012 covered with 35 ber is not used , and a mixing ratio was set to the value shown
in Table 2 .
Al2O3.
Alparticles having an average particle size of 50 um were
subjected to alumite treatment under the following condi Comparative Examples 1 to 7
tions, thus obtaining Al particles whose surfaces were cov
ered with an A1203 film . Thin secondary batteries were produced similarly to
An electrode is produced by holding a powder including 40 Example 1 except that positive electrode active materials ,
Al particles between two Al plates having a plural of holes, negative electrode active materials, negative electrode cov
and electrolysis was performed at a voltage of 30 V ( Al ering members , thicknesses of the negative electrode cov
plates serving as counter electrodes) with the use of a 5 % ering members, kinds of materials mixed in the negative
oxalic acid aqueous solution as an electrolytic solution bath . electrode
After the electrode was taken out from the electrolytic 45 positions,, aand mixing ratio , aqueous electrolytic solution com
pH were set to the values shown in Table 1.
solution bath , the electrode was washed with water and then
In Examples
immersed in boiling water for 10 minutes. After that, the electrolytic solution and Comparative Examples, the pH of each
electrode was dried to remove the Al particles from the Al adding sulfuric acid or was adjusted to an intended value by
plates, thus obtaining the Al particles whose surfaces were LiOH .
covered with an Al2O3 film . 50 After each of the obtained secondary batteries of
A thin secondary battery was produced similarly to Examples and Comparative Examples was charged up to 2.7
Example 1 except that the negative electrode active material V by a constant current of 6 A at 25° C., a discharge capacity
and the particles of the additive element were used , and a obtained when the secondary battery was discharged up to
positive electrode active material , a thickness of a negative 1.5 V at 3 A was measured . As a cycle test, a charge -and
electrode covering member, a mixing ratio , an aqueous 55 discharge cycle in which the secondary battery was charged
electrolytic solution composition , and pH were set to the up to 2.7 V by a constant current of 6 A at 25 ° C. and then
values shown in Table 2 . discharged up to 1.5 V at 3 A was repeated , and a cycle
number obtained when the discharge capacity reaches a
Example 22 value corresponding to 80 % of an initial capacity was taken
60 to be a cycle life . As a large current discharge performance
In a Li Ti 012 powder having an average secondary test, the secondary battery was charged up to 2.7 V at 6 A and
particle size similar to Examples 2 and 3 , a coveringmember then discharged up to 1.5 V at 100 A , and a capacity
made of ZnO was produced by the following method . retention at that time was obtained . As a storage test, the
Zn (NO3)2.6H20 was added to an aqueous solution prepared secondary battery was charged up to 2.7 V at 6 A and then
by mixing 5 ml of polyvinyl alcohol and 10 mlof water, a 65 stored at 30 ° C. for one week , and the self-discharge rate
Li Ti 012 powder and 10 ml of water were added to this thereafter was obtained . Those measurement results are
solution, and the resultant solution was stirred for six hours. shown in the following Tables 3 to 4 .
 US 10,727,540 B2
41 42
TABLE 1
Negative Material Mixing
Positive electrode mixed in ratio Aqueous electrolytic
electrode active Negative electrode Thickness negative ( % by solution
active material material covering member (um ) electrode weight) composition pH
Example 1 LiMn204 TiO2 Zn 0.05 Zn 21.25 6 M / L LiCl + 11
(anatase ) 0.5 M /L ZnSO4 +
0.25 M /L Li2SO4
Example 2 LiMn204 LiqTis012 Zn 0.05 Zn 5 6 M / L LiCl + 11
0.5 M /L ZnSO4 +
0.25 M /L Li2SO4
Example 3 LiMn204 Li Tig012 ZrO2 0.01 Zn 21.25 6 M / L LiCl + 11
0.5 M /L ZnSO4 +
0.25 M /L Li2SO4
Example 4 LiMn204 TiO2 Zn 0.05 Zn 2 6 M / L LiCl + 5
(anatase ) 0.5 M /L ZnSO4 +
0.25 M /L Li2SO4
Example 5 LiMn204 TiO2 Zn 21.25 4 M / L LiCl + 8
(anatase ) 0.25 M /L Li2SO4
Example 6 LiMn204 Li Tiz012 Li1.3Ti1.7A10.3 (PO4)3 0.02 Zn 21.25 4 M / L LiCl + 11
0.25 M /L Li2SO4
Example 7 LiMn204 Li Tig012 Li3.6G80.6V0.404 0.02 Zn 21.25 4 M / L LiCl + 11
0.25 M /L Li2SO4
Example 8 LiMn204 TiO2(B ) Zn 0.1 — 6 M / L LiCl + 11
0.5 M /L ZnSO4 +
0.25 M /L Li2SO4
Example 9 LiMn204 Nb Ti07 — Zn 21.25 4 M / L LiCl + 11
0.25 M / L Li2SO4
Example LiMn204 LidTig012 LizLazZr2012 0.01 Zn 21.25 4 M / L LiCl + 12
10 0.5 M /LINO3
Example LiMn204 Li Tig012 Li LazZr2012 0.01 Zn 21.25 4 M / L LiCl + 12
11 0.1 M /L LIB [ (OCO ) 212
Example LiMno. Fe0.1PO4 TiO2 Zn 21.25 8 M / L LiCl + 11
12 (anatase ) 0.25 M / L Li2SO4
Example LiMn204 TiO2 Zn 0.05 — 6 M / L LiCl + 5
13 (anatase ) 0.5 M /L ZnSO4 +
0.25 M /L Li2SO4
Example LiMn204 Li Tig012 Zn 21.25 6 M /L LINO3 + 5
14 0.25 M /L Li2SO4
Example LiMn204 Li Tis012 Zn 0.05 Zn 25 6 M /L LiCl + 5
15 0.5 M /L ZnSO4 +
0.25 M /L Li2SO4
Example LiMn204 Li Tig012 Zn 0.05 Zn 30 6 M / L LiCl + 6
16 0.5 M /L ZnSO4 +
Example LiMn204
0.25 M /L Li2SO4
Li Tig012 Zn 30 6 M /L LINO3 + 3
17 0.25 M /L Li2SO4
Example LiMn204 TiO2 Zn 30 6 M /L LINO3 + 5
18 (anatase ) 0.25 M /L Li2SO4
Example LiFePO4 Li Tig012 Zn 0.05 Zn 25 6 M / L LiCl + 5
19 0.5 M /L ZnSO4 +
0.25 M /L Li2SO4
Example LiNi0.5CO0.2M10.302 Li Tis012 Zn 0.05 Zn 25 6 M / L LiCl + 5
20 0.5 M /L ZnSO4 +
0.25 M /L Li2SO4

TABLE 2
Positive Negative Negative Material Mixing
electrode electrode electrode mixed in ratio Aqueous electrolytic
active active covering Thickness negative ( % by solution
material material member (um ) electrode weight) composition pH
Example LiMn204 Li Tig012 Al2O3 0.01 Al covered 5 4 M / L LiCl + 5
21 with Al2O3 0.25 M /L Li2SO4
Example LiMn204 LidTig012 ZnO 0.1 Zn covered 5 4 M / L LiCl + 5
22 with Zno 0.25 M /L Li2SO4
Example LiMn204 Li Tig012 Al covered 10 4 M / L LiCl + 5
23 with Al2O3 0.25 M /L Li2SO4
Example LiMn204 Li Tig012 Zn covered 20 4 M / L LiCl + 5
24 with Zno 0.25 M /L Li2SO4
Comparative LiMn204 VO2 3 M / L LiCl +
Example 1 0.25 M /L Li2SO4
Comparative LiMn204 LiV308 3 M / L LiCl + 8
Example 2 0.25 M / L Li2SO4
 US 10,727,540 B2
43 44
TABLE 2 - continued
Positive Negative Negative Material Mixing
electrode electrode electrode mixed in ratio Aqueous electrolytic
active active covering Thickness negative ( % by solution
material material member (um ) electrode weight) composition pH
Comparative LiMn204 TiO2 3 M / L LiCl + 11
Example 3 ( anatase ) 0.25 M /L Li2SO4
Comparative LiMn204 TiO2 3 M / L LiCl + 8
Example 4 (anatase) 0.25 M / L Li2SO4
Comparative LiMn204 TiO2 3 M / L LiCl + 7.5
Example 5 ( anatase ) 0.25 M / L Li2SO4
Comparative LiMn204 Li Tig012 3 M / L LiCl + 8
Example 6 0.25 M / L Li2SO4
Comparative LiMn204 Li Tig012 TiO2 3 M / L LiCl + 8
Example 7 (anatase ) 0.25 M /L Li2SO4

TABLE 3 As seen in Tables 1 to 4 , the secondary batteries of

Large
Examples 1 to 24 are excellent in discharge capacity, large
current 30 ° C. current discharge performance , cycle life performance, and
25 ° C. discharge Cycle storage
20
storage performance as compared with Comparative
discharge capacity life self Examples 1 to 7 .
capacity retention (cycle discharge By comparing Example 1 and Example 5 , it is found that
(mAh ) rate (% ) number) rate ( % ) the cycle life performance of Example 1 in which a zinc
Example 1 3000 90 2400 10 25 containing layer is formed on surfaces of negative electrode
Example 2 3100 85 2000 6 active material particles is more excellent than that of
Example 3 2800 80 2000 10 Example 5 .
Example 4 3000 70 2100 8
By comparing Examples 2 , 3, 6 , 7 , 10 , 11, 21, and 22 in
Example 5 3100 95 2200 10
Example 6 3000 75 2200 10 which the negative electrode active material is a lithium
Example 7 3000 70 2000 10 30 titanium oxide having a spinel structure, it is found that
Example 8
Example 9
3100
3300
75
80
1500 6
10
Example 2 using the coveringmember containing zincmetal
Example 10 3000 80
1800
2000 10 is more excellent in discharge capacity and large current
Example 11 3000 80 2200 9 discharge performance than other examples .
Example 12 3100 80 3000 10 As can be seen from the results of Examples 5 , 8 , 9 , and
Example 13 3000 70 1800 8 35 14 , excellent performances can be obtained even if the kind
Example 14 3000 85 2200 12
of the negative electrode active material is changed . As can
Example 15 3200 90 2400 6
be seen from the results of Examples 1, 12 , 19 , and 20 ,
Example 16 3200 92 2800 6
Example 17 2800 90 2600 12 excellent performances can be obtained even if the kind of
Example 18 2500 90 2500 12 the positive electrode active material is changed .
Example 19 3300 70 3000 5 40 As can be seen from the results of Examples 21 to 24 , by
Example 20 3500 80 2000 6
virtue of the use of Al particles whose surfaces are covered
with an Al2O3 film or Zn particles whose surfaces are
covered with a ZnO film , excellent cycle life performance
TABLE 4 can be obtained .
45 As can be seen from the results of Comparative Examples
Large 4 , 6 , and 7, in Comparative Example 7 using a mixture of
25 ° C.
current
discharge Cycle
30 ° C.
storage
titanium dioxide and a lithium titanium oxide in the negative
discharge capacity life self electrode active material, the discharge capacity, the large
capacity retention (cycle discharge current discharge performance, the cycle life performance,
(mAh ) rate ( % ) number ) rate ( % ) 50 and the storage performance are as inferior as those of
Example 21 2800 70 3000 5 Comparative Examples 4 and 6 using one kind of the
Example 22 3000 80 2800 7 negative electrode active material.
Example 23 2800 70 2800 8 Although other examples will be explained below , the
Example 24 3000 80 2500 10 disclosure is not limited to the examples described below ,
Comparative 1500 50 500 40
Example 1 55 while not departing from the scope of the disclosure .
Comparative 1600 40 300 50
Example 2 Example 101
Comparative 1000 30 300 30
Example 3 (Production of Battery for Evaluation )
Comparative 500 30 100 50
60 First, N -methylpyrrolidone (NMP ) was added to and
Example 4
Comparative 100 10 20 90 mixed with 100 parts by weight of an olivine type LiMn204
Example 5
Comparative
powder as a positive electrode active material, 10 parts by
Example 6
1000 40 20 90
weight of acetylene black as an electro - conductive agent,
Comparative 1100 30 20 80 and 10 parts by weight of polyvinylidene fluoride (PVDF ) as
Example 7 65 a binder, thus preparing a positive electrode slurry . The
prepared slurry was coated onto one surface of a Ti foil as
a positive electrode current collector, a coating of the slurry
 US 10,727,540 B2
45 46
was dried and then pressed , whereby a positive electrode electrode current collector, and 20 mM of ZnCl2 and 10 mm
sheet having an electrode density of 2.6 g/cm was pro of saccharin sodium salt as additives were added to an
duced . The produced positive electrode sheet was punched electrolytic solution .
into a circle of q 10 mm , thus obtaining a disc - shaped Example 104
positive electrode. 5

Next, N -methylpyrrolidone (NMP) was added to and A battery for evaluation was produced similarly to
mixed with 100 parts by weight of a spinel type Li Ti 012 Example 101 except that a Ti foil was used as a negative
powder as a negative electrode active material, 10 parts by electrode current collector, and 10 mM of ZnCl2, 10 mM of
weight of acetylene black as an electro -conductive agent, 10 InCiz , and 10 mM of saccharin sodium salt as additives were
and 10 parts by weight of polyvinylidene fluoride (PVdF ) as added to an electrolytic solution.
a binder , thus preparing a negative electrode slurry. The
prepared slurry was coated onto one surface of a Zn foil as Example 105
a negative electrode current collector, a coating of the slurry
was dried and then pressed , whereby a negative electrode 15
A battery for evaluation was produced similarly to
sheet having an electrode density of 2.0 g/cm² was pro Example 101 except that a Ti foil was used as a negative
duced . The produced negative electrode sheet was punched electrode current collector, and 10 mM of ZnCl2, 10 mM of
into a circle of q 10 mm , thus obtaining a disc -shaped CuCl2, and 10 mM of saccharin sodium salt as additives
negative electrode . were added to an electrolytic solution .
A three electrode type cell having the configuration shown
in FIG . 9 was produced using the produced positive and 20 Example 106
negative electrodes. In the cell, as a positive electrode
external terminal (positive electrode can) and a positive A battery for evaluation was produced similarly to
electrode internal terminal, a Ti plate and a Ti wire were Example 101 except that a Ti foil was used as a negative
used , respectively, and they were resistance -welded to pro 25 electrode current collector, and 20 mM of SnCl2 and 10 mm
vide an integrated positive electrode terminal. As a negative of saccharin sodium salt as additives were added to an
electrode terminal (negative electrode can ), an aluminum electrolytic solution .
plate was used , and a portion of the internal surface that
becomes in contact with an electrolytic solution was insu Comparative Example 101
lated with Kapton tape (registered trademark ,manufactured 30
by Du Pont- Toray Co., Ltd.). A battery for evaluation was produced similarly to
12 ml of a 12 M LiCl aqueous solution as an electrolytic Example 101 except that a Ti foil was used as a negative
solution, that is, an aqueous solution of the second electro electrode current collector .
lyte was put into the produced three electrode type cell . The Comparative Example 102
concentration of the electrolytic solution was measured by 35
the ion chromatography method .
As described above , the battery for evaluation ofExample A battery for evaluation was produced similarly to
101 was produced . Example 101 except that a Ti foil was used as a negative
electrode current collector, LiTiZ (PO4)3 was used as a
Example 102 negative electrode active material, and 20 mM of ZnCl2 as
40 an additive was added to an electrolytic solution .
A battery for evaluation was produced similarly to The following table 5 summarizes, for each of Examples
Example 101 except that a Ti foil was used as a negative 101 to 106 and Comparative Examples 101 and 102 , the
electrode current collector, and 20 mM of ZnCl2 as an material of the current collector and the composition of the
additive was added to an electrolytic solution . active material in each of the positive and negative elec
45 trodes used in the manufacturing of the battery for evalua
Example 103 tion , the composition and concentration of the electrolyte
used in the electrolytic solution , the additive added to the
A battery for evaluation was produced similarly to electrolytic solution and concentration thereof, and pH of
Example 101 except that a Ti foil was used as a negative the electrolytic solution.
TABLE 5
Negative electrode
Li insertion / extraction
Positive electrode potential Electrolytic solution
Current Active Current Active of active material Electrolyte Additive
collector material collector material ( V vs. SCE ) (M ) (mm ) pH
Example Ti LiMn204 Zn Li Tiz012 -1.52 LiCl (12) 3.1
101
Example Ti LiMn204 Ti Li Tig012 -1.52 LiCl ( 12 ) ZnCl2 (20 ) 3.1
102
Example Ti LiMn204 Ti Li Tis012 -1.52 LiCl (12 ) ZnCl2 ( 20 ) 3.0
103 saccharin ( 10)
Example Ti LiMn204 Ti Li Tig012 -1.52 LiCl ( 12 ) ZnCl, (10 ) 3.0
104 InCl3 ( 10 )
saccharin (10 )
 US 10,727,540 B2
47 48
TABLE 5 - continued
Negative electrode
Li insertion/ extraction
Positive electrode potential Electrolytic solution
Current Active Current Active of active material Electrolyte Additive
collector material collector material (V vs. SCE ) (M ) (MM ) pH
Example Ti LiMn204 Ti Li Ti5012 -1.52 LiCl ( 12) ZnCl2 ( 10) 2.9
105 CuCl2 ( 10 )
saccharin ( 10)
Example Ti LiMn204 Ti Li Tig012 -1.52 LiCl (12 ) SnCl2 (20 ) 2.8
106 saccharin ( 10 )
Comparative Ti LiMn204 Ti LifTis012 -1.52 LiCl (12) 3.1
Example 101
Comparative Ti LiMn204 Ti LiTiZ(PO4)3 -0.75 LiCl (12 ) ZnCl2 ( 20 ) 3.1
Example 102

The following table 6 summarizes the conditions of the test. The discharge capacity after charge and discharge at the
initial charge and discharge of the battery for evaluation 20 twentieth cycle was taken to be the discharge capacity after
manufactured in each of Examples 101 to 106 and Com 20 cycles . A value obtained by dividing the discharge
parative Examples 101 and 102. capacity after 20 cycles by the discharge capacity before the
cycle test was calculated as a capacity retention ratio after 20
TABLE 6 cycles.
Charge- and -discharge conditions 25 An average value of charge-and -discharge efficiency for
each cycle when charge and discharge were performed for
Negative Negative 20 cycles was taken to be the charge- and -discharge effi
electrode electrode ciency after 20 cycles.
potential potential The following table 7 summarizes the capacity retention
at charge at discharge 30 ratio after 20 cycles and the charge -and- discharge efficiency
Current reached reached
Temperature density
(° C .) (mA /cm²) ( V vs. SCE ) (V vs. SCE ) after 20 cycles obtained in each of Examples 101 to 106 and
Comparative Examples 101 and 102.
Example 25 4.0 -1.6 -1.3
101
Example 25 4.1 -1.6 -1.3 TABLE 7
102 35
Example 25 3.9 -1.6 -1.3 Capacity retention rate Charge -and-discharge
103 after 20 cycles efficiency after 20 cycles
Example 25 4.0 -1.6 -1.3 (% ) (% )
104
Example 25 4.1 -1.6 -1.3
Example 94.2 86.0
101
105 40 Example 89.5
Example 25 3.9 -1.6 -1.3 82.6
106 102
Comparative 25 4.0 -1.6 -1.3
Example 90.2 89.4
103
Example 101 Example 91.2 87.1
Comparative 25 3.9 -0.9 -0.4
104
Example 102 45 Example 92.0 80.1
105
Example 88.7 81.5
( Constant-Current Charge -and -Discharge Test ) 106
For each of the batteries for evaluation manufactured in Comparative 71.5 80.0
Examples 101 to 106 and Comparative Examples 101 and Example 101
102, a constant-current charge -and -discharge test was con- 50 Comparative 81.2 82.0
ducted by controlling the voltage of the negative electrode Example 102
under a temperature condition of 25 ° C. and a condition of
a current value of 5 C rate . Regarding charging, the battery (Analysis of Composition and Thickness of Covering Layer )
was charged until the negative electrode potential reached For each of the batteries for evaluation manufactured in
-1.6 V ( vs. SCE ), and charging was performed in a constant 55 Examples 101 to 106 and Comparative Examples 101 and
current/constant voltage mode (CCCV ) in which charging 102 , the composition and layer thickness of the covering
was stopped once the current value reached 2.5 C or after a layer in each member in the negative electrode were ana
lapse of 20 minutes from the start of charging . Regarding lyzed . As a result , it was found that in Example 101, the
discharging , constant current discharge where the battery covering layer including a ZnO phase was present on all of
was discharged until the negative electrode potential reached 60 the negative electrode active material, the electro -conduc
-1.3 V was performed . One cycle was set as being charging tive agent, and the negative electrode current collector. In
once and discharging once . No interruption time was pro Example 101, it is considered that since a Zn foil was used
vided after either charge or discharge, and charge and as the negative electrode current collector, the covering layer
discharge were repeated for 20 cycles . including the ZnO phase was formed due to zinc eluted from
When charge and discharge at the first cycle were per- 65 the Zn foil.
formed , the discharge capacity of the battery was measured Also in Examples 102 and 103 , it had been confirmed that
and was taken to be the discharge capacity before the cycle the covering layer including the ZnO phase was formed on
 US 10,727,540 B2
49 50
the surface of each member. In Examples 102 and 103, confirmed in any of the negative electrode active material,
unlike Example 101 , although a Ti foil was used as the the electro - conductive agent, and the negative electrode
negative electrode current collector instead of a Zn foil , current collector. In Comparative Example it is con
ZnCl2 as an additive was contained in the electrolytic sidered that since an element, which may serve as the
solution. It is considered that the covering layer including 5
constituent element of the covering layer, was not included
the ZnO phase was formed due to ZnCl2 . in either of the negative electrode and the electrolytic
In Example 104 , the covering layer including a ZnO phase solution , no covering layer was formed . In Comparative
and an In2O3 phase was formed on surfaces of each of the
negative electrode active material, the electro -conductive Example 102 , although ZnCl2 as an additive was contained
agent, and the negative electrode current collector. In 10 in the electrolytic solution , no covering layer was formed . It
example 4 , ZnCl2 and InClz as additives were contained in is considered that, since the operating potential of LiTiz
the electrolytic solution . It is considered that the covering (PO4)3 used as the negative electrode active material was too
layer including Zn and In was formed due these additives . high , the negative electrode potential did not become low
In Example 105 , the covering layer including a ZnO phase
and a Cu phase was formed on each of the negative electrode 15 enough , so that a reaction in which a covering layer is
active material, the electro -conductive agent, and the nega formed of ZnCl2 did not occur.
tive electrode current collector . In Example 105 , ZnCl2 and The following Table 8 summarizes, for each of the nega
CuCl2 as additives were contained in the electrolytic solu tive electrode active material, the electro -conductive agent,
tion . It is considered that the covering layer including the and the negative electrode current collector included in the
ZnO phase and the Cu phase was formed due to these 20 negative electrode in the battery for evaluation in each of
additives . Examples 101 to 106 and Comparative Examples 101 and
In Example 106 , the covering layer including a SnO phase 102 , the component of the covering layer (composition of a
was formed on all of the members. In Example 106 , SnCl2 confirmed phase ), the abundance ratio between the constitu
as an additive was contained in the electrolytic solution . It ent elements in the covering layer, the thickness of the
is considered that the covering layer including the SnO 25 covering layer, and the cover ratio of the covering layer on
phase was formed of SnCl2 . the surface .
TABLE 8
Negative electrode active material Electro -conductive agent Negative electrode current collector
Abun Abun Abun
dance dance dance
ratio of ratio of ratio of
Component constituent Thick Cover Component constituent Thick Cover Component constituent Thick Cover
of covering elements ness ratio of covering elements ness ratio of covering elements ness ratio
layer (at % ) (nm ) ( % ) layer (at % ) (nm ) ( % ) layer (at % ) (nm ) (% )
Example Zno Zn (49 % ), 10 54 Zno Zn (47 % ), 20 14 Zno Zn (50 % ), 3000 99
101 O (51 % ) O (53 % ) O (50 % )
Example Zno Zn (48 % ), 2 25 Zno Zn (47 % ), 4 13 Zno Zn (49 % ), 50 96
102 0 (52 % ) O (53% ) O (51% )
Example Zno Zn (47 % ), 2 30 Zno Zn (45 % ), 5 12 Zno Zn (50 % ), 30 95
103 O (53 % ) O (55 % ) O (50 % )
Example Zno , Zn ( 13 % ), 3 35 Zno , Zn ( 15 % ), 4 12 ZnO , Zn ( 15 % ), 25 96
104 In203 In (30 % ) In203 In (27 % ) In2O3 In ( 30 % )
O (57 % ) O (58 % ) O (55 % )
Example ZnO , Zn (23 % ), 10 45 ZnO , Zn (24 % ), 20 14 ZnO , Zn ( 26 % ), 100 99
105 Cu Cu (54 % ) Cu Cu (49 % ) Cu Cu (47 % ),
O (23 % ) O (27 % ) O (27 % )
Example Sno Sn (54 % ), 10 37 Sno Sn (52 % ), 15 20 Sno Sn (55 % ), 30 97
106 O (46 % ) O (48 % ) O (45 % )
Comparative —
Example
101
Comparative
Example
102

In Examples 101 to 106 , since Li Ti2012 was used as the 55 As shown in Table 7 , as compared with the batteries for
negative electrode active material as shown in Table 5 , the evaluation manufactured in Examples 101 to 106 , in the
negative electrode potential reached -1.6 V (vs. SCE ) as batteries for evaluation manufactured in Comparative
shown in Table 6 in the initial discharge of the battery for Examples 101 and 102 , at least one of the capacity retention
evaluation . Thus, it is considered that due to electrodeposi ratio after 20 cycles and the charge- and-discharge efficiency
tion during initial charge, in Example 101, the covering layer 60 after 20 cycles was low . As described above, in Examples
was formed from a Zn element eluted from a Zn foil as the 101 to 106 , the negative electrode included the covering
negative electrode current collector, and in each of layer , while on the other hand , in Comparative Examples
Examples 102 to 105, the covering layer was formed from 101 and 102 , the negative electrode included no covering
the respective additive ( ZnCl2, InCl2, CuCl2, or SnCl2) layer. It is considered that in Comparative Examples 101 and
added to the electrolytic solution . 65 102 , since the negative electrode included no covering layer,
On the other hand, in both Comparative Examples 101 a reaction between each member (the negative electrode
and 102 , the formation of the covering layer could not be active material, the electro -conductive agent, and the nega
 US 10,727,540 B2
51 52
tive electrode current collector) in the negative electrode and electrolytic solution and concentration thereof, and pH of
the electrolytic solution and self-discharge could not be the electrolytic solution .
TABLE 9
Negative electrode
Li insertion / extraction
Positive electrode potential Electrolytic solution
Current Active Current Active of active material Electrolyte Additive
collector material collector material ( V vs. SCE ) (M ) (mm ) pH
Example Ti LiMn204 Zn TiO2 -1.50 LiCl (12 ) 3.1
107
Example Ti LiMn204 Zn Li NaTi5Nb014 -1.75 LiCl (12) 3.1
108
Comparative Ti LiMn204 Ti TiO2 -1.50 LiCl (12) 3.1
Example 103
Comparative Ti LiMn204 Ti LizNaTigNb014 -1.75 LiCl (12) 3.1
Example 104

20
suppressed, so that the capacity retention ratio and the The following table 10 summarizes the conditions of the
charge - and -discharge efficiency were reduced . initial charge and discharge of the battery for evaluation
As shown in Table 8 , in any of the negative electrodes in manufactured in each of Examples 107 and 108, and Com
Examples 101 to 106 , the thickness of the covering layer parative Examples 103 and 104.
formed on the negative electrode active material was small- 25
est, and the thickness of the covering layer formed on the TABLE 10
negative electrode current collector was largest. It is con Charge - and -discharge conditions
sidered that this is because in surface covering by electrode
position , coating of a material having high conductivity had 30 Negative Negative
preferentially progressed . electrode
potential
electrode
potential
Next, the results of investigating a lithium ion secondary Current reached reached
battery using various titanium -containing oxides as the Temperature density at charge at discharge
negative electrode active materials are shown in Examples (° C .) (mA /cm²) (V vs. SCE ) ( V vs. SCE )
107 and 108 , and Comparative Examples 103 and 104 . 35 Example 25 4.0 -1.6 -1.3
107
Example 107 Example 25 4.0 -1.6 -1.3
108
A battery for evaluation was produced similarly to Comparative 25 4.1 -1.6 -1.3
Example 103
Example 101 except that monoclinic titanium dioxide ( TiO2 40 Comparative 25 4.1 -1.6 -1.3
( B )) was used as a negative electrode active material. Example 104
Example 108
(Constant-Current Charge - and -Discharge Test)
A battery for evaluation was produced similarly to For each of the batteries for evaluation manufactured in
Example 101 except that Li NaTisNbO14 was used as a 45 Examples 107 and 108 and Comparative Examples 103 and
negative electrode active material. 104 , the capacity retention ratio after 20 cycles and the
charge -and-discharge efficiency after 20 cycles were
Comparative Example 103 obtained similarly to Examples 101 to 106 , and Comparative
Examples 101 and 102. The following table 11 summarizes
A battery for evaluation was produced similarly to 50 the obtained results .
Example 101 except that a Ti foil was used as a negative
electrode current collector, and monoclinic titanium dioxide TABLE 11
( TiO2(B )) was used as a negative electrode active material. Capacity retention rate Charge -and-discharge
Comparative Example 104 55 after 20 cycles efficiency after 20 cycles
(% ) (% )
A battery for evaluation was produced similarly to Example 86.5 82.3
Example 101 except that a Ti foil was used as a negative 107
Example 80.4 78.5
electrode current collector, and Li,NaTisNb014 was used as 60 108
a negative electrode active material. Comparative 65.0 77.4
The following table 9 summarizes , for each of Examples Example 103
Comparative
107 and 108 and Comparative Examples 103 and 104 , the Example 104
68.0 71.2
material of the current collector and the composition of the
active material in each of the positive and negative elec
trodes used in the manufacturing of the battery for evalua- 65 ( Analysis of Composition and Thickness of Covering Layer )
tion , the composition and concentration of the electrolyte For each of the batteries for evaluation manufactured in
used in the electrolytic solution , the additive added to the Examples 107 and 108 and Comparative Examples 103 and
 US 10,727,540 B2
53 54
104, the composition and layer thickness of the covering and 108, the negative electrode included the covering layer,
layer in each member in the negative electrode were ana while on the other hand , in Comparative Examples 103 and
lyzed similarly to Examples 101 to 106 , and Comparative 104, the negative electrode included no covering layer. Thus,
Examples 101 and 102. As a result, it was found that in it is considered that a reaction between each member (the
Examples 107 and 108 , the covering layer including a Zno 5 agent negative electrode active material, the electro -conductive
, and the negative electrode current collector ) in the
phase was present in each of the negative electrode active negative
material, the electro -conductive agent, and the negative discharge electrode could
and the electrolytic solution and self
not be suppressed , so that the capacity
electrode current collector. In Examples 107 and 108 , it is retention ratio and the charge -and -discharge efficiency were
considered that since as in Example 101, a Zn foil was used 10 reduced .
as the negative electrode current collector, and titanium Examples in which batteries for evaluation were manu
dioxide and Li,NaTisNb014 were respectively used as the factured using various additives in electrolytic solutions are
negative electrode active materials, so that the negative shown below .
electrode potential reached -1.6 V (vs. SCE ) in the initial 15
charge as shown in Table 6 , and therefore , the covering layer Example 109
including the ZnO phase was formed due to zinc eluted from
the Zn foil. A battery for evaluation was produced similarly to
On the other hand , in both Comparative Examples 103 Example 101 except that a Ti foil was used as a negative
and 104 , the formation of the covering layer could not be 20 electrode current collector, and 20 mM of InClz and 10 mM
confirmed in any of the negative electrode active material, of saccharin sodium salt as additives were added to an
the electro -conductive agent, and the negative electrode electrolytic solution .
current collector. In Comparative Examples 103 and 104 , it
is considered that although the negative electrode potential Example 110
reached -1.6 V (vs. SCE) in the initial charge by using the 25
negative electrode active material similar to that of A battery for evaluation was produced similarly to
Examples 107 and 108 , respectively , since an element, Example 101 except that a Ti foil was used as a negative
which may serve as the constituent element of the covering electrode current collector, and 20 mM of PbCl2 and 10 mM
layer, was not included in either of the negative electrode of saccharin sodium
and the electrolytic solution as in Comparative Example 30 electrolytic solution . salt as additives were added to an
101, no covering layer was formed .
The following Table 12 summarizes , for each of the Example 111
negative electrode active material, the electro -conductive
agent, and the negative electrode current collector included
in the negative electrode in the battery for evaluation in each 35 A battery for evaluation was produced similarly to
of Examples 107 and 108 and Comparative Examples 103 Example 101 except that a Ti foil was used as a negative
and 104 , the component of the covering layer ( composition electrode current collector, and 10 mM of PbCl2, 10 mM of
of a confirmed phase ), the abundance ratio between the InC1z, and 10 mM of saccharin sodium salt as additives were
constituent elements in the covering layer, the thickness of added to an electrolytic solution .
the covering layer, and the cover ratio of the covering layer The following table 13 summarizes, for each of Examples
on the surface . 109 to 111, the material of the current collector and the
TABLE 12
Negative electrode active material Electro -conductive agent Negative electrode current collector
Abun Abun Abun
dance dance dance
ratio of ratio of ratio of
Component constituent Thick Cover Component constituent Thick Cover Component constituent Thick Cover
of covering elements ness ratio of covering elements ness ratio of covering elements ness ratio
layer (at % ) (nm ) (% ) layer (at % ) (nm ) (% ) layer (at % ) (nm ) (% )
Example Zno Zn (49 % ), 15 36 Zno Zn ( 47 % ), 25 21 Zno Zn (47 % ), 3000 99
107 O (51 % ) O (51 % ) O (53 % )
Example Zno Zn (55 % ), 24 38 Zno Zn (53 % ), 38 19 Zno Zn (47 % ), 3000 99
108 O (45 % ) O (47 % ) O (53 % )
Comparative — -
Example
103
Comparative
Example
104

60

As shown in Table 11, as compared with the batteries for composition of the active material in each of the positive and
evaluation manufactured in Examples 107 and 108 , in the negative electrodes used in the manufacturing of the battery
batteries for evaluation manufactured in Comparative for evaluation , the composition and concentration of the
Examples 103 and 104 , both of the capacity retention ratio 65 electrolyte used in the electrolytic solution , the additive
after 20 cycles and the charge-and -discharge efficiency after added to the electrolytic solution and concentration thereof,
20 cycles were low . As described above, in Examples 107 and pH of the electrolytic solution.
 US 10,727,540 B2
55 56
TABLE 13
Negative electrode
Li insertion /extraction
Positive electrode potential Electrolytic solution
Current Active Current Active of active material Electrolyte Additive
collector material collector material ( V vs. SCE ) (M ) (mm ) pH
Example Ti LiMn204 Ti Li Tig012 -1.52 LiCl (12 ) InCl3 (10 ) 2.9
109 saccharin ( 10 )
Example Ti LiMn204 Ti Li Tis012 -1.52 LiCl (12 ) PbCl2 (20 ) 2.8
110 saccharin (10 )
Example Ti LiMn204 Ti Li Tig012 -1.52 LiCl ( 12) PbCl2 (20 ) 2.8
111 InC13 ( 10 )
saccharin ( 10 )

The following table 14 summarizes the conditions of the TABLE 15 - continued

initial charge and discharge of the battery for evaluation Capacity retention rate Charge- discharge efficiency
manufactured in each of Examples 109 to 111 . 20 after 20 cycles after 20 cycles
(% ) (% )
TABLE 14
Example 96.4 904
Charge-and -discharge conditions 111

Negative Negative
electrode electrode 25 ( Analysis of Composition and Thickness of Covering Layer )
potential potential For each of the batteries for evaluation manufactured in
Current reached reached Examples 109 to 111, the composition and layer thickness of
Temperature density at charge at discharge the covering layer in each member in the negative electrode
(° C .) (mA/cm ) ( V vs. SCE) ( V vs. SCE ) were analyzed similarly to Examples 101 to 108 and Com
Example
30 parative Examples 101 to 104.
109
25 4.0 -1.6 -1.3
As a result, in Example 109 , a covering layer including an
Example 25 4.2 -1.6 -1.3 indium oxide (In2O3 , InO ) phase was formed in each of the
110 members. In Example 109, InClz as an additive was con
Example 25 4.0 -1.6 -1.3 tained in the electrolytic solution . It is considered that the
111 35 covering layer including the indium oxide phase was formed
due to InCiz.
In Example 110 , a covering layer including a PbO2phase
(Constant- Current Charge -and -Discharge Test) was formed in each of the members . In Example 110 , PbCl2
For each of the batteries for evaluation manufactured in
as an additive was contained in the electrolytic solution . It
40 is considered that the covering layer including the PbO2
Examples 109 to 111, the capacity retention ratio after 20 phase was formed due to PbCl2.
cycles and the charge -and -discharge efficiency after 20 In Example 111, a covering layer including an In203
cycles were obtained similarly to Examples 101 to 108 and phase and a PbO2 phase was formed in each of the members .
Comparative Examples 101 to 103. The following table 15 In Example 111 , PbCl, and InCiz as additives were con
summarizes the obtained results . tained in the electrolytic solution . It is considered that the
45 covering layer including the In2O3 phase and the PbO2 phase
TABLE 15 was formed due to those additives .
The following Table 16 summarizes, for each of the
Capacity retention rate Charge -discharge efficiency negative electrode active material, the electro -conductive
after 20 cycles after 20 cycles agent, and the negative electrode current collector included
(% ) (% ) 50 in the negative electrode in the battery for evaluation in each
Example 89.8 83.2 of Examples 109 to 111 , the componentof the covering layer
109 (composition of a confirmed phase ), the abundance ratio
Example 97.1 90.0 between the constituent elements in the covering layer, the
110 thickness of the covering layer, and the cover ratio of the
covering layer on the surface .
TABLE 16
Negative electrode active material Electro -conductive agent Negative electrode current collector
Abun Abun Abun
dance dance dance
ratio of ratio of ratio of
Component constituent Thick Cover Component constituent Thick Cover Component constituent Cover
of covering elements ness ratio of covering elements ness ratio of covering elements Thickness ratio
layer (at % ) (nm ) ( % ) layer (at % ) (nm ) ( % ) layer ( at % ) ( nm ) (% )
Example In203 In (43 % ), 8 32 Ino In (41 % ), 12 24 In203 In (39 % ), 25 98
109 O (57 % ) O (59 % ) O (61 % )
 US 10,727,540 B2
57 58
TABLE 16 - continued
Negative electrode active material Electro - conductive agent Negative electrode current collector
Abun Abun Abun
dance dance dance
ratio of ratio of ratio of
Component constituent Thick Cover Component constituent Thick Cover Component constituent Cover
of covering elements ness ratio of covering elements ness ratio of covering elements Thickness ratio
layer (at % ) (nm ) ( % ) layer (at % ) (nm ) (% ) layer ( at % ) ( nm ) (% )
Example PbO , Pb (35 % ), 12 40 PbO2 Pb (37 % ), 15 22 PbO2 Pb (40 % ), 35 98
110 O (65 % ) O (63 % ) O (60 % )
Example In 03 In ( 24 % ), 15 42 In2O3 In ( 22 % ), 15 26 In203 In (20 % ), 39 99
111 PbO2 Pb (11% ) PbO2 Pb (13 % ) PbO2 Pb (12 % )
O (65 % ) O (65 % ) O (68 % )
15
The result of investigating secondary batteries using vari electrode current collector, and Nb TiO , was used as a
ous electrode active materials is shown in Examples 112 to negative electrode active material.
114 and Comparative Examples 105 to 107.
Comparative Example 106
Example 112 20

A battery for evaluation was produced similarly to A battery for evaluation was produced similarly to
Example 101 except that Nb TiO , was used as a negative Example 101 except that a Ti foil was used as a negative
electrode active material. electrode current collector , and LiFePo4 was used as a
25 positive electrode active material.
Example 113 Comparative Example 107
A battery for evaluation was produced similarly to A battery for evaluation was produced similarly to
Example 101 except that LiFePo4 was used as a positive
electrode active material. 30 Example 101 except that a Ti foil was used as a negative
electrode current collector, and LiC002 was used as a
Example 114 positive electrode active material .
The following table 17 summarizes , for each of Examples
A battery for evaluation was produced similarly to 112 to 114 and Comparative Examples 105 to 107, the
Example 101 except that LiC002 was used as a positive 35 material of the current collector and the composition of the
electrode active material. active material in each of the positive and negative elec
trodes used in the manufacturing of the battery for evalua
Comparative Example 105 tion , the composition and concentration of the electrolyte
used in the electrolytic solution , the additive added to the
A battery for evaluation was produced similarly to electrolytic solution and concentration thereof, and pH of
Example 101 except that a Ti foil was used as a negative the electrolytic solution.
TABLE 17
Negative electrode
Li insertion /extraction
Positive electrode potential Electrolytic solution
Current Active Current Active of active material Electrolyte Additive
collector material collector material ( V vs. SCE) (M ) (MM ) pH
Example LiMn204 Zn Nb Tion -1.64 iCl ( 12 ) 3.1
112
Example Ti LiFePO4 Zn LidTig012 -1.60 LiCl (12 ) 3.1
113
Example Ti LiCO2 Zn LifTis012 -1.60 LiCl (12) 3.1
114
Comparative Ti LiMn204 Ti Nb Ti07 -1.64 LiCl (12) 3.1
Example 105
Comparative Ti LiFePO4 Ti LidTig012 -1.60 LiCl (12) 3.1
Example 106
Comparative Ti LiCO2 Ti Li Tig012 -1.60 LiCl (12 ) 3.1
Example 107
 US 10,727,540 B2
59 60
The following table 18 summarizes the conditions of the TABLE 19 - continued
initial charge and discharge of the battery for evaluation Charge -and-discharge
manufactured in each of Examples 112 to 114 and Com Capacity retention rate
after 20 cycles efficiency after 20 cycles
parative Examples 105 to 107. 5
(% ) (% )
TABLE 18 Comparative 65.2 76.9
Example 107
Charge - and- discharge conditions
Negative Negative (Analysis of Composition and Thickness of Covering Layer )
electrode electrode 10 For each of the batteries for evaluation manufactured in
potential potential Examples 112 to 114 and Comparative Examples 105 to
Current reached reached 107, the composition and layer thickness of the covering
Temperature density at charge at discharge layer in each member in the negative electrode were ana
(° C .) ( / cm²)
mA (V vs. SCE ) ( V vs. SCE ) lyzed similarly to Examples 101 to 111 and Comparative
Example 25 4.0 -1.8 -1.4 15 Examples 101 to 104. As a result, in Examples 112 to 114 ,
112 it was found that the covering layer including a ZnO phase
Example 25 3.9 -1.6 -1.4 was present in each of the negative electrode active material ,
113
Example 25 3.8 -1.6 -1.3 the electro - conductive agent, and the negative electrode
114 current collector. In Examples 112 to 114 , it is considered
Comparative 25 3.8 -1.8 -1.4 20 that since as in Example 101 , a Zn foil was used as the
Example 105
Comparative
negative electrode current collector, and niobium titanium
Example 106
25 3.9 -1.6 -1.4 (Nb Ti07) or spinel type lithium titanate oxide (Li_Ti 012)
Comparative 25 3.8 -1.6 -1.3 was used as the negative electrode active material, so that
Example 107 the negative electrode potential reached -1.6 V to -1.8 V
(vs. SCE ) in the initial charge as shown in Table 18 , and
25 therefore, the covering layer including the ZnO phase was
(Constant- Current Charge -and -Discharge Test) formed due to zinc eluted from the Zn foil.
For each of the batteries for evaluation manufactured in On the other hand , in any of Comparative Examples 112
Examples 112 to 114 and Comparative Examples 105 to to 114 , the formation of the covering layer could not be
107, the capacity retention ratio after 20 cycles and the confirmed in any of the negative electrode active material,
charge-and -discharge efficiency after 20 cycles were 30 the electro -conductive agent, and the negative electrode
current collector. In Comparative Examples 112 to 114 , it is
obtained similarly to Examples 101 to 111 and Comparative considered
Examples 101 to 104. The following table 19 summarizes reached -1.6thatV toalthough -1.8 V
the negative electrode potential
( vs. SCE ) in the initial charge by
the obtained results . respectively using the negative electrode active material
TABLE 19 35 similar to that in Examples 112 to 114 , since an element,
which may serve as the constituent element of the covering
Capacity retention rate Charge -and -discharge layer, was not included in either of the negative electrode
after 20 cycles efficiency after 20 cycles and the electrolytic solution as in Comparative Example
(% ) (% ) 101, no covering layer was formed .
Example 76.2 75.3 40 The following Table 20 summarizes, for each of the
112 negative electrode active material, the electro -conductive
Example 85.5 81.2 agent, and the negative electrode current collector included
113 in the negative electrode in the battery for evaluation in each
Example 86.8 81.8 of Examples 112 to 114 and Comparative Examples 105 to
114
Comparative 66.4 69.2
107 , the componentof the covering layer (composition of a
Example 105 45 confirmed phase ), the abundance ratio between the constitu
Comparative 62.0 70.6 ent elements in the covering layer, the thickness of the
Example 106 covering layer, and the cover ratio of the covering layer on
the surface .
TABLE 20
Negative electrode active material Electro -conductive agent Negative electrode current collector
Abun Abun Abun
dance dance dance
ratio of ratio of ratio of
Component constituent Thick Cover Component constituent Thick Cover Component constituent Thick Cover
of covering elements ness ratio of covering elements ness ratio of covering elements ness ratio
layer (at % ) (nm ) (% ) layer ( at % ) ( nm ) (% ) layer (at % ) (nm ) (% )
Example Zno Zn (53 % ), 32 52 Zno Zn (53 % ), 37 18 Zno Zn (47 % ), 3000 97
112 O (47 % ) O (47 % ) O (53 % )
Example Zno Zn (51 % ), 22 40 Zno Zn (50 % ), 38 19 Zno Zn (48 % ), 3000 99
113 O (49 % ) O (50 % ) O (52% )
Example Zno Zn (52% ), 23 37 Zno Zn (55 % ), 35 20 Zno Zn (49 % ), 3000 98
114 O (48 % ) O (45 % ) O (51% )
Comparative - -
Example
105
 US 10,727,540 B2
61 62
TABLE 20 -continued
Negative electrode active material Electro -conductive agent Negative electrode current collector
Abun Abun Abun
dance dance dance
ratio of ratio of ratio of
Component constituent Thick Cover Component constituent Thick Cover Component constituent Thick Cover
of covering elements ness ratio of covering elements ness ratio of covering elements ness ratio
layer (at % ) (nm ) (% ) layer (at % ) (nm ) layer (at % ) (nm ) (% )
Comparative
Example
106
Comparative — —
Example
107

As shown in Table 19, as compared with the battery for and are not intended to limit the scope of the inventions .
evaluation manufactured in Example 112 , in the battery for Indeed , the novel embodiments described herein may be
evaluation manufactured in Comparative Example 105 , both embodied in a variety of other forms; furthermore, various
of the capacity retention ratio after 20 cycles and the 20 omissions, substitutions and changes in the form of the
charge-and -discharge efficiency after 20 cycles were low . embodiments described herein may be made without depart
Similarly, as compared with the batteries for evaluation ing from the spirit of the inventions. The accompanying
manufactured in Examples 113 and 114 , in the batteries for claims and their equivalents are intended to cover such
evaluation manufactured in Comparative Examples 106 and forms or modifications as would fall within the scope and
107, both of the capacity retention ratio after 20 cycles and 25 spirit of the inventions .
the charge -and -discharge efficiency after 20 cycles were What is claimed is :
low . As described above, in Examples 112 to 114 , the 1. A secondary battery comprising:
negative electrode included the covering layer , while on the a positive electrode;
other hand , in Comparative Examples 105 to 107 , the 30 a negative electrode comprising a titanium - containing
negative electrode included no covering layer. Thus, it is oxide and zinc as metal, at least one compound of
considered that a reaction between each member (the nega additive element, or both the zinc as metal and the
tive electrode active material, the electro - conductive agent, compound of additive element, the titanium -containing
and the negative electrode current collector ) in the negative oxide comprising one or more selected from the group
electrode and the electrolytic solution and self-discharge 35 consisting of titanium oxide represented by a general
could not be suppressed , so that the capacity retention ratio formula Li TiO2 where Osxsl, lithium titanium oxide
and the charge -and -discharge efficiency were reduced . represented by a general formula Lis+ , Ti,012 where
According to at least one of the above embodiments , since -1sxs3 , lithium titanium oxide represented by
the secondary battery includes the negative electrode, con Li2+ xTizo , where -1sxs3, lithium titanium oxide rep
taining titanium -containing oxide and at least one kind of 40 resented by Li1 +xTi204 where Osxs1, lithium titanium
element selected from the group consisting of B , P , Al, La, oxide represented by Li1.1 +xT11.804 where Osxsl,
Zr, Ge, Zn, Sn , Ga, Pb , In , Bi, and T1, and the electrolyte lithium titanium oxide represented by Li1.07 +xTi1.8604
containing lithium ions and a solvent containing water , the where Osxsl , niobium oxide represented by
secondary battery, battery module and battery pack excellent Li, TIM ,Nb2180720 where Osas5 , Osbs0.3 , Osßs0.3 ,
in cycle life performance , storage performance, and large 45 Osos0.3 , and M is at least one selected from the group
current discharge performance, and the vehicle including the consisting of Fe, V , Mo, and Ta , and sodium niobium
battery pack can be provided . titanium oxide represented by a general formula
According to at least one embodiment and Example Liz + Na-„ M1, Ti_v_2Nb M2,014-8 where Osvs4 ,
described above , a secondary battery including a positive O < w < 2 , Osx < 2 , 0 < ys6 , Osz < 3 , -0.5sds0.5 , Mi
electrode, a negative electrode , and an electrolytic solution 50 includes at least one selected from Cs, K , Sr, Ba, and
is provided . The negative electrode includes a current col Ca, and M2 includes at least one selected from Zr, Sn ,
lector and a negative electrode active material including V , Ta , Mo, W , Fe , Co, Mn, and Al, and the compound
titanium -containing oxide. At least one of the current col of additive element being at least one selected from the
lector and the negative electrode active material includes , on group consisting of boron oxide, alumina, zirconium
at least a portion of a surface thereof, a covering layer 55 oxide, germanium oxide, zinc oxide, lead oxide, zinc
including at least one kind of element selected from the hydroxide, Lis+zALaz- M2012 where A is at least one
group consisting of Zn , In , Sn , Pb , Hg, Cu, Cd , Ag, and Bi. element selected from the group consisting of Ca, Sr,
The electrolytic solution includes an aqueous solvent and an and Ba, Mis Nb and /or Ta , and x is Osxs2 ,
electrolyte . According to this constitution , safety is high LizM2-xL2012 where M is Ta and/or Nb, L is Zr, and x
because the electrolytic solution including the aqueous sol- 60 is Osxs2, Li7-3, A1, LazZr2012 where x is Osxs0.3 ,
vent is used , and self-discharge is suppressed ; therefore, it is Li- La, Zr,0,2, Liz, La2/3-, TiO where 0.05sxs0.15 ,
possible to provide a secondary battery, a battery module, Li .31i1.7A10.3 (PO4)3, an oxide solid electrolyte having
and a battery pack excellent in charge -and -discharge effi a y -Li3PO4 crystal structure , a Zn alloy, a Bi— In — Pb
ciency and charge -and -discharge cycle life and a vehicle based alloy, a Bi - In - Ca-based alloy , and a Bi - In
including the battery pack . 65 Al alloy ; and
While certain embodiments have been described , these an electrolyte comprising lithium ions and water as a
embodiments have been presented by way of example only, solvent.
 US 10,727,540 B2
63 64
2. The secondary battery according to claim 1, 13. The secondary battery according to claim 12 , wherein
wherein the electrolyte further comprises zinc ions. the negative electrode active material includes the covering
3. The secondary battery according to claim 1, layer on at least a portion of the surface thereof.
wherein the negative electrode comprises particles of the 14. The secondary battery according to claim 12, wherein
titanium - containing oxide and a covering member cov 5 the negative electrode further comprises an electro -conduc
ering at least a portion of surfaces of the particles and tive agent, and the current collector, the negative electrode
comprising the at least one kind of element. active material, and the electro -conductive agent each
4. The secondary battery according to claim 1, include the covering layer on at least a portion of a surface
wherein the electrolyte further comprises an anion com 10 thereof.
prising at least one selected from the group consisting 15. The secondary battery according to claim 14 , wherein
of a chlorine ion ( C1" ), a hydroxide ion (OH-), a sulfate for each of the current collector, the negative electrode
ion (SO42-) , and a nitrate ion (NO3 ). active material, and the electro -conductive agent, 10 % or
5. The secondary battery according to claim 1, more to 100 % or less of a surface area thereof is covered
wherein the titanium -containing oxide comprises at least 15 with the covering layer.
one of the titanium oxide represented by the general 16. The secondary battery according to claim 12 , wherein
formula Li TiO2 (Osxsl) and the lithium titanium the covering layer has a thickness of 2 nm or more and 5 um
oxide represented by the general formula Li4 +xTi 012 or less and comprises at least one phase selected from the
(x is -1 < x < 3 ). group consisting of: a phase ofmetal comprising at least one
6. A battery module comprising the secondary battery 20 kind of element selected from the group consisting of Zn , In ,
according to claim 1 . Sn , Pb Hg, Cu , Cd , Ag, and Bi; a phase of alloy comprising
7. A battery pack comprising the secondary battery the at least one kind of element; a phase of oxide of the at
according to claim 1. least one kind of element; and a phase of hydroxide of the
8. The battery pack according to claim 7 , further com at least one kind of element.
prising an external power distribution terminal and a pro- 25 17. The secondary battery according to claim 12 , wherein
tective circuit. the negative electrode active material comprises at least one
9. The battery pack according to claim 7 , comprising a kind of compound selected from the group consisting of the
plural of the secondary batteries, the secondary batteries oxide of titanium , the lithium titanium oxide having the
being electrically connected in series , in parallel, or in spinel structure, the niobium titanium composite oxide rep
combination thereof. 30 resented by the general formula Ti - Mx+yNb2-07-8,
10. A vehicle comprising the battery pack according to wherein 0sx < 1, Osy < 1 , and M includes at least one selected
claim 7 . from Mg, Fe, Ni, Co, W , Ta, and Mo, and the orthorhombic
11. The vehicle according to claim 10 , type Na-containing niobium titanium composite oxide rep
wherein the battery pack is configured to recover a resented by the general formula Li2 +„Na2- „ MI,
regenerative energy of power of the vehicle . 35 Tig_y__Nb,M2_01478 wherein Osvs4, O < w < 2 , 0 < x < 2 ,
12. A secondary battery comprising: O < y < 6 , Osz < 3 , y + z < 6 , -0.55d50.5 , Mi is at least one
a positive electrode; element selected from the group consisting of Cs, K , Sr, Ba ,
a negative electrode comprising a current collector and a and Ca, and M2 is at least one element selected from the
negative electrode active material containing a tita group consisting of Zr, Sn, V , Ta, Mo, W , Fe, Co, Mn , and
nium -containing oxide, at least one of the current 40 Al.
collector and the negative electrode active material 18. The secondary battery according to claim 12 , wherein
including , on at least a portion of a surface thereof, a the electrolytic solution includes at least one kind of anion
covering layer including at least one kind of element selected from the group consisting of NO3-, Cl-, LiS04 ;
selected from the group consisting of Zn , In , Sn , Pb , SO , 2-, OH , [N (SO CF3) 21 "; [N (SO , F )21 ", and
Hg, Cu, Cd , Ag, and Bi, the titanium -containing oxide 45 [B (C204)2 ]
comprising at least one kind of compound selected 19. The secondary battery according to claim 12 , wherein
from the group consisting of oxide of titanium repre the positive electrode includes a positive electrode active
sented by Liz TiO2 wherein x is 0sxs1, lithium titanium material comprising at least one kind of compound selected
oxide having a spinel structure, lithium - titanium oxide from the group consisting of a phosphate compound having
having a ramsdellite structure, niobium - titanium oxide 50 an olivine structure and represented by a general formula
represented by Li, TiM , Nb2+80770 wherein Osas5 , Li_FePO4 wherein Osxsl, a lithium manganese composite
Osbs0.3 , Osßs0.3 , Osos0.3, and M is at least one oxide represented by a general formula Li Mn204 wherein
element selected from the group consisting of Fe, V, 0 <xsl, and a lithium cobalt composite oxide represented by
Mo, and Ta, niobium titanium composite oxide repre a general formula Li Coll , wherein 0 <xsl.
sented by a general formula Ti - M +, Nb2--07-5 , 55 20. A battery module comprising the secondary battery
wherein 0sx < 1 , Osy < 1, and M includes at least one according to claim 12 .
selected from the group consisting of Mg, Fe , Ni, Co , 21. A battery pack comprising the secondary battery
W , Ta, and Mo, and orthorhombic Na-containing nio according to of claim 12 .
bium titanium composite oxide represented by a gen 22. The battery pack according to claim 21, further
eral formula Li2+„Naz-„ M1, Ti6 -y- 2Nb,M2,014 +8 60 comprising an external power distribution terminal and a
wherein Osvs4 , 0 < w < 2 , 0 < x < 2, 0 < y < 6 , Osz < 3 , y + z < 6 , protective circuit .
-0.5sds0.5 , Mi is at least one element selected from 23. The battery pack according to claim 21, comprising a
the group consisting of Cs, K , Sr, Ba, and Ca , and M2 plural of the secondary batteries, the secondary batteries
is at least one element selected from the group con being electrically connected in series , in parallel, or in
sisting of Zr, Sn , V , Ta ,Mo, W , Fe, Co, Mn, and Al; and 65 combination thereof.
an electrolytic solution comprising an aqueous solvent 24. A vehicle comprising the battery pack according to
and an electrolyte . claim 21.
 US 10,727,540 B2
65 66
25. The vehicle according to claim 24 , 31. The secondary battery according to claim 12 ,
wherein the battery pack is configured to recover a wherein the electrolytic solution further comprises zinc
regenerative energy of power of the vehicle . ions, and the electrolyte comprises a lithium salt that
26. The secondary battery according to claim 1, wherein dissociates into Li ions and anions .
the electrolyte is an aqueous electrolyte . 5
32. The secondary battery according to claim 1 ,
27. The secondary battery according to claim 1 , wherein
the electrolyte further comprises a lithium salt, the lithium wherein the compound of additive element is selected
salt is comprised of anion species and the lithium ions , from the group consisting of alumina, zirconium oxide,
and the electrolyte comprises the water in an amountof
1 mol or more relative to 1 mol of the lithium salt.
zinc oxide, Li,LazZr2012, Li13T11.7A1, .3 (PO4)3,
28. The secondary battery according to claim 12 ,wherein 10 Liz.Ge.V0.404
the electrolytic solution comprises water, and the electro 33. The secondary battery according to claim 1 ,
lytic solution comprises the water in an amount of 1 wherein the zinc as metal and the compound of additive
mol or more relative to 1 mol of the electrolyte. element is comprised as particles mixed in the negative
29. The secondary battery according to claim 27 , 15
electrode or as a covering member covering the tita
wherein the electrolyte comprises an aqueous solution nium -containing oxide.
having a lithium ion concentration in the range of not 34. The secondary battery according to claim 12 ,
less than 2 mol/ L and not more than 10 mol/ L .
30. The secondary battery according to claim 28 , wherein the covering layer comprises at least one selected
wherein the electrolyte comprises a lithium salt that from the group consisting of ZnO , In2O3, Cu, Sno ,
dissociates into Li ions and anions, and the anions have 20 InO , and Pb02.
a concentration of 1 M to 10 M in the electrolyte .