Thermal materials, adhesives, sealants &

functional coatings for electric vehicles

LEAR, 30/03/2021
Matthias Brachmann, Business Development

Henkel's e-Mobility Solutions

AGENDA

1. Materials for Power Electronics

2. Circuit Board Protection

3. Thermal Potting Options:

Overview / Advantages & Limitations

4. TIM Potting:
OBC Application Example & New Developments for TIM Potting

5. Gasketing / Sealing Options

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HENKEL’S E-MOBILITY SOLUTIONS
KEY COMPONENTS FOR ELECTRIC VEHICLES
Battery System Power Electronics Electric Drive System

▪ Battery Cell ▪ Inverter ▪ Electric Motor

▪ Battery Module ▪ Onboard charger ▪ Electric Transmission
▪ Battery Pack ▪ DC/DC Converter ▪ Electric Drive Housing
▪ Battery Control Module
▪ 48 V for Mild Hybrid

Broad technology portfolio to increase efficiency, safety and reliability

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CUSTOMER USE-CASES
MATERIALS FOR POWER ELECTRONICS
Thermal Gap Pad
Module Sealing

4 1

Bergquist TGP 1000VOUS

Loctite SI 5970 BM 3
Thermal Gap Filler

Thermal Potting
2

Bergquist TGF 3600

Bergquist TLB 1400SL

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CIRCUIT BOARD
PROTECTION OPTIONS
▪ Potting
▪ Conformal coating
Product Lines ▪ Low Pressure Molding (Technomelt)
▪ Underfills
▪ Encapsulants (Glob top)

▪ Oxygen
▪ Moisture
▪ Heat & Cold
External ▪ Dirt
Environment ▪ Chemical Exposure

▪ Enhance mechanical
strength
Protection
▪ Enhance assemblies
ability to withstand
vibration and Mechanical Electrical
shock Reinforcement Insulation
▪ Propriety design
protection

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POTTING MATERIAL OPTIONS
CHEMISTRIES – COMPARISON OF GENERIC PROPERTIES

Characteristics Epoxy Polyurethane Silicone Polyacrylates

High
Service temperature Moderate Very high Moderate
-40°C up to 160 –
(°C) -40°C up to 125°C -40°C up to 230-260°C -55°C up to 140°C
180°C
Thermal conductivity
0.2 (*) 0.2 (*) 0.2 (*) 0.2(*)
(W/mK)
Tg (°C) High Medium / low Very low Medium / low
Hardness (shore) Rigid Soft Soft Soft
Very flexible
Flexibility Brittle Flexible (also low temp) Flexible
(-50 / 200°C)
Stress High Low Very low Low
Water glycol: poor
Chemical resistance Excellent Good Poor
Oil: good
Adhesion Very good Good Poor Good
Cost Medium Low High High

(*) depending on the addition of filler; value is referring to an unfilled system

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POTTING MATERIAL OPTIONS
CHEMISTRIES - PERFORMANCE COMPARISON

Silicone (SR) High

250 ℃
▪ Up to about 250℃
▪ Most flexible
Silicone
200 ℃
Epoxy (ER)
▪ Generally below 180℃
▪ Greatest mechanical strength

Flexibility
150℃ Urethane

Urethane (UR)
▪ Below 125℃
100℃ ▪ Generally “in between” epoxies
and silicones for mechanical Epoxy
strength and flexibility

Working Low Mechanical Strength High

Temperature
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POTTING IN POWER CONVERSION & E-DRIVE
THERMAL POTTING MATERIAL OPTIONS

“Soft” Silicone “Hard” Epoxy

Typical Application Typical Application

▪ Power Electronics, e.g. OBC ▪ Stator Potting of E-Motor
▪ Th. Conductivity 1.0 – 1.5 W/m.K ▪ Th. Conductivity >1.4 W/m.K
▪ Weight >0.5 kg ▪ Weight 1.5-2.0 kg per stator
▪ Trend: Weight reduction ▪ Trend: Improve heat dissipation

Pro’s & Con’s Pro’s & Con’s

✓ High flexibility, low thermal stress ✓ High mechanical strength for protection
✓ Low shrinkage during cure of Cu-windings
✓ Fast curing speed ✓ Excellent adhesion
✓ Excellent heat resistance up to 200 °C ✓ Stabil electrical properties
− Low adhesion to substrate (e.g., aluminum), ✓ High Tg, Low CTE material options
risk of delamination ✓ Heat resistant up to 180 °C (class H)
− Pt catalyst poisoning risk ✓ Good oil resistance
− Low mechanical stability − Risk of cracking in thermal cycle tests
− Poor el. insulation after 85C/85%RH aging − Requires long and hot thermal curing process
− Poor oil resistance
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CUSTOMER USE-CASES
PRACTICAL REFERENCE IN LARGE-SCALE PRODUCTION
OBC THERMAL POTTING Loctite SI 5631 Tier1
Approved

Chemistry 2-Part Silicone,

Fast dispensable and Type no cure by-products
self levelling product
1.0 W/m.K Thermally
Technology Conductive Potting
Compound
1 : 1 mixing ratio (vol.),
work life >60 min @ RT Heat cure
Curing
30 min @ 80 °C or
Mechanism
15 min @ 100 °C

Applied in >100.000 High temperature and

OBC annually Performance crack resistance. No
filler settlement at RT

Reliable Thermal and Mechanical Protection of Onboard Battery Chargers

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POTTING IN POWER CONVERSION & E-DRIVE
SILICONES FOR POWER ELECTRONICS
LOCTITE SI 5631 LOCTITE SI 5643 LOCTITE SI 5632
(Henrico)
Remark Running in serial production Very soft TIM potting for Lower density TIM potting
sensitive components
Mixing ratio by vol. 1:1 1:1 1:1

Thermal Conductivity 1.0 W/mK 1.5 W/mK >1.5 W/mK

Viscosity @25°C 5000 mPa.s 6000 mPa.s 5300 mPa.s

Working Life @25°C > 60 min 45-60 min > 60 min

Curing @ 80°C 30 min 15 min 30 min

Specific Weight 1.63 g/cm3 2.67 g/cm3 1.99 g/cm3

Hardness 28 Shore A 4-7 Shore A 40 Shore A

Volume resistivity 1 x 1013 Ohm.cm 1 x 1014 Ohm.cm > 1 x 1013 Ohm.cm

REACH & RoHS Compliant Compliant Compliant

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RECENT MARKET INTRODUCTION
NEW: 1K POLYACRYLATE

LOCTITE AA 5831M
▪ Soft, flexible, low modulus compound for encapsulation and potting
▪ Requires UV cure and moisture cure for full performance
▪ Good chemical resistance against Automated Transmission Fluid (ATF) and Engine Oil

Benefits Application Examples & Value Enhancement

▪ Single component, no mixing 20 mm depth
▪ Fast fixation by UV light cure by UV
▪ Good adhesion by moisture light: Ideal for
cure potting of
▪ Very low permeability of engine connectors /
sensors that
oil and ATF are exposed
▪ Low thermal stress to oil
▪ No silicone contamination /
foaming of engine oil

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NEW DEVELOPMENT PROJECT
NEW: LOW VISCOSITY 2K PU

TEROSON PU U333/U102
▪ 2K heat accelerated cure product
▪ Low viscosity potting material based on Teroson PU U137S / U102

Benefits Application Examples

▪ Low visosity (1.300 mPa.s)
▪ Service temperature
-40 to 130°C
▪ Good adhesion with cohesive
failure on many substrates
▪ Mixing ratio 100 : 50
▪ Soft, low stress (shore A 40)
▪ Low temperature capable
(Tg < -50 °C)
Door Handle Sensor Tire Pressure Sensor

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 In development
PRODUCTS IN DEVELOPMENT Formulation not fixed yet

NEW: 1K SILICONE – NON-CORROSIVE

LOCTITE SI 5035
▪ 1K, non-corrosive, high adhesion, LED or UV/ moisture cure potting
▪ Similar performance characteristics as LT SI 5091 or SI 5031 (both corrosive), better adhesion

Benefits Application Examples & Value Enhancement

▪ Quick LED resp. UV cure in
<30 sec. possible
▪ Able to high pressure leak test
parts right after UV cure
▪ Small dispensing and curing
equipment footprint

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CUSTOMER USE-CASES
MATERIALS FOR POWER ELECTRONICS
Thermal Gap Pad
Module Sealing

4 1

Bergquist TGP 1000VOUS

Loctite SI 5970 BM 3
Thermal Gap Filler

Thermal Potting
2

Bergquist TGF 3600

Bergquist TLB 1400SL

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Formed-In-Place Gasketing
LOCTITE SI 5970 - THREE VARIATIONS

▪ SI 5970 BK (Black) is long time approved in many OEM

and Tier1 applications
▪ NEW SI 5970 BM (Bubble Minimized) improves the
curing in tongue-and-grove gasket designs
▪ NEW SI 5970C (Fast Cure) shortens skin over time from
25 to 20 minutes
▪ One-component, no harm for electronics
▪ High elongation with excellent adhesion to metals
and plastics
▪ Excellent long-term automotive fluid resistance, e.g. oil
▪ Blow-Out resistance (1 mm gap, 60 s): >3.5 psi

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Formed-In-Place Gasketing
LOCTITE AA 5820

▪ Superior hot oil resistant flexible Polyacrylate

▪ Gap Filler compatible
▪ 1K, Room Temperature Cure Material
▪ High elongation (> 175 %) with excellent adhesion
to metals and plastics
▪ Thermal resistance up to 150 °C
▪ Ability to combine multiple substrates
▪ Excellent chemical resistance against hydrocarbons
(oil, ATF, fuel)
▪ No foaming of engine oil
▪ No cure-inhibition of Henkel Gap Filler Technologies
▪ Meets high demands of thermal and chemical resistance, e.g. in
electrical oil pump applications

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Cured-In-Place Gasketing
LOCTITE AA 5884 AND AA 5891

New Polyacrylate Product Family

▪ With Loctite AA 5884 and AA 5891, Henkel provides the automotive industry
with a high-performance liquid dispensed compression gasket which can be
cured within seconds.
▪ Henkel’s dedicated technical resources provide assembly solutions on site to
improve your product and productivity.

Benefits Features
▪ Improved process reliability ▪ AA 5884: Excellent oil resistance
▪ Automatically pre-applied on part (up to 8X better than silicone)
▪ No tooling costs ▪ 10X better hydrocarbon permeation
▪ Fast process resistance than other liquid gaskets
▪ Adhesion to aluminum, cast iron, ▪ AA 5891: Excellent Coolant
stamped steel and plastics for resistance
transportation ▪ Does not promote oil foaming unlike
other sealants

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HENKEL & CUSTOMER NAME
LET’S PARTNER UP & DRIVE THE FUTURE TOGETHER

Matthias Brachmann
Business Development Manager
Matthias.Brachmann@Henkel.com

Battery
Henkel
Power conversion
Your full solution partner Electric drive

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 Driving the future.

Thank you!

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