Fluid Flow through Helical Coil
Minal Wanjari, Pruthviraj Shinde, Atharva Suryawanshi
Department of Mechanical Engineering
Vishwakarma Institute of Technology, Pune - 411037
Abstract Battery Pack Structure and Cycle Temperature rises during the cell charge discharge process. The rise in
temperature depends upon the C- rate or the load condition and the
This project report presents a comprehensive simulation of the charge-
discharge cycles in a lithium-ion battery pack using Ansys Fluent. By
Dynamics atmospheric conditions.
The battery pack simulation focuses on two interconnected cells, • The temperature begins around 305 K and rises gradually.
analyzing two interconnected cells, the study focuses on key
electrochemical parameters and thermal performance, providing insights Cell 1 and Cell 2, linked by a conductive bus bar, typically made of • There’s a notable increase during the discharge phases, reaching
critical to optimizing battery design. The charge-discharge cycle is copper. Key cell properties include the active components—such approximately 315 K
modeled with varying load conditions and detailed timer schedules, as electrodes, electrolytes, and separators—which significantly • Temperature fluctuates, increasing during discharge and cooling slightly
enabling realistic simulation of energy transitions and heat generation. during charge phases, indicating heating due to discharge cycles.
impact the battery's energy density, power density, and cycle life.
This work aims to support the development of high-efficiency battery
systems suitable for applications such as electric vehicles and energy The cell capacity is 14.6 Ah and the working voltage range is 3 to Overall, each charge phase brings the voltage back up, while discharge
storage solutions. 4.3 volts. The active material, with a density of 20.92 g/cm³, plays phases cause drops. Higher discharge rates (e.g., 5C) lead to more
a vital role in energy transfer during charge and discharge cycles, significant voltage drops compared to lower rates, indicating higher power
draw impacts. The cycle highlights the battery’s voltage recovery during
while the electrical tabs conduct current, with their efficiency charging and the rapid depletion during discharging, particularly under high
Introduction dependent on the materials and surface area. loads.
The charge-discharge cycle is simulated using a precise timer
schedule to capture the sequence of energy flow. The cycle stages
Lithium-ion battery packs are integral to numerous modern include an initial discharge at 400 Watts for 100 seconds, followed
technologies, ranging by charging at 2C for 200 seconds, and subsequent phases
from electric vehicles to renewable energy storage. This report involving higher discharge rates (5C and 3C) and universal
explores the thermal and electrochemical behavior of a battery charging, simulating real-world conditions. Various electric load
pack during charge-discharge cycles using Ansys Fluent types—C rate, current, voltage, power, and external resistance—
simulation. The primary goal is to enhance the understanding are defined numerically (0-4) to ensure accuracy. Within the Ansys
of how varying load and environmental conditions affect setup, the cycle profile is configured through a text file specifying
battery performance, enabling designers to improve efficiency, load values over time, enabling the simulation to represent energy
safety, and longevity. transitions effectively. The model also incorporates energy
equations and the empirical Nernst-Planck model for
In this project, a two-cell battery pack connected via a electrochemistry, capturing current efficiencies, potential
conductive bus bar is simulated, with focus on the influence of distribution, and thermal dynamics as the battery undergoes Fig 1. Voltage vs time plot
active materials within the cells, including electrodes, charge-discharge cycles.
electrolytes, and separators. These materials play a pivotal role
in defining the energy density, power density, and cycle life of
the battery. The charge-discharge cycle is modeled with precise
Results
timing configurations that reflect realistic operating scenarios, The results include the voltage gain and drop and the temperature
providing valuable data on heat generation, potential variation during charge discharge process with respect to time.
distribution, and the overall thermal profile of the pack.
Through this analysis, the project contributes to optimizing 1. Discharge at 400 W for 100 seconds:
battery system designs for diverse applications. This is constant power discharge at 400W. The voltage starts at
approximately 3.9 V and drops slightly due to the initial discharge phase
Model and Materials and at the end of the phase the voltage suddenly increase this behaviour
is seen when the load is removed from battery pack.
2. Charge at 1C for 200 seconds:
This is constant charging process at the 1C rate. The voltage increases
steadily during this charging phase, reaching a peak around 4.2 V. This
rise indicates the battery’s response to the 1C charge rate. Fig 2. Temperature vs time Fig 3. Temperature
3. Discharge at 5C for 100 seconds: plot contour
The voltage drops significantly due to the high discharge rate (5C),
reflecting the rapid energy depletion from the battery. Conclusions
4. Charge at 6 A for 50 seconds: The simulation of a battery pack with two interconnected lithium-ion cells offers
Tab Material
The voltage recovers partially and increases during this short charging key insights into the electrochemical and thermal dynamics during charge-
period at 6 A, showing a quick recharge effect. discharge cycles. By analyzing the roles of active components—such as
electrodes, electrolytes, and separators—the study reveals their impact on
5. Discharge at 3C for 50 seconds:
energy density, power density, and cycle life.The defined charge-discharge cycle
Another dip in voltage occurs, although not as sharp as during the 5C stages, along with varying load conditions, effectively mimic real-world
Active Material discharge. This reflects a moderate discharge rate effect on voltage. operations, demonstrating how these factors influence performance.
6. Discharge at 200 W for 100 seconds: Incorporating energy equations and the empirical Nernst-Planck model
enhances the accuracy of current efficiencies and potential distributions. Overall,
The voltage continues to decrease gradually in response to the steady
this project advances the understanding of battery systems, supporting
200 W discharge. improvements in electric vehicles and renewable energy storage solutions.
Table 1. Model & Material Specification
Contact References
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TY-ME(C) 3. A. Rahman, X. Lin, Li-ion battery individual electrode state of charge and degradation monitoring using battery casing through auto curve matching for standard CCCV charging profile, Appl. Energy. 321 (2022) 119367.
4. Y.B. Tay, Y. Sim, J.K.K. Ang, M.I. Bin Patdillah, H.M. Chua, E.J.J. Tang, M. Srinivasan, N. Mathews, Upcycling end of life solar panels to lithium‐ion batteries via a low temperature approach, ChemSusChem. (2022).
Pruthviraj.shinde23@vit.edu
Contact: 8421173302
