CFD Analysis of a Prismatic Liquid Cooled Battery Pack to Optimize and Evaluate Pack Performance Under Variable Operating and Coolant Conditions

Heat generation from Lithium-ion batteries depends on its charge/discharge rates, SoC and temperature and hence varies considerably with vehicle driving conditions, DoD, ambient operating conditions and charging rate. To design and optimize the performance of a battery cooling system, it is desirable to study the steady and transient response of the system under variable operating and heat load conditions. In the present study, 3D CFD analysis has been performed to evaluate the performance of a prismatic liquid cooled Lithium Iron Phosphate battery pack under variable flow rate, inlet temperature and heat load conditions corresponding to different SoC and charge/discharge rates. An initial study is performed to validate the CFD model with experimental data and then the model is used to optimize the shape and size of the cold plate micro channels for improved heat transfer and reduced pressure drop. The varying heat load with SoC and charge/discharge rates is calculated from experimental data of LiFePO₄ cells available from literature and is then applied in the CFD model to evaluate the steady and transient response of the system for different coolant temperature and flow rate and determine the effectiveness of the system. This evaluation of battery temperature and effectiveness as a function of coolant parameters will help to determine the desired coolant flow rate and temperature for different operating and battery conditions. An optimized cold plate with operation at desired coolant conditions will have a profound effect on energy efficiency, battery life, safety, and reliability.