Numerical Simulation of Cooling Plates/Tubes of BTMS of Electric Vehicles by Changing Internal Structure and Coolant Mass Flow Rate

The lithium-ion battery is the most common type of batteries in modern electric vehicles. During vehicle operation and battery charging, the temperature of the battery cells increases. The temperature of any battery must be controlled and maintained within a specified range to ensure maximum efficiency. Considering the overall thermal effect on the battery, a battery cooling system is of great importance in electric vehicles to maintain the temperature of the battery cells inside the battery pack. There are different types of systems for battery cooling, out of which the water cooled systems are very popular. They use a mixture of water and ethylene glycol to absorb heat from the battery cells. The coolant circulates through the tubes or cold plates surrounded by the cells to absorb the heat.

The paper involves the study of variation on temperature and pressure drop including overall thermal performance on the batteries by changing the internal structure. The temperature of battery packs have to be maintained within a range of 25 °C to 40 °C for better performance. This is done by changing the design of coolant channel and varying the mass flow rate of coolant in the tubes. Compressible fluid dynamics (CFD) analysis has been carried out on various designs and operating parameters. Heat source is defined on the cells as input thermal load to find out the temperature distribution/variation in the battery cells. From the findings, the total heat transfer and temperature distribution on the battery cell at different parameters has been predicted, followed by comparison of the results. Since the coolant flow rate is also varied, the pressure drop variation inside the tubes has also been studied. By changing the design of coolant channels, the improvement in the thermal performance of batteries is compared for different mass flow rate, fed as input. Hyper mesh has been used for the meshing and surface cleanup. STAR CCM+ has been used for CFD analysis and post processing of the results.