Computer Simulations for Development of Electric Vehicles Thermal Management Systems.

Production of electric vehicles has been steadily increasing in recent years and is expected to witness a significant growth in near future. Lithium-Ion batteries are currently the preferred choice for energy storage due to their high energy density. Development of effective thermal management system is critical for the control of lithium-ion battery temperatures to extend battery life, maintain vehicle performance, and enhance battery and vehicle safety. During early stages of vehicle development, computer simulations are applied to predict any thermal issues that may affect the high voltage battery and vehicle performance. In this presentation, the development and application of extensive computer simulation process is presented. A transient thermal analysis model is developed where the effect of driving and soak conditions on battery temperature and performance are analyzed in a 3-D model. The analysis is coupled with customer duty cycle which includes typical city traffic, highway, and grade driving conditions. Battery transient temperature during driving conditions is analyzed to include effect of internal heat generation, external convection, and radiation. Therefore, the battery thermal profile throughout the year is developed. A thermal degradation model is applied to estimate the extent of thermal degradation and the remaining battery useful life for various geographic locations of hot ambient weather conditions.