A numerical study on the performance of a thermal management system for a battery pack with cylindrical cells based on heat pipes

Thermal management system aims to control the operating temperature of power battery packs, which is of great significance for the safety and sustainability of the electric vehicle. In the present work, a novel thermal management system based on heat pipes is designed for a battery pack with cylindrical cells. The wave-shaped aluminum sleeves are employed to connect batteries with heat pipes and increase the contact area between them. Effects of the coolant flow rate, the length of heat pipe condenser section and the height of aluminum sleeve on thermal performance of the system are numerically investigated. The result shows that the coolant flow rate significantly influences the maximum temperature of the battery pack but affects the temperature uniformity slightly. When the battery pack discharges at 2 C, a coolant flow rate of 0.5 L.min(-1) is recommended. Increasing both the length of heat pipe condenser section and the height of aluminum sleeve can reduce the maximum temperature of the battery pack and improve the temperature uniformity. When the height of aluminum sleeve is above 60 mm, the temperature difference of the battery pack can be kept under 5 degrees C. Using aluminum sleeves with different heights can further improve the temperature uniformity of the battery pack while reducing the system weight.