Thermal characteristics of power battery pack with liquid-based thermal management

Thermal management of a battery system is critical for maintaining energy storage capacity, driving range, cell longevity and safety, while lithium-ion battery electric vehicles are becoming increasingly popular. Thermal management studies at battery pack level have a practical guiding significance for the exploration of appropriate battery thermal management schemes and strategies, which are seldom taken into account in the study of liquid-based battery thermal management system (BTMS). The effects of heat capacitance, heat source characteristics, ambient temperature and charge-discharge ratio on the thermal performance of liquid-based BTMS are experimentally investigated in this study. The results indicate that active battery thermal management should be adopted, and self-discharge heating might be an appropriate way to warm up power battery pack uniformly. In the charging and discharging process of the battery, the temperature uniformity of the battery at 45 degrees C is better than that at 25 degrees C. What's more, during charging and near the end of discharging, the cell generates a tremendous amount of heat, in which case, cooling measurement should be enhanced and cooling should be maintained for 5 min at least after the end of charging.