Thermal performance enhancement with snowflake fins and liquid cooling in PCM-based battery thermal management system at high ambient temperature and high discharge rate

Abstract

The application of phase change materials (PCMs) in battery thermal management system (BTMS) is restricted by their low thermal conductivity and the challenge of heat-storage saturation after latent heat depletion, particularly in conditions with high ambient temperature and discharge rate. To enhance the performance of thermal management, this study firstly evaluates the thermal behaviors of two designs, Batteries-PCM and Batteries-PCM-Fins, under discharge rates of 3C and 5C, in conjunction with ambient temperatures of 25 °C and 40 °C. Building on this foundation, a hybrid thermal management system that incorporates snowflake fins and liquid cooling is proposed. The cooling efficiency of five different liquid cooling plate configurations (Design I-V) is compared, and the impact of coolant flow rate is explored. The results indicate that the snowflake fins in the Batteries-PCM-Fins design effectively reduce battery temperatures at a 3C discharge rate, maintaining a max temperature difference below 3 °C. However, at a 5C discharge rate and 40 °C ambient temperature, there is a noticeable increase in the peak temperature of the battery module across numerous cycles. Among the tested designs, Design IV shows the best performance. Specifically, when the coolant flow rate is 0.1 m/s, the discharge rate is 5C, and the ambient temperatures are 25 °C and 40 °C, compared to the design lacking a liquid cooling plate, the maximum temperature of the battery module decreases by 17.40 % and 21.36 % respectively, with respective decreases of 42.53 % and 55.77 % in the maximum temperature difference.