Investigation on thermal management performance of PCM-fin structure for Li-ion battery module in high-temperature environment

•Thermal management system (TMS) based on PCM-fin structure is proposed.•The electro-thermal model considers thermal contact resistance during heat transfer.•PCM-fin structure achieves superior thermal control compared with pure PCM.•Optimization design is discussed on the cooling performance of PCM-fin structure.•The suitable thermal performance is exhibited in continuous charge-discharge cycles. The safety, performance and durability of the Li-ion battery module are limited by the operating temperature especially in the hot temperature regions, hence the thermal management system is essential for battery module. In this paper a novel phase change material (PCM) and fin structure was proposed for the thermal management system of LiFePO4 battery module to reduce the maximum temperature and improve the temperature uniformity in high-temperature environment (40 °C). Carefully designed experiments were performed for model validation. The effects of PCM species, fin thickness, fin spacing and PCM thickness on the cooling performance of battery module were investigated numerically. The results showed that PCM-fin structure thermal management system with optimized design exhibited good thermal performance, keeping the maximum temperature of the battery surface under 51 °C at relatively high discharge rate of 3C. Moreover, by investigating the thermal behavior of PCM during discharge process and cycle test, it has been found that PCM-fin structure has the advantage of improving natural convection and heat conduction within the PCM structure, and as a result enhances heat dissipation efficiency and reduces failure risk in passive thermal management systems using PCMs.