Performance improvement of a thermal management system for Lithium-ion power battery pack by the combination of phase change material and heat pipe

A novel hybrid battery thermal management system (BTMS) by combining phase change materials (PCM) and heat pipes (HP) is proposed for the power battery pack in this study. The HP of the hybrid BTMS locates between the batteries and directly contacts with the batteries. A comparative analysis of the thermal performance is numerically conducted between the BTMS with PCM + HP and the system with only PCM. The results demonstrate that the system with PCM + HP outperforms the system with only PCM for all studied discharge rates from 2C to 4C. The maximum temperature of the power battery pack is significantly decreased by combining PCM and HP. The maximum temperatures observed for discharge rates of 2C, 3C, and 4C decrease from 47.99 °C, 59.83 °C and 76.74 °C to 38.19 °C, 45.91 °C and 49.98 °C, respectively, which are 25.7 %, 23.3 %, and 34.9 % lower than the system with only PCM. Furthermore, the PCM + HP system demonstrates an improved temperature uniformity within 2 °C and 5 °C at a discharge rate of 3C for h = 15 and 60 W/(m2·K), respectively, in contrast to the maximum value of 9.76 °C observed in the PCM system. Thus, the proposed PCM + HP BTMS exhibits prominent advantages in controlling the maximum temperature as well as the temperature uniformity, and has considerable application potential in BTMS.