Design of battery thermal management system based on phase change material and heat pipe

•The cooling performance of the BTMS with heat pipe and PCM is investigated.•Effect of PCM on the performance of BTMS with HP and PCM is studied.•Influence of different parameters on the performance of BTMS is studied.•A strategy is proposed to optimize the thickness distribution of PCM in the BTMS.•ΔTm in optimized BTMS is reduced by 30% without increasing system investment. In this paper, the performance of battery thermal management system (BTMS) with phase change material (PCM) and heat pipe (HP) is studied. The performance of the BTMS is compared to that of the one with solely HP, find that PCM can effectively reduce the temperature difference in battery pack. Then, the influences of the environmental parameters, the parameters of the HP and PCM on system performance are investigated using numerical method. The results show that increasing environmental convective heat transfer coefficient (h), latent heat and thickness of PCM, or decreasing ambient temperature can reduce the maximum temperature in battery pack while increasing the temperature difference. Increasing the equivalent thermal conductivity of the started HP (kHP-S) and reducing the start temperature can improve the heat dissipation of battery pack. When the melting temperature of PCM is lower than the start temperature of HP, the temperature difference of battery pack is large. Furthermore, to improve the temperature uniformity in battery pack, an effective strategy for optimizing the thickness distribution of PCM is proposed without increasing the system volume and investment. The optimized results under different conditions show that adjusting the thickness distribution of PCM can effectively improve the system performance when kHP-S is small and h is moderate. The maximum temperature difference in battery pack is reduced by 30% after the optimization.