A novel hybrid battery thermal management system using TPMS structure and delayed cooling scheme

Phase change material (PCM) cooling plays an important role in battery thermal management systems (BTMS). However, PCM has been suffering from low thermal conductivity and inefficient latent heat recovery. Based on this, this study designs a hybrid BTMS combining triply periodic minimal surface (TPMS), PCM, and liquid cooling, and proposes a cooling scheme that determines the operating time of the coolant based on the battery temperature. The system aims to improve the utilization of PCM in two different ways: structural design and cooling scheme. Numerical analysis was used to compare the effects of different structures on the melting rate of PCM and to study the thermal performance of the battery module under various cooling schemes. The results show that the effective thermal conductivity of PCM/TPMS composites reaches 21 W/(m & sdot;K), which can effectively enhance the heat absorption rate of PCM. In particular, the I-graph-and-wrapped-package (IWP) structure combined with PCM is the most effective. Under the continuous cooling scheme, when the coolant flow rate is 0.04 m/s, the temperature of the battery at a 3C discharge rate can be controlled at 308.28 K, but the PCM utilization rate is only 0.25. After adopting the delayed cooling scheme, the performance of the BTMS cooling remains excellent, with the battery temperature at only 309.88 K and the liquid phase rate of PCM reaching 0.97. For the first time, the heat absorbed by passive cooling is comparable to that of active cooling in the BTMS heat absorption energy distribution, with a 73 % reduction in pumping energy consumption. Furthermore, under cycling conditions, the delayed cooling scheme still performs well, keeping the battery temperature below 313.15 K. In addition, it should be noted that the flow rate of the coolant should be determined by the charging rate. Additionally, the BTMS is capable of addressing the heat dissipation challenges in different ambient temperatures. This study can guide for the design of PCM in hybrid BTMS.