Compact design of integrated battery thermal management systems enabled by bi-functional heating-cooling plates and temperature-equalizing strategy

Abstract

Pursuing high cooling-preheating performances of integrated battery thermal management system (BTMS) inevitably complicates the module structure, leading to great decreases in energy densities. To unblock this trade-off relationship, we propose a compact and lightweight integrated-BTMS by introducing bi-functional heating-cooling plates (BF-HCPs) and temperature-equalizing strategies based on differentiated inlet velocities (vI and vII) and heating powers (PI and PII). Firstly, the skillful design of BF-HCPs simplifies the structure of BTMS by reducing individual heating/cooling accessories. Subsequently, multi-objective optimization of vI, vII, PI, PII and channel width ratio (WR) realizes temperature equalization in large modules. The optimal WR locates at 0.60–0.65; differentiated vI and vII is fixed at large values of 0.25 and 0.16 m·s−1, respectively; the total PI + PII is preferably larger than 695 W with a narrow PII/PI of 0.53–0.56. Consequently, the obtained BTMSs demonstrate outstanding comprehensive performances. In cooling mode, the maximum temperature and temperature difference can be controlled below 30 and 3 °C at 4-C discharge. In preheating mode, the preheating time is lower than 500 s with a temperature difference < 3 °C. Furthermore, the obtained battery module possesses higher energy densities of 143.6 Wh·kg−1 and 332.2 Wh·L−1 than the reported battery modules with existing integrated BTMSs.