Coupled experimental and numerical investigations of an all-climate battery thermal management system with thermal runaway barrier

Current battery thermal management systems (BTMSs) aim to dissipate the heat from battery pack in high temperatures. However, such a BTMS cannot guarantee the safe operation in other extreme conditions, such as low temperature and thermal runaway. In this study, a phase change material (PCM) based all-climate BTMS is proposed to integrate thermal management and thermal runaway mitigation within a single architecture, enabling coordinated preheating, thermal insulation, heat dissipation, and suppression of thermal runaway propagation. The results indicate that the composite PCM module extends heat-preservation time from 2550 s to 3680 s when ambient temperature dropped from 25 to 0 °C. Additionally, in 25 °C and 40 °C environments, the maximum temperatures of battery module were controlled to 43.4 °C and 56.1 °C at 2C discharge, with temperature differences of 1.7 °C and 4.2 °C, respectively. In a low temperature of −20 °C, the temperature of battery module can be heated to above 20 °C with a temperature difference of 4.8 °C. Under thermal runaway, the CPCM reduces temperature rise rates and delays neighbouring-cell runaway, as well as creates adaptive thermal buffers via dynamic phase-change along dominant heat paths. Furthermore, the simulation results show that elongated configurations can weaken thermal coupling and improved protection.