Cooling-preheating dual-functional battery thermal management system based on modular assembly phase change materials

Phase change materials (PCMs) have been widely applied in the field of battery thermal management systems (BTMSs), benefiting from their passive temperature control characteristics of heat absorption at high temperatures and heat release at low temperatures. To address the issues of low heat exchange efficiency and low energy density in PCM-integrated BTMSs, this work designs a cooling-preheating dual-functional BTMS based on modular assembly (MA) PCMs and forced air convection. The battery module constructed by sleeve-like PCM units has a much larger surface area (0.14 m 2 vs. 0.06 m 2 ) than traditional block-shaped (BS) PCM modules, thus demonstrating excellent preheating and heat dissipation performance under cold and hot forced convection, respectively. For heat-dissipation conditions, the MA module can control the maximum temperature of the battery module below 37.5, 43.2 and 47.6 °C at discharge rates of 1, 2 and 3C, respectively, with the temperature differences below 2.0 °C, which are far lower than those of the BS module. For preheating conditions, in spite of similar preheating efficiency, the temperature uniformity of the MA module is far better than that of the BS module. For example, under the preheating power of 120 W, the peak temperature difference of the MA module is 6.5 and 7.6 °C lower than that of the BS module under ambient temperatures of 0 and − 20 °C, respectively. Furthermore, since the MA module eliminates the use of distal PCMs with low utilization, the energy density of the battery module is increased by 12%.