A novel double-layer lithium-ion battery thermal management system based on composite PCM optimized heat dissipation and preservation in cold climates

Electrochemical energy storage technologies provide solutions to achieve carbon emission reductions. An advanced battery thermal management system (BTMS) is essential for the safe operation of batteries in such technologies. Due to the different demands of batteries in high- and low-temperature environments, the BTMS requires heat dissipation and preservation capabilities to adapt to different environments. Existing passive thermal management structures only focus on enhancing heat dissipation or preservation individually and cannot meet both requirements simultaneously. This study proposed a double-layer passive battery thermal management structure based on phase change material to resolve this contradiction. The double-layer structure could increase the latent heat of BTMS: the latent heat of the double-layer structure increased from 5.5 to 5.8 kJ per cell compared with a single-layer structure. The simulation results showed that the double-layer structure showed good temperature control ability. When the ambient temperature reached 35 °C, the battery pack temperature was maintained at approximately 49.2 °C. The double-layer structure could delay the heat loss at low temperatures, which helps the battery to work better in a cold environment.