Lightweight lithium-ion battery hybrid cooling system and intermittent cycle operation strategy design under demanding conditions

The hybrid battery thermal management system (BTMS), suitable for extreme fast discharging operations and extended operation cycles of a lithium-ion battery pack with multiple parallel groups in high temperature environment, is constructed and optimized by combining liquid cooling and phase change materials. Compared to water cooling, the temperature and temperature difference of batteries with hybrid cooling can be decreased by up to 4.86 °C and 6.94 °C, respectively. The distance between neighboring batteries is discussed to simplify the arrangement of the hybrid BTMS, reducing mass and volume by 4.56 % and 7.75 %, respectively. Under 40 °C environment and 5C discharge conditions, the temperature difference and maximum temperature of the optimized lightweight system have been regulated to within 3.06 °C and 46.56 °C, respectively. Then, the heat accumulation during continuous operation is effectively suppressed by adding efficient laying-aside cooling during the cyclic charging and discharging process, decreasing the temperature and temperature difference by up to 4.88 °C and 3.39 °C, respectively. In summary, the lightweight hybrid BTMS reduces the complexity of traditional thermal management system while ensuring cooling performance, and the designed effective intermittent cycle operation strategy introduces a new perspective for efficient BTMS.