Multi-objective optimization based on liquid-air composite cooling system of cylindrical lithium-ion battery

Effective thermal management is imperative for maintaining the thermal safety and homogeneity of lithium-ion (Li-ion) batteries, especially when subjected to high temperature environments. This study proposes an innovative composite thermal management system incorporating a synergistic combination of microchannel liquid cooling and air cooling mechanisms, specifically engineered for 18,650 lithium-ion battery applications. Additionally, the heat-conducting sleeves are installed around the battery periphery to improve heat transfer efficiency. The effects of heat-conducting sleeve height (h), cooling air velocity (v), and cooling liquid inlet temperature (Tin) on heat dissipation performance of composite system were considered. The results show that both the maximum temperature (Tmax) and temperature difference (Delta Tmax) decrease as the height of the heatconducting sleeve and the cooling air velocity increase. Furthermore, the Non-dominated Sorting Genetic Algorithm (NSGA-II) is used to optimize these three parameters, and the maximum temperature (Tmax), maximum temperature difference (Delta Tmax) and additional power consumption (Pw) were used as the optimization objectives. The optimized results demonstrate significant improvements: when h = 59.82 mm, v = 4.87 m/s, and Tin = 297.38 K, the cooling system achieves optimal performance, with Tmax, Delta Tmax, and Pw reduced by 3.8 %, 10.9 %, and 4.65 %, respectively. These results verify the enhanced cooling capacity of the optimized system.