Thermal Management Performance of Lithium-Ion Battery Using Supercritical CO2 as Cooling Fluid

Thermal management system is very crucial to guarantee the safe and high-efficient operation of lithium-ion batteries, and different kinds of medium, such as air, water and phase change material, can be adopted in thermal management systems. However, these mediums are still less than satisfactory when it comes to the stressful conditions. In this study, a new medium - supercritical CO2 is proposed to be used in controlling the temperature of lithium-ion batteries. Numerical simulations are conducted to investigate the feasibility and superiority of supercritical CO2 as the thermal management medium. The effects of inlet parameters of supercritical CO2 on the cooling performance are studied, and the underlying mechanisms for the superiorities of supercritical CO2 are revealed. The results indicate that supercritical CO2 around the critical point possesses the combined benefits of phase change material and liquid medium, making it a prominent medium for battery thermal management system. The superiorities of supercritical CO2 mainly originate from the large specific heat region around the pseudocritical point, and these advantages endow supercritical CO2 excellent capabilities coping with stressful conditions, such as high discharging rates and scorching weather.