Investigation on electro-thermal characteristics and heat transfer of immersion cooling for lithium-ion battery module at high-ambient temperature

Immersion cooling technology efficiently dissipates heat from battery modules, particularly during fast charging and discharging. However, research on the coupled effect of electrical and thermal performances in forced flow immersion cooling (FFIC) battery modules at high ambient temperatures is still insufficient. In this study, an immersion-cooled battery module with varying inlet and outlet configurations is experimentally analyzed to investigate its thermal and electrical characteristics. The results indicate that at an ambient temperature of 35 °C, the battery module with 3 inlets & 3 outlets has the lowest temperature of 40.6 °C with a temperature difference of 4.7 °C during 3C discharge. Additionally, When the discharge depth for 2C and 3C rates falls below 85 %, the voltage deviation (δ_U,t) stabilizes at 2 % and 2.5 %, respectively. At the end of 2C and 3C discharge, the maximum δ_U,t are 7.7 % and 7.5 %, respectively. According to the Pearson correlation coefficient analysis reveals a strong negative correlation between δ_U,t and the average temperature of the battery module, with correlation coefficients of −0.82. Furthermore, theoretical analysis of heat transfer characteristics during battery discharge is conducted to better understand the impact of different inlet and outlet configurations on FFIC.