Thermal Performance Analysis of Lithium-Ion Battery Module Using Direct Liquid Cooling with Different Coolants

Abstract

Efficient thermal management is essential for ensuring the safety, performance, and longevity of lithium-ion battery systems. This study investigates the thermal behavior of a battery module under direct liquid cooling using computational fluid dynamics (CFD) model. The model was employed to evaluate the effects of coolant type, flow velocity, and inlet temperature on temperature distribution and overall cooling performance. Four working fluids (deionized water, ethylene glycol, mineral oil, and Novec 7300) were comparatively analyzed. Deionized water achieves the lowest maximum temperature due to its high thermal conductivity and specific heat capacity, while Novec 7300 shows the weakest cooling capability. Increasing coolant velocity effectively reduces peak temperature by enhancing convective heat transfer, whereas lowering inlet temperature decreases the overall temperature level with limited impact on temperature uniformity. The results further reveal a trade-off between peak temperature reduction and temperature uniformity, indicating that stronger cooling may induce larger thermal gradients. Therefore, thermal management design should balance cooling capacity and uniformity. Overall, selecting a coolant with superior thermophysical properties is more effective than solely adjusting operating parameters.