Comparative Study on Simulation and Experiment of Immersion and Traditional Indirect Cooling Battery Pack

In this paper, based on an indirect cooling battery pack from a hybrid car, an immersion cooling battery pack is designed. The cooling and heating characteristics of the two battery packs are calculated and analyzed by simulation. The influence of different flow rate and cell gap on the cooling performance for immersion battery pack are studied. The thermal runaway tests of immersion and non- immersion modules were carried out. The founding shows that for cooling condition, the average temperature of the indirect battery pack is 57.9℃, and the immersion battery pack is only 27.7℃.For heating condition, the indirect one needs 2630s to reach the target temperature, and immersion one only needs 950s. The coolant in immersion battery pack is contact with cell directly, which has high heat conduction efficiency, taking away the heat in time and improving safety during fast charging. There is only smoke when immersion battery module happens thermal runaway, which meets Chinese regulations GB38031-2020. However, the module without immersion cooling ejects amounts of sparks and explode. The coolant can take away the heat form battery thermal runaway directly, cut down the battery temperature, reduce the risk of thermal diffusion, and improve the safety of the battery pack.