Abstract: Aiming at the problem of heat dissipation in lithium battery pack, a hybrid liquid cooling system combined with the bifurcation liquid cooling channel with the composite phase change material was proposed and its heat dissipation performance was studied numerically.Firstly, the heat production of the battery was obtained through the charge and discharge experiment of the single battery.Secondly, a three-dimensional battery pack model was established.Taking the number of cooling channels at all levels and the thickness of composite phase change materials as design variables, the optimal Latin square method was used to construct 44 test sample points.Thirdly, the approximate model was established based on the response surface method, and the multi-objective particle swarm optimization algorithm was used for optimization design.Finally, the effect of coolant mass flow rate was also discussed.The results show that when the number of stages in the bifurcated liquid cooling channel and the thickness of composite phase change materials are 5, 5, 7 and 5.659 9 mm respectively, better cooling performance can be obtained, and the maximum temperature, maximum temperature difference and pressure drop are reduced by 3.4%, 35.36% and 46.50%, respectively.

Key words: vehicle engineering；battery thermal management； liquid cooling；phase change cooling；composite phase change material；multi-objective particle swarm optimization algorithm

摘要： 针对锂电池组散热问题，提出了一种将分岔液冷通道与复合相变材料相结合的复合液冷系统，并对其散热性能进行了数值研究。首先，通过单体电池充放电实验，得到电池的产热量；其次，建立三维电池组模型，以冷却通道各级数量和复合相变材料的厚度为设计变量，采用最优拉丁方方法构建44个试验样本点；然后，基于响应面法建立近似模型，并采用了多目标粒子群算法，进行优化设计；最后，讨论冷却液质量流量的影响。结果表明：当分岔液冷通道各级数量为5、5、7，复合相变材料厚度为5.659 9 mm时，可获得更好的冷却性能, 其最高温度、最大温差和压降分别减少了3.40%、35.36% 和 46.50%。

关键词: 车辆工程；电池热管理；液体冷却；相变冷却；复合相变材料；多目标粒子群优化算法