基于相变与液冷耦合的电池热管理系统研究

电池组在高环境温度下以高倍率放电时,电池组温度过高、温差大,极易引发安全问题。笔者针对这一问题设计了一种新的耦合式电池热管理系统。以采用纯石蜡冷却模型作为初始模型,首先探讨不同膨胀石墨质量分数的复合相变材料对于电池组热性能的影响,得出:在30℃的环境温度下,电池组以4C倍率放电时,采用EG质量分数为12%的复合相变材料对电池组进行冷却最优。在最优复合相变材料的基础上引入液冷系统,构建克里格近似模型,采用NSGA-Ⅱ遗传算法对耦合系统寻优,得出的预测结果精度较高误差最大仅为0.21%。利用算法寻优得出的最优解与初始模型相比,电池组最高温度下降5.29℃降幅为11.46%,最大温差下降0.12℃降幅为54.09%。结果表明:相变材料与液体冷却耦合热管理系统对电池组控温效果显著。

Research on Battery Thermal Management System Based on Phase Change and Liquid Cooling Coupling

When the battery pack is discharged at a high ambient temperature at a high rate,the excessive temperature of the battery pack may easily cause safety problems.In order to solve this problem,a new battery thermal management system is designed in this paper.The pure paraffin cooling model is used as the initial model.It is concluded that the composite phase change material with 12%EG mass fraction is the best way to cool the battery pack at 4C rate discharge at 30℃ambient temperature.Based on the optimal composite phase change material,liquid cooling system is introduced to construct Kriging approximation model.NSGA-Ⅱgenetic algorithm is used to optimize the optimization.It shows that the maximum error of high accuracy of prediction results is only 0.21%.Compared with the initial model,the optimal solution obtained by algorithm optimization reduces the maximum temperature of the battery pack by 5.29℃and 11.46%,and the maximum temperature difference drops by 0.12℃and 54.09%.The results show that the thermal management system coupled with phase change material and liquid cooling has a significant effect on the temperature control of the battery pack.