Abstract: In view of the difficulty in heat dissipation of battery pack of pure electric vehicle, based on COMSOL Multiphysics software simulation platform, the 18650 cylindrical lithium-Ion battery was taken as the research object to establish the thermal model of power battery pack, and different heat dissipation schemes were compared and studied. Taking the maximum temperature and temperature difference of the battery pack as reference, the battery working condition was simulated by changing the discharge rate, and the heat dissipation performance of the battery pack was analyzed and compared under three schemes: natural cooling with different air supply modes, forced cooling with different convection heat transfer coefficient and inlet wind speed. The results show that the serial channel structure is superior to the parallel channel structure for the natural cooling of the battery pack at low discharge rate. When the discharge rate is high, the power battery pack should adopt forced cooling for heat dissipation. The high inlet wind velocity under forced cooling can effectively improve the heat dissipation performance of the battery pack. This provides an important reference for the selection of the supply air channel structure of the power battery pack and the setting of the inlet air velocity of the heat dissipation system.

Key words: Power battery pack; Heat dissipation performance; Heat dissipation simulation; Ventilation way

摘要： 针对电动汽车动力电池组散热困难的问题，基于多物理场耦合仿真平台，以 18650 圆 柱形锂离子电池为研究对象，建立动力电池组热模型，并采用不同散热方案进行对比研究。 以电池组最高温度及温差值作为参考，通过改变放电倍率来模拟电池组工况，分析对比不同 送风方式的自然冷却、不同对流传热系数和入口风速的强制冷却这 3 种方案下电池组的散热 性能。结果表明，电池组处于低放电倍率下采用串行通道结构进行自然冷却优于采用并行通 道结构；高放电倍率工作时，对动力电池组应采取强制冷却进行散热；强制冷却下高流速的 入口风速能够有效地提高电池组的散热性能。为动力电池组的送风通道结构选择及散热系统 入口风速设置提供重要参考。

关键词: 动力电池组；散热性能；散热仿真；通风方式