纯电动汽车锂电池组液冷散热系统的设计与仿真

Design and Simulation of Liquid Cooling System of Li-Ion Battery Pack For A BEV

基于对某纯电动汽车锂电池组参数选型而确定1P105S电池单元布局形式,设计了宽式和窄式两种液冷散热流道,并于1.5C充放电倍率时分别在25℃、45℃环境温度下对该电池组进行了温度场仿真以及在0.5m/s和1m/s入口流速下对流道流体进行了速度场仿真,结果表明:仿真与试验数据吻合良好;在相同温度、入口流速下,窄式流道液冷散热系统有更好的散热效果;窄式流道内部流体温度均匀性更好,可更好地降低电池组内部温差;窄式流道内部流体最高流速更高,冷却液流动性更剧烈,可带来更高的换热效率;当环境温度达45℃时,电池组温差超过5℃,可能会降低锂电池组性能、缩短循环使用寿命,需进一步改进液冷散热系统。

Based on the parameter selection of a BEV Li-ion battery pack,the layout of 1P105S battery cell was determined,then both a wide and a narrow liquid cooling flow channel were designed.At a charge&discharge rate of 1.5C,the temperature field simulation of battery pack was carried out at an ambient temperature of 25℃and 45℃respectively,subsequently,the velocity field simulation of fluid in flow channels was carried out at an inlet flow velocity of 0.5m/s and 1m/s respectively.The results show that the simulated and experimental data are in good agreement;at the same temperature and inlet flow rate,the liquid cooling system with the narrow channel has better heat dissipation effect;fluid in the narrow flow channel has better uniformity of temperature,which can better reduce the temperature difference inside the battery pack;the maximum flow velocity of the fluid in the narrow channel is higher,and the coolant flow is more intense,which can bring higher heat transfer efficiency;when the ambient temperature reaches 45℃,the temperature difference of battery pack exceeds 5℃,which may reduce the Li-ion battery pack performance and shorten its cycle life,then need further improvement of the liquid cooling system.