Abstract: Aiming at the problems of insufficient heat dissipation and high system energy consumption of lithium-ion battery packs, the effects of different semi-circular arc liquid cooling plate structures on the heat dissipation performance of battery packs and the pressure drop in the fluid domain were analyzed by Fluent software. Based on the results of three key indicators of the battery pack, that is, the maximum temperature, the maximum temperature difference and pressure drop, 8 sets of cooling structures were designed, and the structure 2 was selected to further investigate the effects of coolant inlet flow rate, inlet temperature, and liquid cooling plate height on the heat dissipation efficiency of the battery pack. The research results show that the bidirectional flow structure is more beneficial for improving the temperature uniformity of the battery pack compared to the traditional single flow structure. Adjusting the inlet and outlet positions of the coolant will change the flow distribution of the coolant, thereby affecting the heat dissipation performance of the battery pack. Increasing the coolant flow rate can reduce the maximum temperature and temperature difference of the battery pack, but when the flow rate exceeds 0.3 m/s, the improvement in heat dissipation effect will become limited and the system energy consumption will increase. Lowering the coolant temperature can effectively reduce the maximum temperature of the battery pack, but it will increase the temperature difference of the battery pack. Increasing the liquid cooling plate height helps to enhance the heat dissipation effect of the battery pack and improve temperature uniformity. When the coolant flow rate is 0.3 m/s, the coolant inlet temperature is not lower than 25 ℃, and the height of the liquid cooling plate is not less than 55mm, the maximum temperature of the battery pack after cooling with structure 2 is 30.61 ℃, and the maximum temperature difference can be controlled within 5 ℃, which has a better temperature uniformity.

Key words: vehicle engineering; lithium-ion battery; cooling structure; thermal uniformity; Fluent simulation

摘要： 针对锂离子电池组存在散热不足和系统能耗高问题，利用Fluent软件分析了不同半圆弧形液冷板结构对电池组散热性能及流体域压降的影响。基于电池组的最高温度、最大温差和压降这3个关键指标，设计了8组冷却结构，并选取结构2进一步对冷却液的入口流速、 入口温度以及液冷板高度对电池组散热效果的影响进行了分析。研究结果表明：与传统单一流向结构相比，双向流结构更有利于改善电池组的温度均衡性；调整进出口位置会改变冷却液的流动分布，进而影响电池组的散热性能；增加冷却液流速可降低电池组的最高温度和温差，但当流速超过0.3 m/s时，散热效果的提升将变得有限，且会增加系统能耗；降低冷却液温度能有效降低电池组的最高温度，但会增大电池组温度差异；增加液冷板高度有助于增强电池组的散热效果并改善温度均匀性。当冷却液流速为0.3 m/s，冷却液入口温度不低于25 ℃，液冷板高度不小于55 mm时，采用结构2冷却后的电池组最高温度为30.61 ℃，同时最大温差可控制在5 ℃以内，具有更好的温度均衡性。

关键词: 车辆工程； 锂离子电池； 冷却结构； 热均衡性； Fluent仿真