Abstract: Aiming at the problems of battery life reduction and thermal safety caused by the high temperature of power battery, a square lithium-ion battery was taken as the research object. Based on the model verification of battery cell, two liquid-cooling structures of battery module, i.e. S-type and loop-type were designed. And the thermal pads were sandwiched between cells in the battery module to form liquid cooling-thermal pad combined cooling. The temperature rise characteristics of the battery module based on the combined cooling were simulated. And the effects of liquid temperature, velocity and pressure on the heat dissipation performance of the battery module at 2C rate discharge were analyzed. The results show that, at the same discharge rate, the liquid temperature difference between the inlet and the outlet with the loop-type can be increased by 23.5% compared with the S-type, and the change of the flow rate in the channel does not exceed 0.1m/s. Due to the less turning and minor pressure loss along the way in the loop-type channel, the maximum liquid pressure difference between the inlet and the outlet can be reduced by 3468Pa. Under the influence of the above three factors, the maximum temperature difference of the battery module with the loop-type can be reduced by 13.2% compared with the S-type liquid cooling.

Key words: vehicle engineering; lithium-ion battery; thermal management; liquid cooling; optimization design; performance analysis

摘要： 针对动力电池高温下导致的寿命降低及热安全等问题，以某方形锂电池为研究对象，在电池单体模型验证的基础上，设计了S型和回型两种电池模组液冷散热结构，同时在模组内单体之间夹隔导热垫片，形成液冷-导热垫复合散热。模拟了基于复合散热的电池模组温升特性，对比分析在2 C倍率放电时液体温度、速度和压强对电池模组散热性能的影响。结果表明：在相同放电倍率下，相比于S型，回型液冷通道内进出口液体温差可增加23.5%，通道内流速变化不超过0.1 m/s。由于回型通道转弯少、沿程压力损失小，进出口液体最大压差可减少3 468 Pa；3种影响因素作用下，回型相较于S型液冷散热，可使电池模组最大温差降低13.2%。

关键词: 车辆工程；锂离子电池；热管理；液冷；优化设计；性能分析