基于液冷的锂离子动力电池散热结构优化设计

Optimal Design of Heat Dissipation Structure of Lithium-ion Power Batteries Based on Liquid Cooling

针对锂离子电池单体成组后温度场的非均匀性导致的热不一致性问题,以及高温下电池单体间的热交互引发的热安全性问题,采用仿真与试验相结合的方式,基于锂离子电池生-传热机理,设计了电池单体单独成组、电池单体之间夹隔泡沫棉、电池模组底部布置液冷板3种递进式散热方案,并对液冷板进行了优化设计.采用有限元软件STAR-CCM+,仿真分析了3种方案下电池模组在不同放电倍率时的温度分布.结果表明:增加泡沫棉可减少电池间的热交互,进而提高电池单体间的热均衡性.在结合泡沫棉、导热板以及优化后(采用液冷管道串-并联组合方式)的液冷系统散热条件下,电池模组以2C倍率放电时最高温度为35.08℃,最大温差仅为4.85℃.研究结果可为电池热管理散热系统结构设计提供一定的理论基础.

Aiming at solving the thermal inconsistency problem caused by non-uniformity of temperature field after lithium-ion battery cells are grouped,and the thermal safety problem caused by the thermal interaction between the battery cells at high temperature.The combined method with simulation and test is adopted.Three progressive heat dissipation schemes are designed based on the heat generation-transfer mechanism of lithium-ion batteries.including individual battery cells in groups,foam cotton between the battery cells,and liquid cooling plate arranged at the bottom of the battery module respectively.Also the liquid cooling plate is optimized.The finite element software STAR-CCM+is used to simulate the temperature distribution of the battery modules at different discharge rates for the three schemes.The results show that the increase of foam cotton can reduce the thermal interaction between the batteries,thereby improving the thermal uniformity between the battery cells.Under the heat dissipation condition of the combination with foam cotton,heat conducting plate and optimized(using liquid cooled pipeline series parallel combination)liquid cooling system,the maximum temperature of the battery module is 35.08℃at 2C discharge rate,and the maximum temperature difference is only 4.85℃.The research results can provide a theoretical basis for the structure design of cooling system for battery thermal management.