复合相变材料/空冷复合式锂离子电池模块散热性能

锂离子电池放电过程中产生的热量无法及时消散会导致电池性能下降，设计合理的电池组散热结构是提升电池性能的关键一环。提出一种复合相变材料（CPCM）与空冷结合的电池组散热结构。利用伪二维电化学模型与三维散热模型相结合，将电池产热过程、电池与外界传热过程进行解析，探究了相变材料（PCM）厚度、CPCM中膨胀石墨（EG）的含量、空冷孔道数量及空冷气体流通方向对电池组散热性能的影响。结果表明，CPCM/空冷复合式散热结构的散热性能明显优于只用CPCM的电池组，且当PCM厚度等于电池半径、EG质量分数为20%时，电池组散热性能最佳。此外，双向通风管道设计可以更有效地降低电池温度。所得结论可为锂离子电池组的散热设计提供理论指导。

Heat dissipation performance of the module combined CPCM with air cooling for lithium-ion batteries

The heat generated during the discharge of lithium-ion batteries cannot be dissipated in time, which will lead to a decrease in battery performance. Designing a reasonable heat dissipation structure of the battery pack is a key part of improving battery performance. In this paper, a cooling structure of battery pack based on the combination of composite phase change materials (CPCM) and air cooling is proposed. By combining the pseudo two-dimensional electrochemical model with the three-dimensional heat dissipation model, the heat generation process of the battery and the heat transfer process between the battery and the outside were analyzed, and the effects of the thickness of phase change material (PCM), the content of expanded graphite (EG) in the CPCM, the number of air cooling channels and the flow direction of air cooling gas on the heat dissipation performance of the battery pack were investigated. The results show that the heat dissipation performance of the CPCM/air cooling composite heat dissipation structure is significantly better than that of the battery pack only using CPCM. When the PCM thickness is equal to the battery radius and the EG mass fraction is 20%, the heat dissipation performance of the battery pack is the best. In addition, the two-way ventilation duct design can reduce the battery temperature more effectively. The conclusions can provide theoretical guidance for the heat dissipation design of lithium-ion battery pack.