CPCM/液冷复合电池热管理方式优化设计

Optimization Design of Thermal Management Mode of CPCM/Liquid-Cooled Composite Battery

目的为了解决锂电池组在放电倍率为2.5 C,环境温度为308.15 K下工作时,其最高温度、最大温差可能超过适宜温度的情况。方法建立基于复合相变材料(CPCM)/液冷复合的电池组散热模型,首先通过实验测得锂电池单体相关性能参数,然后利用数值模拟方法讨论CPCM厚度对电池组散热性能的影响。分析得出当CPCM厚度在一定范围内变化时,单一的相变材料冷却方式不能将电池组最高温度控制在适宜的温度范围内,因此提出CPCM/液冷复合散热方式,以复合相变材料厚度、液冷通道间距、液体流速为设计变量,电池组最高温度和最大温差为优化目标进行多目标优化设计。结果结果表明,优化后的电池组最高温度和最大温差分别为316.88K和0.30K,满足设计要求,但相变材料在相变过程中存在泄露的风险。结论相较于单一的相变材料冷却方式,优化后的复合冷却模型能够大幅度降低电池组的最高温度,同时将最大温差控制在安全范围内;在保证散热模型最外层包装结构具有较高导热性的同时也要加强其结构设计,防止相变材料泄露。

In order to solve the situation that the maximum temperature and maximum temperature difference of lithium battery pack may exceed the suitable temperature range when it works at 2.5 C discharge rate and 308.15 K ambient temperature. The heat dissipation model of the battery pack based on composite phase change material(CPCM)/liquid-cooled composite is established. Firstly, the related performance parameters of the lithium battery were measured by experiments. Then, the influence of CPCM thickness on the heat dissipation performance of battery pack was discussed by numerical simulation method. The analysis shows that the maximum temperature of the battery pack could not be controlled within an appropriate range by a single phase change material cooling mode when the thickness of CPCM varied within a certain range. Therefore, CPCM/liquid-cooled composite heat dissipation method was proposed,and the Multi-objective optimization design was carried out with the thickness of composite phase change material, liquid-cooled channel spacing and liquid flow rate as the design variables, and the maximum temperature and maximum temperature difference of the battery pack as the optimization objectives. The results show that, the maximum temperature and maximum temperature difference of the optimized battery pack are 316.88 K and 0.30 K respectively, which meet the design requirements, but there is a risk of leakage of the phase change material during the phase change process. Compared with the single phase change material cooling method, The optimized composite cooling model can significantly reduce the maximum temperature of the battery pack, while controlling the maximum temperature difference within a safe range. While ensuring high thermal conductivity of the outermost packaging structure of the heat dissipation model, the structural design should be strengthened to prevent the leakage of phase change materials.