基于热电效应与相变耦合的锂离子电池热管理数值研究

Numerical analysis of thermal management of Li⁃ion battery based on thermoelectric effect coupled with phase change materials

温度对锂离子电池工作性能影响巨大,需要增设热管理系统对电池在高温工况下散热。文中建立了一种基于热电效应和相变材料耦合的电池热管理系统,采用半导体制冷片冷端直接为电池制冷,热端采用相变材料散热。为进一步强化系统散热性能,通过数值模拟的方法探究半导体制冷片及相变材料对电池散热的影响。结果表明:半导体制冷片在高工作电流下,其制冷效果突出,但存在电池内部温差过大、相变材料短时间失效等问题难以在电池放电全程维持其合适工作温度,可应用于紧急情况下为电池迅速散热。当制冷片在低工作电流下工作时,制冷片输入工作电流为0.4—0.6 A,相比电池无热管理系统下的平均温度,电池最高平均温度降低约45℃,电池在放电全程散热效果显著,且电池内部最大温差小于5℃,均匀性良好。相变材料的熔点及潜热值大小对热管理系统散热性能也起到了重要作用。

The temperature plays very important roles in the operation of Li⁃ion battery,so thermal management system is necessary to dissipate heat from the battery when temperature is high.The battery thermal management system based on thermoelectric effect coupled with phase change material was established.The cold end of the semiconductor chilling plate was used to cooling the battery directly,and the heat dissipated from its hot end was absorbed by phase change material.In order to enhance the heat transportation performance of the system,the temperature of the battery was predicted with numerical analysis method to evaluate the influence of the semiconductor chilling plate and phase change material on the heat dissipation of the battery.The results show that the cooling effects of the thermal management system is outstanding,but there are some problems such as large temperature difference inside the battery,phase change material failure in a short time,etc.When the current of the semiconductor chilling plate is 0.4⁃0.6 A,compared to the average temperature of the battery without a thermal management system,the maximum temperature of the battery is reduced by about 45℃,the heat dissipation effect of the battery is significant in the whole discharging process,and the maximum temperature difference within the battery is less than 5℃.The melting point and latent heat value of phase change materials also play important roles in the heat dissipation performance of thermal management system.