低温条件下基于相变材料的锂离子电池保温特性分析

Analysis of thermal insulation characteristics of lithium-ion batteries based on phase change materials under low temperature

低温环境会较大地限制锂离子电池的容量及输出功率。为维持低温条件下电池在适宜的温度范围内工作,本文利用GPU加速的基于焓法的多松弛时间格子玻尔兹曼方法(MRT-LBM)模拟研究了-20℃、-10℃和0℃的环境温度下,五次充-放电循环过程中不同相变温度的相变材料(PCM)对电池的保温效果。结果表明,当环境温度为0℃、相变温度为26~30℃范围内的PCM能使电池在第2次循环后处于20.0~45.0℃的最佳温度范围内工作,且令电池温差小于4.6℃。当环境温度为-10℃,使用相变温度为22~28℃的PCM使电池在30min后达到0℃,且整个过程电池温差小于4.3℃。此外,经历3次充放电循环后,电池平均温度在20.0~28.9℃区间内,相同相变温度下最高温度的波动幅度小于1.0℃。当环境温度为-20℃时,仅依靠PCM保温作用,电池组在运行140min后工作温度才能达到0℃,故需要结合其他预热系统使电池在短时间内达到适宜工作温度。

The low temperature condition can greatly limit the capacity and output power of lithium-ion batteries.In order to maintain the batteries in the suitable temperature range under low-temperature conditions,the GPU-accelerated multi-relaxation time lattice Boltzmann method(MRT-LBM)was adopted to investigate the effect of phase change temperatures of PCM on the battery during five charge-discharge cycles at ambient temperatures of-20℃,-10℃and 0℃.The results showed that when the ambient temperature was 0℃,the PCM with phase change temperature in the range of 26—30℃could enable the battery to operate in the optimal temperature range of 20—45℃after the second cycle,and the temperature difference of the battery was less than 4.6℃.When the ambient temperature was-10℃,the battery reached 0℃after 30 minutes with a PCM in the phase change temperature range of 22—28℃,and the temperature difference between the batteries was less than 4.3℃throughout the process.In addition,after three charge-discharge cycles,the average battery temperature was in the range of 20.0—28.9℃,and the fluctuation of the highest temperature under the same phase change temperature was less than 1.0℃.When the ambient temperature was-20℃,the battery pack could reach 0℃after 140 minutes only by PCM insulation,and thus it was necessary to combine with other preheating systems to make the battery reach the appropriate operating temperature within a short period of time.