相变材料和液冷结合的锂离子电池热管理性能优化

Thermal management performance optimization of lithium-ion batteries combined with phase change materials and liquid cooling

相变材料因其良好的控温能力在电池热管理中得到了广泛的研究,但在高温环境和高放电倍率下,单纯依靠相变材料很难满足热管理的要求。设计了相变材料和冷却板混合的电池热管理方式并对其进行数值模拟,与采用纯相变冷却进行了对比。分析了电池间距、冷却液入口速度对电池最高温度以及相变材料液化率的影响,并对充放电循环过程进行了探究。结果表明,在高温和高放电工况下,液冷的引入解决了因相变材料完全液化导致的电池温度恶化和中间电池热量累积的问题。相比于纯相变冷却,当冷却液速度为0.5 m/s时,混合冷却可将电池的间距减小至3 mm,继续增大冷却液的速度对热管理性能提升较小。同时,液冷板的加入可以减少首次充放电循环对后续循环过程的影响,增加电池的使用寿命。

Phase change materials have been widely studied in battery thermal management due to their good temperature control capabilities,but in high temperature environments and high discharge rates,it is difficult to rely solely on phase change materials to meet the requirements of thermal management.Therefore,a battery thermal management method with a mixture of phase change materials and cooling plates was designed and numerically simulated and compared with pure phase change cooling.The effects of distance and coolant inlet velocity on the maximum temperature of the battery and liquid fraction of phase change materials were investigated,and the charge-discharge cycle process was also investigated.The results show that the addition of liquid cooling solves the problems of battery temperature deterioration and intermediate battery heat accumulation caused by complete liquefaction of phase change materials under high temperature and high discharge conditions.Compared with pure phase-change cooling,the hybrid cooling can reduce the cell spacing to 3 mm when the coolant velocity is 0.5 m/s and the thermal management performance can be improved less by continuing to increase the cooling liquid velocity.At the same time,the addition of the liquid cooling plate can reduce the influence of the first charge-discharge cycle on the subsequent cycle process and increase the lifetime of the batteries.