扁平热管和液冷复合锂电池热管理性能分析

Thermal management performance analysis of lithium battery with flat heat pipe and liquid cooling

汽车动力电池在充放电中会产生大量的热,这些热量如果不断积累会引发电池热失控。热管传热性能高,没有额外功耗。为了把锂电池的工作温度维持在最佳范围内,设计扁平热管和液冷结合的TMS(热管理系统)对电池进行散热。实验通过控制变量法研究2、3C放电速率和25、35℃的环境温度对TMS散热性能的影响,同时观察加快冷却液流速对TMS传热性能的影响。结果表明:基于扁平热管和液冷的TMS能将电池表面最高温度t_(max)控制在37℃内,相比自然对流降低了23.4℃,温差Δt均低于5℃。t_(max)和Δt均随着放电倍率的变大或环境温度的升高而变大,并且该TMS有最低超过81.74%的传热能力。表明扁平热管和液冷复合的TMS在高温和大电流下是可行且有效的。

Vehicle power batteries generate a lot of heat during charging and discharging.If the heat continues to accumulate,it will cause thermal runaway of the battery.The heat pipe has high heat transfer performance and no extra power consumption.In order to maintain the operating temperature of the lithium battery within an optimal range,a TMS(thermal management system)combining flat heat pipes and liquid cooling was designed to dissipate heat from the battery.The control variable method was used to study the influence of 2,3C discharge rate and 25,35℃ambient temperature on the heat dissipation performance of TMS.At the same time,the influence of accelerating the flow rate of coolant on the heat transfer performance of TMS was observed.The results show that the TMS based on flat heat pipes and liquid cooling can control the maximum surface temperature of the battery within 37℃,which is 23.4℃lower than that of natural convection,and the temperature difference is lower than 5℃.Both t_(max)andΔt increase with the increase of the discharge rate or ambient temperature,and the TMS has a minimum heat transfer capacity of more than 81.74%.It shows that the TMS combined with flat heat pipe and liquid cooling is feasible and effective at high temperature and high current.