锂电池相变材料/风冷综合热管理系统温升特性

锂电池在高倍率充放电过程中会产生大量热量,此热量不及时散出会导致电池超温进而影响电池的使用寿命,甚至导致安全事故。本文设计了一种新型相变材料/风冷综合热管理系统(TMS),并对综合热管理方式下的电池温升特性进行了实验和理论研究。基于集总参数法,结合电池生热及散热机理,建立了电池发热功率计算模型以及相变材料/风冷综合TMS电池温度场数学模型,计算了电池单体发热功率,分析了环境温度、电池充放电循环初始温度、相变温度、对流热阻以及电池和相变材料之间的导热热阻对电池综合TMS性能的影响。结果表明:综合TMS的冷却性能优于纯风冷热管理系统;电池充放电过程为非稳态传热过程,因此较高的初始温度带来超温风险;电池温度场数学模型能准确反映电池升温行为;较高的环境温度下,电池最大温升幅度降低,但可能导致电池最高温度超过安全温度;相变材料的相变温度越低,电池最大温升越低;减小导热热阻及对流热阻能显著提高TMS性能。

Temperature rise characteristic of lithium battery integrated thermal management system combining phase change materials with air cooling

A large amount of heat inside the lithium battery must be dissipated to ensure the safety of the battery by using high efficiency thermal management system (TMS) at high charging/discharging rates.A newly designed TMS integrating phase change material with air cooling was designed and its temperature rise characteristic was investigated theoretically and experimentally.Based on the lumped parameter method and the heat transfer mechanism,the mathematical models of temperature rise and heat generation power were developed for the battery.The battery heat generation power was calculated.The key parameters of ambient temperature,initial temperature,phase change temperature,convective resistance and conductive resistance between the battery and the phase change material affecting the performance of the integrated TMS were analyzed.The results indicate that the performance of the integrated TMS is superior to the pure air cooling system.In the non-steady process of temperature rise during charging and discharging,the higher initial temperature easily causes the battery to exceed the safe temperature.The mathematical model of the battery temperature field can accurately describe the battery temperature rise characteristic.At high ambient temperature,the maximum temperature rise of battery declined,but it may cause the maximum temperature to exceed the safe temperature.The higher phase change temperature is,the lower battery maximum temperature rise is.Reducing conductive resistance or convective resistance can significantly improve the performance of the TMS.