低压下不同包装航空运输锂电池热失控特性研究

Study on thermal runaway characteristics of lithium battery with different packaging in air transportation under low pressure environment

为探究民用航空运输锂电池在起飞、进近和巡航阶段等低压环境下的热失控特性,分别在起飞、进近(90 kPa)和巡航阶段(20 kPa)的环境压力下,采用外部热源触发锂电池热失控。通过分析热失控过程中的热失控现象、电池表面中心温度、热释放速率和烟气变化,探究21700圆柱和软包锂电池在低压环境下的热失控特性,并对两种包装形式锂电池的热失控特性进行对比。结果表明:环境压力降低会导致21700圆柱和软包锂电池的热失控强度减弱;当环境压力从90 kPa降至20 kPa时,21700圆柱和软包锂电池的表面中心温度分别从603.2℃和686.4℃降低为420.6℃和627.3℃,同时热失控触发温度分别从218.5℃和134.5℃上升至230.8℃和158.4℃。在90 kPa和20 kPa环境压力下,单位容量的软包锂电池热失控产生的CO_(2)高于圆柱锂电池,但产生的CO少于圆柱锂电池。

In order to investigate the thermal runaway characteristics of lithium battery in civil aviation transportation under low pressure environment such as takeoff,approach and cruise,this paper uses external heat source to trigger thermal runaway of lithium battery under the environmental pressure of takeoff,approach(90 kPa)and cruise(20 kPa)respectively.The thermal runaway characteristics of 21700 cylindrical and soft packed lithium batteries are explored and compared by analyzing the thermal runaway phenomenon,the change of the battery surface center temperature,the heat release rate and the smoke during the thermal runaway process.The experimental results show that the thermal runaway strength of 21700 cylindrical and soft packed lithium batteries will be reduced when the ambient pressure decreases;When the ambient pressure drops from 90 kPa to 20 kPa,the surface center temperature of 21700 cylindrical and soft packed lithium batteries decreases from 603.2℃and 686.4℃to 420.6℃and 627.3℃respectively,and the thermal runaway trigger temperature increases from 218.5℃and 134.5℃to 230.8℃and 158.4℃respectively.Under the environment of 90 kPa and 20 kPa,the CO_(2)content produced by the soft packed lithium battery with unit capacity is higher than that of the cylindrical lithium battery,but the CO content produced is less than that of the cylindrical lithium battery.