18650三元锂电池组热失控蔓延规律研究

Study on thermal runaway propagation of 18650 ternary lithium battery pack

为探究电池数量、荷电状态和电池间距对18650三元锂电池组热失控蔓延的影响,设计并搭建了电池过充引发失控过程特征参数测量的实验平台。结果表明:在本文实验条件下,单粒主发电池初爆到火焰熄灭过程约13 s,且不能引发其他电池热失控;但2粒主发电池失控可引发60%SOC以上或电池间距2mm的单粒被发电池热失控,而40%SOC或间距增至3 mm以上的单粒被发电池未失控。由此可见,足够电量的被发电池须在主发电池失控过程中获取足够热量和热流强度才会引发失控。由此可推出,若电池箱内空气中含足量有效抑爆剂,能够避免明火燃烧;若增加主发与被发电池之间热阻,同样能够避免电池组的热失控蔓延。

In order to explore the law of influence of battery number,state of charge and battery spacing on thermal runaway spread of 18650 ternary lithium battery pack,the experiment platform of measuring characteristic parameters of battery overcharge initiation and out-of-control process was designed and established.The results show that single master battery shall experience about 13 s from incipient detonation to flame extinction on condition of the current experiment and will not initiate thermal runaway to the other batteries.However,runaway oftwo master batteries can initiate thermal runaway of single receiving battery with above 60%SOC or 2 mm battery spacing,but not for single receiving battery with 40%SOC or above 3 mm battery spacing.Accordingly,thermal runaway will happen to receiving battery with sufficient electric quantity on condition of receiving sufficient heat and heat flow intensity during runaway of master battery.It can be inferred that if the air in the battery box contains sufficient amount of effective explosive inhibitor,it can avoid the burning of open flame,and thermal runaway spread of battery pack can also be avoided if thermal resistance between the master and receiving batteries increases.