锂电池热失控爆炸超压及液氮惰化效果分析

Analysis of thermal runaway explosion overpressure and liquid nitrogen inerting effect of lithium battery

为明确液氮对280 Ah储能锂电池热失控燃爆的惰化效果,在试验分析电池热失控气体成分和爆炸极限的基础上,利用火焰加速模拟(FLACS)软件模拟计算储能集装箱内电池热失控气体爆炸超压后果,并开展标准试验和实体试验,分析液氮对电池热失控气体的惰化抑爆效果。结果表明:热失控气体爆炸超压随着自身体积的增多逐渐升高,点燃超过1.1 m^(3)热失控气体会造成较为严重的后果;单个100%充电状态的280 Ah磷酸铁锂电池,真空状态下加热可触发电池热失控,并产生134.6 L以CO_(2)、H_(2)、CO、CH_(4)和C_(2)H_(4)为主要成分的热失控气体。热失控气体为可燃气体,爆炸极限范围为8.5%~45.5%;N_(2)能够有效惰化热失控气体,并显著减小热失控气体爆炸极限范围,极限N_(2)体积分数为84.7%;向35 m^(3)储能集装箱内喷射69 kg液氮惰化电池热失控气体,当箱内N_(2)体积分数高于极限N_(2)体积分数时能够有效惰化电池热失控气体,有效保护时间为2200 s。

In order to clarify inerting effect of liquid nitrogen on the thermal runaway explosion of a 280Ah energy storage lithium battery,based on experiment analysis of composition and explosion limit of battery thermal runaway gas,FLACS was used to simulate explosion overpressure of battery thermal runaway gas in a storage container.Standard experiments and real experiments were carried out to analyze inerting effect of liquid nitrogen on battery thermal runaway gas.Results show that thermal runaway gas explosion overpressure increases gradually with an increase of its volume.Ignition of more than 1.1 m^(3) of thermal runaway gas can cause serious consequences.A single 280 Ah lithium iron phosphate battery in 100%charged state,heating in a vacuum state,heating in a vacuum state can trigger thermal runaway of the battery and produce 134.6 L of thermal runaway gas with CO_(2),H_(2),CO,CH_(4)and C_(2)H_(4)as the main components.Thermal runaway gas is a flammable gas,and explosion limit range is between 8.5%and 45.5%.N_(2)can effectively inert thermal runaway gas and significantly reduce the explosion limit range of thermal runaway gas.Limiting N_(2)volume fraction is 84.7%.Spray 69 kg liquid nitrogen into a 35 m^(3) energy storage container to inert battery thermal runaway gas.When volume fraction of N2 is higher than limiting nitrogen volume fraction,battery thermal runaway gas can be effectively inerted,and effective protection time is 2200 s.