高高原环境下锂离子电池热失控烟气特性

为探究高高原机场低压低氧环境对锂离子电池热失控行为中喷射火焰温度、热释放速率及烟气组分等参数的影响,构建锂离子电池低压试验平台,以4节单体18650型锂离子电池构成电池组,分别模拟高高原机场(50 kPa)、平原机场环境(90 kPa)下锂离子电池热失控试验。结果表明:在50 kPa工况下,池体破损程度、热释放速率及喷射火焰温度均有所下降,喷射火焰峰值温度降低约241.3℃。50 kPa工况下产生的热解烟气中CxHy、CO等易燃气体浓度更高,最高体积分数分别可达3134.50×10^-6和0.860%,并且随热释放速率的增加热增加;在90 kPa工况下呈现相反趋势CxHy、CO气体浓度均有所下降,且随热释放速率的增加热降低。90 kPa工况下电池燃爆更为剧烈,作为物质完全燃烧的证明,CO2气体浓度高于50 kPa工况下试验值,最高体积分数可达1.5107%。

Characteristics of gases emission during lithium-ion batteries thermal runaway at high plateau

 In order to investigate the effectiveness of low-pressure and low-oxygen environment in high altitude airport on the parameters of jet flame temperature, heat release rate and flue gas composition in the thermal runaway behavior of lithium-ion batteries, the low-pressure test platform of lithium-ion battery was established to simulate the thermal runaway in high altitude airport (50 kPa) and plain airport (90 kPa) respectively. Four 18650 lithium-ion batteries were used as the experimental objects. The results showed that under the condition of 50 kPa, the damage degree of the cell, the heat release rate and the temperature of the jet flame decreases, among which the peak temperature of the jet flame reduces by about 241.3 ℃. Under the condition of 50 kPa, the concentration offlammable gases like C_xH_y and CO in the pyrolysis flue gas is higher, the highest concentration can reach 3 134.50×10^-6 and 0.860% respectively, which increases with the increase of heat release rate.Under the condition of 90 kPa, the concentration of C_xH_y and CO decreases, which decreases with the increase of heat release rate. The combustion and explosion of the batteries is more violent under the condition of 90 kPa. The concentration of CO₂ gas is the proof of the complete combustion of the substance. The highest concentration of CO₂ gas under 90 kPa can reach 1.510 7% and it is higher than that under 50 kPa.