涉水锂离子电池的腐蚀与析氢风险研究

Study of corrosion and hydrogen evolution risk of waded lithium ion-battery

锂离子电池涉水事件频发,特别是沿海地区及海事应用方面常常遇到高盐度涉水事件。以18650型电池为样本,进行不同盐度条件下涉水锂离子电池的腐蚀与析氢风险实验研究。结果表明:锂离子电池涉水时首先发生电解和电化学腐蚀现象,盐度越高,这种现象越显著;腐蚀主要发生在阳极帽处,随着腐蚀进行,腐蚀孔向内部深入,直至电池彻底损坏;涉水中锂离子电池的质量损失速率与电压降呈正相关关系;腐蚀产物主要为氢氧化亚铁、氢氧化铁和氢氧化铝;涉水过程中阴极析出大量氢气,氢气产生速率与盐溶液浓度呈正相关关系;对于较封闭的应用环境极易达到氢气爆炸下限;轻度腐蚀后电池热失控过程的喷射程度较为剧烈,燃爆危险性较高;而过度腐蚀则会直接破坏电池结构,进而使电池完全失效。

Lithium-ion battery wading events occur frequently,especially,often suffering high salinity wading events in coastal areas and maritime operations.In this paper,18650 model batteries were used as samples to carry out experiments on the risk of corrosion and hydrogen evolution of waded lithium-ion batteries under different salinity conditions.The findings indicate that soaking lithium-ion batteries in an aqueous sodium chloride solution triggers the onset of electrolytic and electrochemical corrosion.The higher the salinity of the solution,the more significant this phenomenon is.The corrosion mainly occurs at the anode cap.With corrosion developing,the corrosion hole goes deep into the interior until the battery is completely damaged.There is a positive correlation between the mass loss rate and voltage drop of lithium battery in the wading process.Aluminum hydroxide,ferrous hydroxide,and ferric hydroxide make up the majority of the corrosion products.In the process,a large amount of hydrogen emerges from the cathode,and the hydrogen generation rate has a positive linear relationship with the concentration of salt solution.For relatively narrow space,it is very easy to reach the lower limit of a hydrogen explosion.After mild corrosion,the injection degree of the thermal runaway process of the battery is more severe,and the risk of combustion and explosion is relatively high.Furthermore,extreme corrosion will directly damage the battery's construction,rendering it totally useless.