聚合物锂离子蓄电池气胀原因的初步探讨

Study on gas generation during formation and storage processes for manufacturing polymer Li-ion battery

采用气相色谱方法对电池在化成阶段和储存阶段产生的气体进行了分析,初步讨论了聚合物锂离子蓄电池在化成阶段产生气体和储存阶段发生气胀的原因。结果表明,电池在化成阶段产生气体的主要原因是在负极形成固体电解质膜(SEI层)的过程中,电解液溶剂体系发生了分解;而在储存阶段少数电池出现气胀,其原因可能为:(1)由于电池密封性能不好,外界的水分和空气的渗入,导致气体中的CO2显著增加,且同时出现相当量的O2和N2,同时水分的渗入还会破坏SEI层;(2)若首次化成形成的SEI层不稳定,在诸存阶段SEI层被破坏,为了修复SEI层,复又释放出以烃类为主的气体。

The gases generated in polymer Liion battery during formation process and storage process were analyzed by means of gas chromatography (GC), and the reason of the gas generation was discussed. The results show that gas evolution during the formation process is caused by the decomposition of electrolyte solution system when the solid electrolyte interface (SEI) films form on the surface of carbon electrode. There are two factors to cause gas generation during storage process. The first, since the poor sealing performance, external moisture and air may infiltrate into battery, which leads to the CO2 amount increase remarkably while O2 and N2 appears. The moisture infiltrated from the air may destroy the SEI films. The second, if the SEI films formed during the formation process are unstable and destroyed during the storage process, it will generate organic gas in order to reconstruct SEI films.