锂离子电池电极材料的低温特性

采用目前可替换式手机电池常用的方形铝壳锂离子电池,研究电极材料的低温特性。电池正极材料为Li CoO_2、负极材料为大片状2H相石墨、隔膜为单层高密度聚乙烯。电池在低温(0℃)循环(1.0 C充电,0.2 C/0.5 C放电)后,出现析锂、内阻增大、容量减小及鼓包。对电池进行拆解以及对电极沉积物的分析表明:大片状2H相石墨不适合用作在低温环境工作的锂离子电池的负极材料。这类可替换式锂离子电池不适合在低温环境下使用,否则出现鼓包,容易引起安全事故。

Low-temperature performance of electrode materials of Li-ion battery

A prismatic Li-ion battery with aluminum shell,which was widely used as a replaceable cell phone battery was used to study the low-temperature performance of electrode materials.A LiCoO2 positive material,large-flake graphite-2H negative material and a single layer high density polyethylene separator were used.Anomalies as lithium plating,increasing internal resistance,capacity reducing and cell swelling were observed during 0 ℃ low temperature cycle (charge rate:1.0 C;discharge rate:0.2 C/0.5 C).Based on the disassemble of battery and the analysis of precipitate of electrode,large-flake graphite-2H could not be used as the negative material of the Li-ion battery which was often used in low-temperature applications.This kind of battery could not be used under low-temperature or safety accidents could be easily caused by battery swelling.