一种锂离子蓄电池过充保护添加剂的研究

Cyclohexylbenzene as overcharge protection additive in lithium ion batteries

为了进一步改进锂离子蓄电池的安全性能,研究了在液体电解质中添加环己烷苯(Cyclohexylbenzene,简称CHB)的过充保护作用。对电池进行了恒流充放电和过充实验、循环伏安扫描测试和容量特性测试。实验数据显示,在1mol稝L-1LiPF6/EC+DEC+DMC(体积比1∶1∶1)中添加CHB2.5%和5%(质量分数)时,当外加电压在4.3～5.0V范围内,CHB生成了导电聚合物膜,使正在充电的电池内部形成短路而发生自放电,可把电池电压控制在4.5～4.8V,从而处于更安全的充电状态。在该体系正常充放电过程中,添加CHB对电池容量特性没有不利影响。所以CHB是锂离子蓄电池优良的过充保护添加剂。

In order to further improve the safety performance of lithium ion batteries, cyclohexylbenzene （CHB） was investigated to be an overcharge protection additive for non-aqueous liquid electrolyte in lithium ion batteries. Proved by overcharge of batteries, cyclic voltammetry tests and battery power capacity measurements in this research, certain conclusions were obtained. When the external potential ranges from 4.3 V to 5 V, CHB （2.5% or 5% by mass） in the system of electrolyte 1 mol·L^-1LiPF6/EC＋DEC＋DMC （1 ： 1 ： 1 by volume） can produce the conductive polymer film, creating the short-circuit between the positive and negative electrodes and causing self-discharge. Therefore the cell＇s potential can be controlled between 4.5-4.8 V, and the lithium ion batteries can be much safer when overcharged. Meanwhile, during the normal charge-discharge process of the battery system, the addition of the proper weight percentage of CHB does not have negative effect on the capacity character of lithium-ion battery. All these advantages promise CHB to be an ideal overcharge protection additive in lithium ion batteries.