The overcharge protection method is adding redox pair imidazolyl sodium or dimethyl bromobenzene as overcharge protectant into electrolyte of the battery until reaching its saturated concentration.

• 一种锂离子二次电池过充电保护方法，包括选择氧化还原电对咪唑钠或二甲基溴代苯作为电池的过充电保护剂，添加进电池的电解液中，直至达到氧化还原电对的饱和浓度；