申请人:Murata Manufacturing Co., Ltd.
公开号:EP3855531A1
公开(公告)日:2021-07-28
A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a lithium-cobalt composite oxide having a layered rock-salt crystal structure. The negative electrode includes graphite. An open circuit potential, versus a lithium reference electrode, of the negative electrode measured in a full charge state is higher than or equal to 19 mV and lower than or equal to 86 mV. The full charge state is a state in which the secondary battery is charged with a constant voltage of a closed circuit voltage of higher than or equal to 4.38 V for 24 hours. A potential variation of the negative electrode is greater than or equal to 1 mV when the secondary battery is discharged from the full charge state by a capacity corresponding to 1% of a maximum discharge capacity. The maximum discharge capacity is a discharge capacity obtained when the secondary battery is discharged with a constant current from the full charge state until the closed circuit voltage reaches 3.00 V, following which the secondary battery is discharged with a constant voltage of the closed circuit voltage of 3.00 V for 24 hours.
二次电池包括正极、负极和电解液。正极包括具有层状岩盐晶体结构的锂钴复合氧化物。负极包括石墨。在完全充电状态下测量的负极相对于锂参比电极的开路电位高于或等于 19 mV,低于或等于 86 mV。完全充电状态是指二次电池以高于或等于 4.38 V 的恒定闭合电路电压充电 24 小时的状态。当二次电池从完全充电状态放电的容量相当于最大放电容量的 1%时,负极的电位变化大于或等于 1 mV。最大放电容量是指二次电池从满电状态以恒定电流放电至闭合电路电压达到 3.00 V,然后以 3.00 V 的闭合电路电压恒定电压放电 24 小时所获得的放电容量。