空间用锂离子电池储存寿命衰降机理分析

Mechanism of calendar life decline of space lithium ion batteries

锂离子电池在存储的过程中由于界面副反应的存在,会导致活性Li的消耗和内阻的增加(界面膜增厚),引起锂离子电池可逆容量的损失。分析表明,空间用NCA/石墨高比能电池在3.5V状态下存储1年,正极容量损失仅为1%,倍率性能没有受到影响。负极在存储过程中电解液会在其表面发生分解,使负极的接触阻抗和电荷交换阻抗增加50%左右,对电池倍率性能产生一定的影响,但可逆容量没有降低,3.5V存储会造成电池轻微容量降低和倍率性能下降。

The side reaction in the interface between the electrode and electrolyte will cause the loss of active Li and the increase of interface resistance(thickening of interface),and the reversible capacity will decrease as a result.The analysis indicates that the reversible capacity of cathode of high energy space lithium batteries decreases less than 1%without ratio performance decreasing after one year storage at 3.5 V.The surface resistance of anode increases more than 50%as a result of electrolyte decomposing on the surface of anode.This change has no influences on the reversible capacity,but the ratio performance decreases slightly.The storage at 3.5 V will result in the reversible capacity and ratio performance decreasing slightly.