过放对电池鼓胀和再充放电性能的影响

本文深入研究了过放电对锂离子电池性能的影响，并进行了机理研究。结果表明，过放会导致电池鼓胀，且使电池的再充放电性能恶化。这可以被解释为：作为负极集流体的铜箔，在电池发生深度放电的时候会发生氧化，并且在再充电的过程中在负极发生还原，形成一层铜膜，因而大大降低了电池效率，并且SEI膜由于发生过量的锂离子脱出而发生分解和重整，释放出的二氧化碳等气体导致电池发生鼓胀。本文通过实验表明，向LiCoO2正极中加入20%的Li(Ni1/3Co1/3Mn1/3)O2时，可以提高电池的过放性能，即可以使电池的气胀现象消失，且电池鼓胀率显著降低，再充放电能力也显著得到提高。

Effect of Overdischarge on Swelling and Recharge Performance of Lithium Ion Cells

Effects of overdischarge on characteristics of lithium ion cells were deeply studied, and experiments have been made to reveal its mechanisms. The results suggest that overdischarge may result in large swelling of cells and degradation of recharge capabilities. The mechanism can be explained as that: a copper foil used as an anode collector will be oxidized to copper ion when deep overdischarge occurs and reduce at the anode in recharging progress, which greatly deteriorates the cell efficiency; solid electrolyte interface (SEI) film is to decompose and reform because of excessive de‐intercalation of lithium ions, and the released gas such as carbon dioxide makes the cell bulge. The experimental results prove that when 20% Li(Ni_1/3Co_1/3Mn_1/3)O₂ was added to LiCoO₂ cathode materials, the cell swelling rate could be greatly reduced, and the recharge capability would be enhanced much.