Abstract:

Overdischarge of the Li-NiCoMnO2 (NCM) batteries causes internal short circuit. The overdischarged battery has the ability of self-healing during the storage process. The overdischarged NCM batteries were investigated to further clarify the characteristic of overdischarged battery. The overdischarged NCM batteries
were firstly rested for 100-day and followed by 20 cycles and 3-day rest. The results indicate that the capacity of overdischarged battery cells degraded during the storage. No matter to what extent the NCM batteries was overdischarged, the internal short circuit level decreased while the ISC resistance rose, and the leakage current droped after the 100-day rest of the overdischarged batteries. The cycle life test after storage proved that the higher degree of the overdischarge, the faster a battery capacity faded. The performance of the battery after overdischarge is helpful to understand the characteristics of the battery, and it is also helpful to the verification of the algorithm for the identification of the short circuit resistance

Key words: lithium batteries, self-healing, overdischarge, leakage current, short circuit resistance, cycle capacity