车用镍钴锰三元锂离子电池过放电后的性能实验研究

摘要

锂电池过放电后会诱发内短路,短路电池单体搁置过程中会存在一定的自修复现象.为了对电池过放电的特性进行进一步的研究,以获得过放电电池的电特性,本文以过放电后的镍钴锰(LiNiCoMnO2,NCM)三元锂电池单体为研究对象,过放电后搁置100 d,再对电池进行20次循环充放电试验和静置试验.实验结果表明,搁置过程中电池单体的容量有衰减;无论过放至何种程度,过放电后的NCM锂电池单体在搁置100 d的前后对比中,内短路程度降低,内短路阻值变大,漏电流变小.搁置后的循环寿命实验表明,过放电程度越大的电池单体衰减速率越快.这些过放电后电池单体的性能变化规律有助于更深入地了解锂离子电池单体的特性,同时,也有助于电池短路电阻辨识算法的验证.%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.