储能科学与技术2024，Vol.13Issue(6)：2044-2053,10.DOI:10.19799/j.cnki.2095-4239.2024.0009
镍钴锰三元锂离子电池不同电压下浮充失效机理及热安全研究
Study on the failure mechanism and thermal safety of nickel-cobalt-manganese ternary lithium-ion cells after float-charging at different voltages
摘要
Abstract
Ternary lithium-ion cells,recognized for their superior electrochemical properties,are extensively utilized in the energy storage sector.This research uses commercial 18650 lithium nickel-cobalt-manganese(NCM)/graphite cells as experimental samples to explore the effects of float-charging at 4.2,4.4,and 4.6 V.We conducted a series of analyses including capacity tests,incremental capacity analysis,and impedance tests,complemented by X-ray diffractometry(XRD),X-ray photoelectron spectroscopy(XPS),and scanning electron microscopy(SEM)of electrode materials from disassembled cells.The influence of float-charging on thermal safety of NCM cells was studied through the accelerating rate calorimeter(ARC)test.Our findings indicate that higher float-charging voltages accelerate cell aging,with an average capacity loss rate of 1.166%/day at 4.6 V.Float-charging at elevated voltages intensifies the interface reactions between the electrolyte and electrode,resulting in a thicker solid electrolyte interface(SEI)film and a substantial increase in impedance.Furthermore,it induces corrosion of the positive collector,leading to aluminum precipitation and deposition at the negative electrode,which further accelerates the capacity attenuation.The onset temperature of self-heating(Tonset)of the cells is reduced after float-charging,indicating a decrease in thermal safety.Through float charging process analysis,failure material characterization,and thermal runaway experiments,this study provides theoretical insights and technical guidance on the impacts of float-charging on the electronic and thermal safety performance of lithium-ion cells.关键词
锂离子电池/浮充/热失控/失效机理/热安全性Key words
lithium ion cell/float-charging/thermal runaway/failure mechanism/thermal safety分类
信息技术与安全科学引用本文复制引用
汤旭旭,许铤,储德韧..镍钴锰三元锂离子电池不同电压下浮充失效机理及热安全研究[J].储能科学与技术,2024,13(6):2044-2053,10.基金项目
上海市科委项目(23DZ2200800) （23DZ2200800）
上海市国资委项目(2021012). （2021012）
