Performance degradation investigation of lithium iron phosphate and ternary lithium-ion batteries under slight electrical abuse condition
WEI Gang
HUANG Ranjun
JIANG Bo
CAI Jixiang
XU Wentao
ZHU Jiangong
WANG Xueyuan
WEI Xuezhe
DAI Haifeng
Abstract：Currently,lithium-ion batteries are widely used in clean transportation and scale energy storage applications,however,due to the inherent variability in the consistency of batteries manufacture and the capacity degradation rate in service,the batteries are often subjected to slight overcharge during operation,and the cyclic accumulation effect caused by further delayed maintenance will pose the reliability challenge and safety hazard to the large-scale group application of batteries,therefore it is valuable to investigate the performance degradation of the main battery types under the mentioned conditions.In this paper,normal cycle aging and slight overcharge cycle aging tests were conducted on lithium iron phosphate and nickel-cobalt-manganese ternary lithium-ion batteries.The results show that the performance degradation characteristics of lithium iron phosphate batteries under two cycle conditions are quite small,while the performance degradation of ternary batteries under slight overcharge cycle condition is much faster than that under normal cycle condition.Combined with electrochemical impedance tests and analysis methods such as equivalent circuit models and distribution of relaxation times,it is revealed that the main cause of the significant degradation of state of health for ternary batteries under the slight overcharge cycle condition is the more severe loss of lithium inventory due to the increase of the solid electrolyte interphase equivalent resistance and the charge transfer resistance.In contrast,the lithium iron phosphate batteries are more tolerant to the slight abuse cycle condition,with little change in the solid electrolyte interphase equivalent resistance and charge transfer resistance,and limited loss of lithium inventory,resulting in no more serious performance degradation compared with the normal cycle condition for the set number of cycles.
Keywords：lithium-ion batteryslight electrical abuseovercharge cycleperformance degradationelectrochemical impedanceequivalent circuit modeldistribution of relaxation times
Publication Date：2025-04-25
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：12( 110-121 )