Analysis of Lithium-ion Battery Micro-overcharge Cycle Damage Mechanism Based on Electrochemical Impedance Spectroscopy

Abstract

Electrochemical impedance spectroscopy (EIS) was used to study the micro-overcharge cycle damage mechanism of Lithium-ion batteries (LIBs). Micro-overcharge cycle experiments of LIBs were carried out, and the capacity fading of LIBs under different charging cut-off voltages were analyzed. It was found that the capacity fading rate of LIBs increased with the rising of overcharge cut-off voltages and the increasing of cycle numbers. The EIS results show that the main damage pattern of LIBs during micro-overcharge cycle is the active lithium loss when the cut-off voltage is between 4.3 V and 4.4 V. Lithium loss accounts for more than 80% damage proportion when LIBs cycling for more than 20 cycles.