Prediction of overcharge-induced serious capacity fading in nickel cobalt aluminum oxide lithium-ion batteries using electrochemical impedance spectroscopy

Detection of Unbalanced Voltage Cells in Series-connected Lithium-ion Batteries Using Single-frequency Electrochemical Impedance Spectroscopy

“…This behavior is similar to the results obtained from a NMC cathode by Ovejas et al, who reported that the apex frequency of the NMC cathode changes over 2-28 Hz for SOC10%-SOC100%, and is low for low (<SOC40%) and high (>SOC80%) SOCs [6]. In our previous study, where activation energy was calculated using the same battery cell, we reported that the semi-circle with an apex frequency near 1 Hz at SOC100% can be attributed to NCA cathode reactions [1]. Therefore, the semi-circle in the low-frequency region can be attributed to NCA cathode reactions.…”

“…By contrast, the apex frequency corresponding to SEI is typically observed at a few hundred hertz [6,14]. We previously reported that the capacitive semi-circles of the graphite anode and SEI overlapped each other at temperatures of 20 o C [1,15]. Therefore, the semi-circle in the high-frequency region is attributed to the anode reactions, which combine signals from the graphite and SEI.…”

“…High-energy 18650 type cylindrical cells with a capacity of ~2.9 A•h were used throughout this study. The anodes and cathodes in the cells are composed of graphite and nickel cobalt aluminum oxide (NCA), whose details have been investigated in our previous paper [1].…”

“…However, the SOC of each cell in the module can differ slightly during charge-discharge operations, owing to variations in atmospheric temperature or the manufacturing process. Unbalanced SOC cells in the module are potential triggers of an overcharge [1] or an over-discharge [2], which can lead to combustion and explosion. However, these are inherently difficult to identify without external electrical circuits for measuring the voltage of each cell.…”

Three-dimensional clusters of peony-shaped CuO nanosheets as a high-rate anode for Li-ion batteries

“…Among them, lithium ion batteries (LIBs) are by far the most sophisticated devices and are important in both civil and military elds. [1][2][3][4] However, the currently used graphitic anode is limited by its theoretical capacity (372 mA h g À1 ), and it is still hard to meet the demands for high power density devices. 5,6 As an alternative, transition metal oxides (TMOs) are emerging as a promising candidate as anode materials due to their high theoretical density which could endow LIBs with desirable electrochemical performance.…”