Comprehensive Degradation Analysis of NCA Li-Ion Batteries via Methods of Electrochemical Characterisation for Various Stress-Inducing Scenarios

Abstract

Lithium-ion (Li-ion) batteries with Ni-based cathodes are leading storage technology in the fields of electric vehicles and power-grid applications. NCA (LiNiCoAlO2) batteries are known for their troublesome degradation tendencies, and this susceptibility to degradation raises questions regarding the safety of their usage. Hence, it is of vital importance to analyse the degradation of NCA batteries via methods which are applicable to onboard systems, so that the changes in the battery’s state of health can be addressed accordingly. For this purpose, it is crucial to study batteries stressed by various conditions which might induce degradation of different origins or magnitudes. Methods such as electrochemical impedance spectroscopy (EIS), galvanostatic intermittent titration technique (GITT), and incremental capacity analysis (ICA) have been used in battery research for years, however, there is a lack of published studies which would analyse the degradation of NCA batteries by simultaneous usage of these methods, which is essential for a comprehensive and confirmatory understanding of battery degradation. This study intends to fill this research gap by analysing the degradation of NCA batteries via simultaneous usage of EIS, GITT, and ICA methods for common stress-inducing operating conditions (over-charge, over-discharge, and high-current charging).

Keywords

• Li-ion battery
• NCA
• degradation
• EIS
• ICA
• GITT