An insight into battery degradation for the proposal of a battery-friendly charging technique

Abstract

Lithium-ion batteries have become popular for electric vehicles due to their exceptional ability to deliver a high specific power and energy density. However, one of the main drawbacks of these batteries is the inevitable capacity fading that results from degradation over time. The rate at which the capacity of Li-ion batteries fades in EVs is highly dependent on various factors, such as the charging rate, fluctuations in the internal cell temperature, the external ambient temperature, and the driving patterns of the user. Determining the root cause of degradation and constraining its rate in Li-ion batteries, which occurs due to electrochemical processes, remains challenging. This is due to the complex interplay between chemical, electrical, and mechanical parameters that influence the degradation process. The authors of this study have sought to shed light on the causes of degradation by examining the variations in parameters across multiple charge types and rates at different ambient temperatures. While previous research has proposed several charging algorithms aimed at resolving the degradation issue in Li-ion batteries, there is still a need for a unified technique that can effectively constrain the degradation rate at any ambient temperature. This approach should consider the electrochemical phenomena within the battery, grid conditions, and user requirements. The authors of this study have proposed a new battery-friendly charging scheme, which is suitable for the rapid charging of batteries at various ambient temperatures and is effective in mitigating degradation. The study also suggests the suitability of different charging techniques for energy-intensive or power-intensive applications, to provide a comprehensive and systematic approach to developing a new charging technique.