A Review of SOH Estimation Methods in Lithium-ion Batteries for Electric Vehicle Applications

Aging of lithium-ion cells is an inevitable phenomenon limiting the lifetime in electric vehicle (EV) applications. Undesirable side reactions during cycle or calendar aging may affect the performance of the batteries. This results in a decreased capacity and an increase in the cell impedance. Furthermore, the aging phenomena are highly complicated to characterize due to the coupling of different factors. In this review, various aspects of recent research and developments, on lithium-ion battery aging mechanisms, analysis and estimations are put forward. To better understand a comparison and summary of techniques, models and algorithms used for battery aging estimation (SOH,RUL), going from a detailed spectroscopy and electrochemical technique to statistical methods based on data are presented in this paper, and their respective characteristics are discussed. In addition some considerations about the ideal method that can be derived from existing methods should be discussed and reported in this paper.