Advanced SOC and SOH Estimation Methods for EV Batteries—A Review

Abstract

Electric vehicles (EVs) are getting more attention day by day throughout the world. The EVs are slowly replacing conventional IC engine-based vehicles but the main problem with the EVs is driving range and cost. The driving range is mainly depending on type of the battery and size of the battery pack used in EV. More number of batteries are required for the long driving range, which automatically increases the weight and cost of the EVs. Effective battery management is a requirement to increase battery life. So, the effective and advanced battery management system are essential to manage power flow in the EVs. The effective BMS can provide an exact driving range of EV, battery charging and discharging strategies, and the battery cells voltage balancing. In this paper, extensive work has been done on advanced estimation methods for EV batteries state of charge (SOC) and state of health (SOH). Merits and demerits of each method are clearly mentioned. The comparison made among different methods. Various parameters are taken into consideration while making comparison among different methods. Suggestions are also made for selecting optimal SOC and SOH estimation methods. Various issues and challenges are also listed out for the benefit of carrying out further research.