State of health estimation algorithm of LiFePO4 battery packs based on differential voltage curves for battery management system application

摘要

This paper discusses a novel differential voltage curve capacity estimation to determine the state of health of LiFePO4 cells. Differential voltage curves are used because of their ability to detect and quantify degradation mechanisms. The estimation is carried out through partial charging or discharging tests, and is specifically designed for battery management systems, due to the trade off between accuracy and low computational effort. This means the method can be effectively executed online, in a real application. The technique is also able to accurately detect the end of life of the cells.