Dual and Joint EKF for Simultaneous SOC and SOH Estimation

A battery management system for HEV/BEV application must perform a number of estimation tasks in real time. In previous papers, we have presented methods for cell SOC estimation that use extended Kalman filters (EKF) as their basis. In this paper, we show how EKF may also be used to estimate power fade, capacity fade, and can keep the SOC estimate accurate throughout the lifetime of the cell, even though its dynamics change as it ages. Results are presented to demonstrate the efficacy of the new methods. Copyright 2005 EVS21