New estimation method of state of batteries based on system identification

This paper proposes a new approach for the assessment of battery state using a mathematical model of internal impedance. State of charge and degradation might be estimated by methods using system identification techniques. The final objective of this research is to find out a simple, time and cost effective method. In this paper, the targets of estimation are Ni-Cd, Ni-MH batteries that are widely used in portable equipment, but for which exact state estimation is difficult. In the proposed method, a new signal-processing scheme is used to detect voltage fluctuation of batteries. Using the proposed method and system identification method suitable for batteries, parameters of mathematical model are obtained from experiments. The obtained parameters have sufficient information in order to estimate the state of batteries.