Comparative Study on the Battery State-of-Charge Estimation Method

Abstract

Accurate SOC (State-of-Charge) estimation has been an important part for all applications including energy storage systems. The accurate SOC estimation protects a battery to be deeply discharged and over-charged. Many studies on SOC estimation methods have been developed for evaluating more accurate SOC value. The battery SOC can be influenced by the battery temperature, the type of battery and the external conditions. Because of these reasons, SOC estimation methods differ from battery applications such as energy storage system, hybrid electrical vehicle or electrical vehicle. This paper analyzes and compares the strengths and weaknesses of typical estimation methods which have been studied by researchers. By comparing these advantages and disadvantages of various methods, this paper presents proper estimation methods suitable for energy storage applications.Keywords: Ampere Hour Counting, Electrochemical Impedance Spectroscopy, Open Circuit Voltage, Kalman Filter, SOC (State of Charge)