A STUDY ON THE METHODS OF ESTIMATING THE STATE OF CHARGE (SOC) OF BATTERY

Abstract

Batteries are a popular and important item that are utilized as energy sources in a variety of applications. The rise of electric vehicles in the twenty-first century has increased its importance. A battery's state of charge (SoC) is critical information. It is vital to estimate SoC with a reasonable degree of precision. During charge and discharge cycles, lithium-ion batteries change their internal state. The level of charge of a lithium-ion battery changes throughout the charging cycle and is dependent on the internal structure of the components, which can degrade over time. Battery management systems that depend on charge counting and cell voltage monitoring frequently estimate the status of charge. It's difficult to tell what state the battery components are in physically. This work will focus on different methods of estimating SoC. Basically, this study will cover terminal Voltage method, Open Circuit Voltage Method, Coulomb Counting Method and a dynamic method based on Unscented Kalman Filter (EKF). The study will be based on simulation on MATLAB and it will also cover a practical experiment by charging and discharging a battery multiple time. A comparative study of the advantages and drawbacks of the existing methods will be discussed in this work.