Evaluation of Different State of Charge Estimation Techniques for Electric Vehicles

Electric Vehicle (EV) has recently been gaining a great market capital and therefore Battery Management System (BMS) for batteries have become a very crucial aspect for various parameter estimation and proper handling of battery in various environmental conditions. One of the main parameters estimations for BMS is State of Charge (SoC) estimation. The SoC helps to determine the capacity that is remaining inside of the battery at every instance of time and helps to predict proper remaining range and determine the performance of the electric vehicle. Therefore, proper SoC estimation becomes very crucial when it comes to EV. However due to nonlinear and time varying behavior of the battery it becomes quite complex to determine the proper capacity remaining or available in the battery. The modeling of battery, polarization effect on battery is discussed. A comparative study of SoC estimation is done using Open Circuit Voltage method, Columbs Counting method, Kalman Filter sing Matlab and Simulink.