Design and Implementation of a Converter-Based Active Battery Cell Equalization System for Electric Vehicles

Abstract: Battery cell balancing is one of the key functions of the Battery Management System (BMS) used in Electric Vehicles (EVs), as it enhances the battery performance while prolonging the battery life as well as providing safety. Battery cells connected in series have different parameters like internal resistance, temperature, and aging effects, which cause the state of charge to be different. This results in the battery capacity being less efficient and can cause battery degradation or safety issues. This paper discusses the different battery cell balancing techniques used in the battery management system. These techniques include passive balancing, switched capacitor equalizers, inductive equalizers, transformer equalizers, and DC–DC converter equalizers. A MATLAB/Simulink model is used to implement the different battery cell balancing techniques and their simulation results compared. A battery cell equalization system based on the Ćuk converter is designed for the battery cells of the Electric Vehicle. Simulation results show that the proposed system balances the charge of the battery cells efficiently with the least time and highest efficiency compared to the other battery balancing techniques.

Keywords: Battery Management System (BMS), Electric Vehicle Batteries, Cell Balancing, Active Balancing, Passive Balancing, Ćuk Converter, Battery Equalization, MATLAB/Simulink.