Modeling and Simulation of Active Cell Balancing using Buck-Boost Converter Approach

Abstract

Lithium-ion batteries in multi-cell configurations often develop state-of-charge (SOC) imbalances, reducing capacity and posing safety risks. This study investigates active cell balancing using the buck-boost conversion principle in a four-cell MATLAB/Simulink model. The balancing performance was evaluated under three operating conditions: static mode, charging, and discharging. In static mode, SOC deviation dropped from 22% to 1.5% within 80 seconds, with balancing current decaying from 2 A as equalization progressed and voltage remaining stable between 3.7 and 3.8 V. During charging, deviation decreased from 15% to 1.5% in 110 seconds, with current peaking at 4.8 A and voltage rising from 3.94 to 4.05 V. In discharging, deviation reduced from 15% to 1.5% in 115 seconds, with current ranging between −4 A and −1 A and voltage decreasing from 3.65 to 3.42 V. The results suggest that the proposed approach demonstrates competitive SOC equalization speed relative to passive balancing methods reported in the literature, with voltage remaining stable across all tested conditions. These findings provide practical insight into the behavior of buck-boost active balancing under realistic operating scenarios and can serve as a useful reference for implementing active balancing in battery management systems for electric vehicles and renewable energy applications.