Comparative Simulation and Performance Analysis of Passive and Active Cell Balancing Topologies in Battery Management Systems for Electric Vehicles

Abstract

Over the last decade, the proliferation of electric vehicles (EVs) has highlighted the importance of robust battery management systems (BMSs) to mitigate cell imbalance driven by manufacturing tolerances, thermal gradients, and non-uniform aging. To address these limitations, this study presents a MATLAB R2023b/Simulink-based comparative performance analysis of passive and active cell balancing topologies for lithium-ion battery packs. Using an equivalent circuit model based on the ORION 18650/26 cell, twelve distinct configurations encompassing passive switched-resistor alongside active inductor, capacitor, transformer, and converter topologies were evaluated. To isolate intrinsic charge-transfer dynamics from multi-cell network latency, all topologies were benchmarked in a standardized adjacent two-cell baseline under a strict convergence threshold (ΔOCV ≤ 1 mV). The simulation results demonstrate that parallel two-inductor and buck–boost topologies achieve the fastest equalization speed (≈1.47–2.53 s), whereas switched-capacitor configurations yield the lowest total energy dissipation (≈0.0011 Wh–0.0013 Wh). Furthermore, to evaluate string-level scalability and multi-hop energy transfer dynamics, the high-performing buck–boost topology was extended and benchmarked in a four-cell series (4S) configuration. The simulation results demonstrate that while the adjacent two-cell baseline achieves fast equalization (≈1.47–2.53 s), the 4S string reaches multi-cell convergence within 12.47–13.94 s, providing quantitative insights into multi-hop routing latency. Overall, this work provides an unconfounded quantitative baseline to support BMS engineers in selecting optimal balancing topologies tailored to specific EV performance, space, and economic constraints.