Design and simulation of EV battery management systems

Abstract

This paper introduces a Battery Management System (BMS) for electric vehicles, built around a passive cell balancing strategy. Our aim is to improve the safety and lifetime of the Lithium-Ion battery pack, with a particular focus on cell-to-cell voltage equalization. The proposed system detects voltage disparities between cells and activates a bleeding circuit to equalize the State of Charge (SoC). Furthermore, the model integrates a thermal management system that monitors cell temperature and triggers active cooling when a critical threshold is reached. The originality of the work lies in the co-simulation of the BMS together with a vehicle powertrain whose speed is regulated by a Proportional-Integral (PI) controller, allowing the joint validation of balancing, thermal regulation and safety interlocks under a realistic urban driving cycle. Simulation results demonstrate the effectiveness of the passive balancing logic in converging cell voltages and the system's ability to maintain safe operating conditions during driving cycles.