Modeling and Control of a Hardware Efficient Low-Voltage-to-Cell Battery Balancing Circuit for Electric Vehicle Range Extension

This paper proposes a hardware-efficient battery cell balancing circuit for electric vehicles which uses the low-voltage automotive bus as a convenient source and sink for cell balancing current. The proposed circuit uses n+1 bilateral switches and low-power, low-voltage cell balancing DC/DC converters. The circuit can precisely control the voltage and current applied to each cell, eliminating inrush currents. The circuit also allows direct charging of the weakest cells, thereby extending electric range. This paper describes the design and control of the proposed circuit, and presents simulation results for multiple cell balancing scenarios.