An Integrated Converter Topology Combing the Battery Charging/Discharging Circuit with the Battery Balancing Circuit

Lithium batteries are widely used in electric vehicles and renewable energy systems. The battery packs are very expensive, while the performances and life time both depend on the characteristics of the charging/discharging circuits and the equalization circuits. Based on bi-directional Buck-boost converter, this paper presents a new converter topology integrating the battery charging/discharging circuit and battery balancing circuit. Compared to traditional circuits, it uses fewer switching devices, simple structure, less power consumption and easy to implement. For battery packs with high capacity and large voltage differences, it can achieve high-current and fast balancing performances during the static and charging period. In addition, this paper describes in detail how to select charging/discharging inductors, balanced inductors and filter capacitors. Simulation results show the effectiveness of the new circuit.