SOC-Balancing Circuit Based on a Resonant Switched-Capacitor Converter for Battery Modules

The state-of-charge (SOC) imbalance in series-connected battery modules remains a critical challenge for battery energy storage systems, leading to reduced efficiency, accelerated degradation, and even the risk of explosion. This paper proposes a series-connected battery module SOC balancing strategy based on a resonant switched-capacitor converter (RSCC). It also analyzes the operating principles under phase-shift control for both two-module and multi-module configurations. For SOC balancing across multiple battery modules, the implementation of switch sharing enables a reduction in the number of required power devices compared to conventional non-shared switching type. To validate the operation of SOC balancing strategy, a simulation model through MATLAB/Simulink with a lithium-ion battery stack is performed. The simulation reveals that the proposed strategy can control SOC deviation within the set range. Therefore, this research provides a scalable solution for series-connected battery modules in renewable energy integration, offering theoretical significance value in next-generation energy management systems.