RAC$^+$: Supporting Reconfiguration-Assisted Charging for Large-Scale Battery Systems

While most existing battery cell balancing approaches were posttreatment (i.e., handling diverse voltage levels originating from different battery cell status), a pretreatment approach, called reconfiguration-assisted charging (RAC), was developed, which dynamically attaches a proper number of resistor arrays to each group of battery cells with similar status, preventing battery cell imbalance; note that this pretreatment approach can be used orthogonally with existing posttreatment approaches such as active/passive balancing. Relaxing its impractical assumptions of RAC (e.g., all necessary resistor arrays are deployed in the target system), this article proposes RAC$^+$, which realizes its practical and efficient use for the pretreatment concept of RAC. The experiment results demonstrate that RAC$^+$ achieves the same balancing performance as RAC while reducing the number of required resistors by 69% compared to RAC. The extensive experiment results also show that RAC$^+$ is not only robust to various charging environments, but also proven to be effective in terms of minimizing power loss.