Mathematical Modeling for Reconfigurable Battery Systems With Parallel–Series Connections

Utilizing controllable switches in battery systems can provide flexible and dynamic configurations for batteries at the cell, bank, and pack levels. The reconfigurable battery packs (RBPs) enable optimization of connection configurations with respect to the overall performance, safety, and lifetime. Despite multiple topologies and control strategies previously proposed in the literature, the quantitative analysis and systematic performance evaluation of RBP dynamics remain challenging due to the absence of a mathematical model at the pack level. To bridge this gap, this work introduces a unified modeling framework for various RBPs. We first develop logic gate-based mappings between the operation of batteries and controllable switches, allowing for the isolation or connection of any battery cell or bank. Following this, we develop detailed battery models in state-space form from cells to complete packs. Illustrative and experimental results show that these models are able to accurately and efficiently capture the internal states of RBPs, such as the state-of-charge (SOC), voltage, and current distribution of individual cells under different scenarios. This novel modeling framework and its internal models can significantly simplify the analyses, design, and management of RBPs.