Design and validation of a multi-layer multi-inductor active cell balancing architecture for eight-cell lithium-ion battery packs

Electric cars are becoming increasingly popular very quickly. This has increased the need for reliable and effective battery management systems, since the performance of the batteries directly affects the range, safety, and lifespan of the vehicle. Lithium-ion battery packs are made up of many cells connected in series. Manufacturing flaws, uneven aging, and working conditions can all cause cells to become imbalanced. These kinds of imbalances can cause capacity loss, thermal stress, and lower total efficiency, which is why active cell balancing strategies are needed. This study proposes a three-layer hierarchical multi-inductor topology and a two-layer optimized multi-inductor topology with a state-of-charge based control algorithm for an eight-cell, 28.8 V lithium-ion battery pack. The suggested designs use a smaller switch network to allow energy movement between cells and between groups on a global level. This speeds up balancing and keeps the hardware simple. To make sure that balancing choices are correct and reliable, a particle filter is combined with a 2RC battery model to estimate SOC. The suggested systems are designed and tested using MATLAB/Simulink. Real-time hardware-in-the-loop (HIL) testing on an OPAL-RT 5700 system verifies their functionality. Simulation and HIL results show that the three-layer architecture balances cells within 55–82 s across static, charging, and discharging. The optimized two-layer design requires 140–170 s but achieves 99% efficiency, illustrating the trade-off between balancing speed and reliability. These results demonstrate that the proposed designs can efficiently, scalable, and quickly balance active cells in lithium-ion battery packs.