Energy-efficient and High Speed Active Cell Balancing Methodology for Lithium-ion Battery Pack

Battery packs are used in several emerging applications such as electric and hybrid electric vehicles, drones, and satellites, etc. The battery pack consists of multiple series and parallel connected cells in order to provide the required output voltage and the current capacity. The status of the battery pack depends on the weakest cell, i.e., the cell having the lowest capacity and State-of-Charge (SOC). This necessitates charge transfer among the cells to maintain equal SOC of all the cells, avoid wastage of energy, prevent degradation, and improve the overall efficiency of the pack. This article introduces an energy-efficient, high-speed, and accurate active cell balancing methodology that involves cell-to-cell and cell-to-load balancing for the battery pack. The proposed bidirectional flyback converter-based, PID-controlled active cell balancing methodology has low power consumption compared to state-of-the-art cell balancing methodologies. Simulation results show that the average balancing speed for both cell-to-load and cell-to-cell balancing has been improved by 2.75 times compared to the state-of-the-art methodologies while maintaining very low power consumption. Average power consumption during cell balancing has been reduced by 7.2 times and the average balancing accuracy is improved by 11.88% compared to the state-of-the-art methodology.