For high-power, multi-cell lithium-ion battery applications, one important aspect to managing the battery is the cell-balancing scheme. Due to a variety reasons, multiple cells connected in series will tend to drift apart in voltage from one another, which results in a loss in battery capacity or overcharge or overdischarge, which can both be hazardous. To overcome this, a balancing circuit is adapted to the battery and used to keep the cell voltages close together. Several approaches developed in the past have included many drawbacks which necessitated the development of a new approach.

The approach developed here is modular and can be applied to virtually any size battery, providing a fast and efficient method to keeping cells in balance. It uses a flying capacitor to move charge selectively from a cell with the highest charge to a cell with the lowest charge, repeating this process as long as any cell deviates from the mean of the whole battery. A bidirectional power converter manages the charge movement and speeds up the balancing process. This research presents an efficient, fast, and easily scalable solution to maintaining battery cell balance.