Improving of Active Cell Balancing by Equalizing the Cell Energy Instead of the Cell Voltage

This article presents how active charge balancing of energy storage devices such as batteries and supercaps can be improved by using the capacity and the state of charge instead of the cell voltage as balancing criterion. Both for charging and discharging an improvement of performance is gained when using the state of charge and the capacity of the cells as information. A battery stack is modeled and a realistic driving cycle is applied to compare the difference between both methods in terms of usable energy. Finally, the simulation is validated by measurements.