Extension of battery life via charge equalization control

The primary difficulty in charging storage batteries is in attaining process regulation that allows fast charging while avoiding destructive overcharging. A two-level approach to controlling the charging process is presented. A general background discussion of batteries and charging problems is followed by the presentation of a novel recirculating charge equalization technique that enhances the uniformity of batteries made up from long serial strings of cells. A straightforward means of embedding equalization within an outer-loop supervisory control that maintains a fast charging rate while providing overall protection against overcharging is briefly described. Simulation and experimental results confirm the applicability of the equalization control technique