Patent ID: 8129945
Filing Date: 2012-03-06
Classification: H02J,Y02T

Abstract:
1. A system for balancing a state of charge (SOC) of a plurality of cells connected in series, said system comprising: a positive bus and a negative bus; a plurality of positive bus switches with each positive bus switch electrically connected to said positive bus and to one of the cells for electrically connecting said positive bus to a positive side of the one of the cells; a plurality of negative bus switches with each negative bus switch electrically connected to said negative bus and to one of said cells for electrically connecting said negative bus to a negative side of the one of said cells; a charging circuit electrically connected to a voltage source and said busses for charging an undercharged cell of the plurality of cells; said charging circuit including an inductor having a first side electrically connected to said negative bus and a second side electrically connected to said positive bus, a first switch electrically connected to said first side of said inductor and a positive terminal of a voltage source, and a second switch electrically connected to said second side of said inductor and a negative terminal of the voltage source; and a controller in communication with said first and second switches for activating said first and second switches to transfer energy from the voltage source to said inductor and deactivating said first and second switches to transfer energy from said inductor to the undercharged cell of the plurality of cells.