Patent ID: 7400114

Claim:
A voltage equalizer for equalizing terminal voltages of a plurality of battery elements, comprising: an equalization processing circuit comprising: a transformer including basic windings, the basic windings having a plurality of primary windings and one or more secondary windings, wherein the primary windings respectively correspond to the battery elements; a plurality of switching elements respectively corresponding to the battery elements; a plurality of primary diodes respectively corresponding to the battery elements and respectively in series with the switching elements; one or more secondary diodes corresponding to the secondary windings, wherein a plurality of primary series circuits and one or more secondary series circuits are constituted, wherein a first primary series circuit carries current from a first battery element to a first primary winding, when a first primary switching element provided in the first primary series circuit is switched on, wherein a first secondary series circuit carries current from a first secondary winding to the first batter element, when the first primary switching element provided in the first primary series circuit is switched off, wherein the primary series circuits including the first primary series circuit carry current from the battery elements including the first battery element via the respective primary diodes to the respective primary windings including the first primary winding when the switching elements provided in the respective primary series circuits are switched on, and the secondary series circuits including the first secondary series circuit carry current from the respective secondary windings including the first secondary winding via the respective secondary diodes to the battery elements when the switching elements provided in the respective primary series circuits are switched off; and a control circuit for ON/OFF controlling the switching elements.