Abstract: A battery balancing circuit, system and method are disclosed. The battery balancing circuit comprises a plurality of individual batteries, a plurality of first switches, a plurality of second switches, a first control element, a second control element and a transformer. By controlling the first switch and the second switch to be turned on and controlling the first control element and the second control element to be selectively turned on, when the energy in the individual battery is excessive, the excessive energy in the individual battery is transferred to the buffering battery pack; and when the energy in the individual battery is insufficient, the individual battery absorbs energy from the buffering battery pack. In this way, the balance among individual batteries in the battery pack is accomplished and the service life of the battery pack is prolonged.