A novel charge and discharge equalization scheme for battery strings

A novel charge/discharge equalization scheme is proposed in this paper. According to the states of batteries, two equalizing methods are adopted for equalization during different charging and discharging phases. A switched capacitor is utilized during high rate charging and discharging. During the later period of charging and discharging, an auxiliary low power DC/DC converter and the inherent switch modules of a control/monitor unit are used. So it is very simple and efficient. With the developed equalizer, the lifetime of a series battery string can be extended.