CHARGING AND DISCHARGING CIRCUIT FOR GROUP OF SERIES- CONNECTED BATTERIES

PROBLEM TO BE SOLVED: To provide a charging and discharging circuit for a group of series- connected batteries which enables exclusion of a deteriorated battery or equalization of voltages without interrupting charging and discharging operation by simple configuration. SOLUTION: This circuit is composed of a group of battery units which are obtained by connecting a plurality of series single elements in series. Each of the elements is formed by connecting a battery Bn, a first switching assembly composed of a first diode Dn1 arranged in the forward direction to a charging current Ir and a first switch Sn1 connected in parallel to the first diode, and a second switching assembly each of which is composed of a second diode Dn2 arranged in the reverse direction to the charging current and a second switch Sn2 connected in parallel to the second diode. Further, the element is connected in parallel to one of series single elements, and a control unit which turns off the first switch S11 of a first series single element, turns on the second switch S12 of a second switching assembly after that connected in parallel to the first series single element, and by-passes the battery B1 of the first series single element.