CELL BALANCE DEVICE AND BATTERY SYSTEM

Provided are a cell balance device capable of protecting a switch circuit when an overcurrent flows through the switch circuit so as to prevent the switch circuit from being broken down, and a battery system including the cell balance devices. The cell balance device includes: a plurality of electric accumulator connection terminals to be each connected to one of a node and two terminals of a plurality of electric accumulators connected in series; a voltage hold device connection terminal to be connected to a voltage hold device; a plurality of first switch circuits provided between the plurality of electric accumulator connection terminals and the voltage hold device; a receiving terminal for receiving a synchronization signal; a transmitting terminal for transmitting the synchronization signal; a control circuit for controlling ON/OFF of the plurality of first switch circuits based on the synchronization signal; and an overcurrent detection circuit for detecting an overcurrent flowing through each of the plurality of first switch circuits.