However, when only a typical scheme like FIG. 1 is used, for example, when an overvoltage state is misjudged by malfunction of the MCU 14, which determines whether a cell is overvoltage or not only using a measurement voltage value of the cell, there is a limitation such that a problem occurrence caused by overvoltage is not prevented according to various reasons including a case where the current inflow path 16 is not normally cut off, although the MCU 14 outputs a cutoff signal for cutting off the inflow of the charge current, or a case where overvoltage is not caused by overcharge, in contrast with a typical case where overvoltage is mainly caused by overcharge.

Accordingly, the present invention additionally provides a circuit for preventing overvoltage to enhance stability of prevention of overvoltage occurrence in a battery.

A detailed description will be provided with reference to FIG. 2 in which an overcharge protection system according to an embodiment of the present invention is schematically illustrated.

In relation to FIG. 2, the overcharge protection system according to an embodiment of the present invention includes a plurality of battery cells Cell 1 to n, 110, a voltage measurement unit 150, a first control unit 130, a cutoff unit 140, a second control unit 150, and a cell balancing unit 160.