When the second measurement voltage value is equal to or greater than a prescribed second reference voltage value, this means that the overvoltage prevention process having been performed through steps S100 to S300 is not normally performed or the overvoltage continuously occurs in at least one or more cells which correspond to the first measurement voltage value and in which the overvoltage occurrence is not caused by overcharge.

Accordingly, in order to reduce the voltage of the at least one or more cells that are determined to be overvoltage, the balancing FET may be controlled to be turned on through the balancing FET turn-on output step S600.

As described with reference to FIG. 2, this process may be performed by the overvoltage determination unit 154. As a turn-on signal is output to the balancing FET 162, a current of at least one or more cells corresponding to the second measurement voltage value that is determined to be overvoltage may flow to the balancing resistor 164. Accordingly, a dangerous cause due to the overvoltage may be prevented by performing the overvoltage discharge step S700 in which the overvoltage is discharged, namely, overvoltage energy is discharged in the balancing resistor 164, and then the voltage is reduced.

The present invention has been described using preferred embodiments. However, it is to be understood that the scope of the present invention is not limited to the disclosed embodiments. In addition, it should be understood that all changes or modifications derived from the definitions and scopes of the Claims and their equivalents fall within the scope of the present invention.