A battery overcharge preventing device according to an embodiment of the present invention includes: a voltage distribution unit connected to both ends of at least one battery cell in a battery module including multiple battery cells, the voltage distribution unit being configured to distribute a voltage of the at least one battery cell according to a preset ratio; a voltage sensing unit operating so as to allow a control current to flow when the voltage distributed by the voltage distribution unit is greater than a preset reference voltage; and a second relay configured to block, by operation of the voltage sensing unit, operation of a first relay that establishes an electrical connection between the battery module and a charging module.