A battery pack is disclosed. In one aspect, the battery pack includes a battery unit including a plurality of main battery cells and an additional battery cell. The battery pack also includes a battery management system (BMS) configured to receive voltage information about the battery unit and control charging and discharging of the battery unit. The BMS includes at least one voltage measuring terminal configured to receive main voltage information about the main battery cell and an analog to digital converting terminal configured to receive additional voltage information about the additional battery cell.