A battery pack comprising: a battery cell; a secondary core unit comprising an induction coil (Scoil) configured to induce a power signal from a magnetic field applied thereto, a secondary rectification unit coupled to the induction coil (Scoil) and configured to rectify the induced power signal to generate a rectified power signal; an object detection unit having a switch, the object detection unit being configured to receive the rectified power signal and transfer the rectified power signal to a charging control unit through the switch; the charging control unit configured to perform both control of charging and discharging of the battery cell using the rectified power signal received from the object detection unit, and generation of a charge state information and periodically recording the generated information while monitoring the charging state of the battery cell; a protection unit coupled between the charging control unit and the battery cell, and configured to adjust charging and discharging of the battery cell depending on whether the battery cell is to be charged or discharged; and wherein, the object detection unit is configured to: detect instantaneous power at the same time that the battery pack is placed on a non-contact charger; allow a no load state to be maintained by maintaining a switch in an OFF state for a certain period of time; allow the no load state to be switched into a load state by maintaining the switch in an ON state after the no load state has been maintained for the period of time, thereby informing a primary coil of the non-contact charger through load modulation that the battery pack has been placed on the non-contact charger and, at the same time, apply power to the charging control unit. a battery cell; a secondary core unit comprising an induction coil (Scoil) configured to induce a power signal from a magnetic field applied thereto, a secondary rectification unit coupled to the induction coil (Scoil) and configured to rectify the induced power signal to generate a rectified power signal; an object detection unit having a switch, the object detection unit being configured to receive the rectified power signal and transfer the rectified power signal to a charging control unit through the switch; the charging control unit configured to perform both control of charging and discharging of the battery cell using the rectified power signal received from the object detection unit, and generation of a charge state information and periodically recording the generated information while monitoring the charging state of the battery cell; a protection unit coupled between the charging control unit and the battery cell, and configured to adjust charging and discharging of the battery cell depending on whether the battery cell is to be charged or discharged; and wherein, the object detection unit is configured to: detect instantaneous power at the same time that the battery pack is placed on a non-contact charger; allow a no load state to be maintained by maintaining a switch in an OFF state for a certain period of time; allow the no load state to be switched into a load state by maintaining the switch in an ON state after the no load state has been maintained for the period of time, thereby informing a primary coil of the non-contact charger through load modulation that the battery pack has been placed on the non-contact charger and, at the same time, apply power to the charging control unit. detect instantaneous power at the same time that the battery pack is placed on a non-contact charger; allow a no load state to be maintained by maintaining a switch in an OFF state for a certain period of time; allow the no load state to be switched into a load state by maintaining the switch in an ON state after the no load state has been maintained for the period of time, thereby informing a primary coil of the non-contact charger through load modulation that the battery pack has been placed on the non-contact charger and, at the same time, apply power to the charging control unit.