Patent ID: 7531988

Claim:
A battery pack including at least a battery cell and a protection circuit for shutting off a overcurrent discharge, comprising: a discharge control switch connected between a negative terminal of the battery cell and an external minus terminal is configured to close after the detection of the overcurrent discharge; a shut-off holding unit configured to maintain a discharge shut-off condition after the detection of an the overcurrent discharge due to the shorting or connection of a low resistance between a external plus terminal and a external minus terminal of the battery pack; and a releasing unit configured to release the discharge shut-off condition maintained by the shut-off holding unit by applying a predetermined voltage between the external plus terminal and the external minus terminal of the battery pack, wherein, said discharge control switch is one of a mechanical switch, a transistor, and a field effect transistor, an inductor, a first capacitor, a second capacitor, and a diode are provided as the releasing unit for releasing overcurrent discharge shut-off, the inductor and the first capacitor are connected in series, the other end of the inductor is connected to the external plus terminal, the other end of the first capacitor is connected to the external minus terminal, the second capacitor is connected to the junction of the inductor and the first capacitor, the other end of the second capacitor and the anode of the diode are connected in series, and the cathode of the diode is connected to the switch control terminal of the discharging control switch.