A battery pack includes a first switching element which shuts off a
discharging current flowing to a battery cell and a second switching
element which shuts off a charging current. A positive temperature
coefficient thermistor is inserted between a gate control terminal of a
protective control circuit and a gate of at least one of the switching
elements, and a resistor is connected between the gate and a source of
the switching element. The positive temperature coefficient thermistor is
thermally connected to one or more of the first and second switching
elements and/or to the battery cell. Thus, an abnormally overheated state
of one or more of the switching elements or the battery cell leads to an
increase in the resistance of the positive temperature coefficient
thermistor causing shut-off of the switching element thereby protecting
the battery pack.