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.
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a Divisional application of U.S. Ser. No. 11/612,107 filed Dec. 18, 2006, which application claims the benefit and priority of PCT/JP2005/009326 filed May 23, 2005, which claims priority of JP2004-178440 filed Jun. 16, 2004 and JP2004-206244 filed Jul. 13, 2004, incorporated by reference.
Priority Data
Jun 16, 2004 [JP] 2004-178440 Jul 13, 2004 [JP] 2004-206244
