| 摘要 |
PROBLEM TO BE SOLVED: To double a protection means for an overcurrent or an overheat without providing protection elements, such as polymer PTC elements, etc. in series with the charge/discharge route of the battery cell, and without providing a third switch element controlled by a thermistor of positive characteristic or negative characteristic. SOLUTION: A first switch element 4a which cuts off a discharge current flowing to the battery cell 1, and a second switch element 4b which cuts off a charge current flowing to a first switch element 4a, are provided. A positive characteristic thermistor Rcpb is inserted between the gate control terminals Dout, Cout of a protection control circuit 3 and at least one gate of the switch elements 4a, 4b. And, a resistor R1b is connected between the gate and the source of the switch element. The positive characteristic thermistor Rcpb is thermally coupled with first/second switch element 4a/4b or the battery cell 1. Consequently, in the abnormal overheat state of the switch elements 4a, 4b or the battery cell 1, the switch element 4b becomes a cut-off state by the resistance value rise of the positive characteristic thermistor Rcpb, and a protecting function operates. COPYRIGHT: (C)2006,JPO&NCIPI |
