PROBLEM TO BE SOLVED: To provide a protection circuit that can realize high safety by surely shutting off a charge/discharge circuit of a secondary battery.
SOLUTION: A protection circuit 1A includes a protective element 10A, a plurality of secondary battery cells 20, 20, ... an external positive electrode terminal 30a, an external negative electrode terminal 30b, an auxiliary power supply 40, a first control device 50, and a switch 60. The protection element 10A includes a first soluble conductor 15 with both ends connected to a first terminal 11 and a second terminal 12, and a heating element 16 installed in a first energization path P1A between a third terminal 13 and a fourth terminal 14. The auxiliary power supply 40 is electrically independently provided with a plurality of secondary battery cells 20,20, ... and in this protection circuit 1A, the switch 60 is switched to be energized by a signal from the first control device 50; the heating element 16 of the protection element 10A generates heat; and the first soluble conductor 15 is melted to cut off between the plurality of secondary battery cells 20, 20, ... and the external negative electrode terminal 30b.
SELECTED DRAWING: Figure 1
COPYRIGHT: (C)2022,JPO&INPIT
