Preparation method of re-pressing-type PTC self-recovery safety device

The invention provides a preparation method of a re-pressing-type PTC self-recovery safety device. The method comprises the following steps of (1) punching a first U-shaped through groove in a core plate; (2) covering the upper surface with a first upper insulating film and a piece of first upper electrode foil, covering the lower surface with a first lower insulating film and a piece of first lower electrode foil, carrying out lamination and removing the electrode foil; (3) punching a second U-shaped through groove in a mirror image of the first U-shaped through groove in the core plate, covering the upper surface with a second upper insulating film and a piece of second upper electrode foil and covering the lower surface with a second lower insulating film and a piece of second lower electrode foil and carrying out lamination; and (4) etching dicing lines on the surface, corresponding to the first U-shaped through groove and the second U-shaped through groove, of the core plate, carrying out punching on the