Over-current protection device

An over-current protection device, comprising:

• an electrode layer having a top metal layer and a bottom metal layer;
• and
• a heat-sensitive layer contacting the top metal layer and the bottom metal layer, and being laminated therebetween, wherein the heat-sensitive layer exhibits a positive temperature coefficient (PTC) characteristic and comprises:
• a polymer matrix comprising a first fluoropolymer and a second fluoropolymer, wherein:
• the first fluoropolymer has a first melting point and a first melt flow index;
• the second fluoropolymer has a second melting point lower than the first melting point, and a difference between the first melting point and the second melting point is less than 14° C.;
• and
• the second fluoropolymer has a second melt flow index ranging from 0.4 g/10 min to 0.7 g/10 min;
• and
• a conductive filler dispersed in the polymer matrix, thereby forming an electrically conductive path in the heat-sensitive layer.