Pptc device having low melting temperature polymer body

Abstract

A fuse device may include a PPTC body; a first electrode, disposed on a first side of the PPTC body; and a second electrode, disposed on a second side of the PPTC body. The PPTC body may comprise a polymer matrix and a conductive filler, wherein the fuse device has a trip temperature of less than 120° C.

What is claimed is: 
     
         1 . A fuse device, comprising:
 a PPTC body;   a first electrode, disposed on a first side of the PPTC body; and   a second electrode, disposed on a second side of the PPTC body;   wherein the PPTC body comprises a polymer matrix and a conductive filler,   wherein the polymer matrix comprises a polymer having a melting temperature of less than 150° C.   
     
     
         2 . The fuse device of  claim 1 , wherein the polymer matrix comprises a fluoropolymer having a melting temperature less than 150° C. 
     
     
         3 . The fuse device of  claim 2 , wherein the polymer matrix comprises one or more polymers, wherein the one or more polymers comprises a volume fraction of the PPTC body of 35% to 75%, wherein the conductive filler comprises a volume fraction of 25% to 65%, and wherein a volume resistivity of the conductive filler is less than 500 μΩ-cm. 
     
     
         4 . The fuse device of  claim 2 , wherein a hold current density of the PPTC body at 25° C. 0.05 to 0.4 A/mm 2 . 
     
     
         5 . The fuse device of  claim 1 , wherein the polymer matrix comprises a crystalline polyolefin polymer, a polyolefin copolymer, or a combination of a crystalline polyolefin polymer and a polyolefin copolymer, the polymer matrix having a melting point less than 120° C. 
     
     
         6 . The fuse device of  claim 5 , wherein the polymer matrix comprises a volume fraction of the PPTC body of 35% to 75%, wherein the conductive filler comprises a volume fraction of 25% to 65%, and wherein the volume resistivity of the conductive filler is less than 500 μ-cm. 
     
     
         7 . The fuse device of  claim 5 , wherein a hold current density of the PPTC body at 25 C 0.05 to 0.4 A/mm 2 . 
     
     
         8 . The fuse device of  claim 1 , comprising a single layer surface mount device. 
     
     
         9 . The fuse device of  claim 1 , comprising a double layer surface mount device. 
     
     
         10 . A fuse device, comprising:
 a PPTC body;   a first electrode, disposed on a first side of the PPTC body;   a second electrode, disposed on a second side of the PPTC body; and   wherein the PPTC body comprises a polymer matrix and a conductive filler,   wherein the polymer matrix comprises a low temperature PVDF material having a melting temperature in a range between 90° C. and 110° C.   
     
     
         11 . The fuse device of  claim 10 , wherein a hold current density of the PPTC body at 25° C. 0.05 to 0.4 A/mm 2 . 
     
     
         12 . The fuse device of  claim 10 , wherein the polymer matrix comprises a volume fraction of the PPTC body of 35% to 75%, wherein the conductive filler comprises a volume fraction of 25% to 65%, and wherein a volume resistivity of the conductive filler is less than 500 
     
     
         13 . The fuse device of  claim 10 , comprising a trip temperature of 120 C or less. 
     
     
         14 . The fuse device of  claim 10 , comprising a tungsten carbide filler. 
     
     
         15 . A fuse device, comprising:
 a PPTC body;   a first electrode, disposed on a first side of the PPTC body;   a second electrode, disposed on a second side of the PPTC body; and   wherein the PPTC body comprises a polymer matrix and a conductive filler,   wherein the polymer matrix comprises a linear low-density polyethylene material, having a melting temperature is a range of 100° C.   
     
     
         16 . The fuse device of  claim 15 , comprising a trip temperature of 90° C. 
     
     
         17 . The fuse device of  claim 15 , comprising a tungsten carbide filler.