Low resistance, high voltage and resistance stable PPTC material and manufacturing
AssigneeLittelfuse, Inc.
InventorsZhiyong Zhou, Jianhua Chen, Wei Zheng
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Abstract
A novel polymer positive temperature coefficient (PPTC) material, device, and method of fabrication. The PPTC device may include a PPTC body; a first electrode disposed on a first surface of the PPTC body and a second electrode disposed on a second surface of the PPTC body, opposite the first electrode. The PPTC body may include a polymer matrix; and a conductive filler, disposed in the polymer matrix. The conductive filler may include a tungsten carbide component comprising at least 30 volume percent of the PPTC body; and a carbon component, wherein a total volume fraction of the conductive filler comprises between forty volume percent and sixty five volume percent of the PPTC body.
Claims12
A polymer positive temperature coefficient (PPTC) device, comprising:
- a PPTC body;
- and
- a first electrode disposed on a first surface of the PPTC body and a second electrode disposed on a second surface of the PPTC body, opposite the first electrode,
- the PPTC body comprising:
- a polymer matrix;
- and
- a conductive filler, disposed in the polymer matrix,
- wherein the conductive filler comprises:
- a tungsten carbide component;
- and
- a carbon component,
- wherein the tungsten carbide component comprises between thirty volume percent and forty five volume percent of the PPTC body and has a primary particle size of 0.5 μm to 5 μm,
- wherein the carbon component comprises between five volume percent and twenty volume percent of the PPTC body and has a primary particle size of 10 nm to 100 nm, and
- wherein a total volume fraction of the conductive filler comprises between forty volume percent and sixty five volume percent of the PPTC body.
A composition for forming a polymer positive temperature coefficient (PPTC) body in a PPTC device, comprising:
- a polymer matrix;
- and
- a conductive filler, disposed in the polymer matrix,
- wherein the conductive filler comprises:
- a tungsten carbide component;
- and
- a carbon component,
- wherein the tungsten carbide component comprises between thirty volume percent and forty five volume percent of the PPTC body and has a primary particle size of 0.5 μm to 5 μm,
- wherein the carbon component comprises between five volume percent and twenty volume percent of the PPTC body and has a primary particle size of 10 nm to 100 nm, and
- wherein a total volume fraction of the conductive filler comprises between forty volume percent and sixty five volume percent of the PPTC body.
A method of forming a polymer positive temperature coefficient (PPTC) body for a PPTC device, comprising:
- providing a polymer matrix;
- and
- adding a conductive filler to the polymer matrix,
- wherein the conductive filler comprises:
- a tungsten carbide component;
- and
- a carbon component,
- wherein the tungsten carbide component comprises between thirty volume percent and forty five volume percent of the PPTC body and has a primary particle size of 0.5 μm to 5 μm,
- wherein the carbon component comprises between five volume percent and twenty volume percent of the PPTC body and has a primary particle size of 10 nm to 100 nm, and
- wherein a total volume fraction of the conductive filler comprises between forty volume percent and sixty five volume percent of the PPTC body.
Dependencies are inferred from the claim text.