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US 10,878,980 B2Granted
PPTC material with low percolation threshold for conductive filler
AssigneeLittelfuse, Inc.
InventorsJianhua Chen, Chun Kwan Tsang
Life of this patent
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Abstract
A polymeric positive temperature coefficient (PPTC) device including 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 is formed of a PPTC material that includes a polymer matrix and a conductive filler, wherein the conductive filler defines 20%-39% by volume of the PPTC material.
Claims8
A polymeric positive temperature coefficient (PPTC) 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 is formed of a PPTC material that includes a polymer matrix and a conductive filler comprising tungsten carbide, the conductive filler further comprising a volume fraction parameter and a median diameter of conductive particles parameter such that PPTC material exhibits a resistivity of approximately 0.15 ohm-cm;
- wherein the volume fraction parameter and median diameter of conductive particles parameter are selected from a group consisting of:
- 27% volume fraction of conductive particles with a median diameter of 0.55 μm;
- 37% volume fraction of conductive particles with a median diameter of 1.0 μm;
- 39% volume fraction of conductive particles with a median diameter of 1.57 μm;
- 41.2% volume fraction of conductive particles with a median diameter of 2.15 μm;
- 42.5% volume fraction of conductive particles with a median diameter of 3.21 μm;
- and
- 45.5% volume fraction of conductive particles with a median diameter of 4.82 μm.
10 more elements
A polymeric positive temperature coefficient (PPTC) material comprising:
- a polymer matrix;
- and
- a conductive filler comprising tungsten carbide, the conductive filler further comprising a volume fraction parameter and a median diameter of conductive particles parameter such that PPTC material exhibits a resistivity of approximately 0.15 ohm-cm;
- wherein the volume fraction parameter and median diameter of conductive particles parameter are selected from a group consisting of:
- 27% volume fraction of conductive particles with a median diameter of 0.55 μm;
- 37% volume fraction of conductive particles with a median diameter of 1.0 μm;
- 39% volume fraction of conductive particles with a median diameter of 1.57 μm;
- 41.2% volume fraction of conductive particles with a median diameter of 2.15 μm;
- 42.5% volume fraction of conductive particles with a median diameter of 3.21 μm;
- and
- 45.5% volume fraction of conductive particles with a median diameter of 4.82 μm.
8 more elements
Dependencies are inferred from the claim text.