# US 12,406,782 B2 · Over-current protection device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,406,782 B2 - Document ID: US12406782B2 - Status: Granted - Kind: B2 - Application number: 18/150,729 - Filed: 2023-01-05 - Published: 2023-12-07 - Granted: 2025-09-02 - Earliest claimed: 2022-06-07 - Assignees: Polytronics Technology Corp. - Applicants: Polytronics Technology Corp. - Inventors: Chen-Nan Liu; Yung-Hsien Chang; Hsiu-Che Yen; Cheng-Yu Tung; Chia-Yuan Lee; Yu-Chieh Fu; Yao-Te Chang; Fu-Hua Chu - Web page: https://patentgrep.com/patent/US12406782B2 ## CPC - H01C 7/021: {formed with two or more layers} - H01C 1/1406: {Terminals or electrodes formed on resistive elements having positive temperature coefficient} - H01C 7/027: {consisting of conducting or semi-conducting material dispersed in a non-conductive organic material} - H01C 17/06586: {composed of organic material} - H01C: RESISTORS ## Abstract An over-current protection device comprises first and second electrode layers and a PTC material layer laminated therebetween. The PTC material layer includes a polymer matrix, a conductive filler and a titanium-containing inner filler. The polymer matrix has a fluorine-free polyolefin-based polymer. The titanium-containing inner filler has a compound represented by a general formula of MTiO3, wherein the M represents transition metal or alkaline earth metal. The total volume of the PTC material layer is calculated as 100%, and the titanium-containing inner filler accounts for 1-9% by volume of the PTC material layer. ## Claims ### Claim 1 An over-current protection device, comprising: a first electrode layer; a second electrode layer; and a positive temperature coefficient (PTC) material layer laminated between the first electrode layer and the second electrode layer, the PTC material layer comprising: a polymer matrix comprising a fluorine-free polyolefin-based polymer and a fluoropolymer, wherein the total volume of the PTC material layer is calculated as 100%, and the fluorine-free polyolefin-based polymer accounts for 41-55% and the fluoropolymer accounts for 5-7% by volume of the PTC material layer; a conductive filler dispersed in the polymer matrix, thereby forming an electrically conductive path in the PTC material layer; and a titanium-containing inner filler dispersed in the polymer matrix, wherein the titanium-containing inner filler has a compound represented by a general formula (I): MTiO3 (I) wherein the M represents transition metal or alkaline earth metal, and the total volume of the PTC material layer is calculated as 100%, and the titanium-containing inner filler accounts for 1-9% by volume of the PTC material layer. ### Claim 2 (depends on 1) The over-current protection device of claim 1, wherein the fluorine-free polyolefin-based polymer is selected from the group consisting of high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), polyvinyl wax, vinyl polymer, polypropylene, polybutene, polyvinyl chlorine, and mixture or copolymer of combinations thereof. ### Claim 3 (depends on 2) The over-current protection device of claim 2, wherein the titanium-containing inner filler is selected from the group consisting of BaTiO3, SrTiO3, CaTiO3, and any combination thereof. ### Claim 4 (depends on 3) The over-current protection device of claim 3, wherein BaTiO3 accounts for 1-9% by volume of the PTC material layer. ### Claim 5 (depends on 3) The over-current protection device of claim 3, wherein SrTiO3 accounts for 1-3% by volume of the PTC material layer. ### Claim 6 (depends on 3) The over-current protection device of claim 3, wherein CaTiO3 accounts for 1-3% by volume of the PTC material layer. ### Claim 7 (depends on 3) The over-current protection device of claim 3, wherein the titanium-containing inner filler has a median diameter ranging from 5 μm to 10 μm. ### Claim 8 (depends on 3) The over-current protection device of claim 3, wherein the conductive filler comprises a conductive ceramic filler and carbon black, and the conductive ceramic filler is selected from the group consisting of tungsten carbide, titanium carbide, vanadium carbide, zirconium carbide, niobium carbide, tantalum carbide, molybdenum carbide, hafnium carbide, titanium boride, vanadium boride, zirconium boride, niobium boride, molybdenum boride, hafnium boride, zirconium nitride, and any combination thereof. ### Claim 9 (depends on 1) The over-current protection device of claim 1, wherein the fluoropolymer has a first dielectric constant and the titanium-containing inner filler has a second dielectric constant, and a value obtained by dividing the second dielectric constant by the first dielectric constant is in a range from 16 to 667. ### Claim 10 (depends on 9) The over-current protection device of claim 9, wherein the fluoropolymer is selected from the group consisting of polyvinylidene fluoride, poly (tetrafluoroethylene), poly (vinylidene fluoride), ethylene-tetra-fluoro-ethylene, tetrafluoroethylene-hexafluoro-propylene copolymer, ethylene-tetrafluoroethylene copolymer, perfluoroalkoxy modified tetrafluoroethylenes, poly (chlorotri-fluorotetrafluoroethylene), vinylidene fluoride-tetrafluoroethylene copolymer, tetrafluoroethylene-perfluorodioxole copolymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, and any combination thereof. ### Claim 11 (depends on 10) The over-current protection device of claim 10, wherein the conductive filler comprises a conductive ceramic filler and carbon black, and the conductive ceramic filler is selected from the group consisting of tungsten carbide, titanium carbide, vanadium carbide, zirconium carbide, niobium carbide, tantalum carbide, molybdenum carbide, hafnium carbide, titanium boride, vanadium boride, zirconium boride, niobium boride, molybdenum boride, hafnium boride, zirconium nitride, and any combination thereof. ### Claim 12 (depends on 1) The over-current protection device of claim 1, wherein the over-current protection device has an electrical resistivity ranging from 0.0217 Ω·cm to 0.0287 Ω·cm. ### Claim 13 (depends on 12) The over-current protection device of claim 12, wherein the over-current protection device has a trip threshold value making the over-current protection device change from an electrically conductive state to an electrically non-conductive state, and the trip threshold value ranges from 0.198 A/mm2 to 0.247 A/mm2. ### Claim 14 (depends on 13) The over-current protection device of claim 13, wherein the PTC material layer has a top-view area ranging from 25 mm2 to 72 mm2.