Over-current protection device
US9431822B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 11, 2015 |
| Grant date | Aug 30, 2016 |
| Priority date | — |
| Expiry date | Mar 12, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01C17/06586
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An over-current protection device includes two metal foils and a PTC material layer laminated therebetween. The PTC material layer has a volumetric resistivity between about 0.07 Ω-cm and 0.45 Ω-cm. The PTC material layer comprises a crystalline polymer and first and second conductive fillers dispersed therein. The first conductive filler is carbon black powder. The second conductive filler is selected from the group consisting of metal powder and conductive ceramic powder and has a volumetric resistivity less than 0.1 Ω-cm. The weight ratio of the second conductive filler to the first conductive filler is less than 4. The resistance jump R300/Ri of the over-current protection device is in the range from 1.5 to 5, where Ri is an initial resistance and R300 is a resistance after tripping 300 times.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.