Protection Element

• US 20160099458A1
• Filed: 08/30/2013
• Published: 04/07/2016
• Est. Priority Date: 08/31/2012
• Status: Active Grant

• Current Assignee: Littelfuse Japan G.K. (Littelfuse Incorporated)
• Original Assignee: Tyco Electronics Japan GK (TE Connectivity Limited)
• Inventors: Tanaka, Arata, Usui, Hisashi, Nomura, Keiichiro
• Granted Patent: US 10,090,509 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01C 7/02 having positive temperature coefficient ceramics C04B
• CPC Class Codes: H01C 7/021 formed as one or more layers or coatings
• CPC Class Codes: H01H 2085/025 Structural association with a binding post of a storage battery
• CPC Class Codes: H01H 85/08 characterised by the shape or form of the fusible member
• CPC Class Codes: H01H 85/11 with applied local area of a metal which, on melting, forms a eutectic with the main material of the fusible member, i.e. M-effect devices
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 2200/106 PTC
• CPC Class Codes: H01M 50/574 Devices or arrangements for the interruption of current
• CPC Class Codes: H01M 50/581 in response to temperature
• CPC Class Codes: H01M 50/583 in response to current, e.g. fuses
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention provides a protection device which includes: a PTC laminar element which is formed of an insulation resin and has at least one throughhole; electrically conductive metal thin layers which are positioned on each of main surfaces of the laminar element, and a fuse layer which is positioned on a side surface defining at least one of said at least one throughhole and electrically connects the electrically conductive metal thin layers which are positioned on each of main surfaces of the laminar element. The protection device of the present invention allows a larger amount of a current to flow therethrough and can provide a protection from an excessive current.

Claims

1. A protection device which comprises

a PTC laminar element which is formed of a PTC composition and has at least one throughhole,

an electrically conductive metal thin layer which is positioned on each of main surfaces of the PTC laminar element, and

a fuse layer which is positioned on a side surface defining at least one of said at least one throughhole and electrically connects the electrically conductive metal thin layers each of which is positioned on each of the main surfaces.

2. The protection device according to claim 1, characterized in that the fuse layer comprises at least a first metal layer consisting of a metal having a higher melting point and a second metal layer consisting of a metal having a lower melting point.

3. The protection device according to claim 1, characterized in that the fuse layer consists of the first metal layer consisting of the metal having the higher melting point and the second metal layer consisting of the metal having the lower melting point.

4. The protection device according to claim 2, characterized in that the metal having the higher melting point is Ni.

5. The protection device according to claim 2, characterized in that the metal having the lower melting point has a melting point lower than a decomposition temperature of a polymer material of the PTC composition.

6. The protection device according to claim 5, characterized in that the metal having the lower melting point is Sn, an Sn—

Cu alloy or an Sn—

Bi alloy.

7. The protection device according to claim 2, characterized in that the first metal layer is formed by electroless plating with the metal having the higher melting point and the second metal layer is formed by electrolytic plating with the metal having the lower melting point on the first metal layer.

8. The protection device according to claim 2, characterized in that a thickness ratio between the first metal layer and the second metal layer is 1:

100-5;

1.

9. The protection device according to claim 2, characterized in that the electrically conductive metal thin layer and the fuse layers are formed to be integral by plating with the metal having the higher melting point and the metal having the lower melting point.

10. The protection device according to claim 1, characterized by further comprising a metal foil which is positioned between the PTC laminar element and the electrically conductive metal thin layer.

11. The protection device according to claim 10, characterized in that the metal foil is a nickel foil.

12. The protection device according to claim 1, characterized in that the PTC laminar element is an annular element which is defined by an inner periphery surface and an outer periphery surface, and has one throughhole which is defined by the inner periphery surface.

13. The protection device according to claim 1, characterized in that the PTC laminar element is an annular element which is defined by an inner periphery surface and an outer periphery surface, and has at least two throughholes which comprises one central throughhole which is defined by the inner periphery surface and at least one surrounding throughhole which is positioned between the inner periphery surface and the outer periphery surface, and the surrounding throughhole has the fuse layer.

14. The protection device according to claim 13, characterized in that eight of the surrounding throughholes are provided through the PTC laminar element around the central throughhole at an equal angle interval of 45°

.

15. The protection device according to claim 1, characterized in that the laminar element is in the form of a circular ring.

16. An electrical apparatus characterized by comprising the protection device according to claim 1.

17. The electrical apparatus according to claim 16 which is a secondary battery cell.

19. The electrical apparatus according to claim 16 characterized in that the fuse layer comprises at least a first metal layer consisting of a metal having a higher melting point and a second metal layer consisting of a metal having a lower melting point.

20. The electrical apparatus according to claim 16 characterized in that the fuse layer consists of the first metal layer consisting of the metal having the higher melting point and the second metal layer consisting of the metal having the lower melting point

18. A washer which comprises

a PTC laminar element which is formed of a PTC composition and has at least one throughhole,

an electrically conductive metal thin layer which is positioned on each of main surfaces of the PTC laminar element, and

a fuse layer comprising which is positioned on a side surface defining at least one of said at least one throughhole and electrically connects the electrically conductive metal thin layers each of which is positioned on each of the main surfaces.