Over-current protection device

Patent metadata

Field	Value
Publication number	US-10056176-B2
Application number	US-201615156813-A
Country	US
Kind code	B2
Filing date	May 17, 2016
Priority date	Jul 16, 2015
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

An over-current protection device comprises a PTC device and a heating element operable to heat the PTC device. The PTC device contains crystalline polymer and metal or ceramic conductive filler dispersed therein. The PTC device has a resistivity less than 0.1 Ω·cm. The over-current protection device has the relation: It (heating)<Ih (60° C.)×10%, where Ih (60° C.) is a hold current of the over-current protection device at 60° C. when the heating element is not activated; It (heating) is a trip current of the over-current protection device when the heating element is activated to heat the PTC device. The PTC device has high hold current, thereby allowing a battery containing the device can be fast charged with a large current. In a specific situation, the heating element heats the PTC device to decrease the hold current of the over-current protection device of low resistivity, and accordingly the PTC device can trip by a small current.

First claim

What is claimed is:

1. An over-current protection device, comprising:
at least one PTC device comprising crystalline polymer and metal or conductive ceramic filler dispersed therein, the PTC device having a resistivity less than 0.1 Ω·cm; and
at least one heating element operable to heat the PTC device;
wherein two ends of the PTC device electrically connect to a first electrode and a second electrode, two ends of the heating element electrically connect to the second electrode and a third electrode, and the first, second and third electrodes are formed at a lower surface of the over-current protection device as interfaces for surface-mounting, and
wherein the over-current protection device has the relation: It (heating)<Ih (60° C.)×10%, where Ih (60° C.) is a hold current of the over-current protection device at 60° C. when the heating element is not activated; It (heating) is a trip current of the over-current protection device when the heating element is activated to heat the PTC device.

2. The over-current protection device of claim 1 , wherein the heating element heats the PTC device to decrease the hold current of the PTC device to induce a trip of the PTC device.

3. The over-current protection device of claim 1 , wherein the heating element has a resistance sufficient to induce a trip within 60 seconds at ambient temperature of 80° C. when a current of 8 A is applied to the PTC device.

4. The over-current protection device of claim 1 , wherein the heating element has a resistance larger than or equal to 0.1Ω.

5. The over-current protection device of claim 1 , wherein the heating element comprises two resistors in serial connection.

6. The over-current protection device of claim 1 , wherein the crystalline polymer has a melting point larger than 150° C.

7. The over-current protection device of claim 1 , wherein the heating element is a ceramic PTC heater, a polymeric PTC heater or a resistor-type heater.

8. The over-current protection device of claim 7 , wherein the polymeric PTC heater comprises crystalline polymer of a melting point greater than 150° C.

9. The over-current protection device of claim 7 , wherein the polymeric PTC heater comprises carbon black as conductive filler.

10. The over-current protection device of claim 1 , wherein the heating element is disposed between two PTC devices, and the two PTC devices are in parallel connection.

11. The over-current protection device of claim 1 , wherein the PTC device comprises a PTC material layer, a first metal foil and a second metal foil, the first metal foil is formed on an upper surface of the PTC material layer, the second metal foil is formed on a lower surface of the PTC material layer, the heating element comprises a heating layer, a first conductive layer and a second conductive layer, the first conductive layer is formed on an upper surface of the heating layer, and the second conductive layer is formed on a lower surface of the heating layer.

12. The over-current protection device of claim 11 , wherein the first electrode electrically connects to the first metal foil, the second electrode electrically connects to the second metal foil and the first conductive layer, and the third electrode electrically connects to the second conductive layer.

13. The over-current protection device of claim 12 , further comprising:
a first conductive connecting member extending vertically to connect to the first electrode and the first metal foil;
a second conductive connecting member extending vertically to connect to the second electrode, the second metal foil and the first conductive layer; and
at least one conductive hole extending vertically to connect to the third electrode and the second conductive layer;
wherein the first and second conductive layers are separated from the first conductive connecting member.

14. An over-current protection device, comprising:
at least one PTC device comprising crystalline polymer and metal or conductive ceramic filler dispersed therein, the PTC device having a resistivity less than 0.1 Ω·cm;
at least one heating element operable to heat the PTC device; and
a first electrode, a second electrode, a third electrode and a fourth electrode formed at a lower surface of the over-current protection device as interfaces for surface-mounting,
wherein the PTC device comprises a PTC material layer, a first metal foil and a second metal foil, the first metal foil is formed on an upper surface of the PTC material layer, the second metal foil is formed on a lower surface of the PTC material layer, the heating element comprises a heating layer, a first conductive layer and a second conductive layer, the first conductive layer is formed on an upper surface of the heating layer, and the second conductive layer is formed on a lower surface of the heating layer,
wherein the first electrode electrically connects to the first metal foil, the second electrode electrically connects to the second metal foil, the third electrode electrically connects to the first conductive layer, and the fourth electrode electrically connects to the second conductive layer, and
wherein the over-current protection device has the relation: It (heating)<Ih (60° C.)×10%, where Ih (60° C.) is a hold current of the over-current protection device at 60° C. when the heating element is not activated; It (heating) is a trip current of the over-current protection device when the heating element is activated to heat the PTC device.

15. The over-current protection device of claim 14 , further comprising:
a first conductive connecting member extending vertically to connect to the first electrode and the first metal foil;
a second conductive connecting member extending vertically to connect to the second electrode and the second metal foil;
a third conductive connecting member extending vertically to connect to the third electrode and the first conductive layer; and
a fourth conductive connecting member extending vertically to connect to the fourth electrode and the second conductive layer;
wherein the first and second conductive layers are separated from the first and second conductive connecting members.

16. An over-current protection device, comprising:
at least one PTC device comprising crystalline polymer and metal or conductive ceramic filler dispersed therein, the PTC device having a resistivity less than 0.1 Ω·cm;
at least one heating element operable to heat the PTC device; and
a first electrode, a second electrode, a third electrode and a fourth electrode formed at a lower surface of the over-current protection device as interfaces for surface-mounting,
wherein the PTC device comprises a PTC material layer, a first metal foil and a second metal foil, the first metal foil is formed on an upper surface of the PTC material layer, the second metal foil is formed on a lower surface of the PTC material layer, the heating element comprises a heating layer, a first conductive layer, a second conductive layer and a third conductive layer, the first conductive layer is formed on an upper surface of the heating layer, and the second and third conductive layers are formed on a lower surface of the heating layer,
wherein the first electrode electrically connects to the first metal foil, the second electrode electrically connects to the second metal foil, the third electrode electrically connects to the second conductive layer, and the fourth electrode electrically connects to the third conductive layer, and
wherein the over-current protection device has the relation: It (heating)<Ih (60° C.)×10%, where Ih (60° C.) is a hold current of the o

Assignees

• Polytronics Technology Corp

Inventors

• Wang David Shau Chew
• Tseng Chun Teng
• Su Tsungmin
• Chang Yao Te

Classifications

• H01C7/021 Primary

  formed with two or more layers · CPC title

• H01C7/027 Primary

  consisting of conducting or semi-conducting material dispersed in a non-conductive organic material · CPC title