Induction charging system

• US 9,479,007 B1
• Filed: 02/21/2014
• Issued: 10/25/2016
• Est. Priority Date: 02/21/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Jol, Eric S., Kamei, Ibuki, Jones, Warren Z.
• Primary Examiner(s): Kik, Phallaka
• Application Number:
  US14/187,193
• Time in Patent Office: 977 Days
• Field of Search: 320/108, 336/94, 336/92
• US Class Current: 1/1
• CPC Class Codes: H01F 1/44 of magnetic liquids, e.g. ferrofluids particles in a bonding agent H01F1/28, H01F1/36, H01F1/37
• CPC Class Codes: H01F 27/02 Casings
• CPC Class Codes: H01F 3/08 made from powder powder coatings on sheets H01F3/02; on strips or ribbons H01F3/04; on wires H01F3/06
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction

Abstract

An inductive charging system and method is disclosed. A ferrofluid layer is disposed between the charging coil and the receiving coil. The ferrofluid layer directs and focuses the magnetic flux field flowing between the charging coil and the receiving coil.

Claims

1. An inductive charging device comprising:

a housing defining an upper surface;

an electromagnetic transceiver coil in the housing; and

a ferrofluid layer in the housing between the coil and the upper surface,

and operative to shape an electromagnetic field between the transceiver coil and a receiving coil abutting the upper surface.

2. The inductive charging device of claim 1 wherein said ferrofluid layer includes ferromagnetic particles suspended in one of water, an organic solvent or silicone gel.

3. The inductive charging device of claim 1 wherein said ferrofluid layer is contained in a rigid enclosure.

4. The inductive charging device of claim 1 wherein said ferrofluid layer is contained in a segmented enclosure.

5. The inductive charging device of claim 1, wherein said ferrofluid changes location when a magnetic field is created by said electromagnetic housing.

6. The inductive charging device of claim 5, wherein said ferrofluid layer is operative to direct said magnetic field in a path other than a default path of the field assumed in the absence of the ferrofluid.

7. An inductive charging system comprising:

an electronic device including;

a rechargeable battery;

a receiving coil electromagnetically associated with said battery;

an inductive charging device including;

a housing having an upper surface;

a transceiver coil in said housing;

a ferrofluid layer positioned between said transceiver coil and said receiving coil; and

whereby said ferrofluid layer directs an electromagnetic field between said receiving coil and said transceiver coil when said electronic device is positioned adjacent said upper surface.

8. The inductive charging system of claim 7 wherein said ferrofluid layer is located in said charging device between said transceiver coil and said upper surface.

9. The inductive charging system of claim 7 wherein said ferrofluid layer is located in said electronic device such that said ferrofluid layer is positioned between said receiving coil and said transceiver coil when said electronic device is positioned adjacent said upper surface.

10. The inductive charging system of claim 7 further including:

a first magnet located in said electronic device adjacent to said receiving coil; and

a second magnet located in said inductive charging device adjacent to said transceiver coil.

11. The inductive charging system of claim 7 wherein said ferrofluid layer includes ferromagnetic particles in a suspension.

12. The inductive charging system of claim 7, wherein:

said ferrofluid layer is contained within an enclosure; and

said ferrofluid layer moves within said enclosure when a magnetic field is generated by said transceiver coil.

13. The inductive charging system of claim 7, wherein said ferrofluid layer enhances a voltage inductively transmitted by said transceiver coil to said receiving coil.

14. The inductive charging system of claim 13, wherein said ferrofluid layer defines at least a portion of a path of magnetic flux between said transceiver coil and said receiving coil.

15. The inductive charging system of claim 14, wherein said ferrofluid layer reduces a charging time for said inductive charging device.

16. A method for charging an electronic device comprising the steps of:

providing an inductive charging device;

placing an rechargeable battery on the inductive charging device;

generating a magnetic flux field between the charging device and the rechargeable battery; and

directing said magnetic flux field with a ferrofluid layer positioned between the charging device and the rechargeable battery.

17. The method of claim 16 wherein said rechargeable battery is contained in an electronic device.

18. The method of claim 17 wherein said ferrofluid layer is located adjacent said rechargeable battery in said electronic device.

19. The method of claim 16 wherein said ferrofluid layer is located in said inductive charging device.

20. The method of claim 16 wherein said ferrofluid layer includes ferromagnetic particles in water.