Electrical devices and methods of charging

• US 8,836,278 B2
• Filed: 12/05/2006
• Issued: 09/16/2014
• Est. Priority Date: 12/05/2005
• Status: Active Grant

• Current Assignee: City University of Hong Kong
• Original Assignee: City University of Hong Kong
• Inventors: Wong, Hon Yee
• Primary Examiner(s): Tso, Edward
• Assistant Examiner(s): TORRES RUIZ, JOHALI ALEJANDRA
• Application Number:
  US11/566,864
• Publication Number:
  US 20070127184A1
• Time in Patent Office: 2,842 Days
• Field of Search: 320/108
• US Class Current: 320/108
• 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

Abstract

An electrical device of the type having a rechargeable battery and which has a body having at least a portion formed with a circumference extending about an axis, is provided with a secondary winding adapted to receive magnetic flux from a planar charging surface that is arranged around the circumference in a plane perpendicular to the axis. Such a device may be charged by placing the device on a planar charging surface such that the body portion contacts the planar charging surface with the axis perpendicular to the charging surface and the secondary winding parallel to the charging surface.

Claims

1. An electrical device, comprising:

a body having a portion formed with a circumference extending about an axis;

a rechargeable battery housed within the body;

a first connection circuit in connection with the rechargeable battery disposed within the body; and

a removable cap adapted to fit over and at least partly surround the body portion, the cap including;

an integrally formed secondary winding surrounding the body portion about the axis, the secondary winding being adapted to receive magnetic flux extending from a planar charging surface;

a layer of magnetic material disposed between the secondary winding and the body portion for reducing current induced in the body of the electrical device; and

a second connection circuit for connecting the secondary winding to the first connection circuit so as to charge the rechargeable battery in the body;

wherein the cap is arranged to be in contact with the planar charging surface and to support the electrical device on the planar charging surface during charging of the electrical device; and

wherein the secondary winding is arranged to be substantially parallel to the planar charging surface so that lines of magnetic flux extending from the planar charging surface pass substantially perpendicularly through the secondary winding during charging of the electrical device.

2. An electrical device in accordance with claim 1, wherein the body portion and the secondary winding each have a generally circular cross section.

3. An electrical device in accordance with claim 1, wherein an array of primary coils that generate the lines of magnetic flux that extend generally perpendicular to the planar charging surface is disposed beneath the planar charging surface.

4. A cap for an electrical device, wherein the cap is removably fitted over and at least partly surrounding a body portion of an electrical device, the cap comprising:

an integrally formed secondary winding surrounding the body portion, the secondary winding being adapted to receive magnetic flux extending from a planar charging surface;

a layer of magnetic material disposed between the secondary winding and the body portion of the electrical device for reducing current induced in the body of the electrical device; and

a connection circuit for connecting the secondary winding to the electrical device so as to charge a rechargeable battery in the electrical device;

wherein the cap is arranged to be in contact with the planar charging surface and to support the electrical device on the planar charging surface during charging of the electrical device; and

wherein the secondary winding is arranged to be substantially parallel to the planar charging surface so that lines of magnetic flux extending from the planar charging surface pass substantially perpendicularly through the secondary winding during charging of the electrical device.

5. An electrical device in accordance with claim 4, wherein the body portion of the electrical device and the secondary winding each have a generally circular cross section.

6. An electrical device in accordance with claim 4, wherein an array of primary coils that generate the lines of magnetic flux that extend generally perpendicular to the planar charging surface that is disposed beneath the planar charging surface.

7. An apparatus, comprising:

a cap for an electrical device, wherein the cap is adapted to be removably fitted over and at least partly surround a body portion of an electrical device, the cap comprising;

an integrally formed secondary winding to surround the body portion when present, the secondary winding being adapted to receive magnetic flux extending from a planar charging surface when present; and

a layer of magnetic material situated such that when the cap is removably fitted over the body portion, the layer of magnetic material is disposed between the secondary winding and the body portion of the electrical device for reducing current induced in the body of the electrical device;

wherein the cap is configured for placing in contact with the planar charging surface when present and to support the electrical device on the planar charging surface during charging of the electrical device; and

wherein the secondary winding is arranged to be substantially parallel to the planar charging surface when present so that lines of magnetic flux extending from the planar charging surface pass substantially perpendicularly through the secondary winding during charging of the electrical device.

8. An apparatus in accordance with claim 7, wherein the secondary winding has a generally circular cross section.

9. An apparatus in accordance with claim 8, further comprising a body portion of an electrical device usable with the cap, the body portion having a generally circular cross section.

10. An apparatus in accordance with claim 7, further comprising a connection circuit for connecting the secondary winding to the electrical device when present so as to charge a rechargeable battery in the electrical device.

11. An apparatus in accordance with claim 7, further comprising a planar charging surface having an array of primary coils disposed beneath the planar charging surface that generate the lines of magnetic flux that extend generally perpendicular to the planar charging surface.