Rechargeable battery circuit and structure for compatibility with a planar inductive charging platform

• US 7,495,414 B2
• Filed: 09/23/2005
• Issued: 02/24/2009
• Est. Priority Date: 07/25/2005
• Status: Active Grant

• Current Assignee: City University of Hong Kong
• Original Assignee: ConvenientPower HK Limited
• Inventors: Hui, Ron Shu-yuen
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): BOATENG, ALEXIS ASIEDUA
• Application Number:
  US11/234,045
• Publication Number:
  US 20070029965A1
• Time in Patent Office: 1,250 Days
• Field of Search: 320/108, 336/117
• US Class Current: 320/108
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery pack for an electronic device comprises battery cells, a battery charging circuit, and an energy receiving element adapted to receive power from a planar inductive charging system. The energy receiving element has an inductance and a capacitor is connected to the energy receiving element and forms a resonant tank therewith. A diode rectifier and a DC capacitor are connected to the energy receiving element to provide a rectified DC voltage that can be fed from the energy receiving element to said battery charging circuit. The energy receiving element may comprise a soft magnetic sheet with a coil wound around its edges, or a coil formed on a printed circuit board, or a combination of the two. The energy receiving element may be formed integrally with the battery pack, or may be provided as a separate component that can be added to an existing battery.

Claims

1. A battery pack for an electronic device comprising:

one or more battery cells, a battery charging circuit, an energy receiving element adapted to receive power from a planar inductive charging system, said energy receiving element having an inductance, a capacitor connected to said energy receiving element and forming a resonant tank therewith, and a diode rectifier and a DC capacitor connected to the energy receiving element to provide a rectified DC voltage that can be fed from the energy receiving element to said battery charging circuit, wherein said energy receiving element comprises a generally planar thin soft magnetic sheet and a first coil wound circumferentially around the edge of said sheet such that the coil lies in a plane defined by said magnetic sheet.

2. A battery pack as claimed in claim 1 wherein said capacitor is connected in series with said first coil and forms said resonant tank with said first coil and said magnetic sheet.

3. A battery pack as claimed in claim 1, further comprising a secondary energy receiving element comprising a second coil formed in a plane parallel to said soft magnetic sheet and wherein said second coil is connected in parallel with said first coil.

4. A battery pack as claimed in claim 3 wherein said second coil is formed on a printed circuit board.

5. A battery pack as claimed in claim 4 wherein said printed circuit board is fixed to said soft magnetic sheet.

6. A battery pack as claimed in claim 1 wherein said energy receiving element comprises a coil formed on a printed circuit board.

7. A battery pack as claimed in claim 1 wherein said diode rectifier is a voltage doubler.

8. A battery pack as claimed in claim 1 wherein said diode rectifier and said DC capacitor are formed as part of the battery charging circuit.

9. A battery pack as claimed in claim 1 further comprising a voltage regulator for regulating the output of the rectifier to the battery charging circuit.

10. An electronic device powered by a battery pack, said battery pack comprising one or more battery cells and a battery charging circuit, said device comprising a housing, means for connecting said battery charging circuit to an external power adaptor, and said device further comprising an energy receiving element adapted to receive power from a planar inductive charging system and for supplying power to said battery charging circuit, said energy receiving element having an inductance, and an capacitor connected to said energy receiving element and forming a resonant tank therewith, wherein said energy receiving element comprising a generally planar thin soft magnetic sheet located on a side of said battery pack facing a side of said housing adapted to be received on a said planar inductive charging system and a first coil wound circumferentially around the edge of said sheet such that the coil lies in a plane defined by said magnetic sheet.

11. An electronic device as claimed in claim 10 further comprising a secondary energy receiving element comprising a second coil formed in a plane parallel to said soft magnetic sheet and wherein said second coil is connected in parallel with said first coil.

12. An electronic device as claimed in claim 11 wherein said second coil is formed on a printed circuit board.

13. An electronic device as claimed in claim 12 wherein said printed circuit board is fixed to said soft magnetic sheet.

14. An electronic device as claimed in claim 10 wherein said capacitor is connected in series with said first coil and forms a resonant tank with said first coil and said magnetic sheet.

15. An electronic device as claimed in claim 10 wherein said energy receiving element comprises a coil formed on a printed circuit board.

16. An electronic device as claimed in claim 10 wherein said diode rectifier is a voltage doubler.

17. An electronic device as claimed in claim 10 wherein said diode rectifier and said DC capacitor are formed as part of the battery charging circuit.

18. An electronic device as claimed in claim 10 further comprising a voltage regulator for regulating the output of the rectifier to the battery charging circuit.

19. An energy receiving element adapted to be fixed to a battery pack to enable said battery pack to be charged from a planar inductive battery charging system, said energy receiving element comprising an AC capacitor, wherein said energy receiving element has an inductance and forms a resonant tank with the AC capacitor, and wherein said energy receiving element comprises a generally planar thin soft magnetic sheet and a first coil wound circumferentially around the edge of said sheet such that the coil lies in a plane defined by said magnetic sheet.

20. An energy receiving element as claimed in claim 19 further comprising a second coil formed as a spiral in a plane parallel to said soft magnetic sheet and wherein said second coil is connected in parallel with said first coil.

21. An energy receiving element as claimed in claim 20 wherein said second coil is formed on a printed circuit board.

22. An energy receiving element as claimed in claim 21 wherein said printed circuit board is fixed to said soft magnetic sheet.

23. An energy receiving element as claimed in claim 19 further comprising a diode rectifier and a DC capacitor to provide a rectified DC voltage that can be fed from the energy receiving element to a battery charging circuit of said battery pack.

24. An energy receiving element as claimed in claim 19 further comprising a voltage regulator for regulating the output of the rectifier to the battery charging circuit.

25. An energy receiving element as claimed in claim 19 comprising a coil formed on a printed circuit board.

26. An energy receiving element adapted to be fixed to a battery pack to enable said battery pack to be charged from a planar inductive battery charging system, said energy receiving element comprising a generally planar thin soft magnetic sheet and a first coil wound circumferentially around the edge of said sheet such that the coil lies in a plane defined by said magnetic sheet.

27. An energy receiving element as claimed in claim 26 further comprising a capacitor connected in series with said first coil and forming a resonant tank with said first coil and said magnetic sheet.

28. An energy receiving element as claimed in claim 26 further comprising a diode rectifier and a DC capacitor connected to the first coil to provide a rectified DC voltage that can be fed from the energy receiving element to a battery charging circuit of said battery pack.

29. An energy receiving element as claimed in claim 28 wherein said diode rectifier is a voltage doubler.

30. An energy receiving element as claimed in claim 26 further comprising a second coil formed as a spiral in a plane parallel to said soft magnetic sheet and wherein said second coil is connected in parallel with said first coil.

31. An energy receiving element as claimed in claim 30 wherein said second coil is formed on a printed circuit board.

32. An energy receiving element as claimed in claim 31 wherein said printed circuit board is fixed to said soft magnetic sheet.

33. An energy receiving element as claimed in claim 26 further comprising a voltage regulator for regulating the output of the rectifier to the battery charging circuit.