Contactless electricity supply device with foreign object detector

• US 9,553,636 B2
• Filed: 05/23/2012
• Issued: 01/24/2017
• Est. Priority Date: 05/27/2011
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Maikawa, Kengo, Imazu, Tomoya
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): WARMFLASH, MICHAEL J
• Application Number:
  US13/822,260
• Publication Number:
  US 20130169062A1
• Time in Patent Office: 1,707 Days
• Field of Search: 307 1-104
• US Class Current: 1/1
• CPC Class Codes: B60L 53/124 Detection or removal of foreign bodies
• CPC Class Codes: B60L 53/126 Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver
• CPC Class Codes: B60M 7/00 Power lines or rails specially adapted for electrically-propelled vehicles of special types, e.g. suspension tramway, ropeway, underground railway
• CPC Class Codes: H01F 27/363 made of electrically conductive material
• 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 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H04B 5/263 Multiple coils at either side
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

This contactless electricity supply device, which contactlessly performs charging of the battery (28) of a vehicle, is provided with: an electricity transmission coil (12) disposed at a road surface; and an electricity reception coil (22) disposed in the vehicle. A foreign object detection coil (13) is provided to the upper surface of the electricity transmission coil (12), and on the basis of induced voltage arising at the foreign object detection coil (13) during a trial electricity supply, foreign objects between the electricity transmission coil (12) and the electricity reception coil (22) are detected.

Claims

1. A contactless electricity supply device comprising:

a second coil that sends electricity to a first coil contactlessly at least through magnetic coupling therebetween;

a third coil provided at a first side of the second coil, wherein the first side faces the first coil; and

a foreign object detector that detects a foreign object between the first coil and the second coil on a basis of a change of an induced voltage occurring in the third coil, wherein the change of the induced voltage results from a change of magnetic flux between the first coil and the second coil,

wherein the third coil includes a plurality of coils,

wherein the third coil is arranged parallel to the first side of the second coil facing the first coil, and

wherein each of the plurality of coils of the third coil is sector-shaped, and arranged to extend radially from a central point of the second coil.

2. The contactless electricity supply device as claimed in claim 1, wherein at least two coils of the third coil that are adjacent to each other are arranged so that a direction of induced current flowing through one of the at least two coils is opposite to a direction of induced current flowing through another of the at least two coils when the foreign object is absent.

3. The contactless electricity supply device as claimed in claim 2, wherein the at least two coils have coil areas equal to each other.

4. The contactless electricity supply device as claimed in claim 3, wherein the foreign object detector determines that the foreign object is present, in response to a condition that the induced voltage of the third coil is nonzero.

5. The contactless electricity supply device as claimed in claim 1, wherein the plurality of coils of the third coil are connected to each other by a single wire.

6. The contactless electricity supply device as claimed in claim 1, wherein:

the foreign object detector determines whether or not the foreign object is present, by comparing the induced voltage of the third coil with a voltage threshold value for determination; and

the voltage threshold value for determination is set higher than the induced voltage of the third coil when no foreign object is present.

7. The contactless electricity supply device as claimed in claim 1, wherein:

the plurality of coils of the third coil are independent from each other; and

the foreign object detector locates the foreign object on a basis of induced voltages of the individual coils.

8. The contactless electricity supply device as claimed in claim 1, wherein:

a trial electricity supply is performed prior to a normal electricity supply; and

foreign object detection is performed during the trial electricity supply.

9. The contactless electricity supply device as claimed in claim 1, wherein:

a magnetic member is provided at a second side of the second coil, the second side being opposite to the first side of the second coil; and

the magnetic member is parted from the third coil with a distance therebetween.

10. The contactless electricity supply device as claimed in claim 9, wherein the magnetic member is a ferrite core.

11. The contactless electricity supply device as claimed in claim 1, wherein:

a magnetic member is provided at a second side of the second coil, the second side being opposite to the first side of the second coil; and

the magnetic member has a substantially flat surface facing the second coil.

12. The contactless electricity supply device as claimed in claim 11, wherein the magnetic member is a ferrite core.

13. A contactless electricity supply device comprising:

a power feeding coil that sends electricity to a power receiving coil contactlessly at least through magnetic coupling therebetween;

a foreign object detection coil provided at a first side of the power feeding coil, wherein the first side faces the power receiving coil; and

a control section that detects a foreign object between the power feeding coil and the power receiving coil on a basis of a change of an induced voltage occurring in the foreign object detection coil, wherein the change of the induced voltage results from a change of magnetic flux between the power feeding coil and the power receiving coil,

wherein the foreign object detection coil includes a plurality of coils,

wherein the foreign object detection coil is arranged parallel to the first side of the power feeding coil facing the power receiving coil, and

wherein each of the plurality of coils of the foreign object detection coil is sector-shaped, and arranged to extend radially from a central point of the power feeding coil.