Temperature management for inductive charging systems

• US 10,320,230 B2
• Filed: 03/25/2015
• Issued: 06/11/2019
• Est. Priority Date: 03/26/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Golko, Albert J., Jol, Eric S., Graham, Christopher S., Thompson, Paul J., Alves, Jeffrey M., Yao, Stephen E., Brzezinski, Makiko K., Moyer, Todd K., Wagman, Daniel, Lewis-Kraus, Micah
• Primary Examiner(s): Isla, Richard
• Assistant Examiner(s): Torres Ruiz, Johali A
• Application Number:
  US14/668,551
• Publication Number:
  US 20150280483A1
• Time in Patent Office: 1,539 Days
• Field of Search: 320108
• CPC Class Codes: H01F 27/025 Constructional details relating to cooling
• CPC Class Codes: H01F 27/22 Cooling by heat conduction through solid or powdered fillings
• 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 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 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction

Abstract

A thermal management system for an electromagnetic induction-power transfer system. The system may include a charging apparatus including a housing that defines an interface surface. An accessory or induction-power consuming apparatus may be positioned proximate to the interface surface. The housing of the charging apparatus may include a power source and a power-transferring coil coupled to the power source and positioned below the interface surface. A thermal mass may be positioned within the housing and spaced apart from the interface surface. The housing may include a thermal path that is configured to conduct heat from the interface surface to the thermal mass.

Claims

1. A charging apparatus comprising:

a housing including an upper portion defining an interface surface and a lower portion defining a bottom wall;

a power source positioned within the housing;

a power-transferring coil coupled to the power source and positioned within the housing and below the interface surface;

a thermal mass positioned within the lower portion of the housing and extending along the bottom wall;

a thermal path configured to conduct heat from the interface surface to the thermal mass; and

an electromagnetic shield positioned adjacent and extending along at least three sides of the power-transferring coil and separated from the thermal mass by a gap such that the electromagnetic shield is between the power-transferring coil and the thermal mass, the electromagnetic shield shields the thermal mass from a time-varying magnetic field generated by the power-transferring coil and directs electrical flux associated with the power-transferring coil toward the interface surface and away from the thermal mass.

2. The charging apparatus of claim 1, further comprising:

a cable attached to the housing and comprising;

a conductor pair; and

a thermally conductive shield layer surrounding the conductor pair, wherein the conductive shield layer is thermally coupled to the thermal mass.

3. The charging apparatus of claim 2, wherein:

the cable further comprises a thermally conductive sheath enclosing the conductor pair and the thermally conductive shield layer and

the thermally conductive sheath is thermally coupled to the thermally conductive shield layer.

4. The charging apparatus of claim 1, wherein:

the interface surface is configured to engage a surface of an external power-consuming apparatus; and

the power-transferring coil is configured to inductively couple with a power-consuming coil of the external power-consuming apparatus.

5. The charging apparatus of claim 4, wherein the interface surface is configured to direct heat from the external power-consuming apparatus to the thermal path.

6. The charging apparatus of claim 4, wherein the interface surface includes a surface feature that is configured to engage with the surface of the external power-consuming apparatus.

7. The charging apparatus of claim 6, wherein the surface feature includes an axially symmetric curved indentation.

8. The charging apparatus of claim 6, wherein:

the surface feature includes a rib feature configured to provide an air gap between the interface surface and the surface of the external power-consuming apparatus; and

the air gap is configured to reduce an amount of heat from passing from the charging apparatus to the external power-consuming apparatus.

9. The charging apparatus of claim 4, wherein the thermal path comprises one or more thermal vias.

10. An inductive power-transferring apparatus comprising:

a housing comprising;

an upper portion defining an interface surface having a first thermal conductivity;

a base portion incorporating a thermal mass extending along a bottom wall; and

a thermal path thermally coupling the interface surface and the thermal mass and having a second thermal conductivity greater than the first thermal conductivity;

a power source positioned within the housing;

a power-transferring coil coupled to the power source and positioned within the housing below the interface surface; and

an electromagnetic shield positioned adjacent and extending along at least three sides of the power-transferring coil and separated from the thermal mass by a gap such that the electromagnetic shield is between the power-transferring coil and the thermal mass, the electromagnetic shield shields the thermal mass from a time-varying magnetic field generated by the power-transferring coil and directs electrical flux associated with the power-transferring coil toward the interface surface and away from the thermal mass.

11. The inductive power-transferring apparatus of claim 10, wherein the thermal path includes a thermal via extending from the interface surface to the thermal mass.

12. The inductive power-transferring apparatus of claim 10, wherein the thermal path is formed from one of a metal, a polymer doped with a thermally conductive material, or a ceramic doped with the thermally conductive material.

13. The inductive power-transferring apparatus of claim 10, wherein at least a portion of the thermal mass is an electromagnetic interference shield.

14. The inductive power-transferring apparatus of claim 10, wherein the upper portion comprises an electrically insulating and thermally conducting material.

15. The inductive power-transferring apparatus of claim 10, wherein the upper portion comprises a plastic doped with thermally conductive metal filaments.

16. The inductive power-transferring apparatus of claim 10, wherein at least a portion of the thermal mass further comprises a heat sink for a component disposed within the housing.

17. The inductive power-transferring apparatus of claim 10, further comprising a processing unit that is configured to discontinue current to the power-transferring coil upon determining that a selected temperature threshold is reached.

18. The inductive power-transferring apparatus of claim 10, wherein the power-transferring coil is formed from a material including one or more of a copper alloy material, a silver alloy material, or a copper-silver alloy material.

19. A method for managing a temperature of an induction power-transferring apparatus, the method comprising:

receiving, at an interface surface of the induction power-transferring apparatus, heat from an accessory positioned proximate to the interface surface;

directing the heat received at the interface surface through at least one thermal path to a thermal mass extending along a bottom wall of the induction power-transferring apparatus;

directing heat within the thermal mass to a cable for connecting to a power outlet, the cable comprising a thermally conductive layer; and

shielding the thermal mass from a time-varying magnetic field generated by a power-transferring coil with an electromagnetic shield, the electromagnetic shield positioned adjacent and extending along at least three sides of the power-transferring coil and separated from the thermal mass by a gap such that the electromagnetic shield is between the power-transferring coil and the thermal mass, the electromagnetic shield directing electrical flux associated with the power-transferring coil toward the interface surface and away from the thermal mass.

20. The method of claim 19, wherein directing the heat within the thermal mass to the cable comprises directing heat to an electrically conductive layer surrounding a conductor pair of the cable.

21. The method of claim 19, wherein receiving the heat from the accessory comprises:

aligning the accessory to contact the interface surface;

transmitting inductive power to the accessory; and

receiving heat generated within the accessory, the heat a result of transmitting the inductive power.

22. The method of claim 21, wherein directing heat through the at least one thermal path to the thermal mass comprises directing, to the thermal mass, heat generated within the apparatus as a result of transmitting the inductive power.

23. The method of claim 19, wherein receiving heat from the accessory comprises:

aligning the accessory along an axis of the interface surface, the accessory separated from the surface of the interface surface by an air gap;

transmitting inductive power to the accessory; and

receiving heat generated within the accessory, the heat a result of transmitting inductive power;

wherein the air gap inhibits a transfer of heat from the induction power-transferring apparatus to the accessory.