Preferentially Magnetically Oriented Ferrites for Improved Power Transfer

• US 20170092409A1
• Filed: 09/21/2016
• Published: 03/30/2017
• Est. Priority Date: 09/30/2015
• Status: Abandoned Application

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Graham, Christopher S.
• Application Number:
  US15/272,379
• Publication Number:
  US 20170092409A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01F 27/24 Magnetic cores
• CPC Class Codes: H01F 27/255 made from particles H01F27/26 takes precedence
• CPC Class Codes: H01F 27/28 Coils; Windings; Conductive connections
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H01F 41/02 for manufacturing cores, coils, or magnets H01F41/14 takes precedence; for dynamo-electric machines H02K15/00
• CPC Class Codes: H01F 41/04 for manufacturing coils coils for transformer or inductances H01F27/28
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment

Abstract

The present disclosure includes systems and methods for magnetically orienting ferrites in an inductive power transfer system. In one example embodiment, a method for forming a ferrite element having oriented magnetic dipoles includes heating a ferrite element to a first temperature, the ferrite element comprising a non-magnetic matrix having magnetic particulates suspended therein, and, while heating, applying an external magnetic field to the ferrite element to align magnetic dipoles of the particulates with the direction of the magnetic field.

Claims

1. A method for forming a ferrite element having oriented magnetic dipoles, comprising:

heating the ferrite element to a first temperature, the ferrite element comprising a non-magnetic matrix having magnetic particulates suspended therein; and

while heating, applying an external magnetic field to the ferrite element, thereby aligning the magnetic dipoles of the particulates with the magnetic field.

2. The method of claim 1, wherein:

heating the ferrite element to the first temperature partially sinters the ferrite element; and

further comprising heating the partially-sintered ferrite element to a second temperature to fully sinter the ferrite element; and

applying the external magnetic field to the ferrite element occurs between heating the ferrite element to the first temperature and heating the partially-sintered ferrite element to the second temperature.

3. The method of claim 1, wherein the ferrite element is configured to hold an induction coil.

4. The method of claim 3, wherein the aligned magnetic dipoles of the particulates are aligned with a magnetic field of the induction coil during operation of the induction coil.

5. The method of claim 4, wherein the aligned magnetic dipoles increase the permeability of the ferrite element.

6. The method of claim 5, wherein the increased permeability of the ferrite element improves power transmission efficiency of the induction coil.

7. A method for improving power transmission in an inductive power transfer system, comprising:

forming a coil substrate from a ferrite material having substantially unidirectionally oriented magnetic dipoles;

disposing an induction coil on a surface of the coil substrate.

8. The method of claim 7, wherein forming the coil substrate comprises:

heating the ferrite material to a threshold temperature; and

applying a magnetic field to the ferrite material during heating to align magnetic dipoles of the ferrite material with the magnetic field.

9. The method of claim 7, wherein the magnetic dipoles of the ferrite material are oriented in a direction corresponding to a direction of an intersecting magnetic field of the induction coil.

10. The method of claim 7, further comprising:

forming two or more substrate components from a ferrite material, the two or more substrate components each comprised of oriented magnetic dipoles; and

joining the two or more substrate components to form the coil substrate.

11. The method of claim 10, wherein forming two or more substrate components comprises:

forming two or more substrate parts each forming a distinct portion of a coil substrate having a combined shape capable of receiving the induction coil;

heating each of the two or more substrate parts to a threshold temperature; and

during heating of each of the two or more substrate parts, applying a magnetic field to each of the two or more substrate parts to generally align magnetic dipoles of the ferrite material with the magnetic field being applied.

12. The method of claim 10, wherein joining the two or more substrate components results in a coil substrate having an aggregate magnetic dipole orientation that substantially aligns with a magnetic field of the induction coil in an inductive power transfer system.

13. An induction coil substrate, comprising:

a ferrite material having substantially unidirectionally oriented magnetic dipoles; and

a coil-receiving region on a surface of the substrate.

14. The induction coil substrate of claim 13, further comprising an induction coil in the coil-receiving region.

15. The induction coil substrate of claim 14, wherein the magnetic dipoles of the ferrite material are substantially parallel to a magnetic field of the induction coil.

16. The induction coil substrate of claim 15, wherein the alignment of the magnetic dipoles improves power transmission efficiency of the induction coil.

17. The induction coil substrate of claim 13, wherein the substrate is formed of two or more parts, each comprised of a ferrite material having substantially unidirectionally oriented magnetic dipoles.

18. The induction coil substrate of claim 17, wherein the magnetic dipoles of each part respectively substantially align with an intersecting magnetic field of an induction coil in the coil-receiving region.

19. The induction coil substrate of claim 13, wherein the ferrite material having substantially unidirectionally oriented magnetic dipoles is formed in a process that simultaneously sinters and applies an external magnetic field to the substrate.

20. The induction coil substrate of claim 19, wherein applying an external magnetic field substantially aligns the magnetic dipoles of the ferrite material with the magnetic field.