3D Shaped Inductive Charging Coil for Wireless Power Transfer

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Solution Overview

Problem

Conventional inductive coils with planar geometry face inefficiencies in wireless charging due to distance gaps when used on three-dimensional charging surfaces, leading to reduced power transfer efficiency, and existing solutions for three-dimensional coils are time-consuming and lack precision.

Innovation Solution

A method of creating three-dimensional inductive coil assemblies through a multi-layered structure comprising conductive layers and an insulating layer, which are molded into a desired shape using processes like compression molding or vacuum forming, allowing precise conformation to charging surfaces and reducing distance between transmitter and receiver coils.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional planar inductive coils are used on three-dimensional charging surfaces, then manufacturing is simple, but distance gaps increase and power transfer efficiency decreases

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidcoil geometry
Core Design Contradiction:
Loss of energyVSShape

Solution Approach 1:

The patent transitions from conventional two-dimensional planar coils to three-dimensional coils that conform to curved charging surfaces. The multi-layered structure with conductive traces on both top and bottom surfaces of an insulating substrate enables vertical stacking and three-dimensional shaping, allowing the coil to adapt to non-planar surfaces and maintain consistent proximity to the charging surface, thereby eliminating distance gaps and improving power transfer efficiency.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the geometric parameters of the coil from flat two-dimensional geometry to three-dimensional geometry with varying heights and curvatures. By modifying the shape parameters to include vertical dimension and curvature, the coil can conform to three-dimensional charging surfaces while maintaining optimal spacing for electromagnetic coupling, thus resolving the contradiction between simple manufacturing and power transfer efficiency.

Inventive Principle:
Principle #35Parameter changes

2Shape

If wound coils are used to achieve three-dimensional geometry, then coil shape adaptability improves, but manufacturing time increases and precision decreases

Engineering Contradiction:
Improvecoil geometry precisionVSAvoidmanufacturing time
Core Design Contradiction:
ShapeVSLoss of time

Solution Approach 1:

The patent replaces the mechanical winding process with a printing-based manufacturing approach. Conductive traces are deposited onto insulating substrate layers using printing techniques, and the multi-layered structure is then molded into the desired three-dimensional shape. This substitution of mechanical winding with printing and molding processes significantly reduces manufacturing time while improving geometric precision and consistency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs a composite multi-layered structure consisting of insulating substrate layers with conductive traces deposited on them. This composite approach allows the coil to achieve complex three-dimensional geometries through molding while maintaining precise trace patterns and spacing. The combination of printed conductive layers and molded insulating materials enables high-precision three-dimensional coil fabrication without time-consuming mechanical winding.

Inventive Principle:
Principle #40Composite materials

3Loss of energy

If three-dimensional molded coil structure is implemented, then power transfer efficiency improves, but manufacturing complexity increases

Engineering Contradiction:
Improvecharging efficiencyVSAvoidmanufacturing process simplicity
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The patent merges multiple functions into a single integrated manufacturing process. The conductive traces are printed onto insulating substrate layers, and then the entire multi-layered structure is molded into the final three-dimensional coil shape in one operation. This combining of trace deposition and three-dimensional forming into a unified printing and molding process simplifies manufacturing compared to separate winding and shaping operations, while maintaining the charging efficiency benefits of three-dimensional geometry.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enhances coil shape control, precision, and manufacturing efficiency, improving power transfer efficiency by precisely conforming to charging surfaces and reducing gaps between coils.

Implementation Method 1

an inductive coil within the charging device (a 'transmitter') generates a time-varying electromagnetic field from, for example, an alternating current (AC) flowing through the coil. This field generates a corresponding time-varying current within a second inductive coil in the electronic device (a 'receiver') by way of electromagnetic induction

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the molding can include a compression molding process

Methodology Applied
Scientific EffectCompression molding: Compression

Implementation Method 3

the molding can include a vacuum forming process

Methodology Applied
Scientific EffectVacuum forming: Vacuum

Data Source

PatentEP3133617B13D shaped inductive charging coil and method of making the same
Publication Date: 2021.05.12 APPLE INC
  • EP3133617B1 patent drawingFigure 1
  • EP3133617B1 patent drawingFigure 2
  • EP3133617B1 patent drawingFigure 3

AI summary

A three-dimensional inductive charging coil assembly and a method of making the same. The method can include patterning a first conductive layer affixed to a first surface of an insulating layer to form a coil configured to transmit or receive power, patterning a second conductive layer affixed to a second surface of the insulating layer opposite the first surface to form a conductive trace element, and electrically coupling the coil and the conductive trace element. The coil, insulating layer, and conductive trace element can be molded (e.g., simultaneously) into a three dimensional shape. In some embodiment, the molding can include a thermoforming process such as compression molding, vacuum forming, or the like.