Wireless Charging Shield Sheet with Segmented Magnetic Layers
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Solution Overview
Problem
Existing wireless charging shield sheets require multiple layers to prevent magnetic flux leakage, leading to increased size and reduced charging efficiency due to high magnetic loss and eddy current issues.
Innovation Solution
A shield sheet comprising a collar magnetic sheet with high magnetic permeability and a center magnetic sheet with fragmented layers, where the collar sheet is perpendicular to eddy currents and the center sheet suppresses long free-path eddy currents, allowing for a compact design and enhanced charging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple layers of magnetic sheets are stacked to prevent magnetic flux leakage, then shielding performance is improved, but device size and thickness increase
Solution Approach 1:
The magnetic sheet is divided into two distinct functional regions: a collar magnetic sheet with high magnetic permeability for shielding, and a center magnetic sheet with fragmented structure for loss reduction. This segmentation allows each region to optimize its specific function without requiring multiple stacked layers, thereby reducing overall thickness while maintaining shielding performance.
Solution Approach 2:
Different regions of the magnetic sheet are given different local properties: the collar region uses intact high-permeability material for maximum shielding, while the center region uses fragmented material to suppress eddy currents. This local differentiation resolves the contradiction by optimizing each area for its specific purpose rather than using a uniform structure throughout.
2Reliability
If magnetic material is used to distribute magnetic field and prevent energy loss, then shielding performance is improved, but eddy current loss increases causing heat generation
Solution Approach 1:
The center magnetic sheet is segmented into fragmented strips that are stacked with insulating adhesive layers. This segmentation breaks the continuous conductive path, preventing long free-path eddy currents while maintaining the magnetic shielding effect through the stacked structure.
Solution Approach 2:
An insulating adhesive layer is introduced as an intermediary between the fragmented magnetic strips. This adhesive layer blocks the formation of continuous eddy current paths while allowing the magnetic field to pass through, thereby reducing eddy current loss without compromising shielding performance.
3Reliability
If magnetic permeability is increased to improve shielding, then shielding performance is improved, but magnetic loss increases reducing charging efficiency
Solution Approach 1:
The collar magnetic sheet uses high magnetic permeability material for optimal shielding performance, while the center magnetic sheet uses fragmented material with controlled permeability to minimize losses. This local quality differentiation allows the system to achieve high shielding where needed while minimizing energy loss in regions where eddy currents would otherwise form.
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 reduces eddy-current losses and maintains high magnetic permeability, enabling a smaller stacking number of sheets for the same shielding performance, facilitating miniaturization and increased charging efficiency.
Implementation Method 1
the collar magnetic sheet comprises at least one first magnetic permeable layer with high magnetic permeability, which is a nanocrystal strip, an amorphous strip or a metallic soft magnetic strip with high magnetic permeability
Implementation Method 2
the center magnetic sheet comprises at least two second magnetic permeable layers stacked one on another, which are fragmented nanocrystal strips, fragmented amorphous strips or fragmented metallic soft magnetic strips
Data Source
AI summary
A shield sheet comprises a collar magnetic sheet and a center magnetic sheet. The collar magnetic sheet is provided with a hole adapted to the center magnetic sheet. The center magnetic sheet has one end fixed in the hole and the other end protruding out of the collar magnetic sheet. The collar magnetic sheet comprises at least one first magnetic permeable layer, which is a nanocrystal strip, an amorphous strip or a metallic soft magnetic strip. The center magnetic sheet comprises at least two second magnetic permeable layers stacked one on another, which are fragmented nanocrystal strips, fragmented amorphous strips or fragmented metallic soft magnetic strips. Fewer nanocrystal strips are stacked for the collar magnetic sheet in the shield sheet of the invention, facilitating the miniaturization of the shield sheet and increasing charging efficiency.