Coil Unit Shield Step Design for Wireless Charging
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Solution Overview
Problem
The coefficient of coupling in wireless charging systems is reduced due to the magnetic flux being interlinked with the metal members of the coil units, which limits the efficiency of wireless charging.
Innovation Solution
A coil unit design with a longer separation distance from the ferrite's outer peripheral edge to the metal member and a coil that stretches close to the ferrite's outer edge, preventing magnetic flux interlinkage with metal members and increasing the amount of magnetic flux incident on the exposed part of the ferrite.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the length from the outer peripheral edge of the ferrite to the peripheral wall of the housing body is short, then the device size is reduced, but the magnetic flux is interlinked with the peripheral wall which reduces the coefficient of coupling
Solution Approach 1:
The patent introduces a metal member as an intermediary component positioned between the ferrite and the peripheral wall. This metal member acts as a magnetic flux barrier that prevents the magnetic flux from being interlinked with the peripheral wall, thereby maintaining a high coefficient of coupling even when the device size is reduced.
Solution Approach 2:
The patent applies local quality by creating an exposed part of the ferrite through a step portion in the shield, while simultaneously introducing a metal member with specific magnetic properties in a localized region. This allows different parts of the device to have different magnetic characteristics - the exposed part allows magnetic flux passage while the metal member blocks flux from reaching the peripheral wall.
2Reliability
If the coil is positioned close to the ferrite to increase coupling, then the coefficient of coupling increases, but the magnetic flux may be interlinked with metal members
Solution Approach 1:
The metal member serves as an intermediary that selectively interacts with magnetic flux. By positioning it appropriately, it blocks harmful flux interlinkage with the peripheral wall while allowing the coil to remain close to the ferrite for high coupling efficiency.
Solution Approach 2:
The patent converts the potentially harmful effect of magnetic flux interlinkage with metal members into a beneficial configuration. The metal member is strategically positioned to block flux from reaching the peripheral wall, transforming what could be a source of loss into a mechanism for directing flux through the desired path via the exposed part of the ferrite.
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
This design enhances the coefficient of coupling, improving wireless charging efficiency by ensuring more magnetic flux is incident on the exposed part of the ferrite, thereby increasing the efficiency of power transfer between coil units.
Implementation Method 1
a ferrite plate (25), a coil (15), a shield (26), and a metal member (28) provided in the housing (20)
Implementation Method 2
a coil (15), a shield (26), and a metal member (28) provided in the housing (20)... The coil is provided on the side of the second principal surface
Implementation Method 3
The shield (26) is provided on the side of the first principal surface... The shield has an outer peripheral edge including a step portion (26d) extending away from the first principal surface (25a)
Data Source
AI summary
A power-reception-side coil unit includes: a housing, a ferrite, a power reception coil, a shield, and a metal member. The metal member includes a peripheral wall, a partition wall, and a shield. The ferrite includes a first principal surface, and a second principal surface. The power reception coil is provided on the side of the second principal surface, and the shield is provided on the side of the first principal surface. The shield has an outer peripheral edge including a step portion extending away from the first principal surface. The ferrite includes an exposed part exposed through the shield by forming the step portion. In the separation direction from the outer peripheral edge of the ferrite plate to the metal member, the length from the outer peripheral edge of the ferrite plate to the metal member is longer than the length of the exposed part.