Magnetic Sheet with Metal Oxide Coating for High-Frequency Wireless Power
Solution Overview
Problem
Soft magnetic metal ribbons used in wireless charging apparatuses deteriorate in frequency bands above several hundred kHz, limiting their effectiveness in emerging wireless power transmission standards like the Alliance for Wireless Power (A4WP) that operate at higher frequencies.
Innovation Solution
A magnetic sheet with metal oxide coating layers formed between fragments of a metal ribbon, specifically an Iron or Cobalt-based alloy, enhances insulating properties and maintains magnetic permeability across a wide frequency range by reducing eddy current loss and incorporating protective and adhesive layers for stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a soft magnetic metal ribbon is used in wireless charging apparatuses, then thinness and high Bs characteristics are achieved, but the characteristics deteriorate in frequency bands above several hundred kHz
Solution Approach 1:
The metal ribbon is divided into multiple fragments in the thickness direction, creating a segmented structure. This segmentation reduces eddy current paths and improves frequency characteristics while maintaining the thin profile of the original ribbon. The fragments are arranged with insulating layers between them to further enhance high-frequency performance.
Solution Approach 2:
The patent creates a composite structure by combining metal ribbon fragments with insulating layers (such as oxide layers or resin layers). This composite material approach allows the magnetic sheet to maintain the advantageous properties of the metal ribbon (thinness, high Bs) while adding the frequency-resistant properties of the insulating materials, thereby resolving the contradiction between thinness and high-frequency reliability.
2Reliability
If metal oxide coating layers are formed between fragments of metal ribbon, then insulating properties and frequency characteristics are improved, but manufacturing complexity increases
Solution Approach 1:
The insulating oxide layers are formed on the metal ribbon fragments before the fragments are assembled into the final magnetic sheet structure. This preliminary action of coating the fragments with insulating material simplifies the overall manufacturing process by pre-equipping the components with necessary insulating properties, rather than requiring complex post-assembly insulation processes.
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 magnetic sheet effectively operates across various wireless power transmission standards, including A4WP, WPC, and PMA, by improving frequency characteristics and Q values, enabling efficient electromagnetic wave transmission and reception at higher frequencies.
Implementation Method 1
A magnetic sheet with metal oxide coating layers formed between fragments of a metal ribbon, specifically an Iron or Cobalt-based alloy, enhances insulating properties and maintains magnetic permeability across a wide frequency range by reducing eddy current loss
Implementation Method 2
The magnetic sheet blocks a magnetic field generated in the reception coil from arriving at the battery and efficiently transmits electromagnetic waves generated by the wireless power transmitting apparatus to a wireless power receiving apparatus
Implementation Method 3
The metal oxide coating layer may be an atomic layer deposition layer
Data Source
AI summary
A magnetic sheet includes one or more magnetic layers formed of a metal ribbon, the metal ribbon includes fragments with metal oxide coating layers formed in spaces between the fragments.