Fe-Cu-B Nanocrystalline Alloy for Wireless Charging Shield
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Solution Overview
Problem
Ferrous soft magnetic alloys used in wireless power transceiving systems face challenges such as low saturation magnetic flux density, high coercive force, and difficulty in processing into thin flake forms, which limit power transmission capacity and efficiency.
Innovation Solution
A wireless charging apparatus utilizing a soft magnetic alloy with a chemical formula Fe100−x−yCuxBy, where x ranges from 0.1 at % to 1.7 at % and y from 2.3 at % to 9.6 at %, processed into a flake form through ball milling and heat treatment, with grains sized between 10 nm and 99 nm, achieving a saturation magnetic flux density of 1.7 T or more and coercive force of 40 Oe or less, and bonded in an amorphous matrix using a water quenching method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If ferrous soft magnetic alloys are used in wireless power transceiving systems, then power transmission capacity can be increased, but saturation magnetic flux density remains low and coercive force remains high
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition (Fe100-x-yCuxBy with specific x and y ranges) and processing parameters (ball milling time, heat treatment temperature of 250-450°C) to achieve optimal magnetic properties with saturation magnetic flux density of 1.7 T or more and coercive force of 40 Oe or less
Solution Approach 2:
The patent creates a composite material structure with nanocrystalline grains (10-99 nm) dispersed in an amorphous matrix, combining the advantages of both crystalline and amorphous phases to achieve high saturation magnetic flux density and low coercive force simultaneously
2Power
If ferrous soft magnetic alloys are used, then power transmission capacity can be increased, but coercive force increases which reduces efficiency
Solution Approach 1:
The patent reduces coercive force to 40 Oe or less by optimizing alloy composition (controlling Cu and B content within specific ranges) and applying heat treatment at 250-450°C, which modifies the microstructure to reduce magnetic hysteresis losses while maintaining high power transmission capacity
3Power
If ferrous soft magnetic alloys are used, then power transmission capacity can be increased, but processing into flake form becomes difficult
Solution Approach 1:
The patent creates a composite material with nanocrystalline grains in an amorphous matrix that can be processed into flake form with aspect ratio of 10 or more, combining the high power transmission capacity of ferrous alloys with the manufacturability of flake structures suitable for wireless charging applications
4Length of stationary object
If amorphous alloys and nanocrystalline alloys are used, then shield member thickness can be reduced, but power transmission capacity decreases due to low saturation magnetic flux density
Solution Approach 1:
The patent achieves saturation magnetic flux density of 1.7 T or more in thin flake form by optimizing the alloy composition (Fe100-x-yCuxBy) and controlling grain size (10-99 nm) through heat treatment, enabling both reduced thickness and maintained power transmission capacity
Solution Approach 2:
The patent transitions from bulk materials to thin flake structures with aspect ratio of 10 or more, processing the alloy into flattened geometries that reduce thickness while maintaining effective magnetic properties for power transmission through controlled composition and nanocrystalline grain structure
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 the saturation magnetic flux density while maintaining a low coercive force, allowing for increased power transmission capacity and efficient processing into thin flake forms, suitable for both wireless power transmitters and receivers.
Implementation Method 1
the grains may be formed in an amorphous matrix made by solidifying the Fe—Cu—B alloy in a molten state using a water quenching method
Implementation Method 2
solidifying the Fe—Cu—B alloy in a molten state
Implementation Method 3
the soft magnetic alloy may be processed into the flake form through a ball milling process
Implementation Method 4
the soft magnetic alloy may be subjected to a heat treatment process in the flake form to remove residual stress
Implementation Method 5
heat treatment process to remove residual stress
Implementation Method 6
a coil disposed on the soft magnetic material
Data Source
AI summary
Disclosed are a soft magnetic alloy and a wireless charging apparatus including the soft magnetic alloy. The soft magnetic alloy has a chemical formula expressed as Fe100−x−yCuxBy (wherein x ranges from 0.1 at % to 1.7 at % and y ranges from 2.3 at % to 9.6 at %). Without adding any expensive alloying element, only iron (Fe), copper (Cu), and boron (B) are used to obtain a nanocrystalline soft magnetic alloy that has a low coercive force and a high saturation magnetic flux density. The nanocrystalline soft magnetic alloy is applied to a wireless power transmitter and a wireless power receiver. Thereby, it is possible to make a shield member thin and increase a power transmission capacity. The soft magnetic alloy is easily processed into a flake form. The soft magnetic alloy processed in this way is applied to the shield member. Thereby, it is possible to increase permeability in a surface direction.