Fe-B-Si Soft Magnetic Alloy for Wireless Power

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Solution Overview

Problem

Fe-based soft magnetic alloys used in wireless charging systems face challenges with low saturated magnetic flux density and high manufacturing costs at high frequency bands, and existing materials struggle with processing and cost efficiency.

Innovation Solution

A soft magnetic alloy composition of Fe, B, and Si, with specific atomic percentage ranges (84.5-91.0% Fe, 5.3-9.0% B, and 3.8-6.5% Si), providing high saturated magnetic flux density and low AC magnetic loss, suitable for frequency bands of 150 kHz to 250 kHz, and processed through annealing for enhanced properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If Fe-Si soft magnetic alloy is used, then saturated magnetic flux density is improved (1.5 T to 1.9 T), but resistivity is too low for high frequency operation (110 to 250 kHz)

Engineering Contradiction:
Improvesaturated magnetic flux densityVSAvoidhigh frequency applicability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent uses a composite alloy system combining Fe, B, and Si elements. The Fe provides high saturated magnetic flux density, while B and Si work synergistically to increase resistivity for high frequency operation. This composite approach allows simultaneous optimization of magnetic performance and electrical properties that cannot be achieved with simple Fe-Si alloys.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific compositional parameters within defined ranges: Fe (82-90 at%), B (5-15 at%), and Si (3-10 at%). By precisely controlling these parameter ranges, the alloy achieves both high saturated magnetic flux density (>1.8 T) and sufficiently high resistivity for 110-250 kHz operation, resolving the contradiction between magnetic strength and frequency applicability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If amorphous soft magnetic alloy including Fe and metalloid element is used, then frequency band applicability is improved (110 to 250 kHz), but saturated magnetic flux density decreases (1.56 T or less)

Engineering Contradiction:
Improvefrequency band applicabilityVSAvoidsaturated magnetic flux density
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent employs a composite amorphous alloy structure combining Fe with specific ratios of B and Si. This composite composition enables the material to simultaneously achieve high frequency applicability (110-250 kHz) through amorphous structure and high saturated magnetic flux density (>1.8 T) through optimized elemental composition, overcoming the limitation of conventional amorphous alloys.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent defines specific compositional parameter ranges: Fe (82-90 at%), B (5-15 at%), and Si (3-10 at%). These parameter optimizations ensure the alloy maintains amorphous structure for high frequency performance while achieving saturated magnetic flux density exceeding 1.8 T, thus resolving the contradiction between frequency applicability and magnetic strength.

Inventive Principle:
Principle #35Parameter changes

3Strength

If soft magnetic alloy with high saturated magnetic flux density is used, then manufacturing cost increases

Engineering Contradiction:
Improvesaturated magnetic flux densityVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent optimizes compositional parameters to use predominantly Fe (82-90 at%), which is abundant and cost-effective, combined with smaller amounts of B (5-15 at%) and Si (3-10 at%). This parameter optimization achieves high saturated magnetic flux density (>1.8 T) while maintaining cost-effectiveness through efficient use of expensive alloying elements, resolving the contradiction between performance and manufacturing cost.

Inventive Principle:
Principle #35Parameter changes

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 alloy achieves high saturated magnetic flux density, low AC magnetic loss, and improved processing capabilities, reducing material costs and enabling efficient wireless power transmission and reception in high-frequency wireless charging systems.

Implementation Method 1

the soft magnetic sheet of the wireless power transmitting apparatus, and the soft magnetic sheet of the wireless power receiving apparatus may shield electromagnetic waves radiated from the transmission coil and electromagnetic waves received by the reception coil

Methodology Applied
Scientific EffectElectromagnetic shielding: Absorption (EM radiation)

Implementation Method 2

processed through annealing for enhanced properties

Methodology Applied
Scientific EffectAnnealing: Annealing

Data Source

PatentEP3029690B1Soft magnetic alloy, wireless power transmitting apparatus, and wireless power receiving apparatus including the same
Publication Date: 2020.03.18 LG INNOTEK CO LTD
  • EP3029690B1 patent drawingFigure 1~2
  • EP3029690B1 patent drawingFigure 3~5
  • EP3029690B1 patent drawingFigure 6

AI summary

The present invention relates to a soft magnetic alloy and, more specifically, to a soft magnetic alloy used in electric transformers, pulse generators, compressions, electric chokes, energy-accumulating inductors, magnetic sensors, or the like, and a wireless power transmitting apparatus (200 ; 1200) and wireless power receiving apparatus (300 ; 1300) including the soft magnetic alloy.