Overlapped Multilayer Magnetic Sheet to Prevent Flux Leakage

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Solution Overview

Problem

The existing methods for manufacturing multilayer magnetic sheets for contactless charging, particularly for electric vehicles, face challenges in reducing man-hours and preventing magnetic flux leakage, as they require extensive stacking of alloy strips which leads to continuous magnetic gaps and decreased magnetic permeability and Q factor.

Innovation Solution

The configuration involves aligning and stacking laminate substrates with overlapping long side portions to form a multilayer magnetic sheet, eliminating continuous magnetic gaps and maintaining high magnetic permeability and Q factor, thereby reducing manufacturing time and improving magnetic characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If alloy strips are stacked to form a multilayer magnetic sheet, then the width of the magnetic sheet is increased, but the number of stacking operations increases leading to large man-hours

Engineering Contradiction:
Improvewidth of magnetic sheetVSAvoidman-hours for stacking
Core Design Contradiction:
Area of stationary objectVSLoss of time

Solution Approach 1:

The magnetic sheet is divided into multiple laminate substrates, each comprising multiple stacked alloy strips. By segmenting the overall stacking task into smaller substrate units that can be prepared separately and then assembled, the manufacturing process becomes more efficient and manageable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple alloy strips are nested within each laminate substrate, forming a compact multi-layer structure. These substrates are then arranged and stacked to form the complete magnetic sheet, creating a nested organizational structure that reduces overall stacking operations.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Productivity

If laminate substrates are stacked to form a multilayer magnetic sheet, then manufacturing efficiency is improved, but continuous magnetic gaps form between substrates reducing magnetic permeability and Q factor

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidmagnetic permeability and Q factor
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Adjacent laminate substrates are arranged with asymmetric offset positioning, where the alloy strips in one substrate do not align directly with those in adjacent substrates. This asymmetric arrangement prevents continuous magnetic gaps from forming across the entire magnetic sheet, thereby maintaining high magnetic permeability and Q factor while still benefiting from the manufacturing efficiency of the laminate substrate approach.

Inventive Principle:
Principle #4Asymmetry

3Power

If a magnetic sheet is used for contactless charging in electric vehicles, then power transmission capability is improved, but magnetic flux leakage to other devices increases

Engineering Contradiction:
Improvepower transmission capabilityVSAvoidmagnetic flux leakage
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The magnetic sheet is segmented into multiple laminate substrates with asymmetrically positioned alloy strips. This segmentation creates a distributed magnetic path structure that confines magnetic flux more effectively within the intended charging area, reducing leakage to surrounding devices while maintaining the required power transmission capability.

Inventive Principle:
Principle #1Segmentation

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 approach results in a multilayer magnetic sheet with reduced man-hours and enhanced magnetic performance, capable of efficiently preventing magnetic flux leakage and maintaining high permeability and Q factor, suitable for contactless charging applications.

Implementation Method 1

a magnetic sheet may be installed as a coil yoke on a side of the transmission coil opposite to contact surfaces of the power feeding device and the power receiving device. The magnetic sheet disposed in this manner has a role as a magnetic shielding material for preventing leakage of the magnetic flux during the charging

Methodology Applied
Scientific EffectMagnetic shielding: Magnetic Field

Implementation Method 2

a magnetic sheet may be installed as a coil yoke on a side of the transmission coil opposite to contact surfaces of the power feeding device and the power receiving device. The magnetic sheet disposed in this manner has a role as a yoke member for refluxing the magnetic flux generated in the coil during the charging

Methodology Applied
Scientific EffectMagnetic flux reflux: Magnetic Field

Implementation Method 3

a magnetic flux generated in a primary transmission coil of a power feeding device generates an electromotive force in a secondary transmission coil of a power receiving device through casings of the power feeding device and the power receiving device, whereby a power is supplied

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4258296A1Multilayer magnetic sheet
Publication Date: 2023.10.11 PROTERIAL LTD
  • EP4258296A1 patent drawingFigure 1
  • EP4258296A1 patent drawingFigure 2
  • EP4258296A1 patent drawingFigure 3

AI summary

A multilayer magnetic sheet (400) comprises laminate substrates (300). Each of the laminate substrates (300) is formed in a band shape having a short side and a long side and comprises magnetic strips (20) stacked in layers. The laminate substrates (300) are aligned and arranged in a plate shape in a direction, in which the long sides are adjacent to each other and the short sides extend. The laminate substrates (300) aligned and arranged in the plate shape are stacked in layers in a thickness direction of the laminate substrates (300). Long side portions of the laminate substrates (300) including the long sides and vicinities of the long sides overlap each other.