Power Receiving Coil Shield Segmentation for Leakage Control

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Solution Overview

Problem

The existing power receiving and transmitting devices with shields to suppress electromagnetic field leakage incur increased costs and weight due to the shape and material requirements of the shields.

Innovation Solution

A configuration where shields are strategically placed only at the ends of the power receiving and transmitting coils, avoiding the center portion to minimize material usage and prevent electromagnetic field leakage, thereby reducing the cost and weight of the shields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a shield is provided to cover the power receiving coil, then electromagnetic field leakage is suppressed, but the shape and weight of the shield are increased and cost increases

Engineering Contradiction:
Improveelectromagnetic field leakageVSAvoidshield weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of stationary object

Solution Approach 1:

The shield is divided into multiple separate shields corresponding to different regions (first region, second region, third region, fourth region) around the power receiving coil. Each shield is positioned at specific locations where electromagnetic field leakage is most intense, rather than using a single continuous shield covering the entire coil area. This segmentation reduces the total amount of shielding material required while maintaining effective suppression of electromagnetic field leakage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shield configuration is optimized based on the local characteristics of electromagnetic field radiation. The patent identifies that electromagnetic fields are radiated intensively from the sides of the power receiving coil, so shields are specifically positioned at these high-radiation areas (first and second regions) while reducing or omitting shields in areas with less radiation (third and fourth regions). This local quality approach ensures effective leakage suppression where needed while minimizing shield material and weight.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If a shield is provided to cover the power receiving coil, then electromagnetic field leakage is suppressed, but the cost required for the shield increases

Engineering Contradiction:
Improveelectromagnetic field leakageVSAvoidshield cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The shield is divided into multiple separate shields corresponding to different regions (first region, second region, third region, fourth region) around the power receiving coil. Each shield is positioned at specific locations where electromagnetic field leakage is most intense, rather than using a single continuous shield covering the entire coil area. This segmentation reduces the total amount of shielding material required while maintaining effective suppression of electromagnetic field leakage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shield configuration is optimized based on the local characteristics of electromagnetic field radiation. The patent identifies that electromagnetic fields are radiated intensively from the sides of the power receiving coil, so shields are specifically positioned at these high-radiation areas (first and second regions) while reducing or omitting shields in areas with less radiation (third and fourth regions). This local quality approach ensures effective leakage suppression where needed while minimizing shield material and weight.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If shields are placed at the ends of the power receiving coil, then electromagnetic field leakage is suppressed, but material requirements are reduced

Engineering Contradiction:
Improveelectromagnetic field leakageVSAvoidshield material
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The shield configuration is optimized based on the local characteristics of electromagnetic field radiation. The patent identifies that electromagnetic fields are radiated intensively from the sides of the power receiving coil, so shields are specifically positioned at these high-radiation areas (first and second regions) while reducing or omitting shields in areas with less radiation (third and fourth regions). This local quality approach ensures effective leakage suppression where needed while minimizing shield material and weight.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of providing complete coverage with shields around the entire power receiving coil, the patent applies shields only partially - specifically at the first and second regions where electromagnetic field radiation is most intense. This partial action approach provides sufficient suppression of harmful electromagnetic field leakage while significantly reducing the quantity of shielding material required compared to full coverage.

Inventive Principle:
Principle #16Partial or excessive action

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 configuration effectively suppresses electromagnetic field leakage without increasing costs, reducing material requirements and maintaining the functionality of the shields, while minimizing the risk of eddy current-induced temperature issues.

Implementation Method 1

a power transmitting device which transmits electric power to a power receiving device contactlessly

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a power receiving device which receives electric power from a power transmitting device contactlessly

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a shield which surrounds at least a part of the power receiving coil when seen from a direction along the coil winding axis

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentEP3076412B1Power-receiving device and power-transmitting device
Publication Date: 2018.07.25 TOYOTA JIDOSHA KK
  • EP3076412B1 patent drawingFigure 1
  • EP3076412B1 patent drawingFigure 2
  • EP3076412B1 patent drawingFigure 3

AI summary

A power receiving unit (210) adopted for this power receiving device includes a core unit (260) having a plate-like shape and including a side surface, an upper surface and a lower surface, and a power receiving coil (250) helically wound about a coil winding axis (02) to surround the core unit (260) including the upper and lower surfaces, the shield (240) including a first shield (240a) disposed on the side of one end of the power receiving unit (210) in an axial direction of the coil winding axis (02), and a second shield (240b) disposed on the side of the other end of the power receiving unit (210) in the axial direction of the coil winding axis (02), the shield (240) being absent at least at a location directly above a center portion of the power receiving unit (210).