Wireless Power Transfer Coil Shielding for Stray Field Cancellation

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Solution Overview

Problem

Charging electric vehicles wirelessly faces challenges such as time efficiency, ease of recharging, and management of stray electromagnetic fields that can impact surrounding environments and vehicle components.

Innovation Solution

The implementation of a wireless charge assembly with a shielding body, capacitor bank assembly, and charge coil assembly, where the coil assembly includes shielding turns with opposite current circulation directions to cancel stray electromagnetic fields, and a conductor penetration through the shielding body to manage field distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If wireless charging is implemented without shielding, then power transfer can occur, but stray electromagnetic fields are generated that impact surrounding environments and vehicle components

Engineering Contradiction:

Improvepower transfer efficiencyVSAvoidstray electromagnetic fields

Core Design Contradiction:

Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent applies shielding turns that generate electromagnetic fields in the opposite direction to cancel out the stray fields produced by the charging coils. This converts the harmful stray electromagnetic fields into a beneficial cancellation effect, reducing environmental impact while maintaining power transfer efficiency

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces shielding turns at specific locations (opposing ends of the coil body within the charging plane) with specific current circulation directions. This localized application of shielding elements targets the specific areas where stray fields are generated, providing effective cancellation without compromising overall power transfer

Inventive Principle:

Principle #3Local quality

2Object-generated harmful factors

If shielding turns are added to cancel stray fields, then electromagnetic field cancellation is improved, but device complexity increases

Engineering Contradiction:

Improvestray electromagnetic fieldsVSAvoidcoil assembly structure

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines the shielding turns with the existing coil structure by arranging them on opposing ends of the same coil body within the charging plane. This merging approach integrates the shielding function into the existing charging assembly rather than adding separate shielding components, thereby reducing overall device complexity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent divides the coil assembly into functional segments: charging coils for power transfer and shielding turns for field cancellation. This segmentation allows each component to perform its specific function efficiently while maintaining a organized and manageable structure

Inventive Principle:

Principle #1Segmentation

3Object-generated harmful factors

If conductor penetration through shielding body is implemented, then field distribution is managed, but manufacturing complexity increases

Engineering Contradiction:

Improvefield distributionVSAvoidassembly construction

Core Design Contradiction:

Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The conductor penetration through the shielding body serves multiple functions: it provides electrical connection between components and manages field distribution simultaneously. This multi-functionality reduces the need for separate components, thereby simplifying manufacturing despite the penetration requirement

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enhances the efficiency of wireless charging by reducing stray electromagnetic fields and improving power transfer efficiency while adhering to environmental guidelines, thus optimizing the charging process.

Implementation Method 1

The shielding turns may be arranged to circulate current in a shielding direction defined opposite to a charging direction in which current circulates via corresponding adjacent coil turns

Methodology Applied

Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

a capacitor bank assembly arranged on one side of the shielding body

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS12558978B2Devices, systems, and methods for capacitance in wireless power transfer

Publication Date: 2026.02.24 VOLKSWAGEN AG

AI summary

Devices, systems, and methods related to wireless power transfer for vehicles can include a wireless power transfer assembly which may be coupled with the vehicle chassis. The assembly can include a shielding body, and a power coil assembly arranged on one side of the shielding body for wireless power transfer. The assembly can include a capacitor bank assembly for providing capacitance for wireless power transfer. The capacitor bank assembly can be arranged on an opposite side of the shielding body, and can include at least one capacitor bank having at least one compression plate and a number of capacitors connected in series via a bus bar assembly. The number of capacitors of the at least one capacitor bank can be arranged between the corresponding at least one compression plate and the shielding body, and the at least one compression plate can be secured with the shielding body for clamping.