Inductive Charging Base Assembly With Heat-Conducting Coil Support

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Solution Overview

Problem

Inductive charging devices for motor vehicles face challenges with heat dissipation, leading to early derating and reduced charging power due to temperature limitations, especially in adverse climatic conditions, as conventional materials and designs struggle to efficiently manage heat conduction and mechanical loads.

Innovation Solution

The design incorporates a base assembly with a cooling plate, a spirally wound flat coil, and a core arrangement, where heat-conducting supports made of materials with high thermal conductivity connect the coil and core body, allowing efficient heat dissipation and minimizing mechanical stress, while also using thermally conductive particles in plastic to enhance cooling and pressure distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional heat dissipation designs are used in the base assembly, then the structure is simple and cost-effective, but the temperature difference between the conductor and base plate becomes excessively large, leading to early derating and reduced charging power

Engineering Contradiction:
Improvestructural simplicityVSAvoidtemperature difference
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The base assembly is segmented into multiple functional layers: base plate, heat-conducting support, core body, and flat coil. This segmentation allows each component to perform its specific thermal function optimally, with the support acting as a dedicated heat transfer pathway between the base plate and core body, thereby reducing the overall temperature difference while maintaining structural clarity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A heat-conducting support serves as an intermediary component between the base plate and the core body. This mediator facilitates efficient heat transfer from the conductor through the core body to the base plate, reducing the temperature difference without requiring direct contact between all components, thus solving the thermal management problem while keeping the structure relatively simple

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If the conductor cross-section is reduced to lower costs, then material costs decrease, but the conductor cannot dissipate heat effectively, causing temperature limitations and derating

Engineering Contradiction:
Improveconductor material quantityVSAvoidthermal management capability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The heat dissipation function is extracted from the conductor itself and transferred to the dedicated heat-conducting support and base plate assembly. This allows the conductor to be optimized for electrical performance with reduced cross-section while the thermal management is handled by the support structure with high thermal conductivity materials, separating the electrical and thermal functions

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The heat-conducting support acts as an intermediary that compensates for the reduced heat dissipation capability of the thinner conductor. By providing an additional thermal pathway through the support and base plate, the system maintains effective heat removal even with less conductor material, preserving reliability while reducing material quantity

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If high thermal conductivity materials are used for the support, then heat dissipation improves, but the support may become electrically conductive, causing eddy current losses

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoideddy current losses
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The support structure exhibits local quality differentiation: it possesses high thermal conductivity for effective heat dissipation while maintaining electrical insulation properties in the regions where it contacts the base plate and core body. This is achieved by selecting materials and designing the support geometry such that thermal transfer is optimized at contact interfaces while electrical conductivity is minimized in the support body itself, preventing eddy current formation

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The support is made from composite or specialized materials that combine high thermal conductivity with electrical insulation properties. These composite materials enable the support to function as an efficient thermal pathway while blocking electrical current paths, thereby achieving both improved heat dissipation and prevention of eddy current losses simultaneously

Inventive Principle:
Principle #40Composite materials

4Strength

If the base assembly is designed to bear vehicle weight, then mechanical strength is sufficient, but heat conduction from the conductor to the base plate is impeded by the mechanical load structure

Engineering Contradiction:
Improveload-bearing capacityVSAvoidheat conduction efficiency
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The mechanical load-bearing function and thermal conduction function are segmented into different components: the base plate and support structure handle mechanical loads, while the heat-conducting support provides a dedicated thermal pathway. This segmentation allows the mechanical structure to be optimized for strength while the thermal structure is optimized for heat conduction, resolving the conflict between load-bearing capacity and heat conduction efficiency

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 solution enables higher charging power with the same conductor cross-section or smaller conductor size, maintains lower temperature differences, and increases mechanical load capacity, reducing the risk of component failure and derating, even in harsh conditions.

Implementation Method 1

a heat-conducting element is provided, which at least partially surrounds the pressure pedestal and connects the stranded wire carrier to the core body in a heat-transferring manner

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

The at least one support is designed as a heat-conducting element made of a material with a thermal conductivity of λ > 5 W/(m·K)

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 3

A primary coil is located in a ground assembly outside the motor vehicle, which inductively interacts with a secondary coil inside the motor vehicle to charge the energy storage device

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4434805A1Base assembly for an inductive charging device
Publication Date: 2024.09.25 MAHLE INT GMBH
  • EP4434805A1 patent drawingFigure 1~2
  • EP4434805A1 patent drawingFigure 3~4f
  • EP4434805A1 patent drawingFigure 5a~5c

AI summary

The present invention relates to a base assembly (1) for an inductive charging device (2), comprising a base plate (8), a flat coil (5) having a conductor (9), a core arrangement (10) for magnetic flux guidance having at least one core body (11), a lower cavity (14) being formed between the at least one core body (11) and the base plate (8), at least one support (15) being provided between the at least one core body (11) and the base plate (8), at least one support (15) being made of a material with a thermal conductivity of λ > 5 W/(m K), the flat coil (5) having a stranded wire carrier (12) having at least one pressure pedestal (20) on which the stranded wire carrier (12) rests on an associated core body (11), and a heat-conducting element (29) being provided.which at least partially surrounds the pressure platform (20) and connects the strand carrier (12) to the core body (11) in a heat-transferring manner.