Non-metallic Heat Spreaders and PCM for WPT Ferrite Thermal Management

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Solution Overview

Problem

Wireless power transfer pads face challenges in heat management due to core loss in ferrite structures, which leads to inefficient heat dissipation and potential damage from hot spots, especially when embedded in solid materials like concrete.

Innovation Solution

Incorporating non-metallic heat spreaders and a phase change material (PCM) within a trough, encased in a solid material, to effectively transfer heat from the ferrite structure to the PCM, maintaining the temperature within an optimal range that minimizes core loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If wireless power transfer transmits a large amount of power to minimize charging time, then power transfer efficiency is improved, but heat generation in the ferrite structure increases

Engineering Contradiction:

Improvepower transfer efficiencyVSAvoidheat generation

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent utilizes phase change material (PCM) that transitions from solid to liquid phase at a specific temperature range (20-40°C). The PCM absorbs excess heat from the ferrite structure during the phase transition, maintaining the ferrite temperature within the optimal range for high-power wireless power transfer operations.

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The patent introduces non-metallic heat spreaders as intermediary components between the ferrite structure and the PCM. These heat spreaders conduct heat from the ferrite core to the PCM, enabling efficient thermal coupling without creating eddy currents that would occur with metallic heat spreaders.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If heat is dissipated from the ferrite structure, then temperature control is improved, but core loss increases due to eddy currents in metallic heat spreaders

Engineering Contradiction:

Improvetemperature controlVSAvoidcore loss

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the material parameter of the heat spreaders from metallic to non-metallic materials. This parameter change eliminates the eddy current effect while maintaining thermal conduction capability, thereby reducing core loss while still achieving effective heat dissipation.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If the ferrite structure is embedded in solid material, then structural stability is improved, but heat dissipation becomes inefficient

Engineering Contradiction:

Improvestructural stabilityVSAvoidheat dissipation efficiency

Core Design Contradiction:

Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The patent segments the heat management system into distinct functional components: the ferrite structure, non-metallic heat spreaders, PCM, and encapsulating solid material. This segmentation allows each component to perform its specific function optimally - the solid material provides structural stability while the PCM and heat spreaders handle heat dissipation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent merges multiple functions into a unified encapsulated structure. The solid encapsulating material simultaneously provides structural stability, thermal coupling between components, and protection for the internal heat management system, while the PCM and heat spreaders handle the heat dissipation function.

Inventive Principle:

Principle #5Merging (Combining)

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 enhances heat dissipation and reduces core loss, preventing damage from hot spots and ensuring safe operation by maintaining the ferrite structure within a temperature range that minimizes core loss, thus improving the efficiency and safety of wireless power transfer systems.

Implementation Method 1

a phase change material ('PCM') in the trough where at least a portion of the heat spreaders extend into the PCM

Methodology Applied

Scientific EffectPhase change: Phase Change

Implementation Method 2

The PCM includes a phase change temperature between a solid state and a liquid state of the PCM that is within an optimal temperature range of the component of the ferrite structure

Methodology Applied

Scientific EffectLatent heat: Latent Heat

Implementation Method 3

each of the plurality of heat spreaders comprises a material that transfers heat from the component of the ferrite structure to the PCM

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11521780B2Static heat exchanger for wireless power transfer pad

Publication Date: 2022.12.06 UTAH STATE UNIVERSITY

AI summary

An apparatus for a wireless power transfer (“WPT”) pad heat management system includes a ferrite structure positioned adjacent to a coil configured to wirelessly transfer power. The apparatus includes a plurality of heat spreaders positioned along a length of a component of the ferrite structure. Each of the plurality of heat spreaders is non-metallic. The apparatus includes a trough shaped to surround at least a portion of each of the plurality of heat spreaders, wherein the trough is non-metallic. The apparatus includes a phase change material (“PCM”) in the trough where at least a portion of the heat spreaders extend into the PCM. The ferrite structure, coil, plurality of heat spreaders, trough and PCM are encased in a solid material, and each of the plurality of heat spreaders comprises a material that transfers heat from the component of the ferrite structure to the PCM.