Ordered Resin Shell Thermal Conductivity in Insulating Composites

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Solution Overview

Problem

Conventional electrical insulation materials, such as epoxy resins, exhibit both excellent electrical insulation and thermal insulation properties, which is undesirable for air-cooled electrical equipment as it reduces efficiency and durability, and existing solutions fail to provide effective heat dissipation without compromising mechanical and electrical performance.

Innovation Solution

The development of high thermal conductivity (HTC) organic-inorganic hybrid materials with nano-to-micro sized inorganic fillers that form an ordered resin shell around HTC materials, reducing phonon scattering and enhancing thermal conductivity while maintaining electrical insulation properties, by using surface-treated particles and sol-gel chemistry to create continuous pathways for phonon transport.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrical insulation materials (epoxy resins, mica flake, glass fiber) are used, then excellent electrical insulation properties are achieved, but thermal insulation properties are also improved (which is undesirable as it reduces heat dissipation efficiency)

Engineering Contradiction:
Improveelectrical insulation propertiesVSAvoidheat dissipation efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent uses composite materials by combining epoxy resin with inorganic fillers (such as aluminum oxide, aluminum nitride, boron nitride, or silicon carbide particles) to create a hybrid material system. This composite structure allows the material to simultaneously maintain electrical insulation properties from the resin while introducing high thermal conductivity pathways through the inorganic filler network, thereby resolving the contradiction between electrical insulation and heat dissipation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by creating regions of high thermal conductivity within the insulating material. The inorganic fillers are distributed throughout the epoxy resin matrix, creating localized thermal conduction pathways while the overall material maintains its electrical insulation properties. This allows different regions of the material to have different functional characteristics - electrical insulation from the resin and thermal conduction from the filler regions.

Inventive Principle:
Principle #3Local quality

2Reliability

If multiple layers of mica tape are wrapped around coils to provide high voltage insulation, then electrical insulation is improved, but the complexity of the insulation system and difficulty of heat dissipation increase

Engineering Contradiction:
Improveelectrical insulationVSAvoidinsulation system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into a single material system. Instead of using separate layers for electrical insulation and thermal management, the modified epoxy resin composite simultaneously provides both electrical insulation and enhanced thermal conduction in one integrated material, thereby reducing the number of components and simplifying the overall insulation system architecture.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal material that performs multiple functions: electrical insulation, thermal conduction, and mechanical bonding. The epoxy resin matrix provides electrical insulation and adhesion, while the incorporated inorganic fillers provide thermal conduction pathways, allowing a single material to fulfill multiple roles that traditionally required separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of energy

If inorganic fillers are added to resin to improve thermal conductivity, then heat dissipation is enhanced, but phonon scattering at interfaces may reduce the effectiveness

Engineering Contradiction:
Improvethermal conductionVSAvoidphonon scattering
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by carefully controlling the size, shape, and distribution parameters of the inorganic filler particles. By optimizing these parameters, the patent minimizes phonon scattering effects while maximizing thermal conduction. The specific particle size range and surface treatment parameters are adjusted to reduce interface resistance and phonon scattering, thereby enhancing the overall thermal conductivity of the composite material.

Inventive Principle:
Principle #35Parameter changes

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

The solution achieves higher thermal conductivity than conventional insulating materials, enabling effective heat dissipation without compromising electrical insulation, mechanical strength, or voltage endurance, making it suitable for both high and low voltage electrical equipment.

Implementation Method 1

facilitates the transport of phonons through a high thermal conductivity (HTC) impregnated medium to reduce the mean distances between the HTC materials below that of the mean phonon path length. This reduces the phonon scattering and produces a greater net flow or flux of phonons away from the heat source

Methodology Applied
Scientific EffectPhonon transport:

Implementation Method 2

This reduces the phonon scattering and produces a greater net flow or flux of phonons away from the heat source

Methodology Applied
Scientific EffectPhonon scattering:

Implementation Method 3

The HTC materials impart a degree of ordering on the surrounding resin structure. This creates an ordered resin shell (ORS) around the HTC materials. The ORSs created in this manner can be manipulated through HTC concentration and clustering to create overlapping areas of ORSs that reduce the scattering of phonons passing through them

Methodology Applied
Scientific EffectOrdered resin shell formation:

Data Source

PatentEP2069429B1NANO and meso shell-core control of physical properties and performance of electrically insulating composites
Publication Date: 2015.05.27 SIEMENS ENERGY INC
  • EP2069429B1 patent drawingFigure 1
  • EP2069429B1 patent drawingFigure 2
  • EP2069429B1 patent drawingFigure 3

AI summary

A high thermal conductivity resin that is made up of a host resin matrix (42) and high thermal conductivity fillers (30) that are mixed within the host resin to form a resin mixture. The fillers comprise at least 3-5% by weight of the resin mixture, and the fillers are from an average of 1 -100 nm in at least one dimension, and where the particles are smaller than an average of 1000 nm in the particles' longest dimension. The host resin matrix forms an ordered resin shell (40) around the high thermal conductivity fillers (30), whereby resin molecules are aligned perpendicular to the surface of the high thermal conductivity fillers. An overlap of the ordered resin shells (44) is formed between the high thermal conductivity fillers such that continuous pathways for ordered resin shells are created through the resin mixture.