Vanadium Dioxide Composite Heat Storage With Higher Thermal Conductivity

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Solution Overview

Problem

Conventional solid heat storage materials face challenges with low thermal conductivity and inadequate temperature suppression, limiting effective heat dissipation and storage capabilities.

Innovation Solution

A solid heat storage material is developed by bonding vanadium dioxide with highly thermally conductive substances like copper, silver, aluminum, or carbon materials, ensuring dense and close adhesion without reaction phases, and adjusting the phase transition temperature through doping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If vanadium dioxide is used as a solid heat storage material, then latent heat storage performance is improved, but thermal conductivity is insufficient

Engineering Contradiction:
Improvelatent heat storage densityVSAvoidthermal conductivity
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The patent combines vanadium dioxide with highly thermally conductive substances (copper, silver, aluminum, or carbon materials) to create a composite heat storage material. This composite structure allows the material to simultaneously achieve high latent heat storage density from vanadium dioxide and high thermal conductivity from the conductive additives, resolving the contradiction between these two properties.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by dispersing highly thermally conductive substances specifically within the vanadium dioxide matrix at controlled concentrations (1-50 wt%). This localized enhancement of thermal conductivity in specific regions allows the material to maintain its latent heat storage properties while improving heat dissipation capabilities where needed.

Inventive Principle:
Principle #3Local quality

2Temperature

If thermal conductivity of vanadium dioxide is increased by adding highly thermally conductive substances, then heat dissipation performance is improved, but material complexity increases

Engineering Contradiction:
Improveheat dissipation performanceVSAvoidmaterial composition complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent employs parameter changes by systematically varying the concentration of highly thermally conductive substances (1-50 wt%) and controlling particle size (0.1-10 μm) to optimize the balance between thermal conductivity enhancement and material simplicity. This allows tuning the material properties to achieve desired heat dissipation performance without excessive complexity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses local quality by dispersing thermal conductive additives at the micro-scale within the vanadium dioxide matrix, creating a heterogeneous structure where thermal conductivity is enhanced locally without requiring complex macro-structures or multiple distinct phases.

Inventive Principle:
Principle #3Local quality

3Device complexity

If vanadium dioxide is used without modification, then material simplicity is maintained, but temperature suppression capability is inadequate

Engineering Contradiction:
Improvematerial structure simplicityVSAvoidtemperature suppression capability
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The patent creates a composite material combining vanadium dioxide with simple, readily available highly thermally conductive substances (copper, silver, aluminum, or carbon materials). This approach maintains relative material simplicity while dramatically improving temperature suppression capability through the synergistic effect of the composite components.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent adopts the successful phase transition mechanism of vanadium dioxide (metal-insulator transition) and enhances it by adding thermal conductive substances, effectively copying and improving upon the original material's temperature suppression mechanism rather than creating an entirely new approach.

Inventive Principle:
Principle #26Copying

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 material achieves enhanced thermal conductivity and effective latent heat storage, suppressing excessive temperature rises and enabling wide-range heat dissipation and storage adjustments.

Implementation Method 1

In recent years, developed has been a solid heat storage material employing solid-solid phase transition (Patent Literature 3). The material described in Patent Literature 3 has electronic phase transition as the origin of latent heat and thus keeps its shape before and after phase transition without fusion.

Methodology Applied
Scientific EffectSolid-solid phase transition: Phase Change

Implementation Method 2

utilization of latent heat has been examined (Patent Literature 1 and Patent Literature 2). Many conventional latent heat storage materials employ the heat of fusion due to the phase change from a solid to a liquid

Methodology Applied
Scientific EffectLatent heat storage: Latent Heat

Implementation Method 3

thermal conduction as an important factor in heat exchange has not been sufficiently examined. For example, the thermal conductivity of paraffin as a representative heat storage material is approximately 0.2 W/mK, which is too low for prompt heat dissipation/heat absorption.

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4151696B1Solid heat storage material having regulated thermal conductivity and composite
Publication Date: 2025.11.19 NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE & TECHNOLOGY
  • EP4151696B1 patent drawingFigure 1
  • EP4151696B1 patent drawingFigure 2
  • EP4151696B1 patent drawingFigure 3

AI summary

A solid heat storage material includes a bonding of vanadium dioxide and a highly thermally conductive substance higher in thermal conductivity than the vanadium dioxide, the highly thermally conductive substance being dispersed in the vanadium dioxide, the vanadium dioxide and the highly thermally conductive substance adhering closely and densely together, the highly thermally conductive substance having a volume fraction of 0.03 or more.