Thermoelectric conversion material, and thermoelectric conversion device, thermochemical battery and thermoelectric sensor having said material

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Solution Overview

Problem

Conventional alloy-based thermoelectric conversion materials have high thermal conductivity and low Seebeck coefficient, limiting their efficiency in converting waste heat into electric power.

Innovation Solution

Incorporating a capture compound, such as cyclodextrin, into the electrolyte of a thermo-electrochemical cell that selectively captures one redox pair component at low temperature and releases it at high temperature, thereby enhancing the Seebeck coefficient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional alloy-based thermoelectric conversion materials are used, then the device structure is simple and manufacturing is easy, but the thermal conductivity is high and Seebeck coefficient is low, resulting in poor conversion efficiency

Engineering Contradiction:
Improveease of manufactureVSAvoidconversion efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent uses a composite system combining a redox couple (iodide/triiodide ions) with a capture compound (cyclodextrin) in an electrolyte solution. This composite approach allows the system to achieve high Seebeck coefficient (up to 2000 µV/K) by utilizing both the electrochemical properties of the redox couple and the selective binding properties of cyclodextrin, while maintaining low thermal conductivity compared to solid alloy materials.

Inventive Principle:
Principle #40Composite materials

2Loss of energy

If thermo-electrochemical cells with redox couples are used, then the Seebeck coefficient is one order of magnitude larger than solid alloys, but the device complexity increases and manufacturing becomes more difficult

Engineering Contradiction:
ImproveSeebeck coefficientVSAvoiddevice complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent introduces cyclodextrin as an intermediary substance that selectively captures triiodide ions. This intermediary component enables the system to achieve high Seebeck coefficient by mediating the interaction between the redox couple and the electrolyte, while the cyclodextrin molecules can be simply dissolved in the electrolyte solution, avoiding complex device structures.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of energy

If cyclodextrin is added to capture triiodide ions selectively at low temperature and release at high temperature, then the Seebeck coefficient increases significantly, but the device structure becomes more complex

Engineering Contradiction:
ImproveSeebeck coefficientVSAvoiddevice complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent utilizes parameter changes in the cyclodextrin-triiodide binding system, where the binding constant changes with temperature. At low temperatures, cyclodextrin selectively captures triiodide ions, while at high temperatures, the binding weakens and triiodide is released. This temperature-dependent parameter change enables high Seebeck coefficient without requiring complex device structures, as the cyclodextrin simply needs to be dissolved in the electrolyte.

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 addition of cyclodextrin improves the Seebeck coefficient from 0.2 mV/K to up to 2000 µV/K, significantly enhancing the thermoelectric conversion efficiency.

Implementation Method 1

a host molecule or an aggregate formed by self-assembly of capture compounds... capable of capturing a target into the capture compound

Methodology Applied
Scientific EffectInclusion complex formation: Absorption (physical)

Implementation Method 2

capable of capturing only one of the redox pair selectively at a low temperature and can release it at a high temperature

Methodology Applied
Scientific EffectTemperature-dependent binding:

Implementation Method 3

In order to convert minute energy such as waste heat into electric power, a thermoelectric conversion material has attracted attention

Methodology Applied
Scientific EffectSeebeck effect: Seebeck Effect

Implementation Method 4

thermo-electrochemical cells, which are one type of thermoelectric conversion materials using a solution of ions capable of oxidation and reduction

Methodology Applied
Scientific EffectRedox reactions: Redox Reactions

Data Source

PatentEP3428984B1Thermoelectric conversion material, and thermoelectric conversion device, thermochemical battery and thermoelectric sensor having said material
Publication Date: 2025.02.19 THE JAPAN SCI & TECH AGENCY
  • EP3428984B1 patent drawingFigure 1~2
  • EP3428984B1 patent drawingFigure 3
  • EP3428984B1 patent drawingFigure 4

AI summary

The present invention provides a thermoelectric conversion material having a considerably increased Seebeck coefficient, and a thermoelectric conversion device, a thermo-electrochemical cell and a thermoelectric sensor which include the material. The thermoelectric conversion material of the present invention includes a redox pair and a capture compound which captures only one of the redox pair selectively at low temperature and releases at high temperature.