Thermoelectric Conversion Element Ionization Potential Control

Solution Overview

Problem

Thermoelectric conversion elements with carbon nanotubes exhibit poor durability and significant variation in power generation capacity, especially when stored in high-temperature environments, and require improved performance and manufacturing yield.

Innovation Solution

A thermoelectric conversion element is developed with a p-type layer containing nanocarbon materials and specific onium or inorganic salts, and an n-type layer with onium salts, where the ionization potential difference between the layers is adjusted to be within 0.15 eV or less, optimizing power generation capacity and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If carbon nanotubes with onium salts are used to create n-type thermoelectric conversion layers, then the thermoelectric conversion performance is improved, but the durability in high-temperature environments deteriorates

Engineering Contradiction:

Improvepower generation capacityVSAvoiddurability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the ionization potential difference between p-type and n-type layers to be 0.15 eV or less. This specific parameter adjustment optimizes the thermoelectric conversion performance while improving durability. The ionization potential of the n-type layer is controlled to be within 0.05 eV of the p-type layer through selective use of onium salts with specific ionization potentials, resolving the contradiction between power generation capacity and durability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining carbon nanotubes with specific onium salts (such as tetrabutylammonium hydroxide, tetraoctylammonium hydroxide, or methyltrioctylammonium chloride) to create the n-type thermoelectric conversion layer. This composite structure maintains high power generation capacity while improving stability and durability in high-temperature environments compared to using carbon nanotubes alone or with conventional dopants.

Inventive Principle:

Principle #40Composite materials

2Power

If carbon nanotubes with onium salts are used to create n-type thermoelectric conversion layers, then the thermoelectric conversion performance is improved, but the variation in power generation capacity among manufactured elements increases

Engineering Contradiction:

Improvepower generation capacityVSAvoidvariation in power generation capacity

Core Design Contradiction:

PowerVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by precisely controlling the ionization potential difference between p-type and n-type layers to be 0.15 eV or less. This specific parameter adjustment optimizes the thermoelectric conversion performance while improving durability. The ionization potential of the n-type layer is controlled to be within 0.05 eV of the p-type layer through selective use of onium salts with specific ionization potentials, resolving the contradiction between power generation capacity and durability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining carbon nanotubes with specific onium salts (such as tetrabutylammonium hydroxide, tetraoctylammonium hydroxide, or methyltrioctylammonium chloride) to create the n-type thermoelectric conversion layer. This composite structure maintains high power generation capacity while improving stability and durability in high-temperature environments compared to using carbon nanotubes alone or with conventional dopants.

Inventive Principle:

Principle #40Composite materials

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 excellent power generation capacity and durability with reduced variation among thermoelectric conversion elements, enhancing their performance and manufacturing consistency.

Implementation Method 1

Thermoelectric conversion elements can convert thermal energy directly into electric power

Methodology Applied

Scientific EffectSeebeck effect: Seebeck Effect

Implementation Method 2

a technique of preparing an n-type thermoelectric conversion layer by reducing CNT by using an onium salt having a specific structure as a dopant

Methodology Applied

Scientific EffectChemical reduction: Reduction

Data Source

PatentUS10991868B2Thermoelectric conversion element

Publication Date: 2021.04.27 FUJIFILM CORP

AI summary

An object of the present invention is to provide a thermoelectric conversion element which includes a p-type thermoelectric conversion layer and an n-type thermoelectric conversion layer, has excellent power generation capacity and durability, and inhibits a variation in power generation capacity between lots.The thermoelectric conversion element of the present invention is a thermoelectric conversion element having a p-type thermoelectric conversion layer and an n-type thermoelectric conversion layer electrically connected to the p-type thermoelectric conversion layer, in which the p-type thermoelectric conversion layer contains a nanocarbon material and at least one kind of component selected from the group consisting of an onium salt and an inorganic salt, the n-type thermoelectric conversion layer contains a nanocarbon material and an onium salt, and a difference between an ionization potential of the p-type thermoelectric conversion layer and an ionization potential of the n-type thermoelectric conversion layer is equal to or smaller than 0.15 eV.