Thermoelectric Conversion Element Using Doped Graphite Charge Transport Layer
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Solution Overview
Problem
Conventional thermoelectric conversion elements face challenges in achieving high output due to high internal resistance and difficulty in securing a large temperature difference between electrodes, particularly in sheet-type elements where the thickness of the thermoelectric conversion material layer is thin and the distance between electrodes is long, and in balancing high Seebeck coefficient, electric conductivity, and low thermal conductivity.
Innovation Solution
The use of a charge transport layer made of graphite doped with charge-donating or charge-accepting materials to create n-type or p-type semiconductor properties, combined with thermoelectric conversion material layers such as carbon nanotubes or Bi-Te based compounds, and the formation of thermoelectric conversion modules with insulating substrates having varying thermal conductivity to optimize electric conductivity and thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the thickness of the thermoelectric conversion material layer is made thin and the distance between electrodes is made long in sheet-type elements, then the element can avoid direct radiant heat from the heat source and secure a temperature difference between electrodes, but the internal resistance of the thermoelectric conversion material layer becomes high and large output cannot be obtained
Solution Approach 1:
The invention divides the thermoelectric conversion element into multiple independent thermoelectric conversion units arranged in an array. Each unit has its own pair of electrodes and thermoelectric conversion material layer. By segmenting the element, the patent can optimize each unit's dimensions independently - making the material layers thin to avoid radiant heat while maintaining adequate electrical conductivity within each unit, and arranging multiple units in parallel to achieve high overall output without the internal resistance penalty of a single large thin layer
Solution Approach 2:
The invention transitions from a conventional single-layer thick structure to a multi-layer array structure where thermoelectric conversion units are arranged in the plane dimension rather than relying on a single thick layer in the thickness dimension. This dimensional reorganization allows thin material layers (good for avoiding radiant heat) to be combined in large numbers (good for maintaining low internal resistance and high output), effectively decoupling the conflicting requirements through spatial arrangement
2Temperature
If conventional block-shaped thermoelectric conversion elements are used, then the structure is simple, but radiation heat from the heat source directly affects the low-temperature electrode and it is difficult to ensure the temperature difference between electrodes
Solution Approach 1:
The invention replaces the conventional block-shaped structure (where heat must travel through the thickness of the block) with a sheet-type array structure where thermoelectric conversion units are arranged in the plane. This dimensional change allows the low-temperature electrodes to be positioned far from the heat source in the plane direction, effectively blocking direct radiant heat paths while maintaining structural simplicity through the use of flexible sheets and simple array assembly
Solution Approach 2:
The invention uses flexible insulating sheets as the substrate for arranging thermoelectric conversion units. These thin film structures allow the element to be configured in various geometries and enable the electrodes to be positioned optimally for heat management. The flexibility of thin films permits creating structures that naturally block radiant heat paths while maintaining electrical and thermal performance
3Power
If materials with high electric conductivity are used to improve internal resistance, then the internal resistance decreases, but the Seebeck coefficient decreases and large output cannot be obtained
Solution Approach 1:
By segmenting the thermoelectric conversion element into multiple independent units, the patent can use materials optimized for high Seebeck coefficient in each unit without requiring extremely high electric conductivity. The overall low internal resistance is achieved through the parallel arrangement of multiple units, which effectively reduces the total resistance while allowing each unit to use materials with optimal Seebeck coefficients for maximum output
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 approach significantly reduces internal resistance, allows for a larger temperature difference between electrodes, and enables the use of materials with high Seebeck coefficients, resulting in a thermoelectric conversion element with enhanced output performance and stability.
Implementation Method 1
a charge transport layer, a thermoelectric conversion material layer and electrodes, wherein the charge transport layer comprises graphite treated to dope charge-donating materials so that the graphite has an n-type semiconductor property, or graphite treated to dope charge-accepting materials so that the graphite has a p-type semiconductor property
Implementation Method 2
power generation elements using the Seebeck effect (thermoelectric conversion power generation elements)
Implementation Method 3
cooling/heating elements using the Peltier effect (Peltier elements)
Data Source
AI summary
The present invention provides thermoelectric conversion elements and thermoelectric conversion modules which are possible to effectively use oxide materials having high Seebeck coefficient, and excellently improve their outputs. The present invention provides thermoelectric conversion elements which comprise at least a charge transport layer, thermoelectric conversion material layers and electrodes, wherein the charge transport layer comprises a graphite treated to dope charge-donating materials so that the graphite has an n-type semiconductor property, or a graphite treated to dope charge-accepting materials so that the graphite has a p-type semiconductor property, and provides thermoelectric conversion modules using the thermoelectric conversion elements.