Magnesium Thermoelectric Material Gradient Junction
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Solution Overview
Problem
Thermoelectric conversion elements with multilayer structures face issues of peeling and cracking due to thermal expansion differences between junction layers and thermoelectric materials, and have complex structures requiring electrodes at interfaces for electricity extraction.
Innovation Solution
A magnesium-based thermoelectric conversion material with a first layer of Mg2Si and a second layer of Mg2SixSn1-x, directly joined with a tin concentration transition region, where the tin concentration increases away from the junction surface, reducing thermal expansion differences and eliminating the need for electrodes between layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a multilayer structure with conductive junction layer is used to improve thermoelectric conversion efficiency across temperature distribution, then thermoelectric conversion efficiency is improved, but peeling occurs due to thermal expansion difference between junction layer and thermoelectric conversion materials
Solution Approach 1:
The patent introduces a gradient structure at the junction between layers with different thermal expansion coefficients. This gradient structure acts as an intermediary that gradually transitions between the two materials, reducing the abrupt thermal expansion difference and preventing peeling while maintaining the multilayer configuration for improved thermoelectric conversion efficiency.
Solution Approach 2:
The patent changes the composition parameter gradually across the junction interface by creating a gradient structure. This parameter change approach allows for a smooth transition in thermal expansion properties between layers, eliminating the sudden property change that causes peeling while preserving the beneficial thermoelectric properties of each layer.
2Ease of operation
If electrodes are disposed at interfaces between different thermoelectric conversion materials to extract electricity, then electricity extraction is enabled, but structure complexity increases
Solution Approach 1:
The patent merges the functions of the conductive junction layer and the electrode into a single integrated structure. The gradient structure itself serves as both the connection between different thermoelectric materials and the electrical conduction path, eliminating the need for separate electrodes at each interface and significantly reducing structural complexity.
Solution Approach 2:
The gradient junction structure performs multiple functions simultaneously: it provides thermal conduction, electrical conduction, mechanical bonding, and gradual property transition. This multi-functionality eliminates the need for separate specialized components like interface electrodes, simplifying the overall device structure while maintaining electricity extraction capability.
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 configuration enhances thermoelectric conversion efficiency by maximizing thermoelectric characteristics in different temperature ranges while preventing peeling and cracking, and simplifies the structure by eliminating the need for electrodes between layers.
Implementation Method 1
A thermoelectric conversion element is an electronic element which can carry out interconversion between heat and electricity, known as the Seebeck effect or the Peltier effect. The Seebeck effect is an effect of converting heat energy into electric energy.
Implementation Method 2
due to the difference in a coefficient of thermal expansion between the junction layer and the thermoelectric conversion materials, peeling easily occurs in the junction portion
Data Source
AI summary
A magnesium-based thermoelectric conversion material includes a first layer formed of Mg2Si and a second layer formed of Mg2SixSn1-x (here, x is equal to or greater than 0 and less than 1), in which the first layer and the second layer are directly joined to each other, and within a junction surface with the first layer and in the vicinity of the junction surface, the second layer has a tin concentration transition region in which a tin concentration increases as a distance from the junction surface increases. The junction layer is regarded as a site in which a tin concentration is found to be equal to or lower than a detection limit by the measurement performed using EDX.