Thermoelectric Conversion Element with Insulated Electrodes
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Solution Overview
Problem
Miniaturization of thermoelectric conversion elements is hindered by galvanic cell formation during etching, leading to material dissolution and abnormal etching of electrodes, due to potential differences between the thermoelectric conversion material layer and the electrodes.
Innovation Solution
A thermoelectric conversion element design featuring a substrate with a thermoelectric conversion layer covered by an insulating layer, where the first electrode is formed with a first layer connecting to the thermoelectric conversion layer through a contact hole and a second electrode is formed from a different material with a work function, ensuring the first layer is not exposed to the etching solution, preventing galvanic cell formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the spacing between the first electrode and the second electrode is narrowed to increase short-circuit current, then the thermoelectric conversion element can be miniaturized, but galvanic cell formation occurs during etching leading to material dissolution and abnormal etching of electrodes
Solution Approach 1:
An insulating layer is introduced as an intermediary between the thermoelectric conversion material layer and the electrodes. This insulating layer prevents direct contact between the thermoelectric material and electrode materials during etching, thereby eliminating galvanic cell formation while allowing the electrodes to be positioned close together for miniaturization.
Solution Approach 2:
The structure is segmented into distinct layers: the thermoelectric conversion material layer, the insulating layer, and the electrode layers. This segmentation allows each layer to perform its specific function independently, with the insulating layer protecting the thermoelectric material from galvanic corrosion during electrode fabrication.
2Power
If different materials with different work functions are used for the first electrode and second electrode to enhance thermoelectric performance, then the thermoelectric conversion efficiency is improved, but galvanic cell formation occurs due to potential difference between the thermoelectric conversion material layer and the electrodes
Solution Approach 1:
The insulating layer acts as a mediator that electrically isolates the thermoelectric conversion material from the electrodes during the etching process. This prevents the formation of galvanic cells that would otherwise occur due to the potential difference between different materials, while still allowing the different work function materials to be used for optimized thermoelectric performance.
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 design allows for the miniaturization of thermoelectric conversion elements without damaging the thermoelectric conversion layer or electrodes, enhancing the selection of electrode materials based on work function without considering galvanic effects, thereby increasing short-circuit current.
Implementation Method 1
thermoelectric conversion elements are known that generate thermoelectromotive force between two electrodes due to temperature differences
Implementation Method 2
an insulating layer covering the thermoelectric conversion layer
Data Source
AI summary
A thermoelectric conversion element includes a substrate, a thermoelectric conversion layer disposed on a first main surface of the substrate, an insulating layer covering the thermoelectric conversion layer, a first electrode disposed on the insulating layer and connecting to a first main surface of the thermoelectric conversion layer via a first contact hole of insulating layer, and a second electrode disposed on the insulating layer and connecting to the first main surface of the thermoelectric conversion layer via a second contact hole of the insulating layer. At least a portion of the first electrode is formed from a material that has a work function that is different from a work function of a material forming the second electrode.