Thermoelectric Conversion Element with Insulator Layer and Thickness Ratio
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Solution Overview
Problem
Thermoelectric conversion elements with N-type and P-type portions experience stress and reduced power generation efficiency due to differences in thermal expansion coefficients and resistance values, leading to cracking and decreased performance, especially when exposed to corrosive gases.
Innovation Solution
A thermoelectric conversion element with a laminated structure where N-type and P-type portions are directly bonded with an insulator layer, and electrodes formed using NiCr, NiCu, and Ag, with a thickness ratio of N-type to P-type portions between 4 and 11, alleviating stress and improving resistance matching for enhanced efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the P-type thermoelectric conversion portion is covered with an insulating layer to prevent corrosion, then corrosion resistance is improved, but thermal stress increases due to different thermal expansion coefficients between N-type and P-type portions
Solution Approach 1:
The patent applies preliminary action by forming the insulating layer selectively only in regions where the P-type thermoelectric conversion portion is exposed to corrosive gases, rather than covering the entire surface. This preliminary protective measure prevents corrosion at critical locations while minimizing the addition of materials that could cause thermal stress. The insulating layer is formed before final assembly, allowing precise control over coverage areas.
Solution Approach 2:
The patent implements local quality by applying the insulating layer selectively to specific regions where the P-type thermoelectric conversion portion is exposed to corrosive environments, rather than uniformly covering all surfaces. This localized approach provides corrosion protection exactly where needed while minimizing the overall volume of insulating material, thereby reducing thermal stress accumulation. The selective coverage is achieved through controlled formation processes that target only the exposed peripheral regions.
2Ease of manufacture
If the thickness ratio of N-type to P-type thermoelectric conversion portions is not controlled, then manufacturing is simplified, but crack generation increases due to stress concentration
Solution Approach 1:
The patent applies parameter changes by establishing a specific thickness ratio range (4 to 11) between N-type and P-type thermoelectric conversion portions. This controlled parameter relationship balances the thermal expansion characteristics of the two material types, preventing stress concentration that would lead to cracking. The thickness ratio serves as a critical design parameter that reconciles manufacturing feasibility with structural integrity, ensuring uniform stress distribution during thermal cycling.
3Ease of manufacture
If the resistance values of P-type and N-type thermoelectric conversion portions are mismatched, then material selection is easier, but power generation efficiency decreases
Solution Approach 1:
The patent implements parameter changes by controlling the thickness of thermoelectric conversion portions to achieve optimal resistance matching between P-type and N-type materials. By adjusting the thickness parameter within the specified ratio range, the overall resistance of each type can be tuned to match, maximizing power generation efficiency. This parameter-based approach allows standard material selection while achieving optimal electrical characteristics through dimensional control.
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 reduces crack generation and increases power generation efficiency by matching resistance values and alleviating thermal stress, while maintaining corrosion resistance and simplifying the manufacturing process.
Implementation Method 1
a thermoelectric conversion element in which a plurality of N-type thermoelectric conversion portions and a plurality of P-type thermoelectric conversion portions are alternately arranged
Data Source
AI summary
A thermoelectric conversion element that includes a laminated body having a plurality of first thermoelectric conversion portions, a plurality of second thermoelectric conversion portions, and an insulator layer. The first thermoelectric conversion portions and the second thermoelectric conversion portions are alternately arranged in a Y-axis direction and bonded to each other in first regions, and the insulator layer is interposed between the first thermoelectric conversion portions and the second thermoelectric conversion portions in second regions. The insulator layer surrounds a periphery of each of the second thermoelectric conversion portions. A ratio (W2/W1) of a thickness (W2) of the first thermoelectric conversion portion to a thickness (W1) of the second thermoelectric conversion portion in the Y-axis direction is greater than 4 and 11 or less.