SOFC Electrolyte Sheet Burr Height Control
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Solution Overview
Problem
Solid oxide fuel cells (SOFCs) with electrolyte sheets having burr heights of 100 µm or less on their peripheral portions are prone to cracking during electrode application and stacking, leading to rapid degradation of power generation performance.
Innovation Solution
An electrolyte sheet with a thickness of 50 to 300 µm, featuring a burr height of 100 µm or less in a first zone near the edge and a controlled ratio of burr heights in adjacent zones, produced using a method involving a green sheet producing step, pressing step with specific surface roughness and pressure distribution, and sintering step to minimize warping and stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the burr height is reduced to 100 μm or less on the electrolyte sheet, then the manufacturing precision is improved, but the reliability deteriorates due to cracking during electrode application and stacking
Solution Approach 1:
The invention applies different burr height control standards to different zones of the electrolyte sheet. The first zone (0-3mm from edge) requires burr height ≤100μm, while the ratio between third zone (0.61-3mm) and second zone (0-0.6mm) burr heights is controlled within 0.5-2.0. This localized quality control prevents cracking by ensuring gentle slope transitions at critical edge regions while maintaining overall manufacturing precision.
2Productivity
If the printing speed is increased to increase productivity, then the productivity is improved, but the reliability deteriorates due to cracking in the electrolyte sheet
Solution Approach 1:
The invention performs preliminary burr control by controlling the burr height in the first zone to be 100μm or less and controlling the ratio of burr heights between zones before electrode application. This preliminary action of surface preparation ensures that even when printing speed is increased for higher productivity, the electrolyte sheet maintains sufficient reliability and resistance to cracking during the high-speed printing process.
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 electrolyte sheet reduces the susceptibility to cracking and enhances the reliability of SOFC single cells, maintaining stable power generation performance by minimizing warping and stress at the peripheral edges.
Implementation Method 1
irradiating the principal surface of the sheet with a laser beam at a pitch of 0.01 mm and three-dimensionally analyzing light reflected from the principal surface using a laser optical three-dimensional shape measurement device
Implementation Method 2
a pressing step of sandwiching the green sheet between plates whose surfaces facing surfaces of the green sheet each have an arithmetical mean roughness value (Ra) of 0.001 to 0.1 μm and a dry peel force of 10 to 1000 mN/cm and applying a pressure to the green sheet
Implementation Method 3
a sintering step of sintering the green sheet that has undergone the pressing step
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
In at least one of principal surfaces of the electrolyte sheet for a solid oxide fuel cell of the present invention, (1) a burr height [ΔH (0-3)] in a first zone is 100 µm or less, as measured by irradiating the principal surface of the sheet with a laser beam at a pitch of 0.01 mm using a laser optical three-dimensional shape measurement device, the first zone being a zone extending between a peripheral edge of the sheet and a position 3 mm inside the peripheral edge, and (2) a ratio [ΔH (0.61-3) / ΔH (0-0.6)] of a burr height [ΔH (0.61-3)] in a third zone to a burr height [ΔH (0-0.6)] in a second zone is 0.5 or more and 2.0 or less, as calculated from the burr heights measured by irradiating the principal surface of the sheet with a laser beam at a pitch of 0.01 mm using the laser optical three-dimensional shape measurement device, the second zone being a zone extending between the peripheral edge of the sheet and a position 0.6 mm inside the peripheral edge, and the third zone being a zone extending between a position 0.61 mm inside the peripheral edge of the sheet and the position 3 mm inside the peripheral edge.