Solid Oxide Fuel Cell Stack Body Inspection via Shrinkage Rate
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Solution Overview
Problem
Existing methods for inspecting solid oxide fuel cell stack bodies are complex, time-consuming, and economically inefficient, as they require high voltage applications and extensive facilities, and fail to accurately assess current-voltage characteristics and structural density, potentially degrading the stack body during inspection.
Innovation Solution
A method and apparatus that measure the length, area, or volume of the stack body before and after firing, calculate the shrinkage rate and signal-to-noise (S/N) ratio, and determine the acceptability of these parameters to assess power generation capability, using a simple and economical process that does not burden the stack body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high DC voltage is applied to inspect through pores in insulative ceramics sheet, then detection capability is improved, but process complexity and time increase
Solution Approach 1:
The patent extracts and measures specific geometric parameters (length, area, volume) of the stack body separately, then calculates shrinkage rate through mathematical computation rather than directly measuring through pores with complex high voltage equipment. This simplifies the inspection process while maintaining detection accuracy.
Solution Approach 2:
The patent replaces the electrical measurement system (high DC voltage application) with a geometric measurement system. By measuring physical dimensions before and after firing and calculating shrinkage rate, the method substitutes complex electrical inspection with simpler dimensional measurement and computation.
2Measurement precision
If high DC voltage is applied to inspect through pores, then detection capability is improved, but inspection time increases
Solution Approach 1:
The patent performs measurements before firing (green state) and after firing, capturing all necessary dimensional data in advance. The shrinkage rate is then calculated from these pre-collected measurements, eliminating the need for time-consuming during-process inspections and reducing total inspection time.
3Measurement precision
If high DC voltage is applied to inspect stack body, then detection capability is improved, but stack body degradation occurs
Solution Approach 1:
The patent replaces the harmful electrical field (high DC voltage) with a non-intrusive geometric measurement approach. By measuring external dimensions and calculating shrinkage rate, the method avoids applying high voltage to the stack body, thereby preventing degradation while maintaining detection capability.
4Measurement precision
If complex inspection facilities are used to inspect stack body, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent uses simple, inexpensive measurement tools (calipers, rulers, or basic dimensional measurement devices) instead of expensive specialized inspection facilities. The method relies on straightforward geometric measurements and mathematical calculation, making the inspection process economical while maintaining adequate precision for quality control.
Data Source
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AI summary
A method of inspecting a stack body (50) of at least a porous layer and a dense layer comprises the first step of measuring the length of the stack body (50) before the stack body (50) is fired, the second step of measuring the length of the stack body (50) after the stack body (50) is fired, the third step of calculating a shrinkage rate of the stack body (50) based on a first measured value from the first step and a second measured value from the second step, the fourth step of determining whether the calculated shrinkage rate of the stack body (50) is acceptable or not based on the calculated shrinkage rate, the fifth step of calculating an S/N ratio of the stack body (50) based on the first measured value and the second measured value, and the sixth step of determining whether the current-voltage characteristics of the stack body (50) are acceptable or not based on the calculated S/N ratio.