Solid Oxide Fuel Cell Substrate Gas Permeability Control
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Solution Overview
Problem
In solid oxide fuel cells, temperature distribution issues during power generation lead to excessive temperature increases at specific portions, potentially exceeding operation limits and reducing durability.
Innovation Solution
The cell substrate's gas permeability is strategically reduced in high-temperature areas, either through compression or notching, to decrease power generation in those regions, thereby lowering maximum temperatures and maintaining durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the porosity is increased at the downstream side of the unit cell to enhance power generation, then the power generation performance is improved, but the temperature of the unit cell increases excessively and may exceed the operation limit temperature
Solution Approach 1:
The patent applies local quality by creating different porosity regions within the cell substrate. Specifically, the downstream side (outlet side) is designed with lower porosity compared to the upstream side, allowing different regions to serve different functions: the upstream region with higher porosity enhances power generation, while the downstream region with lower porosity suppresses excessive temperature rise.
2Productivity
If the gas permeability is increased to improve fuel gas supply and power generation, then the power generation efficiency is enhanced, but the temperature distribution becomes uneven and maximum temperature increases
Solution Approach 1:
The patent implements local quality by varying the gas permeability of the cell substrate across different regions. The outlet side is designed with lower gas permeability to reduce power generation in high-temperature zones, thereby controlling the maximum temperature, while maintaining higher gas permeability in other regions to ensure adequate fuel gas supply and power generation efficiency.
3Ease of manufacture
If the porosity is made uniform across the cell substrate to simplify manufacturing, then the manufacturing process is simplified, but the temperature distribution becomes uneven leading to durability issues
Solution Approach 1:
The patent applies local quality by designing the cell substrate with spatially varying porosity and gas permeability properties. This allows the substrate to simultaneously achieve reasonable manufacturability while controlling temperature distribution to prevent durability issues. The gradient structure enables different regions to have optimized properties for their specific functional requirements.
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 approach effectively reduces the maximum temperature of the cell module, preventing damage and improving durability by ensuring a more uniform temperature distribution across the fuel cell.
Implementation Method 1
the gas permeability of the cell substrate in a portion corresponding with a portion of the cell module having a highest cell module temperature is lower than the gas permeability of the cell substrate in a portion corresponding with a portion of the cell module other than the portion having the highest cell module temperature
Data Source
Figure 1(a)~1(b)
Figure 2~3
Figure 4(a)~4(b)
AI summary
A cell module for a solid oxide fuel cell includes a cell substrate (1) having gas permeability, one electrode (2) among a fuel electrode and an air electrode formed on the cell substrate, a solid electrolyte (3) formed on the one electrode, and the other electrode (4) formed on the solid electrolyte, wherein in the case of counter-flow of the fuel gas and the oxidant gas flow, the gas permeability of a central portion (1b) of the cell substrate in the gas flow direction is lower than the gas permeability of an inlet portion (1a) and an outlet portion (1c) of the cell substrate.