Fuel Cell Stack Structure for Thin Electrolyte Stress Relief
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Solution Overview
Problem
Fuel cells with thin electrolyte layers face mechanical strength issues, leading to breakage during stack assembly due to compression stress, as existing techniques do not adequately address stress application on the electrolyte layer.
Innovation Solution
A fuel cell design featuring an electrolyte layer sandwiched between anode and cathode electrodes, supported by an intermediate substrate, where the electrolyte layer's width is limited to the maximum width of the hollow portion between the substrate and the cell, preventing stress application during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electrolyte layer is made thinner to improve output density, then the output of the fuel battery cell is improved, but the mechanical strength becomes lower, so that breakage, such as a crack, is likely to be caused
Solution Approach 1:
The patent introduces a hollow portion between the first member and second member that acts as a cushioning space. This hollow portion is positioned to receive and absorb compression stress applied during stack assembling, preventing the stress from being transmitted to the thin electrolyte layer. The cushioning effect allows the electrolyte layer to be made thin for high output density while maintaining mechanical integrity during assembly.
2Productivity
If the electrolyte layer is made to be a thin film of 1 μm or less to obtain high output density, then the output density is improved, but the electrolyte can be broken by the compression stress during stack assembling
Solution Approach 1:
The patent introduces an intermediate substrate as a mediator between the compression stress application points and the electrolyte layer. This intermediate substrate, positioned at the outer peripheral portion, serves as a buffer that decouples the compression stress from the electrolyte layer, allowing the thin electrolyte film to maintain its integrity while still achieving high output density.
Solution Approach 2:
The hollow portion is designed beforehand to accommodate and cushion the compression stress that will be applied during stack assembling. This pre-designed cushioning space prevents stress transmission to the electrolyte layer before the actual compression occurs, ensuring reliability during the assembly process.
3Reliability
If compression stress is applied from the up and down sides by screw fastening to improve sealability and reduce contact electric resistance, then the sealability is improved, but stress is applied to the cell, which may cause electrolyte breakage
Solution Approach 1:
The patent extracts or removes the harmful compression stress from the path to the electrolyte layer by introducing a hollow portion and intermediate substrate. These structures create a mechanical decoupling that allows compression stress to be applied for sealability improvement while preventing stress transmission to the electrolyte layer, thus avoiding breakage.
Data Source
AI summary
An object of the present invention is to provide a fuel cell that obtains high output density and prevents stress application to the cell during stack assembling and breakage. The fuel cell is equipped with a unit cell including a structure in which an electrolyte layer is sandwiched between an anode electrode layer and a cathode electrode layer. The unit cell is disposed between a first member and a second member. An intermediate substrate is disposed between the first member and the second member. The unit cell is supported at the outer peripheral portion thereof by the intermediate substrate. The width of the electrolyte layer is the maximum width or less of a hollow portion formed between at least one of the first member and the second member and the unit cell.