Fuel Cell Stack Seal Rib Alignment for Stable Gas Sealing
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Solution Overview
Problem
Existing fuel cell seals using elastic materials like rubber are unstable and prone to misalignment and plastic deformation, leading to inadequate gas sealing between unit cells.
Innovation Solution
A fuel cell stack design featuring a seal sheet with a protruding portion on one separator and a recessed portion on the other, allowing for improved alignment and sealing performance through a crimped structure that applies a low load without causing plastic deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fitting structure made of elastic sealing material such as rubber is used, then sealing function is achieved through compression and deformation, but the fitting structure becomes unstable and causes misalignment
Solution Approach 1:
The invention changes the physical state of the sealing structure from elastic/deformable to rigid/non-deformable by using a rigid sealing plate instead of elastic rubber material. The rigid structure maintains dimensional stability and prevents misalignment while still achieving sealing through the rigid recessed-protruding fitting structure.
Solution Approach 2:
The invention uses a composite sealing structure combining a rigid sealing plate with rigid recessed-protruding features on the separators. This composite approach integrates the sealing function with the structural components, eliminating the need for separate elastic sealing materials while maintaining both sealing effectiveness and alignment precision.
2Reliability
If high fastening load is applied to the seal line to ensure sealing, then sealing performance is improved, but the seal line rib structure undergoes plastic deformation
Solution Approach 1:
The invention changes the mechanical properties of the sealing structure from flexible to rigid, allowing sealing to be achieved without excessive compression loads that would cause plastic deformation. The rigid sealing plate maintains its shape and sealing contact without deforming the separator rib structure.
Solution Approach 2:
The sealing function is segmented from the flexible rubber material and integrated into a rigid sealing plate that works in conjunction with the rigid recessed-protruding structure on the separators. This segmentation allows the sealing load to be distributed and controlled without causing localized plastic deformation.
3Adaptability or versatility
If elastic sealing material is used to accommodate misalignment, then sealing flexibility is improved, but the fitting structure becomes insufficiently stable
Solution Approach 1:
The invention changes the stability parameter of the sealing structure by using rigid materials with high dimensional stability instead of elastic materials that deform. The rigid sealing plate and rigid recessed-protruding structure provide stable, repeatable fitting without the instability caused by elastic deformation.
Data Source
AI summary
A fuel cell stack includes a cell stack in which a plurality of unit cells each including a pair of separators is stacked together. The fuel cell stack includes a seal sheet configured to seal between adjacent unit cells. The pair of separators each include a seal line rib on a seal sheet side of the separator, the seal line rib serving as a seal line with the seal sheet. Among two facing separators that are a first facing separator and a second facing separator facing each other while sandwiching the seal sheet between the adjacent unit cells, the first facing separator includes a protruding portion on at least one part of the seal line rib, and the second facing separator includes a recessed portion in the seal line rib that is configured to fit the protruding portion.