Fuel Cell Stack Sealing Ribs to Limit Compression Set
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Solution Overview
Problem
The use of pressure-sensitive adhesive sheets as seals between fuel cells in a fuel cell stack leads to permanent deformation over time, compromising the seal due to compression set, which can result in damage during unfastening or displacement.
Innovation Solution
Incorporating ribs outside the sealing range of the inter-cell sealing material, with specific compressibility ranges to limit excessive deformation, and ribs inside the sealing range to further regulate compression, thereby maintaining seal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a pressure-sensitive adhesive sheet is used as a seal between fuel cells, then the fuel cells can be easily assembled and sealed, but the adhesive sheet undergoes permanent deformation over time due to compression set, compromising the seal integrity
Solution Approach 1:
The patent introduces ribs with specific compressibility characteristics (20%-70% compressibility) at localized positions within the sealing range. These ribs create zones of controlled compression that distribute the fastening load, preventing excessive compression in any single area. This localized structural modification allows the seal to maintain its integrity over time while preserving the ease of assembly provided by the pressure-sensitive adhesive sheet.
2Ease of operation
If the inter-cell sealing material is highly compressible, then it can conform well to fuel cell surfaces during assembly, but it undergoes excessive permanent deformation over time, leading to seal damage
Solution Approach 1:
The patent modifies the compressibility parameter of the sealing material by introducing ribs with controlled compressibility (20%-70% of the original sealing material thickness). This creates a gradient structure where the ribs provide initial conformability during assembly but limit the maximum compression to prevent excessive permanent deformation. The ribs act as mechanical stops that maintain the seal within an optimal compression range.
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
Reduces the maximum amount of permanent deformation of the inter-cell sealing material, ensuring consistent seal performance and preventing damage from excessive compression.
Implementation Method 1
the pressure-sensitive adhesive sheet is compressed by a fastening load
Implementation Method 2
the adhesive sheet undergoes permanent deformation (compression set) in the thickness direction over time
Data Source
AI summary
A fuel cell stack includes a plurality of fuel cells and an inter-cell sealing material disposed between the fuel cells. The fuel cells include a rib protruding in a direction of adjacent fuel cells. The rib is located outside the sealing range of the inter-sealing material. The rib has such a height that the compressibility of the inter-cell sealing material is 20% or more and 70% or less in the sealing range.