Coated Subgasket for Fuel Cell Sealing and Deformation Control
Solution Overview
Problem
Fuel cell subgaskets degrade or deform under rigorous conditions of high temperature and pressure, affecting the life and performance of polymer electrolyte membrane fuel cells, as they either compress excessively with thick subgaskets or deflect with thin subgaskets, leading to reduced fuel cell efficiency.
Innovation Solution
The implementation of fuel-cell membrane-subgasket assemblies with a coated subgasket that includes a subgasket body made from materials like poly(ethylene terephthalate) (PET) coated with metals, steels, or ceramics, which enhances mechanical properties and resistance to water intrusion, thereby reducing degradation and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thick subgaskets are used, then sealing capability is improved, but subgasket compression and deformation increase
Solution Approach 1:
The subgasket is constructed as a composite structure combining a porous PTFE layer and a non-porous PTFE layer, each providing different functional properties. The porous layer provides compliance and sealing while the non-porous layer provides structural support and resistance to compression deformation, resolving the contradiction between sealing capability and shape stability.
Solution Approach 2:
Different regions of the subgasket have different properties - the porous PTFE layer provides local compliance for sealing contact, while the non-porous PTFE layer provides local structural rigidity to resist compression. This local differentiation allows the subgasket to simultaneously achieve good sealing and maintain shape under compression.
2Shape
If thin subgaskets are used, then subgasket deflection by reactant gas flow is reduced, but compression resistance deteriorates
Solution Approach 1:
The composite structure of porous and non-porous PTFE layers creates a subgasket that is thin enough to resist deflection from gas flow while the non-porous layer provides sufficient compression resistance. The layered composite architecture optimizes both shape stability and compression strength without requiring increased thickness.
3Ease of manufacture
If polymeric sheet material is used for subgasket, then ease of manufacture is improved, but resistance to degradation under high temperature and pressure deteriorates
Solution Approach 1:
The subgasket combines PTFE material known for its exceptional temperature and pressure resistance with a layered porous/non-porous structure. This composite construction maintains ease of manufacture through standard bonding processes while dramatically improving resistance to thermal and pressure degradation compared to conventional polymeric materials.
Data Source
AI summary
Fuel-cell membrane-subgasket assemblies may include an electrolyte membrane and a coated subgasket overlying the electrolyte membrane around a perimeter of the electrolyte membrane so as to define an active area inside the perimeter. The coated subgasket may comprise a subgasket body formed from a subgasket material. At least one side of the coated subgasket includes a subgasket coating layer containing or formed from a coating material such as metals, ceramics, polymers, polymer composites, or other hard coatings. Fuel-cell assemblies may include gas diffusion media, a bipolar plate, and a fuel-cell membrane-subgasket assembly having a coated subgasket. Fuel-cell stacks may include clamping plates, unipolar endplates, and a plurality of individual fuel-cell assemblies, at least one of which includes a fuel-cell membrane-subgasket assembly having a coated subgasket.