Fuel Cell Stack Seal Frame Reducing Polar Plate Load
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Solution Overview
Problem
The existing methods for manufacturing fuel cell stacks face challenges such as high plastic waste, poor utilization of catalyst-coated membranes, and difficulty in handling and assembling components due to flexible edges, especially when using injection molding for sealing, which is not compatible with thin polar plates required for high power density applications.
Innovation Solution
An assembly comprising a polar plate with a frame integrally connected to it, where the seal is applied to the frame rather than directly on the polar plate, allowing for a depression to house the membrane-electrode assembly, ensuring correct positioning and easy assembly, and using a plastic film frame with a different material for the seal, such as silicone or EPDM, to facilitate a circumferential seal and reduce load on the polar plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the seal is injection-molded directly onto the polar plate, then the seal is securely attached, but the thin polar plate is subjected to high loads requiring thicker plates and complex molds
Solution Approach 1:
The patent introduces a frame as an intermediary component between the seal and the polar plate. The seal is injection-molded onto the frame, which then attaches to the polar plate. This mediator absorbs the injection molding loads, protecting the thin polar plate while maintaining secure seal attachment.
Solution Approach 2:
The patent divides the sealing assembly into separate components: the frame and the seal. The seal is separately injection-molded onto the frame, and this assembled unit is then attached to the polar plate. This segmentation allows the injection molding process to be performed on the frame rather than directly on the thin polar plate, reducing complexity and load.
2Strength
If the seal is injection-molded onto the membrane electrode assembly, then the assembly is flexible and absorbs loads, but the resulting components are difficult to handle and assemble
Solution Approach 1:
The frame serves as a rigid intermediary that carries the injection-molded seal. This combination provides the load absorption capability of flexible materials while maintaining the handling and assembly ease of rigid structured components.
3Strength
If a frame is used to carry the seal, then the polar plate is protected from high loads, but additional components increase assembly complexity
Solution Approach 1:
The patent merges the frame and seal into a single integrated component through injection molding. The seal is molded directly onto the frame, creating one piece that attaches to the polar plate. This reduces the number of separate components and simplifies assembly while still protecting the polar plate from loads.
4Loss of substance
If flush-cut membrane electrode assemblies are used, then material utilization is improved, but flexible edges complicate positioning during assembly
Solution Approach 1:
The patent utilizes the flexibility of the membrane electrode assembly edges by having them arranged in a recess of the polar plate. The flexible edges conform to the recess geometry, providing self-positioning during assembly without requiring additional rigid support structures.
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 simplifies the manufacturing and assembly of fuel cell stacks by enabling series production of thin polar plates with high membrane-electrode assembly utilization, preventing voltage peaks, and ensuring a circumferential seal, thus making the assembly process more efficient and cost-effective.
Implementation Method 1
The seal can be injection-molded onto a frame of the membrane electrode assembly
Implementation Method 2
The membrane electrode assembly is fixed to the polar plate and/or the frame
Data Source
Figure 1
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AI summary
The invention relates to an assembly (10) for a fuel cell stack (100), comprising a polar plate (12) and a frame (13) which is cohesively connected to the polar plate (12), wherein the frame (13) has, on a side which is averted from the polar plate (12), at least one seal (14) which is connected to the frame (13). The invention further relates to a fuel cell stack (100) comprising the assembly (10) and to a method for producing the assembly (10).