Fuel Cell Elastomer Film Seals for Uneven Bipolar Plates
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Solution Overview
Problem
Conventional fuel cell manufacturing processes face challenges in achieving adequate fluid mechanical sealing due to uneven bipolar plate geometries, limited material selection for elastomer layers, and high costs associated with fluorinated rubbers, which require lengthy drying and cross-linking times and are prone to quality assurance issues.
Innovation Solution
A fuel cell design featuring elastomer layers formed as films on a frame, providing both roughness compensation and elasticity, with a larger material selection including acrylate and fluorinated rubbers, and a method involving a roll-based process for faster application and reduced material usage, allowing for a more efficient and cost-effective production with simplified quality control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorinated rubbers are used for elastomer layers, then chemical stability and adhesion are improved, but drying and cross-linking time increases and cost increases
Solution Approach 1:
The patent changes the chemical composition parameters of the elastomer layer by using nitrile rubber (NBR) with specific acrylonitrile content (18-30%) instead of fluorinated rubbers. This parameter change maintains adequate adhesion properties while eliminating the need for lengthy drying and cross-linking processes, thus reducing production time without sacrificing bonding reliability.
Solution Approach 2:
The patent employs a cost-effective elastomer material (nitrile rubber) that does not require expensive post-processing treatments. By selecting a material that achieves adequate adhesion without extensive drying and cross-linking, the solution reduces both material cost and processing time, effectively replacing expensive, time-consuming materials with more economical alternatives.
2Ease of manufacture
If screen printing process is used for elastomer deposition, then material application is achieved, but quality assurance expense increases due to fault proneness
Solution Approach 1:
The patent replaces the screen printing process with a calendaring process, which is a mechanical rolling method. This substitution eliminates the fault-prone screen printing technique and provides more consistent, controllable elastomer layer application, thereby reducing quality assurance expenses while maintaining ease of manufacture.
Solution Approach 2:
The patent changes the manufacturing process parameters from screen printing to calendaring, where the elastomer layer is applied through controlled rolling between calibrated rollers. This parameter change provides precise control over layer thickness and uniformity, reducing defects and minimizing the need for expensive quality assurance testing.
3Reliability
If metallic bead with elastomer layer is used for sealing, then fluid mechanical sealing is achieved, but bead geometry unevenness reduces sealing effectiveness
Solution Approach 1:
The patent merges the sealing function and the roughness compensation function into a single elastomer layer applied directly to the frame. This integration eliminates the need for metallic beads with their inherent geometry unevenness, as the elastomer layer alone provides both sealing and adaptation to surface irregularities, thereby improving sealing reliability without being constrained by bead manufacturing precision.
Solution Approach 2:
The patent employs a thin elastomer layer (5-50 μm) that acts as a flexible sealing film. This flexible film can conform to the bipolar plate surface irregularities, providing effective sealing without requiring the rigid metallic bead structure. The flexibility of the thin film compensates for surface unevenness, maintaining sealing effectiveness independent of underlying substrate precision.
4Reliability
If seal height is increased to 0.2-0.7 mm for adequate sealing, then sealing capability is improved, but flow field height and gas diffusion layer thickness must be increased accordingly
Solution Approach 1:
The patent uses a thin elastomer film (5-50 μm) that provides effective sealing through its flexibility and ability to conform to surface irregularities. This thin film approach eliminates the need for increased seal height, allowing the flow field and gas diffusion layer to maintain their original optimized dimensions without requiring additional height to accommodate a taller seal structure.
Solution Approach 2:
The patent changes the sealing mechanism parameter from height-dependent mechanical sealing to material-property-dependent flexible sealing. By relying on the elastomer's inherent flexibility and adhesion properties rather than increased thickness, the solution achieves adequate sealing capability without increasing the overall height of the flow field or gas diffusion layer components.
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
The solution enables a more efficient and cost-effective fuel cell manufacturing process with improved sealing capabilities, reduced material costs, and simplified quality control, utilizing a wider range of elastomer materials and a more robust production method.
Implementation Method 1
the elastomer layers arranged on the frame are adapted to sealing off the bipolar plates fluid mechanically by way of roughness compensation and the provided elasticity
Data Source
AI summary
The disclosure relates to a fuel cell having a membrane electrode assembly installed in a cutout of a frame, a first bipolar plate arranged on a first side of the membrane electrode assembly and a second bipolar plate arranged on a second side of the membrane electrode assembly, the second side being opposite the first side. An edge region of the frame comprises a first elastomer layer on a first side of the edge region of the frame, the first side facing toward the first bipolar plate. The edge region of the frame further comprises a second elastomer layer on a second side of the edge region of the frame, the second side facing toward the second bipolar plate. The first and second elastomer layers are each formed as a film. The first and second elastomer layers are configured to fluidly seal the bipolar plates. A method for producing a fuel cell is also provided.