Fuel Cell Seal with Integrated Flow Barriers
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Solution Overview
Problem
In fuel cells, bypass paths around the seal space between bipolar plates and the membrane electrode assembly lead to significant gas flow bypass, reducing stability, increasing sensitivity at low stoichiometric ratios, and affecting water management and operating conditions.
Innovation Solution
A seal design featuring flow barriers integrated with the seal body, positioned to reduce the hydraulic cross-section of bypass paths, manufactured as a single piece using liquid injection molding, which are independent of the seal compression to prevent hydraulic blockage and maintain seal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seal is compressed to reduce bypass flow, then the seal effectiveness improves, but the seal deformation and potential hydraulic blockage increases
Solution Approach 1:
The seal is divided into functionally distinct segments: the seal body for compression and sealing, and separate flow barriers positioned at a distance to reduce bypass flow without directly contacting the seal during compression. This segmentation allows each component to perform its specific function independently, preventing hydraulic blockage while maintaining seal effectiveness.
Solution Approach 2:
The flow barriers act as intermediary elements that mediate between the seal body and the bypass path. Positioned at a controlled distance from the seal body, they reduce bypass flow through their geometric configuration without interfering with the seal compression process, thus preventing hydraulic blockage while maintaining sealing effectiveness.
2Quantity of substance
If flow barriers are positioned close to the seal body to reduce bypass flow, then the hydraulic cross section decreases, but the seal compression and expansion is impeded
Solution Approach 1:
The flow barriers are positioned in a different spatial dimension relative to the seal body, specifically at a controlled distance away rather than directly adjacent. This dimensional separation allows the flow barriers to effectively reduce bypass flow in the flow path direction while not impeding the seal compression in the perpendicular direction.
3Quantity of substance
If multiple flow barriers are added to reduce bypass flow, then the hydraulic cross section is reduced more effectively, but the device complexity increases
Solution Approach 1:
Multiple flow barriers are merged into a single integrated seal component manufactured as one piece using liquid injection molding. This combining approach reduces the number of separate parts and assembly steps, thereby reducing device complexity while still achieving effective bypass flow reduction through the collective action of multiple flow barrier elements.
Solution Approach 2:
The flow barriers utilize geometric parameter changes in their cross-sectional shape and positioning to achieve flow reduction. By optimizing the cross-sectional area and positioning of the flow barriers, effective bypass flow reduction is achieved without requiring complex structures, maintaining simplicity through parameter optimization rather than structural complexity.
Data Source
AI summary
A seal (34) for a fuel cell (10), which includes multiple bipolar plates (13) and at least one membrane electrode assembly (12), the seal (34) having a seal body (40) surrounding a free inner chamber (42) is provided. It is provided that at least two flow barriers (46) pointing into the inner chamber (42) are formed as a single piece with the seal body (40), the flow barriers (46) being situated at a distance from the seal body (40) by at least one connecting element (48).