Fuel Cell Stack Seal Member Segmentation and Nesting
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Solution Overview
Problem
Conventional fuel cell stacks have inadequate sealing properties, leading to potential leakage of reactive gases.
Innovation Solution
A fuel cell stack design featuring a casing with interposed seal members, including frame, extension, and connection seal portions, housed in grooves on the plates, and connected by liquid packing, which improves sealing by positioning the seal members accurately and reducing stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If seal members are interposed between plates to prevent gas leakage, then sealing properties are improved, but device complexity increases due to multiple seal components and grooves
Solution Approach 1:
The seal member is divided into multiple functional portions: a frame seal portion for sealing the outer periphery, extension seal portions for sealing plate mating surfaces, and connection seal portions for sealing gaps between extension portions. This segmentation allows each portion to address specific sealing needs, improving overall sealing reliability while maintaining manageable complexity through functional specialization.
Solution Approach 2:
The seal members are housed within grooves formed on the plates, creating a nested structure where the seal portions are contained within the plate geometry. This nesting approach integrates the sealing function into the existing plate structure, improving sealing reliability without adding significant external complexity to the casing assembly.
2Reliability
If multiple seal portions are used to improve sealing at different locations, then sealing properties are improved, but manufacturing complexity increases
Solution Approach 1:
The seal member is manufactured as an integrated component with distinct functional portions (frame seal, extension seal, connection seal) formed in a single piece. This segmentation of function without segmentation of manufacturing allows complex sealing geometries to be achieved through single-step molding or extrusion processes, improving sealing reliability while maintaining ease of manufacture.
Solution Approach 2:
Multiple seal portions that address different sealing locations are combined into a single integrated seal member component. This merging eliminates the need for separate manufacturing and assembly of multiple discrete seal parts, improving overall sealing reliability while simplifying the manufacturing process through single-component production.
3Reliability
If seal members are positioned at plate boundaries to prevent leakage, then sealing properties are improved, but stress concentrations increase at connection portions
Solution Approach 1:
The connection seal portions are designed to bridge gaps between extension seal portions before assembly, pre-positioning the seal material to distribute stresses evenly across the plate mating surfaces. This preliminary configuration of the seal geometry prevents stress concentration at connection points during operation, maintaining both sealing reliability and structural strength.
Solution Approach 2:
The cross-sectional geometry and material distribution of the connection seal portions are optimized to reduce stress concentrations. By adjusting the shape parameters and material properties of the connection portions, the design achieves both effective sealing at plate boundaries and reduced stress levels, maintaining durability while improving sealing reliability.
Data Source
AI summary
A fuel cell stack includes a casing which is formed by a combination of a plurality of plates; and a seal member interposed between the plurality of plates. The plurality of plates includes a pair of first plates facing each other in a first direction with the cell stacked body interposed therebetween, a pair of second plates facing each other in a second direction with the cell stacked body interposed therebetween, and a pair of third plates facing each other in a third direction with the cell stacked body interposed therebetween. The seal member has a frame seal which is formed in a frame shape extending to follow an outer circumferential portion of the first plate, an extension seal which extends in the first direction integrally with the frame seal, and a connection seal which is close to or in contact with the extension seals facing each other.