Frameless SOFC Stack With Hollow Fasteners for Sealing and Weight Reduction
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Solution Overview
Problem
Conventional solid oxide fuel cell (SOFC) stacks are heavy, brittle, and require external frames, leading to mechanical and chemical compatibility issues, which limits their application in lightweight devices like drones and electric vehicles, and they suffer from sealing problems due to adhesive use in metal-supported SOFCs.
Innovation Solution
A frameless SOFC stack design utilizing hollow fasteners that extend through the cells themselves, providing gas flow channels for improved distribution and eliminating the need for external frames and adhesives, thereby reducing weight and thickness while maintaining strength and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional thick ceramic anode supports are used in SOFCs, then mechanical strength is improved, but weight increases significantly
Solution Approach 1:
The patent changes the material parameter from thick ceramic to thin metal-supported structure, fundamentally altering the physical properties to achieve both strength and lightness. The metal support provides sufficient mechanical strength while being significantly lighter than ceramic alternatives.
Solution Approach 2:
The patent employs composite material structure combining metal support with ceramic electrolyte and electrode layers. This composite approach leverages the strength and lightness of metal while maintaining the electrochemical functionality of ceramic-based SOFCs.
2Strength
If external frames are used to hold multiple fuel cells together, then structural strength is improved, but overall weight and dimensions increase
Solution Approach 1:
The patent merges the fastening function with the bipolar plate structure itself. The bipolar plate incorporates integrated fastening features that eliminate the need for separate external frames, thereby reducing overall weight and dimensional complexity while maintaining structural integrity.
Solution Approach 2:
The bipolar plate serves multiple functions simultaneously: it acts as an electrical conductor, a structural support, and an integrated fastening element. This multi-functionality eliminates the need for dedicated external framing components.
3Reliability
If adhesives are used for stacking electrolyte and anode on metal bipolar plates, then sealing is improved, but sealing issues arise due to chemical compatibility
Solution Approach 1:
The patent removes adhesives from the stacking process entirely. Instead, it employs mechanical interlocking features and precise tolerances to achieve both sealing and structural attachment, thereby eliminating chemical compatibility issues between adhesives and metal bipolar plates.
Solution Approach 2:
The patent introduces precision-machined mating surfaces and mechanical interlocking features as intermediaries to achieve sealing. These mechanical features mediate the connection between components, replacing chemical bonding with physical engagement that avoids adhesive-related compatibility problems.
Data Source
AI summary
A fuel cell stack is provided that includes a top end plate, a bottom end plate, a plurality of fuel cells provided between the top end plate and the bottom end plate, at least one bipolar plate, a plurality of hollow fasteners, and a plurality of sleeves. Each of the at least one bipolar plate is formed between two of the plurality of fuel cells. The plurality of hollow fasteners and the plurality of sleeves extend through holes in each of the top end plate, the bottom end plate, the plurality of fuel cells and the at least one bipolar plate. Each of the plurality of sleeves surrounds one of the plurality of hollow fasteners. Each of the plurality of hollow fasteners comprises a top surface, a hole in the top surface, a side surface, and a plurality of holes formed in the side surface.