Hemmed Fuel Cell Stack Enclosure Design
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Solution Overview
Problem
Conventional fuel cell stack compression retention enclosures are bulky, heavy, and require complex assembly processes due to large bolted joints, which increase assembly time and costs, and struggle to accommodate membrane swelling and compressive stress relaxation effectively.
Innovation Solution
A compression retention enclosure using interlocking hem joints and C-link members to maintain compressive force on the fuel cell stack, reducing the number of components and weight, while allowing for membrane swelling accommodation and environmental sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional bolted joints are used in compression retention enclosure, then structural strength is ensured, but weight and device complexity increase
Solution Approach 1:
The patent merges the compression shell and side sheets into a unified enclosure structure where the side sheets are hemmed to the compression shells, eliminating the need for separate bolted joints. This integration reduces the number of components and overall weight while maintaining structural integrity through the hemmed connections.
2Strength
If conventional bolted joints are used in compression retention enclosure, then structural strength is ensured, but assembly time and manufacturing complexity increase
Solution Approach 1:
The side sheets are hemmed directly to the compression shells to form an integrated enclosure, eliminating the need for separate bolted connections. This reduces assembly steps and manufacturing complexity while maintaining structural strength.
Solution Approach 2:
The side sheets are pre-hemmed to the compression shells during manufacturing, creating ready-to-assemble components that require minimal field assembly. This preliminary preparation significantly reduces assembly time and complexity.
3Force
If rigid end plates and tie rods are used to maintain compression, then compressive force is maintained, but device complexity and volume increase
Solution Approach 1:
The compression shells and side sheets are merged into a single integrated enclosure structure that maintains compressive force on the fuel cell stack. This eliminates the need for separate tie rods and complex multi-component assembly, reducing device complexity while preserving the necessary compressive force.
4Force
If conventional bolted joints are used, then compression retention is achieved, but weight and assembly complexity increase
Solution Approach 1:
The enclosure is designed as an integrated structure where side sheets are hemmed to compression shells, reducing the number of discrete components and eliminating complex bolted joints. This simplification maintains compression retention capability while reducing overall device complexity.
Data Source
AI summary
A fuel cell system is provided which includes a compression retention enclosure with upper and lower compression shells and side sheet components coupled by interlocking hem joints. Methods for manufacturing compression retention enclosures with hem joints such that the enclosure remains sealed upon operational swelling of the fuel stack are also provided. A compression shell may be formed from a light weight composite structure having a polymeric layer interposed between steel skins, and an extension of the top steel skin may form a hemmed edge or may form a side sheet having a hemmed edge. Side sheet panels may be coupled to the end plates by interlocking two opposing hemmed edges to form the hem joint, or by sliding an opposing C-linking element between two hemmed edges held under compression force in an interlocking position.