Fuel Cell Housing U-Shaped Plates Thermal Stress
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Solution Overview
Problem
The existing fuel cell apparatuses face challenges in assembling components due to interference between the stack and ceiling walls, leading to increased stress on welded portions and reduced durability and longevity due to thermal expansion and contraction.
Innovation Solution
A fuel cell apparatus design featuring U-shaped plate members with upwardly opening surfaces and thermal insulating layers, where the cathode and exhaust gas flow passages are formed by these members, allowing for easier assembly and reducing stress on welded portions by absorbing thermal deformation through flexible intersection points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the housing is formed by assembling inverted-U-shaped members with ceiling walls, then the housing provides complete enclosure and structural integrity, but the assembly parts interfere with the ceiling walls making assembly difficult and time-consuming
Solution Approach 1:
The patent removes the ceiling wall component from the inverted-U-shaped members, extracting the problematic element that caused assembly interference. The housing is formed by U-shaped plate members without ceiling walls, allowing assembly parts to be installed without obstruction while maintaining structural integrity through alternative design configurations.
Solution Approach 2:
The housing is segmented into multiple U-shaped plate members layered in the thickness direction, with clearance provided between them. This segmentation allows each member to be independently positioned and assembled, facilitating easier assembly of internal components while maintaining the overall structural integrity of the housing.
2Volume of moving object
If the ceiling walls are positioned close to the stack, then the housing compactness is improved, but thermal expansion and contraction cause stress loading on welded portions reducing durability
Solution Approach 1:
The ceiling walls are completely removed from the housing structure, eliminating the source of thermal expansion stress that affected welded portions. Without ceiling walls connecting the upper ends of side walls, there are no rigid structures to transmit thermal stress to welding joints, thereby preserving welded portion durability while maintaining housing compactness through the layered U-shaped member configuration.
Solution Approach 2:
The housing employs a flexible configuration where U-shaped plate members are layered with clearance between them, allowing the structure to accommodate thermal expansion and contraction without generating stress. This flexible arrangement replaces rigid ceiling wall connections, enabling the housing to adapt to temperature changes while maintaining structural integrity.
3Object-affected harmful factors
If ceiling walls are added to complete the housing enclosure, then the housing provides full coverage and thermal insulation, but the thermal deformation affects welded portions through side walls
Solution Approach 1:
The ceiling walls are extracted from the housing design, removing the structural element that transmitted thermal deformation to welded portions. The housing achieves thermal insulation through the layered U-shaped plate member configuration and clearance spaces, which provide thermal barriers without creating rigid stress transmission paths to welding joints.
Solution Approach 2:
The design anticipates thermal expansion and contraction by providing clearance between layered U-shaped plate members, creating space for dimensional changes without stress transmission. This beforehand cushioning prevents thermal deformation from affecting welded portions, as the clearance absorbs expansion movements before they can propagate to welding joints.
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
Enhances assembly performance, reduces stress on welded areas, and improves durability and longevity by mitigating the effects of thermal expansion and contraction on the housing.
Implementation Method 1
the first ceiling wall 213X of the first inverted-U-shaped member 210X and the second ceiling wall 223X of the second inverted-U-shaped member 220X, both of which constitute the housing 200X, are likely to thermally expand and to undergo extensional deformation or elongation deformation
Implementation Method 2
the first ceiling wall 213X and the second ceiling wall 223X repeat the thermal expansion and a thermal contraction as a power generating operation is performed and stopped, respectively
Implementation Method 3
a cathode gas of the cathode flow passage is pre-heated by the exhaust gas flowing through the exhaust gas flow passage
Data Source
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AI summary
A fuel cell apparatus includes a housing (200) including a power generation chamber (203) and a closing member (201, 202), a stack (400), a cathode gas flow passage (500), and an exhaust gas flow passage (600), the housing includes a first U-shaped plate member (210) which includes a first upper surface opening portion (211) opening upwardly, two first side walls (212) and a first bottom wall (213), the housing includes a second U-shaped plate member (220) which includes a second upper surface opening portion (221) opening upwardly, two second side walls (222) and a second bottom wall (223), the housing is formed by layering the first and second U-shaped plate members with each other while a clearance being provided therebetween, and one of the cathode gas flow passage and the exhaust gas flow passage includes a side clearance flow passage (510, 610) and a bottom clearance flow passage (520, 620).