Fuel Cell Stack Bonding Pattern Mitigates Drum Deformation
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Solution Overview
Problem
Fuel cell stacks face issues with excessive deformation in a drum-like shape due to the thickness of gas diffusion layers, leading to sealing performance deterioration and potential cracking, which existing techniques attempt to address with elastic members like rubber, increasing manufacturing costs and complexity.
Innovation Solution
A cell module design featuring a frame with strategically positioned adhesive bonding areas between separators and a frame, allowing for bowing and bending to mitigate drum-like deformation, using either a first or second bonding pattern where bonding areas do not overlap, and separators made of composite materials for flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If gas diffusion layers are designed with relatively large thickness, then the structural integrity and electrochemical performance are improved, but the cell module deforms excessively in a drum-like shape causing sealing performance deterioration and cracking
Solution Approach 1:
The bonding area between the gasket and separator is segmented into a first bonding area and a second bonding area that are positioned at different locations. This segmentation allows different regions to serve different functions: one region provides sealing while the other accommodates deformation, thereby resolving the contradiction between maintaining shape integrity and allowing necessary deformation
Solution Approach 2:
Different regions of the gasket bonding area are assigned different qualities/functions. The first bonding area is designed for secure sealing attachment, while the second bonding area is positioned to accommodate local deformation. This local differentiation allows the gasket to maintain sealing performance in critical areas while allowing deformation in non-critical areas
2Reliability
If elastic members like rubber are used as sealing members to improve followability of deformation, then the sealing performance is improved, but the manufacturing time increases due to long molding time under high temperature
Solution Approach 1:
The invention changes the material parameter from elastic rubber to a non-elastic gasket material. This parameter change eliminates the need for long high-temperature molding processes while maintaining sealing performance through the strategic bonding pattern design, thereby resolving the contradiction between sealing reliability and manufacturing time
3Reliability
If thick rubber is used as the sealing member to improve sealing performance, then the followability of deformation is improved, but the cell module configuration becomes soft causing deviation from designed location or twist during stacking
Solution Approach 1:
The gasket is designed with localized bonding areas rather than uniform thick rubber construction. This allows specific regions to provide sealing force while other regions maintain structural rigidity, preventing overall softness and position deviation during stacking while maintaining sealing performance at critical interfaces
4Reliability
If the gasket is bonded to the separator around the outer periphery of the electrode body, then the sealing is improved, but the interval between adjacent separators is limited by the stretch of the gasket
Solution Approach 1:
The bonding area is segmented into multiple discrete regions rather than a continuous peripheral bond. This segmentation provides localized sealing at critical areas while leaving other areas free to adjust, thereby maintaining sealing performance while enabling adaptability in separator interval adjustment
Data Source
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AI summary
With regard to at least one unit cell out of a plurality of unit cells, when the at least one unit cell is viewed along a stacking direction of the plurality of unit cells, at least one bonding area out of first to third bonding areas is formed at a position that does not overlap with another bonding area.