Fuel Cell Porous Separator Aperture Design for Stress Reduction
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Solution Overview
Problem
The existing porous separators for fuel cells cause stress concentration and destruction of the gas diffusion layer and membrane electrode assembly due to uneven surface pressure and structural design, leading to reduced diffusivity and durability.
Innovation Solution
A porous separator with modified passage apertures featuring a protruding portion on the inside surface that reduces stress concentration by being in surface contact with the gas diffusion layer or membrane electrode assembly, alleviating structural destruction and improving diffusivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional flow field structures with channels and lands are used, then manufacturing cost and weight are reduced, but stress concentration occurs around the lands leading to destruction of gas diffusion layer and membrane electrode assembly
Solution Approach 1:
The patent applies porous materials by forming passage apertures with protruding portions inside the flow field plate. The protruding portions create a porous-like structure that distributes surface pressure uniformly across the gas diffusion layer, preventing stress concentration and destruction while maintaining the structural integrity and low cost of the flow field plate.
2Reliability
If fine pore structures such as metal/carbon foam or wire mesh are inserted into reaction surface, then gas diffusion layer is uniformly compressed and surface pressure is distributed, but manufacturing cost increases and weight and volume increase
Solution Approach 1:
The patent merges the flow field plate structure with the pressure distribution function by integrating passage apertures with protruding portions directly into the flow field plate. This eliminates the need for separate fine pore structures like metal or carbon foam, achieving uniform surface pressure distribution while maintaining manufacturing simplicity and reducing cost.
3Productivity
If passage apertures are formed in inclined surfaces of flow field plate, then fuel diffusion is improved, but flow resistance increases under high current conditions
Solution Approach 1:
The patent applies local quality by forming passage apertures with protruding portions at specific locations within the flow field plate. The protruding portions are strategically positioned to enhance fuel diffusion into the reaction surface while controlling flow resistance. This localized modification optimizes fuel distribution without creating excessive flow resistance under high current conditions.
Data Source
AI summary
A porous separator for a fuel cell is provided and features the shape of a passage aperture formed in a flow field plate. The modified shape of the passage aperture minimizes destruction of a gas diffusion layer or a membrane electrode assembly attributable to stress concentration. The porous separator has a flow field plate that includes a first contact portion that is in contact with a gas diffusion layer or a membrane electrode assembly; a second contact portion that is in contact with a coolant channel; and a connection portion that is connected between the first contact portion and the second contact portion. Additionally, a passage aperture is formed in the connection portion, wherein a portion of an inside surface of the passage aperture protrudes toward a center of the passage aperture.