Fuel Cell Separator Lands and Stepped Channels for GDL Protection
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Solution Overview
Problem
Fuel cell stacks face challenges in maximizing reactant gas reaction areas and delivery efficiency due to the complexity and cost of manufacturing separators with porous members, which also lead to increased electrical resistance and potential deformation of gas diffusion layers.
Innovation Solution
A separator design with stepped portions and lands on a plate body, allowing reactant gas flow in intersecting directions without a porous member, reducing contact resistance and stress concentration, and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a porous member (metal foam or wire mesh) is provided on the separator to improve reactant gas diffusion and water discharge, then gas diffusion performance is improved, but the structure and manufacturing process become complicated and manufacturing costs increase
Solution Approach 1:
The invention extracts and removes the separate porous member from the separator structure, integrating its functions directly into the separator plate through stepped portions and lands. This eliminates the need for additional porous materials while maintaining gas diffusion efficiency and simplifying the overall structure.
Solution Approach 2:
The invention merges the functions of the porous member (gas diffusion, water discharge, electrical conduction) directly into the separator plate by forming stepped portions and lands as integral parts of the separator. This combines multiple components into one, reducing structural complexity and manufacturing steps.
2Productivity
If a porous member is disposed between the gas diffusion layer and the separator, then gas diffusion is improved, but contact area between gas diffusion layer and separator decreases causing increased electrical resistance
Solution Approach 1:
The invention removes the porous member that was causing contact area reduction, and instead creates direct contact between the gas diffusion layer and separator through lands. This eliminates the electrical resistance issue while maintaining gas diffusion performance.
Solution Approach 2:
The stepped portions act as intermediaries that facilitate both gas diffusion and maintain electrical contact. The lands provide a direct conductive path between the gas diffusion layer and separator, serving as an effective intermediary that solves both gas diffusion and electrical resistance issues simultaneously.
3Productivity
If a porous member with irregular cross-sectional shape is used, then gas diffusion is improved, but stress concentration occurs causing deformation and damage to the gas diffusion layer during fastening
Solution Approach 1:
The invention applies local quality by creating stepped portions with specific geometric features on the separator plate. These stepped portions provide localized gas diffusion enhancement without the irregular shapes of porous members, thereby avoiding stress concentration while maintaining diffusion efficiency.
Solution Approach 2:
The invention converts the potential harm of irregular porous member shapes (stress concentration) into a benefit by using regular stepped portions. The well-defined geometry of stepped portions provides stress distribution during fastening while still achieving enhanced gas diffusion through the stepped structure.
4Productivity
If a separate porous member is added to the separator, then reactant gas delivery efficiency is improved, but manufacturing costs and manufacturing process complexity increase
Solution Approach 1:
The invention merges the porous member's gas delivery functions directly into the separator plate through stepped portions and lands. This integration eliminates the need for separate porous components and their associated manufacturing steps, reducing manufacturing complexity and costs while maintaining delivery efficiency.
Solution Approach 2:
The separator plate with stepped portions performs multiple functions: it provides gas distribution channels, creates gas diffusion areas through stepped portions, enables water discharge, maintains electrical contact through lands, and simplifies manufacturing. This multi-functional design eliminates the need for separate porous members.
Data Source
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AI summary
A separator for a fuel cell, which is stacked on a reaction layer including a membrane electrode assembly (MEA) and a gas diffusion layer (GDL) stacked on the MEA includes: a plate body stacked on the GDL; stepped portions, on which a reactant gas flows in a first direction, disposed on a first surface of the plate body, the first surface facing the GDL, the stepped portions disposed in a second direction that intersects the first direction in which the reactant gas flows; lands disposed on the stepped portions so as to be spaced apart from one another in the second direction, the lands being in contact with the GDL; first channels defined between the GDL and the stepped portions so as to be disposed between adjacent lands, the first channels configured such that the reactant gas flows along the first channels; and second channels defined between the plate body and the GDL so as to communicate with the first channels, the second channels configured such that the reactant gas flows along the second channels.