Fuel Cell Separator Hole-Cap Structure for Sealable Flow Paths
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Solution Overview
Problem
Existing fuel cell separators face issues with gaskets being excessively compressed, leading to reduced flow path cross-sectional areas for reactant gases and coolant, deteriorated fluidity, and increased differential pressure due to the gas diffusion layer blocking through-holes, which complicates smooth fluid flow and sealability.
Innovation Solution
Incorporation of hole caps on the separator that define movement paths for fluids, preventing blockage by the gas diffusion layer and supporting the sealing member to maintain sufficient flow paths, along with reinforcing parts to stabilize the structure and ensure smooth fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fastening pressure is applied to ensure sealability between fuel cells, then sealability is improved, but the gasket is excessively compressed causing reduced flow path cross-sectional area
Solution Approach 1:
The gasket is divided into a first gasket portion and a second gasket portion with different thicknesses. The first gasket portion (at the through-hole) has greater thickness to resist compression and maintain flow path area, while the second gasket portion (at the sealing surface) has smaller thickness to provide adequate sealing under compression. This segmentation allows different regions of the gasket to fulfill different functional requirements simultaneously.
2Ease of operation
If the gas diffusion layer covers the through-hole to guide reactant gas, then fluid distribution is improved, but fluidity and flow efficiency deteriorate due to compression
Solution Approach 1:
The gasket is designed with non-uniform thickness distribution: the first gasket portion at the through-hole region has greater thickness to maintain open flow paths and minimize compression, while the second gasket portion at the sealing surface region has smaller thickness for effective sealing. This local quality variation optimizes both fluid distribution and flow efficiency in their respective regions.
3Area of stationary object
If the gasket thickness is increased to maintain flow path area, then flow efficiency is improved, but sealability deteriorates due to insufficient compression
Solution Approach 1:
The gasket is segmented into two distinct portions with different thicknesses optimized for different functions. The first portion maintains sufficient thickness to preserve flow path area and prevent excessive compression at the through-hole, while the second portion provides adequate thickness for effective sealing at the sealing surface when compressed by fastening pressure.
4Reliability
If the gasket is compressed to ensure sealing, then sealability is improved, but the flow path cross-sectional area is reduced
Solution Approach 1:
The gasket exhibits local quality variation with different thicknesses in different regions. The first gasket portion at the through-hole maintains greater thickness to resist compression and preserve flow path area, while the second gasket portion at the sealing surface has smaller thickness that allows adequate compression for sealing. This resolves the contradiction between sealability and flow efficiency.
Data Source
AI summary
A separator for a fuel cell, which is stacked on a gas diffusion layer provided on a membrane electrode assembly (MEA), includes a plate body stacked on the gas diffusion layer and including a flow path part to define a reaction region to react with the membrane electrode assembly and manifold parts spaced apart from the flow path part; through-holes disposed in the plate body to guide target fluids that have passed through the manifold parts to the flow path part; and hole caps disposed on one surface of the plate body that faces the gas diffusion layer to at least partially cover the through-holes, the hole caps defining movement paths through which the target fluids move.