Permeable Metal Substrate for Solid Oxide Fuel Cells
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Solution Overview
Problem
Conventional solid oxide fuel cells (SOFCs) with thick support elements face poor permeability issues, leading to difficulties in hydrogen entry and water vapor drainage, resulting in polarization losses and reduced cell output, while thinner support elements compromise mechanical strength and long-term stability.
Innovation Solution
A permeable metal substrate with a matching expansion coefficient to the electrolyte is designed, featuring straight gas channels and a porous anode layer, enhanced by laser drilling and high-temperature brazing, to improve hydrogen diffusion and water vapor drainage, and featuring a porous anode layer with micron and sub-micron structures for improved fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the support element is increased to provide good mechanical support, then the mechanical strength is improved, but the permeability deteriorates making it difficult for hydrogen to enter the anode layer and for water vapor to be drained out
Solution Approach 1:
The support element is segmented into multiple layers with different functions: a dense bottom layer for mechanical strength and a porous top layer for permeability. This segmentation allows each layer to optimize its specific function without compromising the other, resolving the contradiction between strength and permeability.
Solution Approach 2:
Different regions of the support element have different structural properties. The bottom layer has high density and low porosity for mechanical support, while the top layer has high porosity for gas permeability. This local quality variation allows the single component to satisfy conflicting requirements in different spatial zones.
2Reliability
If the thickness of the support element is reduced to improve permeability, then the permeability is improved, but the mechanical strength is weakened affecting long-term operation stability
Solution Approach 1:
The support element is divided into functional segments where the dense bottom layer provides mechanical strength and the porous top layer provides permeability. This allows the overall thickness to be reduced while maintaining both strength and permeability through optimized layering rather than uniform thickness.
Solution Approach 2:
The support element uses a composite structure combining dense metal material for strength and porous metal material for permeability. This composite approach allows the integration of materials with complementary properties to simultaneously achieve mechanical strength and gas permeability.
3Strength
If granular powders are stacked by powder metallurgy to form a permeable metal substrate, then the mechanical strength is achieved, but the gas channels become irregular and tortuous causing resistance to gas flows
Solution Approach 1:
Instead of forming pores by removing material or relying on random void spaces between particles, the invention inverts the approach by directly forming straight through-holes using laser drilling. This creates optimized gas channels with minimal tortuosity, dramatically improving gas flow efficiency while maintaining mechanical strength through the dense bottom layer.
4Strength
If the support element is made with a cement anode material, then the mechanical support is provided, but the permeability is poor resulting in polarization losses
Solution Approach 1:
The invention transitions from homogeneous cement anode material to a composite metal support structure with controlled porosity. The metal-based composite support element provides both the mechanical strength of traditional cement materials and the enhanced permeability needed to prevent polarization losses, resolving the contradiction between structural support and gas transport.
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
The solution enhances hydrogen flow into the anode and water vapor drainage, maintains mechanical strength, and minimizes deformation, resulting in improved fuel cell performance and stability under thermal cycling and rapid startup conditions.
Implementation Method 1
a plurality of straight gas channels are formed on the metallic interconnect by using a laser drilling process
Implementation Method 2
enhanced by laser drilling and high-temperature brazing
Implementation Method 3
improve hydrogen diffusion and water vapor drainage
Implementation Method 4
A permeable metal substrate with a matching expansion coefficient to the electrolyte is designed
Data Source
AI summary
The invention provides a permeable metal substrate and its manufacturing method. The permeable metal substrate includes a substrate body and a permeable powder layer. The permeable powder layer is located on the top of the substrate body. The substrate body can be a thick substrate or formed of a thick substrate and a thin substrate that are welded together. Both the thick and thin substrates have a plurality of permeable straight gas channels. In addition, a metal-supported solid oxide fuel cell and its manufacturing method are also provided.