Fuel Cell Interconnects with Dielectric Layers
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Solution Overview
Problem
Conventional fuel cell interconnect designs face challenges with non-uniform fuel distribution, density variations, and potential for cracks in ceramic electrolytes due to through holes, leading to reduced stack yield and performance, along with complications in manufacturing and operational efficiency.
Innovation Solution
The introduction of cross-flow interconnects without through holes, using chromium-alloy interconnects with dielectric layers comprising a glass-containing component and corrosion barrier materials, and electrolyte reinforcement layers to enhance uniform fuel distribution and prevent electrical shorting and seal degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If through holes are used in interconnects for fuel distribution, then fuel can be supplied to cells, but density variations and cracks occur in ceramic electrolytes
Solution Approach 1:
The invention removes the through holes from the interconnect design, extracting the problematic element that caused density variations and cracks in the ceramic electrolyte. Fuel distribution is achieved through alternative means without penetrating the interconnect structure, thereby preserving electrolyte integrity while maintaining fuel supply capability.
Solution Approach 2:
The invention introduces a dielectric layer as an intermediary component between the interconnect and the electrolyte. This dielectric layer serves as a mediator that enables fuel distribution while protecting the electrolyte from the harmful effects of direct through-hole contact, thus resolving the contradiction between fuel supply and electrolyte integrity.
2Reliability
If conventional dielectric layers are used on interconnects, then electrical insulation is provided, but seal degradation occurs
Solution Approach 1:
The invention employs a composite dielectric layer composition that combines multiple materials with complementary properties. This composite structure provides both the necessary electrical insulation and enhanced chemical stability to prevent seal degradation, thereby extending seal life while maintaining electrical insulation functionality.
Solution Approach 2:
The invention modifies the chemical and physical parameters of the dielectric layer, such as composition, thickness, and microstructure, to optimize both electrical insulation performance and chemical compatibility with seals. By adjusting these parameters, the dielectric layer becomes more resistant to causing seal degradation over time.
3Reliability
If chromium-alloy interconnects are used, then electrical conductivity is improved, but corrosion resistance may be compromised
Solution Approach 1:
The invention uses chromium-alloy interconnects with specific compositional ratios and introduces protective coatings or surface treatments that form composite structures. The chromium alloy provides the necessary electrical conductivity, while the additional protective layers or modified surface composition enhances corrosion resistance, allowing both requirements to be satisfied simultaneously.
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
This design improves fuel cell stack performance by ensuring uniform contact and fuel distribution, reducing density variations, and preventing electrical shorting and seal degradation, thereby enhancing operational efficiency and extending the life of the fuel cell.
Implementation Method 1
dielectric layers disposed on the interconnects, the dielectric layers comprising a first glass-containing component and a corrosion barrier material
Implementation Method 2
after sintering at a temperature ranging from about 950° C. to about 1050° C., for a time period of at least 15 minutes
Implementation Method 3
the first glass-containing component is at least 50% (e.g., by volume) amorphous
Implementation Method 4
the corrosion barrier material comprises zirconium silicate (ZrSiO4)), potash feldspar (KAlSi3O8), alumina (Al2O3), lanthanum trisilicate (La2Si3O9), silicon carbide, or any combination thereof
Data Source
AI summary
A fuel cell stack includes stacked solid oxide fuel cells, interconnects disposed between the fuel cells, and dielectric layers disposed on the interconnects and including a first glass-containing component and a corrosion barrier material. Optionally, the dielectric layers may cover only a portion of the interconnect riser seal surfaces which are covered by riser seals. Additionally or alternatively, the fuel cell stack may include an electrolyte reinforcement layer on the electrolyte of the solid oxide fuel cells.