Solid Oxide Fuel Cell Connection Layer Design
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Solution Overview
Problem
Solid oxide fuel cells face issues with gas leakage, electrode reaction, and stripping of connection layers during operation, particularly due to the use of ceramic connectors which are not dense and can react with electrodes.
Innovation Solution
A connection layer composed of a two-layer structure, where the first layer contains La-ferrite with Sr, Ca, or Ba, and the second layer includes doped ceria, applied densely on porous electrodes to prevent gas leakage and electrode reaction, ensuring electrical connectivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a ceramic connector is used, then mechanical properties at high temperature are improved, but gas leakage and electrode reaction occur due to insufficient density
Solution Approach 1:
The patent uses a composite connection layer consisting of a first layer (La-ferrite with Sr, Ca, or Ba) and a second layer (La-ferrite with ceria dopants), creating a dense composite structure that prevents gas leakage while maintaining high temperature mechanical properties. This composite approach resolves the contradiction by combining materials that provide both structural integrity and gas tightness.
Solution Approach 2:
The patent changes the compositional parameters of the connection layer by incorporating specific dopants (Sr, Ca, Ba, and ceria) into the La-ferrite structure. This parameter modification increases the density of the connection layer from the typical ceramic level to a dense film level, preventing gas leakage while maintaining thermal stability.
2Reliability
If a dense connection layer is applied, then gas leakage is prevented, but manufacturing complexity increases
Solution Approach 1:
The connection layer is segmented into two distinct functional layers: a first layer providing structural support and a second layer enhancing density and gas tightness. This segmentation allows each layer to be optimized for its specific function while maintaining overall manufacturability through a systematic structure.
Solution Approach 2:
Different regions of the connection layer are assigned different compositions and properties: the first layer contains La-ferrite with Sr, Ca, or Ba for structural stability, while the second layer contains La-ferrite with ceria dopants for enhanced density. This local quality differentiation achieves gas tightness without uniformly increasing complexity throughout the entire structure.
3Reliability
If a connection layer is applied to prevent gas leakage, then electrical conductivity may be reduced
Solution Approach 1:
The composite connection layer combines La-ferrite-based materials with different functional properties: the first layer provides structural stability and the second layer with ceria dopants enhances both density and electrical conductivity. This composite approach ensures that gas tightness is achieved without sacrificing electrical conductivity, as the conductive ceria-containing layer compensates for the insulating nature of dense ceramic structures.
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 dense connection layer effectively prevents gas leakage, maintains electrical conductivity, and avoids electrode reactions, enhancing the long-term performance and stability of solid oxide fuel cells by reducing area specific resistance and preventing stripping.
Implementation Method 1
a first layer containing La-ferrite including one or more selected from the group consisting of Sr, Ca and Ba
Implementation Method 2
a second layer containing La-ferrite including one or more selected from the group consisting of Sr, Ca and Ba, and one or more cerias selected from the group consisting of GDC (Gd doped ceria), LDC (La-doped ceria) and SDC (Sm-doped ceria)
Implementation Method 3
The connection layer of the solid oxide fuel cell according to the present invention has sufficient conductivity, so that the unit cells are electrically connected to each other
Implementation Method 4
The connection layer of the solid oxide fuel cell according to the present invention does not react with an electrode
Implementation Method 5
The connection layer of the solid oxide fuel cell according to the present invention is not stripped from an electrode during the operation of the fuel cell
Data Source
AI summary
The present invention relates to a solid oxide fuel cell, which includes a plurality of unit cells and a connection layer between the plurality of unit cells, wherein each of the unit cells includes an anode, a cathode and a solid electrolyte between the anode and the cathode, and the connection layer includes i) a first layer containing La-ferrite including one or more selected from the group consisting of Sr, Ca and Ba; and ii) a second layer containing La-ferrite including one or more selected from the group consisting of Sr, Ca and Ba, and one or more cerias selected from the group consisting of GDC (Gd doped ceria), LDC (La-doped ceria) and SDC (Sm-doped ceria), wherein the first layer is in contact with the cathode of each of the unit cells and the second layer is in contact with the anode of each of the unit cells.