Leakage Studies With Seals for Solid-Oxide Fuel Cells

2007 ◽  
Author(s):  
Christopher K. Green ◽  
Jeffrey L. Streator ◽  
Comas Haynes ◽  
Edgar Lara-Curzio
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Steel Substrate ◽  
Vertical Direction ◽  
Solid Oxide ◽  
Physical Parameters ◽  
Oxide Fuel ◽  
Element Analysis ◽  
Gas Leakage ◽  
Interfacial Gap

This research seeks to characterize the gas leakage of a mica-based compressive seal assembly in planar solid-oxide fuel cells through modeling and experiment. In particular, it is of interest to assess how certain physical parameters (i.e., seal material composition, compressive applied stress, and surface finish) affect leakage rates. Finite element analysis is used to determine the macroscopic stresses and deformations in the sealing interface, while a microscale contact mechanics analysis is employed to model the role of surface roughness on the mean interfacial gap at the interface. An averaged Reynolds equation from mixed lubrication theory is applied to model the leakage flow across the sealed interface, which is of nanometer to micrometer dimensions in the vertical direction. In conjunction with the mathematical modeling, leakage results are reported. For these tests, an annular Inconel tube was pressed against a stainless steel substrate, creating an annular sealing zone. The inside of the tube is pressurized with a test gas, the mass of which is monitored during the leakage experiment. Test results are compared to model predictions.

Modeling Leakage With Mica-Based Compressive Seals for Solid Oxide Fuel Cells

Tribology ◽  
2006 ◽  
Author(s):  
Christopher K. Green ◽  
Jeffrey L. Streator ◽  
Comas Haynes
Keyword(s):  
Finite Element ◽  
Fuel Cells ◽  
Finite Element Model ◽  
Solid Oxide Fuel Cells ◽  
Element Model ◽  
High Energy ◽  
Solid Oxide ◽  
Physical Parameters ◽  
Oxide Fuel ◽  
Predictive Tool

Fuel cells represent a promising energy alternative to the traditional combustion of fossil fuels. In particular, solid oxide fuel cells (SOFCs) have been of interest due to their high energy densities and potential for stationary power applications. One of the key obstacles precluding the maturation and commercialization of planar SOFCs has been the lack of a robust sealant. This paper presents a computational model of leakage with the utilization of mica-based compressive seals. A finite element model is developed to ascertain the macroscopic stresses and deformations in the interface. In conjunction with the finite element model is a microscale contact mechanics model that accounts for the role of surface roughness in determining the mean interfacial gap at the interface. An averaged Reynolds equation derived from mixed lubrication theory is applied to model the leakage flow across the rough, annular interface. The composite model is applied as a predictive tool for assessing how certain physical parameters (i.e., seal material composition, compressive applied stress, surface finish, and interfacial conformity) affect seal leakage rates.

scholarly journals Finite element analysis and modelling of thermal stress in solid oxide fuel cells

2017 ◽  
Vol 231 (7) ◽  
pp. 654-665 ◽  
Author(s):  
Harald Schlegl ◽  
Richard Dawson
Keyword(s):  
Fuel Cells ◽  
Tensile Stress ◽  
Solid Oxide Fuel Cells ◽  
Large Scale ◽  
Thermal Stresses ◽  
Modelling And Simulation ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Element Analysis ◽  
Stress Relieving

Durability and reliability of anode supported solid oxide fuel cell stacks have proven unsatisfactory in large-scale trials, showing rapid failure, thermal cycling intolerance and step change in electrochemical performance most likely related to mechanical issues. Monitoring and understanding the mechanical conditions in the stack especially during temperature changes can lead to improvements of the design and of the operating regime targeting maximum durability. Within this project modelling and simulation of thermal stresses within the different parts of the cells and the stack and the validation of these models play a key role and were performed in this work. The modelling and simulation of stress and strain have been carried out using the FEA software ABAQUS™. Model variations documented the importance of exact knowledge of material properties like Young’s modulus, Poisson’s ratio, thermal expansion coefficient, thermal conductivity and creep viscosity. The benefit of literature data for these properties is limited by the fact that all these properties are highly dependent on the composition of materials but also on details of the fabrication process like mixing, fabrication technique and sintering temperature and duration. The work presented here is an investigation into the modelling techniques, which can be most efficiently applied to represent anode supported solid oxide fuel cells and demonstrates the temperature gradient and constraint on the stresses experienced in a typical design. Comparing different meshing elements representing the cell parts thin shell elements (S4R) provided the most efficiently derived solution. Tensile stress is most significant in the cathode layers reaching 155 MPa at working conditions. The stress relieving effect of creep led to a reduction of stress by up to 20% after 1000 h at 750 ℃, reducing the tensile stress in the cathode area to maximal 121 MPa. Constraint between bipolar plates increases the tensile stress, especially in the cathode layers leading to a peak value of 161 MPa.

Effect of Gas Leakage on the Performance of Planar Solid Oxide Fuel Cells

2020 ◽  
Vol MA2020-02 (40) ◽  
pp. 2621-2621
Author(s):  
Samuel Koomson ◽  
Arthur Ebenezer ◽  
ChoongGon Lee
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Gas Leakage

Influence of Processing Parameters on the Manufacturing of Anode-Supported Solid Oxide Fuel Cells by Different Wet Chemical Routes

2010 ◽  
Vol 638-642 ◽  
pp. 1098-1105 ◽  
Author(s):  
Norbert H. Menzler ◽  
Wolfgang Schafbauer ◽  
Hans Peter Buchkremer
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Process Parameters ◽  
Tape Casting ◽  
Solid Oxide ◽  
Physical Parameters ◽  
Substrate Thickness ◽  
Oxide Fuel ◽  
Wet Chemical ◽  
Substrate Types

Anode-supported solid oxide fuel cells (SOFC) are manufactured at Forschungszentrum Jülich by different wet chemical powder processes and subsequent sintering at high temperatures. Recently, the warm pressing of Coat-Mix powders has been replaced by tape casting as the shaping technology for the NiO/8YSZ-containing substrate in order to decrease the demand for raw materials due to lower substrate thickness and in order to increase reproducibility and fabrication capacities (scalable process). Different processing routes for the substrates require the adjustment of process parameters for further coating with functional layers. Therefore, mainly thermal treatment steps have to be adapted to the properties of the new substrate types in order to obtain high-performance cells with minimum curvature (for stack assembly). In this presentation, the influence of selected process parameters during cell manufacturing will be characterized with respect to the resulting physical parameters such as slurry viscosity, green tape thickness, relative density, substrate strength, electrical conductivity, and shrinkage of the different newly developed substrate types. The influencing factors during manufacturing and the resulting characteristics will be presented and possible applications for the various substrates identified.

Effect of an Anode Functional Layer on Cell Performance of Anode-Supported Solid Oxide Fuel Cells by a Decalcomania Method

2013 ◽  
Vol 51 (2) ◽  
pp. 125-130 ◽  
Author(s):  
Sun-Min Park ◽  
Hae-Ran Cho ◽  
Byung-Hyun Choi ◽  
Yong-Tae An ◽  
Ja-Bin Koo ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Solid Oxide ◽  
Cell Performance ◽  
Oxide Fuel ◽  
Functional Layer
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