Testing of solid oxide cells at high current densities
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André Weber
André Weber is working as senior scientist (Akademischer Oberrat) at the Institute for Applied Materials – Electrochemical Technologies (IAM-ET) at Karlsruhe Institute of Technology (KIT), Germany. Actually he is heading two groups related to fuel cells and & electrolyzer and battery research. His research is related to the electrical testing and modeling of fuel cells, electrolyzers and batteries, with a special emphasis on the detailed electrochemical characterization by means of impedance spectroscopy. The experimental and theoretical work of his research groups ranges from fundamental studies on model systems to the analysis of commercial products, aiming at a model based understanding of the complex coupling of electrochemical reactions and transport mechanisms within electrochemical devices. He has co-authored several book chapters, and more than 100 peer-reviewed journal papers on scientific topics related to fuel cells and batteries (
https://scholar.google.de/citations?hl=de&user=IGECnVQAAAAJ ).
Abstract
Solid Oxide Cells (SOCs) have gained an increasing interest as electrochemical energy converters due to their high efficiency, fuel flexibility and ability of reversible fuel cell/electrolysis operation. During the development process as well as in quality assurance tests, the performance of single cells and cell stacks is commonly evaluated by means of current/voltage- (CV-) characteristics. Despite of the fact that the measurement of a CV-characteristic seems to be simple compared to more complex, dynamic methods as electrochemical impedance spectroscopy or current interrupt techniques, the resulting performance strongly depends on the test setup and the chosen operating conditions.
In this paper, the impact of different single cell testing environments and operating conditions on the CV-characteristic of high performance cells is discussed. The influence of cell size, contacting and current collection, contact pressure, fuel flow rate and composition on the achievable cell performance is presented and limitations arising from the test bed and testing conditions will be pointed out. As today’s high performance cells are capable of delivering current densities of several ampere per cm2 a special emphasis will be laid on single cell testing in this current range.
Zusammenfassung
Festoxidzellen (Solid Oxide Cells, SOCs) haben aufgrund ihres hohen Wirkungsgrads, ihrer Brennstoffflexibilität und ihrer Fähigkeit zum reversiblen Brennstoffzellen/Elektrolyse-Betrieb als elektrochemische Energiewandler zunehmend an Interesse gewonnen. In der Entwicklung wie auch zur Qualitätssicherung wird die Leistung von Einzelzellen und Zellstacks in der Regel anhand von Strom/Spannungs-Kennlinien bewertet. Obwohl die Messung einer Strom/Spannungs-Kennlinie im Vergleich zu komplexeren, dynamischen Methoden wie der elektrochemischen Impedanzspektroskopie oder Current-Interrupt Techniken einfach zu sein scheint, hängt die resultierende Leistung stark vom Testaufbau und den gewählten Betriebsbedingungen ab.
In diesem Beitrag werden die Auswirkungen verschiedener Testumgebungen und Betriebsbedingungen auf die Kennlinie leistungsfähiger Festoxidzellen diskutiert. Der Einfluss von Zellgröße, Kontaktierung und Stromableitung, des Kontaktdrucks, der Brenngasausnutzung und der Brenngaszusammensetzung auf die erreichbare Zellleistung wird dargestellt. Einschränkungen durch den Prüfstand und die Prüfbedingungen werden diskutiert. Da die heutigen Hochleistungszellen in der Lage sind, Stromdichten von mehreren Ampere pro cm2 zu liefern, wird ein besonderer Schwerpunkt auf die Einzelzellenprüfung in diesem Strombereich gelegt.
About the author
André Weber is working as senior scientist (Akademischer Oberrat) at the Institute for Applied Materials – Electrochemical Technologies (IAM-ET) at Karlsruhe Institute of Technology (KIT), Germany. Actually he is heading two groups related to fuel cells and & electrolyzer and battery research. His research is related to the electrical testing and modeling of fuel cells, electrolyzers and batteries, with a special emphasis on the detailed electrochemical characterization by means of impedance spectroscopy. The experimental and theoretical work of his research groups ranges from fundamental studies on model systems to the analysis of commercial products, aiming at a model based understanding of the complex coupling of electrochemical reactions and transport mechanisms within electrochemical devices. He has co-authored several book chapters, and more than 100 peer-reviewed journal papers on scientific topics related to fuel cells and batteries (https://scholar.google.de/citations?hl=de&user=IGECnVQAAAAJ).
in-plane current:
b: width of the cell
local cell voltage:
cell voltage at x = L:
in-plane resistance:
local current density:
combining (A1) and (A6):
solution:
local current density:
local cell voltage:
References
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Articles in the same Issue
- Frontmatter
- Editorial
- In memoriam Fernando Puente León
- Beiträge
- Frequency and mode measurement techniques for megawatt-class gyrotrons
- Testing of solid oxide cells at high current densities
- Applications of radar measurement technology using 24 GHz, 61 GHz, 80 GHz and 122 GHz FMCW radar sensors
- Online harmonic error compensation of Atan2 function for a low-cost automotive sensor application
- Decision making at unsignalized inner city intersections using discrete events systems
Articles in the same Issue
- Frontmatter
- Editorial
- In memoriam Fernando Puente León
- Beiträge
- Frequency and mode measurement techniques for megawatt-class gyrotrons
- Testing of solid oxide cells at high current densities
- Applications of radar measurement technology using 24 GHz, 61 GHz, 80 GHz and 122 GHz FMCW radar sensors
- Online harmonic error compensation of Atan2 function for a low-cost automotive sensor application
- Decision making at unsignalized inner city intersections using discrete events systems
