Modeling and Simulation of the Dynamic Behavior of Portable Proton Exchange Membrane Fuel Cells

Lade...
Vorschaubild
Dateien
ZieglerC.pdf
ZieglerC.pdfGröße: 6.24 MBDownloads: 930
Datum
2005
Autor:innen
Ziegler, Christoph
Herausgeber:innen
Kontakt
ISSN der Zeitschrift
Electronic ISSN
ISBN
Bibliografische Daten
Verlag
Schriftenreihe
Auflagebezeichnung
DOI (zitierfähiger Link)
ArXiv-ID
Internationale Patentnummer
Angaben zur Forschungsförderung
Projekt
Open Access-Veröffentlichung
Open Access Green
Sammlungen
Core Facility der Universität Konstanz
Gesperrt bis
Titel in einer weiteren Sprache
Modellierung und Simulation der Dynamik von portablen Polymer-Elektrolyt-Membran-Brennstoffzellen
Forschungsvorhaben
Organisationseinheiten
Zeitschriftenheft
Publikationstyp
Dissertation
Publikationsstatus
Published
Erschienen in
Zusammenfassung

This thesis focuses on the modeling and simulation of the PEMFC.
The physical and electrochemical fundamentals necessary for fuel cell modeling are introduced in Chapter 2.

Planar self-breathing fuel cells in printed circuit board (PCB) technology are currently being developed at the Fraunhofer Institute for Solar Energy Systems.


In order to analyze the operational behavior, a mathematical model of planar self-breathing fuel cells is developed and validated in Chapter 3.
The multicomponent transport of the species is considered as well as the couplings between the transport processes of heat, charge, and
mass and the electrochemical reactions. Furthermore, to explain the oxygen mass transport limitation in the porous electrode of the cathode side an agglomerate model for the oxygen reduction reaction is developed.
The system of coupled partial differential equations (PDEs) is implemented in FEMLAB^TM. For the discretization of the PDEs the Galerkin finite
element method is used. The resulting system of nonlinear equations is solved with the Newton method.
The cell model is validated by comparison of the measured overall performance of a planar self-breathing fuel cell
with the predictions of the model.
Based on the modeling results, a theoretical study of planar and self-breathing fuel cells is presented.
The investigation of the operating behavior reveals the most important properties.

In Chapter 4 the important issue of liquid water generation and transport in PEMFCs is addressed.
One of the major tasks when operating this type of fuel cell is avoiding the complete flooding of the PEMFC during operation.
A one-dimensional and isothermal model is developed that is based on a coupled system of partial differential equations.
The model contains a dynamic and two-phase description of the proton exchange membrane fuel cell. The mass transport in the gas phase and in the liquid phase is considered as well as the phase transition between liquid water and water vapor. The transport of charges and the electrochemical reactions are part of the model. Flooding effects that are caused by liquid water accumulation are described by this model.
Moreover, the model contains a time-dependent description of the membrane that accounts for Schroeder's paradox. The membrane model is coupled with the two-phase flow equations in the electrodes.
The model is implemented in the software FEMLAB^TM.
The time-dependent PDEs are discretized in space by using the Galerkin method with time-dependent nodal parameters.
The resulting system of ordinary differential equations is solved using the implicit multistep solver ode15s of MATLAB^TM.
The validity of the novel model approach for the membrane is shown by the comparison of the measured and the simulated cell resistance.
The model is applied to simulate cyclic voltammograms.
A hysteresis effect of the current-voltage relation and a time-dependent current density in the two-phase regime is found in both the simulation and the experiment.


Chapter 5 is focused on the dynamic investigation of PEMFC stacks.
Understanding the dynamic behavior of fuel cell stacks is important for the operation and control of fuel cell stacks.
Using the single cell model of Chapter 3 and the dynamic model of Chapter 4 as basis, a mathematical model
of a PEMFC stack is developed. However, due to the complexity of a fuel cell stack, the spatial resolution and dynamic description of the liquid water transport
are not accounted for. These restrictions allow for direct comparison between the solution variables of the model and measurement data and for the simulation of
hours of stack operation, which could otherwise not be achieved.
The model is time-dependent and non-isothermal. It is based on energy and mass balance equations. Heat and mass transfer by convection and conduction within the stack, as well as changes due to the electrochemical reactions and the phase transition of water, are taken into account. The mass and heat transport equations are coupled with an electrical model that is based on the Tafel equation and a membrane model that accounts for the net-transfer of water through the membrane. The mathematical formulation of the model is a coupled differential algebraic equation system that contains ordinary differential equations in time describing the heat and mass transfer. An algebraic equation is used to describe the electrochemical reaction at the cathode.
The model is implemented in MATLAB^TM. The system of equations is solved by using the implicit multistep solver ode15s.
The mathematical stack model is capable of simulating arbitrary load profiles.
These properties facilitate the application of the dynamic PEMFC stack model in system simulation and model-based control.
The validity of the model approach is proven by comparing simulated and measured load profiles and stack temperatures.

Zusammenfassung in einer weiteren Sprache

Der Schwerpunkt dieser Arbeit liegt im Bereich der Modellierung und Simulation von Polymer-Elektrolyt-Membran-Brennstoffzellen.

In Kapitel 2 werden die physikalischen und elektrochemischen Grundlagen hergeleitet, die für die mathematische Beschreibung einer Polymer-Elektrolyt-Membran-Brennstoffzelle notwendig sind.
Am Fraunhofer Institut für Solare Energiesysteme werden flache selbstatmende Brennstoffzellen in Leiterplattenbauweise entwickelt.
Um das Betriebsverhalten dieses Zelltyps zu untersuchen wird ein mathematisches Modell einer flachen selbstatmenden Zelle entwickelt und durch den Vergleich mit Messungen validiert. Das Modell ist zweidimensional und beschreibt ein Symmetrieelement einer flachen Zelle, deren Kathode zu 80% offen ist. Die Mehrkomponentendiffusion der Gase wird berücksichtigt ebenso wie die Kopplungen zwischen Energie- und Massentransport sowie den elektrochemischen Reaktionen. Ein Agglomeratmodell wird entwickelt, das die Sauerstoffreduktion in Verbindung mit dem Massentransportwiderstand der porösen Elektrode beschreibt.
Das System gekoppelter partieller Differenzialgleichungen (PDGen) ist in FEMLAB^TM implementiert. Für die Diskretisierung der PDGen wird die Galerkin-Finite-Element-Methode verwendet. Das resultierende System nichtlinearer Gleichungen wird mit dem gedämpften Newtonverfahren gelöst.
Zur Validierung des Modells werden die simulierte und die gemessene Strom-Spannungskennlinie miteinander verglichen.
Ein gutes Verständnis der Wasserentstehung und des Wassertransportes in Polymer-Elektrolyt-Membran-Brennstoffzellen ist wichtig, um im Betrieb zuverlässig die Flutung oder Austrocknung der Brennstoffzelle vermeiden zu können. In Kapitel 4 dieser Arbeit wird daher ein eindimensionales isothermes Modell entwickelt, das den zeitabhängigen Zweiphasentransport in der Brennstoffzelle beschreibt. Neben der Beschreibung der Transportmechanismen im gasförmigen und im flüssigen Zustand werden die elektrochemischen Reaktionen und der Ladungstransport in diesem Modell behandelt.
Durch die Kopplung der Zweiphasentransportgleichungen an die Beschreibung der Gasdiffusion und die elektrochemischen Reaktionen wird das Flutungsverhalten der Zelle dynamisch beschrieben. Zusätzlich wird ein Membranmodell entwickelt, das das Schrödersche Paradoxon beschreibt und mit den Zweiphasentransportgleichungen gekoppelt ist.
Das Modell ist in FEMLAB^TM implementiert. Die zeitabhängigen PDGen werden hinsichtlich des Ortes mit der Galerkin-Finite-Element-Methode diskretisiert. Durch die Verwendung zeitabhängiger Knotenvariablen erhält man ein System von gewöhnlichen Differenzialgleichungen in der Zeit, das mit dem impliziten Löser ode15s von MATLAB^TM gelöst wird.
Das Modell wird durch den Vergleich zwischen Simulationsergebnissen und zeitabhängigen Messergebnissen validiert. Das Anlegen einer periodischen Zellspannung mit einer Periodendauer im Bereich von Minuten führt zu einer Strom-Spannungskurve, die charakteristisch für den Transport flüssigen Wassers in der Zelle ist.

In Kapitel 5 wird ein dynamisches Modell eines Brennstoffzellenstacks entwickelt. Mit diesem Modell lässt sich das dynamische Verhalten eines Brennstoffzellenstacks beschreiben. Das Modell ist für die Optimierung das Betriebsverhaltens und für den Regelungsentwurf geeignet.
Das Stackmodell berücksichtigt keine ortsaufgelösten Effekte, und auch die explizite Behandlung des Zweiphasentransportes ist nicht Teil des Modells. Diese Einschränkungen ermöglichen den direkten Vergleich der Lösungsvariablen des Modells mit Messwerten und die Simulation des Stackbetriebs über mehrere Stunden. Das dynamische Modell basiert auf Energie- und Massenbilanzgleichungen.
Die elektrochemischen Reaktionen und der Phasenübergang von Wasser sind Teil des Modells. Die Energie- und Massenbilanzgleichungen sind mit der Tafelgleichung und einem Membranmodell gekoppelt, das den effektiven Wassertransport durch die Membran beschreibt.
Das System gewöhnlicher Differenzialgleichungen ist in MATLAB^TM implementiert und wird mit dem impliziten Löser ode15s gelöst. Das Modell ist numerisch effizient, so dass eine Betriebszeit von über einer Stunde auf einem Rechner mit 1533 MHz-Prozessor in weniger als einer Sekunde simuliert werden kann.
Die Simulationsergebnisse geben das dynamische Verhalten eines Brennstoffzellenstacks wieder. Beliebige Lastprofile können simuliert werden, was die Anwendung des Modells in der Systemsimulation und der modellbasierten Regelung ermöglicht.
Zur Demonstration dieser Modelleigenschaften dient die Simulation eines stufenförmigen Stromdichteprofils.
Ein Stack mit einer Nennleistung von 30 W und einer Spitzenleistung von 70 W wird experimentell untersucht. Durch den Vergleich von simulierter und gemessener Stackspannung und Stacktemperatur wird das Modell validiert.

Fachgebiet (DDC)
530 Physik
Schlagwörter
modeling, fuel cell, two-phase, planar, stack
Konferenz
Rezension
undefined / . - undefined, undefined
Zitieren
ISO 690ZIEGLER, Christoph, 2005. Modeling and Simulation of the Dynamic Behavior of Portable Proton Exchange Membrane Fuel Cells [Dissertation]. Konstanz: University of Konstanz
BibTex
@phdthesis{Ziegler2005Model-9012,
  year={2005},
  title={Modeling and Simulation of the Dynamic Behavior of Portable Proton Exchange Membrane Fuel Cells},
  author={Ziegler, Christoph},
  address={Konstanz},
  school={Universität Konstanz}
}
RDF
<rdf:RDF
    xmlns:dcterms="http://purl.org/dc/terms/"
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:bibo="http://purl.org/ontology/bibo/"
    xmlns:dspace="http://digital-repositories.org/ontologies/dspace/0.1.0#"
    xmlns:foaf="http://xmlns.com/foaf/0.1/"
    xmlns:void="http://rdfs.org/ns/void#"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema#" > 
  <rdf:Description rdf:about="https://kops.uni-konstanz.de/server/rdf/resource/123456789/9012">
    <foaf:homepage rdf:resource="http://localhost:8080/"/>
    <dcterms:title>Modeling and Simulation of the Dynamic Behavior of Portable Proton Exchange Membrane Fuel Cells</dcterms:title>
    <void:sparqlEndpoint rdf:resource="http://localhost/fuseki/dspace/sparql"/>
    <dcterms:abstract xml:lang="eng">This thesis focuses on the modeling and simulation of the PEMFC.&lt;br /&gt;The physical and electrochemical fundamentals necessary for fuel cell modeling are introduced in Chapter 2.&lt;br /&gt;&lt;br /&gt;Planar self-breathing fuel cells in printed circuit board (PCB) technology are currently being developed at the Fraunhofer Institute for Solar Energy Systems.&lt;br /&gt;&lt;br /&gt;&lt;br /&gt;In order to analyze the operational behavior, a mathematical model of planar self-breathing fuel cells is developed and validated in Chapter 3.&lt;br /&gt;The multicomponent transport of the species is considered as well as the couplings between the transport processes of heat, charge, and&lt;br /&gt;mass and the electrochemical reactions. Furthermore, to explain the oxygen mass transport limitation in the porous electrode of the cathode side an agglomerate model for the oxygen reduction reaction is developed.&lt;br /&gt;The system of coupled partial differential equations (PDEs) is implemented in FEMLAB^TM. For the discretization of the PDEs the Galerkin finite&lt;br /&gt;element method is used. The resulting system of nonlinear equations is solved with the Newton method.&lt;br /&gt;The cell model is validated by comparison of the measured overall performance of a planar self-breathing fuel cell&lt;br /&gt;with the predictions of the model.&lt;br /&gt;Based on the modeling results, a theoretical study of planar and self-breathing fuel cells is presented.&lt;br /&gt;The investigation of the operating behavior reveals the most important properties.&lt;br /&gt;&lt;br /&gt;In Chapter 4 the important issue of liquid water generation and transport in PEMFCs is addressed.&lt;br /&gt;One of the major tasks when operating this type of fuel cell is avoiding the complete flooding of the PEMFC during operation.&lt;br /&gt;A one-dimensional and isothermal model is developed that is based on a coupled system of partial differential equations.&lt;br /&gt;The model contains a dynamic and two-phase description of the proton exchange membrane fuel cell. The mass transport in the gas phase and in the liquid phase is considered as well as the phase transition between liquid water and water vapor. The transport of charges and the electrochemical reactions are part of the model. Flooding effects that are caused by liquid water accumulation are described by this model.&lt;br /&gt;Moreover, the model contains a time-dependent description of the membrane that accounts for Schroeder's paradox. The membrane model is coupled with the two-phase flow equations in the electrodes.&lt;br /&gt;The model is implemented in the software FEMLAB^TM.&lt;br /&gt;The time-dependent PDEs are discretized in space by using the Galerkin method with time-dependent nodal parameters.&lt;br /&gt;The resulting system of ordinary differential equations is solved using the implicit multistep solver ode15s of MATLAB^TM.&lt;br /&gt;The validity of the novel model approach for the membrane is shown by the comparison of the measured and the simulated cell resistance.&lt;br /&gt;The model is applied to simulate cyclic voltammograms.&lt;br /&gt;A hysteresis effect of the current-voltage relation and a time-dependent current density in the two-phase regime is found in both the simulation and the experiment.&lt;br /&gt;&lt;br /&gt;&lt;br /&gt;Chapter 5 is focused on the dynamic investigation of PEMFC stacks.&lt;br /&gt;Understanding the dynamic behavior of fuel cell stacks is important for the operation and control of fuel cell stacks.&lt;br /&gt;Using the single cell model of Chapter 3 and the dynamic model of Chapter 4 as basis, a mathematical model&lt;br /&gt;of a PEMFC stack is developed. However, due to the complexity of a fuel cell stack, the spatial resolution and dynamic description of the liquid water transport&lt;br /&gt;are not accounted for. These restrictions allow for direct comparison between the solution variables of the model and measurement data and for the simulation of&lt;br /&gt;hours of stack operation, which could otherwise not be achieved.&lt;br /&gt;The model is time-dependent and non-isothermal. It is based on energy and mass balance equations. Heat and mass transfer by convection and conduction within the stack, as well as changes due to the electrochemical reactions and the phase transition of water, are taken into account. The mass and heat transport equations are coupled with an electrical model that is based on the Tafel equation and a membrane model that accounts for the net-transfer of water through the membrane. The mathematical formulation of the model is a coupled differential algebraic equation system that contains ordinary differential equations in time describing the heat and mass transfer. An algebraic equation is used to describe the electrochemical reaction at the cathode.&lt;br /&gt;The model is implemented in MATLAB^TM. The system of equations is solved by using the implicit multistep solver ode15s.&lt;br /&gt;The mathematical stack model is capable of simulating arbitrary load profiles.&lt;br /&gt;These properties facilitate the application of the dynamic PEMFC stack model in system simulation and model-based control.&lt;br /&gt;The validity of the model approach is proven by comparing simulated and measured load profiles and stack temperatures.</dcterms:abstract>
    <dc:creator>Ziegler, Christoph</dc:creator>
    <dspace:isPartOfCollection rdf:resource="https://kops.uni-konstanz.de/server/rdf/resource/123456789/41"/>
    <dc:date rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2011-03-24T17:52:49Z</dc:date>
    <dc:format>application/pdf</dc:format>
    <dc:contributor>Ziegler, Christoph</dc:contributor>
    <dcterms:hasPart rdf:resource="https://kops.uni-konstanz.de/bitstream/123456789/9012/1/ZieglerC.pdf"/>
    <dcterms:available rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2011-03-24T17:52:49Z</dcterms:available>
    <dspace:hasBitstream rdf:resource="https://kops.uni-konstanz.de/bitstream/123456789/9012/1/ZieglerC.pdf"/>
    <dcterms:alternative>Modellierung und Simulation der Dynamik von portablen Polymer-Elektrolyt-Membran-Brennstoffzellen</dcterms:alternative>
    <dcterms:rights rdf:resource="https://rightsstatements.org/page/InC/1.0/"/>
    <dc:language>eng</dc:language>
    <dc:rights>terms-of-use</dc:rights>
    <bibo:uri rdf:resource="http://kops.uni-konstanz.de/handle/123456789/9012"/>
    <dcterms:issued>2005</dcterms:issued>
    <dcterms:isPartOf rdf:resource="https://kops.uni-konstanz.de/server/rdf/resource/123456789/41"/>
  </rdf:Description>
</rdf:RDF>
Interner Vermerk
xmlui.Submission.submit.DescribeStep.inputForms.label.kops_note_fromSubmitter
Kontakt
URL der Originalveröffentl.
Prüfdatum der URL
Prüfungsdatum der Dissertation
November 21, 2005
Finanzierungsart
Kommentar zur Publikation
Allianzlizenz
Corresponding Authors der Uni Konstanz vorhanden
Internationale Co-Autor:innen
Universitätsbibliographie
Begutachtet
Diese Publikation teilen