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High Temperature Ceramic Fuel Cell Measurement and Diagnostics for Application to Solid Oxide Fuel Cell Systems PNNL-13716








High Temperature Ceramic
Fuel Cell Measurement and Diagnostics
for Application to Solid Oxide Fuel Cell
Systems



T. M. Koehler
D. B. Jarrell
L. J. Bond






October 2001











Prepared for the U.S. Department of Energy
under Contract DE-AC06-76RL01830


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High Temperature Ceramic Fuel Cell Measurement
and Diagnostics for Application to Solid Oxide Fuel
Cell Systems




T. M. Koehler
D. B. Jarrell
L. J. Bond




October 2001





Prepared for
the U.S. Department of Energy
under Contract DE-AC06-76RL01830






Pacific Northwest National Laboratory
Richland, Washington 99352



iii
Summary



There is a growing need for high efficiency, portable and distributed electric power generation. One
family of technologies to meet these needs consists of the various forms of fuel cells. This paper is
focused on the assessment of sensors and measurement technologies needed to give improved control,
diagnostics and data for prognostics for use with high temperature ceramic fuel cells, and for initial
demonstration of solid oxide fuel cells (SOFC). This paper also highlights the many challenges and
complexities involved with SOFC technology, such as the lack of continuity between research projects,
making it difficult to advance the technology in a cooperative manner. Research programs are noted;
particularly those that are starting to provide continuity across the wide variety of research projects
underway, such as the International Energy Agency.


This paper is the result of an extensive literature review and technology evaluation, performed to
determine the status of sensors and measurement technologies. It became apparent that many researchers
are trying to overcome the same fuel cell design challenges. All researchers have found it difficult to
obtain sound data from measurements inside inaccessible designs and heavily insulated enclosures
operating at high temperatures. Although some advancement has been made in materials, systems
modeling, and innovative manufacturing techniques, few answers have been found in the measurement
and diagnostics field.


Understandably, most approaches to measurements and diagnostics in fuel cells have been to extend
an existing practice to solid oxide fuel cells, such as adapting established aqueous electrochemistry
techniques (i.e., impedance spectroscopy). Although this technique has manifested some key characteris-
tics of the SOFC, and is arguably one of the most advanced techniques in this field, work is still needed to
resolve disagreements on the application and interpretation methods.


Realizing the many constraints involved in SOFC testing and resolved to the fact that simple
approaches may not be the complete answer, several innovative techniques and geometries have been
tried and included in this report. Many researchers are using a combination of in-situ and ex-situ tests,
involving a variety of disciplines and multiple steps to compile a range of diagnostic tools, as well as data
acquisition and analysis equipment, which can be adopted to the SOFC technology. This has merit, but
requires extensive cooperation between all involved throughout all the stages of the product development.
These measurement tools will enable analysis of degradation mechanics leading to development of
prognostic tools that can be used to analyze fuel cells and balance of plant (BOP) systems during research
and development, subsequently minimizing operating costs and enhancing overall system efficiency.

v
Acronyms and Abbreviations


ac Alternating
current
AE Acoustic
emission
AlN Aluminum
nitride
AMPS
Affordable Manufacturer of Power Systems
ANL
Argonne National Laboratory
ART
Advanced Refractory Technologies, Inc.
ASR Area
specific
resistance
BOP
Balance of plant
C Celsius
CARS
Coherent Anti-Stokes Raman Spectroscopy
CEPCO
Chubu Electric Power Company, Inc.
CFCL Ceramic
fuel
cells
dc Direct
current
DIGIMAPS
Digital Ordnance Survey Maps
DIN
Departmental Identification Number
dp
Differential
pressure

E
Ideal equilibrium potential
E
°
Ideal standard potential
EC European
Commission
EDAX
Energy dispersive analysis of X-rays
EMF Electromotive
force
EQP Equipotential
ESPI
Electronic Speckle Pattern Interferometry
EU European
Union
FTIR
Fourier Transform Infrared Spectroscopy
GC Gas
chromatography
GT Gas
turbine
hf High
frequency
IEA International
Energy
Agency
IP-SOFC Integrated
Planar-SOFC
IRS
Interscience radial flow
IS Impedance
Spectroscopy
i
sc
Short
circuit
current
ISO International
Standards
Organization
kW Kilowatt
kJ
Kilojoule
LDA
Laser Doppler Anemometry
lf Low
frequency
LHV
Lower heating value
LOCO-SOFC Low Cost Fabrication-SOFC

vi
LSC
Lanthanum strontium cobaltite
LSCF
Lanthanum strontium cobalt iron
LSM
Lanthanum strontium magnesium oxide
LVDT
Linear variable displacement transformer
MCFC
Molten carbonate fuel cell
MEA
Membrane electrode assemblies
MF Multifunctional
MHI
Mitsubishi Heavy Industries
MOLB
Mono Block Layer Built design
MPa Megapascal
MTI
McDermott Technology, Inc.
mV Millivolts
MW Megawatt
NETL
National Energy Technology Laboratory
OCV
Open circuit voltage
PEFC
Polymer electrolyte fuel cell
PEM
Proton exchange membrane
PEN
Positive electrolyte negative
PIV
Particle Image Velocimetry
PNNL
Pacific Northwest National Laboratory
pSOFC Planar
SOFC
Pt Platinum
R&D
Research and development
R
p

Electrode polarization resistance
RE Reference
electrode
Rh Rhodium
RR Rolls
Royce
R
s
Ohmic
resistance
RT Room
temperature
sccg Sub-critical
crack

growth
SECA
Solid State Energy Conversion Alliance
SEM
Scanning electron microscope
SOFC
Solid oxide fuel cells
T Temperature
TMI Technology
Management
Inc.
UMR
University of Missouri (Rolla)
XRD X-ray
diffraction
YSZ
Yttria stabilized zirconia


vii

Acknowledgement



The author would like to acknowledge the invaluable assistance of the Don Jarrell, and Leonard Bond,
Pacific Northwest National Laboratory, who contributed time, expertise and ideas toward the successful
completion of this report. A