Frano Barbir Pictorial Resume. energy partners

Frano Barbir Pictorial Resume energy partners

Diagnostic(s) noun the art or practice of diagnosis Diagnosis noun Investigation or analysis of the cause or nature of a condition, situation or problem

Diagnostics in fuel cell development process

requirements design Knowledge: materials processes interactions model fabricate Should it work? test Does it work? diagnostics

Diagnostics in fuel cell development process Diagnostics in control development process

Diagnostics in fuel cell development process Diagnostics in control development process Diagnostics in operation

disturbances control element manipulated variable fuel cell process variable controller output signal measured value controller error set point measured process variable signal measurement sensor/ transmitter

Observe (voltage/current, pressure drop, temperature) 1 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0 0 20 40 60 80 100 120

Observe (voltage/current, pressure drop, temperature) Change a parameter and compare

First fuel cell law: One cannot change only one parameter in a fuel cell change of one parameter causes a change in at least two other parameters, and at least one of them has an opposite effect of the one expected to be seen. F. Barbir, PEM Fuel Cells Theory and Practice, Elsevier/Academic Press, 2005

Fuel cells: Problems at different scales m mm m nm 12700 km 12.7 km 12.7 m 12.7 mm

Observe (voltage/current, pressure drop, temperature) Change a parameter and compare Disturb and observe Small disturbances Large disturbances (exaggerate or accelerate)

disturbances control element(s) manipulated variable(s) fuel cell process variable(s) controller output signal(s) controller controller action signal diagnostics measured values diagnosis desired/expected state of health

Diagnostics in fuel cell development process Diagnostics in control development process Diagnostics in operation Post mortem diagnostics

Online Offline Post mortem

Electrochemical techniques Polarization curve Current interruption Electrochemical Impedance Spectroscopy Cyclic Voltammetry CO Stripping Voltammetry Linear Sweep Voltammetry Species Distribution Mapping Pressure Drop Measurements Gas Composition Analysis Neutron Imaging Magnetic Resonance Imaging X-ray Imaging Optically Transparent Fuel Cells Embedded Sensors Current Distribution Mapping Partial MEA Segmented Cells Temperature Distribution Mapping IR Transparent Fuel Cells Embedded Sensors

Polarization curve Polarization curve hysteresis Comparative polarization curves Current interrupt AC impedance spectroscopy Pressure drop Current density mapping Temperature mapping Flow visualization Neutron/X-Ray imaging

cell potential (V) 1.2 1 theoretical (ideal) voltage activation losses 0.8 0.6 resistance losses 0.4 0.2 resulting V vs. i curve mass transport losses 0 0 500 1000 1500 2000 current density (ma/cm²)

cell potential (V) 1.2 1 0.8 0.6 0.4 0.2 0 higher resistance drying? mass transport problems flooding? normal polarization curve 0 500 1000 1500 2000 current density (ma/cm²) hgher activation losses

Data should be taken at multiple current or voltage points. Typical points would be open circuit and 5 or 6 points between 600 mv/cell and 850 mv/cell, 15 minutes dwell at each point The data from the last five (5) minutes should be averaged and then plotted as average current versus average voltage. Protocol on Fuel Cell Components Testing

Polarization curve sweep

Qiangu Yan, J. Power Sources, Vol 161, 2006, pp 492 502

Cell Voltage/Differential Pressure Static Feed UNIGEN Cycle Test (Total 8/1/03 3:00 PM - 147 cycles) Electrolysis: 60 min @ 200 ASF; Fuel Cell: 40 min @ 300 ASF > 100 LEO cycles 160 F, 50-75 psig 2.50 2.30 2.10 1.90 1.70 1.50 1.30 Fuel Cell 40 min Electrolysis 60 min 1.10 0.90 0.70 0.50 50.00 50.50 51.00 51.50 52.00 52.50 53.00 53.50 54.00 54.50 55.00 Elapsed Time (hr) Presented at IECEC, Portsmouth, VA, August 12, 2003

M. Weiland, Int. J. Hydrogen Energy, 2012, in print

c e ll p o te n tia l ( V ) 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0 200 400 600 800 1000 current density (ma/cm²) Polarization curve at cell temperature 80 C anode/cathode humidifier temperatures 80/60 C hydrogen/air, 30 psig, H2 stoich 1.5, air stoich 5.0

Source: T.P. Ralph and M.P. Hogarth, Platinum Metals Review, Vol. 46, No. 1, pp. 3-14, 2002

Current interrupt method for measurement of fuel cell resistance Fuel cell Load Digital osciloscope A voltage OCV Slow rise to OCV V act Cell voltage before current interrupt Immediate rise in voltage, V R Time of current interrupt time

Current interrupt method for measurement of fuel cell resistance extrapolated straight lines OCV discrete points voltage ringing effect Cell voltage before current interrupt Immediate rise in voltage, V R Time of current interrupt time

Nyquist and Bode plots

R HF Resistance

Cell Potential (Volts), Resistance (miliohm-cm 2 ), Pressure Drop(10 kpa) Temperature ( o C) 80 0.7 Cell Voltage 70 0.6 Stack Temperature 60 0.5 50 0.4 Pressure Drop Humidification Temperature 40 0.3 30 Resistance 0.2 20 2000 2500 3000 3500 4000 4500 5000 Time (seconds)

Cell Potential (Volts), Resistance (miliohm-cm 2 ), Pressure Drop (10 kpa) Temperature ( o C) 80 0.7 Stack Temperature 0.6 0.5 Humidification Temperature Cell Voltage 60 0.4 Pressure Drop 40 0.3 Resistance 0.2 20 10000 10500 11000 11500 12000 12500 Time (seconds)

S.J.C. Cleghorn, C.R. Derouin, M.S. Wilson, and S. Gottesfeld, A Printed Circuit Board Approach to Measuring Current Distribution in a Fuel Cell, J. Appl. Electrochem., 1997

local current density measurement dynamic > 2000 measurement /s L o k a l e M e s s u n g e n local temperature measurement local electrochemical impedance spectroscopy (EIS) 4 mm

D. Derteisen et al., Int. J. Hydrogen Energy, Vol 37, 2012, pp. 7736 7744

ir camera

Temperature Mapping with ir Camera

smallest sensor on the market Sensirion SHT 71

Interdigitated Flow Field Straight Channels X Liu, et al. Water flooding and twophase flow in cathode channels of proton exchange membrane fuel cells, Journal of Power Sources,

D. Lee, J. Bae, Visualization of flooding in a single cell and stacks by using a newlydesigned transparent PEMFC International Journal of Hydrogen Energy, Vol. 37, No.1, 2012, pp 422 435

S Basu et al., J Power Sources, Vol 162, 2006, pp 286 293

K Takada et al. J. Power Sources, Vol 196, 2011, Pages 2635 2639 Inukai, J. et al. Direct Visualization of Oxygen Distribution in Operating Fuel Cells. Angew. Chem. Int. Ed. 47, 2792 2795 (2008).

Real time detection of liquid water inside an operating fuel cell

at Penn State University A. Turhan, K. Heller, J.S. Brenizer and M.M. Mench, Passive control of liquid water storage and distribution in a PEFC through flow-field design, Journal of Power Sources 180 (2) (2008), pp. 773 783.

H. Markötter et al., Int. J. Hydrogen Energy, Vol 37, 2012, pp. 7757 7761

P. Deevanhxay, Electrochemistry Comm., 2012 http://dx.doi.org/10.1016/j.elecom.2012.05.028,

Conclusions Diagnostics important aspect of fuel cell R&D Limited number of diagnostic methods applicable for fuel cell control purposes Definition of optimum performance must include life time In order to achieve optimum performance diagnostics is crucial for prognostics and health management

More information about PEM fuel cells: Frano Barbir PEM Fuel Cells: Theory and Practice Elsevier/Academic Press, 2005 ISBN 978-0-12-078142-3 PEM Fuel Cells: Theory and Practice Written as a textbook for engineering students. Used at hundreds of universities In U.S., China, India, Korea, Iran, Germany, Croatia New updated edition coming out 2012! Available from: www.elsevier.com www.amazon.com www.barnesandnoble.com