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PhD defense

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by

Samuel Simon Araya

on 21 April 2015

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Transcript of PhD defense

Why fuel cells?
What is a fuel cell?
1st step
2nd step
Last step
Test Station for EIS characterization
Electrochemical Impedance Spectroscopy (EIS)
Why Characterization?
Characterization of High Temperature PEM Fuel Cells
Oral presentation for a PhD Candidacy
by
Samuel Simon Araya
ssa@et.aau.dk
Supervisors: Søren Knudsen Kær
and Søren Juhl Andreasen
3.2% increase in 2011 alone
2020-2050 targets
HT-PEM fuel cell
FC
Bubbler system
Evaporator System
Test setup
Results
Effects of CO
Effects of CO
Effects of methanol-water vapor mixture
Conlusions
Combined Effects of all reformate impurities
Thank you for your attention
EC
FC
Storage
Plug-in EV
FCEV
By 2020: 50% Wind
By 2035: 100% household demands to be met by renewable sources of energy
By 2050: 100% fossil fuel free, including transportation and industry
2H
+ 2e-
H
2
+
2H
+ 2e-
1/2O
2
+
+
H
2
O
State of the art and trends
Transportation
PV
Hyundai has announced that it will offer a fuel-cell version of its ix35 sport utility vehicle (known as the Tucson in the U.S.) on lease by the end of this year. It plans to make up to 1,000 fuel-cell cars by 2015 and thereafter 10,000 fuel-cell cars per year. - CNN

Toyota, Honda, Daimler, GM and other major auto-companies on similar tracks, to start mass production by 2015 - DOE
Stationary
Portable
APUs
Methanol fueled battery chargers
toys
Educational fuel cells
A number of fuel cell patents for portable devices have been filed by Samsung and Apple
I(t)
V(t)
Phase shift
Source: Jesper Lebæk [2010]
-0.005

mV/h
-0.9 mV/h
-3.4 mV/h
"Fuel cells have never been in a better position to positively impact our everyday lives and enjoy the commercial success promised for so long."
- Fuel Cell Today
Future work
EIS can give better understanding of some processes, including the loss of ECSA, if coupled with other techniques, such as CV and microscopy, which we did but more test could give better understanding

Even though we isolated the effects of methanol-water vapor mixture from the gaseous species, it would be helpful to also isolate the effects of methanol-from those of water

Start/stop and other cycling tests in the presence of methanol-water vapor mixture can be done to see if the PA leaching becomes severe

All the tests can be extended to stack level since the experiences can be different
Publications
1. Vapor Delivery Systems for the Study of the Effects of Reformate Gas Impurities in HT-PEM Fuel Cells
Simon Araya, Samuel
; Kær, Søren Knudsen; Andreasen, Søren Juhl.
Published in the Journal of Fuel Cell Science and Technology, 2012
2. Characterization of the Poisoning Effects of Reformate Impurities in a High Temperature PEM Fuel Cell
Simon Araya, Samuel
; Andreasen, Søren Juhl; Kær, Søren Knudsen.
Published in Energies in special issue: Hydrogen Energy and Fuel Cells, 2012
3. Investigating the Effects of Methanol-Water Vapor Mixture on a PBI-BasedHigh Temperature PEM Fuel Cell
Simon Araya, Samuel
; Andreasen, Søren Juhl; Nielsen, Heidi Venstrup; Kær, Søren Knudsen.
Published in International Journal of Hydrogen Energy, 2012
4. EIS Characterization of the Poisoning Effects of CO and CO2 on a PB Based HT-PEM Fuel Cell
Andreasen, Søren Juhl; Mosbæk, Rasmus; Vang, Jakob Rabjerg; Kær, Søren Knudsen;
Simon Araya, Samuel
.
Published In ASME Conference Proceedings, 2010
CH3OH + Pt --> Pt-CO + 4H+ + 4e-
2
Ohmic resistance
High frequency
Intermediate-low frequency
The effects of temperature and methanol-based reformate impurities were tested
An in house prepared complete single cells test station was used for all the characterizations
All the impurities cause degradation to some degree, including methanol-water vapor mixture
Most of the degradations are more pronounced at intermediate-high frequency, implying charge transfer losses due to loss in ECSA.
The degradations are a mix of both reversible and irreversible, with the effects of methanol being partially reversible
SEM images showed a small Pt agglomeration and PA mobility
There is interaction among the effects of the impurities mainly between CO and CO2, at high CO concentrations
FC
FC
FC
Full transcript