Hydrogen Fuel Cell

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Hydrogen Fuel Cell
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Trends in the use of fuel
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(No Transcript)
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The History of Fuel Cells
Electrolyser
Groves Gas Battery
(first fuel cell, 1839)
(after Larminie and Dicks, 2000)
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Photo courtesy of University of Cambridge
Bacons laboratory in 1955
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Photo courtesy of NASA
NASA Space Shuttle fuel cell
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Applications for Fuel Cells
Transportation vehicles

Photo courtesy of DaimlerChrysler
NECAR 5
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Applications for Fuel Cells
Distributed power stations
Photo courtesy of Ballard Power Systems
250 kW distributed cogeneration power plant
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Applications for Fuel Cells
Home power
Photo courtesy of Plug Power
7 kW home cogeneration power plant
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Applications for Fuel Cells
Portable power
50 W portable fuel cell with metal hydride storage
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The Science of Fuel Cells
Alkaline(AFC)
Polymer Electrolyte Membrane (PEMFC)
Phosphoric Acid(PAFC)
Polymer Electrolyte Membrane(PEMFC)
Types of Fuel Cells
Molten Carbonate(MCFC)
Direct Methanol (DMFC)
Direct Methanol(DMFC)
Solid Oxide (SOFC)
Solid Oxide(SOFC)
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PEM Fuel Cell Electrochemical Reactions
Anode H2 2H 2e- (oxidation) Cathode
1/2 O2 2e- 2H H2O (l)
(reduction) Overall Reaction H2 1/2 02
H2O (l) ?H - 285.8 kJ/mole
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A Simple PEM Fuel Cell
Hydrogen Oxygen ? Electricity Water
Water
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Membrane Electrode Assembly (MEA)
C
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Oxidation
-
4
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Platinum- catalyst
T
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H
2
2
H

2
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Reduction

Platinum- catalyst
H
Anode
K
Cathode
-
-
4
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4
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O
O
Polymer electrolyte (i.e. Nafion)
2
2
N
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4
H
4
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Carbon cloth
Carbon cloth
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2
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2
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2
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Polymer Electrolyte Membrane
Polytetrafluoroethylene (PTFE) chains
Water collects around the clusters of hydrophylic
sulphonate side chains
Sulphonic Acid
50-175 microns
(2-7 sheets of paper)
(after Larminie and Dicks, 2000)
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Thermodynamics of PEM Fuel Cells
Change in enthalpy (?H) - 285,800
J/mole Gibbs free energy (?G) ?H - T?S ?G at
25 C - 285,800 J - (298K)(-163.2J/K)
- 237,200 J Ideal cell voltage (? E) -
?G/(nF) ?E at 25º C - -237,200
J/((2)(96,487 J/V)) 1.23 V ?G at
operating temperature (80º C) - 285,800 J -
(353K)(163.2 J/K) - 228,200 J ?E at 80º
C - -228,200 J/((2)(96,487 J/V))
1.18 V
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Characteristic Curve
Power Curve
activation losses internal currents
1.2
MPP
2.5
ohmic losses
1
x
concentration losses
2
0.8
1.5
P
0.6
V
1
0.4
0.5
0.2
0
0
0
1
2
3
4
0
1
2
3
4
5
I
I
Max Power Point (MPP)

• Factors affecting Curve
• activation losses
• fuel crossover and internal currents
• ohmic losses
• mass transport or concentration losses

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Hydrogen Storage
56 l
14 l
9.9 l
Compressed gas (200 bar)
Liquid hydrogen
MgH2 metal hydride
Liters to store 1 kg hydrogen
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Hydrogen Energy Forever
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Renewable Energy Sources
As long as the sun shines, the wind blows or the
rivers flow there can be clean, safe and
sustainable electrical power, where and when
required, with a solar hydrogen energy system
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The Benefits of Fuel Cells
Clean
Modular
Quiet
Benefits of Fuel Cells
Safe
Sustainable
Efficient
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Our Fragile Planet. We have the responsibility to
mind the planet, so that the extraordinary
natural beauty of the Earth is preserved for
generations to come.
Photo courtesy of NASA
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Presentation courtesy of Heliocentris