Introduction to Polymer Electrolyte Fuel Cell Systems

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Introduction to Polymer Electrolyte Fuel Cell
Systems

• Dr. Krishan Kumar Bhatia
• Mechanical Engineering
• Rowan University
• February 14, 2005

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Overview

• Introduction
• Current Environmental Situation
• Why Fuel Cells?
• Fuel Cell Fundamentals
• System Applications
• Challenges

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Energy Information Administration/Annual Review
2000
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Energy Information Administration/Annual Review
2000
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Energy Information Administration/Annual Review
2000 1 MBPD 2 Quad BTUs
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EPA 420-R-04-001
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Thus, avoiding the SUV trend and simply keeping
the mix of cars and light trucks at the level it
was in 1989 would have saved 75 times more energy
per year than what has been saved by recycling
plastic and four times more energy than what has
been saved each year by recycling aluminum.
Environmental Science Policy 6 (2003)
175179 Friedland et al.
EPA 420-R-04-001
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• CO2 varied between 200 and 300 ppm (last 160,000
  year)
• CO2 has increased from 280 ppm to 360 ppm in a
  single century
• Predicted to rise to 600 ppm by 2100

Green Power, Los Alamos National Lab,
LA-UR-99-3231
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• Vehicle traffic causes half of all urban smog
  and 90 of the carbon monoxide emissions in the
  US.
• Automotive related air pollution kills twice the
  number of Americans that die in auto accidents,
  and triple the number of homicide victims.
• In 2001, you were 24 times more likely to die
  from air pollution than from a terrorist attack.

General Motors Corporation
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The Debate Energy Use

• Transportation Costs?
• Foreign Oil Dependency?
• Environment (i.e. Global Warming)?
• Our Health and Survival?
• Is Our Current Lifestyle Sustainable?
• (5 world population emitting 20 of the
  greenhouse gases)

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Why Fuel Cells?

• Clean (CO2 and emissions), Flexible, Distributed
  Energy Carrier
• Electricity!
• Generate with Nuclear, PV, Wind!
• Storage Problem in Vehicles
• This is changing

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Why Fuel Cells?

• Conventional Motor
• Fuel ? Heat ? Mechanical (vehicle)
• Mechanical Power ? Electricity (coal plant)
• 20 - 30 Fuel ? Electricity
• Fuel Cell Electrochemical Device
• Fuel (hydrogen) ? Electricity (power plant)
• Electricity ? Mechanical Power (vehicle)
• Steady Flow Battery

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Why Fuel Cells?

• Fossil Fuel Dependant ? CO2
• Hydrocarbon Reforming for Hydrogen
• Electrolysis? (only if you have clean e-)
• Well to Wheel studies by Stodolsky et al., Mizey
  et al., and Rousseau et al. (15 ? 40, so CO2
  reduction)
• Single Point Emissions

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Why Fuel Cells?

• Without clean e-, fuel cells DO NOT solve the CO2
  problem, but they can help alleviate it through
  higher efficiencies
• Fuel cells DO shift non-CO2 emissions to single
  point sources

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Why Fuel Cells?

• Fuel cell easily converts H2 to e-
• Fuel cells, through H2 energy carrier, get around
  the on-board e- storage issue.
• Double onboard e- storage ? fuel cells may not
  make sense

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Overview

• Introduction
• Current Environmental Situation
• Why Fuel Cells?
• Fuel Cell Fundamentals
• System Applications
• Challenges

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Fuel Cells Fundamentals

• Electrochemical Device
• Steady Flow Battery
• Electrochemical Engine
• Generate DC power
• of cells (voltage) and active area (current)

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Ballard Corporation
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California Fuel Cell Partnership
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• Teflon Backbone (Hydrophobic)
• Side Chain (Hydrophilic)
• Sulfonic Group (weak, dilute acid)
• Solid Polymer Electrolyte

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Fundamentals
Videal 1.48 V per cell at STP
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Introduction
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Fuel Cell Voltage
Cell Ohmic Resistance
Anode and Cathode Overpotential Loses
Open Circuit Voltage (No Current, Max Voltage
-Internal Current)
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Maximum Open Circuit Voltage
at 80C
Can use Nernst Equation for variations from STP
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Butler-Volmer Equation
Anode Reaction
Cathode Reaction
Bard, A., Faulkner, L., Electrochemical Methods,
Ch. 3, Wiley, 2001.
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Butler-Volmer Equation
Bard, A., Faulkner, L., Electrochemical Methods,
Ch. 3, Wiley, 2001.
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Butler-Volmer Equation General
2 B-V equations for a fuel cell! (one for anode
and one cathode, but same i value) If more than
one electron transferred, multiply exponent by z.
Bard, A., Faulkner, L., Electrochemical Methods,
Ch. 3, Wiley, 2001.
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Butler-Volmer Equation No Mass Transfer
If alpha 0.5,
Bard, A., Faulkner, L., Electrochemical Methods,
Ch. 3, Wiley, 2001.
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Butler-Volmer Equation Tafel Kinetics
Assume no mass transfer limitation, and cathode
reaction is very slow
Assume cathode overpotential is large
Bard, A., Faulkner, L., Electrochemical Methods,
Ch. 3, Wiley, 2001.
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Tafel Equation
Bard, A., Faulkner, L., Electrochemical Methods,
Ch. 3, Wiley, 2001.
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Introduction
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Overview

• Introduction
• Current Environmental Situation
• Why Fuel Cells?
• Fuel Cell Fundamentals
• System Applications
• Challenges

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Green Power, Los Alamos National Lab,
LA-UR-99-3231
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• FCV
• Entire Drive System Contained in Skateboard
• Interchangeable, Bolt on Body

• Single Center Electrical Connection
• Drive By Wire (Steering, Accelerator, Braking,
  etc.)

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Honda Motor Company
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Ocean County College, Toms River, NJ
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Overview

• Introduction
• Current Environmental Situation
• Why Fuel Cells?
• Fuel Cell Fundamentals
• System Applications
• Challenges

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Challenges

• Cold Start
• Hydrogen Storage
• High Pressure Composite Tanks
• Cryogenic Storage
• On-board Hydrocarbon Reforming?
• Carbon Monoxide Poisoning

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100 H2, 100 ppm CO
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Challenges

• Durability (up to 5,000 hrs and 40,000 hrs?)
• Clean H2 Production
• Cost per kW (not just Pt)
• Size
• Weight
• End of Cycle Impact?
• Better than Hybrid Technology?
• Better than EV Technology?

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• A.D. Little study projects high volume
  production cost of 14,700 or 294/kW (60 Stack,
  29 Processor, 11 BOP, Assembly, and Indirect)
  for fuel cell system
• Platinum cost alone is 63/kW (21 of total )
• ICE engine cost?
• Fuel Cell Vehicle cell, auxiliary equipment, H2
  storage, power inverters, and electric motors

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Comparative Study Automotive
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CURRENT SCIENCE, VOL. 77, NO. 9, 10 NOVEMBER
1999
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Honda Motor Company
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• 1 Liter displacement
• 2.0 kW/kg (145lbs?180hp)
• lt 20/kW

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• Solutions are very tough, but changing our
  individual lifestyle is relatively easy
• It is extremely difficult to double the energy
  efficiency of cars and cut their emissions in
  half. -Dr. Bhatia
• Why dont you ride with a friend to work? -
  7th grader at Susquehanna Township Middle
  School, Harrisburg, PA

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• Questions