Fuel Cells: Basics and Applications

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Fuel Cells Basics and ApplicationsHow do fuel
cell cars work?
Ajay K. Prasad Professor, Department of
Mechanical Engineering Director, Center for Fuel
Cell Research University of Delaware prasad_at_udel.
edu
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What is a Fuel Cell?

• A fuel cell combines fuel and oxidant
  electrochemically to produce electricity
• Two to three times more efficient that an
  internal combustion engine
• Fuel cell stack is quiet, has no moving parts,
  produces zero emissions

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PEM fuel cell stack
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Automotive fuel cells (PEM)
Honda FCX Clarity
GMs skateboard chassis idea.
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Mercedes-Benz Citaro fuel cell bus on the
streets of London. Engine supplied by
Ballard. European Fuel Cell Bus Project, which
saw 30 fuel cell buses operating on the roads of
Europe over the past two years.
Toyota The FCHV-BUS2 is a large, low-floor,
fuel-cell hybrid bus. Since its exhaust is free
of NOx (nitrogen oxides) and PM (particulate
matter), it can help improve air quality in urban
areas.
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Fuel cells for portable power (DMFC)
Casio World's smallest fuel cell for use in
laptop PC. The polymer electrolyte fuel can
power a typical laptop computer for eight to 16
hours.
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Fuel cells for stationary power (SOFC)
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Pros and Cons of Fuel Cells
Advantages of Fuel Cells 1. Higher efficiency compared to IC engines
Advantages of Fuel Cells 2. Zero emissions at the point-of-use
Advantages of Fuel Cells 3. No moving parts in the stack, so quieter
Challenges Facing Fuel Cells 1. Cost (materials, labor, economy of scale)
Challenges Facing Fuel Cells 2. Durability (membrane, catalyst)
Challenges Facing Fuel Cells 3. Lack of H2 Infrastructure H2 is difficult to produce, transport, and store
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UD Fuel Cell Hybrid Bus Program

• UD Fuel Cell Bus Program 2005-2011
• Phase 1 22-ft bus, 20 kW stack, Ni-Cad
  batteries (in operation, 100 students/day)
• Phase 2 22-ft bus, 40 kW stack, Ni-Cadbatteries
  (Spring 09)
• Phase 3 30-ft bus, 40 kW stack, Li-Ti batteries
  (2010)
• Phase 4 30-ft bus, 40 kW stack, Li-Ti batteries
  (2011)

• H2 refueling station in Newark since 2007
• Two more H2 stations in Wilmington and Dover

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How do fuel cell cars work?

• Components of a fuel cell car
• Fuel cell stack
• Balance of plant Air compressor, hydrogen
  recirculating pump, air and hydrogen humidifiers,
  coolant pump and radiator
• Hydrogen storage tank
• Battery for hybrid operation
• Boost converter and inverter
• Traction motor and transmission
• Computer for control and management

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Schematic of direct-hydrogen pressurized FCS
R.K. Ahluwalia et al. / Journal of Power Sources
152 (2005) 233244
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Schematic of electric drive train for FCHEV
R.K. Ahluwalia et al. / Journal of Power Sources
152 (2005) 233244
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Energy Flow within components for FCHEV
Energy flow within the components of FCHEV for
FUDS FCHEV with 65kWe FCS and 55kWe ESS. R.K.
Ahluwalia et al. / Journal of Power Sources 152
(2005) 233244
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Requirements for FCHEV

• To be competitive with the conventional ICE
  propulsion system in terms of drivability and
  performance, the FCS must satisfy the following
  requirements
• FCS alone must meet vehicle power demands under
  all driving conditions Top sustained speed of
  100 mph, and 55 mph at 6.5 grade for 20 min.
• With the assistance of ESS, the FCS must allow 0
  to 60 mph in 10 s.
• 1 s transient response time for 1090 power.
• FCS must reach maximum power in 15 s for cold
  start from 20 ?C ambient temperature, and in 30 s
  from -20 ?C ambient temperature.

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Series and Parallel Hybrid Fuel Cell Vehicles

• Series Hybrid
• Small fuel cell, large battery bank
• Battery drives motor at all times
• Fuel cell operates continuously and keeps battery
  charged
• Fuel cell is not load-following

• Parallel Hybrid
• Large fuel cell, small battery bank
• Fuel cell drives motor at all times, it is
  load-following
• Battery provides boost power as and when required

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The Honda FCX Clarity
Engine 100 kW, 57 liters, 148 lb Fuel economy
74 mpgge Range 280 miles H2 Storage 4.1 kg
at 5000 psi