Hydrogen Utilization - Fuel Cell

1
Hydrogen Utilization - Fuel Cell

• Shou-Shing Hsieh
• Department of Mechanical and Electro-Mechanical
  Engineering
• National Sun Yat-Sen University
• Kaohsiung,Taiwan
• February 26, 2006

2
Items

• What is energy?
• Kyoto Protocol
• Hydrogen Energy
• Fuel Cell
• Types of Fuel Cell
• Micro Fuel Cell
• Experimental Results
• Fuel Cell Stack Design
• Conclusions
• References

S.S. Hsieh ppt. 01
3
What is energy ?
The capacity for doing work as measured by the
capability of doing work (potential energy) or
the conversion of this capability to motion
(kinetic energy).
Most of the world's convertible energy comes from
fossil fuels that are burned to produce heat that
is then used as a transfer medium to mechanical or
other means in order to accomplish tasks.
S.S. Hsieh ppt. 02
4
Types of Energy

• Coal
• Oil Natural Gas
• Nuclear
• Geothermal
• Solar
• Hydro power
• Wind
• Biomass
• Fuel cells (Hydrogen Energy )

S.S. Hsieh ppt. 03
5
Energy Crisis
If we continue to consume energy on such a
scale , we may face a petroleum shortage in the
latter half of the 21st century, according to
some predictions. Though nobody is certain how
much petroleum is left
, one thing is certain - at some point we will
run out.
Because people used a large number of the fossil
fuel, discharge the carbon dioxide in a large
amount. These then cause global warming and,
consequently
, influence the human ecology.
S.S. Hsieh ppt. 04
6
Kyoto Protocol
The Kyoto Protocol is a legally binding agreement
under which industrialized countries will reduce
their collective emissions of greenhouse gases by
5.2 compared to the year 1990. The goal is to
lower
emissions from six greenhouse gases.
S.S. Hsieh ppt. 05
7
Hydrogen Energy
Hydrogen is a chemical element that carries
energy. It can be stored in either liquid or
gaseous form. Today, hydrogen is not a substance
we consciously encounter in everyday life,
although it is used
extensively in many industries.
It is normally bound to other substances, it is
colourless, odourless, non-toxic and when it
burns in
air, that reaction produces only water.
S.S. Hsieh ppt. 06
8
Hydrogen Energy (continued)
Besides the fuel of boiler and steam turbine, the
hydrogen can often be used to the fuel cell to
generate electricity most directly, because it
actually
generates electricity efficiency up to 4060.
S.S. Hsieh ppt. 07
9
Hydrogen Applications

• The applications of hydrogen energy are
  following
• As the fuel of the fuel cell
• As the fuel of family
• As the fuel of the vehicle engine or the energy
  of the
• electronic device
• As the fuel of the aircraft
• As the materials of the chemical industry
• As the fuel of the boiler and steam turbine

S.S. Hsieh ppt. 08
10
Hydrogen Fuel Stations

• Hydrogen Fuel Stations Worldwide accumulated,
  sorted by region (1995-2004)

S.S. Hsieh ppt. 09
11
Hydrogen for Fuel Cell
The electrons flow from the fuel cell's anode to
cathode, thereby generating electricity.
Meanwhile , the hydrogen atoms that have shed
their electrons become hydrogen ions and travel
through a polymer electrolyte membrane to reach
the cathode side. There, with the help of a
catalyst on the cathode, the hydrogen ions and
electrons join with oxygen to form
water.
S.S. Hsieh ppt. 10
12
Fuel Cell
Fuel cell is a device that converts the chemical
energy of a fuel and an oxidant directly into
electricity. The principal components of a fuel
cell include electrodes (anode and cathode), and
membrane-
electrode assembly (MEA).
Fuel cell stacks available and under development
are silent, produce no pollutants, have no moving
parts , and have potential fuel efficiencies far
beyond the most advanced reciprocating engine or
gas turbine
power generation systems.
S.S. Hsieh ppt. 11
13
Fuel Cell ( continued )

• A Traditional Design of PEMFC

S.S. Hsieh ppt. 12
14
Fuel Cell ( continued )

• High efficiency to produce energy

LHV lower heating
value.
A thermodynamic term that indicates the heat
needed to raise steam
from liquid water.
(From http//www.broadcastpapers.com/m )
S.S. Hsieh ppt. 13
15
Fuel Cell Advantages

• Working time is longer than the traditional
  batteries
• It can offer energy for a long time when the
  hydrogen supply with.
• Short time in supplement fuel process
• After the fuel is used up, then It can run
  once again if we supply
• the hydrogen constantly.
• Clean in the energy production process
• The products are only water and heat.

S.S. Hsieh ppt. 14
16
Types of Fuel Cell
Fuel Cell Type Electrolyte Anode Gas Cathode Gas Temperature Efficiency
Proton Exchange Membrane ( PEMFC ) solid polymer membrane hydrogen pure or atmospheric oxygen 75OC ( 180OF ) 35-60
Alkaline ( AFC ) potassium hydroxide hydrogen pure oxygen below 80OC 50-70
Direct Methanol ( DMFC ) solid polymer membrane methanol solution in water atmospheric oxygen 75OC ( 180OF ) 35-40
Phosphoric Acid ( PAFC ) Phosphorous hydrogen atmospheric oxygen 200OC ( 400OF ) 35-50
Molten Carbonate ( MCFC ) Alkali - Carbonates hydrogen, methane atmospheric oxygen 650OC ( 1200OF ) 40-55
Solid Oxide ( SOFC ) Ceramic Oxide hydrogen, methane atmospheric oxygen 800-1000OC ( 1500-1800OF ) 45-60
S.S. Hsieh ppt. 15
17
PEMFC
Anode Reaction
Cathode Reaction
Total Reaction
Ideal Voltage
1.23V
( From http//fuelcellsworks.com )
S.S. Hsieh ppt. 16
18
PEMFC (continued)
This type of fuel cell operates at low
temperatures (75OC), and has a high power output
density, and
can vary output to meet demand.
It is suitable for use in light-duty vehicles,
buildings , cell phones, and as replacements for
small
rechargeable batteries.
S.S. Hsieh ppt. 17
19
AFC
Anode Reaction
Cathode Reaction
Total Reaction
( From http//www.fuelcellcontrol.com )
S.S. Hsieh ppt. 18
20
AFC (continued)
Alkali fuel cells (AFC) use a concentrated
solution of potassium hydroxide (KOH) in water as
an electrolyte. Hydroxyl ions ( ) migrate from
the cathode to the anode in these fuel cells.
Hydrogen gas supplied to the anode reacts with
the ions to produce water. The reaction
releases electrons , which provide the electrical
power. And AFC are 60
percent efficient.
S.S. Hsieh ppt. 19
21
DMFC
Anode Reaction
Cathode Reaction
Total Reaction
Ideal Voltage
1.18V
S.S. Hsieh ppt. 20
22
DMFC (continued)
The DMFC draws hydrogen from the methanol
directly at operating temperatures of 50-100OC.
It is suitable for applications such as cell
phones and
laptop computers.
S.S. Hsieh ppt. 21
23
PAFC
Anode Reaction
Cathode Reaction
Total Reaction
(From http//www.brennstoffzelle-koeln.de/Pages)
S.S. Hsieh ppt. 22
24
PAFC (continued)
This type of fuel cell operates at high
temperatures (150 200OC) to maintain the ionic
conductivity of phosphoric acid. It generates
electricity at 40 efficiency (80 if the steam
produced is used for cogeneration) and can use
impure hydrogen as fuel.
S.S. Hsieh ppt. 23
25
MCFC
Anode Reaction
Cathode Reaction
Total Reaction
( From http//fuelcellsworks.com)
S.S. Hsieh ppt. 24
26
MCFC (continued)
MCFC are expected to achieve power efficiencies
of 60 (85 with cogeneration) and operate at
very high temperatures (650OC) to maintain
electrolyte conductivity. This type of
fuel cell is suitable for large electric utility
applications.
S.S. Hsieh ppt. 25
27
SOFC
Anode Reaction
Cathode Reaction
Total Reaction
( From http//fuelcellsworks.com )
S.S. Hsieh ppt. 26
28
SOFC (continued)
This type of fuel cell is suitable for large,
high-power applications such as industrial or
electricity generators. Its operating
temperatures is 1000OC, and it is expected to
achieve power efficiencies of 60 (85 with
cogeneration).
S.S. Hsieh ppt. 27
29
Fuel Cell Trends
S.S. Hsieh ppt. 28
30
Fuel Cell Comparison
Fuel Cell Type Advantage Fault Application
PEMFC ? Operate at low temperatures ? Proven long operating ? Have fast starup time ? Have high power densities ? Additional humidification ? A platinum catalyst is expensive ? Household electrical generation ? Light-duty transportation
DMFC ? The fuel storage problems is easy ? Methanol is easier to transport and supply ? Slow starup time ? Methanol crossover ? Expensive ? Cellular phones ? Laptops ? Remote power ? Transportation
SOFC ? Can make fuel with the natural gas or the methane ? Can make oxidizer with air ? Operate at high temperature ? Electrical generators ? Large power plant ? Industrial power supplies
S.S. Hsieh ppt. 29
31
Micro Fuel Cell

• Applications

Distinctive, high density energy sources for
portable products Hybrid battery
rechargers separate (desktop) Portable
Electronics radio, PDA, laptop, cellular
phone, portable power source
S.S. Hsieh ppt. 30
32
Micro Fuel Cell (continued)

• Advantages of Micro PEM Fuel Cells

Small, lightweight Inexpensive(?)
Low (room) temperature operation Unique
multi-layer (ceramic,silicon, etc.)
miniaturization possible
S.S. Hsieh ppt. 31
33
Micro Fuel Cell (continued)

• H2 Proton Exchange Membrane Fuel Cell (H2 PEMFC)

S.S. Hsieh ppt. 32
34
Micro Fuel Cell (continued)

• New Design

Three to one layer design combine current
collector , flow filed plate and backing
layer Microstructure by MEMS fabrication
(a) thin film deposited and layer growth with
surface mount technology (b)
microflow channel by excimer laser processing
S.S. Hsieh ppt. 33
35
Micro Fuel Cell (continued)

• structure

S.S. Hsieh ppt. 34
36
Micro Fuel Cell (continued)

• Advantage of new design

Minimized fuel cells and reduce its weight.
Catalyst (Pt) loading reduced as low as
0.15mg/cm2 (traditional design is
0.4mg/cm2). Flow field plate have a large
effective flow passage even up 20
increase in contact area.
S.S. Hsieh ppt. 35
37
Micro Fuel Cell (continued)

• Gasket
• An acrylic structure to protect and observe
  the fuel cell.
• Flow Field Plate?Current Collector

Serpentine Flow Field
Interdigitated Flow Field
Mesh Flow Field
S.S. Hsieh ppt. 36
38
Micro Fuel Cell (continued)

• Membrane-electrode assembly (MEA)

An assembly consisting of an anode, and
electrolyte, and a cathode (3 layer MEA), and
may include gas diffusion layers.
S.S. Hsieh ppt. 37
39
MEA Morphology
SEM image showing the morphological condition of
thin platinum sputtered on
AFM image showing the morphological condition on
thin platinum (200x200nm2)
Nafion 117 (1.5x1.2µm2)
S.S. Hsieh ppt. 38
40
Micro Fuel Cell
flow-field plate
fuel cell
S.S. Hsieh ppt. 39
41
Experiments
lamp
H2 in
Air in
H2 out
S.S. Hsieh ppt. 40
42
Fuel Cell Polarization
As the fuel cell is operating, the cell
potential decreases from its reversible (ideal)
value for the sake of the irreversible
losses. These losses are often referred as
polarization , which include activation
polarization, concentration polarization,
ohmic polarization.
S.S. Hsieh ppt. 41
43
Fuel Cell Polarization (continued)

• Activation Polarization

It happens in the delayed phenomenon of reactive
speed when fuel cells start the electric
chemical reaction on the electrode surface.

• Ohmic Polarization

It happens on the move of ion in the electrolyte
and the impedance of electron move.

• Concentration Polarization

It happens when the fuel cells dont maintain the
proper concentration of reactant on the
electrode surface.
S.S. Hsieh ppt. 42
44
Experimental Results

S.S. Hsieh ppt. 43
45
Experimental Results (continued)
S.S. Hsieh ppt. 44
46
Stack Design Methods
Fuel cell stack using series is a
conventional method for commercialization,
because we can get high voltage and low current
to drive devices in our life. The methods
of series are following
Conventional Vertical Stack
Planar Flip-Flop Stack
Banded Stack
S.S. Hsieh ppt. 45
47
Stack Design Methods (Continued)

• Conventional Vertical Stack

The conventional vertical stack is a simple
design method to construct a fuel cell stack,
because its principle and experiment test loop
are easier and simpler. But, its volume is huger
than the other design methods.

• Planar Flip-Flop Stack and Banded Stack

The planar flip-flop and banded stack are
advanced methods to construct fuel cell stacks,
because they use conductor to connect other
neighbor single cell. Its advantages are small
volume and packaging flexibility, but using
interconnected conductor methods will cause
potentially higher ohmic loss and difficulty of
ensuring equal reactant distribution to
muiltiple cells in a plane.
S.S. Hsieh ppt. 46
48
Stack Design Methods (Continued)
Fuel cell stack connected in parallel is not
useful for micro fuel cell, because we can not
get high voltage and low current to drive
devices in our life (The parallel method gets low
voltage and high current). The volume of
parallel stack is larger than the series, and
the method is difficulty of ensuring equal
reactant distribution to muiltiple cells. The
method of parallel is following
Surface to Surface Stack
S.S. Hsieh ppt. 47
49
Stack Design Methods (Continued)
In spite of the above-statements in the high
power rate fuel cell using for the power plant,
SOFC, the method is very suitable. Because the
parallel method can avoid short circuit when
there are fuel cells not working in the system.
The method of parallel Is following
The power plant used in parallel and series fuel
cell stack system
S.S. Hsieh ppt. 48
50
Stack Design Goals

• Low resistance connection between cells

Because the force from nut and bolt will increase
the contact resistance in stack fabrication, we
should take care of the effect in fuel cell
design.

• Interconnect must accurately control and
  distribute air and
• fuel flows

If the hydrogen and oxygen dont distribute
equally in each cells, it will cause higher
concentration resistance and decrease stack
performance. So we should take extreme caution
in fuel cell design.

• Fuel losses must be controlled for high fuel
  utilization

Fuel loss will cause the performance decrease, so
we can use UV glue or other packaged materials to
prevent the effect.
S.S. Hsieh ppt. 49
51
Fuel Cell Applications

• Notebook

• Transportation vehicle

Samsung 2004 presents new DMFC notebook. It can
work more than 10
Hondas 2005 FCX fuel cell vehicle it is
powered by a Honda designed and manufactured
fuel cell stack.
hours without recharging.
( From http//www.fuelcelltoday.com )
( From http// www.motorcities.com )
S.S. Hsieh ppt. 50
52
Conclusions
No matter in food, clothing, lives,
transportation , education, amusement, the energy
is closely linked with our life. So on the
premise of no pollution for the environment, it
is a good choice to use the fuel cell to generate
electricity. We can believe that under the
regulation of Kyoto Protocol, it will be sure to
have brighter prospects to use the fuel cell to
generate electricity in the future.
S.S. Hsieh ppt. 51
53
References

• S.-S. Hsieh, J.-K. Kuo, C.-F. Hwang, and H.-H
  Tasi, A Novel Design
• and Microfabrication for a Micro PEMFC,
  Microsystem Technologies
• ,Vol.10, 2004,pp. 121-126.
• S.-S. Hsieh, C.-F. Huang, J.-K. Kuo, H.-H Tasi,
  and S.-H. Yang, SU-8
• Flow Field Plates for a Micro PEMFC, Journal
  of Solid State
• Electrochemistry, Vol.9,2005,121-131.
• Fabrication and Testing of a Two Cell PEM
  Fuel Cell Stack, Table of
• Contents (2003)
• Dr. Hazem Tawfik, Hydrogen Economy (PEM) Fuel
  Cells
• Life Style Publications
• ( http//www.lifestyle-movement.org.uk/str
  1/publicns.htm )
• Introduction to hydrogen
• ( http//europa.eu.int/comm/research/energ
  y/nn/nn_rt/nn_rt_hy/article_1142_en.htm )
• Energy and Environment

S.S. Hsieh ppt. 52
54

• Thanks for Your Attention !