MSE 156 - Solar Cells, Fuel Cells and Batteries:
Materials for the Energy Solution
Course Information
Instructor: Professor Bruce Clemens
356 McCullough Building
650 725 7455
bmc@stanford.edu
Course Assistant: Vardaan Chawla
210 McCullough Building
650 723 6778
chawla@stanford.edu
Location and Time: 11:00-12:15, Tuesday, Thursday
Room 120, Building 60
Grading: Homework
Labs
Project
Midterm
25%
20%
20%
35%
Safety Training:
Course Assignments: Homework – four problem sets
Labs – two labs with write-up
Project - device construction
Exams - In-class midterm
Required!
Procedure TBA
MSE 156 - Solar Cells, Fuel Cells and Batteries:
Materials for the Energy Solution
Course Outline
The energy problem: causes, scope and scale
Energy usage
Global warming
Peak oil
Assessing energy resources
Solar Cells
Solar spectrum
Basic semiconductor physics
Electron and hole energy bands
p-n junctions
Photovoltaic effect
Solar cell operation and characteristics
Fill factor
Efficiency
Batteries
Basic electrochemistry
Thermodynamic concepts
Cell potentials
Cell reactions and half reactions
Hydrogen reference electrode
Reaction kinetics
Battery technologies
Basic battery construction
Lead-acid
Alkaline
Ni-metal hydride
Li ion
Li polymer
Battery lifetime and operation issues
Charging and re-charging cycle
Temperature effects
Degradation
Fuel Cells
Basic fuel cell operation
Fuel cell reactions: thermodynamics and kinetics
Differences from batteries
Materials issues in solar cells
Advantages and issues in fuel cells
Emerging solar cell technology
Types of fuel cells
Proton exchange membrane (polymer electrolyte membrane)
Solid oxide
Photovoltaic systems
Grid tied versus battery backup
Emerging technologies and materials issues
Resources
Energy and Global Warming
Richard Heinberg “The Party’s Over: Oil, War and the Fate of Industrial Societies”
David Goodstein “The End of the Age of Oil”
Jared Diamond “Collapse: How Societies Choose to Fail or Succeed”
Mark Bowen “Thin Ice: Unlocking the Secrets of Climate in the World’s Highest Mountains”
Basil Gelpke, Ray McCormack “A Crude Awakening: The Oil Crash”
Al Gore “An Inconvenient Truth”
Fred Krupp and Miriam Horn “Earth: The Sequel”
Godfrey Boyle “Renewable Energy”
Solar Cells
Jenny Nelson “The Physics of Solar Cells”
Antonio Luque and Steven Hegedus “Handbook of Photovoltaic Science and Engineering
Thomas Markvart “Solar Electricity (Second Edition)”
Batteries
David Linden, Thomas B. Reddy “The Handbook of Batteries”
(available online at http://www.knovel.com/knovel2/Toc.jsp?BookID=627)
Almost any chemistry text, e.g. Gordon Brown “Physical Chemistry”
Fuel Cells
Ryan O’Hayre, Suk-Won Cha, Whitney Colella, Fritz B. Prinz “Fuel Cell
Fundamentals”
Energy
Definition:
The property of matter and radiation that is manifest as a capacity to perform work (Apple Dictionary)
Several different forms, such as kinetic, potential, thermal, electromagnetic, chemical, nuclear, and
mass have been defined to explain all known natural phenomena (Wikipedia)
The strength and vitality required for sustained physical or mental activity (Apple Dictionary)
force
Units and Conversions:
distance
Si Unit of energy is Joule (J)
Mechanical work increases energy
of a body (kinetic or potential)
1 Joule is:
•
•
•
•
Power
time
the energy required to lift a small apple (102 g) one meter against Earth's gravity.
the amount of energy, as heat, that a quiet person produces every hundredth of a second.
the energy required to heat one gram of dry, cool air by 1 degree Celsius.
one hundredth of the energy a person can get by drinking a single 5 mm diameter droplet of
beer.
1 electron Volt = 1.602 x 10-19 J
Forms of Energy
Kinetic energy – the energy possessed by a moving mass
Kinetic energy = (mass x speed2)/2
Kinetic energy within a body determines its temperature
- matter consists of atoms or molecules
- atoms or molecules in have kinetic energy manifested as vibration or motion
- the higher the temperature the faster the atoms or molecules are moving
- this atomic scale kinetic energy is known as thermal energy
Potential or gravitational energy
Potential energy = mass x acceleration due to gravity x height
Force
Distance
At the atomic scale gravitational force is insignificant and electrical force (forces
between charges) dominates
- Electrical energy is the energy associated with electrical forces
- At the atomistic scale this electrical energy is chemical energy (the energy
associated with chemical bonds)
Forms of Energy
Macroscopically (and technologically) electrical energy is
manifested as electrical currents driving loads. For example
a current of one amp through a load of one ohm resistance
operating for one second is our old friend a Joule.
Electrical energy is also associated with fields (electrical
and magnetic)
Light is a form of electromagnetic energy
• Nuclear energy is the energy associated with the
forces between the particles in the atoms nucleus
• At the sub-atomic length scales of the nucleus, these
forces are much stronger than electrical forces
• Nuclear reactions convert mass to energy
E = mc2
Energy Conversion
The first law of thermodynamics says that in all processes, energy is conserved; neither created or
destroyed (must include mass energy if considering nuclear processes).
However, the second law of thermodynamics says that in converting from one form of energy to
another, the useful output is always less than the input
The efficiency is the ratio of useful output to required input
Typical efficiencies
Water turbine
90 %
Electrical Motor
90 %
Coal fired power station
35 – 40 %
Internal combustion engine 10 – 20 %
Solar cells
10 – 40 %
Energy Content
1 metric ton (tonne) oil = 1000 kg = 7.33 barrels = 307.9 gallons
Burning 1 metric ton oil releases
42 x 109 J or 12 MWh
This is the energy content of a tonne of oil
Energy Unit toe (tonne oil equivalent)
1 toe is the energy content of a tonne of oil
1 toe = 42 GJ
1 Mtoe = 42 x 1015 J = 42 PJ
Efficiency of Use - Electrical Energy Conversion Example
With a conversion efficiency of 37.5 %, one
metric ton produces 15.75 GJ or 4.5 MWh of
electrical energy
When comparing energy forms it is important to
compare apples to apples. A power plant needs
about 2.7 tonnes of oil to produce 1 toe of electrical
energy.
World Energy Consumption
BP Statistical Review of World Energy June 2007
Distribution of Energy Consumption
The world at night
http://www.skyscrapercity.com/showthread.php?t=326298
Distribution of Energy Consumption
BP Statistical Review of World Energy June 2007
Are We Running Out of Oil?
As we near peak:
•
Exponential growth of
energy usage will slow
•
Demand will outstrip
supply
•
Price will rapidly
escalate (no elasticity in
demand - we are addicted to
energy!)
Other Energy Reservoirs
Are We Cooking the Earth?
Shepard Glacier, Glacier
National Park, Montana
1913
“Climate change and trace gases”, James Hanse, Makiki Sato, Pusker
Kharecha, Gary Russell, David W. Lea and Mark Siddall. Philosophical
Transactions of the Royal Society A, 365, 1925-54, (2007).
3 kg of CO2 released
for each kg oil burned
2005
http://www.livescience.com
/environment/060324_glacier_melt.html
http://www.worldviewofglobalwarming.org/
Electromagnetic Radiation
Speed of light
E
H
Permittivity
Frequency:
Permeability
of free space
Wavelength
z
Quantized energy: