Monday, February 13, 2012
US Senate Outside Witness Testimony On Lithium Ion
Batteries February 2010
Lindsay Leveen (as an individual)
Submitted To the Senate Subcommittee For Energy and Water
Development
OWT on the Subject of plug in vehicles that require
rechargeable lithium batteries.
An Essay on the Thermodynamics and Economics of Lithium
Batteries
My name is Lindsay Leveen. I am a chemical engineer and my
interest is to apply my scientific knowledge to alternate energy sources. My
graduate work involved the study thermodynamics. Over the last 35 years my work
has been in cryogenics, microelectronic device fabrication, nanotechnology
development, fuel cell fabrication, and most recently biotechnology.
Purpose: The purpose of this essay is to provide the
subcommittee with reasoning based on thermodynamics why lithium batteries will
likely not lower in cost and therefore why plug in passenger vehicles will
probably not make any significant dent in the consumption of gasoline and
diesel. I wish to prevent the waste of precious resources on a technology that I
believe is headed toward a dead end.
I have no commercial interest in any energy or battery
technology and am writing this essay as a citizen simply to inform the Senate
Subcommittee on Energy and Water Development of the severe thermodynamic
limitations of Lithium Secondary Batteries and therefore the probable long term
unaffordable economics associated with plug in passenger vehicles (cars and
trucks) that will rely upon these batteries. Much of this report is taken from
my presentations, reports, and publications or from my website
www.greenexplored.com .
Thermodynamics – definition: “the science concerned with
the relations between heat and mechanical energy or work, and the conversion of
one into the other: modern thermodynamics deals with the properties of systems
for the description of which temperature is a necessary coordinate.”
(dictionary.com).
Moore’s Law and Learning Rates for Technologies: Gordon
Moore one of the founders of Intel Corporation, postulated that semiconductor
integrated circuits would enjoy a doubling in performance in a period of every
18 months. This rate of learning allows performance to be improved exponentially
with time for the same original cost.
Many technologies that engineers and scientists develop
need a “Moore’s Law” in order to improve their performance and correspondingly
their economics to capture vast markets. Most efforts around the improvement of
alternate energy technologies vis a vis competing with fossil fuels have not
yielded these “Moore’s Law” rates of learning. In particular for the past decade
as much as six billion dollars has been spent without any real success toward
the “learning curve” of PEM fuel cells. Much of these six billion dollars was
appropriated by the Federal Government. The learning curve for PEM fuel cells
over the past decade yielded a yearly learning rate of less than 2%. By
comparison the Moore’s Law yearly learning rate for integrated circuits has
averaged over 40% for more than three decades.
My experience with Moore’s Law: For almost twenty years I
directed teams of engineers that designed state of the art Integrated Circuit
(IC) fabrication facilities that helped drive this rapid rate of learning and
therefore cost improvement in computers and other electronic devices. A simple
explanation for the high learning rates in IC fabrication is that the technology
was neither constrained by thermodynamics nor reaction kinetics but simply by
the line width of circuits within the ICs. To drive Moore’s law in IC
fabrication improvements in lithography, higher purity gases for deposition,
implantation, and etch, as well as the occasional increase in the size of wafer
being fabricated were needed.
Moore’s Law, Thermodynamics and Lithium Batteries: To drive
the learning rate in PEM fuel cells and similarly lithium secondary batteries
thermodynamic and reaction kinetic constraints have to be overcome. The reason
why thermodynamics places constraints is that the functioning of these systems
depends on chemical reactions. Thermodynamics determines how much useful energy
can be derived from a chemical reaction. But we know that the thermodynamic
constraints cannot be overcome as the laws of thermodynamics cannot be
challenged nor avoided. ICs do not undergo chemical reactions to function, but
all batteries and fuel cells do involve chemical reactions to deliver energy. It
is these chemical reactions that are limiting the possible learning rate.
The Resulting Economic Problem: Significant effort and much
money is now being spent on advanced batteries for plug in full electric or plug
in hybrid vehicles. Such vehicles will require between 10 kilowatt hours and 50
kilowatt hours of stored electricity if the range of the vehicle purely
propelled on stored electricity is to be between 40 and 200 miles. Lithium
chemistry based secondary (chargeable) batteries presently offer the best
performance on a weight and volume basis and are therefore the primary
technology that a “Moore’s law” is now hoped for to solve the world’s addiction
to fossil oil. Present costs of such battery packs at the retail level range
from $800 per kilowatt hour of storage to over $2,000 per kilowatt hour of
storage. One can purchase a 48 volt 20 amp hour Ping Battery for an electric
bicycle directly from this Chinese “manufacturer” for less than $800 delivered
by UPS to any address in the USA. A123 offers a battery system that will modify
a standard Prius to a 5 kilowatt hour plug in Prius for $11,000 or around $2,200
per kilowatt hour fully installed by a service station in San Francisco. The
Ping battery delivers much less instantaneous power (watts) and that is the
reason their batteries are less expensive on a stored energy basis (watt hours)
than are the A 123 batteries. Both the Ping and the A123 batteries claim safety
and claim to be manufactured with phosphate technology that will neither short
circuit nor burn.
Economic Case Study The Example The Standard Prius vs Plug
in Prius: The following is an economic analysis of a standard Prius versus a
plug in Prius using A 123’s lithium battery pack;
The standard Prius will get 50 MPG and let’s assume that
the driver drives 12,000 miles a year. The standard Prius driver will need to
purchase 240 gallons a year of gasoline at an estimated cost of $720 per year
with gasoline at selling for $3 per gallon. If the driver purchased the A 123
plug in system and can recharge the system at home and at work such that half
the mileage driven in a year is on batteries and half is on gasoline the driver
will save $360 a year on gasoline. The driver will need to buy some 2,000
kilowatt hours a year of electricity from the grid in order to save this
gasoline. At 10 cents per kilowatt hour the driver will spend $200 a year for
electric power and will therefore only enjoy $160 a year in net operating
savings. The $11,000 set of batteries have a maximum expected life of 8 years
and the owner must set aside $1,375 a year for battery replacement without
accounting for the time value of money. The battery replacement cost is simply
too expensive to justify the savings in gasoline. How high do gasoline costs
have to rise and how little do batteries have to cost to make the plug in
viable? Let’s assume gas prices reach $6 per gallon and electricity remains at
10 cents a kilowatt hours we have a yearly operating savings of $520. These
savings will still be far short of the money needed for battery replacement.
The A 123 batteries will need to drop to 15% of their
present cost to make the proposition of converting a Prius to a plug in
“worthwhile”. To reach this cost target in a decade one needs a yearly learning
rate of approximately 26%. With 35 years of work experience, I have concluded
that in the best case of battery costs (no inflation in raw materials) a 4 or 5%
yearly learning rate could be achieved over the next decade. But if we believe
that gasoline will double then we also have to assume that plastics, copper,
cobalt, nickel, graphite, etc. will also double in unit cost. As raw materials
account for three quarters of the manufacturing cost of lithium batteries the
inflation adjusted cost will grow at a higher yearly rate than the learning rate
will lower costs. My prognostication is therefore that lithium secondary
batteries will likely cost more per unit of energy stored in 2020 than they do
today.
Toyota is a company well known for its cars with improved
fuel economy and therefore is a master of thermodynamics and must have
“optimized” the cost and performance of its batteries in the standard Prius
deploying a relatively small battery pack and with the choice of Nickel Metal
Hydride chemistry rather than lithium chemistry. While Toyota may be
experiencing safety problems no one can fault this company on fuel efficiency.
Other car companies such as Ford have also chosen Nickel Metal Hydride as their
hybrid car battery platform. Fisker and GM are touting plug in hybrids with
lithium batteries and are much more aggressive in their claims of cost
improvement and their ability to drive “Moore’s Law” in their battery systems.
My educated guess on all of this is that Toyota, Ford and the car manufacturers
that stick with smaller nickel metal hydride battery systems and the traditional
non plug in hybrid will sell tens of millions of such vehicles over the next
decade. Renault, GM, Fisker, Tesla, and others who go for plug in hybrids or
full electric vehicles will only sell a few tens of thousands of vehicles in the
next decade. I simply believe we will not have “Moore’s Law” at play here but
have a very fractional Moore’s Law that holds.
Argonne National Labs published an exhaustive review of the
materials and associated costs of lithium batteries back in May of 2000.
http://www.transportation.anl.gov/pdfs/TA/149.pdf The total material cost for
the cell was estimated at $1.28 and the total manufacturing cost of the cell
including overhead and labor was estimated at $1.70. This Argonne report is
perhaps the best report written on the economics associated with lithium battery
fabrication. Actually had folks read this report back in 2000 they would have
realized that the learning curve for lithium batteries would be painfully slow.
Materials just make up far too much of a fraction of the battery cost and the
quantity of materials is fixed by the chemistry. Therefore economies of scale
could not drive a Moore’s Law type rate of learning and a very fractional
Moore’s Law resulted. In the early years of lithium cell development from
approximately 1990 to 2000, the improvements in chemistry and in economies of
scale did allow the technology to enjoy a Moore’s Law type learning rate and it
has been reported that costs of an 18650 cell reduced from $18 to $2 per cell in
that decade. Unfortunately the technology has now hit an asymptote in their cost
reduction curve.
Just by doing a Google search on an 18650 lithium ion
battery I came across this link http://www.batteryjunction.com/li18322mahre.html
. This site lists a selling price of $5.29 each for 200 or more cells. The cells
are 3.7 volts with 2.2 amp hours so they are capable of holding 8.1 watt hours
of energy from full charge to discharge. Expressed in cost per kilowatt hour of
nominal capacity these loose cells cost around $650. My guess is that if applied
today’s costs of cobalt, nickel, lithium, lithium salts, plastics, copper,
graphite, and other constituent materials that make up a cell, the material cost
in November 2009 compared with May 2000 have increased by more than 150% and a
current estimate of the materials used in the Argonne labs report will show cost
of about $3 per cell versus $1.28 back in May 2000. Hence this company sells the
cells for $5.29 each. From my previous analysis of the probable learning rate I
would not surprised if in 2020 the selling price per 18650 lithium cell is as
high as $6 rather than as low as $3.
Conclusion: Lithium batteries are and will remain best
suited for items as small as a cell phone and as large as a bicycle. The cost
relative to performance or these batteries will likely not improve by much in
the coming decade. Although some standard hybrid vehicles may use lithium
batteries with low capacity, plug in vehicles with larger than 10 mile range of
travel on batteries will likely not proliferate. Given the likely scenario that
plug in passenger cars and trucks based on lithium battery technology will not
reduce US consumption of gasoline and diesel fuel in large measure, I am asking
the subcommittee to limit the funds that the US government will appropriate for
research and development of this technology.
Thank you
Lindsay Leveen