From: ethanb@ptolemy.astro.washington.edu (Ethan Bradford)
Newsgroups: sci.energy
Subject: Economist article on car battery and flywheel technology.
Date: 13 Oct 92 19:08:00 GMT
Article-I.D.: ptolemy.ETHANB.92Oct13110800
Organization: U. of Washington

The following article is from The Economist, September 26th, 1992.

The electric car's Achilles' axle

Electric cars can go as fast and far as those with internal combustion
engines at the same cost--so long as batteries are excluded from the
calculation.  Once the batteries are borne in mind, things look much
less promising: the electric cars' speed and range are halved, and their
cost soars.  The trouble is that it is much harder to get electricity
into and out of a battery than it is to pump and burn petrol.  In watts
per kilogram, batteries have a long way to go.

They have been given a good reason to make the journey.  In 1990
California revived the electric-vehicle programmes of a motor industry
that seemed to have lost interest.  The state required that, by 1998, 2%
of all new cars there must emit no air pollution; 10% (more than
200,000) must be emission-free by 2003.  Until other technologies are
developed, emission-free is pronounced "electric".  New York and
Massachusetts have followed California's lead and ten other states are
considering the idea.  After decades of half-hearted work on electric
cars, manufacturers are being presented with a guaranteed market for
them.  If only they had the batteries...

To meet that need, America's Big Three car makers looked (where else?)
to the government.  They drew the Department of Energy (DOE), eager to
promote "competitiveness", into the Unitided States Advanced Battery
Consortium (USABC), along with the Electric Power Research Institute
(EPRI), which represents more than 660 American power companies.  The
consortium will spend $262m, half of it public money, on four-year
battery-improvement programme.  EPRI is also working out how electricity
might be supplied, within ten years, to half a million cars.

The USABC clearly suits the car makers; it suits innovative battery
makers less well.  Battery manufacturers who want its money must agree
to share development costs and to relinquish patent rights to any
innovations they make under contract.  The DOE has largely ignored cries
that this stipulation both flouts a federal law requiring the government
to favour small companies over giants in such matters and discourages
innovators from working with the consortium.

Another controversial decision limits the consortium's research to
medium- and long-term work on chemical-battery technologies.  It has
declared short-term research on advanced lead-acid batteries and
longer-term research on mechanical power storage out of bounds, at least
for the time being.  Meanwhile promising new technologies are emerging
outside the narrow bounds of the USABC--with some fo the work paid for
by the consortium's members.

Ford has invested heavily in a programme to develop molten sodium-sulfur
(NaS) batteries in the hope--some say dream--that it can solve in the
next few years the problems which stumped 30 years, and more than
$700m-worth, of previous research.  BMW and Volkswagen have put their
money into NaS as well.  The batteries can produce a great deal of
power.  The snag is that they freeze solid below 300\deg C (600\deg F). 
They thus require clever insulation and complicated engineering; and
since they drain their own power to keep warm even when parked, they
need to be plugged in frequently.  In short, they are expensive and
inconvenient.

An alternative is to improve the familiar lead-acid battery. 
Electrosource of Austin, Texas, has a design which it says could
produce twice the capacity, twice the life and a quarter of the
recharge time for less cost.  Electrosource uses woven screens of lead
wire, rather than solid plates, for its electrodes.  That increases
botgh the battery's energy capacity and the time it takes to burn out. 
It also allows closer stacking of cells, for more power.  With $14m of
EPRI money, Electrosource plans to build a pilot plant within two
years.

Chrysler plans to use this new battery in its TEVan, an electric
version of its popular Voyager mini-van.  However, the Impact, GM's
two-seater electric sports car, will rely on 32 souped-up conventional
car batteries, since that allows GM to work with its present battery-
production facilities.  Electrosource thinks that the cost of retooling
to make the new type of battery scared GM away.

In Japan, another tried and tested technology is arousing new interest:
the nickel-cadmium (NiCad) rechargeable battery, as used in household
electronics and toys.  Nissan and other Japanese car makers are
attracted by its quick recharge time, long life, and large capacity. 
The cost and environmental dangers of cadmium, however, make the
technology unlikely to win friends in America.  The only medium-term
contract USABC has yet awarded has gone to the newer technology of
nickel metal hydride (NiH): $18.5m to Ovonic Battery of Troy, Michigan,
to make larger versions of the NiH batteries currently used in laptop
computers and cellular phones.  NiH bastteries could give an electric
car twice the range of one powered by conventional lead-acid batteries,
but at considerable cost.

{\bf Taking it for a spin}

All chemical batteries that might be mass-produced in the next decade
seem likely to suffer from limited range, feeble acceleration, expensive
replacement every three to five years and difficulties over recycling
and disposal.  Lithium-polymer batteries, which are being worked on
within the USABC and DOE's Lawrence Livermore National Laboratory, and
also by other groups around the world, might possibly overcome all this
and match the performance offered by gasoline--but commercial production
is unlikely to begin within the next ten years.  However, an entirely
different technology is coming along, outside USABC's self-imposed
remit.  It might well work better than the batters currently under
investigation.

A battery stores energy as chemical potential, but there are other
options.  One of them is the flywheel.  An American coalition of
government, industry and academia started looiking at the use of
flywheels as energy stores in 1975.  Seven years and $90m later, after
energy had retreated from the government's agenda, the programme was
cancelled.  But its spirit lived on.

Richard Post held together some of the group that had been studying the
idea at Lawrence Livermore.  US Flywheel Systems (USFS) of Laguna Hills,
California, has put low-energy flywheels on to satellites, to act as
batteries and stabilising gyroscopes.  The firm now claims to have
designed a high-energy version.  Jack Bitterly, formerly a NASA
engineer, carried out a computer simulation of a similar design for the
army in 1990.  The simulation was so successful that he founded American
Flywheel Systems (AFS) to raise money for a prototype.

Flywheels have a drawback.  The energy in a spinning object depends on
its mass, shape and speed.  A system for use in cars needs to be light
and compact; to store a lot of energy it therefore nees to spin
extremely fast (hundreds of thousands of times a minute).  A solid disc,
even of the strongest material, splits into flying shrapnel at such
speeds; a rim held to an axle by spikes tends to separate from them.

New materials and clever design may be able to get round this.  The
flywheel battery design by AFS has a rim made of strong fibre (such as
kevlar), wound round and round and embedded in epoxy resin.  It is
connected by doughnut-shaped spokes to an expanding hub.  As the wheel
spins faster, the hub gets larger, making the spokes grip tighter.  An
alternating current passed through electromagnetic bearings spins the
wheel up.  To slow it down and bleed off power, simply reverse the
current.  This can be done so quickly that it is possible to draw off
many kilowatts of power.  Friction is minimised by using magnetic and
liquid bearings and by keeping the whole caboodle in a vacuum.  In each
battery, two flywheels spin in opposite directions to counteract
gyroscopic forces.

The AFS design could work at speeds of 200,000rpm or more; stronger
fibres and better bearings could make it even faster.  A simple version
23cm (nine inches) across, made of off-the-shelf materials, could store
at least as much energy per pound as lithium-polymer batteries.  A set
of them could give the cars of the future more range than today's. 
Acceleration and top speed are limited only by the capacity of the
car's circuits, recharge time by the strength of the power source
(eight hours on house current, perhaps 15 minutes at an electric
"service station").  The lifespan is estimated at more than 320,000km
(200,000 miles).  And accidents are not too terrible; though the rim is
moving at 8,650kph, if it fails it merely produces hot fluff, which the
housing can contain.

Power companies are looking at AFS's flywheels as a way to store
off-peak electricity.  Texas Instruments is investigating how they might
be used to store energy from solar cells.  France's Aerospatiale uses
USFS flywheels in satellites.  Both flywheel companies would love to see
their machines in electric cars.  Car makers, however, have decided to
wait.

They are worried not about performance but about price.  The compaines
need cheap and reliable manufacturing processes--something many in the
industry, including observers at EPRI, think will be difficult, and
perhaps impossible, to come up with.  Both AFS and USFS hope to silence
the sceptics.  AFS reckons it needs $10m to produce a prototype by 1994.
Though it has had many suitors--since June 200 individual investors, 60
investment firms, a dozen venture capitalists, and most of the big
brokerage houses have called--it has decided not to go public until it
has developed a commercial product.  Instead, it plans to raise capital
by selling licence options--promises to offer patent licences at a
discount to those who invest now.  AFS and USFS are both negotiating
partnerships with larger companies for work on prototype car abtteries. 
Ed Furia, AFS's president, reckons that once production begins,
econonmies of scale will quickly lower the cost to $5,500 for a
car's-worth of battery.  That would be competitive with chemical
batteries.

If he is right, flywheels, rather than batteries, may profit from the
laws that aim to reduce emissions.  And by the time batteries are able
to deliver similar performance a decade or more from now, they may well
find that the competition has warmed up in other ways.  Hydrogen-powered
buses can be found in Hamburg; some in Washington, DC, work on
Electricity produced by fuel cells.  And low-emission fuels such as
compressed natural gas and liquid propane have a head start over
electricity in being already widely produced and sold.  Unless its
batteries arrive soon, the battery driven car may lose its current
advantages.
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