The New York Times (NYTF) Automobiles; Section F AUTOS ON
FRIDAY/TECHNOLOGY High-Voltage Benefits Of Improved Batteries By
MATTHEW L. WALD 03/26/99 c. 1999 New York Times Company
ONE of the most primitive and troublesome components under a car's
hood, the battery, is due for an update, auto company executives say.
As a result, there could be a cascade of new technologies that would
make cars more fuel-efficient and less likely to turn up dead on cold
winter mornings.
For as long as cars have had batteries, they have stored electricity
with a chemical reaction involving lead and acid. Although 6-volt
systems were once common, automotive electrical systems were
standardized at 12 volts in 1955. Thus, the design now in use has
outlived such mainstays as carburetors, bias-ply tires and leaded
gasoline.
Engineers want to redesign the electrical system partly because they
would like to run more parts of a standard car on electricity, even if
the basic energy source is still a gasoline-driven engine. Two
candidates for conversion to electricity are power steering units and
some components of transmissions. Both now typically operate on
hydraulic power, which in turn is produced by a pump driven by belts
that run off the driveshaft. Electric pumps can produce hydraulic
pressure more efficiently in applications where the need for pressure
is sporadic. And in some applications, engineers think they can
dispense with hydraulics altogether and do the job with electricity.
But 12-volt motors that pump hydraulic fluid or move mechanical
components like steering systems are relatively big and inefficient.
Further, the cables that move electricity around at 12 volts are thick
and heavy, and the heavier the cable the more energy is lost within
the cable itself. With higher voltage, engineers could use thinner
cables, saving weight and energy.
At 12 volts, ''we end up adding so many pounds of wire,'' said Robert
C. Stempel, an advocate of the change. Mr. Stempel, the former
chairman of the General Motors Corporation, is now chairman of Energy
Conversion Devices Inc. of Troy, Mich., which pioneered nickel
metal-hydride batteries, the kind used in cellular phones and laptop
computers. ''Isn't it time to raise voltage?'' he asked.
The standard car battery is known in the industry as an S.L.I.
battery, for starting, lighting and ignition. By adding cells,
lead-acid S.L.I.'s could be made to run at any voltage. But these
batteries are bulky already and would quickly become more so as their
voltage was increased. Mr. Stempel hopes to sell nickel metal-hydride
batteries with more than one pair of terminals, each pair giving off a
different voltage -- for example, 12 volts out of one pair, to run the
radio, and 42 out of the other pair, for the power steering.
There are other reasons, experts at auto manufacturers say, to move
into more modern S.L.I. batteries, like the ones that have marched
through a range of other consumer products like portable tape players,
cellular phones and laptop computers. Nickel metal-hydride is a
leading contender, but the answer might be lithium ion, which is also
in commercial use in portable electronic devices. Or it could be some
battery technologies that do not yet exist in other products.
Laptop and phone batteries store more energy per pound and withstand
deep discharges better; in contrast, the standard automotive lead-acid
battery is irreparably damaged by just a few full discharges -- as
when the driver leaves the lights on. And at extremely low
temperatures, nickel metal-hydride loses less of its ability to
deliver current than lead-acid does, its backers say. That is a
consumer benefit that potential purchasers would have to be convinced
was worth the extra cost. But auto makers might be more likely to
change the electrical system for a more direct reason, better fuel
economy, particularly in Japan and Europe.
Mark W. Verbrugge, a General Motors technology specialist now on loan
to the United States Advanced Battery Consortium, a research group
financed by the Federal Government and the auto companies, said that
continuously variable transmissions -- which are under development by
many leading car companies and offered in the United States on the
Honda Civic HX -- would be good candidates for controls operated by an
electric or electro-hydraulic source. This type of transmission does
not use conventional gears, but belts and pulleys, which could be
manipulated by electric-powered controls, he said.
Steering systems are also a candidate for change. Auto designers would
have new flexibility if the power steering did not have to be
connected to the driveshaft by a belt, he said. Mr. Verbrugge said
that these innovations might turn up first in Japanese models, where
fuel economy was more important.
Lead-acid has a significant advantage, though: its cost. The business
is so competitive that profits are measured in pennies per battery,
industry executives say. In a new car, the lead-acid battery costs the
auto company only about $25, said John R. Wallace, director of
environmental vehicles at Ford. A nickel metal-hydride battery would
cost more than $100 extra, he said, and at that price it would be hard
to justify.
Battery storage capacity is often measured in kilowatt-hours. One
kilowatt-hour is the amount of electricity needed to keep ten 100-watt
bulbs lit for an hour; it sells at retail for about 8 cents.
''Your laptop battery costs thousands of dollars per kilowatt-hour of
capacity,'' Mr. Wallace said. ''An electric vehicle battery of today
costs maybe $1,000 a kilowatt-hour. Your S.L.I. battery costs 50
bucks.''
Mr. Stempel, though, predicted that prices would fall with mass
production. And if auto makers choose S.L.I. batteries using nickel
metal-hydride for even a small part of their production, he said, the
demand would drive output high enough to allow automation and other
cost-cutting technologies. That, he said, could make a beefed-up
battery in a gasoline car a stepping stone to a purely electric car
that would be more affordable than those now on the market.
...
|
