CIENCE WATCH
The Next Big Thing in Battery Power? They're Working on It
By LEE DYE
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cientists around the world are reporting significant progress in developing a new
generation of lithium batteries that could be the energy source of the future for
everything from laptop computers to electric vehicles.
Although lithium battery technology is only about a decade old, it has already
reached a major fork in the road.
Lithium batteries have four times the energy of lead-acid batteries like those used in cars,
and two to three times the energy density of nickel-cadmium batteries. But rechargeable lithium
batteries that are used in portable electronics have spawned a host of concerns. The metallic
lithium used today produces a byproduct that can burst into flame if exposed to air, and there
have been reports of fires caused by leaking batteries.
That has led several research organizations, including Sandia National Laboratories in
Albuquerque, to explore an entirely different approach.
The goal is to produce a nonmetallic lithium ion battery that eliminates the threat of fire but
still can be recharged quickly, and without loss of output, hundreds of times.
One company, Ultralife Batteries(), which was established in 1991 to acquire the
assets of Eastman Kodak's lithium battery division, is staking its future on the emerging
technology.
"There's a tremendous amount of research worldwide" on lithium ion batteries, especially in
Japan and Western Europe, said Dan Daughty, who manages lithium research at Sandia.
Like any battery, a lithium battery converts chemical energy to electrical energy. It consists
of two electrodes (a cathode and an anode) separated by an electrolyte that produces the
chemical reaction that causes electrons to flow from the cathode to the anode, producing the
current.
Today's lithium batteries use lithium metal anodes, Daughty said, and a liquid electrolyte.
The "battery of the future" uses nonmetallic lithium; thus it is a lithium ion battery.
After many cycles of discharging and recharging, lithium powder builds up in the battery. If
the metal jacket that contains the battery is breached, by puncture or heat, the lithium powder
may be exposed to air and ignite, he said. Failure seems to occur most often during the
recharging cycle, researchers said.
Scientists at Sandia, Ultralife and other institutions are using a nonmetallic lithium ion
trapped in a host material, such as carbon, to build lithium ion batteries. This combination
produces no lithium powder.
Ultralife's new lithium ion batteries use a solid polymer electrolyte, and that offers some
advantages, according to Greg Smith, marketing manager for the firm.
That "revolutionary technology," as he described it, makes it possible to design batteries in
any shape and virtually any size.
"A solid polymer battery can be less than 1 millimeter in thickness," he said. "And you can
do odd shapes, because it is housed in a super-thin, flexible laminate. You can even curve the
cell."
Ultralife claims its batteries can be recharged hundreds of times and don't have the
"memory" that shortens the life span of nickel cadmium batteries.
And the batteries contain no hazardous metals such as lead or mercury, so they can be
discarded safely, Smith said.
Although researchers say lithium ion batteries could be scaled up even for electric vehicles,
the more immediate goal is to make them available for portable electronic devices. But even that
hasn't been easy.
"This is an emerging technology," said Ultralife's Smith.
Sandia's Daughty said the lab has approached several manufactures with the technology, but
has no takers. He blames that partly on the fact that the technology is so new and most
manufacturers already have large investments in production equipment for other types of
batteries.
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Ultralife is not quite ready to begin production-line manufacturing of lithium ion batteries,
although prototypes were sent to more than 60 potential customers, Smith said. The company is
concentrating on consumer electronics, he said, because that offers the best chance of a more
immediate payoff.
Meanwhile, across the Pacific, Japan is moving furiously ahead on lithium battery research.
"The Japanese just dominate the market," Daughty said. Such giants as Sony and Mitsubishi
are leading the charge, at the aggressive urging--and with some financial support--of Japan's
Ministry of International Trade and Industry.
Nonetheless, it may take a while.
"The high-tech world is spoiled by the speed at which electronics advance," said Ultralife's
Smith. Progress in developing and marketing new batteries, he said, "moves about as fast as a
snail."
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Lee Dye can be reached via e-mail at leedye@compuserve.com. |
