S. Korean engineers find way to make safe lithium battery

SEOUL, Nov. 17 (Yonhap) -- South Korean engineers have developed a new technology
for making safe rechargeable lithium batteries used in cell phones, laptop
computers and electricity-driven cars, a state-run laboratory said Tuesday.
The Korea Atomic Energy Research Institute (KAERI) said its engineers have come
up with the technology for a new "separator" that is resistant to external heat
and impact. High temperatures and weakness to impact have been cited for causing
fires and explosions in battery cells in the past.
A conventional rechargeable battery separator is made of porous polyethylene that
ordinarily facilitates the flow of lithium ions generated by the positive side of
a battery to the negative side which creates electric power. It can also act as
an electric insulator if there is a problem in the battery cell.
KAERI said the new separator, made by mixing polyethylene, nano-alumina and
flourine-based resin and subjecting this compound to radiation, has effectively
overcome weaknesses of existing batteries.
"Tests showed that the new separator maintains its ability to act as an electric
insulator even if subject to heat of 150 degrees Celsius and considerable outside
impact," a press release by the laboratory said.
It added that normal polyethylene separators on the whole lost their ability to
act as insulators if subject to such conditions.
The laboratory said it has applied for two separate intellectual property rights
patents for the new discovery.
South Korea uses 30 percent of all lithium batteries made in the world, with its
domestic market expected to top 350 billion won (US$303 million) in 2010. The
global market could reach 1 trillion won next year.
yonngong@yna.co.kr
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