Laptops may get more battery life from silver-zinc

by Agam Shah

May 1, 2008 —

Laptop users may soon get longer battery life from their machines, with ZPower
set to plug in its new silver-zinc batteries, which it claims last significantly
longer than traditional lithium-ion batteries.

The batteries will be available in consumer and business laptops from major
PC makers starting in August, according to Ross Dueber, the CEO of ZPower, although
he declined to name any of the vendors on Thursday.

Silver-zinc batteries pack more energy than lithium-ion batteries, giving laptops
40 percent more run time, according to Dueber. If a laptop runs for two hours
with a lithium-ion battery, it should run for closer to three hours with a silver-zinc
battery, he said.

The battery's water-based chemistry also makes it nonflammable, compared to
lithium-ion, which uses dimethyl carbonate, a flammable liquid. Cells can go
off "like firecrackers" in lithium-ion batteries, Dueber said.

The silver-zinc batteries also won't degrade in capacity during the first year,
while lithium-ion batteries can lose up to 30 percent of their capacity over
that period, Dueber said. After a year, however, silver-zinc batteries start
degrading at a rate similar to lithium-ion batteries.

Silver-zinc is not a new technology, said Vishal Sapru, industry manager of
power systems group at Frost & Sullivan. Early batteries were mainly for
one-time use in military and aerospace devices, and ZPower is adding recharge
capabilities to those batteries, Sapru said.

The batteries could be good for consumers who want an alternative to lithium-ion
batteries, which have received "unfortunate" publicity lately for
catching fire, said Jeff Shepard, president of the Darnell Group.

"What we see here is a very strong product that will alleviate those issues.
I don't know if it's going to be a silver bullet, but it could be a viable alternative,"
Shepard said. Because the technology is relatively new, any imperfections might
not be known yet, so PC makers will take a wait-and-see approach, he predicted.

Sapru said he thinks the concerns about lithium iron batteries are overblown.
"Think of how many laptops and cell phones we use and carry," he said.
Companies like Valence Technologies and A123 Systems are researching phosphate
material that should further reduce the fire risk.

It also remains to be seen if silver-zinc batteries can compete on price, since
lithium-ion is relatively cheap, Sapru said. The silver-zinc batteries contain
silver, which can be expensive.

ZPower is starting off with laptops, but it plans batteries for mobile devices
like cell phones in a few years, Dueber said. The company needs to get the technology
validated to encourage other vendors to adopt it.

The focus on mobile products comes partly from Intel Capital, which invested
in the company in 2004, Dueber said.

IDG News Service