With so much media attention showered on nickel-metal
hydride and lithium-ion batteries that power the electric
motors in hybrid vehicles, it's easy to forget that lead-acid
batteries are omnipresent in the hybrid fleet.
Lead-acid battery makers say their product will continue to
play an important role in the auto industry, but that's not
stopping them from researching and developing new chemistries
to meet the power needs of future vehicles.
"In the lithium- and nickel-powered cars there is a small
lead-acid battery that's used for starting those cars. The
(Toyota) Prius has a lead-acid battery in it-they all do," said
Tom Granville, chief executive officer of Axion Power
International Inc., a New Castle, Pa.-based battery maker.
"Even the (Chevy) Volt has a lead-acid battery in it,"
Daniel R. Langdon, president of privately held battery maker
East Penn Manufacturing Co. Inc., said. The Lyon Station,
Pa.-based company manufactures the Deka battery brand.
Indeed, while new battery formulations like lithium-ion and
nickel-metal hydride have stolen the limelight from the humble
lead-acid battery, its role in new vehicles has remained fairly
constant. A mild hybrid, like Toyota Motor Corp.'s popular
Prius sedan, combines a smaller combustion engine with an
electric one that is powered by a nickel-metal hydride
But as Granville pointed out, the Prius still relies on a
12-volt lead-acid battery to spark that combustion engine to
life. The same battery powers the Prius' electrical systems,
like air conditioning, power windows, radio and windshield
wipers. Since car interiors have certain standard design
features, like wiring and voltage requirements, it makes sense
to include a smaller lead-acid battery to run those
So while the high-technology batteries grab all the
attention, the Prius' lead-acid battery serves the same
functions it would in a standard combustion engine vehicle,
albeit as a slightly smaller version.
The main reason for retaining the lead-acid battery in the
system is its reliability.
"I don't see today that there will be a technology to take
the place of a lead-acid battery for starting purposes. If you
have a combustion engine, you will still have a lead-acid
battery as part of the setup," according to Alex Molinaroli,
president of Johnson Controls Inc.'s Power Solutions Group.
"It's in every hybrid car," Granville said. "It's required
in order to meet cold-temperature performance and to meet the
airport test-restarting a car that's been sitting there for 30
to 35 days."
Meanwhile, newer formulations like lithium have earned an
unenviable reputation for being unstable and, at times,
dangerous. Who could forget the exploding Sony Corp. laptop
batteries recalled in 2006, or General Motors Co.'s troubled
2007 Saturn Vue Green Line, whose battery pack experienced
sudden voltage drops? The automaker instituted a voluntary
recall and replaced 9,000 battery packs in 2008 to address the
In contrast, lead-acid is a proven, century-old technology
that continues to foster innovation. One form of advanced
lead-acid battery has even found a role in micro-hybrid
applications. Micro refers to the degree of hybrid technology
in the car rather than the vehicle size, and most micro-hybrids
are simply conventional cars fitted with stop-start technology
that turns off the engine each time the vehicle comes to a
While the technology seems simple, the demands it places on
the lead-acid battery aren't. The battery must power the
cabin's electrical systems and seamlessly restart the engine
each time a driver takes their foot off the brake.
"The technology cuts carbon dioxide emissions by around 15
percent, and it saves fuel in a like amount so it increases
your miles per gallon by about 15 percent. If you add mild
regenerative braking into this equation, you can get it up by
about 25 percent, and the cost of doing this is just a few
hundred dollars as opposed to a nickel-metal hydride or a
lithium battery, which would cost a few thousand," Granville
European original equipment manufacturers (OEMs) began
introducing stop-start technologies in their fleets to meet the
tighter emission standards due to come into force in 2013, but
they ran into trouble while working with traditional lead-acid
batteries. After 4,000 to 6,000 cycles-roughly four to six
months in a hybrid stop-start operation-the charge would drop
to about 20 amps from 80 amps and refuse to recharge.
Axion developed a solution to the problem, which resulted
from a buildup of sulfide on the negative electrode. By
replacing the negative lead electrode with a carbon one,
Axion's batteries avoid the sulfide buildup that renders
traditional batteries inefficient. "The product cycles longer
and more efficiently, and that's a very important part of the
hybrid market," Granville said. "Everyone thought that
lead-acid would be frozen out of these markets, and now there's
apparent potential to use advanced lead-acid to do the
Indeed, in the months following the European Commission's
introduction of tighter emission standards, Axion was swamped
with inquiries from Europe's largest OEMs. "We're a small
company in New Castle, Pa., and all of a sudden we had some of
the largest car manufacturers in the world requesting meetings
with us and wanting to get our product into their test
vehicles," Granville said.
Axion got another boost last August when its partnership
with Exide Technologies, one of the largest international
battery producers, received a $34.3-million grant from the U.S.
Energy Department to develop lead-carbon technology for
micro-hybrid applications under the American Recovery and
"It's what I call the circle of green-building the economy,
producing jobs in this green economy, reducing foreign oil
dependence so that the dollar stays here in this country,
better air quality, recycling. It's the whole shooting match,
really," Granville said.
While Axion focuses on lead-carbon, East Penn Manufacturing
is hedging its bets by pursuing research on a variety of
battery chemistries as the company develops products for
vehicles of the future.
"I think you need to be hedging, looking where it's going,"
Langdon said. "We have to be flexible enough in our new product
development so that we can meet the demands of the consumer in
the future, whether that's lead-acid, carbon lead, lithium or
"We have to be in all those technologies in the next 10
years to make sure we have a viable product line," he added.
"There very well may be a place for both. We're not looking at
it as just being in the lead-acid business. We know how to
manufacture, we know how to handle materials. All of us in this
business are looking at where the future technology is going to
go and we're getting in line for where those opportunities can
take us, whether its lead-acid or not."
East Penn Manufacturing is pursuing some lead-carbon
projects, but declined to comment on the technology due to
non-disclosure agreements. The company also is working on the
development of advanced lead-acid batteries, and last August
received a $32.5-million grant from the Energy Department to
expand production capabilities of these batteries in the United
Langdon readily acknowledges that the company is seeking
opportunities outside the lead-acid battery arena. "If we saw
we had an opportunity in lithium, certainly we'd pursue it.
We're certainly not turning a blind eye. That could be one of
the products we make in the future," he said.
Molinaroli holds a similar view, noting that Johnson
Controls' Power Solutions Group-with sales of nearly $4 billion
in fiscal 2009-was the company's most profitable business. It
has been working on both flooded lead-acid batteries and
advanced absorbent glass mat (AGM) batteries in Europe. This
includes an enhanced flooded lead-acid battery with carbon
additives, while its partnership with French battery maker Saft
SA manufactures lithium batteries used by Daimler AG in its
"We have lots of activity with other chemistries, including
lithium, but we believe it will be more than one chemistry
solution. The lead-acid chemistry will be around and several
other chemistries will come forward," he said.
"I don't know if there's going to be a winner. We need to
know the demands for the applications from OEMs so we can
anticipate how far those chemistries can go, and we haven't yet
been able to get an answer from our customers so we're pursuing