PARK RIDGE, Ill.  Experts said this week that the electric-vehicle debate raging in California may yield both good news and bad.

The good news, they said, is that continued battery development efforts in the automotive arena are likely to trickle down to handheld devices, notebook computers and cell phones.

The bad news is that those developments won't be significant enough to pump up the dismal sales of battery-powered vehicles. “There's no battery technology on the horizon that can help the situation in California,” said Donald Sadoway, a professor of materials science and engineering at Massachusetts Institute of Technology and a nationally recognized battery expert. “Batteries are improving, but the development is evolutionary, not revolutionary.”

Unfortunately for automakers and environmentalists alike, a growing number of studies are showing that batteries need a big boost if so-called “pure electric vehicles” are to be successful. A recent study performed by Argonne National Laboratory for the U.S. Department of Energy stated that lack of driving range and high cost will plague battery-powered cars on dealership lots. “Electric vehicles are just not suitable for the mass market,” said Anant Vyas, a research engineer for Argonne's Center for Transportation Research. “They are niche vehicles only.” A separate Delphi study by the University of Michigan's Office for the Study of Automotive Transportation predicts similarly disappointing results for battery-powered cars.

Still, the United States Advanced Battery Consortium (USABC) recently signed an agreement to enter into the next phase of its electric-vehicle battery efforts, which calls for $60 million in funding for research and development. The organization, which has already pumped $260 million into its programs, needs to continue its efforts in light of the California zero-emission vehicles mandate, which dictates that by 2003, a certain percentage of the vehicles that manufacturers produce and sell in California must be electric.

“We haven't identified any technology that will take us to our long-term goals,” said Lawrence Simmering, chairman of the USABC management committee. “But we intend to keep working at it.”

Never say never

Battery researchers are careful to say that it's not impossible to build a low-cost battery that provides 300 miles of driving range in a full-sized sedan. “In theory, it can be done,” said Ira Bloom, manager of the Electrochemical Analysis and Diagnostics Laboratory at Argonne National Laboratory. “But no one is close right now.”

The problem, experts said, is that battery development is maddeningly complex. Even if engineers create a battery with the energy to provide 300 miles of driving range, they must still meet cost, safety, reliability and durability constraints. That's why a broad array of electric-vehicle battery technologies have already failed in the automotive marketplace. Sodium-sulfur batteries, for example, were the darling of the automotive world in the late '80s, until the brittle ceramic separators contained inside them began cracking and causing fires. Similarly, many engineers favored nickel-iron batteries during the mid '80s, until the cells began short-circuiting after extended use. “Building a battery is a tremendously tricky business,” Bloom said. “There are so many trade-offs to consider. Just when you think you've solved one problem, two more crop up.”

Development engineers say that those problems are doubly hard to solve in automotive applications. Vehicles, they say, place demands on batteries that laptop computers and cellular phones never would. Laptops, for example, operate on miniscule electrical currents and therefore can use batteries that cost about $10,000 per kilowatt-hour (kWh). Similarly, cell phones operate for short durations and use batteries that cost from $1,000 to $5,000 per kWh. Cars, however, must drive for as long as five straight hours, drawing deeply on battery power as they climb hills and accelerate in traffic. Worse, experts say that electric-vehicle batteries must cost no more than $150 per kWh to be successful.

Long-range solutions

For now, battery experts and automotive engineers agree that today's technologies don't yet come close to the $150 per kWh figure. Nickel-metal hydride battery packs, as used in the Ford Ranger EV pickup and GM EV1, cost about $1,000 per kWh. Although environmentalists claim those figures are vastly inflated, the cost of battery packs for those vehicles has been said to approach $40,000.

To squeeze cost out of the existing batteries, battery makers say they must have higher volumes. Higher volumes provide economies of scale for materials and components, and more importantly, enable them to use automated production to build the batteries. Some battery makers say that such measures could cut battery cost to as low as $250 per kWh.

For electric vehicles to be competitive, the USABC also has set a goal of 200 watts per hour per kilogram (W-hr/kg), which roughly translates to about 200 miles of range in a typical sedan. Today, however, no battery comes close to that figure.

Nickel-metal hydride batteries, which work by moving ions between a nickel-metal hydride cathode and a nickel hydroxide anode, generate about 75 W-hr/kg. Argonne's study predicts that nickel-metal hydride's energy density will rise to about 85 W-hr/kg by the year 2020 but will improve little beyond that.

Experts say that lithium batteries are the best bet for reaching higher energy densities. “In the long term, we've narrowed it down to lithium-ion and lithium-polymer batteries,” said USABC's Simmering . “It's not clear which one will be the winner, but it's good to have two competing technologies.”

The advantage of lithium, engineers say, is that it's the lightest-weight metal in the periodic table, and therefore offers the potential for more energy per weight, which is known as energy density.

Lithium ion, which is already used in laptop computer batteries, generates its energy by dissolving lithium ions and transporting them between the anode and cathode. It distinguishes itself, however, through its use of materials: Its anode is made of lithium cobalt dioxide and its cathode, a nongraphitizing carbon. During operation, the lithium ions move through a liquid electrolyte, between the lithium-cobalt electrode and the carbon electrode.

In contrast, lithium-polymer batteries employ a very thin polymer membrane instead of a liquid electrolyte. As a result, the weight of the battery is reduced. Further, the design enables engineers to eliminate cobalt from the cathode, which lowers the cost.

Engineers hope that the thin-film polymer will allow for high-volume production techniques that could drive down the battery's cost. Until recently, 3M Corp. had planned to mass-produce the thin-film polymer using techniques similar to those employed on Scotch Magic Tape and Post-It Notes. The manufacturing giant recently pulled out of the lithium-polymer effort, however, casting doubt on the immediate future of the technology.

Trickle down

Similar efforts are in progress at Massachusetts Institute of Technology (MIT), where researchers have developed a competing lithium-polymer battery that could ultimately achieve energy densities of 300 W-hr/kg, according to its developers. The technology, which uses a multiple-layer configuration of polymer and metal resembling a potato chip bag, is funded by the Office of Naval Research and is said to be 5 to 10 years from commercialization. “There are still tons of questions that have to be answered before anyone tries to do volume production of this,” MIT's Sadoway said. “But we've demonstrated high energies in ambient and subambient temperatures.”

The flexible polymer layer, Sadoway said, could ultimately enable engineers to create batteries that could be molded to fit within a vehicle's body panels. The design could also be constructed as thin as a quarter-inch, enabling a small battery to be placed on the back of a credit card. As a result, it could be used in cell phones, laptop computers and other electronic products. “The first applications will be in handhelds,” Sadoway predicted. “This battery could be used for virtually any application.”

Engineers say the same logic applies for other battery types, including lithium-ion, nickel-metal hydride and advanced lead-acid, among others. “Just as the U.S. space program drove technology, we will move the technology needle forward,” said Simmering of USABC. “And the results will be used in all kinds of applications.”

Simmering and other experts, however, emphasized that lithium batteries and other promising technologies are far from serving as a solution to the dilemma in California. Manufacturing questions for such technologies abound. And costs, in many cases, are still astronomical. What's more, Argonne National Laboratory has conservatively predicted that even the best lithium batteries will not exceed 170 W-hr/kg by the year 2020.

“People are not going to flock to battery-powered vehicles unless they offer 250 miles to a charge,” Sadoway said. “Unfortunately, that's not going to happen in the near future, even with the best lithium-ion technology.”

For that reason, most experts expect automakers to balk at building full-sized, battery-powered cars. That's why Ford Motor Co. has announced it will meet the California mandate by building golf cart-like vehicles, and DaimlerChrysler is expected to take the same approach. “If the auto companies could make a big electric car now, they'd do it,” Sadoway said. “But right now, it's just not realistic.”