The single most critical issue for plug in vehicles is the batteries. First generation plug in vehicles had 12 to 15 car batteries to operate. Operation with fewer batteries with stronger charges that have a longer range of operation between recharges. This is a good example of the new nanotechnology, and it promises to be a major breakthrough. M


An Electrifying Startup
A new lithium-ion battery from A123 Systems could help electric cars and hybrids come to dominate the roads.

By Kevin Bullis

Go to this link to read entire article and to view video (free membership required)

Technology Review: An Electrifying Startup

It is the quickest electric motorcycle in the world. On a popular YouTube video, the black dragster cycle nearly disappears in a cloud of smoke as the driver does a "burn-out," spinning the back wheel to heat it up. As the smoke drifts away, the driver settles into position and hits a switch, and the bike surges forward, accelerating to 60 miles per hour in less than a second. Seven seconds later it crosses the quarter-mile mark at 168 miles per hour--quick enough to compete with gas-powered dragsters.

What powers the "Killacycle" is a novel lithium-ion battery developed by A123 Systems, a startup in Watertown, MA--one of a handful of companies working on similar technology. The company's batteries store more than twice as much energy as nickel-metal hydride batteries, the type used in today's hybrid cars, while delivering the bursts of power necessary for high performance. A radically modified version of the lithium-ion batteries used in portable electronics, the technology could jump-start the long-sputtering electric-vehicle market, which today represents a tiny fraction of 1 percent of vehicle sales in the United States. A123's batteries in particular have attracted the interest of General Motors, which is testing them as a way to power the Volt, an electric car with a gasoline generator; the vehicle is expected to go into mass production as early as 2010.

In the past, automakers have blamed electric vehicles' poor sales on their lead-acid or nickel-metal hydride batteries, which were so heavy that they limited the vehicles' range and so bulky that they took up trunk space. While conventional lithium-ion batteries are much lighter and more compact, they're not cost effective for electric vehicles. That's partly because they use lithium cobalt oxide electrodes, which can be unstable: batteries based on them wear out after a couple of years and can burst into flame if punctured, crushed, overcharged, or overheated. Some auto*makers have tried to engineer their way around these problems, but the results have been expensive.

A123's batteries could finally make lithium-ion technology practical for the auto industry. Instead of cobalt oxide, they use an electrode material made from nanoparticles of lithium iron phosphate modified with trace metals. The resulting batteries are unlikely to catch fire, even if crushed in an accident. They are also much hardier than conventional lithium-ion batteries: A123 predicts that they will last longer than the typical lifetime of a car.

The A123 batteries for GM's Volt store enough energy for 40 miles of driving, enough to cover daily commutes. (On longer trips, the small gasoline engine would kick in to recharge the battery, extending the range to more than 400 miles.) GM plans to sell the vehicles for around $30,000 to $35,000; the company thinks it can sell hundreds of thousands at that price in the first several years, and J. D. Power and Associates estimates that GM will sell nearly 300,000 by 2014.

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Any news on the power to weight of these batteries? (kWh/kg)

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Set your destination with your heart, get there with your mind.

"The wisest men follow their own direction." - Euripides

And there is more to nanotech and plug in electric vehicles. M

Friday, January 04, 2008

Super-Charging Lithium Batteries
Nanowire electrodes could improve the performance of electric vehicles.

By Peter Fairley

Existing lithium batteries can enable battery-powered electrical vehicles to travel hundreds of miles on a charge, prompting a race among major automakers to demonstrate that the batteries are safe and durable enough for mass marketing. Battery developers, meanwhile, continue to push lithium performance. Last month, Stanford University materials scientists unveiled a nanowire electrode that could more than triple lithium batteries' energy storage capacity and improve their safety.

The development, reported in the scientific journal Nature Nanotechnology, stems from the labs of nanowire innovator Yi Cui and battery expert Robert Huggins at Stanford's Materials Science and Engineering Department. The researchers show that nanowires of silicon just a few atoms across can function as high-capacity electrodes, absorbing and releasing about 10 times more lithium ions than the graphite electrodes that are commonly used today.

Charging a lithium battery usually means moving lithium ions from the battery's positive electrode or cathode into its negative electrode or anode. Silicon has the right electrochemical affinity for lithium ions to make it a promising material for anodes. In fact, until now, it has been a bit too promising. Silicon anodes absorb too much lithium. Upon charging, the silicon anodes swell to four times their previous volume, fracturing the material. After just a few charging cycles, the anodes are finished.

Nanowires, in contrast, take the swelling in stride. The Stanford collaborators' silicon nanowires swell when charged from 89 nanometers wide to 141 nanometers wide and simultaneously elongate, thereby releasing the strain. They show no signs of mechanical failure after more than 20 cycles.

Go to this link to read the entire article (free membership required):
Technology Review: The Authority on the Future of Technology.
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Oregon Elephant:

Go to the link. They now require a free membership and login, but Technology Review is put out by MIT and is an excellent source of information on breakthrough research.

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