The battery swap-out idea is outdated, as is towing a small generator trailer for long trips. Those were proposals that gained traction *before* lithium proved itself safe.
The battery pack of the not too distant future (if designed at the same weight) will give a range of up about 800 miles. This is an example of one such breakthrough (there are others but this is the furthest along the development pipeline).
Nanowire battery can hold 10 times the charge of existing lithium-ion battery
BY DAN STOBER
Courtesy Nature Nanotechnology silicon nanowires
Stanford researchers have found a way to use silicon nanowires to reinvent the rechargeable lithium-ion batteries that power laptops, iPods, video cameras, cell phones, and countless other devices.
The new technology, developed through research led by Yi Cui, assistant professor of materials science and engineering, produces 10 times the amount of electricity of existing lithium-ion, known as Li-ion, batteries. A laptop that now runs on battery for two hours could operate for 20 hours, a boon to ocean-hopping business travelers.
"It's not a small improvement," Cui said. "It's a revolutionary development."
The breakthrough is described in a paper, "High-performance lithium battery anodes using silicon nanowires," published online Dec. 16 in Nature Nanotechnology, written by Cui, his graduate chemistry student Candace Chan and five others.
The greatly expanded storage capacity could make Li-ion batteries attractive to electric car manufacturers. Cui suggested that they could also be used in homes or offices to store electricity generated by rooftop solar panels.
"Given the mature infrastructure behind silicon, this new technology can be pushed to real life quickly," Cui said.
The electrical storage capacity of a Li-ion battery is limited by how much lithium can be held in the battery's anode, which is typically made of carbon. Silicon has a much higher capacity than carbon, but also has a drawback.
Silicon placed in a battery swells as it absorbs positively charged lithium atoms during charging, then shrinks during use (i.e., when playing your iPod) as the lithium is drawn out of the silicon. This expand/shrink cycle typically causes the silicon (often in the form of particles or a thin film) to pulverize, degrading the performance of the battery.
Cui's battery gets around this problem with nanotechnology. The lithium is stored in a forest of tiny silicon nanowires, each with a diameter one-thousandth the thickness of a sheet of paper. The nanowires inflate four times their normal size as they soak up lithium. But, unlike other silicon shapes, they do not fracture.
Research on silicon in batteries began three decades ago. Chan explained: "The people kind of gave up on it because the capacity wasn't high enough and the cycle life wasn't good enough. And it was just because of the shape they were using. It was just too big, and they couldn't undergo the volume changes."
Then, along came silicon nanowires. "We just kind of put them together," Chan said.
For their experiments, Chan grew the nanowires on a stainless steel substrate, providing an excellent electrical connection. "It was a fantastic moment when Candace told me it was working," Cui said.
Cui said that a patent application has been filed. He is considering formation of a company or an agreement with a battery manufacturer. Manufacturing the nanowire batteries would require "one or two different steps, but the process can certainly be scaled up," he added. "It's a well understood process."
http://news-service.stanford.edu/news/2008/january9/nanowire-010908.html And 2 weeks ago the economic question was pretty much settled when Panasonic decided to start manufacturing lithium battery packs for HOME use with renewable energy systems. The larger the market, the more money flows into manufacturing. The more money that flows into manufacturing, the more innovation and supply. The more innovation and supply there is, the cheaper the batteries become.
Panasonic plans home-use storage cell
December 23, 2009 The Yomiuri Shimbun Panasonic Develops High Energy Lithium-ion Battery Module with High Reliability
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Panasonic Corp., which recently made a successful takeover bid for Sanyo Electric Co., plans to market a lithium-ion storage cell for home use around fiscal 2011.
"We'll be the first to bring to the market a storage battery for home use, which can store sufficient electricity for about one week of use," said Fumio Otsubo, president of Panasonic, in a recent interview with The Yomiuri Shimbun.
On Monday, Panasonic announced it has officially acquired a more than 50 percent stake in Sanyo.
It has become Japan's second-largest electronics giant, next to Hitachi, Ltd., with anticipated combined sales of 8.66 trillion yen for the business year ending in March.
Stressing that Panasonic and Sanyo have already test-manufactured a storage battery for home use, Otsubo said, "We're positioned closest
to realizing CO2 emission-free daily life."
By making Sanyo its subsidiary, Panasonic plans to accelerate the development of the storage battery, while planning to sell it together with a system that will enable households to check electricity usage on a home-based TV display.
Solar batteries for home use and fuel cells can generate power but cannot store electricity, making the development of a storage battery an urgent task for related businesses.
"As we now have such power-generating products as solar power and fuel cells, there'll be an opportunity to create a bigger business...In the area of automobile cells, we can deal with all kinds of eco-friendly cars such as hybrid cars or electric vehicles," Otsubo said, emphasizing the synergistic effect of tying-up with Sanyo.
Otsubo said his company will announce its basic ideas with regards to reorganizing the two firms' growth strategies and overlapping product lines--such as large household appliances--on Jan. 8, while presenting specific ways to deal with the overlapping lines of business when the company announces its settlement of accounts in May.
Conceding that product brands of Panasonic and Sanyo need to be unified at some well-timed point in the future, Otsubo said many things need to be considered, adding that the company's new midterm plan would be worked out while keeping Sanyo's brands in place.
With the rise of the yen and accelerating deflationary pressure, the corporate environment remains harsh.
"We'll come up with products sought by middle-income people in such emerging countries as China and India, which haven't been hit by deflationary pressure... We hope to introduce Sanyo products to Panasonic's sales channels," he said. http://www.physorg.com/news180778009.html