Rapid charging not as damaging as first thought, new study finds

Fast charging electric cars might not be as bad for their lithium ion battery packs as first feared according to a new study.

Researchers at Stanford University and the Stanford Institute for Materials & Energy Sciences (SIMES) found that the benefits of slow draining and charging compared to rapid charging, have been overestimated when it comes to limiting the damage to battery electrodes over time. Continue reading Rapid charging not as damaging as first thought, new study finds

Tesla Planning Grid Storage As Part Of Supercharger Expansion

Buy a Tesla Model S, and you won’t need to worry about brownouts. And you could even keep driving through the Zombie Apocalypse.
Tesla Motors CEO Elon Musk revealed that little tidbit at a press conference today, where plans were detailed for an expanded network of the company’s Supercharger rapid-charging stations.

“We actually have grid storage going on at some of our Supercharging stations,” said Musk, noting that two stations in California currently have 500 kilowatt-hours of combined energy storage—with the potential of “putting out a megawatt if need be.”

And that extended grid storage is “probably” part of the long-term plan for every Supercharger station, according to the CEO. Under the scenario, stationary battery packs take in energy through the week from an overhead solar panel array—which in turn doubles as a shelter from sun or rain.

“The chargers are generating energy cumulatively throughout the course of the week, and it cumulatively adds up to more than what the cars consume,” said Musk. “So it’s actually capable of going completely off-grid,” and of continuing to charge cars when the power goes out.

Musk wouldn’t exactly where in California those two grid-storage prototypes are, but he confirmed they’re in California, and that the grid storage is being planned together with utilities, who have received the plan well—as that excess energy could be fed back into the grid when it’s needed, as a buffer to help prevent brownouts or help reduce pollution during off-peak situations.

“Even if there’s the Zombie Apocalypse—seems like a popular theme nowadays—you’ll still be able to travel throughout the country using Tesla Supercharging system,” quipped Musk. “Even if the entire grid goes down, it’ll still work.”

**[Ed. Note: Elon Musk‘s comments may be seen as building on a misconception that the grid is unreliable. Let the record stand: The entire national grid has never gone down, and major regional outages are extremely rare. Also, zombies are not real.]

Electric Car: Tesla releases European pricing for Model S EV saloon

Californian carmaker Tesla Motors has released pricing for left hand drive European versions of the Model S electric executive saloon, with an entry price of under £60,000 depending on the market.

The Model S will launch in left hand drive markets during the first half of 2013, and Tesla’s European arm, based out of Maidenhead, is appointing a team of fleet experts to establish the car in the corporate sector. Right hand drive models will follow later in the year, and prices will be announced four to five months beforehand, Tesla said.

Sold with three different battery packs, the Model S offers up to a 300-mile range and with the Performance pack has an output of 416bhp. It’s based on a skateboard-shaped platform with the battery under the cabin and motor between the rear wheels, offering a low centre of gravity, 50/50 weight distribution and creating space for 50% more boot capacity than of its rivals.

At launch, the car will be available with two of these battery units. The 60kWh unit offers a range of 230 miles on a single charge and costs around £59,000, while the 300-mile, 85kWh version is priced from £68,000 depending on the market.

The top-level Signature trim starts at £83,000, only available with the larger battery, while the 416bhp Performance versions are priced at £80,000 or £90,000 depending on trim. Shortly afterwards, the range will be completed by the entry-level 160-mile, 40kWh unit which could bring prices do to around £50,000. All versions should also qualify for the £5,000 government grant in the UK.

While the car is more expensive than executive-class rivals, its low tax liability could make it a viable option for fleets. The range-topping Signature Performance version offers on-paper acceleration figures to match the BMW M5, Jaguar XFR and Mercedes-Benz E63 AMG, all of which emit 230g/km or more.

New Energy-Dense Battery Could Enable Long-Distance Electric Cars

NATIONAL HARBOR, Md.—A company founded in the Palo Alto public library has taken a dose of government money and technology and turned it into the most energy-dense battery ever. Envia System##Q##s new lithium-ion battery packs roughly twice as much energy per gram as present batteries, the company will announce here at the third annual summit of the Advanced Research Projects Agency—Energy (ARPA–e).

“We achieved 400 watt-hours per kilogram,” explains materials scientist Sujeet Kumar, Envia co-founder and chief technology officer. “We have made a 40 ampere cell in a large format that automakers can recognize and use,” and one that has been validated by independent energy density tests at the Naval Surface Warfare Center in Crane, Ind.

With a $4 million grant from ARPA–e, the Envia technology builds on work done at Argonne National Laboratory that found that including manganese in a mix of materials for the cathode—the electrode to which the lithium ions flock—better energy densities could be achieved. The team then switched focus to the anode—the electrode from which lithium ions flow to produce the electric current—and boosted its performance by incorporating silicon along with the typical graphite.

By blending silicon with carbon, the researchers claim to have gotten around the problems of silicon anodes that have disabled other batteries ability to charge and discharge time and time again. Simply put, silicon swells. “It will hardly last 10 cycles because of the high volumetric changes,” admits Kumar. But by encasing it in a carbon coating—as well as interlacing carbon fibers—the Envia team argues it has surmounted that problem and its battery has cycled 400 times—and counting. “Even if the silicon pulverizes in the first cycle, connectivity is maintained through the carbon fibers,” Kumar adds, though that impacts the voltage.

Then there is so-called “thermal runaway,” an engineering euphemism for batteries bursting into flame—a persistent problem with energy-dense storage devices based on lithium-ion technology. This is particularly true in cars where batteries must undergo a test in which an 8-millimeter nail penetrates the battery at speed. Envia claims its batteries pass that test. “It##Q##s mainly that the cells are much thinner,” Kumar says. “It##Q##s very easy to remove the heat,” though it will be up to each individual automaker whether they want to employ air or liquid cooling of battery packs.

The slim, energy-dense batteries developed at an Envia center in China could reduce the number needed per car by half. And the batteries are cheap at $125 per kilowatt-hour, less than half what current batteries cost, an expense that contributes some 65 percent of the cost of an electric car. But, in addition to further independent testing, the Envia battery must now embark on the multi-year process of testing by actual car-makers. GM is an investor, but Envia declines to identify who is interested. “We are working with all the brand name [carmakers] around the world,” says Atul Kapadia, Envia chairman and CEO. The idea is to either form joint ventures to produce the batteries in tandem or to license the technology to pre-existing partners.

But, assuming a single nail doesn##Q##t bring down the new technology, the battery could boost the range of electric vehicles, such as GM##Q##s Chevy Volt. The more watt-hours per kilogram, the farther an electric car can travel. That means a Nissan LEAF boasting Envia##Q##s batteries might be able to travel the 300 miles between St. Louis and Chicago on a single $10 charge, rather than the roughly 80 it can travel today. “We expect Envia##Q##s next generation lithium-ion battery will revolutionize the [electric vehicle] industry by eliminating the three remaining barriers to mass adoption: cost, range and safety,” Kumar said in a statement announcing the breakthrough. “The ability to drive up to 300 miles on a single charge will eliminate ##Q##range anxiety.##Q##”