An Argument For Electric Cars

New Battery Could Make Long-Distance Electric Cars Possible

In an article by Scientific American of February 27, 2012 by David Biello, significant improvements in high capacity batteries are discussed. The Advanced Research Projects Agency – Energy announced that Envia System has a news lithium-ion battery pack with roughly twice as much energy per gram as present batteries, 400 watt-hours per kilogram. This achievement has been validated independently through density tests at the Naval Surface Warfare Center in Crane, Indiana.

Envia used a $4 million ARPA-e grant to base its work on the experiments at the Argonne National Laboratory which found that using a mix of materials for the cathode that included manganese achieves better densities. Envia then examined the anode and boosted its performance through inclusion of silicon along with the expected graphite. Coating silicon with carbon gets around the problem of silicon swelling, which limits the cycles of charging to ten or fewer. Envia contends that it can recharge through its coated anode 400 times or more.

Envia has also dealt with the problem of "thermal runaway," which is a euphemism for batteries bursting into flames. Envia uses thinner cells which make it easy to remove the heat.

An Envia center in China has developed slim energy-dense batteries that cost only $125 per kilowatt-hour, less than half the cost of current batteries. This is important because batteries are 65 percent the cost of electric cars. The Envia battery must now move to the multi-year process of testing done by actual automobile manufacturers. Either joint ventures to produce the batteries in tandem or licensing the technology are being considered.

In a statement announcing the breakthrough, Envia said the achievement seeks to "revolutionize the industry by eliminating the three remaining barriers to mass adoption: cost, range and safety," by providing a 300 mile range for electric vehicles.

Summarized from:
http://news.yahoo.com/energy-dense-battery-could-enable-long-distance-electric-230100576.html