Thursday, March 1, 2012

A breakthrough in car batteries opens the 300 mile electric car future







Envia Systems has announced that it is able to produce rechargeable lithium-ion batteries with a world-record energy density of 400 Watt-hours per kilogram. Li-ion is the standard kind of rechargeable batteries that go in everything from phones to electric cars.

Envia says its new manganese-based cathode design allows lithium cells to store almost three times the amount of energy per charge than today’s commercial lithium-ion battery packs. Envia’s lithium-ion batteries use a Silicon Carbide (Si-C) nanocomposite anode, High Capacity Manganese Rich (HCMR) nanocoated cathode

According to Envia, the best commercially-available Li-ion battery has an energy density of around 245 Wh/kg, so this new technology almost doubles that. This is good. Moreover, most Li-ion batteries operate at about 100-150 Wh/kg. The batteries in the Nissan Leaf, for example, have an energy density of about 120 Wh/kg (24 KWh/200kg). Tripling that density would, in principle, triple the range of the Leaf, taking it from around 100 miles to around 300 miles, a range close to a typical gasoline-powered car.

Envia is a joint investment between the U.S. Department of Energy and General Motors has enabled a breakthrough in lithium-ion cell technologies that could cut the price of electric vehicle batteries in half.

Envia is Armed with $7 million from from General Motors’ venture investment arm, G.M. Ventures, and $4 million from the Energy Department’s advanced energy research program, ARPA-E, along with a further $10 million from other interested firms during the same 2011 equity investment round.

The California-based Envia Systems announced that it had created a battery pack with cells with energy density far greater than other technologies on the market. Not only that but better still, Envia claims its new battery technology is more than 50 percent cheaper than current generation electric car batteries, costing around $125 per kilowatt-hour.

“In an industry where energy density tends to increases five percent a year, our achievement of more than doubling state-of-art energy density and lowering cost by half is a giant step towards realizing Envia’s mission of mass market affordability of a 300-mile elerctric vehicle,” said Envia Systems Chairman and CEO Atul Kapadia.

That’s a breakthrough that hasn’t gone un-noticed, even if the battery technology might still be a few years from implementation in a production electric car.

However, the use of lithium batteries for EV and PHEV fleets in large numbers has raised concerns about lithium supply and future availability of lithium in large quantities. In comparison even to known global reserves, the demand from EVs is very small. If, as an extreme example, by 2040, all of the world’s 2 billion cars are FEVs, the total lithium used would be ~3 x 2 billion kg, or 6 million tons, which is equivalent to less than 25% of the world’s known reserves. Hence, there does not appear to be any case for long term supply shortages.

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