In the world of plug-in cars, making an affordable car with a range equal to that of a conventional gasoline car is something of a Holy Grail. 

According to General Motors CEO Dan Akerson talking at a GM employee meeting last night,  that dream could become reality in the next two to four years. 

“I think we’ve got better than a 50-50 chance,” Akerson said, “to develop a car that will go to 200 miles on a charge. That would be a game changer.”

Of course, there are already cars on the market that are capable of such distances.

The 2012 Tesla Model S with an 85-kilowatt-hour battery pack is rated by the EPA at 265 miles per charge. But at $77,400 and up, it isn’t affordable yet.

The battery Akerson is talking about, however, may well be.

Developed by Californian battery firm Envia Systems, the breakthrough lithium-ion battery uses a Silicon Carbon Carbide (Si-C) nanocomposite anode. 

Envia Battery Technology

Envia Battery Technology

Not only is it three times as energy dense as current lithium-ion batteries, but it costs half as much. 

Back in January 2011, GM’s venture capital arm invested $17 million in the battery specialist, betting that it could help the automaker develop cheaper electric car batteries. 

In February this year, Envia released more details of its technology, claiming an energy density of 400 watt-hours per kilogram--far more than the 140 watt-hours per kilogram offered by the battery pack in the 2012 Nissan Leaf. 

The more energy an electric car battery can store for a given weight, the larger its capacity and the further the car can travel.

As Akerson pointed out back in March, an energy-density increase from existing battery technology could mean a car like the Chevrolet Volt could travel as far as 140 miles on a battery pack the same physical size as its current battery pack. 

Or, it could cut the size, weight, and cost of the car's current 16-kWh pack substantially while maintaining the existing 38-mile range of the 2013 Volt.

Volt Battery Pack

Volt Battery Pack

That was the course of action discussed by now-departed Volt engineer Frank Weber before the car launched.

Weber said firmly 40 miles was the right amount of electric range for the daily needs of four-fifths of Volt drivers, with the security of limitless range on gasoline as a backup.

The more affordable batteries could also make a pure battery-electric vehicle practical.

Thus far, the only known GM electric-only project is the 2013 Chevrolet Spark EV, a low-volume compliance car that uses cells from A123 Systems.

Much testing remains before the Envia battery is ready for production cars. And many questions have yet to be answered about how the battery technology would work in future electric cars. 

Acknowledging the caveats, it may be that longer-distance electric cars could appear sooner than many in the auto industry thought they would. 

If so, that can only be a good thing. 

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