By contrast, some plug-in hybrids on the horizon would require motorists to charge their cars in a wall outlet overnight and promise only 50 miles of gasoline-free commute. And the popular hybrids on the road today still depend heavily on fossil fuels.
"It's a paradigm shift," said Ian Clifford, chief executive of Toronto-based ZENN Motor Co., which has licensed EEStor's invention. "The Achilles' heel to the electric car industry has been energy storage. By all rights, this would make internal combustion engines unnecessary."
The result is an ultracapacitor, a battery-like device that stores and releases energy quickly.
Batteries rely on chemical reactions to store energy but can take hours to charge and release energy. The simplest capacitors found in computers and radios hold less energy but can charge or discharge instantly. Ultracapacitors take the best of both, stacking capacitors to increase capacity while maintaining the speed of simple capacitors.
Among other things, the ultracapacitors described in EEStor's patent operate at extremely high voltage, 10 times greater than those Maxwell manufactures, and won't work with regular wall outlets, said Maxwell spokesman Mike Sund. He said capacitors could crack while bouncing down the road, or slowly discharge after a dayslong stint in the airport parking lot, leaving the driver stranded.
By GRANT SLATER,