The Volt: An Electric Car That Could Change Everything

Image Gallery 150 miles per gallon, what a concept! General Motors hopes to produce the Chevrolet Volt as soon as advanced battery technology is available. GENERAL MOTORS

General Motors unveiled the Chevrolet Volt concept car in early 2007, electrifying the automotive world and exciting those clamoring for revolutionary progress in sustainable transportation. A stylish and sleek coupe with room for four, the Volt also happens to be a plug-in electric vehicle with fuel economy up to 150 miles per gallon. If GM builds it — and that’s still a big if — the Volt could usher in a new era of practical electric cars for the masses and go a long way toward helping America end its much-lamented but ever-growing addiction to oil.

What makes the Volt tick is General Motor’s new E-Flex system, which uses an electric generator, an electric motor, an advanced lithium-ion battery pack and a three-cylinder internal combustion engine. The keystone of the E-Flex system is the battery pack, which consists of hundreds of individual lithium-ion cells and the software that manages them. The batteries can be fully recharged by plugging the car into a standard electrical outlet for about six hours. The small gas engine powers the electric generator, which has two functions: recharge the battery pack when needed and provide extra juice to propel the car at freeway speeds.

The "flex" in E-Flex is twofold: the gas engine is flex-fuel, meaning it can burn gasoline or E85 (85 percent ethanol, 15 percent gasoline); and the E-Flex drive is flexible such that it can use a diesel engine or a hydrogen-powered fuel cell instead of a gas engine.

But regardless of whether it’s a conventional gas engine or a futuristic fuel cell, that component of the E-Flex system does not directly power the car. Its role is to power the generator, which provides electricity to propel the car and/or recharge the batteries when needed. That’s how the Volt would differ from current gasoline-electric hybrids such as the Honda Civic Hybrid and Toyota Prius, which are much more dependent on gas. Their electric motors supplement their gas engines; either the motor or the engine can directly power the vehicles.