In mid-January 2007, General Motors Corp. unveiled its vision for a future world of automobiles driven by electricity. At the center of its commitment to this view is a family of electrically driven propulsion systems dubbed E-Flex.

The "E" stands for the electric motor that turns the wheels, and "Flex" represents the flexibility in fuel sources that can be used to generate the electricity that powers the motor, including E85, biodiesel and synthetic fuel. The E-Flex system is being engineered specifically for small and mid-size cars, the first of which the company is calling the Chevrolet Volt.

The Volt isn't GM's first foray into electric vehicles. In 1996, the company launched the EV1 to comply with California's zero-emissions vehicle mandate. The company ultimately disbanded the program, an act that became the focus of a 2006 documentary, titled "Who Killed the Electric Car?"

"The EV1 ‘died' because it had limited range, limited room for passengers or luggage, couldn't climb a hill or run the air conditioning without depleting the battery, and no device to get you home when your battery charge ran low," says Robert Lutz, GM vice chairman of global product development. "The Chevrolet Volt is a new type of electric vehicle. It addresses the range problem, and has room for four to five passengers and their stuff. You can climb a hill or turn on the air conditioning and not worry about it."

This will all be accomplished with a 6-foot-long, 375-pound, T-shaped lithium-ion battery located down the center of the vehicle and under the rear seats. The battery can be fully charged by plugging it into a 110-volt outlet for approximately six hours, which is expected to deliver 40 miles of all-electric city driving. To extend that range, a one-liter, three-cylinder, turbocharged engine—fueled with E85, gasoline or even potentially a fuel cell—would create enough electricity to replenish the battery. For a 60-mile daily commute, drivers could expect to average approximately 150 miles per gallon. GM aims to roll out the Volt by 2010.

In the meantime, the company has been conducting durability tests of lithium-ion batteries from two companies, A123Systems Inc. and Compact Power Inc., using an advanced computer program that duplicates real-life vehicle speeds and cargo-carrying conditions. "Production timing of the Volt is directly related to our ability to predict how this battery will perform over the life of the vehicle," says Frank Weber, global vehicle chief engineer of the Chevrolet Volt and E-Flex Systems. "The challenge is predicting 10 years of battery life with just over two years of testing time."

The company is also preparing to integrate the batteries into test vehicles, called mules, for on-road tests. "Extensive analysis in our battery labs is an important step in proving this technology," Weber says. "We expect to further validate these batteries when they are integrated into engineering development vehicles."