Automotive Innovation Batteries Included
Stanford students rev up the electric car with laptop power.
When General Motors and Toyota yanked the plug on their electric-vehicle programs last year, citing high costs and weak demand, many proud owners of gas-guzzlers no doubt nodded smugly: Batteries are for flashlights, not family cars.
But now a team of young electric-car enthusiasts is attempting to change that widely held perception by building an experimental battery-powered car capable of highway cruising speeds and cross-country trips–all on a single charge. “We want to dispel the myth that electric vehicles can never travel more than a few hundred miles,” says engineer J.B. Straubel of the Stanford Electric Vehicle Project.
The secret to the project is lithium ion, the same technology supplying juice to most laptop computers. Straubel says booming laptop sales have made lithium-ion batteries cheaper and more efficient than lead-acid or nickel-metal-hydride cells, the power sources for GM’s EV1, Toyota’s RAV4 EV and other now defunct commercial models.
The Stanford car will stow 10,000 lithium-ion batteries under the hood. A standard laptop typically has eight. Wired together, the lithium-ion cells–each roughly the size of an AA battery–will store enough energy to power an average home for four days, says Straubel. More important, the Stanford team calculates the pack could propel its car at an average 45 mph for 2,000 miles, smashing all previous EV records. The team hopes to have the car ready for road tests by July.
What Makes the E-Car Efficient
Built from hollow stainless-steel tubes, the chassis weighs less than 100 pounds and measures 8 feet long, axle to axle. The chassis is covered with an aerodynamic teardrop-shape carbon-fiber shell.
The 10,000 lithium-ion batteries will weigh about 1,100 pounds and hold 80 kilowatt-hours of energy. To prevent the batteries from overheating, 150 microprocessors will constantly monitor their temperature and voltage output.
The wheels are outfitted with Michelin’s custom solar-car radials. Inflated to 100 psi, the tires are made of Kevlar-reinforced rubber and have up to one-fourth the resistance of traditional tires.