SAN FRANCISCO — Troubled automaker General Motors Corp. yesterday officially unveiled its battery-powered Chevrolet Volt as part of its 100th anniversary celebration.

Chevy's plug-in hybrid, if it manages to live up to the lofty expectations, could become the new face of a company that's long been known more for horsepower and lots of metal.

The production version is less angular, and in the eyes of some critics, less interesting than the concept model that was the darling of the big Detroit auto show last year.

Design critiques aside, the hype surrounding the planned 2010 launch has only seemed to gather momentum in recent months as demand for more fuel-efficient vehicles continues to grow.

The compact sedan's drivetrain runs solely on electricity and can go 40 miles on a single charge, with another 360 miles or so available when the gas in its small fuel tank kicks in to recharge the battery.

The engine will deliver the equivalent of 150 horsepower with a top speed of 100 miles per hour, the Detroit giant said.

GM still hasn't put a price tag on the vehicle, but some analysts have said it could reach as high as $40,000, about double the cost of traditional compact offerings.

This isn't the first time the public has seen the production model.

GM posted photos of the Volt on its media Web site earlier this month, but blamed that on human error, although some were convinced it was a marketing ploy.

GM is celebrating its centennial birthday against a backdrop of plunging vehicle sales, tightening credit, still-high gas prices and the shakeup of the U.S. financial system.

GM shares sat out the broader market rebound yesterday to finish down 5.2 percent at $10.84.

The stock, a component of the Dow Jones Industrial Average, has lost 68 percent in the past year.