Due to a slip up by an automakers’ pictures clearinghouse on Monday, photos of the production model of Chevrolet’s new electric “Volt” car were leaked onto the internet.

The Chevy Volt concept, which uses an electric motor to drive the car, and an internal combustion engine to recharge the batteries if no other chargers are available, has been showcased since 2006 at a Detroit Auto Show. The car shown in Detroit however, looked a lot different from the current one. It had a slick angled appearance, and was a two-door coupé.

Chevrolet have stated that the older model, for all its cool, was an aerodynamic disaster and they had operated changes to the look of the car. Exactly what those changes were, however, has been up till now a closely guarded secret.

All that changed on Monday, when due to a mistake by clearinghouse Wieck Media, pictures of the current production model of the Volt have been released on the Chevrolet website for just 12 minutes. Chevy immediately caught and removed the pictures, but that was sufficient for the pictures to be downloaded by scores of users and posted online on such sites as thecarconnection.com and others.

The changes shown are remarkable: the car is now a four-door sedan, with a rather conventional look.

Even though the look is completely different, the production Volt still retains the concept version’s lithium-ion battery pack which is either chargeable from a standard 115/230 V outlet, or from a small internal-combustion engine which will take over and charge the batteries where other sources of electricity cannot be found. A full charge reportedly takes the car about 40 miles. Due to the fact that the combustion engine does not provide drive for the actual car, it cannot be classed as a hybrid.

Even though the leaked pictures may have ruined the surprise, the car’s unveiling in showrooms is set for late 2010/early 2011.