General Motors (GM) is planning to shut down its Detroit-Hamtramck Assembly plant for an entire month to better prepare for production of the 2012 Chevy Volt, as well as the 2012 Opel Ampera and 2013 Malibu, which has a stated 38 mile per gallon fuel economy. It’s not uncommon for plants to have extended periods of down time, usually in the summer and winter, and the automaker is using the time to upgrade tools, equipment, and conveyor systems to increase production of its latest models.

Currently, the Volt is only available in California, New York, Connecticut, Maryland, Michigan, New Jersey, New York, Texas, Virginia, and Washington D.C., however, the company says the plug-in hybrid vehicle will be available nationwide and in China and Europe by the end of the year.

image via General Motors

GM is claiming the plant upgrades will allow Volt and Opel production to increase by 16,000 units this year, and that by 2012 global production will be 60,000 vehicles, the majority of which will be rolled out in the United States. The facility is also being used to make good on the manufacturer’s promise earlier this year that test-drive models of the Volt will be available in every state.

As we’ve noted several times in the past, the Volt can drive 35 miles in all-electric mode, powered by a 16 kWh lithium-ion battery. Although the Nissan Leaf has a range of 100 miles, the Volt can travel and additional 344 miles due to its unique gasoline system, a benefit some consumers find to be essential in a new car.