The Volt--the car we've all been waiting for--is going to be one of the big stories at the North American International Auto Show taking place next month in Detroit.

General Motors sent out an e-mail blast today stating that GM and government officials will make a landmark announcement regarding the Volt battery on January 7 at 9:30 EST. If you've never been to Detroit, early January truly is the best time of year to visit.

Much we already know. The Volt will have a 16 kilowatt/hour battery largely engineered by Compact Power, a joint venture that includes South Korea's LG Chem. (Compact will make the cells--GM will fuse them into a battery pack in a plant in Michigan.)  It has a lithium manganese chemistry, less volatile than those lithium cobalt batteries in your notebook, and it will be based around prismatic (or rectangular) cells instead of cylindrical ones to take up less room. Some experts claim that lithium batteries cost around $900 a kilowatt hour, but rumors percolate that GM and Compact will get close to the $500 range. Still, that would be an $8,000 battery, which partly explains why a Chevy will cost close to $40,000.

Both GM and Compact have received DOE grants to lay the groundwork for commercialization of the Volt. Compact got $151.4 million in August while General Motors got $240 million. GM also got billions ("approximately three jagundas" according to one Staten Island car analyst) to stave off death.

What's it going to be? Probably an update on the factory and manufacturing. Maybe pricing. The Volt will be shown off as well.

GM and Ford have also set up an interesting dynamic in plug-in hybrids. The Volt is a series hybrid, a novel architecture that only GM seems to be promoting. Ford's plug-in hybrid will be a power split hybrid, sort of like a regular hybrid with more batteries. GM will likely have better mileage. Ford, though, says its battery will be cheaper, which generally means a less expensive car. Ford won't come to the market with a plug-in until 2012.