chevy-voltBefore the holidays, VentureBeat caught wind that General Motors would be making a big announcement about its highly-anticipated plug-in vehicle, the Chevy Volt, on Jan. 7. Today, it looks like that news will be that the automaker is rolling its first specially-built lithium-ion battery packs for the Volt off the assembly line — bringing the vehicle, slated to launch in California sometime this year, a step closer to reality.

This is set to be a big event, attended by U.S. Secretary of Energy Steven Chu and Michigan Governor Jennifer Granholm. Considering the starpower, the Volt seems to be the first, and most significant leap toward advanced transportation so far, leading the charge of other green vehicles from major carmarkers like Nissan and Mitsubishi.

But this isn’t the most significant thing about GM bringing batter production online. Rather, General Motors is about to become the first major automaker to own and operate a battery pack manufacturing plant of its own — a major landmark in the industry. Having received $241 million in federal stimulus funds, the company is spending about $106 million on its battery pack factory in Brownstown Township, Mich.

GM’s idea is to import more cheaply-made lithium-ion battery cells from Korea’s Compact Power and assemble them into the requisite packs in Michigan, boosting employment for people in the Detroit Metro Area who may have been laid off from auto companies during the economic downturn in 2008 and 2009. The Chevy Volt itself, and its four-cylinder engine, are also going to be assembled at two separate facilities in the local area.

The battery packs are by far the most important part of the Volts, costing about $8,000 alone — GM is estimating about $500 per kilowatt-hour. This is what has raised the car’s price tag to $40,000. But as battery technology advances, these numbers should come down considerably, making the Volt one of the first green vehicles to become a practical buy for the average middle-class family.

Here’s a rough schematic of the Volt’s battery pack structure:

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