2012 Tesla Model S prototype

2012 Tesla Model S prototype

The ink's barely dry on the Tesla - Toyota deal that gives the startup electric-car maker a new manufacturing home. But today, Tesla's going public with some details on how it plans to use the former NUMMI facility in Fremont, California, to build its mainstream 2012 Tesla Model S sedan.

The former New United Motors Manufacturing Inc. (NUMMI) plant was the old GM-Toyota factory that built vehicles like the Toyota Tacoma and Pontiac Vibe, until the companies ended their joint venture in the wake of the GM bankruptcy last year.

Earlier this month, Tesla and Toyota announced the Japanese automaker would invest $50 million in Tesla, which would in turn acquire NUMMI from Toyota, in a deal that could lead to cooperation on future electric cars from both companies.

In a blog post, Tesla's VP of Manufacturing, Gilbert Passin, says the Model S will follow a more conventional path to the showroom than the Tesla Roadster, which has a body fabricated by Lotus in England, and is teamed with its battery packs and motors in nearby San Carlos, Calif. The Model S sedan--the vehicle that won Tesla $459 million in loans from the U.S. government, to encourage green-car development--will have its body panels stamped at the factory from aluminum sheets, will go through Tesla's own paint booth and quality traps, and will be built essentially from scratch in California.

The Model S' body will be glued, welded and riveted together, according to Tesla's blog post--a technique that sounds like a blend of typical car manufacturing, and the semi-exotic construction style used for Jaguar's aluminum cars, like the 2011 Jaguar XJ sedan, not to mention the way airframes are assembled.

Tesla also says the Model S' suspension and powertrain assemblies will come in relatively few pieces that can be fitted into the car in one or two steps. It also hints at a swappable battery pack that could enable the sedan to drive longer distances--something like the business plan touted by Project Better Place. The interior will be fitted in modules, too--from the dash to the rear-facing third-row seat, an unusual solution for a sedan, and one that will need to meet some tough safety standards to make into production.

Tesla's purchase of NUMMI marks a sharp turnaround for the company and for the state. As recently as this spring, Tesla had been expected to pick a former aerospace facility in Downey (an L.A. suburb) for its manufacturing facility. When NUMMI shut down, it ended a long era of mass production of cars in the state, if only for a short time. The deal came together quickly, Tesla says, and though it won't fill the entire NUMMI facility at first, it hopes to grow into the sprawling plant, which at one point could produce more than 200,000 vehicles annually.

Tesla's post today also introduces a little more fudge factor into the timing of the Model S sedan. The company confirms its factory will open in 2012; while it's not confirmed the Model S will be a 2012 model, it's possible the official designation for the new four-door could be as a 2013 model.

[Tesla Motors]