Detroit 2011: Tesla Model S "alpha build" prototype explodes the secrets of electric vehicle engineering

Tesla Motors' time in the media spotlight at the Detroit Auto Show today was a bit of a rehash of stuff we knew already – 1,500 Roadsters sold thus far; the Model S is a tremendous bit of engineering – but that doesn't mean we didn't enjoy seeing Peter Rawlinson, Tesla's vice president and chief engineer for vehicle engineering, present the silvery Model S Alpha Build Prototype.

The prototype was gussied up a bit for the show floor, but this is the same thing that the engineers are using in the vehicle's first testing phase. Tesla says the Alpha test phase checks the Model S "under extreme conditions for brakes, suspension, driving dynamics, fit and finish, and safety requirements." The next step is, surprise, the Beta test phase, about which nothing was divulged. With this presentation, Tesla is trying to push the idea that, on top of efficient batteries and excellent design, the company also has a strong engineering team. You can see what we mean after the jump.

Live photos (excluding top photo) copyright ©2011 Sebastian Blanco / AOL

The specific details of the Model S remain the same: the car is scheduled to be released in mid-2012 and will cost $57,400. What's interesting is that Tesla spokesman Ricardo Reyes called the Model S a "very economical car." You'll probably get a lot for your money, but it's still a chunk of change. Also, it's money well spent, since Tesla is using everything it has learned from the Roadster in the Model S, Reyes said.

Now, about that exposed frame. You can see in the picture that the exploded view really shows off the ultra-thin battery made up of over 7,000 li-ion cells that sits at the bottom of the car. This shape is the same no matter what range battery pack you choose for your Model S –160, 230 or 320 miles. Rawlinson said that the engineers haven't decided if the lower-range packs will house fewer cells or if it will use a full complement of lower-density cells. Performance and economics will be the deciding factors for this decision, he said. Of course, since the Model S was designed with battery swaps in mind, drivers will be able to exchange their pack for another one in a fashion that's yet to be determined.



On top of the battery sits the aluminum-intensive body structure. This body structure embodies Tesla's new in-house-designed platform that will spawn other vehicle variants (think SUV, aka the Tesla Model X). Rawlinson said that the structure uses an innovative spot welding, which helps save weight. "Aerodynamics, weight saving; these are the gifts to range in an electric vehicle," he said. "Weight saving is a cornerstone of the Tesla philosophy." Another special feature of the Model S is the Tesla-designed suspension system, which Rawlinson said is "readily suited for mass manufacturing." The low center of gravity means the car has light-duty sway bars, which improves the ride quality and the overall noise and vibration. "This is so important for an electric vehicle."

We've already seen some of Rawlinson's presentation in this series of videos about the Model S, and we still heartily recommend those as a way to pass a few minutes. You can watch them here.