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Tesla Model S Alpha Build Prototype – Click above for the high-res image gallery

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.


Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype


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.

tesla model s alpha prototype

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.


Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype

  • Tesla Model S Alpha Build Prototype
  • Tesla Model S Alpha Build Prototype



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    • 1 Second Ago
  • 27 Comments
      • 4 Years Ago
      Great technology, but Tesla doesn't make a dime. I cringe at the thought of all the venture capital money that goes into companies like these. Most of these companies are just trying to get bought buy a larger company or sizzle out into bunkruptcy. Larger manufacturers can do all this cheaper and faster if they thought there was money to be made....there is isn't right now, hence the building of concept after concept.
        • 4 Years Ago
        "there is isn't right now, hence the building of concept after concept."

        They have a product is called the Tesla Roadster.

        They have been working on the Model S for some time now because they are I believe are trying to get it right (which is good) rather than rush it out in production.

        It is important also for them to price it / build it differently as this car is to marketed to a different market (luxury car market) than the Roadster buyers (exotic sports car market).
      • 4 Years Ago
      and What's with the third row of seats ?

      I don't know or understand their demographic targets, but aiming for people that want minivans or station wagons?
        • 4 Years Ago
        Elon has four or five kids and he is the vision behind the car. He wants a luxury car that he can fit his entire family in.

        Guess Tesla doesn't think a minivan is part of their company image.
      • 4 Years Ago
      Any reference to the nVidia chip to save energy.... :)
      • 4 Years Ago
      yeah insurance is bad news for every aluminum bodied car

      One thing that surprised me, that besides being aluminum, it is a very conventionally designed unibody. Sure, some nice details like the beam between the strut towers, and use of some extrusions and castings; but overall pretty conventional in concept.

      And those huge and heavy brakes in the rear? Seems like with regen, they could have used some little drums off a Geo Metro.

      But it is a 3800 pound beast ??? last I heard?
        • 4 Years Ago
        There were some videos posted earlier, in one of them their CTO (I think) explains that they've found out they need bigger brakes because the low CG of the car results in less load transfer to the front wheels during braking.
        • 4 Years Ago
        EV nerd,

        the rear rotor is large because 1) the CG is low so there is more load on the rear tires during braking relative to an IC powered car and 2) the rear brake system likely packages a drum-in-hat parking brake that is probably 190-220 mm in diameter which fits inside the rotor.
      • 4 Years Ago
      There is no reason to think that Tesla has no good engineering team. Tesla Roadster speaks for itself.

      Where I'd put a big question mark, though, is Tesla's industrial potential. It's still a small company, without strong production capabilities. That severely limits their options when it comes to use of non-generic parts, or high volume and low cost manufacturing (not a problem for Roadster but let's see how it works for Model S).

      Examples of such decisions (only those I'm aware of):
      - use of generic 18650 cells.
      - inability to design a 2-gear transmission that "doesn't break".

      There is a reason why almost all small premium brands nowadays are divisions of larger car makers.
        • 4 Years Ago
        Timo: losses in the motor and output stage of the inverter are strongly current (torque) dependent. At low speeds, where the motor produces little output power but is driven with relatively large currents the total efficiency is nowhere near 90%. BTW, where did you take this figure from, I have a suspicion that it is just one of these numbers (90%, 99% etc) that get abused all too often.

        This low speed and high torque scenario is what you constantly get when driving in a city. Because of range limitations this is the main application people use EVs for, yet this is exactly the range of speeds at which single-speed drive train is the least efficient. This is very easily fixable, though - just add one gear ratio tuned for typical city drive and leave the other unchanged (or slightly increase) for motorway use. Even if you use the same motor, you'll operate it at lower torque, which will scale down the torque/current related losses.

        Point taken about the scaling of the motor itself (so that the car has a reasonable acceleration at motorway speeds). However, this problem can (and I'd argue that it should) be addressed by scaling the output power not the torque. A smaller faster running motor will produce the same output power as a stronger but slower one, yet still be more efficient when the maximum power is not needed.

        Another thing I agree with you is adding complexity to the mechanical part of the drive train. Transmissions (letting alone CVTs or hydro-kinetic torque converters) loose a substantial power (this time as a fraction of the output power). That's why I think the transmission should be integrated with a differential - you still want to use a differential, if only for reducing RPMs and increasing torque, or you will end up with funny looking motors.

        A transmission is not the only solution, you can get a similar effect by playing with motors:
        - By using two motors. One with a larger magnetic core and more windings (for reducing currents at low speed, high torque operation), perhaps with a directional clutch. Other with a smaller core and fewer windings (for high speed operation).
        - By using a single full size motor with switchable windings (old technique with delta-star or with serial-parallel winding configurations). This is like putting a "transmission" in front of the motor. The output torque stays fixed but you can greatly decrease electric losses at low RPMs (by presenting a higher impedance to the inverter).
        • 4 Years Ago
        I like this car, it's looks, and everything. However when you look at all the issues with the roadster, the transmission, the continually increasing price, and how few they have sold.


        I dono man.
        • 4 Years Ago
        There is NUMMI and the Tesla-Toyota partnership. Toyota and Daimler are both investors in Tesla and actively covet Tesla's battery design and field data. That is a likely new source of revenue for Tesla (battery pack design and operational data) as it is key to any competitive EV.

        Model S will proceed to mass production under the tutelage of investor Toyota.
        • 4 Years Ago
        Yeah Bill, I always think 'Back to the Future' when Tesla crops up.
        The Roadster is quite an acheivement, but I can't see the company having staying power.
        Tesla cannot be considered in isolation from US Government policy, which to it's credit is attempting to sponser electric mobility.
        Unfortunately, politics being involved, that does not mean that they are going to put the money into viable projects.
        So you have hundreds of millions going to companies like Tesla, and in the battery field, 123, which are both essentially bit players.
        How they can compete long term with the likes of LG in batteries, or Nissan in EV cars, has never been clear.
        So you have a lot of US Government money going into essentially boutique companies, whilst the centre of batteries, and hence electric vehicle development, remains firmly in the East, and with massive companies.
        I would not invest your pension funds in Tesla.
        • 4 Years Ago
        Timo: single gear transmission works but it results in an inefficient use of the battery, inverter and motor. You end up with a huge-torque (physically large) motor, huge currents in the inverter and battery to give you enough acceleration at low speeds, and high rotational speed and high voltage at high speeds. As a result you get a maximum power and efficiency peak somewhere (20~30mph) below your maximum speed. At city speeds, where an EV will probably be used most of the time, both power and efficiency are substantially lower than their nominal values.

        Tesla's two gear transmission was a good idea (and I believe EV manufacturers will ultimately wake up to it). The problem with it was - there was no such transmission on the market. Putting in a full-blown 4 or more gear transmission would be an overkill, existing 2 gear transmission were likely designed for non-automotive applications, designing a modern transmission from scratch isn't easy - even larger manufacturers tend to reuse existing designs as much as possible.

        Geronimo: Yes, a CVT is an "ideal" transmission (at least as far as the "function" is concerned). The problem with CVT is that its losses or size or complexity (pick two) are likely to be quite a bit larger than that of conventional types.

        IMO two gear semi-automatic transmission would be more than enough for improving the efficiency to the point that the losses in power supply and drive train don't matter. What we really need is two speed ranges at which all the components work at their nominal power/efficiency, i.e. one for a city drive (~30mph), another for a motorway (~70mph). This is an electric drive train so the peaks are not going to be very sharp so the efficiency would likely be almost flat in the whole usable speed range.

        The transmission itself should IMO be integrated with a differential so that there is only one set of gears between the motor and wheels. This is to minimize losses and noise (they are more "visible" in an EV than in an ICEV due to its inherent lower overall losses and noise).

        Gear shifting should be automatically but on demand. With only two gears it's more like having two "drive modes", one for city, one for motorway. Fully automatic design would be getting in the way by switching gears back and forth too often or too late.
        • 4 Years Ago
        You get pretty flat torque curve for very large portion of the RPM range from 0 - around 5000, max HP you have at around 6000RPM which is about 53mph, engine efficiency at that point is about 90%. I wouldn't call that "efficiency peak", because for entire normal driving speed range you have over or about 90% efficiency.

        In fact I expect that you lose more from transmission losses than you gain in engine efficiency with two-gear setup.

        "physically large" is about 25cm^3.

        For acceleration you need that torque, with or without gears. Especially passing acceleration, which is way more important than 0-60 acceleration, highest torque with lowest possible gear for that speed is a requirement. With two-gear setup you would lose in high-speed acceleration, unless you plan to set it up so high that you actually don't need it any more. Tesla gear ratio is pretty much optimal just for that (higher RPM you start to lose torque, which in turn loses acceleration).
        • 4 Years Ago
        Tesla's challenge is to move from hand-assembling a few hundred cars a year to manufacturing tens of thousands annually on an automated production line.

        Historically, the former has proven much easier than the latter (DeLorean comes to mind)

        • 4 Years Ago
        @ Timo:
        A transmission has completely different aspects for an EV than for a conventional ICE. Theoretically, the best transmission type for an EV would be a CTV.
        When an EV is accelerating, the motor draws huge currents from the battery. These immense current flows - albeit of rather short duration - are rather destructive for the battery. A CVT would provide adequate torque and eliminate high current peaks. This would even allow for downsizing of the e-motor and draw even less current which enhances battery life and subsequent overall performance.
        • 4 Years Ago
        They have a former NUMMI factory which was capable of producing over 100 000 cars / year. All it takes to fit the production lines to produce those Tesla cars (and hire people to operate the necessary machinery) to ramp up production way high.

        Getting that factory was like a win in a lottery for Tesla. Incredibly cheap for its capabilities.

        They have now a lot more staff than what they had at the time of "two-gear" failure. IMO even trying to use two gears was a mistake. One gear works better, is more efficient and for driving comfort is much better, you don't have to even think about gears and you get the same torque no matter which speed you are going. It was a lesson Tesla needed to learn, and they have done so.
      • 4 Years Ago
      Tesla is breaking new ground that every single auto manufacturer will have to follow if gasoline reaches $5 a gallon
      • 4 Years Ago
      The so-called Teslal Roadster was really designed and built by Lotus and shipped to Tesla without and engine installed. All Tesal did is hook up an off the shelf electrici motor in place of the ICE and stuff thousands of energizer bunny Lithium cells into every nook and cranny. Some engieneering. Most kit car builders are more advanced.

      TheTesla S is a very different kettle of fish They are trying to design a real car. It is already way late to reach the market. GM, Toyota, Nissan/Renault and and a hoard of other etablished auto makers are rushing product to market. The only guys Tesal might beat are the Gorebul- Fisker troops. But then Hendrick, AlGore and others, are splitting up the half billion of government dollars, which was their real object all along...
      As PT Barnum observed, "Ther is a Sucker born every minute..." and the Graveyard Registrar fits the definition to a "T"
        • 4 Years Ago
        Um, Stan, while Lotus did help Tesla with the design and engineering of the chassis and builds those chassis for Tesla, Tesla Motors designs and builds its own motors and motor controllers, they didn't just slap in something "off the shelf". As for the batteries, they designed a compact battery enclosure that fits neatly behind the seat, just above the motor, they didn't just stuff cells into "every nook and cranny". Where in the world did you get that ridiculous idea from?
        • 4 Years Ago
        The way I see it the Tesla S is more in competition with exotics like Jaguar or Maserati, not Toyota or GM.
      • 4 Years Ago
      Hmmm - you really want to talk about exploding cars with consumer lithium ion batteries ?
        • 4 Years Ago
        Hmm. I take your point. I just saw the open doors/hatch and the battery tray down below and imagined the car being blown apart in slow motion so you can see the inside. Guess there are other ways to interpret it, though.
      • 4 Years Ago
      @Stan Peterson

      That's pretty insulting about the Roadster. It has some incredible electronic engineering, and the motor is definitely not off-the-shelf.

      But, I will agree with you about the Frisker. A government $ boondoggle and blowing a lot of investor dollars.
      • 4 Years Ago
      That battery is awfully large and thin, it comes up quite close to the edge of the car.. I guess insurance may be expensive.
        • 4 Years Ago
        High insurance premiums are not something that people who buy $57,000 luxury cars usually worry about.
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