• Aug 25th 2009 at 2:00PM
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Tesla Model S in motion - Click above for high-res image gallery

Let's compare: the battery pack in a Tesla Roadster today is 53 kWh. The pack in the Chevy Volt? 16 kWh. The Nissan LEAF? 24 kWh. The Hymotion/A123 kit to make your Prius a plug in car uses a 5 kWh battery. Now, how big might the battery in the highest-range Tesla Model S be?

When Tesla revealed the Model S back in March, they said that the car would be available in three flavors: versions that had ranges of 160, 230 and 300 miles. The standard pack, it was revealed, would be 42 kWh, with "70 kWh and greater battery storage systems optional." Jim Motavalli has now gotten Tesla's chief technical officer, J.B. Straubel, to give a first public estimate of how big the 300-mile pack will be: 85 to 95 kWh.

Motavalli easily found plenty of skeptics willing to criticize a pack this big: it'll be too expensive, take too long to recharge and weigh too much, they said. Straubel's response: we have three years to figure this out, and battery technology advances quickly. Sure, but still, 95 kWh? Yikes.

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[Source: New York Times]

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    • 1 Second Ago
      • 6 Years Ago
      Actually, the story was reported by AutoblogGreen in January:

      AutoblogGreen entry, January 17, 2009

      “The other surprise is a pre-paid battery replacement deal. The current cost of replacing the Roadster battery pack is $30,000! That may be the first time that Tesla has publicly acknowledged the replacement cost of the battery. Owners can now pre-pay for a replacement battery pack at a cost of only $12,000. Tesla has previously said the Roadster pack should last five years, but is now quoting seven years. It’s not clear what kind of condition they expect the battery to be in after seven years. Considering these are laptop cobalt oxide cells and the pack is being cycled through most of its range, odds are it won’t be anywhere near full capacity. If the batteries need replacement before the cost can be driven down, this deal could end up costing Tesla a lot of money.”


      Greg Blencoe
      Chief Executive Officer
      Hydrogen Discoveries, Inc.
      • 6 Years Ago
      "Straubel's response: we have three years to figure this out, and battery technology advances quickly."

      Good, I hope they do figure it out. In the mean time, GMs Voltec drive train makes more sense since it's 40-mile range covers the daily trips for 82% of commuters with a pack that's 1/5 the size, weight and cost of the Tesla Model S.

      A FIVE FOLD increase in battery pack size, weight and cost of the Tesla Model S is a LOT just to cover the other 18% of drivers who's daily commute exceeds 40 miles and they will STILL need fast-charging for long trips in excess of 300 miles.
        • 6 Years Ago
        Well Polo,

        I guess we'll just have to wait for 3 years to see where the Model S is priced and what kind of battery pack it comes with. 3 years is a LONG time when you consider how fast battery technology is progressing. In 3 years, the whole world can change.

        The best laid plans of mice and men and yes, we do live in interesting times.
        • 6 Years Ago
        "A FIVE FOLD increase in battery pack size, weight and cost of the Tesla Model S is a LOT just to cover the other 18% of drivers who's daily commute exceeds 40 miles"

        Lets put things in perspective. You get a FIVE FOLD increase in range with no compromises in power, design, or capacity for only $15K more. The Model S is built and priced for luxury EV buyers. It would be attractive for someone who might by a BMW or Mercedes. Its not average car buyers...thats what the Model T is for.
        • 6 Years Ago
        Tim: The batteries that the GM Volt is using are quite different than the batteries Tesla is using. The Volt batteries have a higher power density and higher cycle count but a lower energy density by weight. While the Volt battery is half the weight of the Roadster battery, it has less than 1/3 the energy. Therefore, a Model S battery with 5x the energy storage compared to the Volt would not weight 5x as much! More likely, a battery with 6x the capacity weighing 4x as much, but who knows what battery breakthroughs could happen in the meantime...
        • 6 Years Ago
        The base pack is 160 miles, so it already covers more than the 80% the Volt covers. 160 miles is probably 90+% of drivers.

        Ideally we can move away from needing a "range extender" and Tesla is pushing us in that direction. The only reason we need range extenders today is because of battery cost and lack of fast recharging infrastructure. I see a range extender as a interim solution to the problem. It's definitely more practical for today, but I think we still need to push the technology forward so BEVs can eventually get as close as possible to gasoline cars today. Once we have a 300 mile pack, then the "range anxiety" issue frequently mentioned by skeptics of BEVs is greatly diminished (though in actual practicality, a 300 mile battery is probably overkill) and the next step is working on rapid recharging and reducing cost.

        If you directly use the current 53kWh pack @ ~900lbs weight then a 85-95kWh pack would be 1450-1600lbs, which is too heavy for most vehicles. However, given the Roadster uses 2.4Ah cells, they still have room to move to higher density 3.0Ah cells which would bring the weight down to 1160-1280lbs. 3.6Ah seems to be the cutting edge, which will bring it down to 1000-1100lbs. So a 300 mile range Model S is certainly doable (though it'll be expensive). If they don't go the removable battery route, it's a good chance the battery pack will be used as part of the structure to reduce overall vehicle weight.
      • 6 Years Ago
      I don't see any problem with more capacity. It'll need a longer charging but where is disadvantage compared to a smaller pack? Because there will be more range it doesn't mean it has to be topped everyday. Now imagine having 200kWh (or 500kWh for that matter) and flexibility it'll give. Such charge can be build on a surplus charging every night. With better batteries we will get better available charging options too. 95kWh is simply stunning and it will not be last word of battery technology.
        • 6 Years Ago
        @B : "I don't see any problem with more capacity... imagine having 200kWh"

        Weight, size, and cost. LiFePO4 cells at 100 Wh per kg according to Wikipedia means 200 kWh of them would weigh 2000 kg -- 4,400 pounds! You have to put all that material somewhere. And the cost...

        Presumably you're hoping that the research for greater battery density at lower costs pans out. Me too.
        • 6 Years Ago
        Of course - 200kWh is out of practical reach now. Yes - I'm hoping tech like air fueled lithium batteries could be commercialized eventually. It'll take some time but as history shows technology improvements tends to speed up with every next cycle. With Roadster it was 53kWh, now with Model-S 95kWh then how many kWh there'll be next?

        Good thing is even 200kWh could be available only in high cost sport luxury cars, it means 50kWh should inexpensive enough to fit a normal commuter.
      • 6 Years Ago
      when I first saw this car I knew right away that the weight was very wrong. it's an unsustainable weight and a big step in the wrong direction. I think it might well be a miscalculation that can kill them. 450$ million dollar debt riding on the succes of a 1700+kg electric car being a mass seller.

      they have/had an opportunity to pioneer high strength low weight materials but they went with a conventional soft heavy steel approach and even flaunted the stupidity by making it heavier than even normal cars. it's all wrong. mark my words.

      I expect the basic model will end up costing high 70s and the largest costing 100k. and that's assuming a positive case scenario where they don't collapse under the panic of the bad decision well before it gets to actually delivering the cars.

      if it had a range extender like Fisker Karma then maybe. maybe.
      there are only so many wealthy people willing to pay top dollar for a limited practicality car because they have several other cars in backup.

      they still have time to change it to fiber reinforced plastic and drop all the parts that are of the old heavy clumsy thinking. drop the wheels, they are too heavy, drop the disc brakes, they are too heavy, hubs, chassis, diff. then do it all with components aimed for a target weight of well under 1000kg. maybe 600kg. same design.
      • 6 Years Ago
      Even though batteries get less than 10% more capacity per year for the same price, I'm gonna be nice and say this pack will probably cost the same as the original Tesla pack, which was $30,000.

      That says to me that this car, with all the other costs increased (due to more material) won't cost any less than the Roadster in this configuration. Another $100,000 car. Wow, that's great.

      And the pack will weigh even more than the Roadster pack. This in and of itself would cut the efficiency (miles/J) noticeably.

      Maybe when Tesla stops using laptop batteries things will look up a bit. They have so far said the Model S would still use laptop batteries, but maybe they have plans to change this.
        • 6 Years Ago
        Don't be silly. The Model S won't be built with expensive carbon fiber body panels, the way the Roadster is, and probably won't have a bonded aluminum frame, either. Using a more conventional construction method will bring the cost down quite a bit for the Model S.

        The Tesla Motors team does have some experience, now, so their initial estimates of $50K for the price of the Model S shouldn't be too far off the mark.
      • 6 Years Ago
      I love coming across discussions like this.
      It reminds me of old discussions you can find archived online from the 90s where people talk about the impossibility of gigabytes of ram in computers, etc.... and how this is not possible and that will never happen due to costs or physics barring the discovery of any new technology and all kinds of things...etc... etc...
      Luckily there are a lot of engineers and scientists out there who just keep their heads down and working along and not listening much to the heckling and chatter behind them.
      • 6 Years Ago
      Cells are already available in the standard 18650 form factor that would boost the Roadster's pack up to 65KWH. That should boost range to 290 for that car.

      The batteries are constantly improving. I'm looking forward to upgrading the pack in 5 to 7 years and getting 500 miles or more.
      • 6 Years Ago
      I totally agree that 95 kWh is a lot. But we will have to get used to that number because that is what we ultimately want, or more for a typical car. The issue is the weight of course and that is the surprising part to me, and probably everyone else. Fast charging at home or at utility stations (electric stations), will be what sets the overnight large kWh problem to rest, I feel. The only way I see large >100kWh battery packs becoming viable (price and effective range) is if the weight is dropped substantially, in say ultracapacitors or nanotechnology. Not a huge leap of faith to imagine, I guess. The future has such potential! Good on Tesla for taking the first step. As a side note, I also like range extenders based off of advanced generation biofuels.
        • 6 Years Ago
        You are right I was thinking of passenger cars when I mentioned >100 kWh. But yes some electric trucks already have much larger capacities. Combination are good, but there are avenues for some fully ultracapacitor packs, Eestors perhaps if they come through, not to mention that is what the next X-prize (based off of their contest they did last year) will be. They will see who can build the best ultracapacitor. Take care
        • 6 Years Ago
        @Geoff de Ruiter
        "The only way I see large >100kWh battery packs becoming viable (price and effective range) is if the weight is dropped substantially, in say ultracapacitors or nanotechnology."

        130KWh batteries already exist in the Smith Newton 12t lorry.

        Super-capacitors are good for quick charging but they have little energy density, i.e. they are good for regenerative braking not for long term storage like batteries. Bolloré is working on a battery+capacitor combo.

      • 6 Years Ago
      Hi Stan,
      Don't be so sarcastic and ironical, just have a look at:

      http://www.ogron.eu/en/technology.html ....and smile contently.

      • 6 Years Ago
      Surely future electrical cars will have large batteries. It will quickly as development allow higher energy density (KWh/Kg) and falling battery prices. Once more luxury cars enter the electric car market we will be seeing battery sizes well beyond 100KWh.

      However for the charging system it is important to prepare for this future and not just aim a charging standard at what is needed for a small hybrid car battery like in the GM Volt.

      Actually the future of large batteries has already arrived. The British Smith Electric Vehicles which build lorries with electric drive have batteries up to 130KWh. These are charged by IEC 60309 plugs (3 phase 230V at 32A), i.e. the same electrical specs that the Mennekes plug is based on.


      Using EV plugs standards that are proposed for US (SAE J1772) and Europe (Mennekes), how fast could a battery this size (130KWh) be charged, with a charger system prepared for max spec:

      SAE J1772: 240V up to 70A charging max 16.8KW = 7h44mn
      Mennekes: 3 phases 230V up to 63A charging max 43.5KW = 3h00mn

      I.e. for a working day with a lunch break and some loading in the middle of the day, you can with the Mennekes plug drive 2 routes per day with the lorry, whereas you can only drive one route per day when recharging with the J1772 plug.

      Indeed the J1772 is ill prepared for large battery sizes.
        • 6 Years Ago
        "I *think* it's *quite likely* there will be a level 3 (480v 3 phase) standard"

        There is no way you can do 3 phase power, i.e. 3 lines of current, with the J1772 proposed plug so that would be a completely different plug type. Further it would make the J1772 obsolete even before the first car with this plug has been sold. Do you call this a standard?

        "With current sized packs, charging even at 220V/70A is considered to be a bad idea due to it putting a lot of wear on the battery pack."

        Please go back and read my previous comment. 130KWh batteries already exist.

        How to make quickest/best charge is a challenge that each car/battery/charger manufacturer can work on to optimise their system. What is important is that we set an adequate EV plug standard between power grid and vehicle. Mennekes is that, J1772 is not.
        • 6 Years Ago
        Oops, wrong link to the Smith Newton lorry. It should be:
        • 6 Years Ago
        I think it's quite likely there will be a level 3 (480v 3 phase) standard for the J1772 before it's much of an issue. The SAE has already started on it.

        With current sized packs, charging even at 220V/70A is considered to be a bad idea due to it putting a lot of wear on the battery pack. Of course, as packs get larger, the charge rate relative to size goes down at any given current rating, so the typical (and considered reasonable) charge rates will go up.
      • 6 Years Ago
      @ blencoe:

      You have some legitimate concerns, but maybe you can switch
      from Hydrogen to Methanol? I think it makes more sense. Look:

      • 6 Years Ago
      Choice is good. Are the battery packs modular, so Model S owners can get a garage workout adding or removing the additional modules for longer/shorter trips?

      Regarding size, if the BYD e6 crossover really has 400km range and consumes 18 kWh/100 km, then it must have at least a 72 kWh pack (even bigger assuming it doesn't deplete SOC to 0%). And your article mentioned "a price of just over $40,000". Hard to believe!
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