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Model 3 Battery Speculation

Discussion in 'Model 3' started by J1mbo, Apr 3, 2016.

  1. J1mbo

    J1mbo Member

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    [​IMG]

    The animation behind Elon shows 8 modules building up the battery. We know from previous comments that the M3 battery will be smaller, both physically and in capacity, so how are they able to get an EPA of 215 miles out of such a small battery?

    Let me start by saying that I am not convinced that the M3 will be 40% lighter than a base S85, or massively more aerodynamic. The curb weight of the S85 was about 2,100kg. The M3 is "20%" smaller, but a lot of the aluminium has been replaced by steel, so IMO it is unlikely the car body is much lighter.

    Anyway... the RWD S85 had an EPA of 265 miles. It did this with 16 modules, i.e. 16.5 miles/module (or 5.3kWh/module).
    For simplicity, let's assume that the full 85kWh is used (we know it is not).

    If the M3 had the same power consumption, it would need 13 "S85" battery modules (69kWh) to get 215 miles, or about 7.5kWh/module. This is far more than the ~5% improvement we saw with the new chemistry used in the 90kWh battery.

    So what have they done to reduce power consumption by so much?

    One area of improvement which would save weight and energy could be battery cooling - Patent 20150244036 describes a heat pipe system for cooling & heating which I don't remember seeing in a Model S battery, and Patent 20140193683 describes a "battery pack base heat exchanger". Are we seeing some of this tech already in the Powerpack modules...?

    Any other ideas how they might have done this (and allowed room for a bigger capacity battery as well!)?
     
  2. Yggdrasill

    Yggdrasill Active Member

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    It's already known that the Model 3 will use a different cell format. The 18650 cell format will be replaced with something like a 20700- format (20 mm diameter, 70 mm length).

    And I think it's possible to get 215 miles with 60 kWh, so each module would need to have 7.5 kWh. That seems plausible to me, considering the new format *and* a newer chemistry.
     
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  3. Donar

    Donar Member

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    The Model S 60 kWh has an EPA range of 208 miles.

    I think the Model 3 will be a bit lighter and a bit more aerodynamic. Not by a huge amount, but a 10% reduction in weight and CdA over the Model S would be enough to achieve an EPA range of >220 miles with a 60 kWh battery.

    Some guesses:

    I think there is also going to be a 80 kWh battery pack.

    Maybe...
    60
    60D
    80D
    P80D

    By the time the Model 3 arrives on the market, the S and X are likely to have 80 and 100 kWh batteries.
     
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  4. Saghost

    Saghost Active Member

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    I think you're making this too complicated. As far as I can see, there's no reason to expect that the Model 3 modules have any connection to Model S modules - in fact, there are a number of reasons to think otherwise, including the different cell format cited by a prior response.

    Keep in mind, drag is two pieces - drag coefficient and cross sectional area. The 3 is significantly, visibly smaller than the S - so even if it had the same coefficient, it'd have a notably lower drag load simply from the smaller size. I actually think Tesla has made significant improvements to the coefficient, too - there's no reason they would have chosen that nose geometry for aesthetics.

    Second, starting from the 85 is probably not the best choice - the 60 and 70 are significantly more efficient for reasons that aren't entirely obvious and by an amount that exceeds the weight difference (and doesn't seem to be directly tied to the discussion about the actual capacity of an 85 kWh car.)

    Even in a Model S, the 70 kWh pack manages 230 EPA miles, and the 60 gets 208. From that, 215 is only a 3.3% improvement - I actually expect the 3 to reduce consumption by significantly more than that, which makes me wonder if the 3 base battery is really a full 60 kWh.

    Fishing through the solid model in the background, I really don't see any opportunities for adding extra sections on the the battery pack space, so I think 8 modules are all you get for the battery, whatever size they are. However, I don't think there's any reason to assume that what they showed you on the screen is the base car - especially considering we know that the cars they gave rides in are the AWD upgraded models.

    Given that a lot of the speculation has been centered around a 60 and an 80, what if that's the 80 kWh pack they showed you, with ~10 kWh modules? A 60 kWh pack could easily be made with 6 modules instead... (though that'd also mean 3/4 the voltage, which is presumably somewhat lower than the voltage of a Model S 60/70.)
    Walter
     
    • Informative x 1
  5. NeverFollow

    NeverFollow Member

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    Current Model S base price:
    MS___70____$70,000
    MS___70D___$75,000 (+ $5,0000
    MS___90D___$88,000 (+ $13,000)
    MS__P90D__$108,000 (+ $20,000)

    Just a Model 3 base price guess:
    M3____60____$35,000
    M3____60D___$40,000 (+ $5,0000
    M3____80D___$53,000 (+ $13,000)
    M3___P80D___$73,000 (+ $20,000)
     
  6. ELRev

    ELRev Member

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    D upgrade officially cheaper on the 3.

    Elon Musk on Twitter

    Makes sense. The more I hear, the more excited I become about what I'll be able to afford. Can't wait for full specs and pricing.
     
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  7. RidgeRacerJM

    RidgeRacerJM Member

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    ludicrous!
     
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  8. rnelsonee

    rnelsonee Member

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    Yeah, I'm a cheapskate so I wasn't really expecting to pay for AWD or a larger battery. But <$5,000 for AWD, and one that makes the car more efficient (running motors at ideal temps overcomes weight penalty) and I'm pretty much sold on AWD now.

    And if the Gigafactory 1 produces cells as cheap as Tesla wants, I'm expecting the larger battery to be much less than the $12k or so they charge for the S now. If it goes down to $5,000-$7,500, that's looking like a pretty good deal.
     
  9. AWDtsla

    AWDtsla Active Member

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    You didn't scale... anything.
     
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  10. MartinAustin

    MartinAustin Active Member

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    Here's another relevant tweet, in regard to the aerodynamics he says of the cD:

    hopefully 0.21

    Compare with 0.24 on the Model S and X.

    My own math on this subject... subject to error :)

    The 85KWh Model S has a 265-mile EPA range based on 291Wh/mile, i.e., using up 77KWh to do 265 miles, and leaving 8KW behind (or 9% of the battery) for reserves.

    If the Model 3 also used up 291Wh/mile, it would take 69KWh to travel 215 miles, assuming a 9% reserve.

    But, with its narrower tires and improved aerodynamics and power electronics... let's assume the Model 3 can use as little as 250Wh/mile. (this is 55mph, level ground at sea level, etc. etc. per the usual range criteria for Model S).

    It would use about 53KWh for 215 miles, and with 9% in reserve that would be a 60KWh battery.

    If the Model 3 uses even less than 250Wh/mile - perhaps 200Wh/mile - it could go further, or require a smaller battery.
     
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  11. starlord111

    starlord111 Member

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    The big question will be how much will be a replacement battery in 10 years time for the M3 model?
     
  12. Saghost

    Saghost Active Member

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    10 years is a long time, and a lot can change. However, if Tesla is still building compatible spares at that point I have trouble believing it'll be a terribly large number - unless you want the 1000 mile upgraded version, of course. ;)
     
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  13. Thomas Edison

    Thomas Edison Member

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    Speculating on something that's that far in the future has got to be really difficult. It all depends on so many factors.

     
  14. MartinAustin

    MartinAustin Active Member

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    Not to be negative, but that isn't really the big question.

    How much is a 10yr-old Infiniti G35 worth, and who cares?
    How much is a 10yr-old BMW 328i worth, and who cares?
    How much is a 10yr-old Mercedes C320 worth, and who cares?
    How much is a 10yr-old Audi A4 worth, and who cares?

    There aren't a lot of people asking that question before they buy. Not sure why it's that important for Model 3 either.
     
  15. starlord111

    starlord111 Member

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    These cars will be good for many years, unlike gasoline engine cars, electric motors can go on forever. So if a battery swap will cost lets say $10,000 its a big deal, at least for me. Of course the prices will drop in the coming years.
    Also Tesla will have monopoly on batteries so we will have to buy Tesla batteries.
    By the way I fully support the company, just wondering long term.
     
  16. Saghost

    Saghost Active Member

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    Best guess is it'll cost Tesla around $10k to build the pack for a Model 3 at introduction. Ten years later, the costs should be much lower. If Tesla sticks to their plan of not making a profit from service, I don't think it'd be half that to the consumer - in 2030 or so. (A similar Model S pack cost Tesla close to $20k in 2012, prices fall over time and the Gigafactory is designed specifically to drive prices down.)
     
  17. Lerxt

    Lerxt Member

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    It's not going to need a 10 year battery swap.
    As for a non-Tesla battery, that will never happen. Why would they allow a Chinese company to produce cheap, exploding, low quality batteries and ruin the reputation of the car?

    It's a Tesla, not a Samsung phone.
     
  18. CarlitoDoc

    CarlitoDoc Member

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    I agree with Starlord 111 in the fact that these vehicles have less "wear and tear" issues compared their ICE counterparts. "If" someone keeps it for 10 years, I see a $8-10K "new" battery pack as a pretty good deal, you're basically getting a new car.
     
  19. zer0cool

    zer0cool Member

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    I think 60 and 80kwh make good sense. If the 60 is at say 215, then the 80 would be around 280 (285 - 5 due to greater weight). The P80D should achieve 4 sec 0-60 or even a bit less (say 3.8 or 3.9) but with maybe a 270 range.

    I think these would be perfect specs. I think D will be cheaper, as Elon has said. So maybe 60D would be only 38k start. 80D probably 50-52k, really very similar to 340i or C43. P80D will not be as fast as a Model S P90D, and will start at 62-65k, closely matching BMW M3 and MB C63.

    I think these pricing points match competitors. With a car that performs better in real life situations and SIGNIFICANTLY better tech and other factors, comparatively the Model 3 will be the far superior car.
     
  20. AWDtsla

    AWDtsla Active Member

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    12k estimated for a Model S battery pack after 8 years, which would be 2020.
    12k*(50/85kWh)*70% cost reduction from gigafactory = $5k.

    First Model 3 battery replacement for purchase probably in 2025. If the 7% on average YoY improvement in batteries continues, then we have:
    5k*(.93^5)= $3400
     

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