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A look at the new Tesla cells

11954 Views 124 Replies 14 Participants Last post by  Kevin Sharpe
2170 cells replaces 18650 standard at the Gigafactory.

Doubtful they will be available to DIY community, though. The big boys will probably contract full production.
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Any reliable updates on the 21700 Tesla cell specs?
As others have pointed out, things don't pencil out for the new Semi and R2 to be using today's battery technology.
Yeh, I get that but was more interested in the Model 3 battery and how we might use the salvage :D
The 3.4Ah came out 3 or 4 years ago and there has not been any density improvement by Panasonic (or Tesla) since then.
I thought the 21700 in the Model 3 was 'confirmed' as ~4.6Ah given we 'know' the long range version has 4416 cells and a capacity of either 74kWh (here) or 80kWh (here) :confused:


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Since Model 3 modules built of the 2170 cells are presumably superior to the 18650's in current production models, my guess is that modules which you salvage from Model 3's after they go into actual production will be the same as what will be used in the Semi (and presumably Roadster 2). Or at least the cells in them will be the same.
The Tesla Model 3 battery capacities announced by Elon Musk suggest that the 2170 is 'simply' a repackaging and cost reduction exercise. Clearly a 200kWh battery will not fit in the Roadster 2 without some major improvements in energy density (at least x2). It's hard to know whether Tesla can deliver this in two years, but given Musk has never met a date I guess two years could turn into five and then maybe it's possible :confused:
The 3.4Ah capacity is for a 18650. Now since the 2170 is 1.466x the volume of the 18650, one would expect the proportional capacity for the 2170 to be 4.98Ah. But if the capacity is confirmed at 4.6Ah, then that is a step backward! (Note that the 'chemically usable' volume proportion of the 2170 is actually higher - about 1.5x, which implies a capacity of 5.1Ah.)

The T3 LR pack is estimated at 78 kWh nominal (and 74 kWh usable). 78 / 4416 / 3.6 = 4.9Ah -- which I believe is more likely (than 4.6Ah).
Thanks, that makes a lot more sense :)
I doubt Musk is in any rush to alter/improve the cell performance just yet.
I agree... hard to imagine how we get from here to a 200kWh Roadster 2 battery in two years :confused:
Elon said...
I think that's the problem ;)

All of this would be so much more believable if Tesla actually demonstrated a significant improvement in capacity rather than a change in packaging which, while important, cannot deliver the 200kWh Roadster 2 battery :(
Musk has a history of under promising and over delivering on everything except time frames
Many examples where that's untrue... one obvious example is the Roadster 3.0 upgrade, the majority of which never happened, and the one that did (battery replacement) looks like a $30,000 disaster :eek:
Energy density is a given with time at this point.
Do you believe that Tesla will deliver a 200kWh battery, that occupies less volume than today's Model S battery, in two years time?
Do we know for certain that the preproduction R2s as demonstrated do not have 200kWh packs ?
And if not, what size pack do we think they have ?
Given the demonstration time of a few seconds of acceleration at a time, and presumably minutes of driving for the event, the demo car could have any production battery (including the promised 200 kWh pack), right?
I don't think we know anything for certain about the battery used in the Roadster prototype demonstrated at the event.

Lot's of interesting work going on trying to calculate the size of the Roadster... several people have used pixel counting and know references like size of tyre fitted... the attached image (from here) seems to be typical of the end results :cool:

Ultimately this all hinges on whether you believe what Musk said on the day :rolleyes:


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Could just be a S with 2 100Kwh packs.
Most people have concluded that the Roadster prototype does not have enough height for a double layer battery based on 18650/2170 cells... some people reported "sitting high up" during the test drive so maybe some batteries are under the seats but IMO this car does not have enough space for 200kWh today.

If it's a little heavy so what , add more power.
How much power do you need *today* to get a 200kWh battery, three motors, and four people to 60mph in 1.9 seconds, 100mph in 4.2 seconds, and then top out above 250mph without (presumably) shifting?

With enough time and resources almost anything is possible but I think this car requires a step change in battery technology that Tesla may or may not have achieved. Personally I'll be keeping my cash in my pocket, especially until we see the reality of Model 3 production :rolleyes:
If I'm not mistaken, the R2 has motor based torque vectoring. This implies symmetry, side to side, for the two motors and gear reduction boxes in the back.
Multiple articles have stated that the Roadster has torque vectoring... I'm not sure what the original source of this is but suspect it will be required to get such a heavy car around corners.
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