Probably, Can’t really comment on sound levels I always listen to music when I drive.
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Model Y - Gigafactory Texas Production
- Thread starter Ron J.
- Start date
ZenRockGarden
Active Member
It's an interesting and detailed piece, except the whole thing is built on the single assumption about WH per 4860 cell which he even admits is just a rumor. A far simpler explanation is that the base pack is 828 cells and puts out 70 KWH, with a future option of a LR pack at around 966 and presto 82 KWH.
The need to invent a never-seen, never-EPA-tested 3rd smaller pack fails Occam's Razor for me. It's a much more complicated explanation when there's a very simple one standing right there.
They are literally shipping (to employees) finished 4680 packs with 270 miles of range. Why on earth would they be doing that using secret smaller 3rd version of the pack while showing a half dozen cut open examples of an 828 cell pack that's not in use?
But you saying that it takes 828 cells to make ~68 kWh doesn't match with what Tesla claims for the cells. (They claim 5x the energy of 2170s, which are ~18 Wh.) So the ~90 wH per 4680 cell lines up pretty well with what Tesla has shared.
If you are correct and it takes 828 cells for ~68 kWh would mean that Tesla has failed pretty badly on their 4680 plans.
ZenRockGarden
Active Member
Do you honestly believe that a power point slide from over a year ago estimating the 4680 cell at 5x more capacity than the 2170 (of THAT time) means that you can take the 18 Wh of -todays- 2170 (which is up from what it used to be) and multiply by exactly 5.00 to get the field performance of the 4680 cell as seen in final production form?
Also... if the MYAWD is being made with a secret pack that uses additional plastic blocks to eliminate another 100-odd cells... why does it weigh so much in the EPA cert? Just how heavy are those fillers?
Here's the realistic math. The 4680 comes in just under 90 Wh because it didn't hit exactly 5.00 times the capacity of todays 2170. Call it 88 Wh. 88 x 828 == 72 KWh. Save 3 KWh operating margin to not run the pack to dead 0 (same as is done in the 2170 LR pack), and bingo - 828 cells gives you the MYAWD 69 KWh 279 miles exactly as shown at Giga Texas event.
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The new factories have the GEICO paint shop. Fremont will not anytime soon, just as @bkp_duke says. It is monumentally difficult to retrofit that line, but quite easy, for Tesla that is, in a new factory. Skipping all the technicalities that si because the new GEICO approach has zero reusability with an old-technology paint shop. The new ones can and do produce entirely new and unprecedented colors too.
They are vastly cheaper and cleaner than traditional paint shops. As for retrofit I'm tempted to say 'impossible' but in Tesla world anything might be possible.
The 2170 cells chemistry have a higher power density, hence better performance. 4680 have less power density/energy, therefore less performance. However, the trade off is the 4680 batteries are lighter and can be charged to full more routinely.
buddhafree
2022 MYP
I could be wrong, but based on what I've heard 2170 and 4680 have similar chemistry (not iron) and have the same issues with increased degradation when fully charged.
The 2170s have higher lithium content, while the 4680s have higher nickel content. The 4680s have 5X more energy than a single 2170 cell but 4680s are also 5x larger. 2170s are more energy dense due to chemistry which is also why they are heavier.
Clever marketing by Tesla to say 4680s have 5x more energy while omitting they are larger and less powerful cells.
Hence the performance/acceleration is less in the 4680 model Ys.
ZenRockGarden
Active Member
The performance drop is almost certainly because it just a smaller pack.
Given the continuous-tab design of the 4680, I'd expect it to eventually handle a bit more current (and thus power) than similar-size 2170 pack.
The pack size primarily only affects range. Performance is generally the same weather you have 70% charge or 100% excluding significantly low states of charge.
Relatively speaking the power difference is minimal but still noticeable.
ZenRockGarden
Active Member
Of course pack size directly affects range. But it also is tightly correlated to power output. Simply put, you can extract power faster from a larger collective lump of lithium and nickle than from a much smaller lump.
Look no further than the absurd Hummer - 9000 pound car with 3 second 0-60 because it was necessary to put a stupid-large battery in it to get any meaningful range. As a side effect of the enormous battery, you can extract obscene power levels.
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The cells Tesla was making at the time did not have as much energy today. The original 2170s had ~16.9 Wh/cell. * 828, you get 70kWh. Throw in a couple rounding errors, and 68kWh from 828 cells is in line with those claims.
bkp_duke
Well-Known Member
Tesla's own battery day presentation says you are . . . well just flat out wrong.
5X the energy, but 6X the power.
Makes sense from a "first principles" reasoning as well. 2170 is a wet battery electrode chemistry. Gotta have space for that solvent. 4680 is a dry battery electrode, so the "jelly roll" as it is called can be wound more tightly, and therefore it is more dense.
bkp_duke
Well-Known Member
False. Pack size affects more than just range. Larger kWh packs can charge at a faster rate. Well documented, and makes sense (there are more cells to disburse the current to, therefore your overall current can be higher).
SageBrush
REJECT Fascism
SageBrush
REJECT Fascism
This is not even close to being true
ZenRockGarden
Active Member
It's not 5x more energy dense, it stores 5x more total energy (due to being 5x larger).
The larger diameter is less space-efficient, which they're making up for with improved details in the cell construction as you note.
The 6x power is a slight improvement - very likely from the continuous-tab making lower resistive losses in the cell.
Remember battery day was more than 1.5 years ago and at that point 4680 cells were still in the R&D phase. The production 4680 cells may differ from what was anticipated back then, due to cost or manufacturing constraints. Therefore. any numbers/claims made back then as to performance may simply no longer be valid. At this point we really do not know what is the performance of the actual production 4680 cells.
I think the fundamental question is if the 828 cell battery shown at CyberRodeo is the one used in the new MY Standard AWD (the most likely case since that is the MY version currently being build in Austin) or is for the MY-LR. Those assuming it is for LR come up with a very different set of performance numbers than those that assume if for the Standard AWD model.
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bkp_duke
Well-Known Member
I didn't say 5X more energy dense. I just said 5x the power (yep, volume is 5X bigger than a 2170), and 6X the power.
ZenRockGarden
Active Member
I hear you. Just making sure others understand. It's not 5x the energy density or power output. It's more like 1.0x for energy, and 1.2x for power (when measured against the similar volume of 2170 cells)
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