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4680 cell implications

swengl

Member
Dec 19, 2014
522
363
Lynchburg, VA
It's amazing to me that, in the aftermath of Battery Day, no one has really focused on the charging implications of the new cell design. The chart presented, if accurate, would indicate that the 4680 cells should take almost no time to fully charge. If that is the case, the bottleneck will move to the charging infrastructure itself and the amount of energy it can transfer. The fact that the CyberTruck and the Semi would be the only vehicles (initially, at least) to receive the new cell design also makes me wonder if Elon has something else up his sleeve for the rest of the fleet, that will still use the 2170 and the 18650 cells. If I were a betting man, I would put some money on the integration/use of supercapacitors.
 

Cyber_Dav

Member
Nov 30, 2019
145
163
SoCal
Few believe supercaps have any place in the power electronics. They capture and release bursts of energy, so maybe regen and ludicrous mode helpers.

My question is, if the new cells are not ready when Cybertruck starts production, will early Cybertrucks be orphans with lower spec batteries?
 
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Reactions: S3XY and Watts_Up
Jan 30, 2020
176
159
GA
Clarify the “almost no time” deduction.

(I’m still trying to wrap my head around the battery chemistry. Didn’t occur to me to consider time factors yet.)
 

JG T3SLA

Member
Aug 5, 2018
164
210
San Francisco
Few believe supercaps have any place in the power electronics. They capture and release bursts of energy, so maybe regen and ludicrous mode helpers.

My question is, if the new cells are not ready when Cybertruck starts production, will early Cybertrucks be orphans with lower spec batteries?

That's a good question. I'd be inclined to delay purchase a bit to get the new batteries. Seems to be a non trivial upgrade so worth the wait. My presumption is that the ranges quoted for the CT, especially the tri motor, are dependent on these new batteries.
 
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swengl

Member
Dec 19, 2014
522
363
Lynchburg, VA
Clarify the “almost no time” deduction.

(I’m still trying to wrap my head around the battery chemistry. Didn’t occur to me to consider time factors yet.)

The actual amount of time has not been revealed, but this image gives you some idea of the drastic reduction in time to charge.
2020.09-tesla-battery-day-elon-musk-drew-baglino-4680-cell-jelly-roll-supercharging-thermal.png
 

swengl

Member
Dec 19, 2014
522
363
Lynchburg, VA
Few believe supercaps have any place in the power electronics. They capture and release bursts of energy, so maybe regen and ludicrous mode helpers.

My question is, if the new cells are not ready when Cybertruck starts production, will early Cybertrucks be orphans with lower spec batteries?

I won't buy a CT unless it has the newer cells, I will gladly wait a bit longer for that improvement, if needed.
 

swengl

Member
Dec 19, 2014
522
363
Lynchburg, VA

brkaus

Well-Known Member
Jul 8, 2014
7,633
6,162
Austin, TX
My question is, if the new cells are not ready when Cybertruck starts production, will early Cybertrucks be orphans with lower spec batteries?
Every EV is an orphan with a lower spec battery pretty quick. Batteries and the configuration of batteries are always improving.
 

Watts_Up

Active Member
Mar 4, 2019
3,094
2,053
In a galaxy far, far away
Few believe supercaps have any place in the power electronics.
They capture and release bursts of energy, so maybe regen and ludicrous mode helpers.

My question is, if the new cells are not ready when Cybertruck starts production,
will early Cybertrucks be orphans with lower spec batteries?
You can still use it down the hill.... unless Nikola Motors patented it and would sue Tesla !!!
 

swengl

Member
Dec 19, 2014
522
363
Lynchburg, VA
The chart shows that it is actually slower. Just not as slow as sizing the "tabbed" design up to 46x80.
It goes a bit against reason that even though the tabless cells don't have the same heat mgmt issues that the existing cells have, they would take longer to charge. Having many points of contact (being tabless) and thus reducing the distance the energy has to travel would also make you think: this should charge faster than existing cells. The way the current packs are charged, once they are above ~75% charged the charge rate slows to help manage the heat to protect the pack from damage, something that the new cells reportedly won't have to do. Any thoughts as to why all of this would result in a slower charge for the new cells?
 

mongo

Well-Known Member
May 3, 2017
12,862
37,837
Michigan
It goes a bit against reason that even though the tabless cells don't have the same heat mgmt issues that the existing cells have, they would take longer to charge. Having many points of contact (being tabless) and thus reducing the distance the energy has to travel would also make you think: this should charge faster than existing cells. The way the current packs are charged, once they are above ~75% charged the charge rate slows to help manage the heat to protect the pack from damage, something that the new cells reportedly won't have to do. Any thoughts as to why all of this would result in a slower charge for the new cells?

The chart is normalized to make the 21mm speeds identical for the twp types. It's purpose is to show the relative impact on charge speed vs diameter for each specific type, not to compare the speeds of the two types. Otherwise, a 15mm tabbed would extrapolate to be faster than a 15mm tabless.
 

bluhorshue

Member
Mar 24, 2017
44
94
Seattle Wa
I think this chart shows that while a tabless battery charges much faster than a battery with a tab, doesn't it also show that a larger diameter battery takes LONGER to charge. This difference is greatly minimized because it is tabless, but it is still a longer amount of time. The bigger battery suggests slower supercharging, not faster. Maybe this is offset by the energy capacity, but without units I don't think you can draw the conclusion that the new batteries will charge faster, and if anything they might charge slower.
 

ItsNotAboutTheMoney

Well-Known Member
Jul 12, 2012
10,228
7,322
Maine
The chart shows that it is actually slower. Just not as slow as sizing the "tabbed" design up to 46x80.

Well, it's slower to charge a cell, but if the cells allow for significantly increased energy density, increased power density and are much cheaper, then you'd be paying the same amount for more range and faster charging, or paying much less for about the same charging but with more range, or somewhere in between.

Personally, I'll take a cheap long-range electric that's a bit slower to charge.
 

mark95476

Member
Jun 21, 2020
758
399
Bay Area CA
Yes. This graph is saying charge times increases on the new tabless cells are decoupled or virtually independent of the cell size.

I think charge times on the tabless cells will be faster for the same amount of energy (100 kWh). I expect them to be able to sustain higher charge rates for longer.

The chart is normalized to make the 21mm speeds identical for the twp types. It's purpose is to show the relative impact on charge speed vs diameter for each specific type, not to compare the speeds of the two types. Otherwise, a 15mm tabbed would extrapolate to be faster than a 15mm tabless.
 
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mark95476

Member
Jun 21, 2020
758
399
Bay Area CA
It won't. I can see them using the existing proven chemistry and sizing up the cells to get significant immediate benefits on existing products.

It goes a bit against reason that even though the tabless cells don't have the same heat mgmt issues that the existing cells have, they would take longer to charge. Having many points of contact (being tabless) and thus reducing the distance the energy has to travel would also make you think: this should charge faster than existing cells. The way the current packs are charged, once they are above ~75% charged the charge rate slows to help manage the heat to protect the pack from damage, something that the new cells reportedly won't have to do. Any thoughts as to why all of this would result in a slower charge for the new cells?
 

CyberGus

Not Just a Member
May 5, 2020
718
1,594
Austin, TX
Personally, I'll take a cheap long-range electric that's a bit slower to charge.

If a battery pack can be charged from 10% to 90% in the same time it takes to fill a gas tank, say 10 minutes, then Range Anxiety Syndrome drops to zero. That's big ask (400 amps! lol) but incremental improvements in charge rate will improve BEV adoption.
 
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Swampgator

Active Member
Apr 27, 2016
1,551
3,041
Florida
I think this thing should be able to charge at 3C rate. That means if it's a 200 kwh pack it can charge theoretically the whole pack in 20 min. More likely to 80% in 20 min with taper. 400 miles of range in 15 minutes is pretty damn impressive.
 

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