Double stacked 4680 cells for the Cybertruck long range version?

[Tinker71]

I think this is relevant to this discussion. The CT will use 4680s, which are 14% taller. So effectively the CT battery would be "14% double stacked" compared to a Model S. Taking it a step further, the overall packaging of the new cells means more energy can be packed in the same size pack. Sandy Munro estimated it at around 50% more storage. If you're at 100kWh for a Model X, you're up to 150kWh using 4680s on the CT. The truck is bigger, so maybe you can fit some more cells in there, and you're up to around 175kWh. Then, Tesla estimates the weight savings at 56% from he new battery, and the corresponding range bonus is 16%. That would mean the equivalent of a 200kWh battery with no stacking. That probably gets you to that 500+ mile range, with far less cost, weight and energy use than we're seeing from options like Ram.

I don't recall when, but I think the plan was to truly double stack the 4680 cells not metaphorically. It would be cool if all batteries were rated as "adjusted pack level energy density" This would be kWhr/mass of the entire pack with a credit for structural material that is able to be removed due to the structural nature of the pack.

Sponsored

 

[Tinker71]

The federal credit for LFP cells might not be available today but that might not be true years in the future.

My revervations are so far back in the line that I do not expect to see the first one until late 2025.

Tesla has said they expect LFP cells to be in more than half of all cars & light trucks they sell.

CATL & Tesla are building a battery factory in U.S.
Also other suppliers are talking about building LFP factories in U.S.

In 2025 or 2026, Tesla will probably have access to U.S. made LFP cells.

I would like a double stack of LFPs in my Cybertruck.

Safer (reduced fire risk), use full capacity ( 5%-100%), more charge cycles.

This would solve the standardization problem. LFP can be made cylindrical and could be made in the USA/MCA.

Sometimes I think we might over emphasis the benefits of standardization. If they make 100k of a particular CT and 150k of another, you still have a lot of volume to divide stuff by.

 

[Tinker71]

For what it's worth, they told Motortrend before the prototype reveal that they did intend to have a double-stacked battery on the tri motor. They also intended a double stack on the new Roadster. For single layer they likely wouldn't change the floor height or anything, just fill the extra space with something.

Was that the reveal in 2019?

I think their polyurethane glue could transfer the top cord to the bottom cord pretty effectively, it is just all those connections would have to be made before they brought the upper and lower sheets together. There would be shear forces mixed in there as well. Then you have to cool the pack and add the BMS in a way that you don't loose more than a couple cells in each parallel grouping.

Maybe they solved all of that. I am very excited for that tear down.

This might go down as another CT first. First gigapress over 6000 tons, bent stainless steel body, 4WS and double stacked battery. That is a lot of innovation to bring together at once.

 

[JBee]

I don't think a double stacked battery pack will be very structural.

It's the nature of a truss, or sandwich panel, of which the structural pack is, to use the "webbing" between the top and bottom chords in order to transfer compression and tension loads through the chords. If the webbing in any way shears, compresses, or delaminates from its position on the chord the structure will fail.

As such, two cells stacked with only a top and bottom layer chord is nigh impossible to use to transfer the static and dynamic loads of a vehicle in motion and with payload. The only way to do so would be to introduce a third layer chord between the two stacked cells, otherwise the battery cell walls will not contribute structurally to perform the webbing function in the truss.

But I also believe that the "double sandwich" structural pack is inherently unnecessary, in that the overhead cabin roll cage structure offers considerable rigidity, even with just a single layer high structural pack.

So either the extra range packs are mounted on top (not underneath) of the structural pack layer, or they are in front or behind it, or they don't need them at all.

From a bit of math I did with cell dimensions and pack sizes a fair whole back, together with a side intrusion buffer like on the MY structural pack, I think they can fit around 180kWh under the cabin between the axles, without the vault cover roll interfering. That's around 180kWh and so happens to be 420miles with the current 4680 cells. The 500mile version would be with the future 4680 improvements.

I honestly don't think there will be a full double stack, unless they can't get to the cell performance estimates or they need a towing beast model.

 

[scottf200]

For what it's worth, they told Motortrend before the prototype reveal that they did intend to have a double-stacked battery on the tri motor. They also intended a double stack on the new Roadster. For single layer they likely wouldn't change the floor height or anything, just fill the extra space with something.

Tesla Cybertruck Revealed! Photos + Details on the Wild New Electric Pickup
Christian Seabaugh Nov 22, 2019
Below via: https://www.motortrend.com/reviews/tesla-cybertruck-electric-pickup-photos-info/

 

[MonkeyDeLuffy]

There are about 4 layers of 4680 per pack on Semi, Here is the estimated section view:

Another estimated layout of the 82kWh battery pack:

Double stack 100 kWh is not that far away from us if Tesla can do 4 or more.

 

[ED_SFO]

I think they would prob double stack the battery for tri/quad. Single stack and double stack will bolt up at the same points which makes sense for simplicity. I wonder if they could keep the efficiency to 400 watts per mile.

 

[Diehard]

There are about 4 layers of 4680 per pack on Semi, Here is the estimated section view:

Another estimated layout of the 82kWh battery pack:
Double stack 100 kWh is not that far away from us if Tesla can do 4 or more.

I have a feeling someone in this forum has CT and Semi on order and planing a monster CT mod. No range anxiety on that one..

 

[JBee]

There are about 4 layers of 4680 per pack on Semi, Here is the estimated section view:

Another estimated layout of the 82kWh battery pack:

Double stack 100 kWh is not that far away from us if Tesla can do 4 or more.

But how does the four layer design work as a structural pack? That is the main question really, because they are looking or mass scale optimisation and weight/cost reduction. As above, there's enough space for 180kWh in a single layer that would be structural. That's nearly double a MX pack, but the CT is only going to use less than 30% more than a MX.

 

[charliemagpie]

Whatif Battery Density is much improved?

What is the estimated Wh/kg required in order to achieve 500 miles of range in a single layer pack? Or is this a silly question?

 

[GhostAndSkater]

Whatif Battery Density is much improved?

What is the estimated Wh/kg required in order to achieve 500 miles of range in a single layer pack? Or is this a silly question?

Not a silly question, but a single layer pack would need a 4680 to store around 200 Wh, or more than double than now

Specific energy for that is around 560 Wh/kg, so no, 500 miles won't happen in a single layer anytime soon, maybe when the refresh of the refresh of the refresh Cybertruck version launches in a decade

 

[CyberGus]

Maybe the wiper is actually a battery

 

[JBee]

Whatif Battery Density is much improved?

What is the estimated Wh/kg required in order to achieve 500 miles of range in a single layer pack? Or is this a silly question?

Depending on what the actual figures are, but based on 180kWh fitting in one structual layer doing 420 miles, achieving 500miles would require a 20% capacity upgrade, which is what both Tesla and Panasonic are targeting for their 4680 production. I also expect this to be the way they achieve a 500mile version.

But they definitely don't need twice the density to achieve this. Otherwise you would end up with just 250miles on a single layer, which is silly talk given the CT floor size in comparison to a MX etc.

 

[Ogre]

I was really thinking about a double stacked structural pack with the same footprint as the floorboards. Yes I think partial double stack is possible under the front and rear seats and maybe under the dash somewhere. These probably wouldn't be considered structural.

Batteries under the rear seat would take up storage that would be available on the standard range unit. If there is some space under the dash, I am not sure if it would have been accessible anyway. Handling would be slightly worse.

I guess my point is when you nearly double the pack size between the 300-500 range, one of the base designs will probably suffer.

Hence my original premise. They don't make the 500 mile range until the batteries improve and maybe start with a 400 mile top end.

It is po

Hoping they improve batteries prior to deliveries. How is that Cathode factory doing?

Personally, I kind of wonder if they are doing doublestacked for both medium and long range. With just fewer cells in the medium range version.

I don’t think they would release an interim top end model if they didn’t have the capacity to do 500 miles, I think it’s more likely they would just launch with the dual motor truck and hold off on the longer range model until chemistry caught up.

 

[Ogre]

Maybe the wiper is actually a battery

What people don’t know is BAW hired CyberGus as his agent and is trying to get set up for some big movie gigs. That’s why we see so much BAW promotion from the bear.

Sponsored