New 2021 Model S battery cells & packs

[lolachampcar]

How does Tesla define "fully redesigned"? It seems the car, physically from the outside, is identical to the one that preceded it. In every single possible way. I'd be very wary of Tesla's loosey-goosey use of the term "redesigned". It seems marketing and bull***t have coalesced.

I've been crawling all over my Plaid and am amazed at just how much has changed with the car still looking very similar.

The body shape is similar but the panels are all different. Wheel arches have been pulled out and down. Tires are now better framed in low needing only minor lowering to be perfectly framed. The suspension is phenomenal. They have dramatically changed how they impart forward loads into the chassis and appear to have addressed some of the design issues that drove salt induced corrosion failures on the previous cars. Neutral throttle lateral grip is way up while "feel" is down from both the front and rear of the car. It seems like there is less rubber isolation in the tire to chassis path as I hear more tire noise than before but overall the car is much quieter. Driver position has changed dramatically. Instead of sitting in my old P90DL I feel like I am sitting on the Plaid.

I agree fully that the car appears the same but every one of my senses tells me it is a completely different car. If I could not see the car and could only go on my other senses I would recognize the BeV power delivery but would think it a completely different car.

 

[lolachampcar]

Lots of questions answered.

 

[BM3B]

It’s 99 kWh, they removed 336 cells.

 

[ellielo]

Lots of questions answered.

Thanks for sharing!

 

[emailforbrett]

I’m sure this is a dumb question, but Chemical Engineering is not my forté.

Instead of cylindrical batteries, why can’t they make them rectangular cuboids (like 9v batteries)? With all right angles, it seems they could squeeze more surface area, ie more chemical energy, into each row and column of the battery packs.

 

[MorrisonHiker]

I’m sure this is a dumb question, but Chemical Engineering is not my forté.

Instead of cylindrical batteries, why can’t they make them rectangular cuboids (like 9v batteries)? With all right angles, it seems they could squeeze more surface area, ie more chemical energy, into each row and column of the battery packs.

View attachment 725431

The trend has been a move to larger and fewer cylindrical cells. If you open up a 9 volt battery, you will find it contains 6 cylindrical AAAA batteries.

 

[BM3B]

I’m sure this is a dumb question, but Chemical Engineering is not my forté.

Instead of cylindrical batteries, why can’t they make them rectangular cuboids (like 9v batteries)? With all right angles, it seems they could squeeze more surface area, ie more chemical energy, into each row and column of the battery packs.

View attachment 725431

Two reasons:
1. The jelly roll (google "battery jelly roll")
2. Cooling (google "tesla battery cooling")

 

[lolachampcar]

I find myself putting a lot more emphasis on the chemistry, anode and cathode performance over the physical packaging. I'm sure the change in cell size will bring value but it seems the larger package will need the benefit of improved cell design/performance to work within the current heat rejection scheme. I do not think you can work the current cell technology as hard as they are now using the larger cell format. Internal resistance will have to fall more before that is possible.

Any cell experts here????

 

[miimura]

Lots of questions answered.

Summary:

The Tesla Plaid pack uses 7,920 18650 cells arranged in 5 modules that have an 72P22S arrangement each. (total of 72P110S)
Same BMS system as Model 3/Y. It is capable of sustained 2300A output at a max voltage of 462V (That's over 1 megawatt!).
Each module is 15 3/8" (390mm) long X 55 1/4" (1404mm) wide X 3" (76mm) high. If you include the coolant manifolds and lines, the width is 57 3/8" (1458mm).
This pack's data obtained from the BMS:
Beginning of Life Pack Energy: 99KWh
Nominal Energy Remaining: 32KWh
Nominal Full Pack Energy: 95KWh

 

[lolachampcar]

If someone had told me ten years ago there would be a docile every day BeV capable of 1 Megawatt energy delivery....................

 

[MarcG]

I find myself putting a lot more emphasis on the chemistry, anode and cathode performance over the physical packaging. I'm sure the change in cell size will bring value but it seems the larger package will need the benefit of improved cell design/performance to work within the current heat rejection scheme.

This, plus agressive thermal management - which Tesla has done a great job with improving from the previous Model S.

 

[Dave EV]

I’m sure this is a dumb question, but Chemical Engineering is not my forté.

Instead of cylindrical batteries, why can’t they make them rectangular cuboids (like 9v batteries)? With all right angles, it seems they could squeeze more surface area, ie more chemical energy, into each row and column of the battery packs.

Non-cylindrical batteries are called prismatic batteries.

Basically everyone but Tesla is using large-format prismatic batteries. Mainly because they haven't figured out how to cost-effectively assemble packs made of lots of small cylindrical cells.

In theory there can be some energy density gains by volume by using a prismatic cell - but you usually need/want a bit of space around the cells, anyway, to make it less likely that you will have a run-away thermal event if a cell fails in a bad way or is damaged.

At the cell level, cylindrical cells are far cheaper to manufacture and since cost is a major limiting factor to EV adoption, Tesla has decided that cylindrical cells are the preferred format and that the 4680 has the best balance of cost, performance and safety.

 

[emailforbrett]

Non-cylindrical batteries are called prismatic batteries.

Basically everyone but Tesla is using large-format prismatic batteries. Mainly because they haven't figured out how to cost-effectively assemble packs made of lots of small cylindrical cells.

In theory there can be some energy density gains by volume by using a prismatic cell - but you usually need/want a bit of space around the cells, anyway, to make it less likely that you will have a run-away thermal event if a cell fails in a bad way or is damaged.

At the cell level, cylindrical cells are far cheaper to manufacture and since cost is a major limiting factor to EV adoption, Tesla has decided that cylindrical cells are the preferred format and that the 4680 has the best balance of cost, performance and safety.

Thank you. This makes sense. I figured cost may be a bit higher because the simple fact it is likely easier to create a long roll of the three layers (cathode, separator, anode) in cylindrical form than it would be to wind them in prismatic form. I knew the cylindrical cells were cooled with fluid between the curved outer surfaces, but I thought maybe they could leave a small gap between the flat surfaces of the rectangular cuboid shaped batteries.

I think the above is possible….more energy per total space occupied from rectangular cuboid batteries, but the cost increase negates any gain in stored energy.

 

[2101Guy]

General question: Ford's Mach E Performance GT only gives you full power for a brief burst. Audi/Porsche is similar. Other EV companies have "boost" buttons somewhere on the steering wheel to give temp full power.

Tesla's appear to just give you unlimited full power at all times.

What's the engineering difference (specifically) that allows Tesla to do what the others cant do, re full power at all times

 

[LargeHamCollider]

Better thermal management and higher margins. what the other companies are doing is for marketing purposes, Tesla doesn’t need to engage in such marketing schemes.

 

[2101Guy]

Better thermal management and higher margins. what the other companies are doing is for marketing purposes, Tesla doesn’t need to engage in such marketing schemes.

Thanks...can you elaborate a bit on the "higher margins" aspect?

 

[Krash]

One way to interpret this is that Tesla has economies of scale and a profitable business. Also, as opposed to a dealer model where the dealers make money when your car is repaired or warrantied, Tesla really doesn’t want to see you at the service center. So their cars are frequently over engineered.

You can see Tesla’s approach to torque and power limits when they do things like uncork all the cars from a year back. Or put the 980 performance motor in a bunch of non performance cars just because it is cheaper than making a weaker unit initially.

Other manufacturers are losing money on a limited number of EV cars that they are only making in order to wave the eco friendly flag. Those manufacturers lose money on those cars. They’d lose even more if they put more into engineering.

 

[lolachampcar]

I think it is a combination of a lot of things.
As others have noted, Tesla has doubled the size of the heat pump in the car which lets them remove a lot more heat when discharging and charging the batteries. The S now charges in the range of 900-1000 miles of range per hour for a very large part of the charge curve. Instead of laying down at 40-50 mph, the new car now accelerates all the way up without reducing current draw from the battery. Both of these things require managing more heat from the battery.
Also, Tesla continues to develop their cells. On the last battery day they described all the different paths they were taking to increase capaicty one of which was the reduction of internal resistance. A reduction in internal resistance allows you to move more current through the cell for a given amount of heating (both charging and discharging being the movement of current).

NOTHING comes close and most certainly nothing is remotely close to the value being provided.

 

[ICUDoc]

General question: Ford's Mach E Performance GT only gives you full power for a brief burst. Audi/Porsche is similar.

I drove a Taycan, didn't see such a button. I thought Porsche says "all the power all the time"? That was one of their chief selling points before Plaid- they could do lots of high-power runs end-to-end?

 

[2101Guy]

I drove a Taycan, didn't see such a button. I thought Porsche says "all the power all the time"? That was one of their chief selling points before Plaid- they could do lots of high-power runs end-to-end?

Apologies. Audi Etron has the boost mode which temporarily allows the full advertised horsepower.

The 2022 Audi e-tron GT generates 469 horsepower, or up to 522 horsepower in boost mode for 2.5 seconds with launch control, and 464 lb-ft of torque (472 lb-ft in boost mode).

Taycan utilizes "overboost" for 2.5 seconds of the max advertised horsepower.


Overboost only kicks in when you're using launch control. It doesn't matter how hard you press on the throttle. So The Turbo has 616 horsepower with up to 671 hp worth of overboost power and the Turbo S has 616 hp with up to 750 hp of overboost power.

Tesla has figured out how to give you the full advertised HP all the time, full time. No "boost" gimmick to game the 0-60/HP numbers game like the others are doing.