# garsh's Official Model 3 Battery Pack Capacity Calculation Thread



## garsh (Apr 4, 2016)

Given all of the recent talk about Model 3 battery pack capacities that erupted after Elon's tweet:

__ https://twitter.com/i/web/status/829002643947167744I decided to attempt an actual calculation of the largest possible battery pack that will fit into a Model 3. So... LOTS of caveats. Since we have no official dimensions of any kind, I'm making a lot of assumptions and educated guesses. So whenever you see me provide a size for something related to the Model 3, it is a guess - an approximation.

First, consider the battery pack from a P100D. It's been hinted that the cell arrangement in the 100D battery pack is a precursor to how the Model 3's battery pack will be organized. So here's a Model S battery pack:








It contains 16 battery modules - two stacked in front, and the rest in a 7x2 arrangement.
Here's what one of those modules looks like from a P100D (with a P85D module above it):








*Model S: Arrangement of Cells in a Module*
There are 516 cells in that module (8256 cells total). Each cell is 18mm in diameter.
From any of the various ebay auctions, the dimensions of a module are approximately 685mm x 280mm.
Looking at the picture above, we see that we have 16 rows of cell, each row with 32-34 cells.
Taking the width of 280mm and dividing by 16, we get 17.5mm.
Taking the length of 685mm and dividing by 34, we get 20mm.
The rows are staggered to allow 18mm diameter cells to be placed 17.5mm apart.
So, I'm going to assume that the Model 3 battery modules will have a similar arrangement, where the cells in a row have about 2mm in between, but the rows are staggered and overlap by 0.5mm.

*Model S: Percentage of the Floor taken by Battery Modules*
Ignoring the two stacked modules, the other 14 modules fit in a space in between the front & rear axles. I couldn't find the dimensions of the entire pack, but seven modules would be 1960mm == 77". The wheelbase of a Model S is 116.5", and the tire diameter is 28.5". Add a few inches within the wheel arches, and that leaves 84" to fit the battery pack. So we have ~7" of overhead between and around the modules. Roughly 10% of the space in between the axles. The width of a Model S is 77.3" (1963mm). Two modules together would have a length of 54" (1370mm). So width-wise, we have about 30% overhead. I'm going to assume that the Model 3 has similar 10% length and 30% width overhead values.

*The Model 3*
Now comes all of the approximations. How big is the Model 3 battery pack? How many modules does it contain? How big are those modules, and how many cells will fit in each module? Let me take a shot at this:

From the Model 3 reveal, we know that the pack will consist of 8 modules. Unlike the S, the 3's modules are arranged so that there are four modules side-to-side, and two modules front-to-back.








*Model 3: Battery Module Size*
Randy Carlson of seeking alpha approximates the size of the modules as 42"x14" (1067mm x 356mm). How did he come up with this? I don't know. Let's try to figure out what fits ourselves. The "approximate" Model 3 dimensions given by MotorTrend (I still think they took a tape measure to the photo shoot, but weren't allowed to say so) are:

Width: 74.2" (1885 mm)
Wheelbase: 113" (2870 mm)
Tire (275/30-20) diameter: 26.5" (673 mm)
Let's take 70% of the width (52", 1320mm), divide by 4, and we get module widths of 13" (330mm).
Take wheelbase - tire diameter (86.5"), remove a bit more for wheel arches (82.5"), and then remove 10% overhead, to get 74.25" (1886mm). That gives module lengths of 37" (940mm). So, we'll assume that the modules are 37"x13" (940mm x 330mm).

*Model 3: Number of Cells*
The cells for the Model 3 are 21mm in diameter. Let's assume they get packed in a manner similar to the 100D battery modules. So it would have rows that are 20.5mm apart, with 2mm gaps between cells in the same row. Then, a single module could hold (330mm/20.5mm=) 16 rows of (940mm/23mm=) 40 cells. That gives (16x40=) 640 cells per module, and (640x8=) 5120 cells for the whole battery pack.

*Model 3: Energy Stored in Cells*
How much energy do the Model S's 18650 cells hold? If a Model S's 100kWh pack has 8256 cells, then I guess each 18650 cell can hold about (100,000Wh/8256=) 12.1 watt-hours. As a lower bound, if we assume each of the Model 3's 5120 cells can also hold only 12.1 watt-hours, that gives a pack size of 62kWh.

But, we know that the new 2170 cells can hold more energy than the 18650 cells. So, how much energy can the 2170 cell hold compared to the 18650? The 2170 has about 46% more volume than the 18650 (24,245 mm³ vs 16,575 mm³). Assuming it could hold 46% more energy, that would give us a 90.5kWh pack. So I think it will be quite reasonable to *expect an 85kWh pack - maybe even a 90kWh pack - to be offered as the top option for the Model 3*.


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## Daliman (Apr 20, 2016)

Holly callculating Batman!


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## AEDennis (Apr 10, 2016)

Funny... I saw the title of the thread and guessed 85 kWh...

And then read your calculations...


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## BigBri (Jul 16, 2016)

Seems like the right idea to me. Considering the 100KWH pack is their newest (we can speculate that the M3 pack will have more in common with it then an older Model S pack) then 90 makes sense given the 100KWH has a bit over 100kwh of capacity rather then the older packs that had a bit under the advertised capacity.


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## TrevP (Oct 20, 2015)

Thanks for doing this. I didn't really do any math but figured the pack is 85-90% the size of a Model S and given the new cells are indeed larger I figured there'd be less of them but the volume makes up for the pack size loss so I always figured 85kWh would be the upper capacity. 

I have a feeling the base pack will be 55kWh and a mid pack coming in at 70kWh giving their cars a 15kWh spread between options. If Tesla indeed has their costs in check then we could see just 2 offerings: 70 and 85kWh physical packs with the base being software limited to 55kWh with a OTA unlock possible.


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## MichelT3 (Nov 16, 2016)

I'm glad you both reach the same conclusions. This underlines the probability that something like this will be the outcome.

If Tesla has the costs in check that would also mean that the costs for extra battery size will be moderate, I think. Especially since range is such a big factor in BEV acceptance.
(Together with fast charging ability.)
A happy prospect!


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## Mike (Apr 4, 2016)

garsh said:


> Given all of the recent talk about Model 3 battery pack capacities that erupted after Elon's tweet:
> 
> __ https://twitter.com/i/web/status/829002643947167744I decided to attempt an actual calculation of the largest possible battery pack that will fit into a Model 3. So... LOTS of caveats. Since we have no official dimensions of any kind, I'm making a lot of assumptions and educated guesses. So whenever you see me provide a size for something related to the Model 3, it is a guess - an approximation.
> 
> ...


Nice work. Thanks.


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## AEDennis (Apr 10, 2016)

MichelT3 said:


> I'm glad you both reach the same conclusions. This underlines the probability that something like this will be the outcome.
> 
> If Tesla has the costs in check that would also mean that the costs for extra battery size will be moderate, I think. Especially since range is such a big factor in BEV acceptance.
> (Together with fast charging ability.)
> A happy prospect!


As an almost 5 year EV driver (23-February), battery size to give 150 miles and access to rapid charging in some the winning combo... doubling the pack size is the sweet spot to knock down 95% of the naysayers...

As I've been known to say, I stop on long range EV drives because I have to... and the car still has enough charge/range... and that's on an 85kWh Model S.


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## Gary Moore (Apr 10, 2016)

By SWAG (aka Kentucky windage), I was thinking the desirability of having an acceptable Ludicrous package for Model 3 would prompt the engineers to be asked: Can we safely stack at least 85kwh in there? From a marketing perspective, if the Model S buyer is paying the bigger bucks, you sanely don't want him greatly upstaged by someone buying a Model 3. I realize we're talking the real Elon here, but as the Puzo's Godfather was wont to say, "It's strictly business."

Thanks for all the estimation effort and presentation.


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## bluesolarflare (Apr 8, 2016)

So if margins allow we are possibly looking at:

Software Locked 55 unlocked to 70
High capacity battery being 85?


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## Mike (Apr 4, 2016)

Gary Moore said:


> ...you sanely don't want him greatly upstaged by someone buying a Model 3. I realize we're talking the real Elon here, but as the Puzo's Godfather was wont to say, "It's strictly business."


Something I've been bringing to various online conversations: that moment when resale values of current Model S' take a hit because the next gen architecture of Model 3 is so much improved. My first home PC (386/20) suffered the same fate.....

The real cash for Tesla will be the millions of Model 3's, like Henry Fords Model T......

Great line from a great movie by the way


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## Twiglett (Feb 8, 2017)

Mike said:


> Something I've been bringing to various online conversations: that moment when resale values of current Model S' take a hit because the next gen architecture of Model 3 is so much improved. My first home PC (386/20) suffered the same fate.....
> 
> The real cash for Tesla will be the millions of Model 3's, like Henry Fords Model T......
> 
> Great line from a great movie by the way


I don't think they will take too much of a hit - they will very likely drop, but they're still a bigger car in a different class.
Also much more likely to have free unlimited supercharging.


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## Mike (Apr 4, 2016)

EV4Life said:


> I don't think they will take too much of a hit - they will very likely drop, but they're still a bigger car in a different class.
> Also much more likely to have free unlimited supercharging.


I admit I'm no subject matter expert in economics and the economics of the automotive sector.

I'm too close to this, emotionally, so I can only go by my gut instinct (which is often not a good way to stay solvent), but......

....I can't help but wonder what Elon must be factoring into all the early marketing decisions of the Model 3 without hollowing out the Model S. There has to be a corporate recognition that if the Model 3 is artificially held back to maintain the Model S' perceived value, the company may ultimately take a bigger hit with the loss of some potential Model 3 sales.


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## Rick59 (Jul 20, 2016)

(25,000 S and X times Profit margin A) vs (500,000 3s times Profit margin B.)
If you assume A=$25,000 and B=$5,000, it's $625 million vs $2.5 billion.
Whatever numbers you pick, I think the answer is always the same: Model 3 is the driving force.


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## AEDennis (Apr 10, 2016)

Mike said:


> I admit I'm no subject matter expert in economics and the economics of the automotive sector.
> 
> I'm too close to this, emotionally, so I can only go by my gut instinct (which is often not a good way to stay solvent), but......
> 
> ....I can't help but wonder what Elon must be factoring into all the early marketing decisions of the Model 3 without hollowing out the Model S. There has to be a corporate recognition that if the Model 3 is artificially held back to maintain the Model S' perceived value, the company may ultimately take a bigger hit with the loss of some potential Model 3 sales.


Considering that Tesla does not do any marketing... I don't think you have to worry about this.

The Model S and Model 3 are going after different markets once the 3 is out. I doubt that the 60kWh-75kWh Model S will survive... which means starting prices for Model S will go up from their current levels as the top end Model 3 will fill in that spot.

Just a thought.


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## MichelT3 (Nov 16, 2016)

I don't really understand the worrying. Every carmaker has price-overlapping models. On purpose, because different models have different characteristics, applying to different customers. By having overlapping prices it's easier to satisfy different demands.

It's just a problem from our perspective, because we are totally Model 3 minded.

I can imagine someone saying: "I want a big Tesla, but without a huge range and the most advanced technical specifications. Why care that for the same price I can get a smaller car which has frills? I want a BIG Tesla."

I expect the Model Y to overlap prices of both 3 and S, maybe even X. Just as X overlaps S.


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## Mike (Apr 4, 2016)

AEDennis said:


> Considering that Tesla does not do any marketing... I don't think you have to worry about this.


I'm not a salesman, but my father spent 42 years in sales and marketing and he finds the whole Tesla marketing (his term) model brilliant.

I agree with you that the classical, Madison-Avenue-sells-ICE-to-the-crowd model of marketing is not being employed here.

IMHO, everything that Elon does, information flow wise for the Model 3, is marketing. Everything.


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## garsh (Apr 4, 2016)

The difference in volume between the old & new cells is actually 1.46. I've updated the last calculation of possible pack size. The conclusion is still the same, but with 85kWh looking even more likely than 90kWh.


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## MichelT3 (Nov 16, 2016)

Mike said:


> I'm not a salesman, but my father spent 42 years in sales and marketing and he finds the whole Tesla marketing (his term) model brilliant.
> 
> I agree with you that the classical, Madison-Avenue-sells-ICE-to-the-crowd model of marketing is not being employed here.
> 
> IMHO, everything that Elon does, information flow wise for the Model 3, is marketing. Everything.


By calling it marketing, it sounds to me like it's done with the purpose to sell.
While I'm convinced that the ulterior motive is not to sell and make money, but to spread EV's and renewable energy to better the world. That you can only do that if the new products are better than the fossil ones. And that is what people realise and what makes Tesla so attractive. The philosophy behind the make and its products.


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## Rick59 (Jul 20, 2016)

MichelT3 said:


> By calling it marketing, it sounds to me like it's done with the purpose to sell.
> While I'm convinced that the ulterior motive is not to sell and make money, but to spread EV's and renewable energy to better the world. That you can only do that if the new products are better than the fossil ones. And that is what people realise and what makes Tesla so attractive. The philosophy behind the make and its products.


Marketing is brand promotion, advertising is selling.


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## MichelT3 (Nov 16, 2016)

No, selling is selling... or?
The difference is in the ulterior motive. Selling as a goal, or selling as a means.


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## Mike (Apr 4, 2016)

MichelT3 said:


> By calling it marketing, it sounds to me like it's done with the purpose to sell.
> While I'm convinced that the ulterior motive is not to sell and make money, but to spread EV's and renewable energy to better the world. That you can only do that if the new products are better than the fossil ones. And that is what people realise and what makes Tesla so attractive. The philosophy behind the make and its products.


At the end of the day, I think we agree with Elon and his worldview move to electric propulsion.

That, in the context of Tesla (Motors), is what is the final goal is.

Elon is creating a product that must be irresistible to skeptics like my dad.

My father is coming around and that is no small feat, thus his respect for the marketing techniques being used.

The soft sell. Word of mouth. Snippets of information. Even that talk of a 2.0 second 0-60 thru unofficial channels....all building up customer demand, etc.

I 100% agree, that if the actual (new) ev product is not better than the fossil ones, it will fail.


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## Red Sage (Dec 4, 2016)

Gary Moore said:


> By SWAG (aka Kentucky windage), I was thinking the desirability of having an acceptable Ludicrous package for Model 3 would prompt the engineers to be asked: Can we safely stack at least 85kwh in there? From a marketing perspective, if the Model S buyer is paying the bigger bucks, you sanely don't want him greatly upstaged by someone buying a Model 3. I realize we're talking the real Elon here, but as the Puzo's Godfather was wont to say, "It's strictly business."


I offer again as evidence, the BMW M3 blows the doors off of every version of the BMW 7-Series. The 3-Series has been the best selling premium passenger car worldwide for decades. The Lexus IS has routinely sold horribly in comparison to the 3-Series. And the IS was woefully gimped compared to the LS for most of its existence. I think that the BMW strategy works a bit better than the Lexus one.


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## Topher (May 11, 2016)

bluesolarflare said:


> Software Locked 55 unlocked to 70


Tesla has already said that it will have less than 60 _actual_ kWh. No software unlocking to 70.



EV4Life said:


> Also much more likely to have free unlimited supercharging.


Unlimited free supercharging is gone, don't expect it will ever return. It disallows all sorts of things like vehicle-to-grid and commercial fleets (not to mention being a rent-seeking economic problem).



garsh said:


> The conclusion is still the same, but with 85kWh looking even more likely than 90kWh.


I think we can expect _some_ increase in capacity going from old 18650 to new 2170. 90 might be reasonable (95 seems unlikely only in that Elon was so emphatic that 100 was not (yet) possible).

Thank you kindly.


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## PRSIST (Apr 10, 2016)

Someone posted that they thought Tesla would start at a battery pack of 55 and then do 15 step increments, (55,70,85) I'm having difficulty remembering why everybody thinks the Model 3 will have a base pack of 55? Why not starting at what Tesla already has, a 60...Then a 75 and then a 90?

Whatever Tesla decides to do, I just wish they would hurry up and kick out some possible costs associated with the options. Not everybody has a ton of money sitting around...lots of us have to save up and time is running out.


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## Badback (Apr 7, 2016)

PRSIST said:


> Someone posted that they thought Tesla would start at a battery pack of 55 and then do 15 step increments, (55,70,85) I'm having difficulty remembering why everybody thinks the Model 3 will have a base pack of 55? Why not starting at what Tesla already has, a 60...Then a 75 and then a 90?
> 
> Whatever Tesla decides to do, I just wish they would hurry up and kick out some possible costs associated with the options. Not everybody has a ton of money sitting around...lots of us have to save up and time is running out.


Because Elon tweeted that the base battery pack on the ≡ will be less than 60kWh.


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## KennethK (Oct 13, 2016)

PRSIST said:


> Someone posted that they thought Tesla would start at a battery pack of 55 and then do 15 step increments, (55,70,85) I'm having difficulty remembering why everybody thinks the Model 3 will have a base pack of 55? Why not starting at what Tesla already has, a 60...Then a 75 and then a 90?
> 
> Whatever Tesla decides to do, I just wish they would hurry up and kick out some possible costs associated with the options. Not everybody has a ton of money sitting around...lots of us have to save up and time is running out.


Also, the packs on model 3 are all redesigned from those on X and S. So a 60kWh pack on a S does not even have the same dimensions that can be accommodated on a 3. Also the individual batteries are a different size 18x65 vs 21x70.


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## Mad Hungarian (May 20, 2016)

Red Sage said:


> I offer again as evidence, the BMW M3 blows the doors off of every version of the BMW 7-Series. The 3-Series has been the best selling premium passenger car worldwide for decades. The Lexus IS has routinely sold horribly in comparison to the 3-Series. And the IS was woefully gimped compared to the LS for most of its existence. I think that the BMW strategy works a bit better than the Lexus one.


I bring this exact same point up every time I hear the "they can't upstage the S" argument.
Couldn't agree more.


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## garsh (Apr 4, 2016)

Badback said:


> Because Elon tweeted that the base battery pack on the ≡ will be less than 60kWh.


It was Jeff Evanson, Tesla's VP of Investor Relations, who said that the pack would be less than 60kWh.
Ref: Tesla confirms base Model 3 will have less than 60 kWh battery pack option


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## Red Sage (Dec 4, 2016)

garsh said:


> It was Jeff Evanson, Tesla's VP of Investor Relations, who said that the pack would be less than 60kWh.
> Ref: Tesla confirms base Model 3 will have less than 60 kWh battery pack option


Yup. Remember the Bad Ole Days when so many insisted the Tesla Generation III vehicle would have a 48 kWh or lower capacity battery pack?


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## Badback (Apr 7, 2016)

garsh said:


> It was Jeff Evanson, Tesla's VP of Investor Relations, who said that the pack would be less than 60kWh.
> Ref: Tesla confirms base Model 3 will have less than 60 kWh battery pack option


My bad.


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## garsh (Apr 4, 2016)

So Randy Carlson has posted another article on Seeking Alpha:
Tesla: Model 3 Update - What To Look For

In this article, he wonders if Tesla can get away with arranging the cells horizontally instead of vertically. In particular, he wonders if chemistry improvements might allow Tesla to get away with having only a single layer of horizontal cells in the packs. Given my calculations of module size above, we could then fit at most (940mm/70mm=) 13 by (330mm/21mm=) 15, or 195 cells/module (Randy estimates 220 cells/module).

This gives (195*8=) 1560 cells for the whole vehicle. In order to get even a 70kWh pack out of this arrangement (since we've heard rumors that this pack size does exist), then each cell must be capable of holding (70000/1560=) 44.9 watt-hours. This would be a HUGE jump from the 12.1 watt-hours contained in current 18650 cells.

Even a double-layer of cells would require 22.5 watt-hours to be contained within each cell. That _would_ allow the battery pack to be 28.5mm thinner (assuming a 0.5mm overlap in rows), which is something, but not a huge win. And this is at least within striking distance of the 18 watt-hours per cell that I calculated above, which assumes that the cell chemistry hasn't changed from the 18650 so that only the volume difference is important. But that would also dash my dreams of owning a P85D Model 3. We shall see.


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## Michael Russo (Oct 15, 2016)

garsh said:


> So Randy Carlson has posted another article on Seeking Alpha:
> Tesla: Model 3 Update - What To Look For
> (...) We shall see.


@garsh , thank you. Had posted the same article in the Mixed Bag of Analysts Opinion yet without the deeply grounded analysis you provide here... unfortunately lacking that knowledge... 
Also, I like how you end your post... Exactly what I wrote on the other debate re wheels sizes... Time will tell


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## Uricasha (Feb 19, 2017)

garsh said:


> So Randy Carlson has posted another article on Seeking Alpha:
> Tesla: Model 3 Update - What To Look For


I steer clear from most of the Seeking Alpha articles. They were interesting to read until one day I realized that one guy wrote two opposing articles in the same day.... imo, a lot of it is clickbait.

Your write-up was intriguing though


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## garsh (Apr 4, 2016)

Matthew Morgan said:


> I've always steer clear from most of the Seeking Alpha articles. They were interesting to read until one day I realized that one guy wrote two opposing articles in the same day.... imo, a lot of it is clickbait.
> 
> Your write-up was intriguing though


Randy Carlson's articles are all worthy reading. But so far, he's the only one posting there who considers technology and long-term vision. Everybody else thinks that Tesla should just be trying their darnedest to make a profit ASAP, and they don't even consider the type of technological (and societal) changes that Musk is trying to bring about.


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## TrevP (Oct 20, 2015)

garsh said:


> So Randy Carlson has posted another article on Seeking Alpha:
> Tesla: Model 3 Update - What To Look For
> 
> In this article, he wonders if Tesla can get away with arranging the cells horizontally instead of vertically. In particular, he wonders if chemistry improvements might allow Tesla to get away with having only a single layer of horizontal cells in the packs. Given my calculations of module size above, we could then fit at most (940mm/70mm=) 13 by (330mm/21mm=) 15, or 195 cells/module (Randy estimates 220 cells/module).
> ...


The only problem I have with his thoughts is that Tesla did show the Model 3 CAD model at the reveal event that fairly clearly shows the cells are indeed vertical:










Also, JB stated the new cooling and cell arrangement in the new 100kWh packs are derivatives of the Model 3 system. It's also my belief that Tesla won't be reinventing the wheel here with module layouts. The main cost savings come from a new optimal cell size, chemistry and massive economies of scale.


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## garsh (Apr 4, 2016)

Holy crap, @TrevP! I didn't realize that you could blow up that still image large enough to make out more than modules! It does kind of look like it's showing individual cells.

But I don't think it really is. Recall that I calculated that Tesla can fit 16 rows of 40 cells into each module. From this picture, it looks like each module only contains 8 rows of very, very large cells. So, next best guess is that each of the round bumps at the ends of of the modules is actually a bend in the cooling loop, which spans two rows of cells:









So I agree, it certainly does look like the cells are vertical, and I think this provides further proof that the modules likely contain 16 rows of cells. That makes me feel a bit more confident in my calculations. Furthermore, it appears that 4 of the 16 rows have fewer than the maximum number of cells that would fit within the module's rectangular area. This also occurs in the Model S modules, and provides more reason to believe that a 90kWh battery is not very likely.

Also from the blown-up picture, there appear to be 3 rows of 5 "holes" running down each battery module. There doesn't appear to be anything equivalent in the Model S battery pack, so I'm not sure what to make of these.


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## Badback (Apr 7, 2016)

garsh said:


> So Randy Carlson has posted another article on Seeking Alpha:
> Tesla: Model 3 Update - What To Look For
> 
> In this article, he wonders if Tesla can get away with arranging the cells horizontally instead of vertically. In particular, he wonders if chemistry improvements might allow Tesla to get away with having only a single layer of horizontal cells in the packs. Given my calculations of module size above, we could then fit at most (940mm/70mm=) 13 by (330mm/21mm=) 15, or 195 cells/module (Randy estimates 220 cells/module).
> ...


What about the thickness of the temperature management coils?


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