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2022 Model Y 4680 Structural Pack is "Amazing", Says Munro & Associates

Munro & Associates has just released an analysis of the structural pack for Tesla's 4680 battery cells, having just received a 2022 Model Y SR from Giga Texas.

In their analysis, Cory Steuben (President of Munro & Associates) and Julian Aytes (lead engineer) found that the car's front seats are directly mounted onto the structural pack itself, making the structural pack essentially the vehicle's floor itself.

"It's absolutely mind-blowing to be standing under a vehicle on a hoist and have absolutely nothing for the floor structure. To truly understand how amazing it is to see a vehicle with no floor and the seats mounted to the top of the structure on the pack, you have to go back more than years, but decades."

Screen Shot 2022-07-05 at 8.44.44 PM.png

(Source: Munro & Associates)

The structural pack, including the seats and other components mounted to it, weighs 1,198 pounds, which is "incredible because in a couple of the other EVs we have, the batteries will weigh twice that. Just the batteries. No seat, no carpet, no trim."

According to Elon Musk, the structural pack is "the right overall architecture from a physics standpoint, but still far from optimized," which seems to be a modest take on the speed of Tesla's design improvements.


Despite minor manufacturing issues found by the team, the Giga Press casting machines, noted as the world's largest high-pressure die casting machines, have done an amazing job at astronomically decreasing both parts and complexity for the structure of the chassis itself.

"At Munro & Associates, we've seen the development of the automotive industry for the past 30 to 40 years. I've come from a background of benchmarking vehicles where you'd have hundreds of stamped parts where this front giga casting is, and hundreds of parts in the back. The level of refinement and integration is incredible. Tesla is not waiting to integrate the casting for multiple mounting features."

Overall, these improvements have come from decades of constant work and continuous improvement on Tesla's end, and it is clear to see why Tesla is so ahead of many other manufacturers in terms of vehicle and battery structure.

Steuben mentions that the next goal for their analysis is to remove the battery cover and be able to know how Tesla is securing the 4680 cells themselves and take a look inside the battery pack itself.

The full breakdown and analysis is linked below.

 
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Okay, didn't know that. Thanks for the info!

Now I shudder at the thought of my battery pack ever needing to be replaced. The disassembly and reassembly looks like a nightmare. No doubt there would be missing bolts everywhere or some line not connected properly.
Do you shudder at the thought of replacing an engine in an ICE car? They involve far more work and complexity than a battery pack.
 
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Krash

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Do you shudder at the thought of replacing an engine in an ICE car? They involve far more work and complexity than a battery pack.
To be fair, it is way cheaper. In an old car you’d buy a crate engine, borrow a hoist, put it in. Now there are more things to disconnect and move but the same idea.

I’d have to call someone like Jason Hughes to configure my car for a new S/X battery. I can’t imagine dropping a new Y battery.
 
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828 cells vs 4416 cells =5.3x more cells in the 2170 pack and the 4680 cells have roughly 5.5x the volume.

If the energy density were the same we’d have have roughly the same, maybe slightly more energy in the 4680 pack. A previous video from the Limiting Factor estimated the energy density to be about 15% higher with the 4680 cells. That puts the 4680 pack somewhat higher total capacity than the old 2170. Still waiting to see an actual analysis of the battery cells themselves.
 
The next Munro video on the 4680 pack is out:


Biggest news is that it is 9 cells in parallel. And they say 828 cells.

Fascinating stuff. Seems to imply that either the 4680 cells are only about 85 Wh each (way under the ~100 Wh design) or some of the cells are dummies... I notice he initially said 828 cells, but when talking about taking "all" the cells out he says 600.... likely a slip of the tongue, but interesting.
 
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AlanSubie4Life

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Oct 22, 2018
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Biggest news is that it is 9 cells in parallel. And they say 828 cells.
Yes, which we had kind of deduced here already, with your input on bandoliers and the remaining possibilities and how things have to work out to be integer multiples of various factors.

This is 92s9p (each module is 23s9p) in terms of real/dummy cells. (Some potentially could be placeholders.)

The bandoliers are made of 69 cells, one row of 35, one row of 34. Groups of three at a time of these are tapped to make 23 groups of 3, and then tied across the three bandoliers to make 23 groups of 9 (3*3), a brick, I guess is the parlance. Overall pack is of course the four modules in series to make 92x9.

There are three cooling snakes per module, one per bandolier, going between the two rows of 35/34. (Unlike some had earlier suggested here.) The tubes are pretty substantial; you can see one ripped open in the video I think. [EDIT: Actually a little hard to tell whether there is also cooling between bandoliers in the video; perhaps there is some evidence of one. The spacing wasn't noticeably closer between adjacent bandoliers, which implies maybe there is a spacer there, which would make sense to have be cooling. I'm not sure about this at all though - it was just easy to see the connections to the middle of the bandoliers but less clear on the other intervening space. It does kind of look like a coolant connection exists there on the lower side as well, see attached.]

This is a lower voltage pack (386V max) than the previous Model Y pack (96s46p 2170L, ~403V max, nominally 350V). That prior pack is ~82kWh (as tested by EPA that is the maximum seen, possibly only for Model 3; haven't checked the Model Y docs, but it's the same pack).

Not sure why at 9:15 they talked about current collectors increasing/decreasing in size. Same current throughout the module of course. You can see the main current path (which of course follows generally shortest path but cell have inherent voltage difference so there will be flow across the bricks) from where the collectors are thickest. Each collector just makes 9 cathode and 9 anode connections, with appropriate voltage sensing at each of these nodes (of which there are 24 for 23 bricks). You can see all of these welds for each of the collectors (18 welds per).

This should be an ~82kWh pack if fully populated and fully unlocked, but existing Model Y 4680 vehicles have tested at 70kWh.

Depopulation options would have to be in a single bandolier per module presumably (every third cell in a bandolier on average would be a dummy), but no evidence of that; all assembly looks exactly like it would if these were all real cells as far as I can tell. It would make sense to do this on the outside bandolier for CG reasons and marginal safety improvement, but Munro had removed four cells in a row on the outside and didn't mention anything...so....


The weight being comparable between 2170L and 4680 doesn't really point to depopulation, but of course the steel cans are pretty heavy overall so who knows how it all works out. Guess we'll find out at some point.

Screen Shot 2022-08-03 at 2.58.10 PM.png
IMG_2652.PNG
 
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Fascinating stuff. Seems to imply that either the 4680 cells are only about 85 Wh each (way under the ~100 Wh design) or some of the cells are dummies... I notice he initially said 828 cells, but when talking about taking "all" the cells out he says 600.... likely a slip of the tongue, but interesting.
Currently, the closest we have to an analysis of a 4680 battery is from Jordan Giesige on his Limiting Factor youtube channel where he tore down a 6 month old 4680 battery and made some estimates of its specs. He came up with something on the order of 98 wh/cell. He also noted that there was room for improvement based on the battery he analyzed. He is waiting to get a full production 4680 battery from Munro & Associates to report on.

92 wh/cell would put a 828 cell battery pack at 81 kWh Or about 15% above the current 70 kWh pack. Possibilities I can think of:
  • Dummy cells in the battery pack to keep the actual capacity at 70 kWh - this would make sense from a production standpoint as they could maximize the number of packs & minimize the cost for a given number of cells produced. Weight analysis doesn’t support this, though. A 70 kWh battery pack would be about 714 cells meaning 114 of them were dummies. That should be enough weight to notice but maybe not?
  • lower actual capacity of the cells. 70 kWh/828 = 85 wh/cell.
  • The pack is actually an 81 kWh pack with part of the capacity locked out. This would actually fit some reports that have surfaced of people noting regenerative braking being available despite 100% charge and being able to fast charge 0-90% in less than an hour. This would also potentially allow Tesla to sell a ‘range upgrade’ that unlocks the increased range of the battery pack.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
13,366
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San Diego
A 70 kWh battery pack would be about 714 cells meaning 114 of them were dummies. That should be enough weight to notice but maybe not?

The only option is 92 dummies, 736 real cells. This would be done with 92s8p, with 23 dummies per module, presumably taken from just one bandolier per module (though other arrangements of depop of course are possible, it would be odd, because then there would be more than two types of bandolier population patterns, terrible for production). If that were the case the per-cell capacity would be at least 95Wh.

I would guess the last option right now. Fully populated, 80+ kWh pack.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
13,366
17,012
San Diego
There are three cooling snakes per module, one per bandolier, going between the two rows of 35/34. (Unlike some had earlier suggested here.) The tubes are pretty substantial; you can see one ripped open in the video I think. [EDIT: Actually a little hard to tell whether there is also cooling between bandoliers in the video; perhaps there is some evidence of one. The spacing wasn't noticeably closer between adjacent bandoliers, which implies maybe there is a spacer there, which would make sense to have be cooling. I'm not sure about this at all though - it was just easy to see the connections to the middle of the bandoliers but less clear on the other intervening space. It does kind of look like a coolant connection exists there on the lower side as well, see attached.]
The exit on the lower side is the exit for the coolant presumably. Prior pictures of the pack and the new Munro video kind of show that.

Anyway, just three cooling separators per module, one per bandolier.

And of course the new video confirms the 69 cells per bandolier but that was obvious from their prior video.

No word about any dummy cells in the video, and they had completely disassembled a module, so I assume that means it is fully populated.

I’d guess it is an 80kWh pack or so (so heavily locked out since only 70kWh is usable until the car shuts down, per the EPA test).
 
Just a random addition to the thread (I searched first but didn't see this mentioned, but I haven't read every post in this thread, so I apologize if this has already been mentioned).

If you want your very own 4680 cell, Munro is selling them for only $800 / each.

Gotta hand it to them. Buy a Model Y for ~$75K, sell 828 cells for $800 each and gross $662K. Granted, the tear down looks like it was a giant pain, so it's not all profit, but not too shabby either.

I'm not affiliated, but here's the link if you want to take a look: 4680 Battery Cell from Austin Built Model Y (Please read description.).
 
Jordan Giesige posted another video on his Limiting Factor you tube channel yesterday going over a lot of the engineering and design considerations that went in to the 4680 cells. It's very refreshing to see someone go into depth on all the considerations and provide thoughtful commentary instead of just doing soundbites or knee-jerk reactions.

Something else that comes out in the video is how potentially significant Tesla's battery innovations are for EVs in general and ultimately the environment. It's part of the reason I still support Tesla - I disagree with a lot of Elon's antics and Tesla's cars are far from perfect but they've done more to move the industry forward in the last 10 years than Ford, GM and Chrysler have done in the last 50.
 
Jordan Giesige posted another video on his Limiting Factor you tube channel yesterday going over a lot of the engineering and design considerations that went in to the 4680 cells. It's very refreshing to see someone go into depth on all the considerations and provide thoughtful commentary instead of just doing soundbites or knee-jerk reactions.

Something else that comes out in the video is how potentially significant Tesla's battery innovations are for EVs in general and ultimately the environment. It's part of the reason I still support Tesla - I disagree with a lot of Elon's antics and Tesla's cars are far from perfect but they've done more to move the industry forward in the last 10 years than Ford, GM and Chrysler have done in the last 50.
Can you imagine where we'd be if GM hadn't treated the EV1 as a complete joke? That's 25 of the last 50 years right there!
 
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Can you imagine where we'd be if GM hadn't treated the EV1 as a complete joke? That's 25 of the last 50 years right there!

GM had two different working EV prototypes in 1966 - a lead-acid "Electrovair" version of the Corvair, and a rolling-Hindenburgh-Van with a LOX/H2 electric fuel cell powering it. They've been walking away from things (some for good reason, some less so) for far more than 50 yeaars.
 
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Can you imagine where we'd be if GM hadn't treated the EV1 as a complete joke? That's 25 of the last 50 years right there!
See EV1 profile pic.

I can tell you with absolute authority that the EV1 made significant strides in mass reduction, aero, power electronics, new manufacturing techniques, etc over the state of the art. However, the battery technology did not exist at the time for significant range. The original EV1s had Pb acid packs and the gen 2 were NiMH. Without batteries, there was only so much that could be done to stretch range.

I started at GM as an engineer right when EV1 was phasing out and worked with many of the engineers who designed it. In the late 90's and early 00's there was no mass public desire for EVs. The EVs and hybrids at that time were made to satisfy Clinton-era CAFE (corporate average fuel economy) increases. Car companies exist to make money to pay wages and satisfy investors. In the early 2000's there was no business case to make EVs at scale. EVs and hybrids were marketed for economy (e.g. not sexy). The fact that the EV1 was made at all and leased to real customers was astonishing at the time. In 1998, EV1 was a spaceship from the future. I have driven 1000s of miles in EV1, and at the time, very few cars on the road turned heads like EV1.

The EV1 documentary definitely shaped the present day narrative of the EV1 from being revolutionary to being malicious corporate mismanagement. At the time, it was hard enough to make the case for hybrid vehicles (which is what I designed). Gas in the late 90s was $1/gal. GM and likely every other OEM has continued research and development of all these technologies but did make anything at scale because of business cases. The comment above is revisionist and out of touch with what was technically possible at the time 30 years ago and what the public would support (buy). We are just now seeing what it takes for an OEM to scale up EVs in terms of resources and investment.

This is how Tesla redefined the industry. Tesla also had the benefit of being treated as tech company in the 2010's and not a car company. It was (is?) totally fine for a tech company to run negative margins for years. Not so for an OEM. Also remember that the late 90s is when the tech bubble burst and public investors and VC money was drying up for new tech startups. I don't think Tesla would have survived at the time EV1 was developed and killed off.

Anyway, sorry for the EV1 tangent. Back to 4680 discussion.
 

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