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Discussion Starter · #1 · (Edited)
Here's a photo of one of the first applications of the new Tesla 4680 structural battery:

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For comparison, behind the cut away mock-up is a mock-up of the old 2170 cell design.

This is from the Berlin Gigafactory public tour. It looks like the battery box completely replaces the floor and is bolted into the cast and sheet metal body. Corrugated cooling channels appear to be placed between every other row of cells. Not shown are the buss bars and the bonding between the top cover/ floor and the top of the cells. There's a lot of DIY potential here, with the right vehicle, with the bolt-in design and structural member aspect of the battery box.
 

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Discussion Starter · #3 · (Edited)
I don't think you recognize the extra strength and energy density advantage of having the cells packed tightly, and bonded together. The cell's cylindrical steel housings do double duty as a honeycomb like structure. When this honeycomb is bonded to the top and bottom of the battery box, this forms a very strong and material efficient honeycomb box and beam structure. Honeycomb designs are in the structures of many aircraft, spacecraft, and race cars where stiff, strong, and lightweight parts are needed.

So, maybe you could park 2 or 3 tractors on this battery box!
 

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Discussion Starter · #9 · (Edited)
The battery likely handles its own structural weight, which a Tesla module does as well, but NFW does it add anything to the chassis for structural strength.
I guess we'll find out the first time somebody removes the battery box. I suspect a vehicle with this very strong and stiff honeycomb design battery box removed, will be a very weak and flexible structure indeed.
 

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Discussion Starter · #20 ·
The cars are easily totaled (which is good for salvage vultures like those of us here) because they are not designed for repair.
This is an unfortunate trend with virtually all modern vehicles. From a DIYEV builder's POV, it is better if good reusable parts from vehicles like this become more readily available on the secondary market. The more vehicles that are totaled because of rich people and others freaking out about off body seams and a few dents, the more parts that we need are on the market. In the case of Tesla, that's top notch electronics, drive units, battery modules, and now potentially this excellent structural battery box.

I think that the assumption is that the original owner will never need to have this done, and subsequent owners don't matter.
It's quite inconceivable to me that Tesla would not make it reasonably easy to replace the battery box. Enough people are going to brick their batteries, or otherwise destroy them during the warranty period, to make this necessary. Removal is probably 1 to 2 hours of removing interior parts, mounting bolts, disconnecting plugs(like you write) and running a cut-out wire through the perimeter seal.
 

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Discussion Starter · #21 ·
It's quite inconceivable to me that Tesla would not make it reasonably easy to replace the battery box. Enough people are going to brick their batteries, or otherwise destroy them during the warranty period, to make this necessary. Removal is probably 1 to 2 hours of removing interior parts, mounting bolts, disconnecting plugs(like you write) and running a cut-out wire through the perimeter seal.
Looking at the latest Monroe and Associates vid, it seems the battery pack removal is even easier than this:

I don't believe the uninformed and unimaginative among us realize just how revolutionary this structural battery pack design really is. As Musk has recently tweeted, other interesting applications of a structural pack are also possible. Any design ideas?
 

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Discussion Starter · #23 ·
Some revolutionary aspects of this removable floor/structural pack come to mind. On the assembly line, the workers can stand in the open floor space to attach the head liner and most of the interior parts. This is a much more ergonomic and efficient way of attaching these parts. It involves much less crawling around on hands and knees to finish the interior. I'm impressed with the sliding center console. When I first saw the seat/ protruding console/ battery pack assembly, I thought they would need to tip it up in the front to install the assembly. Instead, the console slides back on rails temporarily and the assemble goes straight up. Nice detail.

If the full strength and stiffness of the honeycomb like structural battery pack in torsion, laterally, and longitudinally is utilized, the rest of the vehicle's structure could potentially be made lighter. The vehicle's structure could be optimized for crash and roll over protection.

If the pack is built in a honeycomb like structure, as advertised, the top and bottom covers will be heavily bonded to the top and bottom ends of the 4680 cells. Solvents and/or heat may be required to remove the covers. Let's hope the cells aren't damaged in the process. Monroe wants to sell the cells to OEM clients and the public (if they can afford it) for what- $800? a piece!
 

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Discussion Starter · #25 ·
There will have to be some kind of electrically isolating structure between the ends of the cells and the covers. My designer mind envisions a plastic grid that also holds the conductors, and has pins to keep the cells separated. It would have to be as open as possible to allow the maximum of bonding contact between the cells and the covers with an epoxy and/or intumescent glue. Musk says in a tweet, as I recall, that the design for the battery box was still evolving.

What does our resident crotchety burned-out old engineer and forum takeover artist think the design will look like? Meh meh meh meh...
 

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Discussion Starter · #27 ·
If the pack is built in a honeycomb like structure, as advertised, the top and bottom covers will be heavily bonded to the top and bottom ends of the 4680 cells. Solvents and/or heat may be required to remove the covers. Let's hope the cells aren't damaged in the process. Monroe wants to sell the cells to OEM clients and the public (if they can afford it) for what- $800? a piece!
As predicted, the cells are heavily bonded to the top and bottom covers:

 

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Discussion Starter · #32 · (Edited)
Some revolutionary aspects of this removable floor/structural pack come to mind. On the assembly line, the workers can stand in the open floor space to attach the head liner and most of the interior parts. This is a much more ergonomic and efficient way of attaching these parts. It involves much less crawling around on hands and knees to finish the interior. I'm impressed with the sliding center console. When I first saw the seat/ protruding console/ battery pack assembly, I thought they would need to tip it up in the front to install the assembly. Instead, the console slides back on rails temporarily and the assemble goes straight up. Nice detail.

If the full strength and stiffness of the honeycomb like structural battery pack in torsion, laterally, and longitudinally is utilized, the rest of the vehicle's structure could potentially be made lighter. The vehicle's structure could be optimized for crash and roll over protection.

If the pack is built in a honeycomb like structure, as advertised, the top and bottom covers will be heavily bonded to the top and bottom ends of the 4680 cells. Solvents and/or heat may be required to remove the covers. Let's hope the cells aren't damaged in the process. Monroe wants to sell the cells to OEM clients and the public (if they can afford it) for what- $800? a piece!
Confirmation of these revolutionary design details are at least initially discussed in this video starting ~ 29:00

 

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Discussion Starter · #33 ·
Also in this video is a discussion about, for lack of a better term, flaky info on battery energy densities and vehicle ranges. Tesla's claims in this area seem to be all over the place and maybe based more on economics and politics, than actual battery capacity. There might be, as discussed in the video, better battery performance through improved chemistry than was previously revealed.

We'll soon find out. If it is the case, it augurs well for the Semi and other vehicles that from the start seemed to have inflated range figures.
 
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