-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Investor Engineering Discussions
- Thread starter MC3OZ
- Start date
Yeah...
I think he's conflating monocoque.
Cybertruck was never going to have stressed side skin in the middle. So the 'delayed' line of thought makes no sense.
Here's the exoskeleton:
Structure on the outside, including rear load path.
It's a unibody frame plain and simple. They are simple A, B and C pillars, just like every other pickup truck on this earth has - with the exception of a unibody structure as opposed to the typical body on frame design. Here's a picture of an F150 aluminum body that sits on top of the ladder frame for example. Same A, B and C pillars:
Here's a unibody frame picture from a Honda RIdgeline:
Attachments
JRP3
Hyperactive Member
But how is that functionally different than a unibody? And is it actually an exoskeleton?
Body-on-Frame vs. Unibody vs. Monocoque: What’s the Difference?
A look at the history of vehicle structural design considering body on frame, unibody, monocoque, space frame, skateboard chassis, and other techniques.
Yeah, I'd read those sites too.But how is that functionally different than a unibody? And is it actually an exoskeleton?
Body-on-Frame vs. Unibody vs. Monocoque: What’s the Difference?
A look at the history of vehicle structural design considering body on frame, unibody, monocoque, space frame, skateboard chassis, and other techniques.www.motortrend.com
It's different than every other truck that has a ladder frame.
"This is the fundamental design change where we move the mass to the outside. We created an exoskeleton. So normally, the way that a truck is designed you have a body on frame. You have a bed on frame. And the body and the bed don't do anything useful. They're carried like cargo like a sack of potatoes."
All of the Cybertruck's material (other than firewall and rear wall) is pushed to the outside. Similar to a unibody, but it's different in that the outer layer is durable.
"It allows you to do things that you can't do with a body on frame. So we're able to make the skin out of thick ultra hard stainless steel. "
The exoskeleton enables the stainless skin. A shell on the exoskeleton (hermit crab). Or, if you prefer, the exoskeleton is three layers thick.
JRP3
Hyperactive Member
But not much different than a unibody. Is there any reason a thicker skin couldn't also be attached to any conventional unibody?
I agree that unibody and exoskeleton have overlap.
The issue with using the 3mm stainless over a conventional body is that, large planar surfaces (especially creased ones) don't like to flex. Unless the substructure is equally rigid, the body deflects relative to the skin. That results in: shearing off of attachment points, flexure (oil can or creasing) of the skin, or that the skin is the load member.
Of course, the attachment points could be compliant like truck body to frame mounts, but that is bad from a dimensional control and/ or fatigue point of view.
JRP3
Hyperactive Member
Sure you have to match material characteristics appropriately. Maybe the Cyber should be called uniskeleton, or exobody?
Yah, but you asked about "conventional unibody"
Stainless: definitely outer shell aka exoskeleton with questionable load responsibility.
Is Cybertruck a turtle?
JRP3
Hyperactive Member
I was thinking in terms of design and not material. "Conventional unibody" can be made of steel, aluminum, or a combination of both, or even composite.Yah, but you asked about "conventional unibody"
Buckminster
Well-Known Member
Doggydogworld
Active Member
Drew’s comment on earnings call: Ready to start production of CYBERTRUCK cells, with 10% greater energy density than existing 4680. This meets their energy requirements for the cybertruck, anodes with silicon, and in-house cathode, will be coming another day.
GSp
GSp
That's not encouraging to me. A 10% energy density increase over the 1st gen 4680 packs at 244kwh/kg means it'll rise up to ~270wh/kg - roughly equivalent to the current 2170 packs. Even assuming a larger structural battery pack for the CT, I don't see a path toward a 500 mile range unless Tesla basically does the same thing as GM/RAM and goes with a 200+kw pack size. That would really increase the weight of the CT though. Anything is possible, but I've seen quite a few recent rumors that the initial CT launch is only going to include a 350 mile range dual motor CT - with the tri-motor model coming at a later time, perhaps 2025/2026 when the battery pack innovations promised at battery day actually come to fruition. Just my two cents of course.
bkp_duke
Well-Known Member
Disagree. Tesla clearly stated on the call that 10% was without other things known to increase energy density by a significant margin, like silicon anode doping, etc.
Optimization-wise, they are still VERY VERY EARLY in the curve on the 4680s. This is expected because DBE is such a massive change (bigger than anything else done AT SCALE in the battery world in 20 years) that you don't just add all these additional enhancement items from the get go. You work with basic chemistry design to perfect the process, then you add things in, one variable at a time.
I haven't put my chemistry degree to use in 20+ years, but this one I am very confident in that they are taking the correct approach.
Doggydogworld
Active Member
244 and 270 Wh/kg are cell densities. Pack densities are much lower.
Similar threads
- Marketplace listing
