All engineering topics (out of main)

[mongo]

Without squirming under the front of our Models S or X, can someone remind me of the extant radiator coils each model currently has? The follow-up question is: during an extreme atmospheric event like a silicic volcanic eruption - try to imagine the worst conceivable dust storm and you're getting reasonably close - could those coils become compromised enough to reduce their heat-shedding ability so that the cars cannot properly function?

Rim of Fire has enough Usual Volcanic Suspects and Tesla owners that a Vann diagram would demonstrate significant overlap. US residents can harken to the 1980 Mt. St. Helens eruption, whose ashfall absolutely clogged automobiles' air intake filters. Teslas do not have, obviously, that weak link but my question about coolant coils stands.

Placing that question's premise on its head, the extent to which radiator coolers can be affected by ashfall will indeed affect ICE vehicles before EVs....regardless, I think it pertinent to learn the answer and if it is potentially a problem, consider prophylactic responses.

One condensor on each side (behind automatic louvers), radiator in the middle. I don't think silica dust would overly accumulate, it would pass through the fins. (Unlike jet engines where it coats the blades) Supercharging is the worst case heating condition (and or interior AC), car will reduce charge rate if it overheats so even if there were blockage, you would still have functionality.

 

[bhtooefr]

Me too, in principle. The catch is however that to get a high charging rate, you need a large battery to not fry it while charging...

So you can charge a small battery quickly - I've seen charging as high as 133 A on my Prius's 3.5 Ah pack (I'd do that in kW/kWh, but my ScanGauge can't multiply gauges together, and the battery voltage and current are separate PIDs, so I just monitor amps - the pack is 207.2 V nominal, though), which is 38 C. Compare to the Model 3 at something like 3.5ish C peak.

The problem, of course, is that you need a cell design with lower internal resistance to pull that off. And, to do that, you end up with thicker components in the cell, and worse energy density (both volumetric and gravimetric)... which means you just threw away some of your capacity to get your power, meaning you need a bigger, heavier pack to get that capacity back, negating some of the gains from trading energy density for power density, and you very much get to a point where that strategy just isn't worth it... and on a BEV, that happens very quickly.

 

[mongo]

So you can charge a small battery quickly - I've seen charging as high as 133 A on my Prius's 3.5 Ah pack (I'd do that in kW/kWh, but my ScanGauge can't multiply gauges together, and the battery voltage and current are separate PIDs, so I just monitor amps - the pack is 207.2 V nominal, though), which is 38 C. Compare to the Model 3 at something like 3.5ish C peak.

133 A would charge the pack in 95 seconds. Are you sure those numbers are correct?
3.5 Ah x 207.2 V is only 0.7252 kWh.

Do you have the second gen Prius?
The post 2000 cars were 1.8kWh (6.5Ah 273.6V) , second gen 1.3 kWh (6.5Ah 201.6V) both with nickel metal hydride packs kept between 40 and 60%.
Toyota Prius - Wikipedia

6.5 Ah puts 133 at about 20 C, which still seems high for the chemistry.

 

[bhtooefr]

Fourth-gen with Li-ion pack.

Note that it can't sustain those charge (or discharge - a couple days ago I momentarily saw 153 A) rates for very long, but when it only operates between 20 and 80% SoC (and really wants to stay between 25 and 65%)...

 

[Silent Ludicrosy]

No. They have not. But it is obvious. That is the tech., that reduces costs radically. No paint shop, minimal body shop with no car specific tooling.

I was under the impression that die-cast unibody was the ultimate goal, not folded stainless steel. Diecast unibody could end being the cheapest option and still allow for curved aerodynamic shapes.
Tesla Files Patent Application For Die-Cast Unibody Machine | CleanTechnica

 

[gerebgraus]

I was under the impression that die-cast unibody was the ultimate goal, not folded stainless steel. Diecast unibody could end being the cheapest option and still allow for curved aerodynamic shapes.
Tesla Files Patent Application For Die-Cast Unibody Machine | CleanTechnica

My possibly wrong impression that Die-cast unibody cannot be done on stainless steel. So that technique would not eliminate either the paint shop or the specialized tooling. It would be a major advance of the current bodyshop only.
(I am way above my head on this, so I should stop speculating about that.) Anybody with actual expertize?

 

[Artful Dodger]

My possibly wrong impression that Die-cast unibody cannot be done on stainless steel. So that technique would not eliminate either the paint shop or the specialized tooling. It would be a major advance of the current bodyshop only.
(I am way above my head on this, so I should stop speculating about that.) Anybody with actual expertize?

An Engineering Professor at the University of North Carolina has been doing it for 10 years. The trick is in creating a metal foam with hollow spheres. See her videos on Youtube. I linked to one of them in my previous post.

 

[SOULPEDL]

Bonus: metal foam is ~1/3 the weight of cold rolled SS for the same strength panel, and has superior crush performance for safety features.

Whoa this is cool stuff! As the body, you'd be left with a swiss cheese finish.
So go me thinking, can you snap on covers? Then what about snap on curves for added drag efficiency + aesthetics?

And that Fly website looks rather handy for TSLA news, thanks! (forgot who)

 

[SunCatcher]

An Engineering Professor at the University of North Carolina has been doing it for 10 years. The trick is in creating a metal foam with hollow spheres. See her videos on Youtube. I linked to one of them in my previous post.

Epic advancement in engineering science involving steel/metal castings. If this could be used in the Cybertruck unibody casting, it would be an incredible leap forward in auto manufacturing. Imagine the steel frame itself as a crumple zone. Not to mention reducing the weight of the vehicle. Science just gets better and better. Can you imagine Elon not being aware of this? "TSLA to the moon Alice!"

Now, back to our regularly scheduled fear mongering... meh.

 

[Artful Dodger]

Whoa this is cool stuff! As the body, you'd be left with a swiss cheese finish.
So go me thinking, can you snap on covers? Then what about snap on curves for added drag efficiency + aesthetics?

Lol, keep reading. (you know that even swiss cheese has a solid outer layer?)

Agree on the aesthetics, and you can add crash protection and bullet proof as needed. SS handles the rustproof. Worth a few years R&D work to get all this, wot? I think this is how Tesla gets to 20M cars/year capacity. Turnin'em out like sausage links.

Oh, and BTW, the voids in the SS metal foam could potentially be filled with electrolytes... "Bty workshop anyone?" "Know thanks, we just eight."

Cheers!

 

[AquaMan]

That "metal foam" stuff has been around for around 2 decades. It's good stuff but it has two problems: You can't weld to it without weakening it, and any bolt run through it tends to crumble the material around the hole.

 

[Artful Dodger]

That "metal foam" stuff has been around for around 2 decades. It's good stuff but it has two problems: You can't weld to it without weakening it, and any bolt run through it tends to crumble the material around the hole.

Yeah, there's been some progress in the past 20 years. FI: brazing.

Shirzadi, Amir & Koçak, M. & Wallach, Eric. (2004). Joining stainless steel metal foams. Science and Technology of Welding & Joining (PDF). 9. 277-279. 10.1179/136217104225012210.

And bolts aren't necessary with a 1-piece diecasting. Components can be attached either by brazing or with adhesives.

Cheers!

 

[MikeAtkinson]

That "metal foam" stuff has been around for around 2 decades. It's good stuff but it has two problems: You can't weld to it without weakening it, and any bolt run through it tends to crumble the material around the hole.

I first came across metal foams 30 odd years ago, but they are much older, first foam in 1926. Potentially very useful, I suspect they are too expensive for general use. They are also not repairable in general.

Tesla would require many times the current world production of metal foams (of all types) for just one model in one factory if they were to use foams for the unibody material. Scaling up to their needs would be a major headache.

Closed cell foams tend to be made by injection of a gas into the melt, but the bubbles are very buoyant, and so it is difficult to make. Perhaps one of the few things easier to make in space than on Earth.

 

[jerry33]

Without squirming under the front of our Models S or X, can someone remind me of the extant radiator coils each model currently has? The follow-up question is: during an extreme atmospheric event like a silicic volcanic eruption - try to imagine the worst conceivable dust storm and you're getting reasonably close - could those coils become compromised enough to reduce their heat-shedding ability so that the cars cannot properly function?

It's really going to depend upon the temperature (also how hard you are driving). If the weather is cool/cold the flaps will stay closed so not much problem. In hot weather they will be open and will clog just like any radiator. So a Tesla won't stop almost instantly like an ICE vehicle when there's no air flow to the combustion chamber.

 

[JRP3]

Oh, and BTW, the voids in the SS metal foam could potentially be filled with electrolytes..

Lest anyone think this is actually a possibility, it's not, for various reasons, but number one would be they are closed cell foams, meaning each pocket is isolated and sealed from the others.

 

[JRP3]

Mate Rimac discussing batteries. Of interest is their temperature control of 2170 cells from top and bottom instead of the sides, the C2 has a 120kWh pack, 6,980 cells, and he doesn't see any major improvements in density in the near term. Rightly dismisses all the click bait headlines of faster charging or higher cycle life "breakthroughs" which don't mention density and/or costs. Doesn't mention Tesla Battery Day however.