Tesla, TSLA & the Investment World: the Perpetual Investors' Roundtable

[Stretch2727]

Someone argued that all cells are risky at the fleet of cars scale, but Tesla just has a better battery management system. Is there any way to quantify the difference in fire risk between cylindrical and large pouch given the same chemistry and BMS? I mean, I’m sure you can’t really change form factor and keep BMS the same, but I’m not sure relatively how much influence form factor has and how much influence a good/bad BMS has.

I tend to think of this as a mechanical problem. With pouch you now have swelling and a weak outer casing so higher risk of a mechanical failure causing an electrical short etc.

Yes a good BMS may detect this failure early but do you really want to take the risk and just rely on detection? Avoiding the possible risk is a better path.

 

[22522]

I continue to find this humorous as it relates to some posters here who disagreed on posts that put forward the same postulate. A blind chipmunk could have found that nut....hey many EV fires are related to pouch cells, that also blow up in drones and all sorts of other things. Hmmm....maybe the pouch format is an issue.

Anyhow, GM is most at risk as far as I can see- they were bragging on the large pouch format. I am really really surprised no one has called attention to this at CNBC- shocked... no really.. Now, after this very public comment from Elon they are going to have to go to extraordinary lengths to avoid having to write off a 2 year investment in battery plants. It was literally the only thing GM had going for it in the EV side of things.

Sad to see one vendor take down so many EV efforts but better now than in 2 years.


Absolutely correct, lots of pouch fires in other applications such as laptops, drones, etc.

Elon is getting an overstated amplification of what he said. Said hard, not impossible. There were a lot of Chevy Volts, correct me if wrong, but I don't remember many more fires than Tesla as a percentage. If you put a cooling plate between each pair of pouches so that each pouch has one side cooled, and you run the coolant at a temperature and pressure such that super cooling efficient boiling heat transfer fixes the max temperature of any hotspots, (just like the pressurized systems used for IC engines) you can keep a large format pouch cell safe.

Like this: https://m.youtube.com/watch?v=h4nM7rXpsJg…

As I understand it, and may be wrong, the Bolt engineers disregarded the temperature clipping and super high heat flux capacity of boiling heat transfer (tuned to the max temp you want to happen) and used conductive metal plates instead.

The solid metal plates have no cooling regime change at hot spots and... I don't see how they could work with more volatile chemistries.

So they cost reduced the Volt battery pack with little appreciation of boiling heat transfer benefits to produce the Bolt battery pack. Likely a similar cultural situation to when all the Korean airlines were running into mountains - A culture that would not accept information from low level engineers (copilots), only high level managers (pilots).

So hard, not impossible.

The large 4680 only works with the continuous thermal connection of one entire edge of the film to what should be a high heat flux, perhaps boiling heat transfer temperature capped, liquid cooling system.

 

[Artful Dodger]

Headwind wasn’t lifting the bike, it was the acceleration.

Going the opposite direction would have resulted in faster times for both vehicles, and likely would not have affected the results.

Headwinds affect the less-aerodynamic vehicle to a greater degree. A strong tailwind would be a relative benefit to the motorcycle vs the Plaid Model S. I still don't think it'd be enough to tip the scales. The two roll-races won by the bikes only resulted in those wins because of poor reaction time by the car driver. It was pretty clear the Plaid had motor on both those bikes, and never lagged due to shifting gears. Wait 'til Tesla uncorks the 200mph top speed.

 

[jkirkwood001]

Here's why I think that the model 2 or whatever it's to be called will have a steering wheel.

It's not because FSD won't be perfected enough for all relevant scenarios and markets yet (but it won't);

It's not because buyers of a 25k car won't pay 40% on top of that for FSD (but they won't);

It is really because one of Elon's stated goals is to make products that people love. Just yesterday he commented on the importance of maximizing happiness. When you remove the wheel, the vehicle becomes not much more than a utilitarian tool to get from point A to B. No longer can you choose to how to lean into the curves of a country road or how to accelerate off the line at a stop sign. And it becomes "less fun" when you take away those options.

For this reason I think Teslas will have steering wheels for a while even after FSD is fully perfected.

You bring up a crucial point, @SN_8. I think people who buy a car will want a steering wheel because they enjoy driving and / or the independence. That won't disappear soon (really, Elon? people liked 'driving' their elevators? I don't think so).

I think the sweet spot for FSD will be:

• robotaxis / car sharing
• cars for affluent, visually-impaired who want independent mobility
• people who can't afford a [edit] non-FSD car plus expensive insurance required for "self-driving" ([edit] such as those convicted of impaired driving)

The rest will want a car they car drive. Time will tell if this is a minority or majority.

A variable is when the up-front cost for FSD will eventually be less than the money saved on insurance.

 

[Unpilot]

A culture that would not accept information from low level engineers (copilots), only high level managers (pilots).

Saw this first hand at two different Flight training facility's.
One had only Captains training with other Captains...because the F.O's could not see a Captain make a mistake...honor and all that.
Second, had Captains only train with instructors....same reasoning.

The US airlines had this culture as well. It lasted into the 80's. Then after lots of preventable crashes and deaths, CRM was started at United Airlines in the early 80's

Elon embodies the culture that is best...IE if you have a better idea tell me. No titles should get in the way of information.

 

[navguy12]

Hrm, the efficiency numbers for the R1S and R1T (480Wh/mi, 490Wh/mi) aren't quite as good as I was hoping to see. For a truck they are not terrible, but I was hoping they'd get to 450Wh/mi. Efficiency is hugely important for EVs. Better efficiency creates a virtuous cycle: more range, less battery, less weight, less cost, leading to even more efficiency. For an EV manufacturer, better efficiency translates to better profits.

I vaguely remember back when the Model 3 EPA numbers first came out there was some discussion that the EPA numbers represent energy pulled from the grid to fill the battery and then run the battery down to zero SOC (on the dyno with the prescribed use profile, of course).

 

[BornToFly]

Saw this first hand at two different Flight training facility's.
One had only Captains training with other Captains...because the F.O's could not see a Captain make a mistake...honor and all that.
Second, had Captains only train with instructors....same reasoning.

The US airlines had this culture as well. It lasted into the 80's. Then after lots of preventable crashes and deaths, CRM was started at United Airlines in the early 80's

Elon embodies the culture that is best...IE if you have a better idea tell me. No titles should get in the way of information.

LOL. Reminds me of a flight I had into Tucson, coming in from the north west. My wife was sitting in the right seat. Tower cleared us for a visual approach (I should have done the instrument approach anyway, but I didn't). The airframe of the plane was blocking my view of the Tucson airport to my 1 o'clock, but I could see Davis Airforce Base right in front of me and mistook that for Tucson International (they are only 4 miles apart). After a minute the Tucson tower came on and asked if I was looking at the right airport? Embarrassed, I immediately realized my mistake and turned a little to the right, where I suddenly had the GIGANTIC Tucson runway staring me in the face. Afterwards my wife asked: "Why didn't you ask me for help, I was looking right at it?" I replied: "I had no idea I needed help!" I explained that if something doesn't look right, she needs to speak up, even though she is not a pilot herself (with as few words as possible, as she usually takes a while to get to the point)!

 

[EVMeister]

Not educational to those in this thread, but a pretty positive look at the Model Y ahead of its introduction to the UK.

 

[Nocturnal]

A not-quite random comment, sneaking it in because….3-day holiday:

Pretty hard for me to agree that time is the ultimate currency. It is, after all, rather hard to take anywhere with you.

That is to say: there’s no such thing as time travel.

I suggest that it's the ultimate asset.

 

[Rarity]

What Chip Shortage?

Impressive, instructive video. As many as 32 car carriers lined up, by far the most that I've ever seen. Delivery lot near or at capacity.

You can also see that the parts logistics is near or at capacity. They'll need to start stacking containers soon.

 

[uujjj2]

And the article didn't specify the tires but the Rivian is available with a street tire (most efficient), sport tire and an off-road tire. I'm confident the range was rated with the most efficient street tire while the off-road tire will likely be the most popular seller. The Cybertruck has a lot more frontal area so I think it will come in at a similar but lower EPA efficiency.

The Cybertruck is longer but does not have more frontal area.

 

[JRP3]

If they had a headwind that lifted the bike could they have run the track in the reverse direction?

It was a cross wind pushing the bike sideways, a particular problem when the front wheel is in the air and you have no steering input. It literally would have pushed him off the track or tipped him over if he didn't back off the throttle and get the front back on the track.

 

[jerry33]

Someone argued that all cells are risky at the fleet of cars scale, but Tesla just has a better battery management system. Is there any way to quantify the difference in fire risk between cylindrical and large pouch given the same chemistry and BMS? I mean, I’m sure you can’t really change form factor and keep BMS the same, but I’m not sure relatively how much influence form factor has and how much influence a good/bad BMS has.

Simple geometry says that the distance from the centre of the pouch cell to the corners is greater than from the centre to the sides. This implies a pouch cell cannot cool evenly, and if you are trying to save weight and costs--which in practice means thinner walls--there will be issues. I suppose you could switch a cell off when overheating by having three temperature sensors on each corner of the pouch (top, bottom, and middle) and other sensors to measure expansion, but that would be a real rat's nest of wiring, or a complex plug in type bus. Either approach would reduce volume for batteries, add complexity, failure points, and costs.

 

[heltok]

Looks like the chip supply is solved. Can’t wait for Austin and Berlin to look like that…

 

[j6Lpi429@3j]

its only a matter of time before those car transporters are modified semis Assuming there are some routes (maybe from factory to port?) that are not perfectly suited to train transport, it might make long term sense to stick some megachargers along the route and use semi-transporters to reduce the freight cost (and emissions)?
If I was elon it would depress me to see so many ICE trucks delivering my zero-emissions vehicles. One step at a time I guess

 

[ninpb]

its only a matter of time before those car transporters are modified semis Assuming there are some routes (maybe from factory to port?) that are not perfectly suited to train transport, it might make long term sense to stick some megachargers along the route and use semi-transporters to reduce the freight cost (and emissions)?
If I was elon it would depress me to see so many ICE trucks delivering my zero-emissions vehicles. One step at a time I guess

Don't forget FSD-giga-loads.

 

[JustMe]

its only a matter of time before those car transporters are modified semis Assuming there are some routes (maybe from factory to port?) that are not perfectly suited to train transport, it might make long term sense to stick some megachargers along the route and use semi-transporters to reduce the freight cost (and emissions)?
If I was elon it would depress me to see so many ICE trucks delivering my zero-emissions vehicles. One step at a time I guess

Fo shizzle!

 

[jhm]

A not-quite random comment, sneaking it in because….3-day holiday:

Pretty hard for me to agree that time is the ultimate currency. It is, after all, rather hard to take anywhere with you.

That is to say: there’s no such thing as time travel.

The yeild curve demonstrates that all currencies bend to time. Moreover, the time dimension of a yeild curve is orthogonal to chronological time. That is, the yeild curve along its whole time domain changes over time. We are really talking about a 3-dimensional object, one dimension for yield and two time dimensions. So in reality a currency like the USD does travel in time, especially this projective time dimension that is orthogonal to our ordinary time dimension.

 

[jw934]

Tweet liked by Elon. I liked it too.

https://twitter.com/x/status/1434154087361093635

 

[Baumisch]

Over time as more and more EV's of varying brands are sold statistical data alone will quantify the difference with regards to fire risk. I suspect we'll see a much higher rate of fires in most EV brands not named Tesla, just my hunch though.

Wasn’t there a thread years back regarding tesla betting on its chemistry which people on here argued being less safe but cheaper ? Someone recall that ?