Investor Engineering Discussions

[MP3Mike]

What do you guys think about the fact that Tesla is trying to use DBE (which is supposed to be better and cutting edge) in their cells when Jeff's group just found a liquid electrode that even beats their newly designed NMC352 cell? Will Tesla take Jeff's work and move it into storage only, even though Elon said that will be using LFP? Trying to figure out why Jeff and his team work for Tesla if they are not going to use his new findings....

Or will DBE be used only for transportation to keep costs down?

DBE has nothing to do with electrolyte. DBE just applies to making the cathode and anode. (DBE cells still require a liquid electrolyte to be injected once they are assembled.)

Even normal electrodes made with the wet process are assembled into cells when they are dry. The electrolyte essentially activates the cell.

So Jeff Dhan's work probably still applies. (But may be able to be optimized specifically for DBE cathodes/anodes.)

tl;dr: Don't confuse the electrode and electrolyte with each other.

 

[ggies07]

DBE has nothing to do with electrolyte. DBE just applies to making the cathode and anode. (DBE cells still require a liquid electrolyte to be injected once they are assembled.)

So Jeff Dhan's work probably still applies. (But may be able to be optimized specifically for DBE cathodes/anodes.)

ha! you are right...have no idea where my head was...thanks.

 

[ZsoZso]

Just another general side-note about information you see in Jeff's slides or papers published from his group (which applies to the above presentation as well as anything else you see publically posted):
Their contract with Tesla requires them to submit to Tesla any material before publication for review and approval.
Tesla can request specific data / slides / information to be removed from the material before it is approved for publication.
In other words, you will not see any "secret sauce" that Tesla wants to keep for themselves published by the group.
Put it another way: they may have more leading edge stuff -- not included in the presentation, that is actually even better than what is included

ps: don't ask me how I know

 

[JRP3]

Dillon looks into the new battery chemistry

 

[willow_hiller]

New compact antenna design for GPS in Tesla patent filing: Tesla applies to patent more precise GPS antenna for self-driving and navigation

It's got this interesting concentric spiral shape, and is made to fit in the module with the forward facing cameras:

Maybe one component of HW4?

 

[mongo]

New compact antenna design for GPS in Tesla patent filing: Tesla applies to patent more precise GPS antenna for self-driving and navigation

It's got this interesting concentric spiral shape, and is made to fit in the module with the forward facing cameras:

Maybe one component of HW4?

I'd expect this to be used in all cars going forward. Continuous improvement.
I think spiral is for ice melt.

Point of clarification, due to Fred headline issue: it's a ((more accurate positioning system) antenna), not a (more accurate (GPS antenna)).
The antenna itself not more accurate (all GPS type are non-directional). The accuracy comes from the wider frequency range which allows the reciever to use multiple constellations (GNSS) vs. only the US GPS system.
GNSS vs GPS - What is the Difference? - Spirent

 

[mongo]

Here is a snippet that caught my attention, and I thought it didn't make sense to me. Cathode is the "positively" charged end of the battery that discharges electrons ?

The cathode is positive. Conventional current flow travels from positive to negative. Depending if they meant discharge as emit or as to lose potential, that part is questionable.

 

[mongo]

Can you link to Bjoern´s video you mention? I have never been limited on the V3 chargers I have used in Europe (only by my own battery´s state of charge). From what I know, V3=250kW per stall independent, V2=150kW per 2 stalls shared. Maybe this has something to do with the different connectors? In Europe, the V3 chargers have only CCS connectors.

Each pedestal can do 250kWh, but the power input to the cabinet can't do 250kWh to all the pedestals at the same time. AC+DC < 1000kWh, but comes close. AC along definently can't based on published ratings plates.

 

[MP3Mike]

Can you link to Bjoern´s video you mention? I have never been limited on the V3 chargers I have used in Europe (only by my own battery´s state of charge). From what I know, V3=250kW per stall independent, V2=150kW per 2 stalls shared. Maybe this has something to do with the different connectors? In Europe, the V3 chargers have only CCS connectors.

@hobbes you likely wouldn't be limited unless the site suffered a once in a lifetime event of every stall being plugged in to a car, that was pre-conditioned, at a low SoC, all at the same time. (Because a given car is only at 250kW for such a short period of time.)

Yep, here is the video with the starting point for you:

He just guesses at the 200kW if every stall was plugged in at the same time, but he understands that not every stall is guaranteed 250kW all the time.

But if you want to know for sure next time you are at a V3 site take a picture of the spec plate on the cabinet and share it, like the one I posted that showed the ~350kW input to the cabinet that supplies 4 stalls. (I highly doubt you have different cabinets in Europe.)

Edit: note that the whole Bjorn video is pretty good, he talks about how Ionity is different than Tesla and other charge networks, in that they will only install chargers that can be guaranteed 350kW. So if a site can only get 1.4MW of power they will only put 4 stalls. Where other charge networks would put 8, sharing the power. (Kempower has data showing that the average usage is only ~70kW per stall.) So Ionity is guaranteeing a good experience if you can plug in, but in a lot of sites that ends up creating a bad experience because you have to wait in line before you can plug in and get that experience.

 

[JRP3]

Long video with Sandy Munro discussing some of his history and the future of EVs. Nothing really new for most of us though he does say the 4680 cell is cheaper and more powerful than he expected.

 

[mongo]

@insaneoctane @Gigapress
If I might jump in with a thought. Along with aero and rolling, we need to also consider base load. Engine efficiency includes engine loses along with thermodynamic efficiency to get overall crankshaft energy/ per unit fuel. If we split off pumping and friction losses as part of the base load from thermal efficiency (assuming we are operating in a region of equivilent efficency), it allows for a different look at the analysis.

EVs are not just optimized in terms of kWH to mechanical HP, but in all areas. Bearings, tires, gearbox, HVAC, power steering are all optimized for minimal energy usage. So baseload and rolling friction are a small portion of the energy pie. That means a change in aero load has a high coupling to change total energy usage.

ICE, on the other hand, uses a lot of energy just spinning. With this larger base load contribution of the engine plus increased rolling losses due to the transmission, aero is a smaller portion of the pie. Due to this, a change in aero load will produce a smaller percentage change in total energy usage compared to an EV.

 

[Gigapress]

@mongo nice! I’m working now on building a better model for comparison because what I put out yesterday just used constant energy efficiency for all miles driven for simplicity.

I did some math here that shows Tesla’s advantages in drag coefficient and propulsion efficiency mean that a typical 6 miles per gallon diesel truck is roughly equivalent to a Tesla Semi doing the same route for 1.9 kWh/mile, in line with Tesla’s claimed <2kWh figure.

6	Mpg for diesel truck
40.7	kWh per gallon of diesel
6.78	kWh per mile for diesel truck
35%	Diesel propulsion efficiency
2.37	Propulsion work (kWh) per mile for diesel truck
70%	Percentage of work being for aero drag at 70 mph
0.6	Diesel truck drag coefficient
0.36	Tesla Semi drag coefficient
0.66	Savings in aero drag kWh per mile
1.71	Net Tesla Semi kWh per mile propulsion work
90%	Tesla Semi propulsion efficiency
1.90	Tesla Semi battery drain kWh/mile
4.9	Energy savings kWh/mile
72%	% Energy saving
This applies for typical highway speeds maybe 65-70 mph on flat ground with average rolling resistance, whatever conditions yield the 6 mpg for the diesel truck.
Conclusion: Tesla's stated < 2 kWh per mile is probably right

 

[mongo]

@mongo nice! I’m working now on building a better model for comparison because what I put out yesterday just used constant energy efficiency for all miles driven for simplicity.

I did some math here that shows Tesla’s advantages in drag coefficient and propulsion efficiency mean that a typical 6 miles per gallon diesel truck is roughly equivalent to a Tesla Semi doing the same route for 1.9 kWh/mile, in line with Tesla’s claimed <2kWh figure.

6	Mpg for diesel truck
40.7	kWh per gallon of diesel
6.78	kWh per mile for diesel truck
35%	Diesel propulsion efficiency
2.37	Propulsion work (kWh) per mile for diesel truck
70%	Percentage of work being for aero drag at 70 mph
0.6	Diesel truck drag coefficient
0.36	Tesla Semi drag coefficient
0.66	Savings in aero drag kWh per mile
1.71	Net Tesla Semi kWh per mile propulsion work
90%	Tesla Semi propulsion efficiency
1.90	Tesla Semi battery drain kWh/mile
4.9	Energy savings kWh/mile
72%	% Energy saving
This applies for typical highway speeds maybe 65-70 mph on flat ground with average rolling resistance, whatever conditions yield the 6 mpg for the diesel truck.
Conclusion: Tesla's stated < 2 kWh per mile is probably right

Nice! In the semi thread I came up with (optimistic) 1.6kWh/mile with low resistance tires and 50% aero 50% rolling load. Tack on base load and efficiency, and it's still under 2.

 

[MP3Mike]

You would think that one CCS implementation would be the same as another, given that CCS is a standard. Having worked most of my career in computer communications, and having experienced this adapter in a Tesla, I would tell you that the world is more complex than that... and, IMHO, CCS could use a certified interoperability testing program. (If it has one now, it is sorely lacking)...

@growler23 and just as you say that CharIN announces their new CharIN Conformance Test System (CCTS).

Apparently you can't just leave everyone to develop to the standard on their own.

 

[growler23]

@growler23 and just as you say that CharIN announces their new CharIN Conformance Test System (CCTS).

Apparently you can't just leave everyone to develop to the standard on their own.

Cool! Thank you for posting that! Yes, that is exactly what I was talking about. And if CharIN's test is solid enough that it actually produces interoperability from both vehicles and chargers, that is huge. Because that ain't the case out there on the North American road right now (I hear Europe is fine though), and as millions more buy EVs, it becomes a nightmare.

<soapbox>
There need to be 3 things for this CCS to scale as well as needed in North America for the next few years:
1) A solid, precise, implementable standard. Hopefully CCS is that (haven't read it but not impressed by variance in implementations, so: questionable here)
2) A very hard-to-please interoperability test system - CharIN says they have that. I hope it is VERY finicky about checking state machines and timing.
3) A recognizable logo, that you can be sued for faking, reserved for use on vehicles and chargers that pass the test. CharIN wants their logo to be that.
If those are all in place, North American CCS plugging in should stop being as much of a crapshoot as it is right now. I know my Setec adapter probably made my experience worse than your average North American VW owner, for example - but I have seen PLENTY of comments in PlugShare from non-Tesla folks about chargers not working due to some handshaking mystery or another. That HAS to stop - it needs to be so seamless that the dubious public doesn't even realize computers are involved, negotiating between each other.
</soapbox>
Related, the other CCS charging issue I've seen is that many don't have the uptime that Tesla does: over 99.9%. With the government money coming from the Bipartisan Infrastructure Law, and FINALLY seriousness about looking at getting chargers along our highways (every 50 miles is the DOT/DOE goal), I wonder if someone (DOE maybe) could certify charging networks that show over 99% uptime, and make a badge/logo for that. Charge networks would quickly up their game IMHO as users quickly learned to ignore ones lacking the badge since they might not be able to charge when you get there.

 

[MC3OZ]

Interesting new battery tech:-

 

[MC3OZ]

Not the point about the number of manufacturing steps for cell form factor in this video:-

Cylindrical and prismatic about the same number of steps, pouch more steps,

If CATL/BYD LFP cells made in China are cheaper than Tesla could make 4680 LFP cells, the difference isn't form factor.,

There are lots of reasons why Chinese made cells might be cheaper, but Chinese cells are subject to a 10% duty when imported into the US, and similar duties probably apply to the EU.

I would contend that if cells are being made in the US or the EU the Tesla 4680 production process is very competitive on price, perhaps the cheapest method,.

If we call the Aluminium Graphite cell above "Agr" IMO the cell types Tesla could potentially make with with 4680 lines include Agr, NCA, MNC, LFP, LMFP, LMNO, Sodium.

Many battery chemistries use much the same type of production equipment and can be made in variety of form factors.

Where a funky new type of battery requires new manufacturing processes or a specific form factor, that is a disadvantage.

When Elon talks about Manganese, I don't know if he means NMC, LMFP or LMNO, perhaps he means all 3.

The 4 Million Mile battery is MNC at least the variant we know about is. We know Tesla has a patent for a single crystal cathode process, so my guess is an intention to make 4 Million Miles batteries in 4680 format.

For LMFP I don't know if the chemistry is owned by CATL, Tesla or both. If CATL owns LMFP Tesla might be able to license the rights on reasonable terms.

While the Australian Agr cell chemistry is new and might not scale, it has a number of advantages, the principle one being the supply chain is mostly Aluminium and Methane. It has a number of advantages for regen braking and fast charging, while energy density is currently a disadvantage.
If the energy density can be improved it is a candidate to be made in 4680 format. For energy storage, the energy density doesn't matter, and the high power density can be useful in some applications.

If Tesla stays in the loop on new chemistries, they can if needed license the rights to make those chemistries in 4680 format, at a future date, when that makes sense.

 

[mongo]

Wow. This might be worth going in depth more on the engineering thread. Lots of good design speculation for Cybertruck and I think Connecting the Dots is right on every prediction. Big implications for the specs and manufacturing cost for Cybertruck.

Their understanding of antilock brake systems seems lacking. Brembo system is an interesting idea, but not failsafe in the pure electic form. Though neither is hydraulic depending on the mechanical fault. Pedal pulsation could be eliminated from standard ABS setup.
Steering wheel already has absolute position encoders. Pure steer by wire is not failsafe, variable rate steering can be.
Tesla has a patent for an electric rear steering system (both wheels together). 4 wheel fully independent seems like a lot of extra parts for little gain.

 

[Buckminster]

This diamond turn will certainly turn heads:

 

[JRP3]

This diamond turn will certainly turn heads

It's only speculation at this point and ignores the added engineering required for what is basically a party trick. I kind of hope they don't waste the time enabling this.