How can it be so affordable?

HaulingAss

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Remember how EM said he would stop selling cars as soon as they have L5 FSD for robotaxis?
They were estimating a per mile cost of $0.10c.
Ummm, no. I don't remember Elon Musk saying anything remotely similar to that. Maybe you should provide a link if you're going to make claims like that.
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Crissa

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Sigh....No. Listen to Crissa, she knows what she's talking about. It's disheartening to see people using the Internet to state "alternative facts" that are just plain wrong.
They're just excited, I think.

The total heat generated by electrons passing through the tab is the same if it's a narrow wire or a thick (wide) trace like in the tabless. It's just spread out in the latter.

But the mass of the cell layers still heat up ^-^;

The tabless design I hope shows up in more places; by putting the heat generated at the end of the battery, across a wider piece of copper, is brilliant.

-Crissa
 

Crissa

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HaulingAss

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I'm not sure he said "at consumer pricing". What he did indicate is he thought the market price of FSD cars would be considerably more expensive and that if you wanted the lower pricing you had a finite amount of time to get it. Naturally, as supply caught up with demand and others develop FSD, the pricing would lower again. Elon was talking about supply and demand, not stopping the sale of cars to consumers.
 

JBee

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They're just excited, I think.

The total heat generated by electrons passing through the tab is the same if it's a narrow wire or a thick (wide) trace like in the tabless. It's just spread out in the latter.

But the mass of the cell layers still heat up ^-^;

The tabless design I hope shows up in more places; by putting the heat generated at the end of the battery, across a wider piece of copper, is brilliant.

-Crissa
Sigh....No. Listen to Crissa, she knows what she's talking about. It's disheartening to see people using the Internet to state "alternative facts" that are just plain wrong.
Sorry that is often not the case when the discussion is about engineering...thats NOT how resistance works.

Cue the 4680 dunny roll for those that don't get the tabless design: (skip to 11:10)

 
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JBee

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Smaller cars add value because more of them can fit in a loading bay or parking lot or roadway.

-Crissa
Alternative reality perhaps?

Add value to whom? The parking lot owner? Do you pay by length of car for parking? (For something 2 feet shorter than a M3?)

You can't fit any substantial amount more of cars on a roadway because its a foot or two shorter vehicle. FSD would help much more for slipstreaming purposes to reduce consumption and get more units of vehicles over the same road in less time at greater average speeds. Length of vehicle is a mute metric.

I am not saying small cars don't work, I'm saying small cars have depreciating value to customers in comparison to slightly larger ones in a side by side config in particular for manufacturing costs. If you want small, get rid of side by side seating and go 2 seater tandem tadpole trike. 1/5th of the energy and parking and road lanes are a 2 for 1.
 

JBee

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I'm not sure he said "at consumer pricing". What he did indicate is he thought the market price of FSD cars would be considerably more expensive and that if you wanted the lower pricing you had a finite amount of time to get it. Naturally, as supply caught up with demand and others develop FSD, the pricing would lower again. Elon was talking about supply and demand, not stopping the sale of cars to consumers.
Economically there is no incentive for a manufacturer to sell vehicles for $40k if it can make $30k as a robotaxi per year instead.

Its a change in financial modelling as the FSD car becomes a appreciating instead of depreciating asset. As in every FSD car they make makes the company even more money as a robotaxi AFTER it has been manufactured and delivered.

Hence get your FSD Teslas quickly. At a minimum a good sales motivator. :)
 
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Crissa

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Sorry that is often not the case when the discussion is about engineering...thats NOT how resistance works.
Sorry, that's literally how resistance works. The tabless has a shorter electron path for some electrons, but your argument is hideously incorrect vs mass and size.

Alternative reality perhaps?
I live in the reality that there is a fixed amount of space in the physical world. What reality that you live in that doesn't? It does, in fact, matter the number of cars you can fit in a loading zone. There's a reason most taxis have two to three passenger seats - and not needing a driver removes the need for that extra set.

-Crissa
 
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JBee

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Sorry, that's literally how resistance works. The tabless has a shorter electron path for some electrons, but your argument is hideously incorrect vs mass and size.
So are you saying that the tabless design does reduce electrical resistance because the path is shorter than with a tabbed design?
 

ajdelange

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With tabs along the entire edge of the anode current collector the longest current path (from the opposite edge of the strip) is 80 mm. With the single tab some current would have to travel sqrt(800^2 + 80^2) = 803 mm. So yes, the electrical impedance is less as is the thermal impedance in the "tabless" design.
 

JBee

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With tabs along the entire edge of the anode current collector the longest current path (from the opposite edge of the strip) is 80 mm. With the single tab some current would have to travel sqrt(800^2 + 80^2) = 803 mm. So yes, the electrical impedance is less as is the thermal impedance in the "tabless" design.
Exactly. That is why the 4680 is better and will likely be able to charge faster without overheating despite being a larger diameter battery.
 

HaulingAss

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Sorry that is often not the case when the discussion is about engineering...thats NOT how resistance works.

Cue the 4680 dunny roll for those that don't get the tabless design: (skip to 11:10)

Crissa didn't say it as precisely or accurately as possible because the bulk of the heat is not generated in the tab itself but via the electrons moving positions within the cell as it is charged and discharged. Other than that, her explanation is what you need to pay attention to.

But I love it when someone posts a lengthy video to supposedly prove their misguided ideas correct, especially when said video does nothing of the sort.
 

ajdelange

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If we assume that each infinitesimal area located at (x,y) on an 80 x 800 mm current collector collects the same amount of current and that that current flows directly to the first place it can get out of the cell, i.e. the single tab in a tabbed design or the tab closest to it in the "tabless" design then the heat dissipated in delivering that current is proportional to y in the tabless design and sqrt(x^2 + y^2) in the tabbed design and integrating over the collector we see that the tabless design will dissipate 1/10th as much heat as the tabbed design in collecting the same current.
 

HaulingAss

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Exactly. That is why the 4680 is better and will likely be able to charge faster without overheating despite being a larger diameter battery.
No, the overall charge rate of the 4680 is roughly the same as the smaller cells due to the need to remove more internal heat. The size of the 4680 cell was chosen to maximize cost efficiencies of the manufacture of the cells and the assembly into battery packs, not to increase charging speed.

Undoubtedly, there will be some small differences, one way or the other, but not really significant in the grand scheme of things.
 

ajdelange

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No 133 addresses the I^2R losses from current flowing in the current collector but the argument applies equally well to heat generated adjacent to infinitessimal area dA by an exothermal reaction in the anode itself. Thus the electrical and thermal impedances are both substantially reduced by this geometry.
 
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