Tesla 4680 battery

With the battery as the platform, what happens when the battery dies or has problems? Also occupants sitting on a battery like that?? Doesn't sound great to me. What about the danger of fires?
The 4680 will go directly into the car's chassis and Tesla claims the cells will be bonded (glued) in for greater strength. Who knows how repairable, or even if, it will be.
 
The 4680 will go directly into the car's chassis and Tesla claims the cells will be bonded (glued) in for greater strength. Who knows how repairable, or even if, it will be.
If anything, Tesla will want those packs going back to the Gigafactory just for disassembly of the bonded cells. And then the spent 4680s might go to a 3rd party logistics vendor for recycling unless Tesla creates a closed-loop system to handle them. Much like how Toyota has Panasonic handle their battery packs once sent back to a parts warehouse.
 
Well, that's the brilliance behind the 4680. It's designed and packaged to adequately deal with the thermal issues. First by being tabless, reducing internal resistance, and therefore heat. Second by it's designed in ability to transfer heat through the top and bottom, instead of the sides. Tesla is well aware of the larger roll reducing heat transfer through the sides.

The conduction of heat through the sides has always been problematic, as it must travel from the center of the cell, through a number of insulators and out into the case. Not so with the 4680.
This is far from the only cell made like this. And from some very reputable suppliers

The axial vs radial conduction is also nothing new. Plenty of designs that have done that. I have overseen designs of this type, significantly leveraging the bussing to get heat out, myself years ago for systems I can’t disclose. it works reasonably well, though dielectric standoff and other considerations come into play relative to systems integration.

I don’t quite understand your rationale of why you say “not so with the 4680.“ The jelly roll will still have the issue of radial heat transfer due to the sandwich of polymeric separator in there. The only thing that changes is the crushed end which I discussed earlier. On true cyclic high rate operations, it will still get HOT in the center. Depending on how the terminals and case isolation are done, other issues can arise.

Tesla is making use of concepts that were done elsewhere for other reasons in the past many years.
 
What tis means is that the batteries will burn hotter and their location being under the seat of the passengers will insure that the rest of the car remains salvageable after is has finished cooking off. :ROFLMAO:
 
This is far from the only cell made like this. And from some very reputable suppliers

The axial vs radial conduction is also nothing new. Plenty of designs that have done that. I have overseen designs of this type, significantly leveraging the bussing to get heat out, myself years ago for systems I can’t disclose. it works reasonably well, though dielectric standoff and other considerations come into play relative to systems integration.

I don’t quite understand your rationale of why you say “not so with the 4680.“ The jelly roll will still have the issue of radial heat transfer due to the sandwich of polymeric separator in there. The only thing that changes is the crushed end which I discussed earlier. On true cyclic high rate operations, it will still get HOT in the center. Depending on how the terminals and case isolation are done, other issues can arise.

Tesla is making use of concepts that were done elsewhere for other reasons in the past many years.
There is no question Tesla is using a large number of existing ideas and putting all into one product. I am unaware of anyone else doing the same design. For an example of a similar design aspect, BMW’s battery packs were bottom cooled, just like the 4680 pack is “planned to be”.

As I understand it, Tesla feels single sided, bottom cooling is sufficient with the 4680, with the sides being insulated! maybe this is due to lower internal resistance than any other item. So if I were to guess at a location for a potential hotspot, it might be somewhere near the top, mid roll. Of course, real world applications have a way of shining a light on a designs limitations.

I feel it’s the best EV battery solution as it “seems” to address a number of issues. Time will tell, and the competition is cranking up. I do wonder why it’s taking so long.


On another note, battery energy density/specific energy is not improving at a rate sufficient to compete with fuels. I used the example of NASCAR vs Plaid. Both are around 1000HP, one of them runs out of power after fewer Daytona laps than fingers on one hand.
 
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@Cujet , @OVERKILL and others please chime in...
This article claims:
"The 46 millimeters wide, 80-millimeter long battery cell will increase energy density by five times, increase range by sixteen percent, and improve power output by six times."

What does this mean in layman's terms? "Increase range" sounds self-explanatory and good, regardless. "Improve power output" means what to a Model 3 owner, like me?
Perhaps best of all, the article suggests advancements in battery tech like this gets EVs closer in price parity with ICE vehicles.
Your thoughts? Thanks in advance.

I am considering another Tesla is perhaps a year if and when EV technology takes a decent step forward over our 2018 Mid Range. By the way, the Kato Road facility is near the Fremont factory and the new battery factory is just east of Fremont in Lathrop, CA (hot Central Valley).

Tesla 4680


and now we know.......

wow.

Screen Shot 2022-04-08 at 12-1.33.09 PM.jpg
 
Plus higher sustained bi directional throughput, better cooling, lighter weight,

Thing should swallow 250KW for a good long time before ramp down.

This car also uses the pack as structure and has both giant castings (pretty sure)
 
Can’t help with technicals, but 5x the always sounds good. So batteries 5x smaller too? It’s not done yet.

Some folks going to pay homage to the Elon.
1649607919736.jpeg
 
Plus higher sustained bi directional throughput, better cooling, lighter weight,

Thing should swallow 250KW for a good long time before ramp down.

This car also uses the pack as structure and has both giant castings (pretty sure)
In reality better cooling is achieved by skinnier cells. The number of wraps in the jelly roll is an impediment unless the cell is designed for much lower impedance and much higher thermal conductivity through the ends. Even then dielectrics become a concern.
 
Can’t help with technicals, but 5x the always sounds good. So batteries 5x smaller too? It’s not done yet.

Some folks going to pay homage to the Elon.
It's just not true. Lithium is king and we already use all the ions. As I continue to say, we can move only so many ions, as there are just so many to move.

Nothing in these "new 2x or 5x batteries" addresses the physics behind the very real limitations of electrochemical energy storage.

I remain convinced that the 4680 will be the best choice for modern EV's. I also remain convinced that further battery improvements will be mildly incremental in nature. Better packaging, tighter tolerances, tweaked chemistry. The "real world" assessment is now a 10% improvement in the next decade.

Even the promised "solid-state" battery is just an incremental improvement, with a "best case" 30% reduction in size. That 30% will be partially offset by the need to have extremely strong cases. And the need to operate at a higher temperature of 180°F.
 
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on a sep note that model does not exist??

I suspect the existing pack will becomes the standard versions and the 4680 the extended or long distance version.
 
In reality better cooling is achieved by skinnier cells. The number of wraps in the jelly roll is an impediment unless the cell is designed for much lower impedance and much higher thermal conductivity through the ends. Even then dielectrics become a concern.

I suspect the tabless design has some benefit here as the current doesn't have to push through the midway point of the cell?
 
Even the promised "solid-state" battery is just an incremental improvement, with a "best case" 30% reduction in size. That 30% will be partially offset by the need to have extremely strong cases. And the need to operate at a higher temperature of 180°F.
Latest article I saw on solid state batteries didn't show a temperature near that high, in fact, lifespan was negative impacted if temperature wasn't tightly controlled. This is, I believe dictated by the anode material.
 
Latest article I saw on solid state batteries didn't show a temperature near that high, in fact, lifespan was negative impacted if temperature wasn't tightly controlled. This is, I believe dictated by the anode material.
It will be quite interesting to see this stuff mature. I know I have a tendency to disbelieve claims, mostly because so many are untrue, that when honesty comes around, I fail to see it. However, from a very simplistic point of view, a non liquid or slightly-liquid electrolyte (catholyte) has high resistance at low temperatures. That's simply the nature of a chemical battery. My guess (and I do so hope to be wrong) is that claimed good Solid State battery performance at low temperatures is relative to other designs, and not to the 100% rating at higher temps.
 
I suspect the tabless design has some benefit here as the current doesn't have to push through the midway point of the cell?
???? Current doesn’t push through the midpoint of the cell. The tabs are inserted on either end of the jelly roll in tight contact with the electrode (anode or cathode coating ends just before it usually). Those tabs are laser welded to the can case in designs that use a crimp seal, or else a lead is literally run through the cell on designs that have terminals both on the same end.

Designs with high thermal conductivity have the electrode foils making really good contact to at least one end of the cell, which allows for heat transfer to the end and to the case.

The jelly roll heat issue is related to current density. Heat is I^2 x R, so unless the electrode isn’t producing current in the innards, what happens is that the heat generated there can have a harder time getting out. It’s pretty well insulated in there with poor radial thermal conductivity. The outer wraps of the jelly roll aren’t a lot better, but they are closer to the wall which helps if the wall has a means of shedding heat (which is often tough because if the cell case is conductive and the battery is floating, you need additional dielectric).

So there’s art, science, and finding balance in high power battery designs.
 
???? Current doesn’t push through the midpoint of the cell. The tabs are inserted on either end of the jelly roll in tight contact with the electrode (anode or cathode coating ends just before it usually). Those tabs are laser welded to the can case in designs that use a crimp seal, or else a lead is literally run through the cell on designs that have terminals both on the same end.

Designs with high thermal conductivity have the electrode foils making really good contact to at least one end of the cell, which allows for heat transfer to the end and to the case.

The jelly roll heat issue is related to current density. Heat is I^2 x R, so unless the electrode isn’t producing current in the innards, what happens is that the heat generated there can have a harder time getting out. It’s pretty well insulated in there with poor radial thermal conductivity. The outer wraps of the jelly roll aren’t a lot better, but they are closer to the wall which helps if the wall has a means of shedding heat (which is often tough because if the cell case is conductive and the battery is floating, you need additional dielectric).

So there’s art, science, and finding balance in high power battery designs.
I need to go dig up the drawing and vid that referenced this location.
 
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