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New Pack Architecture that is Likely Used in P100D and New TE Products

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What's the W/(m*K) of a Model S cell?
Would there really be that much of a difference if the thermal conductivity of the cell walls are good and they design the cell cap to reduce heating? Even in the old design, probably only 1/4 of the cell was in contact with the coolant pipe.
Nah, the cell wall is really thin so I doubt it's adding much. Just think, the cell is 65-70mm long. For analogy, think of any modern CPU cooler. They all have heatpipes. Even pure copper won't effectively move the heat distances in that same range. Basically you'd hope the thermal conductivity of the cell is somehow better than pure copper. What the shell made out of, Nickel?
 
What's the W/(m*K) of a Model S cell?
If it's aluminum like most 18650s, then the conductivity will probably be about 204 W/m*K.

From the patents, the conductivity of the interface layer is only about 5 W/m*K (it specifies different designs from "preferably" above 0.2W to 1W to 5W). Wouldn't the bottle neck be there anyways, with the cell walls being much more conductive?

And just for reference about the relative thermal contact area, from my calculations:
18650 (old cooling loop): 329 sq mm in contact, 7.6% of surface area
2170 (bottom cooling): 346 sq mm in contact, 6.5% of surface area

Nah, the cell wall is really thin so I doubt it's adding much. Just think, the cell is 65-70mm long. For analogy, think of any modern CPU cooler. They all have heatpipes. Even pure copper won't effectively move the heat distances in that same range. Basically you'd hope the thermal conductivity of the cell is somehow better than pure copper. What the shell made out of, Nickel?
Well, I just did a new build with a i5-6500 (TDP 65W) and it doesn't have heat pipes, just the stock cooler with a regular aluminum heat sink and fan. From the i7 line it can go up to a TDP of 140W.

The Tesla cells discharge at a max of 1600A, with 74 in parallel working out to 21.6A each. Assuming 0.04 Ohms internal resistance (as per some other similar Panasonic cells) that works out to 18.7W.

Also, my understanding of the goal of the heat pipe in computers that have them is not because of trying to reduce the temperature differential on the heat sink (it may very well be close to uniform), but rather to separate the cooling fins from the CPU (actually increasing the temperature differential from one end of the cooling system to the other). This is a similar idea to air conditioning.

From the patents, the cooling tube is 30mm tall. So distance to both caps is 17.5 mm from the edge of the pipe. So there is still some distance.
 
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What's the W/(m*K) of a Model S cell?

Nah, the cell wall is really thin so I doubt it's adding much. Just think, the cell is 65-70mm long. For analogy, think of any modern CPU cooler. They all have heatpipes. Even pure copper won't effectively move the heat distances in that same range. Basically you'd hope the thermal conductivity of the cell is somehow better than pure copper. What the shell made out of, Nickel?

What if Tesla drops a separate heat pipe into the gap between cells, connected at the bottom thermally but isolated as a gas volume from the main structure for simplicity and to prevent leaks?

In past versions with the coolant snake, I believe they've been filling this space with intumescent goo to handle a shorted cell thermal runaway, but I'm thinking the heat pipe system might be effective enough in distributing heat to prevent that passively anyway - if the cell has enough cooling contact area, which supplemental pipes in the gaps between cells might provide.
 
Thermal gradients bad.
The original design had thermal gradients. The old coolant pipes only touched a small section of one side of the cell, which meant heat transfer needed to move across electrodes, separators, and electrolyte. One side of the cell had to be significantly hotter than the other. The new bottom contact system means heat can move along the length of the electrodes. I'm willing to bet Tesla didn't choose that because it's worse.
 
Notes from the Jan 4 Gigafactory Tour:

1. I could not get a straightforward answer wrt whether 2170 cells destined for a vehicle rather than a PPack would have casings of different thicknesses. I was, on the other hand, told very adamantly that the chemistry was slightly different, in that the one is designed for deep discharge. I would eat the GF lobby wall's live garden, however, if that meant NMC vs NCA - that sort of difference would entail entirely different production lines.

2. The PP V.1 and V.2 most definitely have different coolant systems, as all here well understand. We were not, of course, permitted to photograph, but I saw the coolant lines' exit sites and, if Vlad or others can direct me to known or suspected cartoons (from patents, perhaps) of various setups, I might be able to provide better direction.

3. The data placard on a finished PP2 had information...unfortunately, we were shepherded by at such a rate that I couldn't snag all of it; all my notes show are "215kWh" and "900V". Not the most salacious of data but it's all I snagged.
 
2. The PP V.1 and V.2 most definitely have different coolant systems, as all here well understand. We were not, of course, permitted to photograph, but I saw the coolant lines' exit sites and, if Vlad or others can direct me to known or suspected cartoons (from patents, perhaps) of various setups, I might be able to provide better direction.
Where exactly did you see these coolant lines? Did you see v2 battery modules, where you can see the cells? Did you see battery pods, where you couldn't see the cells, more like a metal box 2x2 feet?

3. The data placard on a finished PP2 had information...unfortunately, we were shepherded by at such a rate that I couldn't snag all of it; all my notes show are "215kWh" and "900V". Not the most salacious of data but it's all I snagged.
The 900V reference is interesting, and new. Maybe the Powerwall is 450V and the Powerpack is 900V. This would mean connecting two and two pods in series. 500V is a limit Tesla shouldn't exceed for domestic installations, 900V should however be fine for commercial installations.

I'm not sure it's very significant, though it might mean the Model 3 battery pack may be 450V rather than 400V. That should improve effficiency somewhat.
 
The problem of NCA and NMC is that, while they are extremely similar in their end-state, they are different enough in their raw material make-up that yes, the lines would need to be dedicated. Now, the GF is so immense that isn't a production problem; it does mean, however, less flexibility in the use of the plant.

Regardless, we can definitively say that, for example, a portion of the facility is to be used to build motors and windings, so, upon reflection, I'll take my earlier statement back: Tesla may have been willing to give up such uniformity and most definitely could have pre-allocated some of the building's blocks for NMC, others for NCA.
 
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Notes from the Jan 4 Gigafactory Tour:

1. I could not get a straightforward answer wrt whether 2170 cells destined for a vehicle rather than a PPack would have casings of different thicknesses. I was, on the other hand, told very adamantly that the chemistry was slightly different, in that the one is designed for deep discharge. I would eat the GF lobby wall's live garden, however, if that meant NMC vs NCA - that sort of difference would entail entirely different production lines.

2. The PP V.1 and V.2 most definitely have different coolant systems, as all here well understand. We were not, of course, permitted to photograph, but I saw the coolant lines' exit sites and, if Vlad or others can direct me to known or suspected cartoons (from patents, perhaps) of various setups, I might be able to provide better direction.

3. The data placard on a finished PP2 had information...unfortunately, we were shepherded by at such a rate that I couldn't snag all of it; all my notes show are "215kWh" and "900V". Not the most salacious of data but it's all I snagged.

The Patent used for the OP in this thread has several cartoons of different setups. The PDF is available here. There is a button for downloading PDF version of the standard in the middle of the screen on the left side of the page.
 
This earlier Tesla patent application appears to give details of the printed-circuit used in this system, including the use of narrowed traces a fusible links:
Patent US20140212695 - Flexible printed circuit as high voltage interconnect in battery modules

I found it relevant.

Interesting ... double bonding to individual cells to prevent link fatigue. Thanks for the post :cool:

upload_2017-1-9_7-44-6.png
 
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The problem of NCA and NMC is that, while they are extremely similar in their end-state, they are different enough in their raw material make-up that yes, the lines would need to be dedicated. Now, the GF is so immense that isn't a production problem; it does mean, however, less flexibility in the use of the plant.

Regardless, we can definitively say that, for example, a portion of the facility is to be used to build motors and windings, so, upon reflection, I'll take my earlier statement back: Tesla may have been willing to give up such uniformity and most definitely could have pre-allocated some of the building's blocks for NMC, others for NCA.
It's well known that Tesla uses NMC for their 18650-based Tesla Energy products. It would be extremely odd if this were not the case with the 21-70s as well.

This is my estimate for dedicated production lines, and Tesla should (more or less) be able to meet the required production volumes, even with difficulties along the way:
Gigafactory ramp4.png


But a quick yes/no question that would be quite helpful - did you see heat pipes in any shape or form? They would probably look something like this:

heatpipe_cs.jpg


-font-b-Customized-b-font-DIY-laptop-CPU-GPU-Flat-copper-font-b-heat-b.jpg
 
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It's well known that Tesla uses NMC for their 18650-based Tesla Energy products. It would be extremely odd if this were not the case with the 21-70s as well.

This is my estimate for dedicated production lines, and Tesla should (more or less) be able to meet the required production volumes, even with difficulties along the way:
View attachment 209792
Informative. Mostly I tend to agree with your optimistic views but I'll wager the low end Model 3 (the ones you call 55) will also be delivering at launch, if only to prove the point that they have met the $35,000 goal. Obviously any change in mix will greatly affect battery needs.

I also think the almost entire world underestimates the potential for large scale energy storage and solar/wind power on islands everywhere.

I admit my bias because I powered an island I owned entirely with solar power back in 1989; it's still there producing away for zero marginal cost. The payback period for the entire installation then was one year, because diesel fuel had to be imported from a refinery may islands distant. There are many competitors but this is bringing faster growth than are BEV, including Tesla and Model 3. Why: for the first time the prices of solar and wind are definitely cheaper and more reliable than fossil fuels, including grid storage.

Therefore I think you've underestimated PowerPack demand by a factor of ten or so. Who at Tesla recently said that non-automotive energy storage products would consume ~90% of GF total finished production?
 
The original design had thermal gradients. The old coolant pipes only touched a small section of one side of the cell
The new architecture only touches a small section of the cell too, except the old one was in the middle, and the new one has the top end 70mm away???

I'm willing to bet Tesla didn't choose that because it's worse.
I'm not. In a race to have the quickest car and most range, anything can go.
 
Therefore I think you've underestimated PowerPack demand by a factor of ten or so. Who at Tesla recently said that non-automotive energy storage products would consume ~90% of GF total finished production?
I haven't estimated demand at all, just supply. I expect demand to exceed supply for the overseeable future.

(The Model 3 revenue includes all value added by Fremont.)
 
What if Tesla drops a separate heat pipe into the gap between cells, connected at the bottom thermally but isolated as a gas volume from the main structure for simplicity and to prevent leaks?

In past versions with the coolant snake, I believe they've been filling this space with intumescent goo to handle a shorted cell thermal runaway, but I'm thinking the heat pipe system might be effective enough in distributing heat to prevent that passively anyway - if the cell has enough cooling contact area, which supplemental pipes in the gaps between cells might provide.

If the heat pipe extends vertically into the gap between the cylindrical cells, that would solve the issue. But expensive and heavy.