stopcrazypp
Well-Known Member
Cell production will not start however until later this year. Right now they are only doing powerwalls and powerpacks using cells shipped from Japan.
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Johan
Ex got M3 in the divorce, waiting for EU Model Y!
It's operatioal in the sense of assembling packs (Tesla Energy products) from Japanese cells. Cell production hasn't started there as far as anyone is informed.
If they were making batteries at the Gigafactory now, it would be very difficult to cover up the movement of raw materials. There would be railcars of the stuff going there and I haven't seen any mention of any unusual vehicle movements around the plant.
There is an outside chance Panasonic is making the 20700 cells in Japan, but in reality the new cells probably won't go into production until the battery fab line at the GF is up and running.
As for whether the 20700s could be used in the existing Model S/X design, I'm sure that was a consideration when designing the cell geometry. I think it may also be possible there are plans on using the same battery modules on the 3 and the S/X, just using more modules on the S/X. The layout of the modules in an S/X battery pack would likely be a bit different, but as long as the outside dimensions of the pack were the same or close enough to fit in the same space, it would work.
As for Tesla sitting on some battery tech that would take the battery size to 150 KWh or something, that's highly unlikely. There are no big secrets in the battery tech business. There are a few chemistries that are a little better than what Tesla is using now, but the current 90 KWh pack is about 95% of the max energy for a battery capable of production today. There are some experimental chemistries in labs right now that may push the capacity up around 120 KWh, but that's 2-5 years out and the testing isn't complete yet. These chemistries may prove to be too fragile for long term use in an EV.
The tech tweaking Li-ion battery chemistry is very similar to how Edison's lab did the light bulb. They are trying every material that might work in every mixture they can think of and seeing what happens. The number of variables is so vast and the nitty gritty of how the materials interact with each other is so unknown there are no computer simulations someone could sit down and tune up a chemistry. It's all trial and error. The cutting edge isn't so much in predicting chemistries, but in how fast labs can cook up prototypes to test.
There is an outside chance Panasonic is making the 20700 cells in Japan, but in reality the new cells probably won't go into production until the battery fab line at the GF is up and running.
As for whether the 20700s could be used in the existing Model S/X design, I'm sure that was a consideration when designing the cell geometry. I think it may also be possible there are plans on using the same battery modules on the 3 and the S/X, just using more modules on the S/X. The layout of the modules in an S/X battery pack would likely be a bit different, but as long as the outside dimensions of the pack were the same or close enough to fit in the same space, it would work.
As for Tesla sitting on some battery tech that would take the battery size to 150 KWh or something, that's highly unlikely. There are no big secrets in the battery tech business. There are a few chemistries that are a little better than what Tesla is using now, but the current 90 KWh pack is about 95% of the max energy for a battery capable of production today. There are some experimental chemistries in labs right now that may push the capacity up around 120 KWh, but that's 2-5 years out and the testing isn't complete yet. These chemistries may prove to be too fragile for long term use in an EV.
The tech tweaking Li-ion battery chemistry is very similar to how Edison's lab did the light bulb. They are trying every material that might work in every mixture they can think of and seeing what happens. The number of variables is so vast and the nitty gritty of how the materials interact with each other is so unknown there are no computer simulations someone could sit down and tune up a chemistry. It's all trial and error. The cutting edge isn't so much in predicting chemistries, but in how fast labs can cook up prototypes to test.
Johan
Ex got M3 in the divorce, waiting for EU Model Y!
I agree with your post for the most part. But the last paragraph is it bit off: the process of improving chemistry and formulation of the battery cells is not mostly a random/stochastic process (like biological evolution for example) but a very elaborate process with a lot of theoretical work, computer simulations and thought guiding the choice of what prototype to "cook up next". What I mean is a big well funded lab just trying a high volume of chemistries in a more random fashion would have to be very, very lucky to beat a smaller lab with more limited resources but with more brilliant researchers.
There is science that goes into narrowing down the choices to a select set of materials. I don't think anyone is testing lithium-oatmeal batteries. But once the likely materials are decided on, the ratios and whatnot are a hit and miss thing.
Contrast this with an integrated circuit maker. There are a number of chemistries that go into semi-conductor designs, but at this point, the chemistry is well understood. A transistor is made by interfacing two layers of N semiconductors with a P type in the middle, or vice versa. N semiconductor material is made by mixing (called doping) a tiny bit of material from the next column on the periodic table from Silicon and P material is made by mixing in a tiny bit from the column on the other side. This makes one more likely to give up an electron and another more likely to be looking to accept one.
The amount of impurity mixed in is on the order of parts per thousand down to parts per billion. For some applications a base material other than silicon is used. Germanium is one, and there are some compounds used too. If you are an engineer tasked with making a new semiconductor device, you can look up exactly the right chemistry for the application you have. For example transistors being used for an electronic switching application like in any digital electronics you want the material doped so the device switches over from one mode to the other as quickly as possible (from a 0 to 1 to a computer scientist) within the noise limits of your application (the quicker the transition the more noise can be generated by the switching), but if you want an analog application like an audio amplifier, you want different characteristics to the transistors.
All of these factors are known and there are computer simulations where you can test everything out before you ever etch a chip.
Battery tech is a different ball game. The exact way the ingredients mix is not fully understood. An engineer working on this stuff can eliminate a lot of materials because they are too expensive, too dangerous, too rare, or it's obvious they aren't suitable. For example, using plutonium in a battery would probably be a bad idea, even if the chemistry worked well.
In a similar way with making transistors a tiny change in the chemistry can have a big effect on the eventual product, but it's much harder to predict with batteries than with semiconductors. There are fewer variables you need to weigh in semiconductor design, the list of potential materials used in doping semiconductors is a lot shorter, and we have 50 years experience with all these materials. There are some exotic semiconductor formulations in the labs, and some of them may be approaching battery chemistry complexity, but there isn't a dying need for them so development is at a more laid back pace. Battery chemistry is the huge bottleneck in EV development.
Anyway, yes battery labs aren't completely shooting in the dark, but there is a lot more trial and error involved than most other areas of engineering tech development.
Johan
Ex got M3 in the divorce, waiting for EU Model Y!
So in general we are in agreement
Maybe not just as to the exact ratio of random experimentation vs. very well considered experiments. Thanks for your thoughtful post which was an interesting read.
This is because this field is still theoretically week i.e. new.
In the following years chemists will develop better understanding and models explain processes and in return it will be possible to engineer "the best" chemistry.
Yes, it will take some time.
Someone please test the capacity of a Lithium-Oatmeal battery.....
deonb
Active Member
Hey, that's what my ex-wife used to have for breakfast!
Life lesson: When someone says they're "bi", it is important to follow that up with a clarifying question.
Johan
Ex got M3 in the divorce, waiting for EU Model Y!
HankLloydRight
No Roads
The fastest way for Tesla to do something is for me to say it's not going to happen.
Therefore, I don't think Tesla will release a 100kWh battery pack for the Model S this calendar year. Although possibly it could happen for the Model X.
There, I said it.
Therefore, I don't think Tesla will release a 100kWh battery pack for the Model S this calendar year. Although possibly it could happen for the Model X.
There, I said it.
Reeler
Decade of Pure EV Driving
Just using larger diameter cylindrical cells will allow higher energy density. With each cell holding more and less dead space between them, the new cells will mean larger batteries. Anyone know what that would translate to? I am anxious to see these new larger ones later this year when production begins at the Gigafactory.
Are you sure about that?
Remember that the outside geometry of the battery pack remains fixed (since the new battery pack has to be physically interchangeable with the original).
The problem is then basically reduced to circle packing in a rectangle, which is not much different from circle packing in a square:
Circle packing in a square - Wikipedia, the free encyclopedia
If each cell in the battery pack has the same diameter, then I am very doubtful that you can increase the energy density. It looks to me as increasing the cell diameter will reduce the number of dead spaces, but increase the area of each, for no change in the density.
Production cost per unit energy can very likely be reduced, and while important, that is different.
Packing cells of different diameters would allow for higher density, but their use would be more difficult to manage.
I remember Elon saying something about 33% size increase worked out as a maximum, or sweet spot, in some simulation. And that was the reason why they would want to increase the cell size. But I can't remember, or he just didn't say, what they actually simulated. Maybe it has something to do with electrolyte/cathode/anode surface area, facing the ion/electron traveling direction, vs overall volume, but it could also have something to do with packaging simulations.
Both would make some sense, for packaging they could have run simulations as to which size of cell would fit their pack best, although I am not sure if they already knew their future Model 3 pack size and that should have some impact. It could also be that it really applies to the volume and size of each cell. Thermal and electrical resistance, could be factors here. I guess if you have a very wide but low cell, you could store less energy, but push more power in and out, while a high, but narrow cell, could store more energy, but you would have trouble handling lots of power. Then you end up with some geometry factor, a ratio of hight versus diameter, but not the physical size, which could be limited by thermal resistance, if the cell gets too wide, as well as the hight of the pack.
Maybe someone could find out what Elon meant with those comments, I am just speculating based on bad memory...
If they could effectively make cells that were square or rectangular instead of round, that would greatly improve the utilization of space, but I believe Tesla also uses the space between the cells for coolant. Keeping the batteries in the same temperature range as much as possible is an important factor in managing the life of the battery.
If the cells were the same diameter, but a little longer and they could fit that into the existing pack by making the modules a little bit taller, that would increase the energy density. It may also be more efficient to pack the new cells on their sides rather than vertically as they are now. It depends on the dimensions of the modules and the pack itself.
If the cells were the same diameter, but a little longer and they could fit that into the existing pack by making the modules a little bit taller, that would increase the energy density. It may also be more efficient to pack the new cells on their sides rather than vertically as they are now. It depends on the dimensions of the modules and the pack itself.
Johan
Ex got M3 in the divorce, waiting for EU Model Y!
Note: this doesn't at all mean all 70 cars are unlockable 75 cars. I think it means they ran out of 70 packs before all 70 orders that were locked in had been built, and this is the solution.
Like the 40-60 situation back in 2012 (but in that case the 40 pack never existed in the first place).
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