Anyone else surprised that new battery pack is only 90kwh?

[brianman]

70-90-110.

That would be great, but what is your source of information to back up your assertion?

I don't have a source and I'm definitely not asserting it, but that was my conclusion a few days ago as well.

It will be fun to have the charging conversations ...

Q: What kind of range do you get?
A: I dunno yet. The EPA is slow. Probably 350 miles.
Q: Hm, ok. How much energy does it store?
A: 110 kWh.
Q: Wait? What? It only puts out 110 kW of power? The horsepower is only like ...
A: No, it puts out over 700 hp -- over 500 kW.
Q: Wow. What are you charging it with at night?
A: 110V outlet.
Q: Wait I thought you said it was 110 kWh? I was asking about charging.
A: Yah, I charge the 110 kWh battery on 110V.
...
A: 3rd base.

 

[stopcrazypp]

I read somewhere, that cells are for Samsung but it seem to be only a guess. My idea of why I am holding this debate is that there is no problem with battery producers. If for example VW switches to 18650, they can have right now state of the art cells even without Panasonic.

And yes, you are right with the SoC estimations. I found my old measurement of NCR18650B and they can do ~2900mAh betveen 4,1-2,5V which is close to 90%. In previous post I get this messed with another type of cells. Sorry for that.

They can probably get the same capacity, but it'll probably be tough to find cells that can output 6C at the same time. The E-tron only outputs 340kW so that is 3.77C.
Also with lower volume, the price they get will likely be far worse. The e-tron R8 is $250k, the regular R8 is $116k, so that gives a pretty large price spread to fit the pack in.

So I don't think your implication that it'll be easy for other automakers to match the Tesla/Panasonic cells (keeping in mind all metrics from energy, power, price, etc.) with other suppliers is correct.

 

[dpodoll]

Is it possible that the 70 is the old 60 with new battery formula (same number of cells, etc) and the 90 is the old 85 with new battery chemistry? Maybe they are still offering the 85 until they use up all their old batteries, at which time it will be 70 or 90.

 

[Electricfan]

Is it possible that the 70 is the old 60 with new battery formula (same number of cells, etc) and the 90 is the old 85 with new battery chemistry? Maybe they are still offering the 85 until they use up all their old batteries, at which time it will be 70 or 90.

No, I don't think so, because when I recently bought my 85S I asked about this. I was considering the 70 - it was new. They assured me the chemistry was the same between the 70 and 85. Of course, they could have lied. Or I might have been talking to someone who didn't have a clue. But I would think any change in chemistry would be announced, even if as casually as they did with the 90.

 

[Pajda]

They can probably get the same capacity, but it'll probably be tough to find cells that can output 6C at the same time. The E-tron only outputs 340kW so that is 3.77C.
Also with lower volume, the price they get will likely be far worse. The e-tron R8 is $250k, the regular R8 is $116k, so that gives a pretty large price spread to fit the pack in.

So I don't think your implication that it'll be easy for other automakers to match the Tesla/Panasonic cells (keeping in mind all metrics from energy, power, price, etc.) with other suppliers is correct.

Yes, but implicate two aditional issues. 1) The powertrain of R8 e-tron was designed before the switch to 18650. So it is possible that their cells can do 6C as well. 2) Is there really a demand for 6C high-capacity cells in BEV mass market? The R8 is a supersport and the 4C seems enough for Audi. By the way I was very surprised how positively the "insane" and "ludicrous" acceleration was adopted by the Tesla customers.

So i still belive that there is no problem in 18650 knowhow. VW can build equivalent to Tesla Gigafactory only as a "design practice project". The real problem is that most BEV makers still hope that they will get "big" pouch cells (>20Ah) with equivalent energy density and price to 18650. So their eyes are now upon LG an their announced 2016 battery "miracle".

 

[Johan]

Yes, but implicate two aditional issues. 1) The powertrain of R8 e-tron was designed before the switch to 18650. So it is possible that their cells can do 6C as well. 2) Is there really a demand for 6C high-capacity cells in BEV mass market? The R8 is a supersport and the 4C seems enough for Audi. By the way I was very surprised how positively the "insane" and "ludicrous" acceleration was adopted by the Tesla customers.

So i still belive that there is no problem in 18650 knowhow. VW can build equivalent to Tesla Gigafactory only as a "design practice project". The real problem is that most BEV makers still hope that they will get "big" pouch cells (>20Ah) with equivalent energy density and price to 18650. So their eyes are now upon LG an their announced 2016 battery "miracle".

Why would a bigger cell be better, if it has the equivalent energy density and price as an 18650 cell? (I'm assuming of course that by price you mean $/Wh and not $/cell since the latter would mean the batteries were a lot cheaper).

 

[Pajda]

Why would a bigger cell be better, if it has the equivalent energy density and price as an 18650 cell? (I'm assuming of course that by price you mean $/Wh and not $/cell since the latter would mean the batteries were a lot cheaper).

Yes this is one of two fundamental questions in BEV world which I try to find an answer. The second one is why these bigger cells still have significantly lower specific energy than 18650 cell format. The best 18650 is now between 700-730Wh/l but big pouch cells have only 400-450Wh/l with the same chemistry. Maybe LG show us some breakthrough next year which was already announced. Otherwise from my point of view it does not make much sense to use other cell format than 18650. (or 20700 like the announced new one from Tesla).

 

[Johan]

Yes this is one of two fundamental questions in BEV world which I try to find an answer. The second one is why these bigger cells still have significantly lower specific energy than 18650 cell format. The best 18650 is now between 700-730Wh/l but big pouch cells have only 400-450Wh/l with the same chemistry. Maybe LG show us some breakthrough next year which was already announced. Otherwise from my point of view it does not make much sense to use other cell format than 18650. (or 20700 like the announced new one from Tesla).

Here's my view:

All other things equal (chemistry) smaller individually fused cells are safer and when individual cells go bad, depending on serial/parallel configuration, it's possible to lose less of total pack capacity.

Smaller cells may lead to more "non anode/cathode/electrolyte material" (i.e. packaging) which weighs. However smaller cells may have more optimal anode/cathode to electrolyte ratio (both surface and volume wise) than a larger cell.

JB has said they would like to increase volume by about 30% and that would be more optimal. This is basically the 20x700 mm cell. The 18650 was designed with smaller applications in mind (laptops and whatnot).

I keep thinking does anyone really know something clever about these basic concepts (size/volume/packaging) that Tesla wouldn't know? I don't think so...

 

[stopcrazypp]

Why would a bigger cell be better, if it has the equivalent energy density and price as an 18650 cell? (I'm assuming of course that by price you mean $/Wh and not $/cell since the latter would mean the batteries were a lot cheaper).

It's a combination of familiarity and less cell packaging overhead.

All of the battery packs conventional automakers deal with (from starter batteries to the ones use in hybrids) are made up of large format calls (usually prismatics also). Their engineers have a lot of familiarity with them, so they would be most comfortable using that format.

In terms of cell packaging overhead, the large format prismatic allows you to neatly package the cells close to each other, and larger cells means there is less enclosure surface area per given active material volume. So theoretically it should have higher energy density than small format cylindrical.

However, reality doesn't pan out this way because the large format prismatic format is less tolerant of battery chemistries with lower thermal stability (like high energy cells Tesla uses). This is because the same packaging overhead advantage mentioned above also reduces the amount of heat dissipation surface area, and reduces the ability to isolate cell defects (there is more energy per cell and less enclosure material per unit of energy). That is why the highest energy cells are not made in large format prismatic, thus 18650s still by far remain the energy density king.

The main reason why VW is even considering 18650s is because Martin Eberhard (one of the founders of Tesla) convinced them to seriously consider building packs using them during his stay at VW (he has since left).
http://www.teslamotorsclub.com/show...er-Martin-Eberhard-working-for-Volkswagen-ERL

 

[lagann]

I know, that in theory, more range is better, however I see little complaining from people that own 85s that they need more range than they have. Believe Tesla has hit the sweet spot here on a Range vs Cost vs weight.

Not sure an 95 pack would have much more value to actual owners than the released 90.

Believe forum people might just want bigger numbers to feel like winning something, however in the real world, the range of current Tesla cars is pretty acceptable.

I even hear from many owners of 60s that say for their needs, that is sufficient.

Kinda same with better 0-60 times. Everybody wants it, but few need it.

I wouldn't complain, but I have had very many times where I wanted to go visit a friend after work or similar circumstances which would involve me getting home with very very little charge. This also prevents me from feeling free to drive wherever when I am visiting her. I would have gladly gotten a 90 instead of an 85, and a 95 would be even better. That little bit of extra could make the difference for me.

 

[seclinton]

Yes this is one of two fundamental questions in BEV world which I try to find an answer. The second one is why these bigger cells still have significantly lower specific energy than 18650 cell format. The best 18650 is now between 700-730Wh/l but big pouch cells have only 400-450Wh/l with the same chemistry. Maybe LG show us some breakthrough next year which was already announced. Otherwise from my point of view it does not make much sense to use other cell format than 18650. (or 20700 like the announced new one from Tesla).

I think it does pay to understand the details a bit more

Larger format automotive batteries for example Johnson Controls VL6P and VL41M were cylindrical 6Ah and 41Ah cells. Now while the wound coil is something like 9-15feet long for both, the difference in capacity comes from using different thickness electrodes with the same chemistry. The coating on the electrodes carriers the battery capacity. As the coating gets thicker, the internal resistance of the cell increases, making high rate discharges less efficient. Thus the 6Ah cell would be used for a performance battery, while a 41Ah cell would be used mainly for range. Think Tesla vs. Leaf in pairing the motors.

The thinnest electrodes are either prismatic or small cylindrical. Cylindrical cells have better energy distribution and don't suffer from the same edge effects and current distribution across the electrode as prismatic.

Let's give Tesla credit for using the 18650 format and making a 7000+ cell system reliable and controllable.

As for Si anodes, the problem is brittleness. Si wells by a factor of 4-8 more than traditional graphite during Li Intercalation. That's why you see doped anodes with SiO, not pure SiO. Figuring out the right mix of C/SiO or thickness/Si is the next golden leap in battery. Anode technology has been and is still pretty stagnant.

 

[Pajda]

Here's my view:

JB has said they would like to increase volume by about 30% and that would be more optimal. This is basically the 20x700 mm cell. The 18650 was designed with smaller applications in mind (laptops and whatnot).

Yes this is interesting. If you look at volumetric and gravimetric energy density of the best available cylindrical cells you can see, that 12,6Wh 18650 with ~725Wh/l makes a narrow peak. Best smaller 18500 cell size are at ~524Wh/l(Panasonic). The same result you can see with 26650 cell size with ~525Wh/l. Other bigger or smaller cylindrical cell format are always even worse. For example above mentioned big cylindrical cell 144Wh Saft VL41M (NCA chemistry) have only 285Wh/l.

So my idea is that 18650 is already an optimal size. The main benefit for Tesla to continue with 20700 is that 30% lower cell count significantly improves the reliability and cost of their battery module assembly. The specific energy of 20700 will be at best the same (I suppose a little worse) than 18650 otherwise consumer electronic will already switch for it. But specific energy is not a problem for Model 3.

- - - Updated - - -

It's a combination of familiarity and less cell packaging overhead.

All of the battery packs conventional automakers deal with (from starter batteries to the ones use in hybrids) are made up of large format calls (usually prismatics also). Their engineers have a lot of familiarity with them, so they would be most comfortable using that format.

Yes I heard this explanation before and like it very much. It sounds me like "Our engineers have a lot of familiarity with steam engine, so why should we make trouble with the transition to a gasoline engine." :smile:

- - - Updated - - -

The main reason why VW is even considering 18650s is because Martin Eberhard (one of the founders of Tesla) convinced them to seriously consider building packs using them during his stay at VW (he has since left).
http://www.teslamotorsclub.com/show...er-Martin-Eberhard-working-for-Volkswagen-ERL

From my point of view is the main reason that there is still just no other cell technology that can even go close to 18650 in term of specific energy. But if in the whole VW concern only one person pointed out this, then yes Martin Eberhard is this guy. Otherwise we can say if Audi did not want to be R8 e-tron for a laugh they simply had no other choice. Besides, this corresponds to the fact that the transition to 18650 at VW took place very quietly.

 

[stopcrazypp]

From my point of view is the main reason that there is still just no other cell technology that can even go close to 18650 in term of specific energy. But if in the whole VW concern only one person pointed out this, then yes Martin Eberhard is this guy. Otherwise we can say if Audi did not want to be R8 e-tron for a laugh they simply had no other choice. Besides, this corresponds to the fact that the transition to 18650 at VW took place very quietly.

The etron R8 was under development for a long time using other battery tech. VW didn't even consider 18650s until Eberhard introduced it. He obviously is not the only person to work on it, but I don't think it is a stretch to consider him as the first person to point it out. He was the one to lead VW into building their first 18650 based pack for an electric Golf. In the end, VW didn't go with 18650s for the e-Golf, but I think it is obvious the use of 18650s in the R8 was transferred from the work Eberhard did.

 

[flyeyes]

I know, that in theory, more range is better, however I see little complaining from people that own 85s that they need more range than they have. Believe Tesla has hit the sweet spot here on a Range vs Cost vs weight.

Not sure an 95 pack would have much more value to actual owners than the released 90.

Believe forum people might just want bigger numbers to feel like winning something, however in the real world, the range of current Tesla cars is pretty acceptable.

I even hear from many owners of 60s that say for their needs, that is sufficient.

Kinda same with better 0-60 times. Everybody wants it, but few need it.

All true with respect to range, but only if you live in one of the places where the supercharger network is built out. Where I live in "flyover country," long or even medium road trips are essentially impossible. A 350 mile range would allow me to reach superchargers in three directions, currently I can barely reach one as of last month. I've made three day trips of 130 miles or so each way in the last three weeks, and making another next week. Not possible in an 85kWh Tesla. I made what would have been a 700 road mile each way, 5-day road trip two weeks ago. Not possible from here in a Tesla. 310 miles to the nearest supercharger in that direction.

I've got two children in college, one is a little over 300 miles away, happens to be in the only direction there is a supercharger so that's doable. The other is 160 niles, but no SC. Not happening.