Tesla's Model 3 2170 cells=same energy desity as 18650's

[bonaire]

30% you say?

Could that mean a Model S pack bump from 100 kWh to...

[Unsubstantiated Rumor] Just Read That A 130 Battery Is Being Tested??!!

if they puff up the height of the pack, sure. Why not.
The reason for such a pack?
Trucks - whether Semi or consumer. A pickup truck would definitely need more capacity for similar range to a Model X. Rumors of that for a year+ now. Maybe we see it in a month.
One 130kWh pack would allow for delivery trucks in areas like LA and Manhattan. A larger truck with 260kWh would be useful for say the larger UPS and DHL style box trucks offering 200 miles+ range.

I would like to see eventuality of a pack like this go into the RV industry, though luxury Class-A units don't sell more than a few thousand per year (Newmar and similar).

 

[voip-ninja]

if they puff up the height of the pack, sure. Why not.
The reason for such a pack?
Trucks - whether Semi or consumer. A pickup truck would definitely need more capacity for similar range to a Model X. Rumors of that for a year+ now. Maybe we see it in a month.
One 130kWh pack would allow for delivery trucks in areas like LA and Manhattan. A larger truck with 260kWh would be useful for say the larger UPS and DHL style box trucks offering 200 miles+ range.

I would like to see eventuality of a pack like this go into the RV industry, though luxury Class-A units don't sell more than a few thousand per year (Newmar and similar).

It's almost definitely not cost effective to build a custom pack for an application like truck/semi when they could instead stack multiple packs they already mass manufacture together for that application.

 

[George S. Bower]

@George S. Bower - start here:

How much would you pay to uncork your Model S 75/75D?

Thx Apacheguy. I believe it. The silicone anodes may not be holding up :

WK057 quote:

"As for the 75s, my speculation is that they've returned to using a cell chemistry closer to that of the original 85s, as the 90/75 cells do not hold up on the longevity side as well as the 85-type chemistry."

PS and OT
My 2012 Model S #1682 will be coming off warranty in 3 years. Is there anyone -WK057 or otherwise- that will make some software mods to my car to get me a little faster 0-60 time?

 

[bonaire]

It's almost definitely not cost effective to build a custom pack for an application like truck/semi when they could instead stack multiple packs they already mass manufacture together for that application.

I would see it going into cars and other things. There are other reasons for larger packs in cars. Mainly for those who drive Uber, long commutes, don't want as many stops at superchargers, etc.

 

[AnxietyRanger]

It's almost definitely not cost effective to build a custom pack for an application like truck/semi when they could instead stack multiple packs they already mass manufacture together for that application.

Be that as it may, 18650's are the past. 2170's are the future. Tesla has already built a new 2170 pack for Model 3. What is the next "big pack" from Tesla, when 2170's replace the 18650's that Tesla's current big packs are made of?

What would be the equivalent of the current 100 kWh pack, similarly sized (a bit higher perhaps), but in 2170 terms... perhaps indeed it would be 130 kWh? And we might see it in current Model S/X and maybe in other applications as well...

 

[voip-ninja]

I would see it going into cars and other things. There are other reasons for larger packs in cars. Mainly for those who drive Uber, long commutes, don't want as many stops at superchargers, etc.

It comes down to what Tesla views as the optimal range for their cars at the high end.

I'm sure if they offered a Model S with a 400 mile range they would have buyers lined up... just maybe not enough to justify the millions that such a battery would cost to develop and manufacture.

 

[AnxietyRanger]

It comes down to what Tesla views as the optimal range for their cars at the high end.

Not just range, performance also. Think of the 0-60 a 130 kWh pack could produce...

I'm sure if they offered a Model S with a 400 mile range they would have buyers lined up... just maybe not enough to justify the millions that such a battery would cost to develop and manufacture.

But they will no doubt produce a new Model S/X pack based on the 2170 cells created for Model 3 and the Gigafactory. The 18650 are, as Elon Musk put it, an accident of history. They will be going away at some point.

The new Model S/X 2170 pack (let alone a truck pack) will most likely be larger than 100 kWh...

 

[R.S]

Not just range, performance also. Think of the 0-60 a 130 kWh pack could produce...

But they will no doubt produce a new Model S/X pack based on the 2170 cells created for Model 3 and the Gigafactory. The 18650 are, as Elon Musk put it, an accident of history. They will be going away at some point.

The new Model S/X 2170 pack (let alone a truck pack) will most likely be larger than 100 kWh...

The amount of kWh doesn't have to have an impact on the power output. Only if you increase the number of cells in a pack, you get to more power, but if you use more energy dense cells, power output could even be lower, even though energy goes up.

But I think we should see some improvements in energy density at some point. It's now 5 years since the Model S came out and even with an average improvement of 4% per year, a pack the size of a 100D should have over 110kWh. Not sure if the cell format has anything to do with it, though.

Generally I am pro 2170s in the Model S, but only because they should be cheaper and more mass market. But chemistry, not so much form factor improvements are needed to really improve the range of the Model S/X.

 

[AnxietyRanger]

The amount of kWh doesn't have to have an impact on the power output. Only if you increase the number of cells in a pack, you get to more power, but if you use more energy dense cells, power output could even be lower, even though energy goes up.

But I think we should see some improvements in energy density at some point. It's now 5 years since the Model S came out and even with an average improvement of 4% per year, a pack the size of a 100D should have over 110kWh. Not sure if the cell format has anything to do with it, though.

My logic goes that the 2170 form-factor allows fitting more cells in the same space or nearly the same space, because there is less in terms of packaging etc. in the way. The whole thread (and others like it) points to similar energy density, if not better. Also history: every since kWh upgrade by Tesla has improved performance as well.

Then there's Elon saying Tesla will stop at 100 kWh. I think that is true for the 18650's. However, I fully expect that story to eventually change with the 2170s...

Generally I am pro 2170s in the Model S, but only because they should be cheaper and more mass market. But chemistry, not so much form factor improvements are needed to really improve the range of the Model S/X.

I don't think being pro or against has much relevance. Obviously Model S/X will move to 2170s. The question is not if, it is when.

 

[bonaire]

The amount of kWh doesn't have to have an impact on the power output. Only if you increase the number of cells in a pack, you get to more power, but if you use more energy dense cells, power output could even be lower, even though energy goes up.

But I think we should see some improvements in energy density at some point. It's now 5 years since the Model S came out and even with an average improvement of 4% per year, a pack the size of a 100D should have over 110kWh. Not sure if the cell format has anything to do with it, though.

Generally I am pro 2170s in the Model S, but only because they should be cheaper and more mass market. But chemistry, not so much form factor improvements are needed to really improve the range of the Model S/X.

"improve the range". Actually - what is the range needed anyway? I find that most people don't drive batteries down from range-charge to empty daily. The range improvement is not a requirement for 90% of EV drivers out there, but rather it's an edge case. People driving the "little EVs" like the Leaf or Chevy Volt can drive daily with no problems. The vast majority now of Model S being sold are 75 sized batteries since the charging infrastructure is growing and people are most likely ok with the range.

The reason to increase range would be to install fewer batteries per-car so that the input parts diminish. We need ways to get more EV cars made, not more EV batteries used. We need to get people interested in buying more EVs with less batteries on board (for less $$) so that more people can get into EVs. The Model 3 may help do this, as do the others. Range then also gets affected by cold ambient conditions - this is where chemistry that withstands cold soaking and winter conditions works better. Many EV buyers get "surprised" in the winter of their first year as it is hardly ever now discussed during the sales cycle (and maybe avoided entirely for a reason).

 

[R.S]

Also history: every since kWh upgrade by Tesla has improved performance as well.

Ok, there are two different ways of increasing the energy in a pack, one is increasing the number of cells, the other is changing the cells to more energy dense ones. Now we only had one change to more energy dense ones before and while power also increased, one single instance isn't enough to make a rule for. Every first human being on any moon has be a Neil. Coincidence?

My logic goes that the 2170 form-factor allows fitting more cells in the same space or nearly the same space, because there is less in terms of packaging etc. in the way.

In the same volume? Actually there should be less energy per volume, since a larger form factor can't be packaged as efficiently. They could make the pack higher, though. IMO increasing the packs weight isn't really an option. We've already seen that the 100 kWh cars have payed in terms of safety rating, for their increased range. Making the car even heavier just doesn't sound like a good solution.

"improve the range". Actually - what is the range needed anyway? I find that most people don't drive batteries down from range-charge to empty daily. The range improvement is not a requirement for 90% of EV drivers out there, but rather it's an edge case. People driving the "little EVs" like the Leaf or Chevy Volt can drive daily with no problems. The vast majority now of Model S being sold are 75 sized batteries since the charging infrastructure is growing and people are most likely ok with the range.

The reason to increase range would be to install fewer batteries per-car so that the input parts diminish. We need ways to get more EV cars made, not more EV batteries used. We need to get people interested in buying more EVs with less batteries on board (for less $$) so that more people can get into EVs. The Model 3 may help do this, as do the others. Range then also gets affected by cold ambient conditions - this is where chemistry that withstands cold soaking and winter conditions works better. Many EV buyers get "surprised" in the winter of their first year as it is hardly ever now discussed during the sales cycle (and maybe avoided entirely for a reason).

The reason to increase the range would be installing fewer batteries per car? Also, I wasn't arguing for more range, I was just stating the fact that range increase needs to come through improved chemistry. If more range is needed is a totally different topic.

 

[AnxietyRanger]

n the same volume? Actually there should be less energy per volume, since a larger form factor can't be packaged as efficiently.

My theory is that it 2170s can actually be packaged more efficiently than 18650s - and that there is thus more chemistry in the pack and less packaging metal etc...

 

[Topher]

My theory is that it 2170s can actually be packaged more efficiently than 18650s

How so? Packing cylinder into rectangular boxes quickly asymptotes to about 90% efficiency.

Thank you kindly.

 

[AnxietyRanger]

How so? Packing cylinder into rectangular boxes quickly asymptotes to about 90% efficiency.

Thank you kindly.

It is my theory only. I am assuming Tesla created a more efficient design. 2170s wasting more space than 18650s doesn't seem like an end-result they'd be aiming for.

So the theory goes: larger cylinders means less cylinders needed (less metal etc. taking space) and also more vertical space used (larger/higher cylinders in that sense as well), so more kWh into the same space assuming similar chemistry...

I am assuming, well guessing really, Tesla optimized the cell size to such that they can interweave them and the necessary cooling more effciently.

Why would Tesla design a cell that would be less efficient to make a pack out of? The cost-only angle doesn't IMO fly, they have had to come to this cell size because it makes sense...

Also, as an added - but admittedly optimistic spice - let's not forget the 130 kWh rumor.

 

[BioSehnsucht]

Bigger cylinders = less cylinder "can" per unit of volume inside the cylinders. So even if the empty spaces outside the can don't improve much between adjacent cylinders, the ratio of useful volume to non-useful volume improves.

 

[R.S]

My theory is that it 2170s can actually be packaged more efficiently than 18650s - and that there is thus more chemistry in the pack and less packaging metal etc...

The bigger the cylinder the worse the packaging will be, so 18650s should be easier to package.

 

[AnxietyRanger]

The bigger the cylinder the worse the packaging will be, so 18650s should be easier to package.

I just find it hard to believe Tesla would have developed a harder to package cell...

Here is the logic I'm talking about - just found this, I had come to a similar conclusion personally:

Tesla's 21-70 Vs 18650 battery cooling principles. (possibly derpy analysis). • r/teslamotors

Considering the newer format batteries have a larger radius, this will mean they can be packed more closely together while maintaining a similar radius of curvature in the coolant lines. If this was the case the coolant lines would cover a larger area of each batteries circumference. Therefore the coolant will be able to more effectively cool the larger battery as it has a greater contact with the coolant lines. By having more effective cooling the batteries in each battery line can have a smaller distance between them. Consequently you can achieve a much higher packing fraction with larger radius batteries while maintaining adequate cooling. The higher packing fraction means there is less wasted space in the battery module, and thus you can squeeze more battery density into the same foot print.

 

[Topher]

wasting more space than 18650s doesn't seem like an end-result they'd be aiming for.

Of course it doesn't. Why would you think anyone would think that?

larger cylinders means less cylinders needed

Yup. So what?

more vertical space used

Agreed. Having an extra 5mm of height which was formerly unused, makes the increase from 65 to 70 hugely advantageous. On the other hand, making the battery taller, and THEN finding the extra volume in the vehicle will have engineering trade-offs.

Tesla optimized the cell size to such that they can interweave them and the necessary cooling more effciently.

Tesla optimized the cell size for SOME factor. We have no idea what that might be, but I can think of a couple dozen off the top of my head, any of which makes sense for some goal. But is there any optimizing of packing that they can even do? The WORST packing I could find for that many circles was within 1.3% of the theoretical MAXIMUM. There just isn't that much packing optimizing the could do.

Why would Tesla design a cell that would be less efficient to make a pack out of?

They wouldn't unless it had other redeeming qualities. Why would you ask that, no one has suggested that Tesla DIS-optimized their design.

let's not forget the 130 kWh rumor.

No, let's forget it. Someone just took the 30% improvement figure that has been flying around the net, and applied it to the P100D. No credibility.

Thank you kindly.

 

[AnxietyRanger]

A surprising amount of pushback for the idea that a 2170 battery pack could house more kWh in similar housing (e.g. in Model S) than 18650.

I guess I just don't see where that pushback is coming from, so have to just agree to disagree I guess.

Seems infinitely logical to me why it might. I have presented my reasoning. The density of the chemistry being assumed roughly equal, 2170s would waste less space for metal etc. if there is a need for less cells (less containers). So more chemistry in the same space, because there is less surrounding metal. Additionally speculation that this cell-size could be more optimal for interweaving cells and cooling...

I agree we don't know yet.

 

[stopcrazypp]

The bigger the cylinder the worse the packaging will be, so 18650s should be easier to package.

I just find it hard to believe Tesla would have developed a harder to package cell...

Here is the logic I'm talking about - just found this, I had come to a similar conclusion personally:

Tesla's 21-70 Vs 18650 battery cooling principles. (possibly derpy analysis). • r/teslamotors

Just geometrically, using the Model S module size as a baseline. Width: 11.9 Inches (302mm), Length: 26.2 Inches (666mm)
Tesla Model S Lithium Ion 18650 EV Module - 22.8 Volt, 5.3 kWh, EV West - Electric Vehicle Parts, Components, EVSE Charging Stations, Electric Car Conversion Kits

Using the triangular packing (there are customized packing algorithms more efficient, but just as an exercise).
Circles within a Rectangle

18650: 18mm diameter (254.47 square mm area), tightest similar rectangle (666x299mm) fits 694 circles, packing efficiency 88.685%
2170: 21mm diameter (346.36 square mm area), tightest similar rectangle (672x293mm) fits 504 circles, packing efficiency 88.659%

So 18650 would just be barely more efficient in packing if using all of the area.

Of course coolant lines have to be figured in (radius of curvature factor for example you quote), and also cooling efficiency (the 2170 would be slightly harder to cool per given volume of active material given less surface area per volume). Also cell wall thickness has to be factored in (this effects active material packing efficiency).

I believe the number one advantage of 2170 is that it is cheaper to manufacture. It may also have better Wh/kg or Wh/l, but we don't know the figures for that yet.