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Discussion Starter · #1 ·
Following the release of the "D", I was surprised that the "something else" wasn't a larger pack.

This could hint that Tesla may make more significant increases less often than a small change more frequently.

The super charger network is making range possible and practical for those willing to add 1hr for every 150-200 miles driven.

Once you get to 300 miles "easy" range most people (excluding hardcore long range drivers) would be ready for a break anyway.

I doubt we'll see a 95-100kWh pack, instead we'll get a much larger jump - perhaps 125-165kWh range.

What are your predictions?
 

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I'm going to guess the next major change will be when the gigafactory is up and running. Probably see tweaks to the battery chemistry and density at that point.

Based on Bjorn's youtube video's replacing the battery pack isn't too much of an issue, so hopefully retrofitting better packs in the future would be possible.
 

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There will be an upgrade, either when the X or the 3 is released. I suspect it will be when the 3 is released. Roughly speaking I expect the 3 to ship with a ~60kwh and ~80kwh battery, and the S gets 85 as standard and ~110 as a new size. The S needs to remain the "top dog".
 
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The talk coming from Tesla re: gigafactory is of improvements in cost efficiency/economies of scale rather than any step change in density tech, so I'm personally not expecting any major announcements for at least 3 years as suspect focus of the company will need to be elsewhere (ie. ramping up production to meet shareholders expectations).

What I think will be interesting - and this is my prediction - is that we will see tesla beginning to reposition li-ion battery tech/the gigafactory facility (where they will increasing have a major competitive edge over trad automakers) as more central to strategy. Media/analysts havnt yet 'got' the significance of elec power storage, where as tech improves and costs reduce, huge markets will emerge both on-grid (ie. the energy suppliers) and off-grid (businesses, domestic customers) for standlone facilities that enable you to fill up on cheap (off peak) electricity and then use during peak periods. I believe this is why there is such a huge disconnect between the amount of battery capacity tesla could ever use in the vehicles it sells (or supplies other ev makers) and the capacity of the nevada facility.

I also predict that in next 12 months we will hear Elon Musk talking up the future possibility of tesla vehicle owners being able to sell (maybe via special feed in tariff) spare Kw capacity back into the grid at preferential 'real time' rate negotiated (and managed) by tesla on behalf of its customers. Energy companies have a real hard time servicing unforseen spikes in demand, and would pay a premium for scalable instantaneous feed-in capacity. Imagine getting into your tesla and having a 'sell %age spare capacity into network at 100p/kwhr' slider control on the touchscreen. Or just being able to configure your tesla's battery's spare capacity to run your household elec whenever its outside during daytime/evening instead of paying normal peak rate KWhr charges. EV owners have big, efficient, storage capacity on their driveway. Someone sometime soon is going to start thinking about ways to make it do more than just power the car alarm.
 

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V2G (vehicle to grid) needs to be more than just a vehicle that is able to feed back in. Although I can see the vendors benefits to the grid, not so sure I am happy to get back to a half empty battery because of aggressive use by my utility company!

Tesla have been talking about a large (30% iirc) reduction in battery packaging for model 3. If that approach can be applied to the S then that opens up the possibility of a 110 battery, but, I personally think a 30% lighter 85 battery would be more beneficial than a much heavier 110 battery.
 

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Panasonic already have a 3.7Ah cell, the S uses a 3.1Ah cell, so there's an obvious upgrade to ~101kwh for the same volume as the 85kwh pack. Once they start using their new format cell it's easy to see that better packaging getting 101 up to 110 in the same volume.
 

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Someone sometime soon is going to start thinking about ways to make it do more than just power the car alarm.

What like charging up at an Ecotricity point, then selling it back to them for a massive profit ? ;) I could give up my day job :p

V2G (vehicle to grid) needs to be more than just a vehicle that is able to feed back in. Although I can see the vendors benefits to the grid, not so sure I am happy to get back to a half empty battery because of aggressive use by my utility company!

Tesla have been talking about a large (30% iirc) reduction in battery packaging for model 3. If that approach can be applied to the S then that opens up the possibility of a 110 battery, but, I personally think a 30% lighter 85 battery would be more beneficial than a much heavier 110 battery.
I think that the packaging reduction figure will be achieved by moving away from 18650 cells. Whether they go for flat lithium without heavy metal casings.

Better tessellation of the cells, would allow them to fit the same number of cells into the same sized square box. Whether or not the individual cell is 30% lighter I'm slightly sceptical if they use the same chemistry.

Another option is they could also use larger cells, and have fewer of them, reducing the need for all that wiring and soldering.

When Tesla was a start-up trying to get the best bang for their buck 18650s made perfect sense. If they are in control of their own battery production, they'd probably go for something more bespoke for their needs.

But I agree a lighter model S with the same kWh would be great, both from a performance, handling and range POV!




 

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What like charging up at an Ecotricity point, then selling it back to them for a massive profit ? ;) I could give up my day job :p



I think that the packaging reduction figure will be achieved by moving away from 18650 cells. Whether they go for flat lithium without heavy metal casings.

Better tessellation of the cells, would allow them to fit the same number of cells into the same sized square box. Whether or not the individual cell is 30% lighter I'm slightly sceptical if they use the same chemistry.

Another option is they could also use larger cells, and have fewer of them, reducing the need for all that wiring and soldering.

When Tesla was a start-up trying to get the best bang for their buck 18650s made perfect sense. If they are in control of their own battery production, they'd probably go for something more bespoke for their needs.

But I agree a lighter model S with the same kWh would be great, both from a performance, handling and range POV!



Yes the new format will still be cylindrical but a larger diameter. Flat cells present different problems!
 

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I also predict that in next 12 months we will hear Elon Musk talking up the future possibility of tesla vehicle owners being able to sell (maybe via special feed in tariff) spare Kw capacity back into the grid at preferential 'real time' rate negotiated (and managed) by tesla on behalf of its customers..
Thinking a little more about this a little more. (And being less flippant about reselling electricity you've obtained for free). Wouldn't Tesla have to deduct your Supercharger usage from your net feed in?

I've always wondered how Tesla would eventually monetise the Supercharger network. This would be a neat way.

So you can sell back electricity to Tesla (who are just a billing agent in this case) at £x per kWh, who sell it back to the grid at £x+, but because you obtained it for "free" at a Supercharger they will want to reclaim costs at £y, which will inevitably be higher than the wholesale rate they are paying, effectively making a cut on both ends of the deal.

Of course the "free Supercharging for life" depends on your POV. I see it as a mandatory option on the 85, especially as it depreciates at 57% not 50% like the rest of the car. Over 3 years, if you sell the car you have paid £1000+ in depreciation... That's a heck of a lot of electricity ;)


Besides battery swap technology actually makes more sense at demand smoothing ;) Charge even more batteries at night and swap them during the day when the grid is under the most strain.

Makes much more sense than filling at a high current Supercharger during the day, and maybe trickling it off back to the grid in the evening.
 

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Vehicle to Grid is a great concept and I think Tesla is going to stay away for now. The rash of issues they've dealt with in various poor wiring in houses just increases risk, something that they need to avoid for now. I think they're going to let Nissan tackle the thorny issues first as they have many more pressing issues to tackle.

Also, I mentioned in the other thread about form factor issues. The primary reason why we don't see a bigger battery pack right now is the weight, not size. Until they are ready to tweak the battery chemistry, I doubt we will see a bigger battery pack. Also, one can argue that we are roughly within the boundaries of a reasonable battery size at 85kWh. At this point, it might be more beneficial to increase charging C-rate rather than obtain a bigger battery. That way the charging taper curve could be less pronounced.
 

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I doubt we'll see a 95-100kWh pack, instead we'll get a much larger jump - perhaps 125-165kWh range.
What are your predictions?
@PMC Paul,
I think the next battery size will be either 100 or 105 kWh. There are two data points we can use to estimate next battery capacity:

1. JB said (*) 10 to 15% improvement in energy density due to improved chemistry. If we take the optimistic number 15%, that would be 1.15*85= 97.75 kWh.

2. Elon said (*) we are at 300 Wh/kg. In 2012 they were at 240 Wh/kg. That is 25% improvement. This would mean 85*1.25= 106.25 kWh.

I think there are two realistic scenarios for the next batteries.

Option 1) 70/75 & 100 kWh (both the 60 and 85 are upgraded)
Option 2) 85 & 105/110 kWh (85 remains and new battery is added)

Originally the battery sizes were 40, 60 and 85 kWh. From 40 to 60 that was 20 kWh too. Therefore 85&105 seems acceptable. Of course 110 kWh would be even better but I don't see it happening in 2016 and Gigafactory will start production in 2016 and those cells will be used for Model S/X. Here is the source:

On 7 Nov 2014, Tesla 10-Q Securities and Exchange Commission report had the following information: Source (Page 26)


Quote: Construction continued during the third quarter of 2014 at an accelerated pace with first cells expected to be produced in 2016 for use in Model S and Model X. We plan to use the battery packs manufactured at the Gigafactory for our vehicles, initially for Model S and Model X, and later for our Model 3 vehicle, and stationary storage applications.

What would be really impressive is if they also manage to reduce the weight of the car. I think Tesla wants to do that. They have been reducing weight constantly here and there. So I think a 100 or 105 kWh Model S that weighs slightly less than the S85 would be really impressive. I would expect Option 1 to happen in 2015 before Model X launch. If that doesn't happen, I would expect Option 2 to happen in late 2016 with the Gigafactory launch. I keep going back and forth between these two options. Both are likely. Currently I think option 2 in 2016 is slightly more likely because in a recent email Tesla said the X will use S85D platform. This implies they have been doing tests on that platform and they are happy with the results.

The talk coming from Tesla re: gigafactory is of improvements in cost efficiency/economies of scale rather than any step change in density tech, so I'm personally not expecting any major announcements for at least 3 years
@alan denyer,
Tesla has confirmed the cells made at the Gigafactory will have an improved chemistry. JB said 10-15% better. The following transcript is from 31 July 2014 Tesla conference call with the media. Source (When you open it for the first time it will ask you for login details. You can enter any bogus info you want)

25:23 Journalist: On the Gigafactory, is the chemistry going to be the same battery chemistry that you're currently using or is that part of the discussions that are going on with Panasonic?
25:34 Elon Musk: There are improvements to the chemistry, as well as improvements to the geometry of the cell. So we would expect to see an energy density improvement and of course a significant cost improvement. JB, do you want to add anything?
25:53 JB Straubel: Yeah, that's right. The cathode and anode materials themselves are next generation. We're seeing improvements in the maybe 10% to 15% range on the chemistry itself.
26:09 Elon Musk:Yeah, in terms of energy density.
26:09 JB Straubel: Energy density. And then we're also customizing the cell shape and size to further improve the cost efficiency of the cell and our packaging efficiency.
26:22 Elon Musk: Right. We've done a lot of modeling trying to figure out what's the optimal cell size. And it's really not much. It's not a lot different from where we are right now but we're sort of in the roughly 10% more diameter, maybe 10% more height. But then the cubic function effectively ends up being just from a geometry standpoint probably a third more energy for the cell or maybe 30%. And then the actual energy density per unit mass increases.
27:09 JB Straubel: Yeah. Fundamentally the chemistry of what's inside is what really defines the cost position. It's often debated what shape and size, but at this point we're developing basically what we feel is the optimum shape and size for the best cost efficiency for an automotive cell.
27:25 Elon Musk:Yeah.
27:28 Journalist: The chemical formula will be the same, it's just shaped differently or?
27:32 Elon Musk: No.
27:32 JB Straubel:No.
27:35 Journalist: Is it a different formula?
27:37 Elon Musk: Yeah.

Of course improving the cells could mean keeping the same capacity and reducing number of cells on the Model S from 7104 to a lower number. The result would be a new 85 kWh battery that weighs less. This would improve range because of weight loss and it would also help against tire wear. However I think Tesla can do both. Upgrade the battery and reduce the weight at the same time. Tesla wants to succeed in Germany and the limited range in autobahn speeds is not very impressive. Also in Feb 2014 in Oslo. Elon said "There is potential for bigger battery packs in the future but it will probably be maybe next year or something like that." 7:10s: LINK. I recommend reading the following topic I linked below. It contains links to all information we have so far.

(*) source is available in the opening message of this topic.
 

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Discussion Starter · #13 ·
I interpreted that differently. At a cell basis:-

85kWh + 10% improvement in chemistry = 93.5kWh
93.5kWh + 30% improvement in energy density = 121.5kWh​

Assuming the whole pack can also be optimised, I'd say a 125kWh pack that is the same size as the current 85kWh one is possible.

In fact, I would imagine that Tesla have prototypes around this size already and large scale production of them might not wait until 2016!

Tesla is still in a tough position. All the big manufacturers are starting to take notice and raise their game on the EV front, and most of them have more money to throw at it. However, they still seem to be happy to be playing "we can do that too" instead of "whatever you can do, we can do better".

From a commercial perspective, when Ford/Audi/Whoever actually look like they have a 300 mile EV entering production, Tesla (Elon Musk) will "reveal" that "300 miles was so yesterday - here's our new 125 pack which gives a theoretical 450 mile range" (360 miles equiv of our current real world 250).

I hope existing owners would get the option of a pack upgrade and it being a high-end "P125D" option on new cars in mid-late 2015. Perhaps becoming a more standard level option/configuration in 2016/17 when the factory is in production.

I would be very surprised if Elon / Tesla doesn't have very high goals for the "top end" models (S and the X). So by the time the Model 3 is in production, we would be having S and X with 500+ mile range.
 

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I think you misunderstood what Elon means by 30%. He says if you increase the height of an 18650 by 10% and the diameter by 10% as well, the volume of the cylinder increases by 30% from a pure geometry standpoint. An 18650 is 18mm in diameter and 65mm in height. We want to find out the volume of that. Here is a calculator. Enter 9 for radius and 65 for height. As you see the volume is 16,540 cubic millimeter. Now, if we increase the radius and height by 10% each that would be 9.9mm and 71.5mm and the volume is 22,015. The increase in volume is 22,015*100/16,540-100= 33% That's what Elon means.

The volume and the energy per cell increases 33% but the energy density doesn't increase. Then why are they changing the size? It is because it will be cheaper to make less cells that are slightly bigger. The Model S has 7104 cells. If energy per cell increases by 30% then they will need to make 5464 cells. Even from just a manufacturing time perspective it makes sense because the robots that are going to make these cells will take the same time whether it is 10% taller or not.

Another benefit will be simpler packaging. Currently the Model S battery pack has 7104 cells in 16 modules. The bump you see in this picture has two modules stacked on top of each other. With 10% taller cells they can get rid of the bump.



They have 16 modules and the cells are 65mm tall. The multiplier is 16*65= 1040. If they reduce the modules to 15 and increase cell height to 70mm the multiplier would be 15*70= 1050. As you can see the numbers work. They can achieve the same pack volume with 15 modules. The reason why this is a good thing is because each module has some electronics components. With 15 modules the pack will be cheaper because it is completely flat and requires simpler packaging and less electronics.

I agree with you that a new battery size is a possibility with the Model X launch in Sep 2015 but another strong possibility is Sep 2016 with the Gigafactory launch. Any time between those two doesn't seem possible because Model X owners who will take delivery in Sep 2015 would be pissed if a new battery was introduced just a few months after they get their car after waiting for years.

I also agree with you that Tesla wants to do something impressive. But I think 100 or 105 kWh that weights slightly less and doesn't cost much more than the current pack would be very impressive.
 

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Discussion Starter · #15 ·
Yes, but I am wondering if there is "spare" space in the pack (or where the pack fits in the car) so with the 30% increase in cell volume doesn't actually mean a 30% in pack size (or a slightly bigger pack will still fit in the car). And then add the density increase. As per Elon's reply:-

26:22 Elon Musk: Right. We've done a lot of modeling trying to figure out what's the optimal cell size. And it's really not much. It's not a lot different from where we are right now but we're sort of in the roughly 10% more diameter, maybe 10% more height. But then the cubic function effectively ends up being just from a geometry standpoint probably a third more energy for the cell or maybe 30%. And then the actual energy density per unit mass increases.
 

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Yes at the moment there's a (let's guess) 4mm gap between cells for the cooling pipes. If the cooling system doesn't need to be increased in size then that 4mm gap remains the same, but you have fewer cells so gain 4mm back for each cell you can remove. 7104 cells becomes 5338 cells, that's a big saving on packaging. Fill that space back up with with more cells is maybe 15% more capacity, improve the density is maybe another 15% on top of that. 85*1.15*1.15 is 112.5.
 

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I've always wondered how Tesla would eventually monetise the Supercharger network.
At the moment it is built into the selling price of the cars. £1800 option on the 60kw car or £2300 after delivery.

No reason why they couldn't someday offer contracts or PAYG to owners without lifetime supercharger access.
The PAYG price would be steep to match the lifetime pricing.
 

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I think the change in form factor has maybe 2% effect on energy density at cell level. They should have a further 3% improvement because they will get rid of the bump which saves some weight in packaging which they can fill in with more cells. So 5% improvement in energy density at pack level with the new form factor seems possible. If we add 15% chemistry improvement, that would be 85*1.05*1.015= 102.6 kWh

I think improving efficiency is as important as increasing battery size. An interesting number is range per kWh. The S60 has 208 miles EPA rating. That would be 208/60= 3.47 miles per kWh. The S85 has 265 miles EPA. That is 265/85= 3.12 miles per kWh. The reason why the S60 performs better is because it is lighter.

If they increase the capacity to 100 kWh and reduce weight, they could improve miles per kWh to 3.2. This means 320 EPA rating for S100. If they do this without changing the price, I think it would be super impressive.
 

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At the moment it is built into the selling price of the cars. £1800 option on the 60kw car or £2300 after delivery.

No reason why they couldn't someday offer contracts or PAYG to owners without lifetime supercharger access.
The PAYG price would be steep to match the lifetime pricing.
£100 for a 30 day activation?
 

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Option 1) 70/75 & 100 kWh (both the 60 and 85 are upgraded)
Option 2) 85 & 105/110 kWh (85 remains and new battery is added)
My wild guess is they will offer option 2.

Selling the 85 at the old 60 price and the 110/115 at the 85 price would follow the Apple sales model.

An Apple-like Option 3 60/85/110 with the 60 seeing a modest price reduction is less likely because Tesla prefer to simplify manufacturing.
 
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