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Discussion Starter · #1 · (Edited)
My predictions are as follows:

New Battery Size: 105 kWh
Release Date: Aug 2016
EPA Range:
367 miles Model S105D
357 miles Model S105 & P105D
334 miles Model X105
300 miles Model S85D
290 miles Model S85 & P85D
272 miles Model X85

Let me explain how I came up with these numbers.

1. New Battery Sizes

The next gen battery size is mostly determined by yearly improvements in lithium ion battery technology. The idea is to replace existing cells with new cells and have more capacity without weight or price increase. There are skeptics who think lithium-ion batteries don't improve much or they improve very slowly. Therefore I want to give a few sources about this.

Marc Tarpenning is one of Tesla's co founders. They built the company on the idea that lithium-ion batteries improve constantly. In this presentation from 30:06 to 32:20 Tarpenning talks about battery improvements. If you switch to HD you can see a chart that shows 7.5% improvement per year. If we accept this percentage, year by year capacity improvements would be as follows:

2012: 85.00 kWh
2013: 91.38 kWh
2014: 98.23 kWh
2015: 105.60 kWh
2016: 113.51 kWh
2017: 122.03 kWh
2018: 131.18 kWh
2019: 141.02 kWh

Nov 2012. Elon Musk talked about yearly improvements to battery technology too. Watch from 40:00 to 40:45. LINK He said: ... lithium-ion batteries continue to improve. Roughly, on average, maybe 8% or 9% per year. Which, when compounded over several years, ends up being a meaningful improvement.

Feb 2014, Oslo. Elon said the following: "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.

May 2014. JB Straubel talked about this as well. Watch from 5:19 to 8:15 LINK He said:

6:50s "We looked at this graph and spent a lot of time talking to all the different companies driving the improvements here and there was nothing and still is nothing today that's clearly starting to plateau on this graph. These improvements are still compounding and improving and it's not a Moore's law, it's not close to that but it's something close to doubling in performance, of energy density performance about every 10 years."

7:29s "Model S was introduced about 5 years after the Roadster and we saw improvements around 40 percent. These improvements are not standing still. We are continuing to watch the same doubling every 10 years for at least another 10 to 20 years."

Jun 2014. Annual Shareholder Meeting. Elon said the following:
Elon Musk (3 Jun 2014): "You should expect to see a steady increase in range, the available range in the cars over time." (Source 1:06:31 to 1:07:28)

Jul 2014. Panasonic published a PDF file with the following information:

Quote: "Joint development with Tesla Motors is also presently underway for next-generation EV lithium-ion battery cells."

Source 1 (web page), Source 2 (PDF file page 51)

Then at the end of the same month on 31st July 2014, Tesla had a conference call with the media. This is what JB Straubel and Elon said:

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.

Source (When you open it for the first time it will ask you for login details. You can enter any bogus info you want like John Smith, info at example dot com.)

10 Oct 2014, SoCal Energy Summit. JB Straubel used the following image in his presentation.

24 Oct 2014. Elon Musk said "For a cell that doesn't have lots of other drawbacks we are at roughly 300 Wh/kg" 38m 05s: LINK. According this article from 27 Feb 2012 "Model S batteries should weigh in at around 240 Wh/kg" Source: LINK. In other words 1 kilogram of battery cells used to store 0.24 kWh energy but now it stores 0.3 kWh. This means the cells in the 85 kWh battery (not the pack itself but just the cells) weigh 85/0.24= 354kg. The new cells that have the same 354kg weight and 300Wh/kg energy density would have the capacity of 354*300= 106.2 kWh. Therefore I expect the new battery size to be 105 kWh.

2. EPA Range
Range per kWh for the Model S is a good criteria to look at.

60 kWh Model S has 208 miles EPA range. 208/60= 3.47 mi/kWh
85 kWh Model S has 265 miles EPA range. 265/85= 3.12 mi/kWh

However the EPA ratings haven't been updated since Jul 2012 when they were announced but the car has improved. The current Model S85 would receive higher EPA scores if it was tested today. I wrote about this in another topic here in case you want to read more. The current numbers should be as follows:

60 kWh Model S has 215 miles expected EPA range. 215/60= 3.58 mi/kWh
85 kWh Model S has 289 miles expected EPA range. 289/85= 3.40 mi/kWh

Why does the S85 have worse miles per kWh score than the S60? Because it is heavier. The reason it is heaver is because the battery has more cells. The next gen battery would have the same number of cells (7104 cells) as the S85 because we are replacing existing cells with new cells that weight the same. Therefore it would get 3.4 mi/kWh too.

3.4*105= 357 miles EPA range for S105. 367 miles EPA for S105D. In that topic you can also see that I estimated the S85D EPA rating to be 299 but now I expect Tesla to achieve 300 to get the extra ZEV credits.Model X is expected to have 91% range of dual motor Model S. That would be 0.91*367= 335 miles. S85 would be 0.91*299= 272. Putting all these together we get the list I wrote at the beginning of this message.

3. Release Date

Tesla will start losing money on ZEV credits in 2015 because they don't qualify for the maximum credit points per car. To get the maximum points they need to meet these two criteria:

1. 300 mile EPA rated range
2. Battery swap stations

These criteria are mentioned in section 1962.1(d)(5)(B) on page 13 in these regulations PDF LINK. At the end of page 13 and beginning of page 14 it says: "Examples of fast refueling events include ... swapping of the depleted battery". The 300 mile rule is valid for 2015, 2016 and 2017. This means Tesla doesn't want to delay upgrading the battery too much because they would lose money on ZEV credits. Therefore it would make sense to do the battery upgrade sooner than later even though there is no other car company challenging Tesla.

There is already construction work going on at Harris Ranch battery swap station: LINK1, LINK2. Gigafactory starts production in 2016 and it will make next gen cells which is now confirmed by both Panasonic and Tesla. Isn't 2016 a little too late for ZEV credits? It is but Tesla can do a soft upgrade to range without upgrading the battery. Improvements in power electronics and reduction in weight is likely to bring S85D EPA range to 300. The EPA range for S85D is not announced yet but it is expected soon. The new EPA range for S85 should also improve from 265 to 289. All this is consistent with latest range data available on the order page since 10 Oct 2014.

When the Gigafactory starts production, Tesla will continue importing cells from Japan. Then cells from both sources will be made into packs at the Gigafactory. This means next gen cells will come from Japan too. Technically it should be possible to switch to next gen cells before the Gigafactory. However releasing the 105 kWh early in 2016 is not a good time because Model X buyers would be upset if their car was outdated a few months after they received it after waiting for years. Therefore it makes sense to wait until the Gigafactory which I expect to start production in Aug 2016.

5 November 2014. Elon said Source

17:28: With respect to the cathode materials, there is a lot of technology improvements that we will be able to apply to the battery pack and the cathode, anode, separator, can production, the whole works. Some of these improvements are independent to others.

17:50: Whatever we build out for the Gigafactory has to work at least at the lab level, let's say this year because we are making monster investments in equipment and there is a certain amount of time, a year or two at least from working at the lab level to working at small scale production. Then at least a year or two after that you can go from small scale production to mass production.

To me this sounds like Elon is saying the new battery is ready now at lab level but they can't do mass production in 2015 because it needs more time.

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.

This means we know that the Gigafactory will make next gen cells and we also know it will start production in 2016 and additionally we know that those cells will be used in Model S and X. That is the reason for my 2016 prediction for the next gen battery pack.

450 Posts
Interesting and a very nice write up.

I wonder if Tesla consider the battery to be part of the "Model S Platform" or a serviceable / replaceable consumable.

After watching the battery swap video, and the comments about paying the difference between the pack you had and the new one, I wonder how likely it is that battery upgrades could be easily done. I'd probably be willing to pay the difference in a few years to upgrade to 125+ kWh. It could even be more cost effective than waiting for 5-10 years when the old one has deteriorated considerably.

200 Posts
Discussion Starter · #4 · (Edited)
@PMC Paul,

I think Tesla could offer an upgrade. We can do some calculations based on available data. There is an article here by a Model S owner who upgraded his battery from 60 kWh to 85kWh. A new 85 kWh price was $44,564 in Dec 2013. At the time Tesla paid Panasonic $250 per kWh (source). There is also packaging, electronics and profit margin included in the battery pack sale price. A likely break down is as follows:

21,250 for 85 kWh cells at $250/kWh
2,000 for packaging
4,000 for electronics
17,314 profit at 63.5% of cost price
Total: $44,564

Right now Tesla pays Panasonic $180/kWh (source). This price is expected to go down. If we assume $150/kWh for 2016 and drop the profit margin to 25%, a 100 kWh battery would cost:

15,000 for 100 kWh cells at $150/kWh
2,000 for packaging
4,000 for electronics
5,250 profit at 25% of cost price
Total: $26,250, £16,514

Trading in the existing battery should reduce the price further. The prices are expected to go below $100/kWh after the Gigafactory starts production in 2017. In an interview in Oct 2014 Jerome Guillen (Tesla Vice President of World Wide Sales and Service) said Elon set the target of the Gigafactory at 30% price reduction but cutting the costs by half should be possible (source).

2,746 Posts
The problem with this theory is that Tesla have not increased capacity for 3 years now. They also have not reduced the cell count in the pack. So no changes, no improvements etc.

One reason for this is limited supply. It is bound to make more commercial sense to sell two S60s rather than one S120.

Another reason is that improved (and proven) chemistry just isn't there.

You seem to have missed the comments made about the Model 3 battery in the Q2 earnings call.

JB discussed a different format cell - improving capacity by 10% iirc - and different packaging for the pack, which they felt would reduce the mass significantly.

This, IMO, will be the next generation of Tesla battery, and it is highly unlikely that we will see that before the Gigafactory comes online.
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