So you basically agree that the promised advancement of battery tech just didn't pan out so far?
Essentially. Though Elon did say at some point that battery improvement is not a smooth curve. If you stand back and look at a long term trend it's around 6% a year, but it's in fits and starts.
On the 2nd point, that does seem plausible. They may have something awesome lined up, but needing scale to keep the costs in check.
On the 30% more efficient geometry I'd like to see a link
Predictions for new battery | Tesla Motors
From July 2014:
Tesla Conference Call:
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.
They mention 30%, but it's unclear if that's the actual improvement. Further down on the 24 Oct 2014 bit they talk about 10-15% better GF cells.
I've seen people doing the math (then still on 20x70mm vs 18x65mm, not 21x70 they seem to have landed on) where on paper the new cell takes up nearly 33% more space. But the relationship of the can to the contents changed (likely making the can as big as it can hold with the alloy sheet material in use now) only improved such that there is only 10% more energy per cm³.
I knew something was wrong, but had a brain fart.
If their new cooling solution takes up less space and allows 11% more of the 18650's to be crammed in an S/X pack (hoping this is achieved without changing orientation of the cells) also translates to the new 21-70 cells (you'd think it was even developed especially for 21-70), indeed a substantial update may be possible when those cells come out of GF1.
It's possible.
All potential gains combined from 100kWh pack we get "now":
+10% for switch to 21-70 cells (and resulting 110 pack would be lighter, a bit)
I expect the pack with the new cell geometry will also come with chemistry improvements which will yield more than 10% per cell, but the pack with the larger cells will probably have fewer cells per pack.
+7.7% in 100 pack has cells upright. And it's been reported 21-70 would fit upright as well
+? An overdue chemistry update, potentially making up for years of disappointing progress.
And while you want to keep things simple as possible, should Tesla merely decide a bigger revamp of the S/X cars and pack, they surely could make it bigger, one way or the other. Thicker seems relatively easy.
When Model S was designed, I suppose the pack didn't need to be larger, as the cells to fill it would cost an amount beyond the type of car they were building. Now that costs are falling thanks to scale, biggerpack can be made and found buyers for. A pack should not get in the way of the rest of the car, but surely a few cm can be added, even if that starts affecting air drag. I don't expect them to do any of this, though. In their place, I would seriously consider a limo version of the S. A foot longer wheelbase, bit taller, lots extra battery space. A significant car the competition would not be able to build. Increasing the battery, it remains a big part of the production cost, especially for others. It's then time for Mercedes and the like to say that so much range is not needed
Tesla is going to have to do something to distinguish the S from the 3. The S will have some features the 3 won't, most obviously the hatchback, but to further distinguish them they might give the S/X a much larger battery pack. That will also help relive congestion at superchargers. When the S/X gets to a point where the real world range is as far as people typically drive in a day, then the emphasis shifts to destination charging and S/X travelers won't be using superchargers.
