I do not agree only with this statement, because using SiO additives is already well known technique and it is now widely used by major cell producers like Samsung and LG. These producers always had the 18650 equivalents to the Panasonic cells and they already have it even for the new 12,6Wh cells.
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I do not agree only with this statement, because using SiO additives is already well known technique and it is now widely used by major cell producers like Samsung and LG. These producers always had the 18650 equivalents to the Panasonic cells and they already have it even for the new 12,6Wh cells.
stopcrazypp
Well-Known Member
Can you point out some example cell models from those companies then (high capacity and partial silicon anode)? Panasonic 3400mAh NCR18650B had been out since early 2012. 3600mAh NCR18650G out in mid 2014. 3400mAh NCR18650BF with the partial silicon anode had been out since late 2014.
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Obviously it depends on your perspective. There are many ways to chart the development of the batteries and specific energy is but one metric. Given about 240-250 Wh/kg, ability to discharge at almost 5 C, the NCA cells that Tesla used in 2012 were state of the art. Further, Tesla probably paid somewhere around $250/kWh for them. Developments in battery technology are clearly non-linear. Since then, the costs have dropped to where the cells are probably in the $160-180/kWh. The packs can tolerate higher discharge rates and went from basically 1C for Supercharging to 1.75C for Supercharging. And now, we get a specific energy bump of 6%.
In many ways, the range is sufficient in my mind if it is possibly to charge at a higher rate. I'd take the ability to charge at 2C (180 kW) over another 5% bump in range.
Johan
Ex got M3 in the divorce, waiting for EU Model Y!
While I've been sceptic to the idea until recently, I've now come around and begun warming up to the idea of a top-of-the-line Model X with a battery bigger than 90kWh.
Yes, equivalent to
Panasonic (NCA) NCR18650A, 11,2Wh (2009) was LG (LCO) ICR18650D1, 11,2Wh (2009),
Panasonic (NCA) NCR18650B, 12Wh (2012) was LG (LCO) ICR18650E1, 12Wh (2012),
These cells have graphide/carbon anode only
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Sanyo (NCA+SiO/C) NCR18650GA, 12,6Wh (2015) is LG (NCA+SiO?/C) INR18650 MJ1, 12,6Wh (2015) and Samsung INR18650-35E, 12,6Wh (NCA+SiO?/C) (2015)
I do not know exactly if all of these 12,6Wh uses SiO but it is most probably, because LG already uses SiO in their smartphone batteries from 2012!. You can also find LG patents about using SiO dated from 2012 as well. I have also made some measurements and the new LG and Samsung 12,6 Wh cells have nearly two times lower internal resistance than its predecessors. Also 3C continuous discharge is not a problem for these cells. It was impossible to do it with an old NCR18650B unless you do not want to bake it.
I am still waiting for NCR18650GA to compare...
If the discharge/charging rates (C) for the 90kW pack will be that dramatically different, it's quite possible Tesla could decrease the supercharging time for cars with these packs. It's a shame Tesla doesn't disclose this fact, although given recent learnings with autopilot etc discussing a feature that has not yet shipped may be a bad idea.
I wouldn't pay 10k for another 5kWh over an 85 (I don't think), but 5kWh and decreased supercharging time, maybe. Of course that means finding a stall with a pair that isn't already in use. Yeah, now that I'm typing this I realize it's too complicated for most. Tesla will eventually do this, but they'll chalk it up to "a benefit for the entire tesla community" by decreasing demand on the network.
I wouldn't pay 10k for another 5kWh over an 85 (I don't think), but 5kWh and decreased supercharging time, maybe. Of course that means finding a stall with a pair that isn't already in use. Yeah, now that I'm typing this I realize it's too complicated for most. Tesla will eventually do this, but they'll chalk it up to "a benefit for the entire tesla community" by decreasing demand on the network.
From what we've seen of the cables inside the cars, what we know of the superchargers themselves, etc... it's not likely that we'll see much additional peak power delivered via a supercharger. As such I'm not sure the overall C-rate will be much different, and verly likely not "dramatically" as you mention..
What would be interesting is if the charge taper is modified as a result of the new cells... that might be one way to reduce the overall time as you propose...
I based my comments on an article specifically about Tesla's 90 kWh pack. Per that article, Tesla is the only company that appears to have cracked this puzzle and put some Si into its anodes. I'm not an engineer and I don't work for Samsung or have first hand knowledge of what they are doing, I am only reporting what I've read.
stopcrazypp
Well-Known Member
Those Panasonic cells operate at a standard 3.6V nominal and 4.2V charging voltage (which Tesla actually limits lower for battery degradation reasons). The LG cells operate at 3.75V nominal and 4.35V charging voltage (they have lower mAh, 3000mAh and 3200mAh respectively). I didn't find any cycle life graphs, but I suspect the LG cells will be much worse than the NCA cells from Panasonic if they have to operate at high voltage to get their rated capacity.
The other issue is that even though the Panasonic NCR18650B cells aren't power optimized, they have a peak discharge of 6.8A (2C) and pulse discharge of 12A (3.5C). The LG cells peak at ~5A (1.5C) from what I can find.
Sanyo is owned by Panasonic, so they are one and the same. As for the LG and Samsung, as I suspected, the SiO hasn't been used in high capacity 18650 until now, so Panasonic is still the first in that regard. Also, the cells Tesla specified can pulse discharge at ~6C (to get the 515kW suitable for ludicrous mode from a 90kWh battery) and capacity is probably closer to 13Wh (3.6V*3.6Ah), not just 12.6Wh.
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That would be great, but what is your source of information to back up your assertion?
Yes Panasonic NCA are 3,6V nominal with 4,2V top charging voltage (it is standard top charging voltage for NCA chemistry). Tesla do not limit top charging voltage. You can see pictures from superchargers with ~403-404V which equals to 4,2V per cell. Tesla only limits that you cannot discharge full capacity of cells down to 2,5V.
I really admire Panasonic battery research, but I think that if LG or Samsung will be asked, they can handle this as well. Yes Panasonic 18650 cells are the best for automotive, because they have great sales for them. LG is still focusing mainly on consumer electronics so even their 18650 cells are designed for it. By the way LG already producing SiO high-powered 18650 cells http://www.powerstream.com/p/LG 18650HE2 Technical Information.pdf and I assume that new 12,6Wh LG NCA cells are using SiO as well (because there are not many possibilities to do it without using SiO) but right now I do not have confirmation for it.
The Panasonic 4.0ah silicon annode cells are 13.6wh
Green Car Congress: Panasonic Develops New Higher-Capacity 18650 Li-Ion Cells; Application of Silicon-based Alloy in Anode
stopcrazypp
Well-Known Member
I reference to this which indicates 4.19V for both 85kWh (402V/96) and 60kWh (352V/84). Perhaps it does do 403V at end of taper, then it will be 4.2V.
http://www.teslamotorsclub.com/show...ces-S60-S85-and-P85/page3?p=445256#post445256
Yes, I know LG has had high power SiO 18650s for a while, but Panasonic is the one that made high energy SiO 18650s first in 2014 (that are also high power at the same time). In the 18650 market, if you are looking for standard 4.2V charging voltage, Panasonic is the king in terms of high energy, and LG/Samsung is just catching up now. It is the combination of high energy and power which is why Tesla is continually going with Panasonic. I believe Tesla was negotiating with Samsung about a supplier contract, but I think their tech is just catching up now to be able to supply it.
There is no evidence that these cells ever leave a production plant, otherwise we will now get the 95kWh battery.
I really insist on 4,2V per cell :smile: Supercharging Tesla Model S 85 kWh to 100 % - YouTube Yes you are right, that lowering the tapering voltage will result in great improvement of cycle life, but NCA and LCO chemistry are also very sensitive on top charging voltage value in the term of usable capacity. So if you lower it to 4,19V you can use only 92-95% of capacity. Tapering at 4,1V gives you only 80% percent of full capacity.
Yes you are right that Panasonic is actually leader in developing 18650 cells for automotive industry, but LG is leader in the same technology used in pouch (li-pol) cells. So they both most probably have equivalent knowhow but they are focusing on different markets which have another requirements. And now we can see that LG is catching up Panasonic even in 18650. By the way do you have idea who is the 18650 cell supplier for new ~90,2kWh battery of Audi R8 e-tron?
Interestingly, although the 4.0Ah cell in that table has higher volumetric energy density than the 3.4Ah cell, it's lower in mass energy density.
Of course, that's a 2009 page, so things could certainly have changed since then.
stopcrazypp
Well-Known Member
For the Roadster, Tesla limited voltage to 4.15V, which they say is 95% SOC. So I imagine if they really used 4.19V, it would be higher SOC than that.
http://www.teslamotors.com/blog/bit-about-batteries
I concede given the video evidence that it is 4.2V.
The etron uses 7488 of them (52 modules of 144 cells). 90.2kWh implies 12Wh cells, which they can get from pretty much anyone. I have no idea who is the actual supplier.
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.
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