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DaveD
EVs Kick Gas!
For comparison, #181's standard charge range is currently ~221 ideal miles. It's been stable at that value for many weeks, if not a few months.
The last time I range charged (and took pictures of the VDS) was on October 11, 2016 -- it showed a range of 337 ideal miles. That was for a trip from Whistler, BC to Redmond, WA (home). VDS pictures show that at the conclusion, Trip: 234.7 mi, Net Energy: 54.66 kWh, Energy/mi: 233 Wh/mi, with 87 ideal miles range remaining.
The last time I range charged (and took pictures of the VDS) was on October 11, 2016 -- it showed a range of 337 ideal miles. That was for a trip from Whistler, BC to Redmond, WA (home). VDS pictures show that at the conclusion, Trip: 234.7 mi, Net Energy: 54.66 kWh, Energy/mi: 233 Wh/mi, with 87 ideal miles range remaining.
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I was wondering earlier: Does anyone know if Tesla buys the 3.0 cells in to order or did they buy a massive consignment a year ago and they are all sitting around aging somewhere?
dhrivnak
Active Member
My guess if they did a bulk purchase (likely in my opinion) they have the cells at half charge in cool storage. From my reading the shelf life is indefinite at those conditions. It is heat and the charge/discharge cycles that age the batteries.
Canuck
Well-Known Member
I thought Panasonic was making the batteries as fast as Tesla was ordering them, and at some points it was hard to keep up with production, which at least partially necessitated the battery giga factory. So I'd be surprised if Tesla had many batteries in storage for any significant length of time.
The Roadster 3.0 cells are different from the Model S (or original Roadster) cells. They're from LG Chem, not Panasonic. As far as I know, Roadster 3.0 is the only LG cells that Tesla uses, so it's at least conceivable that they ordered the whole thing in one batch and just kept them around.
That said, I'm pretty confident that Tesla knows how to handle battery cells, so it's probably not a huge deal, at least for a few years.
Canuck
Well-Known Member
Interesting, thanks, and so much for my theory. So if they're made by LG there might not be silicon in the cells, unless LG also experimented with silicon?
The cells use NMC chemistry similar to what is in the Bolt, Volt etc- no silicon
From what I heard, the packs are hand built in Palo Alto (not fremont) but could be wrong on that
In an earlier thread (or maybe it was earlier in this one), I recall that these cells are similar to others, but nobody has reported the exact cells being used in any other automotive application.
What is the consequence of not having any silicon? I'm so confused with all the different variations on Li-Ion batteries out there.
Based on a number of posts 3.0 are HG2 LG cells. I do not know for certain if that is the case. If it is, then
LG HG2 cells are NMC (lithium nickel manganese cobalt oxide) positive electrode vs small percentage silicon in graphite as the negative electrode. Most EV cells in the past (and many in the present) are graphite negative electrodes. Silicon containing graphite negatives are more "next gen", or more accurately, "present gen" cells. Silicon boots the capacity as it alloys with lithium.
LG HG2 cells are NMC (lithium nickel manganese cobalt oxide) positive electrode vs small percentage silicon in graphite as the negative electrode. Most EV cells in the past (and many in the present) are graphite negative electrodes. Silicon containing graphite negatives are more "next gen", or more accurately, "present gen" cells. Silicon boots the capacity as it alloys with lithium.
While silicon in the anode helps with capacity, the problem with it has historically been longevity. The cell degrades faster. It has been an active research area for a long time to try to overcome this problem. Supposedly the new gigafactory cells have some silicon in them, but afaik this was only confirmed by an off hand comment Elon made during a conference call or investor meeting once.
DaveD
EVs Kick Gas!
Tesla is in a research relationship with Jeff Dahn and his battery-research group at Dalhousie University to increase battery lifetime. Dahn is working specifically with NMC cells, and has been reporting good progress in increasing lifetimes, and has claimed that Tesla is using his research results in cell production at the Gigafactory.
Tesla battery researcher unveils new chemistry to increase lifecycle at high voltage
Tesla battery researcher says they doubled lifetime of batteries in Tesla’s products 4 years ahead of time [Updated]
Tesla battery researcher unveils new chemistry to increase lifecycle at high voltage
Tesla battery researcher says they doubled lifetime of batteries in Tesla’s products 4 years ahead of time [Updated]
Most of the research where degradation occurs is related to huge amount of research on 100% silicon nanocomposites which drastically improve the energy density of the cell. The game now is to use a negative electrode which contains mostly graphite as has been used in traditional Li-ion batteries with a small amount 5-15% of SiOx or silicon composite in the negative electrode. A small, but significant jump in energy density occurs because of this, and much better cycling than silicon composites, but maybe slightly less than pure graphite. I haven't seen true long really term calendar life data on the cells yet, simply because they haven't been around that long. As you note, will be interesting what Tesla decides to use in the 3. At least they have some of their own data coming from the roadster 3.0s, if indeed these are LG HG2 cells. Dahn is about the best you can get for research into improving lifetime of Li-ion in the academic world. This , combined with the partnership with Panasonic were very smart calls by Telsa.
JRP3
Hyperactive Member
It certainly is, there is really no comparison between the voltage curves of Cobalt based cells and FePO4 based cells. LiCo derivatives have a much steeper voltage curve and it's much easier to relate SOC and voltage with them than LiFePO4.
Has anyone kept going with the range charges to see if it improves things?
My car's CAC was on ~205.6 when I drove it home from the upgrade last week, down to 204.64 at the weekend and now after a range mode charge and drive to work this morning it is back to 205.68.
My car's CAC was on ~205.6 when I drove it home from the upgrade last week, down to 204.64 at the weekend and now after a range mode charge and drive to work this morning it is back to 205.68.
dhrivnak
Active Member
My CAC on my 1,5 battery can vary by one and a half points throughout the year. So you are likely looking at random noise.
I really doubt it. It seems pretty consistent that range mode charges increase the CAC on 3.0 batteries. While I haven't computed statistics on it to get a p-value to see if it's really significant, it sure feels like it is when I eyeball it.
If anyone wants to contribute more data, please let me know.
Did another range mode charge at work yesterday, let it balance for 40 minutes and then drove approx 80 miles home via a friend's place. The balance grid was all 0's while still plugged in before I left.
After I got home the CAC was down slightly, at 205.65 vs 205.68 before.
After I got home the CAC was down slightly, at 205.65 vs 205.68 before.
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