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Very nice talk. To me the interesting points were cathode and anode are inherently stable just interaction with electrolyte gives degradation, higher state of charge and higher temperature were main culprits of harmful electrolyte interaction. Combinations of additives to electrolyte can give orders of magnitude better longevity.
You should mention to him that Tesla makes the Model S out of aluminum, so you don't have too many concerns about rust!
deonb
Active Member
One thing I'd like to know - does the rate of charge (0.5C vs. 1C vs 1.5C etc.) have any impact on the cell life?
JakeP
S P4996 ==> P02547
This thread is an incredible wealth of information. Thanks 100thMonkey for sending and sharing that letter. I am definitely dropping my charge limit to 70% instead of 80% where I normally let it sit...and I am really wondering how bad it was that I supercharged at Macedonia at 10 degrees F or so, when I didn't have to! Hopefully Tesla has some safeguards that we don't know about.
Thumper
Active Member
Thanks DJP and 100th! This is just the info we have all been looking for. Finally some informed guidance on optimal charging strategies! Thanks again.
deonb
Active Member
We know about it. The car will heat up the battery to above freezing before it starts charging it. You'll notice if you plug in with a cold battery on a cold day, it won't add any mileage for a few minutes while the battery is warming up.
Pretty sure Tesla's electronics take care of this one, as per their own patent:
LOW TEMPERATURE FAST CHARGE - Patent application
and
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.htm&r=23&p=1&f=G&l=50&d=PTXT&S1=tesla.ASNM.&OS=an/tesla&RS=AN/tesla
"fast charging at low temperature can, depending upon cell chemistry, result in lithium-plating inside the battery cell. Lithium-plating typically results in an irreversible capacity loss". Their patent describes "apparatus and method for fast charge preparation of low temperature cells potentially at risk of damage from fast charging." and allows "charge under a wider range of temperature conditions, and to prepare low temperature battery cells for fast charging."
Yes, the battery heating system targets 10C (50F). Besides, a lot of heat is generated during Supercharging which will bring the temp up on its own.
The unusual pronunciation and incorrect spelling of "Fiskar" was troubling as well.
I supercharged in Mishawaka at -2 F after an overnight cold soak. The battery first warmed for several minutes, then charge power slowly increased to 30 kW and stayed there for the remainder of the charge. This is for a 60 kWh battery.
Very interesting and informative. And it reminds of an article on LiIon batteries in a German computer magazine 15 years ago. It mentioned the exact same two top tings that are bad for LiIon cells: high temperatures and high state of charge. The basic knowledge was there, but it never became mainstream.
JakeP
S P4996 ==> P02547
Ok great, perhaps that explains why it took me 30 mins to get 120 miles on a B battery...the first few minutes were warming?
OK, I sent off another letter today, hopefully we get a response!
"Jeff, if you have a chance, I have a few more follow up questions. I do very much appreciate your time answering my questions!
Since they are both cobalt based would the consumer care recommendations (store at lowish SOC, Lowish temperatures, tending to mid voltage cycling) for LiCo02 cells be the same as a LiNiCoAi02 or a LiCoAi02 cell?
Also, does the rate of charge (0.5C vs. 1C vs 1.5C etc.) have any impact on the cell life?
have you tested NCA cells like the Panasonic NCR18650A and NCR18650B and would their care characteristics be the same.
Nicad is less and less common in consumer electronics but is still used and I have several gadgets that have them. I have been treating these pretty much the same (store at lowish SOC, Lowish temperatures, tending to mid voltage cycling) accept every so often I do a complete discharge and full charge to reduce the tendency toward memory effect. In your opinion, is this on track? anything to add?
In general, I am amazed at how few of devices/chargers have any sort of BMS other than avoiding runaway combustion. It would make so much sense for every one of these devices to have a long life mode, where they could be left plugged in but only charge to about 50%. so many of these devices end up plugged in all the time, and it dramatically cuts down their shelf life. please consider explicitly recommending this in your research if appropriate. To many phones, computers etc are thrown away because the battery only lasted a year or two, when, if treated better, could have lasted 5-10 years. by applying this care regimen, peak performance of many products can be vastly extended. I've gotten 5 years out of an iphone, 5+ years out of a cordless shaver and long life out of many other products. This has required a lot of careful charging... it would be so much easier if I could set the SOC limit on each device based on my needs, such as at home near a charger vs traveling where I need max charge. we need someone like you to push the industry to make this kind of thing a standard! (no pressure :~). Tesla with it's slider option has nailed this. some way to adjust the end charge limit should be on all consumer products. a SOC meter that showed red at both ends, with green in the middle, would help this be more intuitive for consumers, who now simply think fully charged is the best, which simply leads to killing the battery prematurely.
OH and as an aside, the Tesla S is aluminum, so no need to worry about rusting :~) and the AC induction motor is brushless with the only contacts points being two bearing sets... potentially, this car should last a very long time!
Again, thanks so much for your time!"
"Jeff, if you have a chance, I have a few more follow up questions. I do very much appreciate your time answering my questions!
Since they are both cobalt based would the consumer care recommendations (store at lowish SOC, Lowish temperatures, tending to mid voltage cycling) for LiCo02 cells be the same as a LiNiCoAi02 or a LiCoAi02 cell?
Also, does the rate of charge (0.5C vs. 1C vs 1.5C etc.) have any impact on the cell life?
have you tested NCA cells like the Panasonic NCR18650A and NCR18650B and would their care characteristics be the same.
Nicad is less and less common in consumer electronics but is still used and I have several gadgets that have them. I have been treating these pretty much the same (store at lowish SOC, Lowish temperatures, tending to mid voltage cycling) accept every so often I do a complete discharge and full charge to reduce the tendency toward memory effect. In your opinion, is this on track? anything to add?
In general, I am amazed at how few of devices/chargers have any sort of BMS other than avoiding runaway combustion. It would make so much sense for every one of these devices to have a long life mode, where they could be left plugged in but only charge to about 50%. so many of these devices end up plugged in all the time, and it dramatically cuts down their shelf life. please consider explicitly recommending this in your research if appropriate. To many phones, computers etc are thrown away because the battery only lasted a year or two, when, if treated better, could have lasted 5-10 years. by applying this care regimen, peak performance of many products can be vastly extended. I've gotten 5 years out of an iphone, 5+ years out of a cordless shaver and long life out of many other products. This has required a lot of careful charging... it would be so much easier if I could set the SOC limit on each device based on my needs, such as at home near a charger vs traveling where I need max charge. we need someone like you to push the industry to make this kind of thing a standard! (no pressure :~). Tesla with it's slider option has nailed this. some way to adjust the end charge limit should be on all consumer products. a SOC meter that showed red at both ends, with green in the middle, would help this be more intuitive for consumers, who now simply think fully charged is the best, which simply leads to killing the battery prematurely.
OH and as an aside, the Tesla S is aluminum, so no need to worry about rusting :~) and the AC induction motor is brushless with the only contacts points being two bearing sets... potentially, this car should last a very long time!
Again, thanks so much for your time!"
Gerardf
Active Member
Very interesting presentation and thread, thanks !
The more I learned about li-ion technology, the more angry I am getting at notebook manufacturers who more-or-less force users to charge to 100% in hot notebooks and also do not assist in preventing discharging to zero.
Even my small company has purchased quite many (expensive) Dell accupacks as they needed replacement every 2 years. This could have easily been prevented by smart software in the bios. Some investigatuon shows that some notebook manufacturers do now offer this. I think Dell has lost my future business, unless they quickly fix this. I will pay attention to this from now on.
Same goes for other equipment, think of the Apple products with hard to replace accu's. As we saw in the presentation accu's can have a very, very long usefull lifespann. I am getting the impression manufacturers actually prefer accus to fail to sell more accus and newer products. Not only a big waste. This has also given EV's a big extra hurdle to overcome.
The more I learned about li-ion technology, the more angry I am getting at notebook manufacturers who more-or-less force users to charge to 100% in hot notebooks and also do not assist in preventing discharging to zero.
Even my small company has purchased quite many (expensive) Dell accupacks as they needed replacement every 2 years. This could have easily been prevented by smart software in the bios. Some investigatuon shows that some notebook manufacturers do now offer this. I think Dell has lost my future business, unless they quickly fix this. I will pay attention to this from now on.
Same goes for other equipment, think of the Apple products with hard to replace accu's. As we saw in the presentation accu's can have a very, very long usefull lifespann. I am getting the impression manufacturers actually prefer accus to fail to sell more accus and newer products. Not only a big waste. This has also given EV's a big extra hurdle to overcome.
Mario Kadastik
Active Member
About the only other manufacturer with decent battery recommendations page I have ever seen is Apple. Too bad they don't enforce it more in their energy settings and software level.
Apple - Batteries
Apple - Batteries
gocken2
Model S: P6931
My wife and I both use Sony Vaio ultra-book / laptop. Both of these computers are set to charge the battery to 80%.
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