Nope. That was Dr. John Goodenough from UT Austin, who invented and pioneered the first Lion batteries, manufactured by Sony for commercial purposes
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Is Tesla making progress in improving battery energy density?
- Thread starter electracity
- Start date
Nope. That was Dr. John Goodenough from UT Austin, who invented and pioneered the first Lion batteries, manufactured by Sony for commercial purposes
SmartElectric
Active Member
Read my words again :
I didn't say he pioneered the battery chemistry itself, I said he helped pioneer the current state of the art, which is true. The guy is modest, but his work is critical to the current ability for cells to work with longevity and stability.
Jeff Dahn
Halifax battery researcher wins $1M Herzberg Medal
Jeff Dahn - Wikipedia
I didn't say he pioneered the battery chemistry itself, I said he helped pioneer the current state of the art, which is true. The guy is modest, but his work is critical to the current ability for cells to work with longevity and stability.
Jeff Dahn
Halifax battery researcher wins $1M Herzberg Medal
Jeff Dahn - Wikipedia
I'm happy to take your word for that. Personally, I lack the technical expertise to make that judgement. A lot of bogus arguments seem to make sense to someone unfamiliar with the field. In a case like this, I can believe he's legit and if I'm wrong, it won't affect me. But I would not make investment decisions based on a YouTube video. If it was really important to me, I'd research his credentials.
I was just curious as to the basic thrust of the video, and you guys have answered that for me, which I appreciate.
I watched this video some months ago and personally found it engaging. I'm not a battery researcher, but I had a decent science education (bachelor's degrees) and tend to be inquisitive. The idea that coulombic efficiency is predictive of battery lifespan seems to make a lot of sense. The more side reactions that take place, the greater the potential for degradation. Side reactions will tend to reduce coulombic efficiency.
just got done reading this whole thread and another on the dimensions of the new Roadster.
So the roadster may be a little shorter than the Model 3.
ggnyk's post here:Comparing new Roadster exterior dimensions to original Roadster
....but perhaps wider. Elon put the upper limit on how many cells you could fit in the Model 3 at around 80 kwh. If we double stack that gets us to 160 kwh.
In order to get to 200 we only need a 25% improvement in volumetric energy density. Where will it come from?
I'd like to add 1 more variable that I didn't see anyone mention in the comments......Cycle life
With 600 mile range that drastically lowers the required cycle count life required for the battery. According to battery university
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
one can push the DOD and fully charged voltage higher for fewer cycles required. Maybe a 10% gain in energy density just by pushing the DOD.
Plus we don't know how much Tesla has held in reserve on the new 2170 cells. Sure they look roughly the same in volumetric energy densty as the 18650's,
Tesla's Model 3 2170 cells=same energy desity as 18650's
but Tesla can just program that by lowering the charge voltage/DOD.
Double stacking will save some weight and volume as well. Also it's possible that a new TMS system could offer 5% or so.
So I'm holding out that the current 2170's can be made to work in the Roadster.
Then again Panasonic may already have a next gen cell in the testing phase that will give us another 10% or so. Ther's talk that LG and SK already have NMC 811 almost ready to release.
http://pushevs.com/2017/09/08/lg-chem-will-introduce-ncm-811-battery-cells-evs-next-year/
with almost 1 kwh/L energy density.
(2160's are .734 kwh/l) Tesla's Model 3 2170 cells=same energy desity as 18650's
Can Tesla do the Roadster w/ existing 2170 cells?? It's close. I guess we have to wait and see.
So the roadster may be a little shorter than the Model 3.
ggnyk's post here:Comparing new Roadster exterior dimensions to original Roadster
....but perhaps wider. Elon put the upper limit on how many cells you could fit in the Model 3 at around 80 kwh. If we double stack that gets us to 160 kwh.
In order to get to 200 we only need a 25% improvement in volumetric energy density. Where will it come from?
I'd like to add 1 more variable that I didn't see anyone mention in the comments......Cycle life
With 600 mile range that drastically lowers the required cycle count life required for the battery. According to battery university
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
one can push the DOD and fully charged voltage higher for fewer cycles required. Maybe a 10% gain in energy density just by pushing the DOD.
Plus we don't know how much Tesla has held in reserve on the new 2170 cells. Sure they look roughly the same in volumetric energy densty as the 18650's,
Tesla's Model 3 2170 cells=same energy desity as 18650's
but Tesla can just program that by lowering the charge voltage/DOD.
Double stacking will save some weight and volume as well. Also it's possible that a new TMS system could offer 5% or so.
So I'm holding out that the current 2170's can be made to work in the Roadster.
Then again Panasonic may already have a next gen cell in the testing phase that will give us another 10% or so. Ther's talk that LG and SK already have NMC 811 almost ready to release.
http://pushevs.com/2017/09/08/lg-chem-will-introduce-ncm-811-battery-cells-evs-next-year/
with almost 1 kwh/L energy density.
(2160's are .734 kwh/l) Tesla's Model 3 2170 cells=same energy desity as 18650's
Can Tesla do the Roadster w/ existing 2170 cells?? It's close. I guess we have to wait and see.
Brando
Active Member
If the chemistry is the same, so is the density - per liter. obvious, right?
But, the 2170 is what, about 30% improvement in volume? [or is it 47%??] then it follows that on battery pack energy density is higher because of the increased volume of the 2170 vs 18650. right?? size does matter in this case.
(not a direct relationship, but an improvement in volume efficiency - more density per pack size/volume. right?)
warning, I have not done any actual calculations - for example
10 kWh = number of 18650 compared to number of 2170 and
the "pack size" to contain these cells would be 18650>2170
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Brando
Active Member
So you are implying the "pack size" of 2170 batteries is larger than the equivalent 18650 battery pack?
color me confused - if true, why make the larger cell?? optimization just doesn't work with regards to cell size??
So we don't get a smaller "battery pack" - a more energy dense "battery pack"?
anyway, doesn't really matter, my confusion, no need to waste any more time trying to explain to me.
thanks for the info, jkn.
To address the first point, the 60kWh existed entirely for cost reasons and the maximum they could pack with old cooling was 85kWh. By some time around 2015, they pushed it to 90kWh due to the Model X and new cooling, and very soon after it was 100kWh for both, with either new cells or late improvements.
The largest attributale difference in energy density is between 90 and 100kWh, a difference of 10-12%, over the five years that Tesla has made those vehicles, or between ~55kWh and 75-80kWh for the original Roadster, a difference of 40% for around 8 years, but this may have also been helped by redesigned cooling *and* cell casings for the 18650s in the Model S and onwards.
It's less than a 5% change per year in cell energy for sure.
To address that last point, we feel your pain too. The industry is very opaque on the subject and they don't like selling these cells commercially.
I also have rented several times and traveled for work. I haven’t had an issue and it literally takes less than 2 hours each time vs paying for license tabs, insurance, maintenance, space in the garage, etc.
But to each their own.
A lot of misconceptions about Tesla's batteries and what cells do.
And "density" is no a word to use this loosely. The overal pack size stayedd the same yes, but the cells nor the chemisty changed at all ncessarily. Volume utilization improvements can only be done once. They can't be implemented again when swtiching to a new cell form factor. The S/Xpack might see slight cpacity improvements by going to larger modules, less module material taking up space wherecells could have been.
Tesla had deeply disappointed us in terms of density improvements. 5 years on since Model S, and the only improvement was the 85 -> 90 change which came with charge throttling because it's not as stable a chemistry as the 85 was.
JB and Elon mentioned a 15% chemistry only improvement they wereseeing. But it either didn't make it to Model 3, or it may become a very costly over the air upgrade some time in the future... ;-)
They increased capacity a bit (some disagree), and changed the label. The jury is still out on whether it really was 90kWh
"90" was around 86 kWh according to many. "100" is 102.4 kWh. Around a 19% increase. And all done to cramming more of the same cells in the same overall pack size and modules. Less space taken up by cooling. More space for cells.
And "density" is no a word to use this loosely. The overal pack size stayedd the same yes, but the cells nor the chemisty changed at all ncessarily. Volume utilization improvements can only be done once. They can't be implemented again when swtiching to a new cell form factor. The S/Xpack might see slight cpacity improvements by going to larger modules, less module material taking up space wherecells could have been.
Tesla had deeply disappointed us in terms of density improvements. 5 years on since Model S, and the only improvement was the 85 -> 90 change which came with charge throttling because it's not as stable a chemistry as the 85 was.
JB and Elon mentioned a 15% chemistry only improvement they wereseeing. But it either didn't make it to Model 3, or it may become a very costly over the air upgrade some time in the future... ;-)
Jason Hughes claims the 100kwh pack has reverted back to the "pre 90 kwh cell configuration "
but back to squeezing 200 kwh into the roadster:
If you run some numbers on what the bare cells are in weight, then look at the whole pack weight you come up with big weight numbers for the rest of the pack.
at 260 wh/kg just for the cells 85 kwh should only be 722 lbs for the 85 kwh cells. that's versus 1200 lbs for the whole pack per wikipedia. That's a whopping 1.66 factor on the cells by themselves. Now if you go to EV Wests site they say the weight of 1 module is 55 lbs.
Tesla Model S Lithium Ion Battery 18650 EV Module - 22.8 Volt, 5.3 kWh, EV West - Electric Vehicle Parts, Components, EVSE Charging Stations, Electric Car Conversion Kits
Multiply by 16 and you get 880 lbs. Still way short of 1200 lbs for the whole pack.....a 1.4 multiplier.
That's a lot of added weight on a percentage basis.
There's the big case that adds weight plus some heavy wiring plus the TMS snakes and liquid coolant.
So I think there's 2 places Tesla can save weight in the Roadster and truck packs.
1) double or triple the voltage to get the wire size down (we already know this).
2)Redesign the TMS.
BMW runs refrigerant directly in the pack versus glycol so that could save some weight along with a bottom cooling plate would allow closer spacing. Here's an article that describes a possible TMS change with bottom plate and refrigerant run directly in the pack
New Tesla P100D Battery Pack Conceptualized
In the truck some of the frame members may help shield the battery cells plus it is higher off the ground so perhaps less armor is needed around the cells in the truck.
My point is I think we will see a totally new pack design in the Roadster and truck with a new TMS system as well as much higher voltage to keep the current down.
All of these changes should be enough to use the current 2170 cell design in the Roadster and the truck.
Can you point me to where he said that? All I have seen him say is that he thinks the 100kWh pack uses a different chemistry than the 90kWh pack. I have never seen him say that it uses the same chemistry as the pre 90kWh packs.
Ahrgg that's a tough one since it requires wading through some very long TMC threads. I PM'd him. Hopefully he will get back.
I don’t know how many people you refer to when you say “us”, but I recommend you speak for yourself and not for others.
They selected 18650, because it was widely used and available in large quantities. They designed 2170, so I guess it is best size. Manufacturing cost are lower for 2170 back, because it needs less cells. I figured out one volume advantage for larger cell: Center of cell might not be as tightly packed as rest of it. See:
Capacity / volume is roughly same for 18650 & 2170. Change in chemistry will increase capacity, but they don't change it every year.
Brando
Active Member
The new 2170 cell, which is now being produced at the Gigafactory, is slightly larger – 21 mm by 70 mm. More importantly, it can store a lot more energy. According to Elon Musk, it's “the highest energy density cell in the world, and also the cheapest.” The 2170 cell is around 50% larger by volumethan the 18650, but it can deliver almost double the current (the 18650 delivers 3,000 mA, and the 2170 has been tested at 5,750-6,000 mA).
Tesla 2170 Battery Cells: Greater Power At Comparable Cost
google will find many other similar articles quoting Elon or JB.
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