Is Tesla making progress in improving battery energy density?

[strider]

Ditto!!!!!

People who deal with a less quality ride for that once in a year “what if” scenario, seems silly. Rent for that one time a year. It’s like people who complain about long fill ups for Tesla for that once in a year road trip but then are fine with being inconvenienced 51 other weeks a year with not being able to fill up at home.

I assume you were speaking in general (and I completely agree with you), but if it was in response to @daniel, he already has a freaking Roadster as his daily driver! He keeps the Prius for a few trips/year. The cost to keep that car is low. It's paid for, insurance is likely low as it's an older, small car, I don't know what tags cost in WA but on an older car likely not much. At the end of the day, dealing with rental places suck. I used to travel a ton for work and still travel some now. It's more common for a rental place to NOT have the car I reserved than for them TO have it. You simply cannot rely on them. It's the same reason we keep a Diesel Grand Cherokee. Yes, I could rent a truck or SUV for that few times/year but my time and lower stress level is worth way more.

 

[Brando]

If you take a look at the following thread, we're pretty confident that the Semi is <850kWh & <1.7 Wh/mile with Model 3 cell assumptions.
Lets work out the Tesla Semi-Truck Technical Specs

If it indeed true that the Semi and the 2020 Roadster have an improved chemistry, why wasn't it obvious in the Model 3?

Isn't battery chemistry "tweaked" every year? Isn't this the reason for the oft stated continuous battery improvements of 5-7% each year on average? doubling per decade improvement since 1992?

 

[JKolodziejski]

Isn't battery chemistry "tweaked" every year? Isn't this the reason for the oft stated continuous battery improvements of 5-7% each year on average? doubling per decade improvement since 1992?

We haven't actually seen much evidence of that from the Model S since Elon said that statement.

The 100 kWh pack's cells are still only 250 Wh/kg.

 

[Brando]

We haven't actually seen much evidence of that from the Model S since Elon said that statement.

The 100 kWh pack's cells are still only 250 Wh/kg.

I find 60 kWh in 2011/12 and by 2016 100 kWh. Is this OK with you? or still not fast enough improvement?
I'd also point to Roadster 3.0 battery upgrade. How does that meet your expectations? - I know, not Model S.

Do you happen to have a timeline of Wh/kg of Lithium Ion batteries? I failed in my quick searches to find density chart over time. That would be interesting to see.

PS - Elon was NOT the only one to say Li Ion batteries performance improves about 6-7% per year or about double every 10 years. Sadly I didn't find a chart from 1990-2016 to show performance nor density. Anyone??

 

[jkn]

Changing battery chemistry involves risk that new battery does not last 8 years. Testing it is slow. They have a new fast testing system which speeds up battery development (perhaps 10*), but I wouldn't trust it to absolutely certainly predict 8 years life time.

My guess is they already have new higher energy density battery for R2 and semi. It will be first used on a new back for most expensive S&X. If it is only small step up (110 - 120 kWh), they promise even larger back soon. All this to make sure not too many will buy it. So that in worst case they'll have to replace thousands batteries instead of 100 thousands. If they sell it at twice of manufacturing costs, they have money to replace it.

 

[Prim3]

What cells are they using? They don't necessarily have to stack rows of 2170's or 1860's. Just run a large cell size, say a 26650. You would have less storage material and the same amount of actual lithium, discharge rate can stay the same.

 

[Prim3]

Do you happen to have a timeline of Wh/kg of Lithium Ion batteries? I failed in my quick searches to find density chart over time. That would be interesting to see.

PS - Elon was NOT the only one to say Li Ion batteries performance improves about 6-7% per year or about double every 10 years. Sadly I didn't find a chart from 1990-2016 to show performance nor density. Anyone??

He may be referring to overall, not just standard cell performance. It would be hard quantify the efficiency of lithium as a whole, due to many factors such as more efficient motors (Ie Brushless in power tools). People need to understand that cars are a small driver in the lithium market. The demand for Innovation comes from the masses, IE cell phones and other basic electronic devices.

I would say just guesstimating (I hate to do this) but he is definitely right on the money. At the shop we now are able to run full blown machines that require not only a high constant flow but also insane peak draw as well. This has never been the case, or if it has it's been for very brief periods of time. Again this is just my industry but I do see a very apparent correlation.

 

[jkn]

What cells are they using? They don't necessarily have to stack rows of 2170's or 1860's. Just run a large cell size, say a 26650. You would have less storage material and the same amount of actual lithium, discharge rate can stay the same.

For same mechanical strength larger cells need thicker walls. Total % material for case is same.
Larger cells produces larger current, so it needs thicker conductors.
Heat has to travel longer distance in larger cell. Because of this smaller cell has an advantage.

Smaller cells are better. It is not coincidence, that best battery back is made of small cells. M3 cells are slightly larger to reduce manufacturing costs. I believe they found it is small enough. If larger cells were better, M3 would have much larger cells.

 

[jkn]

He may be referring to overall, not just standard cell performance. It would be hard quantify the efficiency of lithium as a whole, due to many factors such as more efficient motors (Ie Brushless in power tools). People need to understand that cars are a small driver in the lithium market. The demand for Innovation comes from the masses, IE cell phones and other basic electronic devices.

I would say just guesstimating (I hate to do this) but he is definitely right on the money. At the shop we now are able to run full blown machines that require not only a high constant flow but also insane peak draw as well. This has never been the case, or if it has it's been for very brief periods of time. Again this is just my industry but I do see a very apparent correlation.

Never before has so much money used for battery development. It will give results. My guess is MS & MX will get 120 kWh battery soon. Perhaps before summer.

https://www.quora.com/Is-there-an-updated-Li-ion-battery-energy-density-projection-graph

(It was easy to find. Perhaps I have done technical & scientific searches instead of cat videos, so Google AI knows what I want.)

 

[daniel]

... Perhaps I have done technical & scientific searches instead of cat videos, so Google AI knows what I want.)

I don't think you're allowed to be on the internet if you don't spend at least half your on-line time watching cat videos.

 

[Brando]

@jkn - thanks, great link

Why do Li-ion Batteries die ? and how to improve the situation?

Professor Jeff Dahn (Dalhousie University)
Dal battery researcher Jeff Dahn honoured with inaugural Governor General's Innovation Award

hope this helps

 

[jkn]

@jkn - thanks, great link

Why do Li-ion Batteries die ? and how to improve the situation?

Professor Jeff Dahn (Dalhousie University)
Dal battery researcher Jeff Dahn honoured with inaugural Governor General's Innovation Award

hope this helps

I have linked that video earlier, but perhaps not on this forum. This is why I think energy density will increase:
Tesla battery researcher unveils new chemistry to increase lifecycle at high voltage
"Those are already pretty good results, but Tesla aims to do better with Jeff Dahn, a renowned battery researcher and the leader of Tesla’s research partnership through his battery-research group at Dalhousie University."

 

[daniel]

That video is an hour and a quarter long. I imagine there are people who have the time and interest to watch that. For the rest of us, anybody care to summarize?

 

[SmartElectric]

That video is an hour and a quarter long...anybody care to summarize?

Dahn is a Canadian rock and roll genius battery scientist and one of the top innovators in his field. He helped pioneer the current state of the art lithium ion battery and has found scientific methods to measure battery longevity and effectiveness using test methods which take days instead of years to show how well a chemistry or construction performs. This allows engineering agility and reduces time to market for next generation of cells.

Big fan!

 

[jkn]

That video is an hour and a quarter long. I imagine there are people who have the time and interest to watch that. For the rest of us, anybody care to summarize?

You need to watch it to really understand.
SmartElectric already answered. Mine is slightly different:
He uses voltage and current measurements during charge-discharge cycles to probe chemical changes inside a cell. Measuring very accurately few cycles can predict how many cycles cell has left, even if it has 10000. -> Developing long life cells becomes much faster.


A short cat & bird video for those who don't watch long lectures:

 

[daniel]

Thanks for the summaries. The in-depth tech stuff would probably go right over my head.

 

[jkn]

Thanks for the summaries. The in-depth tech stuff would probably go right over my head.

It is not impossible to understand. No chemistry or math studies are needed. He only measures voltages very accurately. But there are many steps to get to final goal, so it requires time and good memory to follow (watching it once might not be enough). If I try simple explanation, it will be misunderstood.

 

[daniel]

It is not impossible to understand. No chemistry or math studies are needed. He only measures voltages very accurately. But there are many steps to get to final goal, so it requires time and good memory to follow (watching it once might not be enough). If I try simple explanation, it will be misunderstood.

The fact that he is "measuring voltages very carefully to determine cycle life" is all the information I really need. The only other information I'd want won't be available from the video, which is: Does his method work? Is he legit or a nut case? But I'm happy to assume he's legit and the method works, and will help accelerate the pace of battery development.

 

[Cloxxki]

A 30% improvement in energy density over the model 3 solves all the roadster and semi battery issues. The 30% improvement of the batteries in the model 3 over the original model S is somewhat less than expected improvement over 5 years. Jumping another 30% in three years would still leave very reasonable total growth for the decade.

Let's first see any HINT that there is even a 1% density improvement in 2170's seen in Model 3 over the 18650's in S/X. Did you see any math done thatt indicated any true density gain? I've missed it then. I heard promise and whispers, even Elon and JD mentioning 15% just for chemistry seen in the lab.
47% larger nominally per cells, 4416 of them to make 80.5 kWh (75 kWh if you believe many others), nothing special in terms of density there.
The 2017 S/X don't even have much over the 2012 Model S. And the original was better suited for repeated fast charging. I am yet to see any real improvement over 2012 that's more than the expected annual improvement. After 5 years being THE hottest tech company.

 

[jkn]

The fact that he is "measuring voltages very carefully to determine cycle life" is all the information I really need. The only other information I'd want won't be available from the video, which is: Does his method work? Is he legit or a nut case? But I'm happy to assume he's legit and the method works, and will help accelerate the pace of battery development.

Of course I don't have personal experience, but video makes sense. It is easy to verify that method detects known bad cells. To prove that cell lasts long time with traditional method will of course take time. Only doubt I have is that this method might not detect all mechanisms causing aging. Even so with this method they can test 10 (100?) chemicals in same time they used to test one.

I understood Tesla has not charged cells to 100%, in order to extend life time. Now they can verify that there is no electrochemical aging with 100% charge. Capacity will increase.

The 2017 S/X don't even have much over the 2012 Model S. And the original was better suited for repeated fast charging. I am yet to see any real improvement over 2012 that's more than the expected annual improvement. After 5 years being THE hottest tech company.

I believe this is so because Tesla does not want to risk with new chemistry. If new chemistry fails in 4 years, they would be in trouble. No real competition, so why risk it?

( I have bad experience of writing after midnight. I don't feel too tired now...)