Tesla battery longevity not affected by frequent Supercharging, study says

[eevee-fan]

I saw this. How does he know that his battery death was from Supercharging? Any number of things could have gone wrong that caused it. Also, he paid $9k for a refurbished battery with 14%? That was a bad purchase...would rather explore getting a new battery for $15k with a full battery warranty.

He is also the only one that i've seen have this issue. Are there any other ride share people out there that have battery death with Supercharging. Seems anecdotal.

Seems it is up to Tesla Service Center what he is ALLOWED to buy. Seems Tesla will not sell you a new pack!

Might be an anomaly. I would have expected NMC pack to be good for at least 200-300k miles. I have LFP and I expect at least 500k, probably more like 1M miles over its life (I would never be driving that much, maybe next few owners).

 

[AAKEE]

Might be an anomaly. I would have expected NMC pack to be good for at least 200-300k miles.

Didnt watch the vid for more than a few seconds, but Model 3 in USA and all early model 3 had Panasonic NCA.

The lithium batteries degrade from calendar aging AND cyclic aging. It is not only a ”miles” thing.
Supercharging causes lithium plating which in turn (long term) leads to short circuits in the cells. Extensive supercharging will finally end up in the battery dying when one or a few cells short.

 

[nicksp]

What? They only tested 12.5k? Talk to us when you test a million.

 

[android04]

Seems it is up to Tesla Service Center what he is ALLOWED to buy. Seems Tesla will not sell you a new pack!

Might be an anomaly. I would have expected NMC pack to be good for at least 200-300k miles. I have LFP and I expect at least 500k, probably more like 1M miles over its life (I would never be driving that much, maybe next few owners).

Tesla will sell you a new pack, but it will cost more money.

 

[Physicslawyer]

Here's my study of n=2. I had a new 2022 MYP that I supercharged exclusively. I charged it to 100% twice a week and to over 90% on the other days. I put 4k miles a month until it had around 17k miles.

I bought a 2022 MYP with 3k miles that I have religiously followed charging guidelines and have only supercharged for 11% of the 13k miles I have on it.

The first was at 287 miles at 17k miles. This second one has more battery degradation. I'm at 286 miles at 13k miles. I got the car Feb '23

Home- vacation home (where it lives mostly)
Other- main home
(for the screenshot)

NOTE: the only reason I have Supercharged at all is that my "305" mile car can't make it 200 miles without stopping to charge without risking getting home with around 11% charge. I'm not comfortable going that low. I get home closer to 20%.

 

[AAKEE]

Here's my study of n=2. I had a new 2022 MYP that I supercharged exclusively. I charged it to 100% twice a week and to over 90% on the other days. I put 4k miles a month until it had around 17k miles.

I bought a 2022 MYP with 3k miles that I have religiously followed charging guidelines and have only supercharged for 11% of the 13k miles I have on it.

The first was at 287 miles at 17k miles. This second one has more battery degradation. I'm at 286 miles at 13k miles. I got the car Feb '23

It’s a bit short time for evaluation.
In the beginning of the battery life the calendar aging will cause the absolute biggest part of the degradation.

For normal climates we can expect the calendar aging to be about 5% the first year (when charging to 70-100%).

As it seems, fast charging doesnt show very much reduction in range. But we know that it causes lithium plating which is not good if we get too much of it.

The research shows that lithium plating can revert from normal cycles, and specially cycles at low SOC.
So supercharging only when needed or from time to time most probably gives the battery time between to revert a part of the lithium plating and (recover the capacity slightly).
If supercharged / fast charged too often during a long time, we will get short circiuts in the cells.

I know about one Model 3 Performance (2019) that was mostly supercharged and the battery only showed 12% degradation (checked with Scan my tesla, so ~10% loss of range) where the battery failed after about 200K km. Out of the warranty the car was fixed at a third part shop which changed the battery and also checked the reason for the dead battery. It was a few completely dead cells.
My take from that is that it was a lithium plating issue from supercharging.

We should not be afraid to supercharge, but doing it all the time for very many miles might cause issues.
Supercharging when needed but not always most probably give the battery the time/cy les it need to release some parts of the lithium plating.

 

[Regaj]

There are a number of incorrect statements in the Recurrent article (starting with "Preconditioning is when the car’s thermal management system pre-cools the battery so it can accept a higher charge rate without overheating"... and the article continues with several more misstatements after that). Enough to give one pause regarding the rest of their "data." It totally lacks the rigor one would expect to see in any kind of scientific analysis. Notwithstanding that we would all cheer its conclusion that Supercharging poses no threat to our batteries, were that true - something patently false - let's just call it what it is. A puff piece.

Tesla's thermal management system is not nearly as efficient as many think. It is very slow to heat the back when preconditioning. And it is very slow to cool the pack when temps are elevated, such as after a Supercharging session.

Lithium plating is probably the worst thing we can do to our battery packs. That's a largely irreversible process. Yes, some plating can be recovered, but the percentage is quite modest. Lithium plating is mostly a one-way street.

We think of Lithium plating as mostly a cold weather phenomenon, because its effects are most dramatically observed at lowered temps. But it can happen even at quite modest temperatures - and, if the C-rate is high enough, even at temperatures that we think of as elevated . People think of preconditioning while navigating to a Supercharger as necessary to get as high a charge rate as possible - and certainly it does that. But the larger, more important reason (and the reason the charge rate is reduced if your pack temp isn't high enough) is to get the battery hot enough to avoid Lithium plating.

All that said, Tesla's BMS does a pretty decent job at minimizing - but not eliminating - Lithium plating. What Tesla's BMS is less great at is controlling pack heat once it becomes elevated. And what nearly all scientific studies show is that heat is a fantastic accelerant of Lithium battery degradation.

The gentleman profiled in the Kim Java video is about the worst case scenario for Supercharging. That said, his use case is very akin to the scenario Elon keeps promoting with the Robo Taxi concept. One could make an argument that battery technology is the limiting factor in that Robo Taxi concept every bit as much as fully autonomous Full Self Driving.

 

[eevee-fan]

So does DCFC at lower power sites be beneficial to battery life? Example, 72 kW SuC, Chargepoint 62 kW DCFC, EVgo 50 kW DCFC.

 

[AAKEE]

So does DCFC at lower power sites be beneficial to battery life? Example, 72 kW SuC, Chargepoint 62 kW DCFC, EVgo 50 kW DCFC.

Yes, most probably.

Reducing the charge power down to about 0.3C (thats 0.3x the capacity in power, so 25kW for a model 3/Y LR/P)

This test is on a panasonic NCR18650 similar to The chemistry Tesla use.

The cell is 2.9Ah so 3A would be about the same as 75kWh charging on a model 3/Y.

1A is similar to about 25kW
2A about 50kW

Tesla heats the cells during DC charging so most probable the (worse) effect of higher charge power is reduced and the diffwrence between these would be smaller.

 

[nicksp]

Tesla battery longevity not affected by frequent Supercharging, study says

Tesla battery degradation is not accelerated by frequent Supercharging, which was previously thought, according to an extensive new study. It...

electrek.co

Tesla battery degradation is not accelerated by frequent Supercharging, which was previously thought, according to an extensive new study.

It has long been believed in the industry that frequent DC fast charging is bad for battery longevity; even Tesla used to warn against it.
But we have never seen strong data that support that assertion when it comes to Tesla vehicles, where we have more data on than any other electric vehicles.

In its most recent update about battery degradation, Tesla says that its vehicles lose only about 12% after 200,000 miles.

A new report from Recurrent, which has access to data from over 12,500 Tesla vehicles in the US through its software service, now shows clearly that there’s little to no difference in battery degradation between frequent fast charging and rare fast charging:





As you can see from the charts, the data shows the same result for Model 3, and frequent fast charging actually makes long-term battery degradation a bit better on Model Y.

Interestingly, Recurrent focused on the extreme cases. Here’s how they qualified the vehicles that frequently fast charge versus those that rarely fast charge:


In Tesla’s owner manual, the automaker doesn’t talk about frequent DC fast charging affecting battery longevity anymore, but it does mention the potential to “decrease slightly” the peak charging rate:


However, they also warned about fast charging under extreme heat or extreme cold, which is not ideal for battery performance. To be fair, extreme heat and cold are also not good for internal combustion engine vehicles.

I think I'm going to believe individual opinions, endless debating and extensive charts that tell me to charge up to 60% on even days and 70% on odd days of the month. Extensive studies be damned.

 

[eevee-fan]

Yes, most probably.

Reducing the charge power down to about 0.3C (thats 0.3x the capacity in power, so 25kW for a model 3/Y LR/P)

This test is on a panasonic NCR18650 similar to The chemistry Tesla use.

The cell is 2.9Ah so 3A would be about the same as 75kWh charging on a model 3/Y.

1A is similar to about 25kW
2A about 50kW

View attachment 988141

Tesla heats the cells during DC charging so most probable the (worse) effect of higher charge power is reduced and the diffwrence between these would be smaller.

This is great news because I have the LFP model (so 58 kWh) and I think the highest charge rate I got from a CP 62kW DCFC was 57 kW. The 50 kW EVgo = 45 kW. So both are <1C.

 

[RSpanner]

My 2020 M3LR shows 300 but i can never get even 200 miles distance traveled.

How do you drive it? Do you hit 80 on the freeway? do you accelerate like crazy? what?

 

[shahryaran]

How do you drive it? Do you hit 80 on the freeway? do you accelerate like crazy? what?

City only
Sometimes hit the pedal

 

[Piwacet]

So if I'm going to do this lithium plating recovery thing, what state of charge do I want? And then let the car sit at that state of charge for 2 days?

Thanks.

 

[RSpanner]

City only
Sometimes hit the pedal

That is totally understandable..probably is what or how most people drive. Do you know your average watts per mile? I have not memorized mine but will check. I think it is very difficult to have things work out were getting 300 miles per charge would be an average..quasi impossibile, si?

 

[Gentlynapping]

Admittedly I’m not knowledgeable about fast charging and degradation but these results don’t make sense to me. How do they explain that model Y cars who did lots of fast charging suddenly do better than slower charging after 800 days. Does that make scientific sense given the type of battery involved? Likewise with the 3. Slow charging does better better better until 800 charges then does worse. Then about 1700 does better until 1800 then craters until 2000 where it jumps back up to meet the rapid charging group.

Please educate me. Just trying to learn. It’s mostly the fluctuations between better and worse that I don’t understand. If there is no difference, shouldn’t there consistently be no difference? Thanks

I think most of the crossing over of the curves is just statistical noise, particularly for the Model 3 data. If there were error bars drawn over the curves you would likely see that the small deviations between the curves are not statistically significant. The Model 3 lines cross over each other several times which is consistent with random statistical variation.

The Model Y data probably also isn’t statistically significant but is a little more interesting because there is an autocorrelation between 200 and 800 days. That is all the data points for the blue line (frequent fast charge) are below the green line during that time period. After 800 days, the lines cross over but there are probably a lot fewer cars at 800 days so the final crossover may just be statistical noise. Therefore, I don’t think you can rule out a small lowering of battery life with frequent fast charging in the Model Y using this data. Judging by the separation in the curves between 200 and 800 days, the degradation effect would be very small, less than 1% of total range and therefore not very important in real life usage.

 

[DrChaos]

All that said, Tesla's BMS does a pretty decent job at minimizing - but not eliminating - Lithium plating. What Tesla's BMS is less great at is controlling pack heat once it becomes elevated. And what nearly all scientific studies show is that heat is a fantastic accelerant of Lithium battery degradation.

That's true, but for calendar aging, total time at high temperature matters and unless you have 24/7 robotaxi usage, the time interval at high temps from supercharging is likely to be low, compared to environment in a Phoenix summer for instance.

if you have 24/7 robotaxi usage then the revenue might overcome it. And eventually true 24/7 robotaxis will probably be running LFP packs (as LFP buses in China do) and when capacity gets low, the dispatcher will just send them to shorter distance fares and recharge them more often.