Wiki Sudden Loss Of Range With 2019.16.x Software

[Droschke]

Question for the experts:

Is Li-Palting the only prerequisite for cell degradation?

In other words, knowing all cells will show certain degree of degradation as they age, should we assume all degraded cells have already been somewhat Li-Plated?

If Li-Plating can lead to the development of dendrites and trigger possible separator puncture, hence shorting the cell and start a fire, AND assuming the reported fire incidents with 85 kWh batteries are the examples, shouldn't Tesla's BMS have already detected these hazardous conditions much earlier on and have taken preventative measures before these fires? If yes, doesn't that point to a faulty BMS that has been putting these batteries at risk?

 

[egn1]

There are two main degradation modes:
- lithium plating caused by cycling
- electrolyte degradation caused by calendar aging

Both have different parameters that cause degradation. I.e. low temperature is bad for cycling, but good for calendar aging.

 

[u1e85d5]

Normal battery degradation is caused by growth of the solid electrolyte interface, i.e. electrolyte that reacted with the lithiated graphite electrode.

See this video at 15:10

Lithium plating can also cause degradation but is not normal afaik. If you are successful in never ever getting your cell voltage above 4.2V, there should be no plating at all. This is very hard to do in reality though due to the reasons in my earlier posts. (many factors, cells in series)

 

[egn1]

Lithium plating can also cause degradation but is not normal afaik. If you are successful in never ever getting your cell voltage above 4.2V, there should be no plating at all. This is very hard to do in reality though due to the reasons in my earlier posts. (many factors, cells in series)

It is very easy for the BMS to keep the voltage below a specific value in batteries with multiple cells in series. Actually, it is the main purpose of the BMS to keep voltage of all series cells within a specific voltage range.

Lithium plating happens also on much lower voltage than 4.2 V depending on temeperature and charge current.

Please read the paper of Dr. Peter Keil.

 

[Droschke]

Thanks so much @egn1 and @u1e85d5:

I should have numbered my two questions. Will you be able to answer each question separately?

I'm rewording them for more clarity, below:

1) Is Li-Palting the only prerequisite for cell degradation? In other words, knowing all cells will show certain degree of degradation as they age, should we assume all degraded cells have already been somewhat Li-Plated?

2) If Li-Plating can lead to the development of dendrites and trigger possible separator puncture, hence shorting the cell and start a fire, AND assuming the reported fire incidents with 85 kWh batteries are the examples, shouldn't Tesla's BMS have already detected these hazardous conditions much earlier on and have taken preventative measures before these fires? If yes, doesn't that point to a faulty BMS that has been putting these batteries at risk?

 

[Ferrycraigs]

There has been lots of talk about Dendrites, and how they are bad for batteries, and could potentially cause battery fires. Worrying. There has been speculation that Tesla went looking for Dendrites, didn’t find any, but did find Li Plating.

This article shows the other side of the coin, and explains one method of controlling Dendrites. It did make we wonder if high powered Supercharging might be linked to there being a surprising absence of Dendrites. But I am conscious that this may be two and two equalling nine! But I found it an interesting read.

Fire-starting battery dendrites go with the flow

 

[FredTMC]

I have now looked at three S 60 and they all have about the same max rated range (160, 165, 165). They also show full charging capacity (4.20v). At least one has not upgraded to 16.1.1.
So, the 60s I have seen do not show condition Z but REAL degradation of 23%.

I’m shocked by this max Rated Range data points of 165 miles.

I’m still getting 188 miles at 100% charge.

I have a 2013 Model S 60 has ~115K miles. Original battery (208 when new).

 

[Droschke]

There has been lots of talk about Dendrites, and how they are bad for batteries, and could potentially cause battery fires. Worrying. There has been speculation that Tesla went looking for Dendrites, didn’t find any, but did find Li Plating.

This article shows the other side of the coin, and explains one method of controlling Dendrites. It did make we wonder if high powered Supercharging might be linked to there being a surprising absence of Dendrites. But I am conscious that this may be two and two equalling nine! But I found it an interesting read.

Fire-starting battery dendrites go with the flow

@Ferrycraigs, Thanks for linking this article. Very interesting. Besides the fact that long ago I read somewhere (I think it was associated with the crowdsourced data on the Tesla degaration stats), that the cars with higher supercharging usage were showing much less degradation.

Wouldn't be nice to have the BMS detect the need and have the superchargers automatically generate short bursts of current to flatten spiny growths on our lithium metal anodes?

 

[Ferrycraigs]

@Ferrycraigs,Wouldn't be nice to have the BMS detect the need and have the superchargers automatically generate short bursts of current to flatten spiny growths on our lithium metal anodes?

Exactly my thought, quickly followed by the possible irony that lots of Supercharging may have been, unintentionally, beneficial, but now they are actively taking steps to overcome that.

 

[u1e85d5]

It is very easy for the BMS to keep the voltage below a specific value in batteries with multiple cells in series. Actually, it is the main purpose of the BMS to keep voltage of all series cells within a specific voltage range.

Lithium plating happens also on much lower voltage than 4.2 V depending on temeperature and charge current.

Please read the paper of Dr. Peter Keil.

Yes, you are right. It happens at cell voltages lower than 4.2V. I guess my point of view is hard to explain.
The surface of the cell is big and there are spots of different resistance, thickness, temperature gradients and so on. These effects can and do lead to the situation that your relative voltage goes below 0V creating metallic lithium. A BMS is somewhat good in keeping the cells at whatever voltage +/- a few %. But that's always an average over the whole active surface and it cannot know the exact maximum and minmum.

Either way here is yet another article going very deep on Li plating:
https://www.researchgate.net/public...thium_plating_issues_in_lithium-ion_batteries

 

[lightningltd]

There has been lots of talk about Dendrites, and how they are bad for batteries, and could potentially cause battery fires. Worrying. There has been speculation that Tesla went looking for Dendrites, didn’t find any, but did find Li Plating.

This article shows the other side of the coin, and explains one method of controlling Dendrites. It did make we wonder if high powered Supercharging might be linked to there being a surprising absence of Dendrites. But I am conscious that this may be two and two equalling nine! But I found it an interesting read.

Fire-starting battery dendrites go with the flow

Interesting read. Unfortunately, the trolls took over the comments on that site

As to the theory that it could be caused by charging / supercharging a cold battery, I primarily supercharge and also charge at work on 120 volts (to keep the battery maintained).
I have never charged the battery cold. The minimum drive to get to the charger is a 15 minute freeway drive at 65mph, plenty of time for the battery to warm up...
Pre update I had 256 RATED miles at 100%. Now I have 216 RATED miles at 100%. ALso, the Maximum charge rate I am seeing is 60kw. Takes MUCH longer to charge. It makes long road trips nearly impossible due to the extra time not to mention that even at the new 100% there are places I can no longer get to that I have been to many times.

Minor inconvenience? Slight reduction in range? a small bit longer to charge? I thing NOT!
It is hard to speculate with any accuracy when Tesla is being so secretive and minimizing the issue like its only affecting 10-12 cars.

And for them to tell drivers that its their driving habits is sheer lunacy. FESS UP TESLA.

 

[Droschke]

Pre update I had 256 RATED miles at 100%. Now I have 216 RATED miles at 100%.

40 miles loss? That's not slight reduction!

 

[Leeboy22001]

I’m shocked by this max Rated Range data points of 165 miles.

I’m still getting 188 miles at 100% charge.

I have a 2013 Model S 60 has ~115K miles. Original battery (208 when new).

Yep, I'm on 164 miles typical, 208 new. Max cell voltage at 100% is 4.056V, lost 10% on 2019.16.2 update.

 

[Guy V]

40 miles loss? That's not slight reduction!

It is very sad to hear, and more so to experience, but then it's still not 30% which would be 185 miles from 265.

I certainly do hope Tesla has some plan for remediation rather than stand by 30% being reasonable. Personally I would be satisfied by a refurbishment fee with extended warranty for something under 10% of the original cost of the car. It wouldn't make much sense for a new replacement battery for $20K for used cars with market values in the 30's (with apparently good batteries).

If Tesla doesn't do something very constructive here two very negative things will happen. First, the resale values of any of their cars that may seem to be in the affected groups will plunge to almost nothing. Secondly, they could generally be seen to become cars that could lose 30% of their advertised range in just a few years and have ultimate practical useful lives of only the 8-year warranty. What fraction of purchasers will be willing to accept that?

I very much expect something to be done about this. I am waiting for which comes first, the Tesla response or the market hysteria...

 

[lightningltd]

40 miles loss? That's not slight reduction!

Not to mention the cost in extra time supercharging. I thought they wanted to REDUCE time on the supercharger?

The calculated KW from new to pre-update to now (135,000 miles)
Using RATED miles x .295 (EPA) (calculated, for comparison only, nothing to debate for the math purists )
New: 265 Miles X .295 = 78.175 KW
Pre Update: 256 Miles X .295 = 75.52 KW (3.4% degradation from new)
Post Update: 216 Miles X .295 = 63.72 KW (18.49% drop from new)

Charge habit (2 coast to coast trips not withstanding):
Supercharge 5 days a week on the way to work (after a 15 minute freeway drive at 65 MPH) to 70-75%
Plug into 120 Volt AC while at work (8.5 hours per day, 5 days a week).

Of course, now my habits have had to adjust for the 50%+ slower charging (leaving earlier for work)

And Tesla calls the sudden loss 'normal degradation', but said they did not know why it happened all at once
No faults found in logs according to them.

 

[lightningltd]

It is very sad to hear, and more so to experience, but then it's still not 30% which would be 185 miles from 265.

I certainly do hope Tesla has some plan for remediation rather than stand by 30% being reasonable. Personally I would be satisfied by a refurbishment fee with extended warranty for something under 10% of the original cost of the car. It wouldn't make much sense for a new replacement battery for $20K for used cars with market values in the 30's (with apparently good batteries).

If Tesla doesn't do something very constructive here two very negative things will happen. First, the resale values of any of their cars that may seem to be in the affected groups will plunge to almost nothing. Secondly, they could generally be seen to become cars that could lose 30% of their advertised range in just a few years and have ultimate practical useful lives of only the 8-year warranty. What fraction of purchasers will be willing to accept that?

I very much expect something to be done about this. I am waiting for which comes first, the Tesla response or the market hysteria...

The 30% is for the model 3. So far, all I have heard is 20% below the fleet average for the type and age of the battery, which varies each time a different tech tells you. Basically, there is not an apparent policy so they tell you what they want. I do know they claim to consult an engineer before they say the engineer says all is normal and within the range parameters (but will not share the data for competitive reasons).
They must have a hotline to the engineers, because the last time they said that the response was received via text 2 minutes later (rofl).

 

[Guy V]

The 30% is for the model 3. So far, all I have heard is 20% below the fleet average for the type and age of the battery, which varies each time a different tech tells you. Basically, there is not an apparent policy so they tell you what they want. I do know they claim to consult an engineer before they say the engineer says all is normal and within the range parameters (but will not share the data for competitive reasons).

I said 30% because that is for the Model 3, that is most of what they are now selling and it is the only concrete guideline to battery life that they publicly provide to this point. No purchaser is going to have any expectation of anything more than that going forward unless they deal with this.

 

[Ferrycraigs]

It is very sad to hear, and more so to experience, but then it's still not 30% which would be 185 miles from 265.

I certainly do hope Tesla has some plan for remediation rather than stand by 30% being reasonable. Personally I would be satisfied by a refurbishment fee with extended warranty for something under 10% of the original cost of the car. It wouldn't make much sense for a new replacement battery for $20K for used cars with market values in the 30's (with apparently good batteries).

If Tesla doesn't do something very constructive here two very negative things will happen. First, the resale values of any of their cars that may seem to be in the affected groups will plunge to almost nothing. Secondly, they could generally be seen to become cars that could lose 30% of their advertised range in just a few years and have ultimate practical useful lives of only the 8-year warranty. What fraction of purchasers will be willing to accept that?

I very much expect something to be done about this. I am waiting for which comes first, the Tesla response or the market hysteria...

I was thinking today what is it I actually want to happen. Do I want a battery replacement? With a new battery, or even a refurbished battery? Nope. I want my old battery, that I have cosseted for 3 years, de-restricted. That’s all. Return Vmax to 4.2V. I get my range back. I get my consumption figures back, and I lose the extraordinary levels of Vampire drain (sometimes 4% per night). And it should be easy. If some reports are correct, Tesla seem to be aware the restriction is unnecessary, and non effective, but prefer to leave it in place whilst they sort the dodgy coding. I would rather they reverse the restrictions whilst they sort the dodgy coding.

 

[DILIE]

Use TM Spy or scan my tesla to look at battery capacity- probably a good exercise even apart from this latest situation.

I would say just put the display in percentage mode and then switch to miles. Divide current miles by percentage to find 100% range. If the 100% range is less than <some number you decide is the lowest you'll accept> don't buy it. Doesn't matter why the range is low.

Many 2014-2015 MS85 have significantly less than 10% (real) degradation. That's probably the benchmark I'd use.

 

[DJRas]

The 30% is for the model 3. So far, all I have heard is 20% below the fleet average for the type and age of the battery, which varies each time a different tech tells you. Basically, there is not an apparent policy so they tell you what they want. I do know they claim to consult an engineer before they say the engineer says all is normal and within the range parameters (but will not share the data for competitive reasons).
They must have a hotline to the engineers, because the last time they said that the response was received via text 2 minutes later (rofl).

No, the tech said the standard is 10% below fleet-wide average at the current mileage.
But, they would not print this out or let me take a screen shot