Baseline for HV Battery SoH Performance

[ciaranob]

The TSB does not say much though -- it may be a slightly different cell without much impact in practice. That is my guess or otherwise Porsche may have made this more public ??

Also, I am not sure if we have enough data to draw any conclusion -- I think in my case the low score is due to a single cell; there is a screen in the Car Scanner that shows all cells as a bar graph and one of them was a bit lower than the rest. My car is in service now (for the Update) but when it gets back I'll post a screen shot.

EDITED TOTAL CAR COUNT AS I WAS MISTAKENLY COUNTING Summer/Winter data as separate cars i.e. there are only 8 Turbo/S cars in the spreadsheet (could be more but info not provided).

This is true i.e. the data we have here to date (of those that provided model info) shows that an additional 3 Turbo/S cars have an SoH range from 90.3 to 96.7 (vs the lower readings of the highlighted 5 cars) - only one of these is a 2022 model with two readings winter/summer at 92.7 and 96.7 SoH. So 5 of 8 Turbo/S cars appear to have low SoH, a high percentage of a small sample , but as you say these SoH readings may simply reflect a single bad cell (as discussed elsewhere). Nonetheless it may still be that the earlier cars for whatever reason may have had batteries with some quality control issues - TBD!

Sponsored

 

[ciaranob]

EDITED TOTAL CAR COUNT AS I WAS MISTAKENLY COUNTING Summer/Winter data as separate cars i.e. there are only 8 Turbo/S cars in the spreadsheet (could be more but info not provided).

This is true i.e. the data we have here to date (of those that provided model info) shows that an additional 3 Turbo/S cars have an SoH range from 90.3 to 96.7 (vs the lower readings of the highlighted 5 cars) - two of these are 2022 models (rest 2020/2021) at 92.7 and 96.7 SoH. So 5 of 8 Turbo/S cars appear to have 'anomalously' low SoH, a high percentage of a small sample , but as you say these SoH readings may simply reflect a single bad cell (as discussed elsewhere). Nonetheless it may still be that the earlier cars for whatever reason may have had batteries with some quality control issues - TBD!

Apologies - shouldn't be doing this whilst distracted as making silly errors!! - graphic a better description!

 

[whitex]

Apologies - shouldn't be doing this whilst distracted as making silly errors!! - graphic a better description!

Perhaps it would help visualize if you used different colored dots for turbo/s, GTS, perf battery, and regular battery. Then maybe grey dots for unknown cars.

 

[Bil49]

Hello to all,
first participation in this forum with the release of my taycan:
1) 11/2022
2) 96.27
3) 1629km
4) 207 KWh
5) 10/2022
1x 100%
2x <20%

 

[ciaranob]

Hello to all,
first participation in this forum with the release of my taycan:
1) 11/2022
2) 96.27
3) 1629km
4) 207 KWh
5) 10/2022
1x 100%
2x <20%

Will add later when I get free moment / thx for sharing and welcome!

 

[Scandinavian]

It’s suggested in this TSB: https://static.nhtsa.gov/odi/tsbs/2022/MC-10219388-0001.pdf

That is the One!

Modified Cell Chemistry! No information on why they hve done so but some change.

 

[ben1]

RWD Taycan. Location: Belgium
1) unknown
2) 95,38%
3) 8200km
4) 0 kwh (did not do any DC fast charging yet)
5) january 2022

Thanks for collecting this data. Very interesting.

 

[ciaranob]

RWD Taycan. Location: Belgium
1) unknown
2) 95,38%
3) 8200km
4) 0 kwh (did not do any DC fast charging yet)
5) january 2022

Thanks for collecting this data. Very interesting.

Thx for sharing - data added to charts in Post #1:
#1

 

[800v]

Just adding more info to my low SoH of 88.14% (2020 Turbo, 5810mi). Here is the cell voltage overview screen:

Where there is one cell that is clearly less than the rest, at 3.66v while the max is 3.674v. That is not much difference, but I think the worst cell determines the SoH (I think?) and thus that may explain the relatively low score.

But, for balance, the car is fantastic and I have no problem with range or anything so not sure how much to read into these numbers

Another weird thing is that the temperature display seems to show that some (every third!) cells are cooled less well? Do others have this too? Maybe this is completely normal though and those cells sit in the middle or further away from the cooling or something.

 

[ciaranob]

Just adding more info to my low SoH of 88.14% (2020 Turbo, 5810mi). Here is the cell voltage overview screen:

Where there is one cell that is clearly less than the rest, at 3.66v while the max is 3.675v. That is not much difference, but I think the worst cell determines the SoH (I think?) and thus that may explain the relatively low score.

But, for balance, the car is fantastic and I have no problem with range or anything so not sure how much to read into these numbers

Another weird thing is that the temperature display seems to show that some (every third!) cells are cooled less well? Do others have this too? Maybe this is completely normal though and those cells sit in the middle or further away from the cooling or something.

This is really interesting and thx for sharing - have not dived in enough to the various outputs TBH to replicate these data in my car - - are you using the Car Scanner app and assume fairly straightforward to locate and review these cell maps? In regards any bad cells recalibrating output I think that is correct but def no expert here and do not have enough knowledge of the cell packing etc to confirm or not your ideas re temp alternations etc. but the regularity would certainly seem to support something like this.

@rs38 would be good to have your insight here?

Cheers, C.

 

[800v]

This is really interesting and thx for sharing - have not dived in enough to the various outputs TBH to replicate these data in my car - - are you using the Car Scanner app and assume fairly straightforward to locate and review these cell maps?

Thanks! You can see these maps with the standard Car Scanner, just go to the dashboard and start swiping left until these ones show up

There is also one that shows the values of the min/max voltage of the cells:

 

[800v]

I am not aware of different chemistry in Taycans!

It’s suggested in this TSB: https://static.nhtsa.gov/odi/tsbs/2022/MC-10219388-0001.pdf

I don't want to derail this thread so we can move this if needed -- but anyway, here is a possible explanation for the changed chemistry.

I think the Taycan uses the LG chem E66A cell packs, which use NCM 712 chemistry.
Now, there were troubles with these packs in the Hyundai Kona where some vehicles caught fire (actually, just 2 cars in total I think) and it was traced back to manufacturing issues in some LG factories (in Holland, Michigan, and Ochang, Korea (source)). The issue seems to have been an interaction between a torn anode tab and folded separator which together could cause a short-circuit between anode and cathode.

Just to be clear this issue has not showed up in any Porsche as far as I know -- maybe because the Taycan cells were all produced by the LG Poland factory? Or maybe because the cell pouches are better situated in the Porsche so the chance of torn separators is much lower.

The Hyundai issue was apparently resolved by both changing the BMS software to detect the issue better, but also by applying an extra insulation coating on the cathode during production.

Now, I think that there is a possibility that the new chemistry mentioned in the Porsche TSB is actually still the same E66A cells but just with the insulation coating added.
(Complete guess though -- and it might be wrong since the TSB implies the BMS software needs a different configuration so that suggests a more significant change perhaps? but then, why would Porsche not be more public about it?)

 

[rs38]

this could be anything...
Porsche uses cells that are supposed/reported to have a certain Si part in the anode. This is a quite new technologie and known for more change in size when fully charged.
Someone with the right connections only could answer these questions. We even do not know what the heck is happening with the hv heaters that are dying so frequently...

 

[lcarron]

What is the difference between those two SOH indicator? I believe the one I need is the 91.76% but what is the other one?

 

[ciaranob]

What is the difference between those two SOH indicator? I believe the one I need is the 91.76% but what is the other one?

Suspect the BMS reading is for your 12v (LiPhos) battery. Less certain as to why there are 3 separate HV SoH’s!