Well, it will not be easy to show exact numbers, but principles is easier.
The main degradation that comes from charging is lithium plating. With a cold battery the lithium ions can not move very quick so a high charging current causes the lithium ions to stuck up to blobs like a traffic jam. The warmer the battery the more freely the lithium ions can flow, not causing any blobs.
Most research test degradation from fast charging cycles with non heated cells, so 25C or so. They also mostly do fixed current charges until the charging voltage reach 4.2V, and tesla reduce the charging power a bit more than this at it seems.
There is research reports that shows that preheating the cells to 40C or more reduce the lithium plating to a minimum.
At 1C charing rate (80kW for a 80kWh battery etc.) we need to have a battery temperature above 20C, and as we charge with about 3-3.5C at the fastest rate in a SuC V3 we need to have a higher battery temp.
I always preheat completely, when possible. I know Tesla reduces the charging speed if the battery was not preheated, but still I think the best thing should be to make a conmplete preheating.
Tesla did change the cell temp target recently, before I think all SuC had 48C target but now that is only SuC V3 (250kW).
For SuC V2(150kW) my car reaches 42C before the charging.
With a complete preheating I think a supercharging session doesnt hurt that much.
View attachment 898573
We can se below from a research report that charging currents up to 1A at temperature 25C. (about 0.3C on these 2.8Ah 18650 NCA) will give about the same cycle life, so reducing below 0.3C or about 20-25kW will not reduce the wear noticable.
We can also see that a lower charging target clearly reduces the wear (less lithium plating). Tesla charge quite slow at high SOC anyway, probably to protect from lithium plating. It is anyway a good idea to not charge to a higher SOC than needed.
With Teslas Superchargers, the 3C is only present to about 20-25% SOC, over this the charging power reduces so we can probably assume a average between 2 and 3C. Remember that below is charging at high rates at 25C, and this we know is not warm enough to counter lithium plating. If we look at the wear as an average between 2 and 3C we will find that the wear is about double compared to slow charging For the 4.0V charging target (4.0V is about 80%). The battery will stand 500 cycles instead of 1000 cycles.
If we use a lower charging target than 4.0V / 80% the cyclic aging would probably reduce to less than double compared to the slow cxharging.
If we use a complete preconditioning the battery will be warm enough to reduce the most of the lithium plating, so the difference between slow charging and supercharging reduces further.
—> Stay low in SOC and precondition completely.
Remember that cyclic aging is not a very big part of the battery degradation for the first five years, so a small number doubled is till quite small.
View attachment 898574
I have some 30+ full charges and about 45 Supercharging sessions. Still my car shows a capacity that is very close to the calendar aging number. This means that the 45 Supercharging sessions that is about 17-18% of the total energy charged has not caused a noticable degradation to my cars battery. Of course, if I had not supercharged ever, and never charged full the battery capacity would be higher, but not with much as it is the calendar aging that takes the big bites even for my car that has quite low degradation.
One thing that might have helped my degradation from supercharging to stay low can be read below. I know this exists, there is some research reports that touch the subject but I havent dug into it.
As my car normally sleeps with 20-50% or so, and do use small cycles except when driving longer the battery probably get the regeneration we can read about below. There is numbers on this but I do not have the reports available here.
View attachment 898596
I would say that if supercharging when needed flor trips, and not every day we will not notice any extra degradation from this.
To reduce the wear:
-Preheat completely
-Arrive with low SOC.
-Better with two Supercharging sessions with 50% charging than one with 100%.
Remember that just having the car parked with 80-90% SOC most of the days for the first year will cause much more degradation than a lot of supercharging sessions.
Link to research report
I always preheat and I do not hesitate at all to supercharge. When needed I’m glad to.