(disclaimer: I am no battery expert!)
DCIR (cell internal resistance) is one of the primary limitations in cell performance.
Fundamentally it is this that creates the heat in the cell when current is drawn.
It also typically increases as cells age.
VAG/VW/Porsche et al have clearly chosen fast charging as the one parameter that they intend to compete with and try tyo best Tesla by offering higher charge rates. Higher charge rates do not necessarily equate to faster charging of course as Tesla's are typically more efficient so actually usually add more miles of range per minute.
Tesla afaik currently use NCA chemistry for their cells, everyone esle uses NMC.
So is it NMC that allows for faster charging?
There are innunmerable variations in chemistry of course, but what is the probability that the VW Etron can charge at a substantially higher rate than the MB EQC? I find it implausible that VW have access to such a substantial technology improvement over MB particularly when using external cell suppliers.
Another factor is curious. VW are clearly sandbagging their overal range significantly in the form of reportedly a large "buffer". Why would they do this? Surely the only answer can be that they know there will be heavy degradation and bascially have to hide it in this buffer, so the owner does not see an excessive loss in range, however the buffer is used up over time.
Have VW cynically calculated that they would rather "beat" Tesla on one metric, and advertise that massively, even at the expense of losing on another, rather then lose slightly on all metrics.
Back to the first point though is that DCIR will increase over time as cells age. Range and buffer discussion aside, this must mean a reduction in performance vs age in order to manage cell temperatures.
So if VAG/VW/Porsche are charging their cells super aggressively does this mean that their vehicle performance will decrease with age more rapidly than a Tesla? Only scientific tests on the actual cells in the respective vehicles would truly answer this but many reports on NMC as used in EVs suggest that the cells degrade significantly with high C rate charging.
example:
Fast-charging effects on ageing for energy-optimized automotive LiNi1/3Mn1/3Co1/3O2/graphite prismatic lithium-ion cells - ScienceDirect
Tesla have the track record to show the long term durability of their packs with supercharging although they too have had to manage it, VAG/VW/Porsche just might be pushing their luck here and hoping for typical use and early limited high power charger availability not to expose this weakness and for steady iteration to relegate initial models to the history books. They most certainly are capable of making such an cynical calculation.
DCIR (cell internal resistance) is one of the primary limitations in cell performance.
Fundamentally it is this that creates the heat in the cell when current is drawn.
It also typically increases as cells age.
VAG/VW/Porsche et al have clearly chosen fast charging as the one parameter that they intend to compete with and try tyo best Tesla by offering higher charge rates. Higher charge rates do not necessarily equate to faster charging of course as Tesla's are typically more efficient so actually usually add more miles of range per minute.
Tesla afaik currently use NCA chemistry for their cells, everyone esle uses NMC.
So is it NMC that allows for faster charging?
There are innunmerable variations in chemistry of course, but what is the probability that the VW Etron can charge at a substantially higher rate than the MB EQC? I find it implausible that VW have access to such a substantial technology improvement over MB particularly when using external cell suppliers.
Another factor is curious. VW are clearly sandbagging their overal range significantly in the form of reportedly a large "buffer". Why would they do this? Surely the only answer can be that they know there will be heavy degradation and bascially have to hide it in this buffer, so the owner does not see an excessive loss in range, however the buffer is used up over time.
Have VW cynically calculated that they would rather "beat" Tesla on one metric, and advertise that massively, even at the expense of losing on another, rather then lose slightly on all metrics.
Back to the first point though is that DCIR will increase over time as cells age. Range and buffer discussion aside, this must mean a reduction in performance vs age in order to manage cell temperatures.
So if VAG/VW/Porsche are charging their cells super aggressively does this mean that their vehicle performance will decrease with age more rapidly than a Tesla? Only scientific tests on the actual cells in the respective vehicles would truly answer this but many reports on NMC as used in EVs suggest that the cells degrade significantly with high C rate charging.
example:
Fast-charging effects on ageing for energy-optimized automotive LiNi1/3Mn1/3Co1/3O2/graphite prismatic lithium-ion cells - ScienceDirect
Tesla have the track record to show the long term durability of their packs with supercharging although they too have had to manage it, VAG/VW/Porsche just might be pushing their luck here and hoping for typical use and early limited high power charger availability not to expose this weakness and for steady iteration to relegate initial models to the history books. They most certainly are capable of making such an cynical calculation.
