You don't understand what the BMS does.
Once again: You don't charge cells. You charge a battery. The BMS knows something about the cells and is charging them accordingly.
You plug in, come back later and it's charged. You don't need to care about cells.
Here was me thinking that I'd replied to this. Must have been in preview when my PC crashed. It's been doing that a lot in the heat here.
In very brief.
When you drain a pack to 2%, the BMS has no option, almost all of the cells are discharged and almost all the cells have to be re-charged. At this point there is no BMS wizardry to be had, it dumps massive power into the pack to 50% then starts to taper the power off. This is how the cells charge.
Where a BMS comes in is around the cooling system, how it keeps the pack balanced when charging and when it is charging/discharging cells where the BMS can keep higher power cells at lower charge rates (say 70%), whilst pushing the more discharged cells to charge more rapidly.
At 2% this doesn't happen.
When racing around the country charging to 50% (fastest charge time), then discharging to around 2%, then keeping on doing this, the BMS is only managing the parallel charge at high rates and keeping the heat down.
This is not magic. The BMS, when used in this way, does not protect from pack degradation. It can't.
Push this forward and you get a situation which has been long known with people who are at the limit of their spending. At the beginning of the month, they fill their vehicle fully and keep it full. At the end of the month they use that fuel and keep the level low whilst topping it up with small amounts.
In an ICE that doesn't matter, in an EV that does.
Perhaps charging contracts will help level the cost, balance payments and allow people always to keep the vehicle charged. But, initially, they will be expensive so don't be on it.
EV is emerging technology. We have been living with the ICE for over 100 years and we know it's faults and issues well. Time will tell with EV's, but simply blowing off concerns because less than a million Tesla vehicles haven't shown more than a few % of battery pack issues is not the way to go.
At the turn of the last century the "horseless carriage" owners were enthusiasts. They would have told you very little ever went wrong but they drove with a full toolbox, lubricants and spare parts to ensure they made their journey.
Wind forward 100 years to the EV world and little has changed. The early adopters want to know about their technology, how to drive it to eke out the very best and how to ensure the best longevity.
The rest of the people who will buy them, in the decades to come? They're just going to be drivers or, as we Army mechanics called them, "sophisticated aiming devices". They won't care about the technology or the best way to use it, just as people, today, don't get the very best out of their ICE. Because they don't care.
I passed all my driving tests in Germany, drove the first 5 years of my driving life on the Autobahns and am not what you call a "slow" driver. Yet when my work had an awareness day for fuel conservation, I won the simulation MPG drive by a mile.
That kind of knowledge is not going to be there for the later EV take up and all that this kind of attitude is going to do is build up bad press at a critical point in EV transition. NO, the BMS is not the god of pack protection, it is a tool and it needs someone to use it wisely. Saying that it has a BMS and that is all you need to know is not a winner in my experience.
On the ++ side, Tesla has the best technology on the market, the best systems, the best range and the best record on pack life.
Why avoid just a little bit of caution and be adamant that you can just do what they hell you like with the car and it will all be OK because it has a BMS? Because it won't. That pack is full of Li+ cells and they have two usage patterns. One which leads to destruction and one which leads to a long and healthy life. Whilst the BMS will reduce the abuse and maximise the life, no matter how it is used, it is not omnipotent. It has to work within the restrictions of the technology it manages.
This is all I'm saying. Nothing more.