While fast charging there are two things that should never happen:
- The battery must not overheat.
- The battery should never be overcharged.
The first point just needs a adiquit cooling system. The second point is solved by the BMS just as you prevent your glass from overflowing when filling it with your drink. Just before it gets full, you are starting to eat less and less.
When fast loading it is practically the same. Only that not one glass after another is filled, but all Glöser at the same time. The BMS must make sure that not a single cell is overloaded when fast loading.
For the long haul that means:
At the latest at 80% you should stop charging and continue driving. At least if you want to be time efficient. Overall one more charging stop is more time efficient.