Because the time taken to charge 200 little batteries in parallel is the same as it is to charge them in series.
Smaller batteries are capable of delivering less current, but also only capable at charging at lower currents. So you can’t charge the individual cells in a battery any faster than the battery as a whole.
If you tried to take a single little cell, and charge it at power level of an entire EV battery, all you’ll get is a small explosion and a fire. If you take one of the individual cells out of a Tesla, it’s not much bigger than a AA battery. The charging cable of a super charger is much thicker than a AA battery, and made out of a substantial better conductor than a battery. Just imagine what would happen if you took a battery the size of a AA cell, and plugged it straight into that cable, running at 480V and pushing almost a thousand amps. They peak at 250kW, about 50 households of power usage. Your little battery won’t stand a chance.
Smaller batteries are capable of delivering less current, but also only capable at charging at lower currents. So you can’t charge the individual cells in a battery any faster than the battery as a whole.
If you tried to take a single little cell, and charge it at power level of an entire EV battery, all you’ll get is a small explosion and a fire. If you take one of the individual cells out of a Tesla, it’s not much bigger than a AA battery. The charging cable of a super charger is much thicker than a AA battery, and made out of a substantial better conductor than a battery. Just imagine what would happen if you took a battery the size of a AA cell, and plugged it straight into that cable, running at 480V and pushing almost a thousand amps. They peak at 250kW, about 50 households of power usage. Your little battery won’t stand a chance.