> if in average you have 2 cars charging for 5 minutes every hour, you can draw 166kW continuously instead of having bursts of 1MW consumption)

You definitely need to have that to not load the grid with 1MW, but the question still remains what the capacity of the battery is. A charger that promises a 5 minute 1MW charge BUT which can only do it once per hour and then falls back to 200kW doesn't seem as special as a charger that actually charges a car every five minutes.

It's convenient to get going in 5 minutes. But the time you REALLY want the charger to be quick is when you are third in line to charge at that charger.

I was definitely using simplifying assumptions to get my point straight here.

Setting the actual parameters for such systems is an engineering job, I just wanted to illustrate that the goal isn't going to have the charging station off the grid during peak hours thanks to the batteries, and more about managing the burden you put on the grid.