[galderdi]

So you need about 40 Kwhrs for your range

170 Hp is 127 Kw - a 40 Kwhr battery should be capable of delivering that for a short period

Key point Duncan is making here 40Kwhr will be great for your range at moderate speeds 50-60mph. If you want your range at 150mph then you probably will need that 300Kwhr pack. I think the ideal target is somewhere in between. But 40Kwh is a common target, usually due to budget, weight and availability constraints.

The maximum voltage and current can't be answered in isolation.
It depends on the direction you choose. What motor and what controller. Then you specify your battery pack to target the upper limits of those two components.

Keep in mind the voltage and current limits of the battery are not necessarily the same as the volatage and current at the motor.

1. Once you have the desired voltage of the battery pack you divide it by the maximum voltage of the type of chemistry to know how many cells in series.
2. Then multiply the number of cells in series by their capacity (amphours) to get capacity of a single 'sting" in series.
3. Then divide your target capacity by the capacity of the single string in series to understand how many 'strings' of cells will be required in parrallel.

I hope that makes sense.

At a rough guess I think you should start looking at maybe 300v, 1000amps at the battery and more like 60Kwh to give you a buffer. I think 60Kwh is a better bet because to achieve the performance you are targetting you will end up with a heavier vehicle and VWs aren't the most aerodynamic cars.
I think your motor/s will need to handle around 2000amps for short periods to acheive that sort of speed....but I wouldn't be trying to hold those speeds for long. 2000amps for lets say 2minutes to get you to 150mph would mean motor system that handle around 1000amps continuous.