I was curious of thinking if it would be possible to double the voltage of a battery pack to reach the needs of a motor?
The use of a transformer for this purpose in an EV is nonsense, as already explained.
On the other hand, doubling battery voltage to allow the use of a relatively low-voltage battery with a higher-voltage motor is not only possible, it is in production and on the road in the most common "electrified" cars in the world: the Toyota Prius. The Prius system has an electronic (not transformer) voltage doubling stage in front of the inverter. This allows Toyota to run the battery at a voltage which is reasonable for the relatively small NiMH battery used in their hybrids, which running the motor-generators at a higher voltage suited to the speed ranges involved.
While it works well for Toyota in their hybrids, there is little point in doing this in a battery-electric vehicle. A rational design involves selecting a suitable operating voltage range for the motor and controller (inverter), and simply configures the battery with the appropriate number of cells in series to reach that target voltage.
