Use 6mm2 cables of good quality like Mega or Caramay. Each phase will use a 32A breaker to provide 7kw per phase.
Theoretically 4mm2 cables are enough to handle a max of 32A but in reality your future EV could potentially charge for long hours at close to the peak 32A, so it is better to use 6mm2.
General household single appliance will never pull 32A (let alone continuously for more than an hour), but an EV could pull that for a few hours depending on the charging curve of the car.