The roomba achieves this through rather large contact pads on the base of the charger, which scaled up to car-size would be about 50cm across. What happens when

The roomba achieves this through rather large contact pads on the base of the charger, which scaled up to car-size would be about 50cm across. What happens when my cat walks under my car and onto a large metal plate with a few kW of power flowing through it?