The energy collected from the tiles cannot be stored as kinetic energy. what energy transformation is occurring within the tiles

In the most classical notation, we have two types of energy, Kinetic energy, is that one that the objects in the movement have usually is written as K = (m/2)*v^2

And the other type is the potential energy, this energy is the one "stored" that can be transformed into kinetic energy later, for example, an object that is lifted from the ground and remains in your hand has no kinetic energy, but it has potential energy.

Then, the energy in the tyles is stored as "potential energy", of course, this can be more specific, assuming that the tiles are solar tiles, the conversion is from thermal energy or radiation to potential energy (even more specific, if the energy is being stored in a battery, the transformation would be from thermal energy to chemical energy)