The batteries are bonded to the printed circuit board that also contains the charging system, the contacts for the switch and the motor controller. A printed circuit board is a thin piece of fiberglass with copper wires etched on it's surface (we also saw a PCB in the remote control we took apart).
There is also a very tiny auxiliary PCB that holds the 2 LEDs. These LEDs indicate that the battery needs recharging, that the razor is on or that the razor is recharging.
The business end of the razor consists of three rotating blades. The blades engage on three shafts, all of which mesh with the motor's gear in a direct-drive system.