Yes, the balls do need charging for an internal energy source (i.e. a battery).
This battery is what powers some of the electronics and sensor equipment inside the ball, and of course the radio equipment used to send that data out for FIFA's video assistant referee to use.
From the manufacturer, adidas,
- Connected ball technology comes to Al Rihla for sport’s biggest stage, providing the VAR team with precise ball data in real time to support fast and accurate offside calls
- A new adidas Suspension System will allow for the most time-precise motion sensor to ever be used inside a World Cup Official Match Ball, tracking every touch of the game at a rate of 500 times per second
- The 500Hz inertial measurement unit (IMU) motion sensor inside the ball will enable the collection of very accurate ball movement data and transmission to Video Match Officials within seconds throughout the tournament
A new adidas Suspension System in the center of the ball hosts and stabilizes a 500Hz inertial measurement unit (IMU) motion sensor, which provides unprecedented insight into every element of the movement of the ball, while making this technology unnoticeable for players and not affecting its performance whatsoever. The sensor is powered by a rechargeable battery, which can be charged by induction.