I'm not from that team, so the following is an educated guess from watching the video.
That looks for all the world like an
IFI Wheel from Vex Robotics. I'd guess 8" diameter and 2" wide. You can see the wheel is being direct driven by a CIM powered
Andymark Stackerbox. The stackerbox has a 3.57 ratio, so that's an 8" wheel turning at around 1500 RPM, for a surface speed of around 50 feet per second. What I can't tell is how much compression on the ball that they're running...