[Al Skierkiewicz]

yassi,
I normally would recommend against this for a few reasons. If you are controlling the motion of the battery carrier you have to be careful to keep shocks to the case at a minimum. Hard hits can damage battery internals.
Secure mounting takes on new meaning when the battery motion can exceed the speed of the robot. Inspectors will be watching for battery mounting in these situations.
Any motion will require that the wiring to the battery be extended. This brings up special issues. If you splice wires to make them longer, then the splice must be secure and insulated. Added wire length will affect maximum current. Figure at 100 amps, every 2 feet of #6 will drop an additional 0.1 volts. Typical currents during pushing or hard driving will drop 4 times that. Make sure to account for the length of both the red and black wiring.
The last thing is you need to consider the possibility of the wiring getting caught in the moving mechanism and causing a short to the robot frame should the wire insulation get damaged.
The appropriate robot rule on this question is you may only have 1 foot of wire attached to the battery. All other wiring must be counted in the weight of the robot.
Teams have used the battery to change robot center of gravity in the past.