Are you allowed to change a robot’s battery when it is taken out for broken robot or as a penalty? Thank you!
In short, the answer is generally yes.
With regards to the rules, when the robot is deemed damaged the 1.11 section applies, which says
If a robot is damaged, it has to be taken off the field and must be fixed before it can play again.
Further, if the robot is taken out as a result of the out-of-bounds rule, the section 1.10 applies, which says
Out-of-bounds robots can be fixed if the team needs to do so, as described in 1.11.
The whole question therefore boils down to whether replacing a battery does to some extend constitute fixing the robot. I personally believe that we can safely conclude that yes, it is indeed so.
Your question may also be viewed in a different way, which could be generally rephrased as “Does a robot need to use the same battery for one halftime”’? Given the current rules, the answer would be essentially the same as above: it does not, as the battery can also be replaced when the robot is damaged or out-of-bounds.
Hopefully, my response did help to clarify this a bit. If not, please feel free to ask some more questions.