In order for a twisty light not to turn on, the battery cannot make electrical contact on both ends, which in most lights means no mechanical contact either. So it rattles back and forth. Some lights solve this by putting a foam washer with a hole cut in the middle on one end of the battery. So the foam always keeps pressure on the battery and it doesn't rattle. When the head is screwed down, the foam compresses, the positive nipple on the battery pushes through the hole in the foam washer, and the battery makes electrical contact on both ends.

Another way to eliminate 95% of the rattle is to wrap the battery with a yellow sticky note. Cut the note to the proper size to be the length of the battery, stick it to the battery, and wrap it around. It it's to large while fully wrapped to fit into the tube, cut off the end of the wrap so it's wrapped less fully. Get it to where it barely fits inside the tube, but with enough friction to hold it in place. That kills most of the rattle.