aemeijers writes:
Take a flashlight and look down alongside the battery, and see if the
tray is painted metal or plastic covered. If painted metal, and you
see rust when you peek down there, good idea to pull the battery and
repair as needed. (paint, reinforcement, etc.) It can ruin your whole
day if you are driving down a bumpy road, and the rusty hold-down bolt
breaks, and the battery bounces and shorts out against the inside of
the hood. BTDT.

Wow - that sounds quite unlucky - so just out of curiousity what were
the symptoms and results you observed from the broken-free battery and short?