The electric storage medium battery was coined by American polymath Benjamin Franklin in a 1749 letter describing his apparatus of a bunch of Leyden jars all connected together, by analogy with a battery of guns. Artillery batteries have been called that since the 1550s because they inflict battery on a targeted fortress or castle. That violent battery, the latter half of assault and battery, was borrowed from French as legal vocabulary in the 1530s, not much earlier.
Middle French batterie was derived from the verb batre, meaning “beat”. Old French batre descends from Latin battuō, also meaning “beat”. Latin battuō is likely a borrowing from Gaulish, the Celtic language spoken in France before its Roman conquest.