This toy train moves with batteries.
Mom, look! The battery came off.
I’m heading to town to buy a battery for the robot dog I created.
A pond for electricity? May seem weird at first, but if you think of something that's gathering all the electricity into one pond... that thing is like a battery (and is a battery).
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.