Yes, BATTERY is a Scrabble word!

Letter values in Scrabble US: B 3, A 1, T 1, T 1, E 1, R 1, Y 4.

Is it a valid word?

BATTERY is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

group of guns or missile launchers operated together at one place
a device that produces electricity; may have several primary or secondary cells arranged in parallel or series
a collection of related things intended for use together
a unit composed of the pitcher and catcher
a series of stamps operated in one mortar for crushing ores
the heavy fire of artillery to saturate an area rather than hit a specific target
an assault in which the assailant makes physical contact

Also: electric battery, stamp battery, barrage fire, assault and battery.