A series of tests yielding a single total score, used for measuring aptitude, intelligence, personality, etc. (Webster's Third New International Dictionary, 1993)
A set of one or more observations identified as by a single name and code, treated as a shorthand unit for ordering or retrieving results of the constituent observations. A battery can be a single observation, but also a superset of batteries
A test battery is a set of several tests designed to be administered as a unit. Individual subject-area tests measure different areas of content and may be scored separately; scores from the subtests may also be combined into a single score.