Found in Metroid II: Return of Samus and essentially the precursor to the Missile Stations of subsequent games, the Missile Battery reloads all Missile ammo upon contact. However, unlike the aforementioned Missile Stations, these exceptionally large missile canisters are usually found in remote locations within the regular playable area. In Phase 1, the Star Ship contains a Missile Battery and a Big Energy Ball.
Metroid II manual
"Reloads all missile pods to maximum."