To remove the battery, flip the laptop over and remove the 8 screws from the base cover. Using a plastic scribe, pry the base cover from the recess points near the hinges.
Identify and unplug the battery cable. Loosen the 4 screws securing the battery to the system. Lift the battery up and away from the computer.
To reinstall the battery, place it back in the system and tighten the 4 screws to secure it. Reconnect the battery cable. Place the base cover back on the system and secure it with the 8 screws.