Sony VGN-BX500 - Manual (Page 22)

22 n N
Getting Started
3 Slide the battery diagonally into the battery compartment until the projection (2) at either side of the battery compartment
fits into the U-shaped cut (3) on the respective side of the battery.
4 Rotate the battery in the direction of the arrow, and push the battery down into the compartment until it clicks into place.