The first image shows a general view of the vacuum cleaner. The battery pack is removed by pressing the green buttons and pulling downwards. The four stripes by one of the green buttons are the LED's which flash when charging, and when all four are lit the battery pack is fully charged.

The second imaged shows the removed battery pack. Undo the four screws at each corner with a Torx10 screwdriver. Note screws at the bottom corners are longer. Pull off the lid and the green buttons can also be removed.