Plug (Not Maintenance-Free As Well As AGM-Batteries)
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Volvo S80, 2005 Volvo S80, 2004 Volvo S80, 2003 Volvo S80, and 2002 Volvo S80. However, it is still accessible from the selected car via links, so may be relevant.
On top of the battery is a cover with six plugs, one for each cell. The plugs can be opened when checking and topping up the electrolyte.