Voyager separates in The Eternal Tide
- but that's after a substantial refit in Full Circle
, equipping the ship with a slipstream dive and all the latest novelverse gizmos.
As for series-Voyager, there IS a battle bridge on the MSD diagram, but the writers never paid any heed to it (it has two warp cores, two computer cores and two navigational deflectors, but episodes of the show make it explicitly clear there is only one of each)
See huge, detailed MSD diagram here