EVENT single time battle good for bosses : In enemy encounter you can select what kind of back drop your monster battle has,
Map back drop: In the properties of the map you can change the battle back drop.
In battle event: go to monster groups. Make the trigger a switch or variable up to you. and have it in the main section change back drop. (problem with this is the background is seen switching over.)
Tile setting: go to the terran change what you want your back drop to be, then in the tileset set the number to be what you want it to be (you can copy a tileset and change the numbers IF you wish.)
Other than that no there is no way to my vast knowleage of how to change the battle background through for the tiles.