1) In Battery, go to options and set the number of stereo and mono outputs you want to use (upper right hand corner)

2) In Logic, set up an Audio Instrument and on the Inputs, there should be a menu called "multi channel" that detects Battery (and any other multi channel vst's you have). Make sure you select the Battery version under multi channel.

3) Create an aux object for any channels you want to use from Battery. For setting up a stereo channel for instance, choose Aux 1 as the channel, make sure the stereo button is clicked for the audio object and for the input, choose Battery 3-4 (1-2 is taken by the audio instrument channel Battery is assigned to). At this point, anything in Battery routed to the stereo 3-4 channels will play in the aux object, not the channel the vst is assigned.

4) Open battery and choose any cell. Then assign it to the 3-4 stereo channel by going to the bottom right hand corner of Battery and changing the output channel (do this by clicking and dragging it up so the values change). Once set to 3-4, click on the cell and the sound should come out the aux channel you set up in logic.