If you are familiar with the publish or batch plot function of autocad. The following trick will help you batch plot to plts.
Set up a printer/plotter as you normally would in autocad. Then go into the properties of the printer under the ports tab and switch it to PLOT TO FILE.
Now you should have a printer specifically set to 'Plot to File' and you would use this printer/plotter instead of your normal printer/plotter.
Good luck