there is no need to run a batch process. Create a Model empty then reference into it the models that you wish to publish. then in windows create a txt file that has four lines:
publishdgn publishreferences on
publishdgn forcerepublish on
publishdgn publish
Exit
then create a Bat file that has the following lines:
@echo off
call "C:\Program Files (x86)\Bentley\imodelcomposer V8i\imodelComposer\imodelComposer.exe" -s(directory and name of txt file) (directory and name of DGN file)
Make sure that you edit to input your txt, and dgn file named.
Then use Windows scheduling (Task Scheduler) to setup the times that you want to process the batch file.