Have a look at the integration tests here for some examples of how you can pass args to the script module:
If you have a lot of existing powershell maybe this is the way to go but be aware that you aren't really 'going with the grain' if you use ansible just as way of delivering a lot of custom powershell to your windows hosts.
It might be all you need of course, but its worth exploring if the existing modules and check mode, and the idempotency logic in the existing modules have any value for you.
Hope this helps,
Jon