Just read up on the model, I think I have an answer, if not a colleague (who uses the PEMFC module) is checking.
https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v231/en/flu_ug/flu_pemfc_chap_pem_using.html
Click on Help in Fluent, then paste the link into the browser, you want the limitations section.
You are navigating away from the AIS Discovery experience