Electrochemical reactions occur only in the cell zones. Which means, cells must come under active components list. On the other hand, all other zones including the heat carrier plate should be considered as passive components.
Check this section of the User's guide for more information: 28.2. Using the MSMD-Based Battery Models (ansys.com)
If you are not able to access the link, refer to this forum discussion: How to access the ANSYS Online Help