Dear Giovani,
The number of batteries in your system will depend on the battery pack you are using, and how many cells each battery pack contains.
Given the specifications you provide:
To provide 2 hours of storage at full capacity for a 5 MWh battery, set the desired bank capacity to 5000 kWh, and the desired bank power to power to 2500 kW. Then set the desired bank voltage to 96 VDC. You can then look at the "Computed Properties" under "Current and Capacity" to see the resulting parameters to confirm that they are reasonable for your system. Given the default values in SAM, those specifications result in a battery bank of 27 cells in series and 22,862 strings in parallel for a total number of cells of 617,274. If you know the number of cells in each battery pack, you can calculate the equivalent number of battery packs.
Best regards,
Paul.