Windows batch and PowerShell passing variables issue.

If I use variable instead of number as build version value, it is not working.

Any suggestion?


Batch Script:
------------

set BuildVersion = 2.1

cd C:\Scripts

powershell.exe -file Deploy-Axsis.ps1 %BuildVersion% (Not working)
powershell.exe -file Deploy-Axsis.ps1 2.1 ( Working) 



PS Script:
----------

$buildVersionMain=$args[0]



Error:
-------
The variable '$buildVersionMain' cannot be retrieved because it has not been set.