On Windows, default terminal for Atom\'s Platformio-Ide-Terminal is Powershell (at least, that is what I get without any configuration).
I would prefer a terminal using
Set the default shell in: Edit>>Settings>>Packages>>Platformio Ide Terminal>>Settings>>Shell Override
You can use the git's bash as proposed here as you probably already have git installed.
C:\Program Files\Git\bin\bash.exe