How to disable the output of 7-Zip?

Just add > NUL: to the end of your command.

You can use the -bs command to control where output goes. To stop anything but error output, I would add -bso0 -bsp0.

It is highly recommended to view status messages in the process. To avoid long messages, display only confirmations:

...\right_path\7z a output_file_name.zip file_to_be_compressed | findstr /b /r /c:"\<Everything is Ok" /c:"\<Scanning" /c:"\<Creating archive"