How to exclude a folder in 7zip?
As tested on my system:
7zip a -t7z -mx0 -x!test\* test.7z c:\temp\
If you're in the source directory, the files are stored with relative paths, so the test folder looks like test\file1.txt, not c:\temp\test\file1.txt.
Please note, with the -mx0 switch, you're not compressing the files, only copying them fullsize into the archive.