How to prevent informational messages from getting written when query results are output to a file
Apparently "someone" create a psqlrc.conf file that contains those messages you are seeing. 

You can prevent psql from loading psqlrc.conf by passing the parameter --no-psqlrc (or -X). To hide the any other messages use the --quiet (or -q) parameter. 

So your batch file should contain: 

"C:\Program Files\PostgreSQL\10\bin\psql.exe" --no-psqlrc --quiet --host localhost ...