Creating a crontab ucs automated backup

We are attempting to use the crontab on our F5 Viprion setup for all Hosts and guests to generate an automated backup and send this backup to our backup storage server. I have the below script and it is working, but I am not sure how to include the password for the SCP client so the backup will be moved to the server.

tmsh save /sys ucs /var/local/ucs/$(/bin/hostname).ucs && scp /var/local/ucs/$(/bin/hostname).ucs username@xxx.xxx.xxx.xxx:/$(/bin/hostname)-$(date +\%Y-\%m-\%d).ucs

Username and IP address have been modified for security purposes.