Microsoft solution to automate backup on SQL Express
NB: SQL Server Agent is not available on this SQL release
Microsoft Solution https://support.microsoft.com/en-us/kb/2019698
Sample Backup.cmd file
sqlcmd -U sa -P xxxx -S .\SQL2012EXPRESS -Q “EXEC sp_BackupDatabases @backupLocation = ‘C:\SQLBackups\’, @backupType = ‘F'”
You can schedule jobs with standard “Windows Jobs“