Yes, in order to open a second account, you must have a valid and up-to-date National Identity Card (DNI) or Foreign National Identity Card (NIE) in our systems.
If you need to update your National Identity Card (DNI) or Foreign National Identity Card (NIE) number, log in to your online banking from the Banco Sabadell website, open the drop-down menu next to your name and go to My Profile. Next, click on My Personal Data and then on Identity Document.