When Payment reference ("Other Info" tab on customer invoices) has a value (i.e. invoice number), then the bank account / bank name is printed on customer invoices

Payment Communication: 000000000000000000002500264 on this account: XX12 3456 7890 1234 5678 9 - Bank Name

field partner_bank_id has the bank account number and the bank name

For most payments, it is important to also provide the BIC. While it has been many times suggested to add bank details to the footer,  Odoo offers the option to have variable bank details added to the invoice, which is useful if you use different bank accounts (i.e. in different currencies and/or countries). 

How can I achieve to have the BIC added to the partner_bank_id field ?