OK my account got banned a while ago not because of me so I wanted to ask if I will buy another account of battlefield 4 

will it get banned too because of my IP?

I am talking about an account from 3 years ago

That's the BF4DB Ban Policy which affects you/your further accounts:

Linked Accounts:

• Accounts having overlapping IP and timestamp information will be considered a linked account. Player information streamed to the Service can be used for this purpose.

• If an account is currently banned by BF4DB, all other accounts that are positively identified as a linked account will receive a ban for “Linked Account” as well. Similarly, if the main ban successfully appeals, all other alt bans will be lifted.

• Accounts having the same Gravatar will be considered linked, and treated appropriately. 

  So yes.. you are kinda IP banned.. 

  They also wrote a Statement about "Hacked" accounts.

  
  

  (P.S. : if you are truhly innocent and find a nice server admin, he may put you on the whitelist for his server.. otherwise you can still play 》official《 servers.)