This hasn't been confirmed yet and the news came from Motor.es anonymous sources, so it may no come to pass. Seems like there may be plans for a zero-emissions i1 and it could share a platform with the Mini Cooper Electric that's expected to come out in 2019. Since BMW already trademarked the i1 badge, they may as well use it.
https://www.motor1.com/news/238713/bmw-i1-electric-planned/
https://www.motor1.com/news/238713/bmw-i1-electric-planned/