BMW Repair Questions? Ask a Mechanic for Answers ASAP
When an Electric or Hybrid Vehicle is Serviced a Battery Health Check Report should be produced at the time. This will detail the health of the battery and if there are any potential problems.
Unfortunately Electric and Hybrid Vehicles are still to new to be able to give any real advice on the longevity of t he battery but obviously with age the battery will degrade and will never be as good as a new one.
On a 2018 vehicle if it has a reasonably low mileage I wouldn't think you would have to many issues. If you were looking at something of say 10 years old or high mileage of say 100000 miles plus then you potentially could have some issues with battery life.