I put in new FL40 battery but didn't have the attached black object with the outlining orange circuitry and plug shown in several of the photographs. After considerable online research I discovered it was a NFC antenna for easily transferring data between two very close devices, not an inductive charging coil that I believe other commenters alluded to. This antenna can be carefully removed from its black adhesive backing on the original battery and then attached at the same location on the replacement battery using double-sided tape. The antenna's plug is then attached to the same connection it was detached from when the original battery was removed. Hopefully NFC will still function.