3DR GPS Lea6 v1.1 with APM 2.5

After a crash, I notice the battery has come loose from the board, but the battery is still attached to the strap on the top. I taped it down for now. I started up the APM with GPS, and all works. What is the battery for? Can I live with out it? How do I permanently fix it to the board??

Thanks, Brian

The battery is for the onboard volatile memory that is used to store the satellite almanac which allows for a shorter cold/warm startup. If the battery is not connected properly to the pwb, the volatile memory will not be sustained when the GPS is not powered by the APM.
TCIII Developer