Hmm. I’ve never had that happen to me before. What camera are you using? and what type of battery? Have you ever had this happen before? or anything similar? Is it a new battery? or perhaps a battery that wasn’t intended for that type of camera? Is there a built in lever that helps hold in the battery? Also, do you know how long the battery has been in there?
Answers to some of these questions will help a lot in determining a solution!