A rechargeable battery module is provided. The rechargeable battery module may include battery cells aligned in a first direction, a busbar holder configured to cover the battery cells while exposing electrode terminals of the battery cells, a busbar configured to connect the electrode terminals, and a flexible printed circuit connected to the busbar, covered with a film, and including a body portion including signal lines in the film, a sensor coupled to the busbar, a connection portion including a connection line connecting the signal line and the sensor in the film, and having a connection width, and a slot hole passing through the film along a perimeter of the sensor to define the connection portion, and having a penetration width.