Flexible circuit board, battery and electric device

The utility model discloses a flexible circuit board, a battery and an electric device. The flexible circuit board is used for being connected with the battery monomers to collect signals. The flexible circuit board comprises a body and a connecting part. The body comprises a buffering part, the buffering part extends in a circuitous mode in the length direction of the body and forms a multi-layer structure stacked in the thickness direction of the body, and the buffering part is configured to be capable of extending in the length direction of the body so as to prolong the length of the body. The connection part is connected to the body and can be connected to an electrode terminal of the battery cell. The buffer part can extend along the length direction of the body so as to at least partially unfold the stacked multi-layer structure along the length direction of the body, so that the length of the body is prolonged, and the length variation of the flexible circuit board due to the length increase caused by