The present disclosure provides a flexible battery, a circuit board and an electronic device, belonging to the technical field of batteries. The flexible battery of the present disclosure includes a flexible encapsulation structure, a plurality of battery cells and a crack detection wiring. The flexible encapsulation structure has a battery area and a peripheral area surrounding the battery area. The battery area includes a plurality of rigid areas and a plurality of bending areas alternately arranged along a first direction. The plurality of battery cells are arranged in a one-to-one correspondence with the plurality of rigid areas. In a corresponding rigid area, the battery cell is cladded in the flexible encapsulation structure. The crack detection wiring is located in the peripheral area and at least partially extends along the first direction. The crack detection wiring is cladded in the flexible encapsulation structure.