Circuit board, circuit board assembly and battery

The utility model belongs to the technical field of circuit board assembly, and particularly relates to a circuit board, a circuit board assembly and a battery. The circuit board comprises a substrate, first conductive pieces and a plurality of through holes, the first conductive pieces are arranged in the through holes, the through holes are used for placing the connecting terminals, and the first conductive pieces are electrically connected with the connecting terminals; the substrate is provided with a first surface, a second surface and a side face, the first surface and the second surface are oppositely arranged in the thickness direction of the substrate, the side face is connected with the first surface and the second surface, the through hole penetrates through the substrate in the thickness direction of the substrate, and the through hole is provided with an opening which is formed in the side face and faces the outer side. According to the utility model, the connecting terminal is placed in the thro