The invention relates to the technical field of circuit boards, and particularly provides a circuit board
assembly for a battery device, which comprises a circuit board main body, a
branch structure and a fixed plate. The circuit board main body comprises a plurality of parallel wires, the
branch structure comprises a
branch connecting part and a sampling part, and the sampling part is used for collecting battery information; the branch connecting part is provided with through holes, and a
welding spot is formed in at least one through hole and is welded with a wire; the fixing plate is connected with the branch connecting part, the width of the fixing plate is W1, the
diameter of the through hole is R, and R / W1 is larger than or equal to 0.01 and smaller than or equal to 2. In the invention, the branch connecting part is welded on the circuit board main body wire through the
welding spot through hole and is reinforced by using the fixing plate, so that the situation that the branch connecting part is bent and warped due to heating during
welding is avoided; besides, the ratio of the
diameter of the through hole to the width of the fixing plate is properly designed, so that the branch connecting part can be sufficiently fixed, bending and even folding are eliminated, welding is firm, and large local resistance is avoided.