In a busbar assembly, a first busbar subassembly includes a first transmission unit having a first transmission busbar with a uniform width, and a first output unit having a first output busbar with a uniform width. One of the first transmission unit and the first output unit has a bent structure with a bend line perpendicular to a line of a lengthwise direction thereof. A second busbar subassembly includes a second transmission unit having a second transmission busbar with a uniform width, and a second output unit having a second output busbar with a uniform width. One of the second transmission unit and the second output unit has a bent structure with a bend line perpendicular to a line of a lengthwise direction thereof.