A busbar assembly of a battery module, comprising a first busbar, a second busbar and a first insulator; the first busbar comprising a first connecting portion, a second connecting portion and a first main portion, the first connecting portion being capable of being connected to a first battery unit, the second connecting portion being capable of being connected to a second battery unit, the first main portion connecting the first connecting portion and the second connecting portion; the second busbar comprising a third connecting portion, a fourth connecting portion and a second main portion, the third connecting portion being capable of being connected to a third battery unit, the fourth connecting portion being capable of being connected to a fourth battery unit, the second main portion connecting the third connecting portion and the fourth connecting portion; in a height direction, the first main portion and the second main portion being partially overlapped with each other, and the first insulator insulating the second main portion and the first main portion; the first battery unit, the third battery unit, the second battery unit and the fourth battery unit being capable of being arranged sequentially in a longitudinal direction; characterized in that the first connecting portion, the third connecting portion, the second connecting portion and the fourth connecting portion are sequentially arranged and spaced from each other in the longitudinal direction; the first connecting portion and the second connecting portion are positioned at the same side with respect to the first main portion in a transverse direction, the third connecting portion and the fourth connecting portion are positioned at the same side with respect to the second main portion in the transverse direction. the first busbar comprising a first connecting portion, a second connecting portion and a first main portion, the first connecting portion being capable of being connected to a first battery unit, the second connecting portion being capable of being connected to a second battery unit, the first main portion connecting the first connecting portion and the second connecting portion; the second busbar comprising a third connecting portion, a fourth connecting portion and a second main portion, the third connecting portion being capable of being connected to a third battery unit, the fourth connecting portion being capable of being connected to a fourth battery unit, the second main portion connecting the third connecting portion and the fourth connecting portion; in a height direction, the first main portion and the second main portion being partially overlapped with each other, and the first insulator insulating the second main portion and the first main portion; the first battery unit, the third battery unit, the second battery unit and the fourth battery unit being capable of being arranged sequentially in a longitudinal direction; characterized in that the first connecting portion, the third connecting portion, the second connecting portion and the fourth connecting portion are sequentially arranged and spaced from each other in the longitudinal direction; the first connecting portion and the second connecting portion are positioned at the same side with respect to the first main portion in a transverse direction, the third connecting portion and the fourth connecting portion are positioned at the same side with respect to the second main portion in the transverse direction.