Disclosed herein are a
bus bar that simultaneously performs the
electrical connection between a plurality of unit cells and the detection of
voltage of the unit cells in a battery module having the unit cells mounted therein, wherein the
bus bar includes: vertical bent parts formed by bending opposite ends of a strip-shaped bar body in the same direction, respectively, the vertical bent parts being provided with
coupling grooves or protrusions; and a horizontal bent part formed by bending one of the vertical bent parts such that the horizontal bent part is parallel with the bar body, and a medium- or large-sized battery module including a plurality of unit cells, wherein the
electrical connection between the unit cells and the detection of
voltage of the unit cells are simultaneously performed using the
bus bar. It is not necessary to use additional connecting members for detecting the
voltage of unit cells when the bus bar according to the present invention is used in a battery module or a
battery pack. Consequently, the battery module or the
battery pack can be manufactured in a compact structure. Also, the
electrical connection and the mechanical
coupling are easily accomplished in
spite of the compact structure. Furthermore, the electrical characteristics, such as electrical resistance at connected regions after the electrical connection, and the
mechanical strength against external impacts or vibrations are excellent. In addition, it is possible to prevent occurrence of short circuits, which may be caused by a user or an operator, during a manufacturing process of the battery module or the
battery pack or during a maintenance process of the battery module or the battery pack.