A battery module comprising: a cell assembly comprising a plurality of secondary batteries having an electrode lead formed in a shape protruding in a front-and-back direction and stacked on each other in a left-and-right direction; and a bus bar assembly configured to provide electric connection between the plurality of secondary batteries, wherein the bus bar assembly comprises: a first insulating frame where one or more insertion portions perforated from a back surface to a front surface are formed such that a plurality of electrode leads are inserted and comprising an electric insulating material; a second insulating frame mounted on the front surface of the first insulating frame and comprising an electric insulating material; a first bus bar mounted on the first insulating frame, contacting one of the plurality of electrode leads inserted into each of the one or more insertion portions, the one electrode lead being located at one end of the plurality of electrode leads, and comprising an electric conductive material; and a second bus bar mounted on the second insulating frame, contacting one of the plurality of electrode leads inserted into each of the one or more insertion portions, which is located at the other end, and comprising an electric conductive material. a cell assembly comprising a plurality of secondary batteries having an electrode lead formed in a shape protruding in a front-and-back direction and stacked on each other in a left-and-right direction; and a bus bar assembly configured to provide electric connection between the plurality of secondary batteries, wherein the bus bar assembly comprises: a first insulating frame where one or more insertion portions perforated from a back surface to a front surface are formed such that a plurality of electrode leads are inserted and comprising an electric insulating material; a second insulating frame mounted on the front surface of the first insulating frame and comprising an electric insulating material; a first bus bar mounted on the first insulating frame, contacting one of the plurality of electrode leads inserted into each of the one or more insertion portions, the one electrode lead being located at one end of the plurality of electrode leads, and comprising an electric conductive material; and a second bus bar mounted on the second insulating frame, contacting one of the plurality of electrode leads inserted into each of the one or more insertion portions, which is located at the other end, and comprising an electric conductive material. a first insulating frame where one or more insertion portions perforated from a back surface to a front surface are formed such that a plurality of electrode leads are inserted and comprising an electric insulating material; a second insulating frame mounted on the front surface of the first insulating frame and comprising an electric insulating material; a first bus bar mounted on the first insulating frame, contacting one of the plurality of electrode leads inserted into each of the one or more insertion portions, the one electrode lead being located at one end of the plurality of electrode leads, and comprising an electric conductive material; and a second bus bar mounted on the second insulating frame, contacting one of the plurality of electrode leads inserted into each of the one or more insertion portions, which is located at the other end, and comprising an electric conductive material.