A battery module, comprising: a cell stack formed by stacking a plurality of pouch-type secondary batteries having electrode leads on each other; and a bus bar assembly (200A-200D) configured to electrically connect the plurality of secondary batteries to each other and including a connection bus bar contacting two or more of the electrode leads of the cell stack, and a coupling bus bar coupled to the connection bus bar, wherein the connection bus bar and the coupling bus bar have a bar shape extending in an upper and lower direction, and each of the connection bus bar and the coupling bus bar include a front surface, a rear surface and side surfaces, wherein the upper and lower direction is a direction in a length direction of the connection bus bar and the coupling bus bar, a direction in a width direction of the connection bus bar and the coupling bus bar is a left and right direction which is the stacking direction, and a direction in a depth direction of the connection bus bar and the coupling bus bar is a front and rear direction (F-direction), wherein the connection bus bar includes at least one insert groove formed so that a bent end portion of at least one of the electrode leads is inserted therein, the insert groove is formed at a front surface of the connection bus bar, the insert groove has a structure recessed from a front end to a rear end of the connection bus bar, and a recessed depth (D1-D4) of the insert groove (212, 212B1, 212B2, 212C, 212D) is equal to an entire thickness (T1-T4) of the at least one electrode lead inserted into the insert groove (212, 212B1, 212B2, 212C, 212D) in an inserting direction, and the rear surface of the coupling bus bar is formed to press the contacted electrode leads, wherein the bus bar assembly (200A-200D) further includes a bus bar frame having a front surface on which the connection bus bar is loaded, the bus bar frame being located between a front portion of a body of the secondary battery and a rear portion of the connection bus bar, wherein the bus bar frame is configured to have a perforation hole through which the electrode lead of the cell stack passes, or so that the electrode lead passes by the side portion of the bus bar frame and protrudes forwards, wherein the bus bar assembly (200A-200D) further includes a fastening member configured to couple the connection bus bar and the coupling bus bar to each other, and wherein the fastening member further includes a fastening bolt inserted through the connection bus bar and the coupling bus bar, and a cylindrical rod of the fastening bolt is inserted and fixed in the bus bar frame. a cell stack formed by stacking a plurality of pouch-type secondary batteries having electrode leads on each other; and a bus bar assembly (200A-200D) configured to electrically connect the plurality of secondary batteries to each other and including a connection bus bar contacting two or more of the electrode leads of the cell stack, and a coupling bus bar coupled to the connection bus bar, wherein the connection bus bar and the coupling bus bar have a bar shape extending in an upper and lower direction, and each of the connection bus bar and the coupling bus bar include a front surface, a rear surface and side surfaces, wherein the upper and lower direction is a direction in a length direction of the connection bus bar and the coupling bus bar, a direction in a width direction of the connection bus bar and the coupling bus bar is a left and right direction which is the stacking direction, and a direction in a depth direction of the connection bus bar and the coupling bus bar is a front and rear direction (F-direction), wherein the connection bus bar includes at least one insert groove formed so that a bent end portion of at least one of the electrode leads is inserted therein, the insert groove is formed at a front surface of the connection bus bar, the insert groove has a structure recessed from a front end to a rear end of the connection bus bar, and a recessed depth (D1-D4) of the insert groove (212, 212B1, 212B2, 212C, 212D) is equal to an entire thickness (T1-T4) of the at least one electrode lead inserted into the insert groove (212, 212B1, 212B2, 212C, 212D) in an inserting direction, and the rear surface of the coupling bus bar is formed to press the contacted electrode leads, wherein the bus bar assembly (200A-200D) further includes a bus bar frame having a front surface on which the connection bus bar is loaded, the bus bar frame being located between a front portion of a body of the secondary battery and a rear portion of the connection bus bar, wherein the bus bar frame is configured to have a perforation hole through which the electrode lead of the cell stack passes, or so that the electrode lead passes by the side portion of the bus bar frame and protrudes forwards, wherein the bus bar assembly (200A-200D) further includes a fastening member configured to couple the connection bus bar and the coupling bus bar to each other, and wherein the fastening member further includes a fastening bolt inserted through the connection bus bar and the coupling bus bar, and a cylindrical rod of the fastening bolt is inserted and fixed in the bus bar frame.