A battery module of the present disclosure may include, a cell assembly including at least one battery cell, a busbar assembly including a terminal busbar electrically connected to an electrode lead of the cell assembly, and a busbar frame covering the cell assembly on at least one side, and an insulating frame covering the busbar assembly from the outside, and further including a nut which is set to a floatable size in a nut insertion chamber adjacent to a terminal busbar and provided with a space inside the insulating frame, and is mounted in the nut insertion chamber.