A battery module assembly comprising: two or more battery modules, each of which comprises two or more plate-shaped battery cells (10, 20) vertically stacked such that electrode leads (11, 12) of the battery cells are arranged in one direction, each of the battery modules having terminal parts connected to an outside; a base plate comprising module receiving parts, on tops of which the battery modules are loaded in a state in which electrode terminals (130, 140) of the battery modules are arranged in one direction, the base plate being provided at an outer edge thereof with upwardly bent side walls; an upper cover plate comprising downwardly bent side walls formed at opposite sides thereof on the basis of the electrode terminals (130, 140) of the battery modules, the upper cover plate being fixed on the base plate to form a top of the battery module assembly; a plate-shaped assembly cover loaded on tops of the battery modules and coupled to the battery modules in a fastening fashion, the assembly cover fixing a cable; an electrically insulative module cover mounted on the electrode leads (11, 12) of the battery cells (10, 20) and fixed to the base plate and the assembly cover in a fastening fashion; characterized in that the module cover comprises: a bushing insertion hole, through which the module cover is fixed to the base plate; second hooks (211, 212) coupled to protruding parts (151, 152) of each of the battery modules; and a first hook including cable terminal fixing protrusions (232, 233) for fixing the ends of the cables; wherein the module cover is provided at the top thereof with upward protrusions (251, 252) which are fixedly engaged in fastening holes of the assembly cover. two or more battery modules, each of which comprises two or more plate-shaped battery cells (10, 20) vertically stacked such that electrode leads (11, 12) of the battery cells are arranged in one direction, each of the battery modules having terminal parts connected to an outside; a base plate comprising module receiving parts, on tops of which the battery modules are loaded in a state in which electrode terminals (130, 140) of the battery modules are arranged in one direction, the base plate being provided at an outer edge thereof with upwardly bent side walls; an upper cover plate comprising downwardly bent side walls formed at opposite sides thereof on the basis of the electrode terminals (130, 140) of the battery modules, the upper cover plate being fixed on the base plate to form a top of the battery module assembly; a plate-shaped assembly cover loaded on tops of the battery modules and coupled to the battery modules in a fastening fashion, the assembly cover fixing a cable; an electrically insulative module cover mounted on the electrode leads (11, 12) of the battery cells (10, 20) and fixed to the base plate and the assembly cover in a fastening fashion; a bushing insertion hole, through which the module cover is fixed to the base plate; second hooks (211, 212) coupled to protruding parts (151, 152) of each of the battery modules; and a first hook including cable terminal fixing protrusions (232, 233) for fixing the ends of the cables; wherein the module cover is provided at the top thereof with upward protrusions (251, 252) which are fixedly engaged in fastening holes of the assembly cover.