A battery module assembly comprising: two or more battery modules (101, 102, 103, 104), 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 (10, 20) are arranged in one direction; a base plate comprising module receiving parts (301, 302, 303, 304), on tops of which the battery modules (101, 102, 103, 104) are loaded in a state in which electrode terminals of the battery modules (101, 102, 103, 104) 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 of the battery modules (101, 102, 103, 104), the upper cover plate being fixed on the base plate to form a top of the battery module assembly; and a plate-shaped assembly cover loaded on tops of the battery modules (101, 102, 103, 104) and coupled to the battery modules (101, 102, 103, 104) in a fastening fashion, the assembly cover comprising a cable fixing part for fixing a cable, characterized in that each of the battery modules (101, 102, 103, 104) further comprises 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, each module cover comprising: a bushing insertion hole, through which the module cover is mounted and fixed to the base plate, a first hook for fixing cables connected to the electrode terminals (130, 140) of each of the battery modules (101, 102, 103, 104); an upward protrusion (251, 252) for positioning fixedly engaged with the assembly cover; and a second hook (211, 212) mounted and fixed to each of the battery modules (101, 102, 103, 104), the assembly cover is provided with openings, through which the tops of the battery modules (101, 102, 103, 104) are exposed, the openings being formed by drilling, and the battery modules (101, 102, 103, 104) are provided with fastening holes for fastening with the assembly cover. two or more battery modules (101, 102, 103, 104), 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 (10, 20) are arranged in one direction; a base plate comprising module receiving parts (301, 302, 303, 304), on tops of which the battery modules (101, 102, 103, 104) are loaded in a state in which electrode terminals of the battery modules (101, 102, 103, 104) 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 of the battery modules (101, 102, 103, 104), the upper cover plate being fixed on the base plate to form a top of the battery module assembly; and a plate-shaped assembly cover loaded on tops of the battery modules (101, 102, 103, 104) and coupled to the battery modules (101, 102, 103, 104) in a fastening fashion, the assembly cover comprising a cable fixing part for fixing a cable, characterized in that each of the battery modules (101, 102, 103, 104) further comprises 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, each module cover comprising: a bushing insertion hole, through which the module cover is mounted and fixed to the base plate, a first hook for fixing cables connected to the electrode terminals (130, 140) of each of the battery modules (101, 102, 103, 104); an upward protrusion (251, 252) for positioning fixedly engaged with the assembly cover; and a second hook (211, 212) mounted and fixed to each of the battery modules (101, 102, 103, 104), a bushing insertion hole, through which the module cover is mounted and fixed to the base plate, a first hook for fixing cables connected to the electrode terminals (130, 140) of each of the battery modules (101, 102, 103, 104); an upward protrusion (251, 252) for positioning fixedly engaged with the assembly cover; and a second hook (211, 212) mounted and fixed to each of the battery modules (101, 102, 103, 104), the assembly cover is provided with openings, through which the tops of the battery modules (101, 102, 103, 104) are exposed, the openings being formed by drilling, and the battery modules (101, 102, 103, 104) are provided with fastening holes for fastening with the assembly cover.