A battery module assembly having one or more plate-shaped cells, including two or more battery modules having cell units, each of which includes one or more battery cells, electrically connected to one another, a pair of an upper and lower case to surround outer circumferences of the modules such that one surface of each of the outermost modules is exposed outside in a state in which the modules are erected on their sides, one or more first fastening holes vertically formed at a top of the upper case and a bottom of the lower case in a direction in which first fastening holes face each other to fasten and fix the upper and lower case, and two or more second fastening holes horizontally formed at a front and/or a rear of the upper case and a front and/or a rear of the lower case to position or fix the assembly.