Disclosed is a battery pack including a battery module array constituted by one or more battery modules each including one or more unit modules each configured to have a structure in which a battery cell is surrounded by a cell cover are mounted in a module case in a state in which the unit modules are stacked while being vertically upright, a base plate on which the battery module array is loaded, a pair of end plates to support opposite sides of the array in a state in which a lower end of each of the end plates is fixed to the base plate, and an insulation member disposed between the array and each of the end plates, the insulation member being provided at a surface thereof facing the array with one or more ribs to absorb shock caused by external force and to define a coolant flow channel.