BATTERY MODULE

Discussed is a battery module that includes cell stacks in which a plurality of cells are stacked, respectively, and a partition wall disposed between the cell stacks adjacent to each other. The partition wall includes a first partition wall having a horizontal coupling space and an inner groove, and a second partition wall having a vertical coupling space and a protrusion. A portion of the second partition wall is fitted into the horizontal coupling space, and a portion of the first partition wall is fitted into the vertical coupling space, and the inner groove and the protrusion are coupled to engage with each other.