A battery module comprising: a plurality of cell stacks, each cell stack comprising: a plurality of unit cells arranged in a first direction; and an insulating member around the plurality of unit cells; the battery module further comprising: a first module housing comprising a plurality of receiving parts each receiving a cell stack; and a coupling part, wherein each of the receiving parts comprises a fixing wall around the cell stack, at least a portion of the fixing wall contacting the cell stack, wherein the fixing wall comprises end walls at respective sides of each of the receiving parts in the first direction to engage end surfaces of respective sides of the cell stack in the first direction, and wherein the coupling part of the first module housing is configured to be coupled to a coupling part of a second module housing of an adjacent battery module, the second module housing being adjacent to the first module housing, wherein the first module housing further comprises a separation wall extending in the first direction and partitioning an inner space around an outer wall of the first module housing to form adjacent ones of the plurality of receiving parts, and wherein the separation wall corresponds to a part of the fixing wall of each of the receiving parts along a second direction perpendicular to a first direction, wherein the separation wall contacts a side surface of the cell stack received in the respective receiving part, wherein the end walls comprise a first end wall and a second end wall, and wherein the first end wall faces the outer wall of the first module housing and is spaced apart from the outer wall along the first direction, defining a first impact absorbing space between the first end wall and the outer wall. a plurality of cell stacks, each cell stack comprising: a plurality of unit cells arranged in a first direction; and an insulating member around the plurality of unit cells; a plurality of unit cells arranged in a first direction; and an insulating member around the plurality of unit cells; the battery module further comprising: a first module housing comprising a plurality of receiving parts each receiving a cell stack; and a coupling part, wherein each of the receiving parts comprises a fixing wall around the cell stack, at least a portion of the fixing wall contacting the cell stack, wherein the fixing wall comprises end walls at respective sides of each of the receiving parts in the first direction to engage end surfaces of respective sides of the cell stack in the first direction, and wherein the coupling part of the first module housing is configured to be coupled to a coupling part of a second module housing of an adjacent battery module, the second module housing being adjacent to the first module housing, wherein the first module housing further comprises a separation wall extending in the first direction and partitioning an inner space around an outer wall of the first module housing to form adjacent ones of the plurality of receiving parts, and wherein the separation wall corresponds to a part of the fixing wall of each of the receiving parts along a second direction perpendicular to a first direction, wherein the separation wall contacts a side surface of the cell stack received in the respective receiving part, wherein the end walls comprise a first end wall and a second end wall, and wherein the first end wall faces the outer wall of the first module housing and is spaced apart from the outer wall along the first direction, defining a first impact absorbing space between the first end wall and the outer wall. a first module housing comprising a plurality of receiving parts each receiving a cell stack; and a coupling part, wherein each of the receiving parts comprises a fixing wall around the cell stack, at least a portion of the fixing wall contacting the cell stack, wherein the fixing wall comprises end walls at respective sides of each of the receiving parts in the first direction to engage end surfaces of respective sides of the cell stack in the first direction, and wherein the coupling part of the first module housing is configured to be coupled to a coupling part of a second module housing of an adjacent battery module, the second module housing being adjacent to the first module housing, wherein the first module housing further comprises a separation wall extending in the first direction and partitioning an inner space around an outer wall of the first module housing to form adjacent ones of the plurality of receiving parts, and wherein the separation wall corresponds to a part of the fixing wall of each of the receiving parts along a second direction perpendicular to a first direction, wherein the separation wall contacts a side surface of the cell stack received in the respective receiving part, wherein the end walls comprise a first end wall and a second end wall, and wherein the first end wall faces the outer wall of the first module housing and is spaced apart from the outer wall along the first direction, defining a first impact absorbing space between the first end wall and the outer wall.