BATTERY MODULE

A battery module includes a cell stack including a plurality of a battery cell, a module case at least partially accommodating the cell stack, and a cooling unit disposed at one side of the cell stack. The battery cell includes a cell case, an electrode assembly and an electrolyte accommodated in the cell case, and an electrolyte storage unit inserted into the cell case to supply a supplementary electrolyte. The electrolyte storage unit is disposed between the electrode assembly and the cooling unit in a cross-sectional view.