A battery module comprising: a sub-module comprising a cell stack assembly comprising a plurality of battery cells and a cooling fin located between adjacent battery cells, a front bus bar frame assembly coupled to a side of the cell stack assembly in a longitudinal direction of the cell stack assembly, and a rear bus bar frame assembly coupled to the other side of the cell stack assembly in the longitudinal direction of the cell stack assembly; a module housing in which the sub-module is accommodated; a front sealing plate covering an opening portion formed on a side of the module housing in a longitudinal direction of the module housing and comprising an insulating oil inlet; and a rear sealing plate covering an opening portion formed on the other side of the module housing in the longitudinal direction of the module housing and comprising an insulating oil outlet, characterized in that the cooling fin comprises: a body contact portion located between adjacent battery cells; and an edge cover portion bent at any one of an upper end and a lower end of the body contact portion to cover an edge of one of the battery cells, wherein the body contact portion directly contact bodies of the battery cells, wherein insulating oil passages are formed between the module housing and an edge of the battery cell and between the edge cover portion and the edge of the battery cell. a sub-module comprising a cell stack assembly comprising a plurality of battery cells and a cooling fin located between adjacent battery cells, a front bus bar frame assembly coupled to a side of the cell stack assembly in a longitudinal direction of the cell stack assembly, and a rear bus bar frame assembly coupled to the other side of the cell stack assembly in the longitudinal direction of the cell stack assembly; a module housing in which the sub-module is accommodated; a front sealing plate covering an opening portion formed on a side of the module housing in a longitudinal direction of the module housing and comprising an insulating oil inlet; and a rear sealing plate covering an opening portion formed on the other side of the module housing in the longitudinal direction of the module housing and comprising an insulating oil outlet, characterized in that the cooling fin comprises: a body contact portion located between adjacent battery cells; and an edge cover portion bent at any one of an upper end and a lower end of the body contact portion to cover an edge of one of the battery cells, wherein the body contact portion directly contact bodies of the battery cells, wherein insulating oil passages are formed between the module housing and an edge of the battery cell and between the edge cover portion and the edge of the battery cell. a body contact portion located between adjacent battery cells; and an edge cover portion bent at any one of an upper end and a lower end of the body contact portion to cover an edge of one of the battery cells, wherein the body contact portion directly contact bodies of the battery cells, wherein insulating oil passages are formed between the module housing and an edge of the battery cell and between the edge cover portion and the edge of the battery cell.