BATTERY PACK

The present invention provides a battery pack. More specifically, the battery pack of the present invention, which contains a cell stack assembly including a plurality of cells, is characterized by including: a pack case in which a cell stack assembly is mounted; and a supplementary partition wall coupled to the pack case to compartmentalize a space inside the pack case; wherein the pack case includes: a base plate supporting a lower part of the mounted cell stack assembly; and a side wall of hollow structure coupled to the base plate to support a side part of the cell stack assembly, and including a gas venting path internally; and wherein the supplementary partition wall is coupled to the base plate and side wall of the pack case, and includes a gas flow path internally in connection with the gas venting path of the side wall.