A battery pack comprises a plurality of pouch battery cells stacked along a first direction; a main board located in the first direction relative to the plurality of pouch battery cells and including a power port for electrical connection to an external device; a sub board located in a second direction perpendicular to the first direction relative to the plurality of pouch battery cells and connected to positive electrode tabs and negative electrode tabs of the plurality of pouch battery cells; and a connection member electrically connecting the sub board to the main board.