POWER STORAGE DEVICE AND METHOD OF MANUFACTURING SAME

A method of manufacturing a power storage device includes: producing an electrode assembly having a first electrode tab group; and forming a joining portion at which first electrode tabs in the first electrode tab group are joined together by applying vibration to the first electrode tab group by a horn in a state in which the first electrode tab group is sandwiched between the horn and an anvil in a stacking direction of the first electrode tabs, wherein a line-shaped protuberance is provided in a surface of one of the horn and the anvil, the surface being to be in abutment with a first outer surface of the first electrode tab group, and in the forming the joining portion, the vibration is applied in a state in which the line-shaped protuberance is in abutment with the first outer surface of the first electrode tab group.