POWER STORAGE DEVICE AND METHOD OF MANUFACTURING SAME

A method of manufacturing a power storage device includes: producing an electrode assembly (200) having a first electrode tab group (220); and forming a joining portion at which first electrode tabs (230) in the first electrode tab group (220) are joined together by applying vibration to the first electrode tab group (220) by a horn (10) in a state in which the first electrode tab group (220) is sandwiched between the horn (10) and an anvil (20) in a stacking direction of the first electrode tabs (230), wherein a line-shaped protuberance (11) is provided in a surface of one of the horn (10) and the anvil (20), the surface being to be in abutment with a first outer surface of the first electrode tab group (220), and in the forming the joining portion, the vibration is applied in a state in which the line-shaped protuberance (11) is in abutment with the first outer surface of the first electrode tab group (220).