To provide a power storage device not generating unevenness (irregularity) on a jointing structure of a current collector foil between a plurality of slits for inserting current collector foil arranged on one current collector terminal.

On the winding-type or lamination-type power storage device, appropriate number of current collector foil end parts 15 are inserted into a plurality of slits 28a, 28b arranged at least on the current collector terminal 20 of either a cathode or an anode, and the current collector foil end parts 15 and a slit inner wall face adjacent to the end part are jointed by welding. Here, the welded part 15b is formed on an area ranging from nearly central part of the current collector foil end part inserted into the slit part to the neighboring area of an opening of the slit, and respective welded parts of at least two slits adjacent to each other are formed so as to be linearly arrayed in lateral direction almost rectangularly crossing the insertion direction of the current collector foil end part, in lateral cross section of the current collector terminal almost rectangularly crossing the longitudinal direction of the opening of the slit.

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