NOVELTY - The power storage device comprises a positive electrode (117) having a positive-electrode current collector (111) with first projections, a first insulator provided on the first projections and a positive-electrode active material (112) provided on the first insulator and the positive-electrode current collector, and a negative electrode (127) having a negative-electrode current collector (121) with second projections, a second insulator provided on the second projections and a negative-electrode active material provided on the second insulator and the negative-electrode current collector.    USE - Used as a power storage device such as lithium-ion secondary batteries.    ADVANTAGE - The power storage device has high capacity and reliability and increased surface area, and absorbs or disperses the pressure in the electrodes thus preventing the breaking of the separator.    DETAILED DESCRIPTION - The power storage device comprises a positive electrode (117) having a positive-electrode current collector (111) with first projections, a first insulator provided on the first projections and a positive-electrode active material (112) provided on the first insulator and the positive-electrode current collector, a negative electrode (127) having a negative-electrode current collector (121) with second projections, a second insulator provided on the second projections and a negative-electrode active material provided on the second insulator and the negative-electrode current collector, a separator (131) provided between the positive electrode and the negative electrode, and an electrolyte (132) provided between the positive electrode and the negative electrode and containing carrier ions. A width of the first insulator is larger than a width of each of the first projections. Each of the first projections and each of the second projections have a ratio of height to width of 10-1000.    DESCRIPTION OF DRAWING(S) - The diagram shows a cross-sectional view of a manufacturing process of a power storage device.    Positive-electrode current collector (111)    Positive-electrode active material (112)    Positive electrode (117)    Negative-electrode current collector (121)    Negative electrode (127)    Separator (131)    Electrolyte. (132)