A power storage device that includes a first adhesive member between a first current collector and a second surface layer, and a second adhesive member between a second current collector and a first surface layer. A first electrolyte retaining layer is provided between the first adhesive member and the first current collector. A second electrolyte retaining layer is provided between the second adhesive member and the second current collector.

A power storage device that includes a first adhesive member between a first current collector and a second surface layer, and a second adhesive member between a second current collector and a first surface layer. A first electrolyte retaining layer is provided between the first adhesive member and the first current collector. A second electrolyte retaining layer is provided between the second adhesive member and the second current collector.

Provided are a current collector which has an excellent high-rate property and exerts a sufficient safety function when employed in a secondary battery or a capacitor, as well as an electrode, a secondary battery or a capacitor in which said current collector is employed. According to the invention, a current collector is provided which comprises: metal foil; and a conductive layer with a film thickness of 0.1 μm to 10 μm formed on a surface of said metal foil. Here, said conductive layer includes a conductive material and a binder material. A melting point of said binder material is 80° C. to 150° C. Further, said binder material shows, in differential scanning calorimetry (DSC) in a range from room temperature to 200° C., one or more endothermic peaks in the heating-up process. In a case where said binder material shows two or more endothermic peaks, each difference between said peaks is 15° C. or more. Moreover, said binder material shows one or more exothermic peaks in the cooling-down process. In a case where said binder material shows only one exothermic peak, said exothermic peak falls within a range of 50 to 120° C., and a width at half maximum of said exothermic peak is 10° C. or less. On the other hand, in a case where said binder material shows two or more exothermic peaks, a maximum exothermic peak among said exothermic peaks falls within a range of 50 to 120° C., and a width at half maximum of said exothermic peak is 10° C. or less.

Provided are a current collector which has an excellent high-rate property and exerts a sufficient safety function when employed in a secondary battery or a capacitor, as well as an electrode, a secondary battery or a capacitor in which said current collector is employed. According to the invention, a current collector is provided which comprises: metal foil; and a conductive layer with a film thickness of 0.1 μm to 10 μm formed on a surface of said metal foil. Here, said conductive layer includes a conductive material and a binder material. A melting point of said binder material is 80° C. to 150° C. Further, said binder material shows, in differential scanning calorimetry (DSC) in a range from room temperature to 200° C., one or more endothermic peaks in the heating-up process. In a case where said binder material shows two or more endothermic peaks, each difference between said peaks is 15° C. or more. Moreover, said binder material shows one or more exothermic peaks in the cooling-down process. In a case where said binder material shows only one exothermic peak, said exothermic peak falls within a range of 50 to 120° C., and a width at half maximum of said exothermic peak is 10° C. or less. On the other hand, in a case where said binder material shows two or more exothermic peaks, a maximum exothermic peak among said exothermic peaks falls within a range of 50 to 120° C., and a width at half maximum of said exothermic peak is 10° C. or less.

Provided is an aluminum member for electrodes capable of stably maintaining a low electric resistance state, and a method of producing an aluminum member for electrodes. An aluminum member for electrodes includes an aluminum substrate and an oxide film that is laminated on at least one main surface of the aluminum substrate, and the oxide film has a density of 2.7 to 4.1 g/cm.sup.3 and a thickness of 5 nm or less.

Provided is an aluminum member for electrodes capable of stably maintaining a low electric resistance state, and a method of producing an aluminum member for electrodes. An aluminum member for electrodes includes an aluminum substrate and an oxide film that is laminated on at least one main surface of the aluminum substrate, and the oxide film has a density of 2.7 to 4.1 g/cm.sup.3 and a thickness of 5 nm or less.

A power storage device with a high capacity is provided. A power storage device with a high energy density is provided. A highly reliable power storage device is provided. A power storage device with a long lifetime is provided.

A method for manufacturing an electrode is characterized by including the steps of: mixing an active material, a binder, and a conductive additive to form a slurry; applying the slurry onto a current collector; drying the applied slurry to form an active material layer; and performing heat treatment in an atmosphere containing oxygen to form a film in contact with the current collector. The film is formed on a surface of the current collector where the active material layer is not provided and includes at least one component of the current collector and oxygen.

A power storage device with a high capacity is provided. A power storage device with a high energy density is provided. A highly reliable power storage device is provided. A power storage device with a long lifetime is provided.

A method for manufacturing an electrode is characterized by including the steps of: mixing an active material, a binder, and a conductive additive to form a slurry; applying the slurry onto a current collector; drying the applied slurry to form an active material layer; and performing heat treatment in an atmosphere containing oxygen to form a film in contact with the current collector. The film is formed on a surface of the current collector where the active material layer is not provided and includes at least one component of the current collector and oxygen.

An electrochemical device is constituted by a positive electrode, a negative electrode, and separators that are wound in such a way that the first principal face of the negative electrode and third principal face of the positive electrode are on the inner side of winding, while the second principal face of the negative electrode and fourth principal face of the positive electrode are on the outer side of winding, with the separators separating the positive electrode and negative electrode; wherein the second principal face has a first region opposed to the positive electrode via the separator and a second region on the outermost side of winding and not opposed to the positive electrode, the second region includes a first uncoated region where no negative electrode active material layer is formed, and a metal lithium is joined to the first uncoated region and immersed in electrolytic solution.

An electrochemical device is constituted by a positive electrode, a negative electrode, and separators that are wound in such a way that the first principal face of the negative electrode and third principal face of the positive electrode are on the inner side of winding, while the second principal face of the negative electrode and fourth principal face of the positive electrode are on the outer side of winding, with the separators separating the positive electrode and negative electrode; wherein the second principal face has a first region opposed to the positive electrode via the separator and a second region on the outermost side of winding and not opposed to the positive electrode, the second region includes a first uncoated region where no negative electrode active material layer is formed, and a metal lithium is joined to the first uncoated region and immersed in electrolytic solution.