An electrolytic capacitor including: an element stack including a plurality of capacitor elements; a package body sealing the element stack; and a first and second external electrode. Each of the capacitor elements includes a first end at which the anode body is exposed, and a second end covered with the cathode section, with at least an end surface of the first end exposed from the package body. The capacitor elements include a first capacitor element in which the first end faces a first surface of the package body, and a second capacitor element in which the first end faces a second surface different from the first surface of the package body. The first and second capacitor elements stacked alternately. The first end of the first capacitor element and the first end of the second capacitor element are electrically connected to the first external electrode and the second external electrode, respectively.

An active metamaterial array of the present disclosure includes: a substrate; a plurality of metamaterial structures disposed on the substrate and spaced apart from each other; a conductivity variable material layer formed between each of the plurality of the metamaterial structures so as to selectively connect the metamaterial structures; an electrolyte material layer formed on the metamaterial structures and the conductivity variable material layer; and a gate electrode disposed at one end of the substrate so as to be in contact with one region of the electrolyte material layer, and when an external voltage is applied to the gate electrode, the gate electrode changes the conductivity of the conductivity variable material layer by controlling the migration of ions contained in the electrolyte material layer.

An active metamaterial array of the present disclosure includes: a substrate; a plurality of metamaterial structures disposed on the substrate and spaced apart from each other; a conductivity variable material layer formed between each of the plurality of the metamaterial structures so as to selectively connect the metamaterial structures; an electrolyte material layer formed on the metamaterial structures and the conductivity variable material layer; and a gate electrode disposed at one end of the substrate so as to be in contact with one region of the electrolyte material layer, and when an external voltage is applied to the gate electrode, the gate electrode changes the conductivity of the conductivity variable material layer by controlling the migration of ions contained in the electrolyte material layer.

A secondary battery is provided with first and second electrode assembly bodies and first and second negative electrode tab groups. The first and second negative electrode tab groups respectively have collected foil portions each constituted by a plurality of collected tab portions and extension portions. The extension portions of the respective tab groups have portions-to-be-welded and step portions. In the step portions, the plurality of tabs are laminated in a state that the end portions thereof are shifted in a step-like manner. The secondary battery is provided with an overlapped portion where the step portions of the first negative electrode tab group and the second negative electrode tab group are overlapped with each other in the lamination direction of the negative electrode tabs.

A secondary battery is provided with first and second electrode assembly bodies and first and second negative electrode tab groups. The first and second negative electrode tab groups respectively have collected foil portions each constituted by a plurality of collected tab portions and extension portions. The extension portions of the respective tab groups have portions-to-be-welded and step portions. In the step portions, the plurality of tabs are laminated in a state that the end portions thereof are shifted in a step-like manner. The secondary battery is provided with an overlapped portion where the step portions of the first negative electrode tab group and the second negative electrode tab group are overlapped with each other in the lamination direction of the negative electrode tabs.

A chip-style conductive polymer capacitor and a method for packaging the same, wherein the capacitor includes a chip-style conductive polymer capacitor element, a substrate, and a packaging material layer; the chip-style conductive polymer capacitor element is provided on the substrate and includes an anode tantalum core, an anode terminal, an anode base electrode, a dielectric layer, a cathode layer, and a cathode base electrode; the anode tantalum core and the cathode layer are separated by the dielectric layer; the anode terminal is made of a tantalum metal chip or a tantalum-niobium alloy chip, and has a rectangle or rounded rectangle cross section. The packaging method herein enables a vacuum injection molding packaging structure or a spray coating packaging structure covering a full range of a packaging thickness from 0.3 to 10 mm, realizes arrayed packaging with high efficiency, and ensures the electrical performance and reliability of the product.

A chip-style conductive polymer capacitor and a method for packaging the same, wherein the capacitor includes a chip-style conductive polymer capacitor element, a substrate, and a packaging material layer; the chip-style conductive polymer capacitor element is provided on the substrate and includes an anode tantalum core, an anode terminal, an anode base electrode, a dielectric layer, a cathode layer, and a cathode base electrode; the anode tantalum core and the cathode layer are separated by the dielectric layer; the anode terminal is made of a tantalum metal chip or a tantalum-niobium alloy chip, and has a rectangle or rounded rectangle cross section. The packaging method herein enables a vacuum injection molding packaging structure or a spray coating packaging structure covering a full range of a packaging thickness from 0.3 to 10 mm, realizes arrayed packaging with high efficiency, and ensures the electrical performance and reliability of the product.

An electrolytic capacitor includes a capacitor element. The capacitor element includes an anode body including a dielectric layer on a surface of the anode body, and a conductive polymer covering a part of the dielectric layer. The conductive polymer contains a first monomer unit corresponding to a 3,4-ethylenedioxythiophene compound and a second monomer unit corresponding to a 3,4-dialkoxythiophene compound.

An electrolytic capacitor includes a capacitor element. The capacitor element includes an anode body including a dielectric layer on a surface of the anode body, and a conductive polymer covering a part of the dielectric layer. The conductive polymer contains a first monomer unit corresponding to a 3,4-ethylenedioxythiophene compound and a second monomer unit corresponding to a 3,4-dialkoxythiophene compound.

A cathode and an electrolytic capacitor including the cathode which can suppress production of hydrogen gas are provided. The cathode of the electrolytic capacitor comprising cathode foil formed of valve action metal, and a conductive layer formed on a surface of the cathode foil. When current in a range of current density of leakage current of the electrolytic capacitor flows by electrochemical polarization, potential corresponding to said current is at a higher side than a natural immersion potential of reference cathode foil formed of the valve action metal with purity of 99.9%.