Abstract: A solid electrolytic capacitor that includes a cathode foil and solid electrolyte made of conductive polymer. This cathode foil is made by providing a nickel layer on a surface of a base material made of valve metal. This nickel layer includes a layer containing only nickel and a layer containing nickel oxide. Both large capacitance and low equivalent series resistance are achievable at the same time with this simple structure at low cost.

Abstract: An capacitor element is fabricated by winding an anode foil having a dielectric oxide film formed thereon, and a cathode foil subjected to a treatment of enlarging surface area in a manner that a separator is interposed therebetween. The capacitor element is immersed in a fluid dispersion containing conductive polymer fine particles dispersed therein. Thereafter, it is depressurized and dried so that the conductive polymer fine particles adhere to surfaces of fibers of the separator, fill between the fibers of the separator, and adhere to surfaces of the anode foil and the cathode foil in a manner that the adhesion and filling of the conductive polymer fine particles are such that an amount of the fine particles decreases from ends toward a center of the capacitor element. Then, it is impregnated with an electrolytic solution.

Abstract: A solid electrolytic capacitor has a capacitor element and a conductive polymer as a solid electrolyte. The capacitor element includes an anode foil having a dielectric oxide film thereon, a cathode foil, and a separator interposed between the anode and cathode foils, which are wound so as to form a capacitor element. The conductive polymer is disposed between the anode and cathode foils and formed by chemical polymerization of a polymerizable monomer. The separator is made of a nonwoven fabric of synthetic fiber and has an affinity to the polymerizable monomer. The separator includes main fibers and binder fibers each having a fiber diameter smaller than that of each of the main fibers and allowing the main fibers to be bonded together.

Abstract: An aluminum electrolytic capacitor having an excellent short-circuit resistance, high capacitance, long life, and low equivalent series resistance (ESR) is provided. For this purpose, the aluminum electrolytic capacitor includes a capacitor element having a positive electrode foil, a first separator, a negative electrode foil, and a second separator, which are sequentially laminated one on another and wound together. After the capacitor element is impregnated with a driving electrolyte solution and housed in a metallic case, an open end of the metallic case is sealed with a sealing material. A ratio of B/A, i.e. a ratio of total thickness B of the first and second separators after winding with respect to total thickness A of the first and second separators before winding, is set in the range from 0.5 to 0.8.

Abstract: An capacitor element is fabricated by winding an anode foil having a dielectric oxide film formed thereon, and a cathode foil subjected to a treatment of enlarging surface area in a manner that a separator is interposed therebetween. The capacitor element is immersed in a fluid dispersion containing conductive polymer fine particles dispersed therein. Thereafter, it is depressurized and dried so that the conductive polymer fine particles adhere to surfaces of fibers of the separator, fill between the fibers of the separator, and adhere to surfaces of the anode foil and the cathode foil in a manner that the adhesion and filling of the conductive polymer fine particles are such that an amount of the fine particles decreases from ends toward a center of the capacitor element. Then, it is impregnated with an electrolytic solution.

Abstract: A solid electrolytic capacitor that includes a cathode foil and solid electrolyte made of conductive polymer. This cathode foil is made by providing a nickel layer on a surface of a base material made of valve metal. This nickel layer includes a layer containing only nickel and a layer containing nickel oxide. Both large capacitance and low equivalent series resistance are achievable at the same time with this simple structure at low cost.

Abstract: It is provided the electrolytic solution for use in the electrolytic capacitor including a capacitor element and a casing containing said capacitor element, said capacitor element including a pair of electrodes, and a conductive separator (E) which is formed with a conductive polymer layer (F) containing a dopant agent (H) on its surface and is interposed between said pair of electrodes, said conductive separator (E) and said pair of electrodes being rolled up in an overlapped state with each other, and spaces between said pair of electrodes being impregnated with the electrolytic solution for electrolytic capacitor, wherein an acid component (D) and a base component (C) as electrolytic components to be contained in said electrolytic solution are at such a molar ratio that the acid component (D) is excessive. By use of said electrolytic solution for electrolytic capacitor, the increase in the ESR with the elapse of time in an electrolytic capacitor is suppressed.