KR-20260066173-A - electrolytic capacitor

Abstract

In an electrolytic capacitor (1) having a main body case (2) having an opening, a capacitor element (10) housed within the main body case (2), and an opening sealing body (5) that seals the opening of the main body case (2), the capacitor element (10) has an anode foil (11) having an oxide film (16) on its surface and a cathode foil (12) facing the anode foil (11) with a separator (13) interposed therebetween, and an electrolyte layer (19) between the anode foil (11) and the cathode foil (12) having a solid electrolyte (17) containing a conductive polymer and a liquid electrolyte (18) covering at least a portion of the solid electrolyte (17), and the liquid electrolyte (18) contains at least an unsaturated fatty acid salt, and the unsaturated fatty acid salt alone or a mixture of unsaturated fatty acids added to the unsaturated fatty acid salt occupies 50% or more of the liquid electrolyte (18).

Inventors

• 가쿠마 겐지

Assignees

• 썬 일렉트로닉 인더스트리즈 코프.

Dates

Publication Date

20260512

Application Date

20231023

Claims (6)

1. An electrolytic capacitor comprising a main body case having an opening, a capacitor element housed within the main body case, and an opening sealing body that seals the opening of the main body case, The above capacitor element has an anode foil having an oxide film on its surface, and a cathode foil facing the anode foil wound with a separator interposed therebetween, and an electrolyte layer between the anode foil and the cathode foil comprising a solid electrolyte containing a conductive polymer and a liquid electrolyte covering at least a portion of the solid electrolyte. An electrolytic capacitor characterized in that the liquid electrolyte comprises at least an unsaturated fatty acid salt, and the unsaturated fatty acid salt alone or a mixture of the unsaturated fatty acid salt and an unsaturated fatty acid comprises at least 50% by weight of the liquid electrolyte.
2. In paragraph 1, An electrolytic capacitor characterized in that the above-mentioned unsaturated fatty acid salt is in a liquid state at 20°C or higher.
3. In paragraph 2, The above liquid electrolyte comprises the above mixture, and the electrolytic capacitor is characterized by using at least one of palmitoleic acid, oleic acid, linoleic acid, eicosadienoic acid, linolenic acid, pinolenic acid, ricinoleic acid, mic acid, dihomo-γ-linolenic acid, eicosatrienoic acid, stearidonic acid, arachidonic acid, eicosatetraenoic acid, docosatetraenoic acid, boseopentaenoic acid, eicosapentaenoic acid, ozbondic acid, sardine acid, tetracosapentaenoic acid, nisinic acid, docosahexaenoic acid, 12-vinyl-8-octadecene acid, and 7,12-dimethyl-7,11-octadecadiene-1,18-dicarboxylic acid as the unsaturated fatty acid.
4. In paragraph 2, An electrolytic capacitor characterized by using at least one of trimethylamine, N,N-dimethylbenzylamine, pyridine, N,N-dimethylaniline, aniline, 2-mercaptobenzimidazole, 1-naphthylamine, morpholine, 1,10-phenanthroline, 2,2'-bipyridyl, acetanilide, acetamide, or a derivative thereof as the base of the above-mentioned unsaturated fatty acid salt.
5. In any one of paragraphs 1 through 4, An electrolytic capacitor characterized by the above liquid electrolyte including a fat-soluble antioxidant.
6. In paragraph 5, An electrolytic capacitor characterized in that the above-mentioned fat-soluble antioxidant is included in an amount of 30% by weight or less of the above-mentioned liquid electrolyte.

Description

electrolytic capacitor The present invention relates to an electrolytic capacitor having a solid electrolyte and a liquid electrolyte. A conventional electrolytic capacitor is disclosed in Patent Document 1. This electrolytic capacitor has a capacitor element formed by winding an anode foil having an oxide film and a counter-negative foil with a separator interposed therebetween. The capacitor element is housed in an outer case, and the outer case is sealed by an opening seal. Lead terminals are connected to the anode foil and the negative foil, respectively, and the lead terminals are drawn out of the outer case by penetrating the opening seal. The capacitor element has a solid electrolyte layer made of a conductive polymer inside, and is impregnated with an electrolyte solution. In addition, the solute of the electrolyte contains 3 to 30 wt% of at least one selected from the group consisting of aliphatic hydroxy acids and their salts. By doing so, the equivalent series resistance (hereinafter ESR) of the electrolytic capacitor is lowered under high-temperature environments. Furthermore, the oxidation of the conductive polymer can be suppressed by the oxidative degradation prevention action of the aliphatic hydroxy acid itself. FIG. 1 is a cross-sectional view illustrating an electrolytic capacitor of an embodiment of the present invention. FIG. 2 is a perspective view illustrating a capacitor element of an electrolytic capacitor according to an embodiment of the present invention. FIG. 3 is a partially enlarged cross-sectional view illustrating a capacitor element of an electrolytic capacitor according to an embodiment of the present invention. FIG. 4 is a diagram showing the change in ESR over time of the embodiments and comparative examples of the present invention. FIG. 5 is a drawing showing an enlarged view of the range in which the ESR of FIG. 4 is 10 to 1000 mΩ. Embodiments of the present invention are described below with reference to the drawings. FIG. 1 is a cross-sectional view illustrating an electrolytic capacitor (1) of one embodiment. The electrolytic capacitor (1) comprises a main body case (2), a capacitor element (10), and an opening seal (5). The main body case (2) is formed in a cylindrical shape with a circular bottom cross section using a metal such as aluminum or resin, and one end in the axial direction is closed by a closed surface (2a) and the other end has an opening (2b). In terms of processability and sealing performance, it is preferable to form the main body case (2) with aluminum. The opening seal (5) is formed into a disc shape by a molded product of an elastic body that is an insulator, such as butyl rubber or ethylene propylene rubber, and has a pair of through holes (5a). Lead terminals (7, 8) of a capacitor element (10) are inserted and penetrated through the pair of through holes (5a) by press-fitting. As a result, the lead terminals (7, 8) are drawn out of the opening seal and connected to a circuit board (not shown) by soldering or the like. A capacitor element (10) is housed within the main body case (2), and an opening seal (5) is placed in the opening (2b). With the opening seal (5) placed in the opening (2b) of the main body case (2), a tightening process is performed on the main body case (2) to press the outer surface. As a result, a tightening process part (2c) protruding toward the inner side is formed on the main body case (2). By the tightening process part (2c), the outer surface of the opening seal (5) is compressed in the inner direction and adheres to the inner surface of the main body case (2). Additionally, due to the compression of the opening seal (5), the inner surface of the through hole (5a) adheres to the lead terminals (7, 8). As a result, the opening (2b) of the main body case (2) is sealed by the opening seal (5). The end of the opening (2b) side of the main body case (2) is bent toward the opening seal (5) to form a bent portion (2d). The bent portion (2d) and the tightening portion (2c) prevent the opening seal (5) from coming out of the main body case (2). In addition, to increase the mounting capability on the circuit board, a known mounting plate may be provided. The lead terminals (7, 8) are bent in the diameter direction through the mounting plate, and this bent portion can be used as a soldering portion on the circuit board. FIG. 2 illustrates a perspective view of a capacitor element (10). The capacitor element (10) has a positive electrode foil (11), a negative electrode foil (12), and a separator (13) formed in a long strip shape. A capacitor element (10) is formed by winding a pair of electrode foils, consisting of opposing positive electrode foils (11) and negative electrode foils (12), into a roughly cylindrical shape with the separator (13) interposed. The ends of the positive electrode foil (11) or the separator (13) are fixed by an adhesive tape (14). The width of the separator (13) in the short direction (axial direction) i