Electrolytic capacitor and method for manufacturing the same

Abstract

The present invention provides an electrolytic capacitor having an external electrode with good adhesion to a resin molded body and a method for manufacturing the same. The electrolytic capacitor comprises: a rectangular resin molded body, a laminated body including a capacitor element and a sealing resin for sealing the periphery of the laminated body, the capacitor element including an anode having a dielectric layer on the surface and a cathode opposite to the anode; a first external electrode formed on a first end face of the resin molded body and electrically connected to the anode exposed from the first end face; and a second external electrode formed on a second end face of the resin molded body and electrically connected to the cathode exposed from the second end face, the electrolytic capacitor being characterized in that the first external electrode and the second external electrode have a resin electrode layer including a conductive component and a resin component.

Description

[0001] This application is a divisional application of the application with application number "201911299373.2", application date December 16, 2019, and invention name "Electrolytic Capacitor". Technical Field

[0002] The present invention relates to electrolytic capacitors. Background Art

[0003] Patent Document 1 discloses a multilayer ceramic capacitor.

[0004] The stacked ceramic capacitor is manufactured by the following method, namely, after the first and second surfaces of the capacitor body are respectively impregnated with electrode paste and dried, a sintering treatment is performed to form a base film for external electrodes, and after the electrode paste is printed on the two ends in the length direction of the fifth surface of the capacitor body and dried, a sintering treatment is performed to form another base film for external electrodes to be continuous with the base film.

[0005] In addition, a method for forming external electrodes on a ceramic capacitor is described in Patent Document 2. Specifically, there is a first paste layer forming step of screen printing on the end face of the green body, and a second paste layer forming step of screen printing on the main surface of the green body, a first sintering step is performed after the first paste layer forming step, and a second sintering step is performed after the second paste layer forming step.

[0006] Prior Art Literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2017-152620

[0009] Patent Document 2: Japanese Patent Application Publication No. 2012-4480

[0010] The techniques described in Patent Documents 1 and 2 are both technologies that perform a sintering treatment at a high temperature of 600 to 800° C. after screen printing an electrode paste on a ceramic body. The composition, rheology, printing conditions, etc. of the electrode paste are suitable for the sintering treatment.

[0011] On the other hand, in an electrolytic capacitor such as a solid electrolytic capacitor, a laminate including a capacitor element including an anode having a dielectric layer on its surface and a cathode facing the anode is sealed around the laminate with a resin molded body and external electrodes are formed on the resin molded body.

[0012] When the external electrodes are formed on a resin molded body, the electrode layer cannot be formed by a high temperature sintering process, etc., so it is difficult to improve the adhesion between the resin molded body and the electrode layer. Therefore, the external electrode forming methods disclosed in Patent Documents 1 and 2 cannot be used directly.

[0013] In addition, when heat treatment is performed at a temperature of 150 to 260°C during the drying process during manufacturing or the reflow process during soldering and mounting, thermal stress is generated due to the difference in linear expansion coefficients between the resin molded body and the electrode layer, so there is a problem that the electrode layer is easily peeled off from the resin molded body. Summary of the invention

[0014] Problems to be solved by the invention

[0015] Therefore, an object of the present invention is to provide an electrolytic capacitor including external electrodes having good adhesion to a resin molded body.

[0016] Means for solving problems

[0017] The electrolytic capacitor of the present invention comprises: a rectangular parallelepiped resin molded body, a laminated body including a capacitor element, and a sealing resin for sealing the periphery of the laminated body, wherein the capacitor element comprises an anode having a dielectric layer on the surface and a cathode opposite to the anode; a first external electrode formed on a first end face of the resin molded body and electrically connected to the anode exposed from the first end face; and a second external electrode formed on a second end face of the resin molded body and electrically connected to the cathode exposed from the second end face, wherein the electrolytic capacitor is characterized in that the first external electrode and the second external electrode have a resin electrode layer containing a conductive component and a resin component.

[0018] Effects of the Invention

[0019] According to the present invention, it is possible to provide an electrolytic capacitor including external electrodes having good adhesion to a resin molded body. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a perspective view schematically showing an example of the electrolytic capacitor according to the first embodiment.

[0021] Figure 2 yes Figure 1 AA line cross-sectional view of the electrolytic capacitor shown.

[0022] Figure 3 It is a perspective view showing the first end surface side of the resin molded body being exposed.

[0023] Figure 4 It is a perspective view showing the second end surface side of the resin molded body exposed.

[0024] Figure 5 It is a side view schematically showing the dimensional relationship at the LT surface of the electrolytic capacitor.

[0025] Figure 6 It is a top view schematically showing the dimensional relationship at the LW plane of the electrolytic capacitor.

[0026] Figure 7 It is a bottom view schematically showing the dimensional relationship at the LW plane of the electrolytic capacitor.

[0027] Figure 8 It is a side view (end view) schematically showing the dimensional relationship at the WT plane of the electrolytic capacitor.

[0028] Fig. 9 It is a cross-sectional view schematically showing an example of an electrolytic capacitor according to a second embodiment.

[0029] Explanation of symbols

[0030] 1, 2 electrolytic capacitors;

[0031] 3 Anode;

[0032] 3a Valve action metal foil;

[0033] 3A, 3B, 3C, 3D anode part;

[0034] 5 Dielectric layer;

[0035] 7 cathode;

[0036] 7a Solid electrolyte layer;

[0037] 7b conductive layer;

[0038] 7c cathode lead layer;

[0039] 7A, 7B, 7C, 7D cathode part;

[0040] 8 Sealing resin;

[0041] 9. Resin molded body;

[0042] 9a 1st end surface;

[0043] 9a1, 9b1 upper surface corners;

[0044] 9a2, 9b2 bottom corners;

[0045] 9b 2nd end surface;

[0046] 9c: bottom surface of the resin molded body;

[0047] 9d upper surface of the resin molded body;

[0048] 9e 1st side;

[0049] 9f 2nd side;

[0050] 9g support base plate;

[0051] 11 1st external electrode;

[0052] 11a, 13a inner plating layer;

[0053] 11a1, 13a1 Ni plating layer;

[0054] 11a2, 13a2 Ag plating layer;

[0055] 11b, 13b resin electrode layer;

[0056] 11b1, 13b1 Ag printed resin electrode layer;

[0057] 11b2: first upper surface lead-in portion;

[0058] 11b3: first bottom surface lead-around portion;

[0059] 11c, 13c outer plating layer;

[0060] 11c1, 13c1 Ni plating layer;

[0061] 11c2, 13c2 Sn plating layer;

[0062] 13 2nd external electrode;

[0063] 13b2: second upper surface lead-in portion;

[0064] 13b3: second bottom surface lead-around portion;

[0065] 15 3rd external electrode;

[0066] 15a, 17a Cu pattern electrode layer;

[0067] 15b, 17b Au plating layer;

[0068] 17 4th external electrode;

[0069] 20 capacitor elements;

[0070] 30 laminates. DETAILED DESCRIPTION

[0071] Hereinafter, the electrolytic capacitor of the present invention will be described.

[0072] However, the present invention is not limited to the following configurations, and can be applied with appropriate changes within the scope of the present invention. In addition, an invention combining two or more preferred configurations of the embodiments of the present invention described below is also the present invention.

[0073] First, an electrolytic capacitor according to a first embodiment of the present invention will be described.

[0074] Figure 1 It is a perspective view schematically showing an example of the electrolytic capacitor according to the first embodiment.

[0075] exist Figure 1 2 shows a rectangular parallelepiped resin molded body 9 constituting the electrolytic capacitor 1 .

[0076] The resin molded body 9 has a length direction (L direction), a width direction (W direction), and a thickness direction (T direction), and has a first end face 9a and a second end face 9b that are opposite to each other in the length direction. A first external electrode 11 is formed on the first end face 9a, and a second external electrode 13 is formed on the second end face 9b.

[0077] The resin molded body 9 includes a bottom surface 9c and an upper surface 9d which are opposed to each other in the thickness direction. The bottom surface 9c is a surface on the side that becomes the mounting surface of the electrolytic capacitor 1.

[0078] A third external electrode 15 and a fourth external electrode 17 are formed on the bottom surface 9 c .

[0079] The third external electrode 15 is electrically connected to the first external electrode 11 , and the fourth external electrode 17 is electrically connected to the second external electrode 13 .

[0080] Furthermore, the resin molded body 9 includes a first side surface 9e and a second side surface 9f that are opposed to each other in the width direction.

[0081] In addition, in this specification, the surface along the length direction (L direction) and thickness direction (T direction) of the electrolytic capacitor or resin molded body is referred to as the LT surface, the surface along the length direction (L direction) and width direction (W direction) is referred to as the LW surface, and the surface along the thickness direction (T direction) and width direction (W direction) is referred to as the WT surface.

[0082] Figure 2 yes Figure 1 AA line cross-sectional view of the electrolytic capacitor shown.

[0083] Capacitor element 20 includes anode 3 having dielectric layer 5 on its surface, and cathode 7 facing anode 3 .

[0084] A plurality of capacitor elements 20 are stacked to form a stacked body 30, and the periphery of the stacked body 30 is sealed with a sealing resin 8 to form a resin molded body 9. In the stacked body 30, the stacked capacitor elements 20 may be bonded to each other via a conductive adhesive (not shown).

[0085] A first external electrode 11 is formed on the first end surface 9 a of the resin molded body 9 , and the first external electrode 11 is electrically connected to the anode 3 exposed from the first end surface 9 a .

[0086] A second external electrode 13 is formed on the second end surface 9 b of the resin molded body 9 , and the second external electrode 13 is electrically connected to the cathode 7 exposed from the second end surface 9 b .

[0087] Anode 3 constituting capacitor element 20 has valve metal foil 3a at the center and a porous layer (not shown) such as an etching layer on the surface. Dielectric layer 5 is provided on the surface of the porous layer.

[0088] Examples of the valve-action metal include single metals such as aluminum, tantalum, niobium, titanium, zirconium, magnesium, and silicon, or alloys containing these metals, etc. Among them, aluminum or an aluminum alloy is preferred.

[0089] The shape of the valve metal is not particularly limited, but is preferably a flat plate, and more preferably a foil. In addition, the porous layer is preferably an etched layer that has been etched with hydrochloric acid or the like.

[0090] The thickness of the valve metal foil before etching is preferably 60 μm or more and preferably 180 μm or less. In addition, the thickness of the valve metal foil (core) that is not etched after the etching process is preferably 10 μm or more and preferably 70 μm or less. The thickness of the porous layer is designed in accordance with the withstand voltage and electrostatic capacitance required by the electrolytic capacitor, but the porous layers on both sides of the valve metal foil are preferably 10 μm or more and preferably 120 μm or less.

[0091] The anode 3 is led out to the first end surface 9 a of the resin molded body 9 and is electrically connected to the first external electrode 11 .

[0092] The dielectric layer is preferably composed of an oxide film of the valve metal. For example, when aluminum foil is used as the valve metal substrate, an oxide film that becomes the dielectric layer can be formed by anodizing in an aqueous solution containing boric acid, phosphoric acid, adipic acid, or their sodium salts, ammonium salts, etc.

[0093] The dielectric layer is formed along the surface of the porous layer to form pores (recesses). The thickness of the dielectric layer is designed in accordance with the withstand voltage and electrostatic capacitance required of the electrolytic capacitor, but is preferably 10 nm or more and 100 nm or less.

[0094] Cathode 7 constituting capacitor element 20 is formed by laminating solid electrolyte layer 7a formed on dielectric layer 5, conductive layer 7b formed on solid electrolyte layer 7a, and cathode lead layer 7c formed on conductive layer 7b.

[0095] The electrolytic capacitor of the present embodiment, in which a solid electrolyte layer is provided as a part of a cathode, can be said to be a solid electrolytic capacitor.

[0096] As materials constituting the solid electrolyte layer, for example, conductive polymers having a skeleton of pyrrole, thiophene, aniline, etc. can be cited. As conductive polymers having a skeleton of thiophene, for example, PEDOT [poly (3, 4-ethylenedioxythiophene)] can be cited, and PEDOT:PSS in a composite with polystyrene sulfonic acid (PSS) as a dopant can also be cited.

[0097] The solid electrolyte layer is formed, for example, by a method of forming a polymer film of poly(3,4-ethylenedioxythiophene) or the like on the surface of the dielectric layer using a treatment solution containing a monomer such as 3,4-ethylenedioxythiophene, or by a method of applying a dispersion of a polymer such as poly(3,4-ethylenedioxythiophene) or the like to the surface of the dielectric layer and drying it. In addition, it is preferred that, after forming a solid electrolyte layer for an inner layer that fills the pores (recesses), a solid electrolyte layer for an outer layer that covers the entire dielectric layer is formed.

[0098] The solid electrolyte layer can be formed in a given area by applying the above-mentioned treatment liquid or dispersion liquid to the dielectric layer by sponge transfer, screen printing, spraying, dispenser, inkjet printing, etc. The thickness of the solid electrolyte layer is preferably 2 μm or more and preferably 20 μm or less.

[0099] The conductive layer is provided to electrically and mechanically connect the solid electrolyte layer and the cathode lead layer. For example, it is preferably a carbon layer, a graphene layer or a silver layer formed by applying a conductive paste such as a carbon paste, a graphene paste or a silver paste. In addition, it can also be a composite layer in which a silver layer is provided on a carbon layer or a graphene layer, or a mixed layer in which a carbon paste, a graphene paste and a silver paste are mixed.

[0100] The conductive layer can be formed by forming a conductive paste such as carbon paste on the solid electrolyte layer by sponge transfer, screen printing, spraying, dispenser, inkjet printing, etc. In addition, it is preferred that the cathode lead layer of the next step is laminated while the conductive layer is in a sticky state before drying. The thickness of the conductive layer is preferably 2 μm or more and preferably 20 μm or less.

[0101] The cathode lead layer can be formed by a metal foil or a printed electrode layer.

[0102] In the case of the metal foil, it is preferably composed of at least one metal selected from the group consisting of Al, Cu, Ag, and alloys containing these metals as main components. If the metal foil is composed of the above metals, the resistance value of the metal foil can be reduced, and the ESR can be reduced.

[0103] In addition, as the metal foil, a metal foil coated with carbon or titanium by a film forming method such as sputtering or evaporation can also be used. More preferably, an Al foil coated with carbon is used. The thickness of the metal foil is not particularly limited, but from the viewpoints of operability in the manufacturing process, miniaturization, and reduction of ESR, it is preferably 20 μm or more and preferably 50 μm or less.

[0104] In the case of printing the electrode layer, the electrode paste can be formed on the conductive layer by sponge transfer, screen printing, spraying, dispenser, inkjet printing, etc., thereby forming a cathode lead layer in a given area. As the electrode paste, an electrode paste with Ag, Cu, or Ni as a main component is preferred. In the case of using the cathode lead layer as a printed electrode layer, the thickness of the printed electrode layer can be made thinner than when a metal foil is used, and in the case of screen printing, the thickness can be set to be greater than 2 μm and less than 20 μm.

[0105] The cathode lead layer 7 c is led out to the second end surface 9 b of the resin molded body 9 and is electrically connected to the second external electrode 13 .

[0106] The sealing resin 8 constituting the resin molded body 9 contains at least a resin, preferably a resin and a filler. As the resin, for example, epoxy resin, phenolic resin, polyimide resin, silicone resin, polyamide resin, liquid crystal polymer, etc. are preferably used. Regarding the form of the sealing resin 8, both solid resin and liquid resin can be used. In addition, as a filler, for example, silica particles, alumina particles, metal particles, etc. are preferably used. It is more preferable to use a material containing silica particles in solid epoxy resin and phenolic resin.

[0107] As a molding method of the resin molded body, when a solid sealing material is used, it is preferred to use resin molding such as compression molding and transfer molding, and compression molding is more preferred. In addition, when a liquid sealing material is used, it is preferred to use molding methods such as a dispensing method and a printing method. Preferably, by compression molding, the laminate 30 of the capacitor element 20 consisting of the anode 3, the dielectric layer 5 and the cathode 7 is sealed with a sealing resin 8 as a resin molded body 9.

[0108] The resin molded body 9 has a rectangular parallelepiped shape, and has an upper surface 9d and a bottom surface 9c as LW surfaces, a first side surface 9e and a second side surface 9f as LT surfaces, and a first end surface 9a and a second end surface 9b as WT surfaces.

[0109] A support substrate 9 g is provided at the bottom of the resin molded body 9 , and the bottom surface of the support substrate 9 g serves as a bottom surface 9 c of the resin molded body 9 .

[0110] The support substrate is provided to integrate a stacked body in which a plurality of capacitor elements are stacked, and is preferably made of a glass epoxy substrate.

[0111] In addition, it is preferable that Cu pattern electrode layers 15 a and 17 a to be used as a third external electrode 15 and a fourth external electrode 17 described later are formed on the bottom surface side.

[0112] The resin molded body 9 is subjected to roller grinding after resin molding, and R (radius of curvature) is formed at the upper surface corners 9a1, 9b1 and the bottom surface corners 9a2, 9b2 to form chamfers. In the case of the resin molded body, it is softer than the ceramic body, and it is difficult to form R at the corners by roller grinding, but R can be formed smaller by adjusting the composition, particle size, shape, roller processing time, etc. of the medium. In addition, due to the difference in hardness between the sealing resin 8 and the supporting substrate 9g (sealing resin < supporting substrate), the R (radius of curvature) of the upper surface corners 9a1, 9b1 becomes larger than the R (radius of curvature) of the bottom surface corners 9a2, 962.

[0113] Furthermore, it is possible to improve the bonding properties between the first and second external electrodes formed on the end surfaces of the resin molded body and the third and fourth external electrodes formed on the bottom surface of the resin molded body.

[0114] In the resin molded body constituting the electrolytic capacitor, with respect to the anode exposed from the first end surface of the resin molded body and / or the cathode exposed from the second end surface of the resin molded body, it is preferred that the anode and / or cathode of one capacitor element is exposed by being divided into a plurality of anode parts and / or cathode parts. In this way, the adhesion between the resin molded body and the resin electrode layer is improved compared to a structure in which the anode and / or cathode of one capacitor element is exposed continuously in a straight line.

[0115] Figure 3 This is a perspective view showing the first end surface side of the resin molded body exposed. Figure 4 It is a perspective view showing the second end surface side of the resin molded body exposed.

[0116] exist Figure 3The anode 3 is exposed on the first end surface 9a of the resin molded body 9. The anode of one capacitor element is divided into four parts and exposed, and the exposed anodes are shown as anode part 3A, anode part 3B, anode part 3C, and anode part 3D.

[0117] A sealing resin 8 is filled between the anode portions.

[0118] exist Figure 4 The cathode 7 is exposed at the second end surface 9b of the resin molded body 9. The cathode of one capacitor element is exposed in four parts, and the exposed cathodes are shown as cathode part 7A, cathode part 7B, cathode part 7C, and cathode part 7D.

[0119] A sealing resin is filled between the cathode portions.

[0120] Hereinafter, the structure of the external electrodes included in the electrolytic capacitor according to the first embodiment of the present invention will be described in detail.

[0121] The first external electrode and the second external electrode in the electrolytic capacitor of the present invention may be external electrodes having a resin electrode layer containing a conductive component and a resin component, and the structure of other plating layers is not essential, but the following reference Figure 2 The first external electrode and the second external electrode including the inner plating layer, the resin electrode layer, and the outer plating layer will be described.

[0122] also, Figure 2 The resin electrode layer shown is a printed resin electrode layer formed by screen printing of an electrode paste.

[0123] exist Figure 2 2 shows the layer structure of the first external electrode 11 and the second external electrode 13 included in the electrolytic capacitor 1 .

[0124] The first external electrode 11 includes an inner plating layer 11a, a resin electrode layer 11b, and an outer plating layer 11c. The inner plating layer 11a includes a Ni plating layer 11a1 and an Ag plating layer 11a2. The outer plating layer 11c includes a Ni plating layer 11c1 and a Sn plating layer 11c2. The resin electrode layer 11b includes an Ag printed resin electrode layer 11b1.

[0125] The second external electrode 13 includes an inner plating layer 13a, a resin electrode layer 13b, and an outer plating layer 13c. The inner plating layer 13a includes a Ni plating layer 13a1 and an Ag plating layer 13a2. The outer plating layer 13c includes a Ni plating layer 13c1 and a Sn plating layer 13c2. The resin electrode layer 13b includes an Ag printed resin electrode layer 13b1.

[0126] Preferably, the Ni plating layers 11a1 and 13a1 of the inner plating layers 11a and 13a are formed by zincate treatment. That is, the surface of the aluminum foil of the anode 3 exposed from the first end face of the resin molded body 9 is alkali-etched to remove the oxide film of the anode 3, and then Zn plating is performed.

[0127] The zincate treatment is preferably performed by both mono-zincate (alkali washing) and di-zincate (stripping). Alternatively, the zincate treatment may be performed by acid etching.

[0128] Next, displacement plating is performed by electroless Ni plating to form Ni plating layers 11 a 1 and 13 a 1 .

[0129] The Ag plating layers 11a2 and 13a2 of the inner plating layer are formed to prevent oxidation of the Ni plating layers 11a1 and 13a1, and to continuously perform Ag plating without the plating layers after electroless Ni plating coming into contact with the atmosphere.

[0130] In addition, regarding the formation of the inner plating layer, in addition to performing electrolytic Ag plating after the zincate treatment as described above, an Ag plating layer may be formed by performing electroless Ag plating after the zincate treatment. Furthermore, a Cu plating layer may be formed by performing electroless Cu plating after the zincate treatment. Since the Cu plating layer is less susceptible to oxidation than the Ni plating layer, an Ag plating layer may not be formed thereon.

[0131] The resin electrode layers 11 b and 13 b contain a conductive component and a resin component.

[0132] As the conductive component, it is preferable that Ag, Cu, Ni, Sn, etc. are contained as a main component, and as the resin component, it is preferable that epoxy resin, phenol resin, etc. are contained as a main component.

[0133] Preferably, the resin electrode layer contains 67 wt % or more and 97 wt % or less of the conductive component, and contains 3 wt % or more and 33 wt % or less of the resin component.

[0134] Furthermore, it is more preferable that the conductive component is contained in an amount of 72% by weight or more and 95% by weight or less, and the resin component is contained in an amount of 5% by weight or more and 28% by weight or less.

[0135] Furthermore, it is more preferable that the conductive component is contained in an amount of 78% by weight or more and 95% by weight or less, and the resin component is contained in an amount of 5% by weight or more and 22% by weight or less.

[0136] Furthermore, it is more preferable that the conductive component is contained in an amount of 79% by weight or more and 89% by weight or less, and the resin component is contained in an amount of 11% by weight or more and 21% by weight or less.

[0137] In addition, the resin electrode layer is preferably a printed resin electrode layer formed by screen printing of an electrode paste. Here, the electrode paste is an Ag electrode paste containing an Ag filler containing Ag as a conductive component and a resin, and is more preferably an Ag printed resin electrode layer formed by screen printing.

[0138] When the resin electrode layer is a printed resin electrode layer, the external electrode can be made flatter than when the electrode paste is formed by dipping. That is, the uniformity of the film thickness of the first external electrode and the second external electrode is improved.

[0139] In such Figure 2 In the cross-sectional view shown in FIG. 1 , when the flatness of the first external electrode and the second external electrode is measured, the deviation of the thickness of the first external electrode measured from the first end surface of the resin molded body and the deviation of the thickness of the second external electrode measured from the second end surface of the resin molded body are preferably 10 μm or less. In addition, the deviation of the thickness is more preferably 8 μm or less. Furthermore, the deviation of the thickness is further preferably 5 μm or less.

[0140] Furthermore, when the resin electrode layer is a printed resin electrode layer formed by screen printing of an electrode paste, it is preferred that the electrode paste contains 60 wt % or more and 95 wt % or less of a conductive component and 3 wt % or more and 30 wt % or less of a resin component.

[0141] Furthermore, it is more preferable that the conductive component is contained in an amount of 65% by weight or more and 90% by weight or less, and the resin component is contained in an amount of 5% by weight or more and 25% by weight or less.

[0142] Furthermore, it is more preferable that the conductive component is contained in an amount of 70% by weight or more and 90% by weight or less, and the resin component is contained in an amount of 5% by weight or more and 20% by weight or less.

[0143] Furthermore, it is more preferable that the conductive component is contained in an amount of 75% by weight or more and 85% by weight or less, and the resin component is contained in an amount of 10% by weight or more and 20% by weight or less.

[0144] The electrode paste may contain an organic solvent, and a glycol ether-based solvent is preferably used as the organic solvent, for example, diethylene glycol monobutyl ether, diethylene glycol monophenyl ether, etc. may be mentioned.

[0145] Furthermore, less than 5% by weight of additives may be used as necessary. Additives are useful for adjusting the rheological properties, particularly the thixotropy, of the electrode paste.

[0146] The Ni plating layers 11c1 and 13c1 of the outer plating layers 11c and 13c are mainly formed to improve moisture resistance, and the Sn plating layers 11c2 and 13c2 are mainly formed to improve solderability.

[0147] The first external electrode 11 includes a first upper surface lead portion 11 b 2 extending the first external electrode 11 to the upper surface 9 d of the resin molded body 9 and a first bottom surface lead portion 11 b 3 extending the first external electrode 11 to the bottom surface 9 c of the resin molded body 9 .

[0148] The second external electrode 13 has a second upper surface lead portion 13 b 2 extending the second external electrode 13 to the upper surface 9 d of the resin molded body 9 , and a second bottom surface lead portion 13 b 3 extending the second external electrode 13 to the bottom surface 9 c of the resin molded body 9 .

[0149] The dimensions of the first upper surface lead-out portion 11 b 2 , the second upper surface lead-out portion 13 b 2 , and the first bottom surface lead-out portion 11 b 3 , and the second bottom surface lead-out portion 13 b 3 can be appropriately adjusted according to the conditions of screen printing.

[0150] In addition, in the formation of the external electrodes of the electrolytic capacitor described later, when the Ag electrode paste serving as the electrode paste is screen-printed onto the first end face (second end face) of the resin molded body, the direction of printing can be changed by printing in the direction from the bottom surface side of the first end face (second end face) toward the upper surface side, or printing in the direction from the upper surface side toward the bottom surface side. The sizes of the first upper surface lead-in portion 11b2 (second upper surface lead-in portion 13b2) and the first bottom surface lead-in portion 11b3 (second bottom surface lead-in portion 13b3).

[0151] In order to make the size of the first bottom lead-out portion 11b3 and the second bottom lead-out portion 13b3 larger than the size of the first upper surface lead-out portion 11b2 and the second upper surface lead-out portion 13b2, the printing direction is preferably printed in the direction from the bottom surface side of the first end face toward the upper surface side. Alternatively, the printing direction may be the width direction (W direction) of the resin molded body, and the size of the first upper surface lead-out portion 11b2 and the second upper surface lead-out portion 13b2 may be formed to be the same as the size of the first bottom lead-out portion 11b3 and the second bottom lead-out portion 13b3.

[0152] In the electrolytic capacitor of the present invention, preferably, a third external electrode electrically connected to the first external electrode and a fourth external electrode electrically connected to the second external electrode are provided on the bottom surface of the resin molded body.

[0153] exist Figure 1 as well as Figure 2 The electrolytic capacitor 1 shown includes a third external electrode 15 formed on the bottom surface 9 c of the resin molded body 9 and electrically connected to the first external electrode 11 , and a fourth external electrode 17 formed on the bottom surface 9 c of the resin molded body 9 and electrically connected to the second external electrode 13 .

[0154] The third external electrode 15 includes a Cu pattern electrode layer 15a as a metal pattern electrode layer provided on the bottom surface 9c of the resin molded body 9. Furthermore, an Au plated layer 15b as a metal plated layer is provided on the Cu pattern electrode layer 15a. Although not shown in the figure, a Ni plated layer may be formed between the Cu pattern electrode layer 15a and the Au plated layer 15b.

[0155] The fourth external electrode 17 includes a Cu pattern electrode layer 17a as a metal pattern electrode layer provided on the bottom surface 9c of the resin molded body 9. Furthermore, an Au plated layer 17b as a metal plated layer is provided on the Cu pattern electrode layer 17a.

[0156] The Cu pattern electrode layers 15 a and 17 a can be formed into a desired shape by forming a Cu layer on the support substrate 9 g in advance and etching the Cu layer.

[0157] The Au plated layers 15 b and 17 b are formed to prevent oxidation of the Cu pattern electrode layers 15 a and 17 a.

[0158] The thickness of the metal pattern electrode layer is preferably 10 μm or more and preferably 25 μm or less (a typical value is 15 μm).

[0159] The thickness of the Au plating layer is preferably 20 nm or more and preferably 50 nm or less (a typical value is 30 nm). The thickness of the Ni plating layer is preferably 2 μm or more and preferably 5 μm or less (a typical value is 3 μm).

[0160] A Ni plating layer and a Sn plating layer are further formed on the Au plating layers 15 b and 17 b . The Ni plating layer and the Sn plating layer are formed continuously with the outer plating layers 11 c and 13 c of the first external electrode 11 and the second external electrode 13 .

[0161] The Ni plating layer and the Sn plating layer on the Au plating layers 15 b and 17 b are parts of the third external electrode 15 and the fourth external electrode 17 , respectively.

[0162] Preferably, the length of the third external electrode is longer than the length of the first upper surface winding portion of the first external electrode wound around the upper surface of the resin molded body, and the length of the fourth external electrode is longer than the length of the second upper surface winding portion of the second external electrode wound around the upper surface of the resin molded body.

[0163] In addition, preferably, the thickness of the third external electrode is thicker than the thickness of the first upper surface winding portion of the first external electrode wound around the upper surface of the resin molded body, and the thickness of the fourth external electrode is thicker than the thickness of the second upper surface winding portion of the second external electrode wound around the upper surface of the resin molded body.

[0164] These relationships are described below with reference to the drawings.

[0165] Figure 5 It is a side view schematically showing the dimensional relationship at the LT surface of the electrolytic capacitor.

[0166] exist Figure 5 Only the resin molded body 9 and the first external electrode 11 , the second external electrode 13 , the third external electrode 15 , and the fourth external electrode 17 of the electrolytic capacitor 1 are shown.

[0167] exist Figure 5 In the figure, the length of the third external electrode 15 is indicated by a double arrow E15, and the length of the first upper surface lead-in portion of the first external electrode 11 is indicated by a double arrow E11. In addition, the thickness of the third external electrode 15 is indicated by a double arrow T15, and the thickness of the first upper surface lead-in portion of the first external electrode 11 is indicated by a double arrow T11.

[0168] Furthermore, the length of the fourth external electrode 17 is indicated by a double arrow E17, and the length of the second upper surface lead-out portion of the second external electrode 13 is indicated by a double arrow E13. In addition, the thickness of the fourth external electrode 17 is indicated by a double arrow T17, and the thickness of the second upper surface lead-out portion of the second external electrode 13 is indicated by a double arrow T13.

[0169] In the case shown in this way, E15>E11, E17>E13, and T15>T11, T17>T13.

[0170] Since the third external electrode 15 and the fourth external electrode 17 are relatively long or thick, they can be suitably used as electrodes for mounting an electrolytic capacitor.

[0171] On the other hand, the upper surface lead-out portion of the first external electrode 11 and the second external electrode 13 does not function as an electrode for mounting. Therefore, the thickness of the electrolytic capacitor can be reduced by reducing the thickness of this portion. Since the allowable size (allowable thickness) of the chip component as an electrolytic capacitor is determined, if the thickness of the upper surface lead-out portion can be reduced, the thickness of the laminate portion can be relatively thickened, and the capacitance of the capacitor can be increased.

[0172] In addition, Figure 5 In FIG. 1 , the length of the electrolytic capacitor 1 is indicated by a double arrow L, and the thickness is indicated by a double arrow T.

[0173] Furthermore, the length dimensions of the side lead-out portions of the first external electrode 11 and the second external electrode 13 are indicated by double-headed arrows WL11 and WL13 .

[0174] Figure 6It is a top view schematically showing the dimensional relationship at the LW plane of the electrolytic capacitor.

[0175] Figure 6 This is a diagram of the electrolytic capacitor 1 as viewed from the top surface, and therefore shows the first external electrode 11 and the second external electrode 13 , as well as the top surface lead-out portions of the first external electrode 11 and the second external electrode 13 .

[0176] exist Figure 6 In addition to Figure 5 In addition to the dimensions shown, the double arrow W also indicates the width of the electrolytic capacitor 1 .

[0177] Furthermore, the thickness dimensions of the side lead-out portions of the first external electrode 11 and the second external electrode 13 are indicated by double arrows WT11 and WT13, and the thickness at the first end surface or the second end surface of the first external electrode 11 and the second external electrode 13 are indicated by double arrows L11 and L13.

[0178] Figure 7 It is a bottom view schematically showing the dimensional relationship at the LW plane of the electrolytic capacitor.

[0179] Figure 7 This is a diagram of the electrolytic capacitor 1 as viewed from the bottom surface, and therefore shows the third external electrode 15 and the fourth external electrode 17 .

[0180] right Figure 6 and Figure 7 By comparison, the length of the third external electrode 15, that is, the length of the double arrow E15, and the length of the fourth external electrode 17, that is, the length of the double arrow E17, become shorter than Figure 6 The lengths E11 and E13 of the upper surface lead-out portions of the first external electrode 11 and the second external electrode 13 shown are long.

[0181] That is, the area of ​​the external electrode at the bottom surface of the electrolytic capacitor is increased, and it can be said that the external electrode is suitable for mounting the electrolytic capacitor.

[0182] Figure 8 It is a side view (end view) schematically showing the dimensional relationship at the WT plane of the electrolytic capacitor.

[0183] Figure 8 Although the electrolytic capacitor 1 is shown as a diagram viewed from the first end surface side, the same diagram is also provided when viewed from the second end surface side.

[0184] exist Figure 8 The thickness of the third external electrode 15 and the fourth external electrode 17 , that is, the thickness indicated by double-headed arrows T15 and T17 , is shown to be thicker than the thicknesses T11 and T13 of the upper surface lead-out portions of the first external electrode 11 and the second external electrode 13 .

[0185] Examples of preferred ranges of the dimensions shown in the above-mentioned drawings are as follows.

[0186] Size of electrolytic capacitors

[0187] L size: 3.4mm or more and 3.8mm or less, the typical value is 3.5mm

[0188] W size: 2.7mm or more and 3.0mm or less, the typical value is 2.8mm

[0189] T size: 1.8mm or more and 2.0mm or less, the typical value is 1.9mm

[0190] External electrode dimensions

[0191] L11, L13 dimensions (end surface thickness of the first and second external electrodes): 0.005 mm or more and 0.06 mm or less, with a typical value of 0.02 mm

[0192] E11, E13 dimensions (length of the upper surface lead-in portion): 0.005 mm or more and 0.15 mm or less, with a typical value of 0.1 mm

[0193] E15, E17 size (3rd, 4th external electrode length): 0.3mm or more and 0.7mm or less, the typical value is 0.5mm

[0194] WT11, WT13 dimensions (thickness of the side lead-in portion of the first and second external electrodes): 0.005 mm or more and 0.02 mm or less, with a typical value of 0.01 mm

[0195] WL11, WL13 dimensions (length of the side lead-out portion of the first and second external electrodes): 0.01 mm or more and 0.15 mm or less, with a typical value of 0.05 mm

[0196] T11, T13 dimensions (top surface lead-in thickness): 0.002mm or more and 0.015mm or less, with a typical value of 0.005mm

[0197] T15, T17 dimensions (3rd and 4th external electrode thickness): 0.01mm or more and 0.15mm or less, with a typical value of 0.05mm

[0198] Furthermore, it is preferable that the first and third external electrodes and the second and fourth external electrodes each have an L-shape when the electrolytic capacitor is viewed from the side.

[0199] This is based on Figure 5 The shape of the external electrodes shown can be clearly seen.

[0200] The first external electrode 11 and the third external electrode 15 are formed on the first end surface 9a and the bottom surface 9c of the resin molded body 9, thereby having an L shape. In addition, the second external electrode 13 and the fourth external electrode 17 are formed on the second end surface 9b and the bottom surface 9c of the resin molded body 9, thereby having an L shape.

[0201] In addition, the so-called L-shaped external electrodes means that the external electrodes are mainly formed on the two end surfaces and the bottom surface of the resin molded body 9, such as Figure 5 As shown in FIG. 1 and FIG. 2 , external electrodes may be formed on surfaces other than the two end surfaces and the bottom surface of the resin molded body 9 in the form of upper surface lead-out portions and side surface lead-out portions, but these are included in the L-shape.

[0202] The lengths of the upper surface lead-out portions of the first and second external electrodes are short, whereas the lengths of the third and fourth external electrodes are long, so that the external electrodes as a whole appear to be L-shaped.

[0203] In addition, since the lengths of the side lead-out portions of the first external electrode and the second external electrode are short, they do not affect the determination of whether or not the electrodes are in an L-shape.

[0204] The electrolytic capacitor according to the first embodiment of the present invention described above can be manufactured by, for example, the following method.

[0205] [Fabrication of capacitor elements]

[0206] A valve-acting metal foil such as aluminum foil having a porous layer such as an etching layer on the surface is prepared, and the surface of the porous layer is anodized to form a dielectric layer.

[0207] A solid electrolyte layer is formed on the dielectric layer by screen printing, and then a carbon layer is formed on the solid electrolyte layer by screen printing. Furthermore, a sheet is stacked or screen printed on the carbon layer to form a cathode lead layer.

[0208] Through the above steps, a capacitor element can be obtained.

[0209] [Lamination and resin sealing of capacitor elements]

[0210] A plurality of capacitor elements are stacked as a layered body, and sealed with a sealing resin by compression molding to form a resin molded body.

[0211] The laminate is preferably produced on a supporting substrate, and a metal pattern electrode layer that becomes a part of the third external electrode and the fourth external electrode is preferably provided in advance on the back surface of the supporting substrate.

[0212] Furthermore, it is preferable to provide an Au plating layer in advance on the metal pattern electrode layer.

[0213] in addition, Figure 3 as well as Figure 4 The resin molded body having the structure shown and with the anode portion and the cathode portion exposed can be obtained by the manufacturing method described in Japanese Patent Application Publication No. 2019-79866.

[0214] The method for manufacturing the resin molded body comprises: a process of preparing a first sheet; a process of preparing a second sheet; a process of covering the first sheet with an insulating material; a process of forming a conductive layer on the first sheet; a process of making a stacked sheet; a process of sealing with a sealing resin to make a stacked block; and a process of making a plurality of resin molded bodies by cutting the stacked block.

[0215] The first sheet is a sheet including a valve-acting metal substrate having a dielectric layer formed on the surface thereof and a solid electrolyte layer provided on the dielectric layer, and the second sheet is a sheet made of a metal foil.

[0216] The first sheet and the second sheet have through holes at the first end face or the second end face of the resin molded body, respectively, and the through holes are connected when the laminate is made. Then, when the sealing is performed by the sealing resin, the through holes are filled with the sealing resin to produce a laminated block. The laminated block is cut to separate the sealing resin sealed in the through holes, thereby obtaining a resin molded body.

[0217] In this resin molded body, the anode is separated into a plurality of anode parts and exposed by the sealing resin sealed in the through hole. Also, the cathode is separated into a plurality of cathode parts and exposed by the sealing resin sealed in the through hole.

[0218] [Formation of external electrodes]

[0219] After Ag electrode paste is screen-printed on the first end surface of the resin molded body, it is thermally cured to form a first external electrode, which is electrically connected to a metal pattern electrode layer as a third external electrode provided on the bottom surface of the resin molded body.

[0220] Furthermore, after Ag electrode paste is screen-printed on the second end surface of the resin molded body, it is thermally cured to form a second external electrode, which is electrically connected to a metal pattern electrode layer as a fourth external electrode provided on the bottom surface of the resin molded body.

[0221] The Ag electrode paste contains a conductive component and a resin component, and the resin electrode layer formed in this way is a printed resin electrode layer.

[0222] Furthermore, the electrode paste used in this step preferably contains 60 wt % to 95 wt % of a conductive component and 3 wt % to 30 wt % of a resin component.

[0223] Furthermore, it is more preferable that the conductive component is contained in an amount of 65% by weight or more and 90% by weight or less, and it is more preferable that the resin component is contained in an amount of 5% by weight or more and 25% by weight or less.

[0224] Furthermore, it is more preferable that the conductive component is contained in an amount of 70% by weight or more and 90% by weight or less, and it is more preferable that the resin component is contained in an amount of 5% by weight or more and 20% by weight or less.

[0225] Furthermore, it is more preferable that the conductive component is contained in an amount of 75% by weight or more and 85% by weight or less, and it is more preferable that the resin component is contained in an amount of 10% by weight or more and 20% by weight or less.

[0226] The electrode paste may contain an organic solvent, and a glycol ether-based solvent is preferably used as the organic solvent, for example, diethylene glycol monobutyl ether, diethylene glycol monophenyl ether, etc. may be mentioned.

[0227] Furthermore, additives in an amount of less than 5% by weight may be used as necessary.

[0228] Preferably, zincate treatment is performed before screen printing of the Ag electrode paste, and zincate treatment and displacement plating are performed to form a Ni plating layer as an inner plating layer.

[0229] Furthermore, it is preferable to form an Ag plating layer as an inner plating layer on the Ni plating layer.

[0230] Furthermore, it is preferable to form a Ni plating layer and a Sn plating layer as the outer plating layer.

[0231] The outer plating layer is formed on the printed resin electrode layer serving as the first external electrode and the second external electrode and on the third external electrode and the fourth external electrode.

[0232] The electrolytic capacitor of the present invention can be obtained through the above-mentioned steps.

[0233] Hereinafter, another embodiment of the electrolytic capacitor of the present invention will be described. The electrolytic capacitor of this embodiment is referred to as an electrolytic capacitor of a second embodiment.

[0234] The electrolytic capacitor of the second embodiment has the same structure as the electrolytic capacitor of the first embodiment except that the third external electrode and the fourth external electrode have a resin electrode layer containing a conductive component and a resin component instead of the metal pattern electrode layer and the Au plating layer.

[0235] Fig. 9 It is a cross-sectional view schematically showing an example of an electrolytic capacitor according to a second embodiment.

[0236] Fig. 9The electrolytic capacitor 2 shown has a resin electrode layer 15 c as the third external electrode 15 and a resin electrode layer 17 c as the fourth external electrode 17 .

[0237] Furthermore, Ni plating layers and Sn plating layers are further formed on the resin electrode layers 15 c and 17 c . The Ni plating layers and Sn plating layers are formed continuously with the outer plating layers 11 c and 13 c of the first external electrode 11 and the second external electrode 13 .

[0238] The Ni plating layer and the Sn plating layer on the resin electrode layers 15 c and 17 c are parts of the third external electrode 15 and the fourth external electrode 17 , respectively.

[0239] The structure other than the third external electrode and the fourth external electrode is the same as Figure 2 The electrolytic capacitor 1 shown has the same structure, so their detailed description is omitted.

[0240] As for the structure of the resin electrode layer, it is preferable to have a structure including a conductive component and a resin component similarly to the resin electrode layers 11 b and 13 b constituting the first external electrode 11 and the second external electrode 13 .

[0241] Furthermore, it is preferred that the resin electrode layer contains 67% by weight or more and 97% by weight or less of a conductive component, and contains 3% by weight or more and 33% by weight or less of a resin component.

[0242] Preferably, the resin electrode layers constituting the third external electrode and the fourth external electrode are printed resin electrode layers formed by screen printing an electrode paste on the bottom surface of the resin molded body.

[0243] More preferred is an Ag-printed resin electrode layer formed by screen printing of an Ag electrode paste containing Ag as a conductive component.

[0244] In addition, in the case where the resin electrode layer is a printed resin electrode layer formed by screen printing of an electrode paste relative to the bottom surface of a resin molded body, it is preferred that the electrode paste contains a conductive component in an amount of greater than 60 weight % and less than 95 weight %, and a resin component in an amount of greater than 3 weight % and less than 30 weight %.

[0245] Preferably, the third external electrode and the fourth external electrode are formed by, in order, forming a printed resin electrode layer, a Ni plating layer, and a Sn plating layer formed by screen printing on the bottom surface of the resin molded body.

[0246] The thickness of the printed resin electrode layer is preferably 5 μm or more and preferably 150 μm or less, and more preferably 100 μm or less.

[0247] A method for manufacturing an electrolytic capacitor according to a second embodiment of the present invention will be described.

[0248] In this case, a structure in which a metal pattern electrode layer is not provided on the back surface of the supporting substrate is used.

[0249] The steps up to the lamination of capacitor elements and resin sealing can be the same as those of the method for manufacturing the electrolytic capacitor of the first embodiment.

[0250] When forming the external electrodes, Ag electrode paste as electrode paste is screen-printed on the first end surface and the second end surface of the resin molded body, and then thermally cured to form the first external electrode and the second external electrode.

[0251] Next, Ag electrode paste as an electrode paste was screen-printed on the bottom surface of the resin molded body and then thermally cured to simultaneously form the third external electrode and the fourth external electrode as printed resin electrode layers.

[0252] In addition, as described above, although the third external electrode and the fourth external electrode can be simultaneously formed on the bottom surface of the resin molded body after the first external electrode and the second external electrode are formed on the first end surface and the second end surface of the resin molded body, the process can also be reversed, that is, the first external electrode and the second external electrode can be formed on the first end surface and the second end surface of the resin molded body after the third external electrode and the fourth external electrode are simultaneously formed on the bottom surface of the resin molded body.

[0253] Furthermore, it is preferable that the electrode paste used in this step contains 60 wt % or more and 95 wt % or less of a conductive component and 3 wt % or more and 30 wt % or less of a resin component.

[0254] Furthermore, it is more preferable that the conductive component is contained in an amount of 65% by weight or more and 90% by weight or less, and it is more preferable that the resin component is contained in an amount of 5% by weight or more and 25% by weight or less.

[0255] Furthermore, it is preferable that the conductive component is contained in an amount of 70% by weight or more and 90% by weight or less, and it is preferable that the resin component is contained in an amount of 5% by weight or more and 20% by weight or less.

[0256] Furthermore, it is more preferable that the conductive component is contained in an amount of 75% by weight or more and 85% by weight or less, and it is still more preferable that the resin component is contained in an amount of 10% by weight or more and 20% by weight or less.

[0257] The electrode paste may contain an organic solvent, and a glycol ether-based solvent is preferably used as the organic solvent, for example, diethylene glycol monobutyl ether, diethylene glycol monophenyl ether, etc. may be mentioned.

[0258] Furthermore, additives in an amount of less than 5% by weight may be used as necessary.

[0259] Furthermore, it is preferable to form a Ni plating layer and a Sn plating layer as the outer plating layer.

[0260] The outer plating layer is formed on the printed resin electrode layer serving as the first external electrode and the second external electrode, and on the printed resin electrode layer serving as the third external electrode and the fourth external electrode.

[0261] The electrolytic capacitor of the second embodiment of the present invention can be obtained through the above process. In addition, the electrolytic capacitor of the second embodiment does not have a metal pattern electrode layer on the back of the supporting substrate. Thus, before the resin electrode layer is screen-printed on the first end face and the second end face of the resin molded body, for example, there is no need to arrange a plurality of electrolytic capacitors in the direction from the bottom side toward the upper surface side in order to print. Furthermore, if a structure is set that does not require a supporting substrate, there is no need to distinguish between the upper surface and the bottom surface, so there is no need to arrange a plurality of electrolytic capacitors in the direction in order to make the printing direction consistent.

[0262] The electrolytic capacitors according to the above-described embodiments of the present invention are solid electrolytic capacitors having a solid electrolyte layer, but may be electrolytic capacitors using an electrolyte solution instead of a solid electrolyte or using an electrolyte solution together with a solid electrolyte.

[0263] Furthermore, the laminate including the capacitor element preferably includes a plurality of capacitor elements, but the capacitor element may be one.

[0264] [Example]

[0265] Hereinafter, examples in which the uniformity of the film thickness and the adhesion of the external electrodes were evaluated will be described with respect to the electrolytic capacitor of the present invention. However, the present invention is not limited to these examples.

[0266] The film thickness uniformity, adhesion, and ESR of the external electrodes were evaluated by the following procedures.

[0267] The compositions of the Ag electrode pastes of compositions No. 1 to No. 8 are shown in Table 1. The left column shows the composition ratio at 100 wt % of the Ag electrode paste, and the right column shows the composition ratio at 100 wt % of the printed electrode layer as the solid content excluding the organic solvent.

[0268] The sealing resin containing epoxy resin and silica particles is used to seal the Figure 1 as well as Figure 2After the laminated body of the structure shown in the figure is sealed to obtain a resin molded body, inner layer plating is performed, and Ag electrode paste is applied to the end faces (first end face and second end face) of the resin molded body by screen printing, and thermally cured at a drying temperature of 150 to 200° C. In addition, Ag electrode paste is applied to the bottom face of the resin molded body by screen printing, and thermally cured at a drying temperature of 150 to 200° C. Then, outer layer plating is formed, thereby forming the first external electrode, the second external electrode, the third external electrode, and the fourth external electrode.

[0269] Regarding the uniformity of film thickness, the thickness of the first external electrode and the second external electrode formed using the Ag electrode paste of each composition (see Figure 6 , Figure 7 Five locations (indicated by the double arrows L11, L13) were measured and the standard deviation σ was calculated. Evaluation was performed as follows: ◎: deviation is less than 5 μm, ○: deviation is less than 8 μm, △: deviation is less than 10 μm, and the results are shown in Table 1.

[0270] In addition, regarding the adhesion, after the solder paste was printed on the electrodes on the measurement substrate, the 3rd external electrode and the 4th external electrode of the electrolytic capacitor were placed and soldered and installed at 260°C in a reflow furnace. For the electrolytic capacitor obtained in this way, a load was applied to the LT surface of the electrolytic capacitor in the W direction to determine whether there was any damage to the appearance, cutting or peeling of the external electrode. The evaluation was performed as follows: ◎: more preferred, ○: preferred, △: no practical obstacle, as shown in Table 1.

[0271] In addition, as electrical characteristics, regarding ESR, the measurement terminals were touched to the first external electrode and the second external electrode formed using Ag electrode paste of each composition, and the ESR (mΩ) at 100 kHz was measured using an LCR meter. Evaluations were performed such as ◎: less than 30 mΩ, ○: less than 35 mΩ, and △: less than 40 mΩ, as shown in Table 1.

[0272] [Table 1]

[0273]

[0274] As shown in Table 1, the resin electrode layer including the conductive component and the resin component has high adhesion to the resin molded body, and all Examples have adhesion to a degree that does not cause problems in practical use.

[0275] Furthermore, the resin electrode layer is formed by screen printing of an electrode paste, thereby forming an external electrode having a high uniformity in film thickness.

[0276] Furthermore, the original electrical characteristics of the resin electrode layer having a high ratio of the conductive component are effectively utilized to reduce the ESR of the resin electrode layer.

[0277] Furthermore, by adjusting the ratio of the conductive component to the resin component in the conductive paste, the uniformity of the film thickness, the adhesion, and the ESR can be evaluated as a preferable evaluation or a more preferable evaluation.

Claims

1. A method for manufacturing an electrolytic capacitor, characterized in that: have: Step (A), forming a laminate including a capacitor element including an anode having a dielectric layer on its surface and a cathode facing the anode; Step (B), sealing the periphery of the stacked body with a sealing resin to form a resin molded body, the resin molded body being in a rectangular parallelepiped shape having a first end face, a second end face, an upper surface, and a bottom surface, wherein the anode is exposed from the first end face, and the cathode is exposed from the second end face; Step (C), screen printing the electrode paste on the first end surface in a direction from the bottom surface side toward the top surface side, while leading the electrode paste at least to the bottom surface; Step (D), screen-printing the electrode paste on the second end surface in a direction from the bottom surface side toward the upper surface side, while leading it at least to the bottom surface; and In step (E), the screen-printed electrode paste is thermally cured to form first and second external electrodes in which the respective portions on the respective surfaces of the resin molded body are integrated.

2. An electrolytic capacitor, characterized in that: have: A resin molded body, comprising a laminated body including a capacitor element and a sealing resin, wherein the capacitor element includes an anode having a dielectric layer on a surface and a cathode facing the anode, wherein the resin molded body is in a rectangular parallelepiped shape having a first end face and a second end face and an upper surface and a bottom surface, and the periphery of the laminated body is sealed by the sealing resin so that the anode is exposed from the first end face of the sealing resin and the cathode is exposed from the second end face of the sealing resin; a first external electrode electrically connected to the anode, each portion on each surface of the resin molded body being integrally formed by thermally curing the electrode paste, wherein in the length direction in which the first end surface and the second end surface face each other, the portion on the bottom surface is longer than the portion on the upper surface; as well as The second external electrode is electrically connected to the cathode, and each portion on each surface of the resin molded body is integrally formed by thermally curing the electrode paste, and the portion on the bottom surface is longer than the portion on the upper surface in the length direction.

3. The electrolytic capacitor according to claim 2, characterized in that: The first external electrode and the second external electrode include a resin electrode layer including a conductive component and a resin component. A variation in thickness of the first external electrode measured from the first end surface and a variation in thickness of the second external electrode measured from the second end surface are 10 μm or less.

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