Electrolytic capacitor

Abstract

An electrolytic capacitor (1) is provided with: a laminated body (30) in which a plurality of capacitor elements (20) are laminated, the laminated body (30) having a first surface (30a), the capacitor element (20) includes a valve action metal base (4) having a core portion (4a) and a porous portion (4b) formed along a surface of the core portion (4a), a dielectric layer (5) formed on the porous portion (4b), a solid electrolyte layer (7a) formed on the dielectric layer (5), and a conductive layer (7b) formed on the solid electrolyte layer (7a). A first conductive resin part (21) which is provided on the first surface (30a) of the laminate (30) and which is connected to the core part (4a) of the capacitor element (20); and a first lead frame (11) connected to the core part (4a) via the first conductive resin part (21).

Description

Technical Field

[0001] The present utility model relates to an electrolytic capacitor. Background Art

[0002] A solid electrolytic capacitor is disclosed in Patent Document 1.

[0003] In Embodiment 2 of the solid electrolytic capacitor disclosed in Patent Document 1, a structure in which three sheet-type solid electrolytic capacitors are stacked is described. The following structure is described: An anode lead-out body is exposed from each capacitor element, and a positive terminal is joined to the anode lead-out body by laser welding.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2001-85273 Summary of the Utility Model

[0007] Problems to be Solved by the Utility Model

[0008] The anode lead-out body of the solid electrolytic capacitor of Patent Document 1 is made of a valve metal. In addition, a member called a lead frame is used as the positive terminal. When the valve metal as the anode lead-out body and the lead frame as the positive terminal are welded as in Patent Document 1, the joint is hard and there is no flexibility at the joint portion. Therefore, the following problems sometimes occur: Due to the stress generated by the thermal expansion of each member during reflow soldering, the joint between the lead frame and the valve metal is disengaged, and the LC (leakage current) of the electrolytic capacitor increases.

[0009] The present utility model is completed to solve the above problems, and an object thereof is to provide an electrolytic capacitor that realizes electrical connection between a lead frame and a valve metal and realizes stress relaxation against stresses such as thermal stress.

[0010] Technical Solution for Solving the Problems

[0011] The electrolytic capacitor of the present utility model includes: a laminate in which a plurality of capacitor elements are laminated and which has a first surface, the capacitor element including a valve metal substrate having a core portion and a porous portion formed along the surface of the core portion, a dielectric layer formed on the porous portion, a solid electrolyte layer formed on the dielectric layer, and a conductive layer formed on the solid electrolyte layer; a first conductive resin portion provided on the first surface of the laminate and connected to the core portion of the capacitor element; and a first lead frame connected to the core portion via the first conductive resin portion.

[0012] Effects of the Utility Model

[0013] According to the present utility model, an electrolytic capacitor can be provided that realizes electrical connection between a lead frame and a valve-acting metal and realizes stress relaxation against stresses such as thermal stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 FIG. 1 is a perspective view schematically showing an example of the electrolytic capacitor of the present utility model.

[0015] Figure 2 FIG. 2 is a side view when observing the electrolytic capacitor shown in Figure 1 FIG. 1 from the first end face.

[0016] Figure 3 FIG. 3 is a bottom view of the electrolytic capacitor shown in Figure 1 FIG. 1.

[0017] Figure 4 FIG. 4 is a sectional view taken along line A-A of the electrolytic capacitor shown in Figure 1 FIG. 1.

[0018] Figure 5 FIG. 5 is a sectional view schematically showing the vicinity of the valve-acting metal substrate on the first surface of the laminate.

[0019] Figure 6 FIG. 6 is a process chart schematically showing a part of the manufacturing process of the electrolytic capacitor.

[0020] Figure 7 FIG. 7 is a process chart schematically showing a part of the manufacturing process of the electrolytic capacitor.

[0021] Figure 8A FIG. 8 is a process chart schematically showing a part of the manufacturing process of the electrolytic capacitor.

[0022] Figure 8B FIG. 9 is a process chart schematically showing a part of the manufacturing process of the electrolytic capacitor.

[0023] Figure 9A FIG. 10 is a process chart schematically showing a part of the manufacturing process of the electrolytic capacitor.

[0024] Figure 9B FIG. 11 is a process chart schematically showing a part of the manufacturing process of the electrolytic capacitor.

[0025] Figure 9C FIG. 12 is a process chart schematically showing a part of the manufacturing process of the electrolytic capacitor.

[0026] Figure 10 FIG. 13 is a sectional view taken along the LT plane of the electrolytic capacitor according to another embodiment.

[0027] Figure 11 FIG. 14 is a sectional view taken along the LT plane of the electrolytic capacitor according to another embodiment.

[0028] Figure 12 is schematically shown Figure 11 a process chart showing a part of the manufacturing process of the electrolytic capacitor shown. Detailed Description of the Invention

[0029] Hereinafter, the solid electrolytic capacitor of the present invention will be described.

[0030] However, the present invention is not limited to the following structure and can be appropriately modified and applied within the scope of not changing the gist of the present invention. It should be noted that a structure obtained by combining two or more of the following preferred structures of the present invention is also the present invention.

[0031] The electrolytic capacitor of the present invention includes: a laminate in which a plurality of capacitor elements are laminated and which has a first surface, the capacitor element including a valve-acting metal substrate having a core portion and a porous portion formed along the surface of the core portion, a dielectric layer formed on the porous portion, a solid electrolyte layer formed on the dielectric layer, and a conductive layer formed on the solid electrolyte layer; a first conductive resin portion provided on the first surface of the laminate and connected to the core portion of the capacitor element; and a first lead frame connected to the core portion via the first conductive resin portion.

[0032] Figure 1 is a perspective view schematically showing an example of the electrolytic capacitor of the present invention, Figure 2 is viewed from the first end face Figure 1 a side view when observing the electrolytic capacitor shown, Figure 3 is Figure 1 a bottom view of the electrolytic capacitor shown.

[0033] Figure 1 , Figure 2 and Figure 3 show the electrolytic capacitor 1.

[0034] The electrolytic capacitor 1 is generally rectangular parallelepiped in shape and has a length direction (L direction), a width direction (W direction), and a thickness direction (T direction).

[0035] The electrolytic capacitor 1 has a first end face 1a and a second end face 1b opposed to each other in the length direction as its outer surfaces. The electrolytic capacitor 1 has a bottom face 1c and an upper face 1d opposed to each other in the thickness direction as its outer surfaces. In addition, the electrolytic capacitor 1 has a first side face 1e and a second side face 1f opposed to each other in the width direction as its outer surfaces.

[0036] Note that in this specification, the surfaces of the electrolytic capacitor along the length direction (L direction) and the thickness direction (T direction) are referred to as LT surfaces, the surfaces along the length direction (L direction) and the width direction (W direction) are referred to as LW surfaces, and the surfaces along the width direction (W direction) and the thickness direction (T direction) are referred to as WT surfaces.

[0037] A first lead frame 11 is formed on the first end face 1a of the electrolytic capacitor 1, and a second lead frame 13 is formed on the second end face 1b. In addition, the first lead frame 11 is continuously formed within the range from the first end face 1a to the bottom face 1c of the electrolytic capacitor 1, and the second lead frame 13 is continuously formed within the range from the second end face 1b to the bottom face 1c of the electrolytic capacitor 1.

[0038] In the electrolytic capacitor 1, a laminate ([[]] Figure 1 not shown in the figure) in which a plurality of capacitor elements are laminated is sealed by a sealing resin 8, and a resin molded body 9 having a rectangular parallelepiped shape with the surface of the sealing resin 8, the surface of the first lead frame 11, and the surface of the second lead frame 13 as outer surfaces is formed.

[0039] The surface of the first lead frame 11 and the surface of the sealing resin 8 together constitute the first end face 1a of the electrolytic capacitor 1 (see Figure 2 ). In addition, the surface of the second lead frame 13 and the surface of the sealing resin 8 together constitute the second end face 1b of the electrolytic capacitor 1.

[0040] Furthermore, the surface of the first lead frame 11, the surface of the sealing resin 8, and the surface of the second lead frame 13 together constitute the bottom face 1c of the electrolytic capacitor 1 (see Figure 3 ).

[0041] Note that in the electrolytic capacitor of the present invention, it is preferable that the laminate is sealed by a sealing resin, and a resin molded body having a rectangular parallelepiped shape with the surface of the sealing resin and the surface of the first lead frame as outer surfaces is formed. In addition, in the electrolytic capacitor of the present invention, it is preferable that the laminate is sealed by a sealing resin, and a resin molded body having a rectangular parallelepiped shape with the surface of the sealing resin, the surface of the first lead frame, and the surface of the second lead frame as outer surfaces is formed.

[0042] The shape of the electrolytic capacitor of the present invention and the shape of the resin molded body constituting the electrolytic capacitor of the present invention are not particularly limited, and any three-dimensional shape can be adopted. The shape of the electrolytic capacitor and the shape of the resin molded body are preferably rectangular parallelepiped shapes. In addition, the rectangular parallelepiped shape does not mean a perfect rectangular parallelepiped, and the surfaces forming the electrolytic capacitor and the resin molded body may not be orthogonal to other surfaces and may have a taper, or may be a chamfered shape.

[0043] Figure 4 Yes Figure 1A-A line cross-sectional view of the electrolytic capacitor shown.

[0044] The capacitor element 20 includes: a valve-action metal substrate 4 having a core portion and a porous portion formed on the surface of the core portion; a dielectric layer 5 formed on the porous portion; a solid electrolyte layer 7a formed on the dielectric layer 5; and a conductive layer 7b (carbon layer 7b1 and metal layer 7b2) formed on the solid electrolyte layer 7a.

[0045] A plurality of capacitor elements 20 are laminated to form a laminate 30, and the periphery of the laminate 30 is sealed with a sealing resin 8 to form a resin molded body 9. In the laminate 30, the laminated capacitor elements 20 may also be joined to each other via a conductive adhesive (not shown).

[0046] Examples of the valve-action metal constituting the valve-action metal substrate include metal monomers such as aluminum, tantalum, niobium, titanium, zirconium, magnesium, and silicon, or alloys including these metals. Among them, aluminum or an aluminum alloy is preferred.

[0047] The shape of the valve-action metal substrate is not particularly limited, but a flat plate shape is preferred, and a foil shape is more preferred. In addition, the porous portion is preferably an etched layer obtained by etching treatment with hydrochloric acid or the like.

[0048] The thickness of the valve-action metal substrate before etching is preferably 60 μm or more and preferably 180 μm or less. In addition, the thickness of the unetched valve-action metal substrate (core portion) after the etching treatment is preferably 10 μm or more and preferably 70 μm or less. The thickness of the porous portion is designed in accordance with the withstand voltage and capacitance required for the electrolytic capacitor, but the combined thickness of the porous portions on both sides of the valve-action metal substrate is preferably 10 μm or more and preferably 120 μm or less.

[0049] The dielectric layer is preferably composed of an oxide coating film of the above valve-action metal. For example, when an aluminum foil is used as the valve-action metal substrate, an oxide coating film that becomes the dielectric layer can be formed by anodizing in an aqueous solution including boric acid, phosphoric acid, adipic acid, or their sodium salts, ammonium salts, etc.

[0050] The dielectric layer is formed with pores (recesses) by being formed along the surface of the porous portion. The thickness of the dielectric layer is designed in accordance with the withstand voltage and capacitance required for the electrolytic capacitor, but is preferably 3 nm or more and preferably 200 nm or less.

[0051] On the anode side end of the capacitor element 20, a mask layer 40 is provided around the valve-acting metal substrate 4 and the dielectric layer 5. A part of the surface of the mask layer 40 and the surfaces of the core part and the porous part of the valve-acting metal substrate 4 together constitute the first surface 30a of the laminate 30. The first surface 30a of the laminate 30 corresponds to the first end face 1a of the electrolytic capacitor 1. The first surface 30a of the laminate 30 is the anode side end face of the laminate.

[0052] On the first surface 30a of the laminate 30, a first conductive resin part 21 connected to each core part of the capacitor element 20 is provided. Since the first conductive resin parts 21 connected to each core part of the capacitor element 20 are formed integrally, the anodes of the plurality of capacitor elements 20 are collected in the first conductive resin part 21.

[0053] The first conductive resin part 21 is also connected to the first lead frame 11. Since the first conductive resin part 21 is connected to the core part of the capacitor element 20 and the first lead frame 11, the first lead frame 11 is connected to the core part of the capacitor element 20 via the first conductive resin part 21.

[0054] In the electrolytic capacitor of the present utility model, the first lead frame and the core part of the capacitor element are not welded but connected via the first conductive resin part. The connection via the first conductive resin part is a connection based on resin, so it is a joining method in which the joined part is softer than welding. Therefore, the occurrence of defective conditions caused by the separation of the joint between the first lead frame and the core part due to the stress generated by the thermal expansion of each member during reflow soldering is prevented.

[0055] In addition, since the first conductive resin part is made of a conductive material, the electrical connection between the first lead frame and the core part is also ensured. Based on the above situation, the electrolytic capacitor of the present utility model becomes an electrolytic capacitor that realizes the electrical connection between the first lead frame and the valve-acting metal and realizes stress relaxation against stresses such as thermal stress.

[0056] As the first lead frame, it is possible to use aluminum, copper, nickel, chromium, cobalt, or an alloy including them, etc.

[0057] The first conductive resin part is preferably a conductive resin electrode layer including a conductive component and a resin component.

[0058] As the conductive component, it is preferably to include Ag, Cu, Ni, Sn, etc. as the main components, and as the resin component, it is preferably to include epoxy resin, phenolic resin, etc. as the main components.

[0059] In particular, it is preferably that the first conductive resin part includes Ag. When it is a conductive resin electrode layer including Ag, since the resistivity of Ag is small, the ESR can be reduced.

[0060] In addition, the first conductive resin portion is preferably a printed resin electrode layer formed by screen printing an electrode paste. When the first conductive resin portion is a printed resin electrode layer, the first conductive resin portion can be made flatter than in the case of forming an electrode layer by impregnating an electrode paste.

[0061] Alternatively, instead of screen printing, the first conductive resin portion can be formed by applying an electrode paste using a dispenser.

[0062] The electrode paste for forming the first conductive resin portion may also include an organic solvent. As the organic solvent, a glycol ether-based solvent is preferably used. For example, diethylene glycol monobutyl ether, diethylene glycol monophenyl ether, etc. are cited.

[0063] In addition, additives can also be used as needed. The additives are useful for adjusting the rheology, especially the thixotropy, of the electrode paste.

[0064] Preferably, on the first surface of the laminate, a contact layer that is in direct contact with the core portion is provided, and the core portion is connected to the first conductive resin portion via the contact layer.

[0065] Hereinafter, the manner in which the core portion is connected to the first conductive resin portion via the contact layer will be described.

[0066] Figure 5 It is a schematic cross-sectional view showing the vicinity of the valve-acting metal substrate on the first surface of the laminate.

[0067] Figure 5 It is also a schematic cross-sectional view showing Figure 4 the region surrounded by the dashed line B in the lower right part of

[0068] The valve-acting metal substrate 4 has a core portion 4a and a porous portion 4b formed along the surface of the core portion 4a. The end portion of the valve-acting metal substrate 4 is exposed on the first surface 30a of the laminate 30.

[0069] A dielectric layer 5 is formed on the surface of the porous portion 4b.

[0070] Figure 5 The contact layer 31 that is in direct contact with the core portion 4a is shown. The first conductive resin portion 21 exists around the contact layer 31, and the core portion 4a is connected to the first conductive resin portion 21 via the contact layer 31.

[0071] The contact layer 31 is preferably an electrode layer including at least one selected from the group consisting of Cu, Ni, Sn, Ag, Zn, and Au, and is preferably an electrode layer made of Cu.

[0072] By providing a contact layer, the connectivity between the core part and the first conductive resin part can be improved. For example, when the core part is made of aluminum and the main component of the conductive component contained in the first conductive resin part is Ag, the connectivity of the connection method via other materials is sometimes higher than that of the method of directly connecting aluminum and Ag. For example, when Cu or Zn is used for the contact layer and aluminum and Ag are connected via Cu or Zn, the connectivity between the core part made of aluminum and the first conductive resin part including Ag can be improved.

[0073] In addition, the thickness of the contact layer 31 formed at the part of the core part 4a is preferably thicker than the thickness of the contact layer 31 formed at the part of the porous part 4b.

[0074] The thickness of the contact layer 31 is determined as the thickness of the contact layer 31 in the normal direction of the first surface 30a of the laminate 30. In addition, the thickness of the contact layer 31 formed on the core part 4a of the valve-acting metal substrate 4 and the porous part 4b of the valve-acting metal substrate 4 is determined as the thickness at the thickest position in each part. In Figure 5 FIG. 8, the thicknesses of the contact layer 31 formed on the core part 4a of the valve-acting metal substrate 4 and the porous part 4b of the valve-acting metal substrate 4 are shown by double arrows T1 and T2, respectively.

[0075] The directions indicated by the double arrows T1 and T2 are the normal direction of the first surface 30a of the laminate 30.

[0076] When forming the contact layer 31 on the first surface 30a of the laminate 30, it is easy to form the contact layer 31 on the core part 4a, and it is difficult to form the contact layer 31 on the porous part 4b which is more brittle than the core part 4a. Therefore, the thickness of the contact layer 31 becomes thicker on the core part 4a.

[0077] When the thickness of the contact layer becomes thicker on the core part, compared with the case where the contact layer is flat, the contact area with the first conductive resin part formed on the contact layer increases, and the adhesion to the first conductive resin part is improved. Therefore, the ESR can be sufficiently reduced.

[0078] In addition, since the connection strength between the contact layer and the first conductive resin part is high, the terminal fixing strength when the electrolytic capacitor is installed can also be improved.

[0079] The thickness of the contact layer formed on the core part is preferably 0.3 μm or more and 30 μm or less. When the thickness of the contact layer is within the above range, the ESR can be further reduced, and the terminal fixing strength when the electrolytic capacitor is installed can be further improved.

[0080] The contact layer is preferably a layer formed by aerosol deposition method. In the aerosol deposition method, metal fine particles are ejected from a nozzle provided at the front end of an aerosol generator and collide with the first surface of the laminate, thereby becoming the contact layer.

[0081] In the aerosol deposition method, the oxide film on the surface of the metal constituting the core is removed by the collision of the aerosol with the core, the metal is exposed, and the contact layer is joined to the exposed metal. In the aerosol deposition method, the removal of the oxide film and the joining of the contact layer are continuously performed in a non-oxidizing atmosphere, so that the formation of an oxide film at the joining interface between the contact layer and the core can be prevented. Moreover, since the resistance at the joining interface between the contact layer and the core is low, the ESR of the electrolytic capacitor can be reduced.

[0082] Especially when the valve action metal substrate is aluminum, an oxide film is likely to be formed on the surface of the core, so that the effect of providing the contact layer by the aerosol deposition method is appropriately exerted.

[0083] In addition, as a method for providing the contact layer, methods such as sputtering and evaporation can be used in addition to the aerosol deposition method.

[0084] So far, the structure related to the anode of the electrolytic capacitor has been described, but next, with reference to Figure 4 the structure related to the cathode of the electrolytic capacitor and other structures constituting the electrolytic capacitor will be described.

[0085] The capacitor element 20 includes a solid electrolyte layer 7a formed on the dielectric layer 5 and a conductive layer 7b formed on the solid electrolyte layer 7a. An electrolytic capacitor provided with a solid electrolyte layer as a part of the cathode can be said to be a solid electrolytic capacitor.

[0086] The end portion on the cathode side of the valve action metal substrate 4 constituting the capacitor element 20 is subjected to insulation treatment such as being covered with the dielectric layer 5, so that the core 4a of the valve action metal substrate 4 does not directly contact the solid electrolyte layer 7a or the conductive layer 7b.

[0087] As materials constituting the solid electrolyte layer, for example, conductive polymers having skeletons such as pyrrole-based, thiophene-based, and aniline-based are cited. As a conductive polymer having a thiophene-based skeleton, for example, PEDOT [poly(3,4-ethylenedioxythiophene)] is cited, and it may also be PEDOT:PSS complexed with polystyrene sulfonic acid (PSS) as a dopant.

[0088] For example, a method of forming a polymer film such as poly(3,4-ethylenedioxythiophene) on the surface of the dielectric layer by using a treatment liquid containing monomers such as 3,4-ethylenedioxythiophene, a method of coating a dispersion liquid of a polymer such as poly(3,4-ethylenedioxythiophene) on the surface of the dielectric layer and drying it, etc. are used to form the solid electrolyte layer. It should be noted that it is preferable to form the solid electrolyte layer for the inner layer that fills the fine pores (recesses) first, and then form the solid electrolyte layer for the outer layer that covers the entire dielectric layer.

[0089] The above-mentioned treatment liquid or dispersion liquid is applied onto the dielectric layer by means of sponge transfer printing, screen printing, spraying, dispenser, inkjet printing, etc., whereby a solid electrolyte layer can be formed in a specified area. The thickness of the solid electrolyte layer is preferably 2 μm or more and preferably 20 μm or less.

[0090] The conductive layer is preferably, for example, 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. Alternatively, it may be a composite layer having a silver layer provided on the carbon layer or the graphene layer, or a mixed layer in which the carbon paste or the graphene paste is mixed with the silver paste.

[0091] A conductive paste such as a carbon paste is formed onto the solid electrolyte layer by means of sponge transfer printing, screen printing, spraying, dispenser, inkjet printing, etc., whereby a conductive layer can be formed.

[0092] Figure 4 The carbon layer 7b1 and the metal layer 7b2 which are the conductive layer 7b are shown.

[0093] The electrolytic capacitor of the present utility model preferably further includes a second conductive resin portion provided on the second surface of the laminate and connected to the conductive layer of the capacitor element, and a second lead frame connected to the second conductive resin portion.

[0094] In Figure 4 In the electrolytic capacitor 1 shown, a second conductive resin portion 23 is formed on the second surface 30b of the laminate 30, and the second conductive resin portion 23 is connected to the conductive layer 7b of the capacitor element 20. Since the second conductive resin portion 23 connected to the conductive layer 7b of the capacitor element 20 is formed integrally, the cathodes of the plurality of capacitor elements 20 are collected in the second conductive resin portion 23. The second surface 30b of the laminate 30 is the cathode-side end face of the laminate.

[0095] The second conductive resin portion 23 is also connected to the second lead frame 13. Since the second conductive resin portion 23 is connected to the conductive layer 7b of the capacitor element 20 and the second lead frame 13, the second lead frame 13 is connected to the conductive layer 7b of the capacitor element 20 via the second conductive resin portion 23.

[0096] The connection between the second lead frame and the conductive layer of the capacitor element can also be made by directly bonding the second lead frame to the conductive layer of the capacitor element without passing through the second conductive resin portion. However, in the case of directly bonding the second lead frame to the conductive layer of the capacitor element, sometimes the bonding area is insufficient, resulting in a high resistance between the second lead frame and the conductive layer of the capacitor element. On the other hand, when the connection between the second lead frame and the conductive layer of the capacitor element is made through the connection via the second conductive resin portion, the second conductive resin portion can enter the gap between the capacitor elements. Therefore, the connection area between the second conductive resin portion and the conductive layer of the capacitor element becomes larger. In addition, the connection area between the second conductive resin portion and the second lead frame also becomes larger. Therefore, the resistance between the second lead frame and the conductive layer of the capacitor element can be reduced. And, the connection via the second conductive resin portion is a resin-based connection, so it is a joining method in which the joined portion is softer than soldering. Therefore, it is possible to prevent the occurrence of defective conditions caused by the separation of the joint between the second lead frame and the conductive layer due to the stress generated by the thermal expansion of each member during reflow soldering.

[0097] As the second lead frame, a lead frame having the same material and shape as those exemplified for the first lead frame can be used. The material and shape of the second lead frame and the first lead frame may be the same or different.

[0098] As the second conductive resin portion, a conductive resin electrode layer including a conductive component and a resin component, which is exemplified as the first conductive resin portion, can be used. The material and shape of the second conductive resin portion and the first conductive resin portion may be the same or different.

[0099] In addition, the contact layer may not be provided on the second surface of the laminate. This is because, even if the contact layer is not provided, in most cases, the connectivity between the conductive layer and the second conductive resin portion can be sufficiently ensured.

[0100] It should be noted that the method of leading out the cathode from the capacitor element in the electrolytic capacitor of the present invention is not limited to the method using the second conductive resin portion and the second lead frame, and other conventionally known leading-out methods can also be used. For example, the following methods can be cited: after leading out the metal foil as the conductive layer to the end face of the resin molded body, a cathode external electrode composed of a resin electrode layer and a plating layer is formed.

[0101] Preferably, a first conductive resin portion and a first lead frame are provided on the first surface of the laminate in which a plurality of capacitor elements are laminated, and a second conductive resin portion and a second lead frame are provided on the second surface of the laminate as needed, and then the periphery thereof is sealed with a sealing resin to form a rectangular parallelepiped resin molded body as a whole.

[0102] The sealing resin constituting the resin molded body includes at least resin, and preferably includes resin and a filler. As the resin, for example, insulating resins such as epoxy resin, phenolic resin, polyimide resin, silicone resin, polyamide resin, and liquid crystal polymer are preferably used. The form of the sealing resin can be either a solid resin or a liquid resin. In addition, as the filler, for example, inorganic particles such as silica particles, alumina particles, and metal particles are preferably used. It is more preferable to use a material including silica particles for solid epoxy resin and phenolic resin.

[0103] As a method for molding the resin molded body, in the case of using a solid sealing material, resin molding such as compression molding and transfer molding is preferably used, and compression molding is more preferably used. In addition, in the case of using a liquid sealing material, molding methods such as dispensing and printing are preferably used.

[0104] The electrolytic capacitor thus obtained preferably has an L shape in the cross-section (LT plane cross-section) obtained by cutting the electrolytic capacitor along the length direction and the thickness direction, where the first lead frame has the first end face (anode side end face) of the electrolytic capacitor as the long side.

[0105] The short side of the L shape becomes the bottom surface of the electrolytic capacitor. The bottom surface of the electrolytic capacitor becomes the mounting surface when mounting the electrolytic capacitor on a substrate or the like. It is preferable that the length of the short side of the L shape is long enough so that the area of the first lead frame on the bottom surface of the electrolytic capacitor is wide enough for mounting.

[0106] In addition, preferably, in the cross-section (LT cross-section) obtained by cutting the electrolytic capacitor along the length direction and the thickness direction, the second lead frame has an L shape with the second end face (cathode side end face) of the electrolytic capacitor as the long side.

[0107] Figure 4 An LT plane cross-sectional view of the electrolytic capacitor is shown. Figure 4 It is shown that the first lead frame 11 and the second lead frame 13 respectively have an L shape in the LT cross-section of the electrolytic capacitor.

[0108] The part of the short side of the L shape of the first lead frame 11 is depicted in Figure 4 as being in contact with the first conductive resin portion 21, the mask layer 40, and the sealing resin 8. It is also possible that the sealing resin 8 enters between the mask layer 40 and the first lead frame 11, and the first lead frame 11 is bonded to the mask layer 40 via the sealing resin 8.

[0109] Note that in Figure 4 the first lead frame 11 is an inverted L shape with the short side facing left, but this shape is also included in the L shape.

[0110] Next, an example of the manufacturing method of the electrolytic capacitor will be described.

[0111] Figure 6 and Figure 7 and Figure 8A and Figure 8B and Figure 9A and Figure 9B and Figure 9C are process diagrams schematically showing a part of the manufacturing process of an electrolytic capacitor.

[0112] Figure 6 Shows a lead frame group used in the manufacture of three electrolytic capacitors. The first lead frame group 110 is on the right and the second lead frame group 120 is on the left.

[0113] A plate-like portion 111 that becomes the first lead frame of the electrolytic capacitor and a connecting portion 112 that connects the plate-like portions 111 are provided in the first lead frame group 110. There are three plate-like portions 111, and a conductive paste 113 that becomes the first conductive resin portion is applied to each plate-like portion 111.

[0114] A plate-like portion 121 that becomes the second lead frame of the electrolytic capacitor and a connecting portion 122 that connects the plate-like portions 121 are provided in the second lead frame group 120. There are three plate-like portions 121, and a conductive paste 123 that becomes the second conductive resin portion is applied to each plate-like portion 121.

[0115] Figure 7 Shows a state in which the laminate 30 is placed on the first lead frame group 110 and the second lead frame group 120.

[0116] The laminate 30 is placed between the plate-like portion 111 that becomes the first lead frame and the plate-like portion 121 that becomes the second lead frame.

[0117] Preferably, a contact layer in direct contact with the core portion is provided on the first surface 30a of the laminate 30. The illustration of the contact layer is omitted.

[0118] Figure 8A Shows a state in which the plate-like portion 111 of the first lead frame group 110 and the plate-like portion 121 of the second lead frame group 120 are bent toward the first surface 30a and the second surface 30b of the laminate 30, respectively. Figure 8B is a side view when observing Figure 8A from the side of the laminate 30.

[0119] Since the conductive paste is applied to each plate-like portion, the end face of the laminate is connected to the plate-like portion by means of the conductive paste.

[0120] The plate-like portion 111 of the first lead frame group 110 becomes the first lead frame 11, and the conductive paste 113 becomes the first conductive resin portion 21.

[0121] The plate-like portion 121 of the second lead frame group 120 becomes the second lead frame 13, and the conductive paste 123 becomes the second conductive resin portion 23.

[0122] Figure 9A The state where the periphery of the laminate 30 is sealed by the sealing resin 8 to form a resin molded body 9 is shown. Figure 9B It is when observing from the side of the resin molded body 9 Figure 9A The side view of the state, Figure 9C It is when observing from the first end face side of the resin molded body 9 Figure 9A The end view of the state.

[0123] Figure 9B The laminate 30 inside the sealing resin 8 is simply shown by a dotted line.

[0124] As Figure 9C shown, the first lead frame 11 is exposed on the first end face of the resin molded body 9.

[0125] Through the processes so far, the electrolytic capacitor is in a state of being connected by the connecting portion of the lead frame group. Therefore, the electrolytic capacitor can be obtained by cutting the connecting portion to make it into single pieces.

[0126] (Another Embodiment of the Electrolytic Capacitor)

[0127] Figure 10 It is the LT plane cross-sectional view of the electrolytic capacitor according to another embodiment.

[0128] In Figure 10 the electrolytic capacitor 201 shown, the mask layer 240 of the capacitor element 220 located on the bottommost side among the capacitor elements 20 constituting the laminate 30 becomes thick.

[0129] In addition, near the second face 30b of the laminate 30, a cathode side spacer 250 is provided under (on the bottom side) the capacitor element 220 located on the bottommost side.

[0130] The cathode side spacer 250 is preferably made of an insulating resin material.

[0131] By providing the mask layer 240 and the cathode side spacer 250 under (on the bottom side) the capacitor element 220 located on the bottommost side, the distance between the capacitor element 220 located on the bottommost side and the bottom face 1c of the electrolytic capacitor 201 becomes longer. In this way, it is prevented that the first lead frame 11 on the bottom face 1c of the electrolytic capacitor 201 contacts the conductive layer 7b of the capacitor element 220 located on the bottommost side and causes a short circuit.

[0132] In addition, by adopting a structure for preventing short circuits in this way, it is possible to increase the length of the short side of the L-shaped first lead frame 11, and make the area of the first lead frame 11 on the bottom surface 1c of the electrolytic capacitor 201 wide enough for installation. At the same time, the conductive layer 7b of the capacitor element 20 can be arranged as close as possible to the position of the first surface 30a of the laminate 30. Therefore, the capacitance of the electrolytic capacitor can be increased.

[0133] The cathode-side spacer 250 is provided to match the height on the anode side.

[0134] Figure 11 It is a cross-sectional view of the LT surface of the electrolytic capacitor according to another embodiment.

[0135] In Figure 11 In the electrolytic capacitor 202 shown, for the capacitor element 220 located on the bottom surface side among the capacitor elements 20 constituting the laminate 30, a cathode-side spacer 250 is provided near the second surface 30b of the laminate 30, and an anode-side spacer 260 is provided near the first surface 30a of the laminate 30.

[0136] The cathode-side spacer 250 and the anode-side spacer 260 are preferably made of an insulating resin material.

[0137] Similar to Figure 10 In the electrolytic capacitor 201 shown, by providing a cathode-side spacer 250 and an anode-side spacer 260 under (on the bottom surface side) the capacitor element 220 located on the bottom surface side, contact between the first lead frame 11 and the conductive layer 7b of the capacitor element 220 located on the bottom surface side is prevented, thereby preventing short circuits. Other effects are the same.

[0138] In Figure 11 In the case of the electrolytic capacitor 202 shown, as the capacitor element 220 located on the bottom surface side, the same specifications (the same specifications of the mask layer) as those of the other capacitor elements 20 can be used. Therefore, there is an advantage over the Figure 10 electrolytic capacitor 201 shown in that it is not necessary to prepare a capacitor element with a thick mask layer.

[0139] Figure 12 It schematically shows Figure 11 a process chart showing a part of the manufacturing process of the electrolytic capacitor shown.

[0140] Figure 12 It shows a lead frame group used in the manufacture of three electrolytic capacitors. On the right is the first lead frame group 110, and on the left is the second lead frame group 120. The lead frame group is the same as the Figure 6 lead frame group shown.

[0141] The spacer paste 270 is applied to the positions of the laminate in the connection portions 112 of the first lead frame group 110 and the connection portions 122 of the second lead frame group 120. By placing the bottom surface of the laminate at the positions where the spacer paste 270 is applied, the cathode-side spacer 250 and the anode-side spacer 260 can be provided.

[0142] After the laminate is placed, an electrolytic capacitor can be manufactured in the same manner as the above-described process.

[0143] In addition, when manufacturing Figure 10 the electrolytic capacitor 201 shown, the cathode-side spacer 250 can be provided by applying the spacer paste 270 only to the connection portions 122 of the second lead frame group 120 in advance.

[0144] It should be noted that the composition of the spacer paste is preferably a composition containing an insulating and adhesive resin material.

[0145] Description of Reference Numerals

[0146] 1 electrolytic capacitor;

[0147] 1a first end face of the electrolytic capacitor;

[0148] 1b second end face of the electrolytic capacitor;

[0149] 1c bottom surface of the electrolytic capacitor;

[0150] 1d upper surface of the electrolytic capacitor;

[0151] 1e first side face of the electrolytic capacitor;

[0152] 1f second side face of the electrolytic capacitor;

[0153] 4 valve-acting metal substrate;

[0154] 4a core part;

[0155] 4b porous part;

[0156] 5 dielectric layer;

[0157] 7a solid electrolyte layer;

[0158] 7b conductive layer;

[0159] 7b1 carbon layer;

[0160] 7b2 metal layer;

[0161] 8 sealing resin;

[0162] 9 resin molded body;

[0163] 11 first lead frame;

[0164] 13 Second lead frame;

[0165] 20 Capacitor element;

[0166] 21 First conductive resin part;

[0167] 23 Second conductive resin part;

[0168] 30 Stacked body;

[0169] 30a First surface of the stacked body;

[0170] 30b Second surface of the stacked body;

[0171] 31 Contact layer;

[0172] 40 Mask layer;

[0173] 110 First lead frame group;

[0174] 111 Plate-like part;

[0175] 112 Connecting part;

[0176] 113 Conductive paste;

[0177] 120 Second lead frame group;

[0178] 121 Plate-like part;

[0179] 122 Connecting part;

[0180] 123 Conductive paste;

[0181] 201, 202 Electrolytic capacitors;

[0182] 220 Capacitor element closest to the bottom surface side;

[0183] 240 Mask layer of the capacitor element closest to the bottom surface side;

[0184] 250 Cathode side spacer;

[0185] 260 Anode side spacer;

[0186] 270 Spacer paste.

Claims

1. An electrolytic capacitor, characterized in that: The electrolytic capacitor includes: A laminate in which a plurality of capacitor elements are laminated and which has a first surface. The capacitor element includes a valve-acting metal substrate having a core portion and a porous portion formed along the surface of the core portion, a dielectric layer formed on the porous portion, a solid electrolyte layer formed on the dielectric layer, and a conductive layer formed on the solid electrolyte layer; A first conductive resin portion provided on the first surface of the laminate and connected to the core portion of the capacitor element; And A first lead frame connected to the core portion via the first conductive resin portion.

2. The electrolytic capacitor according to claim 1, characterized in that: On the first surface of the laminate, a contact layer in direct contact with the core portion is provided, and the core portion is connected to the first conductive resin portion via the contact layer.

3. The electrolytic capacitor according to claim 2, characterized in that: The contact layer is an electrode layer containing at least one selected from the group consisting of Cu, Ni, Sn, Ag, Zn, and Au.

4. The electrolytic capacitor according to claim 2, characterized in that: The contact layer is an electrode layer made of Cu.

5. The electrolytic capacitor according to any one of claims 2 to 4, characterized in that: The thickness of the contact layer formed at the portion of the core portion is thicker than the thickness of the contact layer formed at the portion of the porous portion.

6. The electrolytic capacitor according to any one of claims 1 to 4, characterized in that: The first conductive resin portions connected to the respective core portions of the plurality of capacitor elements are formed integrally.

7. The electrolytic capacitor according to any one of claims 1 to 4, characterized in that: In a cross-section obtained by cutting the electrolytic capacitor in its length direction and thickness direction, the first lead frame has an L shape with the first end face of the electrolytic capacitor being the long side.

8. The electrolytic capacitor according to any one of claims 1 to 4, characterized in that: The periphery of the laminate is sealed with a sealing resin, and a resin molded body in the shape of a rectangular parallelepiped having the surface of the sealing resin and the surface of the first lead frame as the outer surfaces.

9. The electrolytic capacitor according to any one of claims 1 to 4, characterized in that: The electrolytic capacitor further includes: A second conductive resin portion provided on the second surface of the laminate and connected to the conductive layer of the capacitor element; and A second lead frame connected to the second conductive resin portion.

10. The electrolytic capacitor according to claim 9, characterized in that: The periphery of the laminate is sealed with a sealing resin, and a resin molded body in the shape of a rectangular parallelepiped having the surface of the sealing resin, the surface of the first lead frame, and the surface of the second lead frame as the outer surfaces.

Images