Method for manufacturing solid electrolytic capacitor element

Abstract

A method of manufacturing a solid electrolytic capacitor element (30) includes: a step of supplying a cathode paste to a pair of rollers; a step of conveying a collection (10) of solid electrolytic capacitor elements each having an element portion (11) with a pair of main surfaces (11a, 11b), a pair of side surfaces (11c, 11d), and an end surface (11e) between the pair of rollers to which the cathode paste is supplied; and a step of transferring the cathode paste on the pair of rollers to the pair of main surfaces (11a, 11b) and connecting the cathode paste transferred to the pair of main surfaces (11a, 11b) on the pair of side surfaces (11c, 11d) and the end surface (11e).

Description

Technical Field

[0001] This invention relates to a method for manufacturing solid electrolytic capacitor elements. Background Technology

[0002] Patent Document 1 discloses a method for manufacturing a solid electrolytic capacitor, comprising: a step of providing an anode lead-out portion and a cathode forming portion of a capacitor element on both sides of a valve action metal foil having a dielectric oxide coating formed, and covering the cathode forming portion with an insulating coating in a grid pattern; a step of forming a solid electrolyte layer on the cathode forming portion; a step of drilling through holes in at least a portion of the outer periphery of the cathode forming portion, and then forming the cross-section of the cathode forming portion within the through holes; a step of forming a cathode conductive layer on the solid electrolyte and the cross-section of the through holes; and a step of separating the capacitor element according to each grid to produce a product. The method for manufacturing a solid electrolytic capacitor is characterized in that, in the step of forming the cathode conductive layer, a conductive paste is transferred and printed to form the cathode conductive layer.

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-268681 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] In Patent Document 1, the conductive paste is also applied to the cathode forming portion on both sides of the capacitor element and the through hole section provided on the outer periphery of the cathode forming portion. Therefore, the cathode conductive layer formed on both sides of the capacitor element can conduct electricity without generating an interface of conductive coating film.

[0008] Patent Document 1 describes a three-terminal solid electrolytic capacitor. This type of capacitor has anode leads at both ends of the capacitor element and a cathode forming portion between the two anode leads. Through holes located on the outer periphery of the cathode forming portion are formed only on two sides of the cathode forming portion. However, as in Patent Document 1… Figure 5 As recorded, in three-terminal solid electrolytic capacitors, the volume of the capacitor element's capacitance-generating portion is small, making it impossible to develop high capacitance.

[0009] On the other hand, two-terminal solid electrolytic capacitors have an anode lead at one end and a cathode lead at the other end of the capacitor element. Compared to three-terminal solid electrolytic capacitors, the capacitance-generating portion of the capacitor element in a solid electrolytic capacitor is larger, allowing for higher capacitance. However, in two-terminal solid electrolytic capacitors, the cathode forming portion has two sides and one end face, making it difficult to apply the manufacturing method of the three-terminal solid electrolytic capacitor described in Patent Document 1. For example, when a through-hole is formed as described in Patent Document 1, although conductive paste is applied to the two sides of the cathode forming portion, the through-hole is not formed in the region of the cathode forming portion that becomes an end face, and conductive paste is not applied there. Therefore, it is necessary to further cut off the outer periphery of the cathode forming portion to form the end face of the cathode forming portion, and then form a chemically deposited film, a solid electrolyte layer, and a conductive paste layer on this end face, making the manufacturing process complicated.

[0010] The present invention was made to solve the above-mentioned problems, and its object is to provide a method for manufacturing a solid electrolytic capacitor element, which can form the cathode of a solid electrolytic capacitor element for a two-terminal type solid electrolytic capacitor in a simple process.

[0011] Technical solutions for solving the problem

[0012] The method for manufacturing a solid electrolytic capacitor element of the present invention includes: a step of supplying cathode paste to a pair of rollers; a step of conveying an assembly of solid electrolytic capacitor elements having an element portion having a pair of main surfaces, a pair of side surfaces, and an end surface to the pair of rollers on which the cathode paste has been supplied; and a step of transferring the cathode paste on the pair of rollers to the pair of main surfaces and connecting the cathode paste transferred to the pair of main surfaces to the pair of side surfaces and the end surface.

[0013] Invention Effects

[0014] According to the present invention, a method for manufacturing a solid electrolytic capacitor element is provided, which can form the cathode of a solid electrolytic capacitor element for a two-terminal type solid electrolytic capacitor in a simple process. Attached Figure Description

[0015] Figure 1 This is a top view schematically showing an example (elongated structure type) of an assembly of solid electrolytic capacitor elements used in a method for manufacturing solid electrolytic capacitor elements according to an embodiment of the present invention.

[0016] Figure 2 This is a top view schematically illustrating an example of a process for masking the formation of an assembly of solid electrolytic capacitor elements.

[0017] Figure 3 This is a top view schematically illustrating an example of a process for performing a mask treatment (polarization treatment) on the element portion of an assembly of solid electrolytic capacitor elements.

[0018] Figure 4 This is a top view schematically illustrating an example of a process for forming a solid electrolyte layer in the element portion of an assembly of solid electrolytic capacitor elements.

[0019] Figure 5 yes Figure 4 The shown component section is a cross-sectional view along line XX.

[0020] Figure 6 It is Figure 5 The polarization section of the component shown is an enlarged cross-sectional view.

[0021] Figure 7 This is a top view schematically illustrating another example (double-opening configuration) of an assembly of solid electrolytic capacitor elements used in a method for manufacturing solid electrolytic capacitor elements according to an embodiment of the present invention.

[0022] Figure 8 This is a top view schematically showing another example (strip structure type) of an assembly of solid electrolytic capacitor elements used in a method for manufacturing solid electrolytic capacitor elements according to an embodiment of the present invention.

[0023] Figure 9 This is a top view schematically showing another example (double-opening configuration) of an assembly of solid electrolytic capacitor elements used in a method for manufacturing solid electrolytic capacitor elements according to an embodiment of the present invention.

[0024] Figure 10 This is a top view schematically illustrating an example of a process for forming a carbon layer in the element portion of an assembly of solid electrolytic capacitor elements.

[0025] Figure 11 This is a top view schematically illustrating an example of a process for forming a silver layer on the element portion of an assembly of solid electrolytic capacitor elements.

[0026] Figure 12 This is a schematic diagram of an example of a roller transfer printing device for printing cathode paste.

[0027] Figure 13 This is a schematic diagram of another example of a roller transfer printing device used for printing cathode paste.

[0028] Figure 14 This is a perspective view schematically showing the appearance of one side of the component portion of an assembly of solid electrolytic capacitor components with cathode paste transferred onto it.

[0029] Figure 15 This is a perspective view schematically showing the appearance of the other side of the component portion of an assembly of solid electrolytic capacitor components with cathode paste transferred by roller.

[0030] Figure 16 This is a schematic cross-sectional view illustrating an example of a solid electrolytic capacitor element manufactured by a method for manufacturing a solid electrolytic capacitor element according to an embodiment of the present invention, corresponding to... Figure 5 The sectional view shown.

[0031] Figure 17 yes Figure 16 The solid electrolytic capacitor element shown is a cross-sectional view along the YY line.

[0032] Figure 18 This is a schematic cross-sectional view illustrating an example of a solid electrolytic capacitor. Detailed Implementation

[0033] The manufacturing method of solid electrolytic capacitor elements will be described below.

[0034] However, the present invention is not limited to the following structures, and can be appropriately modified and applied without changing the spirit of the invention. Furthermore, combining two or more of the preferred structures described below also constitutes the present invention.

[0035] The attached diagrams are schematic diagrams, and their dimensions, aspect ratios, and scales may sometimes differ from the actual product.

[0036] In this specification, terms indicating relationships between elements (e.g., “parallel,” “perpendicular,” “orthogonal,” etc.) and terms indicating the shape of elements do not necessarily imply a strict manner as described in the text, but also imply a range of substantially equivalent terms, such as a range that includes a degree of difference of a few percent.

[0037] The method for manufacturing a solid electrolytic capacitor element according to an embodiment of the present invention includes: a step of supplying cathode paste to a pair of rollers; a step of conveying an assembly of solid electrolytic capacitor elements having an element portion having a pair of main surfaces, a pair of side surfaces, and an end surface to the pair of rollers on which the cathode paste has been supplied; and a step of transferring the cathode paste on the pair of rollers to the pair of main surfaces and connecting the cathode paste transferred to the pair of main surfaces to the pair of side surfaces and the end surface.

[0038] In this manner, an assembly of solid electrolytic capacitor elements, comprising a pair of main surfaces, a pair of side surfaces, and an end surface, is prepared and conveyed between a pair of rollers supplied with cathode paste. The cathode paste on the rollers is transferred onto the pair of main surfaces of the element portion, and the cathode paste transferred onto the pair of main surfaces is then bonded to the pair of side surfaces and the end surface of the element portion. This allows conductive paste to be supplied simultaneously to the pair of side surfaces and the end surface of the element portion in addition to the pair of main surfaces in the cathode forming section. Therefore, the cathode of a solid electrolytic capacitor element for a two-terminal type solid electrolytic capacitor can be formed in a simple process. Furthermore, a cathode paste layer can be integrally formed on both main surfaces, both side surfaces, and one end surface of the element portion in the cathode forming section. That is, the cathode paste layers supplied to each surface can be formed seamlessly (without interruption) without creating interfaces at their boundaries. As a result, the ESR (equivalent series resistance) of the solid electrolytic capacitor element can be reduced. Furthermore, the cathode forming part of the solid electrolytic capacitor element is sealed continuously within the cathode, thus improving the moisture resistance and other properties of the solid electrolytic capacitor element.

[0039] Hereinafter, the manufacturing method of the solid electrolytic capacitor element according to the embodiments of the present invention will be described in more detail with the aid of the accompanying drawings.

[0040] Figure 1 This is a top view schematically showing an example (elongated structure type) of an assembly of solid electrolytic capacitor elements used in a method for manufacturing solid electrolytic capacitor elements according to an embodiment of the present invention. Figure 2 This is a top view schematically illustrating an example of a process for masking the formation of an assembly of solid electrolytic capacitor elements. Figure 3 This is a top view schematically illustrating an example of a process for performing a mask treatment (polarization treatment) on the element portion of an assembly of solid electrolytic capacitor elements. Figure 4 This is a top view schematically illustrating an example of a process for forming a solid electrolyte layer in the element portion of an assembly of solid electrolytic capacitor elements. Figure 5 yes Figure 4 The shown component section is a cross-sectional view along line XX. Figure 6 It is Figure 5 The polarization section of the component shown is an enlarged cross-sectional view.

[0041] go through Figures 1-4 The process shown prepares an assembly 10 of solid electrolytic capacitor elements having multiple element sections 11. Each element section 11 has a pair of main surfaces 11a and 11b, a pair of side surfaces 11c and 11d, and an end surface 11e.

[0042] Each component part 11 is a flat plate that appears rectangular when viewed from above, such as... Figure 5as well as Figure 6 As shown, it includes an anode foil 31 with a porous valve-acting metal substrate on its surface, and a dielectric layer 33 disposed on the surface of the anode foil 31 (see reference). Figure 6 ,exist Figure 5 (Not shown in the diagram) Two insulating mask materials 35 and 37, which are annular (extending in a strip-like) insulating members disposed around the anode foil 31 with a dielectric layer 33 between them, and a solid electrolyte layer 39 disposed on the anode foil 31 with a dielectric layer 33 between it and the end face 11e of the insulating mask material 37. In each element section 11, the solid electrolyte layer 39 is opposite to the anode foil 31 with a dielectric layer 33 between it and the element section 11.

[0043] In addition, such as Figure 4 As shown, the assembly 10 of solid electrolytic capacitor elements includes a strip-shaped holding portion 13 that connects multiple element portions 11 at fixed intervals.

[0044] The following is about Figures 1-4 The process shown is explained below.

[0045] First, such as Figure 1 As shown, the anode foil 31 is cut into the shape of a solid electrolytic capacitor element (preferably rectangular) by laser processing or punching, and then welded, for example, to a conveying substrate 15 that serves as a holding part 13 to form an assembly 10 of solid electrolytic capacitor elements.

[0046] In this manner, the assembly 10 of solid electrolytic capacitor elements includes a transport substrate 15 containing a metal or resin material, which is disposed parallel to the transport direction of the assembly 10 during the transfer process of the cathode paste described later. The element portion 11 is disposed only on one side of the transport substrate 15. The side surfaces 11c and 11d of the element portion 11 extend in a direction orthogonal to the transport direction (holding portion 13), and the end face 11e of the element portion 11 extends parallel to the transport direction (holding portion 13).

[0047] The anode foil 31, which forms the component part 11, is made of a valve-acting metal substrate with a porous surface. For example... Figure 6 As shown, the anode foil 31 is a thin film (foil) with a rectangular shape in plan view, having a metal substrate portion 31a and a porous portion 31b on the metal substrate portion 31a. A dielectric layer 33 is provided on the surface of the porous portion 31b.

[0048] In addition, in this specification, "top view" means viewing from the normal direction of the main surface of the anode foil.

[0049] The valve-acting metal matrix is ​​composed of elemental metals such as aluminum, tantalum, niobium, titanium, zirconium, or alloys containing these metals.

[0050] In addition, regarding the valve-acting metal substrate, it is sufficient to consist of a core and a porous part provided on at least one main surface of the core. Valve-acting metal substrates with the surface of the metal foil etched or valve-acting metal substrates with porous micro-powder sintered bodies formed on the surface of the metal foil can be appropriately used.

[0051] Figure 7 This is a top view schematically illustrating another example (double-opening configuration) of an assembly of solid electrolytic capacitor elements used in a method for manufacturing solid electrolytic capacitor elements according to an embodiment of the present invention.

[0052] The assembly 10 of solid electrolytic capacitor elements is not particularly limited to Figure 1 The elongated structural type shown is as follows: Figure 7 As shown, it can also be a double-opening structure (fishbone structure). In this case, the element part 11 is provided on both sides of the conveying substrate 15.

[0053] For example, aluminum or stainless steel can be used as the metal material for the conveying substrate 15. For example, fluoropolymer resin, phenolic resin, or glass-epoxy resin composite material can be used as the resin material for the conveying substrate 15.

[0054] In summary, unlike the anode foil 31, the conveying substrate 15 is a highly rigid component, which can also prevent the assembly 10 of solid electrolytic capacitor elements from shaking during the cathode paste transfer process described later.

[0055] Figure 8 This is a top view schematically showing another example (strip structure type) of an assembly of solid electrolytic capacitor elements used in a method for manufacturing solid electrolytic capacitor elements according to an embodiment of the present invention. Figure 9 This is a top view schematically showing another example (double-opening configuration) of an assembly of solid electrolytic capacitor elements used in a method for manufacturing solid electrolytic capacitor elements according to an embodiment of the present invention.

[0056] The assembly 10 of solid electrolytic capacitor elements may also be absent. Figure 1 as well as Figure 7 The conveying substrate 15 shown is as follows: Figure 8 as well as Figure 9 As shown, a frame portion 17, arranged parallel to the conveying direction of the conveying assembly 10 in the cathode paste transfer process described later, can also be provided as a holding portion 13. In this case, the element portion 11 contains the same material as the frame portion 17. Specifically, both are made of the same valve-operated metal substrate and are formed by cutting the same anode foil. The element portion 11 can be as follows: Figure 8 As shown, it is only set on one side of the skeleton part 17 (elongated structure type), or it can be like... Figure 9As shown, it is set on both sides of the skeleton part 17 (double-opening structure (fishbone structure) type).

[0057] Next, as Figure 2 As shown, insulating mask material 35 is applied to the component section 11 for masking treatment for formation.

[0058] Regarding the insulating mask material 35, it can be formed, for example, by applying a mask material containing an insulating resin composition through methods such as screen printing, roller transfer printing, dispensing, or inkjet printing. Examples of insulating resins include, for instance, polyphenylene sulfone (PPS), polyether sulfone (PES), cyanate ester resins, fluoropolymers (tetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, etc.), compositions composed of soluble polyimide siloxanes and epoxy resins, polyimide resins, polyamide-imide resins, and their derivatives or precursors.

[0059] In addition, when using the skeleton part 17 instead of the substrate 15, the skeleton part 17 is formed as a whole, and the anode and cathode are polarized separately, so the mask treatment for the formation is not required.

[0060] Next, the assembly 10 of solid electrolytic capacitor elements undergoes a formation process (anodizing). This forms an oxide film, which becomes the dielectric layer, on the surface of the valve-acting metal substrate. For example, the dielectric layer is composed of aluminum oxide. At this time, an oxide film is also formed on a pair of side surfaces 11c and 11d and an end face 11e of the element portion 11, which has been cut by laser processing or punching.

[0061] Alternatively, a chemically formed foil with an aluminum oxide already formed can be used as the valve action metal substrate. In this case, by performing a chemical forming process on the cut valve action metal substrate, an oxide film is also formed on a pair of side surfaces 11c and 11d and an end face 11e of the cut element portion 11.

[0062] Next, as Figure 3 As shown, insulating mask material 37 is applied to the element part 11 to perform a mask treatment (polarization treatment) for polarization of the anode and cathode parts.

[0063] Regarding the insulating mask material 37, it can be formed, for example, by applying a mask material containing an insulating resin composition through methods such as screen printing, roller printing, dispensing, or inkjet printing. Examples of insulating resins include, for instance, polyphenylene sulfone (PPS), polyether sulfone (PES), cyanate ester resins, fluoropolymers (tetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, etc.), compositions composed of soluble polyimide siloxanes and epoxy resins, polyimide resins, polyamide-imide resins, and their derivatives or precursors.

[0064] Next, as Figure 4 As shown, a solid electrolyte layer 39 is formed on the dielectric layer of the element portion 11. Specifically, the element portion 11 is immersed in a processing solution containing a solid electrolyte, thereby allowing the processing solution to penetrate into the porous portion of the valve-acting metal substrate. After a given immersion time, the element portion 11 is removed from the processing solution and dried at a given temperature and for a given time. The solid electrolyte layer 39 is formed by repeating the immersion, removal, and drying process a given number of times. Alternatively, the formation of the solid electrolyte layer 39 can also be performed by repeating the following operation a given number of times: immersing the element portion 11 in a processing solution containing a precursor of the solid electrolyte (a monomer that becomes a solid electrolyte through oxidative polymerization), and then immersing it in a processing solution containing an oxidant that causes the precursor of the solid electrolyte to undergo oxidative polymerization.

[0065] Furthermore, the method for forming the solid electrolyte layer 39 (the coating method of the treatment solution containing the solid electrolyte or the coating method of the treatment solution containing the precursor of the solid electrolyte) is not particularly limited to the above-described impregnation method. For example, it may also be a coating or roller transfer method using a dispenser or the like. In addition, these methods may be combined.

[0066] The solid electrolyte layer 39 is formed integrally on the element portion 11 on the side closer to the end face 11e than the insulating mask material 37. For example... Figures 4-6 As shown, the solid electrolyte layer 39 can also be connected to the insulating mask material 37.

[0067] A solid electrolyte layer 39 is disposed on the dielectric layer 33. For example... Figure 6 As shown, the solid electrolyte layer 39 is preferably configured to fill a plurality of pores (recesses) in the porous portion 31b of the anode foil 31. However, as long as a portion of the outer surface of the dielectric layer 33 is covered by the solid electrolyte layer 39, there may also be pores (recesses) in the porous portion 31b of the anode foil 31 that are not filled by the solid electrolyte layer 39.

[0068] As a processing liquid containing a solid electrolyte, dispersions of conductive polymers such as polypyrroles, polythiophenes, and polyanilines can be used. Among these, polythiophenes are preferred, and poly(3,4-ethylenedioxythiophene) known as PEDOT is particularly preferred. Furthermore, the aforementioned conductive polymers may also contain dopants such as polystyrene sulfonic acid (PSS). By attaching the dispersion of the conductive polymer to the outer surface of the dielectric layer and drying it, a conductive polymer film can be formed. Alternatively, as a processing liquid containing a precursor of a solid electrolyte, a liquid containing polymeric monomers such as 3,4-ethylenedioxythiophene can also be used. Dopants such as polystyrene sulfonic acid may also be included in the polymeric monomer. Furthermore, an oxidizing agent may be included in the processing liquid containing the precursor of the solid electrolyte. This processing liquid can be attached to the outer surface of the dielectric layer and a conductive polymer film can be formed by oxidative polymerization (chemical polymerization). This conductive polymer film becomes the solid electrolyte layer 39.

[0069] Figure 10 This is a top view schematically illustrating an example of a process for forming a carbon layer in the element portion of an assembly of solid electrolytic capacitor elements.

[0070] Next, carbon paste, used as cathode paste, is transferred to each element section 11 of the assembly 10 of solid electrolytic capacitor elements using a roller transfer printing method, such as... Figure 10 As shown, a carbon layer 41 is formed in each component part 11.

[0071] The carbon layer 41 is formed integrally on the element portion 11 on the side closer to the end face 11e than the insulating mask material 37. For example... Figure 10 As shown, the carbon layer 41 can completely cover the solid electrolyte layer 39, or it can be connected to the insulating mask material 37.

[0072] Furthermore, the method for forming the carbon layer 41 (the method for applying carbon paste) is not particularly limited to roller transfer printing; for example, it can also be immersion printing, but roller transfer printing is preferred. In addition, the application of carbon paste itself can also be omitted.

[0073] Figure 11 This is a top view schematically illustrating an example of a process for forming a silver layer on the element portion of an assembly of solid electrolytic capacitor elements.

[0074] Next, silver paste, used as cathode paste, is transferred to each element section 11 of the solid electrolytic capacitor element assembly 10 using a roller transfer printing method, such as... Figure 11 As shown, a silver layer 43 is formed in each component part 11.

[0075] The silver layer 43 is formed on the component portion 11 on the side closer to the end face 11e than the insulating mask material 37.

[0076] Furthermore, the silver layer 43 is preferably formed as a solid electrolyte layer 39, and the carbon layer 41 is not exposed on the outer surface of the element portion 11. That is, as Figure 11 As shown, the silver layer 43 preferably completely covers the carbon layer 41. In the absence of a carbon layer 41, the silver layer 43 preferably completely covers the solid electrolyte layer 39. This further improves the moisture resistance reliability of the solid electrolytic capacitor element. Furthermore, the silver layer 43 is preferably in contact with the insulating mask material 37.

[0077] Here, use Figure 12 The roller transfer printing device for cathode paste and the roller transfer printing process for cathode paste are further explained.

[0078] Figure 12 This is a schematic diagram of an example of a roller transfer printing device for printing cathode paste.

[0079] Figure 12 The roller transfer printing apparatus 200 shown includes an unwinding section 210, a vertically conveying roller transfer printing section 220A, a temporary drying section 230, a drying section 240, and a winding section 250. An assembly 10 of solid electrolytic capacitor elements, unwound from the unwinding section 210, is conveyed in the order of roller transfer printing section 220A, temporary drying section 230, and drying section 240, and then wound in the winding section 250. The assembly 10 is conveyed in each section at a given conveying speed.

[0080] The unwinding section 210 unwinds the assembly 10 of solid electrolytic capacitor elements, which is wound in a cylindrical shape on the unwinding reel. The roller transfer section 220A transfers cathode paste onto the element portion 11 of the assembly 10 while conveying the assembly 10 supplied from the unwinding section 210. The temporary drying section 230 temporarily dries the transferred cathode paste by conveying the assembly 10 with the cathode paste transferred to the element portion 11. The drying section 240 heats and dries the temporarily dried cathode paste while conveying the assembly 10. The winding section 250 winds the dried cathode paste assembly 10 into a cylindrical shape onto a winding reel.

[0081] The roller transfer section 220A has multiple conveying rollers 221 for conveying the assembly 10 of the solid electrolytic capacitor elements, a pair of rollers (transfer rollers) 222 for conveying the element parts 11 of the assembly 10 therebetween, and a distributor 223 and a scraper 224 provided on each roller 222.

[0082] A pair of rollers 222 are disposed on both sides of the assembly 10 of solid electrolytic capacitor elements conveyed by the conveying rollers 221. Each roller 222 has a circumferential surface made of metal or rubber, on which grooves for supplying cathode paste are formed. The depth of the grooves can be appropriately set considering the desired coating thickness of the cathode paste. Alternatively, grooves may not be formed on the circumferential surface of each roller 222, or the circumferential surface may be smooth. Furthermore, each circumferential surface of the pair of rollers 222 comes into contact with the two main surfaces 11a and 11b of the element portion 11 of the assembly 10. Through this contact, the cathode paste on the circumferential surfaces of the pair of rollers 222 is transferred onto the two main surfaces 11a and 11b of the element portion 11 of the assembly 10.

[0083] Each distributor 223 supplies an appropriate amount of cathode paste to the corresponding roller 222, preventing the cathode paste from dripping off the circumferential surface of the roller 222. Therefore, the consumption of cathode paste can be set to the required minimum.

[0084] Each scraper 224 is positioned a given distance apart from the circumferential surface of its corresponding roller 222, and the amount of cathode paste adhering to the circumferential surface of the corresponding roller 222 is adjusted to an appropriate level by scraping it off. Alternatively, for example, if the cathode paste has a low viscosity, scraping based on the scraper 224 may not be necessary.

[0085] use Figure 12 The roller transfer device 200 shown first... Figure 4 The solid electrolyte layer 39 of the component section 11 of the assembly 10 shown is transferred with carbon paste, and then the carbon paste is dried to form a carbon layer 41 (see reference). Figure 10 ).

[0086] Similarly, using Figure 12 The roller transfer device 200 shown is directed to... Figure 10 The carbon layer 41 of the component part 11 of the assembly 10 shown is transferred with silver paste, and then the silver paste is dried to form a silver layer 43 (see reference). Figure 11 ).

[0087] More specifically, firstly, cathode paste is supplied to a pair of rollers 222 of the roller transfer device 200. At this time, while rotating each roller 222 along the conveying direction of the assembly 10 of solid electrolytic capacitor elements, cathode paste is supplied to each roller 222 from each distributor 223, and the amount of cathode paste is adjusted by each scraper 224.

[0088] Carbon paste is a conductive paste containing carbon particles as conductive components and resin components such as epoxy resin and phenolic resin.

[0089] The viscosity and thixotropic properties of the carbon paste are set considering factors such as the shear speed of roller transfer printing. Furthermore, since it is used in roller transfer printing, a high-boiling-point solvent is preferred as the organic solvent. By using a high-boiling-point solvent, it is possible to achieve delayed drying and prevent drying at the circumferential surface of the roller.

[0090] Silver paste is a conductive paste containing silver particles as a conductive component and resin components such as epoxy resin and phenolic resin. Silver paste may also contain thermoplastic resin as a resin component.

[0091] The viscosity and thixotropic properties of the silver paste are set considering factors such as the shear speed of roller transfer printing. A silver paste that exhibits lower viscosity at high shear speeds (20–250 lm / s) and higher viscosity at low shear speeds (0.01–0.5 lm / s) is preferred. Furthermore, similar to carbon paste, since it is used in roller transfer printing, a high-boiling-point solvent is preferred as the organic solvent. By using a high-boiling-point solvent, it can be made to have delayed drying properties, thus preventing drying at the circumferential surface of the roller.

[0092] Next, an assembly 10 of solid electrolytic capacitor elements, including element portions 11 with a solid electrolyte layer 39, is conveyed between a pair of rollers 222 on which cathode paste has been supplied. At this time, the assembly 10 is conveyed in the extending direction of the holding portion 13 such that only the element portions 11 are sandwiched between the rollers 222, thereby continuously printing cathode paste onto multiple element portions 11. Between the rollers 222, only the region of the element portion 11 on the side closer to the end face 11e than the insulating mask material 37, where a carbon layer 41 (or solid electrolyte layer 39 if no carbon layer 41 is formed) is conveyed.

[0093] The conveying speed of the assembly 10 is, for example, 20 to 150 mm / s. The rotational speed (rpm) of each roller 222 can be calculated based on the conveying speed and the roller diameter. The gap (mm) between a pair of rollers 222 is set taking into account the thickness of the element part 11 (the thickness after the solid electrolyte layer is formed), but it is set to be at least larger than the thickness of the anode foil.

[0094] In addition, the thickness of the anode foil can be 100 μm or more and 150 μm or less, but preferably 110 μm or more and 130 μm or less.

[0095] Furthermore, the thickness of the element portion 11 (the thickness after the solid electrolyte layer is formed) may be 110 μm or more and 180 μm or less, but it is preferably 120 μm or more and 160 μm or less.

[0096] The assembly 10 of solid electrolytic capacitor elements can also be as follows Figure 12The material is conveyed in a direction orthogonal to the horizontal direction, and between a pair of rollers 222. This makes it easier to ensure that the thickness of the cathode paste on the two main surfaces 11a and 11b of the element section 11 is uniform. This is because it is easier to ensure that the amount of cathode paste supplied to the pair of rollers 222 is uniform.

[0097] Figure 13 This is a schematic diagram of another example of a roller transfer printing device used for printing cathode paste.

[0098] like Figure 13 As shown, the roller transfer device 200 can also replace the vertical conveying roller transfer section 220A with a horizontal conveying roller transfer section 220B. Like the vertical conveying roller transfer section 220A, the horizontal conveying roller transfer section 220B has multiple conveying rollers 221 for conveying the assembly 10, a pair of rollers (transfer rollers) 222 for conveying the element portions 11 of the assembly 10, and distributors 223 and scrapers 224 provided on each roller 222 along the conveying path formed by the assembly 10 of solid electrolytic capacitor elements.

[0099] However, in the horizontal conveying roller transfer section 220B, the assembly 10 of solid electrolytic capacitor elements is conveyed horizontally and between a pair of rollers 222. This method is suitable for cases where the conveying substrate 15 is used as the holding part 13. This is because the conveying substrate 15 is hard, making it difficult to bend its conveying direction to a vertical direction. Furthermore, in the case of horizontal conveying, if the rigidity of the holding part 13 is low, the assembly 10 may wobble, but if the conveying substrate 15 is highly rigid, the assembly 10 can be prevented from wobble even during horizontal conveying.

[0100] Figure 14 This is a perspective view schematically showing the appearance of one side of the component portion of an assembly of solid electrolytic capacitor components with cathode paste transferred onto it. Figure 15 This is a perspective view schematically showing the appearance of the other side of the component portion of an assembly of solid electrolytic capacitor components with cathode paste transferred by roller.

[0101] Then, the cathode paste on a pair of rollers 222 is transferred to a pair of main surfaces 11a and 11b of the element section 11, and the cathode paste transferred to the pair of main surfaces 11a and 11b is connected to a pair of side surfaces 11c and 11d and an end surface 11e. More specifically, the cathode paste overflowing from between each roller 222 and each main surface 11a, 11b wraps around the two main surfaces 11a and 11b to the side surfaces 11c and 11d and the end surface 11e and contacts them, thereby connecting the cathode paste to the side surfaces 11c and 11d and the end surface 11e. Therefore, as Figure 14 as well as Figure 15As shown, the cathode paste layer 50 on the two main surfaces 11a and 11b, the two side surfaces 11c and 11d, and the end face 11e becomes seamlessly (uninterruptedly) connected without creating an interface at their boundaries.

[0102] Figure 16 This is a schematic cross-sectional view illustrating an example of a solid electrolytic capacitor element manufactured by a method for manufacturing a solid electrolytic capacitor element according to an embodiment of the present invention, corresponding to... Figure 5 The sectional view shown. Figure 17 yes Figure 16 The solid electrolytic capacitor element shown is a cross-sectional view along the YY line.

[0103] The above results are as follows: Figure 16 as well as Figure 17 As shown, solid electrolytic capacitor elements 30 are formed in each element section 11. Furthermore, the silver layers 43 in each surface of the solid electrolytic capacitor element 30 are seamlessly (uninterruptedly) connected without creating interfaces at their boundaries.

[0104] Furthermore, in each element section 11, the solid electrolyte layer 39, carbon layer 41, and silver layer 43 (solid electrolyte layer 39 and silver layer 43 if carbon layer 41 is not formed) on the side closer to the end face 11e of the insulating mask material 37 function as cathodes, while the anode foil 31 on the opposite side functions as an anode. Therefore, a two-terminal solid electrolytic capacitor can be manufactured simply by using each element section 11.

[0105] For example, multiple component sections 11 are stacked, and the anode and cathode are respectively connected to the lead frame to form a stack.

[0106] The stacked and adjacent element portions 11 can also be bonded to each other with a conductive adhesive, but it is preferable to integrate them by remelting the resin component contained in the silver layer 43 of each element portion 11. In the latter case, a thermoplastic resin is preferably used as the resin component contained in the silver layer 43.

[0107] The laminate is then sealed, and the lead frame is shaped and cut to form the external terminals. The result is the fabrication of a two-terminal solid electrolytic capacitor.

[0108] Figure 18 This is a schematic cross-sectional view illustrating an example of a solid electrolytic capacitor.

[0109] Figure 18 The solid electrolytic capacitor 100 shown is a two-terminal solid electrolytic capacitor with the following structure: the lead frame 101 is located at the bottom, and solid electrolytic capacitor elements 30 are stacked on the lead frame 101 in sequence.

[0110] In addition, Figure 18 Only the characteristic parts of the structure of a solid electrolytic capacitor are shown. Details such as the bonding between the anode and the outside, and the resin sealing are omitted, but these are the methods that can be used in conventional solid electrolytic capacitors.

[0111] Furthermore, the lead frame 101 may not be positioned at the bottom layer and can be sandwiched between the cathodes of two solid electrolytic capacitor elements 30. Therefore, it is also possible to stack multiple solid electrolytic capacitor elements 30 by stacking the cathodes of multiple solid electrolytic capacitor elements 30, place the lead frame 101 on the stack, and then stack other solid electrolytic capacitor elements 30 cathodes on the lead frame 101 to create other stacks of multiple solid electrolytic capacitor elements 30, thereby creating a stack in which the lead frame 101 is sandwiched between the cathodes, and then heating and pressurizing it.

[0112] The following information is disclosed in this specification.

[0113] <1>

[0114] A method for manufacturing a solid electrolytic capacitor element, comprising:

[0115] The process of supplying cathode paste to a pair of rollers;

[0116] The process of conveying an assembly of solid electrolytic capacitor elements, each having a pair of main surfaces, a pair of side surfaces, and end surfaces, between a pair of rollers to which the cathode paste is supplied; and

[0117] The process of transferring the cathode paste on the pair of rollers to the pair of main surfaces and attaching the cathode paste transferred to the pair of main surfaces to the pair of side surfaces and the end surfaces.

[0118] <2>

[0119] According to the manufacturing method of the solid electrolytic capacitor element described in <1>, wherein,

[0120] The cathode paste is at least one of a treatment solution containing a solid electrolyte, a treatment solution containing a precursor of a solid electrolyte, carbon paste, and silver paste.

[0121] <3>

[0122] According to the manufacturing method of the solid electrolytic capacitor element described in <1> or <2>, wherein,

[0123] The assembly of the solid electrolytic capacitor elements has a conveying substrate containing metal or resin material arranged parallel to the conveying direction.

[0124] The component is disposed on one or both sides of the conveying substrate.

[0125] <4>

[0126] According to the manufacturing method of the solid electrolytic capacitor element described in <1> or <2>, wherein,

[0127] The assembly of the solid electrolytic capacitor elements has a frame portion arranged parallel to the conveying direction.

[0128] The component portion comprises the same material as the skeleton portion and is disposed on one or both sides of the skeleton portion.

[0129] <5>

[0130] The method for manufacturing a solid electrolytic capacitor element according to any one of <1> to <4>, wherein,

[0131] The assembly of the solid electrolytic capacitor elements is conveyed horizontally and fed between the pair of rollers.

[0132] <6>

[0133] The method for manufacturing a solid electrolytic capacitor element according to any one of <1> to <4>, wherein,

[0134] The assembly of solid electrolytic capacitor elements is conveyed in a direction orthogonal to the horizontal direction and supplied between the pair of rollers.

[0135] Explanation of reference numerals in the attached figures

[0136] 10: An assembly of solid electrolytic capacitor elements;

[0137] 11: Components Section;

[0138] 11a, 11b: Main surfaces of the component section;

[0139] 11c, 11d: Side views of the component section;

[0140] 11e: End face of the component section;

[0141] 13: Maintaining section;

[0142] 15: Transporting substrate;

[0143] 17: Skeletal part;

[0144] 30: Solid electrolytic capacitor elements;

[0145] 31: Anode foil;

[0146] 31a: Metal matrix portion;

[0147] 31b: Porous portion;

[0148] 33: Dielectric layer;

[0149] 35, 37: Insulating mask material;

[0150] 39: Solid electrolyte layer;

[0151] 41: Carbon layer;

[0152] 43: Silver layer;

[0153] 50: Cathode paste layer;

[0154] 100: Solid electrolytic capacitor;

[0155] 101: Lead frame;

[0156] 200: Roller transfer printing device;

[0157] 210: Open Book Section;

[0158] 220A: Vertical conveyance roller transfer section;

[0159] 220B: Horizontal conveyor roller transfer printing section;

[0160] 221: Conveying roller;

[0161] 222: Roller (transfer roller);

[0162] 223: Distributor;

[0163] 224: Scraper;

[0164] 230: Temporary drying section;

[0165] 240: Drying section;

[0166] 250: Winding section.

Claims

1. A method for manufacturing a solid electrolytic capacitor element, comprising: The process of supplying cathode paste to a pair of rollers; The process of conveying an assembly of solid electrolytic capacitor elements, each having a pair of main surfaces, a pair of side surfaces, and end surfaces, between a pair of rollers to which the cathode paste is supplied; and The process of transferring the cathode paste on the pair of rollers to the pair of main surfaces and attaching the cathode paste transferred to the pair of main surfaces to the pair of side surfaces and the end surfaces.

2. The method for manufacturing a solid electrolytic capacitor element according to claim 1, wherein, The cathode paste is at least one of a treatment solution containing a solid electrolyte, a treatment solution containing a precursor of a solid electrolyte, carbon paste, and silver paste.

3. The method for manufacturing a solid electrolytic capacitor element according to claim 1 or 2, wherein, The assembly of the solid electrolytic capacitor elements has a conveying substrate containing metal or resin material arranged parallel to the conveying direction. The component is disposed on one or both sides of the conveying substrate.

4. The method for manufacturing a solid electrolytic capacitor element according to claim 1 or 2, wherein, The assembly of the solid electrolytic capacitor elements has a frame portion arranged parallel to the conveying direction. The component portion comprises the same material as the skeleton portion and is disposed on one or both sides of the skeleton portion.

5. A method for manufacturing a solid electrolytic capacitor element according to any one of claims 1 to 4, wherein, The assembly of the solid electrolytic capacitor elements is conveyed horizontally and fed between the pair of rollers.

6. A method for manufacturing a solid electrolytic capacitor element according to any one of claims 1 to 4, wherein, The assembly of solid electrolytic capacitor elements is conveyed in a direction orthogonal to the horizontal direction and fed between the pair of rollers.

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