Solid electrolytic capacitor and method for manufacturing solid electrolytic capacitor

Abstract

To provide a solid electrolytic capacitor excellent in productivity, and a method for manufacturing the solid electrolytic capacitor, with which an area ratio of a capacitor element portion in an anode foil and a mechanical strength of the anode foil can be improved.SOLUTION: A solid electrolytic capacitor 100 includes: a laminate 11 in which a plurality of solid electrolytic capacitor elements 10 are laminated; a sealing body 110 sealing the laminate; and an anode terminal electrode 120 and a cathode terminal electrode 130 provided on the same surface of the sealing body. Each of the solid electrolytic capacitor elements includes an anode foil 40 and a cathode portion 43 provided in a central part 40C of the anode foil so as not to cover one end 40A and an other end 40B of the anode foil. The one ends 40A of the anode foils of the solid electrolytic capacitor elements are electrically connected to each other and connected to the anode terminal electrode, while the other ends 40B are sealed with the sealing body. A plurality of the cathode portions of the solid electrolytic capacitor elements are electrically connected to each other, and are electrically connected to the cathode terminal electrode.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a solid electrolytic capacitor and a method for manufacturing a solid electrolytic capacitor. [Background technology]

[0002] In Patent Document 1, holes are made continuously at predetermined intervals in the longitudinal direction of a continuous strip-shaped anode foil made of a valve metal, and insulating tape is then applied to cover the holes from the front and back sides, thereby separating the end sides in the width direction into cathode lead parts and the central side into an anode lead part. Slits are then provided at predetermined intervals in the end parts that will become the cathode lead parts to form a plurality of continuous protrusions. An anode conversion coating that serves as a dielectric is then formed on the surface of the anode foil. A conductive material is then uniformly attached in islands or layers on the anode conversion coating of the cathode lead parts, and a conductive tape is then applied on the insulating tape. Electrolytic polymerization is then performed using the conductive tape as a polymerization initiation point. The method for producing a solid electrolytic capacitor includes the steps of: forming a conductive polymer film on the cathode lead portion via the conductive layer by bonding the conductive tape to the cathode lead portion; subsequently, peeling off the conductive tape and cutting the strip-shaped anode foil into individual pieces to produce individual plate-shaped capacitor elements; stacking a plurality of these plate-shaped capacitor elements at predetermined positions of terminals provided at regular intervals on a strip-shaped metal lead frame and electrically connecting the elements to the terminals; subsequently, assembling the plurality of capacitor elements by integrally covering them with an exterior resin so that a portion of the terminals is exposed to the outside; and cutting the resulting pieces into individual pieces and separating them from the metal lead frame to obtain individual products. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-243663 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, slits are provided on both sides of a strip-shaped anode foil along its longitudinal direction, forming multiple protrusions (element parts) on both sides. Then, to separate the multiple protrusions on both sides from the central part of the anode foil, insulating tape is applied to both sides, and then conductive tape is applied on top of that. Here, the central part of the anode foil functions to transport the strip-shaped anode foil, and also functions as a polymerized electrode due to the applied conductive tape.

[0005] However, the central part of the strip-shaped anode foil is only a part of the anode foil, and considering the area ratio of the element part to the area of ​​the entire anode foil, the area ratio of the element part is significantly reduced by the central part of the anode foil, resulting in reduced productivity. Therefore, it is necessary to reduce the area of ​​the central part as much as possible (reducing the width), but the above-mentioned transport function requires mechanical strength that can withstand the rotation and twisting of the anode foil and the tension of the transport rollers when transporting a long length, making it difficult to reduce the area.

[0006] The present invention has been made to solve the above problems, and aims to provide a solid electrolytic capacitor with excellent productivity, and a method for manufacturing a solid electrolytic capacitor that can improve the area ratio of the capacitor element portion in the anode foil and the mechanical strength of the anode foil. [Means for solving the problem]

[0007] The solid electrolytic capacitor of the present invention comprises a laminate in which a plurality of solid electrolytic capacitor elements are stacked, a sealing body that seals the laminate, and an anode terminal electrode and a cathode terminal electrode provided on the same side of the sealing body, each of the solid electrolytic capacitor elements includes an anode foil and a cathode portion provided in a center of the anode foil so as not to cover one end or the other end of the anode foil, one ends of the anode foils of the plurality of solid electrolytic capacitor elements are electrically connected to each other and to the anode terminal electrode, the other ends of the plurality of anode foils are sealed with the sealing body, and the plurality of cathode portions of the plurality of solid electrolytic capacitor elements are electrically connected to each other and to the cathode terminal electrode.

[0008] A method for manufacturing a solid electrolytic capacitor of the present invention includes the steps of: preparing a long anode foil; forming rectangular through holes in a matrix in the anode foil to form a plurality of capacitor element series extending in the short side direction of the anode foil in the longitudinal direction of the anode foil and forming a plurality of connecting portions connecting adjacent capacitor element series in the longitudinal direction; and forming a cathode portion in a central portion of each capacitor element portion included in each capacitor element series such that the anode foil is exposed at both ends in the short side direction of the capacitor element portion, to form a capacitor element sheet, wherein each capacitor element series includes three or more capacitor element portions lined up in the short side direction, the capacitor element portions are formed in three or more rows along the longitudinal direction, and four or more connecting portions are provided in the short side direction between adjacent capacitor element series in the longitudinal direction, and four or more rows are formed along the longitudinal direction. Effect of the Invention

[0009] According to the present invention, it is possible to provide a solid electrolytic capacitor with excellent productivity, and a method for manufacturing a solid electrolytic capacitor that can improve the area ratio of the capacitor element portion in the anode foil and the mechanical strength of the anode foil. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view illustrating an example of a solid electrolytic capacitor according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line XX of the solid electrolytic capacitor shown in FIG. [Diagram 3] FIG. 3 is a cross-sectional view that illustrates a schematic diagram of an example of a solid electrolytic capacitor element included in the solid electrolytic capacitor illustrated in FIG. [Figure 4] FIG. 4 is an enlarged cross-sectional view of a polarized portion of the solid electrolytic capacitor element shown in FIG. [Diagram 5] FIG. 5 is a cross-sectional view that illustrates a schematic diagram of an example of a solid electrolytic capacitor according to another embodiment of the present invention, and corresponds to the cross-sectional view shown in FIG. [Figure 6] FIG. 6 is a cross-sectional view that illustrates a schematic diagram of an example of a solid electrolytic capacitor according to still another embodiment of the present invention, and corresponds to the cross-sectional view shown in FIG. [Figure 7] FIG. 7 is a plan view that illustrates an example of an anode foil according to an embodiment of the present invention. [Figure 8] FIG. 8 is a plan view that illustrates an example of a step of forming a through hole in an anode foil. [Figure 9] Fig. 9A is a plan view showing a schematic diagram of another example of the through hole, and Fig. 9B is a plan view showing a schematic diagram of yet another example of the through hole. [Figure 10] FIG. 10 is a plan view that illustrates another example of the step of forming through holes in an anode foil. [Figure 11] FIG. 11 is a plan view that illustrates an example of a process for forming a polarizing portion on an anode foil. [Figure 12] FIG. 12 is a plan view that illustrates an example of a step of forming a solid electrolyte layer on an anode foil. [Figure 13] FIG. 13 is a plan view that illustrates an example of a step of forming a carbon layer on an anode foil. [Figure 14] FIG. 14 is a plan view that illustrates an example of a step of forming a cathode conductor layer on an anode foil. [Figure 15] Fig. 15A is a plan view diagrammatically illustrating an example of a process for laminating capacitor element sheets, and Fig. 15B is a side view as viewed from the direction of the arrow in Fig. 15A. [Figure 16] FIG. 16 is a side view that illustrates an example of a step of connecting an anode foil. [Figure 17] FIG. 17 is a side view that illustrates an example of a step of connecting terminal electrodes. [Figure 18] Fig. 18A is a plan view diagrammatically illustrating an example of a step of cutting a laminated capacitor element sheet, and Fig. 18B is a side view as viewed from the direction of the arrow in Fig. 18A. [Figure 19]Fig. 19A is a plan view diagrammatically illustrating an example of a step of sealing the cut capacitor element sheet, and Fig. 19B is a side view as viewed from the direction of the arrow in Fig. 19A. [Figure 20] Fig. 20A is a plan view diagrammatically illustrating an example of a process for dividing the sealing block into individual pieces, and Fig. 20B is a side view as viewed from the direction of the arrow in Fig. 20A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The solid electrolytic capacitor and the method for manufacturing the solid electrolytic capacitor will be described below. However, the present invention is not limited to the following configurations, and can be modified as appropriate within the scope of the present invention. Note that the present invention also includes a combination of two or more of the individual desirable configurations described below.

[0012] [Solid electrolytic capacitor] Fig. 1 is a perspective view showing an example of a solid electrolytic capacitor according to an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along line XX of the solid electrolytic capacitor shown in Fig. 1. In FIG. 2, the dielectric layer 41 of the solid electrolytic capacitor element 10 is omitted.

[0013] 1 and 2, the length direction of solid electrolytic capacitor 100 and sealing body 110 is indicated by L, the width direction by W, and the height direction by T. Here, the length direction L, the width direction W, and the height direction T are perpendicular to each other.

[0014] 1 and 2, solid electrolytic capacitor 100 has a substantially rectangular parallelepiped outer shape. Solid electrolytic capacitor 100 includes laminate 11, sealing body 110, anode terminal electrode 120 which is a first external electrode, and cathode terminal electrode 130 which is a second external electrode.

[0015] The laminate 11 is formed by laminating a plurality of solid electrolytic capacitor elements 10 (hereinafter sometimes simply referred to as "elements 10"). The number of elements 10 included in the laminate 11 is not particularly limited as long as it is two or more, and can be set appropriately.

[0016] The sealing body 110 seals the laminate 11. The sealing body 110 is made of an insulating sealing resin, and is provided around the laminate 11.

[0017] The sealing body 110 has a substantially rectangular parallelepiped outer shape. The sealing body 110 has a first main surface 110a and a second main surface 110b that face each other in a height direction T, a first side surface 110c and a second side surface 110d that face each other in a width direction W, and a first end surface 110e and a second end surface 110f that face each other in a length direction L.

[0018] As described above, the plug 110 has a substantially rectangular parallelepiped outer shape, but the corners and ridges may be rounded. A corner is a portion where three faces of the plug 110 intersect, and a ridge is a portion where two faces of the plug 110 intersect.

[0019] The anode terminal electrode 120 and the cathode terminal electrode 130 are formed on the same surface of the sealing body 110, which is the second main surface 110b in this example.

[0020] The multiple elements 10 are arranged so as to overlap each other in the height direction T. The extending direction of each of the multiple elements 10 is substantially parallel to the first main surface 110a and the second main surface 110b of the sealing body 110.

[0021] Each element 10 is a substantially flat electronic component element, and includes an anode foil 40 and a cathode portion 43. The cathode portion 43 is provided in a central portion 40C of the anode foil 40 so as not to cover one end 40A and the other end 40B of the anode foil 40.

[0022] The anode foils 40 of the elements 10 are electrically connected to one another at their first ends 40A. For example, the anode foils 40 are welded to one another via the spacers 21.

[0023] Moreover, one ends 40A of the multiple anode foils 40 of the multiple elements 10 are electrically connected to the anode terminal electrode 120. For example, one end 40A of the anode foil 40 of the element 10 located closest to the second main surface 110b is welded to the anode terminal electrode 120.

[0024] In contrast, the other ends 40B of the multiple anode foils 40 of the multiple elements 10 are sealed with a sealing body 110. The other ends 40B of the multiple anode foils 40 may or may not be electrically connected to each other. In the former case, for example, the other ends 40B of the multiple anode foils 40 may be welded to each other via a spacer 22 as shown in FIG.

[0025] The cathode portions 43 of the elements 10 are electrically connected to each other. The cathode portions 43 adjacent to each other in the height direction T may simply be in contact with each other, or may be joined to each other via a conductive adhesive (not shown).

[0026] The cathode portions 43 of the elements 10 are electrically connected to the cathode terminal electrode 130. For example, the cathode portion 43 of the element 10 located closest to the second main surface 110b is welded to the cathode terminal electrode 130.

[0027] Such solid electrolytic capacitor 100 can be produced by a method for producing a solid electrolytic capacitor, which will be described later, and therefore has excellent productivity.

[0028] Each component of solid electrolytic capacitor 100 will be further described below.

[0029] Fig. 3 is a cross-sectional view showing a schematic example of a solid electrolytic capacitor element included in the solid electrolytic capacitor shown in Fig. 1. Fig. 4 is an enlarged cross-sectional view of a polarized portion of the solid electrolytic capacitor element shown in Fig. 3.

[0030] 3 and 4, the anode foil 40 is a thin film (foil) having a rectangular shape in a plan view, which has a metal base portion 40a and a porous portion 40b on the metal base portion 40a. A dielectric layer 41 is provided on the surface of the porous portion 40b. The cathode portion 43 is provided on the dielectric layer 41, and in each element 10, the cathode portion 43 faces the anode foil 40 with the dielectric layer 41 interposed therebetween.

[0031] In this specification, the term "planar view" means a view from the normal direction of the main surface of the anode foil.

[0032] The anode foil 40 is a thin film (foil) made of a valve metal and having a four-sided quadrangular shape in plan view, and is preferably a rectangular shape (strip shape) having a pair of long sides and a pair of short sides in plan view. As shown in FIG. 2, the anode foil 40 extends between the first end face 110e and the second end face 110f of the sealing body 110.

[0033] As shown in Fig. 4, the anode foil 40 has a metal base portion 40a and a porous portion 40b in which a plurality of recesses are provided. Therefore, each main surface of the anode foil 40 is porous. This increases the surface area of ​​the anode foil 40. Note that the anode foil 40 is not limited to a case in which both main surfaces are porous (porous portion 40b), and only one of the main surfaces of the anode foil 40 may be porous (porous portion 40b).

[0034] The metal base portion 40a is a core metal portion of the anode foil 40, and the thickness of the metal base portion 40a is approximately constant.

[0035] The anode foil 40 is made of a valve metal, such as an elemental metal such as aluminum, tantalum, niobium, titanium, zirconium, or an alloy containing these metals. An oxide film can be formed on the surface of the valve metal.

[0036] The anode foil 40 may be composed of a metal base portion 40a and a porous portion 40b provided on at least one of the main surfaces of the metal base portion 40a. For example, a metal foil having an etched surface or a metal foil having a porous sintered powder formed on the surface thereof may be used.

[0037] Here, the dielectric layer 41 is provided on the surface of the porous portion 40b of the anode foil 40 (see FIG. 4). That is, the dielectric layer 41 is provided on the entire anode foil 40 except for both end faces in the longitudinal direction L of the anode foil 40, as shown in FIG. However, it is sufficient that the dielectric layer 41 is provided on at least one of the two main surfaces of the anode foil 40 excluding at least both end surfaces.

[0038] The dielectric layer 41 is preferably made of an oxide film provided on the surface of the porous portion 40b of the anode foil 40. For example, the dielectric layer 41 is made of an aluminum oxide. The aluminum oxide is formed by anodizing the surface of a valve metal base, as described later.

[0039] 3, the cathode section 43 has a solid electrolyte layer 44 provided on the dielectric layer 41, and a conductive layer 45 provided on the solid electrolyte layer 44. Also, as shown in Fig. 4 and Fig. 3, the cathode section 43 is provided on the dielectric layer 41 in a region sandwiched between polarizing sections 31 described later.

[0040] The solid electrolyte layer 44 is provided on the dielectric layer 41. As shown in Fig. 4, the solid electrolyte layer 44 is preferably provided so as to fill a plurality of pores (recesses) of the porous portion 40b of the anode foil 40. However, it is sufficient that part of the outer surface of the dielectric layer 41 is covered with the solid electrolyte layer 44, and there may be pores (recesses) of the porous portion 40b of the anode foil 40 that are not filled with the solid electrolyte layer 44.

[0041] The solid electrolyte layer 44 is provided on the dielectric layer 41 in a region sandwiched by the polarizing portions 31. Here, the solid electrolyte layer 44 is in contact with the polarizing portions 31, but may be disposed up to the front of the polarizing portions 31.

[0042] 3, the conductive layer 45 is provided on the solid electrolyte layer 44. The conductive layer 45 covers substantially the entire area of ​​the solid electrolyte layer 44. Here, the conductive layer 45 is in contact with the polarizing portion 31, but may be disposed up to just before the polarizing portion 31. The conductive layer 45 has a substantially constant thickness.

[0043] The conductive layer 45 is, for example, a composite layer in which a cathode conductor layer 45b is provided on the outer surface of a carbon layer 45a. The conductive layer 45 may include only one of the carbon layer 45a or the cathode conductor layer 45b, or may be a mixed layer including carbon and a cathode conductor layer material.

[0044] 2 and 3, the polarization portion 31 is an insulating mask layer provided on the dielectric layer 41 along each of one end 40A and the other end 40B (preferably the short side) of the anode foil 40, and separates the anode foil 40 from the cathode portion 43 to ensure insulation between them. The polarization portion 31 is provided linearly (extending in a strip shape) along each of one end 40A and the other end 40B of the anode foil 40.

[0045] Here, each polarizing portion 31 is provided in a tubular shape so as to surround the periphery of the anode foil 40, but it is sufficient that it is provided on at least one of the main surfaces of the anode foil 40 (the main surface on which the dielectric layer 41 is provided).

[0046] 4, the polarizing portion 31 is preferably provided so as to fill a plurality of pores (recesses) in the porous portion 40b of the anode foil 40. However, it is sufficient that the polarizing portion 31 covers a part of the outer surface of the dielectric layer 41, and there may be pores (recesses) in the porous portion 40b that are not filled with the polarizing portion 31.

[0047] 2, the sealing body 110 seals a plurality of elements 10. That is, in the sealing body 110, a stack 11 of the plurality of elements 10 is embedded.

[0048] The sealing body 110 is made of, for example, an insulating sealing resin.

[0049] The sealing resin contains at least a resin, and preferably contains a resin and a filler.

[0050] As the resin, an epoxy resin, a phenol resin, a polyimide resin, a silicone resin, a polyamide resin, a liquid crystal polymer, or the like is preferably used.

[0051] As the filler, silica particles, alumina particles, metal particles, etc. are preferably used.

[0052] As the sealing resin, a material containing a solid epoxy resin, a phenolic resin, and silica particles is preferably used.

[0053] When a solid sealing resin is used, a resin mold such as a compression mold or a transfer mold is preferably used, and a compression mold is more preferably used. When a liquid sealing resin is used, a molding method such as a dispensing method or a printing method is preferably used. Among them, it is preferable to form the sealing body 110 by sealing the periphery of the element 10 with the sealing resin by compression molding.

[0054] 2, each spacer 21 is disposed between one ends 40A of the anode foils 40 adjacent in the height direction T, and is connected (welded) to one ends 40A of the anode foils 40 adjacent in the height direction T. As a result, one ends 40A of the multiple anode foils 40 are electrically connected to one another.

[0055] The ends 40A of the multiple anode foils 40 may be electrically connected to each other, for example, by being directly welded to each other.

[0056] 2, each spacer 22 is disposed between the other ends 40B of the anode foils 40 adjacent in the height direction T, and is connected (welded) to the other ends 40B of the anode foils 40 adjacent in the height direction T. As a result, the other ends 40B of the multiple anode foils 40 are electrically connected to one another.

[0057] The other ends 40B of the multiple anode foils 40 may be electrically connected to each other, for example, by being directly welded to each other. Alternatively, the spacers 22 may not be provided, and the other ends 40B of the multiple anode foils 40 may not be electrically connected to each other, as described above.

[0058] The spacers 21 and 22 may be made of a metal or alloy such as copper, aluminum, or stainless steel.

[0059] 2, anode terminal electrode 120 is provided on second main surface 110b of sealing body 110. Anode terminal electrode 120 is electrically connected to one end 40A of anode foil 40 exposed from sealing body 110 at second main surface 110b. Anode terminal electrode 120 may be connected directly or indirectly to anode foil 40.

[0060] 2, cathode terminal electrode 130 is provided on second main surface 110b of sealing body 110. Cathode terminal electrode 130 is electrically connected to cathode portion 43 exposed from sealing body 110 at second main surface 110b. Cathode terminal electrode 130 may be connected directly or indirectly to cathode portion 43.

[0061] The anode terminal electrode 120 and the cathode terminal electrode 130 are formed, for example, from a thin plate of a metal or an alloy. More specifically, they may be formed from a thin plate having a base material made of copper, a Ni layer formed on the surface of the base material, and a Sn layer formed on the surface of the Ni layer. The Ni layer and the Sn layer can each be formed, for example, by a plating method.

[0062] FIG. 5 is a cross-sectional view that illustrates a schematic diagram of an example of a solid electrolytic capacitor according to another embodiment of the present invention, and corresponds to the cross-sectional view shown in FIG.

[0063] 5 differs from the solid electrolytic capacitor 100 shown in FIG 2 in the following respects. That is, in the solid electrolytic capacitor 100A, on one end 40A side of the anode foil 40, the conductive layer 45 is disposed up to the front of the polarization portion 31. More specifically, on one end 40A side of the anode foil 40, the carbon layer 45a is disposed up to the front of the polarization portion 31, and the cathode conductor layer 45b is disposed up to the front of the end of the carbon layer 45a on the polarization portion 31 side.

[0064] FIG. 6 is a cross-sectional view that illustrates a schematic diagram of an example of a solid electrolytic capacitor according to still another embodiment of the present invention, and corresponds to the cross-sectional view shown in FIG.

[0065] The solid electrolytic capacitor 100B shown in Fig. 6 differs from the solid electrolytic capacitor 100 shown in Fig. 2 in the following respects. That is, in the solid electrolytic capacitor 100B, at one end 40A side and the other end 40B side of the anode foil 40, the conductive layer 45 is disposed up to the front of the polarization portion 31. More specifically, at one end 40A side and the other end 40B side of the anode foil 40, the carbon layer 45a is disposed up to the front of the polarization portion 31, and the cathode conductor layer 45b is disposed up to the front of the end of the carbon layer 45a on the polarization portion 31 side.

[0066] [Solid electrolytic capacitor manufacturing method] The solid electrolytic capacitor 100 can be manufactured by the following method.

[0067] (Anode foil preparation process) FIG. 7 is a plan view that illustrates an example of an anode foil according to an embodiment of the present invention.

[0068] As shown in FIG. 7, first, a long anode foil 210 is prepared. The anode foil 210 is pulled out from a roll of anode foil, and is continuously subjected to the following steps while being transported along its longitudinal direction D1.

[0069] The anode foil 210 is made of a valve metal substrate having a porous portion on the surface of the metal substrate.

[0070] The valve metal substrate is made of a valve metal such as an elemental metal such as aluminum, tantalum, niobium, titanium, or zirconium, or an alloy containing these metals. The valve action metal base need only be composed of a metal base portion and a porous portion provided on at least one of the main surfaces of the metal base portion, and may be, for example, a metal foil having an etched surface or a metal foil having a porous sintered powder body formed on the surface.

[0071] The dimensions of the anode foil 210 in the longitudinal direction D1 and the transverse direction D2 are not particularly limited and can be set appropriately. The dimension of the anode foil 210 in the transverse direction D2 can be set according to the dimension in the length direction L of the solid electrolytic capacitor to be fabricated.

[0072] (Through hole formation process) FIG. 8 is a plan view that illustrates an example of a step of forming a through hole in an anode foil.

[0073] Next, as shown in FIG. 8, rectangular through holes 211 are formed in a matrix in anode foil 210 to form a plurality of capacitor element series 220 and a plurality of connecting portions 230. Each capacitor element series 220 extends in the short-side direction D2 of the anode foil 210, and a plurality of capacitor element series 220 are formed in the longitudinal direction of the anode foil 210. Each connecting portion 230 connects adjacent capacitor element series 220 in the longitudinal direction D1 of the anode foil 210.

[0074] Each capacitor element series 220 includes three or more capacitor element portions 221 arranged in the short direction D2 of the anode foil 210, and the capacitor element portions 221 are formed in three or more rows (four rows in Figure 8) along the longitudinal direction D1 of the anode foil 210, and four or more connecting portions 230 are provided in the short direction D2 between adjacent capacitor element series 220 in the longitudinal direction D1, and four or more rows (five rows in Figure 8) are formed along the longitudinal direction D1. This makes it possible to improve productivity by increasing the area ratio of the capacitor element portion 221 in the anode foil 210. Furthermore, the mechanical strength of the anode foil 210 can be improved while increasing the area ratio.

[0075] 8, in addition to the through holes 211, through holes (transport holes) 212 for transporting the anode foil 210 may be provided at equal intervals along the longitudinal direction D1 of the anode foil 210. In this way, by rotating the gear while inserting the teeth of the gear into the through holes 212, the anode foil 210 can be easily transported in the longitudinal direction D1.

[0076] Each of the through holes 211 and 212 can be formed, for example, by laser processing or punching the anode foil 210. The through holes 211 are preferably rectangular or slit-shaped, and are formed so that their longitudinal direction is parallel to the short-side direction D2 of the anode foil 210. The through holes 211 are provided in three or more rows along the long-side direction D1 of the anode foil 210. The through holes 211 are formed so that three or more are lined up on a straight line parallel to the short-side direction D2 of the anode foil 210.

[0077] In addition, the rectangular shape of the through hole 211 does not necessarily have to be strictly rectangular, but may be a rectangular shape with rounded corners or a rectangular shape with chamfered corners, as long as the macroscopic shape is rectangular.

[0078] Fig. 9A is a plan view showing a schematic diagram of another example of the through hole, and Fig. 9B is a plan view showing a schematic diagram of yet another example of the through hole.

[0079] More specifically, for example, as shown in FIG. 9A, the shape of the through hole 211 itself may be rectangular with rounded or chamfered corners, or as shown in FIG. 9B, the shape of the region that becomes the cathode portion 250 of the capacitor element portion may be rectangular with rounded or chamfered corners.

[0080] The dimensions of each through hole 211 in the longitudinal direction D1 and the lateral direction D2 of the anode foil 210 are not particularly limited and can be set appropriately. As shown in Fig. 8, the dimensions of all the through holes 211 in the longitudinal direction D1 may be the same, and the dimensions of all the through holes 211 in the lateral direction D2 may be the same.

[0081] Each capacitor element series 220 corresponds to an area for forming three or more solid electrolytic capacitor elements. Each capacitor element series 220 is preferably rectangular, and is formed so that its longitudinal direction is parallel to the short-side direction D2 of the anode foil 210.

[0082] Each capacitor element portion 221 corresponds to a region for forming a solid electrolytic capacitor element. Each capacitor element portion 221 is preferably rectangular, and is formed so that its longitudinal direction is parallel to the short-side direction D2 of the anode foil 210.

[0083] The dimensions of each capacitor element portion 221 in the longitudinal direction D1 and the lateral direction D2 of the anode foil 210 can be set appropriately according to the size of the solid electrolytic capacitor element to be fabricated.

[0084] Each connecting portion 230 is preferably rectangular, and four or more through holes 211 are formed lined up on a straight line parallel to the short side direction D2 of the anode foil 210. The connecting portions 230 and the through holes 211 are alternately arranged on the straight line parallel to the short side direction D2 of the anode foil 210, and the connecting portions 230 are located at both ends in the short side direction D2.

[0085] The dimensions of each of the connecting portions 230 in the longitudinal direction D1 and the transverse direction D2 of the anode foil 210 are not particularly limited and can be set appropriately.

[0086] As shown in FIG. 8, it is preferable that dimension A of each connecting portion 230 in the short-side direction D2 of the anode foil 210 is smaller than dimension B of each capacitor element portion 221 in the short-side direction D2 of the anode foil 210.

[0087] FIG. 10 is a plan view that illustrates another example of the step of forming through holes in an anode foil.

[0088] 10 , a dimension C in the short side direction D2 of the connecting portion 230 located at the center in the short side direction D2 of the anode foil 210 may be larger than a dimension A in the short side direction D2 of the other connecting portions 230. By providing a wide connecting portion 230 at the center in the short side direction D2 in this manner, it becomes easier to ensure an area for forming the through hole (transport hole) 212 for transporting the anode foil 210.

[0089] (Polarizing part forming process) FIG. 11 is a plan view that illustrates an example of a process for forming a polarizing portion on an anode foil.

[0090] Next, as shown in FIG. 11, polarized portions 240 of the anode and cathode portions of each capacitor element portion 221 are formed along longitudinal direction D1 of anode foil 210.

[0091] The polarized portions 240 are preferably formed so as to contact the ends (more preferably both ends) of the through-holes 211 in the short-side direction D2 of the anode foil 210. This allows the side surfaces (the surfaces facing the through-holes 211) of each connecting portion 230 to be protected by the polarized portions 240. Also, the area of ​​the cathode portion formed in each capacitor element portion 221 can be increased. In this manner, the polarized portions 240 are preferably formed in six or more linear rows along the longitudinal direction D1 of the anode foil 210.

[0092] The polarizing portion 240 is formed by applying a mask material such as a composition containing an insulating resin by screen printing, roller transfer, dispenser, inkjet printing, etc. Examples of the insulating resin include polyphenylsulfone (PPS), polyethersulfone (PES), cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene-perfluoroalkylvinylether copolymer, etc.), a composition consisting of soluble polyimidesiloxane and epoxy resin, polyimide resin, polyamideimide resin, and derivatives or precursors thereof.

[0093] After this, the polarizing portion 240 may or may not be coated with a hydrophilic material.

[0094] Next, an oxide film serving as a dielectric layer is formed on the surface of the valve metal base by anodizing the valve metal base constituting the anode foil 210. For example, the dielectric layer is made of an aluminum oxide. At this time, an oxide film is also formed on the side surface of the anode foil 210 that has been processed by laser processing, punching, or the like. A chemically-formed foil on which an aluminum oxide has already been formed may be used as the valve metal base. In this case, an oxide film is also formed on the side surface of the processed anode foil 210 by anodizing the processed valve metal base.

[0095] (Cathode part formation process) Fig. 12 is a plan view showing an example of a process for forming a solid electrolyte layer on an anode foil, Fig. 13 is a plan view showing an example of a process for forming a carbon layer on an anode foil, and Fig. 14 is a plan view showing an example of a process for forming a cathode conductor layer on an anode foil.

[0096] 12 to 14, a cathode portion 250 is formed in the center of each capacitor element portion 221 included in each capacitor element string 220 so that the anode foil 210 is exposed at both ends (both ends in the short-side direction D2 of the anode foil 210) of the capacitor element portion 221. Here, a solid electrolyte layer 251 (FIG. 12), a carbon layer 252 (FIG. 13), and a cathode conductor layer 253 (FIG. 14) are laminated in this order.

[0097] Solid electrolyte layer 251 is formed up to the boundary with polarizing section 240 or until it slightly overlaps polarizing section 240. Carbon layer 252 is formed in the same position as solid electrolyte layer 251. Cathode conductor layer 253 is formed in the same position as carbon layer 252.

[0098] At least on one end side of the capacitor element portion 221, the carbon layer 252 may be formed slightly closer to the center than the solid electrolyte layer 251 (see FIGS. 5 and 6). Similarly, at least on one end side of the capacitor element portion 221, the cathode conductor layer 253 may be formed slightly closer to the center than the carbon layer 252 (see FIGS. 5 and 6).

[0099] The solid electrolyte layer 251, the carbon layer 252, and the cathode conductor layer 253 can be formed by, for example, a printing method, a dispensing method, a transfer method, a dipping method, a tape peeling method, etc. In particular, the printing method and the transfer method, which can selectively apply the material to the capacitor element portion 221, are preferred, and the roller transfer method is particularly preferred.

[0100] The solid electrolyte layer 251 can be formed by using a treatment liquid containing a solid electrolyte. The treatment liquid is impregnated into the porous portion of the valve metal substrate, and then the porous portion is dried at a predetermined temperature for a predetermined time, thereby forming the solid electrolyte layer 251.

[0101] As the treatment liquid containing a solid electrolyte, for example, a dispersion liquid of a conductive polymer such as polypyrroles, polythiophenes, polyanilines, etc. is used. Among these, polythiophenes are preferred, and poly(3,4-ethylenedioxythiophene) called PEDOT is particularly preferred. The conductive polymer may also contain a dopant such as polystyrene sulfonic acid (PSS). By attaching the dispersion liquid of the conductive polymer to the outer surface of the dielectric layer and drying it, a conductive polymer film can be formed as the solid electrolyte layer 251. Alternatively, as the treatment liquid containing a solid electrolyte, a liquid containing a polymerizable monomer, for example, a polymerizable monomer such as 3,4-ethylenedioxythiophene, and an oxidizing agent may be used. This containing liquid can be attached to the outer surface of the dielectric layer to form a conductive polymer film by chemical polymerization. This conductive polymer film becomes the solid electrolyte layer 251.

[0102] The carbon layer 252 can be formed using carbon paste. The carbon paste is applied to the surface of the solid electrolyte layer 251 and dried to form the carbon layer 252 in a predetermined region. The carbon paste is a conductive paste that contains carbon particles as a conductive component and a resin component such as an epoxy resin or a phenol resin.

[0103] The cathode conductor layer 253 can be formed using a conductive paste. The conductive paste is applied to the surface of the carbon layer 252 and dried to form the cathode conductor layer 253 in a predetermined region. The conductive paste for forming the cathode conductor layer may contain, for example, metal particles as a conductive component and a resin component such as an epoxy resin or a phenolic resin. The metal particles may be, for example, gold, silver, copper, platinum, or the like. Among them, a silver paste containing silver particles as a conductive component is preferable as the conductive paste for forming the cathode conductor layer.

[0104] Thereafter, the anode foil 210 is cut to a predetermined size in the longitudinal direction D1, thereby producing the capacitor element sheet 201 in which a solid electrolytic capacitor element is formed in each of the capacitor element portions 221.

[0105] (Lamination process) Fig. 15A is a plan view diagrammatically illustrating an example of a process for laminating capacitor element sheets, and Fig. 15B is a side view as viewed from the direction of the arrow in Fig. 15A.

[0106] Next, as shown in FIGS. 15A and 15B, a plurality of capacitor element sheets 201 are laminated so that the cathode portions 250 of the capacitor element portions 221 overlap each other.

[0107] As shown in FIG. 15B, anode foil 210 is exposed at one end and the other end of each capacitor element portion 221.

[0108] The capacitor element sheets 201 may be laminated as they are (see FIGS. 15A and 15B), or may be cut into rows as shown by the dashed lines in the longitudinal direction D1 in FIG. 15A and then laminated.

[0109] Furthermore, the capacitor element sheets 201 may be laminated without any intervening portions (see FIG. 15B), or may be laminated with a conductive adhesive interposed therebetween.

[0110] (Anode foil connection process) FIG. 16 is a side view that illustrates an example of a step of connecting an anode foil.

[0111] Next, as shown in FIG. 16, the anode foil portions 213 exposed at one end and the other end of the stacked capacitor element portions 221 are electrically connected to each other.

[0112] Resistance welding or laser welding is suitable as a method for electrically connecting the anode foil portions 213 to each other. In this case, it is preferable to provide a spacer 260 between adjacent anode foil portions 213 (adjacent anode foil portions 213 in the stacking direction) exposed at one end and the other end of the plurality of capacitor element portions 221, and to weld the plurality of anode foil portions 213 exposed at one end and the other end together with the spacer 260.

[0113] Spacers 260 may be elongated conductive thin plates made of a metal or alloy such as copper, aluminum, stainless steel, etc.

[0114] When the anode foil portion 213 is welded, an anode terminal electrode and a cathode terminal electrode, which will be described later, may be welded at the same time.

[0115] (Terminal electrode connection process) FIG. 17 is a side view that illustrates an example of a step of connecting terminal electrodes.

[0116] Next, as shown in FIG. 17 , an anode terminal electrode 270 is electrically connected to the multiple anode foil portions 213 that are electrically connected to each other, and a cathode terminal electrode 280 is electrically connected to the multiple cathode portions 250 of the multiple stacked capacitor element portions 221. In this way, the anode foil portion 213 is exposed at both ends of each capacitor element portion 221, and only one of them is connected to the anode terminal electrode 270. The cathode terminal electrode 280 is led out from the cathode portion 250 (cathode conductor layer 253) in the center of each capacitor element portion 221.

[0117] In FIG. 17, the cathode terminal electrode 280 is provided in common to two capacitor element portions 221 adjacent to each other in the short-side direction D2 of the anode foil 210, but the cathode terminal electrode 280 may be connected to each of the capacitor element portions 221.

[0118] In addition, in FIG. 17, the anode terminal electrode 270 and the cathode terminal electrode 280 are provided on the lower surface of the laminate of multiple capacitor element portions 221, but the anode terminal electrode 270 and the cathode terminal electrode 280 may be drawn out from the center of the laminate in the stacking direction.

[0119] Also, side electrodes may be formed on the side surfaces of the laminate using conductive paste. However, in this case, since the anode foil parts 213 exposed at both ends of each capacitor element part 221 are welded and the adhesion between the elements is excellent, this side electrode or the conductive adhesive described above may not be necessary.

[0120] (cutting process) Fig. 18A is a plan view diagrammatically illustrating an example of a step of cutting a laminated capacitor element sheet, and Fig. 18B is a side view as viewed from the direction of the arrow in Fig. 18A.

[0121] Next, as indicated by the dashed lines in FIGS. 18A and 18B, the capacitor element sheet 201 is cut along the longitudinal direction D1 of the anode foil 210 for each row of the capacitor element portions 221. As a result, the anode foil portions 213 exposed at both ends of each capacitor element portion 221 are divided into two, and the anode terminal electrode 270, the cathode terminal electrode 280 and the spacer 260 are also divided into two.

[0122] (Sealing process) Fig. 19A is a plan view diagrammatically illustrating an example of a step of sealing the cut capacitor element sheet, and Fig. 19B is a side view as viewed from the direction of the arrow in Fig. 19A.

[0123] Next, as shown in FIGS. 19A and 19B, the laminated capacitor element sheets 201 are sealed with a sealant 203 to form a sealing block 202 so that the anode terminal electrode 270 and the cathode terminal electrode 280 are exposed.

[0124] As the sealing material 203 for sealing the capacitor element sheet 201, for example, the insulating sealing resin described above can be used.

[0125] As the sealing method, the above-mentioned methods, for example, compression molding, can be used.

[0126] (Singulation process) Fig. 20A is a plan view diagrammatically illustrating an example of a process for dividing the sealing block into individual pieces, and Fig. 20B is a side view as viewed from the direction of the arrow in Fig. 20A.

[0127] Next, as shown in FIGS. 20A and 20B, sealing block 202 is cut into individual pieces for each of the stacked capacitor element portions 221.

[0128] As a result of the above, a solid electrolytic capacitor 100 can be obtained in which a plurality of elements 10 are sealed in sealing body 110, as shown in FIG. 20B.

[0129] Thereafter, solid electrolytic capacitor 100 may be barrel polished. Specifically, solid electrolytic capacitor 100 may be sealed together with an abrasive in a barrel tank, and solid electrolytic capacitor 100 may be polished by rotating the barrel tank. This allows corners and ridges of sealant 110 to be rounded.

[0130] The present specification discloses the following:

[0131] <1> a laminate in which a plurality of solid electrolytic capacitor elements are laminated; A sealant that seals the laminate; and an anode terminal electrode and a cathode terminal electrode provided on the same surface of the sealing body, each of the solid electrolytic capacitor elements includes an anode foil and a cathode portion provided in a central portion of the anode foil so as not to cover one end or the other end of the anode foil; one ends of the anode foils of the solid electrolytic capacitor elements are electrically connected to each other and to the anode terminal electrode; the other ends of the plurality of anode foils are sealed with the sealing body, a solid electrolytic capacitor, wherein the cathode portions of the solid electrolytic capacitor elements are electrically connected to each other and to the cathode terminal electrode.

[0132] <2> A step of preparing a long anode foil; forming rectangular through holes in a matrix in the anode foil to form a plurality of capacitor element series extending in a short side direction of the anode foil in a longitudinal direction of the anode foil, and forming a plurality of connecting portions connecting adjacent capacitor element series in the longitudinal direction; forming a cathode portion in a central portion of each capacitor element portion included in each of the capacitor element series such that the anode foil is exposed at both ends in the short side direction of the capacitor element portion, thereby forming a capacitor element sheet; Each of the capacitor element series includes three or more capacitor element portions arranged in the short side direction, The capacitor element portions are formed in three or more rows along the longitudinal direction, The method for manufacturing a solid electrolytic capacitor, wherein four or more connecting portions are provided in the short side direction between adjacent capacitor elements in the longitudinal direction, and four or more rows are formed along the longitudinal direction.

[0133] <3> a dimension of each of the coupling portions in the short side direction is smaller than a dimension of each of the capacitor element portions in the short side direction; <2> 2. A method for producing the solid electrolytic capacitor according to claim 1 .

[0134] <4> A dimension in the short side direction of a connecting portion located at a center in the short side direction is larger than dimensions in the short side direction of other connecting portions. <3> 2. A method for producing the solid electrolytic capacitor according to claim 1 .

[0135] <5> a step of forming a polarized portion of the anode portion and the cathode portion of each of the capacitor element portions along the longitudinal direction before forming the cathode portion. <2> from <4> 13. A method for producing the solid electrolytic capacitor according to claim 12.

[0136] <6> The polarizing portion is formed so as to be in contact with an end portion of the through hole in the short side direction. <5> 2. A method for producing the solid electrolytic capacitor according to claim 1 .

[0137] <7> laminating a plurality of the capacitor element sheets such that the cathode portions of the capacitor element portions overlap each other; and electrically connecting the plurality of anode foil portions exposed at one ends of the plurality of stacked capacitor element portions to each other. <2> from <6> 13. A method for producing the solid electrolytic capacitor according to claim 12.

[0138] <8> The anode foil portions exposed at the one end are resistance-welded or laser-welded. <7> 2. A method for producing the solid electrolytic capacitor according to claim 1 .

[0139] <9> providing a spacer between adjacent anode foil portions exposed at the one end, and welding the plurality of anode foil portions exposed at the one end together with the spacer; <8> 2. A method for producing the solid electrolytic capacitor according to claim 1 .

[0140] <10> the anode foil portions exposed at the other ends of the stacked capacitor element portions are electrically connected to each other. <7> from <9> 13. A method for producing the solid electrolytic capacitor according to claim 12.

[0141] <11> a step of electrically connecting an anode terminal electrode to the plurality of anode foil portions electrically connected to each other, and electrically connecting a cathode terminal electrode to the plurality of cathode portions of the plurality of stacked capacitor element portions, <7> from <10> 13. A method for producing the solid electrolytic capacitor according to claim 12.

[0142] <12> a step of sealing the stacked capacitor element sheets so that the anode terminal electrodes and the cathode terminal electrodes are exposed to form a sealing block; and cutting the sealing block into individual pieces for each of the stacked capacitor element portions. <11> 2. A method for producing the solid electrolytic capacitor according to claim 1 . [Explanation of symbols]

[0143] 10 Solid electrolytic capacitor element 11 Laminate 21, 22, 260 Spacer 31, 240 Polarizing section 40, 210 Anode foil One end of the 40A anode foil 40B The other end of the anode foil 40C Center of anode foil 40a Metal base part 40b Porous part 41 Dielectric layer 43, 250 Cathode 44, 251 solid electrolyte layer 45 Conductive Layer 45a, 252 carbon layer 45b, 253 Cathode conductor layer 100, 100A, 100B Solid Electrolytic Capacitor 110 Sealing body 110a 1st main surface 110b 2nd principal surface 110c 1st side 110d 2nd side 110e 1st end face 110f 2nd end face 120, 270 anode terminal electrode 130, 280 cathode terminal electrode 201 Capacitor element sheet 202 Sealing block 203 Encapsulating materials 211 Through hole 212 Through hole (transport hole) 213 Anode foil section 220 Capacitor element series 221 Capacitor element part 230 Connection section

Claims

1. a laminate in which a plurality of solid electrolytic capacitor elements are laminated; A sealant that seals the laminate; and an anode terminal electrode and a cathode terminal electrode provided on the same surface of the sealing body, each of the solid electrolytic capacitor elements includes an anode foil and a cathode portion provided in a central portion of the anode foil so as not to cover one end or the other end of the anode foil; one ends of the anode foils of the solid electrolytic capacitor elements are electrically connected to each other and to the anode terminal electrode; the other ends of the plurality of anode foils are sealed with the sealing body, a solid electrolytic capacitor, wherein the cathode portions of the solid electrolytic capacitor elements are electrically connected to each other and to the cathode terminal electrode.

2. A step of preparing a long anode foil; forming rectangular through holes in a matrix in the anode foil to form a plurality of capacitor element series extending in a short side direction of the anode foil in a longitudinal direction of the anode foil, and forming a plurality of connecting portions connecting adjacent capacitor element series in the longitudinal direction; forming a cathode portion in a central portion of each capacitor element portion included in each of the capacitor element series such that the anode foil is exposed at both ends in the short side direction of the capacitor element portion, thereby forming a capacitor element sheet; Each of the capacitor element series includes three or more capacitor element portions arranged in the short side direction, The capacitor element portions are formed in three or more rows along the longitudinal direction, The method for manufacturing a solid electrolytic capacitor, wherein four or more connecting portions are provided in the short side direction between adjacent capacitor element series in the longitudinal direction, and four or more rows are formed along the longitudinal direction.

3. The method for manufacturing a solid electrolytic capacitor according to claim 2 , wherein a dimension of each of the connecting portions in the short side direction is smaller than a dimension of each of the capacitor element portions in the short side direction.

4. The method for manufacturing a solid electrolytic capacitor according to claim 3 , wherein a dimension in the short side direction of a connecting portion located at a center in the short side direction is larger than dimensions in the short side direction of other connecting portions.

5. 4. The method for manufacturing a solid electrolytic capacitor according to claim 2, further comprising the step of forming a polarized portion of an anode portion and a polarized portion of a cathode portion of each of the capacitor element portions along the longitudinal direction before forming the cathode portion.

6. The method for manufacturing a solid electrolytic capacitor according to claim 5 , wherein the polarizing portion is formed so as to contact an end portion of the through hole in the short side direction.

7. laminating a plurality of the capacitor element sheets such that the cathode portions of the capacitor element portions overlap each other; 4. The method for producing a solid electrolytic capacitor according to claim 2, further comprising the step of electrically connecting the anode foil portions exposed at one ends of the stacked capacitor element portions to each other.

8. The method for manufacturing a solid electrolytic capacitor according to claim 7 , wherein the anode foil portions exposed at the one end are resistance-welded or laser-welded.

9. 9. The method for manufacturing a solid electrolytic capacitor according to claim 8, further comprising providing a spacer between adjacent anode foil portions exposed at said one end, and welding said anode foil portions exposed at said one end together with said spacer.

10. The method for producing a solid electrolytic capacitor according to claim 7 , further comprising electrically connecting a plurality of anode foil portions exposed at the other ends of the plurality of stacked capacitor element portions to each other.

11. 8. The method for manufacturing a solid electrolytic capacitor according to claim 7, further comprising the step of electrically connecting an anode terminal electrode to the plurality of anode foil portions that are electrically connected to each other, and electrically connecting a cathode terminal electrode to the plurality of cathode portions of the plurality of stacked capacitor element portions.

12. a step of sealing the stacked capacitor element sheets so that the anode terminal electrodes and the cathode terminal electrodes are exposed to form a sealing block; The method for manufacturing a solid electrolytic capacitor according to claim 11 , further comprising the step of cutting the sealing block into individual pieces for each of the plurality of stacked capacitor element portions.

Images