Solid electrolyte capacitor manufacturing method and solid electrolyte capacitor

Abstract

This solid electrolyte capacitor manufacturing method includes a step for forming a plurality of flat-film capacitor elements, an anode through-hole forming step, a cathode through-hole forming step, a sheet laminate forming step, a sealing step, and a singulation step. In the step for forming a plurality of flat-film capacitor elements, a dielectric layer and a solid electrolyte layer are sequentially formed on the surface of a flat-film anode electrode foil. In the anode through-hole forming step, through-holes penetrating through the plurality of flat-film capacitor elements in the thickness direction are formed. In the cathode through-hole forming step, through-holes penetrating through a flat-film cathode electrode foil in the thickness direction are formed. In the sheet laminate forming step, the plurality of flat-film capacitor elements and the flat-film cathode electrode foil are alternately laminated via the solid electrolyte layer. In the sealing step, the sheet laminate is sealed with an insulating resin. In the singulation step, the sheet laminate sealed with the insulating resin is singulated along a first cutting line and a second cutting line orthogonal to the first cutting line. The anode through-holes and the cathode through-holes are formed along the first cutting line and the second cutting line. In the sheet laminate forming step, the laminating is performed such that the anode through-holes and the cathode through-holes overlap each other in the thickness direction.

Description

Method for manufacturing a solid electrolytic capacitor, and a solid electrolytic capacitor

[0001] The present invention relates to a solid electrolytic capacitor having a structure in which a laminate of a plurality of capacitor elements is molded with an insulating resin.

[0002] Patent Document 1 describes a method for manufacturing a solid electrolytic capacitor and a solid electrolytic capacitor. The solid electrolytic capacitor described in Patent Document 1 includes a plurality of flat-film capacitor elements and a plurality of metal foils (cathodes). The flat-film capacitor elements include a foil-shaped valve metal substrate, a porous portion of the valve metal substrate and a dielectric layer formed on the surface thereof, and a solid electrolyte layer formed on the surface of the dielectric layer.

[0003] The flat film capacitor elements and the metal foils are alternately stacked to form an element stack, which is then sealed with an insulating resin.

[0004] Patent Document 2 describes a method for manufacturing a solid electrolytic capacitor. The method for manufacturing a solid electrolytic capacitor described in Patent Document 2 includes a step of forming an element assembly, a step of forming a laminate, and a step of singulating the laminate. In the step of forming the element assembly, capacitor elements having a dielectric layer are arranged in a planar manner. In the step of forming the laminate, multiple element assemblies are stacked. In the singulation step, the multiple laminates are singulated into individual laminates.

[0005] JP 2019-79866 A JP 2020-194825 A

[0006] However, the manufacturing methods of solid electrolytic capacitors as exemplified in Patent Documents 1 and 2 include the following multiple steps: (Step 1) forming an element stack; (Step 2) sealing the element stack with an insulating material such as insulating resin; (Step 3) cutting the sealed element stack (primary dicing step); (Step 4) sealing the element stack cut in step 3 with an insulating material such as insulating resin; and (Step 5) singulating the element stack formed in step 4 (secondary dicing step).

[0007] That is, the manufacturing process of the solid electrolytic capacitor in Patent Documents 1 and 2 includes two sealing steps and two dicing steps, which means that the dicing is inefficient and takes a long processing time.

[0008] Therefore, when a solid electrolytic capacitor is formed using the manufacturing methods of Patent Documents 1 and 2, there is a risk that the manufacturing efficiency will decrease and productivity will also decrease in terms of cost.

[0009] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method for efficiently manufacturing a solid electrolytic capacitor, and the solid electrolytic capacitor.

[0010] A method for manufacturing a solid electrolytic capacitor according to the present invention includes the steps of forming a plurality of flat-film capacitor elements, forming anode through holes, forming cathode through holes, forming a sheet laminate, sealing, and singulating. In the step of forming a plurality of flat-film capacitor elements, a dielectric layer and a solid electrolyte layer are sequentially formed on the surface of a flat-film anode electrode foil. In the step of forming anode through holes, through holes are formed that penetrate the plurality of flat-film capacitor elements in the thickness direction. In the step of forming cathode through holes, through holes are formed that penetrate the flat-film cathode electrode foil in the thickness direction. In the step of forming a sheet laminate, a plurality of flat-film capacitor elements and flat-film cathode electrode foils are alternately stacked with solid electrolyte layers interposed therebetween. In the sealing step, the sheet laminate is sealed with an insulating resin. In the singulating step, the sheet laminate sealed with the insulating resin is singulated along first cutting lines and second cutting lines perpendicular to the first cutting lines.

[0011] The anode through hole and the cathode through hole are formed along the first cutting line and the second cutting line. In the step of forming the sheet laminate, the anode through hole and the cathode through hole are stacked so as to overlap each other in the thickness direction.

[0012] In this manufacturing method, the sheet laminate has anode through holes and cathode through holes formed along the first cutting line and the second cutting line, and these through holes are filled with insulating resin. By dicing this sheet laminate, individual sheet laminates can be formed. That is, the process of filling with insulating resin and the process of singulating can be performed once each to form the desired individual sheet laminates. This makes it possible to efficiently form solid electrolytic capacitors.

[0013] The solid electrolytic capacitor of the present invention comprises a plurality of flat-film capacitor elements, a flat-film cathode electrode foil, an anode through-hole, a cathode through-hole, a sheet laminate, and an insulating resin. The plurality of flat-film capacitor elements have a dielectric layer and a solid electrolyte layer sequentially formed on the surface of a flat-film anode electrode foil. The anode through-hole penetrates the plurality of flat-film capacitor elements in the thickness direction. The cathode through-hole penetrates the flat-film cathode electrode foil in the thickness direction. The sheet laminate is formed by alternately stacking the plurality of flat-film capacitor elements and flat-film cathode electrode foil with the solid electrolyte layer interposed therebetween. The insulating resin seals the sheet laminate.

[0014] The sheet laminate sealed with insulating resin is divided into individual pieces along first cutting lines and second cutting lines perpendicular to the first cutting lines. The anode through holes and cathode through holes are formed along the first cutting lines and the second cutting lines. The anode through holes and cathode through holes are stacked so as to overlap each other in the thickness direction.

[0015] This solid electrolytic capacitor has anode through-holes and cathode through-holes in the sheet laminate, and these through-holes are filled with insulating resin. By dicing this sheet laminate, individual sheet laminates can be formed. That is, the process of filling with insulating resin and the process of dicing can each be performed once to form the desired individual sheet laminates. This allows for an efficiently formed solid electrolytic capacitor.

[0016] According to the present invention, it is possible to provide a method for efficiently manufacturing a solid electrolytic capacitor, and a solid electrolytic capacitor manufactured by this manufacturing method.

[0017] FIG. 1 is a side cross-sectional view showing the configuration of a solid electrolytic capacitor according to the first embodiment. FIGS. 2A and 2B are side cross-sectional views showing the configuration of a set of capacitor elements and cathode electrodes before singulation. FIG. 3 is a flowchart showing an example of a general flow of a method for manufacturing a solid electrolytic capacitor according to the present embodiment. FIG. 4 is an external perspective view showing a state in which capacitor element sheets and cathode electrode sheets are laminated. FIG. 5 is a flowchart showing an example of a capacitor element sheet forming process. FIGS. 6A, 6B, 6C, and 6D are schematic views showing a process for forming capacitor elements of the solid electrolytic capacitor according to the first embodiment. FIGS. 7A and 7B are external views of a multi-layered capacitor element. FIG. 8 is an external perspective view showing the shape of a cathode electrode before singulation. FIG. 9 is an external perspective view showing the shape of a cathode electrode before singulation in a multi-layered state. FIG. 10 is a flowchart showing an example of a sheet laminate forming process. FIG. 11 is an exploded perspective view showing a structure in which capacitor element sheets and cathode electrodes are laminated. FIG. 12 is an exploded perspective view showing a state in which capacitor element sheets and cathode electrode sheets are laminated. FIG. 13(A) is a diagram showing the shapes of the anode electrode and dielectric layer of the capacitor element before singulation of the solid electrolytic capacitor according to the second embodiment, and FIG. 13(B) is a diagram showing the shape of the cathode electrode sheet according to the second embodiment.

[0018] First Embodiment A method for manufacturing a solid electrolytic capacitor according to a first embodiment of the present invention and a solid electrolytic capacitor manufactured by this manufacturing method will be described with reference to the drawings.

[0019] (Explanation of Schematic Configuration of Solid Electrolytic Capacitor 1) First, the structure of a solid electrolytic capacitor manufactured by a method for manufacturing a solid electrolytic capacitor according to an embodiment of the present invention will be described. FIG. 1 is a side cross-sectional view showing the configuration of a solid electrolytic capacitor according to a first embodiment. Note that in FIG. 1, only the insulating resin and external electrodes are hatched to make the drawing easier to see. FIGS. 2(A) and 2(B) are side cross-sectional views showing the configuration of a set of capacitor elements and cathode electrodes before singulation.

[0020] As shown in Figures 1, 2(A), and 2(B), the solid electrolytic capacitor 1 includes a capacitor element laminate 100, an insulating resin 50, an external electrode 61, and an external electrode 62. The capacitor element laminate 100 includes a plurality of flat-film capacitor elements 10 and a plurality of flat-film cathode electrodes 20. Note that the number (number) of flat-film capacitor elements 10 and cathode electrodes is not limited to that shown in Figure 1. The side cross-sectional views in Figures 1, 2(A), and 2(B) are cross-sectional views taken along a plane perpendicular to the top surface 101 and bottom surface 102 of the capacitor element laminate 100 in Figure 1. This flat-film cathode electrode 20 corresponds to the "cathode electrode foil" of the present invention.

[0021] 2(B), capacitor element 10 includes flat film anode electrode 11, dielectric layer 12, and CP layer (solid electrolyte layer) 13. Flat film anode electrode 11 corresponds to the "anode electrode foil" of the present invention.

[0022] Although detailed structural illustrations are omitted in Figures 2(A) and 2(B), the anode electrode 11 has numerous pores. In other words, the anode electrode 11 is porous (a porous body). The thickness ratio of the porous portion on one side of the anode electrode 11 to the core metal portion and the porous portion on the other side is approximately 1:1:1. A dielectric layer 12 covers the outer surface of the anode electrode 11. Because detailed structural illustrations of the anode electrode 11 are omitted in Figures 2(A) and 2(B), the dielectric layer 12 is schematically illustrated as covering the macroscopic surface of the anode electrode 11. In reality, the dielectric layer 12 covers not only the macroscopic surface of the anode electrode 11 but also the inner surfaces of the numerous pores in the anode electrode 11.

[0023] The CP layer 13 covers the surface of the dielectric layer 12. A frame-shaped CP dam 14 is formed on the outer periphery of the CP layer 13. The CP dam 14 has insulating properties. The CP dam 14 limits the area in which the CP layer 13 is formed.

[0024] The CP layer 13 has a laminated structure of an inner layer CP (inner layer solid electrolyte layer) 131 and an outer layer CP (outer layer solid electrolyte layer) 132. The inner layer CP 131 is formed on the surface of the dielectric layer 12, and the outer layer CP 132 is formed on the surface of the inner layer CP 131.

[0025] Multiple capacitor elements 10 and multiple cathode electrodes 20 are alternately stacked so that their flat film surfaces are parallel and overlap in a planar view. In this case, the outer layer CP132 of the capacitor element and the cathode electrode 20 are directly connected. In the structure shown in FIG. 2A , the outer layer CP132 of the capacitor element 10 and the cathode electrode 20 are bonded so as to abut against each other. This allows adjacent capacitor elements 10 and cathode electrodes 20 to be bonded and electrically connected. By stacking the capacitor elements 10 and the cathode electrodes 20 in this manner without using an adhesive, the thickness of the solid electrolytic capacitor 1 can be reduced. Note that if the adhesive does not affect the thickness of the solid electrolytic capacitor 1, the capacitor elements 10 and the cathode electrodes 20 may be bonded using an adhesive.

[0026] In this stacked state, the first ends 10E1 (see FIG. 1) of the plurality of capacitor elements 10 are located at approximately the same position in side view. Similarly, the second ends 10E2 (see FIG. 1) of the plurality of capacitor elements 10 are located at approximately the same position in side view. Furthermore, the first ends 20E1 (see FIG. 1) of the plurality of cathode electrodes 20 are located at approximately the same position in side view. Similarly, the second ends 20E2 (see FIG. 1) of the plurality of cathode electrodes 20 are located at approximately the same position in side view.

[0027] The first ends 10E1 of the plurality of capacitor elements 10 and the second ends 20E2 of the plurality of cathode electrodes 20 are arranged on the first end 10E1 side of the capacitor element stack 100. The first ends 10E1 of the plurality of capacitor elements 10 protrude outward beyond the second ends 20E2 of the plurality of cathode electrodes 20.

[0028] The second ends 10E2 of the plurality of capacitor elements 10 and the first ends 20E1 of the plurality of cathode electrodes 20 are arranged on the second end 10E2 side of the capacitor element stack 100. The first ends 20E1 of the plurality of cathode electrodes 20 protrude outward beyond the second ends 10E2 of the plurality of capacitor elements 10.

[0029] With this structure, a capacitor element stack 100 having a top surface 101 and a bottom surface 102 at both ends in the stacking direction of the plurality of capacitor elements 10 and the plurality of cathode electrodes 20 is realized.

[0030] The capacitor element laminate 100 is sealed with insulating resin 50. The sealing step will be described in more detail later.

[0031] The external electrode 61 covers a first end of the insulating resin 50 (first ends 10E1 of the anode electrodes 11). The external electrode 61 is connected to the first ends 10E1 of the anode electrodes 11 of the plurality of capacitor elements 10. The external electrode 62 covers a second end of the insulating resin 50 (first ends 20E1 of the cathode electrodes 20). The external electrode 62 is connected to the first ends 20E1 of the plurality of cathode electrodes 20.

[0032] The solid electrolytic capacitor 1 is realized by the above configuration.

[0033] (Method for Manufacturing Solid Electrolytic Capacitor 1) The solid electrolytic capacitor 1 having the above-described configuration is manufactured, for example, as follows. Fig. 3 is a flowchart showing an example of a schematic flow of a method for manufacturing the solid electrolytic capacitor according to this embodiment. Fig. 4 is an external perspective view showing a state in which the capacitor element sheet and the cathode electrode sheet are laminated.

[0034] A capacitor element sheet is formed (FIG. 3: S11). A plurality of capacitor elements 10, each forming a different solid electrolytic capacitor 1, are formed in an array on the capacitor element sheet (see FIGS. 7(A) and 7(B) described below).

[0035] Next, as shown in Fig. 4, the capacitor element sheet and the cathode electrode sheet are laminated to form a sheet laminate (Fig. 3: S12). Note that the cathode electrode sheet has a plurality of cathode electrodes 20 formed thereon, each of which forms a different solid electrolytic capacitor 1, arranged in an array (see Fig. 9 described below). This forms a structure in which a plurality of capacitor element laminates 100 are arranged in a plane. In other words, the sheet laminate is a structure in which a plurality of capacitor element laminates 100 are arranged in a plane.

[0036] Next, the sheet stack is sealed with insulating resin 50 (FIG. 3: S13). As will be described in detail later, at this time, through holes that penetrate from the top surface to the bottom surface of the sheet stack are provided in the sheet stack, and resin sealing is performed by compression molding.

[0037] The process up to this sealing with insulating resin 50 is carried out in a multi-state (state in which a plurality of what will become solid electrolytic capacitors 1 are arranged) before the solid electrolytic capacitor 1 is divided into individual pieces.

[0038] Next, the sheet laminate sealed with insulating resin 50 is cut into individual pieces ( S14 in FIG. 3 ). Specifically, cutting is performed along cutting lines S11, S12, E11, and E12 shown in FIG. 4 . This results in the formation of multiple solid electrolytic capacitors 1 (referred to as "solid electrolytic capacitor 1 bodies") without external electrodes. In other words, the anode electrodes 11 and cathode electrodes 20 that are unnecessarily exposed during singulation are covered with insulating resin 50. Cutting lines S11 and S12 correspond to the "first cutting lines" of the present invention, and cutting lines E11 and E12 correspond to the "second cutting lines" of the present invention.

[0039] Next, external electrodes 61 and 62 are formed on the end surfaces of the element body of solid electrolytic capacitor 1 (FIG. 3: S15).

[0040] Next, each step will be described in more detail.

[0041] (Capacitor Element Sheet Forming Process) Fig. 5 is a flowchart showing an example of a capacitor element sheet forming process. Figs. 6(A), 6(B), 6(C), and 6(D) are schematic views showing the process of forming the capacitor elements of the solid electrolytic capacitor according to the first embodiment. Figs. 7(A) and 7(B) are external views of the capacitor elements in a multi-layered state. Note that Figs. 6(A), 6(B), 6(C), and 6(D) show portions of the capacitor elements in a multi-layered state.

[0042] As shown in Fig. 6(A), anode 11 is subjected to chemical conversion treatment to form dielectric layer 12 (Fig. 5: S111). At this time, numerous holes are formed in the surface of anode 11 by etching, making the surface of anode 11 porous. Dielectric layer 12 covers the surface of anode 11, including the inner surfaces of the holes.

[0043] Next, a CP layer (solid electrolyte layer) 13 is formed on the surface of the dielectric layer 12 (FIG. 5: S112). More specifically, as shown in FIG. 6B, a CP dam 14 having a frame-shaped opening is formed. Then, as shown in FIG. 6C, a CP layer 13 (a laminated structure of an inner layer CP 131 and an outer layer CP 132) is formed within the opening of the CP dam 14.

[0044] Next, as shown in FIG. 6(D), anode through holes are formed in the anode electrode 11 (FIG. 5: S113). More specifically, as shown in FIGS. 6(D), 7(A), and 7(B), a plurality of cylindrical anode through holes 19C, groove-shaped anode through holes 19L, and groove-shaped anode through holes 19W are formed in the anode electrode 11. At this time, the plurality of cylindrical anode through holes 19C, groove-shaped anode through holes 19L, and groove-shaped anode through holes 19W penetrate not only the anode electrode 11 but also the CP dam 14. The plurality of cylindrical anode through holes 19C and groove-shaped anode through holes 19L are alternately arranged along the direction of the second cutting line along which the portions that will become the plurality of anode electrodes 11 are aligned. The plurality of cylindrical anode through holes 19C are formed at a position that will realize the first end 10E1 of the anode electrode 11. The groove-shaped anode through-hole 19L is formed at a position that straddles the portions that will become adjacent anode electrodes 11 and at a position that will realize the second ends 10E2 of the adjacent anode electrodes 11.

[0045] Furthermore, groove-shaped anode through holes 19W are continuously formed along the direction of the first cutting line (the direction perpendicular to the second cutting line) along which the portions that will become the multiple anode electrodes 11 are arranged. More specifically, groove-shaped anode through holes 19W are formed along the direction of the first cutting line at positions sandwiched between the positions at which the multiple cylindrical anode through holes 19C are formed and the positions at which groove-shaped anode through holes 19L are formed.

[0046] This structure is implemented in a multi-state in which multiple capacitor elements 10 (a structure consisting of an anode electrode 11, a dielectric layer 12, a CP layer 13, and a CP dam 14) are arranged two-dimensionally, as shown in Figures 7(A) and 7(B).

[0047] In the above configuration, the CP dam 14 is formed in step S112, and then the anode through-hole is formed in the anode electrode 11 in step S113. However, the CP dam 14 may be formed after the anode through-hole is formed in the anode electrode 11 so as not to block the anode through-hole.

[0048] (Cathode Electrode Sheet Forming Process) Fig. 8 is a perspective view showing the shape of the cathode electrode before being divided into individual pieces, and Fig. 9 is a perspective view showing the shape of the cathode electrode in a multi-piece state before being divided into individual pieces.

[0049] 8 and 9 , a plurality of cylindrical cathode through holes 29C, groove-shaped cathode through holes 29L, and groove-shaped cathode through holes 29W are formed in the cathode electrode 20. The cylindrical cathode through holes 29C and the groove-shaped cathode through holes 29L are alternately arranged along the direction of the second cutting line along which the portions that will become the cathode electrodes 20 are arranged. The groove-shaped cathode through holes 29W are continuously formed along the direction of the first cutting line along which the portions that will become the cathode electrodes 20 are arranged (a direction perpendicular to the second cutting line). More specifically, the groove-shaped cathode through holes 29W are formed at positions sandwiched between the cylindrical cathode through holes 29C and the groove-shaped cathode through holes 29L along the direction of the first cutting line.

[0050] The plurality of cylindrical cathode through-holes 29C are formed at positions that will realize first ends 20E1 of the cathode electrodes 20. The groove-shaped cathode through-holes 29L are formed at positions that straddle portions that will become adjacent cathode electrodes 20 and at positions that will realize second ends 20E2 of adjacent cathode electrodes 20.

[0051] (Sheet Laminate Forming Process) Fig. 10 is a flowchart showing an example of a sheet laminate forming process. Fig. 11 is an exploded perspective view showing a structure in which capacitor element sheets and cathode electrodes are laminated. Fig. 12 is an exploded perspective view showing a state in which capacitor element sheets and cathode electrode sheets are laminated.

[0052] 11 and 12, capacitor element sheets and cathode electrode sheets are alternately stacked (FIG. 10: S121). More specifically, the capacitor element sheets and cathode electrode sheets are stacked so as to satisfy the following conditions:

[0053] When viewed in the stacking direction, the plurality of cylindrical anode through holes 19C in the capacitor element sheet overlap with the groove-shaped cathode through holes 29L in the cathode electrode sheet (see FIG. 11 ). When viewed in the stacking direction, the groove-shaped anode through holes 19L in the capacitor element sheet overlap with the plurality of cylindrical cathode through holes 29C in the cathode electrode sheet (see FIG. 11 ). When viewed in the stacking direction, the groove-shaped anode through holes 19L in the capacitor element sheet overlap with the groove-shaped cathode through holes 29L in the cathode electrode sheet (see FIG. 11 ). When viewed in the stacking direction, the groove-shaped anode through holes 19W in the capacitor element sheet overlap with the groove-shaped cathode through holes 29W in the cathode electrode sheet (see FIG. 11 ).

[0054] Therefore, a plurality of through holes are formed in the sheet laminate, penetrating from the top surface to the bottom surface of the sheet laminate. The sheet laminate is filled with insulating resin (step S13 in FIG. 3 ). As a result, the plurality of cylindrical anode through holes 19C, groove-shaped anode through holes 19L, and groove-shaped anode through holes 19W in the capacitor element sheet are filled with insulating resin. Similarly, the plurality of cylindrical cathode through holes 29C, groove-shaped cathode through holes 29L, and groove-shaped cathode through holes 29W in the cathode electrode sheet are filled with insulating resin.

[0055] The sheet stack thus filled with insulating resin is divided into individual pieces in a single process in step S14 in FIG.

[0056] That is, the solid electrolytic capacitor can be formed by performing the sealing process with insulating resin (step S13 in FIG. 3) and the process of forming the solid electrolytic capacitor element by dividing it into individual pieces (step S14 in FIG. 3) once each. This allows for efficient formation of the solid electrolytic capacitor. Furthermore, since the number of times the dicing blade needs to be replaced due to dividing the capacitor into individual pieces can be reduced, the cost of replacing the dicing blade can be reduced. This improves the productivity of the solid electrolytic capacitor.

[0057] Furthermore, the shapes of the above-described plurality of cylindrical anode through holes 19C, groove-shaped anode through holes 19L, groove-shaped anode through holes 19W, plurality of cylindrical cathode through holes 29C, groove-shaped cathode through holes 29L, and groove-shaped cathode through holes 29W are very simple. That is, these through holes can be easily formed.

[0058] Furthermore, since a sufficient flow path for the insulating resin can be ensured, the insulating resin can be easily filled into the through holes.

[0059] The widths of groove-shaped anode through holes 19L, 19W, cathode through holes 29L, and cathode through holes 29W may be any size, more specifically, may be determined as long as they are within a range that can prevent short circuits between adjacent capacitor elements before singulation.

[0060] [Second Embodiment] A solid electrolytic capacitor and a method for manufacturing a solid electrolytic capacitor according to a second embodiment of the present invention will be described with reference to the drawings. Fig. 13(A) is a diagram showing the shapes of the anode electrode and dielectric layer of a capacitor element of a solid electrolytic capacitor 1A according to the second embodiment before singulation, and Fig. 13(B) is a diagram showing the shape of a cathode electrode sheet according to the second embodiment.

[0061] The solid electrolytic capacitor 1A according to the second embodiment differs from the solid electrolytic capacitor 1 according to the first embodiment in the shapes of the groove-shaped anode through holes 19Wa and the groove-shaped cathode through holes 29Wa. The other configuration of the solid electrolytic capacitor 1A is the same as that of the solid electrolytic capacitor 1, and a description of the same parts will be omitted.

[0062] 13A , a plurality of cylindrical anode through holes 19C, groove-shaped anode through holes 19L, and groove-shaped anode through holes 19Wa are formed in the anode 11. The cylindrical anode through holes 19C and the groove-shaped anode through holes 19L are alternately arranged along the direction of the second cutting line in the anode 11. The cylindrical anode through holes 19C are formed at positions that define first ends 10E1 of the anodes 11, and the groove-shaped anode through holes 19L are formed at positions that straddle portions that will become adjacent anodes 11 and at positions that define second ends 10E2 of adjacent anodes 11.

[0063] The groove-shaped anode through hole 19Wa is formed along the first cutting line and the second cutting line. More specifically, the groove-shaped anode through hole 19Wa has a first portion GP1 that is connected at a position where the first cutting line and the second cutting line intersect.

[0064] As a result, the multiple anode through holes 19L according to the first embodiment are replaced by portions of the multiple anode through holes 19Wa that have shapes along the second cutting lines and the multiple anode through holes 19L.

[0065] Furthermore, the groove-shaped anode through-holes 19Wa have second portions GP2 that are discontinuous in the direction of the first cutting line of the capacitor element sheet. That is, the second portions GP2 are portions where the anode electrodes 11 remain and partially connect the regions of the rows of the anode electrodes 11 that are adjacent to each other along the second cutting line. This reduces portions that are significantly weak in strength in the direction of the second cutting line, thereby increasing the strength of the capacitor element sheet.

[0066] 13(B) , the cathode electrode 20 has a plurality of cylindrical cathode through holes 29C, groove-shaped cathode through holes 29L, and groove-shaped cathode through holes 29Wa formed therein. The cylindrical cathode through holes 29C and the groove-shaped cathode through holes 29L are alternately arranged along the direction of the second cutting line. The groove-shaped cathode through holes 29Wa are formed along the directions of the first cutting line and the second cutting line. More specifically, the groove-shaped cathode through holes 29Wa have first portions GP1 that are connected at positions where the directions of the first cutting line and the second cutting line intersect.

[0067] As a result, the plurality of cathode through holes 29L according to the first embodiment are replaced by portions of the plurality of cathode through holes 29Wa that have shapes along the second cutting lines and the plurality of cathode through holes 29L.

[0068] Furthermore, the groove-shaped cathode through-holes 29Wa have second portions GP2 that are discontinuous in the direction of the first cutting line of the cathode electrode sheet. That is, the second portions GP2 are portions where the cathode electrodes 20 remain and partially connect regions of adjacent rows of the cathode electrodes 20 along the second cutting line. This reduces portions that are significantly weak in strength in the direction of the second cutting line, thereby increasing the strength of the cathode electrode sheet.

[0069] The capacitor element sheet and the cathode electrode sheet shown in Figures 13(A) and 13(B) are laminated together so as to satisfy the following conditions.

[0070] When viewed in the stacking direction, the plurality of cylindrical anode through holes 19C in the capacitor element sheet overlap with the groove-shaped cathode through holes 29L and portions of the groove-shaped cathode through holes 29Wa in the cathode electrode sheet that are aligned along the second cutting line. When viewed in the stacking direction, the groove-shaped anode through holes 19L and portions of the groove-shaped anode through holes 19Wa in the capacitor element sheet that are aligned along the second cutting line overlap with the plurality of cylindrical cathode through holes 29C in the cathode electrode sheet. When viewed in the stacking direction, the groove-shaped anode through holes 19L in the capacitor element sheet overlap with the groove-shaped cathode through holes 29L in the cathode electrode sheet. When viewed in the stacking direction, the portion of the groove-shaped anode through hole 19Wa in the capacitor element sheet that is aligned along the first cutting line overlaps with the portion of the groove-shaped cathode through hole 29Wa in the cathode electrode sheet that is aligned along the first cutting line.

[0071] With this configuration, the plurality of cylindrical anode through holes 19C, groove-shaped anode through holes 19L, and groove-shaped anode through holes 19Wa in the capacitor element sheet are filled with insulating resin. Similarly, the plurality of cylindrical cathode through holes 29C, groove-shaped cathode through holes 29L, and groove-shaped cathode through holes 29Wa in the cathode electrode sheet are filled with insulating resin.

[0072] Even with this configuration, the solid electrolytic capacitor 1A can be formed by performing the sealing process with insulating resin (step S13 in FIG. 3) and the process of forming the solid electrolytic capacitor element by dividing it into individual pieces (step S14 in FIG. 3) once each. This means that the solid electrolytic capacitor can be formed efficiently. Furthermore, since the number of times the dicing blade needs to be replaced due to dividing it into individual pieces can be reduced, the cost of replacing the dicing blade can be reduced. This improves the productivity of the solid electrolytic capacitor.

[0073] Furthermore, the shapes of the above-described plurality of cylindrical anode through holes 19C, groove-shaped anode through holes 19L, groove-shaped anode through holes 19Wa, and plurality of cylindrical cathode through holes 29C, groove-shaped cathode through holes 29L, and groove-shaped cathode through holes 29Wa are very simple, that is, these through holes can be easily formed.

[0074] Furthermore, since a sufficient flow path for the insulating resin can be ensured, the insulating resin can be easily filled into the through holes.

[0075] The widths of groove-shaped anode through holes 19L, 19Wa, groove-shaped cathode through holes 29L, and groove-shaped cathode through holes 29Wa may be any size, more specifically, may be determined as long as they are within a range that can prevent short circuits between adjacent capacitor elements before singulation.

[0076] (Explanation of an example of specific materials, etc., of each component of the solid electrolytic capacitor 1) (Capacitor element 10) The capacitor element 10 is realized, for example, using the following materials and with the following thicknesses.

[0077] The anode 11 is made of a metal such as aluminum, tantalum, niobium, titanium, zirconium, or magnesium, or an alloy containing any of these metals. The anode 11 is preferably made of aluminum or an aluminum alloy. The anode 11 may be made of any valve metal that exhibits a so-called valve action.

[0078] The anode 11 is preferably flat, and the thickness of the core (the center portion not reached by the pores of the porous body) of the anode 11 is preferably 5 μm or more and 100 μm or less. The thickness (thickness of one side) of the porous portion (the portion where the pores of the porous body are formed) is preferably 5 μm or more and 200 μm or less.

[0079] The dielectric layer 12 is preferably made of an oxide film of the anode electrode 11. For example, when an aluminum foil is used for the anode electrode 11, the dielectric layer 12 is formed by oxidizing the aluminum foil in an aqueous solution containing boric acid, phosphoric acid, adipic acid, or their sodium salts or ammonium salts. The thickness of the dielectric layer 12 is preferably 1 nm or more and 100 nm or less.

[0080] The inner layer CP131 may be a PEDOT:PSS layer realized by, for example, a conductive polymer having a skeleton of pyrroles, thiophenes, anilines, or the like, or a conductive polymer having a skeleton of thiophenes, such as PEDOT [poly(3,4-ethylenedioxythiophene)], and composited with polystyrene sulfonic acid (PSS) as a dopant. The inner layer CP131 may be formed, for example, by a method of forming a polymer film of poly(3,4-ethylenedioxythiophene) or the like on the surface of the dielectric layer 12 using a treatment liquid containing a monomer such as 3,4-ethylenedioxythiophene, or by a method of applying a dispersion of a polymer such as poly(3,4-ethylenedioxythiophene) to the surface of the dielectric portion and drying it.

[0081] The thickness of the outer layer CP 132 is preferably 2 μm or more and 20 μm or less. The material of the outer layer CP 132 is the same as the material of the inner layer CP 131.

[0082] The cathode electrode 20 is preferably made of aluminum or an aluminum alloy. The thickness of the cathode electrode 20 is, for example, approximately the same as the thickness of the anode electrode 11.

[0083] The insulating resin 50 may contain a filler. Examples of suitable resins include epoxy resin, phenol resin, polyimide resin, silicone resin, polyamide resin, and liquid crystal polymer. Examples of suitable fillers include insulating oxide particles such as silica particles, alumina particles, titania particles, and zirconia particles. The maximum diameter of the filler is preferably 30 μm or more and 40 μm or less. For example, a material containing silica particles in a solid epoxy resin is more preferable.

[0084] DESCRIPTION OF SYMBOLS 1, 1A...Solid electrolytic capacitor 10...Capacitor element 10E1, 20E1...First end 10E2, 20E2...Second end 11...Anode electrode 12...Dielectric layer 13...CP layer 131...Inner layer CP 132...Outer layer CP 14...CP dam 19C, 19L, 19W, 19Wa...Anode through-hole 20...Cathode electrode 29C, 29L, 29W, 29Wa...Cathode through-hole 50...Insulating resin 61, 62...External electrode 100...Capacitor element laminate 101...Top surface 102...Bottom surface E11, E12, S11, S12...Cutting line GP1...First portion GP2...Second portion

Claims

1. A step of sequentially forming a dielectric layer and a solid electrolyte layer on the surface of a flat film-shaped anode electrode foil to form a plurality of flat film-shaped capacitor elements; a step of forming an anode through-hole penetrating in the thickness direction of the plurality of flat film-shaped capacitor elements; a step of forming a cathode through-hole penetrating in the thickness direction of a flat film-shaped cathode electrode foil; a step of forming a sheet laminate by alternately laminating the plurality of flat film-shaped capacitor elements and the flat film-shaped cathode electrode foil via the solid electrolyte layer; a step of sealing the sheet laminate with an insulating resin; a step of cutting the sheet laminate sealed with the insulating resin into individual pieces with a first cutting line and a second cutting line orthogonal to the first cutting line, the anode through-hole and the cathode through-hole are formed along the first cutting line and the second cutting line, and in the step of forming the sheet laminate, the anode through-hole and the cathode through-hole are laminated so as to overlap each other in the thickness direction. A method for manufacturing a solid electrolytic capacitor.

2. The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein at least a part of the anode through-hole and the cathode through-hole has a shape that is continuously connected along the first cutting line.

3. The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein at least a part of the anode through-hole and the cathode through-hole has a shape having a connecting region in a region where the first cutting line and the second cutting line intersect.

4. A dielectric layer and a solid electrolyte layer are sequentially formed on the surface of a flat film-shaped anode electrode foil. A plurality of flat film-shaped capacitor elements, an anode through-hole penetrating the plurality of flat film-shaped capacitor elements in the thickness direction, a cathode through-hole penetrating the flat film-shaped cathode electrode foil in the thickness direction, a sheet laminate formed by alternately laminating the plurality of flat film-shaped capacitor elements and the flat film-shaped cathode electrode foil via the solid electrolyte layer, and an insulating resin for sealing the sheet laminate are provided. The sheet laminate sealed with the insulating resin is separated into individual pieces by a first cutting line and a second cutting line orthogonal to the first cutting line. The anode through-hole and the cathode through-hole are formed along the first cutting line and the second cutting line, and the anode through-hole and the cathode through-hole are laminated so as to overlap each other in the thickness direction. A solid electrolytic capacitor.

5. The solid electrolytic capacitor according to claim 4, wherein at least a part of the anode through-hole and the cathode through-hole has a shape that is continuously connected along the first cutting line.

6. The solid electrolytic capacitor according to claim 4, wherein at least a part of the anode through-hole and the cathode through-hole has a shape having a connecting region in a region where the first cutting line and the second cutting line intersect.

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