Solid electrolytic capacitor

Abstract

The utility model provides a solid electrolytic capacitor capable of suppressing short circuit between an anode and a cathode and realizing high reliability. A solid electrolytic capacitor is provided with: a sheet laminate formed by alternately laminating a plurality of flat film-like capacitor elements and a plurality of flat film-like cathode electrode foils with a conductive adhesive interposed therebetween; and an insulating resin that seals the sheet laminate. A flat-film-shaped capacitor element is provided with: a flat-film-shaped electrode foil for an anode; a dielectric layer formed on the surface of the anode electrode foil; a first partition wall formed on the surface of the dielectric layer; and a solid electrolyte layer formed in a region limited by the first partition wall. The conductive adhesive is formed in a region restricted by a second partition wall overlapping at least the first partition wall. The second partition wall is formed so as to cover the boundary between the solid electrolyte layer and the first partition wall.

Description

Technical Field

[0001] The present utility model 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. Background Art

[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-like capacitor elements and a plurality of metal foils (cathodes). The flat film-like capacitor element includes a foil-like valve-acting metal substrate, a porous portion formed on the valve-acting metal substrate, a dielectric layer formed on the surface of the porous portion, and a solid electrolyte layer formed on the surface of the dielectric layer.

[0003] More specifically, it has the following structure. On the surface of the dielectric layer in Patent Document 1, a mask layer covering the ends and sides of each element region is formed. A solid electrolyte layer is formed in the region surrounded by the mask layer. Further, an insulating adhesive layer is formed so as to overlap with the mask layer, and a conductor layer is formed on the solid electrolyte layer.

[0004] The flat film-like capacitor elements and metal foils formed in this way are alternately laminated to form an element laminate. The element laminate is sealed with an insulating resin.

[0005] Patent Document 2 describes a surface-mounted thin capacitor. The cathode portion of the surface-mounted thin capacitor described in Patent Document 2 is formed by laminating a conductive polymer, a graphite layer, and a silver paste layer on the surface of an anode (aluminum foil). A resist resin is formed at the boundary between the anode (aluminum foil) and the cathode portion. An insulating resin is formed so as to cover a part of the resist resin.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-79866

[0009] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2009-129936 Summary of the Utility Model

[0010] Problems to be Solved by the Utility Model

[0011] However, in the solid electrolytic capacitor shown in Patent Document 1, when laminating a flat film-shaped capacitor element and a valve metal substrate (metal foil) having a dielectric layer formed on its surface, wetting spread of the conductor layer occurs. At this time, if there is a gap at the boundary between the mask layer and the solid electrolyte layer, the dielectric layer may be exposed. In addition, even when there is no gap between the mask layer and the solid electrolyte layer when forming the mask layer and the solid electrolyte layer, the mask layer and the solid electrolyte layer sometimes shrink due to heat and pressure treatment during subsequent lamination or the like. That is, the boundary between the mask layer and the solid electrolyte layer may be exposed, so that the conductor layer and the valve metal substrate come into contact. As a result, the leakage current increases and a short circuit may occur.

[0012] On the other hand, in the surface-mounted thin capacitor shown in Patent Document 2, as described above, an insulating resin is formed so as to cover a part of the resist resin that forms the boundary between the anode and the cathode portion. However, since the insulating resin only covers a part of the resist resin, when reformation is performed, the resist resin and the conductive polymer shrink, so that the formation liquid enters between the resist resin and the conductive polymer. As a result, a gap appears between the resist resin and the conductive polymer. Therefore, in the structure of Patent Document 2, the same problem as in Patent Document 1 may also occur.

[0013] Therefore, an object of the present utility model is to provide a solid electrolytic capacitor capable of suppressing a short circuit between the anode and the cathode and achieving high reliability.

[0014] Technical solution for solving the problem

[0015] The solid electrolytic capacitor of the present utility model includes: a sheet laminate formed by alternately laminating a plurality of flat film-shaped capacitor elements and a plurality of flat film-shaped cathode electrode foils with a conductive adhesive interposed therebetween; and an insulating resin for sealing the sheet laminate. The flat film-shaped capacitor element includes: a flat film-shaped anode electrode foil; a dielectric layer formed on the surface of the anode electrode foil; a first partition wall formed on the surface of the dielectric layer; and a solid electrolyte layer formed in a region restricted by the first partition wall. The conductive adhesive is formed in a region restricted by a second partition wall that at least overlaps the first partition wall. The second partition wall is formed to cover the boundary between the solid electrolyte layer and the first partition wall.

[0016] By having this structure, even when laminating the capacitor element and the cathode electrode foil with the conductive adhesive, it is possible to suppress the conductive adhesive from coming into contact with the solid electrolyte layer. That is, a short circuit between the anode and the cathode can be suppressed.

[0017] Effect of the utility model

[0018] Therefore, according to the present utility model, it is possible to provide a solid electrolytic capacitor that can suppress a short circuit between the anode and the cathode and achieve high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. 1 is a side cross-sectional view showing the structure of the solid electrolytic capacitor according to the first embodiment.

[0020] FIG. 2(A) is a side cross-sectional view showing the structure of a group of capacitor elements and a cathode electrode before monolithic integration, FIG. 2(B) is a side cross-sectional view showing the structure of the capacitor element before monolithic integration, and FIG. 2(C) is a side cross-sectional view showing the structure of a group of capacitor elements and a cathode electrode after monolithic integration.

[0021] FIG. 3(A) is a diagram schematically showing the structure of the capacitor element and the cathode electrode of the present utility model, and FIG. 3(B) is a diagram schematically showing the structure of the capacitor element and the cathode electrode of the conventional structure.

[0022] FIG. 4(A) is a top view schematically showing the structure of the capacitor element and the cathode electrode of the present utility model, and FIG. 4(B) is a top view schematically showing the structure of the capacitor element and the cathode electrode of the conventional structure.

[0023] Figure 5 FIG. 5 is a flowchart showing an example of a schematic process of the manufacturing method of the solid electrolytic capacitor according to the present embodiment.

[0024] Figure 6 FIG. 6 is a flowchart showing an example of the forming process of the capacitor element sheet.

[0025] FIG. 7(A) is an external perspective view showing the shape of the anode electrode and the dielectric layer of the capacitor element before monolithic integration, and FIG. 7(B) is an external perspective view showing the shape of the capacitor element before monolithic integration.

[0026] Figure 8 FIG. 8 is an external view in a multi-sheet state.

[0027] Figure 9 FIG. 9 is an external perspective view showing the shape of the cathode electrode before monolithic integration.

[0028] Figure 10 FIG. 10 is a flowchart showing an example of the forming process of the sheet laminate.

[0029] FIG. 11(A) and FIG. 11(B) are external perspective views showing the state where the second partition wall is formed in the capacitor element sheet.

[0030] FIG. 12(A) and FIG. 12(B) are external perspective views showing the state where the second partition wall and the adhesive are formed in the capacitor element sheet.

[0031] FIG. 13(A) and FIG. 13(B) are exploded perspective views showing the state of laminating a capacitor element sheet and a cathode electrode sheet.

[0032] FIG. 14(A) is an exploded perspective view showing the laminated state of the capacitor element sheet and the cathode electrode sheet in a multi-sheet state, and FIG. 14(B) is an external perspective view showing the laminated state of the capacitor element sheet and the cathode electrode sheet in a multi-sheet state.

[0033] Figure 15 is an exploded perspective view showing the state of the capacitor element sheet and the cathode electrode sheet in a multi-sheet state.

[0034] FIG. 16(A) is a side cross-sectional view showing the structure of a group of a capacitor element and a cathode electrode before singulation in the second embodiment, and FIG. 16(B) is a side cross-sectional view showing the structure of the capacitor element before singulation. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] [First Embodiment]

[0036] The solid electrolytic capacitor according to the first embodiment of the present invention and a method for manufacturing the solid electrolytic capacitor will be described with reference to the drawings.

[0037] (Description of the schematic structure of the solid electrolytic capacitor 1)

[0038] First, the structure of the solid electrolytic capacitor according to the embodiment of the present invention will be described. Figure 1 is a side cross-sectional view showing the structure of the solid electrolytic capacitor according to the first embodiment. In addition, in Figure 1 , for easy observation of the drawings, only the insulating resin and the external electrodes are hatched. FIG. 2(A) is a side cross-sectional view showing the structure of a group of a capacitor element and a cathode electrode before singulation. FIG. 2(B) is a side cross-sectional view showing the structure of the capacitor element before singulation. FIG. 2(C) is a side cross-sectional view showing the structure of a group of the capacitor element and the cathode electrode after singulation.

[0039] As Figure 1 , FIG. 2(A), FIG. 2(B), and FIG. 2(C) show, 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-like capacitor elements 10, a plurality of flat film-like cathode electrodes 20, a second partition wall 30, and an adhesive 40. In addition, in Figure 1In this case, the number of flat film-like capacitor elements 10 and cathode electrodes (number of sheets) is 4 respectively, but it is not limited thereto. In addition, the cathode electrode 20 corresponds to the "cathode electrode foil" in the present utility model. Figure 1 , the side cross-sectional views in FIGS. 2(A), 2(B), and 2(C) are cross-sectional views based on a plane orthogonal to the top surface 101 and the bottom surface 102 of the capacitor element laminate 100 in Figure 1 .

[0040] As shown in FIG. 2(B), the capacitor element 10 includes a flat film-like anode electrode 11, a dielectric layer 12, and a CP layer (solid electrolyte layer) 13.

[0041] In FIGS. 2(A), 2(B), and 2(C), although the illustration of the detailed structure is omitted, the anode electrode 11 has many holes. In other words, the anode electrode 11 is in a porous state (porous body). The thickness ratio of the porous part, the core part, and the porous part on the other side of one side of the anode electrode 11 is about 1:1:1. The dielectric layer 12 covers the outer surface of the anode electrode 11. In FIGS. 2(A), 2(B), and 2(C), the illustration of the detailed structure of the anode electrode 11 is omitted, so the dielectric layer 12 is schematically illustrated as covering the macroscopic surface of the anode electrode 11. In fact, the dielectric layer 12 not only covers the macroscopic surface of the anode electrode 11, but also covers the surfaces of many holes of the anode electrode 11. In addition, the anode electrode 11 corresponds to the "anode electrode foil" in the present utility model.

[0042] The CP layer 13 covers the surface of the dielectric layer 12. The CP layer 13 is formed inside the frame-shaped first partition wall 14. The first partition wall 14 has insulation. The formation region of the CP layer 13 is restricted by the first partition wall 14. In addition, in the first embodiment, as described in the manufacturing method described later, after the first partition wall 14 is formed in a frame shape, the CP layer 13 is formed inside the first partition wall 14. However, according to the manufacturing method of the capacitor element 10 (for example, the case where the capacitor element 10 is manufactured in a state of being singulated from the beginning, etc.), the first partition wall 14 may not be formed in a frame shape. That is, the first partition wall 14 may be formed on one side, or may be formed on two sides having corners. Furthermore, it may also be a structure formed on two opposed sides in a plan view.

[0043] The CP layer 13 is 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.

[0044] A plurality of capacitor elements 10 and a plurality of cathode electrodes 20 are alternately stacked such that their respective flat film surfaces are parallel and overlap each other in a plan view.

[0045] Between adjacent capacitor elements 10 and cathode electrodes 20, a second partition wall 30 and an adhesive 40 are provided. The second partition wall 30 has insulation properties. The adhesive 40 has conductivity. In addition, the adhesive 40 corresponds to the "conductive adhesive" in the present invention.

[0046] The second partition wall 30 is in a frame shape. The adhesive 40 is disposed inside the frame defined by the second partition wall 30. Adjacent capacitor elements 10 and cathode electrodes 20 are bonded by this adhesive 40.

[0047] As shown in FIG. 2(B), the second partition wall 30 is formed to overlap with the outer layer CP132. In other words, it is formed to cover the end portion of the first partition wall 14 and the end portion of the outer layer CP132. A more detailed structure will be described later. In addition, the second partition wall 30 is made of an insulating material such as an insulating resin, for example.

[0048] The second partition wall 30 has a partition wall adjustment portion 30L. This partition wall adjustment portion 30L is used to control the volume when the second partition wall 30 is coated. In other words, by using the partition wall adjustment portion 30L, unnecessary expansion of the second partition wall 30 during lamination can be suppressed. Due to the unnecessary expansion of the second partition wall 30, the second partition wall 30 may enter, for example, into the anode through holes 19C, 19L, the cathode through holes 29C, 29L (the detailed structure is shown below). However, by having the partition wall adjustment portion 30L, molding defects caused by hindrance of molding using the insulating resin 50 can be suppressed.

[0049] The partition wall adjustment portion 30L is formed by a printed pattern. The partition wall adjustment portion 30L can be a through hole or can have a shape with a bottom surface in the second partition wall 30 like a recess. In addition, it is appropriate to form the size (width, length) of the partition wall adjustment portion 30L according to the volume of the second partition wall 30.

[0050] In addition, by heating and pressing the capacitor element 10 and the cathode electrode 20, the second partition wall 30 expands. As a result, the thickness difference between the partition wall adjustment portion 30L and other portions becomes smaller.

[0051] In such a stacked state, the first ends 10E1 of the plurality of capacitor elements 10 (see FIG. 2(C)) are in substantially the same position in a side view. Similarly, the second ends 10E2 of the plurality of capacitor elements 10 (see FIG. 2(C)) are in substantially the same position in a side view. Further, the first ends 20E1 of the plurality of cathode electrodes 20 (see FIG. 2(C)) are in substantially the same position in a side view. Similarly, the second ends 20E2 of the plurality of cathode electrodes 20 (see FIG. 2(C)) are in substantially the same position in a side view.

[0052] 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 side of the capacitor element laminate 100. The first ends 10E1 of the plurality of capacitor elements 10 protrude outward more than the second ends 20E2 of the plurality of cathode electrodes 20.

[0053] 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 side of the capacitor element laminate 100. The first ends 20E1 of the plurality of cathode electrodes 20 protrude outward more than the second ends 10E2 of the plurality of capacitor elements 10.

[0054] With such a configuration, the capacitor element laminate 100 can be realized.

[0055] The capacitor element laminate 100 is sealed with an insulating resin 50. More specifically, the insulating resin 50 covers the capacitor element laminate 100 except for the first ends 10E1 of the plurality of capacitor elements 10 (the first ends 10E1 of the anode electrodes 11) and the first ends 20E1 of the plurality of cathode electrodes 20.

[0056] The external electrode 61 covers the first end of the insulating resin 50 (the first end 10E1 of the anode electrode 11). The external electrode 61 is connected to the first ends 10E1 of the anode electrodes 11 of the plurality of capacitor elements 10.

[0057] The external electrode 62 covers the second end of the insulating resin 50 (the first end 20E1 of the cathode electrode 20). The external electrode 62 is connected to the first ends 20E1 of the plurality of cathode electrodes 20.

[0058] With the above structure, the solid electrolytic capacitor 1 can be realized.

[0059] (Description of the detailed structure of the solid electrolytic capacitor 1)

[0060] Next, the detailed structures of the capacitor element 10 and the cathode electrode 20 that constitute the solid electrolytic capacitor 1 will be described with reference to FIGS. 3(A) and 3(B). FIG. 3(A) is a side cross-sectional view schematically showing the structures of the capacitor element 10 and the cathode electrode 20, and is a magnified view of the structure of FIG. 2(A) described above. FIG. 3(B) is a side cross-sectional view schematically showing the structures of the capacitor element 10 and the cathode electrode 20 based on a conventional structure. In FIGS. 3(A) and 3(B), the structure in which the cathode electrode 20 is disposed on one main surface of the capacitor element 10 is used for description. However, the same structure is also present on the other main surface opposed to the one main surface. The side cross-sectional views in FIGS. 3(A) and 3(B) are cross-sectional views based on a plane orthogonal to the top surface 101 and the bottom surface 102 of the capacitor element laminate 100 in Figure 1 .

[0061] In addition, regarding their respective structures, for ease of understanding of the description, each structure is shown enlarged and exaggerated. Further, although only one set of the capacitor element 10 and the cathode electrode 20 is shown in FIGS. 3(A) and 3(B), the solid electrolytic capacitor 1 is formed by laminating multiple sets of these.

[0062] As shown in FIG. 3(A), an outer layer CP132 is formed within the region surrounded by the first partition wall 14. There is a boundary portion BD at the boundary between the inner side of the region formed by the first partition wall 14 and the region where the outer layer CP132 is formed. Due to the presence of this boundary portion BD, the dielectric layer 12 is exposed. For convenience, the boundary portion BD and the portion where the dielectric layer 12 is exposed are shown as the same part.

[0063] However, in the present utility model, a second partition wall 30 is formed so as to cover this boundary portion BD. That is, even when the dielectric layer 12 is exposed, the second partition wall 30 enters the exposed portion. Thus, the dielectric layer 12 is not exposed.

[0064] By laminating the capacitor element 10 having this structure and a plurality of cathode electrodes 20 with an adhesive 40 interposed therebetween, contact between the adhesive 40 and the anode electrode 11 can be suppressed. That is, short-circuiting between the anode and the cathode can be suppressed.

[0065] Next, a more detailed structure will be described with reference to FIGS. 3(A), 4(A), and 4(B). FIG. 4(A) is a top view schematically showing the arrangement of the adhesive 40 in the capacitor element 10. FIG. 4(B) is a top view schematically showing the arrangement of the adhesive 40 in the capacitor element 10 in a conventional structure. In addition, in FIGS. 4(A) and 4(B), in order to easily explain the dielectric layer 12, the hatching is different from that in other figures. Regarding their respective structures, for ease of understanding of the description, each structure is shown enlarged and exaggerated.

[0066] As shown in FIGS. 3(A) and 4(A), the positional relationship between the inner peripheral portion 14P of the first partition wall 14 and the inner peripheral portion 30P of the second partition wall 30 is compared. In the present utility model, the inner peripheral portion 30P is formed over the entire circumference at a distance d inside the capacitor element 10 (the inner side in plan view) from the inner peripheral portion 14P. That is, the second partition wall 30 is formed to extend to a distance d inside the capacitor element 10 from the first partition wall 14. In addition, regarding the distance d, a range of about 50 μm to about 100 μm is appropriate.

[0067] By configuring in this way, the boundary portion BD is covered by the second partition wall 30. That is, even when the adhesive 40 undergoes wetting expansion due to processes such as heating and pressurization, the adhesive 40 does not come into contact with the dielectric layer 12 (boundary portion BD). That is, short - circuiting between the anode electrode 11 and the cathode electrode 20 can be suppressed.

[0068] (Method for manufacturing the solid electrolytic capacitor 1)

[0069] The solid electrolytic capacitor 1 having the above - described structure is manufactured, for example, as follows. Figure 5 FIG. is a flowchart showing an example of the schematic process of the method for manufacturing the solid electrolytic capacitor according to the present embodiment.

[0070] Forming a capacitor element sheet ( Figure 5 : S11). Regarding the capacitor element sheet, it is formed in a state where a plurality of capacitor elements 10 for forming respective different solid electrolytic capacitors 1 are arranged.

[0071] Next, sandwiching the adhesive 40, the capacitor element sheet and the cathode electrode sheet are laminated to form a sheet laminate ( Figure 5 : S12). In addition, regarding the cathode electrode sheet, it is formed in a state where a plurality of cathode electrodes 20 for forming respective different solid electrolytic capacitors 1 are arranged. Thereby, a structure in which a plurality of capacitor element laminates 100 are arranged in a plane is formed. In other words, the sheet laminate is a laminate in which a plurality of capacitor element laminates 100 are arranged in a plane.

[0072] Next, the sheet laminate is sealed with an insulating resin 50 ( Figure 5 : S13). At this time, when the sheet laminate has through - holes penetrating from the upper surface to the lower surface of the sheet laminate, resin sealing is performed by compression molding, which will be described in detail later.

[0073] Until sealing with this insulating resin 50 is performed, it is carried out in a multi - sheet state (a state in which a plurality of objects that will become the solid electrolytic capacitor 1 are arranged) before the solid electrolytic capacitor 1 is singulated.

[0074] Next, the sheet laminate sealed with the insulating resin 50 is cut to form individual sheets ( Figure 5 : S14). Specifically, cutting is performed along the cutting lines E11, E12, S11, and S12 shown in FIG. 13(B) described later. Thereby, a plurality of solid electrolytic capacitors 1 in a state where no external electrodes are formed (referred to as the body of the solid electrolytic capacitor 1) are formed. Then, the body of the solid electrolytic capacitor 1 is secondarily sealed with the insulating resin 50. More specifically, the side surface of the body of the solid electrolytic capacitor 1 is covered by the secondary sealing of the insulating resin 50 (the surfaces cut by the cutting lines S11 and S12 (sides different from the upper surface, the lower surface, and the end surfaces exposing the anode electrode 11 and the cathode electrode 20)). Thereby, the anode electrode 11 and the cathode electrode 20 that are unnecessarily exposed during singulation are covered with the insulating resin 50.

[0075] Next, an external electrode 61 and an external electrode 62 are formed on the end surface of the body of the solid electrolytic capacitor 1 ( Figure 5 : S15).

[0076] Next, each process will be described in more detail.

[0077] (Process for forming a capacitor element sheet)

[0078] Figure 6 is a flowchart showing an example of the process for forming a capacitor element sheet. FIG. 7(A) is an external perspective view showing the shape of the anode electrode and the dielectric layer of the capacitor element before singulation, and FIG. 7(B) is an external perspective view showing the shape of the capacitor element before singulation. Figure 8 is an external view in a multi-sheet state.

[0079] The anode electrode 11 is subjected to a forming treatment to form a dielectric layer 12 ( Figure 6 : S111). At this time, many holes are formed on the surface of the anode electrode 11 by etching, and the vicinity of the surface of the anode electrode 11 becomes a porous body. The dielectric layer 12 covers the surface of the anode electrode 11 including the inner surfaces of the holes.

[0080] Next, an anode through-hole is formed in the anode electrode 11 ( Figure 6: S112). More specifically, as shown in FIG. 7(A), a plurality of cylindrical through-holes 19C for the anode and groove-shaped through-holes 19L for the anode are formed in the anode electrode 11. The plurality of cylindrical through-holes 19C for the anode and the groove-shaped through-holes 19L for the anode are alternately arranged along the direction in which the portions forming the plurality of anode electrodes 11 are arranged. The plurality of cylindrical through-holes 19C for the anode are formed at the position where the first end 10E1 of the anode electrode 11 is realized, and the groove-shaped through-holes 19L for the anode are formed at the position straddling the portion between adjacent anode electrodes 11 and at the position where the second end 10E2 of the adjacent anode electrode 11 is realized.

[0081] Next, a CP layer (solid electrolyte layer) 13 is formed on the surface of the dielectric layer 12 ( Figure 6 : S113). More specifically, as shown in FIG. 7(B), a frame-shaped first partition wall 14 having an opening is formed. Then, a CP layer 13 (a laminated structure of an inner layer CP131 and an outer layer CP132) is formed inside the opening of the first partition wall 14.

[0082] Regarding this structure, as Figure 8 shown, it is carried out in a multi-chip state in which a plurality of capacitor elements 10 (a structure including an anode electrode 11, a dielectric layer 12, a CP layer 13, and a first partition wall 14) are two-dimensionally arranged.

[0083] (Process for forming the cathode electrode sheet)

[0084] Figure 9 is an external perspective view showing the shape of the cathode electrode before singulation.

[0085] As Figure 9 shown, a plurality of cylindrical through-holes 29C for the cathode and groove-shaped through-holes 29L for the cathode are formed in the cathode electrode 20. The plurality of cylindrical through-holes 29C for the cathode and the groove-shaped through-holes 29L for the cathode are alternately arranged along the direction in which the portions forming the plurality of cathode electrodes 20 are arranged. The plurality of cylindrical through-holes 29C for the cathode are formed at the position where the first end 20E1 of the cathode electrode 20 is realized, and the groove-shaped through-holes 29L for the cathode are formed at the position straddling the portion between adjacent cathode electrodes 20 and at the position where the second end 20E2 of the adjacent cathode electrode 20 is realized.

[0086] (Process for forming the sheet laminate)

[0087] Figure 10It is a flowchart showing an example of the process for forming a sheet laminate. FIGS. 11(A) and 11(B) are perspective external views showing the state where a second partition wall is formed in a capacitor element sheet. FIG. 11(A) shows a multi-sheet state, and FIG. 11(B) shows a part of a single capacitor element. FIGS. 12(A) and 12(B) are perspective external views showing the state where a second partition wall and an adhesive are formed in a capacitor element sheet. FIG. 12(A) shows a multi-sheet state, and FIG. 12(B) shows a part of a single capacitor element. FIGS. 13(A) and 13(B) are exploded perspective views showing the state where a capacitor element sheet and a cathode electrode sheet are laminated. FIGS. 13(A) and 13(B) show a part corresponding to a single solid electrolytic capacitor. FIG. 14(A) is an exploded perspective view showing the laminated state of a capacitor element sheet and a cathode electrode sheet in a multi-sheet state, and FIG. 14(B) is a perspective external view showing the laminated state of a capacitor element sheet and a cathode electrode sheet in a multi-sheet state. Figure 15 It is a diagram showing the structure after laminating a capacitor element sheet and a cathode electrode sheet and subjecting them to heat and pressure.

[0088] A second partition wall 30 is formed in the capacitor element sheet ( Figure 10 : S121). More specifically, as shown in FIGS. 11(A) and 11(B), a frame-shaped second partition wall 30 with an opening is formed. The second partition wall 30 is formed at a position overlapping the first partition wall 14. Further, the second partition wall 30 is formed to an area inside the inner frame of the first partition wall 14. However, as long as the second partition wall 30 expands to an area inside the inner frame of the first partition wall 14 during the subsequent heat and pressure application, the shape during printing is not limited to this.

[0089] At this time, the second partition wall 30 is formed by a printing pattern so as to have a partition wall adjustment portion 30L. In addition, in FIG. 11(A), an example where the partition wall adjustment portion 30L is formed over the entire first partition wall 14 is shown. However, it may also be a structure where the partition wall adjustment portion 30L is not formed over the entire first partition wall 14. That is, it may also be a configuration where, in the same manner as the size of the above-mentioned partition wall adjustment portion 30L, the number of partition wall adjustment portions 30L is formed according to the volume of the adhesive 40.

[0090] Next, as shown in FIGS. 12(A), 12(B), an adhesive 40 is disposed within the opening of the second partition wall 30 ( Figure 10 : S122).

[0091] Next, as shown in FIGS. 13(A), 13(B), 14(A), and 14(B), the capacitor element sheet and the cathode electrode sheet are alternately laminated ( Figure 10 : S123). More specifically, the capacitor element sheet and the cathode electrode sheet are laminated to satisfy the following conditions.

[0092] · When observed in the stacking direction, a plurality of cylindrical through-holes 19C for the anode in the capacitor element sheet and groove-shaped through-holes 29L for the cathode in the cathode electrode sheet overlap.

[0093] · When observed in the stacking direction, groove-shaped through-holes 19L for the anode in the capacitor element sheet and a plurality of cylindrical through-holes 29C for the cathode in the cathode electrode sheet overlap.

[0094] · When observed in the stacking direction, groove-shaped through-holes 19L for the anode in the capacitor element sheet and groove-shaped through-holes 29L for the cathode in the cathode electrode sheet overlap.

[0095] Moreover, a plurality of these through-holes are formed corresponding to the number of capacitor elements arranged in the sheet laminate. Therefore, a plurality of through-holes penetrating from the upper surface to the lower surface of the sheet laminate are formed in the sheet laminate.

[0096] Next, the sheet laminate is heated and pressed ( Figure 10 : S124). Thereby, the capacitor element sheet and the cathode electrode sheet are bonded by the adhesive 40 to form a sheet laminate. As Figure 15 shown, by this heating and pressing, the adhesive 40 spreads in a plane. However, since the second partition wall 30 covers the boundary portion BD, contact between the adhesive 40 and the anode electrode 11 can be suppressed. That is, short-circuiting between the anode and the cathode can be suppressed.

[0097] In addition, by this heating and pressing, the partition wall adjustment portion 30L formed in the second partition wall 30 is blocked. Thereby, the thickness of the second partition wall 30 can be adjusted, and an unnecessary increase in the thickness of the second partition wall 30 can be suppressed. Therefore, a reduction in the height of the sheet laminate can be achieved.

[0098] [Second Embodiment]

[0099] Next, the solid electrolytic capacitor according to the second embodiment will be described with reference to the drawings. FIG. 16(A) is a side cross-sectional view showing the structure of a group of a capacitor element and a cathode electrode before monolithicization in the second embodiment, and FIG. 16(B) is a side cross-sectional view showing the structure of the capacitor element before monolithicization.

[0100] As shown in FIGS. 16(A) and 16(B), the difference between the solid electrolytic capacitor 1A according to the second embodiment and the solid electrolytic capacitor 1 according to the first embodiment is that the cathode electrode 20A has a third partition wall 210. The other structures of the solid electrolytic capacitor 1A are the same as those of the solid electrolytic capacitor 1, and the description of the same parts is omitted.

[0101] As shown in Fig. 16(B) , the cathode electrode 20A includes a third partition wall 210. The third partition wall 210 is made of an insulating material such as an insulating resin, for example, similarly to the second partition wall 30.

[0102] The cathode electrode 20A and the capacitor element 10 are bonded by heating and pressing with the adhesive 40 interposed therebetween. Even with such a structure, the adhesive 40 and the anode electrode 11 can be prevented from contacting each other. The presence of the third partition wall 210 can further prevent the adhesive 40 from spreading from the cathode electrode 20A to the periphery.

[0103] (Description of an Example of Specific Materials and the Like of Each Component of the Solid Electrolytic Capacitor 1)

[0104] (Capacitor element 10)

[0105] Capacitor element 10 is realized by, for example, the following materials and thicknesses.

[0106] Anode electrode 11 is made of a single metal such as aluminum, tantalum, niobium, titanium, zirconium, magnesium, or an alloy containing these metals. Anode electrode 11 is preferably aluminum or an aluminum alloy. Anode electrode 11 may be any valve metal that exhibits a so-called valve action.

[0107] The anode electrode 11 is preferably in the form of a flat plate, and the thickness of the core portion (the central portion where the pores of the porous body do not reach) of the anode electrode 11 is preferably 5 μm to 100 μm. The thickness (single-side thickness) of the porous portion (the portion of the porous body where the pores are formed) is preferably 5 μm to 200 μm.

[0108] The dielectric layer 12 is preferably composed of an oxide film of the anode electrode 11. For example, when aluminum foil is used for the anode electrode 11, the dielectric layer 12 is formed by oxidizing it in an aqueous solution containing boric acid, phosphoric acid, adipic acid, or their sodium salts, ammonium salts, etc. The thickness of the dielectric layer 12 is preferably 1 nm or more and 100 nm or less.

[0109] The inner layer CP131 is realized by, for example, a conductive polymer having a pyrrole, thiophene, aniline or the like as a skeleton, or PEDOT [poly (3,4-ethylenedioxythiophene)] which is a conductive polymer having a thiophene as a skeleton, and may be a layer of PEDOT:PSS compounded with polystyrene sulfonic acid (PSS) as a dopant. The inner layer CP131 is formed by, for example, 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 of 3,4-ethylenedioxythiophene or the like, a method of applying a dispersion of a polymer of poly (3,4-ethylenedioxythiophene) or the like on the surface of the dielectric part and drying it, etc.

[0110] The thickness of the outer layer CP132 is preferably 2 μm or more and 20 μm or less. The material of the outer layer CP132 is the same as that of the inner layer CP131.

[0111] Regarding the adhesive 40, for example, a mixture of an insulating resin such as an epoxy resin or a phenolic resin and conductive particles such as carbon or silver is preferably used. Additionally, regarding the adhesive 40, a dispersion of a conductive polymer or a dispersion of a conductive polymer with an added binder may also be used.

[0112] The cathode electrode 20 is formed of, for example, aluminum, titanium, copper, silver, etc. The thickness of the cathode electrode 20 is, for example, thinner than the thickness of the anode electrode 11, or is about the same as the thickness of the anode electrode 11. Additionally, the thickness of the cathode electrode 20 is preferably as thin as possible, being in the range of 5 μm to 50 μm, preferably about 30 μm.

[0113] The insulating resin 50 may also contain a filler. As the resin, for example, an epoxy resin, a phenolic resin, a polyimide resin, a silicone resin, a polyamide resin, a liquid crystal polymer, etc. are preferably used. As the filler, for example, insulating oxide particles such as silica particles, alumina particles, titanium dioxide particles, zirconia particles, etc. are preferably used. The maximum diameter of the filler is, for example, preferably 30 μm or more and 40 μm or less. For example, a material containing silica particles in a solid epoxy resin and a phenolic resin is more preferably used.

[0114] Explanation of Reference Numerals

[0115] BD: Boundary portion;

[0116] d: Distance;

[0117] 1, 1A: Solid electrolytic capacitor;

[0118] 10: Capacitor element;

[0119] 10E1, 20E1: First terminal;

[0120] 10E2, 20E2: Second terminal;

[0121] 11: Anode electrode;

[0122] 12: Dielectric layer;

[0123] 14: First partition wall;

[0124] 14P: Inner peripheral portion;

[0125] 19C, 19L: Anode through-holes;

[0126] 20, 20A: Cathode electrodes;

[0127] 29C, 29L: Cathode through-holes;

[0128] 30: Second partition wall;

[0129] 30L: Partition wall adjustment part;

[0130] 30P: Inner peripheral part;

[0131] 40: Adhesive;

[0132] 50: Insulating resin;

[0133] 61, 62: External electrodes;

[0134] 100: Capacitor element laminate;

[0135] 131: Inner layer CP;

[0136] 132: Outer layer CP;

[0137] 210: Third partition wall.

Claims

1. A solid electrolytic capacitor, characterized in that, Comprising: A sheet laminate formed by alternately laminating a plurality of flat film-shaped capacitor elements and a plurality of flat film-shaped cathode electrode foils with a conductive adhesive interposed therebetween; and An insulating resin for sealing the sheet laminate, The flat film-shaped capacitor element comprising: A flat film-shaped anode electrode foil; A dielectric layer formed on the surface of the anode electrode foil; A first partition wall formed on the surface of the dielectric layer; And A solid electrolyte layer formed in a region defined by the first partition wall, The conductive adhesive is formed in a region defined by a second partition wall that at least overlaps with the first partition wall, The second partition wall is formed to cover a boundary portion between the solid electrolyte layer and the first partition wall.

2. The solid electrolytic capacitor according to claim 1, wherein The second partition wall has a partition adjustment portion where the partition wall material is not formed.

3. The solid electrolytic capacitor according to claim 2, wherein The size of the partition adjustment portion is determined according to the volume of the second partition wall.

Images