WO2023188555A1

WO2023188555A1 - Solid electrolytic capacitor, and method for manufacturing solid electrolytic capacitor

Info

Publication number: WO2023188555A1
Application number: PCT/JP2022/045256
Authority: WO
Inventors: 純一佐藤; 健一鴛海; 和豊堀尾
Original assignee: 株式会社村田製作所
Priority date: 2022-03-30
Filing date: 2022-12-08
Publication date: 2023-10-05

Abstract

A solid electrolytic capacitor according to the present invention comprises: 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 that seals the sheet laminate. Each of the flat film-shaped capacitor elements comprises: a flat film-shaped anode electrode foil; a dielectric layer formed on the surface of the anode electrode foil; a first dam formed on the surface of the dielectric layer; and a solid electrolyte layer formed within a region regulated by the first dam. The conductive adhesive is formed within a region regulated by a second dam overlapping at least the first dam. The second dam is formed so as to cover a boundary section between the solid electrolyte layer and the first dam.

Description

Solid electrolytic capacitor and method for manufacturing solid electrolytic capacitor

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.

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 (cathode). A flat film capacitor element includes a foil-like valve metal base, a porous portion and a dielectric layer formed on the surface of the valve metal base, and a solid electrolyte layer formed on the surface of the dielectric layer.

More specifically, it has the following configuration. A mask layer is formed on the surface of the dielectric layer in Patent Document 1 to cover the ends and sides of each element region. A solid electrolyte layer is formed in a region surrounded by this mask layer. Furthermore, an insulating adhesive layer is formed so as to overlap this mask layer, and a conductive layer is formed on this solid electrolyte layer.

The flat film-shaped capacitor elements and metal foils thus formed are alternately laminated, thereby forming an element laminate. The element stack is sealed with an insulating resin.

Patent Document 2 describes a surface-mount thin capacitor. The cathode portion of the surface-mount 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. An insulating resin is formed so as to partially cover this resist resin.

JP2019-79866A Japanese Patent Application Publication No. 2009-129936

However, in a solid electrolytic capacitor as shown in Patent Document 1, when a flat film capacitor element and a valve metal base (metal foil) having a dielectric layer formed on the surface are laminated, the conductor layer wets and spreads. At this time, if a gap exists at the boundary between the mask layer and the solid electrolyte layer, the dielectric layer may be exposed. Furthermore, even if 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 may be separated by heat and pressure treatment during subsequent lamination, etc. Layers may shrink. That is, there is a possibility that the boundary between the mask layer and the solid electrolyte layer will be exposed, and the conductor layer and the valve metal base will come into contact with each other. This increases leakage current and may cause a short circuit.

On the other hand, in the surface mount 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 formed at the boundary between the anode and cathode parts. However, since the insulating resin only covers a part of the resist resin, when re-forming is performed, the resist resin and conductive polymer will shrink, and the chemical solution will flow between the resist resin and the conductive polymer. Get into it. This creates a gap between the resist resin and the conductive polymer. Therefore, the configuration of Patent Document 2 may also cause the same problem as Patent Document 1.

Therefore, an object of the present invention is to provide a solid electrolytic capacitor that can suppress short circuits between an anode and a cathode and achieve high reliability.

The solid electrolytic capacitor of the present invention includes a sheet laminate formed by alternately laminating a plurality of flat film capacitor elements and a plurality of flat film cathode electrode foils via a conductive adhesive; and an insulating resin that seals the laminate. A flat film capacitor element includes a flat film-like anode electrode foil, a dielectric layer formed on the surface of the anode electrode foil, a first dam formed on the surface of the dielectric layer, and a first dam. A solid electrolyte layer formed within a region regulated by. The conductive adhesive is formed within a region regulated by the second dam that overlaps at least the first dam. The second dam is formed to cover the boundary between the solid electrolyte layer and the first dam.

With this configuration, even when the capacitor element and the cathode electrode foil are laminated using a conductive adhesive, it is possible to suppress the conductive adhesive from coming into contact with the solid electrolyte layer. That is, short circuit between the anode and the cathode is suppressed.

FIG. 1 is a side sectional view showing the configuration of a solid electrolytic capacitor according to a first embodiment. FIG. 2(A) is a side cross-sectional view showing the configuration of a set of a capacitor element and a cathode electrode before singulation, and FIG. 2(B) is a side cross-sectional view showing the configuration of the capacitor element before singulation. FIG. 2C is a side cross-sectional view showing the configuration of a set of a capacitor element and a cathode electrode after being separated into pieces. FIG. 3(A) is a diagram schematically showing the structure of the capacitor element and cathode electrode of the present invention, and FIG. 3(B) is a diagram schematically showing the structure of the capacitor element and cathode electrode of the conventional configuration. FIG. FIG. 4(A) is a plan view schematically showing the structure of the capacitor element and cathode electrode of the present invention, and FIG. 4(B) is a plan view schematically showing the structure of the capacitor element and cathode electrode of the conventional configuration. FIG. FIG. 5 is a flowchart showing an example of a schematic flow of the method for manufacturing a solid electrolytic capacitor according to the present embodiment. FIG. 6 is a flowchart showing an example of a process for forming a capacitor element sheet. FIG. 7(A) is an external perspective view showing the shape of the anode electrode and dielectric layer of the capacitor element before singulation, and FIG. 7(B) is an external appearance showing the shape of the capacitor element before singulation. FIG. FIG. 8 is an external view in the multi-state. FIG. 9 is an external perspective view showing the shape of the cathode electrode before singulation. FIG. 10 is a flowchart illustrating an example of a process for forming a sheet laminate. FIGS. 11(A) and 11(B) are external perspective views showing a state in which a second dam is formed on the capacitor element sheet. 12(A) and 12(B) are external perspective views showing a state in which a second dam and an adhesive are formed on a capacitor element sheet. 13(A) and 13(B) are exploded perspective views showing a state in which a capacitor element sheet and a cathode electrode sheet are laminated. FIG. 14(A) is an exploded perspective view showing a laminated state of a capacitor element sheet and a cathode electrode sheet in a multi-state, and FIG. 14(B) is an exploded perspective view showing a laminated state of a capacitor element sheet and a cathode electrode sheet in a multi-state. FIG. 3 is an external perspective view showing a stacked state. FIG. 15 is an exploded perspective view showing the state of the capacitor element sheet and the cathode electrode sheet in a multi-state state. FIG. 16(A) is a side cross-sectional view showing the configuration of a set of a capacitor element and a cathode electrode before singulation in the second embodiment, and FIG. FIG.

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

(Explanation of the schematic configuration of solid electrolytic capacitor 1)
First, the structure of a solid electrolytic capacitor according to an embodiment of the present invention will be described. FIG. 1 is a side 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 the external electrodes are hatched to make the diagram easier to read. FIG. 2(A) is a side sectional view showing the configuration of a set of a capacitor element and a cathode electrode before being separated into pieces. FIG. 2(B) is a side cross-sectional view showing the structure of the capacitor element before being separated into pieces. FIG. 2(C) is a side sectional view showing the configuration of a set of a capacitor element and a cathode electrode after being separated into pieces.

As shown in FIGS. 1, 2(A), 2(B), and 2(C), 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-shaped capacitor elements 10 , a plurality of flat film-shaped cathode electrodes 20 , a second dam 30 , and an adhesive 40 . In FIG. 1, the number of flat film capacitor elements 10 and the number of cathode electrodes is four, but the number is not limited to this. Note that the cathode electrode 20 corresponds to the "cathode electrode foil" in the present invention. The side sectional views in FIGS. 1, 2(A), 2(B), and 2(C) are sectional views taken along a plane perpendicular to the top surface 101 and bottom surface 102 of the capacitor element laminate 100 in FIG. .

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

Although the detailed structure is not illustrated in FIG. 2, the anode electrode 11 includes a large number of holes. In other words, the anode electrode 11 is in a porous state (porous body). The ratio of the thicknesses of the porous portion and core metal portion on one side of the anode electrode 11 to the porous portion on the other side is approximately 1:1:1. Dielectric layer 12 covers the outer surface of anode electrode 11 . Since the detailed structure of the anode electrode 11 is not shown in FIG. 2, the dielectric layer 12 is schematically shown 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 surfaces of many holes in the anode electrode 11 . Note that the anode electrode 11 corresponds to the "anode electrode foil" in the present invention.

The CP layer 13 covers the surface of the dielectric layer 12. The CP layer 13 is formed inside a frame-shaped first dam 14. The first dam 14 has insulation properties. The region in which the CP layer 13 is formed is regulated by the first dam 14 . Note that in the first embodiment, as explained in the manufacturing method described later, after the first dam 14 is formed into a frame shape, the CP layer 13 is formed inside the first dam 14. However, depending on the manufacturing method of the capacitor element 10, for example, when the capacitor element 10 is created in a singulated state from the beginning, the first dam 14 may not be formed in a frame shape. That is, the first dam 14 may be formed on one side, or may be formed on two sides having corners. Furthermore, the structure may be formed on two opposing sides in a plan view.

The CP layer 13 has a laminated structure of an inner layer CP (inner solid electrolyte layer) 131 and an outer layer CP (outer solid electrolyte layer) 132. The inner layer CP131 is formed on the surface of the dielectric layer 12, and the outer layer CP132 is formed on the surface of the inner layer CP131.

The plurality of capacitor elements 10 and the plurality of cathode electrodes 20 are alternately stacked so that their flat film surfaces are parallel and overlap in plan view.

A second dam 30 and an adhesive 40 are provided between adjacent capacitor elements 10 and cathode electrodes 20. The second dam 30 has insulation properties. Adhesive 40 has electrical conductivity. Note that the adhesive 40 corresponds to the "conductive adhesive" in the present invention.

The second dam 30 has a frame shape. The adhesive 40 is placed inside the frame defined by the second dam 30. Adjacent capacitor elements 10 and cathode electrodes 20 are bonded together by this adhesive 40 .

As shown in FIG. 2(B), the second dam 30 is formed to overlap the outer layer CP 132. In other words, it is formed to cover the end of the first dam 14 and the end of the outer layer CP132. A more detailed structure will be described later. Note that the second dam 30 is made of an insulating material such as an insulating resin, for example.

The second dam 30 has a dam adjustment section 30L. This dam adjustment section 30L is used to control the volume when applying the second dam 30. In other words, by using the dam adjustment section 30L, unnecessary expansion of the second dam 30 during stacking is suppressed. By unnecessarily expanding the second dam 30, the second dam 30 enters, for example, the anode through

holes

19C and 19L and the cathode through

holes

29C and 29L (detailed configurations of which are shown below). However, by having the dam adjustment portion 30L, it is possible to inhibit molding by the insulating resin 50 and prevent molding defects from occurring.

The dam adjustment section 30L is formed by a printed pattern. The dam adjustment portion 30L may be a through hole or may have a shape having a bottom surface on the second dam 30 like a recessed portion. Further, it is preferable to form the size (width, length) of the dam adjustment portion 30L according to the volume of the second dam 30.

Note that the second dam 30 is expanded by heating and pressurizing the capacitor element 10 and the cathode electrode 20. This reduces the difference in thickness between the dam adjustment portion 30L and other portions.

In such a stacked state, the first ends 10E1 (see FIG. 2C) of the plurality of capacitor elements 10 are at approximately the same position when viewed from the side. Similarly, the second ends 10E2 (see FIG. 2C) of the plurality of capacitor elements 10 are at substantially the same position when viewed from the side. Furthermore, the first ends 20E1 (see FIG. 2C) of the plurality of cathode electrodes 20 are at substantially the same position when viewed from the side. Similarly, the second ends 20E2 (see FIG. 2C) of the plurality of cathode electrodes 20 are at substantially the same position when viewed from the side.

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 stack 100. The first ends 10E1 of the plurality of capacitor elements 10 protrude further outward than the second ends 20E2 of the plurality of cathode electrodes 20.

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 stack 100. The first ends 20E1 of the plurality of cathode electrodes 20 protrude further outward than the second ends 10E2 of the plurality of capacitor elements 10.

With such a structure, the capacitor element stack 100 is realized.

The capacitor element stack 100 is sealed with an insulating resin 50. More specifically, the insulating resin 50 is applied to the capacitor element laminate 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. Cover 100.

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 end 10E1 of the anode electrode 11 of the plurality of capacitor elements 10.

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 end 20E1 of the plurality of cathode electrodes 20.

With the above configuration, the solid electrolytic capacitor 1 is realized.

(Detailed structure description of solid electrolytic capacitor 1)
Next, the detailed structure of the capacitor element 10 and the cathode electrode 20 that constitute the solid electrolytic capacitor 1 will be described using FIGS. 3(A) and 3(B). FIG. 3(A) is a side sectional view schematically showing the structure of the capacitor element 10 and the cathode electrode 20, and is an enlarged view of the structure of FIG. 2(A) described above. FIG. 3(B) is a side sectional view schematically showing the structure of the capacitor element 10 and the cathode electrode 20 according to the conventional structure. In FIGS. 3(A) and 3(B), the structure of one main surface of the capacitor element 10 on which the cathode electrode 20 is disposed will be explained, but the same structure can be applied to the other main surface opposite to the one main surface. It is a structure. The side cross-sectional views in FIGS. 3A and 3B 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 FIG.

In addition, each structure is enlarged and exaggerated to make the explanation easier to understand. Although FIGS. 3A and 3B show only one set of the capacitor element 10 and the cathode electrode 20, the solid electrolytic capacitor 1 is formed by laminating a plurality of these sets.

As shown in FIG. 3(A), an outer layer CP 132 is formed within the region surrounded by the first dam 14. A boundary portion BD exists at the boundary between the inside of the area formed by the first dam 14 and the area where the outer layer CP132 is formed. Due to the existence of this boundary portion BD, the dielectric layer 12 is exposed. For convenience, the boundary portion BD and the exposed portion of the dielectric layer 12 are shown as the same portion.

However, in the present invention, the second dam 30 is formed to cover this boundary portion BD. That is, even if the dielectric layer 12 is exposed, the second dam 30 enters the exposed portion. Therefore, the dielectric layer 12 is not exposed.

By laminating the capacitor element 10 with this configuration and the plurality of cathode electrodes 20 via the adhesive 40, contact between the adhesive 40 and the anode electrode 11 can be suppressed. That is, short circuit between the anode and the cathode is suppressed.

Next, a more detailed configuration will be described using FIG. 3(A), FIG. 4(A), and FIG. 4(B). FIG. 4(A) is a plan view schematically showing the arrangement of the adhesive 40 on the capacitor element 10. FIG. 4(B) is a plan view schematically showing the arrangement of the adhesive 40 on the capacitor element 10 in a conventional configuration. Note that in FIGS. 4(A) and 4(B), in order to explain the dielectric layer 12 in an easy-to-understand manner, the hatching is different from that in other figures, and each structure is The composition is expanded and exaggerated.

As shown in FIGS. 3(A) and 4(A), the positional relationship between the inner circumferential portion 14P of the first dam 14 and the inner circumferential portion 30P of the second dam 30 is compared. In the present invention, the inner peripheral part 30P is formed inside the capacitor element 10 (inner side in plan view) at a distance d from the inner peripheral part 14P over the entire circumference. That is, the second dam 30 is formed to extend further into the capacitor element 10 than the first dam 14 at the distance d. Note that the distance d is preferably in a range of about 50 μm to about 100 μm.

With this configuration, the boundary portion BD is covered by the second dam 30. That is, even if the adhesive 40 wets and spreads through a process such as heating and pressing, the adhesive 40 does not come into contact with the dielectric layer 12 (boundary portion BD). That is, short circuit between the anode electrode 11 and the cathode electrode 20 can be suppressed.

(Method for manufacturing solid electrolytic capacitor 1)
The solid electrolytic capacitor 1 having the above-described configuration is manufactured, for example, as follows. FIG. 5 is a flowchart showing an example of a schematic flow of the method for manufacturing a solid electrolytic capacitor according to the present embodiment.

A capacitor element sheet is formed (FIG. 5: S11). A plurality of capacitor elements 10 forming different solid electrolytic capacitors 1 are arranged on the capacitor element sheet.

Next, the capacitor element sheet and the cathode electrode sheet are laminated with the adhesive 40 in between to form a sheet laminate (FIG. 5: S12). Note that a plurality of cathode electrodes 20 forming different solid electrolytic capacitors 1 are arranged in the cathode electrode sheet. As a result, 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 one in which a plurality of capacitor element laminates 100 are arranged in a plane.

Next, the sheet stack is sealed with insulating resin 50 (FIG. 5: S13). Although details will be described later, at this time, a through hole penetrating from the upper surface to the lower surface of the sheet laminate is provided in the sheet laminate, and resin sealing is performed by compression molding.

This sealing with the insulating resin 50 is performed in a multi-state state (a state in which a plurality of solid electrolytic capacitors 1 are arranged) before the solid electrolytic capacitors 1 are separated into individual pieces.

Next, the sheet stack sealed with the insulating resin 50 is cut into individual pieces (FIG. 5: S14). Specifically, cutting is performed along cutting lines E11, E12, S11, and S12 shown in FIG. 13(B), which will be described later. As a result, a plurality of solid electrolytic capacitors 1 (referred to as elements of solid electrolytic capacitors 1) in which no external electrodes are formed are formed. Thereafter, the element body of the solid electrolytic capacitor 1 is subjected to secondary sealing with an insulating resin 50. More specifically, the side surface of the element body of the solid electrolytic capacitor 1 (the surface cut along the cutting lines S11 and S12 (the top surface, the bottom surface, the side surface different from the end surface where the anode electrode 11 and the cathode electrode 20 are exposed)) is insulated. It is covered by secondary sealing with a synthetic resin 50. Thereby, the anode electrode 11 and the cathode electrode 20 that are unnecessarily exposed during singulation are covered with the insulating resin 50.

Next,

external electrodes

61 and 62 are formed on the end face of the element body of solid electrolytic capacitor 1 (FIG. 5: S15).

Next, each step will be explained in more detail.

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

A chemical conversion treatment is performed on the anode electrode 11 to form the dielectric layer 12 (FIG. 6: S111). At this time, a large number of holes are formed on the surface of the anode electrode 11 by etching, and the vicinity of the surface of the anode electrode 11 is a porous body. The dielectric layer 12 covers the surface of the anode electrode 11 including the inner surface of the hole.

Next, an anode through hole is formed in the anode electrode 11 (FIG. 6: S112). More specifically, as shown in FIG. 7A, a plurality of cylindrical anode through holes 19C and groove-shaped anode through holes 19L are formed in the anode electrode 11. The plurality of cylindrical anode through-holes 19C and the groove-shaped anode through-holes 19L are arranged alternately along the direction in which the portions that will become the plurality of anode electrodes 11 are lined up. The plurality of cylindrical anode through holes 19C are formed at positions that realize the first ends 10E1 of the anode electrodes 11, and the groove-shaped anode through holes 19L are formed at positions that straddle the portions that will become adjacent anode electrodes 11. And, it is formed at a position that realizes the second end 10E2 of the adjacent anode electrodes 11.

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

As shown in FIG. 8, this structure has a multi-state structure in which a plurality of capacitor elements 10 (a structure consisting of an anode electrode 11, a dielectric layer 12, a CP layer 13, and a first dam 14) are arranged in two dimensions. It will be held in

(Cathode electrode sheet formation process)
FIG. 9 is an external perspective view showing the shape of the cathode electrode before singulation.

As shown in FIG. 9, the cathode electrode 20 is formed with a plurality of cylindrical cathode through holes 29C and groove-shaped cathode through holes 29L. The plurality of cylindrical cathode through-holes 29C and the groove-shaped cathode through-holes 29L are arranged alternately along the direction in which the portions that will become the plurality of cathode electrodes 20 are lined up. The plurality of cylindrical cathode through holes 29C are formed at positions that realize the first ends 20E1 of the cathode electrodes 20, and the groove-shaped cathode through holes 29L are formed at positions that straddle the portions that will become adjacent cathode electrodes 20, And, it is formed at a position that realizes the second end 20E2 of the adjacent cathode electrodes 20.

(Formation process of sheet laminate)
FIG. 10 is a flowchart illustrating an example of a process for forming a sheet laminate. FIG. 11 is an external perspective view showing a state in which a second dam is formed on a capacitor element sheet, FIG. 11(A) shows a multi-state state, and FIG. 11(B) shows a portion of one capacitor element. FIG. 12 is an external perspective view showing a state in which a second dam and adhesive are formed on a capacitor element sheet, FIG. 12(A) shows a multi-layer state, and FIG. 12(B) shows a portion of one capacitor element. shows. 13(A) and 13(B) are exploded perspective views showing a state in which a capacitor element sheet and a cathode electrode sheet are laminated. 13(A) and 13(B) show portions corresponding to one solid electrolytic capacitor. FIG. 14(A) is an exploded perspective view showing a laminated state of a capacitor element sheet and a cathode electrode sheet in a multi-state, and FIG. 14(B) is an exploded perspective view showing a laminated state of a capacitor element sheet and a cathode electrode sheet in a multi-state. FIG. 3 is an external perspective view showing a stacked state. FIG. 15 is a diagram showing the structure after laminating a capacitor element sheet and a cathode electrode sheet and heating and pressurizing them.

A second dam 30 is formed on the sheet stack (FIG. 10: S121). More specifically, as shown in FIGS. 11(A) and 11(B), a second dam 30 having a frame-shaped opening is formed. The second dam 30 is formed at a position overlapping the first dam 14. Furthermore, the second dam 30 is formed to an area inside the inner frame of the first dam 14. However, the shape at the time of printing is not limited to this, as long as the second dam 30 has a shape that expands further inward than the inner frame of the first dam 14 during heating and pressurization, which will be described later.

At this time, the second dam 30 is formed by a printed pattern so as to have a dam adjustment portion 30L. In addition, in FIG. 11(A), the example in which the dam adjustment part 30L is formed in the whole 1st dam 14 was shown. However, a configuration may be adopted in which the dam adjustment portion 30L is not formed over the entire first dam 14. That is, the number of dam adjustment parts 30L may be formed according to the volume of the adhesive 40, similar to the size of the dam adjustment parts 30L described above.

Next, as shown in FIGS. 12(A) and 12(B), the adhesive 40 is placed inside the opening of the second dam 30 (FIG. 10: S122).

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

- When viewed in the stacking direction, the plurality of cylindrical anode through holes 19C in the capacitor element sheet and the groove-shaped cathode through holes 29L in the cathode electrode sheet overlap.
- When viewed in the stacking direction, the groove-shaped anode through-hole 19L in the capacitor element sheet overlaps 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-hole 19L in the capacitor element sheet and the groove-shaped cathode through-hole 29L in the cathode electrode sheet overlap.
A plurality of these through holes are formed in accordance with the number of capacitor elements arranged in the sheet laminate. Therefore, a plurality of through holes are formed in the sheet stack, which penetrate from the top surface to the bottom surface of the sheet stack.

Next, the sheet laminate is heated and pressurized (FIG. 10: S124). Thereby, the capacitor element sheet and the cathode electrode sheet are adhered by the adhesive 40, and a sheet laminate is formed. As shown in FIG. 15, this heating and pressing causes the adhesive 40 to spread in a plane. However, since the second dam 30 covers the boundary portion BD, contact between the adhesive 40 and the anode electrode 11 can be suppressed. That is, short circuit between the anode and the cathode is suppressed.

Also, due to this heating and pressurization, the dam adjustment portion 30L formed in the second dam 30 is closed. Thereby, the thickness of the second dam 30 can be adjusted, and the thickness of the second dam 30 can be prevented from becoming unnecessarily high. Therefore, the height of the sheet laminate can be reduced.

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

As shown in FIGS. 16(A) and 16(B), the solid electrolytic capacitor 1A according to the second embodiment has a third electrode on the cathode electrode 20A, unlike the solid electrolytic capacitor 1 according to the first embodiment. The difference is that a dam 210 is included. The other configuration of the solid electrolytic capacitor 1A is the same as that of the solid electrolytic capacitor 1, and the explanation of the similar parts will be omitted.

As shown in FIG. 16(B), the cathode electrode 20A includes a third dam 210. The third dam 210, like the second dam 30, is made of an insulating material such as an insulating resin.

The cathode electrode 20A and the capacitor element 10 are bonded together through the adhesive 40 by heating and pressurizing. Even with such a configuration, contact between the adhesive 40 and the anode electrode 11 can be suppressed. The presence of the third dam 210 can further suppress the spread of the adhesive 40 from the cathode electrode 20A to the outer periphery.

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

The anode electrode 11 is made of, for example, a single metal such as aluminum, tantalum, niobium, titanium, zirconium, or magnesium, or an alloy containing these metals. Note that the anode electrode 11 is preferably made of aluminum or an aluminum alloy. The anode electrode 11 may be any valve metal as long as it exhibits a so-called valve action.

It is preferable that the anode electrode 11 has a flat plate shape, and the thickness of the core part of the anode electrode 11 (the central part where the pores of the porous body do not reach) is preferably 5 μm or more and 100 μm or less. The thickness (thickness of one side) of the porous portion (the portion of the porous body in which pores are formed) is preferably 5 μm or more and 200 μm or less.

The dielectric layer 12 is preferably made 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 or ammonium salts. The thickness of the dielectric layer 12 is preferably 1 nm or more and 100 nm or less.

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

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.

The adhesive 40 is preferably a mixture of an insulating resin such as an epoxy resin or a phenol resin, and conductive particles such as carbon or silver. Note that the adhesive 40 may be a dispersion of a conductive polymer, a dispersion of a conductive polymer to which a binder is added, or the like.

The cathode electrode 20 is made of, for example, aluminum, titanium, copper, silver, or the like. The thickness of the cathode electrode 20 is, for example, thinner than or approximately the same as the thickness of the anode electrode 11. Note that the thickness of the cathode electrode 20 is preferably as thin as possible, and is about 5 μm to 50 μm, preferably about 30 μm.

Insulating resin 50 may contain filler. Preferred examples of the resin include epoxy resins, phenol resins, polyimide resins, silicone resins, polyamide resins, and liquid crystal polymers. As the filler, for example, insulating oxide particles such as silica particles, alumina particles, titania particles, and zirconia particles are preferable. The maximum diameter of the filler is preferably 30 μm or more and 40 μm or less, for example. For example, it is more preferable to use a material containing silica particles in solid epoxy resin and phenol resin.

BD...boundary part d...distance 1, 1A...solid electrolytic capacitor 10...capacitor element 10E1, 20E1...first end 10E2, 20E2...second end 11...anode electrode 12...dielectric layer 14...first dam 14P...

inner circumference Parts

19C, 19L...Anode through

holes

20, 20A...

Cathode electrodes

29C, 29L...Cathode through holes 30...Second dam 30L...Dam adjustment part 30P...Inner peripheral part 40...Adhesive 50...Insulating

resin

61, 62 …External electrode 100…Capacitor element laminate 131…Inner layer CP
132...Outer layer CP
210...Third dam

Claims

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 via a conductive adhesive;
an insulating resin that seals the sheet laminate;
Equipped with
The flat film capacitor element is
A flat film-shaped anode electrode foil,
a dielectric layer formed on the surface of the anode electrode foil;
a first dam formed on the surface of the dielectric layer;
a solid electrolyte layer formed within a region regulated by the first dam;
Equipped with
The conductive adhesive is formed at least within a region regulated by a second dam overlapping the first dam,
The second dam is a solid electrolytic capacitor formed to cover a boundary between the solid electrolyte layer and the first dam.
The solid electrolytic capacitor according to claim 1, wherein the second dam has a dam adjustment portion in which no dam material is formed.
The size of the dam adjustment part is determined according to the volume of the second dam.
The solid electrolytic capacitor according to claim 2.
a step of forming a plurality of flat film capacitor elements;
a step of forming a plurality of flat film-like cathode electrode foils;
forming a sheet laminate by alternately laminating the plurality of flat film capacitor elements and the plurality of flat film cathode electrode foils via a conductive adhesive;
a step of sealing the sheet laminate with an insulating resin;
has
The step of forming the flat film-like capacitor element includes:
a step of forming a dielectric layer on the surface of a flat film-shaped anode electrode foil;
forming a first dam on the surface of the dielectric layer;
forming a solid electrolyte layer within a region regulated by the first dam;
has
The step of forming the sheet laminate includes:
forming a second dam that overlaps at least the first dam;
forming the conductive adhesive within a region regulated by the second dam;
has
the second dam is formed to cover a boundary between the solid electrolyte layer and the first dam;
Method of manufacturing solid electrolytic capacitors.
In the step of forming the sheet laminate,
5. The method for manufacturing a solid electrolytic capacitor according to claim 4, wherein the second dam includes a dam adjustment portion in which no dam material is formed.