WO2023153432A1

WO2023153432A1 - Electrolytic capacitor element

Info

Publication number: WO2023153432A1
Application number: PCT/JP2023/004164
Authority: WO
Inventors: 啓史吉田; 泰央田中
Original assignee: 株式会社村田製作所
Priority date: 2022-02-14
Filing date: 2023-02-08
Publication date: 2023-08-17

Abstract

An electrolytic capacitor element 1 comprises: a positive electrode 10 that is formed from a valve-action metal substrate 11, and has a leading end surface 10a and a base end surface 10b; a dielectric layer 20 provided on at least one of main surfaces 10c, 10d of the positive electrode 10, excluding at least the base end surface 10b; a mask layer 30 formed from an insulating material and provided on the dielectric layer 20 along the base end surface 10b; and a negative electrode 40 provided on the dielectric layer 20 farther on the leading end surface 10a side as compared to the mask layer 30. The negative electrode 40 has a solid electrolyte layer 50 provided on the dielectric layer 20, and an electroconductive layer 60 provided on the solid electrolyte layer 50. The solid electrolyte layer 50 includes a first layer 51 containing a first electroconductive polymer and provided on the dielectric layer 20, a second layer 52 containing a second electroconductive polymer and a binder component, and a third layer 53 containing a third electroconductive polymer and provided on at least the first layer 51. The second layer 52 is disposed partially within the plane of the solid electrolyte layer 50, and the first layer 51 and the third layer 53 are disposed at least in a region where the second layer 52 is not disposed within the plane of the solid electrolyte 50.

Description

electrolytic capacitor element

The present invention relates to electrolytic capacitor elements.

Patent Document 1 discloses, as a solid electrolytic capacitor with low equivalent series resistance (ESR) and leakage current, an anode body made of a valve action metal, a dielectric oxide film formed on the surface of the anode body, and a solid electrolyte on the dielectric oxide film. In a solid electrolytic capacitor having a layer and a cathode current collector layer on the solid electrolyte layer, the solid electrolyte layer is dielectric from a solution or dispersion containing a conductive polymer selected from the group consisting of polyaniline, polypyrrole and derivatives thereof. a first solid electrolyte layer formed on the solid oxide film; and a second solid layer formed on the first solid electrolyte layer from a solution or dispersion containing a conductive polymer selected from the group consisting of polythiophene and derivatives thereof. a second solid electrolyte from a solution or dispersion containing an electrolyte layer and a conductive polymer selected from the group consisting of polythiophene and derivatives thereof, and having a composition different from that of the solution or dispersion used for forming the second solid electrolyte layer; A solid electrolytic capacitor is disclosed having a third solid electrolyte layer formed on the layer.

In Patent Document 2, a solid electrolytic capacitor having an anode body made of a valve action metal foil having a porous expanded surface in order to reduce the defect rate due to leakage current, a second solid electrolyte is added to the capacitor element. Forming an insulating resin layer between the second solid electrolyte layer and the graphite layer so as to extend from the side surface of the layer and cover at least a part of the outer edge of the planar portion of the second solid electrolyte layer. is disclosed.

JP 2011-253878 A JP 2012-134389 A

In Patent Document 1, a polyaniline- or polypyrrole-based conductive polymer is used for the first solid electrolyte layer, and a polythiophene-based conductive polymer is used for the second solid electrolyte layer and the third solid electrolyte layer. However, the first solid electrolyte layer and the second solid electrolyte layer are made of different materials, and there is room for improvement in that the equivalent series resistance (ESR) increases due to an increase in interfacial resistance due to poor adhesion between these layers. be. In addition, it is also possible to use a dispersion containing an insulating binder (polyvinyl alcohol, see paragraph [0030]) for each layer. There is room for improvement in this respect as well.

In Patent Document 2, since the side surface (corner) of the element, which is easily damaged by molding stress during molding, is partially covered with an insulator, electrical responsiveness is maintained between the solid electrolyte layer, the graphite layer, and the silver paste layer. There is room for improvement in that the ESR is increased due to the worsening of the ESR (path becomes longer). In addition, since different materials are exposed when forming the graphite layer, the wettability of the surface is not constant, a uniform coating cannot be formed, and the ESR characteristics vary.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an electrolytic capacitor element capable of suppressing leakage current while suppressing an increase in equivalent series resistance.

In a first aspect of the electrolytic capacitor element of the present invention, an anode is composed of a valve metal substrate and has a distal end surface and a proximal end surface; a mask layer made of an insulating material and provided on the dielectric layer along the proximal face; and a mask layer provided on the dielectric layer on the distal face side of the mask layer. a cathode, the cathode having a solid electrolyte layer provided on the dielectric layer; and a conductive layer provided on the solid electrolyte layer, the solid electrolyte layer comprising the dielectric a first layer provided on the body layer and containing a first conductive polymer; a second layer containing a second conductive polymer and a binder component; and a third layer containing a conductive polymer, wherein the second layer is partially arranged in the plane of the solid electrolyte layer, and the first layer and the third layer are composed of the solid It is arranged at least in a region where the second layer is not arranged in the plane of the electrolyte layer.

In the second aspect of the electrolytic capacitor element of the present invention, the anode is composed of a valve metal substrate and has a distal end surface and a proximal end surface, and at least one main surface of the anode except for the proximal end surface is provided on at least one main surface. a mask layer made of an insulating material and provided on the dielectric layer along the proximal face; and a mask layer provided on the dielectric layer on the distal face side of the mask layer. a cathode, the cathode having a solid electrolyte layer provided on the dielectric layer; and a conductive layer provided on the solid electrolyte layer, the solid electrolyte layer comprising the dielectric A first layer provided on the body layer and containing a first conductive polymer, a second layer containing a second conductive polymer, and a third conductive layer provided on at least the first layer a third layer containing a polymer, wherein the second layer is partially arranged in the plane of the solid electrolyte layer, and the first layer and the third layer are formed on the solid electrolyte layer. It is arranged at least in a region where the second layer is not arranged in the plane, and the second layer is a denser film than the first layer and the third layer.

According to the present invention, it is possible to provide an electrolytic capacitor element capable of suppressing leakage current while suppressing an increase in equivalent series resistance.

FIG. 1 is a plan view schematically showing an example of an electrolytic capacitor element according to an embodiment of the invention. FIG. 2 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 1 along line XX. 3 is a perspective view of the electrolytic capacitor element shown in FIG. 1. FIG. 4 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 3 along line AA. FIG. 5 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 3 along line BB. FIG. 6 is a perspective view schematically showing an example of an electrolytic capacitor element according to another embodiment of the invention. 7 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 6 along line CC. 8 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 6 taken along line DD. FIG. 9 is a perspective view schematically showing an example of an electrolytic capacitor element according to still another embodiment of the invention. 10 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 9 taken along line EE. 11 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 9 taken along line FF. FIG. 12 is a perspective view schematically showing an example of an electrolytic capacitor element according to still another embodiment of the invention. 13 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 12 along line GG. 14 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 12 taken along line HH. 15 is an enlarged cross-sectional view of the mask layer portion of the electrolytic capacitor element shown in FIG. 2. FIG. FIG. 16 is a schematic diagram showing an example of a process of preparing a valve metal substrate on which a mask layer is formed. FIG. 17 is a schematic diagram showing an example of the process of forming the first layer and the third layer of the solid electrolyte layer. FIG. 18 is a schematic diagram showing an example of the process of forming the second layer of the solid electrolyte layer. FIG. 19 is a perspective view schematically showing an example of an electrolytic capacitor including an electrolytic capacitor element according to an embodiment of the invention. 20 is a cross-sectional view of the electrolytic capacitor shown in FIG. 19 taken along line ZZ. 21 shows a SEM photograph of a cross section of the electrolytic capacitor of Example 1. FIG.

The electrolytic capacitor element of the present invention will be described below.
However, the present invention is not limited to the following configurations, and can be appropriately modified and applied without changing the gist of the present invention. Combinations of two or more of the individual desirable configurations described below are also part of the present invention.

Also, each embodiment shown below is an example, and it goes without saying that partial replacement or combination of configurations shown in different embodiments is possible. Descriptions of items common to multiple embodiments will be omitted, and only different points will be described.

[Electrolytic capacitor element]
FIG. 1 is a plan view schematically showing an example of an electrolytic capacitor element according to an embodiment of the invention. FIG. 2 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 1 along line XX. Note that in FIG. 1, the solid electrolyte layer 50 covered with the conductive layer 60 is indicated by a dashed line. 1 and 2 show the solid electrolyte layer 50 without distinguishing between the first layer 51, the second layer 52 and the third layer 53. FIG.

The electrolytic capacitor element 1 shown in FIGS. 1 and 2 is a solid electrolytic capacitor element, which is composed of a valve action metal substrate 11, an anode 10 having a distal end surface 10a and a proximal end surface 10b, and an anode 10 except for the proximal end surface 10b. a dielectric layer 20 provided on the surface of the dielectric layer 20, a mask layer 30 made of an insulating material and provided on the dielectric layer 20 along the base end face 10b, and a dielectric layer 30 on the tip face 10a side of the mask layer 30 a cathode 40 provided on the body layer 20, the cathode 40 comprising a solid electrolyte layer 50 provided on the dielectric layer 20; a conductive layer 60 provided on the solid electrolyte layer 50; have.

FIG. 3 is a perspective view of the electrolytic capacitor element shown in FIG. 4 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 3 along line AA. FIG. 5 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 3 along line BB. 3, 4 and 5 show the state before the conductive layer 60 of the cathode 40 is formed. In addition, FIG. 3 omits illustration of the dielectric layer 20 and shows a state in which the members inside the third layer 53 of the solid electrolyte layer 50 are seen through.

As shown in FIGS. 3, 4 and 5, the solid electrolyte layer 50 is provided on the dielectric layer 20 and comprises a first layer 51 containing a first conductive polymer and a second conductive polymer. and a second layer 52 containing a binder component, and a third layer 53 provided on at least the first layer 51 and containing a third conductive polymer, and the second layer 52 is a solid electrolyte layer 50 , and the first layer 51 and the third layer 53 are arranged at least in a region in the plane of the solid electrolyte layer 50 where the second layer 52 is not arranged.
Thereby, leakage current can be suppressed while suppressing an increase in the equivalent series resistance of the electrolytic capacitor element 1 . The reason (action) that this effect is obtained is considered as follows. i.e.
(1) Since each layer contains a conductive polymer and the second layer 52 contains a binder component, the first layer 51 and the third layer 53 do not contain a binder component or have a high conductivity with a small amount of binder component. The second layer may be a dense and/or deformable membrane.
(2) Since the second layer 52 is partially arranged in the plane of the solid electrolyte layer 50, leakage current is likely to occur, for example, corners and tips of the anode 10 where stress is likely to concentrate. Since a dense and/or deformation-following conductive polymer film can be locally arranged, the corners and ridges of the tip surface 10a of the anode 10 (valve metal substrate) or along the mask layer 30 It is possible to suppress the formation of a thin film portion in a portion where the solid electrolyte layer 50 is difficult to adhere when the solid electrolyte layer 50 is formed, such as a portion where the solid electrolyte layer 50 is formed. As a result, leakage current can be reduced.
(3) The first layer 51 and the third layer 53, which are more highly conductive than the second layer 52, that is, can suppress an increase in equivalent series resistance, are arranged in the plane of the solid electrolyte layer 50. Since it is arranged at least in the region where the electrolytic capacitor element 1 is not formed, an increase in the equivalent series resistance of the entire electrolytic capacitor element 1 is prevented.
From the above, it is considered that leakage current can be reduced while suppressing an increase in the equivalent series resistance of the entire electrolytic capacitor element 1 .

The term "dense and/or deformable film" means that the film does not decompose when the anode is deformed due to heating during the sealing process, element lamination process, reflow process, etc. It shows a membrane that is strong and/or deformable so that it does not become thin. When heated, the second layer 52 expands differently from the first layer 51 and the third layer 53, and stress may occur. It is believed that the second layer 52 deforms to relieve the stress. In particular, if the film has deformation followability, the flexibility of the film is improved, and the characteristics of the electrolytic capacitor element 1 can be improved.

Only from the viewpoint of preventing leakage current, it is conceivable to dispose the second layer 52 over the entire plane of the solid electrolyte layer 50 . can lead to an increase in the equivalent series resistance of

In this specification, the term "conductive polymer" includes a main chain and a dopant.

Each of the first layer 51 and the third layer 53 preferably contains less binder components than the second layer 52, and more preferably contains no binder components. This makes it possible to more effectively suppress an increase in equivalent series resistance.

It should be noted that, here, "not containing a binder component" includes the case where the binder component is not substantially contained.

The second layer 52 is preferably a denser film than the first layer 51 and the third layer 53 . Thereby, leakage current can be suppressed more effectively.

Thus, in the electrolytic capacitor element 1 of the present embodiment, the second layer 52 contains the second conductive polymer (however, the presence or absence of a binder component does not matter), and the first layer 51 and the third layer It may be a denser film than the layer 53 .
This also makes it possible to suppress leakage current while suppressing an increase in the equivalent series resistance of the electrolytic capacitor element 1 . i.e.
(A) While each layer contains a conductive polymer, the second layer 52 is a denser film than the first layer 51 and the third layer 53, so the first layer 51 and the third layer 53 are It can be a highly conductive film and the second layer can be a dense film.
(B) Since the second layer 52 is partially arranged in the plane of the solid electrolyte layer 50, leakage current is likely to occur, for example, the corners and tip of the anode 10 where stress is likely to concentrate. Since the dense conductive polymer film can be locally arranged, the solid electrolyte layer 50 can be formed on the corners and ridges of the front end surface 10a of the anode 10 (valve metal substrate) or along the mask layer 30. It is possible to suppress the formation of a thin film portion at a location where the solid electrolyte layer 50 is difficult to adhere. As a result, leakage current can be reduced.
(C) The first layer 51 and the third layer 53, which are more highly conductive than the second layer 52, that is, can suppress an increase in equivalent series resistance, are arranged in the plane of the solid electrolyte layer 50. Since it is arranged at least in the region where the electrolytic capacitor element 1 is not formed, an increase in the equivalent series resistance of the entire electrolytic capacitor element 1 is prevented.
From the above, it is considered that leakage current can be reduced while suppressing an increase in the equivalent series resistance of the entire electrolytic capacitor element 1 .

Whether or not "the second layer is a denser film than the first and third layers" should be determined from cross-sectional photographs including the first, second and third layers. can be done. In the cross-sectional photograph, the second layer is observed to have a smooth (film-like) surface. On the other hand, the first and third layers are observed to have rougher surfaces than the second layer.

The method for making the second layer 52 more dense than the first layer 51 and the third layer 53 is not particularly limited to the above-described method of containing the binder component. may
(I) A polymerization reaction of the second conductive polymer is performed on the dielectric layer 20 at a low temperature.
(II) A slow polymerization reaction of the second conductive polymer is carried out on the dielectric layer 20 using a polymerization retardant (silane coupling agent or the like).
In either method, a fine polymer is likely to be generated, so that the second layer 52, which is a lump thereof, can be a dense layer.

As shown in FIGS. 3, 4 and 5, the anode 10 has six surfaces: a distal end surface 10a, a proximal end surface 10b, a pair of

main surfaces

10c and 10d, and a pair of

side surfaces

10e and 10f, It has corners where three of these six faces intersect and ridges where two of these six faces intersect, and the second layer 52 covers each corner 10g by the tip face 10a. ing. Since leakage current is generally likely to occur at the corners of the anode, this makes it possible to more effectively suppress the leakage current.

FIG. 6 is a perspective view schematically showing an example of an electrolytic capacitor element according to another embodiment of the invention. 7 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 6 along line CC. 8 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 6 taken along line DD. 6, 7 and 8 show the state before the conductive layer 60 of the cathode 40 is formed. In addition, FIG. 6 omits illustration of the dielectric layer 20 and shows a state in which the members inside the third layer 53 of the solid electrolyte layer 50 are seen through.

As shown in FIGS. 6, 7 and 8, the second layer 52 may further cover the tip surface 10a and each ridge line portion 10h formed by the tip surface 10a. Since leakage current is generally likely to occur even at the ridge of the anode, this can further effectively suppress the leakage current. Also, the second layer 52 is easier to form in the case shown in FIG. 6 than in the case shown in FIG.

In this specification, a corner portion is a portion where three surfaces intersect, and a ridge portion is a portion where two surfaces intersect. A corner portion formed by a certain surface means a corner portion where three surfaces including the surface intersect, and a ridge portion formed by a surface means a ridge portion where two surfaces including the surface intersect.

FIG. 9 is a perspective view schematically showing an example of an electrolytic capacitor element according to still another embodiment of the invention. 10 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 9 taken along line EE. 11 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 9 taken along line FF. 9, 10 and 11 show the state before the conductive layer 60 of the cathode 40 is formed. In addition, FIG. 9 omits illustration of the dielectric layer 20 and shows a state in which the members inside the third layer 53 of the solid electrolyte layer 50 are seen through.

As shown in FIGS. 9, 10 and 11, the second layer 52 may further cover the side surfaces 10e and 10f and the ridgeline portions 10j formed by the side surfaces 10e and 10f. Thereby, leakage current can be suppressed particularly effectively.

FIG. 12 is a perspective view schematically showing an example of an electrolytic capacitor element according to still another embodiment of the invention. 13 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 12 along line GG. 14 is a cross-sectional view of the electrolytic capacitor element shown in FIG. 12 taken along line HH. 12, 13 and 14 show the state before the conductive layer 60 of the cathode 40 is formed. In addition, FIG. 12 omits illustration of the dielectric layer 20 and shows a state in which the members inside the third layer 53 of the solid electrolyte layer 50 are seen through.

The second layer 52 may be arranged along the mask layer 30, as shown in FIGS. The thickness of the solid electrolyte layer becomes thin along the mask layer, and as a result, leakage current may occur. It is possible to effectively suppress the leakage current at the location.

Further, although illustration is omitted, a second layer having both the structure shown in FIG. 3, 6 or 9 and the structure shown in FIG. 12 may be formed. That is, for example, by combining the structures shown in FIGS. 6 and 12, the second layer 52 covers each corner 10g formed by the tip surface 10a, the tip surface 10a, and each ridgeline portion 10h formed by the tip surface 10a. , may be arranged along the mask layer 30 .

Each configuration in the electrolytic capacitor element 1 will be described in detail below.

The anode 10 is a square-shaped thin film (foil) formed from the valve action metal base 11, and preferably has a rectangular shape (strip shape) having a pair of long sides and a pair of short sides. The distal end surface 10a and the proximal end surface 10b are end surfaces located on a pair of sides (preferably a pair of short sides) of the anode 10, and the proximal end surface 10b is an exposed end surface not covered with the dielectric layer 20, It is exposed at one end face of the electrolytic capacitor and connected to an external electrode which will be described later. The anode 10 has a distal end surface 10a, a proximal end surface 10b,

main surfaces

10c and 10d, and

side surfaces

10e and 10f.

In this specification, "planar view" means viewing from the direction normal to the main surface of the anode (valve action metal substrate).

FIG. 15 is an enlarged cross-sectional view of the mask layer portion of the electrolytic capacitor element shown in FIG.

As shown in FIG. 15, each main surface of the valve action metal substrate 11 (anode 10) is provided with a plurality of recesses. Therefore, each main surface of the valve metal substrate 11 is porous. As a result, the surface area of the valve metal substrate 11 is increased. Both main surfaces of the valve action metal substrate 11 are not limited to being porous, and only one of the two main surfaces of the valve action metal substrate 11 may be porous.

The valve action metal substrate 11 is made of, for example, a single metal such as aluminum, tantalum, niobium, titanium, or zirconium, or a valve action metal such as an alloy containing these metals. An oxide film can be formed on the surface of the valve metal.

The valve action metal substrate 11 may be composed of a core portion and a porous portion provided on at least one main surface of the core portion. A porous fine powder sintered body or the like can be used as appropriate.

Dielectric layer 20 is provided here on the surface of anode 10 except for base end surface 10b. That is, the dielectric layer 20 is provided on the distal end surface 10a, the

main surfaces

10c and 10d, and the side surfaces 10e and 10f of the anode 10, while the dielectric layer 20 is provided on the proximal end surface 10b of the anode 10. not
However, dielectric layer 20 may be provided on at least one of

major surfaces

10c and 10d of anode 10 except for base end surface 10b.

The dielectric layer 20 is preferably composed of an oxide film provided on the surface of the valve action metal substrate 11 . For example, dielectric layer 20 is composed of an oxide of aluminum. The oxide of aluminum is formed by anodizing the surface of the valve action metal substrate 11, as will be described later.

The mask layer 30 is a linear (extending in a strip) insulating member provided on the dielectric layer 20 along the base end surface 10b of the anode 10, preferably along the short side of the anode 10, It separates the anode 10 and the cathode 40 to ensure insulation therebetween. The mask layer 30 divides the anode 10 into a region on the side of the proximal end surface 10b and a region on the side of the distal end surface 10a. Here, the mask layer 30 is arranged at a predetermined distance from the base end surface 10b, but may be arranged up to the base end surface 10b. The mask layer 30 is provided on the

main surfaces

10c and 10d and the side surfaces 10e and 10f of the anode 10 with the dielectric layer 20 interposed therebetween. It may be provided on at least one of 10c and 10d (however, the main surface on which dielectric layer 20 is provided).

As shown in FIG. 15, the mask layer 30 is preferably provided so as to fill a plurality of pores (concave portions) of the valve metal substrate 11 . However, the mask layer 30 only needs to partially cover the outer surface of the dielectric layer 20, and there may be pores (recesses) in the valve metal substrate 11 that are not filled with the mask layer 30. .

The mask layer 30 is made of an insulating material. The mask layer 30 is formed, for example, by applying a mask material such as a composition containing an insulating resin. Examples of insulating resins include polyphenylsulfone (PPS), polyethersulfone (PES), cyanate ester resin, fluorine resin (tetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, etc.), and soluble polyimide. Compositions comprising siloxane and epoxy resins, polyimide resins, polyamideimide resins, derivatives or precursors thereof, and the like are included.

The application of the mask material can be performed, for example, by screen printing, roller transfer, dispenser, inkjet printing, or the like.

The cathode 40 has a solid electrolyte layer 50 provided on the dielectric layer 20 and a conductive layer 60 provided on the solid electrolyte layer 50 . Also, the cathode 40 is provided on the dielectric layer 20 on the tip surface 10 a side of the mask layer 30 . That is, it is provided on the dielectric layer 20 in a region on the tip surface 10 a side of the anode 10 partitioned by the mask layer 30 .

The solid electrolyte layer 50 is provided on the dielectric layer 20 . As shown in FIG. 15 , the solid electrolyte layer 50 is preferably provided so as to fill a plurality of pores (recesses) of the valve metal substrate 11 . However, it is sufficient that a portion of the outer surface of the dielectric layer 20 is covered with the solid electrolyte layer 50, and there are pores (recesses) of the valve metal substrate 11 that are not filled with the solid electrolyte layer 50. good too.

The solid electrolyte layer 50 is provided on the dielectric layer 20 on the tip surface 10 a side of the mask layer 30 . That is, it is provided on the dielectric layer 20 in a region on the tip surface 10 a side of the anode 10 partitioned by the mask layer 30 .

As described above, the solid electrolyte layer 50 includes the first layer 51 containing the first conductive polymer, the second layer 52 containing the second conductive polymer, and the third conductive polymer. a third layer 53;
The second layer 52 is arranged only in a partial region of the plane of the solid electrolyte layer 50 instead of the entire region. That is, the second layer 52 is unevenly distributed not in the thickness direction of the solid electrolyte layer 50 but in the in-plane direction.
On the other hand, the first layer 51 and the third layer 53 are arranged at least in regions in the plane of the solid electrolyte layer 50 where the second layer 52 is not arranged. Therefore, the solid electrolyte layer 50 has at least one of the first layer 51, the third layer 53, and the second layer 52 arranged in its plane.

Here, as shown in FIG. The third layer 53 is provided on the first layer 51 and the second layer 52 . That is, the second layer 52 is arranged only in a part of the area on the first layer 51, and the third layer 53 is arranged on the second layer 52 and the first layer in the area where the second layer 52 is not arranged. layer 51 and .

In this way, by making the outermost surface of the solid electrolyte layer 50 the same material surface, here, all of them are the third layer 53, the formation variation in the subsequent processing (for example, the carbon layer formation step of graphite or the like) is reduced, Variations in the characteristics of the electrolytic capacitor element 1, particularly variations in ESR, can be reduced.

The thicknesses of the first layer 51 and the third layer 53 are not particularly limited, and may be, for example, approximately the same thicknesses as the inner and outer layers of a general solid electrolyte layer, respectively. Specifically, the maximum thickness of the first layer 51 is preferably 0.1 μm or more and 10 μm or less, more preferably 0.2 μm or more and 5 μm or less, and 0.3 μm or more and 3 μm or less. is more preferred. The maximum thickness of the third layer 53 is preferably 2 μm or more and 50 μm or less, more preferably 3 μm or more and 40 μm or less, and even more preferably 5 μm or more and 30 μm or less.

The thickness of the second layer 52 is also not particularly limited. More preferably, it is 3 μm or more and 30 μm or less.
The total thickness of the first layer 51, the second layer 52 and the third layer 53, that is, the thickness of the solid electrolyte layer 50 is preferably 100 μm or less, more preferably 50 μm or less, and 25 μm or less. is more preferred.

The location where the second layer 52 is arranged can be set as appropriate. A configuration in which the second layer 52 further covers the front end surface 10a of the anode 10 and each ridgeline portion 10h formed by the front end surface 10a (see FIG. 6, etc.); and each ridgeline portion 10j by each of the side surfaces 10e and 10f (see FIG. 9 etc.), and (4) a mode in which the second layer 52 is arranged along the mask layer 30 (see FIG. 12 etc.). preferable.

In the case of (1), the second layer 52 may cover at least one of the four corners 10g of the tip surface 10a, but preferably covers the four corners 10g.
Also, FIG. 3 shows a case where two corners 10g (vertical corners 10g in FIG. 3) formed by the

same side surface

10e or 10f are independently covered with the second layer 52. The corner 10 g may be integrally covered with the second layer 52 . That is, the four ridgeline portions 10h formed by the tip surface 10a include two ridgeline portions 10ha formed by the

side surface

10e or 10f and the tip surface 10a, but the second layer 52 may further cover the ridgeline portions 10ha.

In the case of (2), the second layer 52 may cover at least one of the four ridgeline portions 10h formed by the tip surface 10a, but preferably covers each of the four ridgeline portions 10h. In this way, the second layer 52 preferably covers the tip of the anode 10 (the part including the tip face 10a as a part). is preferably provided over each of the

In case (3), the second layer 52 may cover at least one of the two

sides

10e and 10f, but preferably covers the two

sides

10e and 10f respectively. The second layer 52 may cover at least one of the four ridgeline portions 10j formed by the side surfaces 10e and 10f, but preferably covers the four ridgeline portions 10j.
In this case, the second layer 52 does not have to cover the tip end face 10a and the ridge line portions 10h formed by the tip end face 10a.

In case (4), the second layer 52 may be arranged along the mask layer 30 on at least one of the

main surfaces

10c and 10d and the side surfaces 10e and 10f of the anode 10, although these are preferably arranged along the mask layer 30 on each side of the .
In this case, it is preferable that no gap is provided between the second layer 52 and the mask layer 30 , and the second layer 52 is arranged side by side with the mask layer 30 while being in contact with the mask layer 30 . preferably.
Furthermore, while the first layer 51 alone may create a gap with the mask layer 30 , the second layer 52 preferably fills the gap between the first layer 51 and the mask layer 30 .

In any case, the shape of the second layer 52 is not particularly limited. For example, as shown in FIG. A shape in which at least two straight lines out of the contour lines of the shape obliquely intersect, and a shape in which at least one straight line out of the contour lines of the peripheral edge is curved.

A conductive polymer having a main chain such as polypyrrole, polythiophene, polyaniline, or the like is used as the material forming the solid electrolyte layer 50 . Among these, polythiophene is preferred, and poly(3,4-ethylenedioxythiophene) called PEDOT is particularly preferred. Moreover, the conductive polymer contains a dopant such as polystyrene sulfonic acid (PSS).

At least part of the solid electrolyte layer 50, specifically the second layer 52, contains a binder component. On the other hand, the first layer 51 and the third layer 53 may each contain a binder component. In that case, the content of the binder component contained in each of the first layer 51 and the third layer 53 is It is preferably less than the content of the binder component contained in the second layer 52 . More preferably, each of the first layer 51 and the third layer 53 does not contain a binder component. On the other hand, since the second layer 52 is partially arranged in the plane of the solid electrolyte layer 50, the content of the binder component can be increased compared to the conventional case.

More specifically, the content of the binder component contained in the first layer 51 or the third layer 53 is preferably 0.1% by weight or less, more preferably 0.05% by weight or less, It is more preferably 0.01% by weight or less. The content of the binder component contained in the second layer 52 is preferably 0.1% by weight or more and 20% by weight or less, more preferably 0.3% by weight or more and 10% by weight or less. More preferably, it is 5% by weight or more and 5% by weight or less.

Suitable specific examples of the binder component contained in the second layer 52 include, for example, polyisoprene, polystyrene, polyethylene, polyvinylpyrrolidone, polyvinyl alcohol, polymethyl methacrylate, polyacrylonitrile, polyester (preferably polyethylene terephthalate), polyamide, Polyurethane, polycarbonate, cellulose, cellulose nanofibers, polyphthalates, and the like. These may be used alone or in combination of two or more.

Suitable specific examples of the binder component that can be included in the first layer 51 and the third layer 53 are the same as the binder component included in the second layer 52 . These may be used alone or in combination of two or more.

The content of the binder component and the conductivity of the solid electrolyte layer 50 are in a trade-off relationship. For example, the more the binder component, the lower the conductivity of the second layer 52 . However, the first layer 51, the second layer 52 and the third layer 53 all function as conductive layers.

The solid electrolyte layer 50 is formed by depositing a conductive material such as poly(3,4-ethylenedioxythiophene) on the surface of the dielectric layer 20 using a liquid containing a polymerizable monomer such as 3,4-ethylenedioxythiophene. It is formed by a method of forming a polymeric film, a method of applying a dispersion of a conductive polymer such as poly(3,4-ethylenedioxythiophene) to the surface of the dielectric layer 20 and drying it, or the like. . In particular, in the method of forming a polymer film of a conductive polymer using a liquid containing a polymerizable monomer, each corner portion 10g and each ridge portion 10h of the anode 10, Since the thickness of the solid electrolyte layer 50 tends to be thin above 10j and above the mask layer 30, leakage current can be suppressed more effectively.

More specifically, the first layer 51 and the third layer 53 are formed by forming poly(3,4 It is preferably formed by a method of forming a polymer film of a conductive polymer such as (ethylenedioxythiophene).

On the other hand, the second layer 52 is preferably formed by, for example, a method of applying a conductive polymer dispersion containing a binder component onto the dielectric layer 20 and drying it. Here, since the second layer 52 contains a binder component and its conductivity decreases, the conductive polymer for the second layer 52 is poly(3,4-ethylenedioxythiophene, which has excellent conductivity. ) are particularly preferred.
Thus, the first conductive polymer contained in the first layer 51, the second conductive polymer contained in the second layer 52, and the third conductive polymer contained in the third layer 53 may be the same conductive polymer (having the same main chain and dopant), or at least two of them may be different conductive polymers (at least the main chain and dopant one side may be different).

The first layer 51 is preferably formed as an inner layer that fills the pores (recesses) of the valve action metal substrate 11 . The inner layer can be formed by, for example, a dipping method, sponge transfer, screen printing, dispenser, inkjet printing, or the like.

Similarly, the formation of the second layer 52 can be performed by, for example, an immersion method, sponge transfer, screen printing, dispenser, inkjet printing, etc. In the above cases (1), (3) and (4), Inkjet printing is preferred, and in the case of (2) above, immersion is preferred.

The third layer 53 is preferably formed as an outer layer covering the entire dielectric layer 20 . The outer layer can be formed by, for example, an immersion method, sponge transfer, screen printing, dispenser, inkjet printing, or the like.

The conductive layer 60 is provided on the solid electrolyte layer 50 . The conductive layer 60 covers substantially the entire solid electrolyte layer 50 and is in contact with the mask layer 30 . Note that the conductive layer 60 may be arranged up to the front of the mask layer 30 . The conductive layer 60 has a substantially constant thickness.

The conductive layer 60 includes, for example, a carbon layer or a cathode conductor layer. Also, the conductive layer 60 may be a composite layer in which a cathode conductor layer is provided on the outer surface of a carbon layer, or a mixed layer containing carbon and a cathode conductor layer material.

The carbon layer is formed, for example, by applying a carbon paste containing carbon particles and resin to the surface of the solid electrolyte layer 50 and drying it.

The carbon paste can be applied by, for example, an immersion method, sponge transfer, screen printing, spray coating, dispenser, inkjet printing, or the like.

The cathode conductor layer is formed, for example, by a method of applying a conductive paste containing metal particles such as gold, silver, copper, platinum, and a resin to the surface of the solid electrolyte layer or carbon layer and drying the paste. The cathode conductor layer is preferably a silver layer.

The conductive paste can be applied by, for example, dipping, sponge transfer, screen printing, spray coating, dispenser, inkjet printing, or the like.

[Manufacturing method of electrolytic capacitor element]
A method for manufacturing the electrolytic capacitor element 1 will be described below. In the following example, a method for simultaneously manufacturing a plurality of electrolytic capacitor elements using a large-sized valve action metal substrate will be described.

FIG. 16 is a schematic diagram showing an example of a process of preparing a valve metal substrate on which a mask layer is formed.

As shown in FIG. 16, a valve action metal substrate 11A having a dielectric layer 20 on its surface is prepared. Valve action metal substrate 11A includes a plurality of element portions 12 and support portions 13 . Each element portion 12 is strip-shaped and protrudes from the support portion 13 . A mask layer 30 is formed on the dielectric layer 20 of each element portion 12 .

First, the valve action metal substrate 11A having a porous portion on its surface is cut by laser processing, punching, or the like to be processed into a shape including a plurality of element portions 12 and support portions 13 .

Next, mask layers 30 are formed on both main surfaces and both side surfaces of the element portions 12 along the short sides of each element portion 12 .

After that, the valve action metal substrate 11A is anodized to form an oxide film that will become the dielectric layer 20 on the surface of the valve action metal substrate 11A. At this time, an oxide film is also formed on the side surfaces of the element portion 12 cut by laser processing, punching, or the like. A chemically processed foil on which an oxide of a valve action metal has already been formed may be used as the valve action metal substrate 11A. In this case also, an oxide film is formed on the side surface of the cut element portion 12 by anodizing the cut valve metal substrate 11A.

FIG. 17 is a schematic diagram showing an example of the process of forming the first layer and the third layer of the solid electrolyte layer.

A first layer 51 (see FIG. 3, etc.) of the solid electrolyte layer 50 is formed on the dielectric layer 20 of the element section 12 . As shown in FIG. 17, it is preferable to apply the treatment liquid for forming the first layer 51 to the valve metal substrate 11A by an immersion method. FIG. 17 shows a state in which the processing liquid 70 for forming the first layer 51 or the processing liquid 72 for forming the third layer 53 is supplied to the processing bath 75 .

As the treatment liquid 70 for forming the first layer 51, for example, a liquid containing a polymerizable monomer such as 3,4-ethylenedioxythiophene and an oxidizing agent such as iron (III) p-toluenesulfonate is used. . A liquid containing a polymerizable monomer can be adhered to the outer surface of the dielectric layer 20 and chemically polymerized to form a film containing the first conductive polymer. Alternatively, as the treatment liquid 70 for forming the first layer 51, a dispersion liquid of the first conductive polymer is used. A conductive polymer film can be formed by attaching the dispersion liquid of the first conductive polymer to the outer surface of the dielectric layer 20 and drying it. This conductive polymer film becomes the first layer 51 of the solid electrolyte layer 50 .

The treatment liquid 70 for forming the first layer 51 may contain the binder component described above, but preferably does not contain the binder component. When the treatment liquid 70 contains a binder component, its concentration in the treatment liquid 70 is preferably 0.1% by weight or less, more preferably 0.05% by weight or less, and more preferably 0.01% by weight. It is more preferable to:

As shown in FIG. 17, by immersing the valve action metal substrate 11A in the treatment liquid 70, the treatment liquid 70 is impregnated into the porous portion of the valve action metal substrate 11A. After being immersed for a predetermined time, the valve metal substrate 11A is pulled out of the treatment liquid 70 and dried at a predetermined temperature for a predetermined time. The immersion in the treatment liquid 70, the withdrawal, and the drying may be repeated a predetermined number of times. As a result, the first layer 51 of the solid electrolyte layer 50 is formed.

For example, the valve action metal substrate 11A is immersed in a liquid containing a polymerizable monomer (a dispersion liquid containing a first conductive polymer may be used), taken out, and then dried to form the first layer 51 as a solid electrolyte. It is formed as an inner layer of the layer 50 (a portion provided on the dielectric layer 20 and filling the pores of the valve action metal substrate 11). The immersion in the liquid containing the polymerizable monomer, pulling out and drying may be performed multiple times.

After forming the first layer 51, the primer layer may be formed by immersing the valve metal substrate 11A in a solution containing a primer compound, pulling it out, and drying it. When the primer layer is formed, the valve metal substrate 11A is washed with pure water to remove excess primer compound. After washing, a drying process is performed.

FIG. 18 is a schematic diagram showing an example of the process of forming the second layer of the solid electrolyte layer.

After forming the first layer 51 of the solid electrolyte layer 50 , the second layer 52 (see FIG. 6 etc.) of the solid electrolyte layer 50 is formed on the first layer 51 . For example, as shown in FIG. 18, a treatment liquid for forming the second layer 52 is applied to the first layer 51 by an immersion method. FIG. 18 shows a state in which the processing liquid 71 for forming the second layer 52 is supplied to the processing bath 76 .

As the treatment liquid 71 for forming the second layer 52, for example, a second conductive polymer dispersion containing a binder component is used. By applying this dispersion to the outer surface of the first layer 51 and drying it, a conductive polymer film containing a binder component can be formed. Alternatively, the treatment liquid 71 for forming the second layer 52 contains a polymerizable monomer such as 3,4-ethylenedioxythiophene, an oxidizing agent such as iron (III) p-toluenesulfonate, and a binder component. A liquid may be used. A liquid containing a polymerizable monomer containing a binder component can be adhered to the outer surface of the first layer 51 and chemically polymerized to form a conductive polymer film containing the binder component. The conductive polymer film containing this binder component becomes the second layer 52 of the solid electrolyte layer 50 .

The concentration of the binder component in the treatment liquid 71 is preferably 0.1% by weight or more and 20% by weight or less, more preferably 0.3% by weight or more and 10% by weight or less, and 0.5% by weight. % or more and 5% by weight or less is more preferable.

As shown in FIG. 18, the treatment liquid 71 adheres to the outer surface of the first layer 51 by immersing the tip of the valve action metal substrate 11A in the treatment liquid 71 . After being immersed for a predetermined time, the valve metal substrate 11A is pulled out of the treatment liquid 71 and dried at a predetermined temperature for a predetermined time. The immersion in the treatment liquid 71, the withdrawal, and the drying may be repeated a predetermined number of times. As a result, the second layer 52 of the solid electrolyte layer 50 as shown in FIG. 6 is formed.

Separately from this method, a treatment liquid for forming the second layer 52 (for example, the dispersion liquid of the second conductive polymer or the liquid containing the polymerizable monomer) is applied to the outside of the first layer 51 by inkjet printing. The second layer 52 of the solid electrolyte layer 50 may be formed in a predetermined region by discharging onto the surface. Thereby, the second layer 52 of the solid electrolyte layer 50 as shown in FIGS. 3, 9 and 12 can be formed.

After forming the second layer 52 of the solid electrolyte layer 50 , the third layer 53 (see FIG. 3 etc.) of the solid electrolyte layer 50 is formed on the first layer 51 and the second layer 52 . For example, as shown in FIG. 17, it is preferable to apply a treatment liquid 72 for forming the third layer 53 to the first layer 51 and the second layer 52 by an immersion method.

As the treatment liquid 72 for forming the third layer 53, for example, a liquid containing a polymerizable monomer such as 3,4-ethylenedioxythiophene and an oxidizing agent such as iron (III) p-toluenesulfonate is used. . A liquid containing a polymerizable monomer can be adhered to the outer surfaces of the first layer 51 and the second layer 52 and chemically polymerized to form a film containing the third conductive polymer. Alternatively, as the treatment liquid 72 for forming the third layer 53, a dispersion liquid of a third conductive polymer is used. A conductive polymer film can be formed by attaching a dispersion liquid of the third conductive polymer to the outer surfaces of the first layer 51 and the second layer 52 and drying it. This conductive polymer film becomes the third layer 53 of the solid electrolyte layer 50 .

The treatment liquid 72 for forming the third layer 53 may contain the binder component described above, but preferably does not contain the binder component. When the treatment liquid 72 contains a binder component, its concentration in the treatment liquid 72 is preferably 0.1% by weight or less, more preferably 0.05% by weight or less, and more preferably 0.01% by weight. It is more preferable to:

As shown in FIG. 17, the treatment liquid 72 adheres to the outer surfaces of the first layer 51 and the second layer 52 by immersing the valve metal substrate 11A in the treatment liquid 72 . After being immersed for a predetermined time, the valve metal substrate 11A is pulled out of the treatment liquid 72 and dried at a predetermined temperature for a predetermined time. The immersion in the treatment liquid 72, the withdrawal, and the drying may be repeated a predetermined number of times. As a result, the third layer 53 of the solid electrolyte layer 50 is formed.

For example, the valve metal substrate 11A is immersed in a liquid containing a polymerizable monomer (a dispersion liquid containing a third conductive polymer may be used), taken out, and then dried to form the third layer 53 as a solid electrolyte. It is formed as the outer layer of layer 50 (the portion that is connected to the inner layer and covers the entire dielectric layer 20). The immersion in the liquid containing the polymerizable monomer, pulling out and drying may be performed multiple times.

As described above, the first layer 51, the second layer 52 and the third layer 53 of the solid electrolyte layer 50 are formed in predetermined regions.

After the solid electrolyte layer 50 is formed, the valve metal substrate 11A is immersed in the carbon paste, pulled out, and dried to form a carbon layer in a predetermined region.

After forming the carbon layer, the valve action metal substrate 11A is immersed in a conductive paste containing metal particles such as silver paste, pulled out, and dried to form a cathode conductor layer in a predetermined region.

Then, the valve action metal substrate 11A is cut to separate the element portion 12, thereby forming the strip-shaped anode 10 whose cut surface serves as the base end surface 10b.

The electrolytic capacitor element 1 is obtained through the above steps.

[Electrolytic capacitor]
An example of an electrolytic capacitor including the electrolytic capacitor element of the present invention will be described below. Note that the electrolytic capacitor element of the present invention may be included in electrolytic capacitors having other configurations. For example, lead frames may be used as external electrodes. The electrolytic capacitor may also include electrolytic capacitor elements other than the electrolytic capacitor element of the present invention (that is, electrolytic capacitor elements having a structure different from that of the electrolytic capacitor element of the present invention).

FIG. 19 is a perspective view schematically showing an example of an electrolytic capacitor including an electrolytic capacitor element according to an embodiment of the invention. 20 is a cross-sectional view of the electrolytic capacitor shown in FIG. 19 taken along line ZZ.

19 and 20, L indicates the length direction of the electrolytic capacitor 100 and the exterior body 110, W indicates the width direction, and T indicates the height direction. Here, the length direction L, the width direction W, and the height direction T are orthogonal to each other.

As shown in FIGS. 19 and 20, the electrolytic capacitor 100 has a substantially rectangular parallelepiped outer shape. The electrolytic capacitor 100 is a solid electrolytic capacitor, and includes an exterior body 110 , a first external electrode 120 , a second external electrode 130 , and a plurality of electrolytic capacitor elements 1 .

The exterior body 110 seals a plurality of electrolytic capacitor elements 1 . That is, a plurality of electrolytic capacitor elements 1 are embedded in the exterior body 110 . Note that the exterior body 110 may seal one electrolytic capacitor element 1 . That is, one electrolytic capacitor element 1 may be embedded inside the exterior body 110 .

The exterior body 110 has a substantially rectangular parallelepiped outer shape. The exterior body 110 has a first major surface 110a and a second major surface 110b that face each other in the height direction T, a first side face 110c and a second side face 110d that face each other in the width direction W, and a first side face 110c and a second side face 110d that face each other in the length direction L. It has one end face 110e and a second end face 110f.

As described above, the exterior body 110 has a substantially rectangular parallelepiped outer shape, and it is preferable that the corners and ridges are rounded.

The exterior body 110 is made of sealing resin, for example.

The sealing resin contains at least resin, and preferably contains resin and filler.

As the resin, epoxy resin, phenol resin, polyimide resin, silicone resin, polyamide resin, liquid crystal polymer, etc. are preferably used.

Silica particles, alumina particles, etc. are preferably used as the filler.

A material containing solid epoxy resin, phenol resin, and silica particles is preferably used as the sealing resin.

When a solid sealing resin is used, resin molds such as compression molds and transfer molds are preferably used, and compression molds are more preferably used. Moreover, when using a liquid sealing resin, molding methods such as a dispensing method and a printing method are preferably used. Among them, it is preferable to seal the periphery of the electrolytic capacitor element 1 with a sealing resin by compression molding to form the exterior body 110 .

The exterior body 110 may be composed of a substrate and a sealing resin provided on the substrate. The substrate is, for example, an insulating resin substrate such as a glass epoxy substrate. In this case, the bottom surface of the substrate constitutes the second main surface 110b of the exterior body 110. As shown in FIG. The thickness of the substrate is, for example, 100 μm.

A plurality of electrolytic capacitor elements 1 are stacked in the height direction T with conductive adhesive 140 interposed therebetween. The extension direction of each of the plurality of electrolytic capacitor elements 1 is substantially parallel to the first main surface 110 a and the second main surface 110 b of the outer package 110 . Electrolytic capacitor elements 1 are bonded to each other via conductive adhesive 140 .

The conductive adhesive 140 contains, for example, metal particles such as gold, silver, copper, platinum, etc., and resin. Here, silver is used as the metal particles and acrylic resin is used as the resin.
Other examples of the resin contained in the conductive adhesive 140 include urethane resin, epoxy resin, polyimide resin, phenol resin, and the like.

The first external electrode 120 is provided on the first end face 110e of the exterior body 110. In FIG. 19, the first external electrode 120 is provided from the first end surface 110e of the exterior body 110 over each of the first main surface 110a, the second main surface 110b, the first side surface 110c, and the second side surface 110d. there is First external electrode 120 is electrically connected to conductive layer 60 of cathode 40 of electrolytic capacitor element 1 exposed from exterior body 110 at first end face 110e. The first external electrode 120 may be directly or indirectly connected to the conductive layer 60 on the first end face 110 e of the outer casing 110 .

The second external electrode 130 is provided on the second end face 110f of the exterior body 110. In FIG. 19, the second external electrode 130 is provided from the second end surface 110f of the exterior body 110 over each of the first main surface 110a, the second main surface 110b, the first side surface 110c, and the second side surface 110d. there is Second external electrode 130 is electrically connected to anode 10 (valve metal substrate 11) of electrolytic capacitor element 1 exposed from exterior body 110 at second end surface 110f. The second external electrode 130 may be directly or indirectly connected to the anode 10 (valve metal substrate 11 ) at the second end surface 110 f of the exterior body 110 .

The first external electrode 120 and the second external electrode 130 are each formed by a dip coating method, a screen printing method, a transfer method, an inkjet printing method, a dispensing method, a spray coating method, a brush coating method, a drop casting method, an electrostatic coating method, It is preferably formed by at least one method selected from the group consisting of plating and sputtering.

The first external electrode 120 preferably has a resin electrode layer containing a conductive component and a resin component. Since the first external electrode 120 contains a resin component, the adhesion between the first external electrode 120 and the sealing resin of the exterior body 110 is enhanced, thereby improving the reliability.

The second external electrode 130 preferably has a resin electrode layer containing a conductive component and a resin component. Since the second external electrode 130 contains a resin component, the adhesion between the second external electrode 130 and the sealing resin of the exterior body 110 is enhanced, thereby improving the reliability.

The conductive component preferably contains, as a main component, an elemental metal such as silver, copper, nickel, or tin, or an alloy containing at least one of these metals.

The resin component preferably contains epoxy resin, phenol resin, etc. as the main component.

The resin electrode layer is formed by methods such as dip coating, screen printing, transfer, inkjet printing, dispensing, spray coating, brush coating, drop casting, and electrostatic coating. Among them, the resin electrode layer is preferably a printed resin electrode layer formed by applying a conductive paste by a screen printing method. When the resin electrode layer is formed by applying a conductive paste by a screen printing method, compared with the case where the resin electrode layer is formed by applying a conductive paste by a dip coating method, the first external electrode 120 And the second external electrode 130 tends to be flat. That is, the thicknesses of the first external electrode 120 and the second external electrode 130 tend to be uniform.

When the first external electrode 120 has a resin electrode layer, since both the first external electrode 120 and the cathode conductor layer contain a resin component, the adhesiveness between the first external electrode 120 and the cathode conductor layer is increased, so reliability is improved. improves.

At least one of the first external electrode 120 and the second external electrode 130 may have a so-called plated layer formed by a plating method. Examples of plating layers include zinc/silver/nickel layers, silver/nickel layers, nickel layers, zinc/nickel/gold layers, nickel/gold layers, zinc/nickel/copper layers, and nickel/copper layers. On these plated layers, for example, a copper plated layer, a nickel plated layer, and a tin plated layer are preferably provided in this order (or with the exception of some plated layers).

At least one of the first external electrode 120 and the second external electrode 130 may have both a resin electrode layer and a plating layer. For example, the second external electrode 130 may have a resin electrode layer connected to the anode 10 (valve metal substrate 11) and an outer plated layer provided on the surface of the resin electrode layer. The second external electrode 130 includes an inner plated layer connected to the anode 10 (valve metal substrate 11), a resin electrode layer provided to cover the inner plated layer, and a resin electrode layer provided on the surface of the resin electrode layer. and an outer plated layer.

In the above embodiment, the case where the first layer 51 and the third layer 53 are arranged over the entire surface of the solid electrolyte layer 50 has been described, but at least one of the first layer 51 and the third layer 53 is , may be partially arranged in the plane of the solid electrolyte layer 50 . That is, at least one of the first layer 51 and the third layer 53 may be selectively arranged only in a region in the plane of the solid electrolyte layer 50 where the second layer 52 is not arranged. In this case, inkjet printing is suitable as a method for forming the first layer 51 and/or the third layer 53 .

Further, in the above embodiment, the case where the electrolytic capacitor element 1 is a solid electrolytic capacitor using a conductive polymer as an electrolyte material has been described. A so-called hybrid type electrolytic capacitor element may be used in which an electrolytic solution is used together with the solid electrolyte.

Further, in the above-described embodiment, the case where the electrolytic capacitor element 1 is used in the chip-type electrolytic capacitor 100 has been described, but the electrolytic capacitor element of the present invention can be used by being embedded in a package substrate included in a semiconductor device, for example. may be Here, examples of semiconductor devices include semiconductor composite devices in which a voltage regulator (voltage control device) and a load are mounted on a package substrate.

Examples that more specifically disclose the electrolytic capacitor element of the present invention are shown below. It should be noted that the present invention is not limited only to these examples.

(Example 1)
An aluminum foil having an etching layer on its surface was prepared as an anode (valve metal substrate), and immersed in an ammonium adipate aqueous solution for anodization to form a dielectric layer on the surface of the aluminum foil.

Next, a mask layer is formed on both main surfaces and both side surfaces of the foil through the dielectric layer by roller-transferring a composition comprising a soluble polyimidesiloxane and an epoxy resin onto the aluminum foil having the dielectric layer formed on the surface. formed.

Next, an aluminum foil was immersed in a mixed solution of iron (III) paratoluenesulfonate, 3,4-ethylenedioxythiophene, and 1-butanol to just below the mask layer, pulled out, and then dried. As a result, 3,4-ethylenedioxythiophene was chemically polymerized on the dielectric layer to form a first solid electrolyte layer on the dielectric layer.

Next, a PEDOT-PSS dispersion containing 5% by weight of polyester as a binder component is applied only to each corner of the aluminum foil by inkjet printing, and dried to form a second solid electrolyte layer on the first layer. partially formed (see FIG. 3).
The PEDOT-PSS dispersion is an aqueous dispersion of poly(3,4-ethylenedioxythiophene) and polystyrenesulfonic acid.

Next, an aluminum foil was immersed in a mixed solution of iron (III) paratoluenesulfonate, 3,4-ethylenedioxythiophene, and 1-butanol to just below the mask layer, pulled out, and then dried. As a result, 3,4-ethylenedioxythiophene was chemically polymerized on the first and second layers to form a third solid electrolyte layer on the first and second layers.

Next, an electrolytic capacitor element was obtained by sequentially forming a carbon layer and a silver layer.

The resulting four electrolytic capacitor elements were laminated using a conductive adhesive to obtain a laminate. After that, the laminate was sealed with an epoxy resin and separated into pieces using a dicer. Next, a silver paste containing a resin component was screen-printed on the cathode-side and anode-side end surfaces of the solidified sealing body to form external electrodes on the cathode and anode, thereby obtaining a finished electrolytic capacitor.

(Example 2)
A finished electrolytic capacitor was obtained in the same manner as in Example 1, except that the solid electrolyte layer was formed as follows.

Specifically, an aluminum foil having a dielectric layer formed on its surface was immersed in a mixed solution of iron (III) p-toluenesulfonate, 3,4-ethylenedioxythiophene, and 1-butanol to just below the mask layer, and pulled up. and then dried. As a result, 3,4-ethylenedioxythiophene was chemically polymerized on the dielectric layer to form a first solid electrolyte layer on the dielectric layer.

Next, only the tip (lower end) of the aluminum foil is immersed in a PEDOT-PSS dispersion containing 5% by weight of polyester as a binder component, pulled out, and dried to form a solid electrolyte layer on the first layer. A second layer was partially formed (see FIG. 6).

(Example 3)
A finished electrolytic capacitor was obtained in the same manner as in Example 1, except that the solid electrolyte layer was formed as follows.

Next, a PEDOT-PSS dispersion containing 5% by weight of polyester as a binder component is applied by inkjet printing to the tip surface (bottom surface), each side surface, each corner portion, and each ridge portion of the aluminum foil. and dried to partially form the second layer of the solid electrolyte layer on the first layer (see FIG. 9).

(Comparative example 1)
A finished electrolytic capacitor was obtained in the same manner as in Example 1, except that the solid electrolyte layer was formed as follows.

That is, an aluminum foil having a dielectric layer formed on its surface was immersed in a mixed solution of iron (III) p-toluenesulfonate, 3,4-ethylenedioxythiophene and 1-butanol up to just below the mask layer, and then pulled out. By drying, a first layer of a solid electrolyte layer was formed on the dielectric layer.

Next, without forming the second layer of the solid electrolyte layer, the aluminum foil was immersed in a mixed solution of iron (III) p-toluenesulfonate, 3,4-ethylenedioxythiophene, and 1-butanol to just below the mask layer. , pulled up, and dried to form a third layer of the solid electrolyte layer on the first layer.

(Comparative example 2)
A finished electrolytic capacitor was obtained in the same manner as in Example 1, except that the solid electrolyte layer was formed as follows.

Next, the solid electrolyte layer is immersed in a PEDOT-PSS dispersion containing 5% by weight of polyester as a binder component so as to cover the entire first layer, pulled out, and dried to cover the entire area of the first layer. to form a second layer of

Next, an aluminum foil is immersed in a mixed solution of iron (III) p-toluenesulfonate, 3,4-ethylenedioxythiophene, and 1-butanol to just below the mask layer, pulled out, and dried to form a second layer. A third layer of a solid electrolyte layer was formed thereon.

(Comparative Example 3)
A finished electrolytic capacitor was obtained in the same manner as in Example 1, except that the solid electrolyte layer was formed as follows.

Next, only the front end (lower end) of the aluminum foil was immersed in a polyimide resin solution, pulled out, and then dried to partially form an insulating layer on the first layer.

Next, an aluminum foil is immersed in a mixed solution of iron (III) p-toluenesulfonate, 3,4-ethylenedioxythiophene, and 1-butanol to just below the mask layer, pulled out, and dried to form the first layer. And a third layer of a solid electrolyte layer was formed on the insulating layer.

(Comparative Example 4)
A finished electrolytic capacitor was obtained in the same manner as in Example 1, except that the solid electrolyte layer was formed as follows.

Next, only the tip (lower end) of the aluminum foil is immersed in a PEDOT-PSS dispersion containing no binder component, pulled out, and then dried to partially form the second layer of the solid electrolyte layer on the first layer. was formed.

Next, an aluminum foil is immersed in a mixed solution of iron (III) p-toluenesulfonate, 3,4-ethylenedioxythiophene, and 1-butanol to just below the mask layer, pulled out, and dried to form the first layer. and a third layer of a solid electrolyte layer was formed on the second layer.

Regarding the electrolytic capacitors obtained in Examples 1-3 and Comparative Examples 1-4, the equivalent series resistance (ESR) and leakage current (LC) of finished products were evaluated. The results are shown in Table 1 below.
ESR indicates a relative value to the ESR of the electrolytic capacitor obtained in Comparative Example 1.

In Examples 1, 2, and 3, the dense second layer containing the binder component is formed only at locations where leakage current is likely to occur, such as the corners of the tip of the aluminum foil. The LC non-defective product rate was improved, and the ESR was lower than in Comparative Example 2. Example 2 had a lower ESR than Comparative Example 3. Compared with Example 2, Comparative Example 4 had a lower LC non-defective rate because the second layer did not contain a binder component.

FIG. 21 shows a SEM photograph of the cross section of the electrolytic capacitor of Example 1.

As shown in FIG. 21, it was confirmed that the inclusion of the binder component made the second layer a denser film than the first and third layers. That is, in cross-sectional photographs, the second layer was observed to have a smooth (film-like) surface. On the other hand, the first and third layers were observed to have rougher surfaces than the second layer.

Reference Signs List 1 electrolytic capacitor element 10 anode 10a tip surface 10b

base end surface

10c, 10d

main surface

10e, 10f side surface 10g corner portions 10h, 10ha, 10j edge portion 11, 11A valve action metal substrate 12 element portion 13 support portion 20 dielectric layer 30 mask Layer 40 Cathode 50 Solid electrolyte layer 51 First layer 52 Second layer 53 Third layer 60 Conductive layer 70, 71, 72

Treatment liquid

75, 76 Treatment bath 100 Electrolytic capacitor 110 Exterior body 110a First main surface 110b Second main surface 110c first side face 110d second side face 110e first end face 110f second end face 120 first external electrode 130 second external electrode 140 conductive adhesive

Claims

an anode composed of a valve metal substrate and having a distal end surface and a proximal end surface;
a dielectric layer provided on at least one main surface of the anode except at least the base end surface;
a mask layer made of an insulating material and provided on the dielectric layer along the proximal surface;
a cathode provided on the dielectric layer on the tip surface side of the mask layer,
The cathode has a solid electrolyte layer provided on the dielectric layer and a conductive layer provided on the solid electrolyte layer,
The solid electrolyte layer is provided on the dielectric layer and comprises a first layer containing a first conductive polymer, a second layer containing a second conductive polymer and a binder component, and at least the first a third layer provided on the layer and comprising a third conductive polymer;
The second layer is partially arranged in the plane of the solid electrolyte layer,
The electrolytic capacitor element, wherein the first layer and the third layer are arranged at least in a region in which the second layer is not arranged in the plane of the solid electrolyte layer.
2. The electrolytic capacitor element according to claim 1, wherein each of said first layer and said third layer contains less binder component than said second layer.
3. The electrolytic capacitor element according to claim 2, wherein each of said first layer and said third layer does not contain a binder component.
The binder component contained in the second layer is selected from polyisoprene, polystyrene, polyethylene, polyvinylpyrrolidone, polyvinyl alcohol, polymethylmethacrylate, polyacrylonitrile, polyester, polyamide, polyurethane, polycarbonate, cellulose, cellulose nanofibers and polyphthalates. 4. The electrolytic capacitor element according to claim 1, comprising at least one component selected from the group consisting of:
The electrolytic capacitor element according to any one of claims 1 to 4, wherein said second layer is a denser film than said first and third layers.
an anode composed of a valve metal substrate and having a distal end surface and a proximal end surface;
a dielectric layer provided on at least one main surface of the anode except at least the base end surface;
a mask layer made of an insulating material and provided on the dielectric layer along the proximal surface;
a cathode provided on the dielectric layer on the tip surface side of the mask layer,
The cathode has a solid electrolyte layer provided on the dielectric layer and a conductive layer provided on the solid electrolyte layer,
The solid electrolyte layer is provided on the dielectric layer and includes a first layer containing a first conductive polymer, a second layer containing a second conductive polymer, and at least on the first layer a third layer provided and comprising a third conductive polymer;
The second layer is partially arranged in the plane of the solid electrolyte layer,
The first layer and the third layer are arranged at least in a region where the second layer is not arranged in the plane of the solid electrolyte layer,
The electrolytic capacitor element, wherein the second layer is a denser film than the first and third layers.
The anode has six surfaces, that is, the distal surface, the proximal surface, a pair of main surfaces, and a pair of side surfaces. and an intersecting ridgeline,
The electrolytic capacitor element according to any one of claims 1 to 6, wherein said second layer covers corners formed by said tip end surfaces.
8. The electrolytic capacitor element according to claim 7, wherein said second layer further covers said tip end face and a ridge portion formed by said tip end face.
9. The electrolytic capacitor element according to claim 7, wherein said second layer further covers each of said side surfaces and a ridge formed by each of said side surfaces.
The electrolytic capacitor element according to any one of claims 1 to 9, wherein said second layer is arranged along said mask layer.