WO2019156120A1

WO2019156120A1 - Electrolytic capacitor

Info

Publication number: WO2019156120A1
Application number: PCT/JP2019/004251
Authority: WO
Inventors: 剛史古川; 智之谷
Original assignee: 株式会社村田製作所
Priority date: 2018-02-08
Filing date: 2019-02-06
Publication date: 2019-08-15
Also published as: JP6919732B2; JPWO2019156120A1

Abstract

Provided is an electrolytic capacitor characterized by comprising a laminate including at least one capacitor element having: anode foil having a dielectric layer on a surface thereof; cathode foil opposed to the anode foil; and a separator which is provided between the anode foil and the cathode foil and in which an electrolyte is immersed or a solid electrolyte is filled, and characterized in that, when a surface of the laminate located in a laminating direction is a principal surface, an extraction surface of the anode foil and the cathode foil are a first side surface, a surface opposed to the first side surface is a second side surface, and surfaces orthogonal to the first side surface and the principal surface are a third side surface and a fourth side surface, edges of the separator located on the first to fourth side surfaces are covered with insulating resin, and at least one of the first to fourth side surfaces of the insulating resin has a cutout.

Description

Electrolytic capacitor

The present invention relates to an electrolytic capacitor.

Patent Document 1 discloses a wound electrolytic capacitor. This electrolytic capacitor uses a solid electrolyte and an electrolyte as an electrolyte.
Since the solid electrolyte is used, the ESR can be lowered, and since the electrolyte is used, the leakage current is small.

Patent Document 2 discloses a multilayer electrolytic capacitor. This electrolytic capacitor uses a solid electrolyte as an electrolyte.
Since a solid electrolyte is used, ESR can be lowered.

JP 2008-10657 A JP 2009-135431 A

The electrolytic capacitor described in Patent Document 1 has characteristics such as low ESR because it uses a solid electrolyte and low leakage current because it uses an electrolytic solution. There was a problem that the layer was stressed and easily cracked, resulting in a leakage current caused by the crack.
On the other hand, since the electrolytic capacitor described in Patent Document 2 is a multilayer type, no stress is applied to the dielectric layer, so that it is difficult to crack. However, since a solid electrolyte is used as the electrolyte, there is a problem that the leakage current increases.

For this reason, in order to obtain an electrolytic capacitor that is difficult to crack in the dielectric layer and has a small leakage current, it is conceivable to use a multilayer electrolytic capacitor using an electrolytic solution.
Therefore, an attempt was made to use an electrolytic solution as an electrolyte in a multilayer electrolytic capacitor.
Specifically, an attempt was made to manufacture an electrolytic capacitor by manufacturing a separator previously immersed in an electrolytic solution and passing through the step of stacking the separator during the manufacture of a multilayer electrolytic capacitor.
However, in this method, since the electrolytic solution evaporates during the manufacturing process, the amount of the electrolytic solution in the separator varies, and as a result, the capacitance may decrease and the capacitance may vary.

In light of the above-described problems, the present invention is a multilayer type, and it is possible to use an electrolytic solution as an electrolyte, and to provide a structure of an electrolytic capacitor that can suppress a decrease in capacitance of the electrolytic capacitor and variations in capacitance. The purpose is to provide.

The electrolytic capacitor of the present invention comprises an anode foil having a dielectric layer on the surface, a cathode foil facing the anode foil, and an electrolyte solution impregnated or filled with a solid electrolyte between the anode foil and the cathode foil. An electrolytic capacitor comprising a laminate including at least one capacitor element having a separator,
The surface located in the stacking direction of the laminate is a main surface, the lead-out surface of the anode foil and the cathode foil is a first side surface,
A surface facing the first side surface is a second side surface;
A surface perpendicular to the first side surface and the main surface is defined as a third side surface and a fourth side surface,
An edge located on the first to fourth side surfaces of the separator is covered with an insulating resin, and at least one of the first to fourth side surfaces of the insulating resin has a notch. It is characterized by that.

According to the present invention, it is possible to provide a structure of an electrolytic capacitor that is a multilayer type, can use an electrolytic solution as an electrolyte, and can suppress a decrease in capacitance of the electrolytic capacitor and variations in capacitance.

FIG. 1 is a perspective view schematically showing a state before a substrate, a laminate, and a case are combined. FIG. 2 is a perspective view schematically showing an example of a substrate on which the laminate is mounted. FIG. 3 is a perspective view schematically showing a state in which the laminate is mounted on the substrate. FIG. 4 is a perspective view schematically showing a state in which the case is covered after the laminated body is mounted on the substrate. FIG. 5 is a perspective view schematically showing an example of a laminated body in which a plurality of capacitor elements are laminated. 6 is an enlarged perspective view showing a part of the third side surface of the laminate shown in FIG. FIG. 7A is a perspective view showing an example of an anode foil unit, and FIG. 7B is a cross-sectional view taken along line AA of the anode foil unit shown in FIG. 7A. FIG. 8A is a perspective view showing an example of the cathode foil unit, and FIG. 8B is a cross-sectional view taken along the line BB of the cathode foil unit shown in FIG. 8A. FIG. 9A is a cross-sectional view schematically showing a capacitor element in which an anode unit and a cathode unit are stacked, and FIG. 9B is a side view of a multilayer body including the capacitor element shown in FIG. It is a perspective view which shows typically an example of the laminated body which formed the connection electrode in. FIG. 10 is a perspective view schematically showing an example of an anode foil sheet. FIG. 11 is a perspective view schematically showing an example of the cathode foil sheet.

Hereinafter, the electrolytic capacitor of the present invention will be described.
However, the present invention is not limited to the following configurations, and can be applied with appropriate modifications without departing from the scope of the present invention. A combination of two or more desirable configurations of the present invention described below is also the present invention.

Each embodiment shown below is an illustration, and it cannot be overemphasized that a partial substitution or combination of composition shown in a different embodiment is possible.

The electrolytic capacitor of the present invention comprises an anode foil having a dielectric layer on the surface, a cathode foil facing the anode foil, and an electrolyte solution impregnated or filled with a solid electrolyte between the anode foil and the cathode foil. An electrolytic capacitor comprising a multilayer body including at least one capacitor element having a separator, wherein a surface located in a stacking direction of the multilayer body is a main surface, and lead-out surfaces of the anode foil and the cathode foil are first side surfaces. The first side surface of the separator is the first side surface of the separator. The second side surface is the surface facing the first side surface, the third side surface and the fourth side surface are orthogonal to the first side surface and the main surface. An edge located on the side surface of the insulating resin is covered with an insulating resin, and at least one of the first to fourth side surfaces of the insulating resin has a notch.

Since the electrolytic capacitor of the present invention is a multilayer electrolytic capacitor in which an anode foil having a dielectric layer on the surface and a cathode foil opposite to the anode foil are stacked, stress is not easily applied to the anode foil and the cathode foil.

In the capacitor element used in the electrolytic capacitor of the present invention, a separator is disposed between the anode foil and the cathode foil, and the insulating resin covering the edge located on the side surface side of the separator laminate has a notch. Since the electrolytic solution can be injected into the separator from this notch and the amount of the electrolytic solution can be accurately controlled, a decrease in the capacitance of the electrolytic capacitor and a variation in the capacitance can be suppressed.
Alternatively, an electrolytic capacitor can be manufactured by a manufacturing method in which a separator in which an electrolytic solution is preliminarily immersed is laminated, and the electrolytic solution is injected into the separator through a notch after the lamination.

As described above, the electrolytic capacitor of the present invention is a multilayer electrolytic capacitor, and is an electrolytic capacitor capable of injecting an electrolytic solution into a separator from a notch. Explained.

First, the basic configuration of the electrolytic capacitor of each embodiment will be described.
The electrolytic capacitor of the present invention includes a laminate including a capacitor element, a substrate, and a case.
In this electrolytic capacitor, the electrode of the laminate and the electrode of the substrate are joined, and the case and the substrate are joined so as to accommodate the laminate.
The overall structure of the electrolytic capacitor will be described with reference to FIGS.

FIG. 1 is a perspective view schematically showing a state before a substrate, a laminate, and a case are combined.
FIG. 2 is a perspective view schematically showing an example of a substrate on which the laminate is mounted.
FIG. 3 is a perspective view schematically showing a state in which the laminate is mounted on the substrate.
FIG. 4 is a perspective view schematically showing a state in which the case is covered after the laminated body is mounted on the substrate.

FIG. 1 shows a state before the substrate 400, the laminate 100, and the case 500 are combined. First, the case 500 and the substrate 400 and the overall structure in which the substrate 400, the laminate 100, and the case 500 are combined will be described.
A detailed description of the structure of the laminate 100 will be described later.

FIG. 1 shows a case 500 for housing the laminate 100 and sealing the laminate 100 together with the substrate 400. The case is box-shaped and made of resin. As the material of the case, metal or ceramic can be used. The sealing method uses a sealing material to join the substrate and the case. When using a metal case, it can also be sealed using welding.

FIG. 2 shows a substrate 400 on which the stacked body 100 is mounted and connected to an external circuit.
The substrate 400 is a substrate in which conductors are formed on both surfaces, and an anode external electrode 410 and a cathode external electrode 420 as surface external electrodes are formed on the surface of the insulating substrate 430 (surface visible in the figure).
An anode external electrode and a cathode external electrode as back external electrodes connected to an external circuit are formed on the back surface (surface not shown in the figure) of the insulating substrate 430 facing the surface of the insulating substrate 430.

The anode external electrode formed on the front surface of the substrate 400 and the anode external electrode formed on the back surface are electrically connected by a plurality of connection conductors 411. The cathode external electrode formed on the front surface of the substrate 400 and the cathode external electrode formed on the back surface are electrically connected by a plurality of connection conductors 421. Since an external electrode is formed on the back surface of the substrate 400, the back surface external electrode can be used to connect to the circuit board.
Further, as a modification, an electrode may be formed on the side surface of the substrate, and conduction between the front surface external electrode and the back surface external electrode may be established through the electrode.

FIG. 3 shows a state in which the stacked body 100 is mounted on the substrate 400.
The anode external electrode 410 on the surface of the substrate 400 and the anode connection electrode of the laminate 100 are connected by soldering, and the cathode external electrode 420 on the surface of the substrate 400 and the cathode connection electrode of the laminate 100 are connected by soldering. The corresponding surfaces are facing each other.
Moreover, it can also join using a conductive adhesive as another joining method. Further, without forming the connection electrode, the anode foil and the cathode foil lead-out portion and the surface external electrode of the substrate may be joined directly with the conductive adhesive.

In the substrate 400 shown in FIGS. 1 and 3, a resin sealing material 440 is formed around the substrate 400. The sealing material is made of a thermoplastic resin.
In the laminated body 100, the connection electrode is placed downward, and the connection electrode of the laminated body and the surface external electrode of the substrate face each other.

The connection electrode of the laminate and the surface external electrode of the substrate are joined by soldering.
The connection electrode of the laminate will be described later. The anode connection electrode is an anode foil, and the cathode connection electrode is an electrode electrically connected to the cathode foil.

FIG. 4 shows a state in which the case 500 is covered after the stacked body 100 is mounted on the substrate 400.
A case 500 is placed on the laminate 100 mounted on the substrate 400, and a thermoplastic resin sealing material 440 provided around the substrate 400 is sandwiched between the case 500 and the substrate 400 to be heated and cooled. As a result, the case 500 and the substrate 400 are joined to seal the stacked body 100.
The overall structure of the electrolytic capacitor is as described above.

Such an electrolytic capacitor is an electrolytic capacitor that can be surface mounted using the anode external electrode and the cathode external electrode on the back surface of the substrate.
Since the anode external electrode and the cathode external electrode on the back surface of the substrate are flat electrodes, they are suitable for surface mounting.

Next, the laminated body used for an electrolytic capacitor is demonstrated.
As specific embodiments of the laminated body, there are several embodiments to be described later. First, matters common to the embodiments will be described.
The presence or absence of the solid electrolyte layer provided on the surfaces of the anode foil and the cathode foil differs depending on the embodiment, but an example in which the solid electrolyte layer is provided on the surfaces of the anode foil and the cathode foil will be described below.
FIG. 5 is a perspective view schematically showing an example of a laminated body in which a plurality of capacitor elements are laminated.
The laminated body 100 includes a first main surface M101 and a second main surface M102 that face each other in the stacking direction (T direction), a first side surface S101 that is an electrode extraction surface of the anode foil and the cathode foil, and a first side surface S101. Second side surface S102 facing in the width direction (W direction), and third side surface S103 and the second side surface S103 facing in the length direction (L direction) orthogonal to the first side surface S101 and first main surface M101. It has four side surfaces S104.
In addition, the “side surface” in this specification means a surface other than the main surface facing in the stacking direction. And in the laminated body used for the electrolytic capacitor of this invention, it has a notch in at least 1 of the insulating resin which covers the edge located in the side surface side of the laminated body of a separator.

On the first side S101, the anode foil 10 and the cathode foil 20 are drawn on the same side, and in FIG. 5, a cathode lead-out portion is provided on the left side of the drawing and an anode lead-out portion is provided on the right side.
In the first side surface S101, portions other than the anode foil 10 and the cathode foil 20 are the insulating resin 14, the insulating resin 24, or the sealing material 54. The sealing material 54 is also an insulating material.
The cathode lead portion and the anode lead portion can be provided with a connection electrode that is electrically connected to an external electrode on the substrate. Details of the connection electrode will be described later.

6 is an enlarged perspective view showing a part of the third side surface of the laminate shown in FIG.
The third side surface S103 of the laminate 100 has an insulating resin 14 that covers the edge of the separator and a notch 15 in which a part of the insulating resin 14 is cut out. In addition, the third side surface S103 of the laminate 100 includes an insulating resin 24 that covers the edge of the separator and a notch 25 in which a part of the insulating resin 24 is cut out.
FIG. 6 schematically shows a state where the separator can be seen from the notch of the insulating resin.

The separator 30 on the anode foil 10 is partially covered with the insulating resin 14, and a part of the edge is exposed from the notch 15 of the insulating resin 14 to the third side surface S 103. ing.
The separator 40 on the cathode foil 20 is partially covered with the insulating resin 24, and a part of the edge is exposed from the notch 25 of the insulating resin 24 to the third side surface S 103. ing.
The anode foil 10 and the cathode foil 20 are laminated via the

separators

30 and 40, and the edges of the

separators

30 and 40 are exposed through the insulating

resin notches

15 and 25 from the third side surface S103.
A space is provided between the

separators

30 and 40 and the third side surface S103 by the

notches

15 and 25 of insulating resin. Therefore, the electrolytic solution can be injected into the

separators

30 and 40 from the

notches

15 and 25, and the amount of the electrolytic solution can be adjusted after lamination. After injecting the electrolytic solution from the notch, a layered body is obtained by covering portions other than the lead-out portion of the connection electrode with a resin (not shown).
The shape, size and arrangement of the notches are not particularly limited, and can be determined in consideration of the injection efficiency of the electrolytic solution and the adhesion reliability of the insulating resin.

FIG. 7A is a perspective view showing an example of an anode foil unit, and FIG. 7B is a cross-sectional view taken along line AA of the anode foil unit shown in FIG. 7A.
The anode foil unit 1 has a cross-sectional structure as shown in FIG. 7B, and is centered on an anode foil 10 including a valve metal base 11 and a dielectric layer 12 formed on both surfaces of the valve metal base. Thus, the solid electrolyte layer 13 is provided on the surface of the dielectric layer 12. In FIG. 7A, illustration of the valve action metal substrate 11, the dielectric layer 12, and the solid electrolyte layer 13 is omitted, and the anode foil 10 is shown.
And the separator 30 is arrange | positioned on the solid electrolyte layer 13 shown to the upper side of FIG.7 (b). As a basic configuration of the electrolytic capacitor of the present invention, the solid electrolyte layer 13 on the anode foil 10 is not essential, and may be omitted as in the embodiments described later.
In addition, it is preferable that a porous layer (not shown in FIG. 7B) is formed on both surfaces of the valve metal base 11, and a dielectric layer 12 is provided on the surface of the porous layer. It is more preferable.

As shown in FIG. 7A, an insulating resin 14 is provided around the separator 30.
Edges 30S1 and 30S2 of the separator 30 are covered with insulating resins 14S1 and 14S2, respectively.
A part of the edge 30S3 of the separator 30 is covered with an insulating resin 14S3 having a periodic shape. As a periodic shape, the insulating resin 14S3 has notches 15 at regular intervals and has a comb-like structure. As a result, a part of the separator 30 is exposed in a periodic arrangement on the side surface of the laminate. One such anode foil unit may be included in the laminate, or a plurality of anode foil units may be included. Further, the notches may be arranged at indefinite intervals.
A part of the edge 30S4 of the separator 30 is similarly covered with a periodic insulating resin 14S4.

The anode foil 10 is exposed on the right side of the first side surface side 10S1, so that the anode foil 10 can be pulled out. Further, a sealing material 54 is provided in a columnar shape on a part of the right side of the first side surface 10S1. On the other hand, the anode foil 10 is covered with the sealing material 54 on the left side of the first side surface 10S1.
The cross-sectional view shown in FIG. 7B shows a state where the edge 30S3 of the separator 30 is not covered with the insulating resin 14S3 and the edge 30S4 of the separator 30 is covered with the insulating resin 14S4. .
It should be noted that a part of the insulating resin 14S1 and 14S2 covering the separator edges 30S1 and 30S2 is provided with a notch 15 so that a part of the separator edge 30S1 or 30S2 is exposed on the side surface of the laminate. Also good.
Moreover, what is necessary is just to expose the edge of a separator in any one side surface of a laminated body by providing a notch in a part of insulating resin which covers the edge of a separator.

FIG. 8A is a perspective view showing an example of the cathode foil unit, and FIG. 8B is a cross-sectional view taken along the line BB of the cathode foil unit shown in FIG. 8A.
The cathode foil unit 2 has a cross-sectional structure as shown in FIG. 8B, and solid electrolyte layers 23 are provided on both surfaces of the cathode foil 20 with the cathode foil 20 as the center.
And the separator 40 is arrange | positioned on the solid electrolyte layer 23 shown to the upper side of FIG.8 (b). As a basic configuration of the electrolytic capacitor of the present invention, the solid electrolyte layer 23 on the cathode foil 20 is not essential, and may be omitted as in the embodiments described later.

As shown in FIG. 8A, an insulating resin 24 is provided around the separator 40.
The edges 40S1 and 40S2 of the separator 40 are covered with insulating resins 24S1 and 24S2, respectively.
A part of the edge 40S3 of the separator 40 is covered with an insulating resin 24S3 having a periodic shape. As a periodic shape, the insulating resin 24S3 has a notch 25 at regular intervals and has a comb-like structure. As a result, a part of the separator 40 is exposed in a periodic arrangement on the side surface of the laminate. One such cathode foil unit may be included in the laminate, or a plurality of cathode foil units may be included. Further, the notches may be arranged at indefinite intervals.
A part of the edge 40S4 of the separator 40 is similarly covered with the insulating resin 24S4.

The cathode foil 20 is exposed on the left side of the first side surface 20S1 so that the cathode foil 20 can be pulled out. Further, a sealing material 54 is provided in a columnar shape on a part of the left side of the first side surface side 20S1. On the other hand, the cathode foil 20 is covered with a sealing material 54 on the right side of the first side face 20S1.
The cross-sectional view shown in FIG. 8B shows a state where the edge 40S3 of the separator 40 is not covered with the insulating resin 24S3 and the edge 40S4 of the separator 40 is covered with the insulating resin 24S4. .
A part of the insulating resin 24S1, 24S2 covering the separator edges 40S1, 40S2 is provided with a notch 25 so that a part of the separator edge 40S1, 40S2 is exposed on the side surface of the laminate. Also good.
Moreover, what is necessary is just to expose the edge of a separator in any one side surface of a laminated body by providing a notch in a part of insulating resin which covers the edge of a separator.

As a separator, what consists of paper, a nonwoven fabric, a porous film etc. can be used, for example. Examples of the material constituting the separator include cellulose, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, nylon, aromatic polyamide, polyimide, polyamideimide, polyetherimide, rayon, and glass.
The thickness of the separator is preferably 5 μm or more, and preferably 100 μm or less.
ESR can be reduced by reducing the thickness of the separator.
As shown in FIGS. 7A and 8A, when a separator is provided on each of the anode foil and the cathode foil, the separator and the separator provided on the anode foil and the cathode foil have the same material and thickness. Or may be different.

The anode foil and the cathode foil are made of a valve metal that exhibits a so-called valve action. Examples of the valve action metal include simple metals such as aluminum, tantalum, niobium, titanium, and zirconium, and alloys containing these metals. Among these, aluminum or tantalum is preferable. The valve action metal constituting the cathode foil is preferably the same as the valve action metal constituting the anode foil, but may be different.
The anode foil is preferably a single metal of aluminum.

The dielectric layer formed on the surface of the anode foil is preferably made of an oxide film of the valve action metal. For example, when an aluminum foil is used as the anode foil, a dielectric layer made of an oxide film can be formed by anodizing the surface of the aluminum foil in an aqueous solution containing ammonium adipate or the like.

The surface of the cathode foil is preferably roughened by etching or the like to be porous. In addition, a very thin dielectric layer may be formed on the surface of the cathode foil as compared with the dielectric layer formed on the surface of the anode foil.

Examples of the material constituting the solid electrolyte layer include conductive polymers such as polypyrroles, polythiophenes, and polyanilines. Among these, polythiophenes are preferable, and poly (3,4-ethylenedioxythiophene) called PEDOT is particularly preferable. The conductive polymer may contain a dopant such as polystyrene sulfonic acid (PSS). The solid electrolyte layer preferably includes an inner layer that fills the pores (recesses) of the dielectric layer and an outer layer that covers the dielectric layer.

Examples of the insulating resin include polyphenylsulfone resin, polyethersulfone resin, cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, etc.), soluble polyimide siloxane and epoxy resin. Insulating resins such as compositions, polyimide resins, polyamideimide resins, and derivatives or precursors thereof.

As the sealing material, a resin is used, and a filler is included as necessary.
Examples of the resin contained in the sealing material include an epoxy resin and a phenol resin. Moreover, as a filler contained in a sealing material, a silica particle, an alumina particle, a metal particle etc. are mentioned, for example.

The electrolyte to be injected into the separator is obtained by dissolving an acid or base electrolyte in a solvent. Examples of the solvent include glycols such as ethylene glycol (C ₂ H ₆ O ₂ ), lactones such as γ-butyrolactone (C ₄ H ₆ O ₂ ), and sulfones such as sulfolane (C ₄ H ₈ O ₂ S). Is mentioned. Examples of the acid for the electrolyte include aliphatic carboxylic acids such as adipic acid (C ₆ H ₁₀ O ₄ ) and aromatic carboxylic acids such as phthalic acid (C ₈ H ₆ O ₂ ). Examples of the electrolyte base include amines such as ammonia (NH ₃ ) and triethylamine (C ₆ H ₁₅ N), and amidines such as tetramethylimidazolinium (C ₇ H ₁₅ N ₂ ).

Examples of the resin covering the laminate include an epoxy resin and a phenol resin.

The laminated body 100 which comprises the electrolytic capacitor of this invention contains the capacitor | condenser element. FIG. 9A is a cross-sectional view schematically showing a capacitor element in which the anode unit 1 and the cathode unit 2 are stacked. An anode foil 10 having a dielectric layer 12 on the porous surface of the valve action metal substrate 11, a cathode foil 20 facing the anode foil 10, a separator 30 disposed between the anode foil 10 and the

cathode foil

20, 40 constitutes the capacitor element 5.
In the capacitor element in which the cathode unit 2 is stacked on the anode unit 1, the separator 30 is disposed between the anode foil 10 and the cathode foil 20. The capacitor element in which the anode unit 1 is stacked on the cathode unit 2. Then, the separator 40 is disposed between the cathode foil 20 and the anode foil 10.

FIG. 9B is a perspective view schematically showing an example of a laminated body in which connection electrodes are formed on the side surfaces of the laminated body including the capacitor element shown in FIG.

FIG. 9B shows a state in which the anode connection electrode 310 and the cathode connection electrode 320 are formed on the first side face S101 of the multilayer body 100 in which the capacitor elements are laminated.
The anode connection electrode 310 and the cathode connection electrode 320 will be described.

The anode connection electrode 310 is connected to a plurality of anode foil leads drawn out to the side surface of the laminate 100, and the cathode connection electrode 320 is connected to a plurality of cathode foil leads drawn out to the side surface of the laminate 100. Yes. The anode connection electrode 310 and the cathode connection electrode 320 have a first conductive film, a second conductive film, and a third conductive film. The first conductive film is formed of a Zn plating film, the second conductive film is formed of a Ni plating film, and the third conductive film is formed of a Sn plating film. The Pd plating film may be in the first conductive film.
Further, the first conductive film is preferably a metal having good connectivity with the anode foil and the cathode foil. When the anode foil and the cathode foil are aluminum, it is preferable to use a Zn plating film as the first conductive film.
Note that the connection electrode may be a single conductive film or a plurality of conductive films.

FIG. 9B illustrates a stacked body in which connection electrodes are formed, but a stacked body in which connection electrodes are not formed may be used. In the case of using a laminate in which no connection electrode is formed, the anode foil and cathode foil lead-out portion and the anode external electrode and cathode external electrode on the surface of the substrate may be joined directly with a conductive adhesive.

The laminated body shown in FIG. 5 constituting the electrolytic capacitor of the present invention can be manufactured, for example, by the following method.
FIG. 10 is a perspective view schematically showing an example of the anode foil sheet, and FIG. 11 is a perspective view schematically showing an example of the cathode foil sheet.
The anode foil sheet 201 shown in FIG. 10 is provided with a large number of parts to be the anode foil unit 1 shown in FIG. 7A, and a large number of anode foil units are obtained by cutting the anode foil sheet 201 at predetermined positions. be able to.
The cathode foil sheet 202 shown in FIG. 11 is provided with many parts to be the cathode foil unit 2 shown in FIG. 8A, and a large number of cathode foil units are obtained by cutting the cathode foil sheet 202 at predetermined positions. be able to.
In FIG.10 and FIG.11, the cutting scheduled position of the anode foil sheet 201 and the cathode foil sheet 202 is shown with the dashed-dotted line.

The anode foil sheet 201 is provided with a first through hole H1 and a second through hole H2 at a planned cutting position on the side surface from which the anode foil of the anode foil unit 1 is drawn.
The cathode foil sheet 202 is provided with a third through hole H3 and a fourth through hole H4 at a planned cutting position on the side surface from which the cathode foil of the cathode foil unit 2 is drawn.
The first through hole H1 and the fourth through hole H4 have a long hole shape, and the second through hole H2 and the third through hole H3 have a substantially round hole shape.
Each through hole is formed by, for example, laser processing, etching processing, punching processing, or the like.

By laminating such anode foil sheet 201 and cathode foil sheet 202 alternately, a laminated sheet is produced.
In the obtained laminated sheet, the first through hole H1 and the third through hole H3, and the second through hole H2 and the fourth through hole H4 are communicated with each other in the laminating direction.
Lamination is performed by filling the first through hole and the third through hole, and the second through hole and the fourth through hole with the sealing material 54 from at least one main surface side of the obtained laminated sheet. A block body is produced.

The manufactured laminated block body is heat-treated. By performing the heat treatment, the insulating resin and the sealing material are cured, and the anode foil and the cathode foil are integrated.

The heat-treated laminated block body is cut at the scheduled cutting positions of the anode foil sheet 201 and the cathode foil sheet 202 shown in FIGS.

The filled sealing material 54 is cut into approximately half so as to be exposed at the first side face S101 of the laminate 100. As a result, a laminate 100 as shown in FIG. 5 is obtained.
On the first side face S101 of the laminate 100, the anode foil 10 is exposed on the right side, and the cathode foil 20 is exposed on the left side. And in 1st side surface S101, the right side turns into the drawer part of anode foil, and the left side becomes the drawer part of cathode foil.

Next, an electrolytic solution is injected into the

separators

30 and 40 from the

notches

15 and 25. The electrolyte solution can be injected while adjusting the injection amount. For example, the amount of the necessary electrolyte is specified, the total weight of the laminate is obtained, and the electrolyte is injected while measuring the weight of the laminate so that the total weight is obtained.
Since the electrolytic solution is injected into the

separators

30 and 40 after the heat treatment for curing the insulating resin and the sealing material, the amount of the electrolytic solution in the separator decreases or varies due to the evaporation of the electrolytic solution due to the heat of the heat treatment. Never do.
Next, a resin is applied to portions other than the lead-out portion of the laminate 100 in which the electrolytic solution is injected into the

separators

30 and 40, particularly the portions of the

notches

15 and 25.
Thereby, when forming a connection electrode in the extraction part of an anode foil and the extraction part of a cathode foil in a next process, the inside of a laminated body can be protected or evaporation of an electrolyte can be prevented.
Next, connection electrodes are formed on the lead-out portion of the anode foil on the right side toward the first side surface S101 and the lead-out portion on the left side of the cathode foil.

The connection electrode is obtained by plating a conductive film on the exposed portions of the anode foil and the cathode foil exposed on the side surface of the laminate. For example, it can be performed by the following procedure.
First, the oil on the surface of the laminate is removed with an alkali treatment agent. Next, the exposed oxide film of the anode foil and the cathode foil is removed by alkali etching. Next, the smut of the exposed part of anode foil and cathode foil is removed by smut removal treatment. Next, Zn is substituted and deposited by zincate treatment to form a Zn metal film as a first conductive film on the exposed portions of the anode foil and the cathode foil. Next, a Ni metal film is formed as a second conductive film on the first conductive film by Ni plating. Further, an Sn metal film is formed as a third conductive film on the second conductive film by Sn plating.
Below, the characteristic is demonstrated for every specific embodiment of a laminated body.

(First embodiment)
The laminate used for the electrolytic capacitor according to the first embodiment of the present invention is formed by stacking an anode unit and a cathode unit. This laminate has a solid electrolyte layer between the anode foil and the separator and between the cathode foil and the separator. Further, the separator is impregnated with an electrolytic solution and is not filled with a solid electrolyte.
In the electrolytic capacitor of the first embodiment, electrons are usually exchanged between the anode foil and the cathode foil via the solid electrolyte layer on the anode side, the electrolyte in the separator, and the solid electrolyte layer on the cathode side. On the other hand, when there is no electrolyte impregnated in the separator, electrons are not transferred in the thickness direction of the separator, so the failure mode is an open mode. Therefore, a highly safe electrolytic capacitor can be obtained.

Further, as a modification of the laminate used in the electrolytic capacitor according to the first embodiment of the present invention, a solid electrolyte layer is provided between one of the anode foil and the separator and between the cathode foil and the separator. On the other hand, the form which does not have a solid electrolyte layer is mentioned.
Also in this case, since the failure mode when the electrolyte solution impregnated in the separator disappears is an open mode, an electrolytic capacitor with high safety is obtained.
Since the electrolytic capacitor of the present embodiment is a multilayer type, the dielectric layer is not easily cracked, and the electrolytic solution can be injected into the separator from the notch, so that the amount of the electrolytic solution in the separator decreases or varies. Therefore, it is possible to suppress a decrease or variation in capacitance.

(Second Embodiment)
The laminate used for the electrolytic capacitor according to the second embodiment of the present invention is formed by stacking an anode unit and a cathode unit. This laminate does not have a solid electrolyte layer between the anode foil and the separator and between the cathode foil and the separator. Further, the separator is impregnated with an electrolytic solution and is not filled with a solid electrolyte.
In the electrolytic capacitor of the second embodiment, electrons are usually exchanged between the anode foil and the cathode foil through only the electrolyte solution in the separator. On the other hand, when no electrolyte is impregnated in the separator, electrons are not exchanged in the thickness direction of the separator, so the failure mode is an open mode. Therefore, a highly safe electrolytic capacitor can be obtained.
Since the electrolytic capacitor of the present embodiment is a multilayer type, the dielectric layer is not easily cracked, and the electrolytic solution can be injected into the separator from the notch, so that the amount of the electrolytic solution in the separator decreases or varies. Therefore, it is possible to suppress a decrease or variation in capacitance.

(Third embodiment)
The laminate used for the electrolytic capacitor according to the third embodiment of the present invention is formed by stacking an anode unit and a cathode unit. This laminate does not have a solid electrolyte layer between the anode foil and the separator and between the cathode foil and the separator. The separator is filled with a solid electrolyte containing a conductive polymer, but is not impregnated with an electrolytic solution.
Filling the separator with the solid electrolyte is performed by immersing the separator in a dispersion in which conductive polymer particles and a solvent are mixed, then drying the separator to evaporate the solvent, and the separator contains the conductive polymer. Can be carried out by filling. The separator is filled with the solid electrolyte before the separator is placed on the anode foil or the cathode foil.
In the electrolytic capacitor of the third embodiment, electrons are usually exchanged between the anode foil and the cathode foil only through the solid electrolyte filled in the separator.
Since the electrolytic capacitor of this embodiment is a multilayer type, it is difficult for the dielectric layer to crack.

(Fourth embodiment)
The laminate used for the electrolytic capacitor according to the fourth embodiment of the present invention is formed by stacking an anode unit and a cathode unit. This laminate does not have a solid electrolyte layer between the anode foil and the separator and between the cathode foil and the separator. The separator is filled with a solid electrolyte containing a conductive polymer and impregnated with an electrolytic solution. Filling the separator with the solid electrolyte is performed by the same method as in the third embodiment.
In the present embodiment, the separator is filled with a solid electrolyte containing a conductive polymer, and the separator is impregnated with an electrolytic solution.
In the electrolytic capacitor of the fourth embodiment, electrons are usually exchanged between the anode foil and the cathode foil via the solid electrolyte filled in the separator and the electrolyte in the separator.
Since the electrolytic capacitor of the present embodiment is a multilayer type, the dielectric layer is not easily cracked, and the electrolytic solution can be injected into the separator from the notch, so that the amount of the electrolytic solution in the separator decreases or varies. Therefore, it is possible to suppress a decrease or variation in capacitance.

(Fifth embodiment)
The laminate used for the electrolytic capacitor according to the fifth embodiment of the present invention is formed by stacking an anode unit and a cathode unit. This laminate has a solid electrolyte layer between the anode foil and the separator and between the cathode foil and the separator. The separator is filled with a solid electrolyte containing a conductive polymer and impregnated with an electrolytic solution. Filling the separator with the solid electrolyte is performed by the same method as in the third embodiment.
The electrolytic capacitor of the fifth embodiment normally transfers electrons between the anode foil and the cathode foil via the solid electrolyte layer on the anode side—the electrolyte in the separator and the solid electrolyte in the separator—the solid electrolyte layer on the cathode side. Is done.
Since the electrolytic capacitor of the present embodiment is a multilayer type, the dielectric layer is not easily cracked, and the electrolytic solution can be injected into the separator from the notch, so that the amount of the electrolytic solution in the separator decreases or varies. Therefore, it is possible to suppress a decrease or variation in capacitance.

(Sixth embodiment)
The laminate used for the electrolytic capacitor according to the sixth embodiment of the present invention is formed by stacking an anode unit and a cathode unit. This laminate has a solid electrolyte layer between the anode foil and the separator and between the cathode foil and the separator. The separator is filled with a solid electrolyte containing a conductive polymer, but is not impregnated with an electrolytic solution. Filling the separator with the solid electrolyte is performed by the same method as in the third embodiment.
In the electrolytic capacitor of the sixth embodiment, electrons are usually exchanged between the anode foil and the cathode foil via the solid electrolyte layer on the anode side-the solid electrolyte in the separator-the solid electrolyte layer on the cathode side.
Since the electrolytic capacitor of this embodiment is a multilayer type, it is difficult for the dielectric layer to crack.

The electrolytic capacitor of the present invention described so far is a surface mountable electrolytic capacitor.
That is, the electrolytic capacitor of the present invention includes an electrolytic capacitor having the following characteristics.
In the following electrolytic capacitors, the backside external electrode is exposed as a flat electrode on the outer peripheral surface of the electrolytic capacitor, so that the electrolytic capacitor can be mounted by surface mounting using the backside external electrode.

[1] an anode foil having a dielectric layer on the surface;
A cathode foil facing the anode foil;
An electrolytic capacitor comprising a laminate including at least one capacitor element having a separator impregnated with an electrolytic solution or filled with a solid electrolyte between the anode foil and the cathode foil,
A substrate having a front surface anode external electrode and a front surface cathode external electrode as a front surface external electrode on one surface, and a back surface anode external electrode and a back surface cathode external electrode as a back surface external electrode on the other surface facing the one surface, respectively. When,
A case for accommodating the laminate,
The anode foil and the cathode foil are drawn out to the first side surface of the laminate,
The anode foil is connected to an anode external electrode on the surface of the substrate; the cathode foil is connected to a cathode external electrode on the surface of the substrate;
The case is characterized in that the case accommodates the laminated body and is bonded to the substrate.

[2] The laminate has an anode connection electrode connected to the anode foil and a cathode connection electrode connected to the cathode foil on the first side surface,
The electrolysis according to [1], wherein the anode connection electrode is connected to an anode external electrode on the surface of the substrate, and the cathode connection electrode is connected to a cathode external electrode on the surface of the substrate. Capacitor.

[3] The electrolytic capacitor as described in [2] above, wherein the anode connection electrode and the cathode connection electrode have plating films.

[4] The electrolytic capacitor as described in [3] above, wherein the plating film includes a plurality of films.

[5] The electrolytic capacitor as described in [3] or [4] above, wherein the plating film includes a Zn plating film made of Zn.

[6] The electrolytic capacitor as described in [5] above, wherein the plating film includes a Ni plating film made of Ni.

[7] The electrolytic capacitor as described in [5] or [6] above, wherein the plating film includes a Sn plating film made of Sn.

[8] The connection between the anode connection electrode and the anode external electrode on the surface of the substrate and the connection between the cathode connection electrode and the cathode external electrode on the surface of the substrate are performed by soldering. The electrolytic capacitor according to any one of [1] to [7].

[9] The connection between the anode connection electrode and the anode external electrode on the surface of the substrate and the connection between the cathode connection electrode and the cathode external electrode on the surface of the substrate are performed through a conductive adhesive. The electrolytic capacitor as described in any one of [1] to [7] above.

[10] The connection between the anode foil and the anode external electrode on the surface of the substrate and the connection between the cathode foil and the cathode external electrode on the surface of the substrate are made through a conductive adhesive. The electrolytic capacitor as described in [1] above, which is characterized.

[11] The conduction between the anode external electrode on the front surface of the substrate and the anode external electrode on the back surface of the substrate and the conduction between the cathode external electrode on the surface of the substrate and the cathode external electrode on the back surface of the substrate are performed by a plurality of connection conductors. The electrolytic capacitor according to any one of [1] to [10], wherein the electrolytic capacitor is taken.

[12] The electrolytic capacitor according to any one of [1] to [11], wherein the substrate and the case are joined together by a sealing material made of a thermoplastic resin.

DESCRIPTION OF SYMBOLS 1 Anode foil unit 2 Cathode foil unit 5 Capacitor element 10 Anode foil 11 Valve action metal base body 12

Dielectric layer

13, 23

Solid electrolyte layer

14, 24

Insulation resin

15, 25 Notch 20

Cathode foil

30, 40 Separator 54 Sealing material DESCRIPTION OF SYMBOLS 100 Laminated body 201 Anode foil sheet 202 Cathode foil sheet 310 Anode connection electrode 320 Cathode connection electrode 400 Substrate 410 Anode

external electrode

411, 421 Connection conductor 420 Cathode external electrode 430 Insulating substrate 440 Sealing material 500 Case

Claims

An anode foil having a dielectric layer on the surface;
A cathode foil facing the anode foil;
An electrolytic capacitor comprising a laminate including at least one capacitor element having a separator impregnated with an electrolytic solution or filled with a solid electrolyte between the anode foil and the cathode foil,
The surface located in the stacking direction of the laminate is a main surface, the lead-out surface of the anode foil and the cathode foil is a first side surface,
A surface facing the first side surface is a second side surface;
A surface perpendicular to the first side surface and the main surface is defined as a third side surface and a fourth side surface,
An edge located on the first to fourth side surfaces of the separator is covered with an insulating resin, and at least one of the first to fourth side surfaces of the insulating resin has a notch. Electrolytic capacitor.
The electrolytic capacitor according to claim 1, wherein the separator is impregnated with an electrolytic solution.
The electrolytic capacitor according to claim 1, wherein the separator is filled with a solid electrolyte.
The electrolytic capacitor according to claim 1, wherein the separator is impregnated with an electrolytic solution and filled with a solid electrolyte.
The electrolytic capacitor according to claim 1, wherein the separator is impregnated with an electrolytic solution and is not filled with a solid electrolyte.
The electrolytic capacitor according to claim 1, wherein the separator is filled with a solid electrolyte and is not impregnated with an electrolytic solution.
The electrolytic capacitor according to claim 1, further comprising a solid electrolyte layer between the dielectric layer of the anode foil and the separator.
The electrolytic capacitor according to claim 1, further comprising a solid electrolyte layer between the cathode foil and the separator.
The anode foil has a solid electrolyte layer between the dielectric layer and the separator, and between the cathode foil and the separator, and the separator is impregnated with an electrolyte solution, The electrolytic capacitor according to claim 1, which is not filled.
10. The electrolytic capacitor according to claim 1, wherein the notches of the insulating resin are arranged periodically.
Furthermore, the substrate that is mounted on the laminate and electrically connected to the anode foil and the cathode foil that is drawn out to the first side surface of the laminate, and the substrate that accommodates the laminate, 11. The electrolytic capacitor according to claim 1, wherein the electrolytic capacitor has a joined case.