JPWO2019156120A1 - Electrolytic capacitor - Google Patents

Abstract

At least one having an anode foil having a dielectric layer on its surface, a cathode foil facing the anode foil, and a separator impregnated with an electrolytic solution or filled with a solid electrolyte between the anode foil and the cathode foil. An electrolytic capacitor including a laminate including a capacitor element, the surface of the laminate being located in the stacking direction as a main surface, the anode foil and the extraction surface of the cathode foil as a first side surface, and the first side surface. The surface facing the surface is the second side surface, the surface orthogonal to the first side surface and the main surface is the third side surface and the fourth side surface, and the ends of the separator located on the first to fourth side surface sides. An electrolytic capacitor whose edge is covered with an insulating resin and has a notch at at least one of the first to fourth side surfaces of the insulating resin.

Description

The present invention relates to electrolytic capacitors.

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

Patent Document 2 discloses a multilayer electrolytic capacitor. This electrolytic capacitor uses a solid electrolyte as an electrolyte.
Since it uses a solid electrolyte, it has the property of being able to lower the ESR.

Japanese Unexamined Patent Publication No. 2008-10657 Japanese Unexamined Patent Publication No. 2009-135431

The electrolytic capacitor described in Patent Document 1 has the characteristics of low ESR because it uses a solid electrolyte and low leakage current because it uses an electrolytic solution, but it is a dielectric because it is a wound type. There is a problem that the layer is stressed and easily cracked, and a leakage current is generated due to the crack.
On the other hand, since the electrolytic capacitor described in Patent Document 2 is a laminated type, stress is not applied to the dielectric layer, so that cracks are unlikely to occur. However, since a solid electrolyte is used as the electrolyte, there is a problem that the leakage current becomes large.

For this reason, in order to obtain an electrolytic capacitor in which the dielectric layer is less likely to crack and the leakage current is small, it is conceivable to use an electrolytic capacitor that is a laminated type and uses an electrolytic solution.
Therefore, we tried to use an electrolytic solution as an electrolyte in a laminated electrolytic capacitor.
Specifically, an attempt was made to manufacture an electrolytic capacitor by producing a separator immersed in an electrolytic solution in advance and undergoing a step of stacking the separator at the time of manufacturing a laminated 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 or the capacitance may vary.

Based on the above problems, the present invention has a structure of an electrolytic capacitor which is a laminated type, can use an electrolytic solution as an electrolyte, and can suppress a decrease in the capacitance of the electrolytic capacitor and a variation in the capacitance. The purpose is to provide.

The electrolytic capacitor of the present invention is impregnated with an electrolytic solution or filled with a solid electrolyte between an anode foil having a dielectric layer on its surface, a cathode foil facing the anode foil, and the anode foil and the cathode foil. An electrolytic capacitor including a laminate including at least one capacitor element having a separator.
The surface of the laminate in the stacking direction is the main surface, and the anode foil and the extraction surface of the cathode foil are the first surfaces.
The surface facing the first side surface is referred to as the second side surface.
The first side surface and the surface orthogonal to the main surface are defined as the third side surface and the fourth side surface.
The edges of the separator located on the first to fourth side surface sides are 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 which is a laminated type, can use an electrolytic solution as an electrolyte, and can suppress a decrease in the capacitance of the electrolytic capacitor and variation in the capacitance.

FIG. 1 is a perspective view schematically showing a state before combining the substrate, the laminate, and the case. FIG. 2 is a perspective view schematically showing an example of a substrate on which a laminated body is mounted. FIG. 3 is a perspective view schematically showing a state in which the laminated body is mounted on the substrate. FIG. 4 is a perspective view schematically showing a state in which the laminated body is mounted on the substrate and then covered with the case. FIG. 5 is a perspective view schematically showing an example of a laminated body in which a plurality of capacitor elements are laminated. FIG. 6 is an enlarged perspective view showing a part of the third side surface of the laminated body shown in FIG. FIG. 7A is a perspective view showing an example of the anode foil unit, and FIG. 7B is a 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 sectional view taken along line BB of the cathode foil unit shown in FIG. 8A. FIG. 9A is a cross-sectional view schematically showing a capacitor element formed by stacking an anode unit and a cathode unit, and FIG. 9B is a side surface of a laminated body including the capacitor element shown in FIG. 9A. 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 the 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 appropriately modified and applied without changing the gist of the present invention. It should be noted that a combination of two or more desirable configurations of the present invention described below is also the present invention.

It goes without saying that each of the embodiments shown below is an example, and partial replacement or combination of the configurations shown in different embodiments is possible.

The electrolytic capacitor of the present invention is impregnated with an electrolytic solution or filled with a solid electrolyte between an anode foil having a dielectric layer on its surface, a cathode foil facing the anode foil, and the anode foil and the cathode foil. An electrolytic capacitor including a laminate including at least one capacitor element having a separator, wherein the surface of the laminate in the stacking direction is the main surface, and the anode foil and the extraction surface of the cathode foil are the first side surfaces. The surface facing the first side surface is defined as the second side surface, the surface orthogonal to the first side surface and the main surface is defined as the third side surface and the fourth side surface, and the first to fourth surfaces of the separator are used. The edge located on the side surface side of the above 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 laminated electrolytic capacitor in which an anode foil having a dielectric layer on the surface and a cathode foil facing the anode foil are stacked, stress is less likely to be 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 arranged between the anode foil and the cathode foil, and the insulating resin covering the edge located on the side surface side of the laminate of the separator has a notch. Since the electrolytic solution can be injected into the separator through this notch and the amount of the electrolytic solution can be controlled accurately, the decrease in the capacitance of the electrolytic capacitor and the variation in the capacitance can be suppressed.
Further, it is also possible to manufacture an electrolytic capacitor by a manufacturing method in which a separator impregnated with an electrolytic solution in advance is laminated, and after the lamination, the electrolytic solution is further injected into the separator through a notch.

As described above, the electrolytic capacitor of the present invention is a multilayer type electrolytic capacitor, and is an electrolytic capacitor capable of injecting an electrolytic solution into a separator through a notch. Explain to.

First, the basic configuration of the electrolytic capacitor of each embodiment will be described.
The electrolytic capacitor of the present invention comprises a laminate including a capacitor element, a substrate, and a case.
In this electrolytic capacitor, the electrodes of the laminated body and the electrodes of the substrate are bonded, and the case and the substrate are bonded so as to accommodate the laminated body.
The overall structure of the electrolytic capacitor will be described with reference to FIGS. 1 to 4.

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

FIG. 1 shows a state before combining the substrate 400, the laminate 100, and the case 500. 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 laminated body 100 will be described later.

FIG. 1 shows a case 500 for accommodating 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, a metal or ceramic material can also be used. The sealing method uses a sealing material to join the substrate and the case. If a metal case is used, it can also be sealed by welding.

FIG. 2 shows a substrate 400 on which the laminated body 100 is mounted and connected to an external circuit.
The substrate 400 is a substrate having conductors formed on both sides, and an anode external electrode 410 and a cathode external electrode 420 as surface external electrodes are formed on the surface (the surface visible in the drawing) of the insulating substrate 430.
An anode external electrode and a cathode external electrode as back surface external electrodes connected to an external circuit are formed on the back surface (surface not visible in the drawing) of the insulating substrate 430 facing the front 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 conducted by a plurality of connecting 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 conducted by a plurality of connecting 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 the front surface external electrode and the back surface external electrode may be electrically connected through the electrode.

FIG. 3 shows a state in which the laminate 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.
Further, as another joining method, it is also possible to join using a conductive adhesive. Further, the bonding between the extraction portion of the anode foil and the cathode foil and the surface external electrode of the substrate may be directly performed with a conductive adhesive without forming the connection electrode.

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 electrodes are placed facing downward, and the connection electrodes of the laminated body and the surface external electrodes 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 laminated body will be described later, but 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 laminate 100 is mounted on the substrate 400 and then the case 500 is covered.
The case 500 is placed on the laminate 100 mounted on the substrate 400, and the thermoplastic resin sealing material 440 provided around the substrate 400 is sandwiched between the case 500 and the substrate 400 to heat and cool the substrate 400. As a result, the case 500 and the substrate 400 are joined to seal the laminated 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 by 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 laminate used for the electrolytic capacitor will be described.
Specific embodiments of the laminated body include several embodiments described later, but first, items common to each embodiment 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 has a first main surface M101 and a second main surface M102 facing each other in the stacking direction (T direction), a first side surface S101 which is an electrode drawing surface of the anode foil and the cathode foil, and a first side surface S101. A second side surface S102 facing the width direction (W direction), and a third side surface S103 and a third side surface facing the first side surface S101 and the first main surface M101 in the length direction (L direction). It has the side surface S104 of 4.
In addition, the "side surface" in this specification means a surface other than the main surface facing each other in the stacking direction. The laminate used in the electrolytic capacitor of the present invention has a notch in at least one of the insulating resins covering the edge of the separator laminate located on the side surface side.

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

FIG. 6 is an enlarged perspective view showing a part of the third side surface of the laminated body shown in FIG.
The third side surface S103 of the laminated body 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. Further, the third side surface S103 of the laminated body 100 has 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 how the separator can be seen from the notch of the insulating resin.

A part of the edge of the separator 30 on the anode foil 10 is covered with the insulating resin 14, and a part of the edge is exposed to the third side surface S103 from the notch 15 of the insulating resin 14. ing.
A part of the edge of the separator 40 on the cathode foil 20 is covered with the insulating resin 24, and a part of the edge is exposed to the third side surface S103 from the notch 25 of the insulating resin 24. 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 from the third side surface S103 through the notches 15 and 25 of the insulating resin.
A space is provided between the separators 30 and 40 and the third side surface S103 by the notches 15 and 25 of the 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 stacking. After injecting the electrolytic solution through the notch, the laminated body is formed by covering the portion other than the extraction portion of the connection electrode with a resin (not shown).
The shape, size, and arrangement of the notch are not particularly limited, and can be determined in consideration of the injection efficiency of the electrolytic solution and the adhesive reliability of the insulating resin.

FIG. 7A is a perspective view showing an example of the anode foil unit, and FIG. 7B is a 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 having a valve acting metal substrate 11 and dielectric layers 12 formed on both sides of the valve acting metal substrate. The solid electrolyte layer 13 is provided on the surface of the dielectric layer 12. In FIG. 7A, the valve acting metal substrate 11, the dielectric layer 12, and the solid electrolyte layer 13 are not shown as the anode foil 10.
Then, the separator 30 is arranged on the solid electrolyte layer 13 shown on the upper side of FIG. 7B. The solid electrolyte layer 13 on the anode foil 10 is not essential as the basic configuration of the electrolytic capacitor of the present invention, and may be omitted as in the embodiment described later.
It is preferable that a porous layer (not shown in FIG. 7B) is formed on both surfaces of the valve acting metal substrate 11, and the dielectric layer 12 is provided on the surface of the porous layer. Is more preferable.

As shown in FIG. 7A, an insulating resin 14 is provided around the separator 30.
The edge portions 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 the 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-toothed structure. As a result, a part of the separator 30 is exposed on the side surface of the laminated body in a periodic arrangement. One such anode foil unit may be included in the laminate, or a plurality of such anode foil units may be included in the laminate. Further, the notches may be arranged at indefinite intervals.
A part of the edge 30S4 of the separator 30 is also covered with the insulating resin 14S4 having a periodic shape.

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 side 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 side 10S1.
The cross-sectional view shown in FIG. 7B shows that 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. ..
By providing a notch 15 in a part of the insulating resins 14S1 and 14S2 covering the edge 30S1 and 30S2 of the separator, respectively, a part of the edge 30S1 or 30S2 of the separator is exposed on the side surface of the laminate. May be good.
Further, by providing a notch in a part of the insulating resin covering the edge of the separator, the edge of the separator may be exposed on any one side surface of the laminate.

FIG. 8A is a perspective view showing an example of the cathode foil unit, and FIG. 8B is a sectional view taken along 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 sides of the cathode foil 20 centering on the cathode foil 20.
Then, the separator 40 is arranged on the solid electrolyte layer 23 shown on the upper side of FIG. 8B. The solid electrolyte layer 23 on the cathode foil 20 is not essential as the basic configuration of the electrolytic capacitor of the present invention, and may be omitted as in the embodiment 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 the insulating resin 24S3 having a periodic shape. As a periodic shape, the insulating resin 24S3 has notches 25 at regular intervals and has a comb-toothed structure. As a result, a part of the separator 40 is exposed on the side surface of the laminated body in a periodic arrangement. One such cathode foil unit may be included in the laminate, or a plurality of such cathode foil units may be included in the laminate. Further, the notches may be arranged at indefinite intervals.
A part of the edge 40S4 of the separator 40 is also covered with the insulating resin 24S4 in the same manner.

The cathode foil 20 is exposed on the left side of the first side surface side 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 surface side 20S1.
The cross-sectional view shown in FIG. 8B shows that 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. ..
By providing a notch 25 in a part of the insulating resins 24S1 and 24S2 covering the edge 40S1 and 40S2 of the separator, respectively, a part of the edge 40S1 or 40S2 of the separator is exposed on the side surface of the laminate. May be good.
Further, by providing a notch in a part of the insulating resin covering the edge of the separator, the edge of the separator may be exposed on any one side surface of the laminate.

As the separator, for example, one made of paper, non-woven fabric, porous film or the like can be used. Examples of the material constituting the separator include cellulose, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, nylon, aromatic polyamide, polyimide, polyamideimide, polyetherimide, rayon, glass and the like.
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.
When the separators are provided on the anode foil and the cathode foil as shown in FIGS. 7 (a) and 8 (a), the materials and thicknesses of the separator provided on the anode foil and the separator provided on the cathode foil are the same. May be different.

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

The dielectric layer formed on the surface of the anode foil is preferably made of an oxide film of the valve acting 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 performing anodizing treatment on the surface of the aluminum foil in an aqueous solution containing ammonium adipate or the like.

It is preferable that the surface of the cathode foil is roughened and made porous by subjecting it to an etching treatment or the like. Further, the surface of the cathode foil may be formed with a dielectric layer that is much thinner than 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. Further, 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 polyphenyl sulfone resin, polyether sulfone resin, cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, etc.), soluble polyimide siloxane, and epoxy resin. , Polyimide resin, polyamide-imide resin, and insulating resin such as derivatives or precursors thereof.

A resin is used as the sealing material, and if necessary, a filler is contained.
Examples of the resin contained in the sealing material include epoxy resin and phenol resin. Examples of the filler contained in the sealing material include silica particles, alumina particles, and metal particles.

The electrolyte to be injected into the separator is an acid or base electrolyte dissolved 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). Can be mentioned. Examples of the electrolyte acid 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 base of the electrolyte include amines such as ammonia (NH ₃ ) and triethylamine (C ₆ H ₁₅ N), and amidine 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 laminate 100 constituting the electrolytic capacitor of the present invention includes a capacitor 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. The anode foil 10 having the dielectric layer 12 on the porous surface of the valve acting metal substrate 11, the cathode foil 20 facing the anode foil 10, and the separator 30 arranged between the anode foil 10 and the cathode foil 20. The capacitor element 5 is composed of 40.
In the capacitor element in which the cathode unit 2 is stacked on the anode unit 1, the separator 30 is arranged between the anode foil 10 and the cathode foil 20, but the capacitor element in which the anode unit 1 is stacked on the cathode unit 2. Then, the separator 40 is arranged between the cathode foil 20 and the anode foil 10.

9 (b) 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. 9 (a).

FIG. 9B shows a state in which the anode connection electrode 310 and the cathode connection electrode 320 are formed on the first side surface S101 of the laminate 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 drawers drawn out on the side surface of the laminate 100, and the cathode connection electrode 320 is connected to a plurality of cathode foil drawers drawn out on the side surface of the laminate 100. There is. 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 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.
The connection electrode may be one conductive film or a plurality of conductive films.

Further, although FIG. 9B shows a laminated body in which the connecting electrodes are formed, a laminated body in which the connecting electrodes are not formed may be used. When a laminate in which no connection electrode is formed is used, the anodic foil and the lead-out portion of the cathode foil and the anode external electrode and the cathode external electrode on the surface of the substrate may be directly bonded with a conductive adhesive.

The laminate shown in FIG. 5 constituting the electrolytic capacitor of the present invention can be produced, for example, by the following method.
FIG. 10 is a perspective view schematically showing an example of an anode foil sheet, and FIG. 11 is a perspective view schematically showing an example of a cathode foil sheet.
The anode foil sheet 201 shown in FIG. 10 is provided with a large number of portions to be the anode foil unit 1 shown in FIG. 7A, and a large number of anode foil units can be obtained by cutting the anode foil sheet 201 at a predetermined position. be able to.
The cathode foil sheet 202 shown in FIG. 11 is provided with a large number of portions to be the cathode foil unit 2 shown in FIG. 8A, and a large number of cathode foil units can be obtained by cutting the cathode foil sheet 202 at a predetermined position. be able to.
In FIGS. 10 and 11, the planned cutting positions of the anode foil sheet 201 and the cathode foil sheet 202 are indicated by alternate long and short dash lines.

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 pulled out.
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 pulled out.
The first through hole H1 and the fourth through hole H4 have an elongated 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.

A laminated sheet is produced by alternately laminating such an anode foil sheet 201 and a cathode foil sheet 202.
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 lamination direction.
Laminating by filling the first through hole and the third through hole, 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, respectively. Make a block body.

The produced laminated block body is heat-treated. The heat treatment cures the insulating resin and the sealing material, and integrates the anode foil and the cathode foil.

The heat-treated laminated block body is cut at the planned cutting positions of the anode foil sheet 201 and the cathode foil sheet 202 shown in FIGS. 10 and 11.

The filled sealing material 54 is cut in substantially half so as to be exposed on the first side surface S101 of the laminated body 100. As a result, the laminated body 100 as shown in FIG. 5 is obtained.
On the first side surface S101 of the laminated body 100, the anode foil 10 is exposed on the right side, and the cathode foil 20 is exposed on the left side. Then, in the first side surface S101, the right side is the drawing portion of the anode foil, and the left side is the drawing portion of the cathode foil.

Next, the electrolytic solution is injected into the separators 30 and 40 through the notches 15 and 25. The injection of the electrolytic solution can be performed while adjusting the injection amount. For example, the required amount of the electrolytic solution is specified, the total weight of the laminate is obtained, and the electrolytic solution is injected while measuring the weight of the laminate so as to be the total weight.
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 electrolytic solution evaporates due to the heat of the heat treatment, and the amount of the electrolytic solution in the separator decreases or varies. There is nothing to do.
Next, the resin is applied to the portions other than the drawer 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.
This makes it possible to protect the inside of the laminated body and prevent evaporation of the electrolytic solution when forming connection electrodes in the extraction portion of the anode foil and the extraction portion of the cathode foil in the next step.
Next, a connection electrode is formed in the extraction portion of the anode foil on the right side of the first side surface S101 and the extraction portion of the cathode foil on the left side of the first side surface S101.

The connection electrode is obtained by plating the exposed portion of the anode foil and the cathode foil exposed on the side surface of the laminate with a conductive film. For example, it can be performed by the following procedure.
First, the oil content on the surface of the laminate is removed with an alkaline treatment agent. Next, the oxide film on the exposed portion of the anode foil and the cathode foil is removed by alkaline etching. Next, the smut of the exposed portion of the anode foil and the cathode foil is removed by the smut removal treatment. Next, Zn is substituted and precipitated by zincate treatment to form a Zn metal film as a first conductive film on the exposed portion of the anode foil and the cathode foil. Next, a Ni metal film is formed on the first conductive film as the second conductive film by the Ni plating treatment. Further, a Sn metal film is formed on the second conductive film as a third conductive film by the Sn plating treatment.
The features of each specific embodiment of the laminated body will be described below.

(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 transferred between the anode foil and the cathode foil via the solid electrolyte layer on the anode side-the electrolyte in the separator-the solid electrolyte layer on the cathode side. On the other hand, when the electrolytic solution impregnated in the separator is exhausted, electrons are not exchanged in the thickness direction of the separator, so that the failure mode becomes the open mode. Therefore, it is possible to obtain a highly safe electrolytic capacitor.

Further, as a modification of the laminate used for the electrolytic capacitor according to the first embodiment of the present invention, a solid electrolyte layer is provided between the anode foil and the separator and between the cathode foil and the separator. On the other hand, a form having no solid electrolyte layer can be mentioned.
In this case as well, the failure mode when the electrolyte impregnated in the separator is exhausted is the open mode, so that the electrolytic capacitor has high safety.
Since the electrolytic capacitor of the present embodiment is a laminated type, the dielectric layer is less likely to be cracked, and the electrolytic solution can be injected into the separator through the notch, so that the amount of the electrolytic solution in the separator may decrease or vary. It is possible to suppress the decrease and variation of the capacitance without doing so.

(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 transferred between the anode foil and the cathode foil only through the electrolytic solution in the separator. On the other hand, when the electrolytic solution impregnated in the separator is exhausted, electrons are not exchanged in the thickness direction of the separator, so that the failure mode becomes the open mode. Therefore, it is possible to obtain a highly safe electrolytic capacitor.
Since the electrolytic capacitor of the present embodiment is a laminated type, the dielectric layer is less likely to be cracked, and the electrolytic solution can be injected into the separator through the notch, so that the amount of the electrolytic solution in the separator may decrease or vary. It is possible to suppress the decrease and variation of the capacitance without doing so.

(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. Further, although the separator is filled with a solid electrolyte containing a conductive polymer, the electrolyte solution is not impregnated.
To fill the separator with a solid electrolyte, the separator is immersed in a dispersion in which particles of the conductive polymer and a solvent are mixed, and then the separator is dried to evaporate the solvent, and the solid electrolyte containing the conductive polymer in the separator is used. It can be done by filling. The solid electrolyte is filled in the separator before the separator is placed on the anode foil or the cathode foil.
In the electrolytic capacitor of the third embodiment, electrons are usually transferred 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 laminated type, the dielectric layer is less likely to be cracked.

(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. Further, the separator is filled with a solid electrolyte containing a conductive polymer and is impregnated with an electrolytic solution. Filling the separator with the solid electrolyte is carried out in the same manner 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 transferred between the anode foil and the cathode foil via the solid electrolyte filled in the separator and the electrolytic solution in the separator.
Since the electrolytic capacitor of the present embodiment is a laminated type, the dielectric layer is less likely to be cracked, and the electrolytic solution can be injected into the separator through the notch, so that the amount of the electrolytic solution in the separator may decrease or vary. It is possible to suppress the decrease and variation of the capacitance without doing so.

(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. Further, the separator is filled with a solid electrolyte containing a conductive polymer and is impregnated with an electrolytic solution. Filling the separator with the solid electrolyte is carried out in the same manner 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 laminated type, the dielectric layer is less likely to be cracked, and the electrolytic solution can be injected into the separator through the notch, so that the amount of the electrolytic solution in the separator may decrease or vary. It is possible to suppress the decrease and variation of the capacitance without doing so.

(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. Further, although the separator is filled with a solid electrolyte containing a conductive polymer, the electrolyte solution is not impregnated. Filling the separator with the solid electrolyte is carried out in the same manner as in the third embodiment.
In the electrolytic capacitor of the sixth embodiment, electrons are usually transferred 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 laminated type, the dielectric layer is less likely to be cracked.

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, since the back surface external electrode is exposed as a flat electrode on the outer peripheral surface of the electrolytic capacitor, the back surface external electrode can be used to mount the electrolytic capacitor by surface mounting.

[1] An anode foil having a dielectric layer on its surface,
The cathode foil facing the anode foil and
An electrolytic capacitor comprising a laminate comprising 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 as a front surface external electrode and a front surface anode 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,
It has a case for accommodating the laminate and
The anode foil and the cathode foil are drawn out to the first side surface of the laminate.
The anode foil is connected to the anode external electrode on the surface of the substrate, and the cathode foil is connected to the cathode external electrode on the surface of the substrate.
The case is an electrolytic capacitor that accommodates the laminate and is bonded to the substrate.

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

[3] The electrolytic capacitor according to the above [2], wherein the anode connection electrode and the cathode connection electrode have a plating film.

[4] The electrolytic capacitor according to the above [3], wherein the plating film is composed of a plurality of films.

[5] The electrolytic capacitor according to the above [3] or [4], wherein the plating film contains a Zn plating film made of Zn.

[6] The electrolytic capacitor according to the above [5], wherein the plating film contains a Ni plating film made of Ni.

[7] The electrolytic capacitor according to the above [5] or [6], 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 characterized by soldering. The electrolytic capacitor according to any one of the above [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 via a conductive adhesive. The electrolytic capacitor according to any one of the above [1] to [7].

[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 via a conductive adhesive. The electrolytic capacitor according to the above [1].

[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 front surface of the substrate and the cathode external electrode on the back surface of the substrate are made by a plurality of connecting conductors. The electrolytic capacitor according to any one of the above [1] to [10], which is characterized by being taken.

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

1 Electrode foil unit 2 Electrode foil unit 5 Condenser element 10 Electrode foil 11 Valve acting metal substrate 12 Electrode layer 13, 23 Solid electrolyte layer 14, 24 Insulation resin 15, 25 Notch 20 Electrode foil 30, 40 Separator 54 Encapsulant 100 Laminated body 201 Anode foil sheet 202 Cone foil sheet 310 Ano connection electrode 320 Cone connection electrode 400 Substrate 410 Anostate external electrode 411, 421 Connection conductor 420 Cone external electrode 430 Insulation substrate 440 Sealing material 500 Case

Claims (11)

Anode foil with a dielectric layer on the surface and
The cathode foil facing the anode foil and
An electrolytic capacitor comprising a laminate comprising 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 of the laminate in the stacking direction is the main surface, and the anode foil and the extraction surface of the cathode foil are the first surfaces.
The surface facing the first side surface is referred to as the second side surface.
The first side surface and the surface orthogonal to the main surface are defined as the third side surface and the fourth side surface.
The edges of the separator located on the first to fourth side surface sides are 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 any one of claims 1 to 6, which has a solid electrolyte layer between the dielectric layer and the separator of the anode foil. The electrolytic capacitor according to any one of claims 1 to 7, which has a solid electrolyte layer between the cathode foil and the separator. A solid electrolyte layer is provided between the dielectric layer and the separator of the anode foil and between the cathode foil and the separator, and the separator is impregnated with an electrolytic solution to contain the solid electrolyte. The electrolytic capacitor according to claim 1, which is not filled. The electrolytic capacitor according to any one of claims 1 to 9, wherein the notch of the insulating resin is arranged periodically. Further, a substrate on which the laminate is mounted and electrically connected to the anode foil and the cathode foil drawn out to the first side surface of the laminate, and the substrate in a form accommodating the laminate. The electrolytic capacitor according to any one of claims 1 to 10, which has a bonded case.

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