JP2018019048A - Electrolytic capacitor and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the degradation of a resin layer in an electrolytic capacitor in which the resin layer covering a principal face of a seal member is used.SOLUTION: An electrolytic capacitor comprises: a capacitor element; a bottomed case for encasing the capacitor element; a seal member for sealing off an opening of the bottomed case; tab terminals connected to the capacitor element and extending through the seal member; and a resin layer for covering at least a part of a principal face of the seal member, which is disposed outside the bottomed case. The seal member has first holes through which the tab terminals extend. The tab terminals are in contact with the seal member at the first holes and spaced apart from the resin layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrolytic capacitor using a resin layer covering at least a part of a sealing member, and a method for manufacturing the same.

  The electrolytic capacitor includes a capacitor element, a bottomed case that accommodates the capacitor element, and a sealing member that seals the opening of the bottomed case, and a tab terminal for taking out electricity is connected to the capacitor element. Yes. The sealing member may be deteriorated by oxidation in a high temperature environment. When the sealing member is deteriorated, the sealing performance of the electrolytic capacitor is lowered. Therefore, a technique for protecting the upper surface of the sealing member with a resin layer has been proposed (for example, Patent Document 1). Moreover, using the sealing member which bonded the sealing member and the resin layer from the viewpoint of preventing a liquid leak is proposed (patent document 2). In order to reduce the thickness of the sealing member, it has also been proposed to use a sealing member in which a resin plate is embedded in the upper surface of the sealing member (Patent Document 3).

Japanese Patent Laid-Open No. 9-7901 Japanese Utility Model Publication No. 2-129723 Japanese Utility Model Publication No. 62-44522

  The tab terminal includes at least a rod-like portion penetrating a hole formed in the sealing member and a linear portion (lead wire) extending from the tip of the rod-like portion. The sealing member is in close contact with the tab terminal at the hole portion to ensure the airtightness of the electrolytic capacitor. When the entire main surface of the sealing member is covered with the resin layer, the oxidation deterioration of the sealing member can be effectively suppressed, but the resin layer easily comes into contact with the tab terminal. When the resin layer is in contact with the tab terminal, if heat is applied to the tab terminal in a high-temperature environment or due to reflow treatment, stress is applied to the resin layer due to the difference in expansion coefficient between the tab terminal and the resin layer. May deteriorate.

One aspect of the present invention is a capacitor element, a bottomed case that accommodates the capacitor element, a sealing member that seals an opening of the bottomed case, and a capacitor member that is connected to and penetrates the sealing member. A tab terminal, and a resin layer covering at least a part of a main surface arranged on the outside of the bottomed case of the sealing member,
The sealing member has a first hole through which the tab terminal passes,
The tab terminal relates to an electrolytic capacitor that is separated from the resin layer.

Another aspect of the present invention includes a capacitor element, a bottomed case that accommodates the capacitor element, a sealing member that seals an opening of the bottomed case, and is connected to the capacitor element and penetrates the sealing member. A tab terminal, and a resin layer covering at least a part of a main surface arranged outside the bottomed case of the sealing member,
The sealing member includes a rib erected in an annular shape along the opening end of the bottomed case at or near the periphery of the main surface,
The bottomed case relates to an electrolytic capacitor that is separated from the resin layer.

Still another aspect of the present invention is a step of sealing an opening of a bottomed case containing a capacitor element connected to a tab terminal with a sealing member in a state of penetrating the tab terminal extending from the capacitor element; ,
After the step of sealing, by applying a curable resin composition to the main surface arranged outside the bottomed case of the sealing member to form a coating film, and curing the coating film, Forming a resin layer covering at least a part of the main surface,
The sealing member has a first hole through which the tab terminal passes,
The present invention relates to a method for manufacturing an electrolytic capacitor, wherein in the step of forming the resin layer, the tab terminal and the resin layer are separated from each other.

  In an electrolytic capacitor using a resin layer that covers at least a part of the main surface of the sealing member, deterioration of the resin layer can be suppressed.

It is a cross-sectional schematic diagram of the electrolytic capacitor which concerns on one Embodiment of this invention. It is the schematic for demonstrating the structure of the capacitor | condenser element in the electrolytic capacitor of FIG. It is a schematic perspective view for demonstrating the structure of the sealing member in the electrolytic capacitor of FIG. It is a schematic perspective view for demonstrating the structure of the sealing member used for the electrolytic capacitor which concerns on other embodiment of this invention. It is a cross-sectional schematic diagram of the electrolytic capacitor which concerns on further another embodiment of this invention. FIG. 6 is a schematic perspective view with a part cut away for explaining the structure of a sealing member and a resin layer in the electrolytic capacitor of FIG. 5.

  An electrolytic capacitor according to an embodiment of the present invention includes a capacitor element, a bottomed case that accommodates the capacitor element, a sealing member that seals an opening of the bottomed case, and is connected to the capacitor element and penetrates the sealing member. And a resin layer covering at least a part of the main surface disposed on the outer side of the bottomed case of the sealing member. The sealing member has a hole (first hole) through which the tab terminal passes, and the tab terminal is separated from the resin layer. Alternatively, the sealing member includes a rib provided in an annular shape along the opening end of the bottomed case at or near the periphery of the main surface, and the bottomed case is separated from the resin layer.

  The electrolytic capacitor is, for example, a step of sealing the opening of the bottomed case that houses the capacitor element connected to the tab terminal with a sealing member in a state where the tab terminal extending from the capacitor element is penetrated, and a step of sealing After that, at least a part of the main surface is covered by applying a curable resin composition to the main surface arranged outside the bottomed case of the sealing member to form a coating film and curing the coating film. And a step of forming a resin layer. Here, the sealing member has a first hole through which the tab terminal passes. In the step of forming the resin layer, the resin layer is formed so that the tab terminal (and / or the bottomed case) and the resin layer are separated from each other.

  In the embodiment of the present invention, the resin layer and the tab terminal (and / or the bottomed case) are separated from each other. As a result, contact between the tab terminal (and / or the bottomed case) and the resin layer is suppressed, so even if the tab terminal and / or the bottomed case expands during reflow processing or in a high temperature environment, The resin layer is not directly affected. Therefore, deterioration (for example, breakage, such as a crack) of a resin layer can be suppressed. Further, when the tab terminal or the bottomed case becomes hot during the reflow process or in a high temperature environment, the sealing member may also expand. However, in this embodiment, since the resin layer is not fixed to the tab terminal or the bottomed case, even if the sealing member expands, deterioration of the resin layer is suppressed. By suppressing the deterioration of the resin layer, the oxidative deterioration of the sealing member is suppressed, so that it is easy to ensure insulation and increase in leakage current can be suppressed. Moreover, in the electrolytic capacitor using electrolyte solution, since evaporation of electrolyte solution can be suppressed, it can suppress that product lifetime becomes short.

  On the other hand, in the conventional technique, if the resin layer is formed in advance on the main surface on the outer side of the sealing member and then sealed, stress may be applied to the resin layer during sealing to cause deterioration. Therefore, a resin layer is formed after sealing a bottomed case with a sealing member. In this case, when the material for forming the resin layer is applied onto the sealing member, the tab terminal penetrating the sealing member is contacted, and the finally formed resin layer is also in contact with the tab terminal. When the electrolytic capacitor is reflowed, the tab terminal is heated and expands. Since the tab terminals and the resin layer have different expansion rates, if they are in contact with each other, the resin layer may deteriorate due to the expansion stress, and cracks may occur. In addition, the tab terminal is usually formed of a plurality of parts each made of metal having different linear expansion coefficients (for example, a bar-like part penetrating the sealing member, a linear part extending from the tip of the bar-like part (that is, a lead wire), etc. )including. Therefore, when heat is applied to the tab terminal in a high temperature environment or reflow treatment with the resin layer in contact with each part, a difference occurs in the expansion coefficient of each part, and this stress is easily applied to the resin layer and deteriorates. Become. Furthermore, the sealing member also expands due to the heat and expansion of the tab terminal. Therefore, when the tab terminal and the resin layer are in contact with each other, the resin layer is also deteriorated by the stress accompanying the expansion of the sealing member. The same problem occurs when the bottomed case and the resin layer come into contact with each other.

  The resin layer includes a cured product of the curable resin composition. Moreover, it is preferable that the viscosity in 23 degreeC of curable resin composition is 1-70 Pa.s. The curable resin composition having the above-described viscosity has appropriate fluidity, and a resin layer can be easily formed on the main surface of the sealing member.

The bottomed case (more specifically, the open end of the bottomed case (including the open end and the vicinity of the open end)) is preferably separated from the resin layer. In this case, contact between the bottomed case and the resin layer is suppressed, and deterioration of the resin layer is suppressed even when heat is applied to the bottomed case in a high temperature environment.
Hereinafter, embodiments of the present invention will be described more specifically with appropriate reference to the drawings. However, the following embodiments do not limit the present invention.

[First Embodiment]
(Electrolytic capacitor)
In the electrolytic capacitor according to the first embodiment of the present invention, the sealing member includes a rib. More specifically, the sealing member includes a first rib that stands up around the first hole of the main surface, and the resin layer surrounds the first rib (a region outside the first rib). It is arranged in. The tab terminal is separated from the resin layer by the first rib. In the step of forming the resin layer, a curable resin composition is applied to a region surrounding the first rib to form a coating film, the coating film is cured to form a resin layer, and the tab terminal and the resin are formed by the first rib. Separate the layers. Since the contact between the tab terminal and the resin layer is suppressed by the first rib, it is possible to suppress deterioration of the resin layer due to a high temperature environment or reflow treatment.

In the electrolytic capacitor according to the first embodiment, the sealing member may include a second rib erected in a ring shape along the opening end of the bottomed case at or near the periphery of the main surface. Moreover, you may provide both the 2nd rib and said 1st rib. In this case, the resin layer is arranged in a region (concave region) formed between the first rib and the second rib. In the step of forming the resin layer, the curable resin composition is applied to the region formed between the first rib and the second rib to form a coating film, and the coating film is cured to form the resin layer. .
When the second rib is provided in this way, the resin layer is formed inside the second rib, so that the contact between the opening end of the bottomed case and the resin layer is suppressed, and the bottomed case is used in a high temperature environment. Even if heat is applied, deterioration of the resin layer is suppressed.

  The open end of the bottomed case may be in contact with the sealing member on the second rib of the sealing member or on the outer side of the second rib. In this case, since the resin layer is formed inside the second rib, the contact between the bottomed case and the resin layer is suppressed, and even if heat is applied to the bottomed case in a high temperature environment or by reflow treatment, the resin layer Deterioration of is suppressed. On the other hand, it is preferable that the second rib of the sealing member is provided up to the end of the sealing member from the viewpoint of enhancing the stability when the opening end portion of the bottomed case is curled and pressed against the sealing member.

  The thickness of the resin layer is preferably 50 μm or more and smaller than the height of the first rib. When the sealing member has the second rib, the thickness of the resin layer is preferably smaller than the height of the second rib. In these cases, the high effect of suppressing the oxidative deterioration of the sealing member can be ensured, and the contact between the tab terminal or the bottomed case and the resin layer can be more reliably suppressed. Can be suppressed.

  FIG. 1 is a schematic cross-sectional view of an electrolytic capacitor according to this embodiment. FIG. 2 is a schematic view in which a part of the wound body related to the electrolytic capacitor is developed. FIG. 3 is a perspective view schematically showing a sealing member of the electrolytic capacitor of FIG.

  The electrolytic capacitor includes, for example, a capacitor element 10, a bottomed case 11 that houses the capacitor element 10, a sealing member 12 that closes the opening of the bottomed case 11, a seat plate 13 that covers the sealing member 12, and a sealing member 12. It includes tab terminals 14A and 14B that penetrate therethrough, and an electrolyte (for example, a liquid component such as an electrolytic solution) (not shown). The capacitor element 10 is accommodated in the outer case together with the liquid component. The opening end of the bottomed case 11 is laterally drawn inward to compress the sealing member 12, and the opening end is curled to press the main surface of the sealing member 12.

  The tab terminals 14A and 14B include first portions (linear portions) 15A and 15B, and second portions 16A and 16B connected to the first portions 15A and 15B, respectively. The second portions 16A and 16B have rod-like portions 17A and 17B penetrating the sealing member 12, and flat portions 18A and 18B integrated with the rod-like portions 17A and 17B, respectively. The end portions of the rod-like portions 17A and 17B are exposed to the outside from the sealing member 12. The linear portions (lead wires) 15A and 15B extend from the tip portions of the rod-shaped portions 17A and 17B, pass through holes formed in the seat plate 13, and are led out to the outside of the seat plate 13. The second portions 16A and 16B are connected to the capacitor element 10 via flat portions 18A and 18B, respectively.

  The capacitor element 10 includes, for example, a wound body as shown in FIG. 2, and may be manufactured by attaching a conductive polymer to the wound body. The wound body includes an anode foil 21 having a dielectric layer, a cathode foil 22, and a separator 23 interposed therebetween. The conductive polymer is adhered between the anode foil 21 and the cathode foil 22 so as to cover at least a part of the surface of the dielectric layer of the anode foil 21. In the capacitor element 10, the tab terminal 14 </ b> A is connected to the anode foil 21, and the tab terminal 14 </ b> B is connected to the cathode foil 22.

  The anode foil 21 and the cathode foil 22 are wound through a separator 23. The outermost periphery of the wound body is fixed by a winding tape 24. In addition, FIG. 2 has shown the state by which one part was expand | deployed, without stopping the outermost periphery of a wound body.

  As shown in FIG. 3, the sealing member 12 includes first holes 12a and 12b that pass through the tab terminals 14A and 14B, and first ribs 12c and 12d that are erected around the first holes 12a and 12b, respectively. In the vicinity of the periphery of the main surface (upper surface) on the outer side of the sealing member 12, a second rib 12 e is provided that is erected in an annular shape along the opening end of the bottomed case 11. The first ribs 12c and 12d are surrounded by the annular second rib 12e.

  A concave region is formed between the first ribs 12c and 12d and the second rib 12e, and the resin layer 19 is disposed in this region. Therefore, even if the resin layer 19 is formed after sealing, the contact between the resin layer 19 and the tab terminals 14A and 14B can be suppressed. In the illustrated example, since the opening end of the bottomed case 11 is positioned outside the second rib 12e, the contact between the resin layer 19 and the bottomed case 11 can also be suppressed. Therefore, even if the tab terminals 14A, 14B and the bottomed case 11 expand due to heat in a high temperature environment or during reflow processing, the influence on the resin layer 19 due to expansion can be reduced, and the stress applied to the resin layer 19 can be reduced. Can be suppressed. Therefore, deterioration of the resin layer 19 can be suppressed.

  FIG. 4 is a schematic perspective view for explaining the structure of a sealing member according to another embodiment. In the sealing member 112 of FIG. 4, the shape and position of the second rib 112e are different from the sealing member 12 of FIG. As in the example of FIG. 3, the sealing member 112 has first holes 112a and 112b that pass through the tab terminals connected to the anode foil and the cathode foil, respectively, and around the first holes 112a and 112b. The first ribs 112c and 112d are erected.

The second rib 112e is erected in an annular shape on the periphery of the sealing member 112, and the first ribs 112c and 112d are surrounded by the second rib 112e. The resin layer is formed in a concave region between the first ribs 112c and 112d and the second rib 112e. Further, the first ribs 112c and 112d and the second rib 112e may be connected.
Thus, when the sealing member has the second rib on the periphery thereof, the opening end portion of the bottomed case is sealed from the second rib (the upper surface of the second rib) so as not to contact the resin layer. Is preferably pressed. In this case, the upper surface of the second rib may be flattened or the width of the upper rib may be widened so that the opening end portion can be easily pressed stably.

Below, the structure of the electrolytic capacitor which concerns on 1st Embodiment is demonstrated in detail.
(Tab terminal)
The tab terminal penetrating the sealing member has a first portion led out from the first hole of the sealing member and a second portion connected to the capacitor element. The 1st part and 2nd part of a tab terminal are connected by welding etc., and this connection part is exposed outside from the sealing member. When the resin layer is formed on the main surface of the sealing member after sealing, the resin layer tends to be in contact with the portion exposed to the outside of the tab terminal. The tab terminal is generally formed of metal as a whole, and thus expands when exposed to a reflow process or a high temperature environment. In this embodiment, since the contact between the resin layer and the tab terminal is suppressed, deterioration of the resin layer can be suppressed even when exposed to a reflow process or a high temperature environment.

  In general, the first portion of the tab terminal often includes a first metal, and the second portion often includes a second metal different from the first metal. Since the connection portion between the first portion and the second portion is exposed to the outside from the sealing member, when the resin layer after sealing is formed, the first portion and the second portion, such as the connection portion and its periphery, The resin layer is likely to be in contact with both of them. Since the first portion and the second portion have different expansion rates when heat is applied to the tab terminal, the resin layer is likely to deteriorate when the resin layer is in contact with both portions. In the present embodiment, since the resin layer and the tab terminal are separated from each other, deterioration due to the resin layer coming into contact with the connection portion can also be suppressed.

  The second portion of the tab terminal has, for example, a rod-shaped portion that penetrates the sealing member, and the tip of the rod-shaped portion is exposed to the outside from the sealing member. The second portion may further have a flat portion connected to the capacitor element. The flat portion facilitates connection with the capacitor element. The shape of the rod-shaped portion is not particularly limited, and may be a round rod shape (for example, a rod shape having a circular or elliptical cross section) or a square bar shape (for example, a rod shape having a polygonal cross section).

  When the second portion has a flat portion, the flat portion and the rod-shaped portion may be electrically connected and may be integrated. For example, a flat portion is formed by rolling one end portion of a rod-shaped body containing the second metal, and a non-rolled region remains as a rod-shaped portion, thereby forming a second portion in which the flat portion and the rod-shaped portion are integrated. be able to.

  The first portion has, for example, a linear portion extending from the tip of the rod-shaped portion exposed from the sealing member. The linear portion is connected to one end of the rod-like portion by welding or the like. The shape of the linear portion is not particularly limited, and may be, for example, a wire shape or a ribbon shape.

  Examples of the first metal include iron, copper, nickel, and tin. The 1st metal may contain 1 type of these metals, and may contain 2 or more types. The first metal may be a single metal or an alloy containing the above metal. An example of the second metal is aluminum. Specific examples of the second metal include metallic aluminum and aluminum alloys.

The first portion includes a member containing at least one metal selected from the above group (for example, iron and / or copper) and another metal selected from the above group (for example, tin). You may have a plating film.
The size of the tab terminal (such as a rod-like portion or a flat portion) may be appropriately determined according to the size of the electrolytic capacitor, the thickness of the sealing member, and the like.

(Sealing member)
After accommodating the capacitor element, the opening of the bottomed case is sealed with a sealing member.
The sealing member may be an insulating material. As the insulating substance, an elastic body is preferable. By using a sealing member including an elastic body such as rubber, high sealing performance can be ensured. From the viewpoint of easily obtaining high heat resistance, silicone rubber, fluorine rubber, ethylene propylene rubber, chlorosulfonated polyethylene rubber (hypalon rubber, etc.), butyl rubber, isoprene rubber and the like are preferable.

  The sealing member has a shape (for example, a disk shape such as a disk shape) corresponding to the shape of the opening of the bottomed case. The bottomed case is sealed by curling the open end of the bottomed case and pressing the open end against the sealing member.

  The sealing member is formed with a first hole that penetrates the tab terminal. Since the sealing member and the tab terminal are in contact with each other in the first hole, the shape and size of the first hole are determined according to the shape and size of the tab terminal (particularly, the rod-shaped portion). As shown in FIG. 1, the sealing member usually has a pair of holes for passing an anode tab terminal connected to the anode foil of the capacitor element and a hole for passing the cathode tab terminal connected to the cathode foil. A first hole is provided. The position of the first hole is not particularly limited as long as the tab terminal connected to the anode foil and the tab terminal connected to the cathode foil can be insulated.

  The height and shape of the first rib can be appropriately determined so that the tab terminal and the resin layer do not contact each other. The height of the first rib is preferably higher than the position of the connection portion between the first portion and the second portion of the tab terminal. When the seat plate is provided as shown in FIG. 1, the height of the first rib may be the same as or lower than the position of the upper end of the bottomed case in order to mount the seat plate stably. preferable.

  The height and shape of the second rib are appropriately determined so that the resin layer is not in contact with the open end of the bottomed case while forming a resin layer having an appropriate thickness. For the same reason as in the case of the first rib, the height of the second rib is preferably the same as or lower than the position of the upper end of the bottomed case.

The heights of the first rib and the second rib are each 0.05 to 2 mm, for example, and preferably 0.1 to 0.5 mm.
The widths of the first rib and the second rib may be appropriately determined within a range in which the main surface of the sealing member can be covered with the resin layer as much as possible. The widths of the first rib and the second rib are each 0.1 to 1 mm, for example.

  The shape of the first rib and the second rib is not particularly limited, and the cross-sectional shape in the thickness direction of the sealing member may be a square shape or a shape in which the upper corner of the square shape is rounded. Since the sealing member having the first rib and the second rib is molded by a mold, each of the first rib and the second rib is provided on the lower side of the rib (on the outside of the sealing member) so that it can be easily extracted from the mold. A taper shape in which the width on the upper side is smaller than the width on the main surface side) may be employed.

(Resin layer)
A resin layer is formed on the main surface disposed outside the bottomed case of the sealing member so as to cover at least a part of the main surface. More specifically, the resin layer is disposed in an outer region surrounding the first rib provided on the main surface or a concave region formed between the first rib and the second rib. The resin layer only needs to cover at least a part of this region, but it is preferable to form the resin layer so as to cover the entire region from the viewpoint of suppressing the oxidative deterioration of the sealing member. Since the first rib or the first rib and the second rib suppress the contact between the tab terminal of the resin layer and the bottomed case, the resin layer even if the tab terminal or the bottomed case expands in a high temperature environment. Can be prevented.

  As resin contained in a resin layer, the hardened | cured material of curable resin composition is preferable, for example. In addition to the curable resin, the curable resin composition may contain a filler, a curing agent, a polymerization initiator, and / or a catalyst. Examples of the curable resin include a photocurable resin and a thermosetting resin.

  As the curable resin, for example, a compound that is cured or polymerized by the action of light or heat (for example, a monomer, an oligomer, a prepolymer, or the like) is used. Examples of such a compound (or curable resin) include epoxy compounds, phenol resins, urea resins, polyimides, polyurethanes, diallyl phthalates, and unsaturated polyesters. The curable resin composition may include a plurality of curable resins.

As the filler, for example, insulating particles and / or fibers are preferable. Examples of the insulating material constituting the filler include insulating compounds (such as oxide) such as silica and alumina, glass, mineral materials (such as talc, mica, and clay). The resin layer may contain one kind of these fillers or may contain two or more kinds in combination. Content of the filler in a resin layer is 30-80 mass%, for example.
A curing agent, a polymerization initiator, a catalyst, etc. are suitably selected according to the kind of curable resin.

  The resin layer is formed by, for example, applying a curable resin composition to the main surface of the sealing member (specifically, a region between the first rib and the second rib) to form a coating film and irradiating with light. Or by heating and curing the coating film.

  The thickness of the resin layer is not particularly limited, but is preferably 0.1 mm or more and more preferably 0.2 mm or more from the viewpoint of easily suppressing the oxidative deterioration of the sealing member. Moreover, it is preferable that it is smaller than the height of a 1st rib from a viewpoint which suppresses a contact with the tab terminal of a resin layer, and it is smaller than the height of a 2nd rib from a viewpoint which suppresses a contact with a bottomed case. It is preferable. The thickness of the resin layer is, for example, 0.5 mm or less, and preferably 0.3 mm or less.

(Bottom case)
Examples of the material of the bottomed case that houses the capacitor element include metals such as aluminum, stainless steel, copper, iron, and brass, or alloys thereof. For the bottomed case, for example, the same metal as the first metal or the second metal may be used.
After accommodating the capacitor element, the opening of the bottomed case is sealed with a sealing member.

(Capacitor element)
(Anode foil)
Examples of the anode foil include a metal foil having a roughened surface. Although the kind of metal which comprises metal foil is not specifically limited, From the point that formation of a dielectric material layer is easy, it is preferable to use the alloy which contains valve action metals, such as aluminum, a tantalum, niobium, or a valve action metal.

  The roughening of the metal foil surface can be performed by a known method. By roughening, a plurality of irregularities are formed on the surface of the metal foil. The roughening is preferably performed, for example, by etching a metal foil. The etching treatment may be performed by, for example, a direct current electrolytic method or an alternating current electrolytic method.

(Dielectric layer)
The dielectric layer is formed on the surface of the anode foil. Specifically, since the dielectric layer is formed on the surface of the roughened metal foil, the dielectric layer is formed along the inner wall surface of the hole or depression (pit) on the surface of the anode foil.

  Although the formation method of a dielectric material layer is not specifically limited, It can form by performing a chemical conversion treatment of metal foil. The chemical conversion treatment may be performed, for example, by immersing the metal foil in a chemical conversion solution such as an ammonium adipate solution. In the chemical conversion treatment, a voltage may be applied in a state where the metal foil is immersed in the chemical conversion liquid as necessary.

  Usually, from the viewpoint of mass productivity, a roughening treatment and a chemical conversion treatment are performed on a metal foil formed of a large valve metal or the like. In that case, an anode foil having a dielectric layer formed thereon is prepared by cutting the treated foil into a desired size.

(Cathode foil)
For the cathode foil, for example, a metal foil is used. The type of metal is not particularly limited, but it is preferable to use a valve action metal such as aluminum, tantalum, or niobium or an alloy containing the valve action metal. The cathode foil may be subjected to surface roughening and / or chemical conversion treatment as necessary. The roughening and chemical conversion treatment can be performed, for example, by the method described for the anode foil.

(Separator)
The separator is not particularly limited, and for example, a nonwoven fabric containing fibers of cellulose, polyethylene terephthalate, vinylon, polyamide (for example, an aromatic polyamide such as aliphatic polyamide or aramid) may be used.

  The capacitor element can be manufactured by a known method. For example, a capacitor element is manufactured by superposing an anode foil and a cathode foil on which a dielectric layer is formed via a separator, and then forming a conductive polymer layer between the anode foil and the cathode foil. May be. The anode foil and cathode foil on which the dielectric layer is formed are wound via a separator to form a wound body as shown in FIG. You may produce by forming a molecular layer. When forming the wound body, the tab terminals 14A and 14B may be planted from the wound body by winding while winding the tab terminal as shown in FIG.

  Of the anode foil, the cathode foil, and the separator, the end portion of the outer surface of the one located in the outermost layer of the wound body (the cathode foil 22 in FIG. 2) is fixed with a winding tape. In addition, when the anode foil is prepared by cutting a large metal foil, in order to provide a dielectric layer on the cut surface of the anode foil, a chemical conversion treatment is further performed on the capacitor element in a state of a wound body or the like. You may go.

As the electrolyte, an electrolytic solution, a solid electrolyte, or both can be used.
The electrolytic solution may be a non-aqueous solvent or a mixture of a non-aqueous solvent and an ionic substance (solute, for example, an organic salt) dissolved in the non-aqueous solvent. The non-aqueous solvent may be an organic solvent or an ionic liquid. As the non-aqueous solvent, for example, ethylene glycol, propylene glycol, sulfolane, γ-butyrolactone, N-methylacetamide and the like can be used. Examples of organic salts include trimethylamine maleate, triethylamine borodisalicylate, ethyldimethylamine phthalate, mono 1,2,3,4-tetramethylimidazolinium phthalate, mono 1,3-dimethyl-2-phthalate Examples include ethyl imidazolinium.

  The solid electrolyte includes, for example, a manganese compound and a conductive polymer. As the conductive polymer, for example, polypyrrole, polythiophene, polyaniline, and derivatives thereof can be used. A solid electrolyte containing a conductive polymer can be formed, for example, by subjecting a raw material monomer to chemical polymerization and / or electrolytic polymerization on a dielectric layer. Alternatively, the dielectric layer can be formed by applying a solution in which the conductive polymer is dissolved or a dispersion liquid in which the conductive polymer is dispersed to the dielectric layer.

(Electrolytic capacitor manufacturing method)
The electrolytic capacitor according to the first embodiment is a step of sealing the opening of the bottomed case that accommodates the capacitor element to which the tab terminal is connected with a sealing member in a state in which the tab terminal extending from the capacitor element is passed through; After the step of sealing, the method can be manufactured by a manufacturing method including a step of forming a resin layer covering at least a part of the main surface on the main surface disposed outside the bottomed case of the sealing member. Prior to the sealing step, the capacitor element is accommodated in the bottomed case, but the wound body before forming the conductive polymer layer is accommodated in the bottomed case, and the conductive polymer is contained in the case. A capacitor element in a state of being accommodated in a case may be obtained by forming a layer. When the wound body or the capacitor element is accommodated in the bottomed case, the tab terminal connected to the wound body or the capacitor element is accommodated so as to be positioned on the opening side of the bottomed case. The electrolyte is impregnated in the capacitor element before the sealing step. Further, the assembled electrolytic capacitor may be subjected to aging treatment while applying a rated voltage.

Below, each process is demonstrated in detail.
(Sealing process)
In the sealing step, for example, a sealing member in a state where a tab terminal extending from the capacitor element is penetrated is disposed above the capacitor element accommodated in the bottomed case, and then the opening end of the bottomed case Then, the sealing member is fixed by performing lateral drawing. Then, the open end of the bottomed case is curled, and the open end is pressed against the sealing member.

When the sealing member is disposed above the capacitor element, a tab terminal (specifically, a rod-shaped portion) extending from the capacitor element is passed through the hole formed in the sealing member, and the first portion (specifically, Is a linear part).
When a seat plate as shown in FIG. 1 is disposed, it may be disposed at the curl portion.

(Resin layer forming process)
In this step, after sealing, a resin layer is formed on the main surface (upper surface) disposed outside the bottomed case of the sealing member. For example, a coating film is formed by applying a curable resin composition to an outer region surrounding the first rib of the main surface or a region formed between the first rib and the second rib. By curing, a resin layer composed of a cured product of the curable resin composition can be formed. The coating film can be formed by a known coating method. By forming the resin layer in this way, the tab terminal and the resin layer are separated by the first rib.

From the viewpoint of easy application of the curable resin composition and easy formation of a moderately thick resin layer, the viscosity of the curable resin composition at 23 ° C. is, for example, 1 to 70 Pa · s, and 2 to 30 Pa · s. It is preferable that it is s.
The viscosity of the curable resin composition is, for example, a commercially available rotary viscometer (for example, a spindle type B-type viscometer) at 23 ° C. and a predetermined rotation speed (for example, 1 to 10 rpm). Can be measured.

  The coating film can be cured by light irradiation or heating according to the type of curable resin contained in the curable resin composition.

[Second Embodiment]
(Electrolytic capacitor)
In the electrolytic capacitor according to the second embodiment of the present invention, the resin layer has a second hole penetrating the tab terminal and continuing to the first hole. The tab terminal is separated from the resin layer by an annular gap formed between the resin layer and the tab terminal in the second hole. In the step of forming the resin layer, the second hole is formed so that an annular gap is formed between the resin layer and the tab terminal, and the tab terminal and the resin layer are separated by the annular gap. Since the contact between the tab terminal and the resin layer is suppressed by the annular gap, it is possible to suppress deterioration of the resin layer under a high temperature environment or reflow treatment.

  In the step of forming the resin layer, it is preferable to apply the curable resin composition to the main surface using a dispenser or the like. In this case, an annular gap is easily formed between the resin layer and the tab terminal or the bottomed case, and can be easily separated.

  Also in the second embodiment, it is preferable that the opening end portion of the bottomed case is separated from the resin layer. In this case, the contact between the resin layer and the bottomed case is also suppressed. Therefore, even when a difference in expansion coefficient between the members occurs during the reflow process or in a high temperature environment, the stress applied to the resin layer is smaller than that in the past, and therefore the deterioration of the resin layer is further suppressed.

  The electrolytic capacitor according to the second embodiment is different from the first embodiment only in the shapes of the resin layer and the sealing member, and the other configurations are the same as those in the first embodiment. Refer to the description of the first embodiment. it can.

  FIG. 5 is a schematic cross-sectional view of the electrolytic capacitor according to the second embodiment. FIG. 6 is a perspective view schematically showing a sealing member of the electrolytic capacitor of FIG. In addition, about the wound body which concerns on the electrolytic capacitor of FIG. 5, FIG. 2 of 1st Embodiment can be referred to as the schematic which expanded the part. In FIG. 5 as well, for the configuration other than the resin layer and the sealing member, the description of FIG. 1 of the first embodiment can be referred to.

  As shown in FIG. 5 (and FIG. 2), the sealing member 212 includes first holes 212a and 212b through which the tab terminals 14A and 14B penetrate, respectively. A resin layer 219 is formed on the outer main surface (upper surface) of the sealing member 212. The resin layer 219 has second holes 220a and 220b that are continuous with the first holes 212a and 212b, respectively. The tab terminals 14A and 14B are in contact with the sealing member 212 in the first holes 212a and 212b. On the other hand, in the second holes 220a and 220b, annular gaps are formed between the tab terminals 14A and 14B and the resin layer 219, respectively. The resin layer 219 and the tab terminals 14A and 14B are separated from each other by this gap, and contact is suppressed. By suppressing the contact, even if the tab terminals 14A and 14B and the sealing member 212 expand due to heat when exposed to a reflow process or a high temperature environment, the influence on the resin layer 219 due to the expansion is reduced. The stress applied to the resin layer 219 can be suppressed. Therefore, deterioration of the resin layer 219 can be suppressed.

  In the illustrated example, an annular gap 220c is also formed between the resin layer 219 and the open end of the bottomed case 11, so that they are separated from each other. Thereby, even if the bottomed case 11 (and the sealing member 212) expands during reflow or in a high temperature environment, stress due to the difference in expansion coefficient between the bottomed case 11 and the resin layer 219 is applied to the resin layer 219. Is suppressed, and deterioration of the resin layer 219 can be suppressed.

Below, the structure of the electrolytic capacitor which concerns on 2nd Embodiment is demonstrated in detail.
In 2nd Embodiment, although the sealing member differs from 1st Embodiment by the point which does not have a 1st rib or a 2nd rib, the description in 1st Embodiment can be referred other than that.

In the second embodiment, the resin layer is formed on the main surface of the sealing member so as to form the second hole around the tab terminal. In the portion of the second hole, an annular gap is formed between the resin layer and the tab terminal, and contact between the resin layer and the tab terminal is suppressed.
The resin layer is preferably formed so as to form an annular gap between the resin layer and the bottomed case (specifically, the open end).

The width of each of the annular gap between the resin layer and the tab terminal and the annular gap between the resin layer and the bottomed case is 0.2 to 1 mm, for example, depending on the thickness of the resin layer. 0.3 to 0.5 mm is preferable. When the width of the gap is in such a range, even if the tab terminal, the bottomed case, or the sealing member expands, it is easy to suppress the influence of stress on the resin layer.
Note that the width of the annular gap refers to the minimum width of the gap formed between the resin layer and the tab terminal or the bottomed case.
As resin contained in a resin layer, the cured | curing material of a curable resin composition is preferable similarly to the case of 1st Embodiment.

(Electrolytic capacitor manufacturing method)
Regarding the method for manufacturing the electrolytic capacitor according to the second embodiment, the description about the method for manufacturing the electrolytic capacitor according to the first embodiment can be referred to except for the resin layer forming step.
In the resin layer forming step, after sealing, the curable resin composition is applied to the main surface exposed to the outside of the sealing member to form a coating film, and the coating film is cured, whereby the curable resin composition A resin layer composed of a cured product is formed. At this time, an annular gap is formed between the resin layer and the tab terminal in the second hole, and the resin layer is formed while forming the second hole so that the tab terminal and the resin layer are separated from each other. To do. The coating film can be cured by light irradiation or heating as in the first embodiment.

  The coating film can be formed by a known coating method. For example, a cover member is placed around the tab terminal or inside the open end of the bottomed case, and a resin layer material (such as a curable resin composition) is applied to the remaining area to form a coating film. And after making it harden | cure and forming a resin layer, you may form an annular clearance in this removed position by removing the member used as a cover. From the viewpoint of simple and easy control of the shape of the resin layer, it is preferable to form a coating film by applying the material of the resin layer using a dispenser. A commercially available product can be used as the dispenser. The supply amount control method and the correction method are not particularly limited.

  Although it is easy to apply the curable resin composition, the viscosity at 23 ° C. of the curable resin composition is, for example, 1 to 70 Pa · s from the viewpoint of suppressing excessive flow of the curable resin composition. It is preferably ~ 30 Pa · s. In addition, the viscosity of curable resin composition can be measured by the above-mentioned method.

  In the above embodiment, the wound type electrolytic capacitor has been described. However, the scope of the present invention is not limited to the above, and other electrolytic capacitors, for example, a chip type using a metal sintered body instead of the anode foil The present invention can also be applied to a multilayer electrolytic capacitor using a metal plate instead of the electrolytic capacitor of FIG.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, this invention is not limited to a following example.

Example 1
In this example, a wound type electrolytic capacitor (diameter 10 mm × length 10 mm) having a rated voltage of 35 V and a rated capacitance of 270 μF was produced. Below, the specific manufacturing method of an electrolytic capacitor is demonstrated.

(Manufacture of capacitor elements)
The Al foil whose surface was roughened was subjected to chemical conversion treatment using an ammonium adipate solution to form a dielectric layer. The obtained anode foil was cut into a predetermined size. A flat body of the tab terminal is connected to the Al foil as the anode foil and the cathode foil, respectively, the anode foil and the cathode foil are wound through a separator, and the outer surface is fixed by a winding tape to be wound. Was made. At this time, the rod-like portion and the linear portion of the tab terminal were wound while the tab terminal was being wound in a state of being pulled out from the wound body. The wound body was further subjected to chemical conversion treatment using an ammonium adipate solution.

  The wound body was immersed in a conductive polymer dispersion containing polyethylene dioxythiophene, polystyrene sulfonic acid, and water contained in a predetermined container for 5 minutes, and then the wound body was pulled up from the conductive polymer dispersion. . Next, the wound body impregnated with the polymer dispersion was dried in a drying furnace at 150 ° C. for 20 minutes, and the conductive polymer was adhered between the anode foil and the cathode foil of the wound body. In this way, the capacitor element was completed and accommodated in a bottomed cylindrical case having a diameter of 10 mm and a length of 10 mm.

(Impregnation with electrolyte)
An electrolytic solution was poured into the case, and the capacitor element was impregnated with the electrolytic solution in a reduced pressure atmosphere (40 kPa). As the electrolytic solution, a solution containing γ-butyrolactone, sulfolane, and ethyldimethylamine phthalate was used.

(Capacitor element sealing)
The tab terminal led out from the capacitor element was passed through the first hole of the sealing member made of butyl rubber as shown in FIGS. 1 and 3, and the linear portion was drawn to the outside of the sealing member. In this state, the sealing member was fitted into the opening of the case and subjected to lateral drawing to fix the sealing member. The capacitor element was sealed by curling the open end of the case.

(Formation of resin layer)
A thermosetting resin composition (viscosity: 27 Pa · s) containing an epoxy resin, spherical silica having an average particle size of 10 μm as a filler, and a curing agent is used to form a first rib and a second rib on the upper surface of the sealing member. The resin layer (thickness 0.3 mm) as shown in FIG. 1 was formed by applying in between and heating the coating film above the curing temperature of the thermosetting resin composition. The filler content in the entire solid content (that is, the formed resin layer) of the curable resin composition was 75% by mass.
Thereafter, an aging treatment was performed at 130 ° C. for 2 hours while applying a rated voltage. Thus, the electrolytic capacitor was completed.

(Evaluation)
(Capacitance and ESR)
About the obtained electrolytic capacitor, the electrostatic capacity and ESR value were calculated | required in the following procedure.
Using an LCR meter for 4-terminal measurement, the capacitance (initial capacitance) (μF) of the electrolytic capacitor at a frequency of 120 Hz was measured.
The ESR value (initial ESR value) (mΩ) at a frequency of 100 kHz of the electrolytic capacitor was measured using an LCR meter for 4-terminal measurement.
The capacitance and ESR value were measured for 10 electrolytic capacitors selected at random, and the average value was calculated.

(Leak current)
Ten randomly selected electrolytic capacitors were stored at 155 ° C. for 3000 hours, a voltage of 35 V was applied between the anode foil and the cathode foil of the electrolytic capacitor, and the leakage current after 120 seconds was measured. did. Then, a product having a leakage current amount exceeding 500 μA was judged as a defective product, and the number of defective products in 10 electrolytic capacitors was defined as an LC failure rate, which was used as an index of leakage current.

(Deterioration of resin layer)
Ten randomly selected electrolytic capacitors were stored at 165 ° C. for 150 hours, and the deterioration (cracking) of the resin layer was visually observed. The number of electrolytic capacitors in which cracks were found in the resin layer in 10 electrolytic capacitors was determined.

(Example 2)
The capacitor element was sealed in the same manner as in Example 1 except that a butyl rubber sealing member as shown in FIGS. 5 and 6 was used.
A thermosetting resin composition (viscosity: 27 Pa · s) containing an epoxy resin, spherical silica having an average particle size of 10 μm as a filler, and a curing agent is dispensed (SMARTTSOT MS-1D, manufactured by Musashi Engineering Co., Ltd.). Was applied onto the sealing member. At this time, the coating film was formed so that annular gaps as shown in FIGS. 5 and 6 were formed around the tab terminals and between the opening end of the bottomed case and the coating film, respectively. The coating film was heated above the curing temperature of the thermosetting resin composition to form a resin layer (thickness 0.3 mm) as shown in FIGS. The filler content in the entire solid content (that is, the formed resin layer) of the curable resin composition was 75% by mass.

Thereafter, an aging treatment was performed at 130 ° C. for 2 hours while applying a rated voltage. Thus, the electrolytic capacitor was completed.
Evaluation was performed in the same manner as in Example 1 except that the obtained electrolytic capacitor was used.

(Comparative Example 1)
An electrolytic capacitor was formed and evaluated in the same manner as in Example 2 except that the resin layer was not formed. About the comparative example 1, it replaced with deterioration of the resin layer and evaluated deterioration (cracking) of the sealing member.

(Comparative Example 2)
The thermosetting resin composition was applied onto the sealing member so as to come into contact with the periphery of the tab terminal to form a coating film. Except for this, a resin layer was formed in the same manner as in Example 1 to produce an electrolytic capacitor. Evaluation was performed in the same manner as in Example 1 except that the obtained electrolytic capacitor was used.
The evaluation results of Examples and Comparative Examples are shown in Table 1. A1 to A2 are Examples 1 to 2, and B1 to B2 are Comparative Examples 1 to 2.

  As shown in Table 1, in the example in which the resin layer was not in contact with the tab terminal, the deterioration of the resin layer was reduced and the LC defect rate was lowered as compared with the comparative example. In Comparative Example 1 having no resin layer, the sealing member was cracked in all the electrolytic capacitors. In Comparative Example 2 in which the resin layer is in contact with the tab terminal, the resin layer was cracked in all the electrolytic capacitors.

  The present invention can be used for electrolytic capacitors (hybrid electrolytic capacitors, solid electrolytic capacitors, etc.) having a sealing member.

  10: capacitor element, 11: bottomed case, 12, 112, 212: sealing member, 12a, 12b, 112a, 112b, 212a, 212b: first hole, 12c, 12d, 112c, 112d: first rib, 12e, 112e: second rib, 13: seat plate, 14A, 14B: tab terminal, 15A, 15B: first part (linear part), 16A, 16B: second part, 17A, 17B: rod-like part, 18A, 18B: Flat part, 19, 219: resin layer, 220a, 220b: second hole, 220c: annular gap, 21: anode foil, 22: cathode foil, 23: separator, 24: winding tape

Claims (12)

A capacitor element; a bottomed case that houses the capacitor element; a sealing member that seals an opening of the bottomed case; a tab terminal that is connected to the capacitor element and passes through the sealing member; and the sealing member A resin layer covering at least a part of the main surface disposed on the outside of the bottomed case,
The sealing member has a first hole through which the tab terminal passes,
The tab terminal is an electrolytic capacitor separated from the resin layer. The sealing member includes a first rib erected around the first hole of the main surface,
The resin layer is disposed in a region surrounding the first rib;
The electrolytic capacitor according to claim 1, wherein the tab terminal is separated from the resin layer by the first rib. The sealing member further includes a second rib erected in an annular shape along the opening end of the bottomed case at or near the periphery of the main surface,
The electrolytic capacitor according to claim 2, wherein the resin layer is disposed in a region formed between the first rib and the second rib.   4. The electrolytic capacitor according to claim 3, wherein a thickness of the resin layer is 50 μm or more and is smaller than a height of each of the first rib and the second rib. A capacitor element; a bottomed case that houses the capacitor element; a sealing member that seals an opening of the bottomed case; a tab terminal that is connected to the capacitor element and passes through the sealing member; and the sealing member A resin layer covering at least a part of the main surface disposed on the outside of the bottomed case,
The sealing member includes a second rib erected in an annular shape along the opening end of the bottomed case at or near the periphery of the main surface,
The bottomed case is an electrolytic capacitor separated from the resin layer. The resin layer has a second hole through which the tab terminal penetrates and continues to the first hole,
6. The tab terminal according to claim 1, wherein the tab terminal is separated from the resin layer by an annular gap formed between the resin layer and the tab terminal in the second hole. Electrolytic capacitor.   The electrolytic capacitor according to claim 1, wherein an opening end portion of the bottomed case is separated from the resin layer. Sealing the opening of the bottomed case containing the capacitor element to which the tab terminal is connected with a sealing member in a state of penetrating the tab terminal extending from the capacitor element;
After the step of sealing, by applying a curable resin composition to the main surface arranged outside the bottomed case of the sealing member to form a coating film, and curing the coating film, Forming a resin layer covering at least a part of the main surface,
The sealing member has a first hole through which the tab terminal passes,
The method for manufacturing an electrolytic capacitor, wherein in the step of forming the resin layer, the tab terminal and the resin layer are separated from each other. The sealing member further includes a first rib erected around the first hole of the main surface,
The electrolytic capacitor according to claim 8, wherein in the step of forming the resin layer, the resin layer is formed in a region surrounding the first rib, and the tab terminal and the resin layer are separated by the first rib. Production method. The resin layer has a second hole through which the tab terminal penetrates and continues to the first hole,
In the step of forming the resin layer, the second hole is formed so that an annular gap is formed between the resin layer and the tab terminal, and the tab terminal and the resin are formed by the annular gap. The method for manufacturing an electrolytic capacitor according to claim 8, wherein the layers are separated from each other.   The method for producing an electrolytic capacitor according to claim 10, wherein in the step of forming the resin layer, the curable resin composition is applied to the main surface to form the coating film. The method for producing an electrolytic capacitor according to claim 8, wherein the curable resin composition has a viscosity at 23 ° C. of 1 to 70 Pa · s.

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