JP7122514B2 - Electrolytic capacitor - Google Patents

Description

The present disclosure relates to an electrolytic capacitor including a mold resin layer covering a sealing member.

An electrolytic capacitor includes a capacitor element including a pair of electrodes, an electrolytic solution interposed between the pair of electrodes, a case containing the capacitor element and the electrolytic solution and having an opening, and a sealing member for sealing the opening of the case. and a pair of leads electrically connected to the pair of electrodes and penetrating the sealing member. Each lead has a tab portion made mainly of aluminum, for example, and a lead portion connected to one end of the tab portion. The tab portion is connected to the electrode within the case, and the lead portion is led out of the case.

The sealing member may deteriorate due to oxidation in a high-temperature environment, and when the sealing member deteriorates, the sealing performance of the electrolytic capacitor deteriorates. Also, there is a tendency that the components of the electrolytic solution permeate the sealing member, evaporate, and gradually decrease. Therefore, it has been proposed to cover the outer surface of the sealing member facing the opening side of the case with a mold resin layer in order to improve the sealing performance within the case (Patent Document 1). By providing the mold resin layer, evaporation of electrolyte components to the outside of the case is suppressed.

JP-A-60-245106

An electrolytic capacitor according to a first aspect of the present disclosure includes a capacitor element including a pair of electrodes, an electrolytic solution interposed between the pair of electrodes, a case containing the capacitor element and the electrolytic solution, a sealing member, and a sealing A pair of leads penetrating through the member and a mold resin layer are provided. The case has an opening. The sealing member seals the opening of the case. A pair of leads are electrically connected to a pair of electrodes, respectively. The mold resin layer covers at least part of the outer surface of the sealing member facing the opening side. At least one of the pair of leads has a tab portion and a lead portion. The tab portion is connected to the electrode. The drawer portion is connected to one end of the tab portion. One end of the tab protrudes from the outer surface of the sealing member.

According to the present disclosure, lead corrosion can be suppressed in an electrolytic capacitor including a mold resin layer covering at least a portion of the outer surface of the sealing member facing the opening side of the case.

Further, an electrolytic capacitor according to a second aspect of the present disclosure includes a capacitor element including a pair of electrodes, an electrolytic solution interposed between the pair of electrodes, a case containing the capacitor element and the electrolytic solution, and a sealing member. , a mold resin layer covering the sealing member, and a pair of leads passing through the sealing member and the mold resin layer. The case has an opening. The sealing member seals the opening of the case. A pair of leads are electrically connected to a pair of electrodes, respectively. At least one of the pair of leads has an insulating region covered with an electrically insulating layer. The electrical insulating layer is provided between at least one of the pair of leads and at least one of the sealing member and the mold resin layer.

According to the present disclosure, corrosion of leads of an electrolytic capacitor having a mold resin layer covering a sealing member can be suppressed.

Further, an electrolytic capacitor according to a third aspect of the present disclosure includes a capacitor element including a pair of electrodes, a case that houses the capacitor element, a sealing member, a mold resin layer that covers the sealing member, the sealing member and the mold resin and a pair of leads passing through the layers. The case has an opening. The sealing member seals the opening of the case. A pair of leads are electrically connected to a pair of electrodes, respectively. A gap is provided between the sealing member and the mold resin layer.

According to the present disclosure, it is possible to suppress deterioration in the sealing performance of the electrolytic capacitor due to cracks occurring in the mold resin layer.

1 is a schematic cross-sectional view of an electrolytic capacitor according to a first embodiment of the present disclosure; FIG. 1 is a schematic diagram for explaining the configuration of an example of a capacitor element; FIG. FIG. 4 is a schematic cross-sectional view of an electrolytic capacitor according to a first modified example of the first embodiment of the present disclosure; FIG. 5 is a schematic cross-sectional view of an electrolytic capacitor according to a second modification of the first embodiment of the present disclosure; 1 is a schematic cross-sectional view of an electrolytic capacitor according to a reference embodiment of the present disclosure; FIG. FIG. 6 is a cross-sectional view of essential parts showing the vicinity of the boundary between the sealing member and the mold resin layer in FIG. 5 ; FIG. 5 is a schematic cross-sectional view of an electrolytic capacitor according to a second embodiment of the present disclosure; FIG. 5 is a schematic cross-sectional view of an electrolytic capacitor according to a modification of the second embodiment of the present disclosure; FIG. 10 is a cross-sectional view of the essential parts of the electrolytic capacitor when the rod-shaped portion is inserted into the sealing member so that the joint portion between the lead-out portion and the rod-shaped portion is positioned in the hole of the sealing member after providing the electrical insulating layer. FIG. 10 is a cross-sectional view of the essential parts of the electrolytic capacitor when the rod-shaped portion is inserted into the sealing member so that the joint portion between the lead-out portion and the rod-shaped portion is positioned outside the hole of the sealing member after the electrical insulating layer is provided; FIG. 4 is a cross-sectional view of the essential parts of an electrolytic capacitor in which an electrical insulating layer is provided after the rod-shaped portion is inserted into the sealing member so that the joint portion between the lead-out portion and the rod-shaped portion is positioned in the hole of the sealing member; FIG. 4 is a cross-sectional view of the essential parts of an electrolytic capacitor in which an electrical insulating layer is provided after the rod-shaped portion is inserted into the sealing member so that the joint portion between the lead-out portion and the rod-shaped portion is positioned outside the hole of the sealing member; FIG. 6 is a schematic cross-sectional view of an electrolytic capacitor according to a third embodiment of the present disclosure; FIG. 10 is a cross-sectional view of the essential parts of the electrolytic capacitor when a gap is formed in a state where the rod-shaped portion is inserted into the hole of the sealing member so that the joint portion between the lead-out portion and the rod-shaped portion is positioned within the hole of the sealing member; be. FIG. 10 is a cross-sectional view of the essential parts of the electrolytic capacitor when a gap is formed in a state where the rod-shaped portion is inserted into the hole of the sealing member so that the joint portion between the lead-out portion and the rod-shaped portion is positioned outside the hole of the sealing member; be. FIG. 11 is a schematic cross-sectional view of an electrolytic capacitor according to a modification of the third embodiment of the present disclosure;

Prior to describing the embodiments of the present disclosure, problems in the prior art will be briefly described. A pair of leads pass through the sealing member and the mold resin layer and are drawn out from the mounting surface side of the mold resin layer. An electrolytic solution (for example, a solvent) relatively easily permeates a sealing member containing a rubber component, but hardly permeates a mold resin layer. Therefore, when the outer surface of the sealing member is covered with the mold resin layer, the electrolytic solution may remain inside the sealing member or at the boundary between the sealing member and the mold resin layer. In such a case, chlorine components (components containing chlorine) contained in the sealing member tend to dissolve into the electrolytic solution. Corrosion of the leads may progress when the leads come into contact with an electrolyte containing chlorine.

More specifically, the structure of an example of the electrolytic capacitor according to the reference embodiment of the present disclosure will be described with reference to FIGS.

Electrolytic capacitor 1D includes capacitor element 10, an electrolytic solution (not shown), and case 11 that accommodates capacitor element 10 and the electrolytic solution. The opening of the case 11 is sealed with a sealing member 12 . The outer surface of the sealing member 12 facing the opening of the case 11 (hereinafter also simply referred to as the outer surface of the sealing member 12 ) is covered with a mold resin layer 13 . Leads 14A and 14B are connected to a pair of electrodes of the capacitor element 10, respectively.

Leads 14A and 14B have tab portions 16A and 16B connected to one electrode and the other electrode, respectively, and lead portions 15A and 15B connected to tab portions 16A and 16B, respectively. Connection portions between the tab portions 16A and 16B and the lead portions 15A and 15B are hereinafter also referred to as lead internal connection portions 175A and 175B.

One electrode is the anode and the other electrode is the cathode. The anode has a dielectric layer on its surface. The electrolytic capacitor may comprise a solid electrolyte layer covering at least part of the surface of the dielectric layer. One lead is the anode lead connected to the anode and the other lead is the cathode lead connected to the cathode.

In the illustrated example, the tab portions 16A and 16B have rod-shaped portions 17A and 17B and flat portions 18A and 18B, respectively. Flats 18A and 18B are connected to the anode and cathode, respectively. The rod-shaped portions 17A and 17B are connected to the drawer portions 15A and 15B, respectively. At least part of the lead-out portions 15A and 15B are drawn out from the mounting surface 13S of the mold resin layer 13 and housed in groove portions 13A and 13B provided in the mounting surface 13S. Bottom surfaces 13a and 13b of grooves 13A and 13B preferably have a predetermined inclination.

One ends of the rod-shaped portions 17A and 17B (hereinafter also referred to as tip portions) are located in through-holes provided in the sealing member 12 . In the vicinity of the boundary between the sealing member 12 and the mold resin layer 13, electrolyte components tend to stay. When the tips of the rod-shaped portions 17A and 17B are positioned in the through-holes of the sealing member 12, the electrolytic solution components remaining near the boundary between the sealing member 12 and the mold resin layer 13 are released into the lead inner connection portions 175A and 175B and the lead-out portions. It becomes easier to contact the portions 15A and 15B. At this time, the internal lead connection portions 175A and 175B and the lead portions 15A and 15B are corroded by the retained electrolyte components. Also, the electrolytic solution enters a wide range of the boundary between the sealing member 12 and the mold resin layer 13, and the electrolytic solution enters between the lead internal connection portions 175A and 175B of the pair of leads 14A and 14B and/or between the lead portions 15A and 15B. If the components remain, corrosion of the lead internal connection portions 175A and 175B and/or the lead portions 15A and 15B (particularly on the anode lead side) is accelerated when a voltage is applied between the leads. Furthermore, as shown in FIG. 6, when the tip portions of the rod-shaped portions 17A and 17B are positioned inside the through holes of the sealing member, gaps are likely to occur between the leads 14A and 14B and the mold resin layer 13. FIG. Electrolyte components tend to stay in such gaps, accelerating corrosion of the internal lead connection portions 175A and 175B and/or the lead portions 15A and 15B.

(First embodiment)
An electrolytic capacitor according to a first embodiment of the present disclosure includes a capacitor element including a pair of electrodes, an electrolytic solution interposed between the pair of electrodes, a case containing the capacitor element and the electrolytic solution, a sealing member, and a sealing A pair of leads penetrating through the member and a mold resin layer are provided. The sealing member seals the opening of the case. A pair of leads are electrically connected to a pair of electrodes, respectively. The mold resin layer covers at least part of the outer surface of the sealing member. At least one of the pair of leads has a tab portion and a lead portion. The tab portion is connected to the electrode. The drawer portion is connected to the distal end portion of the tab portion. The tip of the tab protrudes from the outer surface of the sealing member. As a result, the stagnating electrolytic solution components are prevented from coming into contact with the connecting portion between the tip portion of the rod-shaped portion and the lead-out portion. Therefore, troubles such as breakage of leads are less likely to occur.

Among the leads, the tab portion (or rod-shaped portion and flat portion) is originally a portion to be housed in the case, so it is made of a material (valve metal, etc.) that is resistant to corrosion due to contact with the electrolyte. . For example, since the tab portion is covered with an oxide film, corrosion is unlikely to occur. On the other hand, the connecting portion (in-lead connecting portion) between the tab portion and the lead-out portion and the lead-out portion following this contain, for example, a material (transition metal such as Fe, Cu, etc.) that is easily corroded, such as a CP wire or a Cu wire. By protruding the end of the tab portion on the lead-out portion side (or the tip of the rod-shaped portion) from the sealing member, the lead internal connection portion and the lead-out portion following this are separated from the boundary between the mold resin layer and the sealing member. be able to. This suppresses the contact between the electrolytic solution component and the lead internal connection portion and the lead portion.

When both of the pair of leads are in contact with the stagnating electrolytic solution components and a voltage is applied, the lead components are electrolyzed and corrosion of the leads is accelerated. Therefore, corrosion of the leads can be suppressed by suppressing contact between at least one of the pair of leads and the components of the electrolyte. Among the anode lead and the cathode lead, the corrosion of the anode lead tends to progress, so it is preferable that at least the lead-side end of the anode lead (or the tip of the bar-shaped portion) protrude from the outer surface of the sealing member. However, in order to enhance the effect of suppressing corrosion of the leads, it is desirable to suppress contact between both the pair of leads and the components of the electrolytic solution.

The lead internal connection portion may be embedded in the mold resin layer. As a result, an adhesive interface is formed between the mold resin layer and the lead internal connection portion. Since the remaining electrolytic solution components do not easily enter the bonding interface, the effect of suppressing corrosion of the leads is enhanced. In addition, the lead internal connection portion usually has a welding mark between the tab portion and the lead portion. If at least a part of the weld marks is covered with the mold resin layer, a corresponding corrosion suppression effect can be obtained.

The end portion of the tab portion on the lead-out portion side may have an exposed portion that is not covered with the molding resin layer. Since the exposed portion does not form an adhesive interface between the mold resin layer and the lead, the components of the electrolytic solution do not creep up to the exposed portion due to capillary action. Since the exposed portion is always exposed to the outside air, it is less likely to get wet with the components of the electrolytic solution and is more likely to dry. Therefore, the leads are prevented from coming into contact with the electrolytic solution components.

The entire tab portion protruding from the outer surface of the sealing member may be exposed without being covered with the mold resin layer. In this case, a region having no mold resin layer is formed around the through hole through which the lead passes so as to surround the through hole. At this time, the boundary between the mold resin layer and the sealing member is not formed around the tab portion protruding from the sealing member, and that portion is exposed to the outside. Therefore, retention of electrolyte solution components around the tab portion protruding from the sealing member is further suppressed.

On the other hand, the end portion of the tab portion on the lead-out portion side may be embedded in the mold resin layer so that the entire welding mark is covered with the mold resin layer. At this time, a portion of the lead-out portion following the end of the tab portion on the lead-out portion side may also be embedded in the mold resin layer.

The tab portion is preferably covered with an oxide film of the metal forming the tab portion. As a result, corrosion due to contact between the tab portion and electrolyte components is less likely to occur. For example, if the tab portion includes a valve metal such as aluminum, the tab portion can be anodized to form an oxide coating on the tab portion. It is sufficient to form the oxide film only on the anode lead, but the oxide film may be formed on the cathode lead.

The lead-out portion is preferably a flexible linear member. The linear member preferably comprises a core material and a plated layer covering the surface of the core material. It is preferable that the core material is mainly composed of, for example, Cu, which is excellent in conductivity, steel, Fe, or the like. The plated layer is preferably made of a low melting point metal. By providing the lead portion with a plated layer of a low-melting-point metal, it becomes easy to connect the lead portion to a predetermined connected electrode. Specifically, a CP wire, a Cu wire, or the like can be used for the lead portion. A CP wire is a linear member in which a core material is made of steel, Fe, or the like, and a plating layer is made of Sn, Cu, or the like. A Cu wire is a linear member in which a core material is made of Cu and a plating layer is made of Sn or the like.

When a transition metal is contained in the lead-out portion, the transition metal is likely to be eluted into the electrolytic solution components from the lead-out portion. On the other hand, by protruding the end of the tab portion on the side of the lead-out portion from the outer surface of the sealing member, the corrosion of the lead-out portion is remarkably suppressed.

Evaporation of electrolyte components is suppressed from the outer surface of the sealing member covered with the mold resin layer. Therefore, the mold resin layer only needs to cover at least part of the outer surface of the sealing member. As already described, a region having no mold resin layer may be provided around the through-hole for passing the lead in the outer surface of the sealing member so as to surround the through-hole. However, it is preferable that the outer surface of the sealing member is covered with a mold resin layer except for the area around the through hole. At this time, it is preferable that 50% or more of the area of the outer surface of the sealing member is covered with the mold resin layer. The entire area (100%) of the outer surface of the sealing member may be covered with the mold resin layer.

It is preferable that the mold resin layer covers at least a portion of the side surface of the case that follows the opening in addition to the outer surface of the sealing member. As a result, the tightness in the case can be further improved. It is preferable that the mold resin layer is in close contact with the case in a region facing the case. Thereby, the mold resin layer can be more firmly fixed to the sealing member.

The electrolytic capacitor according to the first embodiment of the present disclosure will be specifically described below with reference to the drawings, but the present disclosure is not limited thereto.

An electrolytic capacitor 1A shown in FIG. 1 includes a capacitor element 10, an electrolytic solution (not shown), and a case 11 containing them and having an opening. The case 11 is, for example, a cylinder with a bottom. The opening of the case 11 is sealed with a sealing member 12 . The entire outer surface of the sealing member 12 facing the opening side of the case 11 is covered with a mold resin layer 13 . The mold resin layer 13 is provided so as to cover the opening of the case 11 together with the outer surface of the sealing member 12 , and further covers at least a portion of the side surface of the case 11 following the opening.

The opening of case 11 is sealed with sealing member 12 and mold resin layer 13 after accommodating capacitor element 10 . The open end of the case 11 is drawn toward the sealing member 12 and caulked inward. Thereby, the sealing member 12 is fixed to the opening of the case 11 , and the case 11 is sealed by the sealing member 12 . The mold resin layer 13 may be partially adhered to the case 11 in the region facing the case 11, and may not be adhered to some portions.

Mold resin layer 13 preferably contains a cured product of a curable resin composition. The curable resin composition may contain a filler, a curing agent, a polymerization initiator, and/or a catalyst in addition to the curable resin. Examples of curable resins include photocurable resins and thermosetting resins. Curing agents, polymerization initiators, catalysts and the like are appropriately selected according to the type of curable resin.

As curable resins, for example, compounds that cure or polymerize under the action of heat (eg, monomers, oligomers, prepolymers, etc.) are used. Examples of such compounds (or curable resins) include epoxy resins, phenolic resins, urea resins, polyimides, polyamideimides, polyurethanes, diallyl phthalate, unsaturated polyesters, and the like. The curable resin composition may contain multiple curable resins.

As the filler, for example, insulating particles (inorganic or organic) and/or fibers are preferable. Examples of the insulating material that constitutes the filler include insulating compounds (oxides, etc.) such as silica and alumina, glass, mineral materials (talc, mica, clay, etc.), and the like. The mold resin layer may contain one type of these fillers or may contain two or more types in combination. The content ratio of the filler in the mold resin layer is, for example, 10% by mass or more and 90% by mass or less.

The mold resin layer 13 may contain a thermoplastic resin or a composition containing this. Examples of thermoplastic resins that can be used include polyphenylene sulfide (PPS) and polybutylene terephthalate (PBT).

Mold resin layer 13 can be formed using molding techniques such as injection molding, insert molding, and compression molding. The mold resin layer 13 is formed by, for example, using a predetermined mold and applying a curable resin composition or a thermoplastic resin (composition) to the outer surface of the sealing member 12 and the opening of the case 11 . It can be formed by filling in places.

Capacitor element 10 shown in FIG. 2 is formed by winding anode 21 and cathode 22 with separator 23 interposed therebetween. Anode lead 14A and cathode lead 14B are electrically connected to anode 21 and cathode 22, respectively. Each lead extends through the sealing member 12 to the outside.

Anode lead 14A and cathode lead 14B have tab portions 16A and 16B connected to anode 21 and cathode 22, respectively, and lead portions 15A and 15B connected to tab portions 16A and 16B, respectively. Tab portions 16A and 16B contain, for example, aluminum. The lead portions 15A and 15B are, for example, CP wires or Cu wires containing metals such as iron, copper, nickel, and tin. When electrolytic capacitor 1A is mounted on a substrate, electrodes to be connected on the substrate and leads 14A and 14B of capacitor element 10 are electrically connected via lead portions 15A and 15B.

The tab portions 16A, 16B respectively have rod-shaped portions 17A, 17B and flat portions 18A, 18B. The rod-shaped portions 17A, 17B and the flat portions 18A, 18B may be electrically connected to each other, and may be integrated. For example, the flat portion is formed by rolling a portion of the rod. The non-rolled areas remain as bars. Thereby, the tab portions 16A and 16B in which the flat portion and the bar-shaped portion are integrated can be formed.

The rod-shaped portions 17A and 17B penetrate the sealing member 12 respectively. The shape of the rod-shaped portions 17A and 17B is not particularly limited, and may be a round rod shape (eg, a rod shape with a circular or elliptical cross section) or a square rod shape (eg, a rod shape with a polygonal cross section). Bar-shaped portions 17A and 17B are connected to capacitor element 10 via flat portions 18A and 18B, respectively. Having the flat portions 18A and 18B facilitates connection between the leads 14A and 14B and the anode and cathode.

The lead-out portions 15A and 15B are connected to the tip portions of the rod-shaped portions 17A and 17B by welding or the like, and lead inner connection portions 175A and 175B are formed at the boundaries between the lead-out portions 15A and 15B and the rod-shaped portions. At least part of the lead-out portions 15A and 15B are led out to the outside through the mold resin layer 13, respectively. The shape of the lead-out portions 15A and 15B is not particularly limited, and may be wire-like or ribbon-like, for example.

The tip portions of the rod-shaped portions 17A and 17B protrude from the outer surface of the sealing member 12. As shown in FIG. The distance D between the inner-lead connecting portions 175A, 175B corresponding to the most distal end portions of the bar-shaped portions 17A, 17B or the portion of the welding mark closest to the lead-out portion side and the outer surface of the sealing member 12 is the lead-out portion 15A, 15B or the lead innermost portion. From the viewpoint of suppressing contact between the connection portions 175A and 175B and the components of the electrolytic solution, the larger the size, the better. The distance D is preferably 5% or more of the maximum thickness T of the mold resin layer 13 . At this time, it is desirable that the tip portions of the bar-shaped portions 17A and 17B do not protrude from the mounting surface 13S of the mold resin layer 13. FIG. Here, the maximum thickness T of the mold resin layer 13 is the maximum vertical distance between the mounting surface 13S of the mold resin layer 13 and the outer surface of the sealing member 12 . The vertical distance means the distance in the normal direction of the outer surface of the sealing member 12 .

In the above configuration, the internal lead connection portions 175A and 175B are embedded in the mold resin layer 13. As shown in FIG. The ends of the rod-shaped portions 17A and 17B are entirely covered with the mold resin layer 13, and the adhesion interface between the mold resin layer 13 and the ends of the rod-shaped portions 17A and 17B is formed with a sufficiently large area. Due to such an adhesive interface, contact between the lead internal connection portions 175A and 175B or the lead portions 15A and 15B and the electrolytic solution components is remarkably suppressed.

As shown in FIG. 1, the mounting surface 13S of the mold resin layer 13 is provided with elongated grooves 13A and 13B. The lead-out portions 15A and 15B have portions led out from the mounting surface 13S. The portion is accommodated in the grooves 13A and 13B and is arranged near the mounting surface 13S.

The bottom surfaces 13a and 13b are inclined so that the depth of the grooves 13A and 13B gradually increases from the point where the lead-out portions 15A and 15B start to be pulled out from the mold resin layer 13 toward the outer periphery of the mounting surface 13S. there is When the lead-out portions 15A and 15B are bent substantially parallel to the mounting surface 13S, a restoring force acts on the lead-out portions 15A and 15B to return them to their original shapes. In consideration of this restoring force, the bottom surfaces of the grooves 13A and 13B are inclined as described above. The inclination angles of the bottom surfaces 13a and 13b with respect to the mounting surface 13S are, for example, 3° or more and 30° or less. The depths of the grooves 13A and 13B may be made constant without inclining the bottom surfaces 13a and 13b.

The sealing member 12 may be made of an insulating material. An elastic body is preferable as the insulating material. By using the sealing member 12 containing an elastic body such as rubber, high sealing performance can be ensured. Silicone rubber, fluororubber, ethylene propylene rubber, chlorosulfonated polyethylene rubber (Hypalon (trademark) rubber, etc.), butyl rubber, isoprene rubber, and the like are preferable from the viewpoint of easily obtaining high heat resistance.

The sealing member 12 has a shape corresponding to the shape of the opening of the case 11 (for example, a disc shape such as a disc shape). The sealing member 12 has through holes for passing the rod-shaped portions 17A and 17B. The shape and size of the through-hole may be appropriately determined according to the shape and size of the rod-shaped portions 17A and 17B.

The capacitor element 10 will be described below.

Capacitor element 10 has, for example, a wound body as shown in FIG. The wound body includes an anode 21 having a dielectric layer, a cathode 22, and a separator 23 interposed therebetween. In the capacitor element 10, the lead 14A is connected to the anode 21 and the lead 14B is connected to the cathode 22. As shown in FIG.

Anode 21 and cathode 22 are wound with separator 23 interposed therebetween. The outermost circumference of the wound body is fixed by a winding stop tape 24 . In addition, FIG. 2 shows a state in which a part of the wound body is unfolded without stopping the outermost circumference of the wound body.

As the anode 21, for example, a metal foil having a roughened surface is used. The type of metal that constitutes the metal foil is not particularly limited, but it is preferable to use a valve metal such as aluminum, tantalum, or niobium, or an alloy containing a valve metal, because the dielectric layer can be easily formed.

Roughening of the metal foil surface can be performed by a known method. A plurality of irregularities are formed on the surface of the metal foil by roughening. Roughening is preferably performed by etching the metal foil, for example. The etching treatment may be performed by, for example, a DC electrolysis method or an AC electrolysis method.

A dielectric layer is formed on the surface of the anode 21 . Specifically, since the dielectric layer is formed on the roughened surface of the metal foil, it is formed along the inner wall surfaces of the holes and depressions (pits) on the surface of the anode 21 .

Although the method of forming the dielectric layer is not particularly limited, it can be formed by chemically converting a 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, if necessary, voltage may be applied while the metal foil is immersed in a chemical conversion solution.

A metal foil, for example, is used for the cathode 22 . Although the type of metal is not particularly limited, it is preferable to use a valve-acting metal such as aluminum, tantalum, or niobium, or an alloy containing a valve-acting metal. Cathode 22 may be roughened and/or chemically treated, if desired. Surface roughening and chemical conversion treatment can be performed, for example, by the method described for anode 21 .

The separator 23 is not particularly limited, and for example, a nonwoven fabric containing fibers of cellulose, polyethylene terephthalate, vinylon, polyamide (for example, aromatic polyamide such as aliphatic polyamide and aramid) may be used.

A wound body can be produced by a known method. When forming the wound body, the leads 14A and 14B may be erected from the wound body as shown in FIG. 2 by winding while winding the leads.

Capacitor element 10 includes an electrolyte. The electrolyte 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 therein. The non-aqueous solvent may be an organic solvent or an ionic liquid. Examples of non-aqueous solvents that can be used include ethylene glycol, propylene glycol, sulfolane, γ-butyrolactone, and N-methylacetamide. Examples of organic salts include trimethylamine maleate, triethylamine borodisalicylate, triethylamine phthalate, ethyldimethylamine phthalate, mono-1,2,3,4-tetramethylimidazolinium phthalate, mono-1,3-phthalate, dimethyl-2-ethylimidazolinium and the like.

Capacitor element 10 may include a solid electrolyte layer covering at least a portion of the surface of the dielectric layer.

The solid electrolyte layer contains, for example, a manganese compound or a conductive polymer. Examples of conductive polymers that can be used include polypyrrole, polythiophene, polyaniline, and derivatives thereof. The solid electrolyte layer can be formed, for example, by chemically and/or electrolytically polymerizing raw material monomers on the dielectric layer. Alternatively, it can be formed by applying a solution in which a conductive polymer is dissolved or a dispersion in which a conductive polymer is dispersed to the dielectric layer.

Materials for the case 11 include, for example, metals such as aluminum, stainless steel, copper, iron, and brass, or alloys thereof.

(First Modification of First Embodiment)
The electrolytic capacitor 1B shown in FIG. 3 has the same structure as that of the first embodiment except that the tip portions of the rod-shaped portions 17A and 17B of the tab portions 16A and 16B are not embedded in the mold resin layer 13. As shown in FIG. Also in this modification, the lead internal connection portions 175A and 175B and the lead-out portions 15A and 15B following them can be sufficiently separated from the boundary between the sealing member 12 and the mold resin layer 13 . In addition, in FIG. 3, the same code|symbol is attached|subjected to the same component as the component in 1st Embodiment shown in FIG.

The mold resin layer 13 entirely covers the outer surface of the sealing member 12 . On the other hand, the tip portions of the rod-shaped portions 17A and 17B and the internal lead connection portions 175A and 175B are not embedded in the mold resin layer 13 and are exposed to the outside. Such an exposed portion does not cause capillary action that promotes the creeping up of electrolyte components. In addition, the exposed portion is always exposed to the outside air and tends to dry. As described above, it is further suppressed that the components of the electrolytic solution stay between the leads.

Also here, the distance D is preferably 5% or more of the maximum thickness T of the mold resin layer 13 . At this time, it is desirable to set the distance D so that the tips of the bar-shaped portions 17A and 17B do not protrude from the mounting surface 13S of the mold resin layer 13. FIG.

When the elongated grooves 13A and 13B are provided on the mounting surface 13S of the mold resin layer 13, the depth of the grooves 13A and 13B should be increased where the tips of the bar-shaped portions 17A and 17B protrude from the mold resin layer 13. is preferred. As a result, the internal lead connection portions 175A and 175B and the lead portions 15A and 15B following them can be accommodated in the groove portions 13A and 13B. Therefore, it is possible to prevent the extension portions 15A and 15B from protruding from the mounting surface 13S.

(Second Modification of First Embodiment)
In the electrolytic capacitor 1</b>C shown in FIG. 4 , the entire portions of the rod-shaped portions 17</b>A and 17</b>B that protrude from the outer surface of the sealing member 12 are exposed without being covered with the mold resin layer 13 . Other than this point, it has the same structure as the first embodiment. Also here, the distance D is preferably 5% or more of the maximum thickness T of the mold resin layer 13 . In addition, in FIG. 4, the same code|symbol is attached|subjected to the same component as the component in 1st Embodiment shown in FIG.

A region not covered with the mold resin layer 13 is formed around the through hole of the sealing member 12 through which the rod-shaped portions 17A and 17B protrude so as to surround the through hole. For example, the mold resin layer 13 is formed with cylindrical through-holes into which parts of the rod-shaped portions 17A and 17B are inserted. In this case, the boundary between the mold resin layer 13 and the sealing member 12 is not formed at least partially around the rod-shaped portions 17A and 17B projecting from the sealing member 12, and the outer surface of the sealing member 12 is slightly exposed. Therefore, the boundary between the sealing member 12 and the mold resin layer 13 is discontinuous around the rod-shaped portions 17A and 17B protruding from the sealing member 12 . In addition, the rod-shaped portions 17A and 17B protruding from the sealing member 12 do not cause a capillary phenomenon that promotes the creeping up of electrolyte components, and the tips of the rod-shaped portions 17A and 17B are always exposed to the outside air and dried. easier. As described above, the corrosion of the leads due to the components of the electrolytic solution is further suppressed.

If at least one of the anode lead and the cathode lead protrudes from the outer surface of the sealing member as shown in FIG. 1, FIG. 3, or FIG. 4, contact of the lead with electrolyte components is suppressed. Also, one of the anode lead and the cathode lead has any configuration shown in FIG. 1, 3 or 4, and the other has any other configuration shown in FIG. 1, 3 or 4. may have

(Second embodiment)
An electrolytic capacitor according to a second embodiment of the present disclosure includes a capacitor element including a pair of electrodes, an electrolytic solution interposed between the pair of electrodes, a case containing the capacitor element and the electrolytic solution, a sealing member, and a sealing member. and a pair of leads passing through the sealing member and the mold resin layer. The case has an opening. The sealing member seals the opening of the case. A pair of leads are electrically connected to a pair of electrodes, respectively. At least one of the pair of leads has an insulating region covered with an electrically insulating layer. The electrical insulating layer is provided between at least one of the pair of leads and at least one of the sealing member and the mold resin layer. The electrical insulating layer may be formed in at least part of the region where the lead penetrates the sealing member and the mold resin layer.

One of the pair of electrodes is the anode and the other is the cathode. The anode has a dielectric layer on its surface. One of the pair of leads is an anode lead electrically connected to the anode and the other is a cathode lead electrically connected to the cathode.

By providing the insulating region (electrically insulating layer), even if the electrolyte stays inside the sealing member or at the boundary between the sealing member and the mold resin layer, the leads can be kept in contact with the remaining electrolyte. Suppressed. Therefore, even if the chlorine component contained in the sealing member dissolves into the stagnating electrolytic solution, corrosion of the leads can be suppressed. It should be noted that the stagnant electrolytic solution means that a component contained in the electrolytic solution (for example, a solvent or a solution in which an electrolyte salt is dissolved) stays.

The lead may come into contact with the stagnant electrolytic solution not only in the region penetrating the sealing member but also in the region penetrating the mold resin layer. Therefore, if an electrically insulating layer is formed between the lead and the sealing member and/or the mold resin layer (in at least a part of the region where the lead penetrates the sealing member and the mold resin layer), the lead can be An effect of suppressing corrosion can be obtained.

In particular, since the electrolyte tends to stay at the boundary between the sealing member and the mold resin layer, the electrical insulating layer is designed so that at least one of the pair of leads does not come into contact with the boundary between the sealing member and the mold resin layer. (i.e., such that the leads do not face the boundary). In this case, the effect of providing the insulating region can be further enhanced. Furthermore, it is more preferable that the electrical insulating layer is provided across the boundary between the sealing member and the mold resin layer.

Further, if a voltage is applied to the electrolytic capacitor while the pair of leads are in contact with the electrolyte remaining at the boundary between the sealing member and the mold resin layer, corrosion of the leads (especially the anode lead) progresses. do. By providing an electrical insulating layer so that at least one of the pair of leads does not come into contact with the boundary between the sealing member and the mold resin layer, the progress of corrosion of such leads is suppressed. In order to further enhance the effect of suppressing the progress of corrosion of such leads, it is preferable that both of the pair of leads are provided with insulating regions. In addition, in such a state, the metal (for example, aluminum or tin) that constitutes the anode lead is likely to melt out of the anode lead. Therefore, the insulating region may be provided only on the anode lead.

The electrically insulating layer preferably has excellent corrosion resistance to the electrolyte or solvent containing chlorine. In this case, the effect of providing the insulating region can be maintained for a long period of time.

The electrolytic capacitor according to the second embodiment of the present disclosure will be described in detail below with reference to the drawings, but the present disclosure is not limited thereto.

The electrolytic capacitor 2A shown in FIG. 7 includes a capacitor element 10 including an anode foil 21 (see FIG. 2) and a cathode foil 22 (see FIG. 2), and an electrolytic solution (not shown) interposed between the anode foil 21 and the cathode foil 22. ), and a cylindrical case 11 with an opening containing a capacitor element 10 and an electrolytic solution. Examples of materials for the case 11 include metals such as aluminum, stainless steel, copper, iron, brass, and alloys thereof.

The electrolytic capacitor 2</b>A includes a sealing member 12 that seals the opening of the case 11 and a mold resin layer 13 that covers the sealing member 12 . The mold resin layer 13 is provided so as to cover the opening of the case 11 together with the main surface of the sealing member 12 that is arranged outside the case 11 . The opening of case 11 is sealed with sealing member 12 and mold resin layer 13 after accommodating capacitor element 10 . The vicinity of the open end of the case 11 is drawn toward the sealing member 12, and the open end of the case 11 is caulked inward. Thereby, the sealing member 12 is fixed to the opening of the case 11 , and the case 11 is sealed by the sealing member 12 . By providing the mold resin layer 13, deterioration of the sealing member 12 due to oxidation or the like is suppressed, and the sealing performance of the electrolytic capacitor 2A is further improved.

As shown in FIG. 7, it is preferable that the mold resin layer 13 further covers at least a portion of the side surface of the case 11 following the opening. Thereby, the sealing performance of the electrolytic capacitor can be further improved. In this embodiment, the mold resin layer 13, the case 11 and the sealing member 12 may be partially not adhered to each other.

As the mold resin layer 13, the same configuration and material as in the first embodiment can be used.

Electrolytic capacitor 2A includes a pair of leads 14A and 14B electrically connected to anode foil 21 and cathode foil 22 included in capacitor element 10 and penetrating sealing member 12 and mold resin layer 13, respectively. When the electrolytic capacitor is mounted on the substrate, capacitor element 10 is electrically connected to terminals on the substrate via leads 14A and 14B.

Leads 14A and 14B have tab portions 16A and 16B connected to anode foil 21 and cathode foil 22, respectively, and lead portions 15A and 15B connected to tab portions 16A and 16B, respectively. The lead portions 15A, 15B and the tab portions 16A, 16B are connected by welding or the like. The lead portions 15A and 15B contain metal such as iron, copper, nickel, and tin, for example. Tab portions 16A and 16B contain, for example, aluminum.

The tab portions 16A and 16B respectively have rod-shaped portions 17A and 17B and flat portions 18A and 18B. The rod-shaped portions 17A, 17B and the flat portions 18A, 18B may be electrically connected to each other, and may be integrated. For example, by rolling one end of a rod-shaped body to form a flattened portion and leaving the unrolled region as a rod-shaped portion, a tab portion in which the flattened portion and the rod-shaped portion are integrated can be formed.

In this embodiment, the rod-shaped portions 17A and 17B each include a portion arranged inside the sealing member 12 . The lead-out portions 15A and 15B extend from the tip portions of the bar-shaped portions 17A and 17B, respectively. Bar-shaped portions 17A and 17B are connected to capacitor element 10 via flat portions 18A and 18B, respectively. Having the flat portions 18A and 18B facilitates connection between the leads 14A and 14B and the capacitor element.

The shape of the lead-out portions 15A and 15B is not particularly limited, and may be wire-like or ribbon-like, for example. The shape of the rod-shaped portions 17A and 17B is not particularly limited, and may be a round rod shape (for example, a rod shape with a circular or elliptical cross section) or a square rod shape (for example, a rod shape with a polygonal cross section). good too.

Leads 14A and 14B have insulating regions covered by electrically insulating layers 19A and 19B. The electrical insulating layers 19A, 19B are provided between the leads 14A, 14B, the sealing member 12 and the mold resin layer 13. As shown in FIG. By providing the electrical insulating layers 19A and 19B, when the chlorine component contained in the sealing member 12 dissolves into the electrolyte staying inside the sealing member 12 or at the boundary between the sealing member 12 and the mold resin layer 13 However, lead corrosion can be suppressed.

As shown in FIG. 7, the electrical insulating layers 19A and 19B are preferably provided so that the leads 14A and 14B do not contact the boundary between the sealing member 12 and the mold resin layer 13. As shown in FIG. By providing such electrical insulating layers 19A and 19B, the leads 14A and 14B can be prevented from contacting the electrolyte remaining at the boundary between the sealing member 12 and the mold resin layer 13. FIG. Corrosion of the leads 14A and 14B (in particular, the lead 14A on the anode side) can be suppressed when a voltage is applied to the electrolytic capacitor while the leads 14A and 14B are in contact with the electrolytic solution.

As shown in FIG. 7, the electrical insulating layers 19A and 19B are more preferably provided across the boundary between the sealing member 12 and the mold resin layer 13. As shown in FIG. In this case, the effect of preventing the leads 14A and 14B from coming into contact with the electrolyte remaining at the boundary between the sealing member 12 and the mold resin layer 13 can be further enhanced.

The electrical insulating layers 19A and 19B preferably have excellent corrosion resistance to the electrolyte or solvent containing chlorine. In this case, the effect of providing the insulating region can be maintained for a long period of time.

The thickness of the electrically insulating layers 19A and 19B is, for example, 0.01 mm or more and 1.00 mm or less.

When the lead portions 15A and 15B contain a transition metal, the ends of the lead portions 15A and 15B and the bar portions 17A and 17B are fused together when the lead portions 15A and 15B and the bar portions 17A and 17B are welded together. The transition metal is exposed on the surface of the junction. Therefore, when the joint comes into contact with the electrolyte remaining at the boundary between the sealing member 12 and the mold resin layer 13, the joint (especially the joint on the anode side) is likely to be corroded, and the lead is likely to break at the joint. . Therefore, as shown in FIG. 7, it is preferable that at least the junctions between the tab portions 16A and 16B (rod portions 17A and 17B) and the lead portions 15A and 15B are covered with electrical insulating layers 19A and 19B. In other words, it is preferable to provide the insulating region in a region extending from the rod-shaped portions 17A and 17B of the leads 14A and 14B to the lead portions 15A and 15B. By covering the joints with the electrically insulating layer, it is possible to suppress the progress of corrosion of the joints and the accompanying breakage of wires at the joints. As shown in FIG. 1, when the junction is located near the boundary, the junction is likely to come into contact with the electrolyte staying at the boundary. The effect by covering with is obtained notably.

In the present embodiment, as shown in FIG. 7, at least a part of the joints between the tabs 16A and 16B (rod-shaped parts 17A and 17B) and the lead-out parts 15A and 15B is formed between the sealing member 12 and the mold resin layer 13. Although it is positioned closer to the sealing member 12 than the boundary, at least part of the joint may be positioned closer to the mold resin layer 13 than the boundary.

The distances t _1a and t _1b by which the insulating region extends from the boundary between the sealing member 12 and the mold resin layer 13 toward the mold resin layer 13 are preferably 10% or more of the thickness T ₁ of the mold resin layer 13. . In this case, the sealing property of the electrolytic capacitor can be further improved.

In this embodiment, the distances t _1a and t _1b of the insulating regions are such that the electrical insulating layers 19A and 19B extend from the interface between the sealing member 12 and the mold resin layer 13 along the direction perpendicular to the interface. This is the distance extending to the layer 13 side. The thickness T1 of the mold resin layer 13 is the thickness in the axial direction (the X direction in FIG. ₁ ) of the case 11, and is the thickness of the region of the mold resin layer 13, which will be described later, where the grooves 13A and 13B are not provided. is.

The distances t _2a and t _2b by which the insulating region extends from the boundary between the sealing member 12 and the mold resin layer 13 toward the sealing member 12 are preferably 10% or more of the thickness T ₂ of the sealing member 12 . In this case, the sealing property of the electrolytic capacitor can be further improved.

In this embodiment, the distances t _2a and t _2b of the insulating regions are such that the electrical insulating layers 19A and 19B extend from the interface between the sealing member 12 and the mold resin layer 13 to the sealing member along the direction perpendicular to the interface. 12 is the distance extending to the side. The thickness T2 of the sealing member 12 is the thickness in the axial direction (the X direction in _FIG . 1) of the case 11 .

In this embodiment, both the leads 14A and 14B are provided with insulating regions, but one of the leads 14A and 14B may be provided with an insulating region.

(Modification of Second Embodiment)
Although the electrical insulating layers 19A and 19B shown in FIG. 7 are provided in the second embodiment, the electrical insulating layers 29A and 29B shown in FIG. 8 may be provided. By providing the electrical insulating layers 29A and 29B, it is possible to prevent the leads 14A and 14B from coming into contact with the electrolytic solution over the entire region where the leads 14A and 14B penetrate the sealing member 12 and the mold resin layer 13. FIG.

One end of the electrical insulating layers 29A and 29B is exposed from the main surface of the sealing member 12 on the side opposite to the mold resin layer 13 side. In this case, the effect of providing the insulating region can be further enhanced.

The other ends of the electrical insulating layers 29A and 29B are exposed from the mounting surface 13S side of the mold resin layer 13. As shown in FIG. In this case, the effect of providing the insulating region can be further enhanced. However, it is preferable that the electrical insulating layers 29A and 29B are not provided on the portions where the leads 14A and 14B are mounted, in order to improve mountability.

The electrically insulating layers 19A, 19B, 29A, 29B preferably include at least one of an insulating resin layer and an insulating ceramics layer. In this case, an electrically insulating layer having excellent electrical insulation and corrosion resistance to an electrolytic solution (solvent containing a chlorine component) can be obtained.

The insulating resin layer preferably contains a cured product of a curable resin composition, a thermoplastic resin, or a composition containing the same. As the curable resin, for example, those exemplified as materials that can be used for the mold resin layer, such as thermosetting resin, can be used. The curable resin composition may contain a filler, a curing agent, etc. in addition to the curable resin.

Examples of thermosetting resins that can be used include phenol resins, epoxy resins, melamine resins, urea resins, unsaturated polyesters, alkyd resins, polyurethanes, and thermosetting polyimides. Among them, the thermosetting resin is preferably a phenol resin, an epoxy resin, or a thermosetting polyimide.

Examples of thermoplastic resins include fluororesins (e.g., polytetrafluoroethylene), polyamideimides, polyimides, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, ABS resins, AS resins, acrylic resins, and the like. can be used. Among them, the thermoplastic resin is preferably fluororesin, polyamide-imide, or polyimide.

The insulating resin layer may be formed by applying a thermosetting resin composition to a predetermined portion of the lead and then curing it, or by applying a thermoplastic resin (composition) to a predetermined portion of the lead. You may Alternatively, the insulating resin layer may be formed by attaching an insulating resin tape to a predetermined portion of the lead.

The insulating ceramic layer preferably contains silica, metal oxides, carbides, borides, and coupling agents. Silica includes, for example, natural crystalline silica, natural amorphous silica, synthetic crystalline silica, synthetic amorphous silica, and the like. Among them, silica preferably contains synthetic amorphous silica. Metal oxides include, for example, oxides containing aluminum, oxides containing titanium, oxides containing tantalum, and the like. Carbides include, for example, silicon carbide, titanium carbide, boron carbide, and the like. Borides include, for example, aluminum diboride, titanium diboride, and the like. Coupling agents include, for example, silane coupling agents, titanate coupling agents, and the like.

The insulating ceramics layer is formed by, for example, attaching ceramics to a predetermined portion of the lead by an aerosol deposition method, attaching a tape containing ceramics, or applying a paint containing ceramics.

The electrically insulating layer may be formed before inserting the lead into the sealing member or after inserting the lead into the sealing member.

Here, FIGS. 9 and 10 show an example of an electrolytic capacitor in which the electrically insulating layer is formed before the lead is inserted into the sealing member. 9 and 10 are cross-sectional views of essential parts showing the vicinity of the boundary between the sealing member and the mold resin layer in the electrolytic capacitor.

In the case of the electrolytic capacitor shown in FIG. 9, for example, electrically insulating layers 39A and 39B shown in FIG. 9 are provided. After that, the rod-shaped portions 17A and 17B are inserted into the sealing member 12 so that the joints of the drawn-out portions 15A and 15B and the rod-shaped portions 17A and 17B are positioned in the holes of the sealing member 12, and then the mold resin layer 13 is formed. do.

In the case of the electrolytic capacitor shown in FIG. 10, for example, electrically insulating layers 49A and 49B shown in FIG. 10 are provided. After that, the rod-shaped portions 17A and 17B are inserted into the sealing member 12 so that the joints of the drawn-out portions 15A and 15B and the rod-shaped portions 17A and 17B are positioned outside the holes of the sealing member 12, and then the mold resin layer 13 is formed. do.

FIGS. 11 and 12 show examples of electrolytic capacitors in which the electrical insulating layer is formed after the leads are inserted into the sealing member. 11 and 12 are cross-sectional views of essential parts showing the vicinity of the boundary between the sealing member and the mold resin layer in the electrolytic capacitor.

In the case of the electrolytic capacitor shown in FIG. 11, for example, the rod-shaped portions 17A and 17B are inserted into the sealing member 12 so that the joints between the lead-out portions 15A and 15B and the rod-shaped portions 17A and 17B are positioned within the holes of the sealing member 12. . After that, electrical insulating layers 59A and 59B shown in FIG. 11 are provided, and then the mold resin layer 13 is formed.

In the case of the electrolytic capacitor shown in FIG. 12, for example, the rod-shaped portions 17A and 17B are inserted into the sealing member 12 so that the joints between the lead-out portions 15A and 15B and the rod-shaped portions 17A and 17B are positioned outside the holes of the sealing member 12. . After that, electrical insulating layers 69A and 69B shown in FIG. 12 are provided, and then the mold resin layer 13 is formed.

In this embodiment, the electrically insulating layer is not limited to the electrically insulating layers shown in FIGS. 9 to 12. FIG. In this embodiment, if the electrical insulating layer is provided between the lead and the sealing member and/or the mold resin layer, the effect of suppressing corrosion of the lead can be obtained. The electrically insulating layer may be provided between the lead and the sealing member and the mold resin layer (for example, across the boundary between the sealing member and the mold resin layer). Moreover, the electrical insulating layer may be provided only between the leads and the sealing member (the region where the leads penetrate the sealing member), or between the leads and the mold resin layer (the region where the leads penetrate the molding resin). may be provided only for

The lead portions 15A and 15B have portions that are drawn out from the mounting surface 13S side of the mold resin layer 13, and the portions are arranged along the mounting surface 13S of the mold resin layer 13. As shown in FIG.

As shown in FIG. 7, the mounting surface 13S of the mold resin layer 13 is provided with elongated grooves 13A and 13B for accommodating the portions of the leads 14A and 14B drawn out from the mold resin layer 13 (lead portions 15A and 15B). may be provided. By accommodating the lead portions 15A and 15B in the groove portions 13A and 13B, the lead portions 15A and 15B can be stably fixed and arranged near the mounting surface 13S.

The bottom surfaces 13a and 13b of the grooves 13A and 13B gradually extend from one end of the grooves 13A and 13B where the leads 14A and 14B of the grooves 13A and 13B are pulled out from the mold resin layer 13 toward the other end. It is sloping with increasing depth. When the lead portions 15A and 15B are bent so as to be substantially parallel to the mounting surface 13S, a force acts on the lead portions 15A and 15B to return them to their original shapes. In consideration of this point, by inclining the bottom surfaces of the grooves 13A and 13B as described above, the lead-out portions 15A and 15B do not protrude excessively from the mounting surface 13S, and the lead-out portions 15A and 15B are positioned within the grooves 13A and 13B. can be accommodated in The inclination angle of the bottom surfaces of the grooves 13A and 13B with respect to the mounting surface 13S is, for example, 3° or more and 30° or less.

In this embodiment, the bottom surfaces of the grooves 13A and 13B are inclined, but the depths of the grooves 13A and 13B may be constant without making the bottom surfaces of the grooves 13A and 13B inclined.

As the sealing member 12, the same configuration and material as in the first embodiment can be used.

Since the capacitor element 10 is the same as that of the first embodiment, the description thereof is omitted. In addition, in this embodiment, the electric conductivity of the electrolytic solution may be low.

The electrolyte contained in the case may contain a solvent capable of dissolving the chlorine component contained in the sealing member. Therefore, even if the amount of electrolyte (solvent) in the case is small, the leads may corrode. By providing an electrical insulating layer, it is possible to obtain the effect of suppressing such lead corrosion.

(Third embodiment)
The mold resin layer is usually formed in close contact with the sealing member. However, the degree of expansion (linear expansion coefficient) when the temperature rises greatly differs between the mold resin layer and the sealing member. As a result, stress is concentrated near the boundary between the mold resin layer and the sealing member, which may cause cracks in the mold resin layer and degrade the sealing performance of the electrolytic capacitor.

An electrolytic capacitor according to a third embodiment of the present disclosure includes a capacitor element including a pair of electrodes, a case housing the capacitor element, a sealing member, a mold resin layer covering the sealing member, and the sealing member and the mold resin layer. and a pair of leads passing through. The case has an opening. The sealing member seals the opening of the case. A pair of leads are electrically connected to a pair of electrodes, respectively. A gap is provided between the sealing member and the mold resin layer.

By providing the above-mentioned gap, stress is concentrated near the boundary between the mold resin layer and the sealing member even when the degree of expansion (linear expansion coefficient) between the mold resin layer and the sealing member differs greatly when the temperature rises. become difficult. By alleviating the concentration of stress, it is possible to suppress the occurrence of cracks in the mold resin layer. Therefore, it is possible to suppress deterioration of the sealing performance of the electrolytic capacitor due to cracks occurring in the mold resin layer.

The gap is preferably a minute gap formed by the mold resin layer not adhering (adhering) to the sealing member. A minute gap is advantageous for miniaturization of the electrolytic capacitor. In addition, minute gaps can be formed by a method described later.

It is preferable that the molding resin layer further covers at least a portion of the side surfaces of the case that are adjacent to the opening. In this case, the sealing property of the electrolytic capacitor can be further improved. It is preferable that the mold resin layer is in close contact with the case in a region facing the case. In this case, the mold resin layer covering the sealing member can be fixed more firmly.

When the electrolytic capacitor contains an electrolytic solution, it is preferable that a film of a component contained in the electrolytic solution is formed on the surface (exposed surface) of the sealing member exposed in the gap. That is, at least part of the exposed surface is preferably covered with a film of components contained in the electrolytic solution. By covering the exposed surface of the sealing member with a film of a component contained in the electrolytic solution, contact between the sealing member and oxygen is suppressed even when the mold resin layer contains a resin component that relatively easily permeates oxygen. . Therefore, even in a high-temperature environment, deterioration of the sealing member due to contact between the oxygen permeating the mold resin layer and the sealing member is suppressed.

When an electrolytic capacitor is provided with an electrolytic solution interposed between a pair of electrodes, and the electrolytic solution is housed in a case, the film of the component contained in the electrolytic solution is formed by the electrolyte contained in the case. component permeates the sealing member and stays in the gap between the sealing member and the mold resin layer. When an electrolytic capacitor has an electrolytic solution interposed between a pair of electrodes and the electrolytic solution is housed in a case, components contained in the electrolytic solution (e.g., solvent) relatively easily permeate through the sealing member. However, it is difficult to permeate the mold resin layer. Therefore, by providing a gap between the sealing member and the mold resin layer, components of the electrolytic solution that have permeated the sealing member tend to stay in the gap between the sealing member and the mold resin layer. Therefore, a film of components of the electrolytic solution can be efficiently formed on the exposed surface of the sealing member.

One of the pair of electrodes is the anode and the other is the cathode. The anode has a dielectric layer on its surface. One of the pair of leads is an anode lead electrically connected to the anode and the other is a cathode lead electrically connected to the cathode. A pair of leads passing through the sealing member and the mold resin layer are exposed in a gap provided between the sealing member and the mold resin layer. Therefore, at least one of the pair of leads preferably has an insulating region covered with an electrically insulating layer. More preferably, the insulating region is provided across at least the gap. That is, it is more preferable that the insulating region is provided so as to pass through (straddle) the gap between the portion where the lead penetrates the sealing member and the portion where the lead penetrates the mold resin layer.

By providing the insulating region, even when a film of components contained in the electrolytic solution is formed in the gap between the sealing member and the mold resin layer (components contained in the electrolytic solution remain), the pair of leads and Contact with components of the electrolytic solution is suppressed. If a voltage is applied to the electrolytic capacitor while the pair of leads are in contact with the components of the electrolytic solution, corrosion of the leads (especially the anode lead) progresses. By providing the insulating region, progress of such corrosion is suppressed.

Even when the insulating region is provided only on one of the pair of leads, it is possible to suppress the progress of corrosion as described above. However, in order to further enhance the effect of suppressing the progress of lead corrosion, it is preferable that both of the pair of leads are provided with insulating regions.

It is preferable that the electrical insulating layer has excellent electrolyte resistance. In this case, the effect of providing the insulating region can be maintained for a long period of time. The electrically insulating layer preferably includes, for example, at least one of an insulating resin layer and an insulating ceramics layer.

The electrolytic capacitor may include an electrolytic solution interposed between the pair of electrodes, and the electrolytic solution may be accommodated in the case. The electrolytic capacitor may comprise a solid electrolyte layer covering at least part of the surface of the dielectric layer. The electrolytic capacitor may comprise both the electrolyte and solid electrolyte layers described above.

The electrolytic capacitor according to the third embodiment of the present disclosure will be described in detail below with reference to the drawings, but the present disclosure is not limited thereto.

The electrolytic capacitor 3A shown in FIG. 13 has a capacitor element 10 including an anode foil 21 (see FIG. 2) and a cathode foil 22 (see FIG. 2), and an electrolytic solution interposed between the anode foil 21 and the cathode foil 22 (see FIG. 2). ), and a cylindrical case 11 with an opening containing a capacitor element 10 and an electrolytic solution. Examples of materials for the case 11 include metals such as aluminum, stainless steel, copper, iron, brass, and alloys thereof.

The electrolytic capacitor 3</b>A includes a sealing member 12 that seals the opening of the case 11 and a mold resin layer 13 that covers the sealing member 12 . The mold resin layer 13 is provided so as to cover the opening of the case 11 together with the main surface of the sealing member 12 that is arranged outside the case 11 . The opening of case 11 is sealed with sealing member 12 and mold resin layer 13 after accommodating capacitor element 10 . The vicinity of the open end of the case 11 is drawn toward the sealing member 12, and the open end of the case 11 is caulked inward. Thereby, the sealing member 12 is fixed to the opening of the case 11 , and the case 11 is sealed by the sealing member 12 . By providing the mold resin layer 13, the sealing performance of the electrolytic capacitor 3A is further enhanced.

The mold resin layer 13 is not adhered to the sealing member 12 in the region facing the sealing member 12 , and a minute gap 20 is formed between the mold resin layer 13 and the sealing member 12 . By providing the gap 20, even if the degree of expansion (linear expansion coefficient) between the mold resin layer 13 and the sealing member 12 is greatly different from that of the mold resin layer 13 when the temperature rises, stress is applied to the vicinity of the boundary between the mold resin layer 13 and the sealing member 12. becomes difficult to concentrate. By alleviating stress concentration, it is possible to suppress the occurrence of cracks in the mold resin layer 13 .

As shown in FIG. 13, the mold resin layer 13 preferably further covers at least a portion of the side surfaces of the case 11 that are adjacent to the opening. Thereby, the sealing property of the electrolytic capacitor 3A can be further improved.

Mold resin layer 13 is adhered to case 11 in a region facing case 11 . As a result, the mold resin layer 13 covering the sealing member 12 can be firmly fixed. In the present embodiment, the mold resin layer 13 may be partially adhered to the case 11 in the region facing the case 11, and may not be adhered to some portions.

As the mold resin layer 13, the same configuration and material as in the first embodiment can be used.

As a method of providing the gap 20 between the sealing member 12 and the mold resin layer 13, for example, when molding the mold resin layer 13, a predetermined region of the sealing member 12 (region covered with the mold resin layer 13) Application of a release agent may be mentioned. As a result, the mold resin layer 13 does not adhere to the sealing member 12, so that a minute gap can be easily formed. As the release agent, for example, a silicone-based or fluorine-based release agent is used.

A film (not shown) of a component contained in the electrolytic solution is preferably formed on the surface (exposed surface) of the sealing member 12 exposed in the gap 20 . For example, it is possible to form a film of the components contained in the electrolyte so as to cover at least part of the exposed surface of the sealing member 12 by causing the components of the electrolyte that have passed through the sealing member 12 to remain in the gap 20 . can.

Since the exposed surface of the sealing member 12 is covered with a film of components contained in the electrolytic solution, even if oxygen from the outside permeates the mold resin layer 13 and reaches the gap 20, the sealing member 12 and the oxygen contact with each other. is suppressed. Therefore, deterioration of the sealing member 12 due to contact between oxygen and the sealing member 12 is suppressed even in a high-temperature environment.

The electrolytic capacitor includes a pair of leads 14A, 14B electrically connected to anode foil 21 and cathode foil 22 included in capacitor element 10, respectively, and penetrating sealing member 12 and mold resin layer 13. As shown in FIG. When the electrolytic capacitor is mounted on the substrate, capacitor element 10 is electrically connected to terminals on the substrate via leads 14A and 14B.

Leads 14A and 14B have tab portions 16A and 16B connected to anode foil 21 and cathode foil 22, respectively, and lead portions 15A and 15B connected to tab portions 16A and 16B, respectively. The lead portions 15A, 15B and the tab portions 16A, 16B are connected by welding or the like. The lead portions 15A and 15B contain metal such as iron, copper, nickel, and tin, for example. Tab portions 16A and 16B contain, for example, aluminum.

The tab portions 16A and 16B respectively have rod-shaped portions 17A and 17B and flat portions 18A and 18B. The rod-shaped portions 17A, 17B and the flat portions 18A, 18B may be electrically connected to each other, and may be integrated. For example, by rolling one end of a rod-shaped body to form a flattened portion and leaving the unrolled region as a rod-shaped portion, a tab portion in which the flattened portion and the rod-shaped portion are integrated can be formed.

The rod-shaped portions 17A and 17B each include a portion penetrating through the sealing member 12 . The shape of the rod-shaped portions 17A and 17B is not particularly limited, and may be a round rod shape (for example, a rod shape with a circular or elliptical cross section) or a square rod shape (for example, a rod shape with a polygonal cross section). good too. Bar-shaped portions 17A and 17B are connected to capacitor element 10 via flat portions 18A and 18B, respectively. Having the flat portions 18A and 18B facilitates connection between the leads 14A and 14B and the capacitor element.

Each of the lead portions 15A and 15B includes a portion penetrating through the mold resin layer 13 . The shape of the lead-out portions 15A and 15B is not particularly limited, and may be wire-like or ribbon-like, for example. The lead-out portions 15A and 15B extend from the tip portions of the bar-shaped portions 17A and 17B, respectively.

Here, an example of an electrolytic capacitor in which a gap is formed in a state in which the rod-shaped portion is inserted into the hole of the sealing member so that the joint portion between the lead-out portion and the rod-shaped portion is positioned within the hole of the sealing member is shown in FIG. 14. FIG. 14 is a cross-sectional view of essential parts showing the vicinity of the boundary between the sealing member and the mold resin layer in the electrolytic capacitor.

As shown in FIG. 14, the rod-shaped portions 17A and 17B are inserted into the holes of the sealing member 12 so that the joints of the drawer portions 15A and 15B and the rod-shaped portions 17A and 17B are positioned within the holes of the sealing member 12. . The tip portions of the bar-shaped portions 17A and 17B are exposed from the sealing member 12 on the mold resin layer 13 side. A gap 30 is provided between the tip portions of the rod-shaped portions 17A and 17B and the sealing member 12 and the mold resin layer 13 .

The gap 30 is formed, for example, by the following method. The rod-shaped portions 17A and 17B are inserted into the holes of the sealing member 12 so that the joints of the drawer portions 15A and 15B and the rod-shaped portions 17A and 17B are positioned within the holes of the sealing member 12 . After that, when molding the mold resin layer 13, a release agent is applied to the tip portions of the rod-shaped portions 17A and 17B and predetermined regions of the sealing member 12 (regions covered with the mold resin layer 13).

FIG. 15 shows an example of an electrolytic capacitor in which a gap is formed in a state where the rod-shaped portion is inserted into the hole of the sealing member so that the joint portion between the lead-out portion and the rod-shaped portion is positioned outside the hole of the sealing member. shown in FIG. 15 is a cross-sectional view of essential parts showing the vicinity of the boundary between the sealing member and the mold resin layer in the electrolytic capacitor.

As shown in FIG. 15, the rod-shaped portions 17A and 17B are inserted into the holes of the sealing member 12 so that the joints of the drawer portions 15A and 15B and the rod-shaped portions 17A and 17B are positioned outside the hole of the sealing member 12. . The tip portions of the bar-shaped portions 17A and 17B are exposed from the sealing member 12 on the mold resin layer 13 side. A gap 40 is provided between the tip portions of the rod-shaped portions 17A and 17B and the sealing member 12 and the mold resin layer 13 .

The gap 40 is formed, for example, by the following method. The rod-shaped portions 17A and 17B are inserted into the holes of the sealing member 12 so that the joints of the drawer portions 15A and 15B and the rod-shaped portions 17A and 17B are positioned within the holes of the sealing member 12 . After that, when molding the mold resin layer 13, a release agent is applied to the tip portions of the rod-shaped portions 17A and 17B and predetermined regions of the sealing member 12 (regions covered with the mold resin layer 13).

As shown in FIGS. 14 and 15, when the tip portions of the rod-shaped portions 17A and 17B are exposed from the sealing member 12 on the mold resin layer 13 side, there is a gap between the tip portions of the rod-shaped portions 17A and 17B and the mold resin layer 13. , a gap continuing to the gap formed between the sealing member 12 and the mold resin layer 13 may be further formed.

(Modified example of the third embodiment)
Parts of the leads 14A and 14B are exposed in a gap 20 provided between the sealing member 12 and the mold resin layer 13. As shown in FIG. Therefore, as shown in FIG. 16, leads 14A and 14B preferably have insulating regions covered with electrically insulating layers 19A and 19B. It is preferable that the insulating region is provided over at least the gap 20 . That is, the insulating region is preferably provided so as to pass through (straddle) the gap 20 from the portion where the leads 14A and 14B penetrate the sealing member 12 to the portion where the mold resin layer 13 is penetrated.

By providing the insulating region, even if a film of components contained in the electrolytic solution is formed on the surface of the sealing member 12 exposed in the gap 20 (when components contained in the electrolytic solution remain in the gap 20), the leads 14A , 14B and the components of the electrolyte are suppressed. Therefore, the progress of corrosion of the leads 14A and 14B (in particular, the lead 14A on the anode side) is suppressed.

In FIG. 16, both the leads 14A and 14B are provided with insulating regions, but one of the leads 14A and 14B may be provided with an insulating region.

When the lead-out portions 15A and 15B contain a transition metal, the ends of the lead-out portions 15A and 15B and the bar-shaped portions 17A and 17B are fused together when the lead-out portions 15A and 15B and the rod-shaped portions 17A and 17B are welded together. The transition metal is exposed on the surface of the junction. Therefore, when the joint comes into contact with the components of the electrolyte remaining in the gap 20, the joint (especially the joint on the anode side) is likely to be corroded, and the lead is likely to break at the joint. Therefore, as shown in FIG. 16, it is preferable that at least the junctions between the tab portions 16A and 16B (rod portions 17A and 17B) and the lead portions 15A and 15B are covered with electrical insulating layers 19A and 19B. In other words, it is preferable to provide the insulating region in a region extending from the rod-shaped portions 17A and 17B of the leads 14A and 14B to the lead portions 15A and 15B. By covering the joints with the electrically insulating layer, it is possible to suppress the progress of corrosion of the joints and the accompanying breakage of wires at the joints. As shown in FIG. 16, when the joints are positioned near the gap 20, they are likely to come into contact with the components of the electrolytic solution remaining in the gaps 20. Therefore, the joints should be covered with the electrically insulating layers 19A and 19B. The effect of is obtained remarkably.

Distances t _1a and t _1b by which the insulating region extends from the boundary between mold resin layer 13 and gap 20 toward mold resin layer 13 are preferably 10% or more of thickness T ₁ of mold resin layer 13 . In this case, the effect of providing the insulating region can be further enhanced.

In this embodiment, the distances t _1a and t _1b of the insulating regions are such that the electrical insulating layers 19A and 19B extend from the interface between the mold resin layer 13 and the gap 20 along the direction perpendicular to the interface. This is the distance extending to the 13 side. _The thickness T1 of the mold resin layer 13 is the thickness in the axial direction (the X direction in FIG. 16) of the case 11, and is the thickness of the region of the mold resin layer 13 where the grooves 13A and 13B described later are not provided. is.

Distances t _2a and t _2b by which the insulating region extends from the boundary between the sealing member 12 and the gap 20 toward the sealing member 12 are preferably 10% or more of the thickness T ₂ of the sealing member 12 . In this case, the effect of providing the insulating region can be further enhanced.

In the present embodiment, the distances t _2a and t _2b of the insulating regions are such that the electrical insulating layers 19A and 19B extend from the boundary surface between the sealing member 12 and the gap 20 to the sealing member 12 side along the direction perpendicular to the boundary surface. is the distance that extends to The thickness T2 of the sealing member 12 is the thickness in the axial direction (the X direction in _FIG . 16) of the case 11 .

From the viewpoint of maintaining the effect of providing the insulating region over a long period of time, the electrically insulating layers 19A and 19B preferably include an insulating resin layer and/or an insulating ceramic layer that are excellent in electrolyte resistance. The thickness of the electrical insulating layers 19A and 19B may be, for example, 0.01 mm or more and 1.00 mm or less.

As the insulating resin layer and the insulating ceramic layer, the same configurations and materials as in the second embodiment can be used. The insulating ceramic layer is formed by, for example, attaching ceramics to a predetermined portion of the lead by an aerosol deposition method, attaching a tape containing ceramics, or applying a paint containing ceramics. .

In FIG. 13, the lead portions 15A and 15B have portions that are led out from the mounting surface 13S side of the mold resin layer 13 to the outside. The portion is arranged along the mounting surface 13S of the mold resin layer 13 . Here, on the mounting surface 13S of the mold resin layer 13, as shown in FIG. 13, elongated grooves 13A and 13B are formed to accommodate the portions of the leads 14A and 14B that are drawn out from the mold resin layer 13. As shown in FIG. may be provided. By accommodating the lead portions 15A and 15B in the groove portions 13A and 13B, the lead portions 15A and 15B can be stably fixed and arranged near the mounting surface 13S.

The bottom surfaces 13a and 13b of the grooves 13A and 13B gradually extend from one end of the grooves 13A and 13B where the leads 14A and 14B of the grooves 13A and 13B are pulled out from the mold resin layer 13 toward the other end. It is sloping with increasing depth. When the lead portions 15A and 15B are bent so as to be substantially parallel to the mounting surface 13S, a force acts on the lead portions 15A and 15B to return them to their original shapes. In consideration of this point, by inclining the bottom surfaces of the grooves 13A and 13B as described above, the lead-out portions 15A and 15B do not protrude excessively from the mounting surface 13S, and the lead-out portions 15A and 15B do not protrude from the groove portions 13A and 13B. can be accommodated inside. The inclination angles of the bottom surfaces 13a and 13b of the grooves 13A and 13B with respect to the mounting surface 13S are, for example, 3° or more and 30° or less.

In this embodiment, the bottom surfaces of the grooves 13A and 13B are inclined, but the depths of the grooves 13A and 13B may be constant without making the bottom surfaces of the grooves 13A and 13B inclined.

As the sealing member 12, the same configuration and material as in the first embodiment can be used.

Since the capacitor element 10 is the same as that of the first embodiment, the description thereof is omitted. Capacitor element 10 may include an electrolytic solution and a solid electrolyte layer.

INDUSTRIAL APPLICABILITY The present disclosure is useful in an electrolytic capacitor containing an electrolytic solution in a case and provided with a sealing member and a mold resin layer.

1A, 1B, 1C, 1D, 2A, 2B, 3A, 3B: electrolytic capacitor 10: capacitor element 11: case 12: sealing member 13: mold resin layer 13S: mounting surfaces 13A, 13B: grooves 13a, 13b: bottom surface 14A, 14B: Leads 15A, 15B: Drawer portions 16A, 16B: Tab portions 17A, 17B: Rod-shaped portions 18A, 18B: Flat portions 19A, 19B, 29A, 29B, 39A, 39B, 49A, 49B, 59A, 59B, 69A, 69B : Electrical insulation layers 20, 30, 40: Gap 21: Anode, anode foil 22: Cathode, cathode foil 23: Separator 24: Winding stop tape 175A, 175B: Inner lead connection

Claims (3)

a capacitor element including a pair of electrodes;
an electrolytic solution interposed between the pair of electrodes;
a case containing the capacitor element and the electrolytic solution and having an opening;
a sealing member that seals the opening;
a pair of leads electrically connected to the pair of electrodes and passing through the sealing member;
a mold resin layer covering at least part of the outer surface of the sealing member facing the opening side,
at least one of the pair of leads has a tab portion connected to one of the pair of electrodes and a lead portion connected to one end of the tab portion,
The electrolytic capacitor, wherein the one end of the tab portion protrudes from the outer surface of the sealing member and has an exposed portion that is not covered with the mold resin layer . 2. The electrolytic capacitor according to claim 1 , wherein said tab portion is covered with an oxide film of a metal forming said tab portion. 3. The electrolytic capacitor according to claim 1, wherein said lead portion contains a transition metal.

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