WO2023074375A1

WO2023074375A1 - Electrolytic capacitor and method for manufacturing electrolytic capacitor

Info

Publication number: WO2023074375A1
Application number: PCT/JP2022/038076
Authority: WO
Inventors: 正典柏原; 敦加藤
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2021-10-28
Filing date: 2022-10-12
Publication date: 2023-05-04

Abstract

The disclosed manufacturing method is for an electrolytic capacitor that includes a capacitor element. The manufacturing method includes, in this order: a step (i) for electrically connecting a positive-electrode lead terminal to a positive-electrode part, and electrically connecting a negative-electrode lead terminal to a negative-electrode part; and, a step (ii) for covering a portion of the positive-electrode lead terminal, a portion of the negative-electrode lead terminal, and the capacitor element with an exterior body containing a resin. The manufacturing method further includes, prior to step (ii), a plasma process step in which at least a portion of a metal surface of at least one lead terminal selected from the group consisting of the positive-electrode lead terminal and the negative-electrode lead terminal is subjected to a plasma process, thereby making the at least a portion a plasma process surface, whereby a method for manufacturing an electrolytic capacitor having high reliability is provided.

Description

Electrolytic capacitor and method for manufacturing electrolytic capacitor

The present disclosure relates to electrolytic capacitors and manufacturing methods thereof.

An electrolytic capacitor includes a capacitor element, lead terminals (anode lead terminal and cathode lead terminal) connected to the capacitor element, and an exterior body. The exterior body contains resin and covers a part of the lead terminal and the capacitor element. A problem with electrolytic capacitors is that moisture and oxygen enter from the outside and deteriorate the characteristics of the capacitor element.

The problem with electrolytic capacitors is that moisture and oxygen enter from the outside and degrade the characteristics of the capacitor element. In particular, moisture and oxygen are likely to reach the capacitor element through the surfaces of the lead terminals. Therefore, it is important to improve the adhesion between the package and the lead terminals. Conventionally, there have been proposed techniques for improving the adhesion between the package and the lead terminals.

Patent Document 1 (Japanese Unexamined Patent Application Publication No. 5-021290) describes that ``an anodized film formed on a plate or foil made of a valve metal is used as a dielectric, and a dielectric polymer layer and a dielectric A capacitor element is formed by sequentially forming layers, a lead frame serving as a lead-out terminal is connected to the valve metal portion and the conductor layer portion of the capacitor element, and a part of the capacitor element and the lead frame is molded resin. In the solid electrolytic capacitor to be packaged, a solder alloy layer or a tin metal layer with a copper metal layer as a base is formed on the surface of the lead frame other than the portion in contact with the mold resin, and the lead frame portion in contact with the mold resin A solid electrolytic capacitor characterized by forming only a copper metal layer and roughening the surface of the copper metal layer."

JP-A-5-021290

One aspect of the present disclosure relates to a method for manufacturing an electrolytic capacitor. The manufacturing method is a method for manufacturing an electrolytic capacitor including a capacitor element having an anode portion and a cathode portion, wherein an anode lead terminal is electrically connected to the anode portion and a cathode lead terminal is electrically connected to the cathode portion. and a step (ii) of covering a part of the anode lead terminal, a part of the cathode lead terminal, and the capacitor element with an exterior body containing resin in this order, Before the step (ii), plasma treatment is applied to at least part of the metal surface of at least one lead terminal selected from the group consisting of the anode lead terminal and the cathode lead terminal, so that the at least part is exposed to plasma. The method further includes a plasma treatment step of treating the surface to be treated, wherein in the step (ii), at least part of the plasma treated surface is covered with the exterior body.

Another aspect of the present disclosure relates to electrolytic capacitors. The electrolytic capacitor includes a capacitor element including an anode portion and a cathode portion, and lead terminals including an anode lead terminal electrically connected to the anode portion and a cathode lead terminal electrically connected to the cathode portion. , an exterior body covering a part of the lead terminal and the capacitor element and containing a resin, wherein at least part of a surface of the lead terminal that is in contact with the exterior body is 1 is a plasma treated surface that has been plasma treated.

According to the present disclosure, a highly reliable electrolytic capacitor can be obtained.

FIG. 1 is a cross-sectional view schematically showing an example of one step of the manufacturing method of Embodiment 1. FIG. FIG. 2 is a cross-sectional view schematically showing an example of a process following the process shown in FIG.

Prior to the description of the embodiments, the problems in the prior art will be briefly described below.

Currently, there is a demand for further improvements in the reliability of electrolytic capacitors. In view of the above problems, one object of the present disclosure is to provide an electrolytic capacitor with higher reliability.

Embodiments according to the present disclosure will be described below with examples, but the present disclosure is not limited to the examples described below. In the following description, specific numerical values and materials may be exemplified, but other numerical values and other materials may be applied as long as the invention according to the present disclosure can be implemented. In this specification, the description "numerical value A to numerical value B" includes numerical value A and numerical value B, and can be read as "numerical value A or more and numerical value B or less". In the following description, when lower and upper limits of numerical values relating to specific physical properties and conditions are exemplified, any of the illustrated lower limits and any of the illustrated upper limits can be arbitrarily combined as long as the lower limit is not equal to or greater than the upper limit. .

(Manufacturing method of electrolytic capacitor)
A manufacturing method according to an embodiment of the present disclosure is a manufacturing method of an electrolytic capacitor including a capacitor element having an anode portion and a cathode portion. The manufacturing method may be hereinafter referred to as “manufacturing method (M)”. Manufacturing method (M) includes step (i) and step (ii) in this order, and further includes a plasma treatment step. These steps are described below.

(Step (i))
Step (i) is a step of electrically connecting the anode lead terminal to the anode portion of the capacitor element and electrically connecting the cathode lead terminal to the cathode portion of the capacitor element. Hereinafter, the anode lead terminal and the cathode lead terminal may be collectively referred to as "lead terminals".

There is no particular limitation on the method of connecting the lead terminal and the capacitor element, and a known method may be used for connection. For example, the anode lead terminal and the anode part (eg, anode wire) may be connected by welding. The cathode lead terminal and the cathode section may be connected by a conductive layer. The conductive layer may be formed using a metal paste (eg, silver paste) containing metal particles (eg, silver particles) and resin.

(Plasma treatment process)
A plasma treatment step is performed before step (ii). For example, the plasma treatment step may be performed before step (i) or after step (i) and before step (ii). The plasma treatment step is a step of subjecting at least a portion of the metal surface of at least one lead terminal selected from the group consisting of an anode lead terminal and a cathode lead terminal to a plasma treatment, thereby making the at least a portion a plasma-treated surface. is. Hereinafter, the surface of the metal surface of the lead terminal that is subjected to plasma treatment may be referred to as the "treated surface".

By applying plasma treatment, the surface to be treated can be made hydrophilic and the surface to be treated can be cleaned. By making the surface to be treated hydrophilic, it is possible to make it easier for the resin in the exterior body to adsorb to the surface to be treated. As a result, the adhesion of the exterior body to the surface to be treated can be improved. Further, by cleaning the surface to be treated to remove deposits (for example, organic substances) present on the surface to be treated, the adhesion of the exterior body to the surface to be treated (lead terminal surface) can be improved. By improving the adhesion between the outer package and the surface of the lead terminal, it is possible to suppress the intrusion of moisture and oxygen from the outside through the surface of the lead terminal. As a result, long-term deterioration of the capacitor element can be suppressed, and the reliability of the electrolytic capacitor can be improved.

The plasma processing conditions can be selected according to the purpose, and known plasma processing conditions may be adopted. When the surface to be treated is hydrophilized, for example, atmospheric pressure low temperature plasma treatment may be used. By hydrophilizing the surface to be treated (metal surface) by plasma treatment, hydrophilic groups (for example, hydroxyl groups, carbonyl groups, carboxyl groups, etc.) are introduced into the surface to be treated.

Atmospheric pressure low temperature plasma treatment may be performed under known conditions. Nitrogen gas, argon gas, hydrogen gas, helium gas, or oxygen gas may be used as the plasma gas of the atmospheric pressure low-temperature plasma. good too. An example of processing conditions for atmospheric pressure low temperature plasma is shown below.

Nitrogen gas pressure: 0.3 to 0.5 MPa
Nitrogen gas flow rate: 20 to 30 L/min Irradiation distance: 5 to 30 mm
Moving speed of the plasma generating part or the object to be treated (lead terminal): 10 to 50 mm/sec When cleaning the surface to be treated by plasma treatment, the plasma treatment may be performed under known plasma cleaning conditions.

When the plasma treatment is performed after step (i), the plasma treatment is performed with the lead terminal connected to the capacitor element. When plasma treatment is performed before step (i), plasma treatment may be performed on the metal sheet including portions to be a plurality of lead terminals. The metal sheet to be plasma-treated may be pre-punched and/or bent according to the shape of the lead terminal, or may be a metal sheet before these processes. Plasma treatment of the metal sheet results in a plasma treated surface on the surface of the lead terminal included therein. When the metal sheet is plasma-treated, only one side of the metal sheet may be plasma-treated, or both sides of the metal sheet may be plasma-treated.

(Step (ii))
Step (ii) is a step of covering a portion of the anode lead terminal, a portion of the cathode lead terminal, and the capacitor element with an exterior body containing a resin. In step (ii), at least part of the plasma-treated surface is covered with an outer covering.

There is no particular limitation on step (ii), and a known method may be adopted. For example, an exterior body may be formed by a predetermined method (transfer molding, injection molding, or the like) using a resin composition for the exterior body.

An electrolytic capacitor is obtained by step (ii). When a plurality of electrolytic capacitors are collectively formed at once, each electrolytic capacitor is separated after step (ii), if necessary.

Of the surfaces of the lead terminals, 30% or more, 50% or more, or 80% or more of the surfaces in contact with the outer package are preferably plasma-treated surfaces. All of the surfaces of the lead terminals that come into contact with the outer package may be plasma-treated surfaces.

In the manufacturing method (M), the following conditions (1) and (2) may be satisfied.
(1) The resin contained in the exterior body contains at least one selected from the group consisting of epoxy resins and phenol resins. For example, the resin contained in the exterior body may contain epoxy resin, phenol resin, or both.
(2) In step (i), the plasma-treated surface is hydrophilized by plasma treatment.

Epoxy resins and phenolic resins are particularly prone to adsorption on hydrophilic metal surfaces. Therefore, when the conditions (1) and (2) are satisfied, the adhesion between the outer package and the lead terminals can be particularly improved.

When the above condition (1) is satisfied, the ratio of the at least one resin of condition (1) in the exterior body may be 3% by mass or more, 5% by mass or more, or 10% by mass or more, It may be 100% by mass or less, 40% by mass or less, or 20% by mass or less. For example, the percentage may be in the range of 3% to 40%, 3% to 20%, or 5% to 20% by weight.

When the above condition (2) is satisfied, for example, when the above conditions (1) and (2) are satisfied, the following condition (3) is preferably satisfied. Urethane resins also tend to be adsorbed to hydrophilic metal surfaces. Therefore, by satisfying the conditions (2) and (3), the adhesion between the conductive layer and the cathode lead terminal is improved, and the contact resistance can be reduced.
(3) In step (ii), the cathode lead terminal is connected to the cathode portion by a conductive layer containing metal particles and a resin containing at least one selected from the group consisting of epoxy resin, urethane resin, and phenol resin. . Additionally, a portion of the plasma-treated surface contacts the conductive layer.

When the above condition (3) is satisfied, the conductive layer may contain an epoxy resin, a urethane resin, a phenol resin, or two of them. , may include all three of them. When the above condition (3) is satisfied, the proportion of the at least one resin in the condition (3) in the conductive layer is in the range of 1% by mass to 50% by mass (for example, the range of 3% by mass to 20% by mass). may be in

After performing the plasma treatment step, step (ii) is preferably performed within 72 hours, and step (ii) may be performed within 48 hours or 24 hours. Plasma treated surfaces become less effective over time when left in the atmosphere. Therefore, it is preferable to perform step (ii) while the effect of the plasma-treated surface is sufficiently obtained. If the step (ii) is not performed within 72 hours after the plasma treatment, the lead terminals that have undergone the plasma treatment step (for example, the metal sheet including the part that will become the lead terminal) are placed under reduced pressure and/or at a low temperature ( For example, it is preferably stored at 20° C. or lower. At this time, it is preferable to store the metal sheet including the portions to be the plurality of lead terminals in a state in which the plurality of metal sheets are stacked.

The lead terminal may be composed of only the base material, or may include the base material and a metal layer (for example, a plated layer) formed on the surface of the base material. The metal surface to be plasma treated may contain at least one selected from the group consisting of copper, gold, nickel, tin, lead, bismuth, silver, zinc, iron, chromium, and palladium.

The manufacturing method (M) may further include a step of roughening at least part of the surface of the lead terminal before step (i) and before the plasma treatment step. In that case, it is preferable to subject at least part of the roughened surface to plasma treatment in the plasma treatment step. With this configuration, the area of the surface to be plasma treated can be increased. This configuration also provides the anchoring effect of the roughened surface. Due to these effects, the adhesion between the outer package and the lead terminals can be particularly enhanced.

The roughening method is not particularly limited, and a known sandblasting method, etching method, or the like may be used. Alternatively, the surface of the lead terminal may be roughened by irradiating the lead terminal with laser light (for example, pulsed laser light).

(Electrolytic capacitor)
An electrolytic capacitor according to an embodiment of the present disclosure will be described below. The electrolytic capacitor may be hereinafter referred to as "electrolytic capacitor (C)". Although the method for manufacturing the electrolytic capacitor (C) is not limited, it can be manufactured by the manufacturing method (M). Since the matters described for the manufacturing method (M) can be applied to the electrolytic capacitor (C), redundant description may be omitted. Also, the matters described for the electrolytic capacitor (C) may be applied to the manufacturing method (M).

The electrolytic capacitor (C) includes a capacitor element, lead terminals, and an exterior body. The capacitor element includes an anode portion and a cathode portion. The lead terminals include an anode lead terminal electrically connected to the anode section and a cathode lead terminal electrically connected to the cathode section. The exterior body covers a portion of the lead terminal and the capacitor element. The exterior body contains resin. At least part of the surface of the lead terminal that is in contact with the outer package is a plasma-treated surface.

As described with respect to the manufacturing method (M), according to the electrolytic capacitor (C), it is possible to improve the adhesion between the exterior body and the lead terminals. As a result, it is possible to realize an electrolytic capacitor that is less likely to deteriorate due to moisture, oxygen, or the like, and has high reliability.

The resin contained in the exterior body preferably contains at least one selected from the group consisting of epoxy resins and phenol resins. In that case, the plasma-treated surface may have hydrophilic groups, and the resin of the exterior body (for example, the at least one resin described above) may be adsorbed to the plasma-treated surface via the hydrophilic groups. As described above, according to this configuration, the adhesion between the outer package and the lead terminals can be particularly enhanced. The adsorption of the resin to the plasma-treated surface includes chemical adsorption and physical adsorption. Chemisorption is adsorption through chemical bonds, and includes, for example, the reaction of hydrophilic groups formed on the plasma-treated surface with resin to form bonds.

As described above, the cathode lead terminal may be connected to the cathode portion by a conductive layer containing metal particles and a resin containing at least one selected from the group consisting of epoxy resin, urethane resin, and phenol resin. In that case, the plasma-treated surface may have hydrophilic groups, and the resin of the conductive layer (for example, the at least one resin described above) may be adsorbed to the plasma-treated surface via the hydrophilic groups.

As described above, at least part of the surface of the lead terminal may be roughened, and at least part of the plasma-treated surface may be roughened.

An example of the configuration and components of the electrolytic capacitor manufactured by the manufacturing method (M) and the electrolytic capacitor (C) will be described below. An example electrolytic capacitor described below includes a capacitor element, an outer casing, an anode lead terminal, and a cathode lead terminal. The configuration and components of the electrolytic capacitor manufactured by the manufacturing method (M) and the electrolytic capacitor (C) are not limited to the following examples.

(capacitor element)
A capacitor element includes an anode portion, a dielectric layer, and a cathode portion. There is no particular limitation on the capacitor element, and capacitor elements used in known solid electrolytic capacitors may be used.

The anode part includes an anode body and may further include an anode wire. The anode body may be a porous sintered body or a metal foil with a porous surface. A dielectric layer is formed on at least a portion of the surface of the anode body. The cathode section includes an electrolyte layer and a cathode extraction layer. The electrolyte layer is arranged between the dielectric layer formed on the surface of the anode body and the cathode extraction layer. These components are not particularly limited, and components used in known solid electrolytic capacitors may be applied. Examples of these components are described below.

(Anode body)
A valve action metal can be used as the material of the anode body. Titanium (Ti), tantalum (Ta), niobium (Nb), aluminum (Al), and alloys containing these are used as valve metals. The anode body may be formed by sintering material particles (for example, valve metal particles) or by etching material metal. The dielectric layer formed on the surface of the anode body may be formed by subjecting the surface of the anode body to chemical conversion treatment. The chemical conversion treatment method is not limited, and a known chemical conversion treatment method may be applied.

(anode wire)
When the anode body is a sintered body, the anode portion can include an anode wire. The anode wire may be a wire made of metal. Examples of anode wire materials include the valve metals and copper described above. A portion of the anode wire is embedded in the anode body and the remaining portion protrudes from the end face of the anode body.

(Electrolyte layer)
The electrolyte layer is not particularly limited, and electrolyte layers used in known solid electrolytic capacitors may be applied. In this specification, the electrolyte layer may be read as a solid electrolyte layer, and the electrolytic capacitor may be read as a solid electrolytic capacitor. The electrolyte layer may be a laminate of two or more different electrolyte layers.

The electrolyte layer is arranged to cover at least part of the dielectric layer. The electrolyte layer may be formed using a manganese compound or a conductive polymer. Examples of conductive polymers include polypyrrole, polythiophene, polyaniline, derivatives thereof, and the like. These may be used independently and may be used in combination of multiple types. Also, the conductive polymer may be a copolymer of two or more monomers. A derivative of a conductive polymer means a polymer having a conductive polymer as a basic skeleton. For example, examples of derivatives of polythiophene include poly(3,4-ethylenedioxythiophene) and the like.

A dopant is preferably added to the conductive polymer. A dopant can be selected depending on the conductive polymer, and a known dopant may be used. Examples of dopants include naphthalenesulfonic acid, p-toluenesulfonic acid, polystyrenesulfonic acid, and salts thereof. An example electrolyte layer is formed using poly(3,4-ethylenedioxythiophene) (PEDOT) doped with polystyrene sulfonic acid (PSS).

The electrolyte layer containing the conductive polymer may be formed by polymerizing raw material monomers on the dielectric layer. Alternatively, it may be formed by applying a liquid containing a conductive polymer (and a dopant if necessary) to the dielectric layer and then drying it.

(Cathode extraction layer)
The cathode extraction layer is a conductive layer and is arranged to cover at least a portion of the electrolyte layer. The cathode extraction layer may include a carbon layer formed on the electrolyte layer and a metal paste layer formed on the carbon layer. The carbon layer may be formed of a conductive carbon material such as graphite and a resin. The metal paste layer may be formed of metal particles (for example, silver particles) and resin, and may be formed of a known silver paste, for example.

(Cathode lead terminal and anode lead terminal)
The cathode lead terminal includes a cathode terminal portion exposed at the bottom surface of the electrolytic capacitor and a connecting portion connected to the cathode terminal portion. The connecting portion is electrically connected to the cathode portion. For example, the connection may be connected to the cathode extraction layer by a conductive layer (eg, silver paste layer) or the like. The anode lead terminal includes an anode terminal portion exposed at the bottom surface of the electrolytic capacitor and a wire connection portion connected to the anode terminal portion. A wire connection is connected to the anode wire. A lead terminal may be formed by processing a metal sheet (including a metal plate and a metal foil) made of metal (copper, copper alloy, etc.) by a known metalworking method. The thickness of the lead terminal is not particularly limited, and may be in the range of 25 μm to 200 μm (for example, in the range of 25 μm to 100 μm).

The lead terminal may include a base material made of the metal described above and a plated layer formed on the base material. You may form a plating layer by a well-known method. The plated layer is made of metal (including alloys) such as nickel, gold, palladium, tin, and copper, and may include a nickel layer, a gold layer, a palladium layer, a tin layer, a copper layer, and the like. For example, plated layers may be laminated on the substrate in the order of a nickel layer, a gold layer, and a palladium layer.

(Exterior body)
The exterior body is arranged around the capacitor element so that the capacitor element is not exposed on the surface of the electrolytic capacitor. Furthermore, the exterior body is arranged so as to cover part of the anode lead frame and part of the cathode lead frame. The exterior body usually contains a resin (insulating resin) and an insulating filler.

The exterior body may be formed of a resin composition containing an insulating resin and an insulating filler (for example, an inorganic filler). The resin composition may contain a curing agent, a polymerization initiator, and/or a catalyst in addition to the insulating resin and insulating filler. Examples of insulating resins include epoxy resin, phenolic resin, urea resin, polyimide, polyamideimide, polyurethane, diallyl phthalate, unsaturated polyester, polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), and the like. The resin contained in the exterior body may be of one type, or may be of two or more types.

Examples of insulating fillers include insulating particles and insulating fibers. Examples of the insulating material that constitutes the insulating filler include insulating compounds (such as oxides) such as silica and alumina, glass, and mineral materials (such as talc, mica, and clay). The insulating filler contained in the exterior body may be of one type, or may be of two or more types.

An example of the manufacturing method (M) and the electrolytic capacitor (C) will be specifically described below with reference to the drawings. The configurations described above can be applied to the example methods described below. Also, the example methods described below may be modified based on the above description. Also, the matters described below may be applied to the above embodiments. Also, in the embodiments described below, components that are not essential to the manufacturing method and electrolytic capacitor of the present disclosure may be omitted. In order to facilitate understanding, the following figures may show shapes that are different from the actual shapes.

(Embodiment 1)
Embodiment 1 describes an example of a manufacturing method according to the present disclosure. In this manufacturing method, lead terminals 200 (anode lead terminal 210 and cathode lead terminal 220) are connected to capacitor element 110, as shown in FIG. Specifically, the end of anode lead terminal 210 is connected to anode portion 111 of capacitor element 110, and the cathode lead terminal 220 is connected to cathode portion 115 of capacitor element 110 (step (i)).

The anode lead terminal 210 is connected to the end of the anode wire 112 of the anode section 111 by welding or the like. Cathode lead terminal 220 is connected to cathode extraction layer 117 of cathode section 115 via conductive layer 141 . In addition, as shown in FIG. 2, the plurality of lead terminals 200 may be formed by processing (punching or bending) a portion of the metal sheet M. As shown in FIG. A plurality of capacitor elements 110 are arranged on each of the plurality of lead terminals 200 .

Capacitor element 110 includes anode portion 111 , dielectric layer 114 and cathode portion 115 . Anode section 111 includes anode body 113 and anode wire 112 . Anode body 113 is a rectangular parallelepiped porous sintered body, and dielectric layer 114 is formed on the surface thereof. A portion of anode wire 112 protrudes from one end face of anode body 113 toward front face 100f of electrolytic capacitor 100 (see FIG. 2). The other portion of anode wire 112 is embedded in anode body 113 .

The cathode section 115 includes an electrolyte layer 116 arranged to cover at least a portion of the dielectric layer 114 and a cathode extraction layer 117 formed on the electrolyte layer 116 . The cathode extraction layer 117 includes, for example, a carbon layer formed on the electrolyte layer 116 and a metal particle layer formed on the carbon layer. The metal particle layer is, for example, a metal paste layer (for example, silver paste layer) formed using a metal paste.

The anode lead terminal 210 includes an anode terminal portion 211 and a wire connection portion 212 . Anode terminal portion 211 is exposed at bottom surface 100b of electrolytic capacitor 100 (see FIG. 2). Wire connection 212 is connected to anode wire 112 . Cathode lead terminal 220 includes a cathode terminal portion 221 and a connection portion 222 . Cathode terminal portion 221 is exposed at bottom surface 100 b of electrolytic capacitor 100 . The connection portion 222 is electrically connected to the cathode extraction layer 117 (cathode portion 115 ) through the conductive layer 141 .

Next, the lead terminal 200 and the capacitor element 110 in the state shown in FIG. 1 are subjected to the plasma treatment described above. At this time, plasma processing is performed with the bottom surface 100b placed on the processing stage side of the plasma processing apparatus. As a result, the surface 200a of the lead terminal 200 other than the portion existing on the bottom surface 100b side is exposed to plasma and becomes a plasma-treated surface (plasma-treated surface 200b in FIG. 2). Specifically, the plasma-treated surface can be the surface that comes into contact with the exterior body in a later step. Also, in this case, the surface of the anode wire 112 can also be a plasma-treated surface. As a result, the adhesion between anode wire 112 and the outer package can also be improved.

When the lead terminal 200 is plasma-treated before connecting it to the capacitor element 110, first, only the lead terminal 200 is plasma-treated. When plasma-treating a metal sheet including a portion that will become a plurality of lead terminals, the plasma treatment may be performed after part of the metal sheet is processed into the shape of the lead terminal 200 (for example, the shape shown in FIG. 1). Plasma treatment may be performed before processing the . By performing plasma processing after processing into the shape of the lead terminal, the entire surface of the portion of the lead terminal 200 that comes into contact with the exterior body can be plasma-processed by one plasma processing. After the plasma treatment, the lead terminal 200 is connected to the capacitor element 110 as shown in FIG.

Next, as shown in FIG. 2, a portion of lead terminal 200 (a portion of anode lead terminal 210 and a portion of cathode lead terminal 220) and capacitor element 110 are covered with exterior body 150. Then, as shown in FIG. As a result, the plasma-treated surface 200 b of the lead terminal 200 is covered with the exterior body 150 . As a result, the effects described above can be obtained. After forming the exterior body 150, a plurality of electrolytic capacitors are individually separated as needed. Thus, an electrolytic capacitor is manufactured.

The present disclosure can be used for electrolytic capacitors and manufacturing methods thereof.

100: Electrolytic capacitor 110: Capacitor element 111: Anode part 115: Cathode part 141: Conductive layer 150: Exterior body 200: Lead terminal 200b: Plasma-treated surface 210: Anode lead terminal 220: Cathode lead terminal

Claims

A method of manufacturing an electrolytic capacitor including a capacitor element having an anode portion and a cathode portion, comprising:
step (i) of electrically connecting an anode lead terminal to the anode section and electrically connecting a cathode lead terminal to the cathode section;
a step (ii) of covering a portion of the anode lead terminal, a portion of the cathode lead terminal, and the capacitor element with an exterior body containing a resin in this order;
Prior to the step (ii), plasma treatment is applied to at least part of the metal surface of at least one lead terminal selected from the group consisting of the anode lead terminal and the cathode lead terminal to remove the at least part of the metal surface. further comprising a plasma treatment step with the plasma treated surface;
A method for manufacturing an electrolytic capacitor, wherein in the step (ii), at least a portion of the plasma-treated surface is covered with the exterior body.
The resin includes at least one selected from the group consisting of epoxy resins and phenolic resins,
2. The manufacturing method according to claim 1, wherein in said step (i), said plasma-treated surface is hydrophilized by said plasma treatment.
In the step (ii), the cathode lead terminal is connected to the cathode portion by a conductive layer containing metal particles and a resin containing at least one selected from the group consisting of epoxy resin, urethane resin, and phenol resin;
3. The method of claim 2, wherein a portion of said plasma treated surface contacts said conductive layer.
The manufacturing method according to any one of claims 1 to 3, wherein the step (ii) is performed within 72 hours after performing the plasma treatment step.
5. The metal surface comprises at least one selected from the group consisting of copper, gold, nickel, tin, lead, bismuth, silver, zinc, iron, chromium, and palladium. The manufacturing method described in .
The manufacturing method according to any one of claims 1 to 5, wherein the plasma treatment step is performed before the step (i).
Further comprising the step of roughening at least part of the surface of the lead terminal before the step (i) and before the plasma treatment step;
7. The manufacturing method according to claim 1, wherein in said plasma treatment step, said plasma treatment is applied to at least part of said roughened surface.
an electrolytic capacitor,
a capacitor element including an anode portion and a cathode portion;
a lead terminal including an anode lead terminal electrically connected to the anode section and a cathode lead terminal electrically connected to the cathode section;
an exterior covering a part of the lead terminal and the capacitor element and containing a resin,
The electrolytic capacitor, wherein at least part of the surfaces of the lead terminals that are in contact with the outer package are plasma-treated surfaces.
The resin includes at least one selected from the group consisting of epoxy resins and phenolic resins,
9. The electrolytic capacitor according to claim 8, wherein said plasma-treated surface has hydrophilic groups, and said resin is adsorbed to said plasma-treated surface via said hydrophilic groups.