JP2021097164A - Electrolytic capacitor and manufacturing method of the same - Google Patents

Abstract

To provide a manufacturing method of an electrolytic capacitor and an electrolytic capacitor in which an aluminum foil is less likely to wrinkle and an electrode body and an extraction terminal are less likely to break.SOLUTION: A manufacturing method of an electrolytic capacitor includes an annealing step of annealing an electrode body 1 between a laminating step of forming a carbon layer 3 on an aluminum foil 2 and pressing the carbon layer, and a connecting step of connecting the electrode body 1 and an extraction terminal 4 by pressure. That is, when the carbon layer 3 and the aluminum foil 2 are pressed, a hard aluminum foil 2 that has been work-hardened is used, and when the pressurization for connecting the electrode body 1 and the extraction terminal 4 is performed, the aluminum foil 2 that has been softened through the annealing step is used.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electrolytic capacitor and a method for manufacturing an electrolytic capacitor.

The electrolytic capacitor is configured by interposing an electrolyte between a pair of electrode bodies serving as an anode and a cathode. This electrolytic capacitor stores and discharges electric charges by capacitance. The electrolyte is an electrolyte, a solid electrolyte, a gel electrolyte, or a solid electrolyte or a gel electrolyte and an electrolyte.

The electrolytic capacitor can be regarded as a series capacitor in which capacitance is developed on the anode side and the cathode side. Therefore, the cathode side capacitance is also very important in order to efficiently utilize the anode side capacitance. The surface area of the cathode foil is also increased by etching, but there is a limit to the expansion of the surface area of the cathode foil from the viewpoint of the thickness of the cathode foil.

Therefore, an electrolytic capacitor in which a metal nitride film such as titanium nitride is formed on a cathode foil has been proposed (see Patent Document 1). In a nitrogen gas environment, titanium is evaporated by a vacuum arc vapor deposition method, which is a kind of ion plating method, and titanium nitride is deposited on the surface of the cathode foil. The metal nitride is inert, and it is difficult for a natural oxide film to be formed. In addition, the vapor-film film has fine irregularities and the surface area of the cathode is expanded.

Japanese Unexamined Patent Publication No. 4-61109

However, the process of vapor deposition of metal nitride is complicated and leads to high cost of electrolytic capacitors. Therefore, the inventors have considered forming a carbon layer on the aluminum foil on the cathode side. The cathode-side capacitance of this electrolytic capacitor is expressed by the storage action of the electric double layer formed on the interface between the polar electrode and the electrolyte. Electrolyte cations align at the interface with the carbon layer, pair with electrons in the carbon layer at very short distances, and form a potential barrier at the cathode.

The inventors considered that it was necessary to press the electrode body composed of the aluminum foil and the carbon layer in order to fix and adhere the carbon layer and the aluminum foil. Here, the extraction terminal is electrically and mechanically connected to the electrode body. The electrolytic capacitor is mounted on an electric circuit or an electronic circuit via an extraction terminal. As a method of connecting the electrode body and the extraction terminal, for example, stitch connection and cold pressure welding are known. Stitch connection and cold pressure welding involve pressurization during connection. That is, the electrode body undergoes at least two pressurizing steps, including press working of the carbon layer and the aluminum foil, and connection of the electrode body and the extraction terminal during the manufacturing process of the electrolytic capacitor.

When the carbon layer and the aluminum foil are pressed, if the aluminum foil is soft, the aluminum foil may be wrinkled. In the case of a winding type electrolytic capacitor, if the aluminum foil is wrinkled, it becomes difficult to wind the electrode body with high accuracy. Then, the area of the aluminum foil occupying the volume of the electrolytic capacitor is reduced, and the capacity of the electrolytic capacitor is reduced.

On the other hand, when the electrode body and the drawer terminal are connected, if the aluminum foil is hard, cracks may occur between the electrode body and the members of the drawer terminal. In the case of stitch connection, cracks may occur in the electrode body. When the crack reaches the connection point between the extraction terminal and the electrode body, the connection strength between the electrode body and the extraction terminal decreases. In the case of cold pressure welding, cracks may occur along the projected region of the pressing member, its surrounding region, and the peripheral edge. When a force for peeling the lead-out terminal and the electrode body is applied, the electrode body and the lead-out terminal are separated from each other at the crack as a base point, and the contact resistance becomes high.

Therefore, from the viewpoint of press working between the carbon layer and the aluminum foil, the aluminum foil is preferably a hard material represented by the tempering symbol of H. However, the hard aluminum foil tends to cause a problem in the connection between the electrode body and the extraction terminal. On the other hand, from the viewpoint of connecting the electrode body and the extraction terminal, for example, a soft aluminum foil represented by a tempering symbol of O is preferable. However, the soft aluminum foil is prone to wrinkles and reduces the capacity of the electrolytic capacitor.

As described above, the aluminum foil having a hardness suitable for one pressurizing step is not suitable for the other pressurizing step. The present invention has been proposed to solve the above problems, and an object of the present invention is to provide an electrolytic capacitor manufacturing method and an electrolytic capacitor in which wrinkles are less likely to occur in an aluminum foil and the electrode body and the extraction terminal are less likely to break. To do.

In order to solve the above problems, the method for manufacturing an electrolytic capacitor of the present invention is a method for manufacturing an electrolytic capacitor including a lead-out terminal, an electrode body to which the lead-out terminal is connected, and an electrolyte interposed between the electrode bodies. , A laminating step of forming a carbon layer contained in a carbon material on an aluminum foil and pressing it, an annealing step of forming the aluminum foil and the carbon layer, and annealing the electrode body which has undergone the laminating step, and a pressurizing step. It is characterized by having a connection step of connecting the electrode body and the extraction terminal that have undergone the annealing step.

In the laminating step, the carbon layer may be formed on the work-hardened aluminum foil.

In the annealing step, when the aluminum foil is pressed until the through cracks occur, the ratio of the pressing force to the depth of the depression when the through cracks occur in the aluminum foil becomes 6.5 or more and 15 N / mm or less. , The electrode body may be annealed.

In the annealing step, the electrode body may be heat-treated at 250 ° C. or higher.

The aluminum foil has an expanded surface region, and in the laminating step, the carbon material contained in the carbon layer may be inserted into the expanded surface region by the press.

In the laminating step, at least a part of the lead-out terminal and the electrode body may be metal-bonded by the pressurizing step.

The electrode body has an oxide film on the surface of the aluminum foil, leaving a metal substrate on which the oxide film has not been formed. In the laminating step, the carbon layer is formed on the oxide film, and in the connecting step, the carbon layer is formed on the oxide film. A crack may be formed in the oxide film by the pressurizing step, and the drawer terminal and the metal substrate may be brought into contact with each other through the crack.

In the connection step, the oxide film in contact with the drawer terminal may be crushed by the pressurization step.

In the electrode body, a surface expansion layer is formed on the surface of the aluminum foil, and the oxide film is formed on the surface layer of the surface expansion layer. The region in which the oxide film is not formed in the layer may be brought into contact with the extraction terminal.

In the connection step, the carbon layer may be pushed into the crack by the pressurizing step, and the drawer terminal and the metal base material may be brought into contact with each other through the carbon layer in the crack.

In the connection step, the electrode body and the extraction terminal may be stitch-connected.

In the connection step, the electrode body and the extraction terminal may be cold-pressed.

Further, in order to solve the above problems, the electrolytic capacitor of the present invention is an electrolytic capacitor including a lead-out terminal, an electrode body to which the lead-out terminal is connected, and an electrolyte interposed between the electrode bodies, and the electrode body. Has an aluminum foil having an enlarged surface region and a carbon material, and the carbon material enters the expanded surface region by press processing and has a carbon layer pressure-welded to the aluminum foil. It is characterized in that it is later annealed, and after anneading, it is pressure-connected to the lead-out terminal.

According to the present invention, wrinkles do not occur when the carbon layer and the aluminum foil are pressed, and cracks are unlikely to occur when the electrode body and the extraction terminal are connected.

It is sectional drawing of the electrode body of an electrolytic capacitor and a lead-out terminal. It is a flowchart which shows the manufacturing method of the electrode body of an electrolytic capacitor. It is a schematic diagram which shows the press in the laminating process. It is a schematic diagram which shows the connection process using a stitch connection, (a) shows the formation of a through hole, (b) shows the piercing of a stitch needle, and (c) shows a press. The relationship between the size of the through hole and the size inside the hole of the burr is shown, (a) is a back side view, (b) is an AA cross-sectional view, and (c) is a BB cross-sectional view. It is a schematic diagram which shows the connection process using cold pressure welding. It is a schematic diagram which shows the crack of the electrode body by a stitch connection. It is a schematic diagram which shows the crack of the electrode body by cold pressure welding. It is a schematic diagram which shows the example of the stitch connection structure of an electrode body and a drawer terminal. It is a schematic diagram which shows the example of the cold pressure welding structure of an electrode body and a drawer terminal.

The electrolytic capacitor and the manufacturing method according to the embodiment of the present invention will be described. The present invention is not limited to the embodiments described below.

(Outline of manufacturing method)
The electrolytic capacitor has electrode bodies on the anode side and the cathode side, and an electrolyte is interposed between these electrode bodies. As the electrolyte, a solid electrolyte layer such as an electrolytic solution or a conductive polymer, a gel electrolyte, or a solid electrolyte layer in which an electrolytic solution is used in combination with the gel electrolyte is used. This electrolytic capacitor is provided with an electrode on which a dielectric oxide film layer is formed on the anode side, and a polarizable electrode having an electric double layer capacitance on the cathode side. As shown in FIG. 1, the electrode body 1 on the cathode side, which is a polarizable electrode, is formed by laminating a carbon layer 3 on an aluminum foil 2.

A drawer terminal 4 is connected to the electrode body 1. The electrolytic capacitor is mounted on an external electronic circuit or electric circuit via the extraction terminal 4. The lead-out terminal 4 is composed of an aluminum wire 4a and a metal wire 4b, and the aluminum wire 4a and the metal wire 4b are connected by arc welding or the like. The aluminum wire 4a includes a substantially cylindrical round bar portion 43 and a flat plate portion 41 formed by pressing the round bar portion 43, and the round bar portion 43 has a flat plate portion 41 on the flat plate portion 41 side. An inclined portion 44 whose thickness is linearly reduced to the thickness of the flat plate portion 41 is formed. The metal wire 4b is connected to the electrode body 1 via the flat plate portion 41, and the metal wire 4b is drawn out to the outside of the electrolytic capacitor. Not limited to this, the drawer terminal 4 may be provided with a flat plate portion 41, and may have a tab shape as a whole.

That is, the method for manufacturing the electrolytic capacitor includes a step of manufacturing the electrode body 1 and a step of connecting the electrode body 1 and the extraction terminal 4. As shown in FIG. 2, the electrode body 1 is manufactured through a laminating step of laminating the carbon layer 3 on one or both sides of the aluminum foil 2 (step S01). Further, the electrode body 1 goes through a connection step in which the extraction terminal 4 is connected (step S03). Both the laminating process and the connecting process include a pressing process. Then, in this manufacturing method, annealing is performed by annealing the electrode body 1 between the step of laminating the aluminum foil 2 and the carbon layer 3 (step S01) and the step of connecting the electrode body 1 and the extraction terminal 4 (step S03). A process is added (step S02).

(Laminating process)
The carbon layer 3 is laminated on the work-hardened aluminum foil 2. For example, as the aluminum foil 2, a hard material in which the basic symbol of the tempering symbol defined by JIS standard H0001 is H is used. The aluminum foil 2 represented by the tempering symbol starting with H does not wrinkle even when pressed during the laminating step of step S01.

It is desirable that the surface of the aluminum foil 2 is enlarged. The surface expansion is a process using electrolytic etching, chemical etching, sandblasting, or the like, or a process of vapor deposition or sintering of metal particles or the like on the aluminum foil 2. Examples of electrolytic etching include AC etching. In the AC etching process, the cathode foil is immersed in an acidic aqueous solution containing halogen ions such as hydrochloric acid, and an AC current is applied. In chemical etching, the metal foil is immersed in an acid solution or an alkaline solution. That is, the expanded surface region of the aluminum foil 2 has a spongy etching pit or a porous structure composed of voids between dense powders. The etching pit may be a tunnel-shaped pit formed by direct current etching, or the tunnel-shaped pit may be formed so as to penetrate the cathode foil.

An oxide film may be intentionally or naturally formed in the widened area. The natural oxide film is formed by the reaction of the cathode foil with oxygen in the air, and the chemical conversion film is intentionally applied by a chemical conversion treatment in which a voltage is applied in a solution in the absence of halogen ions such as an aqueous solution of adipic acid or boric acid. It is an oxide film formed. The oxide film produced by this method is aluminum oxide formed by oxidizing the expanded region of the aluminum foil 2.

The carbon layer 3 included in the electrode body 1 contains a carbon material as a main material. Examples of carbon materials include natural plant tissues such as palm shavings, synthetic resins such as phenol, activated carbon derived from fossil fuels such as coal, coke, and pitch, Ketjen Black (hereinafter, KB), and acetylene black. Examples thereof include carbon black such as channel black, carbon nanohorns, amorphous carbon, natural graphite, artificial graphite, fossilized Ketjen black, and mesoporous carbon. Further, examples of the carbon material include fibrous carbon such as carbon nanotubes (hereinafter, CNT) and carbon nanofibers (hereinafter, CNF).

The carbon material contained in the carbon layer 3 is preferably carbon black, which is spherical carbon. When the enlarged surface region formed on the surface of the aluminum foil 2 has an etching pit, by using carbon black having a particle size smaller than the opening diameter of the etching pit, it is easy to penetrate deeper into the etching pit, and the carbon layer 3 is made of aluminum. Adheres to the foil 2.

Further, the carbon material contained in the carbon layer 3 may be a mixture of scaly or scaly graphite and carbon black which is spherical carbon. The scaly or scaly graphite preferably has an aspect ratio of a minor axis to a major axis in the range of 1: 5 to 1: 100. Carbon black, which is a spherical carbon, preferably has a primary particle size of 100 nm or less on average. When the carbon layer 3 containing the carbon material of this combination is laminated on the aluminum foil 2, the carbon black is easily rubbed into the pores of the expansion layer by graphite. Graphite is easily deformed along the uneven surface of the enlarged surface region, and is easily stacked on the uneven surface. Then, the graphite acts as a pressing lid and holds down the spherical carbon rubbed into the pores. Therefore, the adhesion and fixability between the carbon layer 3 and the aluminum foil 2 are further enhanced.

The carbon layer 3 is laminated on the aluminum foil 2 by forming a slurry, applying it to the aluminum foil 2, and drying it. After the slurry is dried, the carbon layer 3 and the aluminum foil 2 are pressed against each other by press working. Alternatively, these carbon layers 3 are laminated on the aluminum foil 2 by molding them into a sheet shape and placing them on the aluminum foil 2. After placing the sheet, the sheet-shaped carbon layer 3 and the aluminum foil 2 are pressure-welded by press working.

The slurry is prepared by dispersing the carbon material contained in the carbon layer 3 in a dispersion solvent and adding a binder if necessary. The produced slurry is applied to the aluminum foil 2 by a slurry casting method, a doctor blade method, a spray spray method, or the like. After applying the slurry to the aluminum foil 2, the solvent is volatilized by drying. The papermaking molding sheet is produced by dispersing the carbon material contained in the carbon layer 3 in a dispersion solvent, adding a binder if necessary, filtering under reduced pressure and drying, and then peeling the deposit from the filter paper. The produced papermaking molded sheet is rolled under press pressure and then crimped onto the aluminum foil 2.

In the preparation of slurry and papermaking sheet, the dispersion solution is methanol, alcohol such as ethanol or 2-propanol, hydrocarbon solvent, aromatic solvent, N-methyl-2-pyrrolidone (NMP) or N, N-dimethyl. An amide-based solvent such as formamide (DMF), water, and a mixture thereof. As the dispersion method, a mixer, jet mixing (jet collision), ultracentrifugation treatment, or other ultrasonic treatment is used. Examples of the binder include styrene-butadiene rubber (SBR), fluorine-based, polyimide-based, polyvinyl alcohol, and the like. As the filter paper of the papermaking molded sheet, a non-woven fabric made of glass fiber, an organic non-woven fabric (polytetrafluoroethylene, polyethylene, etc.), or a non-woven fabric made of metal fiber is used.

As shown in FIG. 3, the carbon layer 3 and the aluminum foil 2 are press-processed after the carbon layers 3 are laminated. For example, in press working, an electrode body 1 composed of a carbon layer 3 and an aluminum foil 2 is sandwiched between press rollers 100, and press linear pressure is applied. The press pressure is preferably about 0.01 to 100 t / cm ^2. The press working improves the adhesion between the carbon layer 3 and the aluminum foil 2, reduces the fixability of the carbon layer 3 and the interfacial resistance between the carbon layer 3 and the aluminum foil 2.

Since the aluminum foil 2 is a hard material whose basic symbol of the tempering symbol is H, wrinkles are less likely to occur even with this press line pressure. Therefore, the adhesion between the carbon layer 3 and the aluminum foil 2 can be more ensured by the high press line pressure. In particular, when the surface expansion region is formed, the carbon layer 3 can be pushed into the surface expansion region. Therefore, even if the expanded surface region reaches the deep region of the aluminum foil 2 and the expanded surface region is complicated, the aluminum foil 2 and the carbon layer 3 can be brought into close contact with each other without a gap.

When the binder is added to the carbon layer 3, the press roller 100 to which heat equal to or higher than the softening temperature of the binder is applied may be used. By doing so, the fluidity of the carbon layer 3 is increased, and the carbon material can more easily enter the widened area. However, if the amount of the binder added is reduced by 10 wt% or more, the adhesion of the carbon material is lowered. Therefore, when the binder is styrene-butadiene rubber or fluorine-based, the heating temperature is preferably 350 ° C. or lower, and the amount of decrease in the binder is within 10 wt% or less. When the binder is a polyimide type, the heating temperature is preferably 500 ° C. or lower, and the amount of reduction of the binder is within 10 wt% or less.

(Annealing process)
After the carbon layer 3 is formed on the work-hardened aluminum foil 2 and pressed, the electrode body 1 is first moved to the annealing step for the connection step involving pressurization. This annealing step softens the work-hardened aluminum foil 2. In this annealing step, the electrode body 1 is exposed to a temperature environment of 250 ° C. or higher and 500 ° C. or lower. Preferably, in the annealing step, the electrode body 1 is exposed to a temperature environment of 250 ° C. or higher and 350 ° C. or lower.

When the heating temperature is 250 ° C. or higher, the work-hardened aluminum foil 2 softens to the same level as or higher than the aluminum foil 2 having the tempering symbol O defined in JIS standard H0001. If the temperature is lower than 250 ° C., when stitch connection is selected in the connection step, it is difficult to apply a large pressing force for surface contact between the drawer terminal 4 and the core portion of the aluminum foil 2. If the maximum heating temperature exceeds 350 ° C., there is a high possibility that the stretchability of the aluminum foil will be significantly reduced due to the generation of hydrogen blister. However, by setting the dew point temperature to 5 ° C. or lower in a low humidity environment under the heating atmosphere, the brittleness of the aluminum foil 2 can be suppressed even when the heating temperature is 350 ° C. or higher.

The heating time is not particularly limited. For example, if the heating time is 30 minutes or more, the aluminum foil 2 represented by the tempering symbol O can be softened to the same level or higher. The heating atmosphere is not particularly limited, and may be an air atmosphere or an inert atmosphere. Preferably, the electrode body 1 is heated in an inert atmosphere. Under an inert atmosphere, it is not necessary to control the oxidation of the aluminum foil 2 and the carbon layer 3. The inert atmosphere is an atmosphere in which the amount of the reactive gas is low and the atmosphere is filled with the inert gas or the neutral gas. The reactive gas is oxygen, water vapor, carbon gas or the like. The inert gas is argon, helium, or the like. The neutral gas is nitrogen, ammonia or the like.

In the annealing step, it is preferable to soften the hardness value of the aluminum foil 2 of the electrode body 1 to 6.5 or more and 15 N / mm or less. The value of the hardness of the aluminum foil 2 is the ratio of the pressing force to the depth of the recess when the aluminum foil 2 is pressed until the through cracks occur and the aluminum foil 2 has the through cracks. If it is less than 6.5 N / mm, the electrode body 1 may be stretched or wrinkled in the manufacturing process due to excessive softening. On the other hand, if it exceeds 15 N / mm, the connection strength between the extraction terminal 4 and the electrode body 1 is lowered due to the hardness.

This hardness value is determined in accordance with the measuring method specified in JIS standard Z2247 or ISO20482: 2003. That is, at a test temperature of 10 or more and 35 ° C. or less, a wrinkle retainer having a hole having a diameter of 27 mm and a die having a hole having a diameter of 33 mm are placed so that the holes overlap, and the aluminum foil 2 is placed at 10 kN between them. Tighten with the tightening load of, and push a spherical punch into the aluminum foil 2. The spherical punch has a spherical surface with a diameter of 20 mm. The pushing speed of the punch shall be 5 or more and 10 mm / min or less. A dent is formed in the aluminum foil 2 until a through crack occurs. Then, the depth of the dent and the pressing force when the through crack occurs are obtained, and the value of the hardness is obtained.

(Connection process)
As shown in FIGS. 4 and 5, after the aluminum foil 2 is softened in the annealing step, the process proceeds to the connecting step between the drawer terminal 4 and the electrode body 1. In the connection step between the extraction terminal 4 and the electrode body 1, a connection method involving pressurization such as stitch connection or cold pressure welding is used. Both connection methods are connected to the electrode body 1 by superimposing the flat plate portion 41 on the electrode body 1 and applying pressure.

As shown in FIG. 4A, in the stitch connection, first, a through hole 11 is provided in advance in the electrode body 1. For example, the electrode body 1 is placed on a die having a punched hole, and the drilling member is passed through the die. The through hole 11 is, for example, a square hole. After the through hole 11 is formed, the flat plate portion 41 is overlapped with the electrode body 1 so as to cover the through hole 11 with the flat plate portion 41 of the extraction terminal 4.

As shown in FIG. 4B, a stitch needle 200 having a quadrangular pyramid shape is coaxially arranged with the through hole 11 toward the tip, and is lowered along the axis from directly above the flat plate portion 41 of the drawer terminal 4. It breaks through the flat plate portion 41 of the drawer terminal 4. The region of the flat plate portion 41 that covers the through hole 11 is pushed into the through hole 11 by the stitch needle 200 and stretched, and is pierced at the breaking point. Therefore, a burr 42 is generated on the pull-out side of the stitch needle 200 on the flat plate portion 41 of the drawer terminal 4. The burr 42 projects to the back surface of the electrode body 1 through the through hole 11.

Here, as shown in FIG. 5, the dimension of the through hole 11 formed in advance is H, and the inside dimension of the burr 42 of the extraction terminal 4 as seen from the direction orthogonal to the width of the through hole 11 is X. To do. The hole dimension X is the range covered by the burr 42 whose position in the through hole 11 is measured. The range covered by the burr 42 is the length from one end to the other end of the burr 42 with the center of the through hole 11 in between. At this time, the burr 42 is formed so that the relationship between the through hole 11 and the burr 42 is H> X. This method is called "drilling (through hole> burr) stitch connection" including the point where the through hole 11 is formed in advance. For "drilling (through hole> burr) stitch connection", a stitch needle 200 thinner than the through hole 11 is used in consideration of the thickness and stretchability of the flat plate portion 41 of the drawer terminal 4.

In the "drilling (through hole> burr) stitch connection", the inner peripheral surface of the through hole 11 formed in advance and the outer peripheral surface of the burr 42 of the drawer terminal 4 are not in contact with each other over the entire circumference. Then, the peripheral region of the through hole 11 of the electrode body 1 is not exposed to the exit side of the stitch needle 200 by the stitch needle 200. Therefore, the electrode body 1 is not cut up, the peripheral region of the through hole 11 of the electrode body 1 is kept flat, and only the burr 42 of the extraction terminal 4 stands on the back surface side of the electrode body 1.

Returning to FIG. 4, as shown in FIG. 4C, the mold is pressed from the back side of the electrode body 1 and pressed. Typically, in press working, the press die is brought into contact with the flat plate portion 41 of the drawer terminal 4. Then, the press lower die is brought closer to the back side of the electrode body 1. At this time, in the "drilling (through hole> burr) stitch connection", the burr 42 of the drawer terminal 4 exposed on the back surface side of the electrode body 1 is folded back by press working, and the burr of the drawer terminal 4 is folded back on the back surface side of the electrode body 1. 42 is pressed. Then, the single electrode body 1 is sandwiched between the flat plate portion 41 of the extraction terminal 4 and the burr 42.

Further, in the stitch connection, the stitch needle 200 thicker than the through hole 11 may be used. A method using a stitch needle 200 thicker than the through hole 11 is called "drilling (through hole <burr) stitch connection". In this stitch connection, the relationship between the pre-formed through hole 11 and the burr 42 is H <X. Therefore, the peripheral region of the through hole 11 of the electrode body 1 is exposed to the back side of the electrode body 1 by the stitch needle 200, and the electrode body 1 is cut up around the through hole 11. Then, the burr 42 of the extraction terminal 4 and the cut-up portion (not shown) of the electrode body 1 stand on the back surface side of the electrode body 1.

Further, the electrode body 1 and the flat plate portion 41 of the extraction terminal 4 may be pierced together by the stitch needle 200 without forming the through hole 11 in the electrode body 1. A stitch connection in which the through hole 11 is not formed in advance is called a “holeless stitch connection”. In a state where the through hole 11 is not formed, the flat plate portion 41 and the electrode body 1 are overlapped and pierced by the stitch needle 200. Then, the burr 42 generated from the flat plate portion 41 of the extraction terminal 4 and the cut-up portion of the electrode body 1 stand on the back surface side of the electrode body 1.

In "drilling (through hole <burr) stitch connection" and "holeless stitch connection", the burr 42 of the drawer terminal 4 exposed on the back side of the electrode body 1 and the cut-out portion of the electrode body 1 are folded back by press working. In this press working, the burr 42 is pressed against the double electrode body 1, and the double electrode body 1 is sandwiched between the flat plate portion 41 of the extraction terminal 4 and the burr 42.

The aluminum foil 2 is softened by the annealing process. Therefore, regardless of the stitch connection method, the aluminum foil 2 is appropriately stretched by a press and adheres to the burr 42 of the drawer terminal 4, and the connection strength is improved.

Next, as shown in FIG. 6, in the cold pressure welding, the electrode body 1 and the flat plate portion 41 of the drawer terminal 4 are pressed by the pressing body 300 in the stacking direction in a non-heated state. As a result, in the cold pressure welding, the electrode body 1 and the flat plate portion 41 of the extraction terminal 4 are pressure-welded.

In cold pressure welding, the flat plate portion 41 of the drawer terminal 4 is restrained from one flat surface and both side surfaces so that the one flat surface and both side surfaces cannot be deformed and are immovable in position. Then, the electrode body 1 is superposed on the flat plate portion 41. The pressing member 300 is lowered from the electrode body 1 side, and the pressing member 300 presses the laminated body of the electrode body 1 and the flat plate portion 41. The pressing member 300 preferably has a trapezoidal tip, which reduces shear stress around the pressing member and facilitates fluid deformation of the aluminum foil 2.

The aluminum foil 2 that has undergone the annealing step is highly stretchable. Therefore, in the process of forming the recess in the drawer terminal 4 by the pressing member 300, the electrode body 1 between the pressing member 300 and the drawer terminal 4 easily flows the aluminum foil 2 following the recess of the drawer terminal 4. Deform. Then, the electrode body 1 is deformed along the concave portion of the extraction terminal 4, and the electrode body 1 and the extraction terminal 4 are brought into close contact with each other without a gap.

(Action effect)
Here, as shown in FIG. 7, in the stitch connection, the edge of the aluminum foil 2 is fluidly deformed in the band longitudinal direction due to the rolling force that spreads radially around the burr 42. Therefore, if the aluminum foil 2 has not undergone the annealing step, cracks 5 in the shape of ear cracks are generated in the aluminum foil 2 due to poor stretchability. That is, a crack 5 extending from the outer edge of the aluminum foil 2 toward the center of the foil is generated. If the crack 5 extends to the stitch connection portion, it is not possible to secure a sufficient connection state between the electrode body 1 and the extraction terminal 4, and the connection strength is lowered.

Further, as shown in FIG. 8, in the cold pressure welding, when the annealing step is not performed, the electrode body 1 has a projection region 1a of the pressing member 300 on the electrode body 1 due to the poor stretchability of the aluminum foil 2. A large shear stress is generated at the boundary with the surrounding region 1b. Only the projection region 1a of the pressing member 300 sinks into the recess of the flat plate portion 41 of the extraction terminal 4, and a crack 5 is generated between the projection region 1a and the peripheral region 1b. Therefore, when the electrode body 1 is not subjected to the annealing step, the electrode body 1 is in close contact only with the bottom surface of the recess formed in the extraction terminal 4, and cracks 5 are formed around the electrode body 1, the contact resistance is increased, and the connection strength is decreased.

However, in this method for manufacturing an electrolytic capacitor, the electrode body 1 is formed between a laminating step of forming a carbon layer 3 on an aluminum foil 2 and pressing it, and a connecting step of connecting the electrode body 1 and the extraction terminal 4 by pressurization. Was annealed through an annealing process. That is, when the carbon layer 3 and the aluminum foil 2 are pressed, the hard aluminum foil 2 that has been work-hardened is used, and when the pressurization for connecting the electrode body 1 and the drawer terminal 4 is performed, an annealing step is performed. The softened aluminum foil 2 was used.

As a result, wrinkles do not occur in the aluminum foil 2 in the laminating process, and cracks 5 do not occur between the connecting members such as the electrode body 1 and the drawer terminal 4 in the connecting process. Therefore, the laminating process does not cause a decrease in connection strength and an increase in contact resistance, and the connection process does not cause a decrease in connection strength and an increase in contact resistance.

In the annealing step, the electrode body 1 was heat-treated at 250 ° C. or higher. As a result, the aluminum foil 2 can be softened to the same level as the aluminum foil 2 whose tempering symbol is indicated by O, and the electrode body 1 and the extraction terminal 4 can be satisfactorily connected in the connection step.

Further, the aluminum foil 2 has an enlarged surface region, and the carbon layer 3 is a carbon layer containing a carbon material. In the press in the laminating process, the pressing force is increased without causing wrinkles in the aluminum foil 2. The carbon material was allowed to enter the widened area. As a result, the aluminum foil 2 and the carbon layer 3 are in close contact with each other without a gap, the connection strength between the aluminum foil 2 and the carbon layer 3 is further improved, and the contact resistance is further reduced.

(Modified example of the embodiment)
With this electrolytic capacitor, it is difficult to cause cracks 5 in the aluminum foil 2 in the connection process. Therefore, the pressing force during the connection process including stitch connection or cold pressure welding may be adjusted to create a connection structure between the electrode body 1 and the extraction terminal 4 as shown in FIGS. 9 and 10.

That is, the metal base 24 of the aluminum foil 2 is stretched to the extent that the oxide film layer 23 formed of the oxide film cannot follow. The metal base 24 refers to a region of the aluminum foil 2 excluding the oxide film layer 23, that is, a region having conductivity due to non-oxidation and being more stretchable than the oxide film 23. The oxide film layer 23 cannot follow the stretching of the metal base 24 due to its low stretchability and fragility, and causes wrinkle-like cracks in the contact region between the extraction terminal 4 and the electrode body 1. The metal base 24 is exposed from the cracks in the oxide film layer 23. The drawer terminal 4 pressed against the electrode body 1 comes into contact with the metal base 24 of the aluminum foil 2 through the cracks in the oxide film layer 23. Therefore, the contact resistance between the electrode body 1 and the extraction terminal 5 is reduced.

When the surface expansion layer 25 is formed on the aluminum foil 2 by being formed by the surface expansion region, the region where the oxide film layer 23 of the surface expansion layer 25 is not formed is exposed from some cracks. In the drawer terminal 4, the oxide film layer 23 of the expansion layer 25 comes into contact with the unformed region through the crack. Further, even when the surface expansion layer 25 is formed on the aluminum foil 2, some cracks also divide the surface expansion layer 25 in which the oxide film layer 23 is not formed, and the core portion 22 is formed from the cracks. Be exposed. The core portion 22 is the remaining portion of the aluminum foil 2 excluding the surface expansion layer 25. The drawer terminal 4 comes into contact with the core portion 22 through this crack.

Further, by pressing the electrode body 1 and the extraction terminal 4 against each other, the brittle oxide film layer 23 can be crushed, the extraction terminal 4 and the metal base 24 can be brought close to each other, and the crack can be widened. Thereby, the contact area between the drawer terminal 4 and the metal base 24 can be increased. When the graphite contained in the carbon layer 3 is scaly or flaky, the oxide film layer 23 can be easily crushed, the distance between the drawer terminal 4 and the metal base 24 can be further shortened, and the cracks can be further opened. ..

Further, the pressing force can be increased to metal-bond at least a part of the portion where the extraction terminal 4 and the metal base 24 are in contact with each other. By the metal bonding, the connection strength between the extraction terminal 4 and the electrode body 1 can be further increased, the interface resistance between the extraction terminal 4 and the electrode body 1 is lowered, and the contact resistance is improved.

Further, the carbon layer 3 can be pushed into the crack formed in the oxide film layer 23 by the pressurization during the connection step, and the outlet terminal 4 and the metal base 24 can be electrically connected through the carbon layer 3 in the crack. .. In this case, it is preferable that the carbon layer 3 is mixed with carbon black, which is a spherical carbon. Carbon black, which is a spherical carbon, preferably has a primary particle size of 100 nm or less on average. Carbon black is easily rubbed into the cracks of the oxide film layer 23 by graphite. Graphite is easily deformed along the uneven surface of the expansion layer 25 and is easily stacked on the uneven surface. Then, the graphite acts as a pressing lid and holds down the spherical carbon rubbed into the crack. Therefore, the electrical connection between the drawer terminal 4 and the metal base 24 is made more reliable.

As shown in FIG. 9, in the stitch connection, the burr 42 presses the electrode body 1 toward the flat plate portion 41 by press working, and the electrode body 1 is in pressure contact with the flat plate portion 41 of the extraction terminal 4. The electrode body 1 which has lost its place due to pressure contact with the flat plate portion 41 is also pressure contacted with the burr 42. Therefore, the extraction terminal 4 is electrically connected to the electrode body 1 when the flat plate portion 41 comes into contact with the metal base 24 through the crack, or in addition, the burr 42 comes into contact with the metal base 24 through the crack.

Further, as shown in FIG. 10, in the cold pressure welding, the electrode body 1 is pressed from the bottom surface and the side surface of the recess of the extraction terminal 4, and faces the bottom surface of the extraction terminal 4 and the side surface of the extraction terminal 4. A crack is generated in the place where it is used. The flat plate portion 41 comes into contact with the metal base 24 through these cracks and is electrically connected to the electrode body 1.

(Example)
Hereinafter, the present invention will be described in more detail based on Examples. The present invention is not limited to the following examples.

(Example 1)
The sample of Example 1 was prepared as follows. The sample is a stitch-connected lead-out terminal 4 and an electrode body 1, and an electrolytic capacitor having an electrode body 1 having a carbon layer 3 on the cathode side is assumed.

In the sample of Example 1, the aluminum foil 2 which was work-hardened and whose basic symbol of the tempering symbol is indicated by H was used. The aluminum foil 2 had a foil thickness of 30 μm and was etched to increase the surface area by 22 times. As a result, the aluminum foil 2 had a depth of 5.5 μm per side, a total of 11 μm on both sides, and a thickness of 19 μm at the core. The depth of the widened area is the average of the depths from the surface of the aluminum foil 2 to the deepest part of the etching pit. The thickness of the core is the average of the thickness of the layer that the etching pit does not reach. Further, the aluminum foil 2 was subjected to chemical conversion treatment to form an oxide film in the expanded surface region. In the chemical conversion treatment, a voltage was applied in an aqueous solution of ammonium dihydrogen phosphate. As a result, the nominal chemical conversion voltage of the oxide film was 1.2 Vfs.

In Example 1, the carbon layer 3 containing graphite and carbon black was laminated. The ratio of graphite to carbon black was 75:25. Specifically, graphite and carbon black were added to 75 ml of pure water adjusted to pH 8 with ammonia at a mass ratio of 75:25, and dispersed by a stirrer. When the carbon material was added, styrene-butadiene rubber was also added as a binder at the same time. The resulting slurry was applied to the aluminum foil 2 and dried at 100 ° C.

In the press working in the laminating step, a press line pressure was applied to the aluminum foil 2 coated with the carbon layer 3. The press line pressure was 5.38 kNcm ^-1 . The press line pressure was applied using a press machine manufactured by Takumi Giken Co., Ltd. The diameter of the press roller was 180 mm, the press processing width was 130 mm, and the aluminum foil 2 was conveyed once at 3 m / min.

After the press working in the laminating step was completed, the process was started in the annealing step of the electrode body 1 of Example 1. In the annealing step with respect to Example 1, the electrode body 1 was exposed to 300 ° C. and an air atmosphere for 2 hours. After passing through this annealing step, the hardness of the electrode body 1 of Example 1 was measured using the measuring method specified in JIS standard Z2247. As a result, the hardness of the electrode body 1 of Example 1 was 6.8 N / mm. Met. The hardness of the aluminum foil of the basic symbol H of the tempering symbol and the aluminum foil of the tempering symbol O was also measured and found to be 12 N / mm and 18 N / mm, respectively.

After the annealing step was completed, the process moved to the step of connecting the electrode body 1 and the extraction terminal 4 of Example 1. The drawer terminal 4 is composed of an aluminum wire 4a and a metal wire 4b, and the round bar portion 43 of the aluminum wire 4a is pressed or the like to form a flat plate portion 41.

In the connection step of Example 1, "stitch connection without holes" was performed. That is, the stitch needle 200 was pierced through the electrode body 1 and the flat plate portion 41 of the extraction terminal 4 without penetrating the through hole 11. Then, by applying a vertical press, the burr 42 of the extraction terminal 4 is pressed against the duplicated electrode body 1, and the duplicated electrode body 1 is sandwiched between the flat plate portion 41 of the extraction terminal 4 and the burr 42. It was. The pressure of the vertical press was 120 N.

Corresponding to the sample of Example 1, a sample of Comparative Example 1 was prepared in which only the presence or absence of the annealing step was different. In Comparative Example 1, an aluminum foil 2 that was work-hardened and whose basic symbol of the tempering symbol is indicated by H was used. In Comparative Example 1, the enlarged surface region and the oxide film were formed under the same conditions, and the laminating step including the press and the connecting step of "stitch connection without holes" were executed under the same conditions. However, in Comparative Example 1, the annealing step between the laminating step and the connecting step was omitted. Therefore, at the time of the connection step, the aluminum foil 2 of Comparative Example 1 remained a hard material in which the basic symbol of the work-hardened tempering symbol was represented by H.

Since the aluminum foil 2 at the time of the laminating step is a hard material that has been processed and hardened, wrinkles did not occur in the aluminum foil 2 provided in the samples of Example 1 and Comparative Example 1. Next, the samples of Example 1 and Comparative Example 1 were visually observed to examine the cracked state of the electrode body 1. Ten samples of Example 1 and Comparative Example 1 were prepared, and the number of samples without cracks 5, the number of samples with cracks 5 but not reaching the stitch connection, and the number of cracks 5 were found. The number of samples reaching the stitch connection was counted.

The count results are shown in Table 1 below. In Table 1 below, item A is the number of samples without cracks 5, item B is the number of samples with cracks 5 but not reaching the stitch connection, and item C is. The number of samples in which the crack 5 reaches the stitch connection.
(Table 1)

As shown in Table 1, none of the samples of Example 1 had cracks 5 reaching the stitch connection. On the other hand, in Comparative Example 1, 9 out of 10 samples had cracks 5 reaching the stitch connection. When the work-hardened aluminum foil 2 is used and the annealing process is added before the connection process, the aluminum foil 2 does not wrinkle in the press of the lamination process, and the electrode body 1 is seriously affected by the press in the connection process. It was confirmed that crack 5 did not occur.

(Examples 2 and 3)
A sample of Example 2 was prepared. The sample of Example 2 is different from that of Example 1 in that the laminating step is performed using the work-hardened aluminum foil 2 and the bonding step proceeds through the annealing step, and the laminating step and the connecting step include press working. Common. The sample of Example 2 differs only in the type of stitch connection from that of Example 1. For the sample of Example 2, the connection step was executed by "drilling (through hole> burr) stitch connection".

In the second embodiment, the through hole 11 was formed in advance in the electrode body 1, and the stitch needle 200 was pierced through the flat plate portion 41 of the extraction terminal 4 so as to pass through the through hole 11. Only the burr 42 of the extraction terminal 4 stood up on the back surface side of the electrode body 1. A vertical press was applied, and the burr 42 of the drawer terminal 4 was folded back. As a result, the burr 42 of the extraction terminal 4 was pressed against the electrode body 1 which remained single.

Corresponding to the sample of Example 2, a sample of Comparative Example 2 was also prepared, which differs from Example 2 only in that the annealing step was omitted.

Moreover, the sample of Example 3 was prepared. The sample of Example 3 is a point where a laminating process is performed using a work-hardened aluminum foil 2 and the process proceeds to a connecting process through an annealing process, a point where the laminating process and the connecting process include press working, and a type of stitch connection. In common with Example 1. In the sample of Example 3, the carbon layer 3 laminated on the aluminum foil 2 is different from that of Example 1.

In the sample of Example 3, a carbon layer containing only carbon black as a carbon material was laminated on the aluminum foil 2. Specifically, carbon black was added to 75 ml of pure water adjusted to pH 8 with ammonia and dispersed by a stirrer. When the carbon material was added, styrene-butadiene rubber was also added as a binder at the same time. The resulting slurry was applied to the aluminum foil 2 and dried at 100 ° C. Subsequent press working conditions are the same as in Example 1.

Corresponding to the sample of Example 3, a sample of Comparative Example 3 was also prepared, which differs from Example 3 only in that the annealing step was omitted.

Since the aluminum foil 2 in the laminating step is a hard material that has been processed and hardened, wrinkles did not occur in the aluminum foil 2 included in the samples of Examples 2 and 3 and Comparative Examples 2 and 3. Next, the samples of Examples 2 and 3 and Comparative Examples 2 and 3 were visually observed to examine the cracked state of the electrode body. Prepare 10 samples for each sample, the number of samples without cracks 5, the number of samples with cracks 5 but not at the stitch connection, and the cracks 5 have reached the stitch connection. The number of samples was counted.

The count results are shown in Table 2 below. In Table 1 below, item A is the number of samples without cracks 5, item B is the number of samples with cracks 5 but not reaching the stitch connection, and item C is. The number of samples in which the crack 5 reaches the stitch connection.
(Table 2)

As shown in Table 2, none of the samples of Example 2 had cracks 5 reaching the stitch connection. On the other hand, in Comparative Example 2, 7 out of 10 samples had cracks 5 reaching the stitch connection portion. As a result, if the work-hardened aluminum foil 2 is used regardless of the type of stitch connection and the annealing process is added before the connection process, the aluminum foil 2 does not wrinkle in the press of the lamination process and the press of the connection process. It was confirmed that no serious crack 5 was generated in the electrode body 1.

Further, in Example 3, cracks 5 reaching the stitch connection portion were generated in 2 out of 10 samples. On the other hand, in Comparative Example 3, 4 out of 10 samples had cracks 5 reaching the stitch connection portion. In Example 3, no crack 5 was found in 7 out of 10 samples. On the other hand, in Comparative Example 3, no crack 5 was observed in 6 out of 10 samples. As in Example 1 and Comparative Example 1 and Example 2 and Comparative Example 2, it was confirmed that Example 3 was superior, although it was not a clear difference. As a result, if the work-hardened aluminum foil 2 is used regardless of the type of the carbon layer 3 and the annealing step is added before the connecting step, the aluminum foil 2 is not wrinkled by the press of the laminating step and the connecting step is performed. It was confirmed by the press that no serious crack 5 was generated in the electrode body 1.

(Examples 4 and 5)
A sample of Example 4 was prepared. The sample of Example 4 is different from that of Example 1 in that the laminating step is performed using the work-hardened aluminum foil 2 and the bonding step is proceeded through the annealing step, and the laminating step and the connecting step include press working. Common. The sample of Example 4 is different from that of Example 1 in that the connection step is executed by using the cold pressure welding method. That is, in Example 4, the electrode body 1 and the flat plate portion 41 of the drawer terminal 4 were pressed by the pressing body in the stacking direction, and the electrode body 1 and the drawer terminal 4 were brought into close contact with each other. A drawer terminal 4 having a tab shape and entirely made of a flat plate portion 41 made of aluminum was connected to the electrode body 1.

Corresponding to the sample of Example 4, a sample of Comparative Example 4 which differs from Example 4 only in that the annealing step was omitted was also prepared.

Moreover, the sample of Example 5 was prepared. In the sample of Example 5, in addition to the point that cold pressure welding was used, the carbon layer 3 laminated on the aluminum foil 2 is different from that of Example 1. In the sample of Example 5, a carbon layer containing only carbon black as a carbon material was laminated on the aluminum foil 2. The method of laminating the carbon layer is the same as that of Example 3.

Corresponding to the sample of Example 5, a sample of Comparative Example 5 which differs from Example 5 only in that the annealing step was omitted was also prepared.

The contact resistance between the electrode body 1 and the extraction terminal 4 was measured with respect to the samples of Examples 4 and 5 and Comparative Examples 4 and 5. First, each electrode terminal of the resistance meter was connected to the flat plate portion 41 of the extraction terminal 4 and the electrode body 1. Then, while maintaining the position of the electrode body 1, the extraction terminal 4 was lifted by 0.8 mm to measure the contact resistance. As a resistance tester, a model number RM3545 manufactured by Hioki Electric Co., Ltd. was used. The measurement result shows the total value of the resistance value of the electrode body 1, the resistance value of the extraction terminal 4, and the connection resistance. The resistance value of the electrode body 1 and the resistance value of the extraction terminal 4 are the same values in Examples 4 and 5, and Comparative Examples 4 and 5.

The results of this contact resistance test are shown in Table 3 below. The resistance value was the average value of the three tests performed three times.
(Table 3)

Since the resistance value of the electrode body 1 and the resistance value of the extraction terminal 4 are the same values in Examples 4 and 5 and Comparative Examples 4 and 5, the difference in the measurement results shown in Table 3 is the difference in contact resistance. As shown in Table 3, the same contact resistance values were obtained in Examples 4 and 5, and the contact resistance values were much lower than those in Comparative Examples 4 and 5. As a result, if the work-hardened aluminum foil 2 is used regardless of the type of the carbon layer 3 and the bonding method is different, and the annealing process is added before the connection process, the aluminum foil 2 is pressed by the laminating process. It was confirmed that no wrinkles were generated and that no serious cracks 5 were generated in the electrode body 1 by the press in the connecting process.

1 Electrode body 1a Projection area 1b Peripheral area 11 Through hole 2 Aluminum foil 22 Core part 23 Oxide film layer 24 Metal base 25 Expanding layer 3 Carbon layer 4 Drawer terminal 4a Aluminum wire 4b Metal wire 41 Flat plate part 42 Bali 43 Round bar part 44 Inclined part 5 Crack 100 Press roller 200 Stitch needle 300 Pressing member

Claims (13)

A method for manufacturing an electrolytic capacitor including a lead-out terminal, an electrode body to which the lead-out terminal is connected, and an electrolyte interposed between the lead-out terminals.
A laminating process in which a carbon layer contained in a carbon material is formed on aluminum foil and pressed.
An annealing step of forming the aluminum foil and the carbon layer and annealing the electrode body which has undergone the laminating step,
A connection step of connecting the electrode body and the extraction terminal that have undergone the annealing step, including a pressurization step,
To have
A method for manufacturing an electrolytic capacitor. In the laminating step, the carbon layer is formed on the work-hardened aluminum foil.
The method for manufacturing an electrolytic capacitor according to claim 1. In the annealing step, when the aluminum foil is pressed until the through cracks occur, the ratio of the pressing force to the depth of the depression when the through cracks occur in the aluminum foil becomes 6.5 or more and 15 N / mm or less. , Annealing the electrode body,
The method for manufacturing an electrolytic capacitor according to claim 1 or 2, wherein the electrolytic capacitor is manufactured. In the annealing step, the electrode body is heat-treated at 250 ° C. or higher.
The method for manufacturing an electrolytic capacitor according to any one of claims 1 to 3, wherein the electrolytic capacitor is manufactured. The aluminum foil has an enlarged surface area and
In the laminating step, the carbon material contained in the carbon layer is made to enter the expanded surface region by the press.
The method for manufacturing an electrolytic capacitor according to any one of claims 1 to 4, wherein the electrolytic capacitor is manufactured. In the laminating step, at least a part of the lead-out terminal and the electrode body is metal-bonded by the pressurizing step.
The method for manufacturing an electrolytic capacitor according to any one of claims 1 to 5, wherein the electrolytic capacitor is manufactured. The electrode body has an oxide film on the surface of the aluminum foil, leaving a metal substrate on which the oxide film has not been formed.
In the laminating step, the carbon layer is formed on the oxide film, and the carbon layer is formed on the oxide film.
In the connection step, a crack is formed in the oxide film by the pressurizing step, and the drawer terminal and the metal substrate are brought into contact with each other through the crack.
The method for manufacturing an electrolytic capacitor according to any one of claims 1 to 5, wherein the electrolytic capacitor is manufactured. In the connection step, the oxide film in contact with the drawer terminal is crushed by the pressurization step.
7. The method for manufacturing an electrolytic capacitor according to claim 7. In the electrode body, a surface expansion layer is formed on the surface of the aluminum foil, and the oxide film is formed on the surface layer of the surface expansion layer.
In the connection step, the region in which the oxide film is not formed in the expansion layer is brought into contact with the drawer terminal through the crack by the pressurization step.
7. The method for manufacturing an electrolytic capacitor according to 7 or 8. In the connection step, the carbon layer is pushed into the crack by the pressurizing step, and the drawer terminal and the metal base material are brought into contact with each other through the carbon layer in the crack.
7. The method for manufacturing an electrolytic capacitor according to any one of 7 to 9. In the connection step, the electrode body and the extraction terminal are stitch-connected.
The method for manufacturing an electrolytic capacitor according to any one of claims 1 to 10. In the connection step, the electrode body and the lead-out terminal are cold-pressed.
The method for manufacturing an electrolytic capacitor according to any one of claims 1 to 10. An electrolytic capacitor including a lead-out terminal, an electrode body to which the lead-out terminal is connected, and an electrolyte interposed between the electrode bodies.
The electrode body is
Aluminum foil with an enlarged surface area and
A carbon layer containing a carbon material, which is pressed into the expanded area by press working, and which is pressed against the aluminum foil,
Have,
Annealed after the press working, and pressure-connected to the drawer terminal after annealing.
An electrolytic capacitor characterized by.

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