JP2021197467A - Capacitor manufacturing method and capacitor - Google Patents

Abstract

To provide a technique for protecting electrode foil from damage caused by connection with a terminal.SOLUTION: A manufacturing method of a capacitor which connects electrode foil and a terminal includes: a step of superimposing and holding a terminal 2 and electrode foil 1 which has a dielectric oxide film on the surface of a plurality of divided portions formed in an etching layer; a step of inserting a stitch needle 3 into the electrode foil 1 from the terminal 2 side and inserting a cut-up piece 7 generated in the terminal 1 into the electrode foil 1; and a step of pressure-molding the cut-up piece 7 by a first molding die 8 having a pressing surface portion 81 in contact with the terminal 2 and a protruding pressing surface portion 82 protruding from the pressing surface portion 81, and a second molding die 9 for deforming the cut-up piece 7 from the electrode foil 1 side. In the step of pressure-molding, the protruding pressing surface portion 82 presses the end portion of the terminal 2 to form a thin-walled portion 27.SELECTED DRAWING: Figure 1

Description

The present invention relates to a terminal technique for an electrode foil used for an electrolytic capacitor or the like.

For capacitors such as electrolytic capacitors, connect the terminals to the electrode foil. As a technique for connecting terminals to the electrode foil, for example, there is stitch connection. In this stitch connection, the flat plate portion of the terminal is superposed on the electrode foil, and the stitch needle is penetrated from the flat plate portion side. The cut-up piece on the terminal side generated following the penetration of the stitch needle is passed through the electrode foil, and the cut-up piece is formed on the electrode foil side and pressed against the electrode foil to connect the terminal. Stitch connection is an excellent connection technology that uses the minimum number of members only for terminals and electrode foils, and also utilizes the moldability and retention of terminal materials for connection processing.

Regarding this stitch connection, it is disclosed that the electrode foil and the plate-shaped terminal are overlapped and sandwiched integrally, a through hole is formed in both, and a cut-up piece on the terminal side penetrated through the electrode foil is formed on the electrode foil. (For example, Patent Document 1). In addition, the tab is placed on the electrode foil and placed in the lower mold, the stitch needle is penetrated from the tab toward the electrode foil, and the cut piece that penetrates the electrode foil from the tab is pushed up toward the upper mold and the pin is pressed. It is known to connect a tab and an electrode foil (for example, Patent Document 2).

By the way, as the electrode foil used for the electrolytic capacitor, a valve metal foil such as aluminum or copper is used. An etching layer is formed on the surface of the valve metal foil by a surface expansion treatment, and a dielectric oxide film is formed on the etching layer by a chemical conversion treatment. For example, in an electrode foil using aluminum, aluminum itself is excellent in stretchability and flexibility, but the dielectric oxide film is hard, and the stretchability and flexibility of the electrode foil are lowered. In particular, in recent years, in order to meet the demand for higher capacity of electrolytic capacitors, the surface area of the electrode foil has been increased by performing a surface enlargement treatment with a higher magnification. As the surface area of the electrode foil increases, the area of the dielectric oxide film also increases, and as a result, the electrode foil becomes weaker and hardens, and the flexibility of the material itself is extremely reduced. In the stitch connection in which the terminal is overlapped on the electrode foil and the stitch needle is penetrated, stress is applied to the electrode foil when the stitch needle is penetrated or when the cut-up piece is pressed, and this stress may cause cracking or breakage. was there.

In order to solve such a problem, a plurality of divided portions are formed at least at the connection portion with the terminal with respect to the dielectric oxide film on the surface of the etching layer formed on the electrode foil to give the electrode foil flexibility. It is known that the generation of cracks due to pressing is suppressed and the expansion of cracks is prevented (for example, Patent Document 3).

Special Publication No. 44-006110 Japanese Unexamined Patent Publication No. 7-106203 Japanese Unexamined Patent Publication No. 2018-120939

By the way, in recent years, miniaturization of the electrolytic capacitor has been required, and as shown in FIG. 6, the distance L between the tip of the cut-up piece 7 of the terminal 2 and the edge portion 15 of the electrode foil 1 becomes smaller. When the stitch connection process is performed in such a state, a part or all of the stress X applied by the punching process of the stitch needle and the folding process of the cut-up piece 7 is stitch-connected from the tip of the cut-up piece 7 to the electrode foil 1. Propagate around the part. Then, in the electrode foil 1, for example, the stress X is released from the edge portion 15 side of the electrode foil 1 near the stitch connection portion. Since the cross-sectional portion of the edge portion 15 of the electrode foil 1 is weaker than the electrode foil surface, the electrode foil 1 is liable to be cracked or divided toward, for example, the stitch connection portion, and a large crack 19 is formed. There is a risk of Such cracks 19 lead to, for example, a decrease in the capacity of the capacitor, an increase in ESR (equivalent series resistance), and the like, which leads to a decrease in the characteristics of the capacitor.

Therefore, the present invention has been proposed to solve the above problems, and an object thereof is to connect a terminal to an electrode foil which has been subjected to high-magnification surface enlargement treatment and chemical conversion treatment to form a divided portion. The purpose is to prevent cracks and breaks in the processing to be performed and to improve the reliability of the capacitor.

In order to achieve the above object, the method for manufacturing a capacitor of the present invention includes a step of superimposing and holding an electrode foil and a terminal having a dielectric oxide film on the surface of a plurality of divided portions formed in an etching layer, and the terminal side. A step of inserting a stitch needle into the electrode foil and inserting a cut-up piece generated in the terminal into the electrode foil, a pressing surface portion in contact with the terminal, and a protruding pressing surface portion protruding from the pressing surface portion. The step of pressure-molding comprises a step of pressure-molding the cut-up piece by a first molding die having the first molding die and a second molding die for deforming the cut-up piece from the electrode foil side. The protruding pressing surface portion presses the end portion of the terminal.

Further, the pressing surface on the end side of the terminal by the first molding die may be orthogonal to the divided portion formed in the width direction of the electrode foil.

Further, before the step of inserting the stitch needle into the electrode foil from the terminal side and inserting the cut-up piece generated in the terminal into the electrode foil, a step of forming a through hole in the electrode foil in advance. , The step of inserting the cut-up piece generated in the terminal by inserting the stitch needle from the terminal side into the through hole of the electrode foil may be included.

Further, in the step of pressure molding the cut piece from the electrode foil side with a second molding die and connecting the cut piece to the electrode foil, the first molding die for fixing the terminal from the terminal side. The first molding may press both ends of the flat plate portion of the terminal.

In order to achieve the above object, the capacitor of the present invention has an electrode foil having a through hole, a terminal having a cut-up piece to be inserted through the through hole, and the through hole of the electrode foil. By molding the cut-up piece, a folded connection portion connecting the electrode foil and the terminal and a stitch on the end side of the flat plate portion of the terminal between the edge portion of the electrode foil and the cut-up piece. It is characterized by being a thin-walled portion formed by being pressed during the process.

Further, the thin-walled portion may be formed on both ends of the flat plate portion of the terminal.

According to the present invention, by pressing the end portion of the terminal when pressing the cut-up piece, the stress applied to the electrode foil is not transmitted to the edge portion of the electrode foil, and the occurrence of cracks due to the pressing is suppressed. It is possible to prevent the expansion of cracks.

It is a figure which shows the manufacturing process which concerns on 1st Embodiment. It is a figure which shows an example of the surface state of an electrode foil. It is a figure which shows the connection part of the electrode foil and the terminal which concerns on 1st Embodiment. It is a figure which shows the drilling process which concerns on 2nd Embodiment. It is a figure which shows the manufacturing process which concerns on other embodiment. It is a figure which shows the connection state of the conventional terminal and an electrode foil.

Hereinafter, the electrolytic capacitor according to the embodiment of the present invention will be described. In this embodiment, an electrolytic capacitor having an electrolytic solution will be described as an example. The present invention is not limited to the embodiments described below.

[First Embodiment]
The first embodiment of the present invention will be described with reference to FIG. FIG. 1 shows an example of a method of connecting an electrode foil and a terminal according to the first embodiment of the present invention, and is a cross-sectional view of the electrode foil in the width direction. The configuration shown in FIG. 1 is an example, and is not limited to the configuration according to the present invention.

The electrode foil 1 according to the first embodiment of the present invention is, for example, mainly an electrode foil on the anode side, and a high-magnification etching layer 11 is formed on the surface of the electrode foil 1 ((FIG. 2). B)). As shown in FIG. 2A, a linear divided portion 12 is formed along the width direction (short side direction) of the electrode foil 1. In FIG. 2, X in (A) represents the width direction (short direction) of the electrode foil 1, and Y represents the length direction of the electrode foil 1. For example, the length and the forming interval of each of the dividing portions 12 may be arbitrarily set, or the line direction may be determined according to the forming method thereof. The forming direction of the divided portion 12 may be along the long side direction of the electrode foil 1, the long side direction of the electrode foil 1, or the diagonal direction.

As shown in FIG. 2B, a core portion 13 having a predetermined thickness is formed at the center in the thickness direction, and an etching layer 11 having an enlarged surface treatment is formed on both surfaces thereof. The divided portion 12 is formed in the etching layer 11 of the electrode foil 1. The electrode foil 1 has a dielectric oxide film (not shown) formed on the surfaces of the etching layer 11 and the divided portion 12. The thickness of the core portion 13 may be, for example, 20 to 60 [μm], and the thickness of the etching layer 11 may be in the range of 40 to 200 [μm] in total on both sides.

The divided portion 12 is formed by, for example, dividing the etching layer 11 from the surface of the electrode foil 1 toward the core portion 13 at a predetermined depth. The forming depth of the divided portion 12 may be such that the core portion 13 is not divided, and may be set to the same degree as the depth of the etching layer 11 with respect to the thickness direction of the electrode foil 1, for example. It is not necessary to make the depths of all the dividing portions 12 uniform. In forming the divided portion 12, for example, in addition to cracking the etching layer 11 in the thickness direction, a method of tearing, cutting, notching, or engraving the surface of the electrode foil 1 using a predetermined jig may be used. In order to form cracks, for example, a method of applying a predetermined amount of pressure or tension to the surface of the electrode foil 1 that has been subjected to surface expansion treatment or chemical conversion treatment may be used.

The opening width of the divided portion 12 may be formed so as to be 0 to 50 [μm] or less when the electrode foil 1 is flattened, for example. Further, the divided portion 12 is not limited to being formed on the etching layers 11 on both sides of the electrode foil 1, and may be formed only on the surface side that is deformed or pressed in the winding direction of the electrode foil 1 or in the stitching process. The divided portion 12 has a so-called bellows shape on the surface of the electrode foil 1 by forming a plurality of notches. The formation position and range of the divided portion 12, the number of formations and the formation interval thereof may be set according to, for example, the magnitude of the pressing force applied to the electrode foil 1 or the bending stress due to deformation. The distance between the adjacent dividing portions 12 may be, for example, an average pitch of 220 [μm].

As an example, the terminal 2 connected to the electrode foil 1 is composed of an aluminum wire and a metal wire 21, and the aluminum wire and the metal wire 21 are connected by arc welding or the like. The aluminum wire includes a round bar portion 22 having a substantially cylindrical shape and a flat plate portion 23 formed by pressing the round bar portion 22. A flat plate portion 23 is formed on the flat plate portion 23 side of the round bar portion 22. An inclined portion 24 whose thickness is linearly reduced to the thickness of the portion 23 is formed. A flat plate portion 23 is arranged on the electrode foil 1.

Next, an example of the capacitor manufacturing process will be shown. The manufacturing process of this capacitor includes, for example, a process of forming the electrode foil 1 including the formation of the divided portion 12 on the anode foil, and a process of connecting the terminal 2 to the electrode foil 1. The forming process of the electrode foil 1 includes, for example, a process of forming an aluminum foil or the like, a process of forming an etching layer 11 on the surface on the anode side by a surface expansion treatment, and a process of forming a dielectric oxide film by a chemical conversion treatment. .. Then, after forming the divided portion 12 at a predetermined position on the surface of the electrode foil 1, a rechemical conversion treatment may be performed to form a dielectric oxide film on the surface of the divided portion 12.

In the connection process between the electrode foil 1 and the terminal 2, for example, as shown in FIG. 1A, the flat plate portion 23 of the terminal 2 is superposed on the upper surface of the electrode foil 1. The electrode foil 1 and the terminal 2 are placed on the second holding jig 5, and the first holding jig 4 is installed on the upper surface of the terminal 2. That is, the electrode foil 1 and the terminal 2 are sandwiched and held between the first holding jig 4 and the second holding jig 5.

Through holes 41 and 51 are formed in the first holding jig 4 and the second holding jig 5, respectively. A stitch needle 3 is arranged at the center of the through hole portion 41 of the first holding jig 4. The stitch needle 3 is provided with, for example, a cylindrical shaft portion 31 and an acute-angled pyramidal tip portion 32.

In the step of drilling the stitch needle 3, as shown in FIG. 1B, the flat plate portion 23 of the electrode foil 1 and the terminal 2 is held between the first holding jig 4 and the second holding jig 5. The stitch needle 3 is inserted through the electrode foil 1 and the flat plate portion 23 from the terminal 2 side. The drilling step in the first embodiment is a step of inserting the stitch needle 3 into the terminal 2 and the electrode foil 1 and inserting the cut-up piece 6 of the electrode foil 1 and the cut-up piece 7 of the terminal 2 into the electrode foil 1. This is just one example. By this insertion, a cut-up piece 7 is generated in the flat plate portion 23 cut by the tip portion 32 of the stitch needle 3, and a cut-up piece 6 is generated in the electrode foil 1. At this time, the cut pieces 6 and 7 are formed on the back side of the electrode foil 1 (the surface side placed on the second holding jig).

After the stitch needle 3 is used to form the raised pieces 6 and 7 on the back side of the electrode foil 1, the stitch needle 3 and the first holding jig 4 are retracted. After retracting the stitch needle 3 and the first holding jig 4, the first molding die 8 is arranged above the electrode foil 1, and the second molding die 9 is arranged below the electrode foil 1. To. A pressing surface 91 portion is formed in the second molding die 9. The pressing surface portion 91 is applied to the cut-up pieces 6 and 7 and pressed between the first molding die 8 and the second molding die 9, so that the cut-up pieces 6 and 7 are on the back surface side of the electrode foil 1. Mold to contact with.

When the cut pieces 6 and 7 are pressed by the second molding die 9, the electrode foil 1 and the terminal 2 are fixed from above by the first molding die 8. A pressing surface portion 81 is formed on the first molding die 8. The portion of the pressing surface portion 81 corresponding to the end portion 25 side of the terminal 2 is provided with a protruding pressing surface portion 82 projecting from the other surface portion of the pressing surface portion 81. Pressure is applied to the end portion 25 side of the terminal 2 and the electrode foil 1 overlapping the end portion 25 side by the projecting pressing surface portion 82. The stress when the cut pieces 6 and 7 are pressed against the electrode foil 1 by the pressing surface portion 91 of the second molding die 9 propagates toward the edge portion 15 of the electrode foil 1, but is propagated by the protruding pressing surface portion 82. When the electrode foil 1 is pressed, its propagation is prevented from propagating to the edge portion 15.

At this time, it is preferable that the protruding pressing surface portion 82 is in a orthogonal direction with respect to the direction in which the dividing portion 12 is formed. The stress generated when the cut pieces 6 and 7 are pressed by the second molding die 9 easily propagates along the forming direction of the dividing portion 12, but the projecting pressing surface portion 82 perpendicular to the dividing portion 12 By pressing against the electrode foil 1, it is easy to cut off the propagating stress.

The cut pieces 6 and 7 are pressed against the back surface side of the electrode foil 1 and connected to the electrode foil 1, for example, as shown in FIG. 1 (D). As a result, the folded connection portion 26 that brings the terminal 2 into close contact with the electrode foil 1 is formed.

After forming the folded-back connecting portion 26, the second holding jig 5, the first molding die 8, and the second molding die 9 are retracted, and the stitch connection is completed. As shown in FIGS. 1 (E) and 5 in FIG. 1, the terminal 2 to which the stitch connection is completed has a through hole 10 formed in the electrode foil 1 and the flat plate portion 23 of the terminal 2. FIG. 3 is a diagram showing a connection portion between the electrode foil 1 and the terminal 2 in the first embodiment. Further, the thin-walled portion 27 whose thickness on the end portion 25 side of the terminal 2 pressed by the pressing surface portion 91 is thinner than that before the stitch connection step is cut up so that the tip of the piece 7 and the edge portion 15 of the electrode foil 1 are formed. It is formed to block the space.

After this stitching treatment, a chemical conversion treatment for further forming a dielectric oxide film may be performed on the surface of the divided portion 12.

In this stitch connection process, pressure received from the terminal 2 deformed by, for example, perforation of the stitch needle 3 or pressure received by pressing the second molding die 9 is applied to the electrode foil 1. Then, the divided portion 12 of the electrode foil 1 disperses the applied pressure in the range including the folded connection portion 26 or a peripheral portion thereof. However, with the miniaturization of the capacitor, when the distance L between the tip of the cut-up piece 7 of the terminal 2 and the edge 15 of the electrode foil 1 becomes smaller, more specifically, when it becomes less than 2.0 mm, the applied stress is applied. Is easily propagated to the edge portion 15 of the electrode foil 1 by the dividing portion 12. As in the first embodiment, the protrusion pressing surface portion 91 presses between the folded connection portion 26 to which the pressure received by the pressing of the second molding die 9 is applied and the edge portion 15 of the electrode foil 1. This prevents the stress propagated from the folded-back connection portion 26 from propagating to the edge portion 15 of the electrode foil 1.

According to the first embodiment, even if the distance L between the tip of the cut-up piece 7 of the terminal 2 and the edge portion 15 of the electrode foil 1 becomes small, the occurrence of cracks due to pressing is suppressed, and the expansion of cracks is increased. Can be prevented.

Further, by suppressing the damage of the electrode foil 1, the reliability of the electrode foil 1 and the capacitor can be improved.

Further, by suppressing the propagation of stress generated during molding of the cut-up pieces 6 and 7 generated between the edge portion 15 of the electrode foil 1 and the end portion 25 of the terminal 2, the processing accuracy can be improved and the non-conforming product can be improved. Can reduce the probability of occurrence of.

In addition, it becomes easy to adjust the force applied during the molding process of the folded connection portion 26 in the stitch connection.

Further, by reducing the damage occurrence rate of the electrode foil 1, it is possible to speed up the processing process and the product check process.

By preventing damage to the electrode foil 1 due to the connection of the terminals 2, the aging process after processing can be omitted or only a light process can be performed, and the capacitor manufacturing process can be speeded up.

[Second Embodiment]

As shown in FIG. 3, an electrode foil having a through hole 14 formed in advance in a portion where the stitch needle 3 is pierced may be used before the above-mentioned stitching step.

In the second embodiment, as shown in FIG. 4A, a through hole 14 is formed in the electrode foil 1 before the stitch needle 3 is inserted. The through hole 14 is, for example, a quadrangle. The through hole 14 is formed by preforming the electrode foil 1.

The electrode foil 1 is placed on the upper surface of the second holding jig 5, and the through hole 14 is arranged in the center of the through hole portion 51 of the second holding jig 5. A flat plate portion 23 of the terminal 2 is installed on the upper surface of the electrode foil 1, and the through hole 14 is aligned with the central axis of the flat plate portion 23. That is, the connection portion of the flat plate portion 23 with the electrode foil 1 is overlapped with the through hole 14. A flat plate portion 23 is installed on the upper surface of the electrode foil 1, and a first holding jig 4 is installed on the flat plate portion 23.

Next, in the drilling step, as shown in FIG. 4B, the terminal 2 is relative to the electrode foil 1 and the terminal 2 held between the first holding jig 4 and the second holding jig 5. The stitch needle 3 is inserted from the side. By this insertion, in this embodiment, a cut-up piece 6 is generated in the through hole 14 of the electrode foil 1 in the flat plate portion 23 cut by the tip portion 32 of the stitch needle 3. That is, the through hole 14 may have a shape and a size assuming a cut-up piece 6 generated in the flat plate portion 23 by inserting the stitch needle 3.

Then, as in the first embodiment, the electrode foil 1 and the flat plate portion 23 are pressed together with the cut-up piece 6 of the flat plate portion 23 by press working with the first molding die 8 and the second molding die 9. The cut-up piece 6 is formed into a flat shape by pressure contact to form a folded connection portion 26, and the electrode foil 1 and the terminal 2 are connected to each other.

With such a configuration, it is possible to join the terminal 2 and the electrode foil 1 so that the cut-up piece 6 and the core portion 13 of the electrode foil 1 are in direct contact with each other on the inner peripheral surface of the through hole 14. be. With such a configuration, good electrical connectivity can be obtained even if the anode foil is an electrode foil having a dielectric oxide film formed on its surface. That is, while the dielectric oxide film formed on the surface of the electrode foil 1 has an insulating property, if a through hole 14 is formed in the electrode foil 1, the through hole 14 allows the aluminum base material to be formed from the electrode foil 1. Can be exposed. Since the exposed surface of this base material can be brought into direct contact with the terminal 2 and can be connected without interposing the cut-up piece 7 of the electrode foil 1 on which the dielectric oxide film is formed, the electrode foil 1 and the terminal 2 can be connected to each other. The electrical resistance between can be reduced.

Further, in this embodiment, since the through hole 14 is formed in advance in the electrode foil 1, it is possible to suppress the generation of stress on the electrode foil 1 caused by inserting the stitch needle 3, and the electrode foil 1 can be further suppressed. Can prevent cracking.

The shape of the through hole 14 is not limited to a quadrangle. The through hole 14 may be circular or triangular, or may have a polygonal shape such as a pentagon.

[Experimental example]

An experimental example in which the terminal end is pressed and fixed by a die provided with a protruding pressing surface portion when the terminal is stitch-connected to the electrode foil on which the divided portion is formed and the cut-up portion is pressed. Is shown.

In this experimental example, the electrode foil having a through hole formed in advance as shown in the second embodiment was used. The L (see FIG. 6) between the edge of the electrode foil and the end of the terminal is set to 0.6 mm, and a stitch connection step using a molding die provided with a protruding pressing surface portion and a protruding pressing surface portion are formed. In the stitch connection step using a flat molding die, 50 stitches were connected to each. Then, the state of cracks generated between the edge of each electrode foil and the end of the terminal was confirmed. When the stitch connection step using the molding die provided with the projecting pressing surface portion was performed, a thin-walled portion thinner than the other portion of the flat plate portion of the terminal was formed at the end portion of the terminal. On the other hand, when the stitch connection step using a flat molding die in which the protruding pressing surface portion was not formed was performed, a thin-walled portion was not formed at the end portion of the terminal. The conditions are the same except for the presence or absence of the protruding pressing surface portion of the second molding die. The results of the experimental examples are shown in Table 1 below.

As a result of this experiment, when the cut-up piece was pressed, the number of pieces without cracks due to stitch connection was increased from 17 to 50 by pressing the end of the terminal, which was a significant increase.

From the above results, by pressing the end portion of the terminal when pressing the cut-back portion, the influence of the stitch connection on the electrode foil can be significantly reduced. Further, by forming the divided portion, it is possible to eliminate or reduce the repair of the electrode foil after stitch connection, and it is possible to reduce the number of electrode foils that cannot be used due to cracks.

[Other embodiments]

(1) In the above embodiment, the connection between the electrode foil and the terminal is illustrated, but this connection uses an electrolytic capacitor, a solid electrolytic capacitor using a solid electrolyte as the electrolyte, and both an electrolytic solution and a solid electrolyte as the electrolyte. It can be applied to the connection between the terminals of various capacitors such as so-called hybrid capacitors and electric double layer capacitors and the electrode foil.

(2) In the above embodiment, the connection between the electrode foil and the terminal is described, but the method for manufacturing the capacitor includes other steps such as a winding step of the electrode foil and a sealing step in the outer case. Needless to say.

(3) In the above embodiment, the first holding jig 4 is separated from the terminal 2, the first molding die 8 is placed on the terminal 2 again, and the pressing process is performed. Similar to the first molding die 8, the protruding pressing surface portion 82 may be formed at a position corresponding to the end portion 25 of the terminal 2 of the jig 4, and the flat plate portion 23 may be continuously pressed during the stitch connection process.

(4) In the above embodiment, the first molding die 8 is provided with a protruding pressing surface portion 82 projecting from another surface portion of the pressing surface portion 81 as a means for pressing the end portion 25 of the terminal 2. However, it suffices if the end portion 25 of the terminal 2 can be pressed in the step of pressing the cut-up pieces 6 and 7 against the electrode foil 1 with the second molding die 9, and the present invention is not limited to this. For example, the shape may be such that only the end portion 25 of the terminal 2 is pressed, or the end portion 25 of the flat plate portion 23 of the terminal 2 and the end portion of the flat plate portion 23 on the inclined portion 24 side are pressed. Further, the first molding die 8 may be configured to divide a molding die that presses the end portion 25 of the terminal 2 and a molding die that presses a portion other than the end portion 25 of the flat plate portion 23.

(5) In the above embodiment, the protruding pressing surface portion 82 is provided only on the end portion 25 side of the terminal 2, but may be further provided on the inclined portion 24 side of the terminal 2. Specifically, as shown in FIG. 4A, the thin portion 27 is located between the tips of the cut pieces 6 and 7 near the inclined portion 24 and the edge portion 15 near the inclined portion 24 of the electrode foil 1. The protruding pressing surface portion 82 is provided on the pressing surface portion 81 of the first molding die 8 so as to form. As shown in FIG. 5B, the terminal 2 stitch-connected by the manufacturing process according to this embodiment also has a thin-walled portion 27 formed on the inclined portion 24 side of the flat plate portion 23. By doing so, it is possible to suppress cracks on the edge portion 15 side close to the inclined portion 24 of the electrode foil 1.

1 Electrode foil 11 Etching layer 12 Dividing part 13 Core metal part 14 Through hole 15 Edge part 2 Terminal 21 Metal wire 22 Round bar part 23 Flat plate part 24 Inclined part 25 End part 26 Folded connection part 27 Thin-walled part 3 Stitch needle 31 Shaft part 32 Tip 4 First holding jig 41 Through hole 5 Second holding jig 51 Through hole 6 Cut-up piece (electrode foil)
7 Cut and raised piece (terminal)
8 First molding die 81 Pressing surface portion 82 Protruding pressing surface portion 9 Second molding die 91 Pressing surface portion 10 Through hole

Claims (6)

It is a method of manufacturing a capacitor that connects the electrode foil and the terminal.
A step of superimposing and holding an electrode foil and a terminal having a dielectric oxide film on the surface of a plurality of divided portions formed in an etching layer, and
A step of inserting a stitch needle into the electrode foil from the terminal side and inserting a cut-up piece generated in the terminal into the electrode foil.
The cutting is performed by a first molding die having a pressing surface portion in contact with the terminal and a protruding pressing surface portion protruding from the pressing surface portion, and a second molding die for deforming the cut-up piece from the electrode foil side. The process of pressure molding the raised piece and
The method for manufacturing a capacitor, characterized in that, in the step of pressure molding, the protruding pressing surface portion presses the end portion of the terminal. The capacitor according to claim 1, wherein the pressing surface on the end side of the terminal by the first molding die is orthogonal to the divided portion formed in the width direction of the electrode foil. Production method. Before the step of inserting the stitch needle into the electrode foil from the terminal side and inserting the cut-up piece generated in the terminal into the electrode foil, a step of forming a through hole in the electrode foil in advance.
A step of inserting a cut-up piece generated in the terminal by inserting the stitch needle from the terminal side into the through hole of the electrode foil.
The method for manufacturing a capacitor according to claim 1 or 2, wherein the capacitor comprises. In the step of pressure molding the cut piece from the electrode foil side with a second molding die and connecting it to the electrode foil.
The first molding die for fixing the terminal from the terminal side, wherein the first molding die presses both ends of the flat plate portion of the terminal according to any one of claims 1 to 3. How to make capacitors. Electrode foil with through holes and
A terminal on which a cut-up piece to be inserted through the through hole is formed,
A folded connection portion for connecting the electrode foil and the terminal by molding the cut-up piece inserted through the through hole of the electrode foil.
A thin-walled portion formed by being pressed during the stitching process between the edge portion of the electrode foil and the cut-up piece on the end side of the flat plate portion of the terminal.
Capacitors characterized by being equipped with. The capacitor according to claim 5, wherein the thin-walled portions are formed on both ends of the flat plate portion of the terminal.

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