JP2018120952A - Capacitor and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a wound element improved in formability by pressing and increased in reliability by using an electrode foil subjected to high-magnification enlargement-of-area processing and chemical synthesis processing.SOLUTION: A method for manufacturing a capacitor which uses a capacitor element 2 arranged by a winding anode foil 8 comprises the steps of: forming a plurality of parting portions in a processed range 18 of a part of an etching layer of the anode foil 8 or the whole thereof; and pressing the element from its periphery to shape the element in such a form that a winding face has, as a part thereof, a curved portion 6 which is larger than the other portion in curvature.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technique for manufacturing a capacitor using a winding element such as an electrolytic capacitor.

  In a capacitor such as an electrolytic capacitor, the surface area of the electrode foil leads to the magnitude of the capacitance. The capacitor may be a capacitor element formed by winding an electrode foil.

  In addition, some capacitors use a flat capacitor element in which the shape of the winding surface of the element is an ellipse as a shape other than the cylindrical shape depending on the installation space of the equipment or device to be mounted. In order to deform the capacitor element in this way, for example, a method of pressing the capacitor element wound in a cylindrical shape from the outer peripheral side is taken.

  Regarding such a capacitor, there is a capacitor using a capacitor element in which an electrode foil is wound in an elliptical shape (for example, Patent Documents 1, 2, and 3).

JP 59-18628 JP 59-194420 A JP 2003-309041 A

By the way, valve metal foils, such as aluminum and copper, are used for the electrode foil used for an electrolytic capacitor. An etching layer is formed on the surface of the valve metal foil by a surface enlargement process, and a dielectric oxide film is formed thereon by a chemical conversion process. For example, in an electrode foil using aluminum, the aluminum itself is excellent in stretchability and flexibility, but the dielectric oxide film is hard and the stretchability and flexibility of the electrode foil is lowered. In particular, in recent years, in order to meet the demands for higher capacity, smaller size, and lighter electrolytic capacitors, the surface area of the electrode foil has been increased by increasing the surface area at a higher magnification. The area of the film also increases, and as a result, the electrode foil becomes more brittle and hardened, and the flexibility of the material itself is extremely reduced.
When a capacitor element is formed by winding such an electrode foil, when a part of the capacitor element is pressed so as to have a flat shape, a curved portion that is largely bent is formed. A large bending stress acts on the electrode foil in such a curved portion. At this time, the electrode foil may be cracked or broken on the foil surface. In addition, the capacitor element cannot follow such bending stress and acts as a restoring force to return to the original circular shape. In addition, since the followability is low, the capacitor element is laminated at the time of winding or molding by pressing. There is a possibility that a gap may be formed between the electrode foils. Thus, there exists a subject that the equivalent series resistance (ESR: Equivalent Series Resistance) of a capacitor | condenser becomes large because the clearance gap between electrode foils becomes large.

  Patent Documents 1, 2, and 3 do not disclose or suggest such a problem, and such a structure cannot be solved with those configurations.

Therefore, in view of the above-mentioned problems, the object of the present invention is to improve the formability by pressing and improve the reliability of the capacitor with respect to the wound element using the electrode foil that has been subjected to the surface enlargement treatment and chemical conversion treatment at a high magnification. There is.

  In order to achieve the above object, one aspect of a method for producing a capacitor according to the present invention is a method for producing a capacitor using an element in which an electrode foil is wound, and a part or all of an etching layer of the electrode foil is used. A step of forming a plurality of divided portions, and a step of pressing the element from the outer peripheral side and forming the curved portion having a curved portion having a larger curvature than the other portions on a part of the winding surface.

  In the method for manufacturing a capacitor, the electrode foil may include a plurality of divided portions, leaving a foil core portion.

  In order to achieve the above object, one aspect of the capacitor of the present invention is a capacitor using an element on which an electrode foil is wound, and the element has a larger curvature than a part of the winding surface in other parts. It is a shape provided with the formed curved part, and a plurality of divided parts are provided at least in part or all of the etching layer of the electrode foil of the curved part.

In the above capacitor, the electrode foil may include a plurality of the divided portions, leaving a foil core portion.

  According to the present invention, any of the following effects can be obtained.

  (1) By forming the dividing portion in part or all of the electrode foil, it is possible to prevent the electrode foil from being damaged when the capacitor element is pressed and molded.

  (2) By forming the dividing portion, the restoring force of the electrode foil against pressing is suppressed, and the moldability of the capacitor element is improved.

(3) By forming a split part in the electrode foil, the followability of the electrode foil during winding can be improved, and a gap can be prevented from being formed between the laminated electrode foils, and the equivalent series resistance of the capacitor Can be prevented.

It is a figure which shows the winding surface of the capacitor | condenser element which concerns on one embodiment. It is a figure which shows the structural example of electrode foil. It is a figure which shows an example of the winding process of electrode foil. It is a figure which shows an example of the shaping | molding process of a capacitor | condenser element. It is a figure which shows an example of the capacitor | condenser element using the electrode foil which is not provided with a parting part. It is a figure which shows the comparative example of the shaping | molding state of a capacitor | condenser element. It is a figure of the experimental example which shows the softness | flexibility of the electrode foil in which the part part was formed.

  [One embodiment]

  FIG. 1 shows a winding surface of a capacitor element according to an embodiment. The configuration illustrated in FIG. 1 is an example and is not limited to the configuration according to the present invention.

  The capacitor element 2 is an example of an element used for a capacitor such as an electrolytic capacitor, and is formed in a laminated state by winding an electrode foil formed in a horizontally long strip shape. Capacitor element 2 is formed in a shape including a curved portion in which the curvature of at least a part of the wound electrode foil is increased with respect to a part of the winding surface. For example, as shown in FIG. 1, the capacitor element 2 is formed in a so-called flat shape having an elliptical winding surface including a flat portion 4 having a small curvature and a curved portion 6 having a large curvature. The shape of the winding surface may be formed such that, for example, the length of the flat portion 4 is longer than or equal to the length of the curved portions 6 on both sides when viewed from the major axis direction of the ellipse.

  The capacitor element 2 includes an anode foil 8 and a cathode foil 10 as electrode foils, and is wound with a wide separator 12 interposed therebetween. For example, the separator 12 may be laminated so as to be disposed not only between the anode foil 8 and the cathode foil 10 but also on the innermost side or the outermost side of the wound capacitor element 2.

  In the capacitor element 2, tabs 14 and 16 are sandwiched inside the wound portion of the electrode foil. The tabs 14 and 16 are examples of terminal components for electrically connecting the capacitor to an electronic device (not shown), and are connected to, for example, an electrode foil. The tab 14 is connected to, for example, the anode foil 8 and becomes an anode terminal. Further, the tab 16 is connected to the cathode foil 10 to become a cathode terminal, for example.

  The capacitor element 2 is subjected to surface processing on at least the foil surface of the anode foil 8, for example. In the surface-processed anode foil 8, a plurality of dividing portions 20 (FIG. 2) are formed with respect to the etching layer formed on the electrode foil surface. This surface processing may be performed, for example, on part or all of the anode foil 8 forming the capacitor element 2. Among these, the processing range 18 in the case where the surface processing is performed on a part of the anode foil 8 includes at least a part to be the curved part 6 and / or a part to be a boundary between the curved part 6 and the flat part 4. Good. That is, the processing range 18 for the electrode foil includes a portion that is particularly susceptible to bending stress when the capacitor element 2 is processed or the periphery thereof.

  The surface treatment on the electrode foil may be performed not only on the anode foil 8 but also on the cathode foil 10 together with the anode foil 8.

  <Surface treatment of electrode foil>

  FIG. 2 shows an example of the surface state of the electrode foil. The surface state shown in FIG. 2 is an example.

For example, as shown in FIG. 2A, the anode foil 8 is formed with a linear dividing portion 20 along the short side direction of the electrode foil. For example, the dividing portion 20 may be arbitrarily set in length and formation interval, or the line direction may be determined in accordance with the forming method.
In addition, you may form the formation direction of the parting part 20 in the case where it follows the long side direction of electrode foil, or the short side direction of electrode foil, or the diagonal direction.

  As shown in FIG. 2B, the anode foil 8 has a core portion 22 having a predetermined thickness at the center in the thickness direction and an etching layer 24 formed on both ends thereof. The dividing part 20 is formed in the etching layer 24 of the anode foil 8. In the anode foil 8, a dielectric oxide film 25 is formed on the surfaces of the etching layer 24 and the dividing portion 20. The thickness of the core part 22 is, for example, 20 to 60 [μm], and the thickness of the etching layer 24 may be in the range of 40 to 200 [μm] in total.

  The dividing part 20 is formed, for example, by dividing the etching layer 24 at a predetermined depth from the surface of the anode foil 8 toward the core part 22. The formation depth of the dividing portion 20 may be set so as not to divide the core portion 22, and may be, for example, about the same as the depth of the etching layer 24 in the thickness direction of the electrode foil. It is not necessary to make the depths of all the dividing portions 20 uniform. In the formation of the dividing portion 20, for example, the etching layer 24 may be cracked in the thickness direction, and a method of tearing, cutting, notching, or carving the electrode foil surface using a predetermined jig may be used. In order to form a crack, for example, a method of applying a predetermined amount of pressure or tension to the set electrode foil surface with respect to the anode foil 8 subjected to surface enlargement treatment may be used.

  What is necessary is just to form the opening width of the parting part 20 so that it may become 0-50 [micrometers] or less, when the anode foil 8 is made flat, for example. Further, the dividing portion 20 is not limited to being formed in the etching layer 24 on both sides of the foil, but may be formed only on the surface side that is subjected to deformation or pressing by the winding direction of the anode foil 8 or the molding process of the capacitor element 2. . The dividing portion 20 has a so-called bellows shape on the surface of the anode foil 8 by forming a plurality of cuts. The formation position and range, the number of formations, and the formation interval of the divided portions 20 may be set according to, for example, the pressing force applied to the capacitor element 2 or the magnitude of bending stress due to deformation. In the present embodiment, the interval between the adjacent divided portions 20 is set to an average pitch of 220 [μm].

  As shown in FIG. 2C, for example, when the foil surface is in a bent state, the anode foil 8 in which the dividing portion 20 is formed in this manner is in an expanded state at the dividing portion 20a on the outer peripheral surface side of the bending. Thus, the stress caused by bending is released and is not propagated to the foil surface. Moreover, the bending stress etc. which are added to the inner peripheral side of a bend are absorbed because the dividing part 20b of the inner peripheral side of a bending | tightening is a closed state, or the divided parts 20b will be in a crimping state. As described above, the anode foil 8 formed with the dividing portion 20 is wound without breaking the etching layer 24 with respect to the bending treatment by winding even when the anode foil 8 is hardened and weakened by increasing the capacity. It can follow the shape.

  Furthermore, when a pressing force is applied to the foil surface of the anode foil 8 on which the dividing portion 20 is formed, the pressing force is dispersed to the outside from the cut of the dividing portion 20 at a position close to the pressing position, for example. As a result, it is possible to prevent the pressing force from propagating to the foil surface and causing cracks or the like in the end face portion of the foil.

  Moreover, when the capacitor | condenser element 2 is shape | molded by forming the parting part 20, the stress added at the time of this shaping | molding is disperse | distributed, and the followable | trackability of the anode foil 8 with respect to shaping | molding improves. Thereby, it is possible to prevent a restoring force from being generated in the molded capacitor element 2.

  <Capacitor manufacturing process>

  Next, an example of a capacitor manufacturing process will be described. FIG. 3 shows an example of an electrode foil winding process. The process illustrated in FIG. 3 is an example of a method for manufacturing a capacitor according to the present disclosure. Note that the processing procedure and processing steps shown in FIG. 3 are merely examples, and the present invention is not limited to the configuration according to the present invention.

  (A) In the capacitor manufacturing process, for example, an electrode foil forming process including a process of forming the dividing portion 20 of the anode foil 8, the laminated anode foil 8, cathode foil 10, and separator 12 are wound to form the capacitor element 2. And a process of pressing the wound capacitor element 2 to form a flat shape.

  As the anode foil 8 and the cathode foil 10, for example, an aluminum foil is used. After forming the etching layer 24 by the surface enlargement process on the surface of the anode foil 8, the dividing portion 20 is formed at a predetermined position on the surface of the anode foil 8. After the dividing portion 20 is formed, a dielectric oxide film 25 is formed on the surface of the dividing portion 20 by chemical conversion treatment.

In the winding process of the capacitor element 2, for example, as shown in FIG. 3, the anode foil 8 is placed on the separator 12 disposed on the outermost peripheral side, and the cathode foil 10 is placed with the separator 12 interposed therebetween. Laminated. On the foil surface of the anode foil 8, it is sufficient that the dividing portion 20 is formed at least in a portion disposed in the processing range 18 by winding. The dividing portion 20 has a length corresponding to the foil width of the anode foil 8 and is formed with a predetermined length in the foil short direction. Thereby, the dividing part 20 is formed in the range of the processing range 18 which becomes the curved part 6 of the capacitor element 2.
In addition, when forming the dividing part 20 in the cathode foil 10, what is necessary is just to form the dividing part 20 on the foil surface according to the part arrange | positioned in the process range 18, similarly to the case where it forms in the anode foil 8. FIG.

  Capacitor element 2 winds anode foil 8, cathode foil 10, and separator 12 around winding center 26 using, for example, a jig (not shown).

  In addition, a tab 14 or a tab 16 is connected to the capacitor element 2 on the electrode foil surfaces of the anode foil 8 and the cathode foil 10, respectively. In the tabs 14 and 16, for example, the flat portion 28 and the foil surface are connected by a stitch connection method or a cold welding method. Thus, the tabs 14 and 16 are connected to the capacitor element 2 so that the lead terminals 29 protrude from the same end face side.

  (B) As the forming process of the capacitor element 2, for example, the capacitor element 2 is pressed from the outside in a predetermined direction and is crushed to be formed into a flat shape including the flat portion 4 and the curved portion 6.

  For example, as shown in FIG. 4A, the capacitor element 2 is formed by winding an electrode foil with the winding center 26 as a reference, so that the winding surface has a circular cylindrical shape. The diameter W1 of the capacitor element 2 at this time is determined by the thickness of the electrode foil including the anode foil 8, the cathode foil 10, and the separator 12, the number of windings, and the tightening force of the winding process. At this time, the capacitor element 2 is laminated with the anode foil 8 in which the dividing portion 20 is formed as the processing range 18 on both ends via at least the winding center 26.

  In the step of forming the capacitor element 2, the outer peripheral side of the capacitor element 2 is pressed to form the curved portion 6 with respect to the processing range 18. For example, as shown in FIG. 4B, the pressing position may be set to a direction displaced by 90 degrees, for example, from the position of the machining range 18 of the capacitor element 2 with respect to the winding center 26 as a predetermined angle.

  At this time, a predetermined pressing force F <b> 1 is applied to the capacitor element 2 from both sides via, for example, the winding center 26. This pressing force F1 may be set based on, for example, the strength of the electrode foil. By this pressing, the capacitor element 2 is crushed in the pressing direction, and the shape of the winding surface is formed into a flat shape such as an ellipse. The width W2 on the short side of the winding surface at this time is determined by the magnitude of the pressing force F1. Therefore, the pressing force F1 for the capacitor element 2 may be set so that the capacitor element 2 can be accommodated with respect to the opening width of the case (not shown), for example.

  (C) After the forming process, for example, when the capacitor element 2 is housed together with the electrolyte in a case (not shown), the opening of the case is sealed by the sealing body. The sealing body is subjected to a caulking process by welding or pressing, for example, from the case exterior side.

  <Effect of one embodiment>

  According to such a configuration, the following effects can be obtained.

  (1) By forming the dividing portion 20 in a part or all of the anode foil 8 having a high capacity, it is possible to suppress the electrode foil from being damaged in the molding process of the capacitor element 2.

  (2) By forming the dividing portion 20, the restoring force of the electrode foil against pressing can be suppressed, and the capacitor element 2 can be formed into the intended shape.

  (3) By forming the dividing portion 20 in the electrode foil, the followability of the electrode foil during winding is improved. Thereby, it is possible to prevent a gap from being formed between the laminated electrode foils and to prevent an increase in the equivalent series resistance of the capacitor.

  (4) Since the moldability of the electrode foil is improved, the core portion 22 of the electrode foil can be further reduced in thickness, and the electrode foil can be increased in capacity.

  (5) By suppressing the damage of the electrode foil, the reliability of the electrode foil and the capacitor can be improved.

  (6) By providing flexibility to the electrode foil, the processing accuracy of the electrode foil can be improved and the probability of occurrence of nonconforming products can be reduced.

  (7) By preventing the electrode foil from being damaged by the molding process, it is possible to avoid the occurrence of a short circuit of the capacitor.

  [Comparative Example]

  FIG. 5 shows a case where the capacitor element 30 is formed using an electrode foil that does not include a dividing portion. FIG. 6 shows a comparative example of the molded state of the capacitor element 30.

  The capacitor element 30 shows a case where the anode foil 32 and the cathode foil 34 subjected to the surface enlargement treatment are wound. As described above, the anode foil 32 that has been subjected to the surface enlargement process or the chemical conversion process has become more brittle and hardened, and the flexibility of the material itself has been extremely reduced. Therefore, in the capacitor element 30 wound with the anode foil 32, the anode foil 32 can follow the winding shape in the curved portion 6 having a large bending rate, as shown in FIG. 5, for example. A large number of gaps 36 are generated. In addition, the anode foil 32 disposed in the curved portion 6 has an increased curvature due to, for example, being pressed from the outside during the molding process of the capacitor element 30, so that an excessive bending stress acts. This may cause cracks such as cracks and cracks on the surface of the anode foil 32. Such a crack may lead to a decrease in the capacitance of the capacitor, an increase in ESR (equivalent series resistance), and the like, which may lead to a decrease in the characteristics of the capacitor.

  On the other hand, the capacitor element 2 of the present invention arranges the anode foil 8 in which the dividing portion 20 is formed in the processing range 18 formed at least in the curved portion 6 where the curvature is large, so that cracks on the foil surface can be obtained. Can be avoided. Moreover, the anode foil 8 can prevent the formation of a gap in the wound capacitor element 2 by improving the followability to the forming of the capacitor element 2 by forming the dividing portion 20.

  Moreover, the case where the capacitor | condenser element 2 of this indication and the capacitor | condenser element 30 which wound the anode foil 32 which does not have a parting part are pressed and shape | molded is compared. For example, as shown in FIG. 6A, the capacitor elements 2 and 30 maintain a constant shape while being pressed together when a predetermined pressing force F1 is applied, and the width W3 on the short side becomes the same value. Then, when the application of the pressing force F1 is released after the forming process, the restoring force F2 acting on the anode foil 32 acts on the capacitor element 30 in the direction opposite to the pressing direction. As a result, the width W4 on the short side of the capacitor element 30 is significantly larger than the width W3 during pressurization.

  On the other hand, the capacitor element 2 of the present disclosure generates some restoring force, but the amount of restoration is smaller than that of the capacitor element 30 due to the improved followability to deformation caused by pressurization by the dividing portion 20.

  [Experimental Example 1]

  Next, the flexibility of the anode foil 8 by forming the dividing portion 20 will be described. An Erichsen value is shown as an index indicating the flexibility of the anode foil 8. As the anode foil 8, an average pitch of the divided part 20 is set to 70 [μm], 220 [μm], 950 [μm], 2100 [μm], 3100 [μm], and a divided part is formed as a comparative example. An anode foil was prepared, and an Eriksen test was performed on each anode foil. In the Eriksen test, a die having an inner diameter of 33 [mm] and an anode foil 8 and an anode foil not forming the dividing portion 20 are sandwiched by 10 [kN] using a crease presser, and a punch having a chisel shape is used. I pushed it in. The chisel-shaped punch is a spherical surface having a width of 30 [mm] and a tip of φ4 [mm]. The chisel part of the punch was pushed in along the short side direction of the electrode foil. The pushing speed of the punch was 0.5 [mm / min].

  The results of this Eriksen test are shown in FIG. FIG. 7 is a graph in which the horizontal axis represents the average pitch of the divided portions 20 and the vertical axis represents the Erichsen value. As shown in FIG. 7, the Erichsen value of the comparative example was 1.4 [mm], whereas the Eriksen value of the anode foil 8 in which the average pitch of the divided portions 20 was set to 3100 [μm] was 1.5. [Mm]. That is, it can be seen that by providing the dividing portion 20, the bending stress during winding is dispersed and the flexibility of the anode foil 8 is imparted.

  Further, when the average pitch of the divided portions 20 was 2100 [μm] or less, the Erichsen value was 1.7 [mm] or more, and a clear difference was generated as compared with the comparative example in which the divided portions 20 were not formed. That is, it can be seen that by providing the dividing portion 20 with an average pitch of 2100 [μm] or less, the bending stress during winding is well dispersed, and the anode foil 8 is given good flexibility.

  In particular, when the average pitch of the divided portion 20 is 950 [μm] or less, the Erichsen value is 2.0 [mm] or more, and the result is significantly superior to the comparative example in which the divided portion 20 is not formed. became. That is, it can be seen that by providing the dividing portion 20 at an average pitch of 950 [μm] or less, the bending stress during winding is very well dispersed, and the anode foil 8 is given very good flexibility.

  [Experimental example 2]

An experimental example of the restored state with respect to the pressure molding of the capacitor element 2 is shown.
In this experimental example, the restoration state of the capacitor element 2 using the anode foil 8 in which the dividing portion 20 was formed and the capacitor element 30 using the anode foil 32 in which the dividing portion was not formed was measured. Three each were formed, pressed from the side and formed into a flat shape, and then the pressed state was released, and the amount of restoration of the capacitor element was measured. The constituent materials and the manufacturing method are the same except that the parts other than the dividing part 20 are provided.

  In this experiment, the diameter of the capacitor element at the time of winding is set to 7 [mm], and the capacitor element is crushed until the diameter reaches 5.2 [mm]. Then, the deformation rate of the capacitor element after releasing the pressure is measured. The experimental results are as shown in Display 1 below.

  As shown in Table 1, the result is that the capacitor element 2 using the electrode foil in which the dividing portion 20 is formed is more than the capacitor element 30 (comparative example) using the electrode foil in which the dividing portion is not formed. The element width in the pressing direction is reduced. The return rate (restoration rate) from the element thickness of 5.2 [mm] at the time of pressing is 113.2 [%] on average when the dividing portion 20 is not provided, and is average when the dividing portion 20 is provided. It was 110.8 [%]. Thus, it was shown from the experimental results that by providing the dividing portion 20 on the electrode foil, the restoration rate after molding by pressing can be reduced, which is advantageous when molding into a flat shape.

  [Other Embodiments]

  Examples of modifications described above are listed below.

  (1) In the above-described embodiment, the dividing part 20 formed on the surface of the electrode foil has been shown to have a linear shape or a linear shape having a bent part at a part thereof. However, the present invention is not limited to this. The dividing part 20 may be, for example, a curved shape or a shape in which a plurality of lines are intersected.

  (2) In the above embodiment, when the dividing portions 20 are formed on both the front and back surfaces of the electrode foil, the dividing portions 20 are formed at positions facing each other via the core portion 22 of the electrode foil. However, the present invention is not limited to this. For example, the dividing portion 20 may be formed at different positions on the front surface and the back surface.

  (3) In the above embodiment, the capacitor element 2 having a flat winding surface has been shown to be elliptical, but the invention is not limited thereto. The capacitor element 2 may have any shape as long as the curved portion 6 having a large curvature is formed at least in part. And the processing range 18 which forms the parting part 20 in the part arrange | positioned at the curved part 6 should just be set to the anode foil 8. FIG.

  (4) Although the case where the dividing part 20 is formed on the curved part 6 side has been described in the above embodiment, the present invention is not limited to this. In addition to the bending portion 6, a processing range 18 in which the dividing portion 20 is formed may be set on either or both of the portion pressed by the molding process of the capacitor element 2 and the periphery of the pressing portion. Accordingly, the pressing force F1 pressed in the molding process can be released by the dividing portion 20, and the pressing force F1 can be prevented from propagating on the foil surface of the anode foil 8. Then, for example, the rupture of the anode foil 8 can be prevented by the pressing force F1.

  (5) In the above embodiment, the case where the dividing range 20 is provided in all of the anode foils 8 laminated by winding in the processing range 18 of the capacitor element 2 or the entire capacitor element 2 is shown. Not exclusively. For example, the anode foil 8 may form the dividing portion 20 at a portion disposed between the winding center 26 of the capacitor element 2 and a predetermined thickness. The curvature of the winding element increases toward the winding center 26, and conversely, the curvature decreases as the distance from the winding element increases. That is, the bending stress related to the anode foil 8 becomes larger on the winding center side. Therefore, the capacitor element 2 may be provided with the dividing portion 20 only in a portion close to the winding center 26 in accordance with, for example, resistance to bending stress on the foil surface of the anode foil 8. In addition, what is necessary is just to judge the tolerance to the bending stress of foil, for example based on the hardening degree and weakness degree of the surface of the anode foil 8. FIG.

As described above, the most preferable embodiment of the present invention has been described. However, the present invention is not limited to the above description, and is described in the claims or disclosed in the specification. It goes without saying that various modifications and changes can be made by those skilled in the art based on the gist, and such modifications and changes are included in the scope of the present invention.

According to the capacitor of the present invention and the method for manufacturing the same, by forming a cut portion by dividing the surface layer in a part or all of the anode foil 8 that is wound and shaped into a flat shape, It is useful to prevent the occurrence of cracks such as cracks and cracks on the foil surface and to prevent the ESR from being lowered by not forming a gap between the laminated electrode foils.

2, 30 Capacitor element 4 Flat part 6 Curved part 8, 32 Anode foil 10, 34 Cathode foil 12 Separator 14, 16 Tab 18 Processing range 20, 20a, 20b Dividing part 22 Core part 24 Etching layer 25 Dielectric oxide film 26 Winding Center of rotation 28 Flat part 29 Lead terminal 36 Clearance

Claims (4)

A capacitor manufacturing method using an element in which an electrode foil is wound,
Forming a plurality of divided portions in a part or all of the etching layer of the electrode foil;
The step of pressing the element from the outer peripheral side, and forming the curved part having a larger curvature than the other part in a part of the winding surface,
A method for producing a capacitor, comprising:   The method of manufacturing a capacitor according to claim 1, wherein the electrode foil includes a plurality of divided portions, leaving a foil core portion. A capacitor using an element in which an electrode foil is wound,
The element has a shape including a curved portion formed in a part of the winding surface with a larger curvature than the other part,
A capacitor comprising a plurality of divided portions at least in part or all of the etching layer of the electrode foil of the curved portion. The capacitor according to claim 3, wherein the electrode foil includes a plurality of the dividing portions except for a foil core portion.

Images