JP2011009375A - Laminated electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated electrolytic capacitor strength of which against pressure applied in a laminating direction is increased while securing effective area of electrode foils.SOLUTION: The laminated electrolytic capacitor 1 includes an electrode laminate 2 formed by laminating an anode foil 4 and a cathode foil 5 alternately with a separator 6 interposed, and an anode lead 14 and a cathode lead 15. A lead connection part 9 to which the anode lead 14 is bonded is provided at one edge of the anode foil 4, and a cut part 10 is provided at the opposite-side edge of the anode foil 4. A lead connection part 11 to which the cathode lead 15 is bonded is provided at one edge of the cathode foil 5, and a cut part 12 is provided at the opposite-side edge of the cathode foil 5. The electrode laminate 2 has the anode foil 4 and cathode foil 5 laminated alternately with the separator 6 interposed so that the lead connection part 9 of the anode foil 4 and the cut part 12 of the cathode foil 5 correspond to each other, and the cut part 10 of the anode foil 4 and the lead connection part 11 of the cathode foil 5 correspond to each other.

Description

  The present invention relates to a multilayer electrolytic capacitor having a structure in which an anode foil and a cathode foil are alternately laminated via a separator.

  In recent years, with the progress of miniaturization of multilayer electrolytic capacitors, optimization of the structure for attaching leads to the electrode foil is required so that the effective area of the electrode foil is not reduced and the capacitance is not reduced. As countermeasures, for example, as described in Patent Document 1, an anode foil having a notch at one corner, a separator having a notch at two corners, and a notch at one corner. A cathode lead is connected to the exposed portion of the cathode foil corresponding to the notched portion of the anode foil in a state where the notched portion of the anode foil and the notched portion of the cathode foil are sequentially laminated so that the notched portion of the anode foil does not correspond to the cathode foil. There is one in which an anode lead is connected to the exposed portion of the anode foil corresponding to the notch portion of the foil.

Japanese Patent Application Laid-Open No. 5-234827

  However, in the above prior art, since the notches are provided at the corners of the anode foil, the cathode foil, and the separator, the strength against pressure applied in the capacitor stacking direction (thickness direction) must be weakened. For this reason, the burden on the lead connection part of electrode foil becomes large, and the connection failure of a lead may generate | occur | produce depending on the case.

  An object of the present invention is to provide a multilayer electrolytic capacitor that can increase the strength against pressure applied in the stacking direction while ensuring an effective area of the electrode foil.

  The present invention relates to an electrode laminate in which anode foil and cathode foil are alternately laminated via a separator, an anode lead connected to the anode foil, and a laminate type including a cathode lead connected to the cathode foil. In the electrolytic capacitor, the anode foil has a first lead connection portion to which the anode lead is connected and fixed, and a first cutout portion provided on a side different from the first lead connection portion. A second lead connection portion provided at a position corresponding to the first notch portion, to which the cathode lead is connected and fixed, and a second notch portion provided at a position corresponding to the first lead connection portion; The notch is formed so as to avoid the corner of the anode foil, and the second notch is formed so as to avoid the corner of the cathode foil.

  As described above, in the multilayer electrolytic capacitor of the present invention, the first notch is provided at a position corresponding to the second lead connection portion of the cathode foil in the anode foil, and corresponds to the first lead connection portion of the anode foil in the cathode foil. By providing the second cutout portion at the position, the first lead connection portion side and first cutout portion side regions of the anode foil and the second lead connection portion side and second cutout side regions of the cathode foil are effectively utilized. Thus, sufficient effective areas of the anode foil and the cathode foil can be secured. In addition, since the first notch is formed so as to avoid the corner of the anode foil and the second notch is formed so as to avoid the corner of the cathode foil, the anode foil and the cathode foil are pressure applied in the stacking direction. Are received from three directions with respect to the first cutout portion and the second cutout portion. Thereby, the intensity | strength with respect to the pressure concerning a lamination direction can be made high.

  Preferably, the anode foil and the cathode foil have a substantially rectangular shape, the first notch is formed at the center of one edge of the anode foil, and the second notch is one edge of the anode foil in the cathode foil. It is formed in the center position of the edge corresponding to the edge different from the part. In this case, variation in holding strength of the anode lead and the cathode lead due to the electrode laminate can be reduced.

  Preferably, the anode foil and the cathode foil have a substantially rectangular shape, the first notch is formed at one edge of the anode foil, and the second notch is one edge of the anode foil in the cathode foil. And is formed on an edge corresponding to the edge facing. In this case, the strength against pressure applied in the stacking direction can be further increased.

  ADVANTAGE OF THE INVENTION According to this invention, the intensity | strength with respect to the pressure concerning a lamination direction can be made high, ensuring the effective area of electrode foil. As a result, a desired capacitor capacity can be ensured, and the burden on the lead connection portion of the electrode foil can be reduced.

1 is a schematic perspective view showing an appearance of an embodiment of a multilayer electrolytic capacitor according to the present invention. It is a schematic perspective view which shows the electrode laminated body and lead | read | reed which were shown in FIG. FIG. 3 is an exploded perspective view showing an electrode laminate and a lead shown in FIG. 2. It is a figure which shows the cross-sectional structure of the anode foil shown in FIG. It is a schematic perspective view which shows the laminated structure of the anode foil, cathode foil, and separator which were shown in FIG. FIG. 3 is an exploded perspective view showing a laminated structure of an anode foil, a cathode foil and a separator shown in FIG. 2 together with leads. It is a figure which shows the manufacturing process of the multilayer electrolytic capacitor shown in FIG. It is a figure which shows the arrangement | positioning relationship between the anode foil and cathode foil shown in FIG. 2, and a case, and the arrangement | positioning relationship between the anode foil and cathode foil as a comparative example, and a case. It is a schematic perspective view which shows the laminated structure of the anode foil as another comparative example, a cathode foil, and a separator. It is a perspective view which shows the modification of the notch part shown in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a multilayer electrolytic capacitor according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic perspective view showing an appearance of an embodiment of a multilayer electrolytic capacitor according to the present invention, and FIG. 2 is a schematic perspective view showing a main part of the multilayer electrolytic capacitor shown in FIG. In each of the drawings, the multilayer electrolytic capacitor 1 of the present embodiment includes an electrode laminate 2 and a case 3 that accommodates the electrode laminate 2 together with an electrolytic solution (not shown).

  As shown in FIGS. 2 and 3, the electrode laminate 2 includes a plurality of anode foils 4 and cathode foils 5 that are electrode foils, and a plurality of separators 6. The electrode laminate 2 is configured by alternately laminating anode foils 4 and cathode foils 5 with separators 6 interposed therebetween.

  The anode foil 4 is made of a foil-like valve metal. Here, an aluminum foil (for example, a thickness of 50 to 150 μm) is used as the anode foil 4. As shown in FIG. 4, the anode foil 4 has an etching layer 7 formed by an etching process and an oxide film layer 8 formed on the etching layer 7. The cathode foil 5 is made of a metal etching foil in which an etching layer is formed on a metal plain foil. Here, an aluminum etching foil (for example, a thickness of 10 to 100 μm) is used as the cathode foil 5.

  The anode foil 4 and the cathode foil 5 have a substantially rectangular shape. As shown in FIGS. 3 and 5, a lead connection portion 9 is provided at one central position of the two opposing edges of the anode foil 4, and the other central position of the two opposing edges of the anode foil 4. Is provided with a rectangular cutout 10. A lead connection portion 11 is provided at one central position of two opposing edges of the cathode foil 5, and a rectangular notch 12 is provided at the other central position of the two opposing edges of the cathode foil 5. It has been. The dimensions of the notches 10 and 12 are equal.

  The separator 6 is made of insulating paper, fiber nonwoven fabric, or the like. The separator 6 has a function of electrically insulating the anode foil 4 and the cathode foil 5 and impregnating and holding an electrolytic solution (not shown). The separator 6 has a substantially rectangular shape. As shown in FIGS. 3 and 5, a rectangular notch 13 is provided at the center position of the two opposing edges of the separator 6. The dimensions of the notch 13 are equal to the dimensions of the notches 10 and 12.

  As shown in FIGS. 5 and 6, the electrode laminate 2 corresponds to the lead connecting portion 9 of the anode foil 4 and the notch 12 of the cathode foil 5, and the notch 10 of the anode foil 4 and the lead of the cathode foil 5. The anode foil 4 and the cathode foil 5 are alternately stacked via the separator 6 so that the connection portion 11 corresponds to each other and each notch portion 13 of the separator 6 corresponds to the notches 10 and 11. Thereby, the surface (lead connection portion 9) of each anode foil 4 is exposed on one side of the electrode laminate 2, and the surface (lead connection portion 11) of each cathode foil 5 on the other end side of the electrode laminate 2. Will be exposed.

  The case 3 is made of a flexible film (for example, a composite packaging film). The case 3 can be produced, for example, by superposing films having a rectangular shape and heat-sealing (heat-sealing) edges of the superposed films. The electrode laminate 2 and the electrolyte (not shown) are accommodated in the case 3 (a space formed by a partial region of the film that is not heat-sealed).

  The multilayer electrolytic capacitor 1 further includes an anode lead 14 connected to each anode foil 4 and a cathode lead 15 connected to each cathode foil 5, as shown in FIGS. These leads 14 and 15 are made of metal plane foil. Here, aluminum foil is used for the leads 14 and 15.

  The anode lead 14 has a zigzag shape that is bent so as to be connected and fixed to the lead connection portion 9 of each anode foil 4. At this time, the notch 12 is provided in the cathode foil 5, and the notch 13 is provided in the separator 6, so that a space for folding the anode lead 14 is secured. The anode lead 14 is joined to the lead connection portion 9 by, for example, caulking, Cold Weld, or laser welding in a state where the anode lead 14 is in contact with the lead connection portion 9 of each anode foil 4. As a result, the anode lead 14 and the anode foil 4 are electrically and physically connected.

  The cathode lead 15 has a zigzag shape that is bent so as to be connected and fixed to the lead connection portion 11 of each cathode foil 5. At this time, the notch 10 is provided in the anode foil 4 and the notch 13 is provided in the separator 6, so that a space for folding the cathode lead 15 is secured. The cathode lead 15 is joined to the lead connecting portion 11 by, for example, caulking, Cold Weld, or laser welding in a state where the cathode lead 15 is in contact with the lead connecting portion 11 of each cathode foil 5. Thereby, the cathode lead 15 and the cathode foil 5 are electrically and physically connected.

  Next, a method for manufacturing the multilayer electrolytic capacitor 1 will be described. First, as shown in FIG. 7, an anode foil base material 16 to be the anode foil 4 is prepared. The anode foil base material 16 is made of a large-sized aluminum foil. An etching layer and an oxide film layer are formed in advance on both surfaces of the anode foil base material 16 by etching and anodizing treatment (chemical conversion treatment). Subsequently, a plurality of anode foils 4 are formed by punching the anode foil base material 16 with a mold.

  Also, a cathode foil base material (not shown) to be the cathode foil 5 is prepared. The cathode foil base material is made of a large-sized aluminum etching foil. Then, similarly to the formation of the anode foil 4, a plurality of cathode foils 5 are formed by punching the cathode foil base material with a mold.

  Next, the separator 6 is prepared. Subsequently, the anode foil 4 and the cathode foil 5 are alternately laminated via the separator 6 as shown in FIGS. 3 and 5. Thereby, the electrode laminated body 2 will be obtained.

  Next, the lead connecting portion 9 of each anode foil 4 and the anode lead 14 are connected by caulking, Cold Weld or YAG laser welding, and the lead connecting portion 11 of each cathode foil 5 and the cathode lead 15 are caulking, Cold Weld or YAG. Connect by laser welding. Specifically, the anode lead 14 is brought into contact with the lead connection portion 9 of the anode foil 4 and is fixed by caulking from the anode lead 14 side, whereby the anode lead 14 and the lead connection portion 9 are joined. Further, the cathode lead 15 is brought into contact with the lead connection portion 11 of the cathode foil 5 and is fixed by caulking from the cathode lead 15 side, whereby the cathode lead 15 and the lead connection portion 11 are joined. Thereby, each anode foil 4 is connected in parallel to the anode lead 14, and each cathode foil 5 is connected in parallel to the cathode lead 15.

  Next, the electrode laminate 2 assembled with the leads 14 and 15 is accommodated in the case 3. The case 3 heats a portion other than the opening for inserting the electrode laminate 2 in the edge portion (seal portion) of the above-described film by a desired seal width under a predetermined heating condition using, for example, a sealing machine. Obtained by sealing. Then, after the electrode laminate 2 assembled with the leads 14 and 15 is accommodated in the case 3, an electrolytic solution is injected into the case 3. At this time, the electrode laminate 2 may be impregnated with an electrolytic solution. Subsequently, the opening of the case 3 is sealed using a vacuum sealer.

  Next, an aging process is performed. Here, the anode lead 14 is connected to the anode of the DC power source and the cathode lead 15 is connected to the cathode of the DC power source, and a DC voltage is applied between the anode foil 4 and the cathode foil 5. As a result, the damaged portion of the oxide film layer 8 of the anode foil 4 is repaired, and the oxide film layer is formed on the cut surface by punching the anode foil 4. Thus, the multilayer electrolytic capacitor 1 shown in FIG. 1 is obtained.

  By the way, the electrode laminated body 2 is accommodated in the case 3 as described above. At this time, as shown in FIG. 8A, the anode lead 14 is connected to the protrusion 51 provided on the anode foil 4 and the cathode lead 15 is connected to the protrusion 52 provided on the cathode foil 5. In the structure, since the protrusions 51 and 52 are present, the effective areas of the anode foil 4 and the cathode foil 5 are reduced, and as a result, the capacitor capacity is reduced.

  On the other hand, in this embodiment, the notch 10 is formed on one edge of the anode foil 4, the notch 12 is formed on one edge of the cathode foil 5, and the notch 13 is formed on both sides of the separator 6. In the state where the anode foil 4 and the cathode foil 5 are alternately laminated via the separator 6 so that the notches 10 and 12 are located on the opposite sides, the edge on the opposite side of the notch 10 in the anode foil 4 The anode lead 14 is connected to the (lead connecting portion 9), and the cathode lead 15 is connected to the edge (lead connecting portion 11) on the cathode foil 5 opposite to the notch 12. For this reason, as shown in FIG. 8B, when using the case 3 of the same size, the effective areas of the anode foil 4 and the cathode foil 5 are increased, and the anode foil 4 and the cathode foil 5 are compared with the case 3. Can be used effectively in space. Thereby, compared with what is shown to Fig.8 (a), a capacitor | condenser capacity can be increased.

  As shown in FIG. 9, in the structure in which the notch 53 is formed at one corner of the anode foil 4 and the cathode foil 5 and the notch 54 is formed at both corners of the separator 6, the electrode laminate 2 is laminated. When pressure from the direction (thickness direction) is applied, the pressure can be supported only from two directions with respect to the notches 53 and 54. For this reason, since the intensity | strength with respect to the pressure from the lamination direction of the electrode laminated body 2 becomes weak, the burden concerning the lead connection part of the anode foil 4 and the cathode foil 5 becomes large, and the connection defect of the leads 14 and 15 may arise. .

  On the other hand, in this embodiment, the notch 10 is formed in the anode foil 4 so as to avoid the corner of the anode foil 4, and the notch 12 is formed in the cathode foil 5 so as to avoid the corner of the cathode foil 5, Since the notch 13 is formed in the separator 6 so as to avoid the corner of the separator 6, the pressure applied to the electrode stack 2 in the stacking direction is supported from three directions with respect to the notches 10, 12, and 13. Become. As a result, compared to the structure shown in FIG. 9, the strength against the pressure in the stacking direction of the electrode laminate 2 is increased, so that the burden on the lead connection portion 9 of the anode foil 4 and the lead connection portion 11 of the cathode foil 5 is reduced. As a result, the occurrence of poor connection between the leads 14 and 15 can be suppressed. As a result, it is possible to improve the yield at the time of manufacture and to prevent the electrode laminate 2 from being damaged during use.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the rectangular notches 10, 12, and 13 are formed in the anode foil 4, the cathode foil 5, and the separator 6, respectively. As the shapes of these notches 10, 12, and 13, In particular, the shape is not limited to a rectangular shape, and may be a substantially semicircular shape as shown in FIG. By making the shape of the notches 10, 12, 13 into a substantially semicircular shape, the strength against pressure from the stacking direction of the electrode stack 2 is further increased.

  Moreover, in the said embodiment, although the notch parts 10 and 12 were formed in the center position of the one edge part of the anode foil 4 and the cathode foil 5, these notch parts 10 and 12 are the corners of the anode foil 4 and the cathode foil 5. It may be formed so as to avoid the portion.

  Furthermore, in the above embodiment, the anode lead 14 and the cathode lead 15 are connected to the anode foil 4 and the cathode foil 5 so as to extend on the opposite sides of the electrode laminate 2, respectively. It is also possible to adopt a structure in which the leads 15 are connected to the anode foil 4 and the cathode foil 5 respectively so as to extend in directions perpendicular to the electrode laminate 2. In this case, the lead connection portion 9 and the notch portion 10 of the anode foil 4 are provided at the adjacent edges of the anode foil 4, and the lead connection portion 11 and the notch portion 12 of the cathode foil 5 are adjacent to each other of the cathode foil 5. It will be provided at the matching edge.

  Moreover, in the said embodiment, although the notch part 13 was formed in the both-sides edge part of the separator 6, without forming the notch part 13 in the side corresponding to the lead connection part 10 of the anode foil 4 in the separator 6. FIG. The lead connection part 10 may be covered with the separator 6. When the anode lead 14 is connected to the surface of the anode foil 4, the oxide film layer 8 on the surface of the anode foil 4 is destroyed. Therefore, it is necessary to repair the anode lead 14 using an electrolytic solution by aging treatment. By covering the connection part 10 with the separator 6, the electrolyte impregnated in the separator 6 is sufficiently supplied to the lead connection part 10. Similarly, the lead connection portion 11 may be covered with the separator 6 without forming the notch portion 12 on the side of the separator 6 corresponding to the lead connection portion 11 of the cathode foil 5.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

Example 1
First, an anode foil base material on which an etching layer and an oxide film layer were formed was punched out so as to have a size of 17 mm × 32 mm, thereby obtaining an anode foil in which a notch was formed at the center of one edge. Moreover, the cathode foil base material was similarly punched out so as to have a size of 17 mm × 32 mm, and a cathode foil having a notch formed at the center position of one edge portion was obtained. Further, a separator having a notch formed at the center position of both side edge portions was prepared. Thereafter, the anode foil and the cathode foil were alternately laminated through the separator so that the notched portion of the anode foil and the notched portion of the cathode foil were positioned on the opposite sides, thereby obtaining an electrode laminate. Here, the anode foil has 5 layers, the cathode foil has 6 layers, and the separator has 12 layers.

  Also, an anode lead made of aluminum foil was prepared, the anode lead was brought into contact with the surface of each anode foil, and fixed by caulking from the anode lead side, thereby joining the anode lead and each anode foil. Also, a cathode lead made of aluminum foil was prepared, the cathode lead was brought into contact with the surface of each cathode foil, and fixed by caulking from the cathode lead side, thereby joining the cathode lead and each cathode foil.

  Moreover, after preparing two aluminum laminate foil used as a case and arrange | positioning an electrode laminated body between aluminum laminate foil, three sides of the aluminum laminate foil were sealed by heat sealing. Thereafter, an electrolytic solution was poured, and the remaining one side of the aluminum laminate foil was sealed by heat sealing. And the aging process was performed and the multilayer type electrolytic capacitor was produced.

(Comparative Example 1)
Multilayer electrolysis was performed in the same manner as in Example 1 except that anode foil and cathode foil were used in which notched portions were formed at one corner, and separators were used in which notched portions were formed on both corners. A capacitor was produced.

(Characteristic evaluation test of multilayer electrolytic capacitor)
100 multilayer electrolytic capacitors of Example 1 and Comparative Example 1 were produced, and aging treatment was performed on each of the 100 multilayer electrolytic capacitors to confirm capacitor characteristics and to evaluate yield (capacitance). As the yield, open defects (disconnection of connected leads) indicating weakness against pressure in the thickness direction were evaluated. At this time, a product having a yield (capacity) of 90% or more was determined to be OK. The results are shown in Table 1.

  In Example 1, the yield was improved as compared with Comparative Example 1. In Example 1, it is presumed that by providing a notch at the center of one edge of the anode foil and the cathode foil, the strength against the pressure in the thickness direction is increased, and open defects are reduced.

DESCRIPTION OF SYMBOLS 1 ... Multilayer electrolytic capacitor, 2 ... Electrode laminated body, 4 ... Anode foil, 5 ... Cathode foil, 6 ... Separator, 9 ... Lead connection part (1st lead connection part), 10 ... Notch part (1st notch part) , 11 ... lead connection part (second lead connection part), 12 ... notch part (second notch part), 14 ... anode lead, 15 ... cathode lead.

Claims (3)

A multilayer electrolytic capacitor comprising an electrode laminate in which anode foil and cathode foil are alternately laminated via a separator, an anode lead connected to the anode foil, and a cathode lead connected to the cathode foil Because
The anode foil has a first lead connection portion to which the anode lead is connected and fixed, and a first cutout portion provided on a different side from the first lead connection portion,
The cathode foil is provided at a position corresponding to the first notch, and a second lead connecting part to which the cathode lead is connected and fixed, and a second notch provided at a position corresponding to the first lead connecting part. And
The first cutout is formed to avoid a corner of the anode foil,
The multilayer electrolytic capacitor, wherein the second notch is formed so as to avoid a corner of the cathode foil. The anode foil and the cathode foil have a substantially rectangular shape,
The first notch is formed at the center position of one edge of the anode foil,
2. The multilayer electrolytic capacitor according to claim 1, wherein the second notch is formed at a center position of an edge corresponding to an edge different from the one edge of the anode foil in the cathode foil. . The anode foil and the cathode foil have a substantially rectangular shape,
The first notch is formed at one edge of the anode foil,
2. The multilayer electrolytic capacitor according to claim 1, wherein the second notch is formed at an edge corresponding to an edge of the cathode foil facing the one edge of the anode foil.

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