JP6531134B2 - Lead wire terminal for electrolytic capacitor, method of manufacturing lead wire terminal for electrolytic capacitor, and electrolytic capacitor - Google Patents

Description

  The present invention relates to a lead wire terminal for an electrolytic capacitor, a method of manufacturing a lead wire terminal for an electrolytic capacitor, and an electrolytic capacitor.

  As well known, a lead wire terminal for an electrolytic capacitor is provided with a tab terminal formed of a metal rod such as aluminum and a lead wire connected to one end thereof.

  A conversion coating is formed on the outer surface of the metal rod of the tab terminal material by chemical conversion treatment in order to suppress current leakage.

  The tab terminal has a rod-like portion at one end and a flat portion at the other end.

  The flat portion is formed by pressing a part of the metal rod into a flat plate shape, but at that time, a crack may occur in the chemical conversion film.

  Therefore, the tab terminal is dipped in a chemical conversion solution to perform secondary chemical conversion treatment, thereby repairing the cracks in the chemical conversion film.

  At that time, if a chemical solution adheres to the connection between the tab terminal and the lead wire, or the lead wire, the connection etc. may be corroded, so a region separated from the rod portion in the flat portion in the axial direction by a predetermined length or more The secondary chemical conversion treatment is applied only to (hereinafter referred to as “secondary chemical conversion region”).

Japanese Patent Application Laid-Open No. 6-97012

  A region between the secondary chemical conversion region in the flat portion and the rod-like portion (hereinafter, referred to as "intermediate region") is a portion where plastic deformation due to press processing is large, and therefore a crack is likely to occur especially in the chemical conversion film.

  Although the secondary conversion treatment is not performed in this intermediate region, in the case where the electrolyte of the capacitor element is a liquid, cracks generated in the chemical conversion film are often repaired by the electrolyte.

  However, when the electrolyte is solid, the crack is difficult to be repaired, and the current leaks from the crack, which causes the yield of the electrolytic capacitor to decrease.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a lead wire terminal for an electrolytic capacitor capable of suppressing a leakage current due to a crack of a chemical conversion film to improve a yield rate of an electrolytic capacitor. It is to provide.

In order to achieve the above object, a first invention is a lead terminal for an electrolytic capacitor, wherein the tab terminal is formed by pressing a metal bar whose outer surface is coated with a first conversion coating, And a lead wire connected to one end of the tab terminal, the tab terminal having a rod portion at one end and a flat portion at the other end, the axial direction from the rod at the flat portion The second chemical conversion film covering the outer surface is formed only in the secondary chemical conversion region separated by a predetermined length or more , and the outer surface of the intermediate region between the rod portion in the flat portion and the secondary chemical conversion region is It is covered with an insulating resin film.

The second invention is a method of manufacturing a lead wire terminal for an electrolytic capacitor, including a tab terminal having a rod-like portion at one end and a flat portion at the other end, and a lead wire connected to one end of the tab terminal. A method of preparing a metal rod whose outer surface is coated with a first chemical conversion film, pressing the metal rod to form the tab terminal, and having a predetermined length in the axial direction from the rod portion in the flat portion A second chemical conversion film for covering the outer surface is formed only in the secondary formation region separated by a large distance , and the outer surface of the intermediate region between the rod portion in the flat part and the secondary formation region is insulated. Coat with a coating.

  The third invention is formed by winding an anode foil to which a lead wire terminal is attached and a cathode foil to which a lead wire terminal is attached, with a separator interposed therebetween. It is an electrolytic capacitor provided with a capacitor | condenser element, Comprising: At least one is comprised with the lead wire terminal of 1st invention among the lead wire terminal by the side of the said anode foil, and the lead wire terminal by the side of the said cathode foil.

  ADVANTAGE OF THE INVENTION According to this invention, the leakage current resulting from the crack of a chemical conversion film can be suppressed, and the yield rate of an electrolytic capacitor can be improved.

1 is a perspective view of a lead wire terminal according to the present invention. It is an enlarged plan view of the tab terminal of the lead terminal of FIG. It is a perspective view of the capacitor | condenser element of the electrolytic capacitor by this invention. 1 is a longitudinal sectional view of an electrolytic capacitor according to the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the lead wire terminal 1 includes a tab terminal 10 formed of a metal rod made of aluminum or the like and a lead wire 20 connected to one end thereof.

  The metal rod is previously subjected to a chemical conversion treatment, and the outer surface is coated with a chemical conversion film (hereinafter, this chemical conversion film is referred to as "first chemical conversion film").

  The tab terminal 10 is formed by pressing the metal rod, and has a rod-like portion 11 on one end side and a flat portion 12 on the other end side.

  In FIG. 2, the hatching of the solid line applied to the outer peripheral surface of the rod-like portion 11 represents the first chemical conversion film.

  The lead wire 20 is connected to one end of the rod-like portion 11 by welding or the like. The lead wire 20 is formed of, for example, a CP wire in which a copper layer is provided on the outer peripheral surface of an iron wire.

  The flat portion 12 is formed by pressing a part of the metal rod into a flat plate shape and cutting the outer periphery along the thickness direction. The lead wire 20 may be connected after the flat portion 12 is formed by pressing a metal rod.

  The outer surface of a region (hereinafter, this region is referred to as a “secondary formation region”) 121 spaced a predetermined length L1 or more from the rod-like portion 11 in the flat portion 12 in the axial direction is a chemical conversion film (hereinafter, this chemical conversion film Referred to as "second chemical conversion film". In FIG. 2, the hatching of the broken line represents the second chemical conversion film, and the first chemical conversion film is formed thereunder (back side).

  In the present embodiment, a reinforcing rib 13 extending between the rod-like portion 11 and the flat portion 12 is formed.

  The reinforcing rib 13 is formed between an end face on the flat portion 12 side of the rod-like portion 11 and one surface of the flat portion 12 and has a substantially semicircular shape in plan view.

  The reinforcing rib 13 is formed in a region 122 between the rod-like portion 11 and the secondary formation region 121 in the flat portion 12 (hereinafter, this region is referred to as an “intermediate region”).

  The outer surface of the intermediate region 122 is coated with an insulating resin film. In FIG. 2, grid-like hatching represents the insulating resin film, and the first chemical conversion film is formed thereunder (on the back side).

  The insulating resin film is formed, for example, by applying a solution of a thermosetting insulating resin to the intermediate region 122 with a known dispenser and heating and curing with a heating device, but it is formed by other methods. You can also

  In the present embodiment, the material of the insulating resin film is a thermosetting acrylic resin, but other materials can also be used. For example, an epoxy resin, a silicone resin, an acrylic resin, a phenol resin, a fluorine resin, a urea resin, etc. may be used, and a UV curable resin may be used.

  Although the film thickness of the insulating resin film of the present embodiment is 30 μm, it is not particularly limited as long as it is a film thickness that can effectively suppress the leakage current by covering the reinforcing rib 13. For example, the film thickness can be set in the range of 0.1 to 100 μm, and more preferably in the range of 10 to 50 μm.

  In addition, the length L1 (length along the axial direction of the rod portion 11) of the intermediate region 122 covered with the insulating resin film takes the entire length in the same direction of the flat portion 12 in consideration of manufacturing cost and productivity. When L2 is set, it is preferable to set L1 ≦ L2 / 3.

  The electrolytic capacitor according to the present invention is manufactured by the following procedure.

  First, a plurality of metal rods whose outer surfaces are coated with the first conversion coating are prepared.

  Next, the metal rod is pressed to form the tab terminal 10.

  Next, the outer surface of the secondary chemical conversion region 121 of the tab terminal 10 is coated with a second chemical conversion film.

  Then, the outer surface of the intermediate region 122 is covered with an insulating resin film.

  The lead wire terminal 1 manufactured in this manner is attached to the anode foil and the cathode foil which are materials of the capacitor element, and as shown in FIG. 3, the anode foil 41 and the cathode foil 42 are interposed between them. The capacitor element 40 is formed by winding with the separator 43 interposed. Then, a solid electrolyte layer (not shown) is formed between the anode foil 41 and the cathode foil 42 by a known method.

  The pair of lead wires 20 protruding from the end face of the capacitor element 40 is inserted into either of the pair of through holes 51 formed in the sealing body 50 (see FIG. 4), and the capacitor element 40 and the sealing body 50 are cylindrical When the sealing body 50 is fixed to the opening end of the outer case 60, the opening end of the outer case 60 is sealed with the sealing body 50.

  Further, a cylindrical shrink film (not shown) in which a product name, a manufacturer name and the like are described is fitted to the outer periphery of the outer case 60, and the shrink film is thermally shrunk to complete the electrolytic capacitor 100.

  In the lead wire terminal 1 of the present invention, since the intermediate region 122 is covered with the insulating resin film, even if a crack is generated in the first chemical conversion film of the intermediate region 122 at the time of pressing the tab terminal 10 Can be suppressed to improve the yield rate of the electrolytic capacitor.

  In particular, when the lead wire terminal 1 of the present invention is used for an electrolytic capacitor in which the electrolyte is solid, the yield rate is remarkably improved as compared with the case where the conventional lead wire terminal is used.

  In the present embodiment, the outer periphery of the rod-shaped portion 11 is not covered with the insulating resin film. Since the rod-shaped portion 11 is inserted into the through hole 51 of the sealing body 50, when the rod-shaped portion 11 is covered with the insulating resin film, it is necessary to control the thickness of the insulating resin film.

  That is, when the thickness of the insulating resin film is too large, insertion into the through hole 51 is difficult, and conversely, when the thickness of the insulating resin film is too small, a gap is generated between the insulating resin film and the through hole 51. This is because there is a possibility that the electrolyte may leak.

  When the outer periphery of the rod-shaped portion 11 is not covered with the insulating resin film, the management of the thickness of the insulating resin film is not necessary, and the productivity is improved.

  The present invention is not limited to the above embodiment.

  For example, in the above embodiment, the insulating resin film is formed on both of the lead wire terminal on the anode foil side and the lead wire terminal on the cathode foil side, but the insulating resin film is formed on only one of the lead terminals. May be formed.

  In addition, an insulating resin film may be formed on the outer peripheral surface of the rod-like portion (the region hatched with the solid line in FIG. 2). In this case, the occurrence of leakage current from the rod-like portion is also reduced, so that the yield rate is further improved.

  Further, the shape and number of reinforcing ribs are not limited to those shown in the above embodiment.

  The present invention can also be applied to a lead wire terminal not having a reinforcing rib.

  The present invention can also be applied to electrolytic capacitors in which the electrolyte is a liquid, and can also be applied to hybrid electrolytic capacitors in which the electrolyte consists of a liquid and a solid.

  Besides the above, various modifications can be made to the above embodiment without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Lead wire terminal 10 Tab terminal 11 Rod part 12 Flat part 121 Secondary formation area 122 Intermediate region 13 Reinforcement rib 20 Lead wire 40 Capacitor element 41 Anode foil 42 Cathode foil 43 Separator 50 Sealing body 60 Exterior case 100 Electrolytic capacitor

Claims (7)

A tab terminal (10) formed by pressing a metal bar whose outer surface is coated with a first conversion coating,
A lead wire (20) connected to one end of the tab terminal (10);
The tab terminal (10) has a rod-like portion (11) on one end side and a flat portion (12) on the other end side,
A second chemical conversion film for covering the outer surface is formed only on the secondary chemical conversion region (121) separated from the rod-like portion (11) in the flat portion (12) in the axial direction by a predetermined length or more .
A lead for an electrolytic capacitor, wherein the outer surface of an intermediate region (122) between the rod-like portion (11) and the secondary chemical conversion region (121) in the flat portion (12) is covered with an insulating resin film Terminal.   The lead wire terminal for electrolytic capacitors according to claim 1, wherein a reinforcing rib (13) straddling between the rod-like portion (11) and the flat portion (12) is formed in the intermediate region (122).   The electrolytic capacitor according to claim 1, wherein an outer periphery of the rod-like portion (11) is not covered with the insulating resin film. An electrolysis comprising a tab terminal (10) having a rod-like portion (11) on one end side and a flat portion (12) on the other end side, and a lead wire (20) connected to one end of the tab terminal (10). It is a manufacturing method of lead wire terminal (1) for capacitors, and
Prepare a metal rod whose outer surface is coated with the first conversion coating,
Pressing the metal rod to form the tab terminal (10);
A second chemical conversion film for covering the outer surface is formed only on the secondary chemical conversion region (121) separated from the rod-like portion (11) in the flat portion (12) in the axial direction by a predetermined length or more.
A lead wire terminal for an electrolytic capacitor, the outer surface of an intermediate region (122) between the rod-like portion (11) and the secondary formation region (121) in the flat portion (12) being covered with an insulating resin film Production method. Formed by winding an anode foil (41) to which a lead wire terminal is attached and a cathode foil (42) to which a lead wire terminal is attached, with a separator (43) interposed therebetween An electrolytic capacitor (100) comprising the capacitor element (40),
An electrolytic capacitor in which at least one of the lead wire terminal on the anode foil (41) side and the lead wire terminal on the cathode foil (42) side is constituted by the lead wire terminal according to any one of claims 1 to 3. . The electrolytic capacitor according to claim 5 , wherein a solid electrolyte layer is formed between the anode foil (41) and the cathode foil (42). A bottomed cylindrical outer case (60) for housing the capacitor element (40); and a sealing body (50) fixed to the open end of the outer case (60),
The sealing body (50) has a through hole (51) into which the rod-like portion (11) is inserted,
The electrolytic capacitor according to claim 5 or 6, wherein the outer periphery of the rod-like portion (11) is not covered with the insulating resin film.

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