JP2011003698A - Method of manufacturing solid electrolytic capacitor and solid electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a solid electrolytic capacitor which is constructed by forming a solid electrolyte of conductive polymers in a foil wound capacitor element into a low-profile and surface mountable chip component.SOLUTION: The foil wound capacitor element which is formed by winding anode electrode foil and cathode foil both connected with lead terminals through separators is flattened into an oblong or elliptical shape to form a flattened capacitor element. Then, the solid electrolyte including the conductive polymers is formed in the flattened capacitor element and the flattened capacitor element in which the solid electrolyte is formed, is housed in a housing formed of a flat box the top of which is open and which has lead insertion holes in a side face. The ends of the lead terminals are drawn out from the lead insertion holes and a hardenable resin is put into the housing from its top opening for filling the housing and fixing the flattened capacitor element in the housing. The ends of the lead terminals are bent in a predetermined direction. In this manner, the low-profile and surface mountable chip component is formed.

Description

  The present invention relates to a method for manufacturing a solid electrolytic capacitor in which a solid electrolytic capacitor in which a solid electrolyte made of a conductive polymer is formed on a foil wound capacitor element is used as a chip component that can be surface-mounted with a low profile.

  Solid electrolytic capacitors use a solid electrolyte made of a conductive polymer as the electrolyte, so there is almost no problem such as liquid leakage or transpiration, which has been pointed out in aluminum electrolytic capacitors impregnated with electrolytic solution, and long life. In addition, in recent years, it has been rapidly spread because of its low ESR.

  An aluminum solid electrolytic capacitor using a foil-wound capacitor element is manufactured through almost the same process as an aluminum electrolytic capacitor except for an electrolyte forming process.

  That is, instead of impregnating with an electrolyte solution, a solid electrolyte made of a conductive polymer is used instead of impregnation of an electrolytic solution on a capacitor element in which an anode foil and a cathode foil made of aluminum each having a tab terminal connected thereto are spirally wound through a separator. Formed and housed in a bottomed cylindrical aluminum case as an exterior body, its opening is sealed with sealing rubber, the edge of the opening is caulked, and it is laterally drawn on the case peripheral surface corresponding to the sealing rubber It is produced by engraving a groove.

  Therefore, the appearance is almost the same as the aluminum electrolytic capacitor described in Patent Document 1, for example.

  However, since the opening of the aluminum case is sealed with the sealing rubber, there is a problem that the height (total axial length) of the sealing rubber is higher than that of other chip components.

  If the thickness of the sealing rubber is reduced, it can be reduced in height, but on the other hand, it cannot withstand the pressure increase in the case due to heat during reflow soldering, and so-called reflow swelling is likely to occur. It is not preferable.

  If it is a foil laminated type, the height can be reduced, but this has another problem that it is necessary to newly introduce dedicated equipment and the production cost is increased.

JP 2008-108865 A

  Accordingly, an object of the present invention is to provide a method of manufacturing a solid electrolytic capacitor using a solid electrolytic capacitor formed by forming a conductive polymer solid electrolyte on a foil-wound capacitor element as a chip component that can be surface-mounted with a low profile. There is to do.

  In order to solve the above problems, a first invention of the present application is a solid electrolytic capacitor in which a solid electrolyte made of a conductive polymer is formed on a foil wound type capacitor element having an anode lead terminal and a cathode lead terminal. In the manufacturing method, the foil-wound capacitor element is flattened into an oval shape or an ellipse shape to obtain a flat capacitor element, and then a solid electrolyte containing a conductive polymer is formed on the flat capacitor element. The flat capacitor element in which the solid electrolyte is formed is housed in an outer package made of a flat box having a lead insertion hole corresponding to the anode lead terminal and the cathode lead terminal on a predetermined side surface. The lead end side of each of the anode lead terminal and the cathode lead terminal is pulled out from each lead insertion hole, and a curable resin is opened from the upper surface opening of the exterior body. To fix the flat capacitor element in the outer package, and bend the tip of each of the anode lead terminal and the cathode lead terminal in a predetermined direction to form a chip component that can be surface-mounted with a low profile. It is characterized by.

  Further, a second invention of the present application is the method for producing a solid electrolytic capacitor in which a solid electrolyte made of a conductive polymer is formed on a foil wound type capacitor element having an anode lead terminal and a cathode lead terminal. The foil-wound capacitor element is flattened into an oval or elliptical shape to form a flat capacitor element, and after forming a solid electrolyte containing a conductive polymer in the flat capacitor element, the anode lead terminal and the cathode A resin sheathing body made of a mold resin is formed directly around the flat capacitor element except for the respective tip end sides of the lead terminals, and the tip ends of the anode lead terminal and the cathode lead terminal are formed. The side is bent in a predetermined direction to form a chip component that can be surface-mounted with a low profile.

  In each of the above inventions, the foil wound type capacitor element may be of the same lead direction type or may be of the opposite lead type.

  The present invention also includes a solid electrolytic capacitor manufactured by the manufacturing method of each of the above inventions.

  According to the present invention, for example, a cylindrical foil wound capacitor element produced by an existing aluminum electrolytic capacitor facility is flattened into an oval shape or an elliptical shape to obtain a flat capacitor element, and then the conductive property is obtained. A solid electrolyte containing a polymer was formed, and the capacitor element having the flattened solid electrolyte was placed sideways, that is, the winding axis of the capacitor element was parallel to the substrate surface of the circuit board, and the capacitor element was matched to it. Low-profile surface mounting is possible by storing in a flat box-shaped outer package and fixing it with a curable resin, or by forming an outer package that is made of mold resin directly around the capacitor element. Chip components.

The perspective view which shows the anode electrode foil at the time of foil winding, a cathode electrode foil, and a separator. The schematic diagram which shows the state which crushes the capacitor | condenser element wound by the cylindrical shape flatly. The perspective view which shows the flat capacitor | condenser element in 1st Embodiment. The perspective view which shows the exterior body for the said flat capacitor elements. The perspective view which shows the state which accommodated the said flat capacitor element in the exterior body. The perspective view which shows the solid electrolytic capacitor by the said 1st Embodiment. The perspective view which shows the exterior body applied to 2nd Embodiment. The perspective view which shows the state which accommodated the said flat capacitor element in the exterior body. The perspective view which shows the solid electrolytic capacitor by the said 2nd Embodiment. The perspective view which shows another example of the flat capacitor | condenser element applied to 2nd Embodiment. Sectional drawing which shows the solid electrolytic capacitor by 3rd Embodiment typically.

  Next, some embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

  Since the solid electrolytic capacitor of the present invention uses a foil wound type capacitor element, first, as shown in FIG. 1a, the anode electrode foil 11 to which the tab terminal 15 is attached and the cathode electrode to which the tab terminal 16 is attached. By winding the foil 13 spirally through the separators 12 and 14, the cylindrical capacitor element 10 shown in FIG. 1b is produced.

  The anode electrode foil 11 is preferably an aluminum foil having a surface roughened by an etching process, and then an oxide film as a dielectric formed on the surface by, for example, an anodic oxidation method.

  On the other hand, the cathode electrode foil 13 is obtained by etching an aluminum foil or an alloy foil thereof roughened by etching, or an oxide film formed thereon, a valve metal foil or an alloy thereof in a plain state or by etching. It is possible to use a material in which particles such as carbon and titanium are attached to the surface by vapor deposition.

  Further, the tab terminals 15 and 16 have CP round wires (solder-plated copper coated steel wires) on the round bar side end surfaces of the flat-plate-shaped terminal bodies 15a and 16a which are flattened by pressing one end side of the aluminum round bar wire. A terminal formed by welding 15b and 16b may be used.

  In the following description, the CP line 15b of the anode-side tab terminal 15 may be referred to as “anode lead terminal 15b”, and the CP line 16b of the cathode-side tab terminal 16 may be referred to as “cathode lead terminal 16b”.

  Next, as shown in FIG. 1 b, the capacitor element 10 is placed on the horizontal base surface 110 of the press device, and the press head 120 is used to place the capacitor element 10 in a direction orthogonal to the winding axis (arrow A direction). The flat capacitor element 10A in the first embodiment shown in FIG. 1c is produced.

  The flat capacitor element 10A according to the first embodiment is a lead co-directional type (discrete type) in which the anode lead terminal 15b and the cathode lead terminal 16b are drawn from the same end face side of the foil wound body.

  When the capacitor element 10 is crushed flat, the corners of the terminal bodies 15a and 16a of the tab terminals 15 and 16 do not cause foil damage or foil breakage, as shown in FIG. The tab terminals 15 and 16 are present inside one of the two elements virtually divided around the diameter line R1 of the cylindrical capacitor element 10, and the diameter line R1 is parallel to the base surface 110. The cylindrical capacitor element 10 is preferably crushed from the direction orthogonal to the base surface 110.

  In FIG. 1c, for convenience of drawing, the flat capacitor element 10A has an oval shape, but when it is crushed by a press, it is actually an oval shape including a pair of parallel flat surfaces. Alternatively, the flat capacitor element 10A may be wound up in an elliptical shape, and this aspect is also included in the present invention.

  Preferably, the flat capacitor element 10A is immersed in a chemical conversion liquid mainly composed of, for example, ammonium adipate, and a predetermined voltage is applied to the anode electrode foil 11 via the tab terminal 15 to re-attach the anode electrode foil 11 again. Form. Thereby, the defect | deletion location of the oxide film of the anode electrode foil 11 produced at the time of foil winding and flattening is repaired.

  Thereafter, the flat capacitor element 10A is impregnated with a predetermined monomer (for example, thiophene monomer (3,4-ethylenedioxythiophene)) and an oxidizing agent, and chemically polymerized to form a solid electrolyte made of a conductive polymer.

  As described above, in the present invention, by forming a solid electrolyte on the flattened capacitor element 10A, a good solid electrolyte is maintained in the following steps.

  Next, in order to form an exterior body on the flat capacitor element 10A, in the first embodiment, as shown in FIG. 1d, the exterior body has an open upper surface, and the first side for the anode lead terminal 15b on the same side surface. A flat box body 20A made of a heat-resistant resin having a first lead insertion hole 21a and a second lead insertion hole 21b for the cathode lead terminal 16b is used.

  In this box 20A, as shown in FIG. 1e, the flat capacitor element 10A is accommodated horizontally, and the anode lead terminal 15b and the cathode lead terminal 16b are respectively connected to the first lead insertion hole 21a and the second lead insertion hole 21a. Pull out from the lead insertion hole 21b.

  Then, as shown in FIG. 1f, the curable resin 31 is filled from the upper surface opening of the box 20A and cured to fix the flat capacitor element 10A in the box 20A. The curable resin 31 may be either a thermosetting resin or an ultraviolet curable resin, but is preferably a thermosetting resin in order to uniformly cure the entire resin.

  Thereafter, the respective tip portions of the anode lead terminal 15b and the cathode lead terminal 16b are bent in a predetermined direction along a substrate surface of a circuit board (not shown) to obtain a solid electrolytic capacitor 1A that can be surface-mounted.

  In this example, as shown in FIG. 1f, the front end portions of the anode lead terminal 15b and the cathode lead terminal 16b are bent downward along the side surface of the box body 20A, and then formed into a plane including the bottom surface of the box body 20A. Although it is bent in the direction away from the box 20A along, it may be bent so as to sink into the bottom surface of the box 20A. In any case, it is preferable that the tip portions of the anode lead terminal 15b and the cathode lead terminal 16b are flattened with a press or the like.

  According to the solid electrolytic capacitor 1, since the flat capacitor element 1A formed by flatly crushing the foil wound capacitor element is used, the height can be reduced correspondingly. In addition, since the existing aluminum electrolytic capacitor manufacturing equipment can be used except for the step of forming the solid electrolyte, it is advantageous in terms of production cost.

  Next, a second embodiment of the present invention will be described with reference to FIGS. 2a to 2c. In this second embodiment, the flat capacitor element 10A of the same lead direction type shown in FIG. 1c is apparently a solid electrolytic capacitor formed into a chip of the opposite lead type.

  Therefore, as shown in FIG. 2a, the upper surface is opened as an exterior body for housing the flat capacitor element 10A, and the first lead insertion hole 21a for the anode lead terminal 15b and the first lead insertion for the cathode lead terminal 16b. A flat box 20B made of a heat-resistant resin drilled on the side surface facing the hole 21b is used.

  FIG. 2B shows a state in which the flat capacitor element 10A is horizontally placed and housed in the box 20B, and the lead terminals 15b and 16b are pulled out from the lead insertion holes 21a and 21b.

  In this case, one lead terminal is pulled out from a lead insertion hole formed in the opposite side surface, and the other lead terminal is lengthened and bent to the other end face side of the flat capacitor element 10A. In addition, the lead terminal is pulled out from a lead insertion hole formed in the opposite side surface. The one lead terminal is used as an anode lead terminal 15b, and the other lead terminal is used as a cathode lead terminal 16b. It is preferable.

  After the flat capacitor element 10A is accommodated in the box 20B as described above, as shown in FIG. 2c, the curable resin 31 is filled from the upper surface opening of the box 20B and cured to be flattened capacitor element 10A. Is fixed in the box 20B. The curable resin 31 may be either a thermosetting resin or an ultraviolet curable resin, but also in the second embodiment, a thermosetting resin is preferable in order to cure the entire resin evenly.

  After that, the tip portions of the anode lead terminal 15b and the cathode lead terminal 16b are bent in a predetermined direction along the substrate surface of a circuit board (not shown), thereby forming a chip-opposite lead type solid electrolytic capacitor that can be surface mounted. Obtain 1B.

  Also in the second embodiment, it is preferable that the tip portions of the anode lead terminal 15b and the cathode lead terminal 16b are bent in a predetermined direction as in the first embodiment and flattened by a press or the like.

  In order to obtain the chip-type solid electrolytic capacitor 1B of the opposite lead type shown in FIG. 2c, the flat capacitor element 10B of the opposite lead type shown in FIG. 3 can also be used.

  In FIG. 1 a, the flat capacitor element 10 </ b> B has, for example, a cathode-side tab terminal 16 attached in a direction opposite to the anode-side tab terminal 15, and the anode electrode foil 11 and the cathode electrode foil 13 are connected to the separators 12 and 14. After being wound in a spiral shape, it is produced by crushing flatly as shown in FIG. 1b.

  According to the flat capacitor element 10B of the opposite lead type, the anode lead terminal 15b and the cathode lead terminal 16b can be connected without routing one lead terminal in the box 20B as in the second embodiment. It can be directly pulled out from the corresponding lead insertion holes 21a and 21b.

  Next, a third embodiment of the present invention will be described with reference to FIG.

  In the third embodiment, a resin sheathing body 41 made of mold resin is directly formed around the flat capacitor element 10B of the opposite lead type shown in FIG. 3 along the flat shape, and the anode lead terminal 15b and the cathode Each tip end side of the lead terminal 16b is bent in a predetermined direction to obtain a solid electrolytic capacitor 1C in a chip shape that can be surface-mounted with a low profile.

  The resin sheathing body 41 may be formed by placing the flat capacitor element 10B of the opposite lead type into a molding die (not shown) and injecting a heat-resistant molten synthetic resin into the cavity.

  In FIG. 4, the tip end sides of the anode lead terminal 15 b and the cathode lead terminal 16 b are bent in the form of a foot so as to approach each other along the bottom surface of the resin sheath body 41. It may be bent in a direction away from each other in a plane including the bottom surface.

  In any case, it is preferable that the tip end sides of the anode lead terminal 15b and the cathode lead terminal 16b are flattened by pressing.

1A, 1B, 1C Solid electrolytic capacitor 10A, 10B Flat capacitor element 15b Anode lead terminal 16b Cathode lead terminal 20A, 20B Box 21a First lead insertion hole 21b First lead insertion hole 31 Curable resin 41 Resin exterior body

Claims (5)

In a method for producing a solid electrolytic capacitor in which a solid electrolyte made of a conductive polymer is formed on a foil wound type capacitor element having an anode lead terminal and a cathode lead terminal,
After flattening the foil-wound capacitor element into an oval or elliptical shape to form a flat capacitor element, a solid electrolyte containing a conductive polymer is formed on the flat capacitor element,
A flat capacitor element in which the solid electrolyte is formed is housed in an outer package made of a flat box having an open upper surface and a lead insertion hole corresponding to the anode lead terminal and the cathode lead terminal on a predetermined side surface. Along with, the leading end side of the anode lead terminal and the cathode lead terminal from the lead insertion hole,
A curable resin is filled from the opening on the top surface of the outer package to fix the flat capacitor element in the outer package, and the front ends of the anode lead terminal and the cathode lead terminal are bent in a predetermined direction to reduce the A method of manufacturing a solid electrolytic capacitor, characterized in that the chip component is surface-mountable on the back. In a method for producing a solid electrolytic capacitor in which a solid electrolyte made of a conductive polymer is formed on a foil wound type capacitor element having an anode lead terminal and a cathode lead terminal,
The foil-wound capacitor element is flattened into an oval shape or an elliptical shape to form a flat capacitor element, and after forming a solid electrolyte containing a conductive polymer in the flat capacitor element, the anode lead terminal and the above A resin sheathing body made of a mold resin is directly formed around the flat capacitor element along the flat shape except for the respective tip end sides of the cathode lead terminal, and each tip of the anode lead terminal and the cathode lead terminal is formed. A method of manufacturing a solid electrolytic capacitor, wherein a chip part that can be surface-mounted with a low profile is formed by bending a portion side in a predetermined direction.   The method for producing a solid electrolytic capacitor according to claim 1, wherein the foil wound type capacitor element is a lead in the same direction type.   3. The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein the foil wound type capacitor element is a lead opposite direction type.     The solid electrolytic capacitor manufactured by the manufacturing method of the solid electrolytic capacitor of any one of Claim 1 thru | or 4.

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