JP2010182745A - Method of manufacturing solid electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a small-sized and highly reliable solid electrolytic capacitor by stacking a plurality of solid electrolytic capacitor elements in a thickness direction to reduce the volume of a positive electrode. <P>SOLUTION: A capacitor element assembly 13 has the positive electrode formed on an end of a metal base material 10 and a porous layer 12 formed in a central part of the base as a negative electrode. The assemblies are stacked such that the positive electrodes thereof and the negative electrodes thereof are opposed to one another and the negative electrodes of the element assemblies 13 are joined with one another with a conductive adhesive 14. A resultant stack is molded with a resin 16. A resultant molded body is cut in a direction in which the element assemblies are stacked at the position of the positive electrode of each element assembly 13. The positive electrode of each element assembly is exposed from a cutting plane of the molded body and a positive-electrode-side external connection terminal 17 is connected to an exposed part. A negative-electrode-side external connection terminal 15 communicating with the outside of the molded body is connected to the negative electrode of the capacitor element assembly in the molded body. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a solid electrolytic capacitor that can be used in various fields such as a noise filter and a smoothing element, and is formed by stacking and integrating one or more solid electrolytic capacitor elements having a substantially flat plate shape.

  As a solid electrolytic capacitor element having a substantially flat plate shape, a solid electrolytic capacitor element as shown in FIG. 9A is known. This solid electrolytic capacitor element is composed of an anode portion 1, a cathode portion 2, and an insulating resin 3.

  The anode part 1 is a metal plate having a valve action such as aluminum, tantalum, niobium, titanium or the like, or a metal plate made of a metal plate made of an alloy thereof or an alloy thereof, or a metal plate having a valve action. A metal powder having a valve action is integrated by sintering. An oxide film is formed on the entire surface of the anode portion 1, and an insulating resin 3 is formed on one end thereof.

  The surface of the anode portion 1 on which this oxide film is formed is divided into two regions, a left region and a right region in the figure, with the insulating resin 3 as a boundary. Solid electrode layer, graphite layer, and silver paste layer, or solid electrolyte layer, graphite layer, and metal plating layer, or solid electrolyte layer and metal plating layer are sequentially formed in the right region to form cathode portion 2 To do. In the left region, the oxide film is removed to form the external terminal portion of the anode portion 1. The oxide film in the right region functions as a dielectric layer of the solid electrolytic capacitor element.

  Further, as shown in FIG. 9B, a capacitor 10 is also known in which an insulating resin 3 is provided at both ends and the anode portion 1 is exposed.

  In order to reduce the size, increase the capacity, and reduce the impedance of such a solid electrolytic capacitor element, it is effective to stack a plurality of solid electrolytic capacitor elements in the thickness direction and electrically connect them to form a stack. It is.

  As a lamination method, there is a method in which the cathode portions of the solid electrolytic capacitor elements are connected with a conductive adhesive, and one end portion of each anode portion is bent and joined to the lead frame by welding (for example, a patent) Reference 1). In addition, a conductive member is attached to the end of the capacitor element to make electrical connection between the anode parts (see, for example, Patent Document 2), or a conductive member is interposed between the end parts of the capacitor element, A method of connecting each other is also known (for example, see Patent Document 3).

JP-A-11-135367 JP 2005-79463 A JP 2006-128247 A

  However, in the invention of Patent Document 1, since the end portion of the anode portion is bent and joined to the lead frame by welding, the bent portion becomes more complex as the number of layers increases. Therefore, it is difficult to stack five or more solid electrolytic capacitor elements.

  On the other hand, in the inventions of Patent Documents 2 and 3, it is not necessary to bend the end portion of the anode portion, but the end portion of the anode portion of the capacitor element to be laminated is parallel, and an insulating spacer or conductive member is provided between the anode end portions. Intervene. Therefore, it is necessary to adjust the interval between the anode end portions, and it is necessary to increase the volume of the anode portion. However, since the anode part does not contribute to the capacitance of the solid electrolytic capacitor, securing the volume of the anode part due to the shape of the solid electrolytic capacitor is an obstacle to further downsizing the solid electrolytic capacitor. It was.

  Furthermore, when simply laminating capacitor elements, a positional shift occurs when laminating due to variations in the size of the capacitor elements themselves, making it difficult to align the ends of the capacitor elements. Further, if there is a deviation in the end of the capacitor element, there is also a problem that when the external terminal is connected to the end of the laminated capacitor element, the connection between the terminal and the anode body becomes insufficient.

  Further, in the electrolytic capacitors described in Patent Documents 1 to 3, the ratio of the anode portion to the entire volume of the solid electrolytic capacitor is high. As a result, the anode portion and the external terminal of the anode, the connected substrate, and the current path to the device Will become longer. For this reason, in an electrolytic capacitor that requires transient response characteristics, current supply has been delayed.

  The present invention has been made in order to solve the above-described problems, and its purpose is to reduce the volume of the anode part by stacking a plurality of solid electrolytic capacitor elements in the thickness direction, and particularly to reduce the size and reliability. An object of the present invention is to provide an excellent method for producing a solid electrolytic capacitor.

  In order to achieve the above object, the method for producing a solid electrolytic capacitor of the present invention includes a capacitor body in which an anode portion is formed at an end portion of a metal substrate and a cathode portion is formed at a central portion, and anode portions of the respective body bodies, The cathode parts are opposed to each other, and the cathode parts of each element body are laminated in a state of being electrically connected to each other, and this laminate is molded with a resin. The anode part of each element body is exposed on the cut surface, and an external connection terminal on the anode side is connected to the exposed part, and the cathode part of the capacitor element body in the mold body is cut. Is characterized in that an external connection terminal on the cathode side communicating with the outside of the mold body is connected.

  In addition, after applying a resist to a plate-like metal substrate in a lattice shape and forming a porous layer by etching, the plate-like metal substrate is cut vertically and horizontally to form individual capacitor bodies, It is also an embodiment of the present invention to mold the external connection terminal for the cathode after laminating the lowermost or uppermost element body of the capacitor body.

  According to the present invention having the above-described configuration, since it is not necessary to increase the volume of the anode part in order to attach the conductive member to the anode part, the production of the solid electrolytic capacitor that suppresses the volume of the anode part that does not contribute to the capacity A method can be provided. Further, since the exposed anode terminal portion has a large area, the connection strength with the external terminal to be connected can be strengthened, so that the reliability can be increased.

It is a top view which shows the 1st process and 2nd process in Example 1 of this invention. It is a figure which shows the 3rd process in Example 1 of this invention, (A) is a top view, (B) is a perspective view. It is sectional drawing which shows the 6th process in Example 1 of this invention. It is sectional drawing which shows the 7th process in Example 1 of this invention. It is sectional drawing which shows the 8th process in Example 1 of this invention. It is sectional drawing which shows the 9th process in Example 1 of this invention. It is a perspective view at the time of making the metal base | substrate 10 in Example 2 of this invention into this H shape. It is a perspective view at the time of setting it as the shape which provided the recessed part in the surface part, bottom face part, and right and left side surface of the metal base | substrate 10 in Example 2 of this invention. It is sectional drawing which shows the structure of the conventional solid electrolytic capacitor element.

  Embodiments of a method for producing a solid electrolytic capacitor element according to the present invention will be described below with reference to the drawings. It should be noted that assumptions common to those already described in the background art and problems are omitted as appropriate.

[Configuration of Example 1]
The present embodiment relates to a method of manufacturing a solid electrolytic capacitor according to the following first to ninth steps, and a solid electrolytic capacitor manufactured as described above. Here, each process step is shown in FIGS. 1 to 6, and part of the process is shown in a perspective view of FIG.

First step: Preparation of metal substrate ... FIG. 1 (A)
First, a plate-shaped metal base 10 made of a valve metal, that is, a valve action metal is prepared, and masking is performed by printing a resist resin 11 in a lattice pattern on both sides. Here, the type of the metal substrate 10 is desirably aluminum, and the thickness is generally considered to be about 300 to 800 μm. However, the type and thickness of the metal can be appropriately changed. For example, valve action metals such as tantalum, niobium, and titanium can be used in addition to aluminum.

Second step: Formation of porous body layer by etching treatment ... FIG. 1 (B)
Subsequently, an etching process is performed on the masked metal substrate 10. The depth of the etching process is about 100 μm from the surface on both the front and bottom sides of the metal substrate 10. By this etching process, the porous layer 12 is formed in the part where the metal substrate 10 is etched. Here, as the means for the etching treatment, known means such as alternating current or direct current etching can be used.

Third step: Cutting into individual pieces ... FIG.
Thereafter, the metal substrate 10 that has been subjected to the etching process is cut into individual capacitor bodies 13. The parts to be cut are the AA ′ part where the resist resin remains at both ends and the BB ′ part including the etched part, and the metal substrate 10 is cut together with the resist resin 11 as shown in FIG. The individual capacitor element bodies 13 cut in this way are thicker at both ends by the resist resin 11. In addition, the central portion subjected to the etching process is a porous body as shown in FIG.

Fourth Step: Formation of Dielectric Oxide Film and Solid Electrolyte Layer The porous body layer 12 of the capacitor body 13 cut into pieces is anodized. As a result, a dielectric oxide film is formed on the porous body layer 12. Further, a solid electrolyte layer is formed on the dielectric oxide film. Here, a conductive polymer is suitable as the solid electrolyte layer, and such a conductive polymer layer is formed by a known technique such as chemical polymerization or electrolytic polymerization based on thiophene, pyrrole, or the like. be able to.

  In this case, since the metal aluminum which is the metal substrate 10 that is not etched (the porous layer 12 is not formed) is exposed on the cut surface, the dielectric oxide film and the solid electrolyte are exposed in that portion. There is no need to form a layer. In that case, these treatments can be performed after applying a resist to a portion where the formation of the dielectric oxide film and the solid electrolyte layer is unnecessary.

Fifth Step: Formation of Cathode Terminal Portion A cathode terminal portion composed of a graphite (Gr) layer and a silver paste layer is formed on the solid electrolyte layer formed as described above. The means for forming the graphite (Gr) layer and the silver paste layer may be the same as a known technique in a solid electrolytic capacitor.

Sixth step: stacking of capacitor bodies and electrical connection between cathodes ... FIG.
The cathode parts of the capacitor body 13 on which the cathode terminal part is formed are joined together with the conductive adhesive 14. At this time, the conductive adhesive 14 is also applied onto the solid electrolyte layer on the side surface of the element body, and the cathodes are electrically connected. Further, a metal plate piece to be the cathode external terminal 15 is attached to the lowermost surface of the laminate by the conductive adhesive 14.

  The cathode external terminal 15 may be a metal plate piece such as copper, but may be iron plated with copper. In any case, when aluminum is used as the material of the metal substrate 10, it is difficult to solder the aluminum. Therefore, the cathode external terminal 15 is preferably fixed by the conductive adhesive 14.

7th step: Resin mold of laminated body ... FIG.
The entire laminated body of the capacitor body 13 thus formed is molded using a mold resin 16 such as an epoxy resin. The mold resin 16 may enter the gap between the anode portions of the element body.

  In this resin molding, at least the connection surface of the cathode external terminal 15 attached to the lower surface of the capacitor element is not covered. For example, the laminated body of the base body 13 is mounted on a separately prepared film, and the mold resin 16 is filled thereon, so that the mold resin 16 is formed on the exposed surface of the cathode external terminal 15 connected to the lower surface of the laminated body. Does not enter, and the exposed surface is not covered with the mold resin 16. Further, after molding the whole, it is possible to remove the mold resin 16 and expose the cathode external terminal 15.

Eighth step: Cutting the mold body ... FIG.
After the entire laminated body of the capacitor body 13 is resin-molded, it is cut at a position including a part of the anode portion of each capacitor body 13 to expose the metal substrate 10 that is the anode portion from the cut surface. After molding in this way, the anode part is exposed to one plane by cutting at the anode part of the element body 13.

Ninth step: Connection of external terminals ... FIG.
A metal plate piece to be the external connection terminal 17 of the anode part is attached to the exposed metal base 10 by welding such as ultrasonic welding or laser welding. At the time of this welding, it is preferable that the external connection terminal 17 is attached so that a metal plate piece is processed into an L shape in advance and arranged along the side surface and the bottom surface.

[Effects of Example 1]
In the present embodiment having the above-described steps, the capacitor element 13 is laminated and then molded, so that an insulating spacer or a conductive member is interposed between the anode end portions. There is no need to fix. That is, since it is not necessary to increase the volume of the anode part in order to attach the conductive member to the anode part, an increase in the volume of the anode part that does not contribute to the capacity can be suppressed.

  Moreover, after adhering the cathode parts with the conductive adhesive 14 and molding the entire capacitor element, the mold body is cut so as to include both ends of the metal base 10 to expose the metal base 10, so that it is exposed. The anode section has a flat cross section. For this reason, it is not necessary to align the end portions of the anode portion. Further, since the molded body is cut again so as to include both end portions of the metal substrate 10 after molding, the anode portion can be made to have a minimum size.

  Furthermore, after molding the entire capacitor element, the mold body was cut so as to include both end portions of the metal substrate 10, so that the area of the anode portion is widely exposed. Therefore, the area of the connection portion between the external connection terminal 17 and each capacitor element body 13 can be increased. For this reason, it becomes possible to strengthen the connection strength with the external connection terminal 17 to be connected. In addition, since it is exposed in a wide area of the end face of the capacitor element, it is easy to weld an external terminal to this portion. The metal plate piece to be the external connection terminal can be arranged along the side surface and the bottom surface by processing it in an L shape in advance, and the welding area can be further expanded.

[Other embodiments]
In addition, this invention is not limited to the said embodiment, The thing illustrated next and other embodiment other than that are included.

(a) When the capacitor body 13 shown in FIG. 2A is formed, instead of etching the plate-like metal base 10 and cutting it into a lattice shape as in the first embodiment, FIG. A) A metal substrate 10 having an H-shaped cross section such as aluminum or copper as shown in (B) can be used. That is, a valve action metal such as aluminum is vapor-deposited in the concave portion of the metal substrate 10, and this vapor deposition layer is used as the porous body layer 12. By using the metal substrate 10 having an H-shaped cross section, a solid electrolytic capacitor element having a wider porous body portion can be obtained as compared with the case where the porous body layer 12 is formed by etching. Thereby, since the volume of the cathode portion is increased, the capacitance can be increased.

(b) The shape of the metal substrate 10 may be a shape in which concave portions are provided on the surface portion, the bottom surface portion, and the left and right side surfaces of the metal base as shown in FIGS. By providing the recesses on all sides, it is possible to further increase the volume of the porous layer to be deposited.

(c) Instead of using an H-shaped metal substrate having the same shape as that of the capacitor body 13 as shown in FIG. 2A, as shown in FIGS. It is also possible to form a cathode portion having a porous layer by etching or a porous layer by vapor deposition, and then cut each individual capacitor element body 13.

(d) In FIG. 7, aluminum or copper can be used as the material of the metal substrate having an H-shaped cross section. In this case, in order to prevent the anode portion from being short-circuited when the capacitor body 13 is separated into individual pieces, the position of the conductive adhesive 14 inserted between the laminated bodies is considered, or the individual piece state In the capacitor element body 13, it is necessary to consider such as forming an insulating film on the surface of the anode part.

(e) In the first embodiment, the cathode external terminals 15 and the external connection terminals 17 are formed of metal plate pieces. However, the shapes of the terminals 15 and 17 are not limited to those illustrated. It is also possible to expose only a part of the terminals from the resin mold part or to draw out multiple terminals. Also, the drawing position and shape can be appropriately changed according to the use of the capacitor.

(f) In the embodiment of FIG. 7, the cathode portion was formed later on the metal substrate 10 forming the individual capacitor elements 13 or the metal substrate 10 forming the capacitor elements 13 continuous in a rod shape. Also for the plate-like metal substrate as in Example 1, the cathode part can be formed after cutting into individual capacitor bodies.

(g) In Example 1, in the “sixth step: lamination of capacitor body and electrical connection between cathodes”, the cathode lower terminal 15 is connected to the lowermost surface of the laminate by the conductive adhesive 14. After attaching the metal plate piece, the “seventh step: resin molding of the laminated body” is performed. After the resin molding of the laminated body is performed, the metal plate piece to be the cathode external terminal 15 of the molded laminated body The cathode external terminal 15 may be connected by exposing the portion to be attached. In this case, it is not necessary to use the film exemplified in the seventh step of Example 1, and according to a method such as polishing, the flatness for connecting the cathode external terminal 15 can be further increased. become able to.

DESCRIPTION OF SYMBOLS 1 ... Anode part 2 ... Cathode part 3 ... Insulating resin 10 ... Metal substrate 11 ... Resist resin 12 ... Porous body layer 13 ... Capacitor body 14 ... Conductive adhesive 15 ... Cathode external terminal 16 ... Mold resin 17 ... External connection Terminal

Claims (7)

  Capacitor bodies in which the anode part is formed at the end of the metal substrate and the cathode part is formed at the center part, the anode parts of each element body are opposed to each other, and the cathode parts of each element body are electrically connected to each other. The laminated body is molded with resin, the mold body is cut along the stacking direction of each element body at the position of the anode part of each element body, and the anode part of each element body is formed on the cut surface. And connecting the anode side external connection terminal to the exposed portion, and connecting the cathode side external connection terminal communicating with the outside of the mold body to the cathode part of the capacitor body in the mold body. A method for producing a solid electrolytic capacitor.   The capacitor body is formed by applying a resist in a lattice shape to a plate-like metal substrate, forming a porous layer by etching, and then cutting the plate-like metal substrate vertically and horizontally. Item 2. A method for producing a solid electrolytic capacitor according to Item 1.   The laminated body is molded such that the external connection terminals for the cathode are laminated on the lowermost layer of the laminated capacitor body or the surface of the uppermost body, and the external connection terminals are exposed. The manufacturing method of the solid electrolytic capacitor of Claim 1 or Claim 2.   2. The cathode capacitor external connection terminal is connected to the exposed portion after the laminated capacitor body is molded, the portion to which the cathode external connection terminal is connected is exposed, and the exposed portion is connected. 2. A method for producing a solid electrolytic capacitor as described in 2.   After the individual capacitor element is formed on the cathode part of the capacitor element body, a porous layer or a vapor deposition layer is formed in the central part thereof, and a dielectric oxide film and a solid electrolyte layer are formed in the porous layer or vapor deposition layer part. 5. The method of manufacturing a solid electrolytic capacitor according to claim 1, wherein the manufacturing method is performed by forming the capacitor.   A porous layer or a vapor deposition layer is formed on the cathode portion of the capacitor element body in the state of a plate-like metal substrate or a rod-shaped metal substrate that is a material of a plurality of capacitor element bodies, and the porous layer or vapor deposition layer portion Furthermore, it manufactures by forming a dielectric oxide film and a solid electrolyte layer in any state before and after the cutting process of the individual capacitor elements. The manufacturing method of the solid electrolytic capacitor as described in a term. 6. The metal base portion exposed to the anode portion is covered with a resist when the dielectric oxide film and the solid electrolyte layer are formed on the individual capacitor element body. 6. A method for producing a solid electrolytic capacitor according to 6.

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