JP2007318170A - Manufacture and manufacturing apparatus of solid-state electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a solid-state electrolytic capacitor having little variation of electrical characteristics in a method of manufacturing the same, which is made by immersing conductive polymer as a cathode electrolyte into a capacitor, which is provided with a positive electrode member on which chemical conversion coatings are formed. <P>SOLUTION: According to a method of manufacturing of the present invention, a mixed liquid is obtained in a first process by pouring monomer to be conductive polymer by oxidation polymerization and oxidant into a solution hold concave portion having a capacity corresponding to an outer diameter of each capacitor. In a second process, the capacitor is immersed in the mixed liquid. In a third process, the capacitor is drawn up from the solution hold concave portion. The portion is made to have an almost cylindrical cross section. An opening diameter of the portion is larger than the diameter of the capacitor. A bottom surface diameter of the portion is almost equal to the size of the capacitor and spreads from the bottom surface towards the opening. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for manufacturing a solid electrolytic capacitor.

  Solid electrolytic capacitors in which a capacitor element having a valve action metal member having a chemical conversion film is impregnated with a TCNQ complex salt as an electrolyte are disclosed in JP-B-62-51489, JP-B-62-51491, and JP-B-4-66373. No. 4, US Pat. No. 4,580,855 and the like. Here, TCNQ means 7,7,8,8-tetracyanoquinodimethane.

  As an embodiment of the solid electrolytic capacitor, as shown in FIG. 8, the capacitor element (1) is accommodated in a bottomed cylindrical aluminum case (9), and the case (9) is filled with an epoxy resin (91). A solid electrolytic capacitor in which the opening of the case (9) is sealed is known. As shown in FIG. 9, the capacitor element (1) has an anode foil (11) made of etched aluminum foil on which a chemical conversion film is formed and a counter cathode foil (12), with a separator (13) sandwiched therebetween, This is wound into a roll shape to produce a winding element, and the winding element is impregnated with a solid electrolyte such as a TCNQ complex salt. A pair of lead tab terminals (14) and (14) are drawn from the anode foil (11) and the cathode foil (12), and lead wires (15) and (15) extend from these lead tab terminals.

  In the manufacturing process of the solid electrolytic capacitor, first, an appropriate amount of TCNQ complex salt powder is packed in the case (9), heated to 250 to 350 ° C. to melt the TCNQ complex salt, and the winding element is immersed therein. Then, after impregnating the TCNQ complex salt, the case is quenched to solidify the TCNQ complex salt, and finally, the case (9) is filled with the epoxy resin (91).

  Further, solid electrolytic capacitors using a conductive polymer such as polypyrrole, polythiophene, polyfuran, and polyaniline as an electrolyte have attracted attention as small solid capacitors having a large equivalent capacity and a low equivalent series resistance (ESR). In the solid electrolytic capacitor, similarly to the structure shown in FIG. 9, a winding element was prepared by winding the anode foil (11) formed with a chemical conversion film and the counter cathode foil (12) through a separator (13). Then, a conductive polymer layer is formed in the winding element to constitute the capacitor element (1), and the lead tab terminals (14) and (14) project as shown in FIGS. 6 (a), (b) and (c). After the sealing rubber packing (90) is fitted to the end of the capacitor element (1) to be performed, the capacitor element (1) is accommodated in an aluminum case (9). Then, the rubber packing (90) is clamped from the periphery by drawing the end of the case (9) on the opening side to seal the case (9).

  In the conventional method of manufacturing a solid electrolytic capacitor using a conductive polymer as an electrolyte, a chemical conversion film, a conductive polymer layer, a graphite layer, a silver layer are formed on the surface of an anode sintered body or anode foil made of a valve metal such as aluminum or tantalum. A paint layer is sequentially formed, and a cathode lead wire is connected thereto by a conductive adhesive or the like. In this manufacturing method, an anode foil on which a chemical conversion film is formed and a counter cathode foil are wound through a separator paper, thereby This is considerably more complicated than an ordinary electrolytic capacitor manufacturing method in which an obtained winding element (hereinafter referred to as a capacitor element) is impregnated with an electrolytic solution.

  On the other hand, the conductive polymer layer is formed by an electrolytic polymerization method, a gas phase polymerization method, or the like, but it is easy to form a conductive polymer layer by an electrolytic polymerization method or a gas phase polymerization method in a wound capacitor element. Not. Although a method of forming the chemical conversion film and the conductive polymer layer on the anode foil and then winding it with the counter cathode foil is also conceivable, it is difficult to wind the chemical conversion film and the conductive polymer layer without damaging them.

  The conductive polymer layer can also be formed by a liquid phase chemical polymerization method. In this case as well, conventionally, a monomer that becomes a conductive polymer by oxidative polymerization is diluted with an organic solvent and an oxidizing agent is added. Since the process of immersing and drying the capacitor element in the added chemical polymerization solution was repeated 5 to 10 times, the working efficiency was poor.

Therefore, the applicants made a conductive polymer by oxidation polymerization as a method of producing a solid electrolytic capacitor constituted by impregnating a conductive polymer as a cathode electrolyte into a capacitor element having an anode member formed with a chemical conversion film. The manufacturing method of the solid electrolytic capacitor which has the process of immersing a capacitor | condenser element in this liquid mixture after dissolving an oxidizing agent in a monomer and obtaining a liquid mixture was developed.
JP, 10-50558, A According to this manufacturing method, it is not necessary to repeat the immersion of the capacitor element in the chemical polymerization solution and the subsequent heat treatment many times, and a small, large capacity and low ESR solid electrolytic capacitor is obtained by a simple process. Can be obtained.

  FIG. 7 shows a layout of a manufacturing facility for carrying out the method for manufacturing a solid electrolytic capacitor according to the above-mentioned applicant's proposal.

  In the manufacturing facility, the solution mixing station (5) and the solution impregnation station (6) are connected by a container transport mechanism (4), and an element transport mechanism (3) is provided along the container transport mechanism (4). Has been deployed. The solution mixing station (5) is fed with a container (2) in which a plurality of solution storage recesses (20) are formed, and the conductive polymer and the conductive polymer are put into the solution storage recess (20) of the container (2) by oxidative polymerization. A monomer and an oxidizing agent (dopant) are injected to mix both liquids. This initiates oxidative polymerization of the conductive polymer. Thereafter, the container (2) containing the mixed liquid is transported toward the solution impregnation station (6) by the container transport mechanism (4).

  On the other hand, the element transport mechanism (3) transports a capacitor element group (10) formed by connecting a plurality of capacitor elements to the solution impregnation station (6). Each capacitor element is immersed in the mixed solution injected into each solution containing recess (20).

  As a result, each capacitor element is impregnated with the mixed liquid of the monomer and the oxidizing agent.

  Thereafter, the polymerizing reaction is allowed to proceed for about 30 minutes in air having a temperature of about 30 ° C. to about 50 ° C. and a humidity of 60% or more, and further a drying heat treatment is performed in a furnace at a temperature of about 160 ° C. Thus, a polymer layer is formed on the chemical conversion film of the anode member.

  However, the solid electrolytic capacitor manufactured by the conventional manufacturing method shown in FIG. 7 has a problem that electric characteristics such as ESR vary, and the desired performance cannot be obtained in some cases.

  Therefore, as a result of intensive studies to solve the above problems, the applicants have found that in the conventional production method, the monomer injected into the solution containing recess (20) of the container (2) at the solution impregnation station (6). The mixed state of the mixed solution of oxidant and oxidizer is non-uniform, and this non-uniformity affects the properties of the conductive polymer layer formed on the chemical conversion film of the anode member, so that solid electrolysis as a finished product is achieved. As a result, it was determined that the electrical characteristics of the capacitor were inferior, and the present invention was completed.

  That is, in the method and apparatus for manufacturing a solid electrolytic capacitor according to the present invention, a solution agitation station (7) is provided between the solution mixing station (5) and the solution impregnation station (6), and a monomer and a capacitor element are provided. The mixed state of the mixed solution is made uniform by stirring the mixed solution immediately before the step of impregnating the mixed solution of the oxidizing agent.

  As a result, a conductive polymer layer having good properties is always formed on the chemical conversion film of the anode member in the capacitor element, and the electrical characteristics of the solid electrolytic capacitor as a finished product are stable. Become.

  As a method for stirring the mixed solution, a method in which an air injection nozzle (71) is provided in the solution stirring station (7) and compressed air is sprayed onto the mixed solution can be employed.

  It is also possible to employ a method in which an ultrasonic generator (72) is provided in the solution agitation station (7) and vibration is applied to the mixed solution.

  Furthermore, it is also possible to employ a method in which a stirrer (73) is provided in the solution agitation station (7) and the mixed solution is directly agitated.

  According to the method and apparatus for manufacturing a solid electrolytic capacitor according to the present invention, it is possible to obtain a solid electrolytic capacitor that is small in size and low in capacity and low in ESR and yet has little variation in electrical characteristics.

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

  In the apparatus for producing a solid electrolytic capacitor according to the present invention, as shown in FIG. 1, the solution mixing station (5) and the solution impregnation station (6) are connected by a container transfer mechanism (4). ) Is provided with a solution agitation station (7). An element transport mechanism (3) is arranged along the container transport mechanism (4).

  The solution mixing station (5) is fed with a container (2) in which a plurality of solution storage recesses (20) are formed, and the conductive polymer and the conductive polymer are put into the solution storage recess (20) of the container (2) by oxidative polymerization. The monomer and the oxidizing agent (dopant) are injected to mix both liquids. This initiates oxidative polymerization of the conductive polymer. Thereafter, the container (2) containing the mixed liquid is transported toward the solution stirring station (7) by the container transport mechanism (4).

  In addition, p-toluenesulfonic acid containing 50% of n-butyl alcohol can be used as the oxidizing agent, and 3,4-ethylenedioxythiophene can be used as the monomer.

  As shown in FIG. 2, the solution agitating station (7) is provided with an air injection nozzle (71) for injecting compressed air toward the solution storage recess (20) of the container (2) on the transport table (8). Has been. As a result, compressed air is blown to the mixed liquid of the monomer and the oxidant injected into the solution storage recess (20) of the container (2), and the two liquids are sufficiently stirred to obtain a uniform mixed state.

  Thereafter, the container (2) is transported toward the solution impregnation station (6) by the container transport mechanism (4).

  As shown in FIGS. 3 (a) and 3 (b), the solution agitating station (7) has an ultrasonic generator (72) connected to the transfer table (8), so that the solution storage recess ( It is also possible to employ a method of stirring the mixed solution by applying vibration to the mixed solution in 20).

  Alternatively, as shown in FIG. 4, the solution agitation station (7) is provided with a stirrer (73), and a method of directly agitating the mixed solution in the solution storage recess (20) of the container (2) is adopted. It is also possible.

  Further, in the solid electrolytic capacitor manufacturing apparatus according to the present invention, as shown in FIG. 1, a capacitor element group (10) formed by connecting a plurality of capacitor elements to each other by a device transport mechanism (3) is a solution impregnation station ( In the solution impregnation station (6), each capacitor element is immersed in the mixed solution injected into each solution storage recess (20) of the container (2).

  FIGS. 5A, 5B and 5C show the case in which the capacitor element 1 is immersed in the mixed solution 21 injected into the solution containing recess 20 of the container 2 and then the container 2 In this way, the capacitor element (1) is impregnated with the liquid mixture (21) in the solution containing recess (20).

  Subsequently, the capacitor element (1) is accommodated in a furnace and subjected to heat treatment at a temperature of 200 ° C. or higher. As a result, a conductive polymer layer is formed on the chemical conversion film of the anode member in the capacitor element (1).

  Thereafter, as shown in FIGS. 6A, 6B and 6C, a rubber packing 90 for sealing is fitted into the end of the capacitor element 1 from which the lead tab terminals 14 and 14 protrude. After that, the capacitor element (1) is accommodated in an aluminum case (9). Then, the rubber packing (90) is clamped from the periphery by drawing the end of the case (9) on the opening side to seal the case (9).

  Finally, an aging process is performed. This completes the solid electrolytic capacitor.

  In the method for producing a solid electrolytic capacitor of the present invention, a solution agitation station (7) is provided between the solution mixing station (5) and the solution impregnation station (6), and a monomer and an oxidizing agent are provided in the capacitor element (1). Immediately before the step of impregnating the mixed solution, the mixed solution injected into the container (2) is stirred, so that the mixed state of the mixed solution in the solution impregnation station (6) is made uniform.

  As a result, a conductive polymer layer having good properties is always formed on the chemical conversion film of the anode member constituting the capacitor element (1), and the electrical characteristics of the solid electrolytic capacitor are stable. Become.

  In order to confirm the effect of the present invention, the solid electrolytic capacitor (Examples 1, 2, and 3) prepared by the manufacturing method of the present invention shown in FIG. 1 and the solid electrolytic capacitor prepared by the conventional manufacturing method shown in FIG. The initial electrical characteristics of (conventional example) were compared. The results are shown in Table 1.

  In both the conventional example and the example, the capacitor has a diameter of 6.3 mm, a length of 5.8 mm, an output voltage of 20 V, and a capacitance of 22 μF. In Table 1, Cap. Is an electrostatic capacity of 120 Hz, tan δ is a tangent of a loss angle of 120 Hz, ESR is an equivalent series resistance of 100 kHz, and each shows an average value of n = 30 samples. The standard deviation is shown in parentheses.

    As is apparent from the results in Table 1, the solid electrolytic capacitors (Examples 1 to 3) produced by the production method of the present invention are compared with the solid electrolytic capacitors (conventional example) produced by the conventional production method. Stable electrical characteristics are obtained with little variation.

  In addition, the heat resistance performance of the solid electrolytic capacitors of Examples 1, 2, and 3 and the conventional example was compared by performing a solder heat resistance test. The results are shown in Table 2.

The solder heat resistance test was performed by the VPS method (preheating at 150 ° C. × 120 seconds, followed by heating at 240 ° C. × 50 seconds). In Table 2, ΔC / C indicates the rate of change in capacitance after the test compared to before the test, and LC is the leakage current value after 60 seconds when the rated voltage (20 V) is applied. , The average value of the number of samples n = 30 is shown.

  As is apparent from the results in Table 2, the solid electrolytic capacitors (Examples 1 to 3) produced by the production method of the present invention are compared with the solid electrolytic capacitors (conventional example) produced by the conventional production method. Deterioration of electrical characteristics due to heat is reduced.

  As described above, in the solid electrolytic capacitor manufacturing apparatus according to the present invention, by providing the solution stirring station (7) between the solution mixing station (5) and the solution impregnation station (6), the electrical characteristics are stabilized. A solid electrolytic capacitor can be produced, and a solid electrolytic capacitor with little thermal deterioration can be obtained with respect to heat resistance.

  In addition, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim. For example, in the above embodiment, a solid electrolytic capacitor having a wound capacitor element has been described. However, the present invention can also be implemented in a resin mold type solid electrolytic capacitor using a sintered body such as tantalum. And the same effect can be acquired.

It is a figure which shows the layout of the manufacturing apparatus of the solid electrolytic capacitor which concerns on this invention. It is a side view which shows the air injection nozzle installed in a solution stirring station. It is the top view (a) and side view (b) of the ultrasonic generator installed in a solution stirring station. It is a side view of the stirrer installed in a solution stirring station. It is a figure which shows the process in a solution impregnation station. It is a figure which shows the process of accommodating a capacitor | condenser element in a case and sealing. It is a figure which shows the layout of the conventional manufacturing apparatus. It is a partially broken side view of a solid electrolytic capacitor. It is a partial expansion perspective view of a capacitor element.

Explanation of symbols

(1) Capacitor element
(10) Capacitor element group
(2) Container
(20) Solution storage recess
(3) Element transport mechanism
(4) Container transport mechanism
(5) Solution mixing station
(6) Solution impregnation station
(7) Solution stirring station
(71) Air injection nozzle
(72) Ultrasonic generator
(73) Stirrer
(8) Transfer table
(9) Case

Claims (6)

In a method for producing a solid electrolytic capacitor constituted by impregnating a conductive polymer as a cathode electrolyte into a capacitor element having an anode member formed with a chemical conversion film,
A first step of injecting a monomer that becomes a conductive polymer by oxidative polymerization and an oxidant into each of the plurality of solution containing recesses formed in the container to obtain a mixed solution;
A second step of immersing the plurality of capacitor elements simultaneously in the mixed solution in each of the solution containing recesses, and
And a third step of simultaneously pulling up the plurality of capacitor elements from the respective solution containing recesses,
Each of the solution storage recesses has a size capable of storing each of the capacitor elements one by one. The capacitor element has a configuration in which the anode foil on which the chemical conversion film is formed and the counter cathode foil are wound in a roll shape via a separator,
Each of the solution storage recesses has a substantially circular cross section perpendicular to the depth direction of the recess, the diameter of the cross section gradually decreases from the opening toward the bottom, and the diameter of the bottom is The method for producing a solid electrolytic capacitor according to claim 1, comprising an inner wall surface having a shape substantially equal to the outer diameter of the capacitor element. Between the first step and the second step, the step of stirring the mixed solution in each of the solution storage recesses by blowing compressed air on the mixed solution,
The method of manufacturing a solid electrolytic capacitor according to claim 2, wherein the compressed air is sprayed toward an inner wall surface of each solution housing recess. In a solid electrolytic capacitor manufacturing apparatus configured by impregnating a conductive polymer as a cathode electrolyte into a capacitor element having an anode member formed with a chemical conversion film,
A solution mixing station for injecting a monomer that becomes a conductive polymer by oxidative polymerization and an oxidant into each of the plurality of solution containing recesses formed in the container to prepare a mixed solution;
An impregnation station for simultaneously immersing a plurality of the capacitor elements in the mixed liquid in each of the solution containing recesses,
Each of the solution storage recesses has a size capable of storing each of the capacitor elements one by one. The capacitor element has a configuration in which the anode foil on which the chemical conversion film is formed and the counter cathode foil are wound in a roll shape via a separator,
Each of the solution storage recesses has a substantially circular cross section perpendicular to the depth direction of the recess, the diameter of the cross section gradually decreases from the opening toward the bottom, and the diameter of the bottom is 5. The apparatus for manufacturing a solid electrolytic capacitor according to claim 4, further comprising an inner wall surface having a shape substantially equal to the outer diameter of the capacitor element. A stirring station is provided between the solution mixing station and the impregnation station to stir the mixed solution in each of the solution storage recesses by blowing compressed air on the mixed solution,
6. The apparatus for producing a solid electrolytic capacitor according to claim 5, wherein the agitation station is provided with a compressed air injection nozzle that blows the compressed air toward an inner wall surface of each of the solution storage recesses.

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