JPH0821517B2 - Method for manufacturing solid electrolytic capacitor - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a method for manufacturing a solid electrolytic capacitor,
More specifically, the present invention relates to a product configured to increase production efficiency and reduce variations in product quality.

[Prior art]

There are various types of capacitors, and among them, there is a solid electrolytic capacitor that enables a large capacity while achieving a reduction in size. This solid electrolytic capacitor is a polar capacitor in which an oxide film formed on the surface of an electrode metal serves as a dielectric between electrode plates, and the electrode metal is used as an anode, and an electrolyte provided so as to enclose the electrode metal is used as a cathode. It Also. Tantalum, aluminum, etc. are used for the electrode metal, and, for example, in the case of a tantalum electrolytic capacitor, its manufacture is
In general, the procedure is as follows. As shown in FIG. 5, the tantalum powder b is packed in the mold a, the lead wire c is inserted into the mold a, and then the tantalum powder b in the mold a is pressure-molded by the pressing mold d. After manufacturing the capacitor element molded bodies b one by one in this way, as shown in FIG. 6, a large number of capacitor elements are collectively set in the vacuum sintering furnace e, and the capacitor element molded body b'is formed. ′ Is sintered. Further, after this sintering treatment, a large number of capacitor elements connected to the electrode bar f by welding are dipped in the chemical conversion liquid g and subjected to chemical conversion treatment to form an oxide film (5 Tantalum oxide) is formed. Then, after that, the capacitor element is impregnated with an electrolytic solution such as manganese nitrate, and the manganese nitrate is thermally decomposed to generate solid manganese dioxide serving as the first cathode material between the tantalum powders. In addition, a graphite treatment and silver coating are applied to build up the graphite and silver of the second and third cathode materials on the outside of the manganese dioxide, thereby forming a capacitor element. After such a capacitor element forming step, a capacitor is finally completed through a solder coating on the capacitor element, a case assembling step, a marking step, and the like.

[Problems to be Solved by the Invention]

However, the above conventional manufacturing method has the following problems. That is, in the pressure molding process, the sintering process, and the chemical conversion treatment process, each process is intermittently performed one by one or every many, so that there is a problem that the production efficiency is not so good. . Such a problem is that a lead wire is continuously supplied in a continuous manner, and the molded body can be continuously formed on the lead wire at predetermined intervals, and the capacitor element thus formed is molded. The problem can be solved if the body is connected to the lead in a post process so that each process can be continuously performed. However, in the conventional pressure-molding process, the lead wire is inserted into the electrode material in the mold for processing, and the lead wire must be used separately. It is not possible to perform continuous processing such as. In addition, in order to improve the production efficiency as much as possible, the capacitor element is not used in the sintering process or chemical conversion process.
Batch processing is performed by setting each lot in a sintering furnace or a chemical conversion tank. However, in the case of batch processing, since it is difficult to uniformly perform processing on each work, variations in product quality of capacitors are likely to occur. The present invention has been conceived under the circumstances as described above, and provides a method for manufacturing a solid electrolytic capacitor configured to increase production efficiency and reduce variations in product quality. The purpose is to do.

[Means for Solving the Problems]

In order to solve the above problems, the present invention takes the following technical means. That is, in the method for manufacturing a solid electrolytic capacitor of the present invention, a plurality of electrode material-filled recesses lined up at predetermined intervals on the upper surface of a lead wire continuously supplied in series and these electrode material-filled recesses are longitudinally cut. The operation of setting in the wire receiving groove of the mold having the wire receiving groove formed as described above and press-molding the powdery electrode material filled in the respective electrode material filling recesses by the pressing body is repeated. By this, with respect to the lead wire, a step of integrally forming a molded body of the capacitor element at predetermined intervals, and a molded body of the capacitor element sent in a state of being connected to the lead wire,
Basically, the method further includes the step of setting the lead wire at predetermined intervals in a vacuum sintering furnace and sintering. In addition, in a preferred embodiment, in addition to the above steps, a step of performing a chemical conversion treatment by continuously passing a capacitor element, which is sent in a state of being connected to a lead wire after the sintering, through a chemical conversion solution. Is added.

[Operation and effect of the invention]

In the step of forming a molded body of a capacitor element, a wire of a mold having a plurality of electrode material-filled recesses arranged on the upper surface at predetermined intervals and a wire-accommodating groove formed so as to cross the electrode material-filled recesses vertically. The lead wire is set in the accommodating groove, and the plurality of electrode material filling recesses are filled with the powdery electrode material. Since the wire accommodating groove is formed so as to be vertically cut into the plurality of electrode material filling concave portions, the electrode material filled in the respective filling concave portions is pressure-molded by, for example, an integral pressure body to obtain a constant length. A plurality of capacitor element forming bodies can be integrally formed on the lead wire in a certain range at the same time. By the way, as described above, the wire accommodating groove is formed on the upper surface of the mold so as to vertically cut the electrode material filling concave portion. It may be set in the wire accommodating groove so as to be positioned in the electrode material filling concave portion. Therefore, it is not necessary to set separate lead wire wires one by one as in the conventional case, and the molded capacitor element bodies are separated by a predetermined distance from the lead wire wires sent in series. It can be continuously formed. Further, in a preferred embodiment, the molded body of the capacitor element thus formed is sent to the next sintering step while being still connected to the wire for lead wire, and thereafter, for the lead wire. Since it is sent to the chemical conversion treatment step while being connected to the wire, each of these step treatments can be performed continuously. As described above, in the case of the present invention, the molded body of the capacitor element can be continuously formed on the lead wire to be continuously fed, and the pressure molding step, the subsequent sintering step and the chemical conversion treatment step are performed. Since each of the above process steps can be continuously performed in series, the production efficiency is improved. Further, since batch processing is not performed as in the conventional case, variations in product quality are reduced.

[Explanation of the embodiment]

The present invention relates to a method for manufacturing a solid electrolytic capacitor. As described above, the solid electrolytic capacitor is formed by pressing a powdery electrode material into a predetermined shape to form a capacitor element molded body, sintering the molded body, and then subjecting it to chemical conversion treatment. A capacitor element is formed by forming an oxide film as a dielectric on the surface of the electrode metal and impregnating the capacitor element with an electrolyte serving as a cathode.After that, the solder coat and case assembly steps are performed. It is produced through. The present invention particularly relates to a pressure molding step of forming the molded body, a sintering step of sintering the molded body, and a manufacturing method in a chemical conversion treatment step, which will be described below with reference to FIGS. 1 to 4. Description will be made with reference to the drawings. 1 and 4 show the mold 1 and the pressurizing body 2 used in the pressure forming process according to the present embodiment, FIG. 2 shows the vacuum sintering furnace 3 and FIG. Shows the chemical conversion tanks 4, respectively. The mold 1 has a plurality of electrode material-filled recesses 5 arranged in a straight line on the upper surface of the mold 1, and a wire accommodating wire extending linearly so as to vertically cut through the plurality of electrode material-filled recesses 5. The groove 6 is formed. A powdery electrode material A is packed in the electrode material filling recess 5, and a wire W for a lead wire is set in the wire housing groove 6. Also. The lead wire accommodating groove 6 is provided over the entire length in the longitudinal direction of the mold 1, and is formed shallower than the electrode material filling concave portion 5. Therefore, the wire W for the lead wire is placed in the wire receiving groove 6 in the electrode material A.
However, in the state where they are set in the electrode material filling concave portions 5, the lead wire W has the electrode material filling concave portions 5
The electrode material A in the inside can be penetrated. In addition,
In this example, a plurality of the electrode material filling concave portions 5 are provided in order to improve the production efficiency, but the number may be only one. Further, the pressurizing body 2 is arranged above the mold 1.
On the lower surface thereof, the same number of pressing portions 7 as the electrode material filling concave portions 3 are arranged in a straight line at the same pitch as the electrode material filling concave portions 5 and in a shape corresponding to the electrode material filling concave portions 5. The mold 1 and the pressurizing body 2 are attached to, for example, a pressing device (not shown) so that the pressurizing body can be moved up and down. A quartz tube or the like is used for the vacuum sintering furnace 3, and
Heating at the time of sintering is performed by dielectric heating or heating of a lamp. In the case of the illustrated example, the vacuum sintering furnace 3 is formed in a substantially cylindrical shape, and seal portions 8 are provided at both ends thereof. The seal portion 8 is formed with a wire introducing port (not shown) for introducing the lead wire W into the furnace, and is configured so that the diameter of the wire introducing port can be increased or decreased. . When the lead wire W is introduced into the furnace or is sent out from the furnace, the wire introduction port has a molded body A'of a capacitor element described later.
However, when operating the device, the diameter of the wire introduction port is set to the wire W for the lead wire.
The diameter is reduced to a size corresponding to the diameter, and the gap with the lead wire W is closed to seal the furnace. In this case, it is easy to tighten the thin wire having a uniform cross-sectional shape to close the gap between the wires, so that the furnace can be reliably sealed. Further, the vacuum sintering furnace 3 is connected to a vacuum pump (not shown), and the inside of the furnace is evacuated by drawing air in the furnace by this pump. Further, as shown in FIG. 2, a plurality of pairs of induction coils 9a, 9b are arranged around the vacuum sintering furnace 3 so as to sandwich the vacuum sintering furnace 3 from both sides. Above induction coil 9
The a and 9b are connected to a high frequency power supply device (not shown).
When a current is applied to the induction coils 9a, 9b, the induction coils 9a, 9b
A magnetic field that changes with time according to the change in the high-frequency current is formed between 9b. Since the molded body A'of the capacitor element set in the furnace is obtained by solidifying the powder of the electrode material which is a conductor, the electrode material forming the molded body A'is formed by the electromagnetic induction effect by the change of the magnetic field. An eddy current is induced inside, and the resistance heating effect heats and sinters the molded body A '. Further, the chemical conversion liquid L is stored in the chemical conversion liquid tank 4, and a guide roller 10 and a guide rail (not shown) for guiding the lead wire W or the capacitor element are additionally provided. Next, a flow of a series of process treatments in the pressure molding process, the sintering process, and the chemical conversion treatment process will be described. As shown in FIG. 1 (a), the wire receiving groove 6 of the mold 1
In addition, the lead wire W is provided with the electrode material filling concave portions 5 ...
Then, the powdery electrode material A is set. The wire W for a lead wire is unwound from a wire reel (not shown) around which the wire W is wound and continuously supplied, and the wire W is held in the unwound state in the wire accommodating groove 6
Set in. Further, as the electrode material A, tantalum powder, aluminum powder, or the like is used. When the lead wire W and the electrode material A have been set in this manner, as shown in FIG.
Are moved downward, and the electrode material A in each electrode material filling concave portion 5 is pressed by the plurality of pressing portions 7. As a result, the molded body A'of the capacitor element is integrally formed on the lead wire W. Further, since a plurality of electrode material filling concave portions 5 are provided, a plurality of molded bodies A ′ can be formed at one time by one molding. After the pressure molding, as shown in FIG. 1 (c), the pressure body 2 is moved upward and the mold is opened. Further, the lead wire W is lifted by a lead wire feeding mechanism (not shown) having a lift-up mechanism, and the lead wire W and the molded body A ′ are removed from the mold 1. In addition, it is sent forward a predetermined distance. At this time, the plurality of molded bodies A ′ ... Are sent in a state of being connected to the lead wire W in series. In order to more smoothly remove the molded body A'from the mold 1, the mold 1
A lift pin 11 for pushing up the molded body A ′ as shown in FIG. 4 may be provided therein. Further, as shown in FIG. 1 (d), the part of the lead wire W newly positioned on the mold 1 is set in the wire accommodating groove 6 and the same procedure as above is performed. , A plurality of molded bodies A '... Lead wire W
Newly formed on top. In this case, the lead wire W
Since it suffices to set the intermediate portion in the mold 1 and it is not necessary to cut the lead wire W one by one, the molded body A ′ is continuously connected to the lead wire W sent in series. Can be formed in a desired manner. After that, the series of operations described above is repeated to continuously form a plurality of molded bodies A ′. In this way, the molded body A ′ of the capacitor element continuously formed on the lead wire W is sent to the next sintering step while being kept connected to the lead wire W. As shown in FIG. 2, the lead wire W and the molded bodies A ′ ... Formed on the wire at predetermined intervals are
While being introduced into the furnace from the wire introduction port at one end of the vacuum sintering furnace 3, the lead wire W is held in a cantilevered manner at the seal portions 8 at both ends of the vacuum sintering furnace 3. , Set in the furnace. Further, the processed capacitor element is discharged from the furnace, and the lead wire W and the molded body A ′ ... which are sent in series are newly set in the furnace. After that, the same operation is repeated,
The process treatment is continuously performed. Further, after this sintering step, the capacitor element is sent to the chemical conversion treatment step while being connected to the lead wire W. As shown in FIG. 3, the lead wire W and the sintered body B of the capacitor element are introduced into the chemical conversion bath 4 while being fed by the feed mechanism and being guided by the guide roller 10 and the like. It is passed through the chemical conversion liquid L. As a result, the chemical conversion treatment for forming an oxide film serving as a dielectric is continuously performed on the sintered body B of the capacitor element that is sent in series. Further, the capacitor element which has been subjected to the chemical conversion treatment in this way is sent to a post-process and subjected to various predetermined treatments to finally complete the capacitor. In this case, similarly to the above, the capacitor element may be fed in a state of being connected to the lead wire, or the lead wire W may be cut into a predetermined length and one capacitor element at a time. You can also send it. By the way, in the case of the present invention, as described above, in the production of the solid electrolytic capacitor, the series of process steps of the pressure forming step, the sintering step and the chemical conversion treatment step can be continuously performed. Therefore, the production efficiency is much better than the conventional one. Moreover, in the case of this example, a plurality of molded bodies can be formed by one molding in the pressure molding step.
It greatly contributes to the improvement of production efficiency.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a mold and a pressurizing body according to an embodiment of the present invention, a diagram showing a series of operations in a pressure molding step, and FIG. 2 is a vacuum baking according to the embodiment. Fig. 3 is a diagram schematically showing a furnace, Fig. 3 is a diagram schematically showing a chemical conversion solution tank according to the example, and Fig. 4 is a schematic external view of a mold according to the example.
5 to 7 are views showing a conventional example. 1 ... Mold, 3 ... Electrode material filling recess, 4 ... Wire receiving groove, A ... Electrode material, A '... Molded body, W ... Lead wire.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01G 13/00 371 E 7924-5E

Claims (2)

[Claims] 1. A plurality of electrode material-filled recesses lined up at predetermined intervals on a top surface of a wire for a lead wire which is continuously supplied in series, and a wire housing formed so as to vertically cut through these electrode material-filled recesses. The wire for the lead wire is set by repeating the operation of setting the powdery electrode material filled in each of the electrode material filling concave portions with a pressing body while setting it in the wire accommodating groove of the die having the groove. On the other hand, the step of integrally forming the molded body of the capacitor element at predetermined intervals, and the molded body of the capacitor element sent in a state of being connected to the lead wire are carried out at the predetermined length of the lead wire. The method for producing a solid electrolytic capacitor, comprising the steps of: setting in a vacuum sintering furnace and sintering. 2. A plurality of electrode material-filled recesses lined up on the upper surface at predetermined intervals and a wire accommodating member formed so as to vertically cut through the electrode material-filled recesses. The wire for the lead wire is set by repeating the operation of setting the powdery electrode material filled in each of the electrode material filling concave portions with a pressing body while setting it in the wire accommodating groove of the die having the groove. On the other hand, the step of integrally forming the molded body of the capacitor element at a predetermined interval, the molded body of the capacitor element sent in a state of being connected to the lead wire is vacuumed at a predetermined length of the lead wire. Set in the sintering furnace and sinter, and after the above sintering, the capacitor element that is sent in the state of being connected to the lead wire. Continuously passed through a chemical conversion solution, the step of performing chemical conversion treatment, characterized in that it comprises a method for producing a solid electrolytic capacitor.