KR20030004663A - Method of manufacturing an aluminum solid electroyte capacitor - Google Patents

Abstract

PURPOSE: A method is provided to obtain an aluminum solid electrolytic capacitor with a high reliability and excellent quality by avoiding processes of applying stresses to the capacitor body. CONSTITUTION: A method comprises the steps of inserting a capacitor body into a case having a first aperture with an open bottom and a second aperture with a narrow top through the first aperture; performing sealing and fixing processes by using a sealant consisting of an epoxy resin; permitting the capacitor body to be coated or impregnated by introducing 3,4-ethylenedioxy-thiophene through the second aperture; and sealing the second aperture and generating a solid electrolyte made of poly(3,4-ethylenedioxy-thiophene) by an oxidative polymerization reaction.

Description

METHODS OF MANUFACTURING AN ALUMINUM SOLID ELECTROYTE CAPACITOR}

The present invention relates to a method for producing an aluminum solid electrolytic capacitor capable of mass-producing highly reliable products.

In general, aluminum electrolytic capacitors which are widely used are obtained by etching aluminum foil to enlarge the surface area, and chemically treating the aluminum foil to produce an oxide film. As a negative electrode foil, a liquid electrolyte is immersed in an element (hereinafter referred to as a "winding element") wound between a positive electrode foil and a negative electrode foil through a separator such as manila, and is completed. See -78287.

In recent years, aluminum solid electrolytic capacitors using a conductive polymer material as an electrolyte have been commercialized in the above-described aluminum electrolytic capacitor.

In the aluminum solid electrolytic capacitor, the solid electrolyte has higher electrical conductivity than the liquid electrolyte in the aluminum electrolytic capacitor, and therefore has less loss, and thus has characteristics such as excellent frequency characteristics and temperature characteristics.

However, unlike aluminum electrolytic capacitors, since there is no self-repairing action of the anodic oxide film, when a defect occurs in the anodic oxide film, there is a high possibility that the short circuit mode will be defective.

When a capacitor used in an electric device is short-circuited, an abnormal current flows and there is a risk of a fire occurring in the electric device. Therefore, in the aluminum solid electrolytic capacitor, the voltage of the anode oxide film is about three times higher than that of the aluminum electrolytic capacitor. This causes the capacity to be about one third.

By the way, when manufacturing an aluminum solid electrolytic capacitor by applying the prior art (for example, see Unexamined-Japanese-Patent No. 10-50558, Unexamined-Japanese-Patent No. 10-50560, etc.), after manufacturing a winding element, an anodic oxide film is produced. After the goods have been reassembled, they are assembled into a case and fixed.

7 is a flowchart for explaining a process of manufacturing a conventional aluminum solid electrolytic capacitor. First, in the first step, a wound element including an anode foil, a separator, and a cathode foil in which an oxide film is formed in the chemical conversion treatment is fabricated. In the second step, the oxide film of the anode foil is refired to repair defects. In the fourth step, heat treatment is performed. In the fifth step, a solid electrolyte is produced. In the sixth step, the solid electrolyte is assembled into the case. In the seventh step, the wound element and the case are bonded with an epoxy resin and cured. Is aged and inspected in the ninth process.

In the process of Fig. 7, even in the second process, the formation of the anodic oxide film is completed by recyclability, and thereafter, from the third process to the seventh process, i.e., from cleaning to assembly into the case. There is a problem that such a stress is applied to the wound element during the time to easily cause cracks in the anodic oxide film.

Specifically, when assembling the wound element in a case, the lead terminal of the wound element easily moves until it is adhesive cured with epoxy resin, and the wound element itself is soft and easily deformed by external force, so that the electrode foil is not stressed. Since it is difficult to handle and the anodization film is extremely thin at 1.3 (nm / V), even if great care is taken in each process, the defective rate is high, reaching 5 to 50%, and its reliability is low.

In the present invention, when manufacturing an aluminum solid electrolytic capacitor, by adopting a process sequence that can prevent the stress is applied to the capacitor body (for example, a wound element), by providing a means for enabling the process, It enables mass production of reliable and good quality aluminum solid electrolytic capacitors.

1 is a flowchart for explaining an example of the manufacturing process of the aluminum solid electrolytic capacitor according to the present invention.

Fig. 2 is a cutaway side view of an essential part showing an aluminum solid electrolytic capacitor at the stage where the third process is finished in the present invention.

Fig. 3 is an explanatory view of an essential part cutting side showing an aluminum solid electrolytic capacitor and a manufacturing apparatus at the point of the process;

Fig. 4 is an explanatory view of an essential part cutting side showing an aluminum solid electrolytic capacitor and a manufacturing apparatus at the point of the process;

Fig. 5 is a cut away side view of the main part of the capacitor and the capacitor mounting table in the drying process;

Fig. 6 is an explanatory view of a principal part showing a capacitor and a removal device for explaining a step of removing the second liquid filled in the second opening from the case;

7 is a flowchart for explaining a process of manufacturing a conventional aluminum solid electrolytic capacitor.

In the present invention, at the stage where the capacitor body is completed from the aluminum solid electrolytic capacitor, the assembly is immediately carried out in the case, the resin is bonded and cured, and the wound element is fixed at the initial stage of the process so that stress is applied to the anodic oxide film. In order to make it possible to perform such a process, the case with the opening which enables the implementation of various processing processes after bonding and hardening a lead terminal with resin in a winding element is essential, The case is disclosed in Japanese Patent Application Laid-Open No. 7-135116 (Japanese Patent Application Laid-Open No. Hei 8-78287).

1 is a flowchart for explaining an example of a process for producing an aluminum solid electrolytic capacitor according to the present invention. First, in the first step, a wound element including an anode foil, a separator, and a cathode foil having an oxide film formed by chemical conversion is fabricated, and in the second step, the wound element is assembled through a first opening in a case having a first opening and a second opening. In the third step, the wound element and the case are cured while adhering with the epoxy resin in the first opening. In the fourth step, the oxide film of the anode foil is refired to repair the defect, and the fifth step is cleaned. The heat treatment is performed, and the seventh step generates a solid electrolyte, is aged in the eighth step, the second opening is sealed in the ninth step, and the inspection is completed in the tenth step. In the aluminum fuselage electrolytic capacitor, the winding element described above and the electrode having a flat plate are mainly present. Therefore, a portion existing in the case including the above is called a "capacitor body", and in terms of its structure, the "capacitor body" Part of the lead terminal is also included.

As described above, according to the first embodiment of the present invention, a method of manufacturing an aluminum solid electrolytic capacitor

Fixing the capacitor body (eg, the capacitor body 1 of FIG. 2 to be described later) into a case having one or more openings (eg, the case 3 of FIG. 2 to be described later),

Introducing a raw material of a solid electrolyte from at least one of these openings and covering or immersing the capacitor body therein to induce an oxidative polymerization reaction.

One or more of the openings described above can be used as the introduction port when the capacitor body is disposed in the case. In this case, the size of the opening should be large enough to allow the capacitor body to pass through. However, this is not necessary if the capacitor body is placed in the case by other means.

As another role of the one or more openings described above, there are a role of evacuating air or gas from the inside of the case and an inlet when various liquids described below are introduced into the case. In this case, the opening should be as small as possible so that exhaust from the case can be made and the liquid can be introduced into the case. A plurality of such openings may be formed. The position where these openings are arranged is not limited to the end of the case as shown in Fig. 2 but may be the side surface of the case.

In the above description, "fixed" means that the capacitor body does not move freely in the case. As a material used for fixation, any material may be employed as long as it is non-conductive, and various kinds of resin materials may be used.

In particular, the use of liquid resin followed by solidification to fix the capacitor body and to seal the capacitor body in such a way that the inside of the case is divided into two zones by solidification is useful when introducing liquid using differential pressure. This will be explained later.

Preferably, in this case, the capacitor body is inserted into the case from the one or more openings (in the specification of the present application, for example, referred to as the first opening as in FIG. 2A of FIG. 2 to be described later).

In the step of fixing the capacitor body, sealing is performed at the same time as fixing.

The inside of the case is evacuated, and the raw material of the solid electrolyte uses openings other than the first opening of the one or more openings using differential pressure with the outside (in the specification of the present application, for example, 3B of FIG. And is introduced into this case which is exhausted through the second opening. This 2nd opening is corresponded to the opening for liquid introduction of one or more opening mentioned above.

In this way, for example, there is an advantage that the burden of subsequent cleaning is reduced by minimizing the deposition of the raw material of the solid electrolyte in the case, and there is a tendency that the raw material of the solid electrolyte is coated or immersed inside the capacitor body. By slowing and reducing due to the presence of, there is an advantage of achieving a reliable coating or dipping.

As to the formation position of the first opening, it is preferable to form a wide opening at one end of the case as shown in FIG. 2A of FIG. 2 described later to facilitate insertion of the capacitor body.

The formation position of the 2nd opening, ie, the opening for liquid introduction, is formed in the narrow shape at the edge part opposite to the 1st opening 3A like 3B of FIG. 2 mentioned later. When manufacturing the aluminum solid electrolytic capacitor according to the invention of the present application, it is necessary to turn over the case according to the state of the introduced liquid present in the interior of the case, the narrowed opening to easily prevent the liquid from spilling can do. It is preferable to form a collar part in the opening for liquid introduction as shown in FIG. 2C of FIG. 2 to be described later. This is because, depending on the material of the case, the final encapsulation of the opening can easily be made by thermal welding of this collar portion.

For the fixing and encapsulation described above, any material may be used as long as it is appropriate to the gist of the present invention. In particular, it is convenient to adopt a resin that has fluidity and loses fluidity in subsequent solidification.

Considering the degree of heat resistance and non-flowability of the solidified resin, the curable resin is preferred. For example, an epoxy resin, a phenol resin, a silicone resin, a fluororesin, a polyimide resin, or a modified body thereof can be employed. Among them, epoxy resins are particularly preferred in view of the variety of properties and reliability.

When using a cured resin such as an epoxy resin, in order to realize the fixing or encapsulation described above, it is often necessary to prevent (block) the flow of the liquid encapsulant by inserting a solid plate (called an encapsulant blocking member in this application) in advance. . A fixing ability can also be given to such an encapsulant blocking member.

In the present application, although the resin for fixing or encapsulation is called an encapsulant, the present application does not mean to be limited to the encapsulation, but also includes the use of the object and the object of fixation alone.

In the aluminum solid electrolytic capacitor according to the invention, a gap is preferably formed between the capacitor body and the second opening. This is because without this gap, the capacitor body closes the opening for liquid introduction. To this end, apart from properly selecting the position of the fixing or encapsulation of the capacitor body, it is effective to install a projection inside the case, which will be described later.

Further, after the capacitor body is coated or immersed with the raw material of the solid electrolyte, an oxidant for inducing an oxidative polymerization reaction of the raw material of the solid electrolyte is introduced through the second opening. Usually, when an oxidant coexists, the oxidative polymerization reaction by this invention advances gradually even at low temperature. Therefore, it is preferable to mix the raw material of a solid electrolyte and an oxidizing agent, and to introduce this mixture immediately thereafter. Instead of doing this, however, it has been found that there is no problem even if the capacitor body is previously coated or immersed with the raw material of the solid electrolyte, and then an oxidant for inducing the oxidative polymerization reaction of the solid electrolyte is introduced through the second opening. Even in this case, it is considered that the contact between the raw material of the solid electrolyte and the oxidizing agent is sufficient.

Preferably, the raw material of the solid electrolyte is 3, 4-ethylenedioxy-thiophene.

After the solid electrolyte is formed by the oxidation polymerization reaction or before the introduction of the raw material of the solid electrolyte, the capacitor body is sealed and fixed with an epoxy resin inside the case, and the aging is performed with the second opening open. It is also preferable to carry out the chemical conversion treatment by introducing a chemical liquid through the second opening followed by flowing a current through the + electrode.

It is also preferable to remove the oxidant present at least around the second opening after introducing the oxidant.

It is also preferable to apply ultrasonic vibrations when the raw material of the solid electrolyte is introduced into the case, when the raw material and the oxidant are introduced, when other liquids such as cleaning liquids are introduced, during chemical conversion treatment, during aging, and so on. This is thought to contribute to the removal of bubbles, the mixing of liquids, the reduction of empty spaces and the promotion of reactions. In particular, when the raw material and the oxidizing agent of the solid electrolyte are introduced, it is preferable to apply ultrasonic vibrations during chemical conversion or during aging.

In the washing step, the washing is effectively effected by repeating the depressurization and pressurization inside the tank to allow the washing liquid to enter the case and prevent its overflow, and then immersing the second opening in the tank holding the washing liquid.

Another feature of the invention is a capacitor body,

A case accommodating this capacitor body,

An encapsulant layer which fixes the capacitor body in this case and divides the inside of the case into two zones,

An encapsulant blocking member that prevents the encapsulant from penetrating into one of the compartments of the case and

There is an aluminum solid electrolytic capacitor comprising an opening formed in a region where penetration into the encapsulant is prevented and made of such a part.

As described above, since the capacitor body is protected from external forces in a very rigid case from the beginning, even if the handling is a little rough, there is no risk of a defect caused by stress on the oxide film of the + electrode, so that a highly reliable aluminum solid electrolytic capacitor Is realized.

Other objects, advantages and novel features of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings and tables.

(Example of the invention)

FIG. 2 is a cutaway side view of the main portion showing an aluminum solid electrolytic capacitor in a stage after the third process according to the present invention described with reference to FIG. 1, in which 1 is a capacitor body, 2 is a lead terminal, 3 is a case, 3A Is a first opening, 3B is a second opening, 3C is a collar portion, 4 is an adhesive blocking member, and 5 is an adhesive.

It is a matter of course that a conventional technique may be applied to produce a wound element, and one of the two lead terminals 2 shown is connected to the positive electrode foil and the other to the negative electrode foil, of course.

The adhesive blocking member 4 is inserted into the lead terminal 2 of the winding element, and it is inserted into the case 3 through the first opening 3A, and then wound by injecting and curing an adhesive 5 such as an epoxy resin. The element is fixed to the case 3 to complete the illustrated structure. Further, the adhesive blocking member 4 literally plays a role of preventing the adhesive 5 from flowing into the capacitor body 1 and the like, and also serves to position the wound element.

Thus, by fixing the wound element to the case 3 at the stage of the initial stage of the process, even if the lead terminal 2 is pressed, no stress is applied to the capacitor body 1, and the case is processed in a subsequent processing step. Even if (3) is retained, stress is not applied to the capacitor body 1. In this case, not only the case 3 is fixed but also the injection of this adhesive completely separates the two zones, that is, the opening 3B side and the opening 3A side, so that the air in the case is sucked from the opening 3A. When opened, only the opening 3A side is kept at a reduced pressure, that is, in a sealed state. In the present invention, "encapsulation of the capacitor body" is used in this sense. Hereinafter, the term "fixed" includes the concepts of "fixing" and "sealing" unless otherwise indicated or otherwise obvious in the context.

As a material of the case 3, a thermoplastic resin having a high dissolution temperature such as polyphenylene su1fide (PPS) resin is used, and the case temperature of the case 3 is made to withstand the solder reflow temperature of about 240 ° C. Similarly, an aluminum case having a structure having a first opening 3A and a second opening 3B may be used. In addition, the melting temperature of PPS resin is about 280 degreeC.

As the adhesive agent 5, it is necessary to maintain mechanical strength without deteriorating the adhesiveness with the lead terminal 2 or the case 3 through solder reflow, and a thermosetting epoxy resin is suitable for the purpose.

After the wound element is fixed to the case 3, the process flow shown in FIG. 1 undergoes each process of reoxidation-> cleaning-> heat treatment. It is necessary only when a defect does not occur in the anodic oxide film formed or a high production yield is required. Therefore, the description will be made later, and next, the production of the solid electrolyte will be described.

By the way, while introducing the substance for producing the solid electrolyte from the second opening 3B, the substance must be treated to be a solid electrolyte. However, since such a thing is not practiced in the past, technology is required for its implementation.

In this embodiment, 3, 4-ethylenedioxy-thiophene is used as the conductive polymer material in the solid electrolyte raw material, and p-toluenesulfonic acid iron (I1I) is used as the oxidizing agent, respectively.

3, 4-ethylenedioxy-thiophene has a high concentration and is difficult to handle. Thus, 3,4-ethylenedioxy-thiophene is dissolved in ethanol to give a 20 wt% solution to improve fluidity. In the following description, this liquid is referred to as the first liquid.

This first liquid must be introduced through the second opening 3B which is narrowly formed in consideration of the need to completely encapsulate the case 3 later. Therefore, a good result can be obtained by applying the vacuum dipping method.

3 and 4 are explanatory views of the main part cutting side showing the aluminum solid electrolytic capacitor and the manufacturing apparatus in the main process elements, and the same symbols as those used in FIG. 2 shall indicate the same parts or have the same meaning.

In the drawing, 2A is a positive lead terminal, 2B is a negative lead terminal, 10 is an aluminum solid electrolytic capacitor, 21 is a vacuum immersion tank, 22 is a first liquid introduction tube, 23 is a valve, 24 is an exhaust pipe, 25 is a check valve, 26 is a movable capacitor support member which also serves as a + supply voltage supply path, 27 is a cathode, 28 is a DC power supply, 29 is an ultrasonic transducer, 30 is an oscillator, 31 is a liquid temperature control unit, 32 is an electrolyte tank, 33 is a vacuum pump, 34 is The exhaust pipe, 35 denotes an external air supply pipe, 36 denotes the first liquid, 38 denotes a transparent cylinder whose bottom is blocked, and 39 denotes bubbles of air, respectively. In addition, the main body of the aluminum solid electrolytic capacitor manufacturing apparatus of the city is a vacuum immersion apparatus.

3 and 4, the manufacturing process of the aluminum solid electrolytic capacitor will be described.

See Figure 3

3- (1)

As shown, one end of the movable capacitor support member 26 extending out of the vacuum immersion tank 21 is sufficiently pressed down. In this state, the capacitor 10 is set in the vacuum immersion tank 21, but in this case, the opening 3C of the case 3 faces the bottom of the vacuum immersion tank 21, and the anode lead terminal ( It is immersed by connecting 2A) to the movable capacitor support member 26.

3- (2)

The valve 23 is opened, the required first liquid 36 is transferred from the tank 32 into the vacuum immersion tank 21, and the valve 23 is closed at the stage where the liquid level is kept at a predetermined height.

If the vacuum impregnation operation is performed continuously, the amount of the first liquid 36 transferred from the first liquid tank 32 into the vacuum immersion tank 21 is enough to supplement the consumption in the previous vacuum immersion operation.

In the state shown, since the movable capacitor support member 26 extending out of the vacuum immersion tank 21 is pressed down, the capacitor 10 is not yet in contact with the first liquid 36.

3- (3)

The liquid temperature control unit 31 is operated to maintain the liquid temperature of the first liquid 36 to be proper.

Normally, it is not necessary to control the temperature of the first liquid 36, but each process of recyclability for producing an oxide film on the anode immersion of the vacuum body and the capacitor body 1 has a relationship with the temperature of the first liquid 36. Therefore, it is better to control the temperature appropriate to the type.

3- (4)

In this state, the check valve 25 is changed to communicate with the vacuum pump 33 to block the inside of the vacuum immersion tank 21 from outside air, and the vacuum pump 33 is driven to exhaust the air.

Since the air pressure in the vacuum immersion tank 21 decreases, the air in the case 3 and the air in the bottomed cylinder 38 also expand and diffuse, and gradually exhaust.

At this time, the flow of air exhausted from the case 3 cannot be seen, but the air exhausted from the bottomed cylinder 38 in which the opening is immersed in the first liquid 36 with the bottom up is formed by bubbles 39 It can be visually recognized that the liquid passes through the first liquid 36. As the transparent bottomed cylinder 38, a test tube made of ordinary glass can be used.

When evacuation advances and bubbles do not appear from the bottomed cylinder 38, it may be determined that the air pressure in the vacuum immersion tank 21 maintains a constant value while reaching the target value.

See Figure 4

4- (1)

The portion extending out of the vacuum immersion tank 21 in the movable capacitor support member 26 is slightly restored, and the second opening 3B of the case 3 in the capacitor 10 is closed by the first liquid 36. ) In a locked state.

In this state, the first liquid 36 does not enter the case 3 or the bottomed cylindrical body 38.

4- (2)

By stopping the vacuum pump 33, the fresh air is slowly introduced into the vacuum immersion tank 21 by changing the check valve 25 so as to communicate with the external air supply pipe 35 only slightly.

In this way, the first liquid 36 gradually enters the case 3 and into the bottomed cylindrical body 38, and when the liquid level reaches the capacitor body 1, between the anode foil and the cathode foil. The first liquid 36 is sucked up by the capillary phenomenon by the separator made of insulating paper, and the liquid level of the capacitor main body 1 is higher than the liquid level in the case 3.

4- (3)

When the introduction of the outside air proceeds further and the pressure in the vacuum immersion tank 21 increases, the liquid level of the first liquid 36 further rises. In the figure, the state in which the first liquid 36 is immersed in the capacitor body 1 is shown.

4- (4)

When the introduction of the outside air is completed and the air pressure in the vacuum immersion tank 21 is at atmospheric pressure, the first liquid 36 is filled in the case 3 and the bottomed cylindrical body 38.

The amount of immersion of the first liquid 36 is determined depending on the type of capacitor, but in the case 3, about 60 (%) to about 70 (%) of the volume may be used. Therefore, the pressure reduction during vacuum immersion is 300 (hPa) to It may be about 400 (hPa).

The first liquid 36 is immersed in the capacitor 10 through the above-described process, and then the process of drying the immersed first liquid 36 should be performed. However, if the second opening 3B is placed downward, Since the first liquid 36 flows out, the second opening 3C must be kept facing upward. It should be noted that the operation of changing the position of the capacitor so that the second opening 3B faces upward can be performed with this opening 3B open. This is because if this operation is performed in a short time, there is no risk of spillage of the liquid.

Fig. 5 is a cutaway side view of the main part showing a capacitor and a mounting table of the capacitor in a drying process, and the same symbols as those used in Figs. 2 to 4 denote the same parts or have the same meaning.

In the figure, 40 is a mounting table, 40A is a recess for accommodating the lead terminals 2A and 2B of the capacitor, x is an upper surface of the capacitor body 1 and a wall surface on the side of the second opening 3B in the case 3, That is, the gap between the upper wall and the inner surface is shown.

The illustrated gap x constitutes a passage required for communicating with the outside via the second opening 3B, and at least 0.1 (mm) or more, preferably about 0.5 (mm) is required.

According to the market demand, it is necessary to make the external dimension as small as possible, and in the conventional capacitor, it is necessary to make the gap x zero. In the capacitor according to the present invention, however, the drying of the first liquid 30 is insufficient and the reliability is lowered. Thus, it is necessary to have the above-described gap x.

In order to maintain the above-described gap x, the upper surface of the capacitor body 1 is flush with the required gap x on the inner surface of the upper wall of the case 3 so that the upper surface of the capacitor body 1 does not directly contact the upper wall surface of the case 3. It is effective to install a projection.

Since the solvent of the 1st liquid 36 is ethanol, it is preferable to keep it at the temperature which does not exceed the boiling point 78.3 degreeC, for example, 70 degreeC, and to dry it, and the drying time of the capacitor and the size of the 2nd opening 3B Naturally, the case 3 has an external dimension of 3.6 (mm) x 3.6 (mm) x 6.3 (mm) to 4.6 (mm) x 4. It is 6 (mm) x 10.1 (mm), and when the diameter of the 2nd opening 3B is 0.8 (mm), it is 30 (minutes)-3 (hours).

After drying, the inner and outer surfaces of the capacitor main body 1 are covered with a film of monomers of the conductive polymer material. Therefore, an oxidizing agent must be mixed to generate an oxidative polymerization reaction to generate a solid electrolyte.

In this embodiment, as described above, p-toluene iron sulfonate (III) is used as the oxidizing agent, and n-butyl alcohol (dissolved in boiling point (117.7 ° C.) is used as a 50 (wt%) solution. This liquid will be called the second liquid.

Vacuum immersion is optimal for introducing the second liquid into the capacitor body 1 in the case 3. In order to do this, the same means as the vacuum immersion of the first liquid may be used, but it is important not to create an empty space in the capacitor main body 1 that lacks the second liquid, and therefore, in the case of the first liquid Compared to the pressure reduction, it is preferable to reduce the pressure to about 100 (hPa).

Therefore, immediately after vacuum immersing the second liquid, the case 3 is filled with the second liquid, including the second opening 3B, and thus the second opening 3B is filled with the second liquid. If it is, it is difficult to dry.

FIG. 6 is an explanatory view of principal parts showing a capacitor and a removal device for explaining a process of removing the second liquid filled in the second opening from the case, and the same symbols as those used in FIGS. Denote or have the same meaning.

In the figure, 41 denotes a compressed air supply pipe, 42 denotes a nozzle, 51 denotes a second liquid, and 51A denotes a second liquid that flies away.

As is apparent from the figure, the capacitor 10 is placed upright, and compressed air is blown out from the nozzle 42 to blow off the second liquid 51 present near the second opening 3B and exhaust it. At this time, the second liquid attached to the outside of the case 3 can also be removed at the same time.

Since the second liquid exhausted from the second opening 3B is the remaining liquid between the capacitor body 1 and the case 3, the exhaust does not affect the characteristics of the capacitor.

Since the monomer constituting the first liquid is immersed in the capacitor body 1 by diluting ethanol with good interface and wettability, the ethanol evaporates after entering the fine pores on the surface of the anode foil, and the surface of the monomer is thin. Since the film remains and the second liquid is immersed therein, the mixing of the monomer and the second liquid is naturally performed, but it is effective when ultrasonic vibration is applied to further promote the mixing, thereby reducing the variation in quality. can do.

Immediately after the second liquid is immersed, the 3,4-ethylenedioxy-thiophene is slowly reacted by the action of p-toluene iron sulfonate (III), and as shown in FIG. 10) is kept upright so that the 2nd opening 3B may hold | maintain a stomach, and the following heat processing performs oxidation polymerization and the drying of the solvent which becomes n-butyl alcohol.

Stage 1

Treatment temperature: 50 degrees Celsius

Processing time: 3 (hours)

2nd Stage

Treatment temperature: 60 (℃)

Processing time: 3 (hours)

Third Stage

Treatment temperature: 80 ℃

Processing time: 10 (hours)-30 (hours)

4th Stage

Treatment temperature: 125 degrees Celsius

Processing time: 2 (hours)

5th Stage

Treatment temperature: 150 degrees Celsius

Processing time: 1 hour

The processing time of the heat treatment performed by applying the temperature of 80 ° C. may be selected according to specifications such as the size of the capacitor.

When the heat treatment at a temperature of 150 ° C. is completed, the oxidative polymerization of 3,4-ethylenedioxy-thiophene is completed and becomes polyethylenedioxy-thiophene. However, in the present invention, the heat treatment at a temperature of 125 ° C. and a temperature of 150 ° C. Significantly good effects are obtained by applying voltage at the stage subjected to the heat treatment at (° C), that is, at the stage before sealing the second opening 3B and aging. In the present invention, "aging" means applying a voltage between the electrodes of the capacitor while heating. In this heating, the temperature around the capacitor is 85 ° C to 165 ° C to promote aging. As mentioned above, this heating can also be used as heat treatment. Too high a heating temperature is undesirable since it causes deterioration of performance. In addition, the voltage to be applied is a DC voltage and preferably 1.1 to 2.0 times the rated voltage ratio. Too low is not preferable because the reliability of the production is inferior. In addition, even if too high, it is not preferable because it degrades insulation characteristics. In addition, for the reasons described below, it is preferable that some moisture is present in the capacitor.

It is well known that "aging" is used in the field of ordinary aluminum electrolytic capacitors in the sense of "rePair", and in the aluminum solid electrolytic capacitor, there is basically no repair action of an oxide film such as an electrolytic capacitor. .

However, through experiments, a small leakage current is observed after a long time by applying a voltage load to the finished aluminum solid electrolytic capacitor at high temperature.

It is considered that this is because the aluminum expressed on the defective portion of the positive electrode foil is oxidized by oxygen generated by the slight moisture contained in the capacitor by electrolysis due to leakage current, and therefore aging is also effective in an aluminum solid electrolytic capacitor.

However, the aging is essential after the capacitor main body 1 is fixed to the case 3, and if the aging is performed while the capacitor main body 1 is not fixed to the case 3, subsequent steps Inevitably a stress is applied to the capacitor body 1, so that aging is likely to be useless.

Even in the prior art (see, for example, Japanese Unexamined Patent Publications Nos. 10-50558, 10-50560, etc.), after fixing, in order to avoid the problem of aging without fixing the capacitor body in the case, Processing is as shown in FIG.

However, in the related art, it is the same as sealing the case, that is, sealing the capacitor body by using epoxy resin to fix the case to the case. In this state, the moisture is insufficient. It is not enough.

In contrast, in the present invention, aging can be performed simultaneously in the heat treatment stage before the second opening 3B is sealed, in which the capacitor main body 1 is already fixed to the case 3, and the case 3 ) Can be aged in a state where there is enough water to sufficiently achieve the effect of aging, and thereafter, excess water can be sufficiently sealed through the second opening 3B.

In the present invention, the case 3 was sealed, that is, the second opening 3B was sealed, and then the aging process was experimented. However, in the state in which the heat treatment for oxidative polymerization and solvent drying is completed, both the solvent and the moisture are evaporated. Therefore, although the effect of aging is inadequate, it does not interfere even if it implements if necessary.

As described above, in the present invention, the steps of the recyclability-> cleaning-> heat treatment shown in FIG. 1 are not essential, but performing these steps is preferable for improving the characteristics of the capacitor. Therefore, the implementation is described below.

In both the case of a normal aluminum electrolytic capacitor and an aluminum solid electrolytic capacitor, the anode foil is subjected to etching to increase the surface area, and to carry out a chemical conversion current in a chemical solution to produce an oxide film. In this case, productivity is improved by processing continuously, taking out the aluminum foil wound on the wide roll.

Therefore, in order to manufacture a wound element, it is necessary to cut | disconnect aluminum foil narrowly and shortly. Therefore, the oxide film does not exist in the cut surface. In addition, since the lead terminal must be connected to the electrode foil thus produced, the oxide film is often damaged during the process.

In the case of a normal aluminum electrolytic capacitor, that is, a capacitor using an electrolytic solution, the electrolytic solution has a strong self-healing ability, and thus it is possible to repair damage to the oxide film in the aging step after assembly. However, in the case of an aluminum solid electrolytic capacitor, it is basically incapable of self-repairing ability, and it is preferable to repair the defective part of an oxide film | membrane on the cutting surface of electrode foil etc. by recyclability.

As a standard chemical solution, 0.1 (g) of phosphoric acid is dissolved in 1 (liter) of an aqueous solution of 2 (wt%) to 3 (wt%) aqueous solution of ammonium adiPate. However, besides this, various things, such as aqueous solution of ammonium borate, are used, and these are selected according to the chemical | voltage conversion voltage and the kind of electrode foil, and since the temperature of chemical liquid also affects the characteristic of an oxide film, it is necessary to control to fixed temperature. .

As the reoxidation process proceeds, the oxide film grows and the chemical current gradually decreases. In the process, ultrasonic vibration is applied to improve contact between the chemical liquid and the oxide film so that even a small defect portion can be repaired.

As is apparent from Fig. 7, in the conventional manufacturing process, the reprocessing process is performed in a state in which the wound element is not accommodated in the case, so that the immersion and washing of the chemical solution are easy, however, no matter how adopted Even if an excellent oxide film is formed, there is little resistance to external force until it is accommodated in the case and fixed. Therefore, even if great care is taken during the subsequent process, it is impossible to work without applying stress to the wound element.

For example, when the lead wire is picked up and moved, a stress is applied to the electrode foil to which the lead terminal is connected, and a stress is applied to the electrode foil simply by placing the wound element on the tray. Nothing.

Also in the present invention, although each process of the recyclability-> cleaning-> heat treatment shown in FIG. 1 can be performed in the state of a winding element, it is the thing which stress is applied to an oxide film in the case of carrying out case assembly and epoxy resin adhesion hardening. can not avoid.

Therefore, in the present invention, when the reprocessing process is carried out, the winding element 1 is fixed to the case 3, and at this time, the second opening 3B which is small in order to ensure the final sealing surely and easily. It should be done through For this purpose, the same means as in the case of vacuum immersion of the first liquid and the second liquid described above may be adopted.

That is, by converting the first liquid or the second liquid described with reference to FIGS. 3 and 4 into a chemical liquid, the reprocessing treatment can be performed in almost the same process, and the operation of the illustrated manufacturing apparatus and the like are almost the same. Some supplementary explanation is required.

In the vacuum immersion tank 21 shown in FIG. 3, the 2nd opening 3B of the case 3 is hold | maintained from the liquid level, the vacuum pump 33 is operated, and the inside of the immersion tank 21 is exhausted. At this time, the gas in the case 3 is also exhausted through the second opening 3B.

As shown in Fig. 4, in the case 3, the second opening 3B is inserted into the chemical liquid and the outside air is introduced into the vacuum immersion tank 21 to fill the chemical liquid in the case 3. Is authorized.

When the positive voltage of the chemical voltage is applied to the positive electrode foil and the negative voltage is applied to the negative electrode 27 provided by dipping in the chemical liquid, the chemical current flows from the positive electrode foil to the negative electrode 27 through the second opening 3B. The lead terminal 2A of the capacitor 10 is connected to the positive electrode foil.

As described above, when the chemical current flows, water is electrolyzed to generate oxygen in the anode foil to oxidize aluminum to form an aluminum oxide film, and hydrogen is generated in the cathode 27 to be discharged into the immersion tank 21. In this case, the temperature of the chemical liquid is closely related to the characteristics of the chemical film, that is, the oxide film, and it is necessary to control the temperature so that the temperature is always a constant temperature.

During regeneration, the ultrasonic transducer 29 and the vibrator 30 shown in FIG. 4 are operated, and ultrasonic vibration is applied to the positive electrode foil through the chemical liquid to promote the regeneration.

The time to refire is about 10 (60) minutes, but if necessary, it may repeat after each process of washing | cleaning, drying, and heat processing which continue after that is complete.

When the recyclability is finished, the chemical liquid is removed from the case 3, washed and dried.

In the prior art, when the process is performed as a wound element, it may be immersed in a flow of pure water for a predetermined time, for example, about 10 (30) to 30 (minute), but in the case of the present invention, the case ( Since the capacitor main body 1 is fixed in 3), since it cannot wash only by immersing in flowing water, the means demonstrated below may be employ | adopted.

As shown in FIG. 3, when the capacitor 10 is held down in the vacuum immersion tank 21 and the second opening 3B is kept down and the vacuum pump 33 is operated to depressurize, the chemical liquid in the case 3 It exhausts from the 2nd opening 3B.

In this case, if the decompression is large, the amount of exhaust gas of the chemical liquid is large. However, when a plurality of processes are processed simultaneously, fluctuations occur in the exhaust gas, so that the pressure may be reduced twice. Atmospheric pressure (1013 (hPa)) → reduced pressure (100 (hPa) to 200 (hPa)) → atmospheric pressure (1013 (hPa)) → reduced pressure (100 (hPa) to 200 (hPa)) → atmospheric pressure (1013 (hPa)) to be.

By going through the above process, the recyclable liquid between the case 3 and the capacitor main body 1 is exhausted, but since the capacitor main body still remains wet with the chemical liquid, it is necessary to clean it afterwards.

If the liquid shown in Fig. 4 is used as the cleaning liquid and the second opening 3B is inserted into the cleaning liquid, and the decompression / restoration of atmospheric pressure is repeated, the cleaning liquid in the case 3 is decompressed when the pressure is reduced. Since the cleaning liquid is pushed out through the 3B and released into the case 3 through the second opening 3B when released to the atmosphere, the cleaning liquid functions like the flowing water.

The pressure is about 200 (hPa) to 300 (hPa), and even when the cleaning liquid is pushed into the case 3 by releasing the atmosphere, the cleaning liquid circulates satisfactorily if bubbles remain in the case 3.

Any cleaning liquid can be used as long as it is capable of eluting the chemical liquid, but in general, pure water is optimal, and the temperature of the cleaning liquid is related to the cleaning speed, and the cleaning liquid can be maintained at about 40 (C) to 80 (C). In addition, in the case of cleaning, if ultrasonic vibration is employed, the cleaning effect is promoted. In addition, in order to exhaust the cleaning liquid in the case 3, the same means as the exhaust of the chemical liquid may be adopted.

With the cleaning liquid exhausted in the case 3, the capacitor body 1 remains wet and heated and dried. The drying can be performed in combination with a heat treatment for reforming the chemical film or a heat treatment for reforming the insulating paper. Although heat treatment conditions change according to the objective, generally, temperature is 100 (degreeC)-270 (degreeC) and time is about 10 (minutes)-about 60 (minutes).

In each of the above processes, one cycle of the reprocessing process is completed. As described above, since the aluminum solid electrolytic capacitor does not have the self-repairing capability of the oxide film, it is reliable to form a high quality oxide film before producing the solid electrolyte. In order to realize a highly reliable aluminum and solid electrolytic capacitor, it is desirable to repeat the reprocessing process over a plurality of cycles, because it is very important for improvement.

Normally at the end of the operation all the openings are sealed. In the case of the opening B, it is effectively sealed by resin.

Example

The wound element was bonded and cured with an epoxy resin to a case 3 having an external dimension of 3.6 mm x 3.6 mm x 9.8 mm, and two cycles of recyclability were carried out by means described above. The solution obtained by dissolving 20% (%) of dioxy-thiophene in ethanol was immersed in the above-described means and dried, and the solid electrolyte was immersed in a solution of 50% (%) of iron p-toluenesulfonate dissolved in n-butyl alcohol. 60 samples were produced.

All samples were measured, resulting in three failures because the equivalent serial resistance (ESR) of 100 (kHz) exceeded 150 (mΩ), and the remaining 57 were good products. .

After randomly selecting ten of the superior products and performing reflow soldering, a life test was performed at a temperature of 105 ° C while applying a rated voltage of 6.3 (V), and the following data were obtained. In this way, it turns out that it has extremely stable performance. The data are also averages of ten.

The present invention is not limited to the drawings, the tables, the production examples, and the others described herein, and various changes can be made without departing from the scope of the claims.

For example, in the said Example, although the winding element was used in the capacitor main body through the separator between the anode foil and the cathode foil, a flat aluminum electrode can also be used for the anode and the cathode.

In the above embodiment, in order to produce a solid electrolyte, 3, 4-ethylenedioxy-thiophene, which is a conductive polymer material, is dissolved in a solvent, and p-toluene iron sulfonate (I11), which is an oxidizing agent, is dissolved in another solvent. Although dipping in two times, the solution which mixed the conductive polymer material and the oxidizing agent can be made, and can be finished by only one dipping.

In this case, although there is an advantage in that the process is reduced, the mixed solution is gentle but the polymerization reaction proceeds, so it cannot be stored and should be prepared each time just before immersion, and the container in contact with the mixed solution. Needs to be washed every time, and the utilization rate of expensive raw materials is not good.

On the other hand, in the case where the means for immersing the first liquid and the second liquid described in the above embodiments are employed, there is no risk of deterioration as long as care is taken not to mix the two liquids. %) Although it can use effectively, what kind of means should be selected as needed. As described above, in the case where the positive electrode and the negative electrode are formed in a flat plate shape, the apparatus shown in Figs. 3 and 4 is used in the same manner as described above, but the solution is deposited in a state close to the application rather than in the state of immersion.

Examples of the conductive polymer material include the 3,4-ethylenedioxy-thiophene, pyrrole, furan, aniline, acene, acetylene, and thiophenol as exemplified in the examples, but the 3,4-ethylenedioxy- Thiophene is particularly preferred.

By adopting the manufacturing method of the aluminum solid electrolytic capacitor according to the present invention, and providing a component manufactured by the configuration according to the present invention, since the capacitor body is protected from external forces from a high rigidity case from the beginning, the roughness of the + electrode There is no risk of defects caused by stress being applied to the oxide film. Therefore, a highly reliable aluminum solid electrolytic capacitor can be realized. In addition, according to the embodiment of the present invention, it is also an advantage that the manufacturing operation is more rationally performed. In particular, operations of liquid introduction and cleaning using differential pressures can be reasonably performed, and are particularly useful for the production of aluminum solid electrolytic capacitors in which product quality deterioration occurs even with a very small degree of stress.

The main advantage to mention further is the quality and yield of the final product. This advantage is not only due to the fact that the capacitor body is fixed and protected, but the manufacturing method according to the invention of the present application performs stably with accompanying oxidative polymerization reaction, chemical conversion treatment and high regenerative aging treatment while reducing stress as much as possible. It is possible by doing this.

Advantages of the invention of the present application in the manufacture of aluminum solid electrolytic capacitors include a capacitor body, a case for accommodating the capacitor body, an encapsulant for fixing the capacitor body in the case and dividing the inside of the case into two zones, the encapsulating agent of which It can be particularly effectively achieved by having a component comprising an encapsulant blocking member that does not penetrate into one of the zones of the case and an opening formed in the zone where penetration into the encapsulant is prevented and thus produced It can be seen that aluminum solid electrolytic capacitors have high quality stability.

According to the present invention, by manufacturing an aluminum solid electrolytic capacitor, by adopting a process sequence which can prevent stress from being applied to the capacitor body (for example, a wound element), and providing a means for enabling the process to be carried out. In addition, it is possible to mass-produce aluminum solid electrolytic capacitors with high reliability and good quality.

Claims (14)

Securing the capacitor body in a case having one or more openings, Introducing a raw material of a solid electrolyte from at least one of these openings and covering or immersing the capacitor body therein to induce an oxidative polymerization reaction. The method of claim 1, The capacitor body is inserted into the case from one of the one or more openings (first openings), In the step of fixing the capacitor body, the encapsulation is made with the fixing, Aluminum into which the inside of the case is exhausted and the raw material of the solid electrolyte is introduced by using a differential pressure with the outside to the case where the exhaust is exhausted through an opening (second opening) other than the first opening of the at least one opening. Method of making a solid electrolytic capacitor. The method of claim 2, A method for producing an aluminum solid electrolytic capacitor using an epoxy resin for the encapsulation. The method of claim 2, A method of manufacturing an aluminum solid electrolytic capacitor in which a gap is formed between the capacitor body and the second opening. The method of claim 2, A method for producing an aluminum solid electrolytic capacitor, in which an oxidizing agent is introduced through a second opening to induce an oxidative polymerization reaction of a raw material of a solid electrolyte after the capacitor body is immersed or coated in the raw material of a solid electrolyte. The method of claim 2, After producing a solid electrolyte by an oxidative polymerization reaction, the manufacturing method of the aluminum solid electrolytic capacitor which performs aging, performing drying in the state which opened the 2nd opening. The method of claim 2, After encapsulating and fixing the capacitor body in the case using an epoxy resin prior to the introduction of the raw material of the solid electrolyte, a chemical conversion treatment is performed by introducing a chemical liquid through the second opening and applying a current to the + electrode, followed by washing and Method for the production of aluminum solid electrolytic capacitors to carry out drying. The method of claim 2, The raw material of the solid electrolyte is 3, 4-ethylenedioxy-thiophene manufacturing method of aluminum solid electrolytic capacitors. The method of claim 5, A method for producing an aluminum solid electrolytic capacitor, after removing the oxidant, at least the oxidant in the vicinity of the second opening is removed. The method of claim 5, A method for producing an aluminum solid electrolytic capacitor which promotes mixing by applying ultrasonic vibrations after introducing a raw material of a solid electrolyte and an oxidizing agent. The method of claim 7, wherein Method for producing an aluminum solid electrolytic capacitor, which is subjected to ultrasonic vibrations during chemical conversion. The method of claim 7, wherein A method for producing an aluminum solid electrolytic capacitor, wherein the second opening is immersed in a tank containing the cleaning liquid, the cleaning liquid is introduced and discharged, and the cleaning in the case is performed by repeating the pressure reduction and pressurization in the tank. Capacitor body, A case accommodating this capacitor body, An encapsulant layer which fixes the capacitor body in this case and divides the inside of the case into two zones, An encapsulant blocking member that prevents the encapsulant from penetrating into one of the compartments of the case and An aluminum solid electrolytic capacitor component comprising an opening formed in a region where penetration into the encapsulant is prevented. An aluminum solid electrolytic capacitor manufactured from the aluminum solid electrolytic capacitor component of claim 13.