JP2002064035A - Laminated solid electrolytic capacitor having through hole in cathode foil, anode foil and supporting board, and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated solid electrolytic capacitor which is excellent in high-frequency characteristic and large in storage capacity, and is of large flat board, and its manufacturing method. SOLUTION: A cathode electrode foil 2 having through holes and an anode electrode foil 1 of which surface is covered with a dielectric oxidized film and which has through holes are laminated with a separator 3 in between, thereby forming a capacitor element 10. A plurality of capacitor elements 10 are laminated, and a supporting board having through holes is arranged at least on one side of the laminated body, and then the separator is impregnated with a 3,4-ethylenedioxithiophene monomer and an oxidizing agent. It is heated and pressurized to polymerize the monomer, resulting in a solid electrolytic layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large flat solid electrolytic capacitor and a method for manufacturing the same, and more particularly to a solid electrolytic capacitor using a conductive organic solid electrolyte.

[0002]

2. Description of the Related Art An electrolytic capacitor is formed by forming an oxide film layer serving as a dielectric on the surface of an anode electrode made of a valve metal such as tantalum and aluminum and having fine holes and etching pits. Is drawn out.

[0003] The extraction of the electrode from the oxide film layer is performed by a conductive electrolyte layer. Therefore, in the electrolytic capacitor, the electrolyte layer serves as a true cathode. For example, in an aluminum electrolytic capacitor, a liquid electrolyte is used as a true electrode, and a cathode electrode merely serves to electrically connect the liquid electrolyte layer to an external terminal.

[0004] The electrolyte layer functioning as a true cathode is required to have adhesion, denseness, uniformity, etc. with the oxide film layer.
In particular, the adhesion in the fine holes of the anode electrode and the inside of the etching pits has a great effect on the electrical characteristics, and a number of electrolyte layers have been proposed.

[0005] A solid electrolytic capacitor uses a solid electrolyte having conductivity instead of a liquid electrolyte layer lacking impedance characteristics in a high-frequency region because of its ionic conductivity. ,
7,8,8-Tetracyanoquinodimethane (TCNQ) complexes are known.

[0006] The solid electrolyte layer made of manganese dioxide is
An anode element made of a sintered body of tantalum is immersed in an aqueous solution of manganese nitrate, and is produced by thermal decomposition at a temperature of about 300 to 400 ° C. In a capacitor using such a solid electrolyte layer, the oxide film layer is easily damaged at the time of thermal decomposition of manganese nitrate, and therefore, a tendency for the leakage current to increase is observed. Further, since the specific resistance of manganese dioxide itself is high, it is also difficult to obtain sufficiently satisfactory characteristics in impedance characteristics. In addition, since the lead wire is damaged by the heat treatment, it is necessary to separately provide an external terminal for connection as a later process.

As a solid electrolytic capacitor using a TCNQ complex, one disclosed in Japanese Patent Application Laid-Open No. 58-191414 is known. An electrolyte layer is formed. This TCNQ complex has high conductivity and can obtain good results in frequency characteristics and temperature characteristics.

However, since the TCNQ complex has a property of being transferred to an insulator in a short time after melting, it is difficult to control the temperature during the manufacturing process of the capacitor. Furthermore, since the TCNQ complex itself lacks heat resistance, when mounted on a printed circuit board, remarkable fluctuations in characteristics due to solder heat are observed.

In order to solve the disadvantages of the manganese dioxide and TCNQ complex, attempts have been made to use a conductive polymer such as polypyrrole as the solid electrolyte layer.

[0010] The conductive polymer represented by polypyrrole is mainly produced by a chemical oxidation polymerization method (chemical polymerization) or an electrolytic oxidation polymerization method (electrolytic polymerization). However, it was difficult to form a strong film densely by chemical polymerization. On the other hand, in the electrolytic polymerization, it is necessary to apply a voltage to an object to form a film, and it is difficult to apply the voltage to an anode electrode for an electrolytic capacitor having an oxide film layer as an insulator formed on the surface. Therefore, on the surface of the oxide film layer, a conductive pre-coat layer, for example, a pre-coat layer of a conductive polymer film chemically polymerized using an oxidizing agent is formed in advance, and then an electrolyte layer by electrolytic polymerization using the pre-coat layer as an electrode. There has been proposed a method of forming the film (Japanese Patent Laid-Open No. 63-1).
No. 73313, JP-A-63-158829:
Manganese dioxide is used as the precoat layer).

However, in the electrolytic polymerization, the step of forming the pre-coat layer is required in advance, which complicates the manufacturing process. In addition, the solid electrolyte is placed near the external electrode for polymerization disposed on the surface of the anode electrode to be coated. Since the layer is formed, it is very difficult to continuously form a conductive polymer film having a uniform thickness over a wide range.

Therefore, a foil-like anode electrode and a cathode electrode are
Winding through a separator to form a so-called winding type capacitor element, this capacitor element is impregnated with a monomer solution such as pyrrole and an oxidizing agent, and an electrolyte layer consisting of a conductive polymer film formed only by chemical polymerization Has been attempted.

[0013] Such a wound type capacitor element is well known for an aluminum electrolytic capacitor. By holding a conductive polymer layer with a separator, it is possible to avoid the complication of electrolytic polymerization and also to increase the surface area. It was expected that the capacity would be expanded by the foil-like electrode.

However, when a capacitor element is impregnated with a mixed solution obtained by mixing a monomer solution and an oxidizing agent, a solid electrolyte layer is not formed inside the capacitor element, and the expected electrical characteristics cannot be obtained. There was found.

Therefore, a method of separately impregnating the monomer solution and the oxidizing agent, a method of lowering the polymerization reaction temperature, and the like have been tried, and a solid electrolytic capacitor having somewhat good electrical characteristics has been obtained. However, there remains a problem that the impedance is not high enough and the impedance becomes high. The cause is that in the above method, the solid electrolyte layer generated near the end of the capacitor element hinders the penetration of the solution into the inside of the capacitor element, and as a result, it has not been possible to form a dense and uniform solid electrolyte layer It was considered possible. In addition, when the polymerization reaction temperature is lowered, strict temperature control is required, and the production apparatus becomes complicated, resulting in a problem that the product cost is increased.

The present inventors have repeatedly studied various conductive polymers, and focused on polyethylene dioxythiophene, which has a slow reaction rate and excellent adhesion to the oxide film layer of the anode electrode ( As a result, a capacitor element in which an anode electrode foil and a cathode electrode foil are wound through a separator is impregnated with 3,4-ethylenedioxythiophene and an oxidizing agent. We have applied for an invention characterized in that polyethylene dioxythiophene, which is a solid electrolyte, is generated inside a capacitor element by a chemical polymerization reaction of the monomer and an oxidizing agent which proceeds slowly (Japanese Patent Application No. 8-131374). According to the present invention, it is possible to generate a solid electrolyte layer made of a dense and uniform conductive polymer inside a spirally wound capacitor element, utilizing the fact that the polymerization reaction rate of polyethylene dioxythiophene is slow. Thus, a solid electrolytic capacitor having excellent electric characteristics and a relatively high capacity was obtained.

[0017]

However, all of the electrolytic capacitor elements having the above-mentioned structure are required to have high withstand voltage, high capacitance and flattening due to the recent advancement of the functions of the circuit, and are more excellent. It has not been able to meet the demand for having high frequency characteristics. For example, in the case of a wound-type capacitor element, it is necessary to increase the number of windings in order to satisfy a high capacity requirement, but it is difficult to store it compactly because of its cylindrical shape.

Further, when the capacitor element is of a wound type, there is a suggestion that the closing force of the capacitor element contributes to the adhesion between the bipolar electrode and the solid electrolyte layer. It is difficult to make the tightening force for winding and closing the separator uniform, and it is also difficult to adjust this tightening force. For this reason, the efficiency of adhesion is not improved, and sufficient capacitance has not been obtained.

At present, in a multilayer solid electrolytic capacitor, it has not been possible to simultaneously satisfy all the demands for high capacity, high withstand voltage, flattening, and excellent high frequency characteristics. The cause is that when the thickness of the dielectric film of the anode foil is increased to satisfy the high withstand voltage requirement, the obtained capacitance is reduced. In order to compensate for the capacitance, it is necessary to increase the area of the dielectric film of the anode foil. Therefore, if the shape of the multilayer capacitor is simply enlarged to satisfy this high capacity requirement, the solid electrolyte layer generated near the end of the capacitor element will hinder the penetration of the solution into the capacitor element, Cannot be sufficiently penetrated uniformly. As a result, a dense and uniform solid electrolyte layer cannot be formed, and it becomes difficult to adhere both electrode foils to the conductive polymer, which causes a problem that a sufficient capacitance cannot be obtained.

An object of the present invention is to solve the above-mentioned problems, to improve impedance characteristics, to provide high withstand voltage and high frequency characteristics, to have a large capacitance, and to easily store a large-sized laminated solid. An electrolytic capacitor and a method for manufacturing the same are provided.

[0021]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a capacitor element comprising a cathode electrode foil having a through-hole and an anode electrode foil having a dielectric oxide film formed on the surface and having a through-hole interposed therebetween through a separator. And stacking a plurality of this element,
After disposing a support plate having a through hole on at least one side of the obtained laminate, the separator is impregnated with a 3,4-ethylenedioxythiophene monomer and an oxidizing agent, and heated under pressure to polymerize the monomer. This is achieved by a large-sized flat-plate laminated solid electrolytic capacitor characterized by having high withstand voltage, high capacitance, and excellent high-frequency characteristics.

In this electrolytic capacitor, a capacitor element is obtained by laminating a cathode electrode foil having a through hole and an anode electrode foil having a dielectric oxide film formed on the surface and having a through hole via a separator. After arranging a support plate having a through hole on at least one side of the obtained laminate, the separator is impregnated with a 3,4-ethylenedioxythiophene monomer and an oxidizing agent, Is heated under pressure to polymerize the monomer, re-form under high-humidity conditions at normal temperature or higher, and remove water to produce the monomer.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The anode electrode foil may be made of any valve metal such as aluminum or tantalum, but aluminum is usually used. A voltage is applied to the surface of the anode electrode foil in an aqueous solution of ammonium borate or the like to form an oxide film layer serving as a dielectric, thereby forming through holes.

The area ratio occupied by the through holes in the anode foil is 1
~ 50%, particularly preferably 10-30%. If the area ratio of the through holes is less than 1%, the low frequency characteristics deteriorate. On the other hand, if the area of the through hole is larger than 50%, the surface area of the anode foil is reduced, and the capacitance is reduced. Further, the distance between the through holes is preferably 1 to 5 mm. The shape of the through hole is
It is arbitrary such as a circle and a rectangle, and its size is usually 1-2.
0 mm ² .

The cathode electrode foil may be any material that electrically connects the lead wire and the electrolyte. In one embodiment of the present invention, a through hole is formed using aluminum or the like. It is preferable to form a titanium nitride film on the surface of the cathode electrode foil because the capacitance increases.

The area ratio occupied by the through holes in the cathode foil is 1
~ 50%, particularly preferably 10-30%. If the area ratio of the through-holes is less than 1%, the effect of forming the through-holes does not sufficiently exhibit the moisture penetration effect, and the high withstand voltage cannot be achieved. On the other hand, if the area of the through hole is larger than 50%, the area of the cathode foil in contact with the solid electrolyte layer is reduced, so that the capacitance is reduced. That is, the high frequency characteristics deteriorate.
Further, the distance between the through holes is preferably 1 to 5 mm. If the distance between the through holes is less than 1 mm, the strength of the cathode foil decreases,
If it is larger than mm, the moisture penetration effect due to the formation of the through hole is not sufficiently exhibited. The shape of the through hole is circular,
It is arbitrary such as a rectangle, and its size is usually 1 to 20 mm
² .

Lead wires for connecting the respective electrodes to the outside are connected to the anode electrode foil and the cathode electrode foil by known means such as stitching and ultrasonic welding. The lead wire is made of aluminum or the like, and is composed of a connection portion with the anode electrode foil and the cathode electrode foil and an external connection portion that performs an electrical connection with the outside, and is led out from an end of the laminated capacitor element.

The anode electrode foil and the cathode electrode foil are subjected to repair formation in a chemical conversion solution and then immersed in a boric acid aqueous solution in order to repair a damaged portion or a cut surface of the film received in the processing step. This stabilizes the oxide film and increases the high withstand voltage.

Although a glass separator is usually used as the separator, as another embodiment, electrolytic paper used for a general electrolytic capacitor can be used. In other words, synthetic fibers, those made by mixing these,
Further, a nonwoven fabric obtained by mixing synthetic fibers and fibers for electrolytic paper or glass fibers can be used. Examples of the synthetic fiber include vinylon fiber, polyester fiber, nylon fiber, rayon fiber and the like. Furthermore, a synthetic resin porous separator can be used. Examples of these synthetic resins include polyamide, polyimide, and aramid. In addition, the said separator is 10-300.
The thickness is 0 μm, preferably 20 to 1500 μm. When a thickness in this range is used, a stable equivalent series resistance can be obtained.

The support plate may be any material as long as it can maintain the strength of the multilayer capacitor. In the present invention, aluminum is used to form the through holes. The size and shape of the support plate, and the shape of the through hole formed in the support plate,
The size and spacing may be any size as long as the support plate can maintain the strength of the multilayer capacitor, but since it is desirable that the liquid material easily penetrates into the inside of the laminate, the through hole of the support plate and It is preferable that the positions of the through-holes in the cathode foil and / or the anode foil are matched. Accordingly, it is preferable that the through holes of the support plate have substantially the same size, spacing and shape as the through holes of the cathode foil and / or the anode foil. However, as another embodiment of the support plate, a mesh-like support plate is used. Can also be used. Note that it is preferable to dispose the support plates on both sides of the capacitor element because the strength is improved.

The dimensions of the cathode electrode foil and the anode electrode foil may be such that 3,4-ethylenedioxythiophene and the oxidizing agent penetrate into the center of the lamination. Further, the size may be such that the anode foil can be sandwiched by the cathode foil, and it is optional depending on the specification of the solid electrolytic capacitor to be manufactured. The separator may have a width slightly larger than the cathode foil according to the dimensions of the cathode electrode foil and the anode electrode foil. In order to obtain a capacitor having the performance of the present invention, the vertical dimension of both electrode foils is usually 10 mm or more, preferably 20 mm or more, and typically 25 to 50 mm. Similarly, the lateral dimension of the anode electrode foil is usually 10 mm or more, preferably 20 m
m or more, and typically 25 to 50 mm. The lateral dimension of the cathode electrode foil, when sandwiching the anode electrode foil, may be at least twice the anode electrode foil, and is usually 20 mm or more,
It is preferably 50 mm or more, and typically 50 to 10 mm.
0 mm.

The capacitor element is formed by stacking a plurality of elements, usually 2 to 20, preferably 5 to 20 elements, each having a separator laminated on the cathode electrode foil and an anode electrode foil further laminated thereon and further laminated with a separator interposed therebetween. Stack up to 15 sheets. In addition, a separator is stacked on the cathode electrode foil, and a plurality of elements are similarly stacked so as to sandwich the anode electrode with the separator interposed therebetween. And it is preferable to form by arranging the support plate which has a through-hole on at least one side of this laminated body. With this configuration, the oxide film layers on both surfaces of the anode foil overlap with the cathode foil via the separator, so that the oxide film layers on both surfaces of the anode foil function as a dielectric. By the configuration of laminating so as to sandwich, it is possible to reduce the number of anode electrode foils required to obtain the same capacitance as compared to the case where the anode foil and the cathode foil are simply laminated via the separator,
It is possible to reduce the thickness and height.

By impregnating the capacitor element with 3,4-ethylenedioxythiophene and an oxidizing agent, the 3,4-ethylenedioxythiophene and the oxidizing agent penetrate into the inside of the capacitor element, and Process and mild chemical polymerization reaction that occurs appropriately after infiltration
A polymer of ethylenedioxythiophene, that is, a solid electrolyte layer is formed inside a capacitor element while being held by a separator.

3,4-ethylenedioxythiophene is
It can be obtained by a known production method disclosed in JP-A-2-15611 and the like. Further, the above-mentioned polymer of 3,4-ethylenedioxythiophene is poly3,4-ethylenedioxythiophene polymerized to an extent that it becomes a solid at normal temperature.

As the oxidizing agent, a solution obtained by dissolving ferric p-toluenesulfonate, which is an iron salt of aromatic sulfonic acid, in a butanol solvent is used. As the solvent in the oxidizing agent, a normal organic solvent such as alcohols such as ethanol and butanol can be used.

As a method of impregnating the capacitor element with 3,4-ethylenedioxythiophene and an oxidizing agent, not only a method of immersing the capacitor element in a liquid in which 3,4-ethylenedioxythiophene and the oxidizing agent are mixed in advance, but also a method of impregnating the capacitor element.
As another embodiment, a method of immersing a capacitor element immersed in 3,4-ethylenedioxythiophene in an oxidizing agent, and a method of immersing a capacitor element immersed in an oxidizing agent in 3,4-ethylenedioxythiophene, Moreover,
A method is also possible in which the immersion operation is replaced by ejection of a solution from a syringe.

The temperature condition during the polymerization is preferably from 20 to 180 ° C. When the polymerization temperature is 20 ° C. or lower, the formation of 3,4-ethylenedioxythiophene does not proceed well, and the capacitance decreases and the equivalent series resistance increases. At a temperature higher than 180 ° C., the decomposition of 3,4-ethylenedioxythiophene occurs, the capacitance decreases, and the equivalent series resistance increases. That is, excellent high-frequency characteristics cannot be obtained.

The pressure conditions during the polymerization are 30 to 1000 kg /
cm², Especially 100-600kg / cm ²Is preferred. 30
kg / cm²If the pressure is less than the produced polymer and electrode foil
Does not progress well, reducing capacitance and equivalent
The series resistance increases. 1000kg / cm²Than
Even at high pressure, the monomer and oxidizer between the electrode foils
As the amount decreases, the amount of polymer formed decreases, and
The series resistance increases. In other words, excellent high-frequency characteristics
I can't get it.

A solid electrolyte layer is obtained by advancing the polymerization reaction for 30 minutes or more under the above polymerization conditions. The reaction time of this polymerization reaction is preferably 30 minutes or more at which the polymerization reaction can be completely completed.

After the formation of the solid electrolyte layer by the polymerization reaction, in order to repair the oxide film, re-chemical formation is favorably promoted with moisture penetrating from the through holes formed in the cathode under conditions of high humidity at normal temperature or higher. The temperature condition is 4
0 ° C. or higher, particularly preferably 50 to 120 ° C., and more preferably 60 to 120 ° C.
90 ° C. is preferred. If the temperature is lower than 40 ° C., the rechemical conversion voltage does not increase, and the chemical conversion treatment cannot be performed. Humidity condition is 2
0-60% RH is preferred. If the humidity is less than 20% RH,
The water required for re-chemical formation is insufficient, and the voltage does not rise stably. If it exceeds 60% RH, moisture will be excessive, and the voltage will not rise stably. At this time, even if an anode foil formed at a high voltage is used, it can be re-formed at a high voltage,
High withstand voltage can be achieved.

After the re-chemical conversion treatment, a voltage is applied as a water removing step to prevent an increase in equivalent series resistance value and leakage current. As another embodiment of the water removal, it is possible to leave at high temperature and low humidity. By removing water, gas generation due to the deterioration of the electrode foil due to residual water, swelling of the capacitor and deterioration of high frequency characteristics are suppressed,
High temperature life characteristics are improved.

According to the above embodiment, high withstand voltage of 100 V or more, high capacitance of 50 μF or more, and 5 to 1
A large flat solid electrolytic capacitor having excellent high frequency characteristics with an equivalent series resistance of 100 mΩ or less at 000 KHz can be obtained.

[0043]

Next, a method of manufacturing a solid electrolytic capacitor according to the present invention and a solid electrolytic capacitor obtained by the method will be specifically described with reference to the drawings.

Example 1 FIG. 1 shows a solid electrolytic capacitor according to the present invention.
Is an aluminum foil having a length of 30 mm and a width of 40 mm. The surface of the anode electrode foil 1 was subjected to a chemical conversion treatment, an oxide film layer 4 made of aluminum oxide was formed on the surface, and through holes were formed at intervals of 3 mm and 10% in area ratio to the foil. The cathode electrode foil 2 has a vertical dimension of 30 mm,
An aluminum foil having a lateral dimension of 85 mm was subjected to the same chemical conversion treatment as that of the anode electrode foil 1, and then a titanium nitride film was formed by a cathodic arc plasma deposition method. Further, through holes were formed on the surface of the cathode foil at intervals of 3 mm at an area ratio of 10% to the foil. In order to repair the damaged portion or cut surface of the bipolar foil received in the processing step, the oxide film is formed again by performing repair formation in an aqueous solution of ammonium phosphate, and further boric acid for stabilizing the oxide film. It was immersed in an aqueous solution.

A thickness of 100 μm on the cathode electrode foil 2,
Glass separator 3 with a vertical dimension of 35 mm and a horizontal dimension of 90 mm
Were stacked so as to sandwich the anode electrode 1 with the separator 3 interposed therebetween (FIG. 2) to obtain a capacitor element 10.
Ten elements were further stacked via a separator, and a support plate 11 made of an aluminum plate having a vertical dimension of 35 mm and a horizontal dimension of 45 mm and having a through hole was disposed on at least one side of the laminate (FIG. 3). Note that lead wires 6 and 7 were electrically connected to the anode electrode foil 1 and the cathode electrode foil 2 of the capacitor element 10 in advance, respectively, and protruded from the end of the capacitor element 10.

The capacitor element 10 having the above configuration was impregnated with 3,4-ethylenedioxythiophene and an oxidizing agent. The oxidizing agent was p-
These mixed solutions were prepared using ferric toluenesulfonate.

The impregnation was performed by a method in which the capacitor element 10 was immersed in an impregnation tank storing a fixed amount of the mixed solution. Next, the capacitor element 10 impregnated with the mixed solution was pulled up from the impregnation tank, and was pressed under a pressure of 400 kg / cm ² for 1 hour.
Under heating at 50 ° C., a polymer by a polymerization reaction, that is, a solid electrolyte layer 5 was formed for 2 hours.

Further, re-chemical formation was performed by applying a voltage under the conditions of 85 ° C. and 40% RH. When applying voltage,
Since the water permeated through the through holes, the oxide film could be re-chemically treated in a state where the formation voltage was stably increased. Following this rechemical conversion treatment, a voltage was applied at 85 ° C.
After the step of removing moisture in the solid electrolyte, insert the solid electrolytic capacitor into a bag formed of a laminate sheet with the lead wires protruding out of the bag, and thermocompression-bond the opening by melting polypropylene. A series of manufacturing steps were completed through the steps of sealing and sealing.

Test Example Next, the solid electrolytic capacitor of Example 1 was manufactured as ten samples, and the electrical characteristics were measured, and the average value was determined. Table 1 shows the results. Note that the first embodiment shown in Table 1 has a rated voltage of 100 V and a rated capacitance of 5 V, respectively.
0 μF.

[0050]

[Table 1]

From these results, the solid electrolytic capacitor according to Example 1 had low values in terms of equivalent series resistance, tan δ, leakage current, etc., although the capacitance had a high value. That is, the capacitor had high capacity, excellent withstand voltage characteristics, and excellent high frequency characteristics.

[0052]

The polymerization of the 3,4-ethylenedioxythiophene monomer used in the present invention proceeds gently. Therefore, after the monomer and the oxidizing agent have sufficiently penetrated into the inside of the large-sized flat plate capacitor element, the polymerization reaction proceeds. The reaction is completed.
As a result, a dense and uniform solid electrolyte layer is satisfactorily formed, and the adhesion between the oxide film on the anode electrode foil and the solid electrolyte layer is increased, so that the capacitance increases and the equivalent series resistance value decreases. That is, a solid electrolytic capacitor having high capacitance and excellent high-frequency characteristics can be obtained. Further, in the withstand voltage characteristics, the characteristics of the polymer of 3,4-ethylenedioxythiophene itself are remarkably improved as compared with a conventional solid electrolytic capacitor using a conductive polymer for a solid electrolyte layer.

In the present invention, the polymer is formed under pressure during the polymerization reaction, so that the adhesion between the oxide film layer on the anode electrode foil and the solid electrolyte layer is significantly improved. In addition,
In the present invention, as a method for applying the pressure, a method is employed in which the pressure is sandwiched from both sides of the laminate. For this reason,
It has become possible to uniformly press the anode electrode foil and the cathode electrode foil via the separator. By using this method,
It has become possible to arbitrarily set the strength of the pressure to the most preferable condition. As a result, optimal pressurizing conditions can be created to promote the polymerization reaction, and the efficiency of increasing the adhesion between the oxide film layer on the anode electrode foil and the solid electrolyte layer is high.

In the present invention, since the through holes are formed in the support plate, the anode foil, and the cathode foil, the liquid material can sufficiently penetrate into the solid electrolytic capacitor through the through holes. Therefore, a sufficient amount of 3,4-ethylenedioxythiophene and the oxidizing agent can be uniformly penetrated into the inside of the stack of large flat plates, and a dense and uniform solid electrolyte layer can be formed. In addition, at the time of re-formation under high-humidity conditions at normal temperature or higher, re-formation at a high formation voltage, i.e., the formation of the anodic oxide film by the water that has passed through the through-hole and penetrated into the solid electrolyte layer sandwiched between the two electrode foils. Repair proceeds. The resulting solid electrolytic capacitor has excellent withstand voltage. Also,
By forming the through holes in the anode foil, the low frequency characteristics are also improved.

Further, by disposing a support plate on at least one side of the present capacitor, it is possible to maintain the strength of a large flat-plate multilayer capacitor.

Further, by adopting a method of laminating the elements having the structure of the present invention, it is possible to increase the capacitance and obtain a desired capacitance. In the solid electrolytic capacitor of the present invention, since the thicknesses of the electrode foil and the separator are thin, the solid electrolytic capacitor can be kept thin even if the above lamination is repeated.

The solid electrolytic capacitor of the present invention obtained by the above-described method has a high capacity requirement and a high withstand voltage requirement, a flattening requirement, that is, a demand for a thinner and lower profile, and an excellent requirement for the recent functionalization of circuits. In response to the demand for high-frequency characteristics, it has excellent high-frequency characteristics, but particularly excellent high withstand voltage and high capacitance, and is compactly stored in automotive applications. It became possible.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a capacitor element used in the present invention.

FIG. 2 is a perspective view showing a method of laminating capacitor elements used in the present invention.

FIG. 3 is a perspective view in which capacitor elements used in the present invention are further laminated.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode electrode foil 2 Cathode electrode foil 3 Separator 5 Solid electrolyte layer 6, 7 Lead wire 10 Capacitor element 11 Support plate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01G 9/05 H 9/24 C

Claims (5)

[Claims] 1. A capacitor element is obtained by laminating a cathode electrode foil having a through hole and an anode electrode foil having a dielectric oxide film formed on the surface thereof and having a through hole via a separator. After a support plate having a through hole is arranged on at least one side of the obtained laminate, the separator is impregnated with a 3,4-ethylenedioxythiophene monomer and an oxidizing agent, and heated under pressure. A large flat-plate laminated solid electrolytic capacitor formed by polymerizing the monomer and having high withstand voltage, high capacitance, and excellent high-frequency characteristics. 2. The pressure at the time of pressurization is 30 to 1000 kg / c.
The solid electrolytic capacitor according to claim 1, characterized in that the m ^2. 3. A high withstand voltage of 100 V or more, a high capacitance of 5 μF or more, and an excellent high frequency characteristic of an equivalent series resistance at 5 to 1000 KHz of 100 mΩ or less. The multilayer solid electrolytic capacitor as described in the above. 4. A capacitor element is obtained by laminating a cathode electrode foil having a through hole and an anode electrode foil having a dielectric oxide film formed on its surface and having a through hole via a separator. After placing a support plate having a through hole on at least one side of the obtained laminate, the separator is impregnated with a 3,4-ethylenedioxythiophene monomer and an oxidizing agent, and the laminate is pressed under pressure. The monomer is polymerized by heating in, and re-chemically formed under a high humidity condition of room temperature or higher,
The method for producing a multilayer solid electrolytic capacitor according to claim 1, wherein moisture is removed. 5. The pressure at the time of pressurization is 30 to 1000 kg / c.
The method for producing a solid electrolytic capacitor according to claim 4, characterized in that the m ^2.