JP2000114118A - Solid electrolytic capacitor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid electrolytic capacitor, which uses PEDT (polyethylene dioxithiophene) as the electrolyte and has the maximum working temperature of at least 105 deg.C and its manufacturing method. SOLUTION: An anode foil and a cathode foil on the surfaces, of which oxide covering film layers are formed, are wound via a separator, and a capacitor element 1 is formed. The capacitor element 1 is impregnated with EDT (ethylene dioxithiophene) monomer and further with butanol solution of ferric paratoluene sulfonic acid of 40-60% and heated at 20-180 deg.C for at least 30 minutes. A solid electrolyte layer composed of PEDT is formed. The capacitor element 1 is set to stand still in a thermostatic chamber at 15-120 deg.C for 5-30 minutes and then dried. After that, lead terminals of the capacitor element 1 are inserted in through-holes 5 formed in a sealing rubber 3, the capacitor element 1 is accommodated in a cylindrical close-end sheath case 2. Finally, an aperture part of the sheathing case 2 is sealed by caulking work, and a solid electrolytic capacitor is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolytic capacitor and a method of manufacturing the same, and more particularly, to a solid electrolytic capacitor improved to improve high-temperature life characteristics and a method of manufacturing the same.

[0002]

2. Description of the Related Art In an electrolytic capacitor using a metal having a valve action such as tantalum or aluminum, a valve action metal as an anode-side counter electrode is formed into a shape of a sintered body or an etching foil to expand a dielectric material. By using such a structure, it is possible to obtain a large capacity with a small size. In particular, a solid electrolytic capacitor using a solid electrolyte as an electrolyte has characteristics that it is small, large-capacity, low equivalent series resistance, easy to chip, and suitable for surface mounting. It is indispensable for miniaturization, high performance, and low cost of electronic devices.

In this type of solid electrolytic capacitor, for small size and large capacity applications, generally, an anode foil and a cathode foil made of valve metal such as aluminum are wound with a separator interposed therebetween to form a capacitor element. The capacitor element is impregnated with a driving electrolyte, and the capacitor element is housed in a metal case such as aluminum or a synthetic resin case, and has a sealed structure. Note that as the anode material, aluminum, tantalum, niobium, titanium, or the like is used, and as the cathode material, the same kind of metal as the anode material is used.

As a solid electrolyte used for a solid electrolytic capacitor, manganese dioxide, 7, 7, 8, 8-
A tetracyanoquinodimethane (TCNQ) complex is known, but recently, polyethylenedioxythiophene (hereinafter, referred to as PEDT), which has a slow reaction rate and excellent adhesion to an oxide film layer of an anode electrode, has been developed. There is a technique (Japanese Patent Laid-Open No. 2-15611) that has been focused on.

A solid electrolytic capacitor having such a solid electrolyte layer is manufactured by a manufacturing process of chemical formation, element formation, solid electrolyte layer formation, resin sealing, and aging. Hereinafter, as an example of such a solid electrolytic capacitor, a process of manufacturing a solid electrolytic capacitor of a type in which a solid electrolyte layer made of polyethylene dioxythiophene is formed on a wound capacitor element will be briefly described.

First, the surface of an anode foil made of a valve metal such as aluminum is roughened by electrochemical etching in an aqueous chloride solution to form a large number of etching pits. A voltage is applied in an aqueous solution to form an oxide film layer serving as a dielectric (chemical formation). Like the anode foil, the cathode foil is made of valve metal such as aluminum, but its surface is only subjected to etching. Further, lead wires for connecting the respective electrodes to the outside are connected to the anode foil and the cathode foil by known means such as stitching and ultrasonic welding.

Next, the anode foil and the cathode foil each having the oxide film layer formed on the surface as described above are wound through a separator to form a capacitor element (element formation). Then, the capacitor element is impregnated with ethylenedioxythiophene (hereinafter, referred to as EDT) and an oxidizing agent, heated,
A solid electrolyte layer made of polyethylene dioxythiophene (PEDT) is formed (solid electrolyte layer formation).

Thereafter, an epoxy resin-based thermosetting resin using an acid anhydride-based curing agent is adhered to the surface of the capacitor element and thermally cured, thereby covering the outer periphery of the capacitor element with an exterior resin. (Resin sealing) to complete a solid electrolytic capacitor. In addition, when resin sealing is performed in this way,
Since the oxide film layer formed on the surface of the anode foil is damaged and the leakage current characteristics decrease, the oxide film layer is repaired by applying a voltage according to the capacitor rated voltage and performing high-temperature aging after resin sealing. And improve the characteristics.

[0009]

However, a high-temperature life test was conducted on a solid electrolytic capacitor using PEDT as a solid electrolyte as described above and an epoxy resin using an acid anhydride-based curing agent as a sealing material. However, the characteristics deteriorated in a high-temperature life test exceeding 105 ° C., so the maximum operating temperature was limited to 105 ° C.

As described above, in a solid electrolytic capacitor using PEDT as a solid electrolyte and an epoxy resin using an acid anhydride-based curing agent as a sealing material, 105 ° C.
It is considered that the characteristics are degraded in the high-temperature life test exceeding the above for the following reasons. That is, the epoxy resin using an acid anhydride-based curing agent, which has been conventionally used as an exterior resin for covering the outer periphery of the capacitor element, has a property of absorbing moisture in the curing process, but is impregnated with this resin, before being cured. In the process, since a certain amount of moisture is adsorbed on the capacitor element, even if moisture in the capacitor element is absorbed by this resin during the curing process, moisture still remains in the capacitor element. Therefore, 105
At a temperature of not more than ° C., it is considered that the performance of the oxide film is favorably maintained by the residual moisture, and the initial characteristics such as the withstand voltage characteristic and the leakage current characteristic are favorably maintained. However, at a high temperature of 105 ° C. or more, moisture remaining in the capacitor element causes hydration deterioration of the oxide film and PE
It is considered that the characteristics are degraded because it acts to lower the conductivity of DT.

The present invention has been proposed to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a solid electrolytic capacitor using PEDT as an electrolyte and having a maximum operating temperature of 105 ° C. or more, and a solid electrolytic capacitor using the same. It is to provide a manufacturing method.

[0012]

Means for Solving the Problems To solve the above-mentioned problems, the present inventors have made intensive studies on a solid electrolytic capacitor capable of increasing the maximum operating temperature and a method for manufacturing the same, and as a result, the present invention has been made. Is completed. In other words, the present inventor believes that if a certain amount of moisture remaining in the capacitor element is removed in the life test at 130 ° C., the deterioration of the characteristics can be suppressed. Stored in
Various sealing means and sealing methods were examined.

That is, according to the first aspect of the present invention, there is provided a capacitor in which a bipolar electrode foil connected to an electrode lead-out means is wound via a separator, and a solid electrolyte layer made of polyethylenedioxythiophene is formed between the bipolar electrode foils. Element, a solid electrolytic capacitor having a bottomed cylindrical outer case for housing the capacitor element, and sealing means attached to the opening of the outer case, wherein the sealing means is made of sealing rubber, The electrode lead-out means is inserted into a through hole formed in the sealing rubber, and the opening of the outer case is crimped.

The invention described in claim 7 is the first invention.
From the viewpoint of the method described in the above, winding the bipolar electrode foil connected to the electrode lead means through a separator, forming a solid electrolyte layer made of polyethylene dioxythiophene between the bipolar electrode foil In the method for manufacturing a solid electrolytic capacitor in which a capacitor element is formed, the capacitor element is housed in a bottomed cylindrical outer case, and the opening of the outer case is sealed, the capacitor element is subjected to a drying treatment. Thereafter, the electrode lead-out means is inserted into a through-hole formed in the sealing rubber loaded in the opening of the outer case, and the capacitor element is housed in the outer case, and caulked to the opening of the outer case. It is characterized by processing.

According to the first or seventh aspect of the present invention, since the capacitor element on which the PEDT layer is formed as the electrolyte layer is dried before being stored in the outer case, the drying process is performed. Thereafter, water at the crystallization water level remains in the capacitor element, and the performance of the oxide film is kept good by the remaining water at the crystallization water level, so that the initial characteristics are kept good. On the other hand, even if this amount of water remains, the water does not deteriorate the hydration of the oxide film or lower the electrical conductivity of the PEDT, so that the characteristics are not deteriorated. It is.

Further, since the opening of the outer case is sealed with a sealing rubber and then the opening of the case is crimped, the electrode lead-out means comes into close contact with the through hole provided in the sealing rubber. As a result, the capacitor element in the outer case can be prevented from absorbing moisture, so that the high-temperature life characteristics do not deteriorate.

Further, after the electrode lead-out means is inserted into a through hole provided in the sealing rubber, the capacitor element is housed in a cylindrical outer case having a bottom, and the opening of the outer case is closed by caulking. Therefore, the electrode lead-out means comes into close contact with the through-hole provided in the sealing rubber and is firmly fixed. As a result, even if a lateral force is applied to the electrode lead-out means, no force is applied to the electrode foil and the electrode foil is not damaged.

According to a second aspect of the present invention, there is provided a capacitor element in which a bipolar electrode foil to which electrode extraction means is connected is wound through a separator, and a solid electrolyte layer made of polyethylenedioxythiophene is formed between the bipolar electrode foils. In a solid electrolytic capacitor including a bottomed cylindrical outer case for housing the capacitor element and sealing means attached to an opening of the outer case, the sealing means is at least one of an upper surface and a lower surface of a sealing rubber. The electrode lead-out means is inserted into a through-hole formed in this fluororesin-applied rubber, and a caulking process is applied to the opening of the outer case. It is characterized by having been done.

The invention described in claim 8 is the second invention.
From the viewpoint of the method described in the above, winding the bipolar electrode foil connected to the electrode lead means through a separator, forming a solid electrolyte layer made of polyethylene dioxythiophene between the bipolar electrode foil In the method for manufacturing a solid electrolytic capacitor in which a capacitor element is formed, the capacitor element is housed in a bottomed cylindrical outer case, and the opening of the outer case is sealed, the capacitor element is subjected to a drying treatment. Thereafter, the electrode lead-out means is inserted into a through-hole formed in a fluororesin-applied rubber in which a fluororesin is attached to at least one of an upper surface and a lower surface of a sealing rubber, and this capacitor element is inserted into the outer case. The housing is housed, and the opening of the outer case is subjected to caulking.

According to the second or eighth aspect of the present invention having the above configuration, the first or seventh aspect is provided.
The following effects can be obtained in addition to the functions and effects of the invention of (1). That is, since a fluorine resin having high hardness is attached to the sealing rubber, the electrode lead-out means is more firmly fixed by the fluorine resin portion. As a result, even if a lateral force is applied to the electrode lead-out means, the transmission of this force to the electrode foil is suppressed, so that damage to the oxide film is reduced.

According to a third aspect of the present invention, there is provided a capacitor element in which a bipolar electrode foil to which electrode extraction means is connected is wound through a separator, and a solid electrolyte layer made of polyethylene dioxythiophene is formed between the bipolar electrode foils. In a solid electrolytic capacitor including a bottomed cylindrical outer case for storing the capacitor element and sealing means attached to an opening of the outer case, the sealing means is provided with a concave portion on an upper surface thereof. It is made of a sealing rubber in which an epoxy resin layer is formed in a concave portion, and the electrode lead-out means is inserted into a through hole formed in the sealing rubber, and the opening of the outer case is crimped. It is characterized by the following.

The invention according to claim 9 is the third invention.
From the viewpoint of the method described in the above, winding the bipolar electrode foil connected to the electrode lead means through a separator, forming a solid electrolyte layer made of polyethylene dioxythiophene between the bipolar electrode foil In the method for manufacturing a solid electrolytic capacitor in which a capacitor element is formed, the capacitor element is housed in a bottomed cylindrical outer case, and the opening of the outer case is sealed, the capacitor element is subjected to a drying treatment. Thereafter, the electrode lead-out means is inserted into a through-hole formed in a sealing rubber provided with a concave portion on the upper surface, and the capacitor element is housed in the outer case,
After caulking the opening of the outer case, the recess is filled with an epoxy resin and heated to cure the epoxy resin.

According to the third or ninth aspect of the present invention having the above configuration, the first or the seventh aspect of the present invention.
The following effects can be obtained in addition to the functions and effects of the invention of (1). That is, since the epoxy resin layer formed in the concave portion of the sealing rubber is harder than the sealing rubber, the electrode drawing means is more firmly fixed by the epoxy resin layer portion. As a result, even if a lateral force is applied to the electrode lead-out means, this force is suppressed from being transmitted to the electrode foil,
The oxide film is less damaged.

According to a fourth aspect of the present invention, there is provided a capacitor element in which a bipolar electrode foil to which an electrode lead-out means is connected is wound through a separator, and a solid electrolyte layer made of polyethylenedioxythiophene is formed between the bipolar electrode foils. In a solid electrolytic capacitor provided with a bottomed cylindrical outer case for housing the capacitor element and sealing means attached to an opening of the outer case, the sealing means is made of a semi-cured epoxy resin plate. A crimping process is performed on an opening of the outer case.

Further, the invention described in claim 10 is an invention in which the invention described in claim 4 is grasped from the viewpoint of a method.
The bipolar electrode foil to which the electrode lead-out means is connected is wound through a separator, a solid electrolyte layer made of polyethylene dioxythiophene is formed between the bipolar electrode foils to form a capacitor element, and the capacitor element is formed into a bottomed cylindrical shape. In a method for manufacturing a solid electrolytic capacitor that is housed in an outer case and seals an opening of the outer case, after performing a drying process on the capacitor element,
Inserted into the through-hole formed in the semi-cured epoxy resin plate, house this capacitor element in the outer case,
The opening of the outer case is crimped, and then heated to cure the semi-cured epoxy resin plate.

According to the fourth or tenth aspect of the present invention having the above configuration, the following effects can be obtained in addition to the functions and effects of the first or seventh aspect. In other words, since a semi-cured epoxy resin plate is used as the sealing material, the sealing process is facilitated, and after curing, the same effect as sealing with a hard epoxy resin is obtained. By layer part,
The electrode lead means is more firmly fixed. as a result,
Even if a lateral force is applied to the electrode lead-out means, the transmission of this force to the electrode foil is suppressed, so that damage to the oxide film is reduced.

According to a fifth aspect of the present invention, there is provided a capacitor element in which a bipolar electrode foil connected to an electrode lead-out means is wound through a separator, and a solid electrolyte layer made of polyethylenedioxythiophene is formed between the bipolar electrode foils. In a solid electrolytic capacitor provided with a bottomed cylindrical outer case for accommodating the capacitor element and sealing means mounted on the opening of the outer case, the sealing means is formed with a sealing rubber and a sealing rubber. It is composed of an epoxy resin layer, and is characterized in that an opening of the outer case is laterally crimped.

The invention described in claim 11 is an invention in which the invention described in claim 5 is grasped from the viewpoint of a method.
The bipolar electrode foil to which the electrode lead-out means is connected is wound through a separator, a solid electrolyte layer made of polyethylene dioxythiophene is formed between the bipolar electrode foils to form a capacitor element, and the capacitor element is formed into a bottomed cylindrical shape. In a method for manufacturing a solid electrolytic capacitor that is housed in an outer case and seals an opening of the outer case, after performing a drying process on the capacitor element,
Insert this through the through hole formed in the sealing rubber, house this capacitor element in the outer case, after closing the opening of the outer case with the sealing rubber, perform a lateral caulking process, and the upper surface of the sealing rubber A space surrounded by the side surface of the outer case is filled with an epoxy resin, and the epoxy resin is heated to cure the epoxy resin.

According to the fifth or eleventh aspect of the present invention having the above-described structure, the following effects can be obtained in addition to the functions and effects of the first and seventh aspects. That is, since the epoxy resin layer formed on the upper surface of the sealing rubber is harder than the sealing rubber, the lead wire is more firmly fixed by the epoxy resin layer portion. As a result, even if a lateral force is applied to the electrode lead-out means, the transmission of this force to the electrode foil is suppressed, so that damage to the oxide film is reduced.

According to a sixth aspect of the present invention, in the solid electrolytic capacitor according to any one of the first to fifth aspects, the sealing rubber is ethylene propylene rubber (EP).
M), ethylene propylene diene terpolymer (EPD)
M), isobutylene isopropylene rubber (IIR), styrene butadiene rubber, nitrile propylene rubber.

That is, the material of the sealing rubber can be appropriately selected. Particularly, the use of the material described in claim 6 provides a better effect.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a solid electrolytic capacitor according to the present invention and a method for manufacturing the same (hereinafter, referred to as embodiments) will be specifically described with reference to the drawings.

[1. First Embodiment] [1-1. Configuration] FIG. 1 is a sectional view showing a configuration of a first embodiment of a solid electrolytic capacitor according to the present invention. That is, as shown in FIG. 1, a capacitor element 1 in which a bipolar electrode foil to which a lead wire 4 serving as an electrode lead-out means is connected via a separator is provided in a bottomed cylindrical outer case 2 made of aluminum or the like. It is stored in. Further, the lead wire 4 is inserted into a through hole 5 provided in a sealing rubber 3 which is a sealing member attached to an opening of the outer case 2,
It has been pulled out. The opening of the outer case 2 is sealed by the sealing rubber 3, and the upper end of the outer case is crimped.

[1-2. Manufacturing Method] Next, the method for manufacturing the solid electrolytic capacitor according to the present embodiment will be explained. That is, an anode foil and a cathode foil each having an oxide film layer formed on the surface are wound through a separator to form a capacitor element. Then, the capacitor element was impregnated with an EDT monomer, and further impregnated with a 40 to 60% ferric paratoluenesulfonate butanol solution to obtain 20 to 1%.
Heat at 80 ° C. for 30 minutes or more to produce a solid electrolyte layer made of PEDT. Then, this capacitor element is
Leave to dry in a thermostat at ~ 120 ° C for 5-30 minutes. After that, insert the lead terminal of this capacitor element into the through hole provided in the sealing rubber, then store the capacitor element in a bottomed cylindrical outer case, and finally seal the opening of the outer case by caulking. To form a solid electrolytic capacitor.

Examples of the sealing rubber include ethylene propylene rubber (EPM), ethylene propylene diene terpolymer (EPDM), isobutylene isopropylene rubber (IIR), and styrene butadiene which are conventionally used as sealing rubber for electrolytic capacitors. Rubber, nitrile propylene rubber and the like can be used. Among them, EPM, EPDM, IIR by peroxide crosslinking and IIR by resin crosslinking are preferable, and IIR by resin crosslinking having high hardness is particularly preferable. The sealing rubber is obtained by kneading the above-mentioned polymer, a crosslinking agent and a filler such as alumina, silica, carbon or the like, and molding this into a predetermined shape by a molding press or the like.

Further, in the caulking process, a lead wire of the capacitor element is inserted into a through hole provided in the sealing rubber,
The sealing rubber and the capacitor element are housed in a bottomed cylindrical outer case having an opening, and the opening of the case loaded with the sealing rubber is pressed laterally by a method such as pressing a rotating disk-shaped jig. And drawing from above.

As a method for drying the capacitor element, a method of leaving the capacitor element in a constant temperature bath, a method of blowing hot air on the capacitor element, a method of leaving the capacitor element in a decompression tank, and the like, may be used. Various methods can be applied as long as the method can remove. The drying temperature is 15 to 120 ° C, and the drying time is 5 to
30 minutes is desirable.

[1-3. Operation and Effect] The operation and effect of the present embodiment as described above are as follows. That is, in the present embodiment, since the capacitor element on which the PEDT layer is formed as the electrolyte layer is dried before being housed in the outer case, moisture of the crystallization water level remains in the capacitor element after this drying treatment. ing. Since the performance of the oxide film is favorably maintained by the remaining water of the crystallization water level, the initial properties such as the withstand voltage property and the leakage current property are favorably maintained. On the other hand, with respect to the high-temperature life characteristics, even if this amount of water remains, the water does not act on the hydration deterioration of the oxide film and the characteristics are not degraded, so that the high-temperature life characteristics are also kept good. It is.

If the sealing properties of the capacitor element after being stored in the outer case are poor, the capacitor element absorbs moisture,
At a high temperature of 105 ° C. or higher, it is considered that the moisture remaining in the capacitor element acts on hydration deterioration of the oxide film and the like, so that the characteristics are degraded. In the present embodiment, the opening of the outer case is sealed with a sealing rubber. Then, since the opening of the case is crimped, the lead wire comes into close contact with the through hole provided in the sealing rubber. As a result, the capacitor element in the outer case can be prevented from absorbing moisture, so that the high-temperature life characteristics do not deteriorate.

In general, in a solid electrolytic capacitor, when a lateral force is applied to a lead wire, a force is applied to the electrode foil through a connection portion between the lead wire and the electrode foil, and the electrode foil is damaged. Therefore, it is preferable that the lead wire is firmly fixed.However, according to the solid electrolytic capacitor of the present embodiment, after inserting the lead wire into the through hole provided in the sealing rubber, the capacitor element is formed into a bottomed cylindrical shape. Since the lead wire is housed in the outer case and the opening of the outer case is sealed by caulking, the lead wire is in close contact with the through hole provided in the sealing rubber and is firmly fixed.

Further, in the present embodiment, the outer case is sealed with the sealing rubber, and the tip of the opening of the outer case is brought into contact with the sealing rubber by caulking, so that the pressing of the sealing rubber can be suppressed. Since the sealing rubber is strong, it can be prevented that the sealing rubber jumps out of the outer case due to thermal stress.

[2. Second Embodiment] This embodiment is a modification of the sealing structure of the outer case in the first embodiment. Specifically, instead of the sealing rubber of the first embodiment,
It is a fluororesin-applied rubber in which a fluororesin such as Teflon (trade name) is adhered to a sealing rubber. Hereinafter, portions different from the first embodiment will be described.

[2-1. Configuration] FIG. 2 is a sectional view showing the configuration of a second embodiment of the solid electrolytic capacitor according to the present invention. That is, as shown in FIG. 2, in the present embodiment, a fluororesin 10 such as Teflon is adhered to the entire lower surface of the sealing rubber 13, and the opening of the outer case 2 is sealed by the fluororesin applied rubber. I have.

The portion to which the fluororesin is applied may be on the upper surface of the sealing rubber 13 or on both upper and lower surfaces. Further, as the sealing rubber 13, the same material as shown in the first embodiment can be used. In addition, the thickness of the fluororesin applied to the sealing rubber 13 can be set as appropriate, but is determined by the relationship between the thickness of the fluororesin applied rubber and the swaged portion. That is, since the fluororesin has high hardness, it is not possible to perform crimping on the fluororesin portion. Therefore, the portion to be crimped must be sealing rubber, but the other portions can be made of fluororesin. Therefore, if the thickness of the fluororesin-applied rubber is large, the thickness of the fluororesin can be increased, and if the thickness is small, the thickness of the fluororesin must be reduced.

As the fluororesin to be attached to the sealing rubber, polytetrafluoroethylene (PTFE: Teflon), tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FE
P), tetrafluoroethylene-ethylene copolymer (E
TFE), polyfluorotrifluoroethylene (PCTF
E), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), chlorotrifluoroethylene-ethylene copolymer (ECTFE), polychlorotrifluoroethylene (PCTTE), or the like can be used. Among them, PTFE (Teflon), PFA, FEP, ETF
E is preferred, and PTFE (Teflon) is more preferred.

The method for attaching the fluororesin to the sealing rubber is as follows. That is, the surface of the fluororesin is roughened by ultraviolet irradiation, a solvent, or the like, this surface is brought into contact with the rubber before crosslinking, and then the rubber is crosslinked, thereby joining the fluororesin and the rubber.

[2-2. Operation / Effect] In the present embodiment as described above, the same operation / effect as in the first embodiment can be obtained. The functions and effects unique to the present embodiment are as follows. That is, in the present embodiment, since a fluorine resin such as Teflon having high hardness is attached to the sealing rubber 13, the lead wire is more firmly fixed by the fluorine resin portion. As a result, even if a force is applied to the lead wire from the side, the transmission of the force to the electrode foil is suppressed, so that damage to the oxide film is reduced.

[3. Third Embodiment] This embodiment is a modification of the sealing structure of the outer case in the first embodiment. Specifically, a recess is provided in the sealing rubber of the first embodiment, and an epoxy resin layer is provided in the recess. Is formed.
Hereinafter, portions different from the first embodiment will be described.

[3-1. Configuration] FIG. 3 is a sectional view showing the configuration of a third embodiment of the solid electrolytic capacitor according to the present invention. That is, as shown in FIG. 3, in the present embodiment, the recess 20 is formed in the space including the through hole 5 on the upper surface of the sealing rubber 23, and the epoxy resin layer 2 is formed in the recess 20.
1 is formed. Note that the position of the concave portion 20 formed in the sealing rubber 23 is not limited to that shown in FIG. 3 and may be any portion as long as the epoxy resin layer 21 formed in the concave portion can fix the lead wire 4.

[3-2. Manufacturing method] Hereinafter, the concave portion 20 will be described.
Next, the step of forming the epoxy resin layer 21 will be described. That is, in the manufacturing process of the solid electrolytic capacitor shown in the first embodiment, after the capacitor element 1 is housed in the outer case 2 and the sealing rubber 23 is crimped, the epoxy resin is filled in the recess 20, and then 20 to 200
The composition is cured by heating at 30C for 30 minutes to 48 hours.

[3-3. Operation / Effect] In the present embodiment as described above, the same operation / effect as in the first embodiment can be obtained. The functions and effects unique to the present embodiment are as follows. That is, in this embodiment, since the epoxy resin layer 21 formed in the concave portion 20 of the sealing rubber 23 is harder than the sealing rubber 23, the lead wire is more firmly fixed by this epoxy resin layer portion. As a result, even if a force is applied to the lead wire from the side, the transmission of the force to the electrode foil is suppressed, so that damage to the oxide film is reduced.

[4. Fourth Embodiment] This embodiment is a modified example of the sealing structure of the outer case in the first embodiment. Specifically, a semi-cured epoxy resin plate is used as a sealing member, and after caulking, It was cured by heating. Hereinafter, portions different from the first embodiment will be described.

[4-1. Configuration] FIG. 4 is a sectional view showing the configuration of a fourth embodiment of the solid electrolytic capacitor according to the present invention. That is, as shown in FIG. 4, in the present embodiment, a semi-cured epoxy resin plate 30 is used as a sealing member, and the opening of the outer case is sealed and swaged in the same manner as the sealing rubber of the first embodiment. After processing, it is cured by heating.

The semi-cured epoxy resin plate is a liquid epoxy resin that is filled into a mold or the like so as to have a plate shape.
It is formed into a rubber plate without being completely cured, and then cut into the same shape as the sealing rubber of the first embodiment, and can be used as a sealing material in the same manner as the sealing rubber. The semi-cured state must be in a rubber-like state and can be used as a sealing material by caulking. The curing method is the third
As in the embodiment, the composition is cured by heating at 20 to 200 ° C. for 30 minutes to 48 hours.

[4-2. Operation / Effect] In the present embodiment as described above, the same operation / effect as in the first embodiment can be obtained. The functions and effects unique to the present embodiment are as follows. That is, in the present embodiment, since a semi-cured epoxy resin plate is used as the sealing material, the sealing process is facilitated, and after curing, the same effect as that obtained by sealing with a hard epoxy resin is obtained. Therefore, the lead wire is more firmly fixed by the epoxy resin layer portion. As a result, even if a force is applied to the lead wire from the side, the transmission of the force to the electrode foil is suppressed, so that damage to the oxide film is reduced.

[5. Fifth Embodiment] This embodiment is a modified example of the sealing structure of the outer case in the first embodiment. Specifically, only lateral crimping is performed as a crimping process, and an epoxy resin layer is formed on the sealing rubber. Is formed. Hereinafter, portions different from the first embodiment will be described.

[5-1. Configuration] FIG. 5 is a sectional view showing the configuration of a fifth embodiment of the solid electrolytic capacitor according to the present invention. That is, as shown in FIG. 5, in the present embodiment, the opening of the outer case 2 is sealed with the sealing rubber 43 in the same manner as in the first embodiment, and then only lateral crimping is performed as a crimping process. A space surrounded by the side surface of the case is formed on the case, and the space is filled with epoxy resin, and the epoxy resin layer 40 is formed by heating and curing.

The lateral crimping is a process in which an opening of a case in which a sealing rubber is loaded is drawn from the side by a method such as pressing a rotating disk-shaped jig. Further, the epoxy resin may be 20 to 2 as in the third embodiment.
The composition is cured by heating at 00C for 30 minutes to 48 hours.

[5-2. Operation / Effect] In the present embodiment as described above, the same operation / effect as in the first embodiment can be obtained. The functions and effects unique to the present embodiment are as follows. That is, in the present embodiment, since the epoxy resin layer 40 formed on the upper surface of the sealing rubber 43 is harder than the sealing rubber 43, the lead wire is more firmly fixed by the epoxy resin layer portion. As a result, even if a force is applied to the lead wire from the side, the transmission of the force to the electrode foil is suppressed, so that damage to the oxide film is reduced.

[0060]

Hereinafter, the present invention will be described in more detail with reference to examples.

The solid electrolytic capacitor according to the present invention was produced as in the following examples. Further, as a conventional example, a solid electrolytic capacitor resin-sealed with an epoxy resin using an acid anhydride-based curing agent according to the above-described conventional technology was used. The test conditions were a charge / discharge test at 29 V and 1000 cycles, followed by a high-temperature load test at 130 ° C. for 500 hours.

(Example) A capacitor element is formed by winding an anode foil and a cathode foil each having an oxide film layer formed on a surface thereof through a separator. Then, this capacitor element is impregnated with an EDT monomer, and is further added as an oxidizing agent solution.
% Of ferric paratoluenesulfonate in butanol and heated at 100 ° C. for 1 hour to form a solid electrolyte layer made of PEDT. This capacitor element is
After being left to dry in a thermostat at 0 ° C. for 20 minutes, the electrode lead-out means of this capacitor element was changed to II by resin crosslinking.
R into the through-hole provided in the sealing rubber made of R
The capacitor element was housed in a bottomed cylindrical outer case, and finally the opening of the outer case was sealed by caulking to form a solid electrolytic capacitor. The solid electrolytic capacitor has a rated voltage of 25 WV and a rated capacity of 15 μF.

(Conventional Example) A solid electrolytic capacitor was formed in accordance with the above-mentioned conventional technique, using an epoxy resin using an acid anhydride-based curing agent as the exterior resin of the capacitor element.

[Comparative Results] With respect to the solid electrolytic capacitors of the example and the conventional example obtained by the above method, 29 V
After 1000 cycles of charge / discharge tests, 130 ° C., 50
When a 0-hour high-temperature load test was performed, the results shown in the following Table 1 were obtained.

[0065]

[Table 1]

As is clear from Table 1, at 130 ° C., 50
When a 0-hour high-temperature load test is performed, in the conventional example, Cap is reduced by 16% as compared with the initial value, and tan is reduced.
δ increased to about 2.2 times the initial value. In addition, the equivalent series resistance (ESR) increased to three times the initial value. On the other hand, in the embodiment, the initial characteristics are Cap, ta.
Both nδ and ESR were almost equal to the conventional example. Also, 1
When a high-temperature load test was performed at 30 ° C. for 500 hours,
Cap was reduced by 9.7% compared to the initial value, and tan δ was increased only about 1.2 times the initial value. Also,
The ESR increased only about 1.7 times the initial value.

As described above, in the conventional example in which the capacitor element was sealed with the epoxy resin using the acid anhydride curing agent, the ESR after the high temperature life test became three times the initial value for the following reason. It is thought that. That is, an epoxy resin using an acid anhydride-based curing agent conventionally used as an exterior resin for covering the outer periphery of the capacitor element,
Although it has the property of absorbing moisture during the curing process, a certain amount of moisture is adsorbed to the capacitor element in the process before impregnating and curing this resin. Even if absorbed, moisture still remains in the capacitor element. for that reason,
At a temperature of 105 ° C. or lower, it is considered that the performance of the oxide film is favorably maintained by the residual moisture, and the initial characteristics such as the withstand voltage characteristic and the leakage current characteristic are favorably maintained. However, at a high temperature of 105 ° C. or higher, it is considered that the characteristics have deteriorated because moisture remaining in the capacitor element acts on hydration deterioration of the oxide film and the like.

On the other hand, in the embodiment using the packaging means according to the present invention, it is considered that the characteristics can be maintained even in the high temperature life test at 130 ° C. for the following reasons. That is, in the present embodiment, P is used as the electrolyte layer.
The capacitor element on which the EDT layer is formed is dried before sealing with a resin. Even after this drying process, water at the level of crystallization water remains in the capacitor element. Therefore, it is considered that the performance of the oxide film is favorably maintained by the remaining water of the crystallization water level, and the initial characteristics such as the withstand voltage characteristic and the leakage current characteristic are favorably maintained. On the other hand, in the high-temperature life test at 130 ° C., even if such moisture remains, the characteristics do not deteriorate due to the hydration deterioration of the oxide film and the like. Conceivable.

If the sealing properties of the capacitor element after being stored in the outer case are poor, the capacitor element absorbs moisture,
As in the conventional example, at a high temperature of 105 ° C. or more, it is considered that the moisture remaining in the capacitor element acts on the hydration deterioration of the oxide film and the like, so that the characteristics are degraded. Good results were also obtained in the life test. This indicates that excellent sealing characteristics can be obtained by employing the configuration of the present invention.

As described above, in this embodiment, the same initial characteristics as those of the conventional example can be obtained. Even when a high-temperature load test is performed at 130 ° C. for 500 hours, the ESR is twice the initial value. , And the capacitance was within -10%, indicating stable characteristics, and it was found that the high-temperature life characteristics were improved by the present invention. In addition, since the high-temperature life characteristics at 130 ° C. are good, it can be said that the sealing performance by the sealing means of the present invention is also good.

[0071]

As described above, according to the present invention,
By adopting the configuration of each of the above embodiments, the PED
A solid electrolytic capacitor having T as an electrolyte and having a maximum use temperature of 105 ° C. or more and a method for producing the same can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a solid electrolytic capacitor according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a configuration of a second embodiment of the solid electrolytic capacitor according to the present invention.

FIG. 3 is a sectional view showing a configuration of a third embodiment of the solid electrolytic capacitor according to the present invention.

FIG. 4 is a sectional view showing a configuration of a solid electrolytic capacitor according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view showing a configuration of a fifth embodiment of the solid electrolytic capacitor according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Capacitor element 2 ... Outer case 3,13,23,43 ... Sealing rubber 4 ... Lead terminal 5 ... Through hole 10 ... Fluorine resin 20 ... Recess 21 ... Epoxy resin 30 ... Semi-cured epoxy resin 40 ... Epoxy resin layer

Claims (11)

[Claims] 1. A capacitor element in which a bipolar electrode foil to which an electrode lead-out means is connected is wound via a separator to form a solid electrolyte layer made of polyethylene dioxythiophene between the bipolar electrode foils, and the capacitor element is housed. In a solid electrolytic capacitor provided with a bottomed cylindrical outer case and sealing means attached to an opening of the outer case, the sealing means is made of sealing rubber, and a through hole formed in the sealing rubber is provided. A solid electrolytic capacitor, wherein the electrode lead-out means is inserted into the outer case, and an opening of the outer case is crimped. 2. A capacitor element in which a bipolar electrode foil to which an electrode lead-out means is connected is wound via a separator to form a solid electrolyte layer made of polyethylene dioxythiophene between the bipolar electrode foils, and the capacitor element is housed. In a solid electrolytic capacitor provided with a bottomed cylindrical outer case and sealing means attached to an opening of the outer case, the sealing means attaches a fluororesin to at least one of an upper surface or a lower surface of a sealing rubber. The electrode lead-out means is inserted into a through-hole formed in the fluororesin-applied rubber attached to the fluororesin-applied rubber, and a crimping process is performed on an opening of the outer case. Solid electrolytic capacitor. 3. A capacitor element in which a bipolar electrode foil to which an electrode lead-out means is connected is wound via a separator, and a solid electrolyte layer made of polyethylene dioxythiophene is formed between the bipolar electrode foils, and the capacitor element is housed. In a solid electrolytic capacitor provided with a bottomed cylindrical outer case and sealing means attached to an opening of the outer case, the sealing means is provided with a concave portion on an upper surface thereof, and an epoxy resin layer is formed in the concave portion. Made of sealed rubber,
A solid electrolytic capacitor, characterized in that the electrode lead-out means is inserted into a through hole formed in the sealing rubber, and the opening of the outer case is crimped. 4. A capacitor element in which a bipolar electrode foil to which an electrode lead-out means is connected is wound via a separator to form a solid electrolyte layer made of polyethylene dioxythiophene between the bipolar electrode foils, and the capacitor element is housed. In a solid electrolytic capacitor provided with a bottomed cylindrical outer case and sealing means attached to an opening of the outer case, the sealing means is made of a semi-cured epoxy resin plate, and the opening of the outer case is provided. A solid electrolytic capacitor characterized by being crimped. 5. A capacitor element in which a bipolar electrode foil connected to an electrode lead-out means is wound via a separator, and a solid electrolyte layer made of polyethylene dioxythiophene is formed between the bipolar electrode foils, and the capacitor element is housed. In a solid electrolytic capacitor provided with a bottomed cylindrical outer case and a sealing means attached to an opening of the outer case, the sealing means includes a sealing rubber and an epoxy resin layer formed thereon, A solid electrolytic capacitor, wherein an opening of the outer case is subjected to a horizontal crimping process. 6. The sealing rubber is made of ethylene propylene rubber (EPM), ethylene propylene diene terpolymer (EPDM), isobutylene isopropylene rubber (II).
The solid electrolytic capacitor according to any one of claims 1 to 5, wherein the solid electrolytic capacitor is a material selected from the group consisting of R), styrene butadiene rubber, and nitrile propylene rubber. 7. A capacitor element is formed by winding a bipolar electrode foil connected to an electrode lead-out means via a separator, forming a solid electrolyte layer made of polyethylene dioxythiophene between the bipolar electrode foils, and forming a capacitor element. Is stored in a bottomed cylindrical outer case, and in a method for manufacturing a solid electrolytic capacitor for closing an opening of the outer case, after performing a drying process on the capacitor element, the electrode lead-out means of the outer case is A solid electrolytic capacitor characterized by being inserted into a through hole formed in a sealing rubber loaded in an opening, storing the capacitor element in the outer case, and crimping the opening of the outer case. Manufacturing method. 8. A capacitor element formed by winding a bipolar electrode foil connected to an electrode lead-out means through a separator, forming a solid electrolyte layer made of polyethylene dioxythiophene between the bipolar electrode foils, and forming a capacitor element. Is stored in a cylindrical outer case with a bottom, and in a method for manufacturing a solid electrolytic capacitor for closing an opening of the outer case, after the capacitor element is subjected to a drying treatment, the electrode lead-out means is replaced with a sealing rubber. It is inserted into a through hole formed in a fluororesin-applied rubber in which a fluororesin is adhered to at least one of the upper surface and the lower surface, and this capacitor element is housed in the outer case, and caulked to an opening of the outer case. A method for producing a solid electrolytic capacitor, characterized by processing. 9. A capacitor element is formed by winding a bipolar electrode foil to which electrode extraction means is connected via a separator, forming a solid electrolyte layer made of polyethylene dioxythiophene between the bipolar electrode foils, and forming a capacitor element. In a method for manufacturing a solid electrolytic capacitor in which is enclosed in a bottomed cylindrical outer case and seals an opening of the outer case, after the capacitor element is subjected to a drying treatment, the electrode lead-out means is recessed on the upper surface. Is inserted into a through hole formed in the sealing rubber provided with, the capacitor element is housed in the outer case, and the opening of the outer case is crimped, and then the recess is filled with epoxy resin. Heat it up
A method for manufacturing a solid electrolytic capacitor, comprising curing the epoxy resin. 10. A capacitor element formed by winding a bipolar electrode foil connected to an electrode lead-out means through a separator, forming a solid electrolyte layer made of polyethylene dioxythiophene between the bipolar electrode foils, and forming a capacitor element. Is stored in a bottomed cylindrical outer case, and in a method for manufacturing a solid electrolytic capacitor for closing an opening of the outer case, after the capacitor element is subjected to a drying treatment, the electrode lead-out means is semi-cured. The capacitor element is inserted into a through-hole formed in the epoxy resin plate, the capacitor element is housed in the outer case, the opening of the outer case is crimped, heated, and the semi-cured epoxy resin plate is heated. A method for producing a solid electrolytic capacitor, characterized by curing 11. A capacitor element formed by winding a bipolar electrode foil connected to an electrode lead-out means via a separator, forming a solid electrolyte layer made of polyethylene dioxythiophene between the bipolar electrode foils, and forming a capacitor element. Is stored in a bottomed cylindrical outer case, and in a method for manufacturing a solid electrolytic capacitor for closing an opening of the outer case, after the capacitor element is subjected to a drying treatment, the electrode lead-out means is sealed with a sealing rubber. Inserted into the formed through-hole, house this capacitor element in the outer case,
After closing the opening of the outer case with a sealing rubber, a horizontal caulking process is performed, an epoxy resin is filled in a space surrounded by the upper surface of the sealing rubber and the side surface of the outer case, and the epoxy resin is heated to heat. A method for producing a solid electrolytic capacitor, characterized by curing.