JP6726835B2 - Electrolytic capacitor - Google Patents

Description

The present invention relates to a power storage device used in various electronic devices, industrial equipment, automobile equipment, and the like.

In a conventional electrolytic capacitor, an anode foil obtained by forming a chemical conversion film on an etching foil of a valve action metal such as aluminum and a cathode foil made of an etching foil of a valve action metal such as aluminum are wound with a separator made of insulating paper or the like interposed therebetween. The capacitor element was turned to form a capacitor element, and the capacitor element was impregnated with a driving electrolytic solution, and the capacitor element was housed in a cylindrical outer case with a bottom, and the opening of the outer case was sealed with a sealing material made of rubber. It is composed.

Further, recently, in order to reduce ESR in a high frequency region, a solid electrolytic capacitor using a solid electrolyte such as a conductive polymer having a higher electric conductivity than a conventional electrolytic solution as an electrolyte has been studied and commercialized. Such a solid electrolytic capacitor has a structure in which a conductive polymer is filled in the inside of a capacitor element wound with a separator between an anode foil and a cathode foil. (For example, patent document 1).

JP-A-63-158829

By the way, in recent years, electrolytic capacitors have tended to be used for in-vehicle applications, and have come to be mounted in control circuits and drive circuits of automobile engines and electric components. In such in-vehicle applications, the capacitor is constantly subjected to violent vibration due to the vibration of the vehicle while driving, the vibration of the engine, etc., and when it is installed in the engine room, etc., it is continuously exposed to large temperature changes. By such vibration and temperature change, the capacitor element housed inside the electrolytic capacitor vibrates or repeatedly contracts, thereby forming an anode foil and a cathode foil, or an anode foil and a separator, which constitute the capacitor element. Alternatively, the cathode foil and the separator may be displaced from each other, resulting in problems such as an increase in leakage current and a short circuit. Therefore, there is a need for an electrolytic capacitor that can withstand such severe vibration and large temperature changes.

Therefore, it is an object of the present invention to solve the above problems and provide an electrolytic capacitor having excellent vibration resistance and temperature change.

In order to achieve the above object, the electrolytic capacitor of the present invention is a capacitor element and an electrolyte having a winding element in which an anode foil provided with a dielectric layer on the surface and a cathode foil are wound with a separator interposed therebetween. An insulating resin layer is provided on at least a part of the end portion in the width direction of the anode foil, or at least a part of the end portion in the longitudinal direction, and the insulating resin layer is interposed between the cathode and the cathode. It is configured to overlap at least a part of the foil.

According to the electrolytic capacitor of the present invention, even in a use environment in which severe vibration and repeated large temperature changes are repeated, the anode foil and the cathode foil, or the anode foil and the separator, or the cathode foil and the separator, which form the capacitor element, Can be suppressed, and as a result, an electrolytic capacitor excellent in vibration resistance and temperature change can be obtained.

Sectional view of an electrolytic capacitor according to an embodiment of the present invention Enlarged view of part A of the capacitor element 12 shown in FIG. The elements on larger scale of the cross section of capacitor element 12 showing other examples in an embodiment of the invention. (A) A plan view of an anode foil according to another embodiment of the present invention, (b) a partially enlarged view of a cross section BB' of the anode foil shown in FIG. 4(a), (c) FIG. 4(a). The CC' partial cross section figure of the anode foil shown.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in the drawings, the aspect ratios of some dimensions are changed for easier understanding.

(Embodiment 1)
FIG. 1 is a sectional view of an electrolytic capacitor according to an embodiment of the present invention. FIG. 2 is an enlarged view of part A of the capacitor element 12 shown in FIG. FIG. 3 is a partially enlarged view of a cross section of a capacitor element 12 showing another example of the embodiment of the present invention.

As shown in FIG. 1, the electrolytic capacitor 1 of the present invention has a structure in which a capacitor element 12 is enclosed in an exterior body 15.

Capacitor element 12 includes a winding element 11 in which an anode foil 21, a cathode foil 22, and a separator 23 each having a dielectric layer on the surface thereof are wound and stacked, and lead tab terminals 16 and 17.

The separator 23 is sandwiched and wound between the anode foil 21 and the cathode foil 22.

The lead tab terminal 16 is connected to the anode foil 21, and the lead tab terminal 17 is connected to the cathode foil 22 so as to be led out from one end face of the winding element 11 to the outside of the winding element 11.

The capacitor element 12 is enclosed in an exterior body 15 including a case 13 and a sealing body 14, and the lead tab terminals 16 and 17 are led out to the outside through a through hole 14 a provided in the sealing body 14.

The electrolyte 19 is, for example, a solid electrolyte such as an electrolytic solution or a conductive polymer, but is not particularly limited, and is adhered to the anode foil 21, the cathode foil 22, and the separator 23, or between the anode foil 21 and the separator, the cathode foil 22 and the separator. It exists between 23 and.

An insulating resin layer 18 is provided on at least a part of the surface of the end portion of the anode foil 21 in the width direction or at least a part of the surface of the end portion of the anode foil 21 in the longitudinal direction. The layer 18 overlaps the cathode foil 22 via the separator 23 (portion shown in D of FIG. 2 or FIG. 3).

As described above, the insulating resin layer 18 is provided on the surface of the end portion of the anode foil 21, and the insulating resin layer 18 is overlapped with the cathode foil 22 via the separator 23, so that this overlap is achieved. In the portion, the pressure for suppressing each of the anode foil 21, the separator 23, and the cathode foil 22 is increased, so that the anode foil 21, the separator 23, and the cathode foil 22 are less likely to be displaced from each other, and as a result, violent vibration and large temperature change are prevented. It is possible to obtain an electrolytic capacitor in which leakage current characteristics and insulation are less likely to deteriorate even in a use environment in which it is continuously or repeatedly subjected.

Further, the insulating resin layer 18 provided on the surface of the end portion in the width direction on one surface of the anode foil 21 is connected to the insulating resin layer 18a provided on the end surface in the width direction of the anode foil 21, Further, the insulating resin layer 18a provided on the end face in the width direction of the anode foil 21 is connected to the insulating resin layer 18 provided on the end face in the width direction on the other face of the anode foil 21. There is.

Thus, the insulating resin layer 18 provided on the surface of the end portion in the width direction on one surface of the anode foil 21, and the insulating resin layer 18a provided on the end surface in the width direction of the anode foil 21. Is connected, the adhesion of the insulating resin layer to the anode foil 21 can be increased, and the reliability of the electrolytic capacitor can be increased. Then, the insulating resin layer 18 provided on the surface of the end portion in the width direction on one surface of the anode foil 21, the insulating resin layer 18a provided on the end surface in the width direction of the anode foil 21, and the anode By being connected to the insulating resin layer 18 provided on the surface of the end portion in the width direction on the other surface of the foil 21, the adhesive force of the insulating resin layer to the anode foil 21 can be further increased.

More specifically,
The anode foil 21 is roughened by etching a metal foil made of a valve metal such as aluminum, and a dielectric layer is provided on the surface by a chemical conversion treatment or the like. On the other hand, the cathode foil 22 is made of metal such as aluminum.

The cathode foil 22 may be provided with a chemical conversion coating on the surface of a metal such as aluminum, or with a coating of a different metal or a non-metal. Examples of the dissimilar metals and non-metals include metals such as titanium and non-metals such as carbon.

The material of the lead tab terminals 16 and 17 is not particularly limited as long as it is a conductive material, but at least the joint portion with the anode foil 21 and the cathode foil 22 is made of the same material as the anode foil 21 and the cathode foil 22. Is preferred.

The surfaces of the lead tab terminals 16 and 17 may be subjected to chemical conversion treatment. Further, the portions of the lead tab terminals 16 and 17 that come into contact with the sealing body 14 may be covered with a resin material.

The separator 23 contains a cellulose fiber. Cellulose fiber is a general term for fibers mainly composed of cellulose. In addition to natural fibers obtained from natural materials such as Manila hemp, esparto, hemp, kraft pulp, and bamboo, these natural materials are once dissolved. It contains recycled fibers such as rayon obtained by spinning, and semi-synthetic fibers such as acetate obtained by subjecting natural materials to chemical treatment. The separator 23 may include fibers other than cellulose fibers, for example, polyethylene terephthalate, vinylon, polyamide fibers (aliphatic polyamide fibers such as nylon and aromatic polyamide fibers such as aramid), and the like.

Examples of the resin material forming the insulating resin layers 18 and 18a include resins such as silicon, epoxy, fluorine, acrylic, aramid, polyethylene, polypropylene, polyethylene terephthalate, and rubber.

The hardness of the insulating resin layers 18 and 18a is preferably E20 to A90 in a durometer. By setting the hardness of the insulating resin layers 18 and 18a to be E20 to A90 in the durometer, it is possible to improve the effect of suppressing the displacement of the anode foil 21, the cathode foil 22 and the separator 23 that form the capacitor element 12. .. When the hardness of the insulating resin layers 18 and 18a is lower than this range, the slipperiness of the anode foil 21 is deteriorated and wrinkles are likely to occur during winding, and when the hardness is higher than this range, the rigidity of the anode foil 21 is increased. Becomes too high and winding becomes difficult.

When a solid electrolyte is used as the electrolyte, the solid electrolyte may contain a conductive polymer. Examples of the conductive polymer include polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, polyphenylene, polyphenylene vinylene, polyacene, and polythiophene vinylene. These may be used alone or in combination of two or more, and may be a copolymer of two or more monomers. In the present specification, polypyrrole, polythiophene, polyfuran, polyaniline and the like mean polymers having a basic skeleton such as polypyrrole, polythiophene, polyfuran and polyaniline, respectively. Therefore, polypyrrole, polythiophene, polyfuran, polyaniline and the like may also include their respective derivatives. For example, polythiophene includes poly(3,4-ethylenedioxythiophene) and the like.

The conductive polymer may include a dopant. Examples of the dopant include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polyacryl sulfonic acid, polymethacryl sulfonic acid, poly(2-acrylamido-2-methylpropane sulfonic acid), polyisoprene sulfonic acid, polyacrylic. Examples include anions such as acids. Of these, polyanions derived from polystyrene sulfonic acid are preferable. These may be used alone or in combination of two or more. Further, these may be a polymer of a homomonomer or a copolymer of two or more kinds of monomers.

The conductive polymer also functions as the cathode of the electrolytic capacitor.

Further, an electrolytic solution may be used instead of the solid electrolyte. The electrolytic solution is prepared by dissolving a solute in an organic solvent. As the organic solvent, alcohols, aprotic amide solvents, lactones, sulfoxides and the like can be used. Examples of alcohols include methanol, ethanol, propanol, butanol, cyclobutanol, cyclohexanol, ethylene glycol, propylene glycol, glycerin, methyl cellosolve, ethyl cellosolve, methoxypropylene glycol, and polycondensates of glycols. Examples of the amide solvent include N-methylformamide, N,N-dimethylformamide, N-ethylformamide, N,N-diethylformamide, N-methylacetamide and N,N-dimethylacetamide. Examples of lactones include γ-butyrolactone, β-butyrolactone, α-valerolactone, γ-valerolactone, and the like. Examples of sulfoxides include sulfolane, 3-methylsulfolane, dimethylsulfoxide, and the like.

The base component of the electrolyte component that is a solute is a compound having an alkyl-substituted amidine group, and examples thereof include an imidazole compound, a benzimidazole compound, and an alicyclic amidine compound (pyrimidine compound, imidazoline compound). The quaternary ammonium of the compound having an alkyl-substituted amidine group can also be used as the base component of the electrolyte component, and the quaternary ammonium of the compound having an alkyl-substituted amidine group can be an alkyl group having 1 to 11 carbon atoms or Examples thereof include imidazole compounds quaternized with an arylalkyl group, benzimidazole compounds, alicyclic amidine compounds (pyrimidine compounds, imidazoline compounds) and the like. As the base component, ammonium, primary amine (methylamine, ethylamine, propylamine, butylamine ethylenediamine, monoethanolamine, etc.), secondary amine (dimethylamine, diethylamine, dipropylamine, ethylmethylamine, diphenylamine, diethanolamine, etc.) Alternatively, a tertiary amine (trimethylamine, triethylamine, tributylamine, 1,8-diazabicyclo(5,4,0)-undecene-7, triethanolamine, etc.) may be used.

Moreover, as the acid component of the electrolyte component, a saturated carboxylic acid, an unsaturated carboxylic acid, an aromatic carboxylic acid or the like, which is an aliphatic carboxylic acid, can be used. Examples of the saturated aliphatic carboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,6-decanedicarboxylic acid, 5,6-decanedicarboxylic acid. Formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, lauric acid, myristic acid, stearic acid, and behenic acid. Examples of the aliphatic unsaturated carboxylic acid include maleic acid, fumaric acid, icotanic acid, acrylic acid, methacrylic acid and oleic acid. Examples of the aromatic carboxylic acid include phthalic acid, salicylic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, benzoic acid, resorcinic acid, cinnamic acid and naphthoic acid. In addition to these carboxylic acids, nitro derivatives or sulfonic acid derivatives of carboxylic acids, phosphoric acid derivatives or boric acid derivatives which are inorganic acids can be used as the acid component of the electrolyte.

The electrolytic solution has a function of repairing a defective portion of the dielectric film by entering a void inside the separator 23 or a hole formed by an etching pit of the anode foil 21.

Moreover, you may use together a solid electrolyte and an electrolytic solution. By using the solid electrolyte and the electrolytic solution in combination, the ESR characteristic and the withstand voltage characteristic of the electrolytic capacitor can be improved.

The outer package 15 closes the capacitor element 12 so that the ends of the lead tab terminals 16 and 17 drawn out from the capacitor element 12 are led to the outside.

The exterior body 15 has a case 13 and a sealing body 14. The case 13 houses the capacitor element 12.

The sealing body 14 is provided with a through hole 14a through which the lead tab terminals 16 and 17 are inserted. The sealing body 14 is arranged in the opening of the case 13 and seals the opening of the case 13 by compressing the outer peripheral surface of the case 13 with the drawing portion 13a.

For the sealing body 14, a rubber material such as ethylene propylene rubber or butyl rubber which is a copolymer of isobutyl and isoprene, or a resin material such as an epoxy resin can be used.

The case 13 is made of metal. From the viewpoint of weight reduction, the case 13 is preferably made of aluminum.

Next, a method of manufacturing the electrolytic capacitor according to the first embodiment of the present invention will be described.

(Preparation of electrode foil)
The anode foil 21 is roughened by etching a metal foil made of a valve metal such as aluminum, and is further subjected to chemical conversion treatment to form a dielectric oxide film on the surface of the roughened metal foil. As the etching treatment, for example, a direct current electrolysis method or an alternating current electrolysis method may be applied. As the chemical conversion treatment, for example, a voltage may be applied while the metal foil is immersed in a chemical conversion liquid such as an ammonium adipate solution.

The metal foil having the dielectric oxide film formed by the chemical conversion treatment is slit into a predetermined width if necessary.

As the cathode foil 22, a metal foil may be used as it is or a surface thereof may be roughened before use.
As a method of roughening the surface, etching treatment can be applied as in the case of the anode foil 21.

The metal foil used for the cathode foil 22 is also slit into a predetermined width if necessary.

(Preparation of separator)
A separator substrate 24 containing fibers such as natural fibers, recycled fibers, semi-synthetic fibers, and synthetic fibers may be used as it is as the separator 23, or the separator substrate 24 is impregnated with a solid electrolyte 25 such as a conductive polymer. The adhered one may be used as the separator 23. This separator 23 is also slit into a predetermined width if necessary.

(Formation of insulating resin layer on anode foil)
As a method of forming the insulating resin layers 18 and 18a on the anode foil 21, for example, a coating method using a roll can be applied.

As an example, a method of gravure coating using a gravure roll will be described.

First, a resin liquid obtained by dissolving a resin to be the insulating resin layers 18 and 18a in a solvent is attached to the surface of the rotating gravure roll. At this time, since the resin liquid is received by a plurality of minute cells that are regularly arranged on the surface of the gravure roll and have substantially the same volume, almost the same amount of resin liquid is attached to any part of the surface of the gravure roll. ..

Then, while contacting the surface of the end portion in the width direction of the anode foil 21 with the surface of the gravure roll to which the resin liquid has adhered, the anode foil is caused to run in the same direction as the rotation direction of the gravure roll or in the opposite direction. At this time, a certain amount of the resin liquid adhering to the surface of the gravure roll is transferred and applied from the surface of the gravure roll to the surface of the end portion in the width direction of the anode foil.

After that, the solvent component is removed from the resin liquid applied to the anode foil and dried to form the insulating resin layer 18 on the end surface and the end surface in the width direction of the anode foil.

When the resin forming the insulative resin layer 18 is a thermosetting resin or an ultraviolet curable resin, a curing means such as heating or ultraviolet irradiation may be applied after removing the solvent.

In the method by gravure coating as described above, the steps from coating the resin liquid to the end face in the width direction of the anode foil, removing the solvent from the resin liquid and drying the resin liquid are wound into a roll. The insulating resin layer 18 can be continuously formed on the surface of the end portion of the anode foil 21 if it is successively carried out during the transportation until the long anode foil 21 is unwound and then rewound. it can.

When the insulating resin layer 18 is formed on the surface of the end portion in the width direction of the anode foil 21 as described above, as shown in FIG. 1, the insulating resin layer formed on the anode foil 21 is used. The dimensions of the anode foil 21 and the cathode foil 22 in the width direction and the dimensions of the insulating resin layer 18 in the width direction (width direction of the anode foil 21) are controlled so that 18 overlaps with the cathode foil 22.

When the insulating resin layer 18 is formed on the surface of the end portion of the anode foil on the opposite side in the width direction of the end portion where the insulating resin layer 18 is formed, or when the insulating resin layer 18 is formed. The above method may be applied to the case where the insulating resin layer 18 is formed on the end of the back surface of the above surface.

When the insulating resin layer 18a is provided on the end face in the width direction of the anode foil 21, the kind of solvent or the composition of the resin liquid is controlled so as to reduce the surface tension of the resin liquid applied to the anode foil 21. Then, the resin liquid applied to the end of the anode foil 21 may wrap around from the surface of the end of the anode foil 21 to the end face in the width direction of the anode foil 21.

(Formation of winding element)
After connecting lead tab terminals to the anode foil 21 on which the insulating resin layer 18 is formed and the cathode foil 22, the insulating resin layer 18 formed on the surface of the end portion in the width direction of the anode foil 21 and the cathode The wound element 11 is formed by winding the one in which the anode foil 21, the separator 23, the cathode foil 22 and the second separator 23 are arranged so that the end of the foil 22 overlaps with the separator 23.

When the insulating resin layer 18 is formed on the surface of the end portion of the anode foil 21 in the longitudinal direction, in the step of forming the winding element 11, the winding start or the winding of the anode foil 21 before winding is performed. The end surface in the longitudinal direction of the end is brought into contact with a felt or a porous body containing a resin solution in which an insulating resin is dissolved in a solvent, and the resin solution is applied to the longitudinal end portion of the anode foil 21. After that, the solvent in the applied resin liquid is removed and dried, whereby the insulating resin layer 18 can be formed.

(Formation of capacitor element)
When the solid electrolyte is used as the electrolyte, the capacitor element 12 may be formed by using the separator 23 that is impregnated with the solid electrolyte in advance, or the solid electrolyte may be dissolved or wound around a liquid agent in which fine particles of the solid electrolyte are dispersed. The element 11 may be dipped and a solid electrolyte may be deposited.

When an electrolytic solution is used as the electrolyte, the winding element 11 may be impregnated with the electrolytic solution to form the capacitor element 12, and then the capacitor element 12 may be housed in the case 13. The electrolytic solution may be injected into the case 13 after housing the same in the case 13, or the winding element 11 may be housed in the case 13 after the electrolytic solution is injected into the case 13.

(Formation of electrolytic capacitor)
The sealing body 14 is arranged in the opening of the case 13 in which the capacitor element 12 is housed, the lead tab terminals 16 and 17 are led out from the through hole 14a of the sealing body 14, and sealed by the drawn portion 13a to form the electrolytic capacitor 1. Form.

Embodiment 2
Next, a second embodiment of the present invention will be described.

FIG. 4A is a plan view showing anode foil 21 forming capacitor element 12 and lead tab terminal 16 connected to anode foil 21 of electrolytic capacitor 1 according to Embodiment 2 of the present invention. .. FIG. 4B is a partially enlarged view of a cross section of the connection portion between the anode foil 21 and the lead tab terminal 16 shown in FIG. FIG. 4C is a partial cross-sectional view of a cross section of the connection portion between the anode foil 21 and the lead tab terminal 16 shown in FIG.

As shown in FIGS. 4A, 4B, and 4C, an insulating resin layer 18 is provided on the surface of the end portion in the width direction of the anode foil 21. The insulating resin layer 18 is also provided on the surface of the end portion of the anode foil 21 in the longitudinal direction. These insulative resin layers 18 extend from the surface of one end of the anode foil 21 through the end surface of the anode foil 21 to the other end surface of the anode foil 21. The insulating resin layer 18 provided in the same manner and the insulating resin layer 18 provided on the other surface are the insulating resin layer provided on the end face in the width direction of the anode foil. It is connected through 18a.

The lead tab terminal 16 is connected to the surface of the anode foil 21 by a needle crimping portion 26. An insulating resin layer 38 is also provided on the surface of the lead tab terminal 16 at the connection between the anode foil 21 and the lead tab terminal 16. Further, an insulating resin layer 38b is also formed on the portion of the other surface of the other side of the anode foil 21 to which the lead tab terminals 16 are connected, which is opposite to the connection portion between the anode foil 21 and the lead tab terminals 16. It is provided.

With the above configuration, the insulating resin layers 18, 38 and 38b overlap with the cathode foil 22 via the separator 23, and in the overlapping portion, the anode foil 21, the separator 23, By increasing the pressure that suppresses each of the cathode foils 22, the anode foil 21, the separator 23, and the cathode foil 22 are less likely to shift from each other, and as a result, the operating environment in which severe vibrations and large temperature changes are continuously or repeatedly received. Also in the above, an electrolytic capacitor can be obtained in which leakage current characteristics and insulation are not deteriorated.

Next, a method of manufacturing the electrolytic capacitor according to the second embodiment will be described.

The same materials as those in the first embodiment can be used for the materials of the anode foil 21, the cathode foil 22, and the insulating resin layers 18, 18a, 38, 38b.

As a method of forming the insulating resin layer 18 on the surface of the end portion of the anode foil 21 in the width direction, the same method as in Embodiment 1 can be applied.

As a method of forming the insulating resin layer 18 on the surface of the end portion of the anode foil 21 in the longitudinal direction, the same method as in Embodiment 1 can be applied.

A method of providing an insulating resin layer 38 on the surface of the lead tab terminal 16 in the connection portion between the anode foil 21 and the lead tab terminal 16, and the other side of the anode foil 21 to which the lead tab terminal 16 is connected As a method of providing the insulating resin layer 38b on the portion of the surface facing the connecting portion with the lead tab terminal 16 in the step of forming the winding element 11, the lead tab previously connected to the anode foil 21 before winding is formed. An insulating resin is used as a solvent on the surface of the terminal 16 and the other surface of the anode foil 21 to which the lead tab terminal 16 is connected, which is opposite to the other surface of the anode foil 21 and which faces the connection portion with the lead tab terminal 16. After transferring the resin liquid by bringing it into contact with a felt or a porous body containing the dissolved resin liquid, the solvent or dispersion medium in the transferred resin liquid is removed, and the anode foil 21 is dried. The surface of the lead tab terminal 16 connected in advance and the part of the other surface opposite to the one surface of the anode foil 21 to which the lead tab terminal 16 is connected opposite to the connection part with the lead tab terminal 16 are insulated. The resin layer 38 can be formed.

The same method as that of the first embodiment can be applied to the step of forming the capacitor element 12 and the step of encapsulating the capacitor element 12 in the exterior body to form an electrolytic capacitor.

Next, examples will be described. The present invention is not limited to these examples.

(Example 1)
Example 1 will be described.

The anode foil used was one in which the surface of an aluminum foil having a thickness of 115 μm was roughened by etching treatment, a dielectric film was formed on the roughened surface by anodizing treatment, and slit to a predetermined width.

Silicone rubber (trade name RVT silicone rubber manufactured by Shin-Etsu Chemical Co., Ltd.) was used as a material for the insulating resin layer.

A resin solution prepared by dissolving and diluting a silicone rubber material, which is the material for the insulating resin layer, in a solvent is applied by gravure coating to the surface of one end of the anode foil in the width direction, The solvent was removed and dried to form an insulating resin layer. An insulating resin layer was also formed on the surface of the end portion in the width direction of the other surface of the anode foil in the same manner as on the one surface of the anode foil.

At this time, an insulating resin layer was also formed on the end face in the width direction of the anode foil so as to be connected to the insulating resin layer formed on the surface of the end portion of the anode foil.

The insulating resin layer formed on the surface of the end portion in the width direction of the anode foil had a width of 0.4 mm from the end face in the width direction of the anode foil and a thickness of 15 μm. The insulating resin layer formed on the end face in the width direction of the anode foil had a thickness of 12 μm from the end face in the width direction of the anode foil.

The hardness of the insulating resin layer formed on the end portion of the anode foil was A50 in the durometer.

As the cathode foil, an aluminum foil having a thickness of 115 μm was used, and lead tab terminals made of aluminum were respectively connected to the cathode foil and the anode foil on which the insulating resin layer was formed by needle caulking. Then, the insulating resin layer formed on the surface of the end portion in the width direction of the anode foil and the end portion in the width direction of the cathode foil overlap each other with a width of 0.3 mm through a separator made of natural fiber having a thickness of 60 μm. Then, the anode foil, the separator and the cathode foil were superposed and wound to form a wound element.

Then, the winding element was coated with a conductive polymer as a solid electrolyte to form a capacitor element.

As the conductive polymer adhered to the wound element, poly3,4-ethylenedioxythiophene (hereinafter referred to as PEDOT) containing polystyrene sulfonic acid as a dopant was used.

The fine particles of PEDOT are immersed in a dispersion liquid in which a dispersion medium containing water as a main component is dispersed so that the entire wound portion of the wound element is immersed, and the immersion state is maintained for 10 minutes under a reduced pressure of 50 kPa. The wound element was then impregnated with the dispersion liquid.

The wound element was taken out of the dispersion and heated in a high temperature bath to remove the dispersion medium in the dispersion impregnated in the wound element.

A capacitor element was formed by the above operation.

Then, the capacitor element coated with the conductive polymer was housed in a bottomed case together with an electrolytic solution prepared by dissolving ammonium 1,6-decanedicarboxylate in ethylene glycol, and sealed to produce an electrolytic capacitor. did.

The bottomed case used as the outer case was made of aluminum.

The sealing body for sealing the open end of the bottomed case was made of butyl rubber.

In Example 1, an electrolytic capacitor having a rated voltage of 35 V and a capacity of 47 μF was manufactured.

(Example 2)
In Example 2, an electrolytic capacitor was produced in the same manner as in Example 1 except that the hardness of the insulating resin layer in the durometer was set to E20.

(Example 3)
In Example 3, an electrolytic capacitor was manufactured in the same manner as in Example 1 except that the hardness of the insulating resin layer in the durometer was set to A90.

(Example 4)
In Example 4, an insulating resin layer was formed on the surface of the end portion in the width direction on one surface of the anode foil, and the insulating resin layer was also formed on the surface of the end portion in the longitudinal direction on one surface of the anode foil. Formed. Furthermore, an insulating resin layer is also formed on the surface of the end portion in the width direction on the other surface of the anode foil and on the surface of the end portion in the longitudinal direction on the other surface of the anode foil. The insulative resin layer formed on the other side and the insulative resin layer formed on the other surface were connected via the insulative resin layer formed on the end face of the anode foil.

Then, the lead tab terminal 16 was connected to the surface of the anode foil by needle crimping, and an insulating resin layer was formed on the surface of the lead tab terminal at the connecting portion between the anode foil and the lead tab terminal. At this time, the thickness of the insulating resin layer formed on the surface of the lead tab terminal was 20 μm.

Further, an insulating resin layer was formed on a portion of the other surface opposite to the one surface of the anode foil to which the lead tab terminals were connected, opposite to the connection portion with the lead tab terminals. The thickness of the insulating resin layer at this time was 20 μm.

The hardness of the insulating resin layer formed in this Example 4 was A60 in the durometer.

A method of manufacturing the electrolytic capacitor according to the fourth embodiment will be described.

The same materials as those used in Example 1 were used for the anode foil, the cathode foil, the insulating resin layer, and the like.

As the method of forming the insulating resin layer on the surface of the end portion in the width direction of the anode foil, the same method as in Example 1 was applied.

The same method as in Example 1 was applied as a method for forming the insulating resin layer on the surface of the end portion in the longitudinal direction of the anode foil.

Insulation is applied to the surface of the lead tab terminal at the connection between the anode foil and the lead tab terminal, and to the part of the other surface opposite the one side of the anode foil to which the lead tab terminal is connected, opposite the connection to the lead tab terminal. As a method of forming a conductive resin layer, in the step of forming a wound element, the surface of the lead tab terminal previously connected to the anode foil before winding, and one surface of the anode foil to which the lead tab terminal is connected. After transferring the resin liquid, contact the felt on the other surface of the other side, which is opposite to the connection part with the lead tab terminal, with the resin liquid in which the insulating resin is dissolved in the solvent, and transfer the resin liquid. The insulating resin layer was formed by removing the solvent or the dispersion medium in the transferred resin liquid.

The same method as in Embodiment 1 was applied to the step of applying a conductive polymer to the wound element to form a capacitor element and the step of encapsulating the capacitor element in an outer package to form an electrolytic capacitor.

(Example 5)
In Example 5, the insulating resin layer was not formed on the portion of the other surface of the anode foil, to which the lead tab terminals were connected, opposite to the one surface, which faced the connection portion with the lead tab terminals. An electrolytic capacitor was produced in the same manner as in Example 4 except that the difference was different.

Next, a comparative example will be described.

(Comparative Example 1)
In Comparative Example 1, an electrolytic capacitor was produced in the same manner as in Example 1 except that the insulating resin layer was not formed on the anode foil.

(Comparative example 2)
In Comparative Example 2, an insulating resin layer was formed on the anode foil in the same manner as in Example 1 except that the hardness of the insulating resin layer in the durometer was set to E17. Since the insulating resin layer was too soft, the slipperiness of the anode foil was poor and the wound element could not be formed.

(Comparative example 3)
In Comparative Example 3, an insulating resin layer was formed on the anode foil in the same manner as in Example 1 except that the hardness of the insulating resin layer in the durometer was set to A95, but an attempt was made to manufacture an electrolytic capacitor. However, the wound element could not be formed because the insulating resin layer was too hard.

(Evaluation of electrolytic capacitors)
The electrolytic capacitors produced in the examples and comparative examples were evaluated.

As an evaluation method, 100 electrolytic capacitors produced in each of the examples and comparative examples were subjected to a vibration test, and a leakage current value after the vibration vibration test was 5 times or more of the leakage current value before the test was determined as NG determination. I counted.

The conditions for the vibration test are
Frequency is 10Hz-55Hz, 1 minute round trip/1 minute/Cycle,
The total amplitude is 1.5 mm,
The vibration direction and time are 2 hours each in 3 directions orthogonal to each other, for a total of 6 hours.

The evaluation results are shown in Table 1.

As shown in Table 1, in Comparative Example 1, the number of NG judgments in which the leakage current value after the vibration test was 5 times or more the leakage current value before the test was 7 out of 100 tests. On the other hand, in the electrolytic capacitors of Examples 1 to 5, the number of NG judgments in which the leakage current value after the vibration test was 5 times or more the leakage current value before the test was 3 or less out of 100 tests. Therefore, the improvement of the earthquake resistance according to the present invention is recognized.

Further, in Examples 4 and 5, the number of NG judgments in which the leakage current value after the vibration test was 5 times or more the leakage current value before the test was 0 to 1, and the anode foil and the lead tab terminal were By forming an insulative resin layer on the surface of the lead tab terminal in the connection part of, and in addition to the one surface of the anode foil to which the lead tab terminal is connected and the other surface on the opposite side, It can be seen that the vibration resistance can be further improved by forming the insulating resin layer in the portion facing the connection portion.

The present invention can be applied to an electrolytic capacitor provided with an anode body, a cathode body and a separator.

DESCRIPTION OF SYMBOLS 1 Electrolytic capacitor 11 Winding element 12 Capacitor element 13 Case 13a Drawing part 14 Sealing body 14a Through hole 15 Exterior body 16, 17 Lead tab terminals 18, 18a, 38, 38b Insulating resin layer 19 Electrolyte 21 Anode foil 22 Cathode foil 23 Separator 26 Needle swaged part

Claims (4)

A capacitor element in which an anode foil and a cathode foil provided with a dielectric layer on the surface are stacked via a separator, and an electrolyte, and at least a part of an end portion in the width direction of the anode foil, or an end in the longitudinal direction. An insulating resin layer is provided on at least a part of the portion, the insulating resin layer is overlapped with at least a part of the cathode foil via the separator,
A lead tab terminal is connected to one surface of the anode foil, and a portion of the other surface of the anode foil opposite to the one surface to which the lead tab terminal is connected and facing the connecting portion of the lead tab terminal. An electrolytic capacitor characterized in that an insulating resin layer is provided on. Wherein the one surface of the anode foil is connected lead tab terminal, the electrolytic capacitor according to claim 1, wherein the insulating resin layer is provided on at least a portion of a surface of the lead tab terminal. The hardness of the insulating resin layer is in the range of E20 to A90 in a durometer, and the electrolytic capacitor according to claim 1 or 2 . The capacitor element has a wound element formed by winding through the separator and the cathode foil and the anode foil, an electrolytic capacitor according to any one of claims 1 to 3.

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