JPH05190397A - Method of manufacturing solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To precisely mask a positive pole leader part when forming a solid electrolyte comprising a conductive high molecule matter. CONSTITUTION:After sealing parts 14, 14 comprising adhesive resin are provided in a positive pole leader part 11, a masking tape 15 is adhered to the sealing parts 14, 14 to mask the positive pole leader part 11. This masking tape 15 is separated in any process after forming a chemical oxide polymerized film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a solid electrolytic capacitor, and more particularly to a method for manufacturing a solid electrolytic capacitor provided with a solid electrolyte made of a conductive polymer material.

[0002]

2. Description of the Related Art In a solid electrolytic capacitor, by using a conductive polymer substance (for example, polypyrrole) as its solid electrolyte, the equivalent series resistance and leakage current can be reduced as compared with a solid electrolytic capacitor using manganese dioxide as a solid electrolyte. Can be smaller.

When manufacturing a solid electrolytic capacitor of this type, as shown in FIGS. 10 and 11, first, a metal plate capable of forming a dielectric oxide film, for example, a strip-shaped aluminum foil 1 is prepared. , The same aluminum foil 1 is formed in a comb shape, and a plurality of protrusions 2, which will be the capacitor element foil, are continuously provided on one side thereof.

A masking layer 3 made of a resin coat or resin tape having water repellency and electrical insulation is provided on the base side of each protrusion 2 to separate the protrusion 2 from the anode lead-out portion 1a. A chemical oxidation polymerization film 4 is formed on each protrusion 2 by a chemical polymerization method.

Next, by dipping in an electrolytic polymerization solution, an electrolytic polymerization film 5 made of a conductive polymer substance is formed on the chemically oxidized polymerization film 4 by an electrolytic polymerization method. In this case, electrolytic polymerization tank 6
The side serves as a cathode, and an anode side power supply terminal 7 is brought into contact with the chemically oxidized polymer film 4 to apply a polymerization voltage.

Thereafter, although not shown, a carbon layer and a silver layer as a cathode extraction layer are sequentially formed on the electropolymerized film 5. Thus, in the actual manufacturing process, for example, 50 capacitor elements corresponding to the number of the protrusions 2 are obtained from one aluminum foil.

[0007]

In the above-mentioned conventional example, a masking layer 3 is provided on the base side of the protrusion 2 to separate the protrusion 2 from the anode lead-out portion 1a, and the chemical polymerization liquid is used as an anode during chemical polymerization. Although it is arranged so as not to crawl up to the drawer portion 1a side, it is necessary to strictly control the liquid surface or to widen the width of the masking layer 3 for that purpose.

However, if the liquid level is strictly controlled, the yield will be reduced. On the other hand, the masking layer 3
If the width of the element foil is widened, the effective area of the element foil is reduced accordingly, and the electrostatic capacitance is reduced. Of course, in order to maintain the desired electrostatic capacity, it is sufficient to make the projection 2 itself large, but this causes a problem that the product size becomes large.

Further, as shown in FIG. 11, in carrying out electrolytic polymerization, the anode side power supply terminal 7 is brought into contact with the chemically-oxidized polymerized film 4, but if the contact pressure is too strong, the anodized film is formed. Will be damaged and short defects will occur frequently.

Furthermore, when a resin tape is used as the masking layer 3, the adhesiveness is not sufficient, and a chemical polymerization liquid, an electrolytic polymerization liquid, or A cathode lead-out material such as carbon or silver paste will soak in, causing a short circuit defect.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and its structural feature is that a dielectric oxide film is formed on a valve-action metal foil of a predetermined width that has been etched in advance. After the strip-shaped anode lead-out portion is left on the valve action metal foil and a plurality of projections used as capacitor element foils are continuously provided on at least one side thereof in a comb-tooth shape, the anode lead-out portion is provided along the length direction thereof. At least two sealing parts made of adhesive resin are applied in a ridge shape at a predetermined interval, and a masking tape is attached through the sealing parts so as to cover the anode extraction part. The purpose is to form an oxidative polymerization film, and then immerse it in an electrolytic polymerization solution to form an electrolytic polymerization film made of a conductive polymer substance on the chemically oxidized polymerization film by the electrolytic polymerization method.

The masking tape is finally removed. The removal is carried out after the formation of the chemically-oxidized polymerized film, the formation of the electrolytically polymerized film, or the carbon layer and the silver layer as the cathode extraction layer on the electrolytically polymerized film. It may be after the formation.

Further, in the manufacturing method of the present invention, a dielectric oxide film is formed on a valve-action metal foil having a predetermined width that has been etched in advance, and a strip-shaped anode lead-out portion is left on the valve-action metal foil on both sides thereof. After a plurality of protrusions used as capacitor element foils are continuously formed in a comb shape, at least two seal portions made of an adhesive resin are provided along the length direction of the anode lead portion at predetermined intervals. And apply a masking tape through the seal to cover the anode extraction part, and then form a chemically oxidized polymer film by a chemical polymerization method, and then dip it in an electrolytic polymerization solution to form an electrolytic polymer. An electrolytically polymerized film made of a conductive polymer material is formed on the chemically oxidized polymerized film by a conventional method, and a carbon layer and a silver layer as a cathode extraction layer are further formed on the electrolytically polymerized film. The masking tape is removed in any step after the formation of the oxide polymer film, and the capacitor elements formed on both sides of the anode lead portion are laminated by bending the anode lead portion. ..

In the chemical polymerization, a valve metal foil such as an aluminum etched foil is first immersed in an aqueous solution containing a monomer and a solvent, and the monomer is introduced into the pores of the aluminum etched foil. The monomer concentration is 5 to 50 wt%, preferably 20 to 40 wt%, and the solvent concentration is 5 to 50 wt%,
20 to 40 wt% is preferable.

Then, it is immersed in an aqueous solution containing an oxidizing agent and a supporting electrolyte to polymerize the monomers on the surface of the aluminum etched foil and in the pores into a conductive polymer. Incidentally, the monomer and the oxidant may be applied by a method such as coating or spraying, which allows the monomer and the oxidant to be uniformly attached, instead of dipping.

The electrolytic polymerization solution comprises a monomer, a supporting electrolyte and a solvent. Monomer concentration is 0.01-5.0m
ol / l, preferably 0.05 to 3.0 mol / l. The concentration of the supporting electrolyte is 0.01 to 5.0 mol / l,
It is preferably 0.05 to 3.0 mol / l.

Heterocyclic compounds such as pyrrole, thiophen, furan and aniline are used as the monomer.

Examples of the oxidizing agent include halogen such as iodine, bromine and bromine iodide, arsenic pentafluoride, antimony pentafluoride, silicon tetrafluoride, phosphorus pentachloride, phosphorus pentafluoride, aluminum chloride and molybdenum chloride. Proton acids such as metal halides, sulfuric acid, nitric acid, fluorosulfuric acid, trifluoromethane sulfuric acid and chlorosulfuric acid, sulfur trioxide, oxygen-containing compounds such as nitrogen dioxide, persulfates such as ammonium persulfate, hydrogen peroxide, peracetic acid, difluoro Peroxides such as sulfonyl peroxide, ferric nitrate, ferric sulfate
An iron compound such as iron, a cupric nitrate, a copper compound such as copper sulfate, or the like is used.

Examples of the supporting electrolyte include sulfonic acids such as P-toluenesulfonic acid, naphthalenesulfonic acid and benzenesulfonic acid, carboxylic acids such as benzoic acid, adipic acid, oxalic acid and phthalic acid, phenylphosphoric acid and naphthylphosphoric acid. Boric acid such as phosphoric acid or phenylboric acid may be used alone or in combination.

As the solvent, in addition to water, a protic solvent such as ethanol or methanol and an aprotic solvent such as acetonitrile, propylene carbonate or N, N-dimethylformamide may be used alone or in combination. The type of solvent is appropriately selected depending on the supporting electrolyte.

The valve-action metal foil used is made of aluminum, tantalum, titanium, niobium, etc.
A thin foil of 300 μm is preferred.

The adhesive resin used for the seal portion is preferably an epoxy resin or a silicone resin having a curing temperature of about 100 to 150 ° C.

The masking tape is a resin film of polyethylene terephthalate, polypropylene, silicone resin, fluorine resin, polyester, polyimide or the like as a base material, and a foaming adhesive agent such as a rubber-based, acrylic-based or silicon-based adhesive agent. It is preferable to apply a product containing a foaming agent.

In this foamable pressure-sensitive adhesive, the foaming agent in the pressure-sensitive adhesive is foamed by heating, resulting in unevenness on the pressure-sensitive adhesive surface. Therefore, the adhesive area with the adherend is significantly reduced, and the adhesive force is almost lost.

As the foaming agent, azo compounds such as 2,2'-azobisisobutyronitrile and azohexahydrobenzonitrile, benzenesulfohydrazide, benzene-1,3-disulfohydrazide, etc. are used as the foaming agent. Sulfohydrazide compound, N, N'-dinitrosopentamethylenetetramine, N, N'-dinitroso-N,
Examples thereof include nitroso compounds such as N′-dimethyl terephthalamide, azide compounds such as terephthal azide and P-tert-butylbenzazide, and examples of inorganic compounds include ammonium carbonate and sodium bicarbonate.

The masking tape is preferably insoluble in the polymerization liquid and has water repellency.

If the width of the seal portion is too narrow, the invasion of the polymerization solution in the subsequent step cannot be prevented, and if it is too wide, the element size becomes large. Therefore, the width is 0.2 to 2 mm, preferably 0.5 to
1.5mm is good.

If the gap between the seal portions is too small, the final anode lead-out portion remaining after removing the masking tape in the subsequent step becomes small and the workability deteriorates.
25 mm, preferably 1.0 to 10 mm.

When electrolytic polymerization is carried out, in the present invention, the power supply terminal is brought into contact with the chemically oxidized polymer film formed on the masking tape.

[0030]

As described above, by forming at least two seal portions made of an adhesive resin in the anode lead-out portion and attaching the masking tape through the seal portions, the anode lead-out portion can be reliably masked. To be done.

Therefore, it is not necessary to manage the liquid surface during the chemical polymerization. Moreover, since the entire comb tooth-shaped protrusions are used as the element foil, a higher electrostatic capacitance can be obtained even though they have the same size. This means that the product size can be reduced.

Further, during the electrolytic polymerization, by bringing the power supply terminal into contact with the chemically-oxidized polymerized film formed on the masking tape, damage of the anodized film and the like is prevented, and short-circuit defects are greatly reduced.

Further, by forming the protrusions in the shape of comb teeth on both sides of the anode lead portion, not only the productivity is doubled, but also capacitor elements can be rationally stacked.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, aluminum etched foil (thickness 90
˜100 μm) was anodized at 33 V to form a dielectric oxide film on the surface.

Then, as shown in FIG. 1, a strip of the anode lead-out portion 11 having a predetermined width is left at a substantially central portion of the aluminum etched foil 10 by a mold or the like, and a capacitor element foil is provided on both sides thereof. Projections 1 used as
2 ..., 13 ... were punched out in a comb shape.

Next, the entire aluminum etched foil 10 was dipped in a chemical conversion solution and anodized again at 33 V to form a dielectric oxide film including the cut portion. In this embodiment, the size of each of the protrusions 12 and 13 is 3 mm in both the vertical dimension H and the horizontal dimension W.

Thereafter, as shown in FIGS. 2 and 3, an adhesive resin (silicon resin manufactured by Shin-Etsu Chemical Co., Ltd., curing temperature 1) was applied to both surfaces of the anode extraction portion 11 by screen printing.
(00 ° C.) along the lengthwise direction of the anode lead-out portion 11 with a width of 0.6 mm and an interval of 3 mm, and two seal portions 1 are applied.
4 and 14 were formed respectively.

Then, in order to mask the anode lead-out portion 11, a masking tape 15 made of polyethylene terephthalate and having a width of 5 mm is attached so as to straddle the seal portions 14 and 14 and heated at 100 ° C. for 10 minutes to seal the same. Part 14
Was cured.

After masking the anode lead-out portion 11 in this way, the entire aluminum etched foil 10 is dipped in a solution containing a conductive polymer monomer (pyrrole monomer), and the conductive high-pores are introduced into the pores. The molecular monomer was introduced. In this example, the weight ratio of pyrrole monomer: ethanol: water =
It was immersed for 5 minutes in a 3: 3: 1 solution.

Then, 0.3 mol / l of ammonium persulfate as an oxidizing agent and 0.1 mol / l of tetraethylammonium paratoluenesulfonic acid as a supporting electrolyte.
4) It is immersed in a solution containing P for 5 minutes to carry out chemical polymerization,
As shown in FIG. 5, a chemical oxidation polymerization film 16 was formed on each of the protrusions 12 and 13 and the masking tape 15.

When the adhered amount of the chemically oxidized polymer film 16 is small, the above process may be repeated several times. Oxidant,
Even if a supporting electrolyte other than those mentioned above is used, a chemically oxidized polymer film 16 made of a similar conductive polymer substance can be obtained. Further, after the chemical oxidation polymerization film 16 is formed in this way, the whole may be immersed in a chemical conversion solution for re-chemical conversion.

Thereafter, the entire aluminum etched foil 10 was immersed in an aqueous solution containing 0.2 mol / l of a pyrrole monomer as a conductive polymer monomer and 0.04 mol / l of an alkylnaphthalenesulfonic acid as a supporting electrolyte. As shown in FIG. 5, an electrolytic polymerization film 17 was formed on the chemically oxidized polymerization film 16.

That is, as shown in FIG. 6, the aluminum etched foil 10 is soaked in the electrolytic polymerization tank 18 so that the whole is immersed in the electrolytic polymerization solution, and the chemicals formed on the masking tape 15 are formed. The positive side power supply terminal 19 made of a stainless wire or the like is brought into contact with the oxidation polymerization film 16, while the electrolytic polymerization tank 18 side is set to the negative side.
Electrolytic polymerization was performed at a current density of 1 mA / square millimeter to form an electrolytic polymerized film 17 on the chemically oxidized polymerized film 16.
An electropolymerized film 17 made of the same conductive polymer substance can be obtained even if the conductive polymer monomer and the supporting electrolyte are other than those mentioned above.

Next, as shown in FIG. 7, the masking tape 15 was peeled off by a cutter or the like to expose the anode lead-out portion 11. The masking tape 15
In peeling, the portion directly attached to the seal portion 14 was left as it was.

By peeling off the masking tape 15 as described above, the chemically oxidized polymer film 16 and the electrolytic polymer film 17 are removed.
Was separated into a protrusion 12 side and a protrusion 13 side, and a carbon layer 20 and a silver layer 21 as a cathode extraction layer were baked on each electropolymerized film 17 thereof.

In this way, the capacitor elements C1 and C2 are formed on both sides of the anode lead-out portion 11 by the number of protrusions.

At this point, each capacitor element C1, C2
May be separated from the anode lead-out portion 11 with the required anode lead attached, but in this embodiment, by bending the anode lead-out portion 11 as shown in FIG. C1 and C2 were laminated, and the cathode terminal plate 22 of the lead frame was placed between the silver layers 21 and 21 and attached with a conductive adhesive.

The anode lead-out portion 11 was welded to the anode terminal plate 23 of the same lead frame. In this case, the anode lead-out portion 11 is provided with a welding margin 11a formed by cutting and raising a part thereof, and the anode margin 2a of the lead frame is provided on the welding margin 11a.
3 was welded.

In this embodiment, the cathode terminal plate 22 is inserted between the capacitor elements C1 and C2, but both elements C1 and C2 are laminated, and the cathode is provided on the outer surface side of either one of the silver layers 21. The terminal board 22 may be attached.

Then, a resin exterior body was formed around each of the capacitor elements C1 and C2 by a resin molding method and aged to obtain a solid electrolytic capacitor as a final product.

When this is set as Example 1, the yield is 9
6%, and assembly failure during lamination was 3%. By the way,
The yield of the conventional example described above was 71%, and assembly failure at the time of stacking reached 10%. The cause is the positional deviation when stacking the individually separated capacitor elements. Further, assuming that the production capacity of the conventional example is 100, the production capacity of the first embodiment shows a numerical value of 200.

In the first embodiment described above, the protrusions are provided on both sides of the anode lead-out portion 11 in a comb-like shape, but in the present invention, as shown in FIG. 9, the protrusion 1 is provided on one side of the anode lead-out portion 11.
It is also applicable to the case where 2 is formed in a comb shape.

In the case of Example 2, also in this case, the sealing portions 14 and 14 made of the adhesive resin are provided on both surfaces of the anode lead-out portion 11, and the masking tape 15 is provided so as to extend over the sealing portions 14 and 14. And the anode lead-out portion 11 is masked.

The other steps were the same as in Example 1 above, and the yield of Example 2 was 96%. For reference, Table 1 shows the results of comparison between Examples 1 and 2 and the conventional example.

[0055]

[Table 1] In Example 1, after forming the electrolytic polymerized film 17,
Although the masking tape 15 is peeled off, the masking tape 15 may be peeled off after the chemical oxidation polymerization film 16 is formed or after the carbon layer 20 and the silver layer 21 as the cathode extraction layer are formed on the electrolytic polymerization film 17.

However, when the masking tape 15 is peeled off after the chemically oxidized polymer film 16 is formed, electrolytic polymerization is carried out separately for the protrusions 12 and 13 on each side, and at that time, the power supply terminal 19 is also used. Is the chemically oxidized polymer film 1 on the masking tape 15 left on the seal portion 14.
6 will be contacted.

Further, although the example in which the two seal portions 14 are provided has been described, it should be understood that the number may be, for example, three, that is, any plurality of seal portions may be provided.

[0058]

As described above, according to the present invention,
At least two seal parts made of an adhesive resin are formed on the anode lead-out part, and a masking tape is attached through the seal parts so that the anode lead-out part can be reliably masked. Liquid level management at the time becomes unnecessary, and the product yield is greatly improved.

Moreover, since the entire comb-teeth-shaped protrusions are utilized as the element foil, a higher electrostatic capacitance can be obtained even with the same size.

In addition, since the power supply terminal is brought into contact with the chemically oxidized polymerized film formed on the masking tape during electrolytic polymerization, external force is not directly applied to the anodic oxide film and the like, and therefore short circuit occurs. There is an effect that it is possible to prevent the occurrence of defects.

[Brief description of drawings]

FIG. 1 relates to a first embodiment of the present invention, in which a dielectric oxide film is formed on a belt-shaped valve action metal foil which is pre-etched and has a predetermined width, and then a capacitor element foil is formed on both sides of an anode lead portion. FIG. 3 is a front view showing a state in which a plurality of projections used are formed in a comb shape.

FIG. 2 is a cross-sectional view showing a state in which a masking tape is attached to the anode extraction portion of FIG.

FIG. 3 is a perspective view showing a state in which a masking tape is attached to the anode extraction portion of FIG.

FIG. 4 is a cross-sectional view showing a state in which a chemically oxidized polymer film is formed.

FIG. 5 is a sectional view showing a state in which an electrolytically polymerized film is formed.

FIG. 6 is an explanatory view for explaining a process of forming an electrolytic polymerization film.

FIG. 7 is a cross-sectional view showing a state in which a masking tape is peeled off, a cathode extraction layer is formed, and capacitor elements are formed on both sides of an anode extraction part.

FIG. 8 is a side view showing a state in which each capacitor element is laminated by bending an anode lead portion.

FIG. 9 is an explanatory diagram for explaining a second embodiment of the present invention.

FIG. 10 is an explanatory diagram for explaining a conventional example.

FIG. 11 is an explanatory diagram illustrating a process of forming an electrolytically polymerized film in a conventional example.

[Explanation of symbols]

 10 Aluminum Etched Foil 11 Anode Extraction Part 12, 13 Projection Part 14 Seal Part 15 Masking Tape 16 Chemical Oxidation Polymerization Film 17 Electrolytic Polymerization Film 20 Carbon Layer 21 Silver Layer 22 Cathode Terminal Plate 23 Anode Terminal Plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Manabu Kanahara 2-2-1 Tsujido Shinmachi, Fujisawa City, Kanagawa Elner Co., Ltd.

Claims (6)

[Claims] 1. A dielectric oxide film is formed on a valve-action metal foil having a predetermined width, which has been etched in advance, and is used as a capacitor element foil on at least one side of the valve-action metal foil, leaving a strip-shaped anode lead-out portion. After arranging a plurality of protrusions in a comb-teeth shape, at least two seal portions made of an adhesive resin are applied to the anode lead-out portion along its length in a ridge-like shape at a predetermined interval. A masking tape is attached so as to cover the anode lead-out part through the same seal part, and then a chemically oxidized polymer film is formed by the chemical polymerization method, then immersed in an electrolytic polymerization solution and then the same chemically oxidized polymer film is formed by the electrolytic polymerization method. A method for producing a solid electrolytic capacitor, characterized in that an electrolytically polymerized film made of a conductive polymer substance is formed on the upper surface. 2. The masking tape is removed after the chemically oxidized polymer film is formed.
A method for manufacturing the solid electrolytic capacitor as described in. 3. The method for producing a solid electrolytic capacitor according to claim 1, wherein the masking tape is removed after forming the electrolytic polymerized film. 4. The method for producing a solid electrolytic capacitor according to claim 1, wherein the masking tape is removed after forming a carbon layer and a silver layer on the electrolytic polymerized film. 5. A plurality of pieces which are used as capacitor element foils on both sides of which a dielectric oxide film is formed on a valve-action metal foil having a predetermined width that has been etched in advance, and strip-shaped anode lead-out portions are left on the valve-action metal foil. After the protrusions are continuously formed in a comb shape, at least two seal portions made of an adhesive resin are applied in a ridge shape along the length direction of the anode lead portion at a predetermined interval, and the anode lead portion A masking tape is attached to cover the drawer through the seal, and then a chemically oxidized polymer film is formed by the chemical polymerization method, and then immersed in an electrolytic polymerization solution and then electropolymerized on the chemically oxidized polymer film. To form an electropolymerized film made of a conductive polymer substance, further forming a carbon layer and a silver layer as a cathode extraction layer on the electropolymerized film, any of the steps after the chemical oxidation polymerized film formation 2. The method for producing a solid electrolytic capacitor, wherein the masking tape is removed, and the capacitor elements formed on both sides of the anode lead-out portion are laminated by bending the anode lead-out portion. 6. The electrolytic polymerization is carried out by bringing the power supply terminal into contact with the chemical oxidation polymerization film formed on the masking tape during the electrolytic polymerization. Manufacturing method of solid electrolytic capacitor.