JPS63111609A - Manufacture of solid electrolytic capacitor - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a solid electrolytic capacitor that can easily produce a solid electrolytic capacitor with good performance.

[Conventional technology]

Conventionally, solid electrolytic capacitors are made by attaching a semiconductor to a valve metal such as aluminum having an anodized film.

[Problem that the invention seeks to solve]

However, the number of times the semiconductor is deposited is large, the manufacturing process becomes long, and the film tends to deteriorate.

In view of the above circumstances, it is an object of the present invention to provide a method for manufacturing a solid electrolytic capacitor that can reduce the number of times a semiconductor is deposited, simplify the manufacturing process, and further prevent deterioration of the film.

[Means for solving problems]

The present invention has been made to achieve the above object, and its gist consists of a wound element consisting of an anode foil and a cathode foil wound together via a separator, and a solid electrolyte consisting of a semiconductor impregnated into the element. The present invention provides a method for manufacturing a solid electrolytic capacitor in which the separator is impregnated with the semiconductor before being wound.

[Specific structure and operation of the invention]

Hereinafter, a method for manufacturing a solid electrolytic capacitor according to the present invention will be explained.

Valve metals such as aluminum, tantalum, niobium, and titanium are used for the anode foil and cathode foil used in the present invention, and a chemical conversion coating for pressure resistance is formed on the anode foil by a known method. An oxide film is also formed on the cathode foil to make it naturally oxidized or non-polar. Lead wires are connected to the anode foil and cathode foil by caulking, high frequency bonding, or the like before and after providing the film. Furthermore, the material of the separator used in the present invention is not particularly limited, and known separators such as paper and nonwoven fabric can be used. There are no particular restrictions on the composition or manufacturing method of the semiconductor impregnated into the separator and the semiconductor impregnated into the wound element consisting of the anode foil and cathode foil wound through the separator, but lead dioxide is required to improve the performance of the capacitor. Alternatively, it is preferable to use lead dioxide and lead sulfate as main components and produce it by a known chemical precipitation method or electrochemical precipitation method.

Examples of the chemical precipitation method include a method of chemically precipitating from a reaction mother liquor containing a lead-containing compound and an oxidizing agent.

Examples of lead-containing compounds include oxine, acetylacetone, pyromeconic acid, salicylic acid, alizarin, polyvinyl acetate, and porphyrin compounds.

Lead-containing compounds in which a lead atom has a coordinate bond or ionic bond to a chelate-forming compound such as a crown compound or a cributate compound, lead citrate, lead acetate, basic lead acetate,
Lead chloride, lead bromide, lead perchlorate.

Lead chlorate, lead sulfimate, lead hexafluorosilicate, lead bromate, lead borofluoride, lead acetate hydrate.

Examples include lead nitrate. These lead-containing compounds are appropriately selected depending on the solvent used for the reaction mother liquor, and water or an organic solvent is used as the solvent.

Further, two or more kinds of lead-containing compounds may be used in combination.

The concentration of lead-containing compounds in the reaction mother liquor is 0.05 mol/J
to a concentration that provides saturated solubility, preferably from 0.1 mol/J to a concentration that provides saturated solubility, and more preferably from 0.5 mol/J to a concentration that provides saturated solubility. It is within the range of up to the concentration. If the concentration of the lead-containing compound in the reaction mother liquor is less than 0.05 mol/J, a solid electrolytic capacitor with good performance cannot be obtained. Further, if the concentration of the lead-containing compound in the reaction mother liquor exceeds the saturation solubility, no merit can be observed by adding an increased amount.

Examples of oxidizing agents include quinone and chloranil.

Pyridine-N-oxide, dimethyl sulfoxide, chromic acid, potassium permanganate, selenium oxide, mercury acetate, vanadium oxide, sodium chlorate, calcium perchlorate, calcium chlorate, calcium hypochlorite 1. Examples include calcium chlorite, ferric chloride, hydrogen peroxide, mustard powder, and benzoyl peroxide. These oxidizing agents may be appropriately selected depending on the solvent used for the reaction mother liquor, and two or more oxidizing agents may be used in combination.
5 - May be.

The amount of oxidizing agent used is 0.1 of the molar amount of lead-containing compound used.
It is preferably within the range of ~5 times the mole. If the ratio of the oxidizing agent used exceeds 5 times the molar amount of the lead compound used, there is no cost advantage, and if it is less than 0 or 1 times the molar amount, a solid N-solution capacitor with good performance cannot be obtained. .

As a method for forming a semiconductor layer containing lead dioxide as a main component, for example, a reaction mother liquor is prepared by mixing a solution containing a lead-containing compound and a solution containing an oxidizing agent, and then the reaction mother liquor is coated with a separator or wrapped. An example is a method of chemically depositing the element by immersing it.

- On the other hand, examples of electrochemical deposition methods include the method previously proposed by the present inventors in which lead dioxide is deposited by electrolytic oxidation in an electrolytic solution containing a high concentration of lead-containing compounds (particularly Gansho 6l-26952).

In addition, since semiconductors are composed of semiconductors whose main components are lead dioxide, which plays the role of a semiconductor, and lead sulfate, which is an insulator, the leakage current value of a capacitor can be reduced by adding lead sulfate. can. On the other hand, the electrical conductivity of the semiconductor layer decreases due to the addition of lead sulfate, which increases the loss factor value, but the present invention maintains a high level of performance compared to conventional solid electrolytic capacitors. discovered.

Therefore, when the semiconductor is composed of a mixture of lead dioxide and lead sulfate, good capacitor performance can be maintained over a wide range of compositions in which the lead dioxide is 10 parts by weight or more and less than 100 parts by weight and the lead sulfate is 90 parts by weight or less. 1 can be expressed.

Especially 80 parts by weight of lead sulfate to 20 to 50 parts by weight of lead dioxide
~50 parts by weight, and moreover, a good balance between the leakage current value and the loss factor value is achieved in the range of 75 to 65 parts by weight of lead sulfate to 25 to 35 parts by weight of lead dioxide. If the amount of lead dioxide is less than 10 parts by weight, conductivity will be poor, resulting in a large loss factor and insufficient capacity.

A semiconductor containing lead dioxide and lead sulfate as main components can be formed by chemical precipitation using, for example, an aqueous solution containing lead ions and persulfate ions as a reaction mother liquor. Additionally, a suitable oxidizing agent that does not contain persulfate ions may be added.

The lead ion concentration in the mother liquor is 0.05 mol/J from the concentration that gives saturated solubility, preferably 0.1 mol/J from the concentration that gives saturated solubility, more preferably 2! It is within the range of 0.5 mol/j from Maro. Lead ion 1! If the solubility of malt is higher than the saturation solubility, there is no benefit from adding an increased amount.

Further, when the concentration of lead ions is lower than 0.05 mol/j, there is a problem that the number of applications must be increased because the lead ions in the mother liquor are too thin.

On the other hand, the concentration of persulfate ions in the mother liquor is within the range of 5 to 0.05 in molar ratio to lead ions.

If the concentration of persulfate ions is more than 5 in molar ratio to lead ions, unreacted persulfate ions remain, resulting in a high cost i, and the concentration of persulfate ions is 0 in molar ratio to lead ions. If it is less than .05, unreacted lead ions remain and conductivity deteriorates, which is not preferable.

Typical examples of compounds that provide lead ion species include lead citrate, lead perchlorate, lead nitrate, lead acetate, basic lead acetate, lead chlorate, lead sulfamate, lead silicon hexafluoride, lead bromate, and chloride. Examples include lead and lead bromide. Two or more of these compounds providing lead ion species may be used in combination.

On the other hand, examples of compounds that provide persulfate ion species include potassium persulfate, sodium persulfate, ammonium persulfate, and the like. Two or more of these compounds that provide persulfate ion species may be used in combination.

On the other hand, examples of oxidizing agents include hydrogen peroxide.

Examples include calcium hypochlorite, calcium chlorite, calcium chlorate, calcium perchlorate, and the like.

A solid electrolytic capacitor manufactured by the method of the present invention configured as described above is, for example, a resin mold.

A general-purpose solid electrolytic capacitor product for various uses can be made by using a resin case, a metal outer case, resin dipping, and lamination 1 with a film exterior.

〔Example〕

Hereinafter, the method of the present invention will be explained in more detail by showing Examples and Comparative Examples.

Example 1 Non-woven paper with a thickness of about 70 μm was treated with 2.4 mol/lead acetate trihydrate.
The sample was immersed in a mixed solution (reaction mother liquor) of an aqueous solution of J and an aqueous solution of 4 mol/J of ammonium persulfate, reacted at 80° C. for 30 minutes, washed with water, and then dried. After repeating this operation five times, a piece of a predetermined length was cut out from the semiconductor-treated nonwoven paper and used as a separator.

Subsequently, a wound element was produced using an anode foil, a cathode foil, and the above separator. Further, the wound element was immersed in a reaction mother liquor of the same type and concentration as the above reaction mother liquor, reacted at 80° C. for 30 minutes, and then dried. This operation was repeated twice. The wound element impregnated with the fabricated semiconductor was housed in an aluminum can and sealed with resin to fabricate a solid electrolytic capacitor. In addition, the semiconductor in the separator and the semiconductor in the wound element are
It was confirmed by X-ray analysis and infrared spectroscopy that it consisted of about 25% by weight of lead dioxide and about 75% by weight of lead sulfate.

Example 2 A 25 μm thick flat foil material containing rayon as the main component was added to the same reaction mother liquor as in Example 1, and hydrogen peroxide solution (0.0%,
After semiconductor processing was carried out in the same manner as in Example 1 except that 0.5 mol/J was added, a separator was cut out. Further, a wound element was produced in the same manner as in Example 1, and then impregnated with a semiconductor by treatment with a solution similar to that used to produce the separator of this embodiment. A solid electrolytic capacitor was then produced in the same manner as in Example 1. Furthermore, it was confirmed that the semiconductor in the separator and the semiconductor in the wound element were composed of lead dioxide and lead sulfate, and that lead dioxide contained approximately 50% by weight.

Example 3 A nylon flat foil fiber having a thickness of 50 μm was immersed in a 1.0 mol/j aqueous solution of lead acetate trihydrate, and a diluted aqueous solution of 0.5 times the mol of hydrogen peroxide was added thereto. After being left for 1 hour, it was washed with water and dried. After repeating this operation twice to process the semiconductor, a piece of a predetermined length was cut out and used as a separator. Subsequently, a wound element was made in the same manner as in Example 1, and then impregnated with a semiconductor by treatment with the same solution as that used to prepare the separator of this example. A solid electrolytic capacitor was then produced in the same manner as in Example 1. It was also confirmed that the semiconductor in the separator and the semiconductor in the wound element were made of lead dioxide.

Comparative Example 1 A solid electrolytic capacitor was produced in the same manner as in Example 2, except that no semiconductor treatment was performed and an IC separator was used.

Table 1 shows the characteristic values of the solid electrolytic capacitors manufactured in Examples 1 to 3 and Comparative Example 1.

Table 1 However, * indicates the measured value at 120H2. As is clear from Table 1, solid electrolytic capacitors using semiconductor-treated separators require fewer times of impregnating the wound element with semiconductor, and the manufacturing process is simple. It is. Furthermore, since the performance is good, it has high industrial utility value.

〔Effect of the invention〕

In the solid electrolytic sensor manufactured by the method of the present invention, since the semiconductor is already attached to the separator, the number of times the element is impregnated with the semiconductor can be reduced, and the manufacturing process can be simplified. Furthermore, the deterioration of the oxide film can be reduced, and the value of industrial use is extremely high.

Claims (3)

[Claims] (1) In a solid electrolytic capacitor consisting of a wound element consisting of an anode foil and a cathode foil wound together through a separator, and a semiconductor impregnated into the element, the separator is impregnated with the semiconductor before being wound. A method for manufacturing a solid electrolytic capacitor, characterized in that a solid electrolytic capacitor is manufactured using a solid electrolytic capacitor. (2) The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein the semiconductor layer is a semiconductor containing lead dioxide as a main component. (3) The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein the semiconductor layer is a semiconductor whose main components are lead dioxide and lead sulfate.