JP2918590B2 - Method for manufacturing solid electrolytic capacitor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolytic capacitor using a conductive polymer, polypyrrole, as a solid electrolyte, and more particularly, to a process for chemically polymerizing pyrrole on a chemical conversion foil. And a method of manufacturing a solid electrolytic capacitor for facilitating and ensuring chemical polymerization.

2. Description of the Related Art Electrolytic capacitors are small, large-capacity, inexpensive, and have excellent characteristics such as smoothing of rectified output, and are one of important components of various electric and electronic devices. In general, electrolytic capacitors are classified into an electrolytic solution type and a solid type. A conductive oxide or organic substance such as polypyrrole is interposed as a solid electrolyte. Since the electrolytic solution type electrolytic capacitor is based on ionic conduction using a liquid electrolyte, the resistance significantly increases and the impedance increases in a high frequency region. Therefore, in terms of high-frequency characteristics, solid electrolytic capacitors are much better.

As the solid electrolyte used for the solid electrolytic capacitor, the conductivity and stability of the solid electrolyte itself, and the capacitance (Cap), dielectric loss tangent (tanδ), and leakage current (LC ) And the equivalent series resistance (ESR), polypyrrole is considered to be the best.

A solid electrolytic capacitor using polypyrrole as a solid electrolyte is described in, for example, JP-A-63-174223. Generally, when manufacturing this type of solid electrolytic capacitor, a thin film of polypyrrole is formed on the anode foil by chemical polymerization and electrolytic polymerization, and then the terminals are bonded to this surface using a conductive paste such as silver paste. Take out the counter electrode lead and cover it with epoxy resin or the like to make a capacitor product.

On the other hand, with the progress of miniaturization of electric and electronic devices in recent years,
Electrolytic capacitors are being miniaturized, and demands for so-called chip capacitors and the like are increasing. In manufacturing this type of electrolytic capacitor, a manufacturing method of simultaneously manufacturing a large number of small-sized chip materials having a certain quality is adopted.

For example, when manufacturing a flat solid chip, when forming a polypyrrole polymer film on a flat aluminum chemical conversion foil, placing an auxiliary member such as a resist having a grid of a predetermined size on the chemical conversion foil, By handling the squares exposing the chemical conversion surface as a unit, forming a polypyrrole film by polymerization, and separating into chips for each square, a large number of small-dimension chipping materials with a certain quality are manufactured at the same time. You. When a polypyrrole polymer film is formed on a flat chemical conversion foil by such a method, the polymer film is ideally formed only on the squares, so that the post-process such as a cleaning operation can be simplified, and further, mechanization and mass production It is desirable to adopt a manufacturing process that can be easily performed.

When manufacturing wound solid chip capacitors,
At present, its size is reduced to only a few millimeters, so the structure itself of the element wound with a flat aluminum conversion foil is basically the same as that of the conventional one, but various manufacturing processes Inconvenience has occurred. For example, in the conventional pyrrole-forming reaction, an oxidizing agent was mixed with a pyrrole solution, or an oxidizing agent was applied to an electrode and immersed in a pyrrole solution. In the case of manufacturing a capacitor, rationalization is relatively difficult, and the excess pyrrole solution after the impregnation of the solution into the capacitor element is discarded due to the progress of the oxidation reaction, which is wasteful and increases the cost. In addition, when the wound element is extremely small, reliable impregnation becomes more difficult, and when impregnation is performed one by one, handling becomes difficult,
This was a factor that hindered the rationalization of the mechanization and mass production processes.

[Problems to be Solved by the Invention] The present invention, when producing a solid electrolytic capacitor using a conductive polymer polypyrrole as a solid electrolyte, by improving the use of pyrrole and oxidizing agent in the chemical polymerization step, These are effectively supplied to the required locations in the required amount to facilitate and ensure chemical polymerization.
Accordingly, it is intended to provide a manufacturing method of a solid electrolytic capacitor which aims to produce a flat solid chip having a good impregnation rate, to produce a wound solid chip capacitor which is easy to produce, and to further improve the efficiency of the whole production process. Aim.

[Means for Solving the Problems] According to the present invention, a solid electrolytic capacitor having a polypyrrole film formed by performing chemical polymerization of pyrrole on a conversion foil having an oxide film on its surface as a solid electrolyte is manufactured. In this case, a pyrrole solution and an oxidizing agent solution were separately prepared, and a certain amount of a separately prepared pyrrole solution and an oxidizing agent solution were alternately dropped on a chemically converted foil portion to be subjected to chemical polymerization, and a polypyrrole film was formed by chemical polymerization. The method for producing a solid electrolytic capacitor is characterized in that it is commercialized after the formation of a solid electrolytic capacitor.

Furthermore, according to the present invention, when manufacturing a solid electrolytic capacitor using a polypyrrole film formed by performing chemical polymerization of pyrrole on a conversion foil having an oxide film on its surface as a solid electrolyte, a mass having a predetermined size is used. It consists of forming a chemically polymerized film of pyrrole on the squares exposing the chemical conversion part of the aluminum conversion foil or conversion plate on which the resist is printed in the form of eyes, separately preparing a pyrrole solution and an oxidizing agent solution, A constant amount of separately prepared pyrrole solution and oxidizing agent solution are alternately dropped onto the chemical conversion foil part to be subjected to polymerization, and a polypyrrole film is formed by chemical polymerization. A method for manufacturing a solid electrolytic capacitor is provided.

Furthermore, according to the present invention, when manufacturing a solid electrolytic capacitor having a polypyrrole film formed by performing chemical polymerization of pyrrole on a conversion foil having an oxide film on the surface, a pyrrole solution and an oxidizing agent solution And a fixed amount of a separately prepared pyrrole solution and an oxidizing agent solution are alternately dropped onto the winding end surface of the winding element fixed to the support, and after impregnating with polypyrrole, molding is performed as it is. And a method for manufacturing a solid electrolytic capacitor characterized in that it is made into a chip by means of a chip.

A chemical conversion foil having an oxide film on its surface is usually an aluminum film whose surface has been changed to an oxide film dielectric by electrolytic oxidation.

Preferably, the pyrrole solution is an ethanol solution containing 10 to 30% by weight of pyrrole.

It is preferred that the oxidizing agent for chemical polymerization is selected from the group consisting of (NH ₄ ) ₂ S ₂ O ₈ , FeCl ₃ , and H ₂ O ₂ .

Preferably the oxidizing agent solution, 10-30 fold uppermost% of (NH _{4) 2} S
An aqueous solution containing ₂ O ₈ is used.

In the case of manufacturing a flat solid chip, the size of the resist square is preferably about 1 mm × 1 mm to 5 mm × 5 mm. The resist can be made of a material such as a phenolic resin or an epoxy resin for screen printing. A pyrrole solution is applied to the squares of this resist.
It was added dropwise at a dropping amount of 10~30μl / cm ^2, an oxidizing agent solution 10-30
The solution is dropped at a drop volume of μl / cm ² . The pyrrole solution and the oxidizing agent solution are preferably dropped alternately, preferably 2 to 10 times.

After a polypyrrole polymer film is formed on a flat chemical conversion foil by the above-described method, it is made into a device by a conventional method, sealed, and commercialized.

When manufacturing a wound solid chip capacitor, the support may be a lead frame, and the wound element is preferably a frame-welded wound element. The amount of the pyrrole solution and the oxidizing agent solution to be dropped can vary depending on the size of the wound element and the like, but is preferably an amount that allows the entire element to be impregnated by one drop. The pyrrole solution and the oxidizing agent solution are preferably dropped alternately, preferably 2 to 10 times.

It is preferable that a separator such as manila paper is interposed between the anode foil and the cathode foil of the wound element, because the impregnation becomes more reliable.

After a polypyrrole polymer film is formed in a wound solid chip capacitor by the above-described method, it is packaged and sealed by a conventional method to produce a product.

[Operation] As described above, when a flat solid chip is manufactured by a conventional method, an auxiliary member such as a resist having a grid of a predetermined size is placed on a chemical conversion foil to expose a chemical conversion surface. By handling the grids as a unit, a large number of small-sized chip materials having a certain quality can be manufactured at the same time, but ideally a polymer film is formed only on the grids and after a cleaning operation, etc. It has been expected that a manufacturing process that can simplify the process and that can be easily mechanized and mass-produced is realized.
Further, when manufacturing a wound type solid chip capacitor, particularly when manufacturing a small chip capacitor, rationalization is relatively difficult, and furthermore, the excess pyrrole solution after the solution impregnation of the capacitor element proceeds with an oxidation reaction. Therefore, it is discarded, wasteful and cost rises, and if impregnated one by one, it is difficult to handle and impedes the rationalization of the mechanization / mass production process.

The present invention improves the method of using pyrrole and the oxidizing agent in the chemical polymerization step, and effectively supplies them to the necessary and necessary parts, thereby facilitating and ensuring the chemical polymerization. is there.

That is, a pyrrole solution and an oxidizing agent solution are separately prepared, and a fixed amount of a separately prepared pyrrole solution and an oxidizing agent solution are alternately dropped onto the chemical conversion foil portion to be subjected to chemical polymerization, and the polypyrrole film is subjected to chemical polymerization. By forming the product after the formation, the pyrrole solution and the oxidizing agent solution can be used in required portions in required amounts, and the production process can be further rationalized.

[Effects of the Invention] According to the present invention, when manufacturing a solid electrolytic capacitor using polypyrrole, which is a conductive polymer, as a solid electrolyte, the method of using pyrrole and the oxidizing agent in the chemical polymerization step is improved, and A winding type solid chip capacitor that effectively supplies the required amount to the required location, facilitates and ensures chemical polymerization, thereby producing a flat solid chip with good impregnation rate and easy to manufacture. The present invention provides a method for manufacturing a solid electrolytic capacitor which is intended to manufacture a solid electrolytic capacitor and further improves the efficiency of the entire manufacturing process.

EXAMPLES The present invention will be described in more detail with reference to the accompanying drawings by way of examples below, but the present invention is not limited to only the following examples.

FIG. 1 is an explanatory view showing an operation of dropping a pyrrole solution and an oxidant solution on a chemical plate provided with a printed resist, and FIG. 2 is an operation of dropping a pyrrole solution and an oxidant solution on a wound element fixed to a lead frame. FIG.

In FIG. 1, reference numeral 10 denotes an aluminum plate, 12 is a square, 14 is a resist, 16 is a dropping device, and 18 is a droplet. In FIG. 2, reference numeral 20 denotes a winding element, 22 denotes a lead frame, 24 denotes a winding end face of the winding element, 26 denotes a dropping device, and 28 denotes a droplet.

Example 1 As shown in FIG. 1, an aluminum conversion plate 10 was used.
A resist 14 having a square 12 of 3 mm × 3 mm was applied.

2 μl of a droplet 18 of an ethanol solution containing 20% by weight of pyrrole was dropped by the dropping device 16. Thereafter, 3 μl of a droplet 18 of an aqueous solution containing 30% by weight of (NH ₄ ) ₂ S ₂ O ₈ was dropped by the dropping device 16. Thereafter, washing and drying were performed. The operation from dropping of the pyrrole solution and the oxidizing agent solution to washing and drying was repeated twice.

Then, 5% dissolved in a 0.1 M / l BST / AN solution (BST: borodisalicylic acid triethylamine salt or triethylammonium borodisalicylate, AN: acetonitrile)
Using a pyrrole solution as an electrolytic solution, electrolytic polymerization was performed at ² mA / cm ² for 60 minutes.

After the completion of the electrolytic polymerization, a conductive paste was printed, and after cutting, electrodes were formed into chips to produce a solid electrolytic capacitor.

Comparative Example 1 The procedure of Example 1 was repeated except that the step of impregnating a 10% (NH ₄ ) ₂ S ₂ O ₈ aqueous solution into the square and placing it in pyrrole vapor at room temperature for 10 minutes to perform chemical polymerization was repeated twice. Similarly, a solid electrolytic capacitor was manufactured.

Table 1 shows the results of measuring the capacitance (Cap), the dielectric loss tangent (tan δ), the leakage current (LC), and the equivalent series resistance (ESR) of the solid electrolytic capacitors of Example 1 and Comparative Example 1. The rating was 6.3 WV (22 V _f ). The impregnation rates in Example 1 and Comparative Example 1 were 94% and 74%, respectively . Table 1 CaP (μF) tanδ LC (μA) ESR (100 KHz, Ω) Example 12.03 0.020 0.03 0.29 Comparative Example 11.60 0.021 0.02 0.35 Comparing the solid electrolytic capacitor according to the present invention shown in Example 1 with the solid electrolytic capacitor shown in Comparative Example 1,
Although the product characteristics shown in Table 1 are comparable when comprehensively evaluated, it can be seen that in the case of the present invention, the impregnation rate was greatly improved.

Example 2 As shown in FIG. 2, an anode foil having a width of 2.2 mm × 10 mm (22 _Vf ) and a cathode foil having a width of 2.2 mm × 13 mm were used. A winding element 20 having been carbonized at 350 ° C. for 2 minutes was used, fixed to a lead frame 22, and a pyrrole solution and an oxidizing agent solution were dropped onto a winding end face 24 of the winding element.

At the time of dropping, first, 20% by weight was dropped by the dropping device 26.
3 μl droplets of an ethanol solution containing
Was added dropwise. Thereafter, 6 μl of a droplet 28 of an aqueous solution containing 30% by weight of (NH ₄ ) ₂ S ₂ O ₈ was further dropped by the dropping device 26. Thereafter, washing and drying were performed. 10 operations from dripping of pyrrole solution and oxidizing agent solution to washing and drying
Repeated times.

Then, it was molded into chips to produce a product, and a solid electrolytic capacitor was manufactured.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an operation of dropping a pyrrole solution and an oxidizing agent solution on a chemical conversion plate provided with a printed resist.
The figure is an explanatory view showing an operation of dropping a pyrrole solution and an oxidant solution on a winding element fixed to a lead frame. 10 ... aluminum plate, 12 ... square 14 ... resist, 16 ... dripping device 18 ... droplet, 20 ... winding element 22 ... lead frame 24 ... winding end face of winding element 26 ... … Drip device, 28… Drop

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Susumu Ando 1-167, Higashi-oume, Ome-shi, Tokyo, Japan Nippon Chemi-Con Corporation (56) References JP-A-63-173313 (JP, A) JP-A-64 -82516 (JP, A) JP-A-1-268111 (JP, A) JP-A-3-198316 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01G 9/028

Claims (3)

(57) [Claims] In producing a solid electrolytic capacitor using a polypyrrole film formed by performing chemical polymerization of pyrrole on a conversion foil having an oxide film on its surface as a solid electrolyte, a pyrrole solution and an oxidizing agent solution are mixed. Prepared separately,
A solid electrolytic method characterized in that a fixed amount of a pyrrole solution and an oxidizing agent solution separately prepared are alternately dropped onto a chemical conversion foil portion to be subjected to chemical polymerization, and a polypyrrole film is formed by chemical polymerization to produce a solid electrolyte. Manufacturing method of capacitor. 2. A method for producing a solid electrolytic capacitor using a polypyrrole film formed by chemical polymerization of pyrrole on a chemical conversion foil having an oxide film on its surface as a solid electrolyte, comprising a grid having a predetermined size. Consists of forming a chemically polymerized film of pyrrole on the squares exposing the chemical conversion part of the aluminum chemical conversion foil or chemical conversion plate on which the resist is printed, separately preparing a pyrrole solution and an oxidizing agent solution, A constant amount of separately prepared pyrrole solution and oxidizing agent solution are alternately dropped onto the chemical conversion foil portion to be provided, and a polypyrrole film is formed by chemical polymerization. Of manufacturing a solid electrolytic capacitor. 3. A method for producing a solid electrolytic capacitor using a polypyrrole film formed by chemically polymerizing pyrrole on a conversion foil having an oxide film on its surface as a solid electrolyte, wherein a pyrrole solution and an oxidizing agent solution are mixed. Prepared separately,
A fixed amount of a separately prepared pyrrole solution and an oxidizing agent solution are alternately dropped onto the winding end surface of the winding element fixed to the support, and after impregnation with polypyrrole, molded as it is into a chip to produce a product. A method for manufacturing a solid electrolytic capacitor, comprising: