JP2004235408A - Process for producing capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for producing a capacitor capable of realizing a large capacity and a low ESR with a size equivalent to that of a conventional capacitor. <P>SOLUTION: An electrode sheet 15 is formed by laminating an aluminium foil 12 to the opposite sides of a dielectric film 11, and a dielectric oxide film 18 is formed by etching and chemically converting the surface of the aluminium foil 12 in the electrode sheet 15. The dielectric oxide film 18 is cut with specified dimensions and each dielectric oxide film 18 is bonded with anode and cathode leads 20 and 21. Finally, it is wound along with a separator 24 thus forming a capacitor element 25. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a capacitor used for various electronic devices.
[0002]
[Prior art]
A conventional electrolytic capacitor is wound between two aluminum foils via a separator to form a capacitor element to which an external lead-out terminal is connected. This capacitor element is impregnated with a driving electrolytic solution and has a cylindrical shape with a bottom. And the open end of the metal case was sealed with a sealing material.
[0003]
In recent years, as digitalization of electric devices has progressed, high-frequency noise has increased in circuits, and high-frequency capacitors that absorb high-frequency noise have been desired.
[0004]
Conventional measures against high frequency include low-frequency and high-frequency electrolytic capacitors with a large capacitance value that absorb low frequencies, and film capacitors or ceramic capacitors with low ESR at high frequencies connected in parallel to separate capacitors with different characteristics. Absorbed noise.
[0005]
However, in the case of the above configuration, since different capacitors having different characteristics are used, there is a problem that a mounting area is large, miniaturization of the device is difficult, and production cost is increased.
[0006]
For example, Patent Document 1 discloses a configuration in which a dielectric film is interposed on the other surface on the anode side of a capacitor element to face the cathode side electrode with respect to this problem. Document 2 discloses a composite capacitor in which a separator and a dielectric film having a roughened surface are wound between bipolar electrode foils.
[0007]
[Patent Document 1]
Microfilm of Japanese Utility Model Application No. 57-31595 (Japanese Utility Model Application Publication No. 58-135932) [Patent Document 2]
JP-A-4-284615
[Problems to be solved by the invention]
However, the composite type capacitor as described above is one in which a capacitor element is configured with a dielectric film interposed therebetween, and instead of a separator having a function of preventing contact with burrs between aluminum foil and the other separator, a dielectric material is used. Since a film is used, the thickness of the dielectric film must be substantially equal to that of the separator, and a dielectric film having a thickness of 40 to 50 μm is required. For this reason, there is a problem that the size must be four times or more in order to obtain the same capacity as the conventional one.
[0009]
Also, simply winding the dielectric film between the electrode foils or between the electrode foil and the separator and the electrode foil, the contact area between the dielectric film and the electrode foil is insufficient, There has been a problem that the characteristics of the film have not been fully derived.
[0010]
An object of the present invention is to solve the problems of the related art and to provide a method of manufacturing a capacitor having the same size as that of the related art and realizing a large capacity and low ESR.
[0011]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention comprises a step of laminating an aluminum foil on both surfaces of a dielectric film to form an electrode sheet, and etching the surface of the aluminum foil of the electrode sheet by etching. Roughening the surface of at least one of the aluminum foils to form a dielectric oxide film by a chemical conversion treatment, and cutting the electrode sheet having the dielectric oxide film formed thereon into prescribed dimensions, Connecting the extraction leads of the anode and the cathode and winding them together with the separator to form a capacitor element; storing the capacitor element together with the driving electrolyte in a bottomed cylindrical metal case and sealing the open end of the metal case Sealing with a material.
[0012]
Further, the invention according to claim 2 of the present invention provides a step of arranging and laminating an aluminum foil having a dielectric oxide film formed on at least one side on both sides of a dielectric film to form an electrode sheet; A process of cutting into specified dimensions, connecting the anode and cathode lead wires to each aluminum foil, winding it together with the separator to form a capacitor element, and putting this capacitor element together with the driving electrolyte into a bottomed cylindrical metal case Storing and sealing the open end of the metal case with a sealing material.
[0013]
According to the above manufacturing method, the aluminum foil can be securely adhered to the dielectric film, so that a capacitor can be obtained which can simultaneously achieve a large capacity by the dielectric oxide film and a low ESR by the dielectric film. It has the action of:
[0014]
In addition, since a dielectric film is laminated with an aluminum foil and then cut into a prescribed size, a thin dielectric film can be used, so that a capacitor element having the same size as the conventional one can be obtained.
[0015]
Further, even if the surface of the dielectric film is not roughened, the capacitor element can be easily formed without idling of the winding shaft or deviation of winding.
[0016]
According to a third aspect of the present invention, in the step of forming an electrode sheet, the dielectric film is semi-melted by heating from the surface of the aluminum foil and laminated.
[0017]
In the invention described in claim 4, the step of forming the electrode sheet particularly includes the step of bonding the laminate using an insulating adhesive.
[0018]
According to the third and fourth aspects of the present invention, an electrode sheet having improved adhesion between the dielectric film and the aluminum foil can be obtained.
[0019]
According to a fifth aspect of the present invention, in particular, the step of connecting the lead of the anode and the cathode to the aluminum foil and winding the same together with the separator to form a capacitor element comprises forming an insulating portion around the connection of the lead of the anode and the cathode. By forming an insulating portion around each of the lead-out leads, it is possible to prevent the aluminum foil from being perforated or torn due to burrs on the lead-out lead portion.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
(Embodiment 1)
Hereinafter, the first and third aspects of the present invention will be described with reference to the first embodiment.
[0021]
FIG. 1 to FIG. 3 are diagrams illustrating a process of manufacturing an electrode sheet which is a main part of the capacitor according to the embodiment of the present invention.
[0022]
First, as shown in FIG. 1, aluminum foils 12 are arranged on both surfaces of a dielectric film 11 and laminated by a laminating roller 13. Subsequently, heat is applied to the aluminum foil 12 by the heating roller 14 to bring the dielectric film 11 into a semi-molten state, and the aluminum foil 12 is thermally welded to both surfaces of the dielectric film 11 to form an electrode sheet 15.
[0023]
Next, the aluminum foil 12 provided on both surfaces of the dielectric film 11 is immersed in the etching layer 16 to roughen the outer surface of the aluminum foil 12. Further, it is immersed in the chemical conversion layer 17 to form a dielectric oxide film 18 (not shown in this figure) on the surface of the roughened aluminum foil 12.
[0024]
Next, as shown in FIG. 2A, the electrode sheet 15 provided with the dielectric oxide film 18 is cut into a predetermined size by a slitter or the like to form an element sheet 19. Further, as shown in FIG. 2B, an anode lead 20 is electrically connected to one surface of the dielectric oxide film 18 of the element sheet 19 and a cathode lead 21 is electrically connected to the other surface. .
[0025]
In FIG. 2B, as shown in FIG. 3A, the element sheet 19 to which the lead leads 20 and 21 are attached is separated from the dielectric oxide film 18 on the anode lead lead 20 side into the separator 22 and the cathode foil 23. Then, the capacitor element 25 as shown in FIG.
[0026]
Finally, the capacitor element 25 is housed in a bottomed cylindrical metal case together with the driving electrolyte by a commonly used method, and the open end of the metal case is sealed with a sealing material to manufacture a capacitor. Things.
[0027]
In the capacitor manufactured by the above-described method, since the dielectric film 11 and the aluminum foil 12 are in close contact with each other, variations in capacitance are reduced, and the contact area between the dielectric film 11 and the aluminum foil 12 is increased. Capacitor extraction can be improved as compared with the above-mentioned capacitor.
[0028]
If the dielectric film 11 used in the above-described manufacturing method is made of polystyrene, polyester, polycarbonate, or the like, the capacitor can sufficiently exhibit high-capacity, low-ESR characteristics.
[0029]
Further, when the thickness of the dielectric film 11 is 1 to 10 μm, poor contact can be reduced even if burrs of the aluminum foil 12 occur.
[0030]
(Embodiment 2)
Hereinafter, the second embodiment of the present invention will be described with reference to a second embodiment.
[0031]
In the first embodiment, the dielectric oxide film 18 is formed after the electrode sheet is formed. In the present embodiment, the dielectric film 11 is formed on both sides of the dielectric film 11 with the aluminum foil and the dielectric film. A capacitor was manufactured by the same method as that of the first embodiment except that an aluminum foil having no oxide film was arranged.
[0032]
By using an aluminum foil on which a dielectric oxide film is formed, a capacitor manufactured by such a method can easily form an electrode sheet for obtaining an arbitrary capacitance, so that various types of capacitors can be obtained. be able to.
[0033]
(Embodiment 3)
Hereinafter, the third embodiment of the present invention will be described with reference to a third embodiment.
[0034]
In the first and second embodiments, the step of forming the electrode sheet is performed by laminating the aluminum foil 12 on the dielectric film 11. In the present embodiment, an insulating adhesive is applied to both surfaces of the dielectric film 11. The difference was that the coating was performed, and other than that, a capacitor was manufactured in the same manner as in the first embodiment.
[0035]
As described above, when the electrode sheet is formed as in the third embodiment, the electrode sheet can be easily bonded only by the pressure from the laminating roller 13 with an insulating adhesive or the like.
[0036]
Further, since the dielectric film 11 and the aluminum foil 12 are in close contact with each other, variations in capacitance are reduced, and the contact area between the dielectric film 11 and the aluminum foil 12 is increased. Can be improved.
[0037]
(Embodiment 4)
Hereinafter, the fourth embodiment of the present invention will be described with reference to the fourth embodiment.
[0038]
Although the anode lead 20 and the cathode lead 21 are electrically connected to the surface of the dielectric oxide film 18 of the element sheet 19 in the first embodiment, in the present embodiment, the anode lead 20 and the anode lead 20 are connected to the element sheet 19. When joining the cathode lead-out leads 21, the difference is that an insulating part 34 is provided with an insulating resin or the like around each lead-out connection part as shown in FIG. 4, and otherwise the same as in the first embodiment. Was manufactured.
[0039]
As described above, by providing the insulating portion 34 around the anode lead 20 and the cathode lead 21, each lead can be firmly fixed to both surfaces of the element sheet 19. The contact resistance with the foil can be reduced.
[0040]
【The invention's effect】
As described above, according to the present invention, one side of the aluminum foil is wound through a separator impregnated with a driving electrolyte so that it functions as a large-capacity capacitor, and the other side faces through a dielectric film. Provides a capacitor that acts as a capacitor with a low ESR value at high frequencies and integrates a capacitor with a large capacitance value that absorbs low frequencies and a capacitor with a low ESR value at high frequencies, and that can absorb noise from low frequencies to high frequencies. can do.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a manufacturing process of a capacitor according to a first embodiment of the present invention. FIG. 2 is a diagram illustrating the manufacturing process. FIG. 3 is a diagram illustrating the manufacturing process. Sectional view for explaining a configuration when lead-out leads are connected to an element sheet, which is a main part of the capacitor according to the fourth embodiment.
DESCRIPTION OF SYMBOLS 11 Dielectric film 12 Aluminum foil 15 Electrode sheet 18 Dielectric oxide film 19 Element sheet 20 Anode lead 21 Cathode lead 22, 24 Separator 25 Capacitor element

Claims (5)

Laminating an aluminum foil on both sides of a dielectric film to form an electrode sheet, roughening the surface of the aluminum foil of the electrode sheet by etching, forming at least one surface of the aluminum foil into a chemical oxidation treatment, A step of forming a film, and cutting the electrode sheet on which the dielectric oxide film is formed into a predetermined size, connecting an anode and a cathode lead to each aluminum foil, and winding together with a separator to form a capacitor element. A method for manufacturing a capacitor, comprising: a step of storing the capacitor element together with a driving electrolyte in a cylindrical metal case having a bottom and sealing an open end of the metal case with a sealing material. A step of forming an electrode sheet by disposing and laminating an aluminum foil having a dielectric oxide film formed on at least one side on both sides of the dielectric film, and cutting the electrode sheet into specified dimensions and forming an anode and a cathode on each aluminum foil; Connecting the extraction lead and winding it together with the separator to form a capacitor element, storing this capacitor element together with the driving electrolyte in a bottomed cylindrical metal case and sealing the open end of this metal case with a sealing material And producing the capacitor. The method for manufacturing a capacitor according to claim 1, wherein the step of forming the electrode sheet includes a step of half-melting and laminating the dielectric film by heating from the surface of the aluminum foil. The method for manufacturing a capacitor according to claim 1, wherein the step of forming the electrode sheet includes a step of bonding the laminate using an insulating adhesive. The method according to claim 1, wherein the step of connecting the lead of the anode and the cathode to the aluminum foil and winding the capacitor together with the separator to form a capacitor element includes the step of forming an insulating portion around the connection of the lead of the anode and the cathode. Manufacturing method of capacitor.

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