JPH04284616A - Manufacture of solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To manufacture a solid electrolytic capacitor which restrains the breakage of an electrolyte layer or the like on the surface of an anode body, which makes the hermetically sealing property of the inside good, whose reliability is high and which is thin. CONSTITUTION:A plurality of through holes 21 are formed in advance in a substrate 20; an electrolyte layer 3 is formed in desired parts; after that, the substrate 20 is cut between the individual through holes 21. Since only parts between the individual through holes 21 are cut at the cutting process of individual anode bodies 1, it is possible to restrain a stress onto an oxide film layer and the electrolyte layer 3 formed on the substrate to a minimum.

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 chip-type solid electrolytic capacitor using an organic conductive compound.

0002

2. Description of the Related Art In recent years, electronic components have been made into chips due to the demand for smaller electronic devices and more efficient mounting on printed circuit boards. Along with this, there is an increasing demand for electrolytic capacitors to be made into chips and have a lower profile.

In recent years, tetracyanoquinodimethane (T
It has been proposed that organic conductive compounds such as CNQ) and polypyrrole are applied to solid electrolytic capacitors. Solid electrolytic capacitors using these organic conductive compounds are
It has higher conductivity than conventional solid electrolytes made of metal oxide semiconductors such as manganese dioxide, and polypyrrole in particular has excellent heat resistance because the electrolyte is a polymer, so it is said to be ideal for chipping. .

[0004] This polypyrrole is produced on the surface of the anode body by chemical polymerization, electrolytic polymerization, gas phase polymerization, etc. of pyrrole. However, the mechanical strength of polypyrrole itself is weak, and depending on the electrode lead-out structure, lead wires and the like may destroy the electrolyte layer during the connection process. Alternatively, mechanical stress applied to the lead wire after the connection process may affect the electrolyte layer, making it difficult to obtain desired characteristics.

[0005] Therefore, an oxide film layer, an electrolyte layer, and a conductive layer are formed on the surface of the anode body, and a strip-shaped cathode body is placed on the surface of the conductive layer to reduce stress on the electrolyte layer during the manufacturing process. is being considered.

[0006]

[Problems to be Solved by the Invention] However, when manufacturing solid electrolytic capacitors in which an electrolyte layer or the like is formed on the surface of the anode body, in order to improve production efficiency, it is necessary to An oxide film layer, an electrolyte layer, and a conductive layer are formed on the material, and each anode body is formed by punching or cutting the material at desired locations.

[0007] However, the stress in this punching process is sometimes applied to the electrolyte layer, making it difficult to obtain predetermined electrical characteristics. Furthermore, if the stress in the punching process is large, not only the electrolyte layer but also the oxide film layer is destroyed, causing problems such as an increase in leakage current.

On the other hand, the electrical properties of this polypyrrole tend to change easily due to moisture. Therefore,
The electrolyte layer made of polypyrrole must be sealed from the outside air. These problems can be solved by covering the outer surface of the capacitor body with a synthetic resin layer by dip molding, injection molding, etc., but the outer resin layer hinders the miniaturization and height reduction of solid electrolytic capacitors. I end up.

Therefore, as described above, it is effective to place a strip-shaped cathode body on the anode body to seal the electrolyte layer. However, when forming individual anode bodies from a plate-shaped base by means such as punching, the stress causes the surface of the anode body to deform, making it difficult to sufficiently seal the internal electrolyte layer etc. even when the cathode body is mounted. There were times when it became impossible to do so.

An object of the present invention is to suppress damage to the electrolyte layer on the surface of an anode body in a fine chip-shaped solid electrolytic capacitor, improve internal sealing performance, and provide a highly reliable thin solid electrolytic capacitor. The purpose is to manufacture capacitors.

[0011]

[Means for Solving the Problems] A method for manufacturing a solid electrolytic capacitor in which a strip-shaped cathode body is mounted on an anode body on which an oxide film layer, an electrolyte layer, and a conductive layer are sequentially formed on the surface. The method is characterized in that a plurality of through holes are provided in advance at regular intervals in the base, an electrolyte layer made of solid electrolyte is formed at desired locations, and then the base is cut between each through hole to form the anode body. .

0012

[Operation] As shown in the drawings, in the present invention, a plurality of through holes 21 are formed in the base body 20 in advance before forming the electrolyte layer 3 at desired locations on the base body 20 which is divided into individual anode bodies 1. After forming the electrolyte layer 3, the base body 20 is cut between the through holes 21. Therefore, the polymerization process for producing the electrolyte layer 3 can be performed on the continuous base body 20, and at the same time, in the process of cutting into individual anode bodies 1, only between the through holes 21 are cut, so that the base body 20 can be The stress on the oxide film layer and electrolyte layer 3 generated during the process can be suppressed to a minimum.

[0013] Furthermore, when the unevenness on the surface of the anode body 1 is flattened using a roller, press, etc. to improve the sealing performance, conventionally, the electrolyte layer 3 is formed after punching out the plate-shaped base body 20. I had to do this process before and after. However, after the electrolyte layer 3 is generated, stress from rollers etc. has a negative effect on the electrolyte layer 3, and it is not easy to transfer the fine anode body 1 and flatten its surface even before the electrolyte layer 3 is generated. There wasn't.

In the manufacturing method according to the present invention, since the anode body 1 is connected by the base body 20, the step of forming the surface of the anode body 1 flatly using a roller or the like and then forming the electrolyte layer 3 is performed. It will be easier to move to Further, since individual anode bodies 1 are formed by cutting between the through holes 21, the formation of unevenness due to cutting is suppressed to a minimum.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. 1 and 2 are process diagrams illustrating a method for manufacturing a solid electrolytic capacitor according to the present invention, and FIG. 3 is a perspective view showing a solid electrolytic capacitor obtained in an example. Further, FIG. 4 is a sectional view showing the conceptual structure of a solid electrolytic capacitor obtained according to an embodiment of the present invention, and FIG. 5 is a plan view showing a substrate used in another embodiment of the present invention.

The plate-shaped base 20 shown in FIG. 1(a) is made of a valve metal such as aluminum, and through holes 21 are formed at desired locations on the base 20, as shown in FIG. 1(b). Provided at regular intervals. In this embodiment, the through hole 21 was formed into a cross shape by punching. Next, the surface of the base body 20 is shaped into a flat shape using a roller, and the remaining surface of the base body 20 is subjected to an etching process, for example, an electrolytic etching process, to enlarge the surface area to form a rough surface.

Furthermore, a chemical conversion treatment is performed on the etched rough surface portion to form an oxide film layer. The oxide film layer is made of aluminum oxide obtained by oxidizing the surface layer of the base body 20 made of aluminum, and serves as the dielectric of the anode body 1 .

Then, as shown in FIG. 1(c), an electrolyte layer 3 made of polypyrrole is formed on the oxide film layer. The polypyrrole layer, which is the electrolyte layer 3, is prepared by immersing the base 20 in a pyrrole solution containing an oxidizing agent to form a pyrrole thin film on the surface by chemical polymerization, and then immersing the base 20 in an electrolytic solution for electrolytic polymerization in which pyrrole is dissolved. The polypyrrole is produced by immersing it in the liquid and applying a voltage, and the thickness of the produced polypyrrole is several μm to several tens of μm.

Next, a conductive layer 4 is screen printed on the surface of the electrolyte layer 3. As a result, the surface of the base 20 has a laminated structure in which the electrolyte layer 3 and the conductive layer 4 are sequentially formed as shown in FIG. The conductive layer 4 may have a multilayer structure made of carbon paste and silver paste, or a single layer structure made of a conductive adhesive containing metal powder with good conductivity.

[0020] Then, the base body 20 on which the electrolyte layer 3 etc. have been formed is cut by means such as punching between the through holes 21 to obtain individual anode bodies 1 as shown in FIG. 2(a). . In this cutting, in addition to normal punching,
Cutting with a laser improves processing accuracy.

A cathode body 5 is placed on the surface of each anode body 1, as shown in FIG. 2(b). This cathode body 5 is made of flat aluminum or its alloy, and an insulating layer 7 made of a heat-resistant synthetic resin such as epoxy resin is formed on the peripheral edge of the surface in contact with the conductive layer 4, and a cathode body 5 is formed in the center. A recess is formed in which the body 5 is exposed. Further, a cathode terminal 6 made of a solderable metal layer, such as copper, is bonded to the end of the cathode body 5. The anode body 1 and the cathode body 5 are arranged so that the electrolyte layer 3 and the conductive layer 4 of the anode body 1 are housed in the recess of the cathode body 5. As a result, as shown in FIG. 4, the anode body 1 and the cathode body 5 are joined via the insulating layer 7,
Electrolyte layer 3 comes into contact with cathode body 5 via conductive layer 4 .

Further, an anode terminal 2 for drawing out the anode is welded to the side surface of the anode body 1. The anode terminal 2 has an L-shaped cross section, and in this embodiment, a solderable metal, such as copper, is placed at the tip facing the wiring pattern of the printed circuit board, and the anode body 1 is connected to the anode terminal 2. A clad alloy in which aluminum was placed and bonded at the abutting portion was laser welded to the side surface of the anode body 1.

Furthermore, on the outer surfaces of the anode body 1 and the cathode body 5,
A heat-resistant synthetic resin, for example, a prepreg film 10 having an epoxy resin as a base, is wound around the film 10 so that its ends slightly protrude from both end surfaces of the anode body 2, and a synthetic resin layer 11 such as epoxy resin is filled. Let solidify. Then, the anode terminal 2 and cathode terminal 6 protruding from the surface of the synthetic resin layer 11 disposed at the open end of the film 10 are bent along the side and bottom surfaces of the anode body 1 and brought into close contact with the bottom surface of the anode body 1. Thus, a solid electrolytic capacitor 30 as shown in FIG. 3 is obtained.

In the solid electrolytic capacitor 30 formed as described above, at least the electrolyte layer 3 of the anode body 1 is
Since it is generated after the through-holes 21 are provided in the base body 20, the electrolyte layer 3 is not adversely affected by stress in the step of forming the through-holes 21. In addition, each through hole 2
When cutting between 1 and 2, only a small portion between the through holes 21 is cut, so the stress caused by the cutting is also minimized. Further, as in this embodiment, when the chemical conversion process is performed after providing the through holes 21 in the base 20, the base 20
Damage to the upper oxide film layer can also be minimized.

Further, as shown in FIG. 4, the electrolyte layer 3
The surface is electrically contacted with the cathode body 5 via the conductive layer 4. Therefore, it is possible to connect without using conventional methods such as bonding with lead wires, etc.
Stress during this connection process can also be suppressed. Further, the electrolyte layer 3 and the conductive layer 4 are electrically connected to the cathode body 5 at the surface, and at the same time, the cathode body 5 and the cathode body
It is sealed from the outside by the insulating layer 7.

Note that a through hole 2 is formed in the base body 20 which becomes the anode body 1.
The step of forming the substrate 1 may be performed either before or after the step of etching the base 20 to form the rough surface portion. Although not shown, the anode body 1 may be arranged on both sides of the cathode body 5. In this case, an insulating layer 7 is provided on both sides of the cathode body 5, and the electrolyte layer 3, etc. of each anode body 1 is provided in each recessed part. will be stored. When a plurality of anode bodies 1 are arranged on both sides of the cathode body 5 in this way, the capacitance is doubled, and since the anode bodies 1 are arranged on both sides, mechanical strength and sealing performance are further improved. improves.

Further, the through hole 21 provided in the base body 20 may have any other shape as long as it is suitable for separating and cutting the anode body 1 from the base body 20. For example, Figure 5 (a
), a strip-shaped through hole 22 is provided in the base 20, and as shown in FIG. Thereafter, each of the through holes 22 is cut to obtain individual anode bodies 1 (indicated by broken lines in the figure). According to this embodiment, the base body 20 after forming the electrolyte layer 3 is cut at the corner portions of the individual anode bodies 1. The stress of the cutting process at the corners of the anode body 1 is dispersed in two directions. Therefore, the stress on the electrolyte layer 3 is further reduced compared to the previous embodiment.

[0028]

[Effects of the Invention] As described above, this invention provides an oxide film layer,
In a method for manufacturing a solid electrolytic capacitor in which a strip-shaped cathode body is placed on an anode body on which an electrolyte layer and a conductive layer are sequentially formed on the surface, a plurality of through holes are provided in advance at regular intervals in a base made of a plate-shaped metal. In addition, after forming an electrolyte layer made of a solid electrolyte at a desired location, the substrate is cut between each through hole to form an anode body.
At least in the process of cutting individual anode bodies from the base body, only cutting is performed between the through holes, and the influence of mechanical stress on the electrolyte layer or oxide film layer can be suppressed to a minimum. Therefore, damage to the electrolyte layer, oxide film layer, etc. is reduced, and electrical characteristics can be improved. Furthermore, the deformation of the anode body surface due to this cutting process is reduced, and the sealing accuracy of the anode body is also improved.

Furthermore, since the electrolyte layer is formed after the through holes are formed in the substrate, even if the surface irregularities are shaped to improve the dimensional accuracy of the substrate before forming the electrolyte layer, there will be no damage to the electrolyte layer. There is no impact. Therefore, by placing a cathode body on the cut anode body, the electrolyte layer and the like can be sealed, and desired electrical characteristics can be maintained for a long period of time.

Furthermore, the step of forming an electrolyte layer or the like on the surface of the anode body can be carried out all at once on the base bodies connected by non-through holes. Therefore, there is no need to transport individual fine anode bodies, improving productivity.

[Brief explanation of the drawing]

FIG. 1 is a process diagram illustrating a method for manufacturing a solid electrolytic capacitor according to the present invention.

FIG. 2 is a process diagram illustrating a method for manufacturing a solid electrolytic capacitor according to the present invention.

FIG. 3 is a perspective view showing a solid electrolytic capacitor obtained in an example.

FIG. 4 is a sectional view showing the conceptual structure of a solid electrolytic capacitor obtained according to an example of the present invention.

FIG. 5 is a plan view showing a substrate used in another embodiment of the invention.

[Explanation of symbols]

1 Anode body 2 Anode terminal 3 Electrolyte layer 4 Conductive layer 5 Cathode body 6 Cathode terminal 7 Insulating layer 10 Film 11 Synthetic resin layer 20 Base 21 Through hole 22 Through hole 30 Solid electrolytic capacitor

Claims (1)

[Claims] Claim 1. A solid electrolytic capacitor in which a strip-shaped cathode body is placed on an anode body on which an oxide film layer, an electrolyte layer, and a conductive layer are sequentially formed on the surface. After creating holes at regular intervals and forming an electrolyte layer made of solid electrolyte at desired locations,
A method for manufacturing a solid electrolytic capacitor, comprising cutting a base between each through hole to form an anode body.