JPH04326715A - Manufacture of metallized film capacitor - Google Patents

Abstract

PURPOSE:To provide a method wherein a metallized film capacitor which is small-sized and provided with the good connection of an electrode to an edge electrode is manufactured with good mass-productivity. CONSTITUTION:A wide metallized film is wound on a flat board-shaped bobbin 5; parts A near both end parts in the lengthwise direction of the film are heat- pressed and brought into close contact by a first pressure; the whole face of the bobbin is heat-pressed by a second pressure which is weaker than the first pressure; gaps are formed between layers of the film at an electrode extraction edge to which a chemical selective removal operation is exerted. When many gaps exist, protruding and recessed parts are formed on the film by the chemical selective removal operation. As a result, an electrode and an edge electrode can be connected satisfactorily.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to a method of manufacturing metallized film capacitors.

0002

[Background Art] In recent years, there has been a demand for electronic components to be smaller, lighter, higher performance, and lower in price, and metallized film capacitors have also been actively developed to be smaller and higher in performance. It is being done.

[0003] In response to the demand for smaller size and higher performance of metallized film capacitors, in Japanese Patent Application Laid-Open No. 1-248607, we chemically and selectively remove the electrode lead-out end face of the dielectric material to form electrodes and We proposed a manufacturing method that can obtain good electrical contact with the end electrode and sufficient adhesion strength of the end electrode.

Good electrical contact between the electrode and the end electrode;
In order to obtain sufficient adhesion strength of the end electrode, Japanese Patent Application Laid-Open No. 1-248
As shown in Japanese Patent Application No. 607, at the end face of the dielectric where the electrode is drawn out, the adjacent dielectric layer is 90% or more of the end face.
Moreover, it is necessary to form unevenness by lapping within a range not exceeding 0.2 mm. However, JP-A-1-2486
The manufacturing method shown in Publication No. 07 describes a method of chemically selectively removing the electrode extension end face of the dielectric, but the unevenness of the dielectric layer after chemically selectively removing it is described. The condition is that the adjacent dielectric layer is 90% of the electrode extension end face.
As mentioned above, there is no specific description of a method for forming the film so as to wrap it within a range not exceeding 0.2 mm.

In the conventional manufacturing method, as shown in FIG. 12(a), a metallized film 1 on which aluminum electrodes 2 formed by vacuum deposition are formed is wrapped around a dielectric film (hereinafter simply referred to as "film") 1a made of an organic material. Turn film 1
A metallized film capacitor element 39 with uniform end surfaces was formed by cutting and slitting a base material of a laminated metallized film in which electrodes 2 and electrodes 2 were alternately stacked in multiple layers. A indicates the vicinity of both ends, and B indicates a portion other than the vicinity of both ends. As shown in FIG. 12(b), there is no gap between the film layers on the end face of the capacitor element 39 in both the vicinity A of both ends and the portion B other than the vicinity of both ends. Figure 13 (
In a) and (b), reference numeral 33 indicates an electrode lead-out end face in a state before the capacitor element 39 is selectively removed chemically, and 35 indicates an electrode in a state in which the capacitor element 39 is subjected to selective chemical removal. The drawing end face 3 indicates a non-metalized part on which the electrode 2 is not formed.

[0006]

However, the electrode end surface 33 of the film 1a is chemically and selectively removed by bringing the electrode end surface 33 of the capacitor element 39 into contact with a gas containing at least a portion reactive with an organic material. There is a problem in that it is difficult to form irregularities on the electrode extension end face 33 if only this is done.

In order to form the unevenness on the electrode lead-out end face 33 by chemical selective removal as described above, it is necessary that the films are not completely in close contact with each other, that is, there is a partial gap between the film layers (not shown). A gap must exist. This is because, in the chemical selective removal process, reactive species react only with exposed organic materials and are chemically selectively removed. If there is no gap, only the film end face 31 is exposed as shown in FIG. 13(a), so only the film end face 31 is removed, and even after the chemical selective removal process, the film end face 31 is exposed as shown in FIG. 13(b). As shown in FIG. 2, the unevenness is not effectively formed and the film end face 31 remains almost even.

However, in order to form a state in which gaps exist partially between the film layers, it is necessary to weaken the film adhesion, and in such a state, the film will come apart, and the film laminate will not be connected to the electrode. There was a problem in that mechanical handling was not possible when dividing the capacitor element 39 at the drawer end face portion into individual capacitor elements 39.

[0009] The present invention solves the above-mentioned problems in the conventional manufacturing method, and it is possible to obtain good electrical contact between the electrode and the end electrode and sufficient adhesion strength of the end electrode. It is an object of the present invention to provide a method for manufacturing a metallized film capacitor that can be formed, the films do not come apart, and can be handled by a machine.

0010

[Means for Solving the Problems] In order to solve the above problems, the method for manufacturing a metallized film capacitor of the present invention includes the following steps:
A step of heat pressing the wound metallized film laminate near both ends of the bobbin in the longitudinal direction of the metallized film under a first pressure condition to bring the metallized film into close contact; a step of heat pressing under a second pressure condition that is weaker than the first pressure condition; and a step of dividing the laminate at the electrode lead-out end face into individual capacitor elements; After chemically selectively removing the electrode extension end face of the dielectric film by bringing the electrode extension end face into contact with a gas containing at least a component reactive with the organic material constituting the metallized film, the electrode extension end face is chemically and selectively removed. The method includes a step of forming an end surface electrode on the lead-out end surface.

[0011]

[Function] According to the method for manufacturing a metallized film capacitor of the present invention, with this configuration, the films are brought into close contact with each other in the vicinity of both ends of the bobbin in the longitudinal direction of the metallized film of the laminate by heat pressing under the first pressure condition. By dividing the laminate at the electrode lead-out end face, the laminate can be strong enough to be handled mechanically without coming apart when divided into individual capacitor elements.

Furthermore, since the areas other than the vicinity of both ends of the bobbin are heat-pressed only under the second pressure condition, which is weaker than the first pressure condition, gaps exist partially between the film layers, and therefore, during selective chemical removal. In addition, since the reactive species can also invade the gaps between the film layers, a part of the film surface is also chemically selectively removed, and the adjacent dielectric material is removed from the electrode lead-out end face according to the distribution of the gaps. The unevenness is formed so as to wrap the layer over 90% or more of the electrode lead-out end face and within a range not exceeding 0.2 mm. Therefore, it is possible to obtain good electrical contact between the electrode and the end electrode and sufficient adhesion strength of the end electrode.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a metallized film capacitor according to an embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, 1 is a metallized film in which an electrode 2 is formed by vacuum-depositing aluminum on one side of a polyphenylene sulfide film (dielectric film) 1a, and 3 is a non-metalized part (hereinafter referred to as , margin). Metallized film 1 is shown in Figure 3.
After winding it onto the flat bobbin 5 as shown in FIG.
As shown in a), the metallized film 1 is heat-pressed under the first pressing condition using a press plate 6 that can press only the bobbin end in the length direction (indicated by A in FIG. 1(a)). In close contact. Thereafter, as shown in FIG. 4(b), using a press plate 7 that covers the entire surface of the bobbin, the bobbin is heat pressed under a second press condition with a pressure lower than the first press condition, and then heated under the first press condition. The metallized film 1 other than the pressed portion is weakly adhered. After heat pressing, as shown in FIG. 5, the laminate 8 of the metallized film 1 is separated from the flat bobbin 5, and as shown in FIG. Divide at the corresponding position.

In FIGS. 1(a), (b) and (c), the vicinity of the longitudinal end of the capacitor element 9 is shown in FIG. 1(a).
), and is heat pressed under the first pressing conditions using the press plate 6 that presses only both ends of the capacitor element 9, as shown in FIG. 1(b). The metallized films 1 are completely in close contact with each other on the surface, and there is no gap 10 between the metallized films 1. However, since the portions other than the vicinity of both ends (indicated by B in FIG. 1(a)) are heat-pressed only under the second pressing condition of weak pressure, as shown in FIG. 1(c), the metallized film 1 The metallized films 1 are not in complete contact with each other, and the metallized films 1 are partially in point contact, and gaps 10 are partially formed between each metallized film 1.

Furthermore, since the divided capacitor element 9 has the metallized film 1 in perfect contact with each other in the area A near both ends, even if the adhesion of the film in the area B other than the area near both ends is weak, The film does not come apart and is strong enough to be handled by mechanical transfer.

As shown in FIG. 7, the divided capacitor element 9 is assembled in an iron frame 11 with a spacer 18 in between so that only the electrode extension end face 13 is exposed. At this time, by making the size of the vicinity A of the end part of the capacitor element 9 smaller than the thickness C of the iron frame 11, the vicinity A of the end part is hidden within the frame 11 and is not exposed, and both sides of the capacitor element 9 are Electrode extraction end surface 13 of portion B other than near the end portion
only is exposed.

The electrode end surface 13 of the portion B other than the vicinity of both ends of the capacitor element 9 is brought into contact with oxygen gas plasma using the oxygen plasma treatment apparatus shown in FIG. 9 to chemically select the electrode end surface 13 of the film. The electrode 2 of the metallized film 1 is exposed by removing the target, and the end face of each dielectric film 1a on the electrode extension end face 13 is formed to have an uneven surface. In FIG. 9, 21a is an upper discharge electrode having an outlet (not shown) for oxygen gas 20, 21b is a lower discharge electrode on which capacitor element 9 assembled with spacer 18 is placed on frame 11, and 19 is a pair of A high-frequency power supply that generates a high-frequency voltage applied between the discharge electrodes 21a and 21b, 20a an oxygen cylinder, 22 a vacuum vessel of an oxygen plasma processing apparatus that accommodates the pair of discharge electrodes 21a and 21b, and 23 cooling the lower discharge electrode 21b. This is cooling water. As a result of this oxygen gas plasma treatment, the film is partially in a point contact state as described above in the portion B other than the vicinity of both ends of the capacitor element 9.
Since a gap 10 is partially formed between each film, reactive species (mainly oxygen radicals) that are extracted from the oxygen gas plasma and are reactive with the organic material constituting the film are also present in the gap 10. Since the film is penetrated and selectively removed chemically from the surface of the film as well, depending on how the gaps 10 are scattered, the electrode extension end face 13 of each dielectric film 1a shown in FIG. It is processed into irregularities as shown in the figure.

As shown in FIG. 10, the end surface electrode 4 is formed on the electrode extension end surface 15 on which the unevenness shown in FIG. 2(b) is formed by metal spraying zinc using a metal spray gun 24. The metal-sprayed zinc particles are attached to the electrode lead-out end face 15.
Since the unevenness is formed on the end face electrode 4, it is possible to obtain good electrical contact with the electrode 2 and sufficient adhesion strength.

In this embodiment, as shown in FIG.
Using a metallized film 1, which was made into an electrode 2 by vacuum-depositing aluminum to a thickness of 500 Å on one side of a μm polyphenylene sulfide film (conductor film 1a),
A large number of margins 3 are irradiated with the YAG laser beam 16 to have a margin width of 0.1 mm, and each time the flat bobbin 5 rotates, the irradiation position of the YAG laser beam 16 is changed from the first position to the first position in the film width direction. By switching to the second position, the electrodes 2 of the capacitor are formed to face each other,
It was wound around a flat bobbin 5 for 1000 revolutions. Note that the length in the longitudinal direction of the metallized film 1 of the flat bobbin 5 is 300 mm.

[0021] Thereafter, 10 mm from both ends of the bobbin in the length direction of the film were heated to a pressure of 3 as the first heat press condition.
After pressing at 0 kg/cm 2 , temperature 160° C., and time 30 minutes, the entire surface of the bobbin was pressed under second heat press conditions at pressure 10 kg/cm 2 , temperature 160° C., and time 10 minutes.

Hereinafter, as described above, the laminated body 8 is separated from the flat bobbin 5, divided into each capacitor element 9, and an aluminum spacer 18 with a thickness of 0.1 mm is placed on an iron frame 11 with a frame width C of 15 mm. It was assembled with .

Thereafter, the electrode extension end face 13 of the stacked body 8 assembled in the frame 11 was chemically and selectively removed using an oxygen plasma treatment apparatus to form an electrode extension end face 15. Note that the processing conditions for the oxygen plasma processing device are an oxygen flow rate of 6
0SCCM, pressure 1.0 Torr, high frequency power 400W
And so.

After the oxygen plasma treatment, end electrodes 4 were formed by metal spraying zinc on the electrode extension end faces 15 while assembled in the frame 11, and then taken out from the frame 11 to obtain a laminated metallized film capacitor.

The thus obtained metallized film capacitor of this example (hereinafter referred to as capacitor) and Comparative Example 1 were heated under the same first heat press conditions as in the example.
kg/cm2, and the second heat press condition was a pressure of 5k.
FIG. 11 shows the results when the capacitor was subjected to a charge/discharge test when the load was increased from g/cm2 to 30 kg/cm2. In addition, in FIG. 11, the horizontal axis shows the number of charging and discharging cycles, and the vertical axis shows the dielectric loss tangent at 1 kHz. The charge/discharge test conditions are: voltage is 50 d.c.
The charging and discharging resistances were each 1 kΩ, and the back capacitor had the same capacity as the test capacitor.

As shown in FIG. 11, it can be seen that when the second heat press condition is a pressure of 20 kg/cm 2 or more, the dielectric loss tangent deteriorates significantly in the charge/discharge test. When observing the cross section of the part B other than the vicinity of the end of the capacitor when the second heat press condition was set to a pressure of 20 kg/cm2 or more, it was found that no effective unevenness was formed on the electrode lead-out end face 15, and that the electrode 2 and the end face were not effectively formed. good electrical contact with the electrode 4;
It was found that sufficient adhesion strength of the end electrode 4 was not obtained.

In addition, as Comparative Example 2, a capacitor was produced in the same manner as in the example except that only the second heat press was applied without heat pressing near both ends of the bobbin A under the first heat press conditions. . The pressure conditions of the heat press were changed from 5 kg/cm2 to 30 kg/cm2.

In Comparative Example 2, if the pressure was lower than 19 kg/cm 2 , the film would come apart when it was divided into each capacitor element 9 after heat pressing, and it could not be assembled into a frame.
It was not possible to create a capacitor. Further, as in Comparative Example 1, when the heat press condition was set to a pressure of 20 kg/cm2 or more, it was found that the dielectric loss tangent deteriorated significantly in the charge/discharge test.

As a result, in Comparative Example 2, the heat press can only be produced within a narrow range of pressure conditions between 19 kg/cm2 and 20 kg/cm2, so if the film thickness or surface roughness changes, If the film comes apart and cannot be assembled into a frame, or if there is no gap between the film layers, it is difficult to ensure good electrical contact between the electrode 2 and the end electrode 4 and sufficient adhesion strength of the end electrode 4. There is a risk that you may not get it.

In the capacitor of this example, the second heat press conditions related to good electrical contact between the electrode 2 and the end electrode 4 and sufficient adhesion strength of the end electrode 4 are different from those of Comparative Example 2. , from 5 kg/cm2 to 19 kg as in this example.
Since it is permissible in a wide range up to /cm2, it can be said that it is less susceptible to variations in film thickness and surface roughness.

In addition, in the capacitor of this embodiment, since the areas near both ends A of the capacitor element 9 are completely in close contact with each other on the surface under the first heat press condition, the areas A near both ends A of the capacitor element 9 are completely in contact with each other. Even if the adhesion of portion B is weak, the film will not come apart and has enough strength to be handled by mechanical transfer.

Although polyphenylene sulfide was used as the dielectric film material in this example, the dielectric film material is not limited to this, and may include polyethylene terephthalate, polypropylene, etc., which are commonly used for capacitors. A dielectric film made of organic material can be used. Further, the thickness of the dielectric film is not limited to this example.

Furthermore, the electrode material is not limited to aluminum, and zinc, which is commonly used for capacitors, can also be used, and the electrode forming method is not limited to vacuum evaporation.
It can be formed using methods such as sputtering and ion plating that are normally used for metallized film capacitors. Furthermore, the method for forming the margin is not limited to the laser method shown in this example, but the margin can also be formed during vapor deposition using oil or tape, which is normally used when forming electrodes on dielectric films for capacitors. Methods can also be used.

[0034] As for the configuration of the capacitor to be wound, in this example, a single-sided metallized film is shown, but the present invention is not limited to this, and a configuration in which a double-sided metalized film and a non-metalized film are wound together is also possible. The effects of the present invention can be obtained with any structure commonly used for capacitors, such as a structure made of a composite film in which a dielectric layer is formed on at least one side of a metallized film.

Furthermore, the method for dividing the laminate is not limited to a razor blade, and a saw blade, a push-cut blade, or the like may be used.

Furthermore, the conditions for chemically selectively removing the electrode extension end face of the dielectric film are not limited to those in this example; for example, CF4, SF6, N2O, etc. may be added to oxygen plasma to perform chemically selective removal The speed of target removal can be increased. Furthermore, the method of selective chemical removal is not limited to this embodiment. For example, ozone gas can be used as a chemical selective removal method, and when ozone gas is used, chemical selective removal can be performed by irradiating ultraviolet rays or adding a gas such as N2O. speed can be increased.

[0037]

[Effects of the Invention] As is clear from the description of the above embodiments, according to the method of manufacturing a metallized film capacitor of the present invention,
The divided capacitor elements have the strength to be handled by mechanical transfer, etc., and the dielectric unevenness can be stably formed on the electrode lead-out end face of the capacitor element under a wide range of pressing conditions. This makes it possible to mass produce small metalized film capacitors with excellent characteristics that are less susceptible to variations in film thickness and surface roughness.

[Brief explanation of drawings]

FIG. 1 (a) is a perspective view showing the external appearance of a divided capacitor element in a method for manufacturing a metallized film capacitor according to an embodiment of the present invention;
(c) is an enlarged view of the end surface of the electrode extension of the portion B other than the vicinity of the end of the capacitor element in (a).

[Figure 2] (a)
(b) is a cross-sectional view showing the state before the electrode end face of the same capacitor element undergoes selective chemical removal. Cross-sectional view showing the state

[Figure 3] A perspective view showing an overview of the laser margin forming process and winding process

[Fig. 4] (a) is a cross-sectional view showing an overview of the heat press process under the first condition; (b) is a cross-sectional view showing an overview of the heat press process under the second condition.

[Fig. 5] A perspective view showing an overview of the process of separating the metallized film laminate from the flat bobbin.

[Fig. 6] A perspective view showing an overview of the process of dividing each capacitor element from the same metallized film laminate.

[Figure 7] A perspective view showing an overview of the process of assembling a capacitor element into the same frame.

[Fig. 8] A perspective view showing an outline of a frame incorporating the capacitor element.

[Fig. 9] A cross-sectional view showing an outline of an oxygen gas plasma treatment apparatus used in the same chemical selective removal process.

[Figure 10] A perspective view showing an overview of the metal spraying process

[Figure 11
] A graph showing the results of subjecting metallized film capacitors to a charge/discharge test in the manufacturing method of metallized film capacitors according to an example of the present invention and a comparative example.

FIG. 12: (a) is a perspective view showing the external appearance of a divided capacitor element in a conventional method for manufacturing a metallized film capacitor; (b)
is an enlarged view of the electrode extraction end face of the divided capacitor element.

FIG. 13 (a) is a cross-sectional view showing the state before chemical selective removal of the electrode end surface of the same capacitor element; FIG. Cross-sectional view showing

[Explanation of symbols] 1 Metallized film 1a Dielectric film 2 Electrode 3 Non-metalized part (margin) A Near both ends B Parts other than near both ends 4 End electrode 5 Flat bobbin 8 Laminated body 9 Capacitor element 10 Gap 13, 15 Electrode extraction end surface

Claims (7)

[Claims] 1. A step of winding a wide metallized film having a plurality of non-metalized parts and using an organic material as a dielectric film onto a flat bobbin, and a laminate of the wound metallized film. heat-pressing the vicinity of both ends of the flat bobbin in the longitudinal direction of the metallized film under a first pressure condition to bring the metallized film into close contact with each other, and then pressing the entire surface of the laminate under the first pressure condition. a step of heat pressing under a second weak pressure condition; a step of dividing the laminate at the electrode extension end face into individual capacitor elements; and a step of heat pressing the electrode extension end face of the divided capacitor element with the metallization. Contact with a gas containing at least a component reactive with the organic material constituting the film,
A method for manufacturing a metallized film capacitor, comprising the step of selectively chemically removing the electrode extension end face of the dielectric film, and then forming an end face electrode on the electrode extension end face. 2. The method of manufacturing a metallized film capacitor according to claim 1, wherein the electrode extension end face of the dielectric is selectively removed chemically using plasma containing at least oxygen. 3. The metallized film capacitor according to claim 1, wherein the electrode extension end face of the dielectric is chemically and selectively removed using plasma containing an oxygen-containing gas added with at least one of CF4, SF6, and N2O. Production method. 4. The method for manufacturing a metallized film capacitor according to claim 1, wherein the electrode extension end face of the dielectric is chemically and selectively removed using radicals extracted from plasma containing at least oxygen. 5. The method of manufacturing a metallized film capacitor according to claim 1, wherein the electrode extension end face of the dielectric is selectively removed chemically with a gas containing at least ozone. 6. The method of manufacturing a metallized film capacitor according to claim 1, wherein the electrode extension end face of the dielectric is chemically and selectively removed with a gas containing at least ozone and N2O added thereto. 7. The method for manufacturing a metallized film capacitor according to claim 5, wherein the electrode extension end face of the dielectric material is irradiated with ultraviolet rays when selectively removing the electrode end face.