JP2003022928A - Laminated metallized film capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve safety and reliability without dielectric breakdown involving smoking and firing by obtaining a capacitor element, which is excellent in current resistance and voltage characteristic, readily at a low cost. SOLUTION: The laminated metallized film capacitor has a capacitor element which is obtained by stacking a pair of metallized films wherein a zinc-based deposited electrode metal is formed in one side of a dielectric film, or a both- sided metallized film and a non-metallized film formed in both sides of a dielectric film in superposition and cutting a matrix capacitor wherein an electrode is formed in both edge faces of a laminated film. Armoring resin is filled up with the cut surface of a capacitor element 7 coated for protection with a sheet-like protection film 6. Thereby, it is possible to improve outgassing during self recovery and to prevent electric short circuit caused by rapid inner pressure rise and dielectric breakdown involving smoking and firing by relaxing adhesion between a cut surface and armoring resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated metallized film capacitor for capacitors for electric equipment and capacitors for electronic equipment.

[0002]

2. Description of the Related Art Conventionally, a metallized film capacitor using a metallized film in which an electrode metal is vapor-deposited on the surface of a dielectric film causes a partial dielectric breakdown in a capacitor element as shown in FIG. Also, since it has an excellent self-recovery function of recovering insulation by melting or scattering the electrode peripheral part 43 by the short-circuit current 42 at the voltage breakdown point 41, it is widely used in various electric and electronic devices.

Further, in the prior art, research and development for further miniaturization, higher performance and lower cost of a laminated metallized capacitor which can be efficiently produced from an oval type by winding a capacitor element shape is actively conducted. ing. What is a laminated metallized capacitor?
Whereas a conventional wound film capacitor winds a metallized film around a winding shaft, extracts the wound material from the winding shaft, and metallizes it while winding it around a winding bobbin to form one unit capacitor. A manufacturing method in which a metallized film is wound on a relatively large drum and a mother capacitor 52 formed by applying metallikon 51 to both ends as shown in FIG. 5 is cut by a saw blade 53 to form a plurality of unit capacitors. Is a production method known from Japanese Patent Publication No. 28-1021.

FIG. 6 shows a conventional cut surface structure of a unit capacitor obtained by cutting a mother capacitor with a saw blade. That is, a double-sided metallized film 61 and a non-metallized film 65, in which a metal vapor deposition film 62 is deposited via a fuse portion 64, are alternately laminated on at least one side of both surfaces of a dielectric film, and metallikon electrode portions 66 are provided at both ends. Is formed. 63 is a window margin part.
In addition, since a security mechanism is provided through the fuse portion 64,
Even if a dielectric breakdown occurs in one part of the dielectric film of the whole capacitor, the evaporated electrode metal in the part related to the dielectric breakdown part is electrically cut off from the whole capacitor, and the other capacitor part is insulated. I was able to prevent it from being destroyed.

However, the insulation on the cut surface of the unit capacitor obtained by cutting is unstable because the film / metal on the cut surface of the element is melted by the frictional heat at the time of cutting, which is unstable. have. Therefore, in order to enhance the self-healing property at the cut surface, aluminum having excellent self-healing property and good insulation performance is mainly used in the laminated metallized capacitor.

However, when a metal mainly composed of aluminum is used as an electrode metal, the aluminum vapor-deposited metal causes an electrochemical reaction, so-called corrosion, due to an increase in the amount of corona due to an increase in the potential gradient and moisture contained in the film itself. , Becomes aluminum oxide. Aluminum oxide grows according to the voltage application time, and AL ₂ O
_{Since 3} is an insulating object, the capacity decrease in long-term use,
There is a drawback that tan δ increase may occur, and there are major problems in the life characteristics and capacity increase of the laminated metallized film capacitor. Therefore, even in a laminated metallized capacitor, an attempt has been made to shift from conventional aluminum to an electrode metal mainly composed of zinc having excellent characteristics of withstanding current and voltage.

[0007]

However, at the time of cutting, frictional heat of the cutting blade stretches the metal film and the vapor deposition film electrode,
In the conventional method for manufacturing a laminated metallized capacitor in which insulation between cut surfaces is secured by fusing the film layers with a melt of film and metal, zinc has a lower melting point than aluminum, so the meltability of the cut surface is higher. In particular, when the capacitor element is sealed by the exterior resin, flammable decomposition gas such as film and metal generated at the time of self-recovery cannot pass through the molten film and is filled between the film layers, and the safety mechanism is hard to operate.
Eventually, dielectric breakdown occurs with ignition and smoke. Further, when a metal mainly containing zinc is used as an electrode metal, the electrode film thickness becomes thicker than that of aluminum at the same surface resistance value, and thus self-recovery requires more energy than aluminum, and thus self-recovery easily fails. As a result, there is a phenomenon in which the discharge generated at the cut surface widens the gap between the film layers fused and the discharge enters the outside of the element or the inside of the film element, which eventually causes a continuous discharge or an electrical short circuit.

Further, Japanese Patent Laid-Open No. 7-183160 discloses that
It has been shown that a heat-shrinkable tube is placed on the outer periphery of the multilayer capacitor element to prevent the vapor deposition film and electrode material from scattering and enhance the safety. , Thickness, evaporated metal material, film resistance,
It was not always clear about the details such as the presence or absence of disconnection and whether to use direct current or alternating current.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems, and in a laminated metallized film capacitor having a structurally cut surface, by using a metal mainly containing zinc as a metal for vapor deposition, (EN) Provided is a laminated metallized film capacitor which is capable of easily obtaining a capacitor element excellent in withstanding current and voltage characteristics at a low cost with a small capacity reduction in use, and having high safety and high potential gradient design. That is.

[0010]

In order to achieve the above object, a laminated metallized film capacitor according to claim 1 of the present invention comprises a pair of vapor-deposited electrode metals mainly containing zinc formed on one surface of a dielectric film. Capacitor obtained by stacking a double-sided metallized film and a non-metallized film formed on both sides of a metallized film or a dielectric film, and cutting a mother capacitor having electrodes formed on both end faces of the laminated film. A laminated metallized film capacitor having an element, the cut surface of the capacitor element being covered and protected by a sheet-like protective film, and filled with an exterior resin.

As described above, since the exterior resin is filled in a state where the cut surface of the capacitor element is covered and protected by the sheet-like protective film, the adhesion between the cut surface and the exterior resin is alleviated, and at the time of self-recovery. It is possible to improve the gas releasing property and mitigate a sudden increase in the internal pressure. As a result, withstand current
Zinc, which has excellent voltage characteristics, can be used as a vapor deposition electrode metal, resulting in a decrease in capacity during long-term use.
It is possible to obtain a laminated metallized capacitor that does not increase an δ.

The laminated metallized film capacitor according to claim 2 is the laminated metallized film capacitor according to claim 1, in which a protective film is wrapped around the outer periphery of the capacitor element and packed with resin. In this way, since the protective film is wrapped around the outer periphery of the capacitor element and filled with the resin, the function of claim 1 can be obtained.
It is possible to prevent the exterior resin from penetrating into the metallikon portion of the electrode formation, and to avoid the deterioration of the contact between the metallikon and the vapor deposition electrode metal.

The laminated metallized film capacitor according to claim 3 is the laminated metallized film capacitor according to claim 1 or 2, wherein the protective film sags the cut surface side of the capacitor element, and the protective film is provided between the cut surface and the protective film. 0.0
A space of 2 mm or more and 0.5 mm or less was provided. In this way, the protective film sags the cut surface side of the capacitor element, and the cut film and the protective film have a thickness of 0.02 mm or more.
Since a space of 5 mm or less is provided, in addition to the effect of claim 1 or 2, when the protective film covers the cut surface of the capacitor element, or when the resin element is wound and wrapped around the outer peripheral portion of the capacitor element, The discharge energy generated at the cut surface, and the flammable gas generated at the time of discharge or self-recovery can be released to the space formed on both sides of the cut surface, preventing their infiltration into the capacitor element, and continuous inside. Higher safety can be obtained by avoiding discharge and electrical short circuit.

The space between the cut surface and the protective film is 0.
When it is less than 02 mm, the large improvement of gas escape property according to claims 1 and 2 is not seen, and when it is more than 0.5 mm, the capacitor element is adversely affected by moisture remaining in the space formed by the protective film. 0.0
About 2 mm to 0.5 mm is desirable.

The laminated metallized film capacitor according to claim 4 is the laminated metallized film capacitor according to claim 1, 2, or 3, wherein the protective film is either a polyethylene-based film or a polypropylene-based film. As described above, since the protective film is either a polyethylene-based film or a polypropylene-based film, the cut surface is generally covered by using a polyethylene or polypropylene film having excellent gas permeability and heat resistance as the protective film. , Even if wrapped, seals the gas generated during self-recovery
High safety can be ensured without being filled and without impairing the effect even in continuous use with heat generation.

The laminated metallized film capacitor according to claim 5 is the laminated metallized film capacitor according to any one of claims 1, 2, 3 or 4, wherein the exterior resin is an epoxy resin, a urethane resin, a phenol resin or a silicone resin. It is a curable resin or a UV curable resin. As described above, since the exterior resin is a thermosetting resin such as an epoxy resin, a urethane resin, a phenol resin, or a silicon resin or a UV curing resin, it is possible to use the exterior resin properly according to the manufacturing process and the number of steps.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a sectional view of a laminated metallized film capacitor according to a first embodiment of the present invention.

As shown in FIG. 1, in this laminated metallized film capacitor, a vapor-deposited electrode metal mainly containing zinc was formed on one surface of a dielectric film, or on both surfaces of the dielectric film. A capacitor element 7 is obtained by stacking a double-sided metallized film and a non-metallized film on each other, and cutting a mother capacitor having electrodes formed on both end surfaces of the laminated film. Further, after covering the cut surface 4 with the sheet-like protective film 6 on the outer periphery of the capacitor element 7 obtained by cutting the mother capacitor,
The electrode terminal 5 is welded to the electrode extraction metallikon 3 and is inserted into the resin case 1, and then the exterior resin 2 is filled. This allows
By relaxing the adhesion between the film / metal melt near the cut surface and the filling resin, it is possible to improve the escape of energy from discharge and the film / metal decomposition gas generated during self-recovery, and to raise the extreme internal pressure in the capacitor element. It is possible to prevent insulation breakdown that may cause smoke and fire in the capacitor.

FIG. 2 is a sectional view of a laminated metallized film capacitor according to a second embodiment of the present invention. As shown in FIG. 2, the protective film 6 was wrapped around the outer periphery of the capacitor element 7 and was packed with resin.

In this embodiment, it is possible to prevent the exterior resin 2 from penetrating into the metallikon portion 3 for forming an electrode and to prevent the contact between the metallikon 3 and the vapor deposition electrode metal from being lowered. Other configuration effects are similar to those of the first embodiment.

FIG. 3 is a sectional view of a laminated metallized film capacitor according to a third embodiment of the present invention. As shown in FIG. 3, as in the second embodiment, the protective film 6 is wrapped around the outer periphery of the capacitor element 7 and is packed with resin.
The cut surface side was slackened, and a space / gap 8 of 0.02 mm or more and 0.5 mm or less was provided between the cut surface 4 and the protective film 6. When the space 8 is 0.02 mm or less, no significant improvement in gas release property is observed, and when the space 8 is 0.5 mm or more,
Since the capacitor element 7 is adversely affected by moisture remaining in the space formed by the protective film 6, it is desirable that the thickness is about 0.02 mm to 0.5 mm.

In this embodiment, when the protective film is wrapped around the outer periphery of the capacitor element 7 and filled with resin, the discharge energy generated at the cut surface 4 and the flammable gas generated during discharge or self-recovery Can be escaped to the space 8 formed on both sides of the cut surface, prevent their invasion into the capacitor element 7, and avoid continuous discharge and electrical short-circuit state inside, thereby further improving safety. Can be obtained. Other configuration effects are similar to those of the first embodiment. In addition, even if the space 8 is provided in the first embodiment, the same operational effect can be obtained.

In the above embodiment, the cut surface is covered by using a polyethylene or polypropylene film, which is generally excellent in gas permeability and heat resistance, as a protective film.
High safety can be ensured without sealing or filling the gas generated at the time of self-recovery even in the case of packaging, and without impairing the effect even in continuous use with heat generation. Further, by using a thermosetting resin such as an epoxy resin, a urethane resin, a phenol resin, or a silicon resin or a UV curing resin as the exterior resin 2, it is possible to use the resin properly according to the manufacturing process and the number of steps.

[0024]

Embodiment 1 Embodiment 1 of the present invention will be described. A double-sided metallized polypropylene film in which a metal having zinc as a main component is vapor-deposited on both surfaces of a 4 μm-thick polypropylene film and electrode layers are provided, and a non-metallized polypropylene film of the same thickness of 4 μm is alternately wound on a large drum. -Laminating, metallikon is applied to both ends of the film by thermal spraying with zinc metal, further heat aging at 105 ° C, the winding drum is removed, and the large circular capacitor mother body is cut to obtain a unit capacitor.

After the cut surface of the capacitor element obtained by cutting the capacitor base is covered with a polypropylene film having a thickness of 10 μm, the metal terminals are welded or soldered with metal terminals, and then inserted into a resin case in the exterior process. , Filled with a two-part epoxy resin consisting of a main agent and a curing agent, 90 ° C
After heating for about 3 hours at room temperature, it was left at room temperature to obtain a capacitor (FIG. 1) according to one embodiment of the present invention. At the same time, as a comparative example, a capacitor element cut in the same process as in Example 1 was used.
A conventional capacitor was obtained in the same exterior process as it was without the protective film as in the conventional case.

A second embodiment of the present invention will be described. A 5 μm-thick polypropylene film was wrapped around the outer periphery of the capacitor element obtained by cutting in the same process as in Example 1 and packaged, and then a metal terminal was welded or soldered to the metallikon electrode part, followed by the same procedure. A capacitor (FIG. 2) according to one embodiment of the present invention was obtained in the exterior process.

A third embodiment of the present invention will be described. A polypropylene film having a thickness of 5 μm was cut on the outer peripheral portion of the capacitor element obtained by cutting in the same process as in Example 1 so that the cut surface side was formed so as to form a gap of about 0.1 mm between the cut surface of the capacitor element. After slackening and wrapping and wrapping,
In the same exterior process, the capacitor of one embodiment of the present invention (
Figure 3) was obtained. In the figure, 8 is a space / gap between the molded capacitor element and the wound protective film.

A fourth embodiment of the present invention will be described. A double-sided metallized polyethylene terephthalate film in which a metal mainly containing zinc is vapor-deposited on both sides of a polyethylene terephthalate film having a thickness of 5 μm and electrode layers are provided, and a non-metallized polypropylene film also having a thickness of 4 μm is alternately placed on a large drum. It is wound and laminated, and both ends of the film are subjected to metallikon by thermal spraying with zinc metal, and further 120 ° C.
After heat aging, remove the take-up drum and make a large-circle condenser body. Thereafter, the same steps as in Example 3 were carried out to obtain a capacitor according to one embodiment of the present invention shown in FIG.

A fifth embodiment of the present invention will be described. By the same steps as in Example 1, a capacitor according to one embodiment of the present invention shown in FIG. 1 in which a UV curable resin was used as the exterior resin was obtained.

The capacitors of Examples 1 to 5 and the conventional example are rated at 250 V and C = 10 μF.

The laminated metallized film capacitors of Examples 1 to 5 were subjected to a dielectric breakdown test by an AC voltage in an atmosphere at room temperature of 25 ° C. and 70 ° C. and compared with the conventional laminated metallized film capacitors. . The test was started from 200 V, and the voltage was increased by 20 V every minute thereafter, and the voltage at which the capacitance of the capacitor was ΔC = −20% or more from the initial value, or an electrical short circuit state was taken as the dielectric breakdown voltage. The results are shown in Table 1.

[0032]

[Table 1]

From Table 1 above, when a conventional laminated metallized film capacitor without a sheet-shaped protective film covering or wrapping the cut surface or the outer periphery of the element uses a vapor-deposited electrode metal mainly containing zinc, about AC300 to In contrast to the dielectric breakdown accompanied by smoking at 350 V, the laminated metallized capacitor having the structure of FIGS. 1, 2 and 3 in which the sheet-like film of the present embodiment is coated on the cut surface or packaged. Regardless of whether the dielectric film was polypropylene or polyethylene terephthalate, the safety mechanism operated at AC 600 to 660 V, and no destruction accompanied by smoking or ignition did not occur. Further, the same effect was observed when not only epoxy resin but also UV resin was used as the exterior resin. When a vapor-deposited metal electrode containing zinc as the main component is used for the dielectric film, the melting point is relatively low at about 400 ° C., so melting at the time of cutting is large, and the thickness of the film / metal molten layer becomes thicker. Since the surroundings of the elements were filled with the exterior resin without gaps, the decomposition gas of the film, metal, etc. generated during self-recovery could not flow out to the outside, and it filled between the film elements, causing an electrical short circuit. is there. On the other hand, in the present embodiment, when the cut surface is covered with a sheet-like protective film on the outer periphery of the element, and further when wound around the outer periphery, the package is protected, and a gap is formed between the protective film and the exterior resin. Further, it is possible to improve the escape property of gas generated at the time of self-recovery, prevent an electric short circuit due to a rapid increase in internal pressure, and obtain a higher withstand voltage level compared with the conventional example even when zinc is used as a vapor deposition electrode metal.

When the cut surface of the capacitor element is covered with a sheet-like protective film, or wrapped and wrapped, an adhesive or an adhesive tape having an excellent electric insulation property is used to ensure the tightness of the package. It can also be improved.

In the present embodiment, as the dielectric film and the protective film, polypropylene having a thickness of 5 μm to 10 μm, polyethylene terephthalate, etc. were used, but the present invention is not limited to this in terms of film thickness, type, etc. Similar effects can be obtained even when a film thickness, a polyethylene film, a vinyl chloride film, a polyolefin film, a polyphenylene sulfide film, or the like is used.

Similarly, in this embodiment, as the exterior resin, a two-component thermosetting epoxy resin composed of a main agent and a curing agent, UV is used.
Although a resin or the like is used, the present invention is not limited to this, and the same effect can be obtained by using a thermosetting resin such as an epoxy resin, a urethane resin, a phenol resin, or a silicone resin. As a method of curing the resin, in addition to thermosetting,
A method such as UV curing can also be applied.

[0037]

According to the laminated metallized film capacitor of the first aspect of the present invention, since the cut surface of the capacitor element is covered and protected by the sheet-like protective film and the exterior resin is filled, it is structurally cut. In a laminated metallized capacitor having a surface, even when a metal mainly containing zinc is used as a vapor-deposited metal, by covering and protecting the cut surface with a sheet-like protective film, the adhesion between the cut surface and the exterior resin is eased. By doing so, it is possible to obtain at low cost a capacitor that can improve the degassing property of decomposition gas such as film and metal generated during self-recovery, prevent electrical short circuit due to sudden increase in internal pressure, and prevent dielectric breakdown due to smoking and ignition. be able to. As a result, a laminated metallized film capacitor having a small capacity reduction over a long period of use, excellent withstand current and voltage characteristics, high safety, and a high potential gradient design can be realized.

In the second aspect, since the protective film is wrapped around the outer peripheral portion of the capacitor element and filled with the resin, the effect of the first aspect is obtained, and in addition to the effect of the first aspect, the external resin is prevented from invading the metallicon portion of the electrode formation, and the metallicon is prevented. It is possible to avoid a decrease in contact between the vapor-deposited electrode metal and.

In the third aspect of the present invention, the protective film sags the cut surface side of the capacitor element, and a space of 0.02 mm or more and 0.5 mm or less is provided between the cut surface and the protective film. In addition to the effect, when the cut surface of the capacitor element is covered with a protective film, or wrapped around the outer periphery of the capacitor element and filled with resin,
The discharge energy generated at the cut surface, and the flammable gas generated at the time of discharge or self-recovery can be released to the space formed on both sides of the cut surface, preventing their infiltration into the capacitor element, and continuous inside. Higher safety can be obtained by avoiding discharge and electrical short circuit.

In the present invention, the protective film is either a polyethylene-based film or a polypropylene-based film. Therefore, by using a polyethylene or polypropylene film, which is generally excellent in gas permeability and heat resistance, as the protective film, Even if the cut surface is covered or packaged, the gas generated during self-recovery is not sealed and filled, and even in continuous use with heat generation, the effect is not impaired and high safety can be secured.

In the fifth aspect, the exterior resin is a thermosetting resin such as an epoxy resin, a urethane resin, a phenol resin, a silicone resin or a UV curing resin.
It can be used properly according to man-hours.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a structure of a laminated metalized film capacitor according to a first embodiment of the present invention after being packaged.

FIG. 2 is a sectional view showing a structure of a laminated metalized film capacitor according to a second embodiment of the present invention after being packaged.

FIG. 3 is a sectional view showing a structure of a laminated metalized film capacitor according to a third embodiment of the present invention after being packaged.

FIG. 4 is a diagram for explaining the operation of the self-healing function.

FIG. 5 is an explanatory view for cutting a mother capacitor.

FIG. 6 is an enlarged view of a cut surface configuration of a conventional laminated metallized film capacitor.

[Explanation of symbols]

1 resin case 2 Exterior resin 3 electrode extraction metallikon 4 Cutting surface by cutting blade 5 electrode terminals 6 protective film 7 Capacitor element

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazumi Nomura             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Hiroki Takeoka             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Kohei Shioda             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 5E082 AA06 EE03 FF05 FG06 FG36

Claims (5)

[Claims] 1. A pair of metallized films in which a vapor-deposited electrode metal mainly containing zinc is formed on one side of a dielectric film, or a double-sided metallized film and non-metallized film formed on both sides of a dielectric film are superposed. A laminated metallized film capacitor having a capacitor element obtained by cutting a mother capacitor having electrodes formed on both end surfaces of the laminated film, the cut surface of the capacitor element being covered with a sheet-like protective film. A laminated metallized film capacitor characterized by being filled with an exterior resin in a protected state. 2. The laminated metallized film capacitor according to claim 1, wherein the protective film is wrapped around the outer periphery of the capacitor element and packaged and filled with resin. 3. The protective film sags the cut surface side of the capacitor element, and the distance between the cut surface and the protective film is 0.02 m.
Claim 1 or 2 which provided the space of m or more and 0.5 mm or less.
The laminated metallized film capacitor described. 4. The protective film is either a polyethylene-based film or a polypropylene-based film.
Or the laminated metallized film capacitor described in 3. 5. The laminated metallized film capacitor according to claim 1, wherein the exterior resin is a thermosetting resin such as an epoxy resin, a urethane resin, a phenol resin, a silicon resin or a UV curing resin.