JP2007103927A - Metalized film capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metalized film capacitor capable of suppressing the heat generation even if a high ripple current is caused to flow by providing a resin layer of a material that does not deteriorate dielectric tangent in a dielectric film. <P>SOLUTION: In the metalized film capacitor in which a capacitor element 1 is wound or laminated so that a pair of metal-evaporated electrode layers 3 counters a metalized film 4, which is a dielectric film 2 on one surface or both surfaces of which metal-evaporated electrode layer 3 is formed, via the dielectric film 2, a resin layer 5 is provided between the dielectric film 2 and the metal-evaporated electrode layer 3 and a compound having a vinyl group is used in the resin layer 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a metallized film capacitor using a dielectric film provided with a resin layer.

  In recent years, film capacitors having higher withstand voltage, lower loss, and better temperature characteristics than aluminum electrolytic capacitors have been used in inverter systems for driving motors in hybrid vehicles. Since an in-vehicle capacitor is used even in a cold region or a high temperature and high humidity region, it is required to have a moisture resistance at a high temperature and a thermal shock resistance in a wide temperature range as compared with a consumer electric device. Further, there is a demand for a structure that reduces heat generation even when a high ripple current is passed.

  In particular, the state of the film surface serving as a dielectric is an important factor affecting the heat generation of the film capacitor.

  FIG. 1 is a perspective view of a metallized film capacitor. In FIG. 1, reference numeral 1 denotes a capacitor element. A metallized film 4 in which a metal vapor-deposited electrode layer 3 such as aluminum is formed on one side of a dielectric film 2 made of polypropylene (PP) or the like is used as a pair of metal vapor-deposited electrode layers 3. It is wound so as to face each other through the body film 2, and is configured so that the positive and negative electrodes of the capacitor can be electrically drawn out from both ends.

  Reference numeral 5 denotes a resin layer made of an acrylate material or the like, which is formed by coating on the dielectric film 2.

  By using an acrylate material that can be easily cured and applied, the dielectric voltage of the dielectric film 2 can be increased, and a high voltage resistant film capacitor has been realized.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
Japanese Patent No. 3101682

  However, such conventional materials and structures have a problem of deterioration of electrical characteristics. Specifically, it is a problem that the dielectric loss tangent at high temperature becomes high. This is because the carbonyl group contained in the acrylate material is composed of oxygen and carbon. Similarly, since it is slightly polarized on the positive side, the dielectric loss tangent is higher from the beginning, and at higher temperatures, the molecular motion of the acrylate material is higher, so the dielectric loss tangent is higher.

  As a result, when a ripple current is applied as a capacitor, heat is generated. However, due to the heat generation, the dielectric loss tangent is increased and further heat is generated.

  Accordingly, the present invention aims to provide a metallized film capacitor capable of suppressing heat generation even when a high ripple current is passed by providing a resin layer made of a material that does not deteriorate the dielectric loss tangent on the dielectric film in order to solve the conventional problems. To do.

  In order to solve the above-mentioned conventional problems, the present invention is characterized in that a resin layer using a compound having a vinyl group is provided between a dielectric film and a metal vapor-deposited electrode layer.

  In the capacitor of the present invention, since a resin layer using a compound having a vinyl group is provided between the dielectric film of the capacitor element and the metal vapor-deposited electrode layer, the dielectric loss tangent is not deteriorated even when a high ripple current is passed. This can be expected to suppress the heat generation of capacitor products.

  Embodiment 1 of the present invention will be described below with reference to the drawings. The description of the same configuration as the conventional capacitor is omitted.

(Embodiment 1)
In FIG. 1, reference numeral 1 denotes a capacitor element. A metallized film 4 in which an aluminum layered metal vapor deposition electrode layer 3 is formed on one side of a dielectric film 2 made of polypropylene is a pair of metal vapor deposition electrode layers 3. It is wound so as to face each other, and is configured so that the positive and negative electrodes of the capacitor can be electrically drawn out from both ends.

  Reference numeral 5 denotes a resin layer provided between the dielectric film 2 and the layered metal vapor deposition electrode layer 3, which uses a compound having a vinyl group. The resin layer 5 may be formed by vacuum deposition or coating.

  The material used for the resin layer 5 is represented by the following structural formula.

  Thus, the use of a compound having a vinyl group in the resin layer 5 is one of the technical features in the present invention. By doing so, the dielectric film 2 does not contain a carbonyl group. Since the withstand voltage of the body film 2 is increased and the dielectric loss tangent is not deteriorated, heat generation of the capacitor element product can be suppressed.

  In particular, the compound obtained by the above is characterized by being an industrially synthesizeable compound having vinyl groups at both ends and having a line-symmetric or point-symmetric structure. As a result, polarization due to the structure is suppressed, and the dielectric loss tangent is not further increased even at high temperatures.

  Further, conventionally, since the acrylate material has high hygroscopicity, since this material is not used, the moisture resistance is also improved.

In the present embodiment, aluminum is used as the metal deposition electrode layer 3, but it may be zinc or an alloy of aluminum and zinc. When aluminum is used as the metal vapor deposition electrode layer 3, the resistance value can be increased, and when zinc is used, the bonding with the extraction electrode can be enhanced, and by using these alloys, both characteristics can be obtained. Is possible.

  In FIG. 1, the thickness ratios of the dielectric film 2, the metal vapor deposition electrode layer 3, and the resin layer 5 are ignored for the sake of understanding, but the dielectric film 2 actually has a thickness of 1 to 3 μm and the metal vapor deposition electrode layer. 3 is 5 to 50 nm. In particular, by setting the resin layer 5 to 0.01 to 2.0 μm, preferably 0.01 to 0.5 μm, the non-flat portion of the dielectric film 2 is filled, and the surface roughness of the dielectric film 2 is reduced. It has the effect of doing.

  As a result, the flatness can be increased without unnecessarily increasing the overall thickness according to the surface roughness of the polypropylene film or the like, the dielectric breakdown at the thinnest portion of the dielectric film 2 can be suppressed, and the dielectric It is possible to increase the withstand voltage of the entire body film 2.

  These values are determined by the voltage used, and high withstand voltage is required in the inverter system for driving a motor of a hybrid vehicle, which is an application in the present invention.

  In the present embodiment, the resin layer 5 and the metal vapor-deposited electrode layer 3 are formed in this order on the surface of the dielectric film 2, but an oil coating layer made of silicon-based oil or fluorine-based oil is formed on the metal vapor-deposited electrode layer 3. By providing (not shown), oxidation of the metallized film can be prevented. In particular, the formation of the oil coating layer can be carried out in the same process, that is, in the vapor deposition machine, and the production cost can be further reduced and a highly reliable metallized film capacitor can be obtained.

  In addition, the dielectric film 2 in the present embodiment has a surface roughness (Ra) of 2 nm to 1000 nm. This is a surface roughness required to achieve a high withstand voltage especially for in-vehicle use.

  Moreover, although the dielectric film 2 in this Embodiment was made into polypropylene, it is not limited to this, It is not limited to this, Thermoplastic films, such as a polyethylene terephthalate, a polyethylene naphthalate, polyphenylene sulfide, or the composite heat | fever which mainly uses these films It may be a plastic film.

  And the combination of the dielectric film 2 shall not only be the same combination by said film but arbitrary combinations chosen from said film.

  Furthermore, in the present embodiment, the capacitor element 1 is of a wound type, but it may be configured by cutting a stacked one.

  Further, in the present embodiment, the metallized film 4 is provided with the metal vapor-deposited electrode layer 3 on one side of the dielectric film 2, and the resin layer 5 is provided between the dielectric film 2 and the metal vapor-deposited electrode layer 3. However, the present invention is not limited to this embodiment. The same applies even if the metal vapor-deposited electrode layer 3 is provided on both surfaces of the dielectric film 2 and the resin layer 5 is provided between the dielectric film 2 and each metal vapor-deposited electrode layer 3. It shall have an effect.

  As described above, according to the metallized film capacitor of the present invention, heat generation of the film capacitor can be suppressed, which is useful for an inverter system for driving a motor of a hybrid vehicle.

Perspective view of metalized film capacitor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Dielectric film 3 Metal vapor deposition electrode layer 4 Metallized film 5 Resin layer

Claims (4)

A metallized film capacitor in which a capacitor element is wound or laminated with a metallized film in which a metal vapor-deposited electrode layer is formed on one or both sides of a dielectric film so that the pair of metal vapor-deposited electrode layers face each other with the dielectric film interposed therebetween A metallized film capacitor according to claim 1, wherein a resin layer is provided between the dielectric film and the metal vapor deposition electrode layer, and a compound having a vinyl group is used for the resin layer. The metallized film capacitor according to claim 1, wherein aluminum, zinc, or an alloy thereof is used for the metal deposition electrode layer. The metallized film capacitor according to claim 1, wherein an oil coating layer is provided on the metal vapor deposition electrode layer of the metallized film. The metallized film capacitor according to claim 1, wherein the resin layer has a thickness of 0.01 μm to 2 μm.

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