JP2677990B2 - Metallized film capacitors - Google Patents

Description

FIELD OF THE INVENTION This invention relates to metallized film capacitors. More specifically, a so-called "partially impregnated" metallized film capacitor in which the edge of a tightly wound round capacitor roll is moistened with a dielectric liquid and the inside of the capacitor roll is in a dry state with no penetration of the dielectric liquid. Regarding the improvement of. Conventional Technology There were basically two conventional technologies. First, in a so-called "total impregnation type" metallized film (hereinafter abbreviated as MF) in which all layers of the metallized film are impregnated with a dielectric liquid, a non-halogenated compound containing a silane coupling agent is used. By using a dielectric fluid, the effect of adding a silane coupling agent
A technique has been proposed in which nδ is suppressed to some extent to suppress heat generation during power application and prevent thermal destruction of a capacitor (for example, Japanese Patent Application No.
-3115). Further, as a second conventional example, there is an "part impregnated type" MF capacitor using a general dielectric liquid (for example, Japanese Patent Laid-Open No. 59-14883). Problems to be Solved by the Invention First, the infiltration of the dielectric liquid into the capacitor element has the following problems. That is, there is a problem that the plastic film swells due to the action of the dielectric liquid, the electrode film disappears, and the capacitance C is greatly reduced. Even in the second conventional capacitor, when the dielectric liquid penetrates deep into the capacitor roll during a long-term life test such as a thermal cycle, the plastic film swells in this part, causing partial destruction. There is a problem that the vapor deposition film is peeled off (disappeared) due to the occurrence of the discharge or the partial discharge, and the capacity decrease becomes large. Therefore, using a very thin plastic film as in recent years, high voltage (eg 80-100v / μ
When designing m), it was an extremely important point to solve this problem. Means for Solving the Problems In the present invention, a metallized film capacitor roll having a large resistance to permeation of a dielectric liquid and a capacitor element having a porous metallikon portion are built in a sealed case, and The dielectric fluid fills the periphery of the capacitor element, the porous metallikon part, and the edge of the metallized film capacitor roll by filling it with dielectric liquid, and the inside of the metallized film capacitor roll has not penetrated the dielectric liquid Partially impregnated metallized film capacitor having a film thickness of a capacitor element of 1 gram or more in terms of width of 20 mm, and the dielectric liquid is a non-halogen compound containing one or more kinds of silane coupling agents. It is characterized by being a chemical dielectric liquid. Then, the added silane coupling agent acts to form a very small protective film (layer) on the end surface of the capacitor roll to prevent the dielectric liquid from permeating, so that the dielectric liquid from permeating into the roll is prevented. However, the characteristic deterioration such as the decrease of the capacity C is suppressed. Examples Hereinafter, examples will be specifically described. (Example 1) A 6 μm thick polypropylene (hereinafter abbreviated as PP) film (Toray Industries, Inc., trade name: YK-41) was vapor-deposited with zinc to form an electrode. The resistance value is 3Ω / □ on the metallikon contact part and 25Ω / □ on the main electrode part, so-called heavy edge electrode. A polyethylene terephthalate film having a thickness of 38 μm was wound to form a core, two metallized films were superposed and closely wound without removing air, and a protective film was wound with a PP film having a thickness of 18 μm. After that, give zinc metallikon,
A 40 μF capacitor element was obtained. Decompress this element (10 ^-3
Thermal aging was performed at 120 ℃ / 15 Hr at ~ 10 ^-2 Torr). The device was then stored in a metal case in the usual way and filled with insulating oil. When this capacitor was disassembled and the infiltration state of the insulating oil into the element was examined, it was found that the insulating oil was infiltrated in the area around the metallikon (within 5 mm) and the outer area around the protective winding (the outermost 10 turns). Within), the inside of the element, which occupies most of the element, was in a completely dry state. This capacitor was evaluated by a high temperature voltage acceleration test. The following four types of insulating oil were used, and the results are shown in FIG. Oil A: Dioctyl phthalate (hereinafter abbreviated as DOP) and epoxy-based additive (New Nippon Rika Co., Ltd. product name: Sanso Sizer E
-9000; 1% by weight) added. Oil B: The above epoxy additive (1% by weight) and silane coupling agent (r-methacryloxypropyltrimethoxysilane; 1% by weight were added to DOP. Oil C: DOP (70) and phenylxylylethane ( 30) The above epoxy additive (1% by weight) is added to the mixed oil D oil: DOP (70) and phenoxysilylethane (30) are mixed with the above epoxy additive (1% by weight) and the above Addition of silane coupling agent (1% by weight) From these results, it is found that the insulating oil added with the silane coupling agent shows a very small capacity decrease after the life test. It has been found that the addition of the amount by weight% or more is effective.Examples of the silane coupling agent used in the present invention include r-methacryloxypropyltrimethoxysilane and r-glycidoxypropylto. Silane, r
-Chloropropyltrimethoxysilane, r-mercaptopropyltrimethoxysilane, r-aminopropyltrimethoxysilane, N-β (aminoethyl) r-aminopropyltrimethoxysilane, N-β (aminoethyl) r
-Aminopropylmethyldimethoxysilane, vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, etc., and the object of the present invention can be achieved when at least one of these is added to the non-halogenated dielectric liquid. . As the non-halogenated dielectric liquid, insulating oil conventionally used for capacitors can be applied, for example, DOP, esters such as tricresyl phosphate, rapeseed oil, castor oil,
Vegetable oils such as cottonseed oil, glycols such as polypropylene glycol and polyethylene glycol, glycerines, finylxylylethane and alkylnaphthalene,
Alternatively, alkyl benzene, triallyldiethane, dibenzyltoluene, dialkyldiphenyl, aromatic hydrocarbons such as phenylcumylethane, mineral oil, polybutene, silicone oil, etc. may be used alone or in combination of two or more, and as necessary. The following epoxy additives are used by adding 0.05% by weight or more. Epoxy additives include dipentenedioxide, vinylcyclohexenedioxide, bis-2,3-epoxycyclopentyl ether, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, bis-3,4-epoxy. 6-methylhexyl methyl adipate, di2-ethylhexyl-4,5 epoxycyclohexane-1,2 dicarboxylate and the like. For the electrodes, vapor-deposited films of Al, Zn, Sn, Ni, Co, Mo, Ti, Ni-Cr, Ta, etc. are used, and uniform vapor deposition or heavy edge vapor deposition is adopted. For the plastic film, PP, polyethylene terephthalate, polystyrene, polycarbonate, polyvinylidene fluoride, polyethylene, polyphenylene sulfide, polyimide, aramid, polyether sulfone, polyarylate, polysulfone, etc., alone or
Used in combination. The winding core of the element may be a plastic film winding body or a plastic molded body. In order to wind the element round and hard and densely, an appropriate film tension is required, and in particular air entrapment and winding disorder must be strictly avoided. That is, this is because the dielectric liquid penetrates into that portion and causes characteristic deterioration. Further, by giving the element film an adhesive strength of 1 gram or more in terms of 20 mm width, it is possible to obtain a capacitor that also has resistance to thermal cycling. (Comparative Example) A "total impregnation type" capacitor was prototyped (using the same metallized film as in Example 1) by relatively softly winding.
Here, D oil (containing a silane coupling agent) was used. Although the same life test was conducted, the capacity was greatly reduced as shown in FIG. It was revealed that the effect of the present invention can be obtained by "partially impregnating" the element wound more tightly than the above-mentioned Examples and Comparative Examples with the dielectric liquid to which the silane coupling agent was added. EFFECTS OF THE INVENTION The present invention has the following excellent effects. (I) A silane coupling agent added to the dielectric fluid acts on the edge of the metallized film capacitor roll to form a protective film that prevents the dielectric fluid from penetrating, preventing the dielectric fluid from entering the capacitor element. Therefore, the swelling of the plastic film due to the dielectric liquid can be prevented, and the peeling or disappearance of the metal electrode film can be prevented, so that the metallized film capacitor with extremely small capacitance reduction can be realized. (Ii) Since the adhesive strength between the film layers of the capacitor element is 1 gram or more in terms of 20 mm width, even under severe conditions such as cooling and heating cycles, there is no gap for dielectric fluid to enter between the film layers, resulting in higher performance. A capacitor is realized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are characteristic diagrams of metallized film capacitors of Examples and Comparative Examples of the present invention, respectively.

   ────────────────────────────────────────────────── ─── Continuation of front page    (56) References JP-A-59-167913 (JP, A)                 Japanese Unexamined Patent Publication No. 60-3116 (JP, A)                 Japanese Patent Publication Sho 59-14883 (JP, B2)

Claims (1)

(57) [Claims] A metallized film capacitor roll with great resistance to the penetration of dielectric liquid and a capacitor element having a porous metallikon part are built in a sealed case,
By filling the inside of the sealed case with a dielectric liquid, the periphery of the capacitor element, the porous metallikon portion and the edge of the metallized film capacitor roll are filled with the dielectric liquid, and the dielectric liquid permeates into the inside of the metallized film capacitor roll. A partially impregnated metallized film capacitor having a dry state, wherein the film of the capacitor element has an adhesive strength of 1 gram or more in terms of a width of 20 mm, and
A metallized film capacitor, wherein the dielectric liquid is a non-halogenated dielectric liquid to which one or more silane coupling agents are added. 2. The metallized film capacitor according to claim 1, wherein the metallized film uses a heavy edge deposited film as an electrode. 3. The metallized film capacitor according to claim 1, further comprising 0.1% by weight or more of a silane coupling agent.