JP2010016161A - Metalized film capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve resistance to vibration by solving the problem of a failure occurring at a metallicon section in a metalized film capacitor having a case of which the upper end face is opened, one or a plurality of capacitor elements stored in the case that use metalized films, and have metallicon electrodes at both ends, an external leading terminal connected to the metallicon electrode, and a resin composition that is filled in the case and buried with the capacitor element. <P>SOLUTION: The capacitor element is buried by the resin composition filled in the case. The metallicon electrode and the external leading terminal of the metallicon electrode are coated with low-stress resins. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a metallized film capacitor in which one or more capacitor elements using a metallized film are housed in a case having an opening and filled with a resin composition.

  In recent years, reliability required for metallized film capacitors has been increasing, and similar reliability is required even in severe use environments.

  Conventionally, a capacitor element using a metallized film is housed in a case with an opening, and a metallized film capacitor filled with a resin composition is formed by winding or laminating two metallized films, After winding or laminating a metal such as zinc on the wound or laminated end faces to bring out metallicon, a capacitor element is manufactured by performing a temperature treatment called heat treatment as necessary. Next, external terminals were connected to the electrodes at both ends of the capacitor element or the plurality of capacitor elements, housed in a case, and then filled with a resin composition.

  In recent years, an inverter circuit suitable for energy saving and high efficiency has been adopted from the consideration of the environment. However, since the working voltage is high, there is a tendency to use a film capacitor among the capacitors. In particular, in applications such as on-vehicle moving bodies, conditions such as vibration resistance as well as a wide temperature range and moisture resistance have been demanded over a long period of time.

As a technique for improving the vibration resistance of a metallized film capacitor housed in such a case, Patent Document 1 discloses that an insulating rod is inserted into a core core through-hole of a capacitor element, thereby generating cracks or metallization in a metallized part. It is disclosed that disconnection at the portion can be prevented. Patent Document 2 discloses a technique of connecting lead wires (external lead electrodes) derived from a plurality of capacitor elements with a metal plate fixed to a plastic plate, and fixing the plastic plate with a fixing rod or the like. ing.
JP 2001-060529 A JP 2006-108461 A

  However, in any case, since a jig is additionally used, there is a restriction on the shape of the capacitor case, or a special jig needs to be designed.

  An object of the present invention is to eliminate the problems that occur in the metallicon part without using an additional jig and to improve the vibration resistance of the metallized film capacitor housed in the case.

As a means for solving the problems, the present invention includes a case having an open upper end surface, and one or more capacitor elements housed in the case and using metallized films and provided with metallicon electrodes at both ends. And an external lead terminal connected to the metallicon electrode, and a resin composition filled in the case to bury the capacitor element, and the metallicon electrode is covered with a low stress resin.
Further, the metallicon electrode and the external lead terminal of the metallicon electrode portion are coated with a low stress resin.

  According to the present invention, in a metallized film capacitor provided with a resin composition filled in a case and immersing a capacitor element, it is possible to eliminate a problem that occurs in a metallicon part and improve vibration resistance. .

  The case of the present invention is a container generally used for a film capacitor having an open upper end surface, and is made of plastic or metal. In the case of plastic, for example, it is made of polyethylene terephthalate, polybutylene terephthalate, polycarbonate, or polyphenylene sulfide resin. If it is a metal, it consists of aluminum, iron, stainless steel, etc., for example.

  The capacitor element of the present invention is formed by winding or laminating a metallized film on which a metal such as aluminum, copper, or zinc is deposited on a film surface such as polyethylene terephthalate or polypropylene, or by winding or laminating the metal foil. In general, a metallicon electrode is provided by spraying a metal such as aluminum. The cross-sectional shape is circular when it is wound, flat when it is crushed, and quadrilateral when it is stacked, but the side of the flat or square is flat and the storage efficiency and heat dissipation are improved.

  As the metallicon electrode of the present invention, those generally used for film capacitors can be used, which are made of metal or alloy such as copper, zinc, aluminum, tin, solder, etc., and formed by thermal spraying. In some cases, the surface of the electrode may be plated.

  The external lead terminal of the present invention is generally used for a film capacitor and has a rod shape or a plate shape. The material is, for example, a metal or alloy such as copper, aluminum, iron, nickel, stainless steel, phosphor bronze, etc. In some cases, the surface is plated with tin, solder, or the like. The plate thickness can be used without particular limitation from about 0.1 mm to 2.0 mm.

  The resin composition of the present invention is generally used for filling film capacitors, and is obtained by mixing a filler or the like with a resin such as an epoxy resin or a urethane resin as necessary. As the filler, hydroxides such as silicon, titanium, aluminum, calcium, zirconium, and magnesium, oxides, carbides, nitrides, and composites thereof can be used. If necessary, a flame retardant and an antioxidant may be added.

The low stress resin of the present invention is a flexible resin provided at the interface in order to relieve the stress generated between the interface of the metallicon electrode and the resin composition, in addition to resins such as silicone resin and fluorine-containing resin, silicon rubber, Rubbers such as butyl rubber, chloroprene rubber, butadiene rubber and polyisoprene rubber can be used. Moreover, an epoxy resin modified with silicon elastomer, butyl acrylate, acrylonitrile-butadiene rubber, styrene-butadiene rubber, or the like can be used. An acrylic polyurethane resin, a modified silicone / epoxy mixed resin composition, or the like can be used. Moreover, organic gels, such as a silicone gel and a urethane gel, can be used. If necessary, fillers, flame retardants, antioxidants and the like may be added.
The location where the low stress resin is provided is provided on the surface of the metallicon electrode at both ends of the capacitor element. Further, it is provided on the external lead terminal portion of the metallicon electrode portion and the peripheral portion of the metallicon electrode. It is preferably provided on the entire surface of the metallicon electrode, but may be partially missing. Further, the external lead terminal portion of the metallicon electrode portion and the peripheral portion of the metallicon electrode may be omitted as necessary.
Coating methods with low-stress resin include spraying, brushing, and dipping the end face, as well as unmasked parts by wrapping a mask film around the side surface of the film between the metallicon electrodes on both ends or the external lead terminal. A mask may be provided to immerse the whole, and the mask film may be removed during the latter half of the solidification.
For brushing, etc., only the metallicon electrode or only the external lead terminal part in contact with the metallicon electrode and the metallicon electrode can be coated with a low stress resin, and the remaining external lead terminal part and the resin composition must be sufficiently adhered. Can do. Further, in order to coat the metallicon electrode and the external lead terminal on the upper surface portion of the metallicon electrode portion with a low stress resin, spraying or end face dipping can be adopted, and the coating workability can be improved.
The application thickness of the low stress resin is set so that the surface of the metallicon electrode is not exposed, and does not hinder the miniaturization of the capacitor. Specifically, it is about 5 μm to 1000 μm, preferably about 20 μm to 500 μm.

According to the present invention, the capacitor element itself housed in the case is fixed by the resin composition filled and buried in the case, so that it is less likely to resonate with external vibration, and the amplitude is larger than external vibration. In addition, since the metallicon electrode portions at both ends are coated with a low-stress resin, it is possible to prevent occurrence of cracks in the metallicon electrode and disconnection at the metallicon portion in order to reduce external vibration. Also, stress that affects the electrical connection between the metallicon electrode and the metallized film is less likely to occur.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 shows a schematic cross-sectional view (a) and a schematic vertical cross-sectional view (b) of a metallized film capacitor according to the present invention. FIG. 1 shows that a capacitor element using a metallized film housed in a case having an open upper end surface is filled and buried with a resin composition, and the metallicon electrode surfaces and external lead terminals at both ends of the capacitor element This shows an example in which the metallicon electrode connecting portion and the peripheral portion of the metallicon electrode are coated with a low stress resin.
Reference numeral 1 denotes a case opened upward, which is made of metal or plastic.
Reference numeral 2 denotes a capacitor element. Two metallized films, that is, two thin strip-like insulating films (usually polyester films) in which aluminum or the like is deposited on one side to form a metal electrode are overlapped and wound a predetermined number of times. It is flattened into an oval columnar body, and a metallicon electrode 3 formed by thermal spraying of metal or alloy is provided on both end faces thereof. In FIG. 1, two capacitor elements 2 are arranged in parallel.
Reference numeral 4 denotes an external lead terminal, one end of which is connected to the metallicon electrode 3 and the other end is connected to the outside.
Reference numeral 5 denotes a low-stress resin that covers the surface of the metallicon electrode 3 at both ends of the capacitor element 2, the external lead terminal 4 portion of the metallicon electrode 3 portion, and the peripheral portion of the metallicon electrode 3.
6 is a resin composition in which a filler is added to a resin such as an epoxy resin or a urethane resin.

FIG. 2 shows a cross-sectional schematic view of another metallized film capacitor according to the present invention. An example is shown in which the surface of the metallicon electrode 3 at both ends of the capacitor element, the external lead terminal 4 portion of the metallicon electrode 3 portion, and the peripheral portion of the metallicon electrode 3 are covered with a low stress resin 5.
In particular, by covering the external lead terminal 4 portion of the metallicon electrode 3 portion with the low-stress resin 5, the stress applied to the joint between the metallicon electrode 3 and the external lead terminal 4 can be reduced.

Example 1
Aluminum is vapor-deposited on one side, two thin strip-like insulating polyester films with metal electrodes are stacked and wound, flattened into an oval column, copper on both ends, and tin sprayed on the surface A capacitor element was obtained by providing a metallicon electrode formed by: Next, two capacitor elements were arranged in parallel, and the end portion of the copper plate plated with tin processed for the external lead electrode was joined to the surface of the metallicon electrode portion by welding. Next, a silicone resin as a low-stress resin was provided in a thickness of about 20 μm to 50 μm by a brush coating method on the surface of the metallicon electrode, the metallicon electrode connecting portion of the external lead terminal, and the peripheral portion of the metallicon electrode. Next, it was housed in a case made of a polyphenylene sulfide resin and filled with a resin composition in which an epoxy resin was mixed with a filler such as magnesium oxide. The capacitance of the capacitor thus obtained was 300 μF.

(Example 2)
Using the silicone resin of Example 1 as a release material, with a spray method, the metallicon electrode surface of the metallicon electrode surface, the external lead terminal portion of the metallicon electrode portion and the metallicon electrode peripheral portion with a film thickness of about 5 μm to 20 μm It was created in the same manner as Example 1 except that it was provided.

(Comparative Example 1)
A silicone resin of Example 1 was used, and the same as Example 1 was made except that the entire capacitor element was immersed in this resin.

The above examples and comparative examples, and those using no low stress resin as Conventional Example 1, were subjected to heat cycle test, high temperature and high humidity test, vibration test at each n = 10, loss rate before and after the test The result of Table 1 was obtained from the average value of the increase values.
As a test condition, the heat cycle test is 1000 cycles at −40 ° C. to 105 ° C. High temperature and high humidity test is 85 ° C, 85%, 1000 hours. In the vibration test, the front, rear, left, right, and upper directions were set to 8 G of 5 to 200 Hz in 5 hours.
From the above test, Examples 1 and 2 of the present invention are compared with Comparative Example 1 in which a low-stress resin is provided on the entire capacitor element, and in comparison with Conventional Example 1 that does not have a low-stress resin. The result was stable against vibration and vibration.

The longitudinal cross-sectional schematic of the metallized film capacitor which concerns on this invention, and the cross-sectional schematic are shown. Figure 2 shows a cross-sectional schematic view of another metallized film capacitor according to the present invention.

Explanation of symbols

1 Case 2 Capacitor element 3 Metallicon electrode 4 External lead terminal 5 Low stress resin 6 Resin composition

Claims (2)

  A case having an open upper end surface, a single or a plurality of capacitor elements each provided with a metallicon electrode using a metallized film housed in the case, an external lead terminal connected to the metallicon electrode, A metallized film capacitor comprising a resin composition filled in a case and embedded in a capacitor element, wherein the metallicon electrode is covered with a low stress resin.   The metallized film capacitor according to claim 1, wherein a connection portion between the metallicon electrode and the metallicon electrode of the external lead terminal is covered with a low stress resin.

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