JP2008294431A - Metallized film capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems that both end faces of a metallized film capacitor configured by making a pair of metallized films vapor-deposited on both surfaces face each other are turned to the state with many air gaps, the metallized films are bent or the like and contact strength with a metalicon electrode lowers. <P>SOLUTION: In the metallized film capacitor, first and second pseudo metal vapor deposition electrodes 5a and 5b respectively insulated from first and second metal vapor deposition electrodes 4a and 4b are provided on the end of a dielectric film 2 so as to leave the first and second insulation margins 3a and 3b of the metallized film 1. Also, the pair of metallized films 1 are laminated or wound around so that the second insulation margin 3b on the back surface faces on the same side as the first insulation margin 3a and the second metal vapor deposition electrode 4b of the back surface and the first metal vapor deposition electrode 4a of the front surface are electrically connected. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a metallized film capacitor used in electronic equipment, electrical equipment, industrial equipment, and automobiles.

  A metallized film capacitor uses a metallized film that deposits a metal made of aluminum to form an electrode (hereinafter referred to as a metal vapor deposited electrode), and the volume occupied by the electrode is smaller than that of a metal foil, making it smaller and lighter. And self-healing performance peculiar to metal deposition electrodes (when a short-circuit occurs in an insulation defect, the metal deposition electrode around the defect is evaporated and scattered by the short-circuit energy to insulate and recover the capacitor function. It has been widely used since it has high reliability against breakdown due to performance.

  FIG. 4 is a cross-sectional view of a conventional metallized film capacitor.

  In FIG. 4, reference numeral 51 denotes a metallized film, and insulating margins 53a and 53b that do not have metal deposition on the front and back surfaces (vertical direction in the figure) of the dielectric film 52, and a metal such as aluminum by vapor deposition. The metal vapor-deposited electrodes 54a and 54b are formed.

  At this time, the insulation margins 53a and 53b are formed in the metallized film 51 so as to be opposite to each other.

  The metallized film 51 thus formed is laminated or wound so that the insulation margin 53a on the front surface faces the insulation margin 53b on the back surface of the adjacent metallized film 51, and metallized electrodes 55 are provided on both end surfaces to provide a metallized film capacitor. It constitutes.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP-A-2-28915

  The metallized film capacitor having the above-described conventional configuration is such that the metal vapor-deposited electrodes 54a and 54b of the adjacent metallized film 51 are wound as electrical same polarity, but in order to provide insulation margins 53a and 53b at both ends. The both end surfaces where the metallicon electrode 55 is provided are in a state where there are many gaps, and both ends of the metallized films 51a and 51b are bent in the direction of the insulation margins 53a and 53b. It was an end.

  Thus, if the contact strength between the metallicon electrode 55 and the metallized film 51 decreases, the contact resistance increases, and heat is increased when a large current flows through the metallicon electrode 55, degrading the performance as a capacitor. There was a case.

  Therefore, an object of the present invention is to improve the contact strength between the metallized film deposited on both sides and the metallicon electrode.

  In order to achieve the above object, the present invention is configured to provide a pseudo metal vapor deposition electrode at the end of a dielectric film so that an insulation margin remains when winding a metallized film deposited on both sides. is there.

  According to the present invention, since the pseudo metal vapor deposition electrode is provided at the end of the dielectric film, there are less voids at the end face where the metallicon electrode is provided, and both ends of the metallized film are less likely to be bent. The contact strength between the metallicon electrode and the metal vapor deposition electrode is improved, and the current resistance performance is improved.

(Embodiment)
FIG. 1 is a cross-sectional view of a metallized film capacitor according to an embodiment of the present invention.

  In FIG. 1, 1 is a metallized film, and insulating margins 3a and 3b that do not have metal deposition on the front and back surfaces (vertical direction in the figure) of the dielectric film 2 and a metal such as aluminum are deposited to form electrodes. Metal vapor deposition electrodes 4a and 4b are respectively formed. Here, a lower-case letter a is attached to the surface provided on the surface of the dielectric film 2, and a lower-case letter b is attached to the surface provided on the back surface.

  At this time, the insulation margins 3a and 3b are formed in the metallized film 1 so as to be opposite to each other.

  Further, pseudo metal vapor-deposited electrodes 5a and 5b which are insulated from the metal vapor-deposited electrodes 4a and 4b on the same surface are provided at the end portions of the dielectric film 2 where the insulation margins 3a and 3b are formed.

  A pair of metallized films 1 as described above are arranged so that the insulation margin 3a on the front surface faces the insulation margin 3b on the back surface of the adjacent metallized film 1, laminated or wound, and sprayed with tin or the like on both end surfaces. Then, a metallized electrode 6 is provided to constitute a metallized film capacitor. At this time, the metal vapor deposition electrode 4b on the back surface of the metallized film 1 is electrically connected to the metal vapor deposition electrode 4a on the surface of the adjacent metallized film 1, and therefore has the same pole.

  In particular, FIG. 2 is a perspective view showing the configuration of the metallized film 1 provided with metallicon electrodes 6 on both end faces of the wound metalized film 1. As shown in FIG. 2, a pair of metallized films 1 in which pseudo metal vapor-deposited electrodes 5a and 5b (not shown) are provided at the ends of the dielectric film 2 on which insulation margins 3a and 3b (not shown) are formed. After the wire is wound, metallicon electrodes 6 are provided on both end faces to constitute the capacitor element 9.

  Although illustration of the laminated state is omitted, it is assumed that the layers are laminated so that the cross section becomes as shown in FIG.

  It is one of the technical features in the present invention that the pseudo metal vapor-deposited electrodes 5a and 5b are provided at the end portions of the dielectric film 2 where the insulation margins 3a and 3b are formed as described above. A gap between the two metallized films 1 and the metallized film 1 that is laminated or wound so as to be electrically connected to the adjacent metal vapor deposition electrodes 4a and 4b is reduced. Therefore, the contact strength between the metallicon electrode 6 and the metal vapor deposition electrode is improved, and the current resistance performance is also improved.

  As shown in FIG. 3, the heavy edge portion is formed by depositing the end portions of the metal vapor deposition electrodes 4a and 4b through the dielectric film 2 to be thicker than the thickness of the portion where the metal vapor deposition electrodes 4a and 4b are opposed to each other. In addition to forming 7a and 7b and forming the pseudo metal vapor deposition electrodes 8a and 8b to be similarly thick, the contact strength with the metallicon electrode 6 can be further improved. This has the effect of further improving the current resistance performance.

  In FIGS. 1 and 3, both of the gaps of the metallized film 1 are exaggerated and illustrated, but these may be very close or in close contact.

  In the embodiment of the present invention, the metal vapor deposition electrodes 4a and 4b are made of aluminum, but this may be made of zinc or an alloy of aluminum and zinc.

  In the present embodiment, the dielectric film 2 has an effect of improving the current resistance performance for any of polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), and polyethylene naphthalate (PEN). In particular, when a film having higher heat resistance than the conventional film such as PPS or PEN is used, the dielectric film 2 of the capacitor element 9 is thermally contracted in the heat treatment process in the conventional structure. When the gap between the layers was not generated, PPS and PEN have high heat resistance, so this heat shrinkage is small, and in some cases, the gap remains between the film layers, and the capacity in the initial state decreases. It was possible to end up.

  On the other hand, according to this embodiment, even when a dielectric film having higher heat resistance than conventional ones such as PPS and PEN is used, the capacitance is formed regardless of the thermal shrinkage of the film and the gap between the film layers. Therefore, the further effect of suppressing the capacity | capacitance fall in an initial state is produced.

(Example)
Using the metallized film capacitor according to the present embodiment, the heat resistance and capacity appearance rate of the capacitor element were evaluated.

  First, a metallized film capacitor was produced using this embodiment. At this time, as a dielectric film, a capacitor element wound with a metallized film using PPS is provided with electrode drawing means so that capacitance, tan δ, equivalent series resistance (ESR), etc. can be measured. Example 1 was adopted.

  Next, Example 2 was made the same as Example 1 except that PEN was used as the dielectric film.

  Further, Example 3 was made the same as Example 1 except that PP was used as the dielectric film for Example 1.

  Comparative Example 1, Comparative Example 2 and Comparative Example are the same as Examples 1 to 3 except that the pseudo metal deposition electrodes 5a and 5b in FIG. It was set to 3.

(Evaluation methods)
First, the capacitance value based on the area of the metal vapor deposition electrode that contributes to the capacity is obtained from the vapor deposition pattern of the metallized film constituting the capacitor element, and this is set as the “design value”.

  In the initial state immediately after the capacitor element is manufactured, the capacitance and tan δ obtained by measurement are set to “initial values”. And when the atmospheric temperature of this capacitor element was raised from -40 ° C. to the upper limit temperature and again lowered to -40 ° C. as one cycle and repeated 1000 cycles, the capacitance and tan δ were measured after carrying out the heat shock test. .

  In this heat shock test, in particular, the state where tan δ was 1.5 times or more of the initial value was determined as NG (unsuitable), and the upper limit temperature when this NG was reached was defined as the “upper limit heat resistant temperature”.

  Further, the ratio of the initial capacity actually obtained with respect to the design value was defined as “capacity appearance rate”. These are shown below (Table 1).

  As can be seen from (Table 1), according to the embodiment of the present invention, any of the examples shows a high capacity appearance rate. This is because the structure according to the present invention can form a capacity regardless of the heat shrinkage of the film and the gap between the film layers, and thus represents an effect of suppressing a decrease in capacity in the initial state.

  In addition, since the contact strength between the metallicon electrode and the film is sufficiently secured, it indicates that sufficient contact strength can be maintained even in the heat shock test.

  In particular, in Examples 1 and 2, which are high heat-resistant dielectrics, this effect is large, and even with PP, the upper limit heat-resistant temperature is slightly high.

  According to the present invention, since it is possible to improve the current resistance performance and heat resistance, it is useful as an in-vehicle metalized film capacitor that requires higher reliability when used in extremely harsh environments. It becomes.

Sectional drawing of the metallized film of the metallized film capacitor in one embodiment of the present invention The perspective view of the metallized film capacitor | condenser element in one embodiment of this invention Sectional drawing of the metallized film of the metallized film capacitor in one embodiment of the present invention Sectional view of metallized film of conventional metallized film capacitor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metallized film 2 Dielectric film 3a, 3b Insulation margin 4a, 4b Metal vapor deposition electrode 5a, 5b, 8a, 8b Pseudo metal vapor deposition electrode 6 Metallicon electrode 7a, 7b Heavy edge part 9 Capacitor element

Claims (4)

A dielectric film, a first insulating margin not deposited on the metal provided on the surface of the dielectric film, a first metal deposited electrode provided on the same surface, and a back surface of the dielectric film, In a metallized film comprising: a second insulating margin not deposited by metal provided to be opposite to the first insulating margin; and a second deposited metal electrode provided on the same back surface, Providing first and second pseudo metal vapor deposition electrodes at the ends of the dielectric film, which are insulated from the first and second metal vapor deposition electrodes, respectively, so that the first and second insulation margins remain. A pair of the metallized films face the second insulating margin on the back side on the same side as the first insulating margin on the front side, and the second metal deposition electrode on the back side and the first gold on the front side Metalized film capacitor, characterized by laminating or winding as deposition electrode are electrically connected. The end portions of the first and second metal vapor deposition electrodes are opposed to the first and second pseudo metal vapor deposition electrodes, and the first and second metal vapor deposition electrodes are opposed to each other through the dielectric film. The metallized film capacitor according to claim 1, wherein the metallized film capacitor is formed to be thicker than the thickness of the portion. The metallized film capacitor according to claim 1, wherein the dielectric film is polyphenylene sulfide or polyethylene naphthalate. 2. The metallized film capacitor according to claim 1, wherein the second metal vapor deposition electrode on the back surface and the first metal vapor deposition electrode on the front surface of the pair of metallized films are in close contact with each other.

Images