JP2006294789A - Metallized film capacitor, case molded capacitor employing it, inverter circuit, drive circuit of motor for driving vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metallized film capacitor being used for various electric powers in which stabilized performance can be exhibited in a wide temperature region by solving a matter that tanδ deteriorates as the working temperature range widens. <P>SOLUTION: In a metallized film capacitor of track type cross-section having a dimension of 60 mm or more in the long diameter direction, bonding state between a metal deposition electrode 2 and a metallicon electrode 6 formed on the end face is stabilized by setting an offset value 7, i. e. the dimension of a pair of metallized films 3 being shifted in the width direction, at 1.2 mm or above. Consequently, a stabilized contact state is held between the metallicon electrode 6 and a dielectric film 1 even if the working temperature range is widened and thermal stress is increased and excellent performance can be sustained without deteriorating tanδ. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metallized film capacitor which is used for various electrical equipment, industrial use, power use, etc., and particularly suitable for in-vehicle use, and a case mold type capacitor using the same, an inverter circuit, and a drive circuit for a vehicle drive motor It is.

  In recent years, in the automobile industry, development of technologies that are friendly to the global environment has become active, such as the introduction of hybrid vehicles (hereinafter referred to as HEVs) that run on electric motors and engines. Since such an electric motor for HEV has a high operating voltage range of several hundred volts, a metalized film capacitor having a high withstand voltage and excellent electrical characteristics is used as a capacitor used in connection with such an electric motor. It has been.

  7 (a) and 7 (b) are a developed perspective view and a sectional view of a dielectric film showing the structure of a conventional metallized film capacitor of this type. In FIG. 7, 10 is a dielectric film made of polypropylene, 11 is a metal vapor-deposited electrode formed on one side of the dielectric film 10, and 12 is a non-metal that is an exposed portion of the dielectric film 10 provided continuously in the longitudinal direction on one end side in the width direction of the dielectric film 10. It is a vapor deposition part, and thereby a metallized film is formed. Using this metallized film as a pair, the metal vapor-deposited electrodes 11 are wound so as to face each other with the dielectric film 10 therebetween, and zinc is sprayed on both end surfaces. The metallicon electrode 13 was formed.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
Japanese Patent Laid-Open No. 4-163042

  However, in the above conventional metallized film capacitor, the general electrostatic capacitance range is 0.1 to 50 μF and the operating temperature range is about −10 ° C. to + 75 ° C., whereas the electrostatic capacitance required for HEV is required. The capacity is several hundred μF or more and the operating temperature range is −40 ° C. to + 90 ° C. or more, and there is a problem that it cannot be used as it is.

  Further, since the capacitance per element of the metallized film capacitor is about several hundreds μF, in order to obtain a capacitance of several hundreds μF or more, a plurality of such metallized film capacitors are arranged in parallel. However, if the number of elements increases, there is a problem that the cost increases and the reliability decreases.

  Therefore, if the capacitance of one element can be greatly increased to several hundred μF, the number of elements can be reduced, and a metalized film capacitor for HEV can be stably manufactured at low cost. Become.

  The capacitance C of the metallized film capacitor is represented by C = ε * S / d (ε: dielectric constant, S: electrode area, d: distance between electrodes).

  Therefore, when the thickness of the dielectric film is determined from the withstand voltage characteristics, etc., it is necessary to increase the electrode area in order to increase the capacitance, that is, to use a lot of metallized film. Naturally, when the shape of the element becomes larger, the larger the shape of the element, the larger the amount of displacement due to thermal expansion and contraction, and the guaranteed temperature range for in-vehicle use is 45 ° C. or higher compared to general use. The amount of displacement due to thermal expansion and contraction is further increased.

  Further, since the metallized film capacitor is composed of a metallicon electrode having a relatively small heat shrinkage and an organic resin film having a relatively large heat shrinkage, the contact portion between the metallicon electrode and the film is most susceptible to thermal stress. Is. Therefore, since the thermal stress increases as the capacitor shape increases and the operating temperature range further increases, the contact state between the metallicon electrode and the film further deteriorates, and the electrical loss (which is one of the electrical characteristics of the capacitor due to this deterioration ( tan δ) deteriorated. In general, the increase in tan δ is desired to be 50% or less with respect to the initial value.

  The present invention solves such a conventional problem, and a metallized film capacitor capable of exhibiting stable performance in a wide temperature range, a case mold type capacitor using the same, an inverter circuit, and driving of a vehicle driving motor. The object is to provide a circuit.

  In order to solve the above-mentioned problems, the present invention provides a metal vapor-deposited electrode in which a non-metal vapor-deposited portion that becomes an exposed portion of a dielectric film remains continuously in the longitudinal direction on one end side in the width direction of a dielectric film made of polypropylene The metallized film is formed so that the non-metal vapor-deposited portions are opposite to each other, and a pair of metal vapor-deposited electrodes are placed through the dielectric film in a state where predetermined dimensions are shifted so as to spread in the width direction. In a metallized film capacitor in which the cross section is formed into a track shape by winding or laminating so as to face each other, and electrodes are formed on both end faces, the dimension in the major axis direction of the cross section of the track shape is less than 60 to 100 mm When the dimension shifted in the width direction is 1.2 mm or more, and when the dimension in the same major axis direction is less than 100 to 120 mm, the dimension shifted in the same width direction is 1.3 mm or more. Dimensions size of the major axis direction is shifted in the same width direction in the case of more than 120mm are those having the configuration as above 1.4 mm.

  As described above, the metallized film capacitor according to the present invention is used because the bonding state between the metal vapor-deposited electrode and the electrode formed on the end face is stabilized by increasing the dimension shifted in the width direction of the pair of metallized films. Even if the temperature range is widened and the thermal stress is increased, the contact state between the metallicon electrode and the film can remain stable, and excellent performance can be maintained without deteriorating tanδ. The effect is obtained.

(Embodiment)
Hereinafter, the invention described in the entire claims of the present invention will be described by using embodiments.

  FIG. 1 is a cross-sectional view showing the configuration of a metallized film capacitor according to an embodiment of the present invention, and FIGS. 2A and 2B are plan views showing a metallized film used in the metallized film capacitor. FIG. 3 is a perspective view showing the structure of the metallized film capacitor.

  1 to 3, 1 is a dielectric film made of polypropylene, and 2 is a metal vapor-deposited electrode formed by vacuum vapor deposition on the surface of the dielectric film 1, thereby forming a metallized film 3. Reference numeral 4 denotes a margin portion where the dielectric film 1 is exposed without forming the metal vapor-deposited electrode 2, and the margin portion 4 is formed on one end side of the dielectric film 1 continuously in the longitudinal direction. It is. Reference numeral 5 denotes a slit that exposes the dielectric film 1 without forming the metal vapor-deposited electrode 2, and the slits 5 are formed at equal intervals in the width direction on the dielectric film 1 to form divided electrodes. Is. In FIG. 2A, the metal vapor deposition electrode 2 is divided by the slit 5, but the longitudinal direction is connected, whereas in FIG. 2B, the longitudinal direction is divided by the slit 5. It is a thing.

  6 is a metallicon electrode formed by spraying zinc metal on both end faces of the element, and 7 is a metallized film 3 formed in this way. An offset value that is a shift amount at the time of superimposing is shown, and this offset value 7 ensures insulation.

  And after winding the metallized film 3 piled up in this way, it was made into the shape as shown in FIG. 3 by crushing so that a cross section might become a track shape, 8 in a figure is a track. The major axis direction of the cross section of the shape, 9 indicates the same minor axis direction, and thus the metallized film capacitor 10 is constituted.

  Specific examples will be described below.

Example 1
A metallized film capacitor (capacitance: 120 μF, major axis direction of track-shaped cross section: 62 mm, minor axis direction: 16 mm) was produced using a metallized film of polypropylene (PP) having a thickness of 3.1 μm. In addition, the offset value used as the shift amount of the metallized film which comprises this element was 1.2 mm, and the metallized film was made into the type of Fig.2 (a) by which the width direction was not divided | segmented completely.

  A lead terminal is connected to this element to produce a metallized film capacitor, which is put in a case made of PPS resin (Tosoh Corporation's steel; P-60, containing 40% glass fiber), and epoxy resin (Sanyu Rec Co., Ltd.). A case mold type capacitor was produced by sealing with EC285).

(Example 2)
In Example 1 described above, the metallized film was produced in the same manner as Example 1 except that the offset value as the shift amount was 1.5 mm.

(Example 3)
In Example 1 described above, the metallized film was produced in the same manner as Example 1 except that the offset value as the shift amount was 1.0 mm.

(Comparative Example 1)
In Example 1 above, the offset value, which is the shift amount of the metallized film, was 1.0 mm, and the major axis direction of the track-shaped cross section was 46 mm and the minor axis direction was 23 mm. (Note that this content shows a conventional example).

Example 4
A metallized film capacitor (capacitance: 250 μF, major axis direction of track-shaped cross section: 100 mm, minor axis direction: 21 mm) was produced using a metallized film of polypropylene (PP) having a thickness of 3.1 μm. In addition, the offset value used as the shift amount of the metallized film which comprises this element was 1.4 mm, and the metallized film was made into the type of Fig.2 (a) by which the width direction was not divided | segmented completely.

  A lead terminal is connected to this element to produce a metallized film capacitor, which is put in a case made of PPS resin (Tosoh Corporation's steel; P-60, containing 40% glass fiber), and epoxy resin (Sanyu Rec Co., Ltd.). A case mold type capacitor was produced by sealing with EC285).

(Example 5)
In Example 4 above, it was produced in the same manner as Example 4 except that the offset value as the shift amount of the metallized film was 1.8 mm.

(Example 6)
In Example 4 above, the offset value, which is the shift amount of the metallized film, is 1.3 mm, and the metal vapor deposition electrode shown in FIG. It was produced in the same manner as in Example 4 except that the divided one was used.

(Example 7)
In Example 4 above, a metallized film was produced in the same manner as Example 4 except that the offset value, which is the shift amount of the metallized film, was 1.2 mm.

(Example 8)
A metallized film capacitor (capacitance; 320 μF, major axis direction of track-shaped cross section: 120 mm, minor axis direction: 22 mm) was produced using a metallized film of polypropylene (PP) having a thickness of 3.1 μm. In addition, the offset value used as the shift amount of the metallized film which comprises this element was 1.5 mm, and the metallized film was made into the type of Fig.2 (a) by which the width direction was not divided | segmented completely.

  A lead terminal is connected to this element to produce a metallized film capacitor, which is put in a case made of PPS resin (Tosoh Corporation's steel; P-60, containing 40% glass fiber), and epoxy resin (Sanyu Rec Co., Ltd.). A case mold type capacitor was produced by sealing with EC285).

Example 9
In Example 8, a metallized film was prepared in the same manner as Example 8 except that the metal vapor deposition electrode shown in FIG. 2B was divided into 15 mm widths by slits in the width direction.

(Example 10)
In Example 8, the same procedure as in Example 8 was performed except that the offset value, which is the shift amount of the metallized film, was 1.3 mm.

  The metallized film capacitors of Examples 1 to 10 and Comparative Example 1 obtained in this manner were subjected to a thermal shock test, and the results of determining the rate of change of tan δ are shown in FIGS. In the thermal shock test, a temperature of −40 ° C. to + 95 ° C. was set to one cycle for 2 hours each, and the average value of n = 3 was shown.

  As is apparent from FIGS. 4 to 6, in Example 1 according to the present embodiment, the rate of change of tan δ is small even after 1000 cycles and is 20% or less of the initial value, but the offset value is further increased. In Example 2, the change rate of tan δ is 10% or less even after 1000 cycles, and it can be seen that the change rate of tan δ is reduced by increasing the offset value.

  On the other hand, in Example 3 where the offset value is small, the rate of change of tan δ is as large as about 50%, and in the comparative example 1 where the length-to-length ratio of the track-shaped cross section is small and the length on the major axis side is short. It can be seen that almost no change in tan δ is observed.

  In Example 4, the rate of change of tan δ after 1000 cycles is about 35% with respect to the initial value. In Example 5 in which the offset value is further increased, the rate of change of tan δ after 1000 cycles is about 15%. It can be seen that when the length of the metallicon electrode formed in a track shape is long, good results can be obtained by increasing the offset value.

  As one factor of the increase in tan δ, it is considered that the metal vapor deposition electrode is connected in the major axis direction even when the contact between the metallicon electrode and the dielectric film is deteriorated. In Example 6, since the metal vapor-deposited electrode is divided by the slit in the width direction, the degradation portion of the contact of the metallicon electrode and the dielectric film is separated, so that an increase in tan δ is suppressed, and the offset value is In small Example 7, it turns out that the change rate of tan-delta after 1000 cycles is as large as about 150%.

  In Example 8, the rate of change of tan δ after 1000 cycles is about 35% with respect to the initial value. However, in Example 9, the metal deposition electrode was divided by the slits in the width direction, so that the metallicon electrode In Example 10, where the offset value is small, the rate of change of tan δ after 1000 cycles is as large as about 150%. I understand that.

  As described above, the metallized film capacitor according to the present invention has a cross section formed in a track shape, and the width of the pair of metallized films is a metallized film capacitor in which the dimension in the major axis direction of the track shaped cross section is 60 mm or more. By increasing the offset value, which is a dimension that shifts in the direction, the bonding state between the metal vapor deposition electrode and the metallicon electrode formed on the end face is stabilized, so even if the operating temperature range becomes wide and thermal stress increases, The contact state between the electrode and the dielectric film remains stable, and excellent performance can be maintained without deteriorating tan δ.

  Accordingly, a case mold type capacitor is configured by using the metalized film capacitor according to the present invention configured as described above. Further, the case mold type capacitor is used for smoothing an inverter circuit or a drive circuit for a vehicle drive motor. By using it for smoothing, the performance can be exhibited without regret.

  In this embodiment, the shape of the element has been described by taking a track shape as an example. However, the present invention is not limited to this, and the same effect can be obtained even if it is oval or circular. It is.

  Moreover, although the polypropylene (PP) film was demonstrated as a dielectric film, this invention is not limited to this, It cannot be overemphasized that a polyethylene terephthalate film and a polystyrene sulfide film may be sufficient.

  Moreover, as an example of the metal vapor deposition electrode formed on a dielectric film, aluminum and zinc, only aluminum, silver and zinc, or these combination may be sufficient.

  Moreover, as an example of the metal sprayed as a metallicon electrode, in addition to an alloy of zinc and tin, other alloys may be used as long as the alloy is mainly composed of zinc.

  The metallized film capacitor according to the present invention has excellent performance without the deterioration of tan δ, maintaining a stable state of contact between the metallicon electrode and the dielectric film even when the operating temperature range is widened and the thermal stress increases. In particular, it is useful for smoothing an in-vehicle inverter circuit, smoothing a drive circuit of a vehicle drive motor, and the like.

Sectional drawing which showed the structure of the metallized film capacitor by one embodiment of this invention (A), (b) The top view which showed the metallized film used for the metallized film capacitor A perspective view showing the structure of the metallized film capacitor Characteristic diagram showing the rate of change of tan δ by thermal shock test of the same metallized film capacitor Characteristic diagram showing the rate of change of tan δ by thermal shock test of the same metallized film capacitor Characteristic diagram showing the rate of change of tan δ by thermal shock test of the same metallized film capacitor (A) An exploded perspective view showing a configuration of a conventional metallized film capacitor, (b) a sectional view of the dielectric film

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dielectric film 2 Metal vapor deposition electrode 3 Metallized film 4 Margin part 5 Slit 6 Metallicon electrode 7 Offset value 8 Major axis direction 9 Minor axis direction

Claims (5)

A metallized film in which a metal vapor-deposited electrode is formed on a dielectric film made of polypropylene so that a non-metal vapor-deposited portion that becomes an exposed portion of the dielectric film remains continuously in the longitudinal direction on one end side in the width direction. By winding or laminating a pair of metal vapor deposition electrodes so as to face each other with a dielectric film in a state where the vapor deposition portions are opposite to each other and are shifted in predetermined dimensions so as to spread in the width direction In a metallized film capacitor in which the cross section is formed in a track shape and electrodes are formed on both end faces, the dimension shifted in the width direction is 1.2 mm when the length in the major axis direction of the track cross section is less than 60 to 100 mm. As described above, when the dimension in the same major axis direction is less than 100 to 120 mm, the dimension shifted in the same width direction is 1.3 mm or more, and the dimension in the same major axis direction is 120 mm or more. Metalized film capacitor dimensions to shift in the same width direction is more than 1.4mm when. 2. The metallized film capacitor according to claim 1, wherein the split electrode is formed by providing slits in the metal vapor deposition electrode portion so that the non-metal vapor deposition portion which is an exposed portion of the dielectric film remains at equal intervals in the width direction. A plurality of metallized film capacitors according to claim 1 or 2 are connected by a bus bar provided with a terminal portion for external connection at one end, which is accommodated in a case, and at least the terminal portion of the bus bar is removed to form a resin. Molded case mold type capacitor. An inverter circuit using the case mold type capacitor according to claim 3 for smoothing. A drive circuit for a vehicle drive motor using the case mold type capacitor according to claim 3 for smoothing.

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