JP2009277826A - Metallized film capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost high-reliability metallized film capacitor with the leakage current increase suppressed. <P>SOLUTION: The metallized film capacitor has lead electrodes 16 and 17 provided on both end surfaces of a winding body, formed by winding metal deposition electrodes 12a and 12b which is provided on both surfaces of a both-face metallization film 14, one over the other opposite each other across a second polyethylene terephthalate film 15, having no metal deposition electrode, at least the second polyethylene terephthalate film 15 having been subjected to a heat treatment for one or more hours, under a reduced pressure of 0.01 to 0.1 Torr within a temperature range of 100 to 130°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a metallized film capacitor used for various electric equipment, various power supply circuits, communication equipment, industrial equipment, and the like.

  Conventionally, a metallized film capacitor constructed by winding or laminating a metallized film with a metal such as aluminum or zinc alloy deposited on both sides or one side of an organic film such as polypropylene, polyethylene terephthalate, polyethylene naphthalate or polyphenylene sulfide. It is used in various electrical equipment and industrial equipment.

  FIG. 4 is a partial cross-sectional view showing an example of a conventional metallized film capacitor, which is produced by laminating or winding a double-sided metallized film and a non-metallized film.

  In FIG. 4, a double-sided metallized film 42 in which split electrodes 45 having fuse portions 44 are formed on both sides of a polyphenylene sulfide film (hereinafter referred to as PPS film) 41, which is a dielectric film, and a non-metallized film PPS film 43, And a polypropylene film (not shown) having a thermal contraction rate larger than that of the PPS film is wound as an outer wound film.

  Here, the pair of split electrodes 45 on the double-sided metallized film 42 are arranged so as to face each other with a PPS film 43 having no electrodes.

For example, Patent Document 1 is known as prior art document information relating to the invention of the present application.
Japanese Patent Laid-Open No. 9-82562

  The metallized film capacitor thus configured is widely used in various electrical equipment, power supply circuits, industrial equipment, etc. due to its characteristics such as excellent withstand voltage characteristics, extremely low dielectric loss (tan δ), and low leakage current. in use.

  Some dielectric films use PPS films and PP films as described above, but PPS films are expensive and PP films do not have a very high heat resistance temperature.

  For this reason, film capacitors using a polyethylene terephthalate film (hereinafter referred to as a PET film) as a dielectric film, which is suitable for downsizing and can be used up to a relatively high temperature because of its low film price and large dielectric constant, have been widely used.

  However, when a PET film is used as a dielectric film, the PET film has a higher water absorption rate than a PPS film or PP film, and when used as a metallized film capacitor wound and provided with extraction electrodes on both end faces for a long time. In addition, there is a problem that the leakage current increases and the reliability tends to decrease due to moisture in the PET film.

  Therefore, an object of the present invention is to provide an inexpensive and highly reliable metallized film capacitor that uses a PET film and suppresses an increase in leakage current.

  In order to achieve this object, the metallized film capacitor of the present invention includes a double-sided metallized film provided with metal-deposited electrodes on both sides of the first PET film, a second PET film having no metal-deposited electrode, A metallized film in which a pair of the metal vapor deposition electrodes are overlapped and wound so as to face each other through the second PET film to form a wound body, and extraction electrodes are provided on both end faces of the wound body A metallized film capacitor in which at least the second PET film is heat-treated at a reduced pressure of 0.01 to 0.1 Torr for 1 hour or more in a temperature range of 100 to 130 ° C.

  By heat-treating the PET film at a temperature range of 100 ° C. to 130 ° C. under a reduced pressure of 0.01 to 0.1 Torr for 1 hour or more, moisture contained in the PET film can be efficiently removed, and moisture is removed. The wound PET film is wound to form a wound body, and by forming extraction electrodes on both end faces of the wound body, further infiltration of moisture after winding can be prevented, thus suppressing an increase in leakage current Thus, an inexpensive and highly reliable metallized film capacitor can be provided.

  Hereinafter, the metalized film capacitor of the present invention will be described with reference to an embodiment and drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a principal part of a metallized film capacitor showing an example of the present embodiment. A margin 13 in which metal vapor deposition electrodes 12a and 12b are non-metal vapor deposition regions at the ends on both surfaces of a first PET film 11 is shown. The double-sided metallized film 14 is formed.

  The double-sided metallized film 14 and the second PET film 15 that has not been vapor-deposited on the entire surface are wound so that the pair of metal vapor-deposited electrodes 12a and 12b are opposed to each other via the second PET film 15. Thus, a wound body (not shown) is formed, and extraction electrodes 16 and 17 are formed on both end faces of the wound body.

  The second PET film 15 is also called a laminated film, and is not vapor-deposited by metal. Therefore, the second PET film 15 does not go through a heat treatment under reduced pressure accompanying metal vapor deposition.

  For this reason, after being manufactured as a film, it still absorbs moisture and the like in the air.

  Therefore, the absorbed moisture is removed by heat-treating the second PET film 15 at a temperature range of 100 ° C. to 130 ° C. under a reduced pressure of 0.01 to 0.1 Torr for 1 hour or more.

  Then, a double-sided metallized film 14 is overlapped and wound to produce a wound body, and by providing extraction electrodes 16 and 17 on both end faces of the wound body to form a metallized film capacitor, Thus, it is possible to provide an inexpensive and highly reliable metallized film capacitor that can prevent moisture intrusion after being suppressed and suppress an increase in leakage current.

  In addition, since the first PET film passes through the heat treatment under reduced pressure by the vapor deposition device when the metal vapor deposition electrodes 12a and 12b are formed on both surfaces, the above-mentioned treatment may not be particularly performed. Leakage current can be further reduced by performing the above-described treatment before forming the metal vapor-deposited electrodes 12a and 12b to make the removal of moisture from the first PET film more reliable.

  The metallized film capacitor formed as described above will be described in more detail.

  FIG. 2 is a flowchart showing a process for producing the metallized film capacitor of the present embodiment.

  In the flowchart of FIG. 2, 201 is a step of preparing a first PET film 11 having a thickness of 3.5 μm, and 202 is a double-sided metallization by forming a metal deposition electrode having a predetermined pattern on the first PET film 11. Deposition step 203 for producing the film 14 and a slit step 203 for dividing the double-sided metallized film 14 into a predetermined film width.

  On the other hand, after the step 204 of preparing the second PET film 15 having a thickness of 3.5 μm, the slit is divided into a predetermined film width by the slit step 205, and the second PET film 15 after the slit is heat treated in the step 206. Is done.

  The heat treatment is performed at a temperature range of 100 ° C. to 130 ° C. under a reduced pressure of 0.01 to 0.1 Torr for 1 hour or more.

  As an example according to this embodiment, this heat treatment was performed at 120 ° C. and 0.1 Torr for 10 hours.

  Next, the slitted double-sided metallized film 14 and the heat-treated second PET film 15 face each other with the pair of metal vapor-deposited electrodes 12 a and 12 b through the second PET film 15 in the winding step 207. Wrapped and rolled up.

  After being wound, extraction electrodes 16 and 17 are formed by metal spraying such as zinc or tin on both end faces of the wound body in the metallicon process 208.

  Then, after the aging process 209 is performed to alleviate thermal stress and to improve the adhesive strength of the film, a characteristic test such as capacitance, dielectric loss, and withstand voltage is performed in a characteristic test process 210.

  The metallized film capacitor of the example according to the present embodiment manufactured as described above and the metal of the comparative example manufactured in the same manner as the present embodiment except that the second PET film 15 is not heat-treated at step 206. FIG. 3 shows the result of measuring the leakage current of the oxidized film capacitor by applying a DC voltage of 450 V at 65 ° C.

  As is apparent from FIG. 3, in the metallized film capacitor according to the example of the present embodiment using the second PET film 15 that was heat-treated at 120 ° C. under a reduced pressure of 0.1 Torr for 10 hours, 150 hours Even after the leakage current, the leakage current is as small as about 0.2 mA.

  On the other hand, in the metallized film capacitor of the comparative example in which the heat treatment of the PET film is not performed, it can be seen that the leakage current increases rapidly and increases to about 0.9 mA after 150 hours.

  The reason why the heat treatment conditions are set to 1 hour or more under a reduced pressure of 0.01 to 0.1 Torr in a temperature range of 100 to 130 ° C. is as follows.

  If the temperature during heat treatment is less than 100 ° C, moisture adsorbed on the PET film is difficult to remove, and if it exceeds 130 ° C, the PET film may be shrunk, deformed, or denatured due to high temperature. Absent.

  Therefore, the temperature range of the heat treatment conditions is preferably 100 ° C. or more and 130 ° C. or less, and more preferably 110 ° C. to 125 ° C.

  The degree of pressure reduction during the heat treatment is preferably higher (close to vacuum), but in order to reduce the pressure to less than 0.01 Torr (1.33 Pa), it takes too much time to reach a predetermined degree of pressure reduction. Since the process time becomes long, it is not preferable. If the degree of vacuum is 0.01 Torr (13.3 Pa), it can be said that the adsorbed moisture of the PET film is sufficient.

  On the other hand, if the degree of pressure reduction during the heat treatment is low and the atmospheric pressure exceeds 0.1 Torr, the time required for moisture removal becomes long and the process time becomes long, which is not preferable.

  Therefore, it is preferable that the degree of pressure reduction during the heat treatment is 0.01 to 0.1 Torr as the atmospheric pressure.

  The heat treatment time is preferably longer, but it may be 1 hour or longer as long as the atmospheric pressure satisfies the condition of 0.01 to 0.1 Torr in the temperature range of 100 to 130 ° C.

  If the heat treatment time is less than 1 hour, depending on the width of the PET film after the slitting process, it is often heat-treated in a state of being wound on a reel, resulting in insufficient moisture removal. It is possible and not preferred.

  Therefore, the time for the heat treatment is preferably 1 hour or longer, more preferably 10 hours or longer.

  However, since the PET film may be deformed or deteriorated when exposed to a high temperature for an excessively long time, the heat treatment time is preferably 24 hours or less.

  In this embodiment, an unpressed round capacitor element is used. However, the present invention is not limited to this, and the same effect can be obtained even when the shape is stabilized by pressing into a flat type. Can do.

  Moreover, although the wound body which alternately laminated | stacked the double-sided metallized film and the laminated film was used, it is not limited to this, Even if it is the laminated body which laminated | stacked the double-sided metallized film and the laminated film Similarly, an increase in leakage current can be suppressed.

  The metallized film capacitor of the present invention is obtained by heat-treating at least a non-metal-deposited PET film used as a laminated film at a temperature range of 100 ° C. to 130 ° C. under a reduced pressure of 0.01 to 0.1 Torr for 1 hour or more. Moisture contained in the PET film can be efficiently removed, and the PET film from which moisture has been removed is wound to form a wound body, and by forming extraction electrodes on both end faces of the wound body, Since it can prevent further intrusion, it can provide an inexpensive and highly reliable metallized film capacitor that suppresses increase in leakage current, and is useful for capacitors used in various electronic equipment, industrial equipment, etc. .

Sectional drawing of the principal part of the metallized film capacitor in one embodiment of this invention Flow chart of the manufacturing process Graph showing the leakage current measurement results Partial sectional view showing an example of a conventional metallized film capacitor

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 1st PET film 12a, 12b Metal vapor deposition electrode 13 Margin 14 Double-sided metallized film 15 2nd PET film 16, 17 Extraction electrode 201 1st PET film preparation process 202 Deposition process 203 Slit process 204 2nd PET film Preparatory process 205 Slit process 206 Heat treatment process 207 Winding process 208 Metallicon process 209 Aging process 210 Characteristic inspection process

Claims (1)

A double-sided metallized film provided with metal vapor-deposited electrodes on both sides of the first polyethylene terephthalate film and a second polyethylene terephthalate film having no metal vapor-deposited electrode are paired with the second polyethylene terephthalate film. Is a metallized film capacitor in which a winding body is formed by being overlapped and wound so as to face each other, and extraction electrodes are provided on both end faces of the winding body, and at least the second polyethylene terephthalate film is 100 What is used is a metallized film capacitor which is heat-treated at a reduced pressure of 0.01 to 0.1 Torr for 1 hour or more in a temperature range of from C to 130C.

Images