JP2007019327A - High heat-resistant film capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high heat-resistant film capacitor with characteristics of a heat-resistance, a heat-dissipation, and a withstand voltage or the like improved. <P>SOLUTION: Dielectric films 62, 67 comprises a synthetic high polymer A comprising a plurality of third organic silicon polymers consisting of a couple of a first organic silicon polymer and a second organic slicon polymer. The first organic silicon polymer has a bridge structure by a siloxane bond. The second organic silicon polymer has a coupling structure by the siloxane bond. The third organic silicon polymer comprises the first organic silicon polymer and the second organic silicon polymer alternately and linearly coupled by the siloxane bond, and has 20,000 to 800,000 weight-average molecular weight. The synthetic high polymer A has a three dimensional space structure comprising a plurality of the third organic silicon polymers coupled by an alkylene group. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a film capacitor having high heat resistance.

  In the conventional film capacitor, the dielectric film of the capacitor element is generally composed of polypropylene, polyethylene, polyester, polystyrene, or the like.

  Conventionally, in a film capacitor for electric power, from the viewpoint of safety such as fire prevention, the capacitor element is installed in a non-flammable container and filled with non-flammable insulating oil or gas. However, the use of polychlorinated biphenyl used as insulating oil and sulfur hexafluoride used as gas has been restricted from the viewpoint of protecting the global environment. Therefore, in recent years, aromatic insulating oil has been used. Aromatic insulating oils are not non-flammable, but are excellent in coexistence with dielectric films.

  On the other hand, mold-type film capacitors are widely used in electronic film capacitors. In a molded film capacitor, a capacitor element is coated with a molding material for insulation (also referred to as “mold”). That is, the mold type film capacitor is composed of a capacitor element and a covering made of a mold material. The covering is generally made of an epoxy resin.

The above-described power film capacitor may be installed in a substation or the like in the above-described state and may be naturally air-cooled. In addition, the electronic film capacitor may be installed on a printed board or the like in the above state and naturally air-cooled. Further, the above-described power and electronic film capacitors may be housed in cubicles or cases and forcedly air-cooled by a fan.
JP 2002-324727 A JP 2002-141247 A JP 2003-332168 A Japanese Patent Application No. 2003-504425 "Electrical Engineering Handbook (6th edition)" (published by the Institute of Electrical Engineers), pages 184 to 192, pages 732 to 739

  By the way, the above-described polypropylene or the like and epoxy resin are usually deteriorated at a high temperature of 180 ° C. or more, and become less flexible and hardened. Therefore, in a film capacitor in which the dielectric film is made of polypropylene or the like, and a molded film capacitor in which the cover is made of epoxy resin, the upper limit of the operating temperature must be set to a low temperature of about 70 to 125 ° C. did not become. And in these capacitors, in order not to exceed the upper limit of the operating temperature, cooling with a fan or a heat sink may be attached. In that case, there is a problem that the capacitor device becomes large.

  In any capacitor, if a large high-frequency noise, inrush current, short-circuit current, or lightning surge current flows during use, the use temperature of the capacitor may exceed the upper limit temperature. In such a case, there is a possibility that polypropylene or an epoxy resin may become hard. For this reason, when the temperature of the capacitor returns from high temperature to room temperature, a large number of cracks may occur inside polypropylene or the epoxy resin. When cracks occur, the capacitor increases in leakage current and cannot withstand a high electric field, resulting in poor voltage resistance.

  In addition, in a film capacitor in which the dielectric film is made of polypropylene or the like, the heat resistance of the dielectric film is low. There was a problem that the higher the value, the smaller the capacitance.

  Furthermore, since the thermal conductivity of the epoxy resin is 0.1 to 1.0 W / mK and is relatively low, in the molded film capacitor in which the covering is made of the epoxy resin, the heat of the capacitor element is sufficiently dissipated. Can not. Therefore, in the molded film capacitor, (1) it is necessary to set the rated capacity to be smaller than in the case of not molding, and (2) due to a relatively short inrush current, short-circuit current, or high-frequency noise, The temperature rises easily, and the voltage resistance due to the occurrence of cracks tends to decrease.

  As described above, conventional film capacitors have inferior characteristics such as heat resistance, heat dissipation, and voltage resistance.

  The present invention provides a high heat-resistant film capacitor having improved characteristics such as heat resistance, heat dissipation, and voltage resistance by improving a dielectric film and further improving a covering. Objective.

  The invention described in claim 1 is a high heat resistant film capacitor having a capacitor element composed of a dielectric film and a conductor, wherein the dielectric film comprises at least one first organosilicon polymer and at least one kind. A synthetic polymer compound A, which is formed by linking a plurality of third organosilicon polymers formed by linking with a second organosilicon polymer, is included, and the first organosilicon polymer has a crosslinked structure with a siloxane bond. The second organosilicon polymer has a linear connection structure with siloxane bonds, and the third organosilicon polymer alternates between the first organosilicon polymer and the second organosilicon polymer by siloxane bonds. And having a weight average molecular weight of 20,000 to 800,000, the synthetic polymer compound A is composed of a plurality of third organosilicon polymers. It constructed by covalently linked produced by addition reaction over, is characterized by having a three-dimensional conformation.

  The first organosilicon polymer is at least one selected from polyphenylsilsesquioxane, polymethylsilsesquioxane, polymethylphenylsilsesquioxane, polyethylsilsesquioxane, and polypropylsilsesquioxane. It is.

  The second organosilicon polymer is at least one selected from polydimethylsiloxane, polydiethylsiloxane, polydiphenylsiloxane, and polymethylphenylsiloxane.

  A siloxane bond is a Si-O bond.

  The third organosilicon polymer is constituted by connecting the first organosilicon polymer and the second organosilicon polymer alternately and linearly by siloxane bonds. For example, when the first organosilicon polymer is “X” and the second organosilicon polymer is “Y”, the third organosilicon polymer has a structure of “—X—Y—X—Y—”. . Further, for example, when two types of first organosilicon polymer and two types of second organosilicon polymer are used, the first organosilicon polymer is “X1” and “X2”, and the second organosilicon polymer is “Y1”. , "Y2", the third organosilicon polymer has a structure such as "-X1-Y1-X2-Y2-" or "-X1-Y2-X2-Y1-".

  In the synthetic polymer compound A, it is preferable that a plurality of third organosilicon polymers are connected by an alkylene group.

  The invention according to claim 2 is the invention according to claim 1, further comprising a covering body that covers the capacitor element, and the covering body contains the synthetic polymer compound A.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the first organosilicon polymer has a weight average molecular weight of 200 to 70,000, and the second organosilicon polymer is 5,000 to 200,000. It has a weight average molecular weight, and the weight average molecular weight of the first organosilicon polymer is smaller than the weight average molecular weight of the second organosilicon polymer.

  The invention according to claim 4 is the invention according to claim 1, wherein the synthetic polymer compound A contains dielectric ceramic fine particles having a dielectric constant of 5 or more, for example, a dielectric constant of 5 to 15000. . When the dielectric ceramic fine particles are mixed with the synthetic polymer compound A, they are taken into the gaps in the three-dimensional structure of the synthetic polymer compound A, that is, are filled in the synthetic polymer compound A.

  The invention according to claim 5 is the insulating ceramic according to claim 1 or 2, wherein the synthetic polymer compound A has a thermal conductivity of 4 W / mK or more, for example, a thermal conductivity of 4 to 2500 W / mK. It contains fine particles. The insulating ceramic fine particles are mixed with the synthetic polymer compound A to be taken into gaps in the three-dimensional structure of the synthetic polymer compound A, that is, filled with the synthetic polymer compound A.

  The invention according to claim 6 is the invention according to claim 4, wherein the dielectric ceramics are potassium niobate, potassium tantalate, sodium tantalate, lithium tantalate, tantalum oxide, barium titanate, titanium oxide, strontium titanate. , Lead titanate, and barium zirconate.

  The invention according to claim 7 is the invention according to claim 5, wherein the insulating ceramic is at least one of aluminum nitride, beryllium oxide, alumina, silicon carbide, diamond, and boron nitride.

  The invention according to claim 8 is the invention according to claim 4, wherein the dielectric ceramic fine particles have a particle size of 0.005 to 5 μm.

  The invention according to claim 9 is the invention according to claim 5, wherein the insulating ceramic fine particles have a particle diameter of 0.01 to 50 μm.

  The invention according to claim 10 is the invention according to claim 4, wherein the volume filling rate of the dielectric ceramic fine particles with respect to the synthetic polymer compound A is 10% vol to 80% vol.

  The invention according to claim 11 is the invention according to claim 5, wherein the volume filling rate of the insulating ceramic fine particles with respect to the synthetic polymer compound A is 15% vol to 85% vol.

  The invention according to claim 12 is the invention according to claim 4 or 5, wherein the fine particles include a plurality of types of fine particles having different particle sizes, and the particle size ratio of these fine particles is 1: 1/10 to 10/10. It is in the range of 1/1/200.

  According to the first aspect of the invention, the synthetic polymer compound A constituting the dielectric film contains the third organosilicon polymer formed by connecting the first organosilicon polymer and the second organosilicon polymer. The capacitor element can have both flexibility, heat resistance and voltage resistance.

  That is, the first organosilicon polymer is excellent in insulating properties and heat resistance, but has a very high viscosity, so that the fluidity and flexibility after curing are very poor. On the other hand, the second organosilicon polymer has good fluidity and flexibility. Therefore, by linking both polymers, the advantages of both polymers can be exhibited.

  In addition, according to the first aspect of the invention, since the dielectric film contains the synthetic polymer compound A, it is possible to improve characteristics such as heat resistance and voltage resistance of the capacitor element itself.

  According to the invention described in claim 2, the characteristics of the covering itself such as heat resistance and voltage resistance can be improved.

  Synthetic polymer compound A includes (a) metals such as copper, aluminum and stainless steel, (b) insulating materials and covering materials such as aromatic polyamide (aramid paper) and enamel, (c) epoxy resins, acrylic resins, It has very good adhesion to resins such as phenolic resins and (d) glass, and adheres firmly to these. Therefore, the synthetic polymer compound A adheres firmly to the surface of the component part of the capacitor element and the surface of the case. Therefore, it is possible to realize a strong adhesion state without a gap between the capacitor element and the covering made of the synthetic polymer compound A, and to obtain high moisture resistance. As a result, a molded film capacitor having high reliability can be obtained.

  In addition, even if defects such as pinholes exist in the capacitor element or the dielectric film, the defective portion can be covered with the synthetic polymer compound A. From this point, a highly reliable molded film A capacitor can be obtained.

  Furthermore, the synthetic polymer compound A has high translucency with respect to ultraviolet rays and visible rays. Therefore, in the capacitor element coating process, when the synthetic polymer compound A is poured into the case or mold and the synthetic polymer compound A is poured in, no bubbles or voids exist before the synthetic polymer compound A is cured. Can be confirmed visually. Therefore, productivity can be remarkably improved.

  According to the third aspect of the present invention, both the flexibility, heat resistance and voltage resistance of the capacitor can be achieved at a good level.

  That is, the first organosilicon polymer is excellent in insulation and heat resistance, but has very poor fluidity and flexibility after curing. Therefore, when the covering is made only of the first organosilicon polymer, the covering cannot be thickened and the voltage resistance cannot be improved. On the other hand, the second organosilicon polymer has fluidity and flexibility. Therefore, the advantage of both polymers can be exhibited by connecting both polymers. By the way, when the weight average molecular weight of a 1st organosilicon polymer is enlarged, heat resistance will improve, but a softness | flexibility will worsen. On the other hand, when the molecular weight of the second organosilicon polymer is increased, the flexibility is improved, but the heat resistance is lowered. That is, by adjusting the weight average molecular weight of each of the first organosilicon polymer and the second organosilicon polymer, the flexibility, heat resistance, and voltage resistance of the synthetic polymer compound A are adjusted to desired levels. can do. In the present invention, since the weight average molecular weight of each of the first organosilicon polymer and the second organosilicon polymer is set to a desired size, both flexibility, heat resistance, and voltage resistance are at good levels. Can be compatible.

  According to the fourth aspect of the invention, since the dielectric constant of the synthetic polymer compound A constituting the dielectric film can be increased, the dielectric constant of the dielectric film can be increased. Therefore, a capacitor having a large capacitance can be obtained. Therefore, when a small capacitance is sufficient, a small and lightweight capacitor can be obtained.

  According to the invention of claim 5, since the thermal conductivity of the synthetic polymer compound A constituting the dielectric film can be increased, the thermal conductivity of the capacitor element can be increased. Therefore, the heat dissipation of the capacitor element can be improved.

  Further, according to the invention described in claim 5, since the thermal conductivity of the synthetic polymer compound A constituting the covering can be increased, the thermal conductivity of the covering can be increased. Therefore, the heat dissipation property of the covering can be improved, and a molded film capacitor excellent in heat dissipation property can be obtained.

  Therefore, according to the fifth aspect of the present invention, an air cooling device or the like can be omitted, the configuration of the capacitor device can be simplified, and the device can be reduced in size and cost. Moreover, since it is excellent in heat resistance and heat dissipation, the rated capacity can be increased by increasing the current density. Therefore, when a small rated capacity is sufficient, a small and lightweight capacitor can be obtained.

  According to invention of Claim 6, the electrostatic capacitance of a film capacitor can be improved reliably.

  According to the seventh aspect of the present invention, the heat dissipation property of the capacitor element or the molded film capacitor can be reliably improved.

  According to the eighth aspect of the invention, the dielectric ceramic fine particles can be effectively filled into the gaps in the three-dimensional structure of the synthetic polymer compound A.

  According to the ninth aspect of the present invention, the insulating ceramic fine particles can be effectively filled in the space between the three-dimensional structures of the synthetic polymer compound A.

  That is, in any ceramic fine particle, if the particle size is too large, the volume filling rate of the fine particles with respect to the synthetic polymer compound A is reduced, and even if the particle size is too small, the fine particles are likely to aggregate with each other. , The volume filling rate decreases. However, if the particle size is as described above, the volume filling rate does not decrease. Therefore, according to invention of Claim 8 or 9, the volume filling factor of 40% vol or more is realizable. When the volume filling factor is 40% vol or more, the proportion of the ceramic fine particles in contact with each other significantly increases, so that high dielectric constant and high thermal conductivity can be obtained.

  According to invention of Claim 10, the dielectric constant of a dielectric film can fully be increased.

  According to the eleventh aspect of the present invention, the thermal conductivity of the covering can be sufficiently increased.

  According to the twelfth aspect of the invention, the volume filling rate of the ceramic fine particles with respect to the synthetic polymer compound A can be set to 50% vol or more.

  In addition, it is preferable that any ceramic fine particles have a shape close to a sphere with few sharp parts. According to this, since the local electric field concentration by fine particles can be avoided, the dielectric strength of the dielectric film or the covering can be improved.

  Further, by filling the dielectric ceramic fine particles as described above, specifically, a high dielectric constant of 3 to 1000 can be realized. Further, by filling the insulating ceramic fine particles as described above, specifically, a high thermal conductivity of 2 to 120 W / mK can be realized.

  Furthermore, since the filled ceramic fine particles do not affect the binding of the synthetic polymer compound A, the heat resistance of the synthetic polymer compound A is not impaired. Further, the ceramic fine particles in the range of the volume filling rate and the shape slightly affect the voltage resistance and viscosity of the synthetic polymer compound A, but hardly cause a problem in practical use. In addition, ceramic fine particles having a volume filling rate and particle size in the above range slightly affect the translucency of the synthetic polymer compound A and the adhesion between the synthetic polymer compound A and the constituent material. Almost no problem.

(First embodiment)
FIG. 1 is a perspective view showing a film capacitor according to a first embodiment of the present invention. The capacitor 50 of this embodiment is a film capacitor having a rated voltage of 1 kV, a rated current of 5 A, and a rated capacity of 10 μF, and is a molded film capacitor in which a capacitor element is covered with a molding material. The capacitor 50 according to this embodiment includes a capacitor element 51 having lead pins 52 and 53 and a covering 54 that covers the capacitor element 51.

  The capacitor element 51 is configured by folding a dielectric film having aluminum electrodes deposited on both sides into a rectangular shape. Specifically, the thickness of the dielectric film is about 6 μm, and the thickness of the aluminum electrode is about 30 nm.

  The lead pins 52 and 53 are attached to both ends of the capacitor element 51 with solder having a melting point of 250 ° C. or higher.

  The covering 54 is made of an epoxy resin using imidazole as a curing agent.

  The external dimensions of the capacitor 50 are a width of 32 mm, a thickness of 16 mm, and a height of 26 mm. The height is a dimension in the direction in which the lead pins 52 and 53 extend.

  In the present embodiment, the dielectric film of the capacitor element 51 is composed of a plurality of third organosilicon polymers formed by linking the first organosilicon polymer and the second organosilicon polymer. Contains molecular compound A.

  In the synthetic polymer compound A, the first organosilicon polymer is polyethylsilsesquioxane having a molecular weight of about 1300. The second organosilicon polymer is polydimethylsiloxane having a molecular weight of about 40,000. The first organosilicon polymer and the second organosilicon polymer are alternately and linearly connected by a siloxane bond to constitute a third organosilicon polymer. The third organosilicon polymer has a molecular weight of about 80,000. The synthetic polymer compound A has a three-dimensional structure formed by connecting a plurality of third organosilicon polymers with an alkylene group.

  Furthermore, in the present embodiment, the epoxy resin constituting the covering 54 and the synthetic polymer compound A constituting the dielectric film are filled with fine particles of insulating ceramics having high thermal conductivity. Aluminum nitride is used as the insulating ceramic. The filled fine particles include two types of fine particles having different particle sizes, that is, fine particles having a particle size of about 2.5 μm and fine particles having a particle size of about 0.07 μm. The volume ratio is included. The particle size ratio between the former and the latter is 7/250. The volume filling rate of the insulating ceramic fine particles with respect to the synthetic polymer compound A is about 63% vol. The volume filling rate of the insulating ceramic fine particles with respect to the epoxy resin is also about 63% vol.

  Therefore, in this embodiment, the synthetic polymer compound A contains the insulating ceramic fine particles. Thereby, the dielectric film has a high thermal conductivity of about 21 W / mK without impairing the voltage resistance. In the present embodiment, the epoxy resin also contains the insulating ceramic fine particles.

  The capacitor 50 having the above configuration exhibited the following characteristics. In the conventional capacitor to be compared, the dielectric film is made of polypropylene, the covering is made of an epoxy resin, the ceramic fine particles are not mixed, and other configurations are the same as those of the capacitor 50.

(1) The withstand voltage at a high temperature of 210 ° C. was about 1600 V or more, and the maximum allowable current was about 1.8 times that of the conventional capacitor.
(2) The insulation resistance was 3000 MΩ or higher at 20 ° C. and DC 500 V, which was higher than that of the conventional capacitor.
(3) The temperature dependency of the capacitance was good. That is, the capacitance was almost independent of temperature up to 200 ° C. Moreover, the change of the electrostatic capacitance in the range of 200 ° C. to 210 ° C. was 1% or less, which was a level causing no practical problem.
(4) The loss factor mainly due to the dielectric loss of the dielectric was 0.13% or less at 20 ° C. and a frequency of 1 kHz, which was favorable. Moreover, a practically sufficient loss rate could be secured even at high temperatures.
(5) Resistant to heat generation due to harmonics and surges, it was able to withstand higher harmonic voltages and surge voltages more than 1.8 times compared to conventional capacitors.
(6) A continuous voltage application test was performed for 3000 hours by applying a voltage 1.5 times the rated voltage. As a result, no significant changes were observed in various characteristics such as capacitance and loss rate.
(7) A moisture resistance test was performed at 80 ° C. and a humidity of 95%. As a result, no abnormality occurred in particular for a long time of 1000 hours or more.
(8) After performing 100 temperature cycle tests in the range of 30 ° C. to 200 ° C., the same moisture resistance test as described above was performed. As a result, there was no abnormality.
(9) Visual inspection was conducted after a long-term continuous electrical charging test and moisture resistance test, but no cloudiness or cracks were observed on the outer periphery.

  As described above, the capacitor 50 of the present embodiment can improve the heat resistance without impairing other characteristics, and has a maximum capacity voltage, maximum capacity current, and harmonics as compared with a conventional capacitor having substantially the same shape. The voltage resistance and surge voltage resistance could be further increased.

(Second Embodiment)
FIG. 2 is a perspective view showing a film capacitor according to a second embodiment of the present invention. The capacitor 60 of the present embodiment is a film capacitor having a rated voltage of 2 kV, a rated current of 10 A, and a rated capacity of 20 μF, and is a molded film capacitor in which a capacitor element is covered with a molding material. The capacitor 60 of the present embodiment includes a capacitor element 61 having lead wires 69 a and 69 b and a covering body 80 that covers the capacitor element 61.

  FIG. 3 is an exploded perspective view of the capacitor element 61. The capacitor element 61 is configured by overlapping a first dielectric film 62 and a second dielectric film 67 and winding them in a cylindrical shape. An aluminum electrode 63 is deposited on the inner surface side of the first dielectric film 62 except for the non-electrode portion 64 having a predetermined width. An aluminum electrode 65 is deposited on the inner surface side of the second dielectric film 67 except for the non-electrode portion 66 having a predetermined width. The non-electrode part 64 and the non-electrode part 66 are located on the opposite sides in the width direction. Electrodes 68 a and 68 b are formed on both end surfaces of the capacitor element 61 by spraying zinc. Lead wires 69a and 69b are connected to the electrodes 68a and 68b, respectively. The non-electrode portions 64 and 66 are for preventing a short circuit when a voltage is applied to the electrodes 68a and 68b.

  And in this embodiment, the 1st and 2nd dielectric films 62 and 67 of the capacitor | condenser element 61 connect two or more 3rd organosilicon polymers which connect a 1st organosilicon polymer and a 2nd organosilicon polymer. 1st synthetic high molecular compound A comprised as mentioned above is contained.

  In the first synthetic polymer compound A, the first organosilicon polymer is polyphenylsilsesquioxane having a molecular weight of about 1500. The second organosilicon polymer is polymethylphenylsiloxane having a molecular weight of about 20,000. The first organosilicon polymer and the second organosilicon polymer are alternately and linearly connected by a siloxane bond to constitute a third organosilicon polymer. The third organosilicon polymer has a molecular weight of about 60,000. The first synthetic polymer compound A has a three-dimensional structure formed by connecting a plurality of third organosilicon polymers with an alkylene group.

  Further, in the present embodiment, the molding material constituting the covering 80 is configured by connecting a plurality of third organosilicon polymers formed by connecting the first organosilicon polymer and the second organosilicon polymer. 2 Synthetic polymer compound A is contained.

  In the second synthetic polymer compound A, the first organosilicon polymer is polymethylphenylsilsesquioxane having a molecular weight of about 3000. The second organosilicon polymer is polydimethylsiloxane having a molecular weight of about 20,000. The first organosilicon polymer and the second organosilicon polymer are alternately and linearly connected by a siloxane bond to constitute a third organosilicon polymer. The third organosilicon polymer has a molecular weight of about 80,000. The second synthetic polymer compound A has a three-dimensional structure constituted by connecting a plurality of third organosilicon polymers with an alkylene group.

  Each of the first and second dielectric films 62 and 67 has a thickness of about 10 μm. Thereby, each film 62 and 67 has high voltage resistance. The dielectric constant of each of the films 62 and 67 is about 2.8, which is equal to or higher than that of this type of general capacitor.

  The capacitor 60 having the above configuration exhibited the following characteristics. In the conventional capacitor to be compared, the dielectric film is made of polypropylene, the covering is made of an epoxy resin, and other configurations are the same as those of the capacitor 60.

(1) The withstand voltage at a high temperature of about 300 ° C. is about 2200 V or higher, and a high maximum allowable voltage at a high temperature that cannot be realized by a conventional capacitor can be realized. The maximum allowable current was also about 1.4 times that of the conventional capacitor.
(2) The insulation resistance was 3000 MΩ or higher at 20 ° C. and DC 2000 V, which was higher than that of the conventional capacitor.
(3) The temperature dependency of the capacitance was good. That is, the capacitance was almost independent of temperature up to 240 ° C. Moreover, the change of the electrostatic capacitance in the range of 240 ° C. to 300 ° C. was 5% or less, which was a level with no practical problem.
(4) The loss factor mainly due to the dielectric loss of the dielectric was 0.15% or less at 20 ° C. and a frequency of 1 kHz, which was favorable. Furthermore, a practically sufficient loss rate could be secured even at high temperatures.
(5) Resistant to heat generated by harmonics and surges, and withstands higher harmonic voltages and surge voltages that are 1.6 times greater than conventional capacitors.
(6) A continuous voltage application test was performed for 3000 hours by applying a voltage 1.5 times the rated voltage. As a result, no significant changes were observed in various characteristics such as capacitance and loss rate.
(7) A moisture resistance test was performed at 80 ° C. and a humidity of 95%. As a result, no abnormality occurred over a long time of 1500 hours or more.
(8) After performing 100 temperature cycle tests in the range of 30 ° C. to 250 ° C., the same moisture resistance test as described above was performed. As a result, there was no abnormality.
(9) Although it was visually inspected after the long-term continuous electrical charging test and moisture resistance test, no occurrence of white turbidity or cracks was observed on the outer periphery or inside of the first and second dielectric films 62 and 67 and the covering 80. It was.
(10) A disassembly inspection was performed to examine the adhesion between the capacitor element 61 and the covering 80. As a result, the adhesion was good and no cracks or voids were observed.

  As described above, the capacitor 60 of the present embodiment can further improve the heat resistance without impairing other characteristics, and has a maximum capacity voltage, maximum capacity current, harmonics as compared with a conventional capacitor having substantially the same shape. The wave voltage tolerance and surge voltage tolerance could be further increased. In this embodiment, the dielectric film and the covering are made of the same kind of synthetic polymer compound A, and therefore have the same kind of material and composition. It is inferred that it contributes to achieving high performance in the continuous voltage test.

(Third embodiment)
The capacitor of this embodiment is different from the capacitor 60 of the second embodiment only in the following points. That is, in the first synthetic polymer compound A constituting the first and second dielectric films 62 and 67, the molecular weight of the second organosilicon polymer is about 40,000, and the molecular weight of the third organosilicon polymer is about 150,000. It is. The first synthetic polymer compound A is filled with fine particles of dielectric ceramics. Therefore, the first synthetic polymer compound A contains dielectric ceramic fine particles.

  As the dielectric ceramic, lead titanate is used.

The capacitor according to the present embodiment exhibited the same characteristics as those of the second embodiment, and particularly the following characteristics.
(1) Since the first and second dielectric films 62 and 67 contain lead titanate, the dielectric constant of the film can be greatly increased.
(2) Since the Curie temperature of lead titanate is high at about 490 ° C., the film can maintain a high dielectric constant even at a high temperature.
(3) The particle size of the lead titanate fine particles is preferably 0.005 to 1 μm, more preferably 0.01 to 0.5 μm. According to this, a film having a uniform dielectric constant can be obtained without impairing the voltage resistance. This is because if the particle size of the fine particles is too large, the withstand voltage of the film is impaired, and if it is too small, the fine particles are aggregated and not uniformly dispersed, making it difficult to form a film having a uniform dielectric constant. Because.
(4) The withstand voltage at a high temperature of about 300 ° C. is about 2200 V or higher, and a high maximum allowable voltage at a high temperature that cannot be realized by a conventional capacitor can be realized.
(5) A practically sufficient loss rate was secured even at high temperatures.
(6) Resistant to heat generated by harmonics and surges, and withstands higher harmonic voltages and surge voltages that are 1.6 times greater than conventional capacitors.
(7) A voltage of 1.5 times the rated voltage was applied and a continuous voltage application test was performed for 3000 hours. As a result, no significant changes were observed in various characteristics such as capacitance and loss rate.

  As described above, the capacitor according to the present embodiment is approximately the same size as the second embodiment, but at the same rating as the rated voltage 2000 V and the rated current 10 A, the rated capacitance is approximately 6 times 120 μF. Could be increased.

(Fourth embodiment)
FIG. 4 is a partially broken perspective view showing a film capacitor according to a fourth embodiment of the present invention. The capacitor 30 of the present embodiment is a film capacitor having a rated voltage of 230 V, a rated current of 80 A, and a rated capacity of 1800 μF. The capacitor 30 of this embodiment is configured by storing a large number of capacitor elements 31 in a metal case 33. The external dimensions of the capacitor 30 are, for example, a width of about 45 cm, a height of about 50 cm, and a depth of about 20 cm.

  In the capacitor 30, for example, ten capacitor elements 31 (three are visible in FIG. 4) are connected in parallel. All capacitor elements 31 are housed in a metal case 33, and between the capacitor element 31 and the metal case 33 is filled with silicon oil that functions as insulating oil. The flash temperature of silicon oil is about 300 ° C., which is about twice as high as that of other insulating oils. Both terminals of the capacitor 30 are connected to external connection terminals 36 and 37 led out by bushings 34 and 35, respectively.

  The capacitor element 31 is configured by winding a dielectric film having aluminum electrodes deposited on both sides in a flat shape. Specifically, the thickness of the dielectric film is about 3 μm, and the thickness of the aluminum electrode is about 20 nm.

  An extraction electrode is formed by spraying zinc alloy on the upper end surface 32 of the capacitor element 31, and a lead wire (not shown) is connected to the extraction electrode by a high melting point solder. The lower end surface of the capacitor element 31 is the same as the upper end surface 32.

  In this embodiment, the dielectric film of the capacitor element 31 is composed of a plurality of third organosilicon polymers formed by connecting the first organosilicon polymer and the second organosilicon polymer. Contains molecular compound A.

  In the synthetic polymer compound A, the first organosilicon polymer is polymethylphenylsilsesquioxane having a molecular weight of about 1300. The second organosilicon polymer is polydimethylsiloxane having a molecular weight of about 20,000. The first organosilicon polymer and the second organosilicon polymer are alternately and linearly connected by a siloxane bond to constitute a third organosilicon polymer. The third organosilicon polymer has a molecular weight of about 60,000. The synthetic polymer compound A has a three-dimensional structure formed by connecting a plurality of third organosilicon polymers with an alkylene group.

The capacitor 30 having the above configuration was manufactured as follows.
First, the lead wires of all the capacitor elements 31 were connected in parallel and connected to the external connection terminals 36 and 37. Next, all the capacitor elements 31 were arranged as shown in FIG. 4 and placed in a container-like metal case 33 together with bushings 34 and 35. Next, the metal case 33 was placed in a vacuum chamber, the atmospheric pressure in the vacuum chamber was lowered, and silicon oil was poured between each capacitor element 31 and the metal case 33. Then, the silicon oil inlet was closed. A mounting bracket 40 was previously attached to the lower part of the metal case 33.

  The capacitor 30 having the above configuration exhibited the following characteristics. In the conventional capacitor to be compared, the dielectric film is made of polypropylene, and other configurations are the same as those of the capacitor 30.

(1) The withstand voltage at a high temperature of 220 ° C. was about 380 V or more. This withstand voltage (maximum allowable voltage) was about 1.6 times the withstand voltage of a conventional capacitor at 120 ° C. Similarly, the maximum allowable current was about 1.5 times.
(2) The insulation resistance was 1600 MΩ or higher at 20 ° C. and DC 100 V, which was sufficiently high. Therefore, practically sufficient insulating properties could be obtained even at high temperatures.
(3) The temperature dependency of the capacitance was good. In other words, the capacitance was almost independent of temperature up to 160 ° C. and increased slightly above 170 ° C. However, the increase was 4% or less even at 220 ° C., which was a level with no practical problem.
(4) The loss factor mainly due to the dielectric loss of the dielectric was 0.14% or less at 20 ° C. and the frequency of 1 kHz, which was favorable. Moreover, a practically sufficient loss rate could be secured even at a high temperature of 220 ° C.
(5) A voltage of 1.5 times the rated voltage was applied, and a long-term continuous power application test for 3000 hours was performed. As a result, no significant changes were observed in various characteristics such as capacitance and loss rate, and high reliability was achieved.

  As described above, the capacitor according to the present embodiment can greatly improve the heat resistance as compared with the conventional capacitor, and the maximum voltage and the maximum current are about 1 as compared with the conventional capacitor having substantially the same shape. .4 to 1.5 times increase.

(Fifth embodiment)
A film capacitor according to a fifth embodiment of the present invention will be described with reference to FIG. The capacitor 30 of the present embodiment and the capacitor 30 of the fourth embodiment are greatly different in the following points. That is, in the capacitor 30 of the fourth embodiment, the capacitor element 31 is housed in the metal case 33 and filled with the insulating oil. However, in the capacitor 30 of this embodiment, the capacitor element 31 is covered with the covering 33 made of a molding material. It is covered with.

  The capacitor of this embodiment is a film capacitor having a rated voltage of 230 V, a rated current of 95 A, a rated capacity of 1800 μF, and a molded film capacitor in which the capacitor element 31 is covered with a molding material. The capacitor 30 according to the present embodiment includes a large number of capacitor elements 31 and a covering 33 that covers all the capacitor elements 31. The external dimensions of the capacitor 30 are, for example, a width of about 45 cm, a height of about 50 cm, and a depth of about 20 cm.

  The capacitor 30 is configured by connecting, for example, ten capacitor elements 31 (three are visible in FIG. 4) in parallel. Both terminals of the capacitor 30 are connected to external connection terminals 36 and 37 led out by bushings 34 and 35, respectively.

  The capacitor element 31 is configured by winding a dielectric film having aluminum electrodes deposited on both sides in a flat shape. Specifically, the thickness of the dielectric film is about 3 μm, and the thickness of the aluminum electrode is about 20 nm.

  An extraction electrode is formed by spraying zinc alloy on the upper end surface 32 of the capacitor element 31, and a lead wire (not shown) is connected to the extraction electrode by a high melting point solder. The lower end surface of the capacitor element 31 is the same as the upper end surface 32.

  In the present embodiment, the dielectric film of the capacitor element 31 is configured by connecting a plurality of third organosilicon polymers formed by connecting the first organosilicon polymer and the second organosilicon polymer. Contains synthetic polymer compound A. Thereby, the heat-resistant temperature as the capacitor | condenser element 31 became 200 degreeC.

  In the first synthetic polymer compound A, the first organosilicon polymer is polymethylphenylsilsesquioxane having a molecular weight of about 600. The second organosilicon polymer is polymethylphenylsiloxane having a molecular weight of about 20,000. The first organosilicon polymer and the second organosilicon polymer are alternately and linearly connected by a siloxane bond to constitute a third organosilicon polymer. The third organosilicon polymer has a molecular weight of about 60,000. The first synthetic polymer compound A has a three-dimensional structure formed by connecting a plurality of third organosilicon polymers with an alkylene group.

  Further, in the present embodiment, the second synthetic polymer compound in which the covering 33 is configured by connecting a plurality of third organosilicon polymers formed by connecting the first organosilicon polymer and the second organosilicon polymer. Contains A.

  In the second synthetic polymer compound A, the first organosilicon polymer is polyphenylsilsesquioxane having a molecular weight of about 2500. The second organosilicon polymer is polymethylphenylsiloxane having a molecular weight of about 15,000. The first organosilicon polymer and the second organosilicon polymer are alternately and linearly connected by a siloxane bond to constitute a third organosilicon polymer. The third organosilicon polymer has a molecular weight of about 70,000. The second synthetic polymer compound A has a three-dimensional structure constituted by connecting a plurality of third organosilicon polymers with an alkylene group.

  Furthermore, in this embodiment, the second synthetic polymer compound A is filled with fine particles of insulating ceramics having high thermal conductivity. Aluminum nitride is used as the insulating ceramic. The filled fine particles include two kinds of fine particles having different particle diameters, that is, fine particles having a particle diameter of about 3 μm and fine particles having a particle diameter of about 0.1 μm, and the former and the latter have a volume of 6: 4. Includes in ratio. The particle size ratio between the former and the latter is 1/30. The volume filling rate of the insulating ceramic fine particles with respect to the second synthetic polymer compound A is about 49% vol.

  Therefore, the second synthetic polymer compound A of the present embodiment contains the insulating ceramic fine particles. Thereby, the second synthetic polymer compound A has a high thermal conductivity of about 9.5 W / mK without impairing the voltage resistance.

The capacitor 30 having the above configuration was manufactured as follows.
First, ten capacitor elements 31 were each coated with the second synthetic polymer compound A. This is called a primary mold. Next, the lead wires of all the capacitor elements 31 were connected in parallel and connected to the external connection terminals 36 and 37. Next, all the capacitor elements 31 were arranged as shown in FIG. 4 and placed in a container-shaped mold (not shown) together with the bushings 34 and 35. Next, the mold was placed in a vacuum chamber, the atmospheric pressure in the vacuum chamber was lowered, and the second synthetic polymer compound A was poured between each capacitor element 31 and the mold and cured by heating. This is called a secondary mold. As described above, all the capacitor elements 31 were covered with the covering 33 having a thickness of 2 to 3 cm as shown in FIG. In addition, the mounting bracket 40 was previously arrange | positioned under the metal mold | die, and the mounting bracket 40 was also fixed to the coating | covering body 33. FIG.

  In the primary mold and the secondary mold, in order to sufficiently impregnate the second synthetic polymer compound A between each capacitor element 31 and the mold, the fact that the viscosity strongly depends on the temperature was used. . That is, the second synthetic polymer compound A was heated at a temperature of about 65 ° C. for 3 hours before curing. As a result, the second synthetic polymer compound A was maintained at a low viscosity of about 4000 to 6000 cp. Then, the second synthetic polymer compound A was cured by heating at 200 ° C.

  Further, if the viscosity of the synthetic polymer compound A is too high, it is difficult to pour so that no gaps or voids are generated between the capacitor element 31 and the mold. Conversely, if the molecular weight of the synthetic polymer compound A is excessively reduced in order to reduce the viscosity, the heat resistance is lowered. However, since the second synthetic polymer compound A has an appropriate molecular weight, it can be poured smoothly without impairing the heat resistance.

  The capacitor 30 having the above configuration exhibited the following characteristics. In the conventional capacitor to be compared, the dielectric film is made of polypropylene, the covering is made of an epoxy resin, and other configurations are the same as those of the capacitor 30.

(1) The withstand voltage at a high temperature of 320 ° C. was about 380 V or more. This withstand voltage (maximum allowable voltage) is about 1.6 times the withstand voltage of a conventional capacitor at 120 ° C. Similarly, the maximum allowable current was about 1.5 times.
(2) The insulation resistance was 2000 MΩ or higher at 20 ° C. and DC 100 V, which was sufficiently high. Therefore, practically sufficient insulating properties could be obtained even at high temperatures.
(3) The temperature dependency of the capacitance was good. In other words, the capacitance was almost independent of temperature up to 130 ° C. and increased slightly above 140 ° C. However, the increase was 5% or less even at 200 ° C., which was a level with no practical problem.
(4) The loss factor mainly due to the dielectric loss of the dielectric was 0.13% or less at 20 ° C. and a frequency of 1 kHz, which was favorable. Moreover, a practically sufficient loss rate could be secured even at high temperatures.
(5) Resistant to heat generated by harmonics and surges, and was able to withstand harmonic voltages and surge voltages about 1.4 times larger than conventional capacitors.
(6) A voltage of 1.5 times the rated voltage was applied, and a long-term continuous power application test for 3000 hours was performed. As a result, no significant changes were observed in various characteristics such as capacitance and loss rate.
(7) A moisture resistance test at 80 ° C. and a humidity of 95% was performed for a long time of 1000 hours or more. As a result, no abnormality occurred. After performing 100 temperature cycle tests in the range of 30 ° C. to 190 ° C., the same moisture resistance test as described above was performed. As a result, there was no abnormality. These are considered to be due to the results of improving the heat resistance and heat dissipation of the capacitor of this embodiment.
(8) The dielectric film and the covering 33 were visually inspected after the long-term continuous voltage application test and the moisture resistance test. As a result, no cloudiness or cracks were found on the outer periphery or inside.
(9) It was examined by disassembling. As a result, the adhesiveness between the capacitor element 31 and the covering 33 was good, and no cracks or voids were observed.

  As described above, the capacitor 30 of the present embodiment can greatly improve the heat resistance as compared with the conventional capacitor, and the maximum voltage, the maximum current, and the harmonics as compared with the conventional capacitor having substantially the same shape. The withstand voltage against the wave voltage and the withstand voltage against the surge voltage could be increased by about 1.4 to 1.5 times.

(Another embodiment)
The present invention is not limited to the first to fifth embodiments, and various modifications can be made as described below.

(1) The first organosilicon polymer constituting the synthetic polymer compound A is polyphenylsilsesquioxane, polymethylsilsesquioxane, polymethylphenylsilsesquioxane, polyethylsilsesquioxane, and polypropylsilsesquioxane. It can be arbitrarily selected from oxane. Moreover, two or more of these may be selected.

(2) The second organosilicon polymer constituting the synthetic polymer compound A can be arbitrarily selected from polydimethylsiloxane, polydiethylsiloxane, polydiphenylsiloxane, and polyphenylmethylsiloxane. Moreover, two or more of these may be selected.

(3) Dielectric ceramic can be selected from potassium niobate, potassium tantalate, sodium tantalate, lithium tantalate, tantalum oxide, barium titanate, titanium oxide, strontium titanate, lead titanate, and barium zirconate. Can be selected.

(4) The insulating ceramic can be arbitrarily selected from aluminum nitride, beryllium oxide, alumina, silicon carbide, diamond, and boron nitride. In particular, insulating ceramics having high thermal conductivity such as diamond and boron nitride may be selected.

(5) The present invention can also be applied to a chip capacitor. For example, when the synthetic polymer compound A is used to coat a chip-type capacitor soldered to a printed board or the like, excessive thermal stress or mechanical stress is applied to the dielectric portion and the main electrodes on both sides. However, the main electrode does not peel off. This is because the synthetic polymer compound A has flexibility even at high temperatures.

(6) The present invention can also be applied to a capacitor housed in a metal case or a mold-sealed capacitor.

(7) The present invention can also be applied to a high-voltage, large-capacity molded film capacitor having a rated capacity of 3.3 kV class or 6.6 kV class and 1 kW to 10 MW.

(8) The synthetic polymer compound A can naturally be used in the envelope of a molded power stationary device.

  Since the present invention can greatly improve the characteristics of the film capacitor such as heat resistance, heat dissipation, and voltage resistance, the utility value is extremely great in the field of film capacitors.

It is a perspective view of the film capacitor of a 1st embodiment of the present invention. It is a perspective view of the film capacitor of 2nd Embodiment of this invention. It is a disassembled perspective view of the capacitor | condenser element of 2nd Embodiment. It is a partially broken perspective view of the film capacitor of the 4th or 5th embodiment of the present invention.

Explanation of symbols

30, 50, 60 Capacitor 31, 51, 61 Capacitor element 33, 54, 80 Cover 62 First dielectric film 67 Second dielectric film

Claims (12)

A high heat-resistant film capacitor having a capacitor element composed of a dielectric film and a conductor,
Synthetic polymer compound A in which the dielectric film is constituted by connecting a plurality of third organosilicon polymers obtained by linking at least one first organosilicon polymer and at least one second organosilicon polymer. Contains
The first organosilicon polymer has a crosslinked structure with a siloxane bond;
The second organosilicon polymer has a linear linked structure with siloxane bonds;
The third organosilicon polymer is constituted by connecting the first organosilicon polymer and the second organosilicon polymer alternately and linearly by siloxane bonds, and has a weight average molecular weight of 20,000 to 800,000. And
A high-heat-resistant film capacitor, wherein the synthetic polymer compound A has a three-dimensional structure formed by connecting a plurality of third organosilicon polymers by covalent bonds generated by an addition reaction. . It has a covering that covers the capacitor element,
The high heat-resistant film capacitor according to claim 1, wherein the covering contains a synthetic polymer compound A. The first organosilicon polymer has a weight average molecular weight of 200 to 70,000;
The second organosilicon polymer has a weight average molecular weight of 5000 to 200,000;
The high heat-resistant film capacitor according to claim 1 or 2, wherein the weight average molecular weight of the first organosilicon polymer is smaller than the weight average molecular weight of the second organosilicon polymer.   The high heat-resistant film capacitor according to claim 1, wherein the synthetic polymer compound A contains dielectric ceramic fine particles having a dielectric constant of 5 or more.   The high heat-resistant film capacitor according to claim 1 or 2, wherein the synthetic polymer compound A contains insulating ceramic fine particles having a thermal conductivity of 4 W / mK or more.   The dielectric ceramic is at least one of potassium niobate, potassium tantalate, sodium tantalate, lithium tantalate, tantalum oxide, barium titanate, titanium oxide, strontium titanate, lead titanate, and barium zirconate. The high heat-resistant film capacitor according to claim 4.   The high heat resistant film capacitor according to claim 5, wherein the insulating ceramic is at least one of aluminum nitride, beryllium oxide, alumina, silicon carbide, diamond, and boron nitride.   The high heat-resistant film capacitor according to claim 4, wherein the dielectric ceramic fine particles have a particle size of 0.005 to 5 μm.   The high heat-resistant film capacitor according to claim 5, wherein the insulating ceramic fine particles have a particle size of 0.01 to 50 μm.   The high heat-resistant film capacitor according to claim 4, wherein a volume filling ratio of the dielectric ceramic fine particles with respect to the synthetic polymer compound A is 10% vol to 80% vol.   The high heat-resistant film capacitor according to claim 5, wherein a volume filling rate of the insulating ceramic fine particles with respect to the synthetic polymer compound A is 15% vol to 85% vol. The high particle according to claim 4 or 5, wherein the fine particles include a plurality of types of fine particles having different particle sizes, and a particle size ratio of the fine particles is in a range of 1: 1/10 to 1: 1/200. Heat resistant film capacitor.

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