JP2017098495A - Film capacitor, coupled capacitor, inverter using them, and electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film capacitor having a long life with reduced equivalent series resistance (ESR), a coupled capacitor, and an inverter using them, and an electric vehicle.SOLUTION: The film capacitor includes: a main body 6 in which a dielectric film 1 and a metal film 3 are wound; and a pair of external electrodes 7 provided on opposed end faces of the main body 6. The metal film 3 has first portions 3c and second portions 3d having different thicknesses disposed alternately and continuously in the circumferential direction of winding. The first portions 3c and the second portions 3d are opposed to each other with the dielectric film 1 interposed therebetween.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a film capacitor, a coupled capacitor, an inverter using the same, and an electric vehicle.

  The film capacitor has, for example, a metal film formed by vapor deposition on the surface of a dielectric film obtained by filming a polypropylene resin as an electrode. With such a configuration, even when a short-circuit occurs in the insulation defect portion of the dielectric film, the metal film around the defect portion is evaporated and scattered by the short-circuit energy to insulate and prevent insulation breakdown of the film capacitor ( Self-healing) (see, for example, Patent Document 1).

  For this reason, it has been noted that film capacitors can prevent ignition and electric shock when an electric circuit is short-circuited. Recently, application to power supply circuits such as LED (Light Emitting Diode) lighting has started, and Applications are expanding to motor drive and photovoltaic power generation inverter systems (see, for example, Patent Document 2).

  In a film capacitor, a vapor deposition film is generally used as a metal film. However, since the thickness is as thin as 1 to 100 nm, there is a problem that the sheet resistance is large and the equivalent series resistance (ESR) is large, so that ESR is reduced. If the sheet resistance is reduced simply by increasing the film thickness, there is a concern that the self-recovering property is impaired. In Patent Document 3, in a film capacitor having metallicon electrodes on both ends of a main body obtained by winding or laminating a dielectric film on which a metal film is deposited, as shown in FIG. It is disclosed that the ESR can be reduced by dividing the insulating slit 107 provided in the central portion into divided electrodes (103a, 103b) and thickening the divided electrode (103a) on the metallicon electrode connection side.

JP 9-129475 A JP 2010-178571 A JP 2000-012368 A

  However, in the film capacitor described in Patent Document 3, wrinkles are likely to occur in the winding direction because portions (insulating slits) where there is no vapor deposition electrode are concentrated at the center in the width direction. Such a film capacitor has a problem that when a high voltage is applied, breakage occurs along the wrinkles, and the electrostatic capacity is likely to be greatly reduced, and the life of the film capacitor is shortened.

  An object of the present invention is to provide a film capacitor, a coupled capacitor, an inverter using the same, and an electric vehicle that have a reduced equivalent series resistance (ESR) and have a long lifetime.

The film capacitor of the present invention includes a main body in which a dielectric film and a metal film are wound, and a pair of external electrodes provided on opposite end surfaces of the main body, and the metal film has a winding circumference. The first portion and the second portion, which are alternately arranged continuously in the direction and have different thicknesses, are opposed to each other with the dielectric film interposed therebetween. .

  The connection type capacitor of the present invention is a connection type capacitor comprising a plurality of film capacitors and a bus bar connecting the plurality of film capacitors, wherein the film capacitor is the film capacitor described above.

  The inverter of the present invention is an inverter including a bridge circuit constituted by a switching element and a capacitor connected to the bridge circuit, and the capacitor is the film capacitor or the connected capacitor.

  An electric vehicle according to the present invention is an electric vehicle including a power source, an inverter connected to the power source, a motor connected to the inverter, and wheels driven by the motor. It is an inverter.

  ADVANTAGE OF THE INVENTION According to this invention, an equivalent series resistance (ESR) is reduced and a long-life film capacitor, a connection type | mold capacitor, an inverter using this, and an electric vehicle can be provided.

It is the expansion | deployment perspective view which showed the structure of the film capacitor typically. It is a top view which shows a part of surface of a metallized film. It is the XX sectional view taken on the line of FIG. 1 which shows the laminated structure of a dielectric film and a metal film. (A) is a top view which shows a part of surface of the metallized film which has a division | segmentation electrode, (b) is sectional drawing of the site | part which has a division | segmentation electrode. The lamination | stacking state of the dielectric film and metal film of double-sided vapor deposition is shown, (a) is the XX sectional view taken on the line of FIG. 1, (b) is the YY sectional view taken on the line of FIG. The lamination | stacking state of the dielectric film and metal film of single-sided vapor deposition is shown, (a) is the XX sectional view taken on the line of FIG. 1, (b) is the YY sectional view taken on the line of FIG. It is the perspective view which showed the structure of the connection type capacitor typically. It is a schematic block diagram for demonstrating the structure of one Embodiment of an inverter. It is a schematic structure figure showing one embodiment of an electric vehicle. The dielectric film and metal film of the conventional film capacitor are shown, (a) is sectional drawing which shows a lamination state, (b) is a top view which shows a part of surface of a metallization film.

  A film capacitor A shown in FIG. 1 includes a dielectric film 1a, a metal film 3a, a dielectric film 1b, and a metal film 3b, which are stacked in this order. Metallicon electrodes are provided. In FIG. 1, in order to facilitate understanding, the drawn dielectric films 1a and 1b and the metal films 3a and 3b are drawn so that they are thicker toward the front of the page.

  In FIG. 1, the width direction of the dielectric films 1a and 1b and the metal films 3a and 3b is shown as the x direction, the length direction as the y direction, and the thickness direction as the z direction.

For example, metal films 3a and 3b are provided on the main surfaces of the dielectric films 1a and 1b, respectively, to form metallized films 5a and 5b. In this case, the metal films 3a and 3b are portions where the metal films 3a and 3b that are exposed portions of the dielectric films 1a and 1b are not formed on one end side in the width direction (x direction) of the dielectric films 1a and 1b. (Hereinafter, they may be referred to as metal film non-forming portions 10a and 10b.) Are formed so as to remain continuously in the length direction (y direction).

  The metallized films 5a and 5b are arranged so that the metal film non-forming portions 10a and 10b are positioned in opposite directions in the width direction (x direction) of the dielectric films 1a and 1b, and the metal films 3a and 3b are shifted. Overlaid in state.

  That is, in the film capacitor A, as shown in FIG. 1, the metallized film 5a composed of the dielectric film 1a and the metal film 3a and the metallized film 5b composed of the dielectric film 1b and the metal film 3b are as shown in FIG. It is piled up and wound.

  The metal films 3a and 3b are connected to the external electrodes 7a and 7b, respectively, at the connection portions exposed at different end faces of the main body portion 6.

  In this embodiment, as shown in FIG. 2, the metal film 3 has a first part 3c and a second part 3d having different thicknesses, and the first part 3c and the second part 3d are (dielectrics). The film 1 is alternately and continuously arranged in the wound length direction (y direction). Here, the thicker one is the first part 3c and the thinner one is the second part 3d. By using the metallized film 5 provided with such a metal film 3 and winding, the main body 6 has a first part 3c and a second part 3d sandwiching the dielectric film 1 as shown in FIG. Are opposite to each other.

  Here, in the region where one main surface is in contact with the first portion 3c, the other main surface is in contact with the second portion 3d, and in the region where one main surface is in contact with the second portion 3d, the dielectric film 1 Is in contact with the first portion 3c. That is, the dielectric film 1 is in contact with the second portion 3d of the metal film 3 on the back side (the other main surface) of the region where one main surface is in contact with the first portion 3c of the metal film 3, and the one main surface is metal. The back side (the other main surface) of the region in contact with the second part 3d of the film 3 is in contact with the first part 3c of the metal film 3.

  In other words, the dielectric film 1 is sandwiched between the first part 3c and the second part 3d which are a pair of parts of the metal film 3 having different thicknesses.

  In such a film capacitor A, the thicknesses of the first part 3c and the second part 3d, which are a pair of parts of the metal film 3 sandwiching the dielectric film 1, are different from each other, so ESR can be reduced while maintaining (voltage). That is, self-recovery, that is, withstand voltage is maintained by the second portion 3d having a small thickness and high sheet resistance, and ESR is reduced by the first portion 3c having a large thickness and low sheet resistance.

  Here, the 1st site | part 3c and 2nd site | part 3d from which thickness differs are alternately arrange | positioned in the length direction (y direction) wound. When an area where the metal film 3 is opposed to the dielectric film 1 is an effective area, the first part 3c and the second part 2d are provided from one end to the other end in the width direction of the effective area. ing. Thus, by making the thickness of the metal film 3 uniform in the width direction (x direction) of the range of the effective region, compared with the case where the divided electrodes having different thicknesses are arranged side by side in the width direction, Wrinkles along the turning direction (y direction) are less likely to occur, and the life of the film capacitor A is improved. In addition, the second portion 3d and the low resistance first portion 3c are alternately adjacent to each other, so that current is easily diffused from the high resistance second portion 3d to the low resistance first portion 3c, thereby suppressing heat generation. There is also an advantage of being able to.

As shown in FIGS. 4A and 4B, the second portion 3d of the metal film 3 includes a plurality of divided electrodes 3di divided by a mesh-like insulating slit provided intermittently, and a space between the divided electrodes. It is preferable that the fuse portion is connected. The divided electrode 3di and the fuse portion divided by the insulating slit can be formed by laser processing.

  By dispersing the fuse portions in this way, it is possible to suppress the concentration of heat generation and to reduce the concern that the fuse portions are disconnected simultaneously across a plurality of layers. In addition, there is an advantage that components evaporated by self-recovery are easily evaporated to the outside through a mesh-like insulating slit.

  On the other hand, the first part 3c of the metal film 3 is preferably provided continuously from one end in the width direction of the effective region to the other end in order to reduce ESR.

  When the thickness of the first part 3c is T1 and the thickness of the second part 3d is T2, the ratio of T1 and T2 (T1 / T2) is preferably in the range of 2.0 to 8.0. By setting the ratio of T1 and T2 in such a range, an ESR reduction effect by the first portion 3c can be obtained, and an increase in the volume of the film capacitor A can be suppressed.

  The thickness T2 of the second portion 3d is preferably, for example, 20 nm or less, particularly 5 to 15 nm. By making the 2nd site | part 3d into such thickness, sheet resistance (sheet resistance) will be 18-50 ohms / square, and self-healing property can be exhibited. On the other hand, the thickness T1 of the first portion 3c is preferably 2 to 4 times T2, that is, in the range of 10 to 80 nm. However, T1 is set to be twice or more of T2.

  The lengths in the y direction of the first part 3c and the second part 3d are equal. When the length in the y direction of the first part 3c and the second part 3d is W and the length of the circumference (one round) of the wound dielectric film 1 is L, W is the length of the wound circumference. Preferably it is equal to the length L. That is, it is preferable to change W according to the radius around which the dielectric film 1 is wound. As a result, in the wound film capacitor A, the dielectric film 1 is sandwiched between the first part 3c and the second part 3d, and ESR can be reduced while maintaining self-recovery, that is, withstand voltage. . W may be an integer multiple of L, or L may be an integer multiple of W.

  Further, the metal film 3 (3a, 3b) has a resistance of the metal film 3 against the effective region where the metal films 3a, 3b overlap in the vicinity (3e) of the connection portion with the external electrode 7 (7a, 7b). It is preferable to have a lowered heavy edge structure (hereinafter, the vicinity 3e of the connection portion of the metal film 3 with the external electrode 7 may be referred to as a heavy edge portion 3e). The thickness (T3) of the metal film 3 in the vicinity 3e of the connection with the external electrode 7 is preferably equal to the thickness T1 of the first portion 3c. By making the thickness T3 of the metal film 3 in the connection portion vicinity 3e equal to the thickness T1 of the first portion 3c, wrinkles are less likely to occur, and the life of the film capacitor A can be further improved.

  Moreover, as shown in FIG. 3, it is preferable that the 1st site | part 3c is thin in the vicinity of the metal film non-formation part 10 (exposed part of the dielectric film 1). With such a configuration, self-recovery can be exhibited when dielectric breakdown occurs in the heavy edge portion 3e of the second portion 3d.

  5A is a cross-sectional view taken along line YY in FIG. 2, and FIG. 5B is a cross-sectional view taken along line XX in FIG. For example, as shown in FIGS. 5A and 5B, the film capacitor A includes a metallized film 5 (double-sided vapor-deposited film) in which metal films 3 are formed on both main surfaces of the dielectric film 1 by vapor deposition, for example, It is obtained by overlapping and winding the dielectric film 1 on which no film is formed.

As the metallized film 5 having the metal film 3 on both main surfaces, the second part 3d of the metal film 3 is formed on the other main surface of the region where the first part 3c of the metal film 3 is provided on one main surface. The one provided with the first portion 3c of the metal film 3 is used for the other main surface of the region where the second portion 3d of the metal film 3 is provided on one main surface (FIG. 5A). By winding the metallized film 5 and the dielectric film 1 on which the metal film is not formed, the film capacitor A of this embodiment can be obtained.

  Further, for example, metal films 3a and 3b are formed on one main surface of the dielectric film 1 by vapor deposition, for example, and metallized films 5a and 5b (single-side vapor deposition films) on which the metal film is not formed on the other main surface. The surface of the metallized film 5a having the metal film 3a and the surface of the metallized film 5b that are not formed with the metal film face each other, the surface of the metallized film 5a that is not formed with the metal film, and the metallized film 5b. It can also be obtained by overlapping and winding so that the surface having the metal film 3b faces each other (see FIGS. 6A and 6B).

  At this time, the first part 3c of the metallized film 5a and the second part 3d of the metallized film 5b face each other with the dielectric film 1 in between, and the second part 3d of the metallized film 5a and the metallized film The film capacitor A of the present embodiment is obtained by winding and winding the 5b first portion 3c so as to face the dielectric film 1 (FIG. 6A).

  In addition, in the cross-sectional views of FIGS. 3 to 6, the thickness direction (z direction) of the film is shown in an enlarged manner for easy explanation.

  Examples of the insulating resin material used for the dielectric film 1 include polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyethylene naphthalate (PEN), polyarylate (PAR), and polyphenylene ether (PPE). ), Polyetherimide (PEI), and cycloolefin polymer (COP). Polyarylate (PAR) is particularly preferable because of its high dielectric breakdown voltage.

  Such a film capacitor may be produced, for example, as follows. First, the dielectric film 1 is prepared. The dielectric film 1 is obtained, for example, by forming a resin solution in which an insulating resin is dissolved in a solvent into a sheet shape on a surface of a base material made of, for example, polyethylene terephthalate (PET), and drying to volatilize the solvent. It is done. The forming method may be appropriately selected from known film forming methods such as a doctor blade method, a die coater method, and a knife coater method. Solvents used for molding include, for example, methanol, isopropanol, n-butanol, ethylene glycol, ethylene glycol monopropyl ether, methyl ethyl ketone, methyl isobutyl ketone, xylene, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, dimethylacetamide, cyclohexane Alternatively, an organic solvent containing a mixture of two or more selected from these may be used. Further, a resin film produced by a melt extrusion method may be stretched.

  The thickness of the dielectric film 1 may be, for example, 5 μm or less, but it is particularly preferable to use the dielectric film 1 having a thickness of 0.5 to 4 μm.

  The dielectric film 1 may be made of only the above-described insulating resin, but may contain other materials. Examples of components other than the resin contained in the dielectric film 1 include the above-described organic solvents and inorganic fillers. As the inorganic filler, for example, inorganic oxides such as alumina, titanium oxide, and silicon dioxide, inorganic nitrides such as silicon nitride, glass, and the like can be used. In particular, when a material having a high relative dielectric constant such as a composite oxide having a perovskite structure is used as the inorganic filler, the relative dielectric constant of the entire dielectric film 1 is improved, and the film capacitor can be reduced in size. In order to improve the compatibility between the inorganic filler and the resin, the inorganic filler may be subjected to a surface treatment such as a silane coupling treatment or a titanate coupling treatment.

  When such an inorganic filler is used for the dielectric film 1, a composite film containing less than 50% by mass of the inorganic filler and 50% by mass or more of the resin is used to maintain the flexibility of the resin. Effects such as improvement of relative dielectric constant can be obtained. Moreover, it is preferable that the size (average particle diameter) of an inorganic filler shall be 4-1000 nm.

  After masking one end of the width direction on the main surface of the produced dielectric film 1, a metal component such as aluminum (Al) is deposited to form a metallized film 5.

  The metal film 3 having the first part 3c and the second part 3d is formed as follows. A mask (oil mask) is applied by applying oil to a region where the second portion 3d of one main surface of the dielectric film 1 is formed. The first deposition is performed on the dielectric film 1 with an oil mask using a resistance heating type vacuum deposition apparatus. At this time, the oil mask is volatilized, and further vapor deposition is performed, whereby a vapor deposition film is formed also in the region where the oil mask is volatilized, and the metal film 3 having the first part 3c and the second part 3d is provided. A metallized film 5 is obtained.

  When the metal film 3 having the first part 3c and the second part 3d is formed on both main surfaces of the dielectric film 1, the first part 3c and the second part 3d are first formed on one main surface by the above method. The metal film 3 is formed. Then, a mask is applied to the other end portion in the width direction of the other main surface (an end portion different from the one masked with the one main surface), and the third evaporation is performed on the other main surface. The first part 3c and the second part 3d of the metal film 3 provided on one main surface are discriminated by image processing, and an oil mask is provided on the other main surface of the region where the first part 3c is formed on one main surface. Apply. Further, by performing the fourth vapor deposition on the other main surface subjected to the oil mask, the metal film 3 is provided on both main surfaces, and the dielectric film 1 is sandwiched between the first portion 3c and the second portion 3d. A metallized film 5 is obtained.

  The metallized film 5 having the metal film 3 on both main surfaces is rolled up with the dielectric film 1 not having the metal film 3 to obtain the main body 6.

  The metallized film 5 (5a, 5b) having the metal film 3 (3a, 3b) only on one main surface has two sheets as one set, and the first portion 3c of the one metal film 3 and the other are processed by image processing. The main body 6 is obtained by winding the metal film 3 so that the second portion 3d of the metal film 3 overlaps.

  A film capacitor A is obtained by forming a metallicon electrode as the external electrode 7 on both end faces of the obtained main body 6. For the formation of the external electrode 7, for example, metal spraying, sputtering, plating, or the like is suitable.

  Subsequently, the film capacitor A of this embodiment is obtained by covering the surface of the main body 6 on which the external electrode 7 is formed with an exterior member (not shown).

  Examples of the material of the metal film 3 include metals and alloys such as aluminum (Al) and zinc (Zn). The thickness of the metal film 3 is preferably 5 to 100 nm, particularly 10 to 80 nm.

  Further, as the material of the metallicon electrode, at least one metal material selected from zinc, aluminum, copper and solder is suitable.

FIG. 7 is a perspective view schematically showing the configuration of one embodiment of a coupled capacitor. In FIG. 7, in order to make the configuration easy to understand, the case and the resin for molding are omitted. The coupled capacitor C of this embodiment has a configuration in which a plurality of film capacitors A are connected in parallel by a pair of bus bars 21 and 23. Bus bars 21 and 23
It is composed of terminal portions 21a and 23a for external connection and lead terminal portions 21b and 23b connected to the external electrodes 7a and 7b of the film capacitor A, respectively.

  When the film capacitor A described above is applied to the connection type capacitor C, the equivalent series resistance (ESR) is reduced, and the connection type capacitor C having a long life can be obtained.

  The connected capacitor C has a plurality of film capacitors A (four in the present embodiment) arranged, and is connected to external electrodes 7a and 7b formed on both ends of the main body 6 via a bonding material. , 23 can be obtained.

  The film capacitor A and the connected capacitor C can be made into a resin mold type (case mold type) capacitor after being accommodated in the case and filled with a resin in the gap in the case.

  7 is arranged in the direction of the major axis of the cross section of the film capacitor A. In addition, the connected capacitor C has a structure in which the film capacitor A is stacked in the direction of the minor axis of the cross section. However, the same effect can be obtained.

FIG. 8 is a schematic configuration diagram for explaining the configuration of an embodiment of the inverter. FIG. 8 shows an example of an inverter D that generates alternating current from direct current. As shown in FIG. 8, the inverter D of the present embodiment includes a bridge circuit 31 composed of a switching element (for example, an IGBT (Insulated Gate Bipolar Transistor)) and a diode, and an input of the bridge circuit 31 for voltage stabilization. It has a configuration including a capacitor 33 disposed between the terminals. Here, the film capacitor A or the connected capacitor C is applied as the capacitor 33.

  The inverter D is connected to a booster circuit 35 that boosts the voltage of the DC power supply. On the other hand, the bridge circuit 31 is connected to a motor generator (motor M) serving as a drive source.

  FIG. 9 is a schematic configuration diagram showing an embodiment of an electric vehicle. FIG. 9 shows an example of a hybrid vehicle (HEV) as the electric vehicle E.

  9, reference numeral 41 denotes a driving motor, 43 denotes an engine, 45 denotes a transmission, 47 denotes an inverter, 49 denotes a power source (battery), and 51a and 51b denote front wheels and rear wheels.

  This electric vehicle E mainly has a function of transmitting the output of the motor 41 or the engine 43 as a drive source, or both to the pair of left and right front wheels 51a via the transmission 45, and the power source 49 is connected to the motor via the inverter 47. 41.

  Further, the electric vehicle E shown in FIG. 9 is provided with a vehicle ECU 53 that performs overall control of the entire electric vehicle E. The vehicle ECU 53 receives a drive signal corresponding to the operation of the driver or the like from the electric vehicle E such as an ignition key 55, an accelerator pedal (not shown), and a brake. The vehicle ECU 53 outputs an instruction signal to the engine ECU 57, the power source 49, and the inverter 47 as a load based on the drive signal. The engine ECU 57 controls the rotational speed of the engine 43 in response to the instruction signal and drives the electric vehicle E.

When the inverter D to which the film capacitor A or the connected capacitor C of the present embodiment is applied as the capacity unit 33 is mounted on an electric vehicle E as shown in FIG. 9, for example, the film capacitor A or the connected capacitor C is equivalent in series. Since the resistance (ESR) is reduced and the lifetime is long, switching noise generated in the inverter 47 and the like can be reduced for a long period of time.

  In addition, the inverter D of this embodiment can be applied not only to the hybrid vehicle (HEV) described above but also to various power conversion application products such as an electric vehicle (EV), a fuel cell vehicle, an electric bicycle, a generator, and a solar cell. .

  A dielectric film having an average thickness of 3 μm was prepared using polyarylate (U-100, manufactured by Unitika). The dielectric film was prepared by dissolving polyarylate in toluene, applying the solution onto a polyethylene terephthalate (PET) substrate using a coater, and forming the sheet. After molding, heat treatment was performed at 130 ° C. to remove toluene, and a dielectric film was obtained.

  The obtained dielectric film was peeled off from the substrate, slitted to a width of 130 mm, and then a 97 mm wide Al metal film was vacuum deposited on one or both main surfaces of the dielectric film as an electrode film using a metal mask. Formed by the method.

  Vacuum deposition of the metal film was performed using a resistance heating type vacuum deposition apparatus. Sample No. In 1-3, the thickness of the vapor deposition film was adjusted using the oil mask, and it was set as the metallized film which has a metal film of a structure as shown in Table 1. Sample No. 2 is a metallized film in which a metal film is provided on both principal surfaces of the dielectric film, and the other samples are metallized films in which a metal film is provided only on one side of the dielectric film.

  The thickness of the metal film was obtained by observation with a scanning electron microscope (SEM) of a cross section subjected to ion milling. Sheet resistance was evaluated in a 4-terminal resistance measurement mode using a multimeter. Table 1 shows the thickness of the metal film and the sheet resistance. Sample No. For convenience, Table 1 shows the thick part of the metal film as the first part and the thin part as the second part for convenience.

  The 130 mm wide metallized film was further slit to obtain a 50 mm wide metallized film having a 1.5 mm margin (a non-metal film-formed part where the dielectric film was exposed).

  As a winding core, a polypropylene (PP) cylinder having an outer diameter of 5 mm and a length of 50 mm was used. A pair of metallized films having a width of 50 mm or a metallized film and a dielectric film were overlapped so that the metal films were opposed to each other with the dielectric film interposed therebetween, and wound around a core to prepare a wound body. The pair of metallized films are wound in a state where they are shifted from each other by 0.5 mm in the width direction (x direction), and the margin portions are arranged on different sides in the width direction (x direction). Obtained. The number of wrinkles was 450.

  Sample No. In the metal films 1 and 2, W is 15.7 mm at the center (start of winding) of the wound body and 37.7 mm at the outer periphery (end of winding) so that W gradually increases from the center to the outer periphery. Formed. Sample No. When winding 1, the first metallized film and the second metallized film were overlapped and wound so that the first part of the metallized film overlapped with the second part of the other metallized film. Sample No. In the second part 2, a mesh-like insulating slit was intermittently formed by laser processing to form a fuse part having a width of 0.4 mm connecting between the 2 mm × 2 mm divided electrodes.

  An alloy of zinc and tin was sprayed on the opposing end face where the electrode film of the wound body was exposed to form a metallicon electrode as a terminal electrode to obtain a film capacitor.

The capacitance, dielectric loss (tan δ), withstand voltage, and lifetime of the produced film capacitor were measured. Capacitance and dielectric loss (tan δ) were measured using an LCR meter under conditions of AC 10 V and 1 kHz. The equivalent series resistance (ESR) was calculated from the measurement results of capacitance and dielectric loss (tan δ).

  The withstand voltage was a voltage when a DC voltage was applied to the film capacitor at a boosting rate of 0 V to 10 V per second using an insulation resistance meter, and the leakage current reached 0.01 A. The breakdown electric field strength (BDE, V / μm) was calculated from the measured withstand voltage and the thickness of the dielectric film.

  The lifetime was defined as the time immediately before the capacitance decreased by 5% or more from the initial value by continuously applying a DC voltage of 400 V / μm at 105 ° C. and measuring the capacitance every 10 hours.

  Sample No. Nos. 1 and 2 showed excellent characteristics such as low ESR and a lifetime of 500 hours or more. On the other hand, sample No. No. 3 had a short lifetime of less than 400 hours, and fracture occurred in the wrinkle portion that occurred near the center in the width direction (x direction) during winding. Sample No. No. 4 has a large ESR. In No. 5, the sheet resistance was too low, so that the self-healing function was not exhibited, and the breakdown electric field strength (BDE) was low.

A, B ... Film capacitor C ... Linked capacitor D ... Inverter E ... Electric vehicle 1, 1 a, 1 b... Dielectric film 3, 3 a, 3 b... Metal film 3 c. -Metal film second part 3e ... Metal film heavy edge parts 5, 5a, 5b ... Metallized film 6 ... Body part 7, 7a, 7b ... External electrodes 21, 23 ... Bus bar 31 ... Bridge circuit 33 ... Capacitor 35 ... ... Booster circuit 41 ... Motor 43 ... Engine 45 ... Transmission 47 ... Invar Motor 49 ......... supply 51a ········ front 51b ········ rear wheel 53 ......... vehicle ECU
55 ... Ignition key 57 ... Engine ECU

Claims (11)

A main body portion in which a dielectric film and a metal film are wound, and a pair of external electrodes provided on opposite end surfaces of the main body portion,
The metal film has a first part and a second part, which are alternately and continuously arranged in the circumferential direction of winding, and have different thicknesses,
The film capacitor, wherein the first part and the second part are opposed to each other with the dielectric film interposed therebetween.   When an area where the metal film is opposed to the dielectric film is an effective area, the first part and the second part are provided from one end to the other end in the width direction of the effective area. The film capacitor according to claim 1, wherein the film capacitor is formed.   3. The first portion according to claim 2, wherein the first portion is thicker than the second portion, and is continuous from the one end portion in the width direction of the effective region to the other end portion. The film capacitor as described.   The second portion is thinner than the first portion, and includes a plurality of divided electrodes divided by a mesh-like insulating slit provided intermittently, and a fuse portion connecting the divided electrodes. The film capacitor according to claim 1, wherein the film capacitor is formed.   The ratio (T1 / T2) of T1 to T2 is 2.0 to 8.0, where T1 is the thickness of the first portion and T2 is the thickness of the second portion. Item 5. The film capacitor according to any one of Items 1 to 4.   The said main-body part is comprised by the metallized film which comprises the said metal film in the both main surfaces of the said dielectric film, and the said dielectric film which does not comprise a metal film, The 1-5 characterized by the above-mentioned. A film capacitor according to any one of the above. The main body is constituted by first and second metallized films provided with the metal film on one main surface of the dielectric film,
The first metallized film and the second metallized film include the one main surface including the metal film of one of the metallized films and the metal film of the other metallized film. The other main surface that is not in contact with each other, and the first portion and the second portion are disposed so as to face each other with the dielectric film interposed therebetween. The film capacitor as described.   A connected capacitor comprising a plurality of film capacitors and a bus bar connecting the plurality of film capacitors, wherein the film capacitor is the film capacitor according to any one of claims 1 to 7. A connected capacitor.   It is an inverter provided with the bridge circuit comprised by a switching element, and the capacity | capacitance part connected to this bridge circuit, Comprising: The said capacity | capacitance part is a film capacitor in any one of Claims 1-7. A featured inverter.   An inverter comprising a bridge circuit constituted by a switching element and a capacitor connected to the bridge circuit, wherein the capacitor is the coupled capacitor according to claim 8. .   An electric vehicle comprising: a power supply; the inverter according to claim 9 or 10 connected to the power supply; a motor connected to the inverter; and a wheel driven by the motor. .

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