Film capacitor

Abstract

To provide a film capacitor which is manufactured with good workability without using special equipment, has high heat dissipation at the center of a capacitor element, and has a metallized film wound uniformly.SOLUTION: Film capacitor 1 includes capacitor element 10. The capacitor element 10 has a wound body 6 and a pair of end surface electrodes 7 provided on both end surfaces of the wound body 6. The wound body 6 includes the core 20 around which the preceding wound film 2 is wound, and the metallized film 5 that includes the dielectric film 3 and the metal film 4 provided on the dielectric film 3 and is wound around the core 20. The leading film 2 includes an electrically insulating film 8 and a thermally conductive film 9 provided on the film 8.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates generally to film capacitors, and more particularly to a film capacitor having a capacitor element. [Background technology]

[0002] Patent Document 1 discloses a metallized film capacitor. This metallized film capacitor comprises an element in which a pair of metallized films, each having a dielectric film on which a vapor-deposited metal electrode is formed, are wound so that the vapor-deposited metal electrodes face each other via the dielectric film, and metallikon electrodes formed by metal spraying on both end surfaces of the element. Two winding cores formed by winding metal foil are coaxially arranged with a gap between them in a non-contact state, and the pair of metallized films are wound around the two winding cores, with one end of each of the two winding cores connected to the metallikon electrode.

[0003] Patent Documents 2 and 3 also disclose metallized film capacitors similar to those in Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-211128 [Patent Document 2] International Publication No. 2013 / 073110 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-211326 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the metallized film capacitors of Patent Documents 1 to 3 have the following problems.

[0006] First, in Patent Documents 1 to 3, there is a risk that workability may be impaired when manufacturing a metallized film capacitor. That is, because two winding cores are used for one metallized film capacitor, when manufacturing a metallized film capacitor, the two winding cores must be arranged coaxially and non-contact with a predetermined gap between them. This work is time-consuming, and there is a risk that workability and winding accuracy may be impaired.

[0007] Furthermore, in Patent Documents 1 to 3, there is a risk that the heat dissipation at the center of the metallized film capacitor will be insufficient. As described above, when two winding cores are arranged in a non-contact state with a predetermined gap therebetween, it is inevitable that there will be an error in the predetermined gap. The main reason for providing the predetermined gap is to prevent short circuits, so the tolerance is set so that the predetermined gap is wider. As a result, there is a risk that the heat dissipation at the center of the metallized film capacitor will be insufficient.

[0008] Furthermore, in Patent Documents 1 to 3, there is a risk that the metallized film will not be wound evenly. As described above, a predetermined gap is provided between the two winding cores. As such, a step is created between the two winding cores and the gap, and when the metallized film is wound across the two winding cores, the step is likely to cause wrinkles in the metallized film. As a result, there is a risk that the metallized film will not be wound evenly.

[0009] An object of the present disclosure is to provide a film capacitor that can be manufactured with good workability without using special equipment, has high heat dissipation properties at the center of the capacitor element, and is uniformly wound with a metallized film. [Means for solving the problem]

[0010] A film capacitor according to one aspect of the present disclosure includes a capacitor element. The capacitor element includes a wound body and a pair of end electrodes provided on both end surfaces of the wound body. The wound body includes a winding core around which a pre-wound film is wound, a dielectric film, and a metal film provided on the dielectric film, and a metallized film wound around the winding core. The pre-wound film includes an electrically insulating film and a thermally conductive film provided on the film. [Effects of the Invention]

[0011] According to the present disclosure, the film capacitor can be manufactured with good workability without using special equipment, the heat dissipation properties of the center of the capacitor element of the film capacitor are high, and the metallized film is wound uniformly in the film capacitor. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic perspective view showing a film capacitor according to a first embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view of the wound body before being flattened, taken along a plane parallel to the axial direction. [Figure 3] FIG. 3 is a schematic cross-sectional view of the wound body before being flattened, taken along a plane perpendicular to the axial direction. [Figure 4] FIG. 4 is a schematic cross-sectional view of the rolled body after flattening, taken along a plane parallel to the axial direction. [Figure 5] FIG. 5 is a schematic cross-sectional view of the above-mentioned rolled body after flattening, taken along a plane perpendicular to the axial direction. [Figure 6] FIG. 6 is a schematic plan view of the pre-wound film before winding. [Figure 7] FIG. 7 is a schematic plan view of the metallized film before rolling. [Figure 8] FIG. 8 is a schematic plan view of the leading-wound film before winding in the second embodiment. [Figure 9] FIG. 9 is a schematic plan view of the leading-wound film before winding in the third embodiment. [Figure 10]FIG. 10 is a schematic plan view of the leading film before winding in the fourth embodiment. [Figure 11] FIG. 11 is a schematic plan view of the preceding film before winding in the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] 1. Overview In order to solve the problems that the metallized film capacitors of Patent Documents 1 to 3 have, the present inventors have continued their intensive research and have developed the following film capacitor 1.

[0014] That is, the film capacitor 1 according to this embodiment includes a capacitor element 10 (see FIG. 1). The capacitor element 10 includes a wound body 6 and a pair of end electrodes 7 provided on both end surfaces of the wound body 6. The wound body 6 includes a winding core 20 around which a previously wound film 2 is wound, and a metallized film 5 wound around the winding core 20 (see FIGS. 2 to 5). The metallized film 5 includes a dielectric film 3 and a metal film 4 provided on the dielectric film 3 (see FIG. 7). The previously wound film 2 includes an electrically insulating film 8 and a heat conductive film 9 provided on the film 8 (see FIGS. 6, 8 to 11).

[0015] The film capacitor 1 according to this embodiment is manufactured using only one winding core 20 for one capacitor element 10. Therefore, the film capacitor 1 can be manufactured with good workability without using special equipment.

[0016] Furthermore, the pre-wound film 2 for forming the core 20 has a heat conductive film 9, so that the heat dissipation at the center of the capacitor element 10 is high.

[0017] Furthermore, since there are almost no steps on the outer peripheral surface of winding core 20, metallized film 5 is less likely to wrinkle when wound around winding core 20. Therefore, metallized film 5 is wound evenly in film capacitor 1.

[0018] 2.Details (1) First embodiment (1.1) Film capacitor A film capacitor 1 according to a first embodiment will be described below with reference to Figures 1 to 7. Each figure is a schematic diagram, and the ratios of the sizes and thicknesses of the components in each figure do not necessarily reflect the actual dimensional ratios.

[0019] The arrows indicating the various directions in each figure are not intended to define the directions in which the film capacitor 1 should be used, but are merely used to make the explanation easier to understand, and do not have any substance.

[0020] 1 to 5, the Z direction, R direction, and θ direction of the cylindrical coordinate system are defined. The Z direction is the axial direction of the wound body 6. The +Z direction is the direction from the second end face 62 to the first end face 61. The -Z direction is the opposite direction to the +Z direction. The R direction is the radial direction of the wound body 6. The +R direction is the direction away from the winding core 20 and is sometimes referred to as the "radially outward direction." The -R direction is the opposite direction to the +R direction and is sometimes referred to as the "radially inward direction." The θ direction is the winding direction of the pre-wound film 2 and the metallized film 5.

[0021] 6 and 7, the X, Y, and Z directions of a Cartesian coordinate system are defined (the same applies to FIGS. 8 to 11). The X direction is the thickness direction of the preceding film 2 and the metallized film 5. The X direction corresponds to the R direction of the cylindrical coordinate system. The Y direction is the longitudinal direction of the preceding film 2 and the metallized film 5. The Y direction corresponds to the θ direction of the cylindrical coordinate system. The Z direction is the width direction of the preceding film 2 and the metallized film 5. The Z direction corresponds to the Z direction of the cylindrical coordinate system. Therefore, with regard to the Z direction in the cylindrical coordinate system and the Cartesian coordinate system, the +Z direction is sometimes referred to as "one axial side" and the -Z direction is sometimes referred to as "the other axial side."

[0022] 1, the film capacitor 1 according to the first embodiment includes a capacitor element 10. In the first embodiment, the film capacitor 1 includes only one capacitor element 10, but may include multiple capacitor elements 10. The film capacitor 1 may further include a bus bar (not shown).

[0023] 1, capacitor element 10 has a wound body 6 and a pair of end electrodes 7. Each of the components will be described below in order.

[0024] (1.1.1) Wound body The wound body 6 is the main body of the capacitor element 10. The wound body 6 has the shape of a rounded rectangular column extending in the axial direction (Z direction). That is, when viewed along the axial direction, the wound body 6 has a rounded rectangle. A rounded rectangle has, for example, a shape in which two short sides of a rectangle are joined to semicircles whose diameter is the short sides. The shape of the wound body 6 is not particularly limited, but examples thereof include a cylindrical shape and an oval cylindrical shape.

[0025] The wound body 6 has a pair of end faces 60. The pair of end faces 60 is a first end face 61 and a second end face 62. The first end face 61 is a face facing one side in the axial direction. The second end face 62 is a face opposite the first end face 61. In other words, the second end face 62 is a face facing the other side in the axial direction.

[0026] 2 and 3 show the cylindrical wound body 6 before flattening, while Fig. 4 and 5 show the rounded rectangular cylindrical wound body 6 after flattening. In the first embodiment, the film capacitor 1 is manufactured using the flattened wound body 6, but the film capacitor 1 may also be manufactured using the unflattened wound body 6.

[0027] The wound body 6 includes a winding core 20 and a metallized film 5. In the first embodiment, the wound body 6 further includes an exterior film 63. The wound body 6 does not necessarily have to include the exterior film 63.

[0028] <Core> Winding core 20 is used to wind metallized film 5 and also serves as a heat dissipation path. Winding core 20 is located approximately in the center of wound body 6 when viewed along the axial direction (Z direction) (see FIGS. 3 and 5).

[0029] The winding core 20 extends from the first end surface 61 to the second end surface 62 of the wound body 6. In other words, the winding core 20 is continuous between the first end surface 61 and the second end surface 62 of the wound body 6. In this way, only one winding core 20 is used for one capacitor element 10.

[0030] The winding core 20 is wound with the previously wound film 2. Before the wound body 6 is flattened, the winding core 20 has a cylindrical shape extending in the axial direction (Z direction), as shown in Figures 2 and 3. On the other hand, after the wound body 6 is flattened, the winding core 20 has a plate shape extending in the axial direction (Z direction), as shown in Figures 1, 4, and 5. In other words, as the wound body 6 is flattened, the winding core 20 is also crushed and flattened.

[0031] <Pre-wound film> 6 shows the leading film 2 (first leading film 2A) before being wound. The leading film 2 is long. That is, the longitudinal direction of the leading film 2 is the Y direction.

[0032] The length of the leading-wound film 2 in the width direction (Z direction) is approximately equal to the length of the roll 6 in the axial direction (Z direction). Here, "the length in the axial direction of the roll 6" means the distance between the first end face 61 and the second end face 62. In the first embodiment, the length of the leading-wound film 2 in the width direction is slightly longer than the length of the roll 6 in the axial direction (see FIGS. 2 and 4). Note that, as long as the effect of the first embodiment is not impaired, the length of the leading-wound film 2 in the width direction may be the same as the length of the roll 6 in the axial direction, or may be shorter than the length of the roll 6 in the axial direction.

[0033] 6, the leading film 2 includes a film 8 and a heat conductive film 9. In the first embodiment, the leading film 2 further includes an insulating region 80.

[0034] 〔film〕 The film 8 is long and electrically insulating. The material of the film 8 is not particularly limited, but examples thereof include polypropylene (PP) and polyethylene terephthalate (PET).

[0035] Here, PP film is softer than PET film, so winding core 20 formed using PP film is easily flattened. On the other hand, PET film is less susceptible to heat damage caused by vapor deposition than PP film. Therefore, when forming thermally conductive film 9 by vapor deposition, using PET film makes it easier to thicken thermally conductive film 9. When thermally conductive film 9 is thickened, the heat dissipation properties of capacitor element 10 can be improved.

[0036] The thickness of the film 8 is not particularly limited, but is, for example, 1 μm or more and 50 μm or less.

[0037] [Thermal conductive film] The thermally conductive film 9 is a film for transferring heat generated inside the capacitor element 10 to the outside. The thermally conductive film 9 is provided on the film 8. The thermally conductive film 9 is formed by, for example, vapor deposition.

[0038] The thermally conductive film 9 contains a metal. The metal is not particularly limited, but examples thereof include silver, copper, gold, aluminum, nickel, platinum, etc. The thermally conductive film 9 may contain aluminum nitride (AlN), boron nitride (BN), graphite, silicon carbide (SiC), etc.

[0039] The thermally conductive film 9 may be provided on only one side of the film 8, or on both sides of the film 8. When the thermally conductive film 9 is provided on both sides of the film 8, the heat dissipation of the capacitor element 10 may be improved compared to when the thermally conductive film 9 is provided on only one side of the film 8. Furthermore, when the thermally conductive film 9 is provided on both sides of the film 8, capacitance may be generated in the portions where the thermally conductive films 9 face each other with the film 8 interposed therebetween.

[0040] When forming the winding core 20, if the thermally conductive film 9 is provided on only one side of the film 8, the preceding film 2 may be wound with the thermally conductive film 9 on the radially outer side, or the preceding film 2 may be wound with the thermally conductive film 9 on the radially inner side.

[0041] The thickness of the thermally conductive film 9 is preferably 1 Å or more, and more preferably 10 Å or more. When the thickness of the thermally conductive film 9 is 1 Å or more, the heat dissipation properties of the capacitor element 10 can be improved. On the other hand, the thickness of the thermally conductive film 9 is preferably 1000 Å or less, and more preferably 100 Å or less. When the thickness of the thermally conductive film 9 is 1000 Å or less, the film 8 is less susceptible to heat damage when the thermally conductive film 9 is formed by vapor deposition. Furthermore, the wound body 6 can be more easily flattened.

[0042] 6, in the first embodiment, the thermally conductive film 9 includes a first thermally conductive film 91 and a second thermally conductive film 92. In this manner, the thermally conductive film 9 is divided into a plurality of parts.

[0043] The first thermally conductive film 91 extends along the longitudinal direction of the preceding film 2. The first thermally conductive film 91 is provided on one widthwise side of the film 8 relative to the center line C of the preceding film 2. The edge on one axial side of the first thermally conductive film 91 roughly coincides with the edge on one axial side of the film 8. As a result, the edge on one axial side of the first thermally conductive film 91 is exposed at the first end face 61 of the roll 6. The edge on the other axial side of the first thermally conductive film 91 is located on one axial side of the center line C of the preceding film 2 and extends linearly in the longitudinal direction.

[0044] On the other hand, like the first thermally conductive film 91, the second thermally conductive film 92 also extends along the longitudinal direction of the leading-wound film 2. The second thermally conductive film 92 is provided on the other widthwise side of the film 8 relative to the center line C of the leading-wound film 2. The edge on the other axial side of the second thermally conductive film 92 substantially coincides with the edge on the other axial side of the film 8. As a result, the edge on the other axial side of the second thermally conductive film 92 is exposed at the second end face 62 of the roll 6. The edge on one axial side of the second thermally conductive film 92 is located on the other axial side of the center line C of the leading-wound film 2 and extends linearly in the longitudinal direction.

[0045] The "center line C of the previously wound film 2" is a line passing through the center of the previously wound film 2 (film 8) in the width direction (Z direction). In the wound body 6, the part corresponding to the center line C of the previously wound film 2 is located in part A surrounded by a dotted line in FIG. 4. Part A corresponds to the center of the capacitor element 10.

[0046] [Insulation area] The insulating region 80 is an electrically insulated region. The thermally conductive film 9 is not provided in the insulating region 80. In other words, the insulating region 80 is a region where the film 8 is exposed.

[0047] 6, the insulating region 80 divides the thermally conductive film 9 into a first thermally conductive film 91 and a second thermally conductive film 92. In other words, the insulating region 80 is a region that exists between the edge of the first thermally conductive film 91 on the other axial side and the edge of the second thermally conductive film 92 on one axial side. In this way, the first thermally conductive film 91 and the second thermally conductive film 92 are not connected.

[0048] The insulating region 80 has a linear or strip-like shape and extends in the longitudinal direction (Y direction) of the preceding-wound film 2. In this manner, the insulating region 80 extends in the longitudinal direction of the preceding-wound film 2.

[0049] At least a part of the insulating region 80 (the whole of it in the first embodiment) is present in the widthwise center of the preceding film 2. In this manner, the insulating region 80 is a region that includes the center line C of the preceding film 2.

[0050] The width W1 of the insulating region 80 is preferably 0.1 mm or more, and more preferably 1 mm or more. When the width W1 of the insulating region 80 is 0.1 mm or more, it is possible to suppress short circuits caused by the pre-wound film 2. On the other hand, the width W1 of the insulating region 80 is preferably 10 mm or less, and more preferably 3 mm or less. When the width W1 of the insulating region 80 is 10 mm or less, it is possible to improve the heat dissipation properties of the capacitor element 10. Note that the "width W1 of the insulating region 80" means the length along the direction perpendicular to the direction in which the insulating region 80 extends.

[0051] <Metallized film> Metallized film 5 is long and wound around core 20 (see FIGS. 2 to 5).

[0052] The length of metallized film 5 in the width direction (Z direction) is approximately equal to the length of roll 6 in the axial direction (Z direction). Note that, as long as the effect of the first embodiment is not impaired, the length of metallized film 5 in the width direction may be shorter than the length of roll 6 in the axial direction.

[0053] In the first embodiment, the length in the width direction (Z direction) of the metallized film 5 is shorter than the length in the width direction (Z direction) of the preceding film 2. Note that, as long as the effect of the first embodiment is not impaired, the length in the width direction of the metallized film 5 may be the same as the length in the width direction of the preceding film 2 or may be longer than the length in the width direction of the preceding film 2.

[0054] In the first embodiment, two metallized films 5 are stacked and wound around the winding core 20. The two metallized films 5 are a first metallized film 51 and a second metallized film 52. Hereinafter, unless otherwise specified, the first metallized film 51 and the second metallized film 52 will be collectively referred to as the metallized film 5.

[0055] 7 shows the metallized film 5 before being wound. The metallized film 5 has a dielectric film 3 and a metal film 4. In the first embodiment, the metallized film 5 further has a margin portion 30. When two metallized films 5 are wound around the winding core 20, the first metallized film 51 and the second metallized film 52 are stacked with a slight offset in the width direction (Z direction) as shown in FIG.

[0056] <Dielectric film> The material of the dielectric film 3 is not particularly limited, but examples thereof include polypropylene (PP), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyphenylene sulfide (PPS), polycarbonate (PC), and polystyrene (PS).

[0057] The thickness of the dielectric film 3 is not particularly limited relative to the thickness of the film 8 of the previously wound film 2. Specifically, the thickness of the film 8 of the previously wound film 2 may be the same as the thickness of the dielectric film 3, or may be thicker or thinner than the thickness of the dielectric film 3. For example, when the thickness of the film 8 of the previously wound film 2 is thicker than the thickness of the dielectric film 3, a thicker thermally conductive film 9 can be formed on the film 8. On the other hand, when the thickness of the film 8 of the previously wound film 2 is thinner than the thickness of the dielectric film 3, the element size can be reduced.

[0058] The thickness of the dielectric film 3 is not particularly limited, but is, for example, 1 μm or more and 30 μm or less. When the thickness of the dielectric film 3 is 1 μm or more, dielectric breakdown can be suppressed. On the other hand, when the thickness of the dielectric film 3 is 30 μm or less, the capacitance of the film capacitor 1 can be increased.

[0059] <Metal Film> The metal film 4 is provided on the dielectric film 3. In the first embodiment, the metal film 4 is provided on only one surface of the dielectric film 3. The metal film 4 is formed by, for example, vapor deposition.

[0060] The material of the metal film 4 is not particularly limited, but examples thereof include aluminum (Al), gold (Au), magnesium (Mg), zinc (Zn), tin (Sn), nickel (Ni), chromium (Cr), iron (Fe), copper (Cu), titanium (Ti), and alloys thereof.

[0061] 7, the metal film 4 includes a plurality of segmented electrodes 4a, a non-segmented electrode 4b, and a plurality of fuses 4c. The segmented electrodes 4a are aligned along the longitudinal direction (Y direction) of the metallized film 5. The non-segmented electrode 4b extends along the longitudinal direction of the metallized film 5. Each of the plurality of fuses 4c connects the segmented electrode 4a to the non-segmented electrode 4b. The fuses 4c melt when an excessive current flows due to dielectric breakdown or the like.

[0062] Here, in metal film 4 (first metal film 41) of first metallized film 51, multiple divided electrodes 4a are arranged on the other axial side of dielectric film 3, and non-divided electrode 4b is arranged on one axial side of dielectric film 3. The edge on one axial side of non-divided electrode 4b of first metal film 41 is substantially aligned with the edge on one axial side of dielectric film 3. As a result, the edge on one axial side of first metal film 41 is exposed at first end face 61 of wound body 6.

[0063] On the other hand, with respect to metal film 4 (second metal film 42) of second metallized film 52, multiple divided electrodes 4a are arranged on one axial side of dielectric film 3, and non-divided electrode 4b is arranged on the other axial side of dielectric film 3. The edge on the other axial side of non-divided electrode 4b of second metal film 42 is substantially aligned with the edge on the other axial side of dielectric film 3. As a result, the edge on the other axial side of second metal film 42 is exposed at second end surface 62 of wound body 6.

[0064] In this way, the pattern of the first metal film 41 and the pattern of the second metal film 42 are inverted relative to each other in the axial direction (Z direction). Inside the capacitor element 10, the first metal film 41 and the second metal film 42 face each other via the dielectric film 3. This generates capacitance.

[0065] The pattern of the metal film 4 is not limited to that shown in Fig. 7. For example, it is also possible to adopt the features described in Japanese Patent Application Laid-Open Nos. 2004-134561, 2-33910, and 3-101508.

[0066] The thickness of the metal film 4 is thinner than the thickness of the thermally conductive film 9. In other words, the thickness of the thermally conductive film 9 is thicker than the thickness of the metal film 4. This makes it easier for heat generated inside the capacitor element 10 to pass through the thermally conductive film 9 and move to the outside.

[0067] Here, when comparing the thickness of the metal film 4 with the thickness of the thermally conductive film 9, the thickness of the metal film 4 means the thickness of the portion other than the so-called heavy edge. Note that the heavy edge is also described in, for example, the above-mentioned Japanese Patent Application Laid-Open No. 2004-134561.

[0068] <Margin> The margin portion 30 is provided to prevent short circuits. The metal film 4 is not provided in the margin portion 30. In other words, the margin portion 30 is a region where the dielectric film 3 is exposed.

[0069] Here, margin portion 30 of first metallized film 51 has a linear or strip-like shape extending in the longitudinal direction, and is a region that exists between first metal film 41 (plurality of divided electrodes 4a) and the other axial edge of dielectric film 3. Therefore, first metal film 41 is not exposed at second end surface 62 of wound body 6. As a result, first metal film 41 does not contact second end surface electrode 72 on the opposite side, ensuring insulation.

[0070] On the other hand, margin portion 30 of second metallized film 52 has a linear or strip-like shape extending in the longitudinal direction, and is a region that exists between second metal film 42 (plurality of divided electrodes 4a) and one axial edge of dielectric film 3. As a result, second metal film 42 is not exposed at first end surface 61 of wound body 6. As a result, second metal film 42 does not contact first end surface electrode 71 on the opposite side, ensuring insulation.

[0071] The width W2 of the margin portion 30 is equal to or less than the width W1 of the insulating region 80. In other words, the width W1 of the insulating region 80 is equal to or greater than the width W2 of the margin portion 30. This makes it possible to suppress short circuits caused by the pre-wound film 2. Note that the "width W2 of the margin portion 30" refers to the length along a direction perpendicular to the direction in which the margin portion 30 extends.

[0072] <Exterior film> Exterior film 63 is disposed on the entire side surface of roll 6. Exterior film 63 covers rolled metallized film 5.

[0073] The exterior film 63 has electrical insulation properties and is made of the same material as the dielectric film 3.

[0074] (1.1.2) A pair of end electrodes 1, a pair of end surface electrodes 7 are provided on both end surfaces of the wound body 6. Specifically, the pair of end surface electrodes 7 are a first end surface electrode 71 and a second end surface electrode 72.

[0075] The first end surface electrode 71 is formed by spraying a metal onto the first end surface 61 of the wound body 6. On the other hand, the second end surface electrode 72 is formed by spraying a metal onto the second end surface 62 of the wound body 6. The metal constituting the first end surface electrode 71 and the second end surface electrode 72 is not particularly limited, but examples thereof include zinc (Zn), tin (Sn), and alloys thereof.

[0076] The metal film 4 is in contact with one of the pair of end electrodes 7. Specifically, the edge of the first metal film 41 is exposed at the first end surface 61 of the wound body 6 and is therefore in contact with the first end surface electrode 71. In this way, the first end surface electrode 71 is electrically connected to the first metal film 41. Furthermore, the edge of the first thermally conductive film 91 is also exposed at the first end surface 61 of the wound body 6 and is therefore in contact with the first end surface electrode 71.

[0077] On the other hand, the edge of the second metal film 42 is exposed at the second end surface 62 of the wound body 6 and is therefore in contact with the second end surface electrode 72. In this manner, the second end surface electrode 72 is electrically connected to the second metal film 42. Furthermore, the edge of the second thermally conductive film 92 is also exposed at the second end surface 62 of the wound body 6 and is therefore in contact with the second end surface electrode 72.

[0078] The metal film 4 is separated from the other of the pair of end surface electrodes 7 via a margin 30. Specifically, the first metal film 41 is separated from the second end surface electrode 72 via the margin 30. In this way, the first metal film 41 is not in contact with the second end surface electrode 72.

[0079] On the other hand, the second metal film 42 is separated from the first end surface electrode 71 via the margin portion 30. In this manner, the second metal film 42 is not in contact with the first end surface electrode 71.

[0080] The preceding film 2 is electrically insulated between the pair of end electrodes 7 (the first end electrode 71 and the second end electrode 72). Specifically, the insulating region 80 of the preceding film 2 electrically insulates the first thermally conductive film 91 from the second end electrode 72, and electrically insulates the second thermally conductive film 92 from the first end electrode 71.

[0081] (1.2) Film capacitor manufacturing method The film capacitor 1 according to the first embodiment is manufactured as follows.

[0082] First, the pre-wound film 2 is wound to form the winding core 20. At this time, if the thermally conductive film 9 is provided on only one side of the film 8, the thermally conductive film 9 may be disposed on either the radially inner side or the radially outer side when the pre-wound film 2 is wound.

[0083] Next, metallized film 5 is wound around winding core 20 to form cylindrical wound body 6 (see FIGS. 2 and 3). At this time, first metallized film 51 and second metallized film 52 are overlapped and wound around winding core 20 so that first metal film 41 and second metal film 42 face each other with dielectric film 3 interposed therebetween.

[0084] Here, when thermally conductive film 9 is present on the outside of winding core 20, metallized film 5 is wound around winding core 20 with metal film 4 on the outside. This makes it possible to avoid contact between thermally conductive film 9 and metal film 4.

[0085] On the other hand, when the thermally conductive film 9 is not present on the outside of the winding core 20, the metallized film 5 may be wound around the winding core 20 with the metal film 4 on the outside, or the metallized film 5 may be wound around the winding core 20 with the metal film 4 on the inside.

[0086] Next, the cylindrical wound body 6 is flattened to obtain a rounded rectangular cylindrical wound body 6 (see FIGS. 4 and 5). Here, the flattening is performed by pressing the cylindrical wound body 6 in the radial direction (R direction).

[0087] Then, metal is sprayed onto both end surfaces of the flattened wound body 6 to form end electrodes 7. This results in the film capacitor 1 (capacitor element 10) shown in Fig. 1. After this, bus bars (not shown) may be joined to the end electrodes 7 by soldering or the like.

[0088] (1.3) Action and effect In the first embodiment, the workability when manufacturing the film capacitor 1 is good because only one winding core 20 needs to be used for one capacitor element 10. Therefore, there is no need to use special equipment.

[0089] Furthermore, the film capacitor 1 according to the first embodiment can be charged by applying a voltage between the end electrodes 7. Conversely, it can be discharged through the end electrodes 7. When the film capacitor 1 is repeatedly charged and discharged in this manner, the capacitor element 10 generates heat. In general, heat tends to accumulate in the center of the capacitor element 10 (the area corresponding to part A in FIG. 4).

[0090] However, in the first embodiment, since the thermally conductive film 9 (first thermally conductive film 91 and second thermally conductive film 92) is present in the center of the capacitor element 10, the heat generated in the center of the capacitor element 10 passes through the thermally conductive film 9 to reach the end electrodes 7 and is then directly discharged to the outside of the film capacitor 1. In this way, in the first embodiment, heat is less likely to accumulate in the center of the capacitor element 10. In other words, the center of the capacitor element 10 has high heat dissipation properties.

[0091] Furthermore, in the first embodiment, the metallized film 5 is wound uniformly in the film capacitor 1. This is because, as described above, only one winding core 20 is used for one capacitor element 10, and there are almost no steps on the outer circumferential surface of one winding core 20. Even if there are steps, they are negligible.

[0092] Therefore, according to the first embodiment, it is possible to provide a film capacitor 1 that can be manufactured with good workability without using special equipment, has high heat dissipation properties at the center of the capacitor element, and has a metallized film wound evenly.

[0093] (2) Second embodiment Next, a film capacitor 1 according to a second embodiment will be described with reference to Fig. 8. In the second embodiment, the same components as those in the first embodiment will be denoted by the same reference numerals as in the first embodiment, and detailed description thereof may be omitted.

[0094] (2.1) Film capacitor In the second embodiment, the pattern of the thermally conductive film 9 and the insulating region 80 in the leading winding film 2 (second leading winding film 2B) differs from the pattern of the thermally conductive film 9 and the insulating region 80 in the leading winding film 2 (first leading winding film 2A) in the first embodiment. The following description will focus on the differences from the first embodiment.

[0095] [Thermal conductive film] As shown in FIG. 8 , in the second embodiment, the thermally conductive film 9 is a single film and is not divided into multiple pieces. The thermally conductive film 9 extends along the longitudinal direction of the previously wound film 2. One axial edge of the thermally conductive film 9 substantially coincides with one axial edge of the film 8. This allows the one axial edge of the thermally conductive film 9 to be exposed at the first end face 61 of the wound body 6. This allows the thermally conductive film 9 to come into contact with the first end face electrode 71 of the capacitor element 10. Meanwhile, the other axial edge of the thermally conductive film 9 is located on the other axial side of the center line C of the previously wound film 2 and extends linearly in the longitudinal direction. In this way, the thermally conductive film 9 crosses the center line C of the previously wound film 2.

[0096] In the second embodiment, similarly to the first embodiment, the heat conduction film 9 may be provided on only one side of the film 8, or on both sides of the film 8.

[0097] [Insulation area] In the second embodiment, the insulating region 80 is located in contact with one of the pair of end electrodes 7. Specifically, the insulating region 80 is a region that exists between the other axial edge of the thermally conductive film 9 and the other axial edge of the film 8. Therefore, in the capacitor element 10, the insulating region 80 is located in contact with the second end electrode 72. Because the insulating region 80 is thus interposed between the thermally conductive film 9 and the second end electrode 72, the thermally conductive film 9 does not contact the second end electrode 72 in the capacitor element 10.

[0098] In the second embodiment, the insulating region 80 also has a linear or strip-like shape and extends in the longitudinal direction (Y direction) of the leading-wound film 2. In this manner, the insulating region 80 extends in the longitudinal direction of the leading-wound film 2.

[0099] (2.2) Action and effect The second embodiment also provides the same effects as the first embodiment.

[0100] In particular, in the second embodiment, as shown in Fig. 8, the thermally conductive film 9 crosses the center line C of the pre-wound film 2. Therefore, heat generated in the center of the capacitor element 10 immediately passes through the thermally conductive film 9 to reach the end electrodes 7 and is then directly discharged to the outside of the film capacitor 1. In other words, the heat dissipation ability of the center of the capacitor element 10 is even higher.

[0101] Moreover, since the patterns of the thermally conductive film 9 and the insulating region 80 of the second leading film 2B are relatively simple, the second leading film 2B is easy to manufacture.

[0102] (3) Third embodiment Next, a film capacitor 1 according to a third embodiment will be described with reference to Fig. 9. In the third embodiment, the same components as those in the first and second embodiments will be assigned the same reference numerals as those in the first and second embodiments, and detailed description thereof may be omitted.

[0103] (3.1) Film capacitor In the third embodiment, the patterns of the heat conductive film 9 and the insulating regions 80 in the leading winding film 2 (third leading winding film 2C) are different from the patterns of the heat conductive film 9 and the insulating regions 80 in the leading winding films 2 of the first and second embodiments. The following description will focus on the differences from the first and second embodiments.

[0104] [Thermal conductive film] 9, in the third embodiment, the edge of the first thermal conduction film 91 on the other axial side has a triangular wave shape. In other words, the first thermal conduction film 91 has a shape on the other axial side in which peaks and valleys are alternately arranged along the longitudinal direction.

[0105] Meanwhile, the edge on one axial side of the second thermal conduction film 92 also has a triangular wave shape. In other words, the second thermal conduction film 92 has a shape on one axial side in which peaks and valleys are alternately arranged along the longitudinal direction.

[0106] The peaks of the first thermally conductive film 91 and the valleys of the second thermally conductive film 92 face each other in the axial direction, and the valleys of the first thermally conductive film 91 and the peaks of the second thermally conductive film 92 face each other in the axial direction. The peaks of the peaks of the first thermally conductive film 91 and the peaks of the second thermally conductive film 92 are located on the center line C of the preceding film 2.

[0107] It is preferable that the thermally conductive film 9 is provided on only one side of the film 8. This makes it possible to prevent short circuits caused by the pre-wound film 2.

[0108] [Insulation area] In the third embodiment, the insulating region 80 has a triangular wave shape (zigzag shape) along the longitudinal direction of the preceding film 2. In this way, the insulating region 80 extends in the longitudinal direction of the preceding film 2 while bending in a jagged manner.

[0109] Furthermore, the insulating region 80 extends in the longitudinal direction while crossing the center line C of the previously-wound film 2. That is, at least a portion of the insulating region 80 is present in the center of the previously-wound film 2 in the width direction.

[0110] (3.2) Action and Effect The third embodiment also provides the same effects as the first embodiment.

[0111] 9, in the third embodiment, both a portion of the first thermally conductive film 91 (the apexes of the multiple ridges) and a portion of the second thermally conductive film 92 (the apexes of the multiple ridges) are likely to be located on the center line C of the pre-wound film 2. Therefore, heat generated in the center of the capacitor element 10 immediately passes through the thermally conductive film 9 to reach the end electrode 7 and is then directly discharged to the outside of the film capacitor 1. In other words, the heat dissipation ability of the center of the capacitor element 10 is even higher.

[0112] (4) Fourth embodiment Next, a film capacitor 1 according to a fourth embodiment will be described with reference to Fig. 10. In the fourth embodiment, the same components as those in the first to third embodiments will be denoted by the same reference numerals as those in the first to third embodiments, and detailed description thereof may be omitted.

[0113] (4.1) Film capacitor In the fourth embodiment, the patterns of the heat conductive film 9 and the insulating regions 80 in the leading winding film 2 (fourth leading winding film 2D) are different from the patterns of the heat conductive film 9 and the insulating regions 80 in the leading winding films 2 of the first to third embodiments. The following description will focus on the differences from the first to third embodiments.

[0114] [Thermal conductive film] 10, the fourth embodiment includes a plurality of first thermally conductive films 91 and a plurality of second thermally conductive films 92. The first thermally conductive films 91 and the second thermally conductive films 92 are arranged alternately along the longitudinal direction.

[0115] Each of the plurality of first thermally conductive films 91 and the plurality of second thermally conductive films 92 has a rectangular shape and crosses the center line C of the preceding film 2.

[0116] The edge of the first thermally conductive film 91 on one axial side is substantially aligned with the edge of the film 8 on one axial side. As a result, the edge of the first thermally conductive film 91 on one axial side is exposed at the first end face 61 of the roll 6. The edge of the first thermally conductive film 91 on the other axial side is located between the center line C of the preceding film 2 and the edge of the film 8 on the other axial side.

[0117] On the other hand, the edge on the other axial side of the second thermally conductive film 92 is substantially aligned with the edge on the other axial side of the film 8. As a result, the edge on the other axial side of the second thermally conductive film 92 is exposed at the second end face 62 of the roll 6. The edge on one axial side of the second thermally conductive film 92 is located between the center line C of the preceding film 2 and the edge on one axial side of the film 8.

[0118] It is preferable that the thermally conductive film 9 is provided on only one side of the film 8. This can prevent short circuits caused by the pre-wound film 2.

[0119] [Insulation area] 10, in the fourth embodiment, the insulating region 80 has a rectangular wave shape (crank shape) along the longitudinal direction of the preceding film 2. In this manner, the insulating region 80 extends in the longitudinal direction of the preceding film 2.

[0120] Furthermore, the insulating region 80 extends in the longitudinal direction while axially crossing the center line C of the previously-wound film 2. That is, at least a portion of the insulating region 80 is present in the center of the previously-wound film 2 in the width direction.

[0121] (4.2) Action and Effect The fourth embodiment also provides the same effects as the first embodiment.

[0122] 10, in the fourth embodiment, both the first thermally conductive film 91 and the second thermally conductive film 92 cross the center line C of the leading-wound film 2. Therefore, heat generated in the center of the capacitor element 10 immediately passes through the thermally conductive film 9 to reach the end electrode 7 and is then directly discharged to the outside of the film capacitor 1. In other words, the heat dissipation performance of the center of the capacitor element 10 is even higher.

[0123] (5) Fifth embodiment Next, a film capacitor 1 according to a fifth embodiment will be described with reference to Fig. 11. In the fifth embodiment, the same components as those in the first to fourth embodiments will be denoted by the same reference numerals as those in the first to fourth embodiments, and detailed description thereof may be omitted.

[0124] (5.1) Film capacitor In the fifth embodiment, the patterns of the heat conductive film 9 and the insulating regions 80 in the leading winding film 2 (fifth leading winding film 2E) are different from the patterns of the heat conductive film 9 and the insulating regions 80 in the leading winding films 2 of the first to fourth embodiments. The following description will focus on the differences from the first to fourth embodiments.

[0125] [Thermal conductive film] 11, the fifth embodiment includes a plurality of first thermally conductive films 91 and a plurality of second thermally conductive films 92. The first thermally conductive films 91 and the second thermally conductive films 92 are arranged alternately along the longitudinal direction.

[0126] Each of the plurality of first thermally conductive films 91 and the plurality of second thermally conductive films 92 has a mountain shape and crosses the center line C of the preceding film 2.

[0127] The edge of the first thermally conductive film 91 on one axial side is substantially aligned with the edge of the film 8 on one axial side. As a result, the edge of the first thermally conductive film 91 on one axial side is exposed at the first end face 61 of the roll 6. The edge of the first thermally conductive film 91 on the other axial side is located between the center line C of the preceding film 2 and the edge of the film 8 on the other axial side.

[0128] On the other hand, the edge on the other axial side of the second thermally conductive film 92 is substantially aligned with the edge on the other axial side of the film 8. As a result, the edge on the other axial side of the second thermally conductive film 92 is exposed at the second end face 62 of the roll 6. The edge on one axial side of the second thermally conductive film 92 is located between the center line C of the preceding film 2 and the edge on one axial side of the film 8.

[0129] It is preferable that the thermally conductive film 9 is provided on only one side of the film 8. This can prevent short circuits caused by the pre-wound film 2.

[0130] [Insulation area] 11, in the fifth embodiment, the insulating region 80 has a sinusoidal (curved) shape along the longitudinal direction of the preceding film 2. In this way, the insulating region 80 extends in the longitudinal direction of the preceding film 2 while meandering.

[0131] Furthermore, the insulating region 80 extends in the longitudinal direction while crossing the center line C of the previously-wound film 2. That is, at least a portion of the insulating region 80 is present in the center of the previously-wound film 2 in the width direction.

[0132] (5.2) Action and Effect The fifth embodiment also provides the same effects as the first embodiment.

[0133] In particular, in the fifth embodiment, as shown in Fig. 11, both the first thermally conductive film 91 and the second thermally conductive film 92 cross the center line C of the leading-wound film 2. Therefore, heat generated in the center of the capacitor element 10 immediately passes through the thermally conductive film 9 to reach the end electrode 7 and is then directly discharged to the outside of the film capacitor 1. In other words, the heat dissipation ability of the center of the capacitor element 10 is even higher. Furthermore, because the insulating region 80 is smoothly curved, the fifth leading-wound film 2E is easier to manufacture than the fourth leading-wound film 2D.

[0134] 3. Variations In the first leading-wound film 2A, the insulating region 80 is located in the widthwise center of the first leading-wound film 2A, but the insulating region 80 may be located on one or the other side in the widthwise direction of the leading-wound film 2. The same applies to the third leading-wound film 2C.

[0135] 4. Aspects As is clear from the above-described embodiments and modifications, the present disclosure includes the following aspects. In the following, reference numerals are given in parentheses only to clarify the correspondence with the embodiments.

[0136] The first aspect is a film capacitor (1) comprising a capacitor element (10). The capacitor element (10) comprises a wound body (6) and a pair of end electrodes (7) provided on both end surfaces of the wound body (6). The wound body (6) comprises a winding core (20) around which a previously wound film (2) is wound, and a metallized film (5) having a dielectric film (3) and a metal film (4) provided on the dielectric film (3), and wound around the winding core (20). The previously wound film (2) comprises an electrically insulating film (8) and a heat conductive film (9) provided on the film (8).

[0137] According to this embodiment, the film capacitor 1 can be manufactured with good workability without using special equipment. The central portion of the capacitor element 10 of the film capacitor 1 has high heat dissipation. Furthermore, the metallized film 5 is wound uniformly around the film capacitor 1.

[0138] The second aspect is a film capacitor (1) based on the first aspect. In the second aspect, the pre-wound film (2) is electrically insulated between a pair of end electrodes (7).

[0139] According to this embodiment, it is possible to prevent short circuits caused by the preceding film (2).

[0140] A third aspect is a film capacitor (1) based on the first or second aspect. In the third aspect, the pre-wound film (2) further has an insulating region (80) where the thermally conductive film (9) is not provided.

[0141] According to this embodiment, the insulating region (80) can suppress short circuits caused by the preceding film (2).

[0142] The fourth embodiment is a film capacitor (1) based on the third embodiment. In the fourth embodiment, the insulating region (80) extends in the longitudinal direction of the pre-wound film (2).

[0143] According to this embodiment, the insulating region (80) can suppress short circuits caused by the preceding film (2).

[0144] A fifth aspect is a film capacitor (1) based on the third or fourth aspect. In the fifth aspect, at least a part of the insulating region (80) is present in the widthwise center of the preceding film (2).

[0145] According to this embodiment, the insulating region (80) can suppress short circuits caused by the preceding film (2).

[0146] The sixth aspect is a film capacitor (1) based on any one of the third to fifth aspects. In the sixth aspect, the insulating region (80) is located in a position where it contacts one of the pair of end electrodes (7).

[0147] According to this embodiment, the heat dissipation properties of the capacitor element (10) can be further improved.

[0148] The seventh aspect is a film capacitor (1) based on any one of the third to sixth aspects. In the seventh aspect, the insulating region (80) has a triangular wave, a rectangular wave, or a sine wave shape along the longitudinal direction of the leading film (2).

[0149] According to this embodiment, the heat conductive film (9) can be easily positioned in the widthwise central portion of the preceding film (2).

[0150] An eighth aspect is a film capacitor (1) based on any one of the third to seventh aspects. In the eighth aspect, the metallized film (5) further has a margin portion (30) where no metal film (4) is provided. The metal film (4) is in contact with one of the pair of end surface electrodes (7) and is separated from the other of the pair of end surface electrodes (7) via the margin portion (30). The width (W1) of the insulating region (80) is equal to or greater than the width (W2) of the margin portion (30).

[0151] According to this embodiment, it is possible to prevent short circuits caused by the preceding film (2).

[0152] A ninth aspect is a film capacitor (1) based on the eighth aspect. In the ninth aspect, the width (W1) of the insulating region (80) is 0.1 mm or more and 10 mm or less.

[0153] According to this embodiment, the width (W1) of the insulating region (80) is 0.1 mm or more, which further suppresses short circuits caused by the pre-wound film (2). The width (W1) of the insulating region (80) is 10 mm or less, which further improves the heat dissipation of the capacitor element (10).

[0154] A tenth aspect is a film capacitor (1) based on any one of the first to ninth aspects. In the tenth aspect, the heat conductive film (9) contains a metal.

[0155] According to this embodiment, the heat dissipation properties of the capacitor element (10) can be further improved.

[0156] An eleventh aspect is a film capacitor (1) based on any one of the first to tenth aspects. In the eleventh aspect, the thickness of the heat conductive film (9) is greater than the thickness of the metal film (4).

[0157] According to this embodiment, the heat dissipation properties of the capacitor element (10) can be further improved.

[0158] A twelfth aspect is a film capacitor (1) based on any one of the first to eleventh aspects. In the twelfth aspect, the thickness of the thermally conductive film (9) is 1 Å or more and 1000 Å or less.

[0159] According to this embodiment, the thickness of the thermally conductive film (9) is 1 Å or more, which further improves the heat dissipation of the capacitor element (10). The thickness of the thermally conductive film (9) is 1000 Å or less, which makes the film (8) less susceptible to heat damage caused by vapor deposition. The wound body (6) can be easily flattened.

[0160] A thirteenth aspect is a film capacitor (1) based on any one of the first to twelfth aspects. In the thirteenth aspect, a heat conductive film (9) is provided on both sides of the film (8).

[0161] According to this embodiment, the heat dissipation of the capacitor element 10 can be further improved compared to when the heat conductive film 9 is provided on only one side of the film 8. The capacitance of the film capacitor 1 can be increased.

[0162] A fourteenth aspect is a film capacitor (1) based on any one of the first to thirteenth aspects. In the fourteenth aspect, the thickness of the film (8) of the preceding film (2) is greater than the thickness of the dielectric film (3) of the metallized film (5).

[0163] According to this embodiment, the film (8) is less susceptible to heat damage caused by vapor deposition than the dielectric film (3), so that the thermally conductive film (9) can be easily made thicker. [Explanation of symbols]

[0164] 1. Film capacitor 10 Capacitor element 2 Pre-wound film 20 core 3 Dielectric film 30 Margin 4 Metal Film 5 Metallized Film 6 wound body 7 Edge electrode 8 Film 80 Insulation Area 9 Thermal conductive membrane W1 Width of the insulating area W2 Margin width

Claims

1. a core around which a pre-wound film is wound; a metallized film having a dielectric film and a metal film provided on the dielectric film, the metallized film being wound around the winding core; a wound body comprising: a pair of end electrodes provided on both end surfaces of the wound body; A film capacitor having a capacitor element having The pre-wound film has an electrically insulating film and a thermally conductive film provided on the film. Film capacitor.

2. the pre-wound film is electrically insulated between the pair of end electrodes; The film capacitor according to claim 1 .

3. The pre-wound film further has an insulating region where the thermally conductive film is not provided. The film capacitor according to claim 1 .

4. The insulating region extends in the longitudinal direction of the pre-wound film. The film capacitor according to claim 3 .

5. At least a part of the insulating region is present in the width direction center of the pre-wound film. The film capacitor according to claim 3 .

6. the insulating region is located at a position where it contacts one of the pair of end electrodes; The film capacitor according to claim 3 .

7. The insulating region has a triangular wave, a square wave, or a sine wave shape along the longitudinal direction of the pre-wound film. The film capacitor according to claim 3 .

8. the metallized film further has a margin portion where the metal film is not provided, the metal film is in contact with one of the pair of end surface electrodes and is spaced apart from the other of the pair of end surface electrodes via the margin portion, The width of the insulating region is equal to or greater than the width of the margin portion. The film capacitor according to claim 3 .

9. The width of the insulating region is 0.1 mm or more and 10 mm or less. The film capacitor according to claim 8.

10. the thermally conductive film comprises a metal; The film capacitor according to claim 1 .

11. The thickness of the heat conductive film is greater than the thickness of the metal film. The film capacitor according to claim 1 .

12. The thickness of the thermally conductive film is 1 Å or more and 1000 Å or less. The film capacitor according to claim 1 .

13. The heat conductive film is provided on both sides of the film. The film capacitor according to claim 1 .

14. the thickness of the pre-wound film is greater than the thickness of the dielectric film of the metallized film; The film capacitor according to claim 1 .

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