Film Capacitor Element

Abstract

The present invention provides a multilayer film capacitor element which is reduced in capacitance loss. A film capacitor element according to the present invention comprises: a film laminate wherein metal layers having continuous directions different from each other by 180° are stacked, while being alternately reversed; and a first metal electrode and a second metal electrode, which are respectively formed on the pair of end faces of the film laminate. At least one of the pair of end faces of the film laminate in the y direction is provided with a groove part which separates the film laminate and the first metal electrode from each other, while continuously extending in the film stacking direction. The groove part has a configuration that electrically insulates the metal layers, which serve as internal electrodes, and a thermally sprayed metal coating, which serves as an external electrode, from each other.

Description

[Technical field]

[0001] The present disclosure relates to a film capacitor element. [Background technology]

[0002] A film capacitor is formed by winding or stacking a plurality of metallized films in one direction, the metallized films being formed by depositing a metal film serving as an electrode on the surface of a dielectric film made of, for example, polypropylene resin.

[0003] Of these, in the case of laminated film capacitors, when the laminate made of layered metallized films is cut to the required size (capacity), the metal film is cut at the same time as the dielectric film is cut, which can cause insulation failure at the cut surfaces (end faces) where the metal films come into contact with each other.

[0004] Patent Document 1 proposes a configuration for improving the withstand voltage (withstand pressure) of the cut surface of the laminate (element) by providing an insulating margin, which is a groove-shaped or band-shaped exposed portion (gap strip) of the film surface of a constant width where no metal film is formed, that is bent at an angle to the parallel direction in which each insulating margin extends, in the metallized film that constitutes the film capacitor element (core). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5984097 Summary of the Invention

[0006] However, the above Permission The laminated film capacitor described in Patent Document 1 has a large capacitance loss in the vicinity of the cut surface of the film laminate, and therefore a laminated film capacitor element with a small capacitance loss is required. [Means for solving the problem]

[0007] The film capacitor element of the present disclosure includes a rectangular parallelepiped film laminate in which a metal layer is disposed on one surface of the dielectric film, and an edge insulating region that is continuous in a second direction perpendicular to the first direction is provided on one edge of the first direction of the dielectric film, and the orientation of the first direction on the one surface of the dielectric film is inverted by 180° for each sheet so that the planar positions of the edge insulating regions overlap every other sheet, and a first metal electrode and a second metal electrode are formed on each of a pair of end faces of the film laminate in the first direction. The dielectric film having the metal layer electrically connected to at least the first metal electrode has a plurality of strip-shaped metal layers extending in the first direction and a groove-shaped insulating margin extending in the first direction provided between each of the strip-shaped metal layers. The film capacitor element of the present disclosure is characterized in that at least one of a pair of end faces in the second direction of the film laminate has a groove portion that continues in the film stacking direction and separates the film laminate and the first metal electrode. Effect of the Invention

[0008] According to the present disclosure, even when the film laminate is cut in a predetermined direction, a laminated film capacitor element can be obtained in which the loss of capacitance at the cut portion is small. [Brief description of the drawings]

[0009] The objects, features and advantages of the present invention will become more apparent from the following detailed description and drawings. [Figure 1A] 1 is a plan view of a metallized dielectric film showing the configuration of a film capacitor element of an embodiment. [Figure 1B] FIG. 2 is a schematic cross-sectional view of an element showing a laminated state of films. [Figure 1C] FIG. 2 is a plan view of the film capacitor element viewed from above. [Figure 2A] 4 is a cross-sectional view showing a position where a groove is formed in a film capacitor element. FIG. [Figure 2B]4 is a plan view showing the positions at which grooves are formed in the film capacitor element. FIG. [Figure 3A] 13 is a plan view showing another example of a groove portion formed in a film capacitor element. FIG. [Figure 3B] 13 is a plan view showing another example of a groove portion formed in a film capacitor element. FIG. [Figure 3C] 13 is a plan view showing another example of a groove portion formed in a film capacitor element. FIG. [Figure 4A] FIG. 13 is a plan view of a dielectric film with another metal layer pattern. [Figure 4B] FIG. 13 is a schematic cross-sectional view of a film laminate using a dielectric film with another metal layer pattern. [Diagram 5] 1 is an exploded perspective view showing a method for producing a film capacitor element according to an embodiment of the present invention. [Figure 6] FIG. 2 is an external perspective view showing the configuration of the element after films are laminated. [Figure 7] FIG. 2 is an external perspective view showing the configuration of the element after the metal electrodes have been sprayed. [Figure 8] FIG. 13 is an external perspective view showing the configuration of the element after insulating grooves are formed and the positions at which the grooves are formed. [Figure 9] This is an example of an element in which an insulating groove is formed at a different position. [Figure 10] This is an example of an element in which an insulating groove is formed at a different position. [Figure 11] 11 is a plan view showing the configuration of a film capacitor element according to another embodiment of the present disclosure. FIG. [Figure 12] FIG. 11 is a plan view showing the configuration of a film capacitor element according to still another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a film capacitor element according to an embodiment will be described with reference to the drawings.

[0011] The film capacitor element 10 of the embodiment is constructed by alternately laminating multiple dielectric films 1 or 2, each of which has multiple strip-shaped metal layers (films) 3 continuous along a first direction (x-direction in the figure) on the surface of the film, as shown in Figure 1A.

[0012] Each strip-shaped metal layer 3 will become an internal electrode of the capacitor after lamination. The dielectric films 1 and 2 have the same configuration except for the lamination direction after the partial configuration shown in Fig. 1B, but to indicate the orientation after lamination, the strip-shaped metal layers 3 are labeled from the end with 1A to 1N for dielectric film 1 and 2A to 2N for dielectric film 2, as shown in Figs. 1A and 1C.

[0013] In each figure, the continuous direction of the parallel strip metal layers 3 is called the first direction (x direction), and the arrangement direction of the parallel strip metal layers 3 (y direction perpendicular to the x direction) is called the second direction. The lamination direction of the dielectric films 1, 2 is the third direction (z direction in the figure) perpendicular to the first and second directions. Details of the film laminate 4 after lamination will be described later.

[0014] Each strip-shaped metal layer 3 on the surface of the dielectric films 1, 2 is formed by metal deposition on a base film (substrate). Between adjacent strip-shaped metal layers 3 in the y direction, a groove-shaped film surface (hereinafter, insulating margin S), also called a small margin, is exposed, so that each strip-shaped metal layer 3 is electrically independent and insulated from each other.

[0015] Each insulating margin S (small margin) is connected at one end in the first direction (x direction) to a strip-shaped insulating region T called a large margin that continues in the second direction (y direction). The spacing (pitch P) between each insulating margin S is the sum of the width P1 in the y direction of each strip-shaped metal layer 3 and the width P2 in the y direction of each insulating margin S (P=P1+P2).

[0016] The dielectric films 1 and 2 constituting the film capacitor element 10 may be made of organic resin materials such as polypropylene, polyethylene terephthalate, polyarylate, and cycloolefin polymer.

[0017] As shown in Figure 1B, the dielectric films 1 and 2 are stacked by alternately inverting the orientation in the x direction of the dielectric film 1 and the dielectric film 2 adjacent to it above and below (z direction) by 180°, i.e., the dielectric films 1 and 2 are stacked so that the positions of the strip-shaped insulating regions T at the ends (edges) of each dielectric film 1 and 2 are alternately reversed in the x direction to form a film laminate 4.

[0018] Metal electrodes (hereinafter, metallikons) are formed by metal spraying on both ends in the x direction of the film laminate 4. For illustration purposes, one of the metallikons formed on both ends in the x direction is called 5A (first metal electrode) and the other is called 5B (second metal electrode), but these only differ in their positions and there is no difference in their configurations.

[0019] 1C, in the film capacitor element 10 of the embodiment, in the state in which the metallikons 5A and 5B are formed, grooves 11 that separate the strip-shaped metal layer 3 (internal electrode) from the metallikons 5A and 5B (external electrodes) are formed at both ends in the y direction (second direction) of the film capacitor element 10. In this example, two grooves 11 are provided at each end in the x direction of the film laminate 4, for a total of four grooves 11.

[0020] These grooves 11 are formed as continuous concave shapes in the film lamination direction (z direction) in a region including the interface (boundary) between metallikon 5A or 5B and the film laminate 4, or between metallikon 5A or 5B and the film laminate 4. Each groove 11 is provided so as to open toward the end face in the y direction of the film laminate 4, and the groove depth D (y direction) of each groove 11 from the end face in the y direction is greater than the pitch P which is the distance between each of the insulating margins S described above.

[0021] Specifically, in the film capacitor element 10, of the strip metal layers 3 shown in Figure 1C, one or two strip metal layers 3 located at both ends in the y direction of the laminated dielectric film 1, for example, the strip metal layers 3 located at "1A" and "1B" on the left side of the figure and the strip metal layers 3 located at "1N" and "1M" on the right side of the figure, are electrically insulated from the metallikon 5A or 5B by groove portions 11.

[0022] Similarly, in the laminated dielectric film 2, one or two strip-shaped metal layers 3 located at both ends in the y direction, for example, the strip-shaped metal layers 3 located at "2N" and "2M" on the left side (not shown in Figure 1C) and the strip-shaped metal layers 3 located at "2A" and "2B" on the right side (not shown), are electrically insulated from the metallikon 5A or 5B by groove portions 11.

[0023] That is, when a film capacitor is produced using the film capacitor element 10 having the above configuration, each strip-shaped metal layer 3 is linear in the x direction, and the number of strip-shaped metal layers 3 that are cut and insulated at both ends in the y direction is small. Therefore, the film capacitor of the embodiment has reduced capacitance loss near the cut surfaces (both ends in the y direction) after lamination, compared to conventional film capacitors using elements having insulating margins of a bent pattern (see Patent Document 1).

[0024] The groove depth D of each groove 11 from the end face in the y direction is sufficient if one or two strip-shaped metal layers 3 located at both ends in the y direction are cut and insulated. Therefore, the groove depth D of each groove 11 may be about 1.0 times (Dmin in the figure) to 3.0 times (Dmax in the figure) the pitch P of the insulation margin S, as shown in the upper right of Fig. 1A. This makes it possible to reliably insulate at least one strip-shaped metal layer 3 located at both ends in the y direction, regardless of the width of the strip-shaped metal layer 3 located at the end in the y direction, that is, in this example, the y-direction width P1 of 1A, 2A or 1N, 2N that varies due to cutting of the film laminate 4.

[0025] The formation positions of the grooves 11 in the x direction (first direction) (FIG. 2A) are related to the internal structure of the film laminate 4 and will be described later.

[0026] 5 to 8 are diagrams for explaining the process of manufacturing the film capacitor element of the embodiment. In the second embodiment shown in Figs. 5 to 8 and its modified examples shown in Figs. 9 and 10, similar to Fig. 1, the continuous direction of the parallel strip metal layers 3 is the first direction (x direction in the figures), the arrangement direction of the parallel strip metal layers 3 (y direction perpendicular to the x direction) is the second direction, and the lamination direction of the film perpendicular to the first and second directions is the third direction (z direction in the figures).

[0027] In producing a laminated film capacitor element 70, first, as shown in Figure 5, multiple dielectric films 1 or 2 having multiple continuous strip-shaped metal layers 3 along the x-direction on the surface of the film are stacked while alternating the orientation in the x-direction, i.e., while reversing the orientation in the x-direction (first direction) for each film by 180° so that the planar positions of the strip-shaped insulating regions T overlap every other film.

[0028] As mentioned above, the dielectric films 1 and 2 have the same structure, except that their orientation in the x direction is reversed. The lamination can be performed by a conventional method, such as stacking the long dielectric films 1 and 2 on top of each other and winding them around a cylinder or a tube with a polygonal cross section. The imaginary line (two-dot chain line) in Fig. 5 indicates the cutting line after winding around a tube or the like.

[0029] Fig. 6 is a view of the film laminate 4 after being cut to a predetermined length, viewed from the cut surface (y-direction end surface). As shown in Fig. 6, the vertically adjacent dielectric films 1 and 2 are laminated in a state where they are slightly shifted (offset) in the continuous direction (x-direction) of the strip-shaped metal layers 3, so that the edges of each strip-shaped metal layer 3 are exposed or adjacent to both end surfaces of the film laminate 4 in the x-direction.

[0030] In addition, an insulating layer 12, which also serves as a protective layer (film) for the laminate, such as a dielectric film not formed with the strip-shaped metal layer 3, is laminated on the upper surface of the film laminate 4 of the embodiment. The insulating layer 12 may be omitted.

[0031] 7, a first metal electrode and a second metal electrode (metallikon 5A, 5B) are formed by metal spraying on both end faces in the x direction of the film laminate 4 where the edges of each of the previously described strip-shaped metal layers 3 are exposed. As a result, each strip-shaped metal layer 3 on the dielectric films 1, 2 is electrically connected to the metallikon on either the left or right side in the figure (x direction) and functions as an internal electrode of the element.

[0032] Next, in the film capacitor element 70 of the second embodiment, grooves 11 (groove depth D in the y direction) that open toward both end faces in the y direction of the film laminate 4, which are the cut surfaces of the laminate (wound body), are formed at positions that separate the strip-shaped metal layer 3 (internal electrode) from the metallikon 5A, 5B (external electrodes). In this example, a total of four grooves 11 are provided, two on each end in the y direction.

[0033] The groove portion 11 can be formed into a shape that continues in the stacking direction (z direction) by machining, cutting, etc. It may also be formed into a shape called a notch, slit, notch, or the like.

[0034] Moreover, the groove depth D of the groove portion 11 in the y direction should be larger than the pitch P, which is the spacing between the strip-shaped metal layers 3 and the spacing between the insulating margins S. Specifically, the depth should be about 1.0 to 3.0 times the pitch P so that one or two strip-shaped metal layers 3 located at both ends in the y direction are insulated. If the depth exceeds 3.0 times the pitch P, the capacitance loss at the ends increases, so it is preferable to keep it below that.

[0035] Furthermore, the position where the groove portion 11 in the x direction is formed may be between the metallikon 5A or 5B and the film laminate 4 as in a film capacitor element 70 shown in Fig. 8, or may be formed in a region including the interface (boundary) between the metallikon 5A or 5B and the film laminate 4 as in a film capacitor element 80 shown in Fig. 9. Furthermore, as in a film capacitor element 90 shown in Fig. 10, both groove portions 11 may be formed on the film laminate 4 side of the interface (boundary) between the metallikon 5A or 5B and the film laminate 4.

[0036] Either of the configurations can achieve the same effect. Only the strip-shaped metal layer 3 on the dielectric film 1 or the strip-shaped metal layer 3 on the dielectric film 2 is exposed on the inner surface (inner wall surface) of the groove 11, and each groove 11 is formed at a position spaced a distance Q in the x direction from an end 31 on the dielectric film 1 or an end 32 on the dielectric film 2 of the other strip-shaped metal layer 3 that is not exposed on the inner surface of the groove 11 and is located inside the groove 11, as shown in Fig. 2A.

[0037] 2B is a plan view showing the x-direction formation positions of these grooves 11 as viewed from above the film capacitor element 20. As shown in the lower half of this figure, the aforementioned grooves 11 are located on the outer side (metallicon 5) of the film laminate 4, which is located on the inner side in the x-direction of the film laminate 4, with a distance Q between them and the end 31 of the strip-shaped metal layer 3 on the dielectric film 1. B This provides reliable electrical insulation from the internal electrodes (strip metal layer 3). The distance Q between the ends 31, 32 of the strip metal layer 3 may be set to 200 μm or more.

[0038] In addition, Figure 1 A~ 2 B8 to 10, two grooves 11 are provided at each of the ends in the y direction and the x direction, making a total of four grooves 11, but as shown in FIGS. 3A to 3C, one groove 11 may be provided at each of the ends in the y direction between the film laminate 4 and the metallikon 5A or 5B, making a total of two grooves 11. In this case, the two grooves 11 may be provided at different ends (corners) in the x direction that are diagonal on the xy plane of the film capacitor element 30, or may be provided at the y direction ends (corners) on either one side in the x direction. Furthermore, although not shown, three grooves 11 may be provided in total, two at the ends in the y direction between the film laminate 4 and the metallikon 5A, and one at the ends in the y direction between the film laminate 4 and the metallikon 5B.

[0039] In addition, when the film laminate 4 is formed by alternately stacking a dielectric film 1 (see FIG. 1A) having a strip-shaped metal layer 3 divided by an insulating margin S and a dielectric film 13 (see FIG. 4A) having a full-surface metal layer 3' in a so-called solid pattern without an insulating margin, as shown in FIG. 4B, the groove 11 may be disposed at the y-direction end (corner) on the right side in the x-direction so that a gap is provided between the end 33 of the full-surface metal layer 3' and the metallikon 5A, as shown in FIG. 4B. In FIG. 4B, each strip-shaped metal layer 3 on the dielectric film 1 is electrically connected to the metallikon 5A (first metal electrode) on the right side in the figure (x-direction), and the full-surface metal layer 3' on the dielectric film 13 is connected to the metallikon 5B (second metal electrode).

[0040] In this way, the number and positions of grooves 11 can be changed depending on the arrangement and arrangement pattern of the metal film that becomes the internal electrode, as in film capacitor elements 30, 40, 50 shown in Figures 3A to 3C or film capacitor element 60 in Figures 4A and 4B. Film capacitors using film capacitor elements 30, 40, 50, 60 having grooves 11 with a changed number and position also achieve the same effects and functions as film capacitors using film capacitor elements 10, 20, 70, 80, 90 described above.

[0041] FIG. 11 is a plan view showing the configuration of a film capacitor element 100 according to another embodiment of the present disclosure. The same reference numerals are used for parts corresponding to the above-mentioned embodiments. The film capacitor element 100 according to this embodiment includes a rectangular parallelepiped film laminate 4 in which a strip-shaped metal layer 3 is disposed on one surface, and a strip-shaped insulating region T is provided on one edge of the first direction x of the one surface, the strip-shaped insulating region T being continuous in a second direction y perpendicular to the first direction x, is laminated in a plurality of sheets by inverting the orientation of the first direction x on one surface by 180° for each sheet so that the planar positions of the strip-shaped insulating region T overlap every other sheet, and a metallikon 5A as a first metal electrode and a metallikon 5B as a second metal electrode formed on each of a pair of end faces of the film laminate 4 in the first direction x. The constituent material of the dielectric films 1 and 2 constituting the film capacitor element 100 may be formed from an organic resin material such as polypropylene, polyethylene terephthalate, polyarylate, or cycloolefin polymer, as in the above-mentioned embodiments.

[0042] The dielectric films 1, 2 having metal layers at least a portion of which is electrically connected to the metallikons 5A, 5B, respectively, have a plurality of strip-shaped metal layers 3 extending in a first direction x, and groove-shaped insulating margins S extending in the first direction x provided between each strip-shaped metal layer 3. A pair of end faces of the film laminate 4 in the second direction y have groove portions 11 continuing in the film lamination direction z, which separate the film laminate 4 from each of the metallikons 5A, 5B.

[0043] In such a film capacitor element 100, the insulating margins S between the strip-shaped metal layers 3 are formed at intervals ΔL1 from the metallikons 5A and 5B in the first direction x. The insulating margins S may not be connected to the metallikons 5A and 5B and may be interrupted partway within the range in which the strip-shaped metal layers 3 and the metallikons 5A and 5B are separated by the grooves 11, that is, within the groove depth D in the second direction y of the grooves 11. In this case, in the example of FIG. 11, the strip-shaped metal layers 3 located at reference marks 1C, 1D, to, 1K, and 1L; 2C, 2D, to, 2K, and 2L are connected to each other in the region in which the insulating margins S are separated from the metallikons 5A and 5B at intervals ΔL1. Therefore, as long as each strip-shaped metal layer 3 located in the intermediate portion between each groove portion 11 in the y direction is at least partially connected to the metallikon 5A or 5B, each strip-shaped metal layer 3 located in the intermediate portion is commonly connected to the metallikon 5A or 5B. This prevents a decrease in the overall capacitance even if a connection failure occurs between the multiple strip-shaped metal layers 3 located in the intermediate portion and each metallikon 5A or 5B.

[0044] 12, even if a groove portion 11 is formed in a region including the interface (boundary) between the metallikon 5A or 5B and the film laminate 4, the strip-shaped metal layers 3 located at the reference marks 1C, 1D, . . . 1K, 1L; 2C, 2D, . . . 2K, 2L have an insulating margin S spaced apart from the metallikon 5A or 5B by a distance ΔL, as in the embodiment shown in FIG. 11 described above. 2 The strip-shaped metal layers 3 located in the intermediate portions between the groove portions 11 in the y direction have strip-shaped metal layers 3 that are electrically connected to the metallikons 5A, 5B at least in part, so that even if poor connection occurs between the multiple strip-shaped metal layers 3 located in the intermediate portions and each of the metallikons 5A or 5B, a decrease in the overall capacitance is prevented.

[0045] In the film capacitor element having the above configuration, one or two strip-shaped metal layers 3 located at both ends in the y direction (second direction) are separated from the metallikon 5A or 5B by the grooves 11 and are electrically insulated. That is, compared with conventional film capacitors using elements having an insulating margin of a bent pattern, the capacitance loss near the cut surfaces (both ends in the y direction) after lamination is reduced. Therefore, film capacitors using these film capacitor elements can be laminated film capacitors with little capacitance loss at the cut portions.

[0046] The present invention can be implemented in various other forms without departing from its spirit or main characteristics. Therefore, the above-described embodiment is merely an example in all respects, and the scope of the present invention is indicated in the claims and is not limited in any way by the text of the specification. Furthermore, all modifications and changes falling within the scope of the claims are within the scope of the present invention. [Explanation of symbols]

[0047] 1,2,13 Dielectric film 3 metal layer 4 Film laminate 5A, 5B Metallicon (metal electrode) 10 Film capacitor element 11 Groove S Insulation margin T Strip insulation area

Claims

[Claim 1] a rectangular parallelepiped film laminate in which a plurality of dielectric films are laminated, each of which has a metal layer disposed on one surface thereof and an edge insulating region provided on one edge of the first direction of the first surface, the edge insulating region being continuous in a second direction perpendicular to the first direction, the first direction being inverted by 180° for each film so that the planar positions of the edge insulating regions of every other film overlap; a first metal electrode and a second metal electrode formed on each of a pair of end faces in the first direction of the film laminate, the dielectric film having the metal layer electrically connected to at least the first metal electrode has a plurality of strip-shaped metal layers extending in the first direction, and groove-shaped insulating margins extending in the first direction provided between the strip-shaped metal layers, a spacing between the insulating margins is a value obtained by adding a width of the strip metal layer in the second direction and a width of the insulating margin in the second direction, a groove portion that is continuous in a film stacking direction and separates the film stack from the first metal electrode, on at least one of a pair of end faces of the film stack in the second direction; a groove depth of the groove portion in the second direction is greater than a width of each of the strip-shaped metal layers in the second direction; A film capacitor element, wherein the groove portion is arranged to open toward the end face in the second direction of the film laminate, and the groove depth of the groove portion from the end face in the second direction is greater than the spacing of the insulating margin.

Images