Film capacitor

Abstract

This film capacitor comprises a capacitor element 10 which includes an element body 20 having a first end surface 21 and a second end surface 22 positioned at both ends in a length direction and a side surface 23 connecting the first end surface 21 and the second end surface 22, a first external electrode 31 provided on the first end surface 21 of the element body 20, and a second external electrode 32 provided on the second end surface 22 of the element body 20, a first lead-out terminal 61 which comprises a first resin member 71 disposed so as to surround a part of the outer periphery of the first lead-out terminal 61, and which is connected to the first external electrode 31, a second lead-out terminal 62 which comprises a second resin member 72 disposed so as to surround a part of the outer periphery of the second lead-out terminal 62, is connected to the second external electrode 32, and is routed to the first external electrode 31 side along the side surface 23 of the element body 20, and an exterior body 40 which is made of a laminate film 40 including a resin layer, seals the capacitor element 10 such that the resin layer is disposed around the capacitor element 10, and has a welded portion 42 where a first part 42 and a second part 42, which are parts of the resin layer located in opposing positions, are welded together, wherein: the welded portion includes a first lead-out port 51, which is a part where the first part and the second part are welded to each other with the first resin member 71 interposed therebetween, and a second lead-out port 52, which is a part where the first part and the second part are welded to each other with the second resin member 72 interposed therebetween; the first external electrode 31 and the second lead-out terminal 62 are insulated from each other by the second resin member 72; and the tip end of the first lead-out terminal 61 and the tip end of the second lead-out terminal 62 project from the same side edge of the exterior body 40.

Description

Film capacitor

[0001] This invention relates to a film capacitor.

[0002] Film capacitors with laminate film casings are small and resistant to high humidity environments, and are in high demand in the automotive market. This type of film capacitor has a structure in which a capacitor element is fabricated by winding a dielectric film, a protective film is wrapped around the surface of the capacitor element, and the capacitor element with the protective film wrapped around it is sealed inside an outer casing made of laminate film.

[0003] Patent Document 1 discloses a film capacitor using a laminate film for its exterior, in which the lead terminals are drawn out in opposite directions from both ends of the capacitor element. Furthermore, in this configuration, a method is employed to heat-weld the lead terminals to a polypropylene resin as an insulating resin in order to improve the adhesion between the lead terminals and the laminate film and to improve moisture resistance.

[0004] International Publication No. 2024 / 070067

[0005] Film capacitors used in automotive applications are connected to inverters, and there is a growing expectation for semiconductors used in inverters to shift from power semiconductors such as Si to materials with high switching frequencies such as GaN. Accordingly, film capacitors are required to reduce ESL (Electron Sloshing Limit) to handle large currents in the high-frequency range.

[0006] One method for reducing ESL (Electromagnetic Spread Limiting) is to have the lead terminals of the capacitor elements lead out in the same direction. By doing so, the magnetic fields generated from the two lead terminals can cancel each other out, thereby reducing the inductance of the film capacitor.

[0007] In order to draw out the lead terminals of a capacitor element in the same direction, it is necessary to prevent the lead terminal connected to one electrode (positive terminal) of the capacitor element from coming into contact with the other electrode (negative terminal).

[0008] The present invention has been made to solve the above problems and aims to provide a film capacitor in which ESL can be reduced and two lead terminals are drawn out from the laminate film in the same direction while being insulated from each other.

[0009] The film capacitor of the present invention comprises a capacitor element including an element body having first and second end faces located at both ends in the longitudinal direction, and a side surface connecting the first and second end faces; a first external electrode provided on the first end face of the element body; and a second external electrode provided on the second end face of the element body; a first resin member arranged to surround a part of its outer circumference and connected to the first external electrode and comprising a first lead terminal; a second resin member arranged to surround a part of its outer circumference and connected to the second external electrode and routed along the side surface of the element body toward the first external electrode and comprising a laminate film including a resin layer The capacitor element is sealed such that the resin layer is arranged around the capacitor element, and the outer casing has a welded portion where a first portion and a second portion, which are opposing parts of the resin layer, are welded together, wherein the welded portion includes a first outlet, which is the location where the first portion and the second portion are welded together via the first resin member, and a second outlet, which is the location where the first portion and the second portion are welded together via the second resin member, the first external electrode and the second lead terminal are insulated by the second resin member, and the tip of the first lead terminal and the tip of the second lead terminal protrude from the same side of the outer casing, the film capacitor.

[0010] According to the present invention, it is possible to reduce ESL and provide a film capacitor in which two lead terminals are drawn out from the laminate film in the same direction while being insulated from each other.

[0011] Figure 1 is a schematic perspective view showing an example of a film capacitor according to the present invention. Figure 2 is an exploded view of the film capacitor shown in Figure 1. Figure 3 is a schematic perspective view showing the film capacitor shown in Figure 1 with the laminate film removed. Figure 4 is a cross-sectional view taken along line A-A in Figure 1, showing a cross-section including the first lead terminal and the first resin member. Figure 5 is a cross-sectional view taken along line B-B in Figure 1, showing a cross-section including the second lead terminal and the second resin member. Figure 6 is a schematic perspective view showing an example of a wound-type capacitor element. Figure 7 is a cross-sectional view taken along line C-C of the capacitor element shown in Figure 6. Figure 8 is a schematic perspective view showing an example of the first and second metallized films constituting the element body of the capacitor element shown in Figures 6 and 7.

[0012] The film capacitor of the present invention will now be described. The present invention is not limited to the following configurations, and can be modified and applied as appropriate without altering the essence of the invention. Furthermore, combinations of two or more of the preferred configurations described below also constitute the present invention.

[0013] In this specification, terms describing relationships between elements (e.g., "perpendicular," "parallel," "orthogonal," etc.) and terms describing the shape of elements do not necessarily represent only strict meanings, but rather include a range of substantially equivalent terms, such as differences of a few percent. Furthermore, the drawings shown below are schematic diagrams, and their dimensions, aspect ratios, etc., may differ from those of the actual product.

[0014] Figure 1 is a schematic perspective view showing an example of a film capacitor according to the present invention. Figure 2 is an exploded view of the film capacitor shown in Figure 1.

[0015] The film capacitor of the present invention includes an outer casing made of a laminate film containing a resin layer. The outer casing seals the capacitor element such that the resin layer is arranged around the capacitor element. The laminate film has a welded portion in which two opposing portions of the resin layer, a first portion and a second portion, are welded together.

[0016] The film capacitor 1 shown in Figures 1 and 2 includes a capacitor element 10 and a laminate film 40 that covers the periphery of the capacitor element 10. The laminate film 40 is formed by bonding together a pair of upper and lower laminate materials 41 that cover the capacitor element 10. The laminate materials 41 are shaped to conform to the outer shape of the capacitor element 10, and for example, have a flange portion 42 on their outer edge. The pair of laminate materials 41 are heat-sealed together at the flange portion 42 to form the laminate film 40.

[0017] Each flange portion 42 of the pair of laminate materials 41 corresponds to a welded portion where the first and second portions, which are opposing parts of the resin layer, are welded together.

[0018] The flange portion 42 of the laminate film 40 has an outlet for pulling out the lead terminals. The outlets are a first outlet 51 and a second outlet 52, which are provided on the same side of the laminate film 40. The tip of the first lead terminal 61 protrudes from the first outlet 51, and the tip of the second lead terminal 62 protrudes from the second outlet 52.

[0019] The laminate film 40 has a resin layer as its innermost layer and is made of a material that can be welded to the first resin member and the second resin member described later. Furthermore, it is not particularly limited as long as the material can be heat-sealed to the laminate films at the welding portion. The laminate film only needs to have a resin as its innermost layer, and may be a single-layer resin film or a multi-layer resin film. The resin of the innermost layer is preferably a polyolefin-based thermoplastic resin, such as polypropylene resin.

[0020] When the laminate film is a multilayer film, it may be a multilayer film having a metal film, or a multilayer film having a layer configuration of a first resin layer / metal film / second resin layer. In this case, the first resin layer is the innermost layer.

[0021] When the laminate film is a multilayer film having a layer structure of a first resin layer / metal film / second resin layer, the first resin layer is preferably a polyolefin-based thermoplastic resin, such as polypropylene resin. The thickness of the first resin layer is preferably 20 μm or more and 150 μm or less.

[0022] The metal film is a layer that improves the barrier properties against moisture, and is preferably made of a metal vapor-deposited film. Furthermore, the metal film is preferably made of a metallic material such as aluminum. The thickness of the metal film is preferably 20 μm or more and 50 μm or less.

[0023] The second resin layer is a layer for improving moisture barrier properties and protecting the metal film, and is preferably composed of a resin material such as nylon resin or polyethylene terephthalate resin. Furthermore, the thickness of the second resin layer is preferably 10 μm or more and 40 μm or less.

[0024] When the laminate film is a multilayer film having a layer structure of a first resin layer / metal film / second resin layer, for example, it can have a structure such as polypropylene resin (12 μm) / aluminum film (40 μm) / polyethylene terephthalate resin (80 μm).

[0025] In the film capacitor of the present invention, the overall thickness of the laminate film is preferably 80 μm or more and 200 μm or less, and more preferably 100 μm or more and 160 μm or less. If the thickness of the laminate film is less than 80 μm, the strength of the laminate film will be low and it will be easily damaged. If the thickness of the laminate film exceeds 200 μm, the processability of the laminate film may deteriorate. In addition, the overall size of the film capacitor tends to increase, making it difficult to miniaturize products using the film capacitor.

[0026] Figure 3 is a schematic perspective view showing the film capacitor shown in Figure 1 with the laminate film (outer casing) removed. The capacitor element 10 includes an element body 20 having a first end face 21 and a second end face 22 located at both ends in the longitudinal direction (indicated by the double-headed arrow L in Figure 3), and a side surface 23 connecting the first end face 21 and the second end face 22; a first external electrode 31 provided on the first end face 21 of the element body 20; and a second external electrode 32 provided on the second end face 22 of the element body 20.

[0027] As shown in Figure 3, the element body 20 has a columnar shape overall, with, for example, the first end face 21 and the second end face 22 having a racetrack-like shape. Furthermore, the side surface 23 of the element body 20 has a planar portion 23s. １ And the curved portion 23s that is formed in a curved shape. ２ It is composed of the above. Furthermore, the surface of the side surface 23 of the element body 20 may be the surface of a wound body around which a metallized film, described later, is wound, or it may be the surface of an insulating protective film covering the surface of the wound body.

[0028] The first external electrode 31 is, for example, plate-shaped and covers the first end face 21 of the element body 20. The first external electrode 31 also has an end face 31e that is visible when the first external electrode 31 is viewed from the longitudinal direction L, and a side surface 31s that is visible when the first external electrode 31 is viewed from the longitudinal direction L. The shape of the end face 31e of the first external electrode 31 in plan view is racetrack-shaped.

[0029] The second external electrode 32 is, for example, plate-shaped and covers the second end face 22 of the element body 20. The second external electrode 32 also has an end face 32e that is visible when the second external electrode 32 is viewed from above along its length L, and a side surface 32s that is visible when the second external electrode 32 is viewed from above from a direction perpendicular to its length L. The plan view shape of the end face 32e of the second external electrode 32 is racetrack-shaped.

[0030] The configuration of the first lead terminal and its surroundings will be described with reference to Figures 3 and 4. Figure 4 is a cross-sectional view taken along line A-A in Figure 1, showing a cross-section including the first lead terminal and the first resin member. The location of the cross-sectional view taken along line A-A is also shown in Figure 3.

[0031] The first lead terminal 61 is a flat terminal electrode. The first lead terminal 61 is directly and physically connected to the first external electrode 31 and protrudes from the first external electrode 31. The first lead terminal 61 is also electrically connected to the first external electrode 31. Preferably, the first lead terminal 61 is welded to the first external electrode 31. The fact that the first lead terminal 61 protrudes from the first external electrode 31 means that the first lead terminal 61 extends in a direction normal to the end face 31e of the first external electrode 31.

[0032] The first lead terminal 61 is provided with a first resin member 71 that surrounds a part of its outer circumference. Specifically, the first resin member 71 is provided at the base of the position where the first lead terminal 61 protrudes from the outer casing 40. The first resin member 71 is made of resin and is made of a material that can be welded to the innermost resin layer of the laminate film. It is also made of an electrically insulating material. The first resin member 71 is provided at the base of the position where it protrudes from the outer casing 40, and is positioned to correspond to the position and shape of the first lead outlet 51 (see Figure 2) provided on the flange portion 42 of the laminate film 40.

[0033] As shown in Figure 4, the first resin member 71 is heat-sealed to the flange portion 42 of the laminate film 40 at the first outlet 51, and also fixes the first outlet terminal 61. In other words, the welded portion of the outer casing 40 has the first outlet 51, which is the location where the first and second portions of the resin layer are welded together via the first resin member 71.

[0034] The second lead terminal and its surrounding configuration will be described with reference to Figures 3 and 5. Figure 5 is a cross-sectional view along line B-B in Figure 1, showing the cross-section including the second lead terminal and the second resin member. The location of the cross-sectional view along line B-B is also shown in Figure 3.

[0035] The second lead terminal 62 is a flat terminal electrode having a first end 62a and a second end 62b located at both ends, and is connected to the second external electrode 32 at its first end 62a. Preferably, the second lead terminal 62 is welded to the second external electrode 32. The second lead terminal 62 is located on the flat portion 23s of the side surface 23 of the element body 20.１ It is routed along this line towards the first external electrode 31.

[0036] The second lead terminal 62 is provided with a second resin member 72 that surrounds a portion of its outer circumference. Specifically, the second resin member 72 is provided between the second lead terminal 62 and the first external electrode 31, and at the base of the position where the second lead terminal 62 protrudes from the outer casing 40. The second resin member 72 is made of resin and is made of a material that can be welded to the innermost resin layer of the laminate film. It is also made of an electrically insulating material.

[0037] The second resin member 72 is in contact with the side surface 31s and end surface 31e of the first external electrode 31, and is provided between the side surface 31s of the first external electrode 31 and the second lead terminal 62, and between the end surface 31e of the first external electrode 31 and the second lead terminal 62. Because the second resin member 72 is provided in this position, the second lead terminal 62 is not physically connected to the first external electrode 31, nor is it electrically connected.

[0038] Furthermore, the second resin member 72 is positioned at the base of the part that protrudes from the outer casing 40, and is provided in a manner that corresponds to the position and shape of the second outlet 52 (see Figure 2) provided on the flange portion 42 of the laminate film 40.

[0039] As shown in Figure 5, the second resin member 72 is heat-sealed to the flange portion 42 of the laminate film 40 at the second outlet 52, and also fixes the second outlet terminal 62. In other words, the welded portion of the outer casing 40 has a second outlet 52, which is the location where the first and second portions of the resin layer are welded together via the second resin member 72.

[0040] Furthermore, the second resin member 72 may be positioned on the side surface 23 of the element body 20, between the second lead terminal 62 and the side surface 23 of the element body 20, along the direction from the first external electrode 31 toward the second external electrode 32, starting from the first external electrode 31. In this case, the length of the second resin member 72 along the direction from the first external electrode 31 toward the second external electrode 32 on the side surface 23 of the element body 20 (indicated by the double arrow L in Figures 3 and 5) is... ７２It is preferable that the length (shown by ) is equal to or greater than the minimum space distance defined in JIS C 60664-1. When the length of the second resin member 72 at the above position is equal to or greater than a value that satisfies the above standard, the first external electrode 31 and the second lead-out terminal 62 can be more reliably insulated. However, the length of the second resin member 72 at the above position may be equal to or less than a value that satisfies the above standard.

[0041] If the surface of the side surface 23 of the element body 20 is the surface of an insulating protective film, even if the second lead-out terminal 62 contacts the side surface 23 of the element body 20, the insulation between the second lead-out terminal 62 and the element body 20 is maintained. Therefore, it is sufficient to provide the second resin member 72 only in a part of the side surface 23 of the element body 20, in the vicinity of the first external electrode 31.

[0042] On the other hand, when no protective film is provided on the surface of the side surface 23 of the element body 20, if the second lead-out terminal 62 contacts the side surface 23 of the element body 20, the insulation between the second lead-out terminal 62 and the element body 20 may not be maintained. Therefore, in the entire region from the first external electrode 31 to the second external electrode 32 on the side surface 23 of the element body 20, it is preferable to dispose the second resin member 72 between the second lead-out terminal 62 and the side surface 23 of the element body 20 along the direction from the first external electrode 31 to the second external electrode 32 starting from the first external electrode 31.

[0043] The thicknesses of the first resin member and the second resin member are preferably 0.02 mm or more and 0.3 mm or less, respectively. Hereinafter, when the first resin member and the second resin member are not distinguished, they are referred to as "resin member". When the thickness is 0.02 mm or more, sufficient insulation can be ensured by the resin member. In particular, since the second resin member has the role of ensuring the insulation between the first external electrode and the second lead-out terminal, it is effective to set its thickness to 0.02 mm or more. Also, if the thickness of the resin member is too thick, gaps may occur when the first part and the second part of the laminate film are welded to the resin member, and the sealing property may become insufficient. Also, if the thickness of the resin member is too thick, water intrusion from the resin member is likely to occur. From these viewpoints, the thickness of the resin member is preferably 0.3 mm or less.

[0044] The tips of the first and second lead terminals protrude from the same side of the casing. The distance W between the protruding first and second lead terminals. ６０ It is preferable that the spacing between the capacitor elements in the width direction (indicated by double arrows W in Figure 3) is 50 mm or less. The smaller the spacing between the first and second lead terminals, the lower the ESL can be. On the other hand, if this spacing is too small, there is a risk of a short circuit between the first and second lead terminals. Therefore, the spacing between the first and second lead terminals is determined considering the voltage applied to the capacitor elements and the degree of contamination. Also, the protrusion length of the second resin member from the second lead outlet (indicated by double arrows D in Figures 1 and 5) is also important. ７２ It is preferable that the (indicated by) is 5.15 mm or more. When this protruding length is 5.15 mm or more, it prevents current from being supplied to the second lead terminal through the metal film exposed at the cut surface of the laminate film.

[0045] Figure 3 shows the length L, width W, and height T of the capacitor element. In the film capacitor of the present invention, it is preferable that the length dimension of the capacitor element is 60 mm or less. This is because a shorter length dimension of the capacitor element reduces the length of the second lead terminal routed along the side of the element body, thereby reducing ESL (Electromagnetic Slip Limit).

[0046] The film capacitor of the present invention achieves an ESL reduction effect by having the first and second lead terminals protrude from the same side of the outer casing, thereby bringing the first and second lead terminals into close proximity. Furthermore, since the space between the second lead terminal and the first external electrode is insulated by the second resin member, the function as a capacitor is maintained. In addition, since the innermost layer of the laminate film is welded to the first and second resin members, sealing with the laminate film is suitable, and barrier properties against moisture are maintained.

[0047] In the capacitor element used in the film capacitor of the present invention, the element body may be a wound-type film capacitor in which metallized films are wound in a laminated state, or it may be a laminated-type film capacitor in which metallized films are laminated.

[0048] The following description will focus on the case where the element body is a wound-type film capacitor in which metallized films are wound in a laminated state. Figure 6 is a schematic perspective view showing an example of a wound-type capacitor element. Figure 7 is a cross-sectional view taken along the C-C line of the capacitor element shown in Figure 6.

[0049] In the capacitor element 10 shown in Figures 6 and 7, the element body 20 is a laminate including a first metallized film 81 and a second metallized film 82. The element body 20 is a wound body in which the first metallized film 81 and the second metallized film 82 are laminated and wound together. A pair of external electrodes, a first external electrode 31 and a second external electrode 32, are electrically connected to the end face of the element body 20.

[0050] As shown in Figure 7, the first metallized film 81 comprises a first dielectric film 83 and a first metal layer 85 provided on the surface of the first dielectric film 83, and the second metallized film 82 comprises a second dielectric film 84 and a second metal layer 86 provided on the surface of the second dielectric film 84.

[0051] As shown in Figure 7, the first metal layer 85 and the second metal layer 86 face each other with the first dielectric film 83 or the second dielectric film 84 in between. Furthermore, the first metal layer 85 is electrically connected to the first external electrode 31, and the second metal layer 86 is electrically connected to the second external electrode 32.

[0052] The first dielectric film 83 and the second dielectric film 84 may each have different configurations, but it is preferable that they have the same configuration.

[0053] The first metal layer 85 is formed such that it reaches one side edge on one surface of the first dielectric film 83 but not the other side edge. On the other hand, the second metal layer 86 is formed such that it does not reach one side edge on one surface of the second dielectric film 84 but reaches the other side edge. The first metal layer 85 and the second metal layer 86 are made of, for example, an aluminum layer.

[0054] Figure 8 is a schematic perspective view showing an example of the first and second metallized films that constitute the element body of the capacitor element shown in Figures 6 and 7.

[0055] As shown in Figures 7 and 8, the first dielectric film 83 and the second dielectric film 84 are stacked with a widthwise offset (left-right in Figure 7) from each other, such that the end of the first metal layer 85 that reaches the side edge of the first dielectric film 83, and the end of the second metal layer 86 that reaches the side edge of the second dielectric film 84, are both exposed from the stacked film. As shown in Figure 8, the element body 20 is wound with the first dielectric film 83 and the second dielectric film 84 stacked, forming a wound metallized film, with the first metal layer 85 and the second metal layer 86 remaining exposed at their ends and stacked.

[0056] In Figures 7 and 8, the second dielectric film 84 is wound on the outside of the first dielectric film 83, and the first metal layer 85 and the second metal layer 86 are wound on each of the first dielectric film 83 and the second dielectric film 84, respectively, so that they face inward.

[0057] The winding of the metallized film may be equipped with a cylindrical winding shaft. The winding shaft is positioned on the central axis of the wound metallized film and serves as the winding shaft when winding the metallized film.

[0058] When such a rolled metallized film is pressed flat from above and below, the end face becomes racetrack-shaped, and the overall shape becomes a columnar element body.

[0059] The external electrodes are formed by thermal spraying, for example, zinc, onto each end face of the element body 20 obtained as described above. The first external electrode 31 contacts the exposed end of the first metal layer 85, thereby electrically connecting with the first metal layer 85. The second external electrode 32 contacts the exposed end of the second metal layer 86, thereby electrically connecting with the second metal layer 86.

[0060] It is preferable to provide an insulating protective film on the side surface of the element body, or on the side surface of a capacitor element on which external electrodes are formed.

[0061] In the film capacitor of the present invention, the dielectric film constituting the element body of the capacitor element may contain a curable resin as its main component, or it may contain a thermoplastic resin as its main component. From the viewpoint of improving the heat resistance of the film capacitor, it is preferable that the dielectric film contains a curable resin as its main component.

[0062] In this specification, "main component of the dielectric film" means the component with the largest weight percentage, preferably the component with a weight percentage exceeding 50% by weight. Therefore, the dielectric film may also contain components other than the main component, such as additives like silicone resin, and uncured portions of starting materials such as the first organic material and the second organic material described later.

[0063] The curable resin may be a thermosetting resin or a photocurable resin.

[0064] In this specification, "thermosetting resin" means a resin that can be cured by heat, and does not limit the curing method. Therefore, as long as it is a resin that can be cured by heat, resins cured by methods other than heat (e.g., light, electron beam, etc.) are also included as thermosetting resins. Furthermore, in some cases, the reaction may be initiated by the reactivity of the material itself, and resins that proceed to cure without necessarily being subjected to external heat or light are also considered thermosetting resins. The same applies to photocurable resins, and does not limit the curing method.

[0065] The curable resin may have at least one of urethane bonds and urea bonds, or it may not have at least one. Examples of such resins include urethane resins having urethane bonds and urea resins having urea bonds. It may also be a resin having both urethane bonds and urea bonds.

[0066] The presence of urethane bonds and / or urea bonds can be confirmed using a Fourier transform infrared spectrophotometer (FT-IR).

[0067] The curable resin is preferably composed of a cured product of a first organic material and a second organic material. For example, a cured product obtained by the reaction of a hydroxyl group (OH group) of the first organic material with an isocyanate group (NCO group) of the second organic material is an example.

[0068] When a cured product is obtained by the above reaction, uncured portions of the starting material may remain in the film. For example, the dielectric film may contain at least one of isocyanate groups and hydroxyl groups. In this case, the dielectric film may contain either one of isocyanate groups and hydroxyl groups, or it may contain both isocyanate groups and hydroxyl groups.

[0069] The presence of isocyanate groups and / or hydroxyl groups can be confirmed using a Fourier transform infrared spectrophotometer (FT-IR).

[0070] The first organic material is preferably a polyol having multiple hydroxyl groups in its molecule. Examples of polyols include polyether polyols, polyester polyols, and polyvinyl acetals. Two or more organic materials may be used in combination as the first organic material.

[0071] The second organic material is preferably an isocyanate compound, epoxy resin, or melamine resin having multiple functional groups in its molecule. Two or more organic materials may be used in combination as the second organic material. Among the second organic materials, isocyanate compounds are preferred.

[0072] Examples of isocyanate compounds include aromatic polyisocyanates such as diphenylmethane diisocyanate (MDI) and tolylene diisocyanate (TDI), and aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI). Modified forms of these polyisocyanates, such as those having carbodiimide or urethane, may also be used.

[0073] The epoxy resin is not particularly limited as long as it is a resin having an epoxy ring, and examples include bisphenol A type epoxy resin, biphenyl skeleton epoxy resin, cyclopentadiene skeleton epoxy resin, naphthalene skeleton epoxy resin, and so on.

[0074] The melamine resin is not particularly limited as long as it is an organic nitrogen compound having a triazine ring at the center of its structure and three amino groups around it, for example, alkylated melamine resin. Other modified forms of melamine may also be used.

[0075] In the film capacitor of the present invention, the dielectric film constituting the element body of the capacitor element is preferably obtained by forming a resin solution containing a first organic material and a second organic material into a film, and then curing it by heat treatment.

[0076] In the film capacitor of the present invention, the dielectric film constituting the element body of the capacitor element may mainly contain a vapor-deposited polymerized film. The vapor-deposited polymerized film may have at least one of urethane bonds and urea bonds, or it may not.

[0077] Vapor deposition polymerized films refer to films formed by vapor deposition polymerization and are basically included in curable resins.

[0078] In the film capacitor of the present invention, the dielectric film constituting the element body of the capacitor element may contain a thermoplastic resin as its main component. Examples of thermoplastic resins include polypropylene, polyethersulfone, polyetherimide, and polyarylate.

[0079] In the film capacitor of the present invention, the dielectric film constituting the element body of the capacitor element may also contain additives to add other functions. For example, smoothness can be provided by adding a leveling agent. It is more preferable that the additive is a material having a functional group that reacts with hydroxyl groups and / or isocyanate groups and forms part of the crosslinked structure of the cured product. Examples of such materials include resins having at least one functional group selected from the group consisting of epoxy groups, silanol groups and carboxyl groups.

[0080] In the film capacitor of the present invention, the thickness of the dielectric film constituting the element body of the capacitor element is not particularly limited, but it is preferable to design it appropriately according to the required capacitance and required element volume of the capacitor to be manufactured.

[0081] The thickness of the dielectric film can be measured using an optical film thickness gauge.

[0082] In the film capacitor of the present invention, the type of metal included in the metal layer constituting the element body of the capacitor element is not particularly limited, but it is preferable that the metal layer includes at least one selected from the group consisting of aluminum, titanium, zinc, magnesium, tin, and nickel.

[0083] In the film capacitor of the present invention, the thickness of the metal layer constituting the element body of the capacitor element is not particularly limited, but from the viewpoint of suppressing damage to the metal layer, the thickness of the metal layer is preferably 5 nm or more and 40 nm or less.

[0084] The thickness of the metal layer can be determined by observing a cross-section of the metallized film, obtained by cutting it in the thickness direction, using an electron microscope such as a field emission scanning electron microscope (FE-SEM).

[0085] The film capacitor 1 described above can be manufactured, for example, by the following method. First, prepare a capacitor element 10, a first lead terminal 61 with a first resin member 71 provided at a predetermined position, and a second lead terminal 62 with a second resin member 72 provided at a predetermined position. Weld the first lead terminal 61 to the end face 31e of the first external electrode 31 of the capacitor element 10, and weld the first end 62a of the second lead terminal 62 to the end face 32e of the second external electrode 32. Weld the second end 62b of the second lead terminal 62 to the planar portion 23s of the side surface 23 of the element body 20. １ The second lead-out terminal 62 is routed along the first external electrode 31 side so that its second end 62b is located near the first external electrode 31.

[0086] A pair of laminate materials 41 constituting the laminate film 40 are prepared, and the capacitor element 10 is sandwiched between the pair of laminate materials 41 from above and below. At this time, the first lead terminal 61 and the second lead terminal 62 are made to protrude from the first outlet 51 and the second outlet 52 provided on the flange portion 42. The flange portion 42 of the laminate material 41 is heat-sealed by heat pressing, and the laminate material 41 is integrated. At this time, the flange portion 42 is also heat-sealed to the first resin member 71 and the second resin member 72 which are located at the base of the position where the first lead terminal 61 and the second lead terminal 62 protrude from the outer casing 40. It is preferable to perform the heat sealing process under vacuum in order to remove any internal air or moisture. By performing heat welding in a vacuum, swelling of the laminate material 41 caused by the expansion of internal air when the film capacitor 1 is exposed to high temperatures, and oxidation of the deposited metal due to the influence of internal air and moisture can be effectively suppressed. Although the laminate film 40 deforms slightly to conform to the internal components during heat welding in a vacuum, this does not affect the characteristics of the film capacitor 1. The above-described film capacitor 1 can be manufactured by this method.

[0087] This specification contains the following information:

[0088] The present disclosure (1) comprises a capacitor element having an element body having a first end face and a second end face located at both ends in the longitudinal direction, and a side surface connecting the first end face and the second end face, a first external electrode provided on the first end face of the element body, and a second external electrode provided on the second end face of the element body, a first resin member arranged to surround a part of its outer circumference and connected to the first external electrode, a second resin member arranged to surround a part of its outer circumference and connected to the second external electrode, and a second lead terminal routed along the side surface of the element body toward the first external electrode, and a laminate film including a resin layer. A film capacitor is provided, comprising: a casing body having a welded portion where a resin layer is arranged around the capacitor element to seal the capacitor element, and a first portion and a second portion, which are opposing portions of the resin layer, are welded together, wherein the welded portion includes a first outlet, which is the location where the first portion and the second portion are welded together via the first resin member, and a second outlet, which is the location where the first portion and the second portion are welded together via the second resin member, the first external electrode and the second lead terminal are insulated by the second resin member, and the tips of the first lead terminal and the second lead terminal protrude from the same side of the casing body.

[0089] Disclosure (2) is the film capacitor according to Disclosure (1), wherein the laminate film is a multilayer film having a metal film.

[0090] Disclosure (3) is the film capacitor according to Disclosure (2), wherein the protrusion length of the second resin member from the second outlet is 5.15 mm or more.

[0091] Disclosure (4) is a film capacitor according to any one of Disclosures (1) to (3), wherein the distance between the first lead terminal and the second lead terminal is 50 mm or less.

[0092] Disclosure (5) is a film capacitor according to any one of Disclosures (1) to (4), wherein the thickness of the second resin member is 0.02 mm or more and 0.3 mm or less.

[0093] In the present disclosure (6), the second resin member is disposed between the second lead-out terminal and the side surface along the direction from the first external electrode toward the second external electrode starting from the first external electrode on the side surface of the element body, and the length of the second resin member along the direction from the first external electrode toward the second external electrode on the side surface is not less than the minimum space distance defined in JIS C 60664-1. The film capacitor according to any one of the present disclosures (1) to (5).

[0094] 1 Film capacitor 10 Capacitor element 20 Element body 21 First end face of the element body 22 Second end face of the element body 23 Side surface of the element body 23s １ Plane portion 23s of the side surface of the element body ２ Curved surface portion of the side surface of the element body 31 First external electrode 31e End face of the first external electrode 31s Side surface of the first external electrode 32 Second external electrode 32e End face of the second external electrode 32s Side surface of the second external electrode 40 Laminate film (outer package) 41 Laminate material 42 Flange portion (first portion, second portion, welding portion) 51 First lead-out port 52 Second lead-out port 61 First lead-out terminal 62 Second lead-out terminal 62a First end portion of the second lead-out terminal 62b Second end portion of the second lead-out terminal 71 First resin member 72 Second resin member 81 First metallized film 82 Second metallized film 83 First dielectric film 84 Second dielectric film 85 First metal layer 86 Second metal layer

Claims

1. A capacitor element comprising: an element body having first and second end faces located at both ends in the longitudinal direction, and a side surface connecting the first and second end faces; a first external electrode provided on the first end face of the element body; and a second external electrode provided on the second end face of the element body; a first lead terminal comprising a first resin member arranged to surround a part of its outer circumference and connected to the first external electrode; a second lead terminal comprising a second resin member arranged to surround a part of its outer circumference and connected to the second external electrode, and routed along the side surface of the element body toward the first external electrode; and an outer casing made of a laminate film including a resin layer, which seals the capacitor element so that the resin layer is arranged around the capacitor element, and which has a welded portion in which a first portion and a second portion, which are opposite portions of the resin layer, are welded together. The welded portion includes a first outlet, which is a location where the first portion and the second portion are welded together via the first resin member, and a second outlet, which is a location where the first portion and the second portion are welded together via the second resin member, the first external electrode and the second lead terminal are insulated by the second resin member, and the tip of the first lead terminal and the tip of the second lead terminal protrude from the same side of the outer casing, a film capacitor.

2. The film capacitor according to claim 1, wherein the laminate film is a multilayer film having a metal film.

3. The film capacitor according to claim 2, wherein the protrusion length of the second resin member from the second outlet is 5.15 mm or more.

4. The film capacitor according to any one of claims 1 to 3, wherein the distance between the first lead terminal and the second lead terminal is 50 mm or less.

5. The film capacitor according to any one of claims 1 to 4, wherein the thickness of the second resin member is 0.02 mm or more and 0.3 mm or less.

6. The film capacitor according to any one of claims 1 to 5, wherein the second resin member is arranged on the side surface of the element body between the second lead terminal and the side surface in a direction from the first external electrode toward the second external electrode, with the first external electrode as the starting point, and the length of the second resin member in the direction from the first external electrode toward the second external electrode on the side surface is equal to or greater than the minimum spatial distance specified in JIS C 60664-1.

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