Capacitor

Abstract

A capacitor includes: a capacitor element including a first electrode disposed on one end surface of the capacitor element, a second electrode disposed on another end surface of the capacitor element, and a peripheral surface connecting the first electrode to the second electrode; a first bus bar and a second bus bar connected to the first electrode and the second electrode, respectively; a case accommodating the capacitor element; and a filling resin in which the capacitor element, a part of the first bus bar, and a part of the second bus bar are embedded, the filling resin being filled within the case. The peripheral surface includes a flat surface. The first bus bar includes an opposing portion having a flat plate shape and facing the flat surface.The opposite section includes a projection that projects toward the flat surface and rests against the flat surface.

Description

Background1. Technical FieldThe present disclosure relates to a capacitor.2. DESCRIPTION OF THE RELATED ARTFor example, PTL 1 describes a capacitor in which a capacitor element unit formed by connecting a bus bar to electrodes of a capacitor element is accommodated in a housing, and the housing is filled with a filling resin, the capacitor being configured such that the bus bar has a portion facing a circumferential surface of the capacitor element.In the foil capacitor of PTL 1, a lower bus bar includes a relay portion as a portion facing the circumferential surface of the capacitor element. The relay portion extends upward along the circumferential surface of the capacitor element from an end of a lower electrode terminal portion connected to a lower end surface electrode of the capacitor element. A gap is formed between the circumferential surface of the capacitor element and the relay portion, and the filler resin enters the gap. The filler resin is injected into the housing in a liquid phase state and then cured inside the housing. This results in the peripheral surface of the capacitor element and the relay portion being connected to each other by the filler resin.List of Citer ListsPatent LiteraturePTL 1: Japanese Unexamined Patent Publication No. 2018 / 2018 / 2018 / 2018 / 2018 / 20051656SummaryTechnical ProblemIn the foil capacitor according to PTL 1, it is difficult to maintain a constant width of the gap between the circumferential surface of the capacitor element and the relay portion. Therefore, when the width of the gap becomes small, the thickness of the filler resin that has penetrated into the gap decreases, and thus peeling is more likely to occur between the circumferential surface and the filler resin or between the relay portion and the filler resin. When the width of the gap becomes small, the liquid phase filler resin does not sufficiently enter the gap, making voids (voids) easier to occur in the cured filler resin that has entered the gap. As a result, there is a risk that moisture will more likely enter the peeled portions and voids, which reduces the moisture resistance of the film capacitor.Therefore, an object of the present disclosure is to provide a capacitor that can maintain a constant width of the gap between the circumferential surface of the capacitor element and an opposing portion of the bus bar facing the circumferential surface.Solution of the ProblemA first aspect of the present disclosure relates to a capacitor. The capacitor according to the aspect includes: a capacitor element including a first electrode disposed on one end surface of the capacitor element, a second electrode disposed on another end surface of the capacitor element, and a circumferential surface connecting the first electrode to the second electrode; a first bus bar and a second bus bar respectively connected to the first electrode and the second electrode; a housing accommodating the capacitor element; and a filler resin in which the capacitor element, a part of the first bus bar, and a part of the second bus bar are embedded, the filler resin being filled inside the housing. Here, the circumferential surface includes a flat surface. The first bus bar includes an opposing portion having a flat plate shape and facing the flat surface. The opposing portion includes a protrusion that protrudes toward the planar surface and abuts the planar surface.Advantageous Effect of the InventionAccording to the present disclosure, it is possible to provide a capacitor that can maintain a constant width of the gap between the circumferential surface of the capacitor element and the opposing portion of the bus bar facing the circumferential surface.The effects or meanings of the present disclosure will be further clarified by the following description of exemplary embodiments. The exemplary embodiments described below are merely examples of implementation of the present disclosure, and the present disclosure is in no way limited to the description in the following exemplary embodiments.Brief Description of the DrawingsFIG. 1 is a perspective view illustrating a film capacitor according to a first exemplary embodiment; FIG. 2 is a cross-sectional view illustrating the film capacitor according to the first exemplary embodiment cut parallel to an XZ plane at a center in a Y-axis direction; FIG. 3 is a perspective view illustrating a capacitor element module according to the first exemplary embodiment; FIG. 4 is a perspective view illustrating the capacitor element module according to the first exemplary embodiment; FIG. 5 is a cross-sectional view illustrating the capacitor element module according to the first exemplary embodiment, which is cut parallel to an XY plane at a position on a negative Z-axis side relative to an isolation element; FIG. 6 is an exploded perspective view illustrating a first bus bar according to the first exemplary embodiment; FIG. 7 is an exploded perspective view illustrating a second bus bar according to the first exemplary embodiment; FIG. 8A is a cross-sectional view illustrating a main part of the first bus bar according to the first exemplary embodiment, which is cut at a position of a first connection and shows a portion near a first connection terminal portion; FIG. 8B is a cross-sectional view illustrating a main part of the second bus bar according to the first exemplary embodiment, which is cut at a position of a second connection and shows a portion near a second connection terminal portion; FIGS. 9A and 9B are perspective views illustrating the insulating member according to the first exemplary embodiment; FIG. 10 is a perspective view illustrating a housing according to the first exemplary embodiment; FIG. 11 is a plan view illustrating the film capacitor according to the first exemplary embodiment, in which the external terminals are connected to the first connection terminal portion and the second connection terminal portion; FIG. 12 is a perspective view illustrating a film capacitor according to a second exemplary embodiment; FIG. 13 is a perspective view illustrating the film capacitor according to the second exemplary embodiment; and FIG. 14 is a plan view illustrating a capacitor element module according to the second exemplary embodiment.Detailed Descriptions of EmbodimentsHereinafter, a foil capacitor according to an exemplary embodiment of a capacitor of the present disclosure will be described with reference to the drawings. For convenience, an X-axis, a Y-axis, and a Z-axis that are perpendicular to each other are added to the drawings.First Exemplary EmbodimentFilm capacitor 1 according to a first exemplary embodiment will be described. The film capacitor 1 is a so-called case shaping type capacitor.FIG. 1 is a perspective view of the film capacitor 1. FIG. 2 is a cross-sectional view of the film capacitor 1 cut parallel to an XZ plane at a center in the Y-axis direction. Note that in FIG. 2, for convenience, the filling resin 30 is shown in a transparent state.The film capacitor 1 includes a capacitor element module 10, a case 20, and a filler resin 30. the capacitor element module 10 is accommodated in the case 20, and the case 20 is filled with filler resin 30.The filling resin 30 is a thermosetting resin such as an epoxy resin. The filler resin 30 serves as an outer body covering the capacitor element module 10 inside the housing 20. A portion of the capacitor element module 10 embedded in the filler resin 30 is protected from moisture and shock by the case 20 and the filler resin 30.FIGS. 3 and 4 are perspective views of the capacitor element module 10. FIG. 5 is a cross-sectional view of the capacitor element module 10 cut parallel to an XY plane at a position on a negative Z-axis side relative to the isolation member 400. FIG. 6 is a perspective view of a first bus bar 200. FIG. 7 is a perspective view of the second bus bar 300. FIG. 8A is a cross-sectional view of a main part of the first bus bar 200 cut at a position of the first connection 231 and showing a portion near the first connection terminal portion 230. FIG. 8B is a cross-sectional view of a main part of the second bus bar 300 cut at a position of the second connection 331 and showing a portion near the second connection terminal portion 330. FIGS. 9A and 9B are perspective views of the isolation member 400.The capacitor element module 10 includes four capacitor elements 100, a first bus bar 200, a second bus bar 300, and the insulating member 400.The capacitor element 100 is formed by stacking two metallized films each having aluminum vapor deposited on a dielectric film, and winding or laminating the stacked metallized films and pressing the stacked metallized films, thereby forming the stacked metallized films into a shape similar to a flattened elongated cylinder. In the capacitor element 100, the first electrode 110 is formed on one end surface by spraying metal such as zinc, and the second electrode 120 is formed on another end surface by spraying metal such as zinc in a similar manner.The capacitor element 100 has a circumferential surface 130 connecting the first electrode 110 and the second electrode 120. The peripheral surface 130 includes: two first planar surfaces 131 arranged in an X-axis direction that is a lateral direction of the capacitor element 100; two second planar surfaces 132 arranged in the Y-axis direction that is a longitudinal direction of the capacitor element 100; and four arc surfaces 133 located between the first planar surfaces 131 and the second planar surfaces 132. A dimension of the first planar surfaces 131 in the Y-axis direction is larger than a dimension of the second planar surfaces 132 in the X-axis direction.Note that the capacitor element 100 according to the present exemplary embodiment is formed of metallized films each of which has aluminum vapor-deposited on a dielectric film. Moreover, the capacitor element 100 may be formed of metallized films that have evaporated another metal such as zinc or magnesium. Alternatively, the capacitor element 100 may be formed with metallized films made by evaporating a plurality of metals of these metals or metallized films made by evaporating an alloy of these metals.Four capacitor elements 100 are arranged in two rows in both the X-axis direction and the Y-axis direction so that their circumferential surfaces 130 face each other. In each capacitor element 100, the first electrode 110 is oriented in the Z-axis negative direction and the second electrode 120 is oriented in the Z-axis positive direction.The first bus bar 200 is formed by cutting out a suitable shape from a conductive material such as a copper plate, and then bending. The first bus bar 200 is therefore a single structure including a first electrode terminal portion 210, a first relay portion 220, and a first connection terminal portion 230.The first electrode terminal portion 210 has a substantially rectangular flat plate shape elongated in the Y-axis direction. The two corners of the first electrode terminal portion 210 in the X-axis positive direction are formed in large arcs. At the end of the first electrode terminal portion 210 in the positive X-axis direction, a substantially U-shaped notch 211 is formed in a central portion.The first relay portion 220 provides a relay between the first electrode terminal portion 210 and the first connection terminal portion 230. The first relay portion 220 has a substantially rectangular flat plate shape that is elongated in the Y-axis direction and extends perpendicularly to the first electrode terminal portion 210 in the positive Z-axis direction from the end of the first electrode terminal portion 210 in the negative X-axis direction. The dimension of the first relay portion 220 in the Z-axis direction is larger than the dimension of the capacitor element 100 in the Z-axis direction, that is, the direction in which the first electrode 110 and the second electrode 120 are arranged.The first relay portion 220 is provided with two protrusions 221 at two positions on the surface of the positive X-axis side, one on the positive Y-axis side and the other on the negative Y-axis side, each position being closer to the first electrode terminal portion 210 than the center of the Z-axis direction, in a manner that two protrusions 221 are arranged in the Y-axis direction. Four protrusions 221 have a flat, substantially cylindrical shape and project in the positive X-axis direction from the surface of the first relay portion 220 on the positive X-axis side. The distal end surface 221 aof each protrusion 221 has a flat shape, and the outer peripheral edge of the distal end surface 221 ais chamfered into an arc shape. Moreover, at the Y-axis positive side end and the Y-axis negative side end of the first relay portion 220 in the vicinity of the first connection terminal portion 230, first protrusion pieces 222 are formed protruding in the Y-axis positive direction and the Y-axis negative direction, respectively.The first connection terminal portion 230 has a substantially rectangular flat plate shape that is elongated in the Y-axis direction and extends in the X-axis negative direction perpendicular to the first relay portion 220 from the end of the first relay portion 220 in the Z-axis positive direction. On an inner portion of the surface of the first connection terminal portion 230, at two positions arranged in the Y-axis direction, first connections 231 to which welding is performed when an external terminal is connected are provided. On the surface of the first connection terminal portion 230, as a designation portion indicating the area of each first connection 231, a substantially rectangular annular first groove 232 indicating a boundary between the area of each first connection 231 and other areas is provided.As shown in FIG. 8A, the first groove 232 has a V-shaped cross section, for example. The first groove 232 may have a cross-sectional shape other than V-shaped, such as semicircular, U-shaped, or rectangular. The first connection terminal portion 230 has the thickness D 1 at a portion of each first groove 232, and the thickness D 1 is smaller than the thickness D 2 at a portion of each first connection 231.The second bus bar 300 is formed by cutting out a suitable shape from a conductive material such as a copper plate, and then bending. The second bus bar 300 is therefore a single structure including a second electrode terminal portion 310, a second relay portion 320, and a second connection terminal portion 330.The second electrode terminal portion 310 has a substantially rectangular flat plate shape elongated in the Y-axis direction, and the X-axis negative side end 310 a(the second relay portion 320) is increased by one step in the Z-axis direction. The two corners of the second electrode terminal portion 310 in the X-axis positive direction are formed into large arcs. At the end of the second electrode terminal portion 310 in the X-axis positive direction, a substantially semicircular notch 311 is formed at a central portion.The second relay portion 320 provides a relay between the second electrode terminal portion 310 and the second connection terminal portion 330. The second relay portion 320 has a substantially rectangular flat plate shape that is elongated in the Y-axis direction and extends perpendicularly to the second electrode terminal portion 310 in the positive Z-axis direction from the end of the second electrode terminal portion 310 in the negative X-axis direction. At the positive Y-axis side end and the negative Y-axis side end of the second relay portion 320, second protrusions 321 are formed protruding in the positive Y-axis direction and the negative Y-axis direction, respectively.The second connection terminal portion 330 has a substantially rectangular flat plate shape that is elongated in the Y-axis direction and extends in the X-axis positive direction perpendicular to the second relay portion 320 from the end of the second relay portion 320 in the Z-axis positive direction. On an inner portion of the surface of the second connection terminal portion 330, at two positions arranged in the Y-axis direction, there are provided second connections 331 to which welding is performed when an external terminal is connected. On the surface of the second connection terminal portion 330, as a designation portion indicating the area of each second connection 331, a substantially rectangular annular second groove 332 indicating a boundary between the area of each second connection 331 and other areas is provided.As shown in FIG. 8B, the second groove 332 has a V-shaped cross section, for example. The second groove 332 may also have a cross-sectional shape other than V-shaped, such as semicircular, U-shaped, or rectangular. The second connection terminal portion 330 has a thickness D 3 at a portion of each second connection 332 that is smaller than the thickness D 4 at a portion of each second connection 331.The insulating member 400 is formed of an electric insulation material such as polyphenylene sulfide (PPS), and has a substantially rectangular flat plate shape elongated in the Y-axis direction. On the first surface 400 aon the negative X-axis side and the second surface 400 bon the positive X-axis side of the insulating member 400, a substantially rectangular first recess 410 and a second recess 420 are formed, respectively, which are elongated in the Y-axis direction and are recessed relative to these surfaces. In the first depression 410 at the positive Y-axis side end, a passage 411 is provided which extends toward the negative Z-axis side end of the insulating member 400.The insulating member 400 is provided with holding portions 430 at both ends in the Y-axis direction. Each holding portion 430 has a first fitting groove 431 opening in the Z-axis negative direction and the Y-axis direction on the first surface 400 aside, and a second fitting groove 432 opening in the Z-axis positive direction and the Y-axis direction on the second surface 400 bside. Moreover, at the positive Z-axis end of the insulating member 400, a land portion 440 extending in the negative X-axis direction is provided.In the capacitor element module 10, the first electrode terminal portion 210 of the first bus bar 200 contacts the first electrodes 110 of the four capacitor elements 100 from the Z-axis negative side. The first electrode terminal portion 210 and the four first electrodes 110 are joined by joining methods such as welding and soldering. Thus, the first bus bar 200 is electrically connected to four first electrodes 110.The second electrode terminal portion 310 of the second bus bar 300 contacts the second electrodes 120 of the four capacitor elements 100 from the positive Z-axis side. There is a gap between the end 310 aof the second electrode terminal portion 310 and the second electrode 120. The second electrode terminal portion 310 and the four second electrodes 120 are joined together by joining methods such as welding and soldering. Thus, the second bus bar 300 is electrically connected to four second electrodes 120.The first relay portion 220 of the first bus bar 200, which serves as an opposing portion included in the first bus bar 200, faces the first planar surface 131 of the circumferential surface 130 of each of the two capacitor elements 100 on the X-axis negative side from the X-axis negative side over the entire area between the first electrode 110 and the second electrode 120. The distal end surface 221 aof each of the two positive Y-axis-side protrusions 221 of the first relay portion 220 abuts on the first planar surface 131 of the positive Y-axis-side capacitor element 100 at a position closer to the first electrode 110 than the second electrode 120. Similarly, the distal end surface 221 aof each of the two negative Y-axis-side protrusions 221 of the first relay portion 220 abuts on the first planar surface 131 of the negative Y-axis-side capacitor element 100 at a position closer to the first electrode 110 than the second electrode 120.The positive Z-axis side portion of the insulation member 400 is disposed between and in contact with the first relay portion 220 of the first bus bar 200 and the second relay portion 320 of the second bus bar 300. In addition, the negative Z-axis side portion of the insulating member 400 is disposed between and in contact with the first relay portion 220 of the first bus bar 200 and the first planar surface 131 of each of the two negative X-axis side capacitor elements 100. In this way, insulation between the first relay portion 220 and both the second relay portion 320 and the second electrode 120 is ensured.The thickness D 5 of the insulation member 400 is made equal to the protrusion length D 6 of each of the four protrusions 221 of the first relay portion 220 (see FIG. 2 ). Thus, the first planar surface 131 of each of the two capacitor elements 100 is parallel to the first relay portion 220. Between the first planar surface 131 of each of the two capacitor elements 100 and the first relay part 220, a uniform gap S having a constant width (width for the thickness D 5 and the protrusion length D 6) is secured. By maintaining a constant distance between two capacitor elements 100 and the first relay section 220, i.e. by reducing variations in this distance, the electrical characteristics of the foil capacitor 1 will less likely vary.The first protrusion piece 222 of the first relay portion 220 is fitted into the first fitting groove 431 of the holding portion 430 of the insulating member 400 from the negative Z-axis side, and the first connection terminal portion 230 abuts on the land portion 440 of the insulating member 400 from the negative Z-axis side. The second protrusion piece 321 of the second relay portion 320 is fitted into the second fitting groove 432 of the holding portion 430 of the insulating member 400 from the negative Z axis side, and the second connection terminal portion 330 abuts the holding portion 430 from the positive Z axis side. Thus, the first bus bar 200, the second bus bar 300, and the insulating member 400 are less likely to separate in the X-axis direction, the Y-axis direction, and the Z-axis direction.FIG. 10 is a perspective view of the housing 20.The housing 20 is made of a resin material, for example, a thermoplastic resin such as polyphenylene sulfide (PPS). The housing 20 may also be made of a thermosetting resin such as epoxy resin.The housing 20 has a substantially rectangular box shape and includes a substantially rectangular opening 21, a substantially rectangular bottom portion 22 facing the opening 21, a substantially rectangular first side wall 23 and a second side wall 24 extending from both ends of the bottom portion 22 toward the opening 21 (in the positive Z-axis direction) on the X-axis direction side and facing each other, and a rectangular third side wall 25 and a fourth side wall 26 extending from both ends of the bottom portion 22 on the Y-axis direction side toward the opening 21 (in the positive Z-axis direction) and facing each other.On the first side wall 23, the third side wall 25 and the fourth side wall 26, a mounting tab 27 is provided in each case. Each mounting tab 27 has an insertion hole 27a. The metal collar 27 bis fitted into the insertion hole 27 ato increase the strength of the hole. In addition, a positioning tab 28 is provided on each of the third side wall 25 and the fourth side wall 26. Each positioning tab 28 has a positioning pin 28a projecting toward the bottom portion 22. When the film capacitor 1 is installed to an installation portion of an external device, the mounting tab 27 is fixed to the installation portion by screws or the like. At this time, the positioning pin 28a is inserted into a positioning hole provided in the installation portion to position the film capacitor 1 relative to the installation portion.Inside the housing 20, the capacitor element module 10 is arranged in a manner that the first electrodes 110 of the four capacitor elements 100 face the bottom portion 22 of the housing 20. The first relay portion 220 of the first bus bar 200 extends along the second side wall 24 of the housing 20 from the bottom portion 22 side toward the opening 21, is led out from the molding surface 31 of the filler resin 30 to the outside of the filler resin 30, and the first connection terminal portion 230 of the first bus bar 200 is exposed from the filler resin 30. Similarly, the second relay portion 320 of the second bus bar 300 is led out from the molding surface 31 to the outside of the filler resin 30, and the second connection terminal portion 330 of the second bus bar 300 is exposed from the filler resin 30.During assembly of the foil capacitor 1, a receiving step is first performed to receive the capacitor element module 10 through the opening 21 inside the housing 20. The capacitor element module 10 is positioned at a predetermined position inside the housing 20 by a positioning device.Next, a resin injection step is performed to inject liquid phase filling resin 30 into the housing 20 through the opening 21, filling the housing 20 to a position near the opening 21. The first connection terminal portion 230 of the first bus bar 200 and the second terminal connection portion 330 of the second bus bar 300 are exposed from a liquid surface of the liquid phase fill resin 30 which becomes the molding surface 31 after curing.Between the first planar surface 131 of each of the two capacitor elements 100 and the first relay portion 220 of the first bus bar 200 on the X-axis negative side, the gap S of a constant width is secured by the insulating member 400 and four protrusions 221. Therefore, the injected filling resin 30 easily enters the gap S, which completely fills the gap S and makes air less likely to remain in the gap S. Specifically, the filler resin 30 enters the gap S not only from both sides in the Y-axis direction of the first relay portion 220, but also, as indicated by the broken arrows in FIG. 2, through the gap between the end 310 aof the second electrode terminal portion 310 of the second bus bar 300 and the second electrode 120 of each of the two capacitor elements 100 on the X-axis negative side and through the gap between the two second electrodes 120, thereby making the filler resin 30 more likely to reach the gap S.Moreover, the injected filling resin 30 penetrates the first recess 410 and the second recess 420 of the insulating member 400, and the first recess 410 and the second recess 420 are filled with the filling resin 30.Moreover, in the capacitor element module 10, the notch 211 of the first electrode terminal portion 210 of the first bus bar 200 and the notch 311 of the second electrode terminal portion 310 of the second bus bar 300 are provided so as to align with a space formed at a central portion of the four capacitor elements 100 (see FIGS. 3 and 4 ). Therefore, injected filler resin 30 is more likely to pass between the capacitor element module 10 and the bottom portion 22 of the housing 20 through the two notches 211, 311 and the space at the central portion.Once the housing 20 is filled with the filling resin 30, a resin curing step is performed to heat the inside of the housing 20, thereby heating the filling resin 30. In this way, the filling resin 30 is cured in the housing 20. The filler resin 30 serves as the outer body covering the capacitor element module 10.As shown in FIG. 1, the film capacitor 1 is thus completed.The circumferential surface 130 of each of the two capacitor elements 100 on the negative X-axis side and the first relay portion 220 are connected to the filler resin 30 located in the gap S therebetween. At this time, a constant thickness is secured for the filler resin 30 in the gap S, and thus peeling is less likely to occur between the circumferential surface 130 of each capacitor element 100 and the filler resin 30, or between the first relay portion 220 and the filler resin 30. Also, since the gap S is less likely to become narrower, voids (voids) present in the gap S are less likely to occur in the filling resin 30. Therefore, moisture resistance deterioration due to moisture entering peeled portions or voids is less likely to occur, and therefore the moisture resistance of the sheet capacitor 1 can be improved. Moreover, the first relay portion 220 and the insulating member 400 are connected to the filling resin 30 in the first recess 410, and the second relay portion 320 and the insulating member 400 are connected to the filling resin 30 in the second recess 420. As a result, moisture is less likely to enter between the first relay portion 220 and the insulating member 400, and between the second relay portion 320 and the insulating member 400, thereby further improving the moisture resistance of the foil capacitor 1.During the resin injection step, when the liquid phase filler resin 30 is injected into the housing 20, numerous air bubbles may be generated in the liquid phase filler resin 30 inside the housing 20 due to the air entrainment. There is a risk that these air bubbles burst near a liquid surface, causing the resin to scatter from the liquid surface, and the scattered resin may adhere to the first joint 231 of the first connection terminal portion 230 and the second joint 331 of the second connection terminal portion 330 located near the liquid surface. In addition, there is a risk that foreign substances such as dust may adhere to the first joint 231 and the second joint 331 during the various steps until completion of the film capacitor 1.When external terminals are connected to the first connection terminal portion 230 and the second connection terminal portion 330, welding is performed within the regions of the first joint 231 and the second joint 331. Therefore, in the finished film capacitor 1, when foreign substances such as resin and dust adhere to the first joint 231 or the second joint 331, there is a risk that the foreign substances may interfere with welding.Accordingly, in the finished film capacitor 1, inspection is performed to check whether foreign matter adheres to the first connection 231 or the second connection 331. In the foil capacitor 1 of the present exemplary embodiment, on the surface of the first connection terminal portion 230, the boundary between the area of the first recess 231 and other areas is indicated by the first groove 232 serving as the designation portion. Similarly, on the surface of the second connection terminal portion 330, the boundary between the area of the second connection 331 and other areas is indicated by the second groove 332 serving as the designation portion. Therefore, an inspector can easily grasp the first link 231 and the second link 331 and can easily make inspection for the presence or absence of foreign matter adhesion. In this way, the inspector can easily detect adhesion of foreign matter, particularly resin, to the first joint 231 and the second joint 331.The film capacitor 1 is mounted on the external device. The external device is provided with an external terminal T 1 corresponding to the first connection terminal portion 230 of the first bus bar 200 and an external terminal T 2 corresponding to the second connection terminal portion 330 of the second bus bar 300. The external terminal T 1 is connected to the first connection terminal portion 230 by welding, and the external terminal T 2 is connected to the second connection terminal portion 330 by welding.FIG. 11 is a plan view of the film capacitor 1 in a state where the external terminals T 1, T 2 are connected to the first connection terminal portion 230 and the second connection terminal portion 330.The external terminal T 1 overlaps the surface of the first connection terminal portion 230 in a manner to cover two first connections 231. A connection surface of the external terminal T 1 contacting the first connection terminal portion 230 is flat. Similarly, the external terminal T 2 overlaps the surface of the second connection terminal portion 330 in a manner to cover two second connections 331. A connection surface of the external terminal T 2 contacting the second connection terminal portion 330 is flat.Welding using welding equipment (laser welding, resistance welding, etc.) is performed within the regions of each first joint 231 and each second joint 331. Thus, the external terminal T 1 is connected to the first connection terminal portion 230, and the external terminal T 2 is connected to the second connection terminal portion 330.The actual welded portion P has an elongated shape in the longitudinal direction (Y-axis direction) of the first connection terminal portion 230 and the second connection terminal portion 330. Therefore, in order to correspond to the shape of the welded portion P, each first joint 231 and each second joint 331 have a substantially rectangular shape. In addition, there is a risk that the position of the welded portion P may be slightly deviated due to assembly tolerances and component tolerances, etc., of the film capacitor 1. Therefore, in consideration of an amount of positional deviation of the welded portion P, the sizes of each first joint 231 and each second joint 331 are made larger than the size of the welded portion P. Note that when the shape of the welded portion P is changed, the shapes of each first joint 231 and each second joint 331 may also be changed accordingly.The designation portion indicating each first connection 231 is the first groove 232 that does not protrude from the surface of the first connection terminal portion 230. Therefore, the contact of the connection surface of the external terminal T 1 with the surface of the first connection terminal portion 230 is not hindered by the designation portion. Moreover, the first connection terminal portion 230 has a thickness D 1 at a portion of each first groove 232, the thickness D 1 being smaller than the thickness D 2 at a portion of each first connection 231 (see FIG. 8A ). Therefore, since the heat is less likely to propagate in the portion of each first groove 232, the heat generated at each first joint 231 during welding is less likely to escape from each first joint 231. Thus, the welding at each first joint 231 can be performed more efficiently.Similarly, the designation portion indicating each second connection 331 is the second groove 332 that does not protrude from the surface of the second connection terminal portion 330. Therefore, the contact of the connection surface of the external terminal T 2 with the surface of the second connection terminal portion 330 is not hindered by the designation portion. Moreover, the second connection terminal portion 330 has a thickness D 3 at a portion of each second groove 332, the thickness D 3 being smaller than the thickness D 4 at a portion of each second connection 331 (see FIG. 8B ). Therefore, since the heat is less likely to propagate in the portion of each second groove 332, the heat generated at each second joint 331 during welding is less likely to escape from each second joint 331. Thus, the welding at each second joint 331 can be performed more efficiently.Note that since the first joint 231 and the second joint 331 are respectively characterized by the first groove 232 and the second groove 332, it is also possible that the welding device identifies and correspondingly welds the areas of the first joint 231 and the second joint 331 also by image recognition.< Of First Exemplary Embodiment>The first exemplary embodiment described above achieves the following effects.The foil capacitor 1 includes: a capacitor element 100 including a first electrode 110 formed on one end surface, a second electrode 120 formed on another end surface, and a circumferential surface 130 connecting the first electrode 110 and the second electrode 120; a first bus bar 200 and a second bus bar 300 connected to the first electrode 110 and the second electrode 120, respectively; a housing 20 accommodating the capacitor element 100; and a filler resin 30 filled in the housing 20 and used to embed the capacitor element 100 and a part of the first bus bar 200 and the second bus bar 300. The peripheral surface 130 includes a first planar surface 131 (planar surface), and the first bus bar 200 includes a flat plate-shaped first relay portion 220 (opposing portion) facing the planar surface. The first relay portion 220 includes protrusions 221 that protrude toward the first planar surface 131 and abut on the first planar surface 131.According to this configuration, it is possible to maintain a constant width of the gap S between the first planar surface 131 of the circumferential surface 130 of the capacitor element 100 and the first relay portion 220 of the first bus bar 200 by the interposition of protrusions 221 in the gap S. Therefore, a constant thickness is secured for the filler resin 30 existing in the gap S, and thus peeling is less likely to occur between the circumferential surface 130 and the filler resin 30 or between the first relay portion 220 and the filler resin 30. In addition, since the gap S is less likely to become narrow, the liquid phase filler resin 30 is more likely to flow into the gap S, and voids are less likely to be formed in the filler resin 30 existing in the gap S. Therefore, moisture resistance deterioration due to moisture entering peeled portions or voids is less likely to occur, and therefore the moisture resistance of the sheet capacitor 1 can be improved (Effect 1).In addition, since variations in the distance between the circumferential surface 130 of the capacitor element 100 and the first relay portion 220 of the first bus bar 200 are less likely to occur, variations in the electrical characteristics of the foil capacitor 1 are less likely to occur (Effect 2).Moreover, the first relay portion 220 faces the first planar surface 131 across the area between the first electrode 110 and the second electrode 120. The insulating member 400 is interposed between the first planar surface 131 and the first relay portion 220 on the second electrode 120 side.According to this configuration, not only the protrusions 221 but also the insulating member 400 can maintain a constant width of the gap S between the first planar surface 131 and the first relay portion 220 (Effect 3).Furthermore, protrusions 221 are provided on the first relay portion 220 at positions closer to the first electrode 110 than to the second electrode 120.According to this configuration, the protrusions 221 and the insulating member 400 can be arranged in a balanced manner in the direction in which the first electrode 110 and the second electrode 120 are arranged, and thus it becomes easier to maintain a constant width of the gap S over the entire area between the first planar surface 131 and the first relay portion 220 (Effect 4).Moreover, the housing 20 includes an opening 21, a bottom portion 22 facing the opening 21, and a second side wall 24 (side wall) extending from the end of the bottom portion 22 toward the opening 21. The capacitor element 100 is disposed inside the housing 20 in a manner that the first electrode 110 faces the bottom portion 22. The first relay portion 220 extends along the second side wall 24 within the housing 20.In a configuration in which the capacitor element 100 is disposed inside the housing 20 in a manner that the first electrode 110 faces the bottom portion 22 and the first relay portion 220 extends along the second side wall 24 inside the housing 20, the gap S between the first planar surface 131 and the first relay portion 220 is located relatively far from the opening 21 of the housing 20, and therefore, the filler resin 30 is less likely to enter the gap S compared to a configuration in which the gap S is closer to the opening 21.However, according to this configuration, when the gap S between the first planar surface 131 and the first relay portion 220 is located relatively far from the opening 21 of the housing 20, the interposition of the protrusions 221 into the gap S makes it easier for the filler resin 30 to enter the gap S, and thus it is possible to effectively suppress the occurrence of voids within the filler resin 30 existing in the gap S (Effect 5).Moreover, the distal end surface 221 a, which abuts on the first flat surface 131, of the protrusion 221 is flat. According to this configuration, stress applied to the first planar surface 131 due to the abutting contact of the protrusion 221 is alleviated, making the capacitor element 100 less susceptible to damage (Effect 6).In addition, the first relay portion 220 is parallel to the first planar surface 131.According to this configuration, the thickness of the filler resin 30 existing in the gap S can be made uniform between the first planar surface 131 and the first relay portion 220, thereby preventing the filler resin 30 from becoming partially thin.In addition, the thickness D 5 of the insulation member 400 is equal to the protrusion length D 6 of the protrusion 221.According to this configuration, the first relay portion 220 and the first planar surface 131 are less likely to be parallel in the direction in which the first electrode 110 and the second electrode 120 are arranged (Effect 7).Moreover, the first relay portion 220 includes a plurality (two) of protrusions 221 arranged in a direction perpendicular to the direction in which the first electrode 110 and the second electrode 120 are arranged.According to this configuration, the protrusions 221 abut on the first planar surface 131 at a plurality of locations (two locations) in the direction perpendicular to the direction in which the first electrode 110 and the second electrode 120 are arranged, and thus the first relay portion 220 and the first planar surface 131 are more likely to be parallel (Effect 8).Second Exemplary EmbodimentThe film capacitor 2 according to a second exemplary embodiment will be described.FIGS. 12 and 13 are cross-sectional views of the film capacitor 2. in FIG. 12, the film capacitor 2 cut along the line B-B' in FIG. 13 is shown. In Fig. 13, the film capacitor 2 cut along the line A-A' in Fig. 12 is shown. FIG. 14 is a plan view of the capacitor element module 40; note that in FIGS. 12 and 13, for convenience, the filler resin 60 is shown as transparent.The film capacitor 2 includes a capacitor element module 40, a case 50, and a filler resin 60. the capacitor element module 40 is accommodated in the case 50, and the case 50 is filled with filler resin 60.The filler resin 60 is a thermosetting resin such as epoxy resin, and the filler resin 60 is injected into the housing 50 in a liquid phase state and cured by heating to cover the capacitor element module 40 inside the housing 50. A portion of the capacitor element module 40 embedded in the filler resin 60 is protected from moisture and shock by the case 50 and the filler resin 60.The capacitor element module 40 includes the capacitor element 500, the first bus bar 600, the second bus bar 700, and the insulating member 800.The configuration of the capacitor element 500 is the same as that of the capacitor element 100, and includes a first electrode 510, a second electrode 520, and a circumferential surface 530. The circumferential surface 530 includes two first planar surfaces 531, two second planar surfaces 532, and four arc surfaces 533.The first bus bar 600 is formed by cutting out a suitable shape from a conductive material such as a copper plate, and then bending. The first bus bar 600 is therefore a single structure including the first electrode terminal portion 610, the first relay portion 620, and the first connection terminal portion 630.The first electrode terminal portion 610 has a substantially rectangular flat plate shape elongated in the Y-axis direction. The first electrode terminal portion 610 contacts the first electrode 510 of the capacitor element 500 from the X-axis positive side. The first electrode terminal portion 610 and the first electrode 510 are joined together by joining methods such as welding and soldering. Thus, the first bus bar 600 is electrically connected to the first electrode 510.The first relay portion 620 provides a relay between the first electrode terminal portion 610 and the first connection terminal portion 630. The first relay portion 620 has a substantially rectangular flat plate shape elongated in the Y-axis direction, and includes a first portion 620 athat extends in the X-axis negative direction from the end of the first electrode terminal portion 610 in the Z-axis positive direction and a second portion 620 bthat extends in the Z-axis positive direction from the end of the first portion 620 ain the X-axis negative direction. As the opposing portion included in the first bus bar 600, the first relay portion 620 of the first planar surface 531 of the circumferential surface 530 of the capacitor element 500 is from the X-axis negative side across the region between the first electrode 510 and the second electrode 520.On the first portion 620 aof the first relay portion 620, at positions closer to the first electrode 510 than to the second electrode 520 on the Z-axis negative side surface, two protrusions 621 are provided in a manner of being arranged in the Y-axis direction. Two protrusions 621 have a flat, substantially cylindrical shape, project from the first relay portion 620 toward the first planar surface 531 of the circumferential surface 530 of the capacitor element 500, and abut on the first plane 531. The distal end surface 621 athat abuts on the first planar surface 531 of each protrusion 621 has a flat shape.The first connection terminal portion 630 has a substantially rectangular flat plate shape that is elongated in the Y-axis direction and extends in the X-axis positive direction from the end of the second portion 620 bof the first relay portion 620 in the Z-axis positive direction.The second bus bar 700 is formed by cutting out a suitable shape from a conductive material such as a copper plate and then bending. The second bus bar 700 is therefore a single structure including a second electrode terminal portion 710, a second relay portion 720, and a second connection terminal portion 730.The second electrode terminal portion 710 has a substantially rectangular flat plate shape elongated in the Y-axis direction. The second electrode terminal portion 710 contacts the second electrode 520 of the capacitor element 500 from the X-axis negative side. The second electrode terminal portion 710 and the second electrode 520 are joined together by joining methods such as welding and soldering. Thus, the second bus bar 700 is electrically connected to the second electrode 520.The second relay portion 720 provides a relay between the second electrode terminal portion 710 and the second connection terminal portion 730. The second relay portion 720 has a substantially rectangular flat plate shape elongated in the Y-axis direction, and extends continuously from the second electrode terminal portion 710 in the positive Z-axis direction.The second connection terminal portion 730 has a substantially rectangular flat plate shape elongated in the Y-axis direction, and extends in the X-axis negative direction from the end of the second relay portion 720 in the Z-axis positive direction.The insulating member 800 is formed of an electric insulation material such as polyphenylene sulfide (PPS), and has a flat plate shape having an L-shaped cross section elongated in the Y-axis direction. The insulating member 800 is disposed between the first relay portion 620 and the second relay portion 720 on the second electrode 520 side, and is also disposed between the first relay portion 620 and the first planar surface 531 of the circumferential surface 530 of the capacitor element 500. In this way, insulation is ensured between the first relay portion 620 and both the second relay portion 720 and the second electrode 520.The thickness D 7 of the insulating member 800 is set equal to the protrusion length D 8 of the two protrusions 621 of the first relay portion 620 (see FIG. 12A ). Thus, the first planar surface 531 of the capacitor element 500 is parallel to the first relay portion 620. Between the first planar surface 531 and the first relay portion 620, a uniform gap S of a constant width (width for the thickness D 7 and the protrusion length D 8) is secured. By maintaining a constant distance between the capacitor element 500 and the first relay part 620, i.e. by reducing the variations in this distance, the electrical characteristics of the foil capacitor 2 are less likely to vary.The housing 50 is made of a resin material, for example, a thermoplastic resin such as polyphenylene sulfide (PPS). The housing 50 has a substantially rectangular box shape and includes a substantially rectangular opening 51, a substantially rectangular bottom portion 52 facing the opening 51, a substantially rectangular first side wall 53 and a second side wall 54 extending from both ends of the bottom portion 52 on the X-axis direction side toward the opening 51 (in the positive Z-axis direction) and facing each other, and a rectangular third side wall 55 and a fourth side wall 56 extending from both ends of the bottom portion 52 on the Y-axis direction side toward the opening 51 (in the positive Z-axis direction) and facing each other.Inside the housing 50, the capacitor element module 40 is disposed in a manner that the first electrode 510 and the second electrode 520 of the capacitor element 500 face the first side wall 53 and the second side wall 54 of the housing 50, respectively. The first relay portion 620 of the first bus bar 600 extends along the opening 51 of the housing 50 from the first side wall 53 side toward the second side wall 54, then bends and is led out to the outside of the filler resin 60, and the first connection terminal portion 630 of the first bus bar 600 is exposed from the filler resin 60. In addition, the second relay portion 720 of the second bus bar 700 is led out from the filler resin 60, and the second connection terminal portion 730 of the second bus bar 700 is exposed from the filler resin 60.The circumferential surface 530 of the capacitor element 500 and the first relay portion 620 are connected therebetween with the filler resin 60 existing in the gap S. At this time, a constant thickness is secured for the filler resin 60 in the gap S, and thus peeling is less likely to occur between the circumferential surface 530 of each capacitor element 500 and the filler resin 60 or between the first relay portion 620 and the filler resin 60. Also, since the gap S is less likely to become narrower, voids are less likely to occur in the filler resin 60 existing in the gap S. Therefore, moisture resistance deterioration due to moisture entering peeled portions or voids is less likely to occur, and therefore the moisture resistance of the sheet capacitor 2 can be improved.Note that, in the foil capacitor 2 of the present exemplary embodiment, the gap S between the circumferential surface 530 of the capacitor element 500 and the first relay portion 620 is closer to the opening 51 of the housing 50 as compared with the foil capacitor 1 of the first exemplary embodiment.The film capacitor 2 is mounted on the external device. Similarly to the first exemplary embodiment, the external terminal T 1 is connected to the first connection terminal portion 630 by welding, and the external terminal T 2 is connected to the second connection terminal portion 730 by welding.[Effects of Second Exemplary Embodiment]According to the second exemplary embodiment, similar effects to Effect 1 to Effect 4 and Effect 6 to Effect 8 described in the first exemplary embodiment can be obtained.Modification: ModificationAlthough the exemplary embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-mentioned exemplary embodiments, and the application examples of the present disclosure may be modified in various ways in addition to the above-mentioned exemplary embodiments.In the first exemplary embodiment or the second exemplary embodiment, the first relay portion 220, 620 of the first bus bar 200, 600 has, for example, two protrusions 221, 621 for a capacitor element 100, 500, but the first relay portion 220, 620 may have one or three or more protrusions 221, 621. Note that it is desirable that when a protrusion 221, 621 is provided, the protrusion 221, 621 is formed in a shape elongated in the direction perpendicular to the direction in which the first electrode 110, 510 and the second electrode 120, 520 are arranged (Y-axis direction), for example, in an elongated cylindrical shape.In addition, the protrusion 221, 621 has a cylindrical shape in the first or second exemplary embodiment. However, the protrusion 221, 621 may have any shape, for example, a prismatic shape.Moreover, in the first exemplary embodiment or the second exemplary embodiment, the protrusion 221, 621 and the insulating member 400, 800 are interposed in the gap S between the first planar surface 131, 531 of the capacitor element 100, 500 and the first relay portion 220, 620 of the first bus bar 200, 600. However, a configuration may be adopted in which only the protrusion 221, 621 is interposed in the gap S.Moreover, in the first exemplary embodiment or the second exemplary embodiment, the distal end surface 221 a, 621 aof the protrusion 221, 621 abutting on the first flat surface 131, 531 of the capacitor element 100, 500 is formed as a flat surface, but the distal end surface 221 a, 621 amay be formed as a surface other than a flat surface, such as an arc surface.Moreover, the configurations of the first bus bar 200, 600 and the second bus bar 300, 700 are not limited to the configurations shown in the first exemplary embodiment or the second exemplary embodiment, but may be any configuration.In the above first exemplary embodiment, the foil capacitor 1 includes four capacitor elements 100. In the above second exemplary embodiment, the foil capacitor 2 includes a capacitor element 500. However, the number of capacitor elements 100 and 500 may be changed as appropriate.In the first or second exemplary embodiment, the capacitor element 100, 500 is further formed by stacking two metallized films each having aluminum vapor-deposited on a dielectric film, and winding or laminating the stacked metallized films. Alternatively, the capacitor element 100, 500 may be formed by stacking a metallized film in which aluminum is vapor-deposited on both surfaces of a dielectric film and an insulation film, and by winding or laminating the metallized film and the insulation film.In the first exemplary embodiment or the second exemplary embodiment, the foil capacitor 1, 2 is mentioned as an example of the capacitor of the present disclosure. However, the present disclosure may be applied to capacitors other than the foil capacitor 1, 2.Moreover, various modifications may be made to the exemplary embodiments of the present disclosure as appropriate within the scope of the technical idea recited in the claims.(Supplementary Note)The above description of the exemplary embodiments discloses the following techniques.(Technique 1)A capacitor includes:a capacitor element including a first electrode formed on one end surface of the capacitor element, a second electrode formed on another end surface of the capacitor element, and a circumferential surface connecting the first electrode to the second electrode;a first bus bar and a second bus bar connected to the first electrode and the second electrode, respectively;a housing accommodating the capacitor element; anda filler resin in which the capacitor element, a part of the first bus bar, and a part of the second bus bar are embedded, the filler resin being filled inside the housing, wherein:the circumferential surface includes a planar surface,the first bus bar includes an opposing portion having a flat plate shape and facing the flat surface, andthe opposing portion includes a protrusion protruding toward the planar surface and abutting against the planar surface.According to this technique, it is possible to maintain a constant width of a gap S between the flat surface on the circumferential surface of the capacitor element and the opposing portion of the first bus bar by interposing the protrusion in the gap. Therefore, a constant thickness is secured for the filler resin existing in the gap, and thus peeling is less likely to occur between the peripheral surface and the filler resin or between the opposing portion and the filler resin. In addition, since the gap is less likely to become narrow, the liquid phase filler resin is more likely to flow into the gap, and voids are less likely to be formed in the filler resin existing in the gap. Therefore, moisture resistance deterioration due to moisture entering peeled portions or voids is less likely to occur, and therefore the moisture resistance of the capacitor can be improved.In addition, since variations in the distance between the circumferential surface of the capacitor element and the opposing portion of the first bus bar are less likely to occur, variations in the electrical characteristics of the capacitor are less likely to occur.(Technique 2)The capacitor according to Technique 1, wherein:the opposing portion faces the planar surface from the first electrode to the second electrode, andan insulating member is disposed between the planar surface and the opposing portion on a side near the second electrode.According to this technique, not only the protrusion but also the insulating member can maintain a constant width of the gap between the planar surface and the opposing portion.(Technique 3)The capacitor according to Technique 2, wherein the protrusion is provided on the opposing portion at a position closer to the first electrode than to the second electrode.According to this technique, the protrusion and the insulating member can be arranged in a balanced manner in a direction in which the first electrode and the second electrode are arranged, and thus it becomes easier to maintain a constant width of the gap over an entire area between the planar surface and the opposing portion.(Technique 4)The capacitor according to Technique 3, wherein:the housing includes an opening, a bottom portion facing the opening, and a side wall extending from an end of the bottom portion toward the opening, the capacitor element is disposed within the housing such that the first electrode faces the bottom portion, andthe opposing portion extends along the side wall within the housing.In a configuration in which the capacitor element is disposed inside the housing in a manner that the first electrode faces the bottom portion and the opposing portion extends along the side wall inside the housing, the gap between the planar surface and the opposing portion is located relatively far from the opening of the housing, and therefore, the filler resin is less likely to enter the gap compared to a configuration in which the gap is closer to the opening.However, according to this technique, when the gap between the planar surface and the opposing portion is relatively far from the opening of the housing, the interposition of the protrusion into the gap makes it easier for the filler resin to enter the gap, and therefore it is possible to effectively suppress the occurrence of voids in the filler resin present in the gap.(Technique 5)The capacitor according to any one of Technique 1 to Technique 4, wherein the protrusion includes a flat surface abutting on the flat surface.According to this technique, a load applied to the planar surface by the abutting contact of the protrusion is alleviated, making the capacitor element less susceptible to damage.(Technique 6)The capacitor according to any one of Technique 1 to Technique 5, wherein the opposing portion is parallel to the planar surface.According to this technique, the thickness of the filler resin existing in the gap can be made uniform between the flat surface and the opposing portion, thereby preventing the filler resin from becoming partially thin.(Technique 7)The capacitor according to Technique 6, wherein a thickness of the insulating member is equal to a protrusion length of the protrusion.According to this technique, the opposing portion and the planar surface are more likely to be parallel in the direction in which the first electrode and the second electrode are arranged.(Technique 8)The capacitor according to Technique 6 or Technique 7, wherein the opposing portion includes a plurality of protrusions arranged in a direction perpendicular to a direction of arrangement of the first electrode and the second electrode, the plurality of protrusions including the protrusion.According to this technique, the protrusions abut on the planar surface at a plurality of locations in the direction perpendicular to the direction in which the first electrode and the second electrode are arranged, and therefore the opposing portion and the planar surface are more likely to be parallel.Industrial applicabilityThe present disclosure is useful for capacitors used for various electronic devices, electric devices, industrial devices, electric components of vehicles, and the like.Reference Numerals in the Drawings1, 2 Foil capacitor (capacitor) 10, 40 capacitor element module 20, 50 housing 21 opening 22 lower portion 24 second side wall (side wall) 30, 60 filler resin 100, 500 capacitor element 110, 510 first electrode 120, 520 second electrode 130, 530 peripheral surface 131, 531 first planar surface (planar surface) 200, 600 first bus bar 220, 620 first relay portion (opposing portion) 221, 621 protrusion 221 a, 621 a distal end surface 300, 700 second bus bar 400, 800 insulation memberReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedJP 2018 / 051656

[0004]

Claims

A capacitor, comprising: a capacitor element including a first electrode disposed on one end surface of the capacitor element, a second electrode disposed on another end surface of the capacitor element, and a circumferential surface connecting the first electrode to the second electrode; a first bus bar and a second bus bar respectively connected to the first electrode and the second electrode; a housing accommodating the capacitor element; and a filler resin in which the capacitor element, a part of the first bus bar, and a part of the second bus bar are embedded, the filler resin being filled inside the housing, wherein: the circumferential surface includes a planar surface, the first bus bar includes an opposing portion having a planar plate shape and facing the planar surface, and the opposing portion includes a protrusion protruding toward the planar surface and abutting on the planar surface.The capacitor according to claim 1, wherein: the opposing portion faces the planar surface from the first electrode to the second electrode, and an insulating member is disposed between the planar surface and the opposing portion on a side near the second electrode.The capacitor according to claim 2, wherein the protrusion is provided on the opposing portion at a position closer to the first electrode than to the second electrode.The capacitor according to claim 3, wherein: the housing includes an opening, a bottom portion facing the opening, and a side wall extending from an end of the bottom portion toward the opening, the capacitor element is disposed inside the housing in a manner that the first electrode faces the bottom portion, and the opposite portion extends along the side wall inside the housing.The capacitor of claim 1, wherein the protrusion includes a planar surface that abuts the planar surface.The capacitor according to any one of claims 1 to 5, wherein the opposing portion is parallel to the planar surface.The capacitor according to claim 6, wherein a thickness of the insulation member is equal to a protrusion length of the protrusion.The capacitor according to claim 6, wherein the opposing portion includes a plurality of protrusions arranged in a direction perpendicular to a direction of arrangement of the first electrode and the second electrode, the plurality of protrusions including the protrusion.

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