Capacitor mounting structure and power conversion apparatus

Abstract

A capacitor mounting structure 1 comprises: a mounting substrate 10 that has a first main surface 10a and a second main surface 10b which oppose each other in the thickness direction; and a capacitor 20 that is disposed on the first main surface 10a of the mounting substrate 10. The capacitor 20 includes: a capacitor element 30 that has a first external electrode 31 and a second external electrode 32 on a surface of an element body 33; an exterior film 40 that accommodates the capacitor element 30 inside; and a first lead-out terminal 51 and a second lead-out terminal 52 that are electrically connected to the first external electrode 31 and the second external electrode 32, respectively, and that extend to the outside of the exterior film 40. The exterior film 40 includes a first film material 41 that covers one portion of the capacitor element 30, and a second film material 42 that covers the remaining portion of the capacitor element 30. A flange part 45 to which an outer edge of the first film material 41 and an outer edge of the second film material 42 are joined is provided on an outer edge of the exterior film 40. The first lead-out terminal 51 and the second lead-out terminal 52 are led out from between portions of the flange part 45 to the outside of the exterior film 40. At least one groove 15 is provided on the first main surface 10a of the mounting substrate 10. A portion of the flange part 45 including the first lead-out terminal 51 and the second lead-out terminal 52 is inserted into the groove part 15. The first lead-out terminal 51 and the second lead-out terminal 52 protrude from the second main surface 10b of the mounting substrate 10.

Description

Capacitor mounting structure and power conversion device

[0001] The present invention relates to a capacitor mounting structure and a power conversion device.

[0002] In a power conversion device that includes a power module composed of switching elements and a smoothing capacitor connected to the power module, there is a demand for reduction in size and weight and an increase in power density, and therefore there is a demand for reduction in size and weight and an increase in power density in the capacitors used in the power conversion device.

[0003] Patent Document 1 discloses a surface-mounted capacitor that is characterized by having a capacitor element with lead wires covered with a laminate film, and the laminate film attached to a fixing plate with external connection terminals, and the lead wires and the external connection terminals are fixedly attached. According to Patent Document 1, it is possible to reduce the height of the surface-mounted capacitor and the space it occupies on the board.

[0004] Japanese Patent Application Laid-Open No. 2005-93940

[0005] In laminate-cased capacitors (i.e., capacitors in which the capacitor element is casing a laminate film) such as those described in Patent Document 1, the exterior body is typically flexible in terms of material and structure. Therefore, unlike case-type capacitors in which the internal capacitor element is constrained by a rigid structure such as an exterior case, it is difficult to firmly secure the capacitor to the mounting board. Furthermore, unlike lead-type capacitors, it is difficult to accurately position the capacitor during mounting. Furthermore, in order to stabilize the capacitor as much as possible when mounting it to the mounting board, it is desirable to have the side of the capacitor with the largest surface area in contact with the mounting board, which can result in a large mounting area.

[0006] The present invention has been made to solve the above problems, and aims to provide a capacitor mounting structure that enables a capacitor to be firmly fixed to a mounting board, accurately positioned during mounting, and reduces the mounting area. Another aim of the present invention is to provide a power conversion device that includes the capacitor mounting structure.

[0007] The capacitor mounting structure of the present invention includes a mounting substrate having a first main surface and a second main surface opposing each other in a thickness direction, and a capacitor disposed on the first main surface of the mounting substrate. The capacitor includes a capacitor element having a first external electrode and a second external electrode on the surface of an element body, an exterior film that houses the capacitor element, and a first lead terminal and a second lead terminal electrically connected to the first external electrode and the second external electrode, respectively, and extending to the outside of the exterior film. The exterior film includes a first film material that covers a portion of the capacitor element, and a second film material that covers the remaining portion of the capacitor element. A flange portion is provided at the outer edge of the exterior film, where the outer edge of the first film material and the outer edge of the second film material are joined. The first lead terminal and the second lead terminal are extended to the outside of the exterior film between the flange portions. At least one groove portion is provided in the first main surface of the mounting substrate. The flange portion including the first and second lead terminals is inserted into the groove, and the first and second lead terminals protrude from the second main surface of the mounting substrate.

[0008] The power conversion device of the present invention comprises the capacitor mounting structure of the present invention, and a power module arranged on the second main surface of the mounting board and electrically connected to the capacitor via the first lead-out terminal and the second lead-out terminal.

[0009] According to the present invention, it is possible to provide a capacitor mounting structure that enables a capacitor to be firmly fixed to a mounting board, that enables accurate positioning during mounting, and that enables a small mounting area. Furthermore, according to the present invention, it is possible to provide a power conversion device that includes the capacitor mounting structure.

[0010] FIG. 1 is a perspective view schematically illustrating an example of a capacitor mounting structure according to a first embodiment of the present invention. FIG. 2 is an exploded perspective view of the capacitor mounting structure shown in FIG. 1. FIG. 3 is a perspective view schematically illustrating an example of a capacitor element constituting a capacitor. FIG. 4 is a cross-sectional view schematically illustrating an example of a capacitor element constituting a film capacitor. FIG. 5 is a perspective view schematically illustrating an example of an element body constituting the capacitor element shown in FIG. 4. FIG. 6 is a perspective view schematically illustrating another example of an element body constituting the capacitor element shown in FIG. 4. FIG. 7 is a perspective view schematically illustrating an example of a capacitor mounting structure according to a second embodiment of the present invention. FIG. 8 is an exploded perspective view of the capacitor mounting structure shown in FIG. 7. FIG. 9 is a perspective view schematically illustrating an example of a capacitor mounting structure according to a third embodiment of the present invention. FIG. 10 is a perspective view schematically illustrating an example of a capacitor mounting structure according to a fourth embodiment of the present invention. FIG. 11 is a perspective view schematically illustrating another example of a capacitor mounting structure according to the fourth embodiment of the present invention. FIG. 12 is a side view schematically illustrating an example of a power conversion device according to the present invention.

[0011] The capacitor mounting structure of the present invention will be described below. Note that the present invention is not limited to the following embodiments and may be modified as appropriate within the scope of the present invention. Furthermore, a combination of multiple individual preferred configurations described in the following embodiments also constitutes the present invention.

[0012] The following embodiments are merely examples, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible. From the second embodiment onwards, descriptions of matters common to the first embodiment will be omitted, and differences will be mainly described. In particular, similar effects resulting from similar configurations will not be mentioned one after the other for each embodiment.

[0013] In the following description, when no particular distinction is made between the embodiments, they will simply be referred to as "the capacitor mounting structure of the present invention."

[0014] In this specification, terms indicating the relationship between elements (e.g., "perpendicular," "parallel," "orthogonal," etc.) and terms indicating the shapes of elements are not expressions that only express a strict meaning, but are expressions that mean that they are substantially equivalent, for example, including a difference of about a few percent. Furthermore, in this specification, "equivalent" is not an expression that means only complete equivalent, but is an expression that means that they are substantially equivalent, for example, including a difference of about a few percent.

[0015] The drawings shown below are schematic diagrams, and the dimensions, aspect ratio, and other scales may differ from those of the actual product. In the drawings, the same or equivalent parts will be designated by the same reference numerals. In addition, the same elements will be designated by the same reference numerals in each drawing, and duplicate explanations will be omitted.

[0016] First Embodiment In a first embodiment of the present invention, one groove is provided on a first main surface of a mounting substrate.

[0017] Fig. 1 is a perspective view schematically showing an example of a capacitor mounting structure according to a first embodiment of the present invention. Fig. 2 is an exploded perspective view of the capacitor mounting structure shown in Fig. 1. Fig. 3 is a perspective view schematically showing an example of a capacitor element constituting a capacitor.

[0018] The capacitor mounting structure 1 shown in FIG. 1 includes a mounting substrate 10 and a capacitor 20 .

[0019] The mounting substrate 10 has a first main surface 10a and a second main surface 10b that face each other in the thickness direction.

[0020] The mounting substrate 10 may be a multilayer substrate or a single-layer substrate. The mounting substrate 10 may also be a ceramic substrate, a resin substrate, or an insulated metal substrate. The ceramic material constituting the ceramic substrate may be a low-temperature sintered ceramic material or a high-temperature sintered ceramic material. The resin material constituting the resin substrate may be a thermosetting resin or a thermoplastic resin, such as a glass epoxy resin or a liquid crystal polymer. The insulated metal substrate may include a metal plate such as aluminum, copper, or iron, and an oxide film formed by oxidizing the surface of the metal plate, or an insulating layer such as a highly insulating resin material laminated on the surface of the metal plate.

[0021] The capacitor 20 is disposed on the first main surface 10 a of the mounting substrate 10 .

[0022] The capacitor 20 includes a capacitor element 30 (see FIG. 3 ), an exterior film 40 , a first lead terminal 51 , and a second lead terminal 52 .

[0023] 3, the capacitor element 30 has a first external electrode 31 and a second external electrode 32 on the surface of an element body 33. In the example shown in FIG. 3, the first external electrode 31 and the second external electrode 32 are provided on both end surfaces of the element body 33.

[0024] The type of capacitor element 30 is not particularly limited, but may be, for example, a film capacitor.

[0025] The exterior film 40 accommodates the capacitor element 30 therein.

[0026] The exterior film 40 includes a first film material 41 that covers a portion of the capacitor element 30 and a second film material 42 that covers the remaining portion of the capacitor element 30 .

[0027] The outer edge of the exterior film 40 is provided with a flange portion 45 where the outer edge of the first film material 41 and the outer edge of the second film material 42 are joined together.

[0028] In the flange portion 45, for example, the surfaces of the first film material 41 and the second film material 42 are joined together by heat welding or adhesive.

[0029] The first and second lead-out terminals 51 and 52 are electrically connected to the first and second external electrodes 31 and 32 , respectively, and extend to the outside of the exterior film 40 .

[0030] The first lead-out terminal 51 and the second lead-out terminal 52 are led out from between the flange portions 45 to the outside of the exterior film 40 .

[0031] The first lead-out terminal 51 and the second lead-out terminal 52 are, for example, flat copper plates having a predetermined shape.

[0032] As shown in FIG. 2, one groove 15 is provided on the first main surface 10 a of the mounting substrate 10 .

[0033] In the capacitor mounting structure 1 shown in Fig. 1, the flange portion 45 including the first lead-out terminal 51 and the second lead-out terminal 52 is inserted into the groove portion 15 (see Fig. 2). Furthermore, the first lead-out terminal 51 and the second lead-out terminal 52 protrude from the second main surface 10b of the mounting substrate 10.

[0034] As described above, by inserting the flange portion 45 including the first lead-out terminal 51 and the second lead-out terminal 52 into the groove portion 15, the capacitor 20 can be mounted upright on the mounting substrate 10. This allows the capacitor 20 to be firmly fixed to the mounting substrate 10 and allows accurate positioning during mounting. Furthermore, because the capacitor 20 can be mounted upright on the mounting substrate 10, the mounting area per capacitor 20 can be reduced.

[0035] The groove portion 15 may penetrate the mounting substrate 10 in the thickness direction. In this case, as shown in FIG. 1 , the flange portion 45 including the first lead-out terminal 51 and the second lead-out terminal 52 may protrude from the second main surface 10 b of the mounting substrate 10.

[0036] Alternatively, the groove 15 does not have to penetrate the mounting substrate 10 in the thickness direction. In that case, it is sufficient that a hole communicating with the groove 15 is provided in the second main surface 10 b of the mounting substrate 10 so that the first lead-out terminal 51 and the second lead-out terminal 52 can protrude from the second main surface 10 b of the mounting substrate 10.

[0037] The width of the groove 15 may or may not be constant in the direction in which the groove 15 extends. The planar shape of the groove 15 as viewed in the thickness direction of the mounting substrate 10 is not particularly limited, and examples thereof include a rectangle, an ellipse, and the like.

[0038] The width of the groove 15 may or may not be constant in the thickness direction of the mounting substrate 10. For example, the groove 15 may have a tapered shape in the thickness direction of the mounting substrate 10. In that case, it is preferable that the width of the groove 15 decreases from the first main surface 10a to the second main surface 10b of the mounting substrate 10.

[0039] The width of the groove portion 15 may be equal to the maximum thickness of the flange portion 45 in the portion including the first lead-out terminal 51 and the second lead-out terminal 52, or may be greater than the maximum thickness of the flange portion 45 in the portion including the first lead-out terminal 51 and the second lead-out terminal 52.

[0040] The length of the groove portion 15 may be equal to the maximum length of the flange portion 45 in the portion including the first lead-out terminal 51 and the second lead-out terminal 52, or may be greater than the maximum length of the flange portion 45 in the portion including the first lead-out terminal 51 and the second lead-out terminal 52.

[0041] When the capacitor element 30 is a film capacitor, the element body 33 of the capacitor element 30 is a laminate including a metallized film having an internal electrode layer provided on at least one main surface of a dielectric film.

[0042] The laminate is, for example, in the form of a column with an elliptical cross section, and external electrodes formed by, for example, metal spraying (metallicon) are provided on both end faces in the direction of the central axis.

[0043] The laminate may be a roll in which the metallized film is rolled up in a laminated state.

[0044] Hereinafter, as an example of a film capacitor, a wound film capacitor in which a metallized film is wound in a laminated state will be described, but a laminated film capacitor in which a metallized film is laminated may also be used.

[0045] 4 is a cross-sectional view schematically showing an example of a capacitor element constituting a film capacitor, taken along line AA of the capacitor element shown in FIG.

[0046] 4 , the element body 33 is a laminate including a first metallized film 61 and a second metallized film 62. For example, the element body 33 is a wound body in which the first metallized film 61 and the second metallized film 62 are wound in a stacked state. A first external electrode 31 and a second external electrode 32 are provided on both end surfaces of the element body 33.

[0047] As shown in Figure 4, the first metallized film 61 comprises a first dielectric film 63 and a first internal electrode layer 65 provided on the surface of the first dielectric film 63, and the second metallized film 62 comprises a second dielectric film 64 and a second internal electrode layer 66 provided on the surface of the second dielectric film 64.

[0048] 4 , the first internal electrode layer 65 and the second internal electrode layer 66 face each other with the first dielectric film 63 or the second dielectric film 64 sandwiched therebetween. Furthermore, the first internal electrode layer 65 is electrically connected to the first external electrode 31, and the second internal electrode layer 66 is electrically connected to the second external electrode 32.

[0049] The first dielectric film 63 and the second dielectric film 64 may have different configurations, but preferably have the same configuration.

[0050] The first internal electrode layer 65 is formed on one surface of the first dielectric film 63 so as to reach one side edge but not the other side edge. On the other hand, the second internal electrode layer 66 is formed on one surface of the second dielectric film 64 so as to reach the other side edge but not the one side edge. The first internal electrode layer 65 and the second internal electrode layer 66 are made of, for example, an aluminum layer.

[0051] FIG. 5 is a perspective view schematically showing an example of an element body constituting the capacitor element shown in FIG.

[0052] 4 and 5, the first dielectric film 63 and the second dielectric film 64 are laminated with a shift relative to each other in the width direction (the left-right direction in FIG. 4) so ​​that the end of the first internal electrode layer 65 that reaches the side edge of the first dielectric film 63 and the end of the second internal electrode layer 66 that reaches the side edge of the second dielectric film 64 are both exposed from the laminated films. As shown in FIG. 5, the element body 33 becomes a wound body of metallized films by winding the first dielectric film 63 and the second dielectric film 64 in a laminated state, and is in a stacked state with the first internal electrode layer 65 and the second internal electrode layer 66 maintained in a state where they are exposed at their ends.

[0053] In Figures 4 and 5, the second dielectric film 64 is wound so that it is on the outside of the first dielectric film 63, and the first internal electrode layer 65 and the second internal electrode layer 66 of each of the first dielectric film 63 and the second dielectric film 64 are wound so that they face inward.

[0054] FIG. 6 is a perspective view schematically showing another example of the element body constituting the capacitor element shown in FIG.

[0055] When element body 33 of capacitor element 30 is formed from a wound body of metallized film, it is preferably pressed into a flattened shape such as an ellipse or oval in cross section, as shown in Figure 6, which is more compact than a true circle in cross section, allowing the entire film capacitor to be made smaller.

[0056] The roll of the metallized film may include a cylindrical winding shaft that is disposed on the central axis of the rolled metallized film and serves as the winding shaft when the metallized film is wound.

[0057] The first external electrode 31 and the second external electrode 32 are formed by thermally spraying, for example, zinc onto each end face of the element body 33 obtained as described above. The first external electrode 31 contacts the exposed end of the first internal electrode layer 65, and is thereby electrically connected to the first internal electrode layer 65. The second external electrode 32 contacts the exposed end of the second internal electrode layer 66, and is thereby electrically connected to the second internal electrode layer 66.

[0058] The exterior film 40 is, for example, a laminate film having a three-layer structure including, in order from the capacitor element 30 side, a first resin layer, a metal layer, and a second resin layer.

[0059] The first resin layer functions as a layer for heat-sealing laminate films together, for example, as a layer for heat-sealing the flange portion 45 of the exterior film 40 .

[0060] The first resin layer is preferably made of a polyolefin-based thermoplastic resin such as a polypropylene resin.

[0061] The metal layer acts as a layer to improve the barrier properties against moisture.

[0062] The metal layer is preferably composed of aluminum.

[0063] The second resin layer functions as a layer for protecting the metal layer and further improving the barrier properties against moisture.

[0064] The second resin layer is preferably made of a thermoplastic resin such as polyethylene terephthalate resin or nylon resin.

[0065] The first resin layer and the metal layer may be bonded with an adhesive or may be bonded by thermocompression.

[0066] The second resin layer and the metal layer may be bonded with an adhesive or may be bonded by thermocompression.

[0067] The number of layers of the exterior film 40 is not particularly limited as long as it has a thermoplastic resin layer on the surface on the capacitor element 30 side, and it may be one layer, two layers, or three or more layers.

[0068] Second Embodiment In a second embodiment of the present invention, a plurality of grooves are provided in parallel on a first main surface of a mounting substrate, and a plurality of capacitors are arranged side by side on the first main surface of the mounting substrate, thereby achieving high-density mounting of capacitors.

[0069] Fig. 7 is a perspective view schematically showing an example of a capacitor mounting structure according to a second embodiment of the present invention, and Fig. 8 is an exploded perspective view of the capacitor mounting structure shown in Fig. 7.

[0070] In the capacitor mounting structure 2 shown in Fig. 7, a plurality of grooves 15 are provided in parallel on the first main surface 10a of the mounting substrate 10 as shown in Fig. 8. The plurality of grooves 15 are arranged, for example, such that one end of each groove 15 faces each other and the other end faces each other. The number of grooves 15 is not particularly limited as long as it is two or more.

[0071] A flange portion 45 including a first lead-out terminal 51 and a second lead-out terminal 52 is inserted into each groove 15. Furthermore, the first lead-out terminal 51 and the second lead-out terminal 52 protrude from the second main surface 10b of the mounting substrate 10. In the example shown in Figures 7 and 8, one capacitor 20 is arranged per groove 15.

[0072] As a result, a plurality of capacitors 20 are arranged side by side on the first main surface 10a of the mounting substrate 10. In the example shown in Fig. 7, the capacitors 20 are arranged so that their side surfaces face each other. The configurations of the capacitors 20 may be the same, or some or all of them may be different.

[0073] Except for the above-mentioned configuration, the capacitor mounting structure 2 shown in FIG. 7 may have a common configuration with the capacitor mounting structure 1 shown in FIG.

[0074] Although there are no particular limitations on the spacing between the grooves 15, it is preferable that the spacing between adjacent grooves 15 is equal. In this case, it is preferable that the spacing between at least one pair of adjacent grooves 15 is equal, and it is more preferable that the spacing between all adjacent grooves 15 is equal.

[0075] The widths of the grooves 15 may be the same or some or all of them may be different. Similarly, the lengths of the grooves 15 may be the same or some or all of them may be different.

[0076] In a third embodiment of the present invention, the width of the groove is equal to the maximum thickness of the flange portion including the first and second lead-out terminals, or the length of the groove is equal to the maximum length of the flange portion including the first and second lead-out terminals, or both, which allows for easy and accurate positioning of the capacitor on the mounting board.

[0077] FIG. 9 is a perspective view schematically showing an example of a capacitor mounting structure according to a third embodiment of the present invention.

[0078] In the capacitor mounting structure 3 shown in Figure 9, the width of the groove portion 15 is equivalent to the maximum thickness of the flange portion 45 in the portion including the first lead-out terminal 51 and the second lead-out terminal 52, and the length of the groove portion 15 is equivalent to the maximum length of the flange portion 45 in the portion including the first lead-out terminal 51 and the second lead-out terminal 52.

[0079] 9 may satisfy only one of the requirements. That is, the width of groove 15 may be equal to the maximum thickness of flange 45 in the portion including first and second lead-out terminals 51 and 52, and the length of groove 15 may be greater than the maximum length of flange 45 in the portion including first and second lead-out terminals 51 and 52. Alternatively, the width of groove 15 may be greater than the maximum thickness of flange 45 in the portion including first and second lead-out terminals 51 and 52, and the length of groove 15 may be equal to the maximum length of flange 45 in the portion including first and second lead-out terminals 51 and 52.

[0080] Except for the above-mentioned configuration, the capacitor mounting structure 3 shown in FIG. 9 may have a configuration common to the capacitor mounting structure 1 shown in FIG. 1 or the capacitor mounting structure 2 shown in FIG.

[0081] [Fourth Embodiment] In a fourth embodiment of the present invention, a capacitor mounting structure further includes a cover that covers a flange portion that protrudes from the second main surface of the mounting substrate. This makes it possible to reinforce the flange portion. Furthermore, when a resin such as an epoxy resin is used to strengthen the capacitor mounting, it is possible to prevent resin leakage from the groove.

[0082] FIG. 10 is a perspective view schematically showing an example of a capacitor mounting structure according to a fourth embodiment of the present invention.

[0083] The capacitor mounting structure 4 shown in FIG. 10 further includes a cover 55 that covers the flange portion 45 (see FIG. 1) that protrudes from the second main surface 10 b of the mounting substrate 10 .

[0084] The shape of the cover 55 is not limited, and may be, for example, a rectangular parallelepiped. Although not shown, the cover 55 has grooves therethrough into which the flange portion 45, the first lead-out terminal 51, and the second lead-out terminal 52 can be inserted.

[0085] The material of the cover 55 is not particularly limited as long as it has insulating properties.

[0086] FIG. 11 is a perspective view schematically showing another example of a capacitor mounting structure according to the fourth embodiment of the present invention.

[0087] The capacitor mounting structure 4A shown in FIG. 11 further includes a cover 55A that covers the flange portion 45 that protrudes from the second main surface 10b of the mounting substrate 10.

[0088] The cover 55A has a base 56 that supports the first lead-out terminal 51 and the second lead-out terminal 52 from one side. The shape of the base 56 is not particularly limited.

[0089] Except for the above-mentioned configuration, the capacitor mounting structure 4 shown in Fig. 10 and the capacitor mounting structure 4A shown in Fig. 11 may have a configuration common to the capacitor mounting structure 1 shown in Fig. 1, the capacitor mounting structure 2 shown in Fig. 7, or the capacitor mounting structure 3 shown in Fig. 9. When multiple capacitors are arranged on a mounting board, it is sufficient that at least one capacitor is provided with a cover. Furthermore, when multiple capacitors are provided with covers, the configurations of the covers may be the same, or some or all of them may be different.

[0090] The capacitor mounting structure of the present invention is preferably used as a smoothing capacitor that constitutes a power converter. Such a power converter also constitutes the present invention.

[0091] FIG. 12 is a side view schematically showing an example of a power conversion device of the present invention.

[0092] The power conversion device 100 shown in FIG. 12 includes a capacitor mounting structure 110 and a power module 120 .

[0093] The capacitor mounting structure 110 is a capacitor mounting structure of the present invention. In the example shown in Fig. 12, the configuration of the capacitor mounting structure 110 is the same as the configuration of the capacitor mounting structure 1 shown in Fig. 1, except that the shapes of the first lead-out terminal 51 and the second lead-out terminal 52 are different.

[0094] The power module 120 is disposed on the second main surface 10 b of the mounting substrate 10 and is electrically connected to the capacitor 20 via the first lead terminal 51 and the second lead terminal 52 .

[0095] In the example shown in FIG. 12, the terminals on the capacitor 20 side are bent, but the terminals on the power module 120 side may also be bent.

[0096] Although not shown in FIG. 12, the power module 120 includes a plurality of power devices such as IGBTs, MOSFETs, and the like.

[0097] 12, the capacitor 20 and the power module 120 are arranged on different main surfaces of the mounting substrate 10, which contributes to area saving compared to a structure in which the capacitor 20 and the power module 120 are arranged on the same main surface of the mounting substrate 10. Note that the height of the entire device can be controlled by adjusting the size of the capacitor 20.

[0098] The power conversion device of the present invention is used, for example, in a motor drive inverter mounted on an electric vehicle.

[0099] The capacitor mounting structure of the present invention is not limited to the above-described embodiment, and various applications and modifications can be made within the scope of the present invention with respect to the configurations of the mounting substrate and capacitor, manufacturing conditions, etc.

[0100] For example, in the capacitor, the shape, arrangement, number, etc. of the capacitor elements are not limited to those in the above embodiment. Similarly, the shape, arrangement, number, etc. of the lead-out terminals are not limited to those in the above embodiment.

[0101] When the capacitor element is a film capacitor, the dielectric film constituting the element body may contain a curable resin as a main component, or may contain a thermoplastic resin as a 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 a main component.

[0102] In this specification, the term "major component of the dielectric film" refers to the component with the largest weight percentage, preferably the component with a weight percentage of more than 50 wt %. Therefore, the dielectric film may contain components other than the major component, such as additives such as silicone resin, and uncured portions of starting materials such as the first organic material and second organic material described below.

[0103] The curable resin may be a thermosetting resin or a photocurable resin.

[0104] In this specification, thermosetting resin means a resin that can be cured by heat, and the curing method is not limited. Therefore, as long as it is a resin that can be cured by heat, resins that are cured by methods other than heat (for example, light, electron beam, etc.) are also included in thermosetting resins. Furthermore, depending on the material, a reaction may be initiated due to the reactivity of the material itself, and resins that proceed to cure without necessarily applying heat or light from the outside are also considered thermosetting resins. The same applies to photocurable resins, and the curing method is not limited.

[0105] The curable resin may or may not have at least one of a urethane bond and a urea bond. Examples of such resins include a urethane resin having a urethane bond and a urea resin having a urea bond. Alternatively, the curable resin may be a resin having both a urethane bond and a urea bond.

[0106] The presence of urethane bonds and / or urea bonds can be confirmed using a Fourier transform infrared spectrophotometer (FT-IR).

[0107] The curable resin is preferably a cured product of a first organic material and a second organic material, such as a cured product obtained by reacting a hydroxyl group (OH group) of the first organic material with an isocyanate group (NCO group) of the second organic material.

[0108] 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 an isocyanate group and a hydroxyl group. In this case, the dielectric film may contain either an isocyanate group or a hydroxyl group, or may contain both an isocyanate group and a hydroxyl group.

[0109] The presence of an isocyanate group and / or a hydroxyl group can be confirmed using a Fourier transform infrared spectrophotometer (FT-IR).

[0110] The first organic material is preferably a polyol having multiple hydroxyl groups in the molecule. Examples of polyols include polyether polyol, polyester polyol, and polyvinyl acetal. Two or more organic materials may be used in combination as the first organic material.

[0111] The second organic material is preferably an isocyanate compound, an epoxy resin, or a melamine resin having multiple functional groups in the molecule. Two or more organic materials may be used in combination as the second organic material. Among the second organic materials, an isocyanate compound is preferred.

[0112] Examples of the isocyanate compound include aromatic polyisocyanates such as diphenylmethane diisocyanate (MDI) and tolylene diisocyanate (TDI), and aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI). Modified products of these polyisocyanates, such as modified products having carbodiimide or urethane, may also be used.

[0113] The epoxy resin is not particularly limited as long as it is a resin having an epoxy ring, and examples thereof include bisphenol A type epoxy resin, biphenyl skeleton epoxy resin, cyclopentadiene skeleton epoxy resin, and naphthalene skeleton epoxy resin.

[0114] 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 on the periphery thereof, and examples thereof include alkylated melamine resins, etc. Modified melamine resins may also be used.

[0115] The dielectric film constituting the element body of the capacitor element is preferably obtained by forming a resin solution containing the first organic material and the second organic material into a film, and then curing it by heat treatment.

[0116] The dielectric film constituting the element body of the capacitor element may contain a vapor-deposited polymer film as a main component. The vapor-deposited polymer film may or may not have at least one of a urethane bond and a urea bond.

[0117] The vapor deposition polymerized film refers to a film formed by vapor deposition polymerization, and is basically included in the category of curable resins.

[0118] The dielectric film constituting the element body of the capacitor element may contain a thermoplastic resin as a main component, such as polypropylene, polyethersulfone, polyetherimide, or polyarylate.

[0119] The dielectric film constituting the capacitor element body may also contain additives to impart other functions. For example, adding a leveling agent can provide smoothness. The additive is preferably a material having a functional group reactive with a hydroxyl group and / or an isocyanate group and forming 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.

[0120] The thickness of the dielectric film constituting the element body of the capacitor element is not particularly limited, but may be set appropriately according to the required capacitance and required element volume of the capacitor to be fabricated.

[0121] The thickness of the dielectric film can be measured using an optical film thickness meter.

[0122] When the capacitor element is a film capacitor, the type of metal contained in the internal electrode layer constituting the element body is not particularly limited, but it is preferable that the metal layer contains any one selected from the group consisting of aluminum (Al), titanium (Ti), zinc (Zn), magnesium (Mg), tin (Sn), and nickel (Ni).

[0123] The thickness of the internal electrode layer constituting the element body of the capacitor element is not particularly limited, but from the viewpoint of suppressing damage to the internal electrode layer, the thickness of the internal electrode layer is preferably 5 nm or more and 40 nm or less.

[0124] The thickness of the internal electrode layer can be determined by observing a cross section of the metallized film cut in the thickness direction using an electron microscope such as a field emission scanning electron microscope (FE-SEM).

[0125] The present specification discloses the following:

[0126] <1> A mounting substrate having a first main surface and a second main surface opposed to each other in a thickness direction, and a capacitor disposed on the first main surface of the mounting substrate, wherein the capacitor includes a capacitor element having a first external electrode and a second external electrode on a surface of an element body, an exterior film accommodating the capacitor element, and a first lead-out terminal and a second lead-out terminal electrically connected to the first external electrode and the second external electrode, respectively, and extending to the outside of the exterior film, wherein the exterior film includes a first film material covering a part of the capacitor element and a second film material covering the remaining part of the capacitor element, wherein a flange portion is provided on an outer edge of the exterior film, where the outer edge of the first film material and the outer edge of the second film material are joined, and the first lead-out terminal and the second lead-out terminal are led to the outside of the exterior film from between the flange portions, and wherein at least one groove portion is provided on the first main surface of the mounting substrate, the flange portion including the first lead-out terminal and the second lead-out terminal is inserted into the groove, and the first lead-out terminal and the second lead-out terminal protrude from the second main surface of the mounting substrate.

[0127] <2> The capacitor mounting structure according to <1>, wherein the groove penetrates the mounting substrate in the thickness direction, and the flange portion including the first lead terminal and the second lead terminal protrudes from the second main surface of the mounting substrate.

[0128] <3> The capacitor mounting structure according to <2>, further comprising a cover that covers the flange portion that protrudes from the second main surface of the mounting board.

[0129] <4> The capacitor mounting structure according to any one of <1> to <3>, wherein a plurality of the grooves are provided in parallel on the first main surface of the mounting substrate, and a plurality of the capacitors are arranged side by side on the first main surface of the mounting substrate.

[0130] <5> The capacitor mounting structure according to <4>, wherein the intervals between adjacent grooves are equal.

[0131] <6> The capacitor mounting structure according to any one of <1> to <5>, wherein the width of the groove is equal to the maximum thickness of the flange portion in a portion including the first lead terminal and the second lead terminal.

[0132] <7> The capacitor mounting structure according to any one of <1> to <5>, wherein the length of the groove is equal to the maximum length of the flange portion including the first lead terminal and the second lead terminal.

[0133] <8> The capacitor mounting structure according to any one of <1> to <5>, wherein the width of the groove is equal to the maximum thickness of the flange portion including the first and second lead-out terminals, and the length of the groove is equal to the maximum length of the flange portion including the first and second lead-out terminals.

[0134] <9> The capacitor mounting structure according to any one of <1> to <8>, wherein the element body of the capacitor element is a laminate or a wound body including a metallized film having an internal electrode layer provided on at least one main surface of a dielectric film.

[0135] <10> A power conversion device comprising: the capacitor mounting structure according to any one of <1> to <9>; and a power module that is disposed on the second main surface of the mounting board and is electrically connected to the capacitor via the first lead-out terminal and the second lead-out terminal.

[0136] DESCRIPTION OF SYMBOLS 1, 2, 3, 4, 4A Capacitor mounting structure 10 Mounting substrate 10a First main surface 10b Second main surface 15 Groove portion 20 Capacitor 30 Capacitor element 31 First external electrode 32 Second external electrode 33 Element body 40 Exterior film 41 First film material 42 Second film material 45 Flange portion 51 First lead-out terminal 52 Second lead-out terminal 55, 55A Cover 56 Base portion 61 First metallized film 62 Second metallized film 63 First dielectric film 64 Second dielectric film 65 First internal electrode layer 66 Second internal electrode layer 100 Power conversion device 110 Capacitor mounting structure 120 Power module

Claims

1. A mounting substrate having a first main surface and a second main surface opposed to each other in a thickness direction, and a capacitor disposed on the first main surface of the mounting substrate, wherein the capacitor includes a capacitor element having a first external electrode and a second external electrode on a surface of an element body, an exterior film housing the capacitor element, and a first lead-out terminal and a second lead-out terminal electrically connected to the first external electrode and the second external electrode, respectively, and extending to the outside of the exterior film, wherein the exterior film includes a first film material covering a portion of the capacitor element, and a second film material covering the remaining portion of the capacitor element, wherein an outer edge of the exterior film is provided with a flange portion where an outer edge of the first film material and an outer edge of the second film material are joined, and the first lead-out terminal and the second lead-out terminal are led out to the outside of the exterior film from between the flange portions, and at least one groove portion is provided on the first main surface of the mounting substrate, and a portion of the flange portion including the first lead-out terminal and the second lead-out terminal is inserted into the groove, the first lead-out terminal and the second lead-out terminal protrude from the second main surface of the mounting substrate.

2. A capacitor mounting structure as described in claim 1, wherein the groove portion penetrates the mounting substrate in the thickness direction, and the flange portion including the first lead-out terminal and the second lead-out terminal protrudes from the second main surface of the mounting substrate.

3. The capacitor mounting structure according to claim 2, further comprising a cover that covers the flange portion that protrudes from the second main surface of the mounting board.

4. The capacitor mounting structure according to any one of claims 1 to 3, wherein a plurality of the grooves are provided in parallel on the first main surface of the mounting substrate, and a plurality of the capacitors are arranged side by side on the first main surface of the mounting substrate.

5. The capacitor mounting structure according to claim 4, wherein the intervals between adjacent grooves are equal.

6. A capacitor mounting structure according to any one of claims 1 to 5, wherein the width of the groove is equal to the maximum thickness of the flange portion including the first lead-out terminal and the second lead-out terminal.

7. A capacitor mounting structure according to any one of claims 1 to 5, wherein the length of said groove is equal to the maximum length of said flange portion including said first lead-out terminal and said second lead-out terminal.

8. A capacitor mounting structure as claimed in any one of claims 1 to 5, wherein the width of the groove is equivalent to the maximum thickness of the flange portion including the first and second lead-out terminals, and the length of the groove is equivalent to the maximum length of the flange portion including the first and second lead-out terminals.

9. A capacitor mounting structure according to any one of claims 1 to 8, wherein the element body of the capacitor element is a laminate or wound body including a metallized film having an internal electrode layer provided on at least one main surface of a dielectric film.

10. A power conversion device comprising: a capacitor mounting structure according to any one of claims 1 to 9; and a power module disposed on the second main surface of the mounting board and electrically connected to the capacitor via the first lead-out terminal and the second lead-out terminal.

Images