Capacitor module

Abstract

To provide a capacitor module is provided that can reduce the distance between a pair of bus bars while increasing the positional accuracy of the pair of bus bars relative to a connection object such as a substrate or device.SOLUTION: A capacitor module 1 includes a capacitor element 10 having a first external electrode 12a and a second external electrode 12b, an outer case 20 in which the capacitor element 10 is housed, a first bus bar 30a electrically connected to the first external electrode 12a and drawn out to the outside of the outer case 20, a second bus bar 30b electrically connected to the second external electrode 12b and drawn out to the outside of the outer case 20, and an insulator 40 covering a portion of each of the first bus bar 30a and the second bus bar 30b, and the insulator 40 is molded integrally with the first bus bar 30a and the second bus bar 30b.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a capacitor module. [Background technology]

[0002] Patent Document 1 describes a bus bar structure for a capacitor including: a capacitor element having a pair of electrodes of opposite polarity at both axial ends; first and second plate-like bus bars each having a side plate portion extending from a base end connected to the electrodes of the capacitor element and disposed along a side surface of the capacitor element; an opposing plate portion extending upright from the side plate portion; and an external connection terminal portion extending from the opposing plate portion; an insulator interposed between the pair of opposing plate portions of the bus bars in a state where the pair of opposing plate portions are close to each other and opposed to each other; and a molded resin covering the entire capacitor element and the base end and side plate portions of the pair of bus bars, wherein the insulator is disposed between one of the pair of bus bars. the external connection terminals extending from the one opposing plate portion protrude upward from an end of the insulator, and the opposing surface of the opposing plate portion of the other bus bar that faces the one bus bar abuts against the back surface of the insulator.

[0003] Patent Document 2 discloses a capacitor comprising: a capacitor case having a bottom and an opening; a capacitor element housed in the capacitor case and having a first electrode E1 and a second electrode E2; a first terminal T1 connected to the first electrode E1; a second terminal T2 connected to the second electrode E2 and having an opposing portion opposing the first terminal T1; and an insulating member interposed between the first terminal T1 and the second terminal T2 and including an insulating plate that insulates at least the opposing portion from the first terminal T1, wherein the first terminal T1 and the second terminal T2 each have an extension portion TE extending to the outside of the capacitor case, the capacitor case has a fixing portion A that fixes the insulating plate, and the insulating member has a fixing portion B1 that fits with the fixing portion A and a fixing portion B2 that fixes at least one of the first terminal T1 and the second terminal T2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-153120 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-152243 Summary of the Invention [Problem to be solved by the invention]

[0005] In a capacitor module in which capacitor elements are housed inside an exterior case, a bus bar electrically connected to the external electrodes of the capacitor elements is generally drawn out of the exterior case and connected to a connection object such as a substrate, a device, etc. When connecting the bus bar to the connection object in this manner, particularly when laser welding the bus bar to the connection object, it is necessary to increase the positional accuracy of the bus bar relative to the connection object in order to facilitate connection of the bus bar to the connection object and ensure connection between the bus bar and the connection object.

[0006] However, when connecting a busbar to an object to be connected, it is difficult to increase the positional accuracy of the busbar relative to the object to be connected, for reasons such as variations in the size (e.g., dimensions) of the busbar when manufacturing the busbar (e.g., by sheet metal processing) and distortion of the busbar when connecting the busbar to the external electrode of the capacitor element (e.g., by welding).

[0007] On the other hand, capacitor modules generally use a pair of bus bars that are individually electrically connected to external electrodes with opposite polarities. When using a pair of bus bars with opposite polarities, it is necessary to reduce the distance between the pair of bus bars and thereby reduce the equivalent series inductance (ESL) of the pair of bus bars in order to improve the characteristics of the capacitor module.

[0008] However, if the distance between the pair of bus bars is too small, there is a risk of short-circuiting between the pair of bus bars. One possible way to prevent short-circuiting between the pair of bus bars is to insert insulating paper, an insulating plate, or the like between the pair of bus bars. However, inserting insulating paper, an insulating plate, or the like between the pair of bus bars when the distance between them is small is difficult, whether manually or automatically, due to warping and wrinkles caused by the thinness of the insulating paper, insulating plate, or the like. Furthermore, the insertion of insulating paper, an insulating plate, or the like between the pair of bus bars may cause, for example, the following problems. When inserting insulating paper, an insulating plate, or the like between the pair of bus bars manually, the increased work time may reduce the manufacturing efficiency of the capacitor module, or the quality of the capacitor module may be reduced if the work is overlooked. Furthermore, when inserting insulating paper, an insulating plate, or the like between the pair of bus bars automatically, there is a risk of reducing the quality of the capacitor module due to the extra space (margin) that is created between the pair of bus bars. For these reasons, it is difficult to reduce the distance between the pair of bus bars.

[0009] For these reasons, conventional capacitor modules have room for improvement in terms of increasing the positional accuracy of the pair of bus bars relative to the connection object such as a substrate or device, while reducing the distance between the pair of bus bars.

[0010] For example, in the busbar structure of a capacitor described in Patent Document 1, the insulator is integrated with only the opposing plate portion of one of a pair of busbars by insert molding, which is said to ensure that the relative positional relationship, positional accuracy, and dimensional accuracy between the opposing plate portion and the insulator are as accurate as desired.

[0011] However, with the capacitor busbar structure described in Patent Document 1, there are limitations to how accurately the busbar can be positioned relative to a connection target such as a substrate or device, particularly for the other busbar that is not integrated with the insulator. This is due to factors such as variations in busbar size during fabrication and distortion of the busbar when connected to the electrodes of the capacitor element. Furthermore, with the capacitor busbar structure described in Patent Document 1, as shown in FIG. 1 of Patent Document 1, only one busbar is integrated with the insulator, i.e., neither of the pair of busbars is integrated with the insulator, which limits how quickly the distance between the pair of busbars can be reduced.

[0012] Furthermore, in the capacitor described in Patent Document 2, the capacitor case has a fixing portion A that fixes the insulating plate, and the insulating member has a fixing portion B1 that fits with the fixing portion A and a fixing portion B2 that fixes at least one of the first terminal T1 and the second terminal T2, thereby improving the positional accuracy of each terminal relative to the capacitor element as well as the positional accuracy of each terminal relative to the capacitor case.

[0013] However, in the capacitor described in Patent Document 2, there is a limit to how accurately the first terminal T1 and the second terminal T2 can be positioned relative to a connection target such as a substrate or device, due to factors such as variations in the size of the terminals when they are fabricated and distortion of the terminals when they are connected to the electrodes of the capacitor element. Furthermore, as shown in Figure 2 of Patent Document 2, the capacitor described in Patent Document 2 is configured such that the insulating member (insulating plate) is inserted between the first terminal T1 and the second terminal T2 while being separated (independent) from the first terminal T1 and the second terminal T2, which makes it difficult to insert the insulating member (insulating plate) between the first terminal T1 and the second terminal T2, and therefore there is a limit to how quickly the distance between the first terminal T1 and the second terminal T2 can be reduced.

[0014] The present invention has been made to solve the above problems, and aims to provide a capacitor module that can reduce the distance between a pair of bus bars while improving the positional accuracy of the pair of bus bars relative to a connection object such as a board or device. [Means for solving the problem]

[0015] A capacitor module of the present invention includes a capacitor element having a first external electrode and a second external electrode, an outer case in which the capacitor element is housed, a first bus bar electrically connected to the first external electrode and extended to the outside of the outer case, a second bus bar electrically connected to the second external electrode and extended to the outside of the outer case, and an insulator covering a portion of each of the first bus bar and the second bus bar, wherein the insulator is molded integrally with the first bus bar and the second bus bar. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a capacitor module that can reduce the distance between a pair of bus bars while increasing the positional accuracy of the pair of bus bars relative to a connection object such as a substrate or device. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view schematically showing an example of a capacitor module of the present invention. [Figure 2] FIG. 2 is a perspective view schematically showing the capacitor module (excluding the filled resin) shown in FIG. 1 as seen through the exterior case. [Figure 3] FIG. 3 is a perspective view that schematically illustrates the capacitor element shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view schematically showing an example of a cross section of the capacitor element shown in FIG. 3 taken along line a1-a2. [Figure 5] FIG. 5 is a perspective view that schematically shows the exterior case shown in FIG. [Figure 6] FIG. 6 is a perspective view that schematically illustrates the first bus bar, the second bus bar, and the insulators shown in FIG. [Figure 7] FIG. 7 is an enlarged perspective view schematically illustrating the capacitor module shown in FIG. 2 as viewed from one side in the first direction. [Figure 8] FIG. 8 is an enlarged perspective view schematically illustrating the capacitor module shown in FIG. 2 as viewed from the other side in the first direction. [Figure 9] FIG. 9 is a graph showing the results of a simulation evaluation of the frequency characteristics of the equivalent series inductance of the capacitor module shown in FIG. 1 etc. while changing the shortest distance between the first bus bar and the second bus bar. DETAILED DESCRIPTION OF THE INVENTION

[0018] A capacitor module of the present invention includes a capacitor element having a first external electrode and a second external electrode, an outer case in which the capacitor element is housed, a first bus bar electrically connected to the first external electrode and extended to the outside of the outer case, a second bus bar electrically connected to the second external electrode and extended to the outside of the outer case, and an insulator covering a portion of each of the first bus bar and the second bus bar, wherein the insulator is molded integrally with the first bus bar and the second bus bar.

[0019] In the capacitor module of the present invention, the insulator is molded integrally with the first bus bar and the second bus bar, so that the first bus bar and the second bus bar are fixed to the insulator with high positional accuracy. In other words, in the capacitor module of the present invention, the insulator is molded integrally with the first bus bar and the second bus bar, so that the first bus bar and the second bus bar are positioned with high positional accuracy relative to the insulator. For these reasons, the capacitor module of the present invention can improve the positional accuracy of the first bus bar and the second bus bar relative to a connection object such as a board or device.

[0020] Furthermore, in the capacitor module of the present invention, the insulator is integrally molded with the first and second bus bars, so that the insulator is interposed between the first and second bus bars. In other words, when manufacturing the capacitor module of the present invention, the insulator can be interposed between the first and second bus bars simply by molding the insulator integrally with the first and second bus bars. This eliminates the need to insert insulating paper, insulating plates, or the like that are separate (independent) from the first and second bus bars between the first and second bus bars, as in the capacitor described in Patent Document 2, for example. Therefore, when manufacturing the capacitor module of the present invention, by integrally molding the insulator with the first and second bus bars, it is easy to interpose the insulator between the first and second bus bars even if the distance between the first and second bus bars is reduced. For these reasons, the capacitor module of the present invention allows the distance between the first and second bus bars to be reduced.

[0021] As described above, the capacitor module of the present invention makes it possible to reduce the distance between the first bus bar and the second bus bar while increasing the positional accuracy of the first bus bar and the second bus bar relative to the connection object such as a substrate or device.

[0022] Specific examples of the capacitor module of the present invention are described below. Note that the present invention is not limited to the following configurations and may be modified as appropriate without departing from the spirit of the present invention. Furthermore, a combination of multiple individual preferred configurations described below also constitutes the present invention.

[0023] In the following, a film capacitor will be shown as an example of a capacitor element of the capacitor module of the present invention, but the capacitor module of the present invention can also be applied to capacitor elements other than film capacitors.

[0024] The drawings shown below are schematic diagrams, and the dimensions, aspect ratio, scale, etc. may differ from those of the actual product.

[0025] In this specification, unless otherwise specified, terms indicating the relationship between elements (e.g., "parallel," "perpendicular," etc.) and terms indicating the shape of elements not only mean the literal strict form, but also mean a range that is substantially equivalent, for example, a range that includes a difference of about a few percent.

[0026] Fig. 1 is a perspective view schematically showing an example of a capacitor module of the present invention, and Fig. 2 is a perspective view schematically showing the capacitor module shown in Fig. 1 (excluding the filled resin) as seen through the exterior case.

[0027] The capacitor module 1 shown in FIGS. 1 and 2 includes a capacitor element 10, an outer case 20, a first bus bar 30a, a second bus bar 30b, and an insulator 40.

[0028] In FIG. 1 and other figures, the first direction D1, the second direction D2, and the third direction D3 are perpendicular to one another.

[0029] Fig. 3 is a perspective view schematically illustrating an example of the capacitor element illustrated in Fig. 2. Fig. 4 is a cross-sectional view schematically illustrating an example of a cross section of the capacitor element illustrated in Fig. 3 taken along line a1-a2.

[0030] As shown in FIGS. 3 and 4, capacitor element 10 has element body 11, first external electrode 12a, and second external electrode 12b.

[0031] Body 11 is a wound body in which first metallized film 13a and second metallized film 13b are wound in a stacked state in first direction D1. In other words, capacitor element 10 is a wound-type film capacitor in which metallized films are wound in a stacked state.

[0032] Capacitor element 10 may be a laminated film capacitor (for example, rectangular parallelepiped) in which metallized films are laminated.

[0033] The element body 11 has a first end face 11a and a second end face 11b facing each other in the second direction D2.

[0034] The element body 11 further has a side surface 11c extending in the second direction D2 so as to connect the peripheries of the first end surface 11a and the second end surface 11b.

[0035] From the viewpoint of reducing the height of capacitor element 10, it is preferable that element body 11 has a flat cross-sectional shape when viewed in a cross section perpendicular to the winding axis direction (second direction D2 in FIGS. 3 and 4) of element body 11. Specifically, it is preferable that element body 11 be pressed into a flattened shape such as an ellipse or oval, and that the cross-sectional shape of element body 11 be a shape that is thinner than when the cross-sectional shape of element body 11 is a perfect circle.

[0036] Whether or not the element body has been pressed to have a flat cross-sectional shape can be confirmed, for example, by checking whether or not there are press marks on the element body.

[0037] Capacitor element 10 may have a cylindrical winding shaft that is disposed on the central axis of first metallized film 13a and second metallized film 13b in a wound state and serves as the winding shaft when first metallized film 13a and second metallized film 13b are wound.

[0038] First metallized film 13a includes first dielectric film 14a and first metal layer 15a.

[0039] The first dielectric film 14a has a first main surface 14aa and a second main surface 14ab facing each other in the first direction D1.

[0040] The first metal layer 15a is provided on the first main surface 14aa of the first dielectric film 14a. Specifically, the first metal layer 15a is provided on the first main surface 14aa of the first dielectric film 14a so as to reach one side edge of the first dielectric film 14a in the second direction D2 but not to reach the other side edge of the first dielectric film 14a.

[0041] Second metallized film 13b includes second dielectric film 14b and second metal layer 15b.

[0042] The second dielectric film 14b has a first main surface 14ba and a second main surface 14bb that face each other in the first direction D1.

[0043] The second metal layer 15b is provided on the first main surface 14ba of the second dielectric film 14b. Specifically, the second metal layer 15b is provided on the first main surface 14ba of the second dielectric film 14b so as not to reach one side edge of the second dielectric film 14b in the second direction D2 but to reach the other side edge of the second dielectric film 14b.

[0044] In element body 11, adjacent first metallized films 13a and second metallized films 13b are shifted in second direction D2 so that the end of first metal layer 15a that reaches the side edge of first dielectric film 14a is exposed at first end face 11a of element body 11, and the end of second metal layer 15b that reaches the side edge of second dielectric film 14b is exposed at second end face 11b of element body 11. That is, in adjacent first metallized films 13a and second metallized films 13b, first metallized film 13a protrudes toward first external electrode 12a relative to second metallized film 13b. In addition, in adjacent first metallized films 13a and second metallized films 13b, second metallized film 13b protrudes toward second external electrode 12b relative to first metallized film 13a. In this state, the first metal layer 15a is connected to the first external electrode 12a but is not connected to the second external electrode 12b, and the second metal layer 15b is connected to the second external electrode 12b but is not connected to the first external electrode 12a.

[0045] In element body 11, adjacent first metallized films 13a and second metallized films 13b are shifted in second direction D2 as described above, so that, among adjacent first dielectric films 14a and second dielectric films 14b, first dielectric film 14a having first metal layer 15a provided on first main surface 14aa protrudes toward first external electrode 12a relative to second dielectric film 14b having no first metal layer 15a provided on its main surface. Also, among adjacent first dielectric films 14a and second dielectric films 14b, second dielectric film 14b having second metal layer 15b provided on first main surface 14ba protrudes toward second external electrode 12b relative to first dielectric film 14a having no second metal layer 15b provided on its main surface.

[0046] Since element body 11 is formed by winding first metallized film 13a and second metallized film 13b in a stacked state in first direction D1, it can be said that element body 11 includes first dielectric film 14a, first metal layer 15a, second dielectric film 14b, and second metal layer 15b in this order in first direction D1. It can also be said that element body 11 is a wound body formed by winding first dielectric film 14a, first metal layer 15a, second dielectric film 14b, and second metal layer 15b in this order in first direction D1.

[0047] In element body 11, first main surface 14aa of first dielectric film 14a and second main surface 14bb of second dielectric film 14b face each other in first direction D1, and second main surface 14ab of first dielectric film 14a and first main surface 14ba of second dielectric film 14b face each other in first direction D1. Thus, in element body 11, first metallized film 13a and second metallized film 13b are wound in a stacked state in first direction D1. In other words, in element body 11, first metallized film 13a is on the inside of second metallized film 13b, specifically, first metal layer 15a is on the inside of first dielectric film 14a, and second metal layer 15b is on the inside of second dielectric film 14b. That is, in element body 11, first metal layer 15a and second metal layer 15b face each other with first dielectric film 14a or second dielectric film 14b sandwiched therebetween.

[0048] The first metal layer 15a may be provided with a fuse portion. The fuse portion provided in the first metal layer 15a is, for example, a portion that connects a divided electrode portion formed by dividing a portion of the first metal layer 15a that faces the second metal layer 15b into multiple portions with an electrode portion that does not face the second metal layer 15b. Examples of electrode patterns of the first metal layer 15a provided with a fuse portion include the electrode patterns disclosed in JP 2004-363431 A and JP 5-251266 A.

[0049] Similar to the first metal layer 15a, the second metal layer 15b may also be provided with a fuse portion.

[0050] The first dielectric film 14a may contain a curable resin as a main component.

[0051] In this specification, the term "major component" means the component with the highest weight percentage, preferably a component with a weight percentage greater than 50% by weight.

[0052] The curable resin may be a thermosetting resin or a photocurable resin.

[0053] In this specification, thermosetting resin refers to a resin that can be cured by heat, but the curing method is not limited thereto. Therefore, thermosetting resins also include resins that can be cured by methods other than heat (e.g., light, electron beams, etc.) as long as they are resins that can be cured by heat. 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 being subjected to external heat or the like are also considered thermosetting resins. The same applies to photocurable resins; as long as they are resins that can be cured by light, they also include resins that can be cured by methods other than light (e.g., heat, etc.).

[0054] The curable resin is preferably a cured product of a first organic material having a hydroxyl group (OH group) and a second organic material having an isocyanate group (NCO group). In this case, the curable resin is a cured product having a urethane bond obtained by reacting the hydroxyl group of the first organic material with the isocyanate group of the second organic material.

[0055] The presence of urethane bonds in the dielectric film can be confirmed by analysis with a Fourier transform infrared spectrophotometer (FT-IR).

[0056] When the curable resin is obtained by the above-described reaction, uncured portions of the starting material may remain in the first dielectric film 14a. For example, the first dielectric film 14a may contain at least one of a hydroxyl group and an isocyanate group. In this case, the first dielectric film 14a may contain either a hydroxyl group or an isocyanate group, or may contain both a hydroxyl group and an isocyanate group.

[0057] The presence of hydroxyl groups and / or isocyanate groups in the dielectric film can be confirmed by FT-IR analysis.

[0058] Examples of the first organic material include phenoxy resin, polyvinyl acetoacetal resin, and polyvinyl butyral resin.

[0059] As the first organic material, a plurality of types of organic materials may be used in combination.

[0060] Examples of the second organic material include aromatic polyisocyanates such as diphenylmethane diisocyanate (MDI) and tolylene diisocyanate (TDI), and aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI). As the second organic material, at least one modified product of these polyisocyanates may be used, or a mixture of at least one modified product of these polyisocyanates may be used.

[0061] As the second organic material, a plurality of types of organic materials may be used in combination.

[0062] The first dielectric film 14a may contain a thermoplastic resin as a main component.

[0063] Examples of the thermoplastic resin include polypropylene resin, polyethersulfone resin, polyetherimide resin, and polyarylate resin.

[0064] The first dielectric film 14a may contain additives to impart various functions.

[0065] The additives include, for example, a leveling agent for imparting smoothness.

[0066] The additive preferably has a functional group that reacts with a hydroxyl group and / or an isocyanate group and forms part of the crosslinked structure of the cured product. Examples of such additives include resins having at least one functional group selected from the group consisting of a hydroxyl group, an epoxy group, a silanol group, and a carboxyl group.

[0067] Like the first dielectric film 14a, the second dielectric film 14b may contain a thermosetting resin as a main component, a photocurable resin as a main component, or a thermoplastic resin as a main component, and like the first dielectric film 14a, the second dielectric film 14b may also contain an additive.

[0068] The first dielectric film 14a and the second dielectric film 14b may have different compositions, but preferably have the same composition.

[0069] The thickness of the first dielectric film 14a and the second dielectric film 14b is preferably 1 μm or more and 10 μm or less, and more preferably 3 μm or more and 5 μm or less.

[0070] The thicknesses of the first dielectric film 14a and the second dielectric film 14b may be different from each other, but are preferably the same.

[0071] The thickness of the dielectric film is measured using an optical film thickness gauge.

[0072] The first dielectric film 14a and the second dielectric film 14b are each preferably produced by forming a resin solution containing the above-mentioned resin material into a film, and then curing it by heat treatment.

[0073] Examples of materials that can be used to form the first metal layer 15a and the second metal layer 15b include metals such as aluminum, zinc, titanium, magnesium, tin, and nickel.

[0074] The compositions of the first metal layer 15a and the second metal layer 15b may be different from each other, but are preferably the same.

[0075] The thickness of the first metal layer 15a and the second metal layer 15b is preferably 5 nm or more and 40 nm or less.

[0076] The thickness of the first metal layer 15a and the second metal layer 15b may be different from each other, but it is preferable that they are the same.

[0077] The thickness of the metal layer is measured by observing a cross section of the metallized film along the first direction using a transmission electron microscope (TEM).

[0078] The first metal layer 15a and the second metal layer 15b are preferably formed by depositing the metals described above on the major surfaces of the first dielectric film 14a and the second dielectric film 14b, respectively.

[0079] Although the above describes an embodiment in which element body 11 includes two metallized films, element body 11 may also include a single metallized film. For example, element body 11 may include a metallized film having first dielectric film 14a in which first metal layer 15a is provided on first main surface 14aa and second metal layer 15b is provided on second main surface 14ab, and second dielectric film 14b in which no metal layer is provided. Alternatively, element body 11 may include a metallized film having second dielectric film 14b in which first metal layer 15a is provided on second main surface 14bb and second metal layer 15b is provided on first main surface 14ba, and first dielectric film 14a in which no metal layer is provided.

[0080] The first external electrode 12a is provided on the surface of the element body 11. In the example shown in Figures 3 and 4, the first external electrode 12a is provided on the first end surface 11a of the element body 11. The first external electrode 12a is connected to the first metal layer 15a by contacting the end of the first metal layer 15a exposed at the first end surface 11a of the element body 11. On the other hand, the first external electrode 12a is not connected to the second metal layer 15b.

[0081] The second external electrode 12b is provided at a position separate from the first external electrode 12a on the surface of the element body 11. In the example shown in Figures 3 and 4, the second external electrode 12b is provided on the second end face 11b of the element body 11. The second external electrode 12b is connected to the second metal layer 15b by contacting the end of the second metal layer 15b exposed at the second end face 11b of the element body 11. On the other hand, the second external electrode 12b is not connected to the first metal layer 15a.

[0082] The first external electrode 12a and the second external electrode 12b have mutually different polarities. For example, the first external electrode 12a may be a positive pole (P pole) and the second external electrode 12b may be a negative pole (N pole), or the first external electrode 12a may be a negative pole (N pole) and the second external electrode 12b may be a positive pole (P pole).

[0083] Examples of materials that can be used to form the first external electrode 12a and the second external electrode 12b include metals such as zinc, aluminum, tin, and zinc-aluminum alloys.

[0084] The first external electrode 12a and the second external electrode 12b may have different compositions, but preferably have the same composition.

[0085] The first external electrode 12a and the second external electrode 12b are preferably formed by spraying the above-mentioned metal onto the first end face 11a and the second end face 11b of the element body 11, respectively.

[0086] As shown in FIG. 2, capacitor element 10 is housed inside exterior case 20.

[0087] Capacitor element 10 is preferably housed inside outer case 20 so as to be separated from the inner surface of outer case 20 .

[0088] FIG. 5 is a perspective view that schematically shows the exterior case shown in FIG.

[0089] 5, the exterior case 20 is a cylindrical shape with a bottom and an opening 21. Specifically, the exterior case 20 is a cylindrical shape with a bottom and an opening 21 at one end in the third direction D3.

[0090] In the example shown in Figure 5, the outer case 20 has a bottom 22 facing the opening 21 in the third direction D3, and side wall portions 23 (in Figure 5, it includes four side wall portions 23) extending from the bottom 22 toward the opening 21 in the third direction D3.

[0091] The exterior case 20 may be, for example, a resin case or a metal case.

[0092] When the exterior case 20 is a resin case, examples of the resin that constitutes the resin case include liquid crystal polymer (LCP), polyphenylene sulfide resin, polybutylene terephthalate resin, etc. Among these, it is preferable that the resin case contains a liquid crystal polymer.

[0093] The liquid crystal polymer contained in the resin case may be, for example, a liquid crystal polymer having p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid groups in its skeleton. Liquid crystal polymers formed as polycondensates using various components other than p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid groups, such as phenol, phthalic acid, and ethylene terephthalate, may also be used. Liquid crystal polymers are also classified into types I, II, and III, but the material refers to the same material as the liquid crystal polymer formed from the above-mentioned components.

[0094] The resin case preferably further contains an inorganic filler in addition to the liquid crystal polymer.

[0095] The inorganic filler contained in the resin case can be a material with a higher strength than the liquid crystal polymer. The inorganic filler is preferably a material with a higher melting point than the liquid crystal polymer, and more preferably a material with a melting point of 680°C or higher.

[0096] The shape of the inorganic filler is not particularly limited, and examples thereof include a shape having a longitudinal direction, such as a fibrous or plate-like shape. As the inorganic filler having such a shape, a plurality of inorganic materials may be used in combination. It is preferable that the resin case contains at least one of a fibrous inorganic material and a plate-like inorganic material as the inorganic filler.

[0097] In this specification, a filler being fibrous means that the relationship between the longitudinal dimension in the longitudinal direction and the cross-sectional diameter in a cross section perpendicular to the longitudinal direction is longitudinal dimension / cross-sectional diameter ≧5 (i.e., the aspect ratio is 5:1 or more). Here, the cross-sectional diameter is the distance between the longest two points on the periphery of the cross section. If the cross-sectional diameter varies in the longitudinal direction, the measurement is taken at the point where the cross-sectional diameter is largest.

[0098] In this specification, a filler being plate-shaped means that the relationship between the cross-sectional diameter of the surface with the largest projected area and the maximum height in the direction perpendicular to this cross section is cross-sectional diameter / maximum height ≧3.

[0099] It is preferable that at least a portion of the inorganic filler has a portion oriented in a direction from the bottom 22 side toward the opening 21 side in the side wall 23 of the outer case 20, and a portion oriented in the outer peripheral direction of the side wall 23, and is dispersed inside the outer case 20.

[0100] The inorganic filler preferably has a diameter of 5 μm or more and a length of 50 μm or more.

[0101] It is preferable that the inorganic filler be dispersed throughout the exterior case 20 without agglomerating.

[0102] Examples of inorganic fillers include inorganic materials such as fibrous glass filler, plate-like talc or mica, etc. Among these, it is preferable that the inorganic filler contains fibrous glass filler as a main component.

[0103] Even when the resin case contains another resin (for example, polyphenylene sulfide resin) instead of the liquid crystal polymer, it is preferable that the resin case further contains an inorganic filler as described above.

[0104] The resin case is manufactured by a method such as injection molding or 3D printing (three-dimensional modeling).

[0105] When the exterior case 20 is a metal case, examples of the metal constituting the metal case include simple metals such as aluminum, magnesium, iron, stainless steel, and copper, and alloys containing at least one of these simple metals. Of these, it is preferable that the metal case contains aluminum or an aluminum alloy.

[0106] The metal case is manufactured by a method such as impact molding or 3D printing (three-dimensional modeling).

[0107] 2, the first bus bar 30a is electrically connected to the first external electrode 12a. The first bus bar 30a may be connected to the first external electrode 12a by, for example, welding or via a joining member such as solder.

[0108] As shown in FIG. 2, the first bus bar 30a is drawn out to the outside of the exterior case 20.

[0109] The first bus bar 30a is electrically connected to the first external electrode 12a and is drawn out to the outside of the exterior case 20, so that the first external electrode 12a (capacitor element 10) is electrically led out to the outside of the exterior case 20 via the first bus bar 30a. The first bus bar 30a is drawn out to the outside of the exterior case 20 and connected to a connection target (not shown) such as a board or device by, for example, laser welding.

[0110] In the example shown in Figure 2, the first bus bar 30a has a first portion 31a extending in the second direction D2 and the third direction D3 inside the outer case 20, a second portion 32a extending from the first portion 31a in the first direction D1 inside the outer case 20, and a third portion 33a extending from the first portion 31a in the third direction D3 outside the outer case 20.

[0111] First portion 31a of first bus bar 30a faces the inner surface of exterior case 20 in first direction D1. Specifically, first portion 31a of first bus bar 30a faces the inner surface of side wall portion 23 (see FIG. 5) of exterior case 20 in first direction D1.

[0112] It is preferable that the first portion 31a of the first bus bar 30a faces the side surface 11c of the element body 11 in the first direction D1. Specifically, it is preferable that the first portion 31a of the first bus bar 30a overlaps, in the first direction D1, the side surface 11c of the surface of the element body 11 on which the first external electrode 12a and the second external electrode 12b are not provided. In this case, the equivalent series inductance of the capacitor module 1 is likely to decrease.

[0113] It is preferable that the first portion 31a of the first bus bar 30a is located away from a side surface 11c on which the first external electrode 12a and the second external electrode 12b are not provided, among the surfaces of the element body 11. In this case, insulation between the element body 11 and the first bus bar 30a (first portion 31a) is more easily ensured.

[0114] Second portion 32a of first bus bar 30a faces the inner surface of exterior case 20 in second direction D2. Specifically, second portion 32a of first bus bar 30a faces the inner surface of side wall portion 23 (see FIG. 5) of exterior case 20 in second direction D2.

[0115] The second portion 32a of the first bus bar 30a is preferably connected to the first external electrode 12a while facing the first end surface 11a of the element body 11 in the second direction D2.

[0116] The third portion 33a of the first bus bar 30a protrudes toward the outside of the exterior case 20. The third portion 33a of the first bus bar 30a is drawn out to the outside of the exterior case 20 and connected to a connection target (not shown) such as a board or device by, for example, laser welding.

[0117] The first bus bar 30a is preferably plate-shaped.

[0118] The first busbar 30a may have a partially bent shape. In the example shown in Fig. 2, the first busbar 30a has a shape in which the first portion 31a and the second portion 32a are connected, here, a bent L-shape, when viewed from the third direction D3. In the example shown in Fig. 2, the first busbar 30a has a shape in which the third portion 33a is bent, here, a stepped bent shape, when viewed from the second direction D2.

[0119] 2, the second bus bar 30b is electrically connected to the second external electrode 12b. The second bus bar 30b may be connected to the second external electrode 12b by, for example, welding or via a joining member such as solder.

[0120] As shown in FIG. 2, the second bus bar 30b is drawn out to the outside of the exterior case 20.

[0121] The second bus bar 30b is electrically connected to the second external electrode 12b and is drawn out to the outside of the exterior case 20, so that the second external electrode 12b (capacitor element 10) is electrically led out to the outside of the exterior case 20 via the second bus bar 30b. The second bus bar 30b is drawn out to the outside of the exterior case 20 and connected to a connection target (not shown) such as a board or device by, for example, laser welding.

[0122] In the example shown in Figure 2, the second bus bar 30b has a first portion 31b extending in the second direction D2 and the third direction D3 inside the outer case 20, a second portion 32b extending from the first portion 31b in the first direction D1 inside the outer case 20, and a third portion 33b extending from the first portion 31b in the third direction D3 outside the outer case 20.

[0123] First portion 31b of second bus bar 30b faces the inner surface of exterior case 20 in first direction D1. Specifically, first portion 31b of second bus bar 30b faces the inner surface of side wall portion 23 (see FIG. 5) of exterior case 20 in first direction D1.

[0124] It is preferable that the first portion 31b of the second busbar 30b faces the side surface 11c of the element body 11 in the first direction D1. Specifically, it is preferable that the first portion 31b of the second busbar 30b overlaps, in the first direction D1, the side surface 11c of the surface of the element body 11 on which the first external electrode 12a and the second external electrode 12b are not provided. In this case, the equivalent series inductance of the capacitor module 1 is likely to decrease.

[0125] It is preferable that the first portion 31b of the second bus bar 30b is located away from a side surface 11c on which the first external electrode 12a and the second external electrode 12b are not provided, among the surfaces of the element body 11. In this case, insulation between the element body 11 and the second bus bar 30b (first portion 31b) is more easily ensured.

[0126] Second portion 32b of second busbar 30b faces the inner surface of exterior case 20 in second direction D2. Specifically, second portion 32b of second busbar 30b faces the inner surface of side wall portion 23 (see FIG. 5) of exterior case 20 in second direction D2.

[0127] The second portion 32b of the second bus bar 30b is preferably connected to the second external electrode 12b while facing the second end face 11b of the element body 11 in the second direction D2.

[0128] The third portion 33b of the second bus bar 30b protrudes toward the outside of the exterior case 20. The third portion 33b of the second bus bar 30b is drawn out to the outside of the exterior case 20 and connected to a connection target (not shown) such as a board or device by, for example, laser welding.

[0129] The second bus bar 30b is preferably plate-shaped.

[0130] The second busbar 30b may have a partially bent shape. In the example shown in Fig. 2, the second busbar 30b has a shape in which the first portion 31b and the second portion 32b are connected, here an L-shaped bent shape, when viewed from the third direction D3. In the example shown in Fig. 2, the second busbar 30b has a shape in which the third portion 33b is bent, here a stepped bent shape, when viewed from the second direction D2.

[0131] The shapes of the first bus bar 30a and the second bus bar 30b may be symmetrical (for example, line symmetrical) or asymmetrical.

[0132] The first bus bar 30a and the second bus bar 30b are electrically connected to external electrodes having different polarities, and therefore have different polarities. For example, if the first external electrode 12a is a positive electrode and the second external electrode 12b is a negative electrode, the first bus bar 30a is a bus bar for the positive electrode, and the second bus bar 30b is a bus bar for the negative electrode. Alternatively, if the first external electrode 12a is a negative electrode and the second external electrode 12b is a positive electrode, the first bus bar 30a is a bus bar for the negative electrode, and the second bus bar 30b is a bus bar for the positive electrode.

[0133] Examples of materials that can be used to form the first bus bar 30a and the second bus bar 30b include metals such as copper, oxygen-free copper, aluminum, and alloys containing at least one of these. Among these, copper or oxygen-free copper is preferred as the material for the first bus bar 30a and the second bus bar 30b. When the first bus bar 30a and the second bus bar 30b are made of a copper-based material, examples of materials that can be used include oxygen-free copper (copper: 99.96% by weight or more), tough pitch copper (copper: 99.90% by weight or more), and phosphorus-deoxidized copper (copper: 99.90% by weight or more, phosphorus: 0.015% by weight or more, 0.040% by weight or less).

[0134] The constituent materials of the first bus bar 30a and the second bus bar 30b may be the same as or different from each other.

[0135] The thickness of the first bus bar 30a and the second bus bar 30b may be the same as or different from each other.

[0136] 2, the insulator 40 covers a portion of each of the first bus bar 30a and the second bus bar 30b, thereby ensuring a creepage distance between the first bus bar 30a and the second bus bar 30b, and therefore ensuring insulation between the first bus bar 30a and the second bus bar 30b.

[0137] 2, the insulator 40 covers both main surfaces of the first portion 31a of the first bus bar 30a and both main surfaces of the first portion 31b of the second bus bar 30b. Specifically, the insulator 40 covers both main surfaces of the first portion 31a of the first bus bar 30a, excluding the second portion 32a connected to the first external electrode 12a inside the exterior case 20 and the third portion 33a protruding toward the outside of the exterior case 20. The insulator 40 also covers both main surfaces of the first portion 31b of the second bus bar 30b, excluding the second portion 32b connected to the second external electrode 12b inside the exterior case 20 and the third portion 33b protruding toward the outside of the exterior case 20.

[0138] The insulator 40 may cover either the entirety or a part of both main surfaces of the first portion 31a of the first bus bar 30a.

[0139] For example, holes 41 may be provided in at least one of a portion of insulator 40 covering one main surface of first portion 31a of first busbar 30a and a portion covering the other main surface of first portion 31a of first busbar 30a so that first portion 31a of first busbar 30a is exposed. In other words, insulator 40 may cover both main surfaces of first portion 31a of first busbar 30a except for the portions exposed through holes 41.

[0140] The insulator 40 may cover either the entirety or a part of both main surfaces of the first portion 31b of the second bus bar 30b.

[0141] For example, holes 41 may be provided in at least one of a portion of insulator 40 covering one main surface of first portion 31b of second busbar 30b and a portion covering the other main surface of first portion 31b of second busbar 30b, so that first portion 31b of second busbar 30b is exposed. In other words, insulator 40 may cover both main surfaces of first portion 31b of second busbar 30b except for the portions exposed through holes 41.

[0142] The shape of the holes 41 in the insulator 40 is not particularly limited.

[0143] There is no particular limitation on the number of holes 41 in the insulator 40. The number of holes 41 in the insulator 40 may be one or more.

[0144] The insulator 40 does not necessarily have to have the holes 41 formed therein.

[0145] The insulator 40 may be made of, for example, resin.

[0146] The resin that constitutes the insulator 40 may be, for example, polyphenylene sulfide (PPS) resin.

[0147] FIG. 6 is a perspective view that schematically illustrates the first bus bar, the second bus bar, and the insulators shown in FIG.

[0148] In the capacitor module 1, as shown in Fig. 6, the insulator 40 is molded integrally with the first bus bar 30a and the second bus bar 30b. In the example shown in Fig. 6, the insulator 40 is molded integrally with the first bus bar 30a and the second bus bar 30b, thereby forming an integrally molded product 50. In other words, the first bus bar 30a, the second bus bar 30b, and the insulator 40 form the integrally molded product 50.

[0149] In the integrally molded product 50, the insulator 40 covers the first bus bar 30a and the second bus bar 30b so that a portion of each of the first bus bar 30a and the second bus bar 30b is exposed, in this case, the second portion 32a and the third portion 33a of the first bus bar 30a are exposed, and further, the second portion 32b and the third portion 33b of the second bus bar 30b are exposed.

[0150] In the capacitor module 1, the insulator 40 is molded integrally with the first bus bar 30a and the second bus bar 30b by insert molding. That is, the first bus bar 30a, the second bus bar 30b, and the insulator 40 constitute an insert-molded product as an integrally molded product 50. In this case, the first bus bar 30a and the second bus bar 30b are placed in a mold as insert parts, and the insulator 40 is filled around specific portions of the first bus bar 30a and the second bus bar 30b, so that the insulator 40 is molded integrally with the first bus bar 30a and the second bus bar 30b.

[0151] In the capacitor module 1, the insulator 40 is molded integrally with the first bus bar 30a and the second bus bar 30b, so that the first bus bar 30a and the second bus bar 30b are fixed to the insulator 40 with high positional accuracy. In other words, in the capacitor module 1, the insulator 40 is molded integrally with the first bus bar 30a and the second bus bar 30b, so that the first bus bar 30a and the second bus bar 30b are positioned relative to the insulator 40 with high positional accuracy. In the capacitor module 1, the positional accuracy of the first bus bar 30a and the second bus bar 30b positioned relative to the insulator 40 is mainly controlled by the mold used when molding the insulator 40 integrally with the first bus bar 30a and the second bus bar 30b by, for example, insert molding. Therefore, the capacitor module 1 is less susceptible to influences such as variations in size of the first bus bar 30a and the second bus bar 30b when manufacturing the first bus bar 30a and the second bus bar 30b, or distortion of the first bus bar 30a and the second bus bar 30b when individually connecting the first bus bar 30a and the second bus bar 30b to the first external electrode 12a and the second external electrode 12b of the capacitor element 10. Therefore, in the capacitor module 1, even if the sizes of the first busbars 30a and the second busbars 30b vary when the first busbars 30a and the second busbars 30b are manufactured, or even if the first busbars 30a and the second busbars 30b are distorted when the first busbars 30a and the second busbars 30b are individually connected to the first external electrodes 12a and the second external electrodes 12b of the capacitor element 10, the insulators 40 are molded integrally with the first busbars 30a and the second busbars 30b, so that the first busbars 30a and the second busbars 30b can be positioned with high positional accuracy relative to the insulators 40. For these reasons, in the capacitor module 1, it is possible to improve the positional accuracy of the first busbars 30a and the second busbars 30b relative to connection targets such as boards and devices.

[0152] As described above, the capacitor module 1 is capable of increasing the positional accuracy of the first bus bar 30a and the second bus bar 30b relative to the connection object, such as a substrate or device. Therefore, it can easily accommodate cases where high positional accuracy of the first bus bar 30a and the second bus bar 30b relative to the connection object is required, such as when laser welding the first bus bar 30a and the second bus bar 30b to the connection object.

[0153] In conventional capacitor modules, the busbars are sometimes positioned using ribs that protrude from the inner surface of the exterior case. However, considering that the size of the busbars varies when they are manufactured and that the busbars may be distorted when they are connected to the external electrodes of the capacitor elements, positioning the busbars by molding an insulator integrally with the busbars, as in the capacitor module of the present invention, allows for higher positioning accuracy than positioning the busbars using ribs that protrude from the inner surface of the exterior case, and ultimately improves the positioning accuracy of the busbars relative to their connection targets, such as boards and devices.

[0154] In the capacitor module 1, the insulator 40 is integrally molded with the first bus bar 30a and the second bus bar 30b, so that the first bus bar 30a and the second bus bar 30b are positioned relative to the insulator 40. In addition, the first bus bar 30a and the second bus bar 30b may be positioned by ribs protruding from the inner surface of the outer case 20.

[0155] Furthermore, in the capacitor module 1, the insulator 40 is molded integrally with the first bus bar 30a and the second bus bar 30b, and therefore the insulator 40 is interposed between the first bus bar 30a and the second bus bar 30b. When manufacturing the capacitor module 1, for example, if the insulator 40 is molded integrally with the first bus bar 30a and the second bus bar 30b by insert molding, the insulator 40 is filled around specific portions of the first bus bar 30a and the second bus bar 30b with the first bus bar 30a and the second bus bar 30b placed in a mold, thereby interposing the insulator 40 between the first bus bar 30a and the second bus bar 30b. Thus, when manufacturing the capacitor module 1, the insulator 40 can be interposed between the first bus bar 30a and the second bus bar 30b simply by molding the insulator 40 integrally with the first bus bar 30a and the second bus bar 30b. For example, unlike the capacitor described in Patent Document 2, it is not necessary to insert an insulating paper, insulating plate, or the like that is separate (independent) from the first bus bar 30a and the second bus bar 30b between the first bus bar 30a and the second bus bar 30b. Therefore, when manufacturing the capacitor module 1, by molding the insulator 40 integrally with the first bus bar 30a and the second bus bar 30b, it is easy to interpose the insulator 40 between the first bus bar 30a and the second bus bar 30b even if the distance between the first bus bar 30a and the second bus bar 30b is reduced. For these reasons, the capacitor module 1 allows the distance between the first bus bar 30a and the second bus bar 30b to be reduced. When manufacturing the capacitor module 1, for example, when the insulator 40 is molded integrally with the first bus bar 30a and the second bus bar 30b by insert molding, the distance between the first bus bar 30a and the second bus bar 30b can be controlled by placing the first bus bar 30a and the second bus bar 30b at desired positions in the mold.

[0156] As described above, in the capacitor module 1, it is possible to reduce the distance between the first bus bar 30a and the second bus bar 30b, which makes it easier for the electromagnetic fields generated by the first bus bar 30a and the second bus bar 30b to cancel each other out, and as a result, it is possible to reduce the equivalent series inductance of the capacitor module 1.

[0157] In the capacitor busbar structure described in Patent Document 1, the insulator is integrated with only the opposing plate portion of one of the pair of busbars by insert molding, but not with the opposing plate portion of the other of the pair of busbars by insert molding. This is because, in the capacitor busbar structure described in Patent Document 1, the opposing surface of the opposing plate portion of the other of the pair of busbars that faces the opposing plate portion of the one busbar abuts against the back surface of the insulator, which makes it easy to check for voids or defects in the filled resin that could cause insulation defects during element assembly before the abutment. Therefore, in the capacitor busbar structure described in Patent Document 1, integrating the insulator with the opposing plate portions of both of the pair of busbars by insert molding would be contrary to the spirit of Patent Document 1. On the other hand, in the capacitor described in Patent Document 2, as shown in Figure 2 of Patent Document 2, the fixing portion B2 of the insulating member fixes both the first terminal T1 and the second terminal T2, but as mentioned above, this goes against the spirit of Patent Document 1. Therefore, it is unlikely that anyone would think of combining the busbar structure of the capacitor described in Patent Document 1 with the capacitor described in Patent Document 2 to achieve a configuration in which the insulator fixes both of the pair of bus bars, that is, a configuration in which the insulator is integrated with the opposing plate portions of both of the pair of bus bars by insert molding. Therefore, the capacitor module of the present invention, for example, capacitor module 1, cannot be conceived from the busbar structure of the capacitor described in Patent Document 1 or from a combination of the busbar structure of the capacitor described in Patent Document 1 and the capacitor described in Patent Document 2.

[0158] The fact that the insulator 40 is molded integrally with the first bus bar 30a and the second bus bar 30b by insert molding can be confirmed by (1) the presence of traces on the insulator 40 of the inlet for the resin that constitutes the insulator 40 during insert molding, and (2) the absence of interfaces on the insulator 40 that would indicate that multiple components are bonded together.

[0159] In the capacitor module 1, the exterior case 20 and the insulator 40 are preferably fitted together.

[0160] In the capacitor module 1, the exterior case 20 and the insulator 40 are fitted together, so that an integrally molded product 50 formed by molding the insulator 40 integrally with the first bus bar 30a and the second bus bar 30b is fixed to the exterior case 20. As described above, in the capacitor module 1, the first bus bar 30a and the second bus bar 30b are positioned on the insulator 40 with high positional accuracy in the integrally molded product 50. Therefore, when the integrally molded product 50 is fixed to the exterior case 20, the positional accuracy of the first bus bar 30a and the second bus bar 30b relative to the connection object such as a board or device is less likely to decrease.

[0161] Furthermore, when the integrally molded item 50 is fixed to the exterior case 20, the integrally molded item 50 is less likely to come off from the exterior case 20 even when subjected to vibrations, shocks, etc. This makes it easy to accommodate cases where, for example, the capacitor module 1 is used in an automobile and is prone to vibrations, shocks, etc., and where the integrally molded item 50 is required to be firmly fixed.

[0162] Furthermore, when manufacturing the capacitor module 1 in which the outer case 20 and the insulator 40 are fitted together, for example, the first bus bar 30a and the second bus bar 30b can be individually connected to the first external electrode 12a and the second external electrode 12b of the capacitor element 10, thereby fixing the integrally molded product 50 to the capacitor element 10, and then fitting the integrally molded product 50 into the outer case 20, making it easier to manufacture the capacitor module 1.

[0163] An example of how the outer case 20 and the insulator 40 are fitted together will be described below.

[0164] 6, the insulator 40 has a planar portion 42 that extends in a planar shape. Specifically, the insulator 40 has the planar portion 42 that extends in the second direction D2 and the third direction D3.

[0165] 6, the planar portion 42 of the insulator 40 has a first main surface 42a and a second main surface 42b that face each other as part of the outer surface of the insulator 40. Specifically, the planar portion 42 of the insulator 40 has a first main surface 42a and a second main surface 42b that face each other in the first direction D1 as part of the outer surface of the insulator 40.

[0166] FIG. 7 is an enlarged perspective view schematically illustrating the capacitor module shown in FIG. 2 as viewed from one side in the first direction.

[0167] In the example shown in FIG. 7, the first main surface 42 a of the planar portion 42 of the insulator 40 is in contact with the inner surface of the exterior case 20 .

[0168] 7, one of the inner surface of the exterior case 20 and the outer surface of the insulator 40 has a recess 61a, and the other has a protrusion 62a. Here, three recesses 61a are provided on the inner surface of the exterior case 20 that contacts the first main surface 42a of the planar portion 42 of the insulator 40, and three protrusions 62a are provided on the first main surface 42a of the planar portion 42 of the insulator 40. The three recesses 61a and the three protrusions 62a are individually fitted together (one-to-one).

[0169] 7, of the recessed portion 61a and the protruding portion 62a to be fitted together, the recessed portion 61a is provided on the inner surface of the exterior case 20 that contacts the first main surface 42a of the planar portion 42 of the insulator 40, and the protruding portion 62a is provided on the first main surface 42a of the planar portion 42 of the insulator 40, but the opposite configuration is also possible. In other words, of the recessed portion 61a and the protruding portion 62a to be fitted together, the recessed portion 61a may be provided on the first main surface 42a of the planar portion 42 of the insulator 40, and the protruding portion 62a may be provided on the inner surface of the exterior case 20 that contacts the first main surface 42a of the planar portion 42 of the insulator 40.

[0170] The shapes of the recessed portion 61a and the protruding portion 62a are not particularly limited as long as they are shapes that allow the two to fit together. The recessed portion 61a and the protruding portion 62a may be, for example, linear or non-linear (for example, dot-like). If the recessed portion 61a and the protruding portion 62a are linear, the recessed portion 61a and the protruding portion 62a may be, for example, linear or curved. If the recessed portion 61a and the protruding portion 62a are non-linear, the recessed portion 61a and the protruding portion 62a may be, for example, prismatic or cylindrical.

[0171] The positions of the recess 61a and the protrusion 62a are not particularly limited as long as they are positions where they can fit together. The recess 61a (or the protrusion 62a) may be located, for example, on the periphery of the inner surface of the exterior case 20 that contacts the first main surface 42a of the planar portion 42 of the insulator 40, or may be located inside the periphery, or may be located on both sides. The protrusion 62a (or the recess 61a) may be located, for example, on the periphery of the first main surface 42a of the planar portion 42 of the insulator 40, or may be located inside the periphery, or may be located on both sides.

[0172] The number of recesses 61a and protrusions 62a is not particularly limited. The number of recesses 61a and protrusions 62a may be one each, or the same number may be multiple. When the number of recesses 61a and protrusions 62a is multiple, the number is not limited to three each as shown in FIG. 7.

[0173] When there are a plurality of recesses 61a, the sizes of the recesses 61a (for example, the sizes of the recesses 61a when viewed from the first direction D1) may be the same as each other or may be different from each other.

[0174] When there are a plurality of recesses 61a, the arrangement of the recesses 61a is not particularly limited. The recesses 61a may be arranged regularly or irregularly.

[0175] When there are multiple convex portions 62a, the sizes of the multiple convex portions 62a, for example, the sizes of the multiple convex portions 62a when viewed from the first direction D1, may be the same as each other or may be different from each other.

[0176] When there are a plurality of protrusions 62a, the arrangement of the protrusions 62a is not particularly limited. The protrusions 62a may be arranged regularly or irregularly.

[0177] In the example shown in Figure 7, the first main surface 42a of the planar portion 42 of the insulator 40 is fitted into and in contact with the inner surface of the outer case 20, but the first main surface 42a of the planar portion 42 of the insulator 40 may simply be in contact with the inner surface of the outer case 20 without being fitted into the inner surface.

[0178] 6, the insulator 40 further includes a columnar portion 43 extending in a columnar shape from the second main surface 42b of the planar portion 42. Specifically, the insulator 40 further includes a columnar portion 43 extending in the first direction D1 from the second main surface 42b of the planar portion 42.

[0179] The extending direction of the columnar portion 43 of the insulator 40 is not limited to the first direction D1, and may be a direction inclined with respect to the first direction D1. For example, the columnar portion 43 of the insulator 40 may extend in a direction perpendicular to the second main surface 42b of the planar portion 42, or may extend in a non-perpendicular oblique direction.

[0180] There are no particular limitations on the position of the columnar portion 43 on the second main surface 42b of the planar portion 42 of the insulator 40. The columnar portion 43 of the insulator 40 may extend from the peripheral edge of the second main surface 42b of the planar portion 42, from a position more inward than the peripheral edge, or from both.

[0181] There is no particular limitation on the number of columnar portions 43 of the insulator 40. The number of columnar portions 43 of the insulator 40 may be one or more.

[0182] 6, the columnar portion 43 of the insulator 40 has an end face 43a located on the opposite side to the planar portion 42 as part of the outer surface of the insulator 40. Specifically, the columnar portion 43 of the insulator 40 has an end face 43a located on the opposite side to the planar portion 42 in the first direction D1 as part of the outer surface of the insulator 40.

[0183] FIG. 8 is an enlarged perspective view schematically illustrating the capacitor module shown in FIG. 2 as viewed from the other side in the first direction.

[0184] In the example shown in FIG. 8, the end face 43 a of the columnar portion 43 of the insulator 40 is in contact with the inner surface of the exterior case 20 .

[0185] 8, a recess 61b is provided on one of the inner surface of the exterior case 20 and the outer surface of the insulator 40, and a protrusion 62b is provided on the other. Here, two recesses 61b are provided on the inner surface of the exterior case 20 that contacts the end surface 43a of the columnar portion 43 of the insulator 40, and two protrusions 62b are provided on the end surface 43a of the columnar portion 43 of the insulator 40. The two recesses 61b and the two protrusions 62b are individually fitted together (one-to-one).

[0186] 8, of the recessed portion 61b and the protruding portion 62b to be fitted together, the recessed portion 61b is provided on the inner surface of the exterior case 20 that contacts the end surface 43a of the columnar portion 43 of the insulator 40, and the protruding portion 62b is provided on the end surface 43a of the columnar portion 43 of the insulator 40, but the opposite configuration is also possible. In other words, of the recessed portion 61b and the protruding portion 62b to be fitted together, the recessed portion 61b may be provided on the end surface 43a of the columnar portion 43 of the insulator 40, and the protruding portion 62b may be provided on the inner surface of the exterior case 20 that contacts the end surface 43a of the columnar portion 43 of the insulator 40.

[0187] The shapes of the recessed portion 61b and the protruding portion 62b are not particularly limited as long as they are shapes that allow the two to fit together. The recessed portion 61b and the protruding portion 62b may be, for example, linear or non-linear (for example, dot-like). When the recessed portion 61b and the protruding portion 62b are linear, the recessed portion 61b and the protruding portion 62b may be, for example, linear or curved. When the recessed portion 61b and the protruding portion 62b are non-linear, the recessed portion 61b and the protruding portion 62b may be, for example, prismatic or cylindrical.

[0188] The positions of the recess 61b and the protrusion 62b are not particularly limited as long as they are positions where they can be fitted together. The recess 61b (or the protrusion 62b) may be located, for example, on the periphery of the inner surface of the exterior case 20 that contacts the end surface 43a of the columnar portion 43 of the insulator 40, or may be located inside the periphery, or may be located on both sides. The protrusion 62b (or the recess 61b) may be located, for example, on the periphery of the end surface 43a of the columnar portion 43 of the insulator 40, or may be located inside the periphery, or may be located on both sides.

[0189] The number of recesses 61b and protrusions 62b is not particularly limited. The number of recesses 61b and protrusions 62b may be one each, or the same number may be multiple. When the number of recesses 61b and protrusions 62b is multiple, the number is not limited to two each as shown in FIG. 8.

[0190] When there are a plurality of recesses 61b, the sizes of the recesses 61b (for example, the sizes of the recesses 61b when viewed from the first direction D1) may be the same as or different from each other.

[0191] When there are a plurality of recesses 61b, the arrangement of the recesses 61b is not particularly limited. The recesses 61b may be arranged regularly or irregularly.

[0192] When there are a plurality of convex portions 62b, the sizes of the plurality of convex portions 62b, for example, the sizes of the plurality of convex portions 62b when viewed from the first direction D1, may be the same as each other or may be different from each other.

[0193] When there are a plurality of protrusions 62b, the arrangement of the protrusions 62b is not particularly limited. The protrusions 62b may be arranged regularly or irregularly.

[0194] In the example shown in Figure 8, the end face 43a of the columnar portion 43 of the insulator 40 is fitted into the inner surface of the outer case 20 while contacting the inner surface, but the end face 43a of the columnar portion 43 of the insulator 40 may simply be in contact with the inner surface of the outer case 20 without being fitted into the inner surface.

[0195] In the example shown in Figures 7 and 8, both the first main surface 42a of the planar portion 42 of the insulator 40 and the end face 43a of the columnar portion 43 of the insulator 40 are fitted into and in contact with the inner surface of the outer case 20, but one of them may be fitted into and in contact with the inner surface of the outer case 20.

[0196] In the example shown in Figures 7 and 8, the outer case 20 and the insulator 40 are fitted together at multiple locations (here, a total of five locations), but the outer case 20 and the insulator 40 may also be fitted together at one location.

[0197] 7 and 8, the inner surface of the outer case 20 and the outer surface of the insulator 40 are fitted together, but there are no particular limitations on the positions of the fitting targets on the outer case 20 and the insulator 40. In other words, any position on the outer case 20 or the insulator 40 may be the fitting target.

[0198] The outer case 20 and the insulator 40 do not have to be fitted together.

[0199] In the capacitor module 1, it is preferable that the shortest distance G between the first bus bar 30a and the second bus bar 30b is 5 mm or less, as shown in Fig. 6. In the example shown in Fig. 6, the shortest distance G between the first bus bar 30a and the second bus bar 30b is defined as the distance in the second direction D2.

[0200] As described above, in the capacitor module 1, the distance between the first bus bar 30a and the second bus bar 30b can be reduced, and therefore the shortest distance G between the first bus bar 30a and the second bus bar 30b can be set to 5 mm or less. This makes it easier for the equivalent series inductance of the capacitor module 1 to decrease.

[0201] From the viewpoint of reducing the equivalent series inductance of the capacitor module 1, the shortest distance G between the first bus bar 30a and the second bus bar 30b is more preferably 2 mm or less, and further preferably 1 mm or less.

[0202] From the viewpoint of ensuring insulation between the first bus bar 30a and the second bus bar 30b, the shortest distance G between the first bus bar 30a and the second bus bar 30b is preferably 1 mm or more. In this case, the resin constituting the insulator 40 can be sufficiently introduced between the first bus bar 30a and the second bus bar 30b during insert molding, thereby reliably ensuring insulation between the first bus bar 30a and the second bus bar 30b.

[0203] The following describes the results of a simulation evaluation of the frequency characteristics of the equivalent series inductance of the capacitor module 1, using the capacitor module 1 shown in FIG. 1 and other figures as a simulation model, while changing the shortest distance G between the first bus bar 30a and the second bus bar 30b. The simulation evaluation was performed using Ansys Q3D Extractor (registered trademark), which is available in Ansys Electronics, an integrated electromagnetic field analysis solution from Ansys, Inc. The simulation evaluation of the equivalent series inductance of the capacitor module 1 was performed using electromagnetic field analysis in a frequency range of around 1 MHz.

[0204] FIG. 9 is a graph showing the results of a simulation evaluation of the frequency characteristics of the equivalent series inductance of the capacitor module shown in FIG. 1 etc. while changing the shortest distance between the first bus bar and the second bus bar.

[0205] 9, it was confirmed that a decrease in the shortest distance G between the first bus bar 30a and the second bus bar 30b reduces the equivalent series inductance of the capacitor module 1. It was also confirmed that, from the perspective of lowering the equivalent series inductance of the capacitor module 1, the shortest distance G between the first bus bar 30a and the second bus bar 30b is preferably 5 mm or less, more preferably 2 mm or less, and even more preferably 1 mm or less.

[0206] It is preferable that capacitor module 1 further includes a filling resin 70 filled inside exterior case 20 so as to embed capacitor element 10. In this case, capacitor element 10 is more easily held inside exterior case 20 by filling resin 70.

[0207] When capacitor element 10 is housed inside outer case 20 so as to be spaced apart from the inner surface of outer case 20, filled resin 70 is preferably filled between capacitor element 10 and outer case 20, specifically, between the outer surface of capacitor element 10 and the inner surface of outer case 20. Furthermore, filled resin 70 is preferably filled inside outer case 20 not only between capacitor element 10 and outer case 20, but also in the region from opening 21 of outer case 20 to capacitor element 10.

[0208] From the viewpoint of suppressing the penetration of moisture into capacitor element 10, it is preferable that the thickness of filling resin 70 at opening 21 of exterior case 20 is large. The thickness of filling resin 70 at opening 21 of exterior case 20 is preferably sufficiently large within the allowable range for the overall volume (physical size) of capacitor element 10 and exterior case 20, and specifically, is preferably 2 mm or more, and more preferably 4 mm or more. In particular, it is preferable that, inside exterior case 20, capacitor element 10 is positioned closer to bottom 22 than to opening 21, so that the thickness of filling resin 70 relative to capacitor element 10 is greater on the opening 21 side than on the bottom 22 side.

[0209] The thickness of the filled resin 70 is measured, for example, using a soft X-ray device if it is in a non-destructive state, and using a length measuring device such as a caliper if it is in a destructive state.

[0210] The relationship between the height of the outer case 20 and the height of the filling resin 70 in the third direction D3 is such that the thickness of the filling resin 70 at the opening 21 of the outer case 20 is as large as possible, and it may be up to a position inside the outer case 20, or it may be just about to the top, or it may overflow slightly due to surface tension.

[0211] From the viewpoint of suppressing the penetration of moisture into capacitor element 10, it is preferable to appropriately select a resin with low moisture permeability as filling resin 70, such as epoxy resin, silicone resin, urethane resin, etc. Examples of the curing agent for epoxy resin include amine curing agents, imidazole curing agents, etc.

[0212] The above-mentioned resin alone may be used as the filling resin 70, but to improve strength, a resin to which a reinforcing agent is added may also be used. Examples of the reinforcing agent include silica and alumina.

[0213] When manufacturing capacitor module 1 having filled resin 70, for example, after fitting integrally molded item 50 into exterior case 20 as described above, filling resin 70 is filled inside exterior case 20. In this case, even if pressure is applied to integrally molded item 50 from filling resin 70 when filling the interior of exterior case 20 with filling resin 70, the position of integrally molded item 50 is unlikely to change because it is fitted into exterior case 20. As a result, even in capacitor module 1 having filled resin 70, the positional accuracy of first bus bar 30a and second bus bar 30b relative to a connection target such as a board or device is unlikely to decrease.

[0214] The capacitor module 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 configuration of the capacitor module, manufacturing conditions, etc.

[0215] In the capacitor module of the present invention, the number of capacitor elements housed inside one exterior case is not particularly limited. In the capacitor module of the present invention, one exterior case may house one capacitor element or multiple capacitor elements.

[0216] In the capacitor module of the present invention, when a plurality of capacitor elements are housed inside a single exterior case, the plurality of capacitor elements may be arranged in a single row or in multiple rows. In the capacitor module of the present invention, when a plurality of capacitor elements are arranged in multiple rows, the plurality of capacitor elements may be arranged in multiple rows in one direction or in multiple directions.

[0217] In the capacitor module of the present invention, when multiple capacitor elements are housed inside a single outer case, the configurations of the multiple capacitor elements may be the same as each other, may be different from each other, or may be partially different.

[0218] The capacitor module of the present invention is useful for in-vehicle applications, such as inverters, chargers, and DC-DC converters mounted on electric vehicles.

[0219] The capacitor module of the present invention is applicable not only to in-vehicle applications but also to various fields such as power electronics. [Example]

[0220] The following describes examples that more specifically disclose the capacitor module of the present invention, but the present invention is not limited to the following examples.

[0221] As a capacitor module of the example, a capacitor module 1 shown in FIG. 1 etc. was manufactured. In this case, the insulator 40 was molded integrally with the first bus bar 30a and the second bus bar 30b by insert molding. The shortest distance G between the first bus bar 30a and the second bus bar 30b was set to 1 mm. Polyphenylene sulfide resin was used as the insulator 40.

[0222] Five capacitor modules of the example were manufactured under the above conditions. These capacitor modules are hereinafter referred to as Sample 1, Sample 2, Sample 3, Sample 4, and Sample 5.

[0223] Next, the equivalent series inductance at 1 MHz was measured for Samples 1 to 5 using a Keysight E4980A Precision LCR Meter. The measurement results are shown in Table 1.

[0224] Table 1 also shows the results of a simulation evaluation of the equivalent series inductance at around 1 MHz using the capacitor module 1 shown in Figure 1 etc. as a simulation model and electromagnetic field analysis using the above-mentioned Ansys Q3D Extractor (registered trademark) manufactured by Ansys.

[0225] [Table 1]

[0226] As shown in Table 1, the equivalent series inductance of Samples 1 to 5 was all lower than the equivalent series inductance of the simulation model. Thus, it was confirmed that the capacitor module of the present invention is more effective in lowering the equivalent series inductance than expected (simulation).

[0227] Furthermore, for samples 1 to 5, the first bus bar and the second bus bar could be laser welded to the connection object such as a substrate or device without adjusting their positions. Thus, it was confirmed that the capacitor module of the present invention is effective in increasing the positional accuracy of the first bus bar and the second bus bar relative to the connection object such as a substrate or device.

[0228] The present specification discloses the following:

[0229] <1> a capacitor element having a first external electrode and a second external electrode; an outer case in which the capacitor element is housed; a first bus bar electrically connected to the first external electrode and drawn out to the outside of the exterior case; a second bus bar electrically connected to the second external electrode and drawn out to the outside of the exterior case; an insulator covering a portion of each of the first bus bar and the second bus bar, a capacitor module, wherein the insulator is integrally formed with the first bus bar and the second bus bar;

[0230] <2> the outer case and the insulator are fitted together; <1> The capacitor module according to claim 1.

[0231] <3> a recess is provided on one of the inner surface of the outer case and the outer surface of the insulator, and a protrusion is provided on the other, The recess and the protrusion are fitted together. <2> The capacitor module according to claim 1.

[0232] <4> the insulator has a planar portion extending in a planar shape, the planar portion of the insulator has a first main surface and a second main surface facing each other, the first main surface of the planar portion of the insulator is in contact with the inner surface of the exterior case; <1> ~ <3> 10. The capacitor module according to claim 9, wherein the capacitor module is a capacitor module having a capacitance of 100.degree.

[0233] <5> the insulator further includes a columnar portion extending in a columnar shape from the second main surface of the planar portion, the columnar portion of the insulator has an end surface located opposite to the planar portion, the end face of the columnar portion of the insulator is in contact with the inner surface of the exterior case; <4> The capacitor module according to claim 1.

[0234] <6> the shortest distance between the first bus bar and the second bus bar is 5 mm or less; <1> ~ <5> 10. The capacitor module according to claim 9, wherein the capacitor module is a capacitor module having a capacitance of 100.degree.

[0235] <7> The capacitor element may further include a filling resin filled inside the exterior case so as to embed the capacitor element. <1> ~ <6> 10. The capacitor module according to claim 9, wherein the capacitor module is a capacitor module having a capacitance of 100.degree.

[0236] <8> The capacitor element is a film capacitor. <1> ~ <7> 10. The capacitor module according to claim 9, wherein the capacitor module is a capacitor module having a capacitance of 100.degree. [Explanation of symbols]

[0237] 1 Capacitor Module 10 Capacitor element 11 Base 11a: first end surface of element body 11b: second end surface of element body 11c Side of the body 12a 1st external electrode 12b 2nd external electrode 13a First metallized film 13b Second metallized film 14a First dielectric film 14aa: First main surface of first dielectric film 14ab: second main surface of first dielectric film 14b Second dielectric film 14ba: First main surface of second dielectric film 14bb: second main surface of second dielectric film 15a 1st metal layer 15b 2nd metal layer 20 outer case 21 Opening of outer case 22 Bottom of the outer case 23 Side wall of outer case 30a 1st bus bar 30b Second bus bar 31a First portion of first bus bar 31b First portion of second bus bar 32a Second part of first busbar 32b Second portion of second bus bar 33a Third portion of first busbar 33b Third portion of second bus bar 40 Insulator 41 Hole in insulator 42 Insulator surface portion 42a: First main surface of the planar portion of the insulator 42b: second main surface of the planar portion of the insulator 43 Insulator column 43a End face of the columnar part of the insulator 50 Integral molding 61a, 61b recessed portion 62a, 62b convex parts 70 Filled Resin D1 1st direction D2 2nd direction D3 Third direction G Shortest distance between the first busbar and the second busbar

Claims

1. a capacitor element having a first external electrode and a second external electrode; an outer case in which the capacitor element is housed; a first bus bar electrically connected to the first external electrode and extending to the outside of the exterior case; a second bus bar electrically connected to the second external electrode and extending to the outside of the exterior case; an insulator covering a portion of each of the first bus bar and the second bus bar, The capacitor module, wherein the insulator is integrally molded with the first bus bar and the second bus bar.

2. The capacitor module according to claim 1 , wherein the outer case and the insulator are fitted together.

3. a recess is provided on one of the inner surface of the exterior case and the outer surface of the insulator, and a protrusion is provided on the other, The capacitor module according to claim 2 , wherein the recessed portion and the protruding portion are fitted together.

4. the insulator has a planar portion extending in a planar shape, the planar portion of the insulator has a first main surface and a second main surface facing each other, 4. The capacitor module according to claim 1, wherein the first main surface of the planar portion of the insulator is in contact with an inner surface of the exterior case.

5. the insulator further includes a columnar portion extending in a columnar shape from the second main surface of the planar portion, the columnar portion of the insulator has an end surface located opposite to the planar portion, The capacitor module according to claim 4 , wherein the end faces of the columnar portions of the insulator are in contact with the inner surface of the exterior case.

6. 4. The capacitor module according to claim 1, wherein the shortest distance between the first bus bar and the second bus bar is 5 mm or less.

7. 4. The capacitor module according to claim 1, further comprising a filling resin filled inside the exterior case so as to embed the capacitor element.

8. The capacitor module according to any one of claims 1 to 3, wherein the capacitor element is a film capacitor.

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