Capacitor module

Abstract

To provide a capacitor module which efficiently cools a bus bar and a capacitor element via the bus bar.SOLUTION: Capacitor module 1 includes at least one capacitor element 10, first bus bar 20 electrically connected to the capacitor element and having a terminal on a side opposite to capacitor element 10, case 40 in which capacitor element 10 is housed, and filler resin 50 filling the inside of case 40 such that capacitor element 10 is embedded in filler resin 50. First bus bar 20 includes first part 22 connected to capacitor elements 10 and embedded in filler synthetic resin 50, second part 23 protruding away from capacitor elements 10, and first terminals 21, and third part 24 extending from first part 22 toward the outside of case 40 and filler synthetic resin 50, and second part 23 includes at least embedded area 23a embedded in filler synthetic resin 50 and exposed area 23a exposed from filler synthetic resin 50 outside embedded area 23b.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a capacitor in which a capacitor element (2) is housed in a case (5) and filled with resin (6), the capacitor having an electrode plate (3) connected to the capacitor element (2), the electrode plate (3) having a substrate portion (3a) covering the capacitor element (2) from above, and legs (3b) abutting the capacitor element (2) and lifting the substrate portion (3a) above the capacitor element (2), and at least the upper surface of the substrate portion (3a) is exposed outside the resin (6). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-96713 Summary of the Invention [Problem to be solved by the invention]

[0004] In a capacitor module in which a capacitor element is housed inside a case, the capacitor element is generally electrically connected to the outside of the case via a bus bar. In this case, if a large current flows through the bus bar, the bus bar generates heat, and the heat is transferred to the capacitor element, which may reduce the reliability of the capacitor element, for example, shortening the capacitor element's lifespan. Therefore, a capacitor module is required to have a configuration that not only efficiently cools the bus bar, but also efficiently cools the capacitor element via the bus bar.

[0005] In contrast, in the capacitor described in Patent Document 1, at least the upper surface of the substrate portion of the first electrode plate (corresponding to the bus bar) is exposed to the outside of the resin, as shown in Figures 1, 2, 3, etc., and it is said that the first electrode plate can be cooled efficiently. However, in the capacitor described in Patent Document 1, even if an attempt is made to cool the capacitor element via the first electrode plate, the capacitor element can only be cooled along the path connecting from the substrate portion (external connection portion) of the first electrode plate to the element connection portion of the first electrode plate for connection to the capacitor element, so there is room for improvement in terms of efficiently cooling the capacitor element.

[0006] The present invention has been made to solve the above problems, and aims to provide a capacitor module that can efficiently cool not only the bus bars but also the capacitor elements via the bus bars. [Means for solving the problem]

[0007] The capacitor module of the present invention comprises at least one capacitor element, a bus bar electrically connected to the capacitor element and having a terminal on the opposite side to the capacitor element, a case in which the capacitor element is housed so that the terminal is extended to the outside, and filled resin filled inside the case so that the capacitor element is embedded, wherein the bus bar has a first portion connected to the capacitor element and embedded in the filled resin, a second portion protruding from the first portion toward the opposite side to the capacitor element, and a third portion including the terminal and extending from the first portion toward the outside of the case and the filled resin, and the second portion has a buried region embedded in the filled resin at least at the boundary with the first portion, and an exposed region exposed from the filled resin outside the buried region. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a capacitor module that is capable of efficiently cooling not only the bus bars but also the capacitor elements via the bus bars. [Brief explanation of the drawings]

[0009] [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 cross-sectional view schematically showing an example of a cross section of the capacitor module taken along line a1-a2 in FIG. [Figure 3] FIG. 3 is a perspective view schematically showing the capacitor module in FIG. 1 with the filling resin removed. [Figure 4] FIG. 4 is a perspective view schematically showing the capacitor module in FIG. 1 with the filling resin and the case removed. [Figure 5] FIG. 5 is a perspective view schematically showing the capacitor element in FIG. [Figure 6] FIG. 6 is a cross-sectional view schematically showing an example of a cross section of the capacitor element taken along line b1-b2 in FIG. [Figure 7] FIG. 7 is a perspective view schematically showing the first bus bar in FIG. [Figure 8] FIG. 8 is a plan view schematically showing the first bus bar in FIG. 7 as viewed from a first direction. [Figure 9] FIG. 9 is a perspective view schematically illustrating an example of a first bus bar in which the position of the second portion is different from that in FIG. [Figure 10] FIG. 10 is a perspective view schematically illustrating an example of a first bus bar having a different number of second portions from that of FIG. [Figure 11] FIG. 11 is a perspective view that schematically shows an example of a first bus bar in which the three-dimensional shape of the second portion is different from those in FIGS. 7, 9, and 10. In FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] The capacitor module of the present invention will be described below. Note that the present invention is not limited to the following configuration and may be modified as appropriate without departing from the spirit of the present invention. In addition, a combination of multiple individual preferred configurations described below also constitutes the present invention.

[0011] The drawings shown below are schematic diagrams, and the dimensions, aspect ratio, scale, etc. may differ from those of the actual product.

[0012] 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.

[0013] [Capacitor module] The capacitor module of the present invention comprises at least one capacitor element, a bus bar electrically connected to the capacitor element and having a terminal on the opposite side to the capacitor element, a case in which the capacitor element is housed so that the terminal is extended to the outside, and filled resin filled inside the case so that the capacitor element is embedded, wherein the bus bar has a first portion connected to the capacitor element and embedded in the filled resin, a second portion protruding from the first portion toward the opposite side to the capacitor element, and a third portion including the terminal and extending from the first portion toward the outside of the case and the filled resin, and the second portion has a buried region embedded in the filled resin at least at the boundary with the first portion, and an exposed region exposed from the filled resin outside the buried region.

[0014] In the capacitor module of the present invention, the bus bar has a first portion connected to the capacitor element and embedded in the filled resin, a second portion protruding from the first portion toward the side opposite the capacitor element, and a third portion including terminals and extending from the first portion toward the outside of the case and the filled resin. Furthermore, in the capacitor module of the present invention, the second portion has an embedded region embedded in the filled resin at least at the boundary with the first portion and an exposed region exposed from the filled resin outside the embedded region. As described above, in the capacitor module of the present invention, not only is the third portion of the bus bar exposed from the filled resin at least at the terminals, but the second portion is also exposed from the filled resin in the exposed region. Therefore, in the capacitor module of the present invention, it is possible to directly cool the bus bar not only in the third portion but also in the second portion. Furthermore, in the capacitor module of the present invention, it is possible to cool the capacitor element via the bus bar not only through the path connecting the third portion to the first portion but also through the path connecting the second portion to the first portion. Thus, the capacitor module of the present invention has more paths for cooling the capacitor element than, for example, the capacitor described in Patent Document 1. Therefore, in the capacitor module of the present invention, it is possible to efficiently cool not only the bus bars but also the capacitor elements via the bus bars. In this way, in the capacitor module of the present invention, it is possible to efficiently cool not only the bus bars but also the capacitor elements via the bus bars, which leads to improved heat resistance, which is related to the reliability of the capacitor module of the present invention.

[0015] A specific example of the capacitor module of the present invention will be described below.

[0016] Fig. 1 is a perspective view schematically showing an example of a capacitor module of the present invention. Fig. 2 is a cross-sectional view schematically showing an example of a cross-section along line a1-a2 of the capacitor module in Fig. 1. Fig. 3 is a perspective view schematically showing a state in which the filling resin has been removed from the capacitor module in Fig. 1. Fig. 4 is a perspective view schematically showing a state in which the filling resin and the case have been removed from the capacitor module in Fig. 1.

[0017] As shown in FIGS. 1, 2, 3, and 4, the capacitor module 1 includes a capacitor element 10, a first bus bar 20, a second bus bar 30, a case 40, and a filled resin 50.

[0018] In FIG. 1 and other figures, the first direction D1, the second direction D2, and the third direction D3 are perpendicular to one another.

[0019] Each component of the capacitor module 1 will be described below.

[0020] <Capacitor element> Fig. 5 is a perspective view schematically showing the capacitor element in Fig. 4. Fig. 6 is a cross-sectional view schematically showing an example of a cross section of the capacitor element in Fig. 5 taken along line b1-b2.

[0021] As shown in FIGS. 5 and 6, capacitor element 10 has element body 11, first external electrode 12a, and second external electrode 12b.

[0022] Body 11 is a wound body formed by winding first metallized film 13a and second metallized film 13b in a stacked state in third direction D3. That is, capacitor element 10 is a wound-type film capacitor formed by winding metallized films in a stacked state.

[0023] Capacitor element 10 may be a laminated film capacitor (for example, rectangular parallelepiped) formed by laminating metallized films.

[0024] The element body 11 has a first end face 11a and a second end face 11b facing each other in the first direction D1.

[0025] The element body 11 further has a side surface 11c extending in the first direction D1 so as to connect the peripheries of the first end surface 11a and the second end surface 11b.

[0026] 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 (first direction D1 in FIGS. 5 and 6) 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.

[0027] Whether or not element body 11 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 element body 11.

[0028] 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.

[0029] First metallized film 13a includes first dielectric film 14a and first metal layer 15a.

[0030] The first dielectric film 14a has a first main surface 14aa and a second main surface 14ab facing each other in the third direction D3.

[0031] 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 first direction D1 but not to reach the other side edge of the first dielectric film 14a.

[0032] Second metallized film 13b includes second dielectric film 14b and second metal layer 15b.

[0033] The second dielectric film 14b has a first main surface 14ba and a second main surface 14bb that face each other in the third direction D3.

[0034] 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 first direction D1 but to reach the other side edge of the second dielectric film 14b.

[0035] In element body 11, adjacent first metallized films 13a and second metallized films 13b are offset in first direction D1 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.

[0036] In element body 11, adjacent first metallized films 13a and second metallized films 13b are misaligned in first direction D1 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.

[0037] Since element body 11 is formed by winding first metallized film 13a and second metallized film 13b in a stacked state in third direction D3, 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 third direction D3. 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 third direction D3.

[0038] 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 third direction D3, and second main surface 14ab of first dielectric film 14a and first main surface 14ba of second dielectric film 14b face each other in third direction D3. Thus, in element body 11, first metallized film 13a and second metallized film 13b are wound in a stacked state in third direction D3. In other words, in element body 11, first metallized film 13a and second metallized film 13b are wound in a stacked state in third direction D3 so that second metallized film 13b is on the inside of first metallized film 13a, specifically, so that first metal layer 15a is on the inside of first dielectric film 14a and so that 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.

[0039] 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.

[0040] Similar to the first metal layer 15a, the second metal layer 15b may also be provided with a fuse portion.

[0041] The first dielectric film 14a may contain a curable resin as a main component.

[0042] 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.

[0043] The curable resin may be a thermosetting resin or a photocurable resin.

[0044] 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.).

[0045] 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.

[0046] The presence of urethane bonds in the dielectric film can be confirmed by analysis using a Fourier transform infrared spectroscopy (FT-IR).

[0047] 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.

[0048] The presence of hydroxyl groups and / or isocyanate groups in the dielectric film can be confirmed by analysis with a Fourier transform infrared spectrophotometer (FT-IR).

[0049] Examples of the first organic material include phenoxy resin, polyvinyl acetoacetal resin, and polyvinyl butyral resin.

[0050] As the first organic material, a plurality of types of organic materials may be used in combination.

[0051] 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.

[0052] As the second organic material, a plurality of types of organic materials may be used in combination.

[0053] The first dielectric film 14a may contain a thermoplastic resin as a main component.

[0054] Examples of the thermoplastic resin include polypropylene resin, polyethersulfone resin, polyetherimide resin, and polyarylate resin.

[0055] The first dielectric film 14a may further contain additives to impart various functions.

[0056] The additives include, for example, a leveling agent for imparting smoothness.

[0057] 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.

[0058] 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 further contain an additive.

[0059] The first dielectric film 14a and the second dielectric film 14b may have different compositions, but preferably have the same composition.

[0060] 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.

[0061] 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.

[0062] The thickness of the dielectric film is measured using an optical film thickness gauge.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] The thickness of the metal layer is measured by observing a cross section of the metallized film taken along the third direction using a transmission electron microscope (TEM).

[0069] 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.

[0070] 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.

[0071] The first external electrode 12a is provided on the surface of the element body 11. In the example shown in Figures 5 and 6, 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.

[0072] 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 5 and 6, 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.

[0073] The first external electrode 12a and the second external electrode 12b have different polarities. For example, the first external electrode 12a may be a positive electrode (P electrode) and the second external electrode 12b may be a negative electrode (N electrode), or the first external electrode 12a may be a negative electrode (N electrode) and the second external electrode 12b may be a positive electrode (P electrode).

[0074] 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.

[0075] The first external electrode 12a and the second external electrode 12b may have different compositions, but preferably have the same composition.

[0076] 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.

[0077] The above configuration is merely one example of capacitor element 10. In other words, capacitor element 10 is not limited to the above configuration.

[0078] Although the above describes an example in which capacitor element 10 is a film capacitor, capacitor element 10 may be a capacitor element other than a film capacitor.

[0079] There is no particular limitation on the number of capacitor elements 10 in the capacitor module 1. In other words, the capacitor module 1 only needs to have at least one capacitor element 10, and specifically, it may have one capacitor element 10, or may have multiple capacitor elements 10 as shown in FIG. 4 etc.

[0080] When the capacitor module 1 has a plurality of capacitor elements 10, the configurations of the plurality of capacitor elements 10 may be the same as one another, may be different from one another, or may be partially different from one another.

[0081] When the capacitor module 1 has multiple capacitor elements 10, the arrangement of the multiple capacitor elements 10 when housed inside the case 40 (described later) is not particularly limited. For example, the multiple capacitor elements 10 may be arranged in a single row or multiple rows when housed inside the case 40 (described later). When the multiple capacitor elements 10 are arranged in multiple rows, the multiple capacitor elements 10 may be arranged in multiple rows in one direction or multiple rows in multiple directions.

[0082] <First bus bar> The first bus bar 20 is electrically connected to the capacitor element 10. For example, as follows.

[0083] The first bus bar 20 is electrically connected to the first external electrode 12a of the capacitor element 10. The first bus bar 20 may be connected to the first external electrode 12a by, for example, welding or via a joining member such as solder.

[0084] As a result, the first external electrode 12a of the capacitor element 10 is electrically drawn out via the first bus bar 20. When the first external electrode 12a is a positive electrode, the first bus bar 20 serves as a lead conductor for the positive electrode.

[0085] The first bus bar 20 has a first terminal 21 on the side opposite to the capacitor element 10. To the first terminal 21, for example, a component such as a power module is electrically connected.

[0086] There is no particular limitation on the number of first terminals 21 in first bus bar 20. In other words, first bus bar 20 may have one first terminal 21 as shown in FIG.

[0087] The position of the first terminal 21 that is drawn out to the outside of the case 40, which will be described later, is not particularly limited.

[0088] Examples of materials that can be used to form first bus bar 20 include metals such as copper, oxygen-free copper, aluminum, and alloys containing at least one of these. Among these, the material that can be used to form first bus bar 20 is preferably copper or oxygen-free copper. When first bus bar 20 is 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).

[0089] <Second bus bar> The second bus bar 30 is electrically connected to the capacitor element 10. For example, as follows.

[0090] The second bus bar 30 is electrically connected to the second external electrode 12b of the capacitor element 10. The second bus bar 30 may be connected to the second external electrode 12b by, for example, welding or via a joining member such as solder.

[0091] As a result, the second external electrode 12b of the capacitor element 10 is electrically drawn out via the second bus bar 30. When the second external electrode 12b is a negative electrode, the second bus bar 30 serves as a drawing conductor for the negative electrode.

[0092] The second bus bar 30 has a second terminal 31 on the side opposite to the capacitor element 10. To the second terminal 31, for example, a component such as a power module is electrically connected.

[0093] There is no particular limitation on the number of second terminals 31 in the second bus bar 30. In other words, the second bus bar 30 may have one second terminal 31 as shown in FIG.

[0094] The position of the second terminal 31 that is drawn out to the outside of the case 40 (described later) is not particularly limited.

[0095] Examples of materials that can be used for the second bus bar 30 include metals such as copper, oxygen-free copper, aluminum, and alloys containing at least one of these. Among these, the material for the second bus bar 30 is preferably copper or oxygen-free copper. When the material for the second bus bar 30 is 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).

[0096] The material of the second bus bar 30 may be the same as the material of the first bus bar 20, or may be different from the material of the first bus bar 20.

[0097] The thickness of the second bus bar 30 may be the same as the thickness of the first bus bar 20 or may be different from the thickness of the first bus bar 20.

[0098] <Case> The capacitor element 10 is housed inside the case 40 such that the first terminal 21 and the second terminal 31 are drawn to the outside. As a result, the first external electrode 12a (e.g., the positive electrode of the capacitor element 10) is electrically drawn to the outside of the case 40 via the first bus bar 20 (first terminal 21), and the second external electrode 12b (e.g., the negative electrode of the capacitor element 10) is electrically drawn to the outside of the case 40 via the second bus bar 30 (second terminal 31).

[0099] It is preferable that capacitor element 10 is housed inside case 40 so as to be separated from the inner surface of case 40 .

[0100] The shape of the case 40 is not particularly limited.

[0101] 1 etc., the case 40 is a cylindrical shape with a bottom and provided with an opening 41. Specifically, the case 40 is a cylindrical shape with a bottom and provided with the opening 41 at one end in the first direction D1.

[0102] In the example shown in Figure 1, etc., the case 40 has a bottom 42 facing the opening 41 in the first direction D1, and a side wall 43 (in Figure 1, etc., it includes four side wall 43) extending from the bottom 42 toward the opening 41 in the first direction D1.

[0103] The case 40 may be, for example, a resin case or a metal case.

[0104] When case 40 is a resin case, examples of the resin that constitutes the resin case include liquid crystal polymer, polyphenylene sulfide resin, polybutylene terephthalate resin, etc. Among these, it is preferable that the resin case contains a liquid crystal polymer.

[0105] 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.

[0106] The resin case preferably further contains an inorganic filler in addition to the liquid crystal polymer.

[0107] 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.

[0108] 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, multiple types 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.

[0109] 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.

[0110] 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.

[0111] It is preferable that at least a portion of the inorganic filler has, in the side wall portion 43 of the case 40, a portion oriented in a direction from the bottom 42 side toward the opening 41 side and a portion oriented in the outer circumferential direction of the side wall portion 43, and is dispersed inside the case 40.

[0112] The inorganic filler preferably has a diameter of 5 μm or more and a length of 50 μm or more.

[0113] The inorganic filler is preferably dispersed throughout the case 40 without agglomerating.

[0114] 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.

[0115] 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.

[0116] The resin case is manufactured by a method such as injection molding or 3D printing (three-dimensional modeling).

[0117] When case 40 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.

[0118] The metal case is manufactured by a method such as impact molding or 3D printing (three-dimensional modeling).

[0119] <Filled resin> Filling resin 50 is filled inside case 40 so that capacitor element 10 is embedded therein. As a result, capacitor element 10 is fixed inside case 40 by filling resin 50. Furthermore, filling resin 50 prevents moisture from penetrating capacitor element 10, thereby preventing deterioration of capacitor element 10.

[0120] When capacitor element 10 is housed inside case 40 so as to be spaced apart from the inner surface of case 40, it is preferable that filling resin 50 be filled between capacitor element 10 and case 40, specifically between the outer surface of capacitor element 10 and the inner surface of case 40. Furthermore, it is preferable that filling resin 50 be filled inside case 40 not only between capacitor element 10 and case 40 but also in the region from opening 41 of case 40 to capacitor element 10.

[0121] From the viewpoint of suppressing the penetration of moisture into capacitor element 10, it is preferable that the thickness of filling resin 50 at opening 41 of case 40 is large. The thickness of filling resin 50 at opening 41 of case 40 is preferably sufficiently large within the range allowed by the overall volume (physical size) of capacitor element 10 and case 40, and specifically, is preferably 2 mm or more, and more preferably 4 mm or more. In particular, it is preferable that, inside case 40, capacitor element 10 is disposed closer to bottom 42 than to opening 41, so that the thickness of filling resin 50 relative to capacitor element 10 is larger on the opening 41 side than on the bottom 42 side.

[0122] The thickness of the filled resin 50 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 vernier caliper if it is in a destructive state.

[0123] The relationship between the height of the case 40 and the height of the filling resin 50 in the first direction D1 is such that the thickness of the filling resin 50 at the opening 41 of the case 40 is as large as possible, and it may be up to a position inside the case 40, or it may be just about to the top, or it may overflow slightly due to surface tension.

[0124] 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 50, 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.

[0125] The above-mentioned resin alone may be used as the filling resin 50, 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.

[0126] The following describes the configuration of the bus bars, which are a feature of the capacitor module 1.

[0127] As shown in FIG. 1 and other figures, in the capacitor module 1, the first bus bar 20 has a first portion 22, a second portion 23, and a third portion 24.

[0128] The first portion 22 is connected to the capacitor element 10. In the example shown in FIG.

[0129] The first portion 22 is embedded in the filled resin 50. As a result, the first bus bar 20 is fixed at the first portion 22 by the filled resin 50.

[0130] The second portion 23 protrudes from the first portion 22 toward the side opposite the capacitor element 10. In the example shown in FIG. 2 etc., the second portion 23 protrudes from the first portion 22 toward the side opposite the capacitor element 10 in the first direction D1. In this way, the second portion 23 is a portion that is three-dimensionally deformed from the first portion 22.

[0131] The second portion 23 has a buried region 23a that is buried in the filling resin 50 at least at the boundary with the first portion 22, and an exposed region 23b that is exposed from the filling resin 50 other than the buried region 23a. In the example shown in Fig. 2 etc., the second portion 23 is connected to the first portion 22 at both ends in the second direction D2. Furthermore, the second portion 23 has buried regions 23a at both ends in the second direction D2, and an exposed region 23b between the buried regions 23a in the second direction D2.

[0132] 2 and other examples, in exposed region 23b of second portion 23, of a pair of main surfaces facing each other in first direction D1, not only the main surface opposite to filled resin 50 but also the main surface facing the filled resin 50 are separated from the filled resin 50, but the main surface facing the filled resin 50 may be in contact with the filled resin 50 while the main surface opposite to filled resin 50 is separated from the filled resin 50. In this way, it is sufficient that at least a portion of exposed region 23b of second portion 23 is exposed from the filled resin 50.

[0133] The third portion 24 includes the first terminal 21. In the example shown in Fig. 2 etc., the third portion 24 includes the first terminal 21 on the opposite side to the first portion 22 and the second portion 23 in the second direction D2.

[0134] The third portion 24 extends from the first portion 22 toward the outside of the case 40 and the filled resin 50. In the example shown in FIG. 2 etc., the third portion 24 extends from the first portion 22 toward the outside of the case 40 and the filled resin 50, toward the opposite side of the first portion 22 and the second portion 23 in the second direction D2. In this manner, the third portion 24 is exposed from the filled resin 50 at least at the first terminal 21. As long as the third portion 24 is exposed from the filled resin 50 at least at the first terminal 21, the third portion 24 may be embedded in the filled resin 50 on the side opposite the first terminal 21, i.e., on the first portion 22 side.

[0135] As described above, in the capacitor module 1, not only is the third portion 24 of the first bus bar 20 exposed from the filled resin 50 at least at the first terminal 21, but the second portion 23 is also exposed from the filled resin 50 in the exposed region 23b. Therefore, in the capacitor module 1, it is possible to directly cool not only the third portion 24 of the first bus bar 20 but also the second portion 23 (exposed region 23b). Furthermore, in the capacitor module 1, it is possible to cool the capacitor element 10 via the first bus bar 20 not only in the path connecting the third portion 24 to the first portion 22 but also in the path connecting the second portion 23 to the first portion 22. Thus, in the capacitor module 1, there are more paths available for cooling the capacitor element 10 than in the capacitor described in Patent Document 1, for example. Therefore, in the capacitor module 1, it is possible to efficiently cool not only the first bus bar 20 but also the capacitor element 10 via the first bus bar 20. In this way, if the capacitor module 1 can efficiently cool not only the first bus bar 20 but also the capacitor element 10 via the first bus bar 20, this will lead to improved heat resistance, which is related to the reliability of the capacitor module 1.

[0136] As described above, in the capacitor module 1, the first portion 22 of the first bus bar 20 is mainly used for connecting to the capacitor element 10, and the second portion 23 and the third portion 24 are mainly used not only for cooling the first bus bar 20 but also for cooling the capacitor element 10 via the first bus bar 20.

[0137] Methods for directly cooling the first busbar 20 at the second portion 23 and the third portion 24 include, for example, air-cooling the second portion 23 and the third portion 24, or contacting a cooling body such as a heat sink with the second portion 23 and the third portion 24.

[0138] A specific embodiment of the first bus bar 20 will be described below.

[0139] Fig. 7 is a perspective view schematically showing the first bus bar in Fig. 4. Fig. 8 is a plan view schematically showing the first bus bar in Fig. 7 as viewed from a first direction.

[0140] 7 and 8, it is preferable that exposed region 23b is wider than buried region 23a in first bus bar 20. In this case, first bus bar 20 can be more easily cooled directly in second portion 23 (exposed region 23b). Furthermore, because first bus bar 20 can be more easily cooled directly over a wider region (area) in second portion 23 (exposed region 23b), not only first bus bar 20 but also capacitor element 10 can be more easily cooled quickly via first bus bar 20.

[0141] When comparing the sizes (areas) of buried region 23a and exposed region 23b in first busbar 20, the sizes (areas) of the entire buried region 23a and exposed region 23b are compared. For example, if there are multiple buried regions 23a, the overall sizes (areas) of the multiple buried regions 23a are compared, and if there are multiple exposed regions 23b, the overall sizes (areas) of the multiple exposed regions 23b are compared.

[0142] 7 and 8, in the first bus bar 20, the second portion 23 may be connected to the first portion 22 at a pair of opposing sides of the periphery and separated from the first portion 22 at another pair of opposing sides of the periphery. In the example shown in Figures 7 and 8, the second portion 23 is connected to the first portion 22 at a pair of sides of the periphery facing the second direction D2 and separated from the first portion 22 at another pair of sides of the periphery facing the third direction D3. In other words, in the example shown in Figures 7 and 8, the second portion 23 protrudes in an arch shape from the first portion 22.

[0143] 8 may be provided along another pair of sides of the periphery of the second portion 23 that face the third direction D3, and then bending may be performed on the portion between the pair of slits 25. Note that, when the second portion 23 protrudes in an arch shape from the first portion 22, a pair of linear cuts may be provided instead of the pair of slits 25, and then bending may be performed on the portion between the pair of cuts.

[0144] When the second portion 23 is arch-shaped, when the second portion 23 is viewed in cross section (here, when a cross section along the first direction D1 and the second direction D2 is viewed), the cross-sectional shape of the second portion 23 may be composed of straight lines, curved lines, or a combination of straight lines and curved lines.

[0145] When the cross-sectional shape of second portion 23 is configured with straight lines, the cross-sectional shape of second portion 23 is not particularly limited, and may include, for example, a linearly inclined portion or a stepped inclined portion from both ends toward the inside as shown in Fig. 2. Furthermore, the cross-sectional shape of second portion 23 may include a portion that extends linearly along the surface of filled resin 50 (here, in second direction D2) in exposed region 23b.

[0146] When the cross-sectional shape of the second portion 23 is configured by a curve, the cross-sectional shape of the second portion 23 is not particularly limited, and may include, for example, portions that slope in an arc shape from both ends inward.

[0147] In the example shown in FIG. 7, second portion 23 is spaced apart from both of a pair of sides of the periphery of first bus bar 20 that face each other in third direction D3.

[0148] The position of the second portion 23 of the first bus bar 20 is not limited to the position shown in FIG.

[0149] FIG. 9 is a perspective view schematically illustrating an example of a first bus bar in which the position of the second portion is different from that in FIG.

[0150] In the example shown in FIG. 9, the second portion 23 is spaced apart from one of a pair of sides of the periphery of the first busbar 20 that face the third direction D3 and is in contact with the other side (i.e., it constitutes the other side).

[0151] In the example shown in FIG. 7, the first bus bar 20 has one second portion 23.

[0152] The number of second portions 23 in first bus bar 20 is not limited to one as shown in FIG. 7, and may be plural.

[0153] FIG. 10 is a perspective view schematically illustrating an example of a first bus bar having a different number of second portions from that of FIG.

[0154] In the example shown in FIG. 10, the first bus bar 20 has two second portions 23.

[0155] 10 , one of the two second portions 23 is spaced from one of a pair of sides of the periphery of the first bus bar 20 facing the third direction D3 and is in contact with the other side (i.e., forms the other side). Furthermore, the other of the two second portions 23 is in contact with one of a pair of sides of the periphery of the first bus bar 20 facing the third direction D3 (i.e., forms one side) and is spaced from the other side.

[0156] The three-dimensional shape of the second portion 23 is not limited to the three-dimensional shapes shown in FIGS.

[0157] FIG. 11 is a perspective view that schematically shows an example of a first bus bar in which the three-dimensional shape of the second portion is different from those in FIGS. 7, 9, and 10. In FIG.

[0158] 11, the entire periphery of the second portion 23 is connected to the first portion 22. To make the second portion 23 protrude from the first portion 22 in this manner, for example, a drawing process may be performed on a predetermined location of the first portion 22.

[0159] In the first busbar 20, when the first busbar 20 is viewed in a plane, the second portion 23 may be surrounded by the first portion 22. For example, when the first busbar 20 shown in FIG. 7 is viewed in a plane as shown in FIG. 8, the entire periphery (here, all four sides) of the second portion 23 is surrounded by the first portion 22. Similarly, in the first busbar 20 shown in FIGS. 9, 10, and 11, when the first busbar 20 is viewed in a plane, at least a part of the periphery of the second portion 23 is surrounded by the first portion 22.

[0160] In the above, an example has been shown in which the second portion 23 of the first bus bar 20 is connected to the first portion 22 at both ends in a certain direction (the second direction D2 in FIG. 7 and other figures), but the second portion 23 may be connected to the first portion 22 at one end in that direction (for example, the second direction D2) or may not be connected to the first portion 22 at the other end in that direction (for example, the second direction D2). In this case, the second portion 23 may be embedded in the filling resin 50 at one end side connected to the first portion 22 (for example, one end side in the second direction D2) as the embedded region 23a, and may be exposed from the filling resin 50 at the other end side not connected to the first portion 22 (for example, the other end side in the second direction D2) as the exposed region 23b.

[0161] As shown in Fig. 4 and other figures, in the capacitor module 1, it is preferable that the first portion 22 is connected to the capacitor element 10 in a planar manner. In this case, it is easier to connect the first bus bar 20 to the capacitor element 10 at the first portion 22. Furthermore, since heat is more easily transferred from the first portion 22 to the capacitor element 10, it becomes easier to quickly cool the capacitor element 10 via the first bus bar 20 in the path connecting the second portion 23 to the first portion 22 and in the path connecting the third portion 24 to the first portion 22.

[0162] As described above, the configuration in which the first portion 22 is connected to the capacitor element 10 in a planar manner is similarly preferable not only for the first bus bar 20 shown in Figure 7, but also for the first bus bar 20 shown in Figures 9, 10, and 11.

[0163] 4 and other figures, when a plurality of capacitor elements 10 are present in the capacitor module 1, it is preferable that the first portion 22 spans the plurality of capacitor elements 10. In this case, the first bus bar 20 can be easily connected to the plurality of capacitor elements 10 at the first portion 22. Furthermore, since heat is easily transferred from the first portion 22 to the plurality of capacitor elements 10, the plurality of capacitor elements 10 can be easily cooled via the first bus bar 20 in the path connecting the second portion 23 to the first portion 22 and in the path connecting the third portion 24 to the first portion 22.

[0164] As described above, the aspect in which the first portion 22 spans multiple capacitor elements 10 is similarly preferable not only for the first bus bar 20 shown in Figure 7, but also for the first bus bar 20 shown in Figures 9, 10, and 11.

[0165] 4 and other figures, when the capacitor module 1 includes a plurality of capacitor elements 10 and the first portion 22 spans the plurality of capacitor elements 10, it is preferable that the second portion 23 also spans the plurality of capacitor elements 10. In this case, the first bus bar 20 can be easily cooled directly over a wide region (area) in the second portion 23 (exposed region 23b), and therefore not only the first bus bar 20 but also the plurality of capacitor elements 10 via the first bus bar 20 can be easily cooled quickly.

[0166] As described above, the aspect in which the second portion 23 spans multiple capacitor elements 10 is similarly preferable not only for the first bus bar 20 shown in Figure 7, but also for the first bus bar 20 shown in Figures 9, 10, and 11.

[0167] Although the configuration of the first bus bar 20 has been shown above as an example of the configuration of the bus bar that is a feature of the capacitor module 1, the configuration of the second bus bar 30 may also be the configuration described above.

[0168] 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.

[0169] 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.

[0170] The capacitor module of the present invention is applicable not only to in-vehicle applications but also to various fields such as power electronics.

[0171] The present specification discloses the following:

[0172] <1> at least one capacitor element; a bus bar electrically connected to the capacitor element and having a terminal on the opposite side to the capacitor element; a case in which the capacitor element is housed so that the terminals are extended to the outside; a filling resin filled inside the case so that the capacitor element is embedded therein; the bus bar has a first portion connected to the capacitor element and embedded in the filling resin, a second portion protruding from the first portion toward an opposite side to the capacitor element, and a third portion including the terminal and extending from the first portion toward an outside of the case and the filling resin, A capacitor module characterized in that the second portion has a buried region embedded in the filling resin at least at the boundary with the first portion, and an exposed region exposed from the filling resin outside the buried region.

[0173] <2> the exposed region is larger than the buried region; <1> The capacitor module according to claim 1.

[0174] <3> the second portion is connected to the first portion at a pair of opposing sides of the periphery and is separated from the first portion at another pair of opposing sides of the periphery; <1> or <2> The capacitor module according to claim 1.

[0175] <4> When the bus bar is viewed from above, the second portion is surrounded by the first portion. <1> ~ <3> 10. The capacitor module according to claim 9, wherein the capacitor module is a capacitor module having a capacitance of 100.degree.

[0176] <5> the first portion is connected to the capacitor element in a planar manner; <1> ~ <4> 10. The capacitor module according to claim 9, wherein the capacitor module is a capacitor module having a capacitance of 100.degree.

[0177] <6> There are a plurality of the capacitor elements, the first portion extends across a plurality of the capacitor elements; <1> ~ <5> 10. The capacitor module according to claim 9, wherein the capacitor module is a capacitor module having a capacitance of 100.degree.

[0178] <7> the second portion extends across a plurality of the capacitor elements; <6> The capacitor module according to claim 1.

[0179] <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]

[0180] 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 No. 1 bus bar 21 1st terminal 22 Part 1 23 Part 2 23a Buried area 23b Exposed area 24 Part 3 25 slit 30 Second bus bar 31 2nd terminal 40 cases 41 Opening 42 Bottom 43 Side wall 50 Filled Resin D1 1st direction D2 2nd direction D3 Third direction

Claims

1. at least one capacitor element; a bus bar electrically connected to the capacitor element and having a terminal on the opposite side to the capacitor element; a case in which the capacitor element is housed so that the terminals are extended to the outside; a filling resin filled inside the case so that the capacitor element is embedded therein; the bus bar has a first portion connected to the capacitor element and embedded in the filling resin, a second portion protruding from the first portion toward an opposite side to the capacitor element, and a third portion including the terminal and extending from the first portion toward an outside of the case and the filling resin, A capacitor module characterized in that the second portion has a buried region embedded in the filling resin at least at the boundary with the first portion, and an exposed region exposed from the filling resin outside the buried region.

2. The capacitor module of claim 1 , wherein the exposed area is larger than the buried area.

3. The capacitor module according to claim 1 or 2, wherein the second portion is connected to the first portion at a pair of opposing sides of the periphery and is separated from the first portion at another pair of opposing sides of the periphery.

4. The capacitor module according to claim 1 , wherein the second portion is surrounded by the first portion when the bus bar is viewed from above.

5. The capacitor module according to claim 1 or 2, wherein the first portion is connected to the capacitor element in a planar manner.

6. There are a plurality of the capacitor elements, The capacitor module according to claim 1 , wherein the first portion spans a plurality of the capacitor elements.

7. The capacitor module according to claim 6 , wherein the second portion spans a plurality of the capacitor elements.

8. The capacitor module according to claim 1 or 2, wherein the capacitor element is a film capacitor.

Images