Capacitor module

Abstract

A capacitor module 1 is characterized by comprising: at least one capacitor element 10 that has external electrodes (first external electrode 12a, second external electrode 12b); element connection bus bars (first element connection bus bar 20a, second element connection bus bar 20b) that are each electrically connected to an external electrode (first external electrode 12a, second external electrode 12b); external connection bus bars (first external connection bus bar 30a, second external connection bus bar 30b) that each have an external connection terminal 31a, 31b on the opposite side from the capacitor element 10, and that are each electrically connected to an external electrode (first external electrode 12a, second external electrode 12b) via an element connection bus bar (first element connection bus bar 20a, second element connection bus bar 20b); and a sealing material 50 that seals the capacitor element 10, the element connection bus bars (first element connection bus bar 20a, second element connection bus bar 20b), and the external connection bus bars (first external connection bus bar 30a, second external connection bus bar 30b) in such a manner that the external connection terminals 31a, 31b are led to the outside, wherein the element connection bus bars (first element connection bus bar 20a, second element connection bus bar 20b) each have an opening 21a, 21b and cover the entirety of a respective external electrode (first external electrode 12a, second external electrode 12b) except for the part overlapping with the opening 21a, 21b.

Description

Capacitor module

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

[0002] Patent Document 1 discloses a capacitor in which a capacitor element having electrode portions at both ends and a pair of external connection electrode plates having external connection portions are housed in a case, and the capacitor element is connected to the external connection electrode plates via an element electrode plate, and the inside of the case is filled with a filling resin so as to embed the capacitor element.

[0003] Japanese Patent Application Laid-Open No. 2019-33133

[0004] As disclosed in Patent Document 1, as a conventional capacitor, the element electrode plate includes a substrate portion, an element connection piece for connecting to the electrode portion (also referred to as an external electrode) of the capacitor element, and an electrode plate connection piece for connecting to the external connection electrode plate, and it is known that a part of the electrode portion of the capacitor element is covered.

[0005] In a conventional capacitor using a filling resin (also referred to as a sealing material) as disclosed in Patent Document 1, when the temperature of the use environment changes rapidly, stress is generated in the electrode portion of the capacitor element due to the difference in the thermal expansion coefficients of the capacitor element and the filling resin. Here, in the capacitor described in Patent Document 1, although a part of the electrode portion of the capacitor element is covered with the element electrode plate, most of the rest is in contact with the filling resin. Therefore, in the capacitor described in Patent Document 1, due to the difference in the thermal expansion coefficients of the capacitor element and the filling resin as described above, stress is likely to be generated in the electrode portion of the capacitor element that is mostly in contact with the filling resin, and as a result, cracks occur inside the electrode portion with the weakest strength. When cracks occur inside the electrode portion of the capacitor element, there is a risk that the electrical characteristics of the capacitor element will deteriorate, such as an increase in the equivalent series resistance (Equivalent Series Resistance: ESR) of the capacitor element.

[0006] The present invention was made to solve the above problems and aims to provide a capacitor module that can prevent the occurrence of cracks inside the external electrodes of the capacitor element even when the temperature of the operating environment changes.

[0007] The capacitor module of the present invention comprises at least one capacitor element having external electrodes, an element connection busbar electrically connected to the external electrodes, an external connection busbar having external connection terminals on the opposite side of the capacitor element and electrically connected to the external electrodes via the element connection busbar, and a sealing material that seals the capacitor element, the element connection busbar and the external connection busbar so that the external connection terminals are brought out to the outside, wherein the element connection busbar has an opening and covers the entire external electrode except for the portion that overlaps the opening.

[0008] According to the present invention, it is possible to provide a capacitor module that can prevent the occurrence of cracks inside the external electrodes of the capacitor element even when the temperature of the operating environment changes.

[0009] Figure 1 is a schematic diagram showing an example of a capacitor module of the present invention in a perspective view. Figure 2 is a schematic diagram showing the capacitor module shown in Figure 1 with the encapsulant removed. Figure 3 is a schematic diagram showing the structure shown in Figure 2 in a disassembled state. Figure 4 is a schematic diagram showing an example of a capacitor element shown in Figure 2 in a perspective view. Figure 5 is a schematic diagram showing an example of a cross-sectional view of the capacitor element shown in Figure 4 along the line segment a1-a2. Figure 6 is a schematic diagram showing the stress state of the capacitor element shown in Figure 2. Figure 7 is a schematic diagram showing an example of a view of the structure shown in Figure 2 along the line segment b1-b2. Figure 8 is a schematic diagram showing another example of a capacitor module of the present invention in a perspective view. Figure 9 is a schematic diagram showing an example of a disassembled capacitor module (excluding the encapsulant) shown in Figure 8.

[0010] The capacitor module of the present invention will be described below. However, the present invention is not limited to the configuration described below, and may be modified as appropriate without departing from the spirit of the invention. Furthermore, a combination of several of the preferred configurations described below also constitutes the present invention.

[0011] In the following description, unless otherwise specified, each embodiment will simply be referred to as "the capacitor module of the present invention."

[0012] In the following, a film capacitor is shown as an example of a capacitor element in the capacitor module of the present invention. The capacitor module of the present invention is also applicable to capacitor elements other than film capacitors.

[0013] The drawings shown below are schematic representations, and their dimensions, aspect ratios, and scales may differ from those of the actual product.

[0014] In this specification, unless otherwise specified, terms describing relationships between elements (e.g., "parallel," "perpendicular," etc.) and terms describing the shape of elements mean not only their literal, exact form, but also a range that is substantially equivalent, for example, a range that includes differences of a few percent.

[0015] The capacitor module of the present invention comprises at least one capacitor element having external electrodes, an element connection busbar electrically connected to the external electrodes, an external connection busbar having external connection terminals on the opposite side of the capacitor element and electrically connected to the external electrodes via the element connection busbar, and a sealing material that seals the capacitor element, the element connection busbar and the external connection busbar so that the external connection terminals are brought out to the outside, wherein the element connection busbar has an opening and covers the entire external electrode except for the portion that overlaps the opening.

[0016] Figure 1 is a schematic diagram showing an example of the capacitor module of the present invention in a perspective view. Figure 2 is a schematic diagram showing the capacitor module shown in Figure 1 with the encapsulating material removed. Figure 3 is a schematic diagram showing the structure shown in Figure 2 in a disassembled state.

[0017] The capacitor module 1 shown in Figures 1, 2, and 3 comprises capacitor elements 10a, 10b, and 10c, a busbar 20a for connecting a first element, a busbar 20b for connecting a second element, a busbar 30a for connecting a first external element, a busbar 30b for connecting a second external element, and a sealing material 50.

[0018] In Figure 1, etc., the first direction D1, the second direction D2, and the third direction D3 are perpendicular to each other.

[0019] In capacitor module 1, capacitor elements 10a, 10b, and 10c are capacitor elements with the same structure. Hereafter, capacitor elements 10a, 10b, and 10c may be collectively referred to as capacitor element 10.

[0020] Figure 4 is a schematic diagram showing an example of a capacitor element shown in Figure 2 in a perspective view. Figure 5 is a schematic diagram showing an example of a capacitor element shown in Figure 4 in a cross-sectional view along the line segment a1-a2.

[0021] The capacitor element 10 shown in Figures 4 and 5 comprises a base body 11, a first external electrode 12a, and a second external electrode 12b.

[0022] The base body 11 is a wound body formed by winding a first metallized film 13a and a second metallized film 13b in a state where they are stacked in a first direction D1. In other words, the capacitor element 10 is a wound-type film capacitor in which metallized films are stacked and wound.

[0023] The capacitor element 10 may also be a laminated film capacitor (for example, in the shape of a rectangular parallelepiped) in which metallized films are stacked.

[0024] The base body 11 has a first end face 11a and a second end face 11b that are opposite to the third direction D3.

[0025] The base body 11 has a side surface 11c that extends in a third direction D3 so as to connect the periphery of the first end surface 11a and the second end surface 11b.

[0026] In the capacitor element 10, from the viewpoint of reducing the height, it is preferable that the cross-sectional shape of the base body 11 is flattened when viewed in a cross-section perpendicular to the winding axis direction (third direction D3 in Figures 4 and 5). Specifically, it is preferable that the cross-sectional shape of the base body 11 is pressed into a flattened shape such as an ellipse or oblong, and that the thickness is smaller than when the cross-sectional shape of the base body 11 is a perfect circle.

[0027] Whether the base material was pressed to have a flattened cross-sectional shape can be confirmed, for example, by checking for the presence of press marks on the base material.

[0028] The capacitor element 10 may have a cylindrical winding shaft. The winding shaft is positioned on the central axis of the first metallized film 13a and the second metallized film 13b in the wound state, and serves as the winding shaft when winding the first metallized film 13a and the second metallized film 13b.

[0029] The first metallized film 13a comprises a first dielectric film 14a and a first metal layer 15a.

[0030] The first dielectric film 14a has a first main surface 14aa and a second main surface 14ab that are opposite to the first direction D1.

[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 such that, in the third direction D3, it reaches one side edge of the first dielectric film 14a but does not reach the other side edge of the first dielectric film 14a.

[0032] The second metallized film 13b comprises a second dielectric film 14b and a second metal layer 15b.

[0033] The second dielectric film 14b has a first main surface 14ba and a second main surface 14bb that are opposite to the first direction D1.

[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 such that, in the third direction D3, it does not reach one side edge of the second dielectric film 14b but reaches the other side edge of the second dielectric film 14b.

[0035] In the base body 11, the adjacent first metallized film 13a and second metallized film 13b are shifted in the third direction D3 such that the end of the first metal layer 15a that reaches the side edge of the first dielectric film 14a is exposed on the first end face 11a of the base body 11, and the end of the second metal layer 15b that reaches the side edge of the second dielectric film 14b is exposed on the second end face 11b of the base body 11. In other words, in the adjacent first metallized film 13a and second metallized film 13b, the first metallized film 13a protrudes toward the first external electrode 12a side relative to the second metallized film 13b. Also, in the adjacent first metallized film 13a and second metallized film 13b, the second metallized film 13b protrudes toward the second external electrode 12b side relative to the first metallized film 13a. In this state, the first metal layer 15a is connected to the first external electrode 12a but not to the second external electrode 12b. Also, the second metal layer 15b is connected to the second external electrode 12b but not to the first external electrode 12a.

[0036] In the base body 11, as described above, the adjacent first metallized film 13a and second metallized film 13b are shifted in the third direction D3. Therefore, in the adjacent first dielectric film 14a and second dielectric film 14b, the first dielectric film 14a, on which the first metal layer 15a is provided on the first main surface 14aa, protrudes toward the first external electrode 12a side relative to the second dielectric film 14b, on which the first metal layer 15a is not provided on the main surface. Also, in the adjacent first dielectric film 14a and second dielectric film 14b, the second dielectric film 14b, on which the second metal layer 15b is provided on the first main surface 14ba, protrudes toward the second external electrode 12b side relative to the first dielectric film 14a, on which the second metal layer 15b is not provided on the main surface.

[0037] Since the base material 11 is wound with the first metallized film 13a and the second metallized film 13b stacked in a first direction D1, it can be said that it contains the first dielectric film 14a, the first metal layer 15a, the second dielectric film 14b, and the second metal layer 15b in the first direction D1 in that order. Alternatively, the base material 11 can be said to be a wound body in which the first dielectric film 14a, the first metal layer 15a, the second dielectric film 14b, and the second metal layer 15b are wound with the first dielectric film 14a, the first metal layer 15a, the second dielectric film 14b, and the second metal layer 15b stacked in the first direction D1 in that order.

[0038] In the base material 11, the first main surface 14aa of the first dielectric film 14a and the second main surface 14bb of the second dielectric film 14b face each other in the first direction D1, and the second main surface 14ab of the first dielectric film 14a and the first main surface 14ba of the second dielectric film 14b face each other in the first direction D1. Thus, in the base material 11, the first metallized film 13a and the second metallized film 13b are wound in a state where they are stacked in the first direction D1. In other words, in the base material 11, the second metallized film 13b is on the inside of the first metallized film 13a, specifically, the first metal layer 15a is on the inside of the first dielectric film 14a, and the second metal layer 15b is on the inside of the second dielectric film 14b, so the first metallized film 13a and the second metallized film 13b are wound in a state where they are stacked in the first direction D1. In other words, in the base body 11, the first metal layer 15a and the second metal layer 15b face each other with the first dielectric film 14a or the second dielectric film 14b in between.

[0039] A fuse portion may be provided in the first metal layer 15a. The fuse portion provided in the first metal layer 15a is, for example, a portion that connects a divided electrode portion, which is a portion of the first metal layer 15a that is divided into multiple parts, with an electrode portion that is not facing the second metal layer 15b. Examples of electrode patterns for the first metal layer 15a provided with the fuse portion include the electrode patterns disclosed in Japanese Patent Application Publication No. 2004-363431 and Japanese Patent Application Publication No. Hei 5-251266.

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

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

[0042] In this specification, the main component means the component with the highest weight percentage, and preferably means the component with a weight percentage higher than 50% by weight.

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

[0044] In this specification, the thermosetting resin means a resin that can be cured by heat, but does not limit its curing method. Therefore, the thermosetting resin includes resins that can be cured by methods other than heat (for example, light, electron beam, etc.) as long as they are resins that can be cured by heat. Also, depending on the material, the reaction may start due to the reactivity of the material itself, and resins that can proceed with curing without necessarily applying heat or the like from the outside are also regarded as thermosetting resins. The same applies to photocurable resins, and resins that can be cured by methods other than light (for example, heat, etc.) are also included as long as they are resins that can be cured by light.

[0045] The curable resin preferably consists of 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 consists of a cured product having a urethane bond obtained by the reaction of the hydroxyl group of the first organic material and the isocyanate group of the second organic material.

[0046] The presence of a urethane bond in the dielectric film can be confirmed by analyzing it with a Fourier transform infrared spectrometer (FT-IR).

[0047] When the curable resin is obtained by the above-described reaction, an uncured portion 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 one of a hydroxyl group and 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 FT-IR.

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

[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 of these polyisocyanates and its modified product 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, polyether sulfone resin, polyether imide resin, polyarylate resin, and the like.

[0055] The first dielectric film 14a may contain an additive for adding various functions.

[0056] Examples of the additive include 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 a part of the crosslinked structure of the cured product. Examples of such an additive include a resin 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] The second dielectric film 14b, like the first dielectric film 14a, may contain a thermosetting resin as its main component, a photocurable resin as its main component, or a thermoplastic resin as its main component. Furthermore, the second dielectric film 14b, like the first dielectric film 14a, may also contain additives.

[0059] The compositions of the first dielectric film 14a and the second dielectric film 14b may be different from each other, but it is preferable that they be the same.

[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, but it is preferable that they be 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 preferably each produced by forming a resin solution containing the resin material described above into a film, and then curing it by heat treatment.

[0064] Examples of constituent materials for 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 it is preferable that they be 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 thicknesses of the first metal layer 15a and the second metal layer 15b may be different, but it is preferable that they be the same.

[0068] 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).

[0069] The first metal layer 15a and the second metal layer 15b are preferably formed by depositing the above-described metal onto the main surfaces of the first dielectric film 14a and the second dielectric film 14b, respectively.

[0070] Although the above describes an embodiment in which the base body 11 includes two metallized films, the base body 11 may include only one metallized film. For example, the base body 11 may include a metallized film having a first dielectric film 14a on which a first metal layer 15a is provided on a first main surface 14aa and a second metal layer 15b is provided on a second main surface 14ab, and a second dielectric film 14b without a metal layer. Alternatively, the base body 11 may include a metallized film having a second dielectric film 14b on which a first metal layer 15a is provided on a second main surface 14bb and a second metal layer 15b is provided on a first main surface 14ba, and a first dielectric film 14a without a metal layer.

[0071] The first external electrode 12a is provided on the surface of the base body 11. In the example shown in Figures 4 and 5, the first external electrode 12a is provided on the first end face 11a of the base 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 on the first end face 11a of the base 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 on the surface of the base body 11 at a position away from the first external electrode 12a. In the example shown in Figures 4 and 5, the second external electrode 12b is provided on the second end face 11b of the base 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 on the second end face 11b of the base 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 opposite polarities. For example, the first external electrode 12a may be the positive electrode and the second external electrode 12b may be the negative electrode, or the first external electrode 12a may be the negative electrode and the second external electrode 12b may be the positive electrode.

[0074] Examples of materials that make up the first external electrode 12a and the second external electrode 12b include metals such as zinc, aluminum, tin, and zinc-aluminum alloys.

[0075] The compositions of the first external electrode 12a and the second external electrode 12b may be different from each other, but it is preferable that they be the same.

[0076] The first external electrode 12a and the second external electrode 12b are preferably formed by thermal spraying the above-described metal onto the first end face 11a and the second end face 11b of the base body 11, respectively.

[0077] As shown in Figures 2 and 3, the capacitor elements 10a, 10b, and 10c are arranged so that the first external electrodes 12a face each other, or the second external electrodes 12b face each other. The capacitor elements 10a, 10b, and 10c may also be arranged so that the first external electrode 12a and the second external electrode 12b face each other.

[0078] The capacitor module 1 includes three capacitor elements 10a, 10b, and 10c, but the capacitor element 10 may be one, two, or four or more.

[0079] In capacitor module 1, the three capacitor elements 10a, 10b, and 10c have their external electrodes facing each other. When the capacitor module of the present invention comprises multiple capacitor elements, it is preferable that the multiple capacitor elements include at least two adjacent capacitor elements whose external electrodes face each other. When the capacitor module of the present invention comprises three or more capacitor elements, it is preferable that all capacitor elements are adjacent to each other with their external electrodes facing each other, but it is sufficient that the external electrodes of at least two adjacent capacitor elements face each other. Furthermore, the side surface 11c of a capacitor element may face the side surface 11c of another capacitor element in the second direction D2.

[0080] As shown in Figures 2 and 3, the busbar 20a for connecting the first element is electrically connected to the first external electrode 12a.

[0081] The busbar 20a for connecting the first element has two openings 21a and covers the entire first external electrode 12a except for the portion that overlaps with the openings 21a.

[0082] The capacitor module of the present invention has an element connection busbar with an opening that covers the entire external electrode except for the portion overlapping the opening, thus preventing the occurrence of cracks inside the external electrode of the capacitor element. In conventional capacitor modules, when a rapid temperature change is applied, stress is easily applied to the external electrode, which is mostly in direct contact with the encapsulant, due to the difference in thermal expansion coefficients between the capacitor element and the encapsulant. Since the strength of the external electrode is less than the adhesive strength between the encapsulant and the external electrode, cracks occur inside the external electrode, which has low strength, in the structure of conventional capacitor modules. In the present invention, the element connection busbar covers most of the external electrode, reducing the contact area between the encapsulant and the external electrode. Therefore, the stress generated by the difference in thermal expansion coefficients between the capacitor element and the encapsulant is more likely to be applied to the element connection busbar, which is in contact with the encapsulant, rather than to the external electrode, which has a reduced contact area with the encapsulant. Since the adhesive strength between the encapsulant and the element connection busbar is less than the strength of the external electrode, delamination occurs between the encapsulant and the element connection busbar due to the above-mentioned stress. As a result, the capacitor module of the present invention reduces the stress applied to the external electrodes, thereby preventing the occurrence of cracks inside the external electrodes.

[0083] The busbar 20a for connecting the first element preferably covers 60% or more of the first external electrode 12a, more preferably 90% or more, even more preferably 95% or more, and particularly preferably 98% or more.

[0084] The busbar 20a for connecting the first element may cover the central part of the first external electrode 12a, or the peripheral part, or both the central part and the peripheral part.

[0085] The first element connection busbar 20a is a plate-shaped member and has a first main surface 20aa and a second main surface 20ab that are opposite each other in the thickness direction (third direction D3 in Figure 2, etc.). The outer shape of the first element connection busbar 20a is substantially elliptical, the same as the first external electrode 12a. The outer shape of the first element connection busbar 20a is not particularly limited.

[0086] The busbar 20a for connecting the first element has its second main surface 20ab side in contact with the first external electrode 12a, and its first main surface 20aa side in contact with the sealing material 50 (not shown).

[0087] The busbar 20a for connecting the first element has a U-shaped opening 21a when viewed from the thickness direction (third direction D3 in Figure 2). The outer shape of the opening 21a, excluding the protruding portion 22a described later, is a rectangle with the side in the first direction D1 being longer.

[0088] However, the shape of the opening 21a is not particularly limited. For example, when viewed excluding the protruding portion 22a, it may be circular, triangular, square, or the like.

[0089] The number of openings 21a may be one or three or more, but as the number of openings 21a increases, the area covered by the first element connecting busbar 20a to the first external electrode 12a decreases, so it is preferable that the number of openings 21a be two or less.

[0090] If there are two or more openings 21a, the shapes of the openings 21a may be the same or different.

[0091] If there are two or more openings 21a, the areas of each opening 21a may be the same or different.

[0092] The total area of ​​the opening 21a is preferably 0.5% to 40% of the area of ​​the first external electrode 12a, and more preferably 1% to 10% of the area.

[0093] The shape of the protrusion 22a is a pin shape extending in the first direction D1. The busbar 20a for connecting the first element may be connected to the first external electrode 12a at the protrusion 22a via a joining member such as solder, or it may be welded. In this case, the connection or welding can be performed along the protrusion 22a.

[0094] The shape of the protrusion 22a is not particularly limited, as long as it can be connected to or welded to the first external electrode 12a. The protrusion 22a may or may not be provided in all openings 21a.

[0095] The first element connection busbar 20a has pin-shaped connection terminals 23a that connect to the first external connection busbar 30a. The connection terminals 23a extend in a first direction D1 from the outer edge of the first element connection busbar 20a toward the first external connection busbar 30a. The first element connection busbar 20a has two connection terminals 23a, but it may have one connection terminal 23a or three or more.

[0096] As shown in Figures 2 and 3, the busbar 20b for connecting the second element is electrically connected to the second external electrode 12b.

[0097] Since the busbar 20b for connecting the second element is electrically connected to the second external electrode 12b and not the first external electrode 12a, it has a different polarity from the busbar 20a for connecting the first element, which is electrically connected to the first external electrode 12a.

[0098] The busbar 20b for connecting the second element has two openings 21b and covers the entire second external electrode 12b except for the portion that overlaps with the openings 21b.

[0099] The busbar 20b for connecting the second element preferably covers 60% or more of the second external electrode 12b, more preferably 90% or more, even more preferably 95% or more, and particularly preferably 98% or more.

[0100] The second element connecting busbar 20b is a plate-shaped member and has a first main surface 20ba and a second main surface 20bb that are opposite to each other in the thickness direction. The outer shape of the second element connecting busbar 20b is substantially elliptical, the same as that of the second external electrode 12b. The outer shape of the second element connecting busbar 20b is not particularly limited.

[0101] The busbar 20b for connecting the second element has its second main surface 20bb side covering the second external electrode 12b, and its first main surface 20ba side in contact with the sealing material 50 (not shown).

[0102] The busbar 20b for connecting the second element has a U-shaped opening 21b. The outer shape of the opening 21b, when viewed excluding the protruding portion 22b described later, is a rectangle with the longer side in the first direction D1.

[0103] However, the shape of the opening 21b is not particularly limited. For example, when viewed excluding the protruding portion 22b, it may be circular, triangular, square, or the like.

[0104] The number of openings 21b may be one or three or more, but as the number of openings 21b increases, the area covered by the second element connecting busbar 20b to the second external electrode 12b decreases, so it is preferable that the number of openings 21b be two or less.

[0105] If there are two or more openings 21b, the shapes of the openings 21b may be the same or different.

[0106] If there are two or more openings 21b, the areas of each opening 21b may be the same or different.

[0107] The total area of ​​the openings 21b is preferably 0.5% to 40% of the area of ​​the second external electrode 12b, and more preferably 1% to 10% of the area.

[0108] The shape of the protrusion 22b is a pin shape extending in the first direction D1. The busbar 20b for connecting the second element may be connected to the second external electrode 12b at the protrusion 22b via a joining member such as solder, or it may be welded. In this case, the connection or welding can be performed along the protrusion 22b.

[0109] The shape of the protrusion 22b is not particularly limited, as long as it can be connected to or welded to the second external electrode 12b. The protrusion 22b may or may not be provided in all openings 21b.

[0110] The second element connection busbar 20b has pin-shaped connection terminals 23b that connect to the second external connection busbar 30b. The connection terminals 23b extend in a first direction D1 from the outer edge of the second element connection busbar 20b toward the second external connection busbar 30b. The second element connection busbar 20b has two connection terminals 23b, but there may be one connection terminal 23b or three or more.

[0111] The shapes of the busbar 20a for connecting the first element and the busbar 20b for connecting the second element may be the same or different.

[0112] Examples of constituent materials for the first element connecting busbar 20a and the second element connecting busbar 20b include metals such as copper, oxygen-free copper, aluminum, and alloys containing at least one of these. In particular, the constituent materials for the first element connecting busbar 20a and the second element connecting busbar 20b are preferably copper, a copper alloy, or oxygen-free copper. When the constituent materials for the first element connecting busbar 20a and the second element connecting busbar 20b are copper-based materials, examples of oxygen-free copper (copper: 99.96% by weight or more), tough pitch copper (copper: 99.90% by weight or more), phosphorus-deoxidized copper (copper: 99.90% by weight or more, phosphorus: 0.015% by weight or more, 0.040% by weight or less) can be used.

[0113] The constituent materials of the first element connecting busbar 20a and the second element connecting busbar 20b may be the same or different.

[0114] The thicknesses of the first element connection busbar 20a and the second element connection busbar 20b may be the same or different.

[0115] Preferably, the first main surface 20aa of the first element connecting busbar 20a, which is the surface facing the sealing material 50, is coated with a non-adhesive substance. By coating the first main surface 20aa with a non-adhesive substance, the adhesive strength between the first element connecting busbar 20a and the sealing material 50 can be reduced. As a result, delamination between the sealing material 50 and the first element connecting busbar 20a becomes more likely, and the occurrence of cracks inside the first external electrode 12a can be more effectively prevented.

[0116] The busbar 20a for connecting the first element only needs to have at least the first main surface 20aa on the sealing material 50 side coated with a non-adhesive substance, and both the first main surface 20aa and the second main surface 20ab may be coated with a non-adhesive substance.

[0117] Preferably, the first main surface 20ba of the bus bar 20b for connecting the second element, which is the surface facing the sealing material 50, is coated with a non-adhesive substance. By coating the first main surface 20ba with a non-adhesive substance, the adhesive strength between the bus bar 20b for connecting the second element and the sealing material 50 can be reduced. As a result, delamination between the sealing material 50 and the bus bar 20b for connecting the second element becomes more likely, and the occurrence of cracks inside the second external electrode 12b can be more effectively prevented.

[0118] The busbar 20b for connecting the second element only needs to have at least the first main surface 20ba on the sealing material 50 side coated with a non-adhesive substance, and both the first main surface 20ba and the second main surface 20bb may be coated with a non-adhesive substance.

[0119] Examples of non-adhesive materials include fluoropolymer films.

[0120] The busbars 20a for connecting the first element and 20b for connecting the second element may be coated with a tin plating film instead of a non-adhesive material. The tin plating film provides the same effect as coating with a non-adhesive material.

[0121] The busbar 20a for connecting the first element is formed using copper or a copper alloy as a base material, and it is preferable that the first main surface 20aa, which is the surface facing the sealing material 50, is coated with a tin plating film or a fluororesin film. The busbar 20a for connecting the first element only needs to have at least the first main surface 20aa facing the sealing material 50 coated with a tin plating film or a fluororesin film, and both the first main surface 20aa and the second main surface 20ab may be coated with a tin plating film or a fluororesin film.

[0122] The busbar 20b for connecting the second element is formed using copper or a copper alloy as a base material, and it is preferable that the first main surface 20ba, which is the surface facing the sealing material 50, is coated with a tin plating film or a fluororesin film. The busbar 20b for connecting the second element only needs to have at least the first main surface 20ba facing the sealing material 50 coated with a tin plating film or a fluororesin film, and both the first main surface 20ba and the second main surface 20bb may be coated with a tin plating film or a fluororesin film.

[0123] As shown in Figures 2 and 3, in the capacitor module 1, one first element connection busbar 20a or one second element connection busbar 20b is in contact with one first external electrode 12a or one second external electrode 12b. When two external electrodes of the same polarity face each other, one element connection busbar may branch into two, each covering one of the two external electrodes.

[0124] As shown in Figures 2 and 3, the first external connection busbar 30a has an external connection terminal 31a on the opposite side from the capacitor elements 10a, 10b, and 10c, and is electrically connected to the first external electrode 12a via the first element connection busbar 20a.

[0125] The first external connection busbar 30a faces the surface of the capacitor elements 10a, 10b, and 10c where the first external electrodes 12a and the second external electrodes 12b are not provided. In the example shown in Figures 2 and 3, the first external connection busbar 30a faces the side surface 11c of the base body 11, which is the surface where the first external electrodes 12a and the second external electrodes 12b of the capacitor elements 10a, 10b, and 10c are not provided.

[0126] As shown in Figure 1, the first external connection busbar 30a has an external connection terminal 31a that extends outside the sealing material 50. The external connection terminal 31a is used to electrically connect the capacitor module 1 to an external circuit board, device, etc.

[0127] As shown in Figures 1, 2, and 3, the external connection terminal 31a has a circular through-hole at its tip. The external connection terminal 31a does not necessarily have to have a through-hole.

[0128] As shown in Figures 2 and 3, the outer edge shape of the main body portion 32a of the first external connection busbar 30a, excluding the external connection terminal 31a, is rectangular when viewed from the first direction D1. The outer edge shape of the main body portion 32a is not limited to a rectangle, and may be elliptical, T-shaped, L-shaped, etc.

[0129] The first external connection busbar 30a is a plate-shaped member and has a first main surface 30aa and a second main surface 30ab that are opposite each other in the thickness direction (first direction D1 in Figure 3, etc.).

[0130] The first external connection busbar 30a has window portions 32aa and 32ab inside the main body portion 32a. Window portion 32aa overlaps the position where both second external electrodes 12b of capacitor elements 10a and 10b face each other when viewed from the first direction D1. Window portion 32ab overlaps the position where both first external electrodes 12a of capacitor elements 10b and 10c face each other when viewed from the first direction D1.

[0131] The window section 32ab is provided with a connecting section 33a. The connecting section 33a is connected to the main body section 32a via two bridge sections 35a.

[0132] As shown in Figures 2 and 3, the first external connection busbar 30a and the second external connection busbar 30b overlap.

[0133] In the capacitor module 1, as shown in Figures 2 and 3, the first external connection busbar 30a overlaps the second external connection busbar 30b, so the position of the main body 32a in the first direction D1 is far from the position of the connection terminal 23a of the first element connection busbar 20a in the first direction D1. The bridge portion 35a is bent from the main body 32a toward the capacitor elements 10b and 10c, so that the position of the connection portion 33a in the first direction D1 is aligned with the position of the connection terminal 23a.

[0134] The connection portion 33a has a penetration hole 34a into which the connection terminal 23a of the first element connection busbar 20a is inserted.

[0135] The main body portion 32a of the first external connection busbar 30a is also provided with a connection portion 33a via a bridge portion 35a at the position of the first element connection busbar 20a that covers the first external electrode 12a of the capacitor element 10a when viewed from the first direction D1.

[0136] The three first element connection busbars 20a and the first external connection busbar 30a are connected by a connection portion 33a. The first external connection busbar 30a is electrically connected to the first external electrodes 12a of the capacitor elements 10a, 10b, and 10c via the first element connection busbars 20a.

[0137] As shown in Figures 2 and 3, the second external connection busbar 30b has an external connection terminal 31b on the opposite side of the capacitor elements 10a, 10b, and 10c, and is electrically connected to the second external electrode 12b via the second element connection busbar 20b.

[0138] The second external connection busbar 30b faces the surface of the capacitor elements 10a, 10b, and 10c where the first external electrodes 12a and the second external electrodes 12b are not provided. In the example shown in Figures 2 and 3, the second external connection busbar 30b faces the side surface 11c of the base body 11, which is the surface where the first external electrodes 12a and the second external electrodes 12b of the capacitor elements 10a, 10b, and 10c are not provided.

[0139] As shown in Figure 1, the second external connection busbar 30b has an external connection terminal 31b that is brought out to the outside of the sealing material 50. The external connection terminal 31b is used to electrically connect the capacitor module 1 to an external circuit board, device, etc.

[0140] As shown in Figures 1, 2, and 3, the external connection terminal 31b has a circular through-hole at its tip. The external connection terminal 31b does not necessarily have to have a through-hole.

[0141] As shown in Figure 3, the second external connection busbar 30b has a rectangular shape in its main body portion 32b, excluding the external connection terminal 31b, when viewed from the first direction D1. The shape of the main body portion 32b is not limited to a rectangle; it may be elliptical, T-shaped, L-shaped, or the like.

[0142] The second external connection busbar 30b is a plate-shaped member and has a first main surface 30ba and a second main surface 30bb that are opposite to each other in the thickness direction.

[0143] The second external connection busbar 30b has window portions 32ba and 32bb inside the main body portion 32b. Window portion 32ba overlaps the position where both second external electrodes 12b of capacitor elements 10a and 10b face each other when viewed from the first direction D1. Window portion 32bb overlaps the position where both first external electrodes 12a of capacitor elements 10b and 10c face each other when viewed from the first direction D1.

[0144] The window portion 32ba is provided with a connecting portion 33b. The connecting portion 33b is connected to the main body portion 32b via two bridge portions 35b.

[0145] The connection portion 33b has a penetration hole 34b into which the connection terminal 23b of the bus bar 20b for connecting the second element is inserted.

[0146] The main body portion 32b of the second external connection bus bar 30b is also provided with a connection portion 33b via a bridge portion 35b at the position of the second element connection bus bar 20b that covers the second external electrode 12b of the capacitor element 10c when viewed from the first direction D1.

[0147] The three second element connection busbars 20b and the second external connection busbar 30b are connected at a connection point 33b. The second external connection busbar 30b is electrically connected to the second external electrodes 12b of the capacitor elements 10a, 10b, and 10c via the second element connection busbars 20b.

[0148] The shapes of the first external connection busbar 30a and the second external connection busbar 30b may be the same or different.

[0149] Examples of constituent materials for the first external connection busbar 30a and the second external connection busbar 30b include those exemplified as constituent materials for the first element connection busbar 20a and the second element connection busbar 20b.

[0150] The constituent materials of the first external connection busbar 30a and the second external connection busbar 30b may be the same or different.

[0151] As described above, the first external connection busbar 30a and the second external connection busbar 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 external connection busbar 30a becomes a busbar for the positive electrode and the second external connection busbar 30b becomes a busbar 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 external connection busbar 30a becomes a busbar for the negative electrode and the second external connection busbar 30b becomes a busbar for the positive electrode.

[0152] The first external connection busbar 30a has its second main surface 30ab facing the first main surface 30ba of the second external connection busbar 30b. When parts of the first external connection busbar 30a and the second external connection busbar 30b are close together and overlapping, specifically when a predetermined gap is provided between the first external connection busbar 30a and the second external connection busbar 30b, it is preferable that an insulating sheet 40, which forms a laminated structure together with the first external connection busbar 30a and the second external connection busbar 30b, is sandwiched between the first external connection busbar 30a and the second external connection busbar 30b, as shown in Figures 2 and 3. Specifically, it is preferable that the first external connection busbar 30a, the insulating sheet 40, and the second external connection busbar 30b are stacked in that order to form a laminated structure. In this case, the insulating sheet 40 ensures insulation between the first external connection busbar 30a and the second external connection busbar 30b.

[0153] As shown in Figures 2 and 3, the outer edge shape of the insulating sheet 40 is a rectangle slightly larger than the outer edge shape of the main body portion 32a of the first external connection busbar 30a and the outer edge shape of the main body portion 32b of the second external connection busbar 30b. The insulating sheet 40 has insulating sheet windows 40a and 40b at positions that overlap with the windows 32aa and 32ab of the first external connection busbar 30a and the windows 32ba and 32bb of the second external connection busbar 30b when viewed from the first direction D1. The shape of the insulating sheet 40 is not particularly limited as long as the first external connection busbar 30a and the second external connection busbar 30b do not come into contact with each other. For example, the shape of the insulating sheet 40 may be the same as that of one of the external connection busbars.

[0154] In this specification, the insulating sheet 40 also includes forms such as insulating paper, insulating board, and insulating film.

[0155] Examples of materials that make up the insulating sheet 40 include resin.

[0156] As shown in Figure 1, the sealing material 50 seals the capacitor elements 10a, 10b, 10c, the first element connection busbar 20a, the second element connection busbar 20b, the first external connection busbar 30a, and the second external connection busbar 30b so that the external connection terminals 31a, 31b are exposed to the outside. Because the capacitor elements 10a, 10b, and 10c are sealed with the sealing material 50 in this way, the intrusion of moisture and other elements can be suppressed.

[0157] As the sealing material 50, it is preferable to appropriately select a resin with low moisture permeability from the viewpoint of suppressing the penetration of moisture into the capacitor elements 10a, 10b, and 10c. Examples include epoxy resin, silicone resin, and urethane resin. Examples of curing agents for epoxy resin include amine curing agents and imidazole curing agents.

[0158] As the sealing material 50, only the resin described above may be used, but a resin to which a reinforcing agent has been added may also be used for the purpose of improving strength. Examples of reinforcing agents include silica and alumina.

[0159] From the viewpoint of suppressing the intrusion of moisture into the capacitor elements 10a, 10b, and 10c, it is preferable that the thickness of the sealing material 50 over the capacitor elements 10a, 10b, and 10c be greater on the side where the first external connection busbar 30a and the second external connection busbar 30b face each other.

[0160] The thickness of the sealing material 50 is measured, for example, using a soft X-ray device in a non-destructive state, and using a length measuring device such as a caliper in a destructive state.

[0161] Figure 6 is a schematic diagram showing the stress state of the capacitor element shown in Figure 2. Figure 7 is a schematic diagram showing an example of the structure shown in Figure 2 as viewed along the line segment b1-b2.

[0162] In the capacitor module of the present invention, the busbar for element connection covers the external electrodes, and the stress generated by the difference in thermal expansion coefficients between the capacitor element and the sealing material due to temperature changes causes delamination between the sealing material and the busbar for element connection, thereby reducing the stress applied to the external electrodes. On the other hand, as shown in Figure 6, the second busbar for element connection 20b has an opening 21b, and the second external electrode 12b of the capacitor element 10a (not shown) is exposed through the opening 21b, so a considerable amount of the above stress can be applied to the exposed second external electrode 12b.

[0163] In contrast, in the capacitor module of the present invention, when viewed from a direction in which the external electrodes of one capacitor element and the external electrodes of the other capacitor element face each other, it is preferable that the portions of each external electrode exposed from the opening are offset from each other. In the capacitor module 1, as shown in Figure 7, when viewed from a direction in which the second external electrode 12b of capacitor element 10a and the second external electrode 12b of capacitor element 10b face each other, it is preferable that the portions of the second external electrode 12b of capacitor element 10a and the second external electrode 12b of capacitor element 10b that are exposed from the opening 21b are offset from each other. In Figure 7, the portion of the second external electrode 12b of capacitor element 10a exposed from the opening 21b and the portion of the second external electrode 12b of capacitor element 10b exposed from the opening 21b are offset in the second direction D2, but they may also be offset in the first direction D1, or offset in both the first direction D1 and the second direction D2. When the portions of the opposing external electrodes that are exposed from the opening of the element connection busbar are misaligned, the stress generated is more likely to be applied to the element connection busbar opposite the exposed external electrode, rather than to the exposed external electrode itself. As a result, this stress makes it easier for delamination to occur between the element connection busbar opposite the exposed external electrode and the sealing material. Consequently, the stress applied to the inside of the exposed external electrode is reduced, and as a result, the occurrence of cracks inside the external electrode can be more effectively prevented.

[0164] The following describes another example of the capacitor module of the present invention.

[0165] Figure 8 is a schematic diagram showing another example of the capacitor module of the present invention in a perspective view. Figure 9 is a schematic diagram showing an example of the capacitor module shown in Figure 8 (excluding the encapsulating material) in a disassembled state.

[0166] The capacitor module 2 shown in Figures 8 and 9 further comprises an outer case 60 in which the capacitor module 1 is housed. Specifically, the capacitor module 2 further comprises an outer case 60 in which capacitor elements 10a, 10b, 10c, a bus bar 20a for connecting the first element, a bus bar 20b for connecting the second element, a bus bar 30a for connecting the first external connection, a bus bar 30b for connecting the second external connection, and a sealing material 50 are housed, such that external connection terminals 31a and 31b are brought out to the outside.

[0167] As shown in Figures 8 and 9, the outer casing 60 is a bottomed cylindrical shape with a case opening 61. Specifically, the outer casing 60 is a bottomed cylindrical shape with a case opening 61 at one end in the first direction D1.

[0168] In the example shown in Figures 8 and 9, the outer case 60 has a case bottom wall portion 62 facing the case opening 61, and a case side wall portion 63 extending from the case bottom wall portion 62 toward the case opening 61.

[0169] It is preferable that the capacitor elements 10a, 10b, and 10c are housed inside the outer casing 60 so as to be separated from the inner surface of the outer casing 60.

[0170] It is preferable that the first external electrode 12a and the second external electrode 12b face the case side wall 63. It is preferable that the first external electrode 12a and the second external electrode 12b do not face the case bottom wall 62.

[0171] Examples of the outer casing 60 include resin cases, metal cases, and the like.

[0172] When the outer casing 60 is a resin case, examples of resins that make up the resin case include liquid crystal polymer (LCP), polyphenylene sulfide resin, and polybutylene terephthalate resin. Among these, it is preferable that the resin case contains liquid crystal polymer.

[0173] As the liquid crystal polymer contained in the resin case, for example, a liquid crystal polymer having p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid groups in its backbone can be used. In addition to p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid groups, liquid crystal polymers formed by polycondensation using various components such as phenol, phthalic acid, and ethylene terephthalate can also be used. Furthermore, when classifying liquid crystal polymers, there are classification methods such as Type I, Type II, and Type III, but in terms of materials, these refer to the same materials as the liquid crystal polymer formed from the above-mentioned components.

[0174] The resin case preferably further contains an inorganic filler in addition to the liquid crystal polymer.

[0175] As the inorganic filler included in the resin case, a material with higher strength than the liquid crystal polymer can be used. Preferably, the inorganic filler is 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.

[0176] The form of the inorganic filler is not particularly limited, and examples include forms having a longitudinal direction, such as fibrous or plate-like forms. Multiple types of inorganic materials may be used in combination as such inorganic fillers. Preferably, the resin case contains at least one of a fibrous inorganic material and a plate-like inorganic material as the inorganic filler.

[0177] In this specification, a filler is described as fibrous if the relationship between the longitudinal dimension in the longitudinal direction and the cross-sectional diameter in a section perpendicular to the longitudinal direction is such that longitudinal dimension / cross-sectional diameter ≥ 5 (i.e., an aspect ratio of 5:1 or greater). Here, the cross-sectional diameter is defined as the distance between the two longest points on the outer circumference of the cross-section. If the cross-sectional diameter differs in the longitudinal direction, the measurement is taken at the point where the cross-sectional diameter is maximum.

[0178] In this specification, "filler is plate-shaped" means that in the filler, 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 such that cross-sectional diameter / maximum height ≥ 3.

[0179] Preferably, the inorganic filler has at least a portion of it that is oriented in the direction from the case bottom wall 62 towards the case opening 61 on the case side wall 63, and a portion that is oriented in the direction of the outer circumference of the case side wall 63, and is dispersed inside the outer case 60.

[0180] The inorganic filler material is preferably 5 μm or larger in diameter and 50 μm or larger in length.

[0181] It is preferable that the inorganic filler is dispersed throughout the outer casing 60 without agglomerating.

[0182] Examples of inorganic fillers include fibrous glass fillers, plate-shaped talc, or mica. Among these, it is preferable that the inorganic filler mainly contains fibrous glass fillers.

[0183] 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 the inorganic filler described above.

[0184] The resin case is manufactured, for example, by methods such as injection molding.

[0185] If the outer casing 60 is a metal case, examples of metals that make up the metal case include individual metals such as aluminum, magnesium, iron, stainless steel, and copper, as well as alloys containing at least one of these individual metals. In particular, it is preferable that the metal case contains aluminum or an aluminum alloy.

[0186] The metal case is manufactured, for example, by a method such as impact molding.

[0187] When the capacitor element 10 is housed inside the outer case 60 such that it is separated from the inner surface of the outer case 60, it is preferable that the sealing material 50 is filled between the capacitor element 10 and the outer case 60, specifically between the outer surface of the capacitor element 10 and the inner surface of the outer case 60. Furthermore, it is preferable that the sealing material 50 is filled not only between the capacitor element 10 and the outer case 60, but also in the area extending from the case opening 61 to the capacitor element 10 inside the outer case 60.

[0188] From the viewpoint of suppressing the intrusion of moisture into the capacitor element 10, it is preferable that the thickness of the sealing material 50 at the case opening 61 be large. The thickness of the sealing material 50 at the case opening 61 is preferably sufficiently large within the allowable range of the overall volume (size) of the capacitor module 2, specifically, it is preferably 2 mm or more, and more preferably 4 mm or more. In particular, it is preferable to arrange the capacitor element 10 inside the outer case 60 on the case bottom wall portion 62 side rather than on the case opening 61 side, thereby making the thickness of the sealing material 50 relative to the capacitor element 10 larger on the case opening 61 side than on the case bottom wall portion 62 side.

[0189] As shown in Figure 9, the outer edges of the first element connecting busbar 20a and the second element connecting busbar 20b are provided with protrusions 24a and 24b, respectively. The inner surface of the case side wall portion 63 of the outer case 60 is provided with recesses 64 that fit with the protrusions 24a and 24b. The recesses 64 are provided by forming grooves in a fitting portion 65 provided on the inner surface of the case side wall portion 63.

[0190] When inserting a capacitor module, which has a configuration in which capacitor elements, external connection busbars, and element connection busbars are electrically connected to each other, into an outer case, the outer edge of the element connection busbars fits with the inner surface of the outer case, making it easy to position the element connection busbars and to control the distance between capacitor elements and the distance between capacitor elements and the outer case. If the distance between capacitor elements and the distance between capacitor elements and the outer case can be controlled, the thickness of the sealing material between capacitor elements and between capacitor elements and the outer case can be adjusted, making it easier for delamination between the sealing material and the element connection busbars to occur, and thus better preventing the occurrence of cracks inside the external electrodes.

[0191] The relationship between the outer edge of the element connection busbar and the inner surface of the outer case may be reversed. For example, recesses may be provided on the outer edge of the first element connection busbar 20a and the outer edge of the second element connection busbar 20b, and protrusions that fit into the recesses may be provided on the inner surface of the case side wall portion 63 of the outer case 60.

[0192] In the capacitor module 2, instead of fitting together, the outer edge of the element connection busbar and the inner surface of the outer case may be locked together. For example, a pin may be provided on the outer edge of the element connection busbar, and a hole may be provided on the inner surface of the case side wall portion 63 of the outer case 60 for the pin to be locked into. Alternatively, for example, a protrusion may be provided on the outer edge of the element connection busbar, and a recess may be provided on the inner surface of the case side wall portion of the outer case for the protrusion to slide and be locked into.

[0193] This specification discloses the following:

[0194] <1> A capacitor module comprising: at least one capacitor element having an external electrode; an element connection busbar electrically connected to the external electrode; an external connection busbar having an external connection terminal on the opposite side of the capacitor element and electrically connected to the external electrode via the element connection busbar; and a sealing material that seals the capacitor element, the element connection busbar and the external connection busbar so that the external connection terminal is brought out to the outside, wherein the element connection busbar has an opening and covers the entire external electrode except for the portion that overlaps the opening.

[0195] <2> The capacitor module according to <1>, wherein at least the side of the busbar for connecting the element that is on the sealing material side is coated with a non-adhesive material.

[0196] <3> The capacitor module according to <1>, wherein the busbar for connecting the element is formed on a copper or copper alloy base material, and at least the surface on the sealing material side is coated with a tin plating film or a fluororesin film.

[0197] <4> The capacitor module according to any one of <1> to <3>, wherein the busbar for external connection is facing the surface of the capacitor element that does not have the external electrodes.

[0198] <5> The capacitor module according to any one of <1> to <4>, further comprising an outer case in which the capacitor element, the bus bar for connecting the element, the bus bar for external connection, and the sealing material are housed inside, such that the external connection terminal is brought out to the outside.

[0199] <6> The capacitor module according to <5>, wherein the outer casing is a bottomed cylindrical shape with a case opening, and has a case bottom wall portion facing the case opening and a case side wall portion extending from the case bottom wall portion toward the case opening, and the external electrodes are facing the case side wall portion.

[0200] <7> A capacitor module according to any one of <1> to <6>, comprising a plurality of the capacitor elements, wherein the plurality of capacitor elements include at least two adjacent capacitor elements such that their external electrodes face each other.

[0201] <8> The capacitor module according to <7>, wherein when viewed from a direction in which the external electrode of one capacitor element and the external electrode of the other capacitor element face each other, the portions of each external electrode exposed from the opening are offset from each other.

[0202] <9> The capacitor module described in <5> or <6>, wherein the busbar for connecting the element is fitted or locked to the inner surface of the outer casing.

[0203] <10> The capacitor module according to <9>, wherein one of the outer edge of the busbar for connecting the element and the inner surface of the outer case is provided with a recess, and the other is provided with a protrusion that fits into or locks into the recess.

[0204] <11> A capacitor module according to any of <1> to <10>, wherein the capacitor element is a film capacitor.

[0205] 1, 2 Capacitor module 10, 10a, 10b, 10c Capacitor element 11 Base body 11a First end face of base body 11b Second end face of base body 11c Side surface of base body 12a First external electrode 12b Second 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 First metal layer 15b Second metal layer 20a First element connection busbar 20aa First main surface of first element connection busbar 20ab Second main surface of first element connection busbar 20b Second element connection busbar 20ba 20bb First main surface of the second element connection busbar Second main surface of the second element connection busbar 21a Opening of the first element connection busbar 21b Opening of the second element connection busbar 22a Protruding part of the first element connection busbar 22b Protruding part of the second element connection busbar 23a Connection terminal of the first element connection busbar 23b Connection terminal of the second element connection busbar 24a Convex part of the first element connection busbar 24b Convex part of the second element connection busbar 30a First external connection busbar 30b Second external connection busbar 30aa First main surface of the first external connection busbar 30ab Second main surface of the first external connection busbar 30ba First main surface of the second external connection busbar 30bb Second main surface of the second external connection busbar 31a External connection terminal of the first external connection busbar 31b External connection terminal of the second external connection busbar 32a Main body of the first external connection busbar 32b Main body of the second external connection busbar 32aa, 32ab Window portion of the first external connection busbar 32ba, 32bb Window portion of the second external connection busbar 33a Connection portion of the first external connection busbar 33b Connection portion of the second external connection busbar 34a Penetration hole of the first external connection busbar 34b Penetration hole of the second external connection busbar 35a Bridge portion of the first external connection busbar 35b Bridge portion of the second external connection busbar 40 Insulating sheet 40a, 40b Insulating sheet window portion 50 Sealing material 60 Outer case 61 Case opening 62 Case bottom wall portion 63 Case side wall portion 64 Recess of the case side wall portion65 Fitting portion of the case side wall D1 First direction D2 Second direction D3 Third direction

Claims

1. A capacitor module comprising: at least one capacitor element having an external electrode; an element connection busbar electrically connected to the external electrode; an external connection busbar having an external connection terminal on the opposite side of the capacitor element and electrically connected to the external electrode via the element connection busbar; and a sealing material that seals the capacitor element, the element connection busbar and the external connection busbar so that the external connection terminal is brought out to the outside, wherein the element connection busbar has an opening and covers the entire external electrode except for the portion that overlaps the opening.

2. The capacitor module according to claim 1, wherein at least the surface of the busbar for connecting the element is coated with a non-adhesive material.

3. The capacitor module according to claim 1, wherein the busbar for connecting the element is formed from a copper or copper alloy base material, and at least the surface facing the sealing material is coated with a tin plating film or a fluororesin film.

4. The capacitor module according to any one of claims 1 to 3, wherein the external connection busbar is facing the surface of the capacitor element that does not have the external electrodes.

5. The capacitor module according to any one of claims 1 to 4, further comprising an outer case in which the capacitor element, the busbar for connecting the element, the busbar for external connection, and the sealing material are housed, such that the external connection terminal is brought out to the outside.

6. The capacitor module according to claim 5, wherein the outer casing is a bottomed cylindrical shape with a case opening, and has a case bottom wall portion facing the case opening and a case side wall portion extending from the case bottom wall portion toward the case opening, and the external electrodes are facing the case side wall portion.

7. A capacitor module according to any one of claims 1 to 6, comprising a plurality of capacitor elements, wherein the plurality of capacitor elements include at least two adjacent capacitor elements such that their external electrodes face each other.

8. The capacitor module according to claim 7, wherein, when viewed from a direction in which the external electrode of one capacitor element and the external electrode of the other capacitor element face each other, the portions of each external electrode exposed from the opening are offset from each other.

9. The capacitor module according to claim 5 or 6, wherein the busbar for connecting the element is fitted or locked to the inner surface of the outer casing.

10. The capacitor module according to claim 9, wherein one of the outer edge of the element connection busbar and the inner surface of the outer case is provided with a recess, and the other is provided with a protrusion that fits into or locks into the recess.

11. The capacitor module according to any one of claims 1 to 10, wherein the capacitor element is a film capacitor.

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