Capacitor module

Abstract

The present invention provides a capacitor module that can suppress the intrusion of moisture from the outside of the sealing resin into the capacitor element inside the sealing resin. [Solution] The capacitor module 1 has a first bus bar 20 which has a first terminal 21 located outside the sealing resin 60, a first main projection 22 which protrudes from the sealing resin toward the first terminal, and a first sub-projection 23 which protrudes from the sealing resin at a different position from the first main projection so as not to be toward the first terminal and has a projection length shorter than the first main projection. The second bus bar 30 has a second terminal 31 located outside the sealing resin, a second main projection 32 which protrudes from the sealing resin toward the second terminal, and a second sub-projection 33 which protrudes from the sealing resin at a different position from the second main projection so as not to be toward the second terminal and has a projection length shorter than the second main projection. The insulator 40 extends to cover the boundary P1 between the first sub-projection and the insulator when viewed from the direction in which the first bus bar protrudes from the sealing resin.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a capacitor including a capacitor element, a first electrode and a second electrode formed on both end faces of the capacitor element, a first bus bar connected to the first electrode, a second bus bar connected to the second electrode, a first region and a second region respectively included in the first bus bar and the second bus bar and facing each other, a first insulating member having insulating properties and interposed between the first region and the second region, and a metal case. The capacitor element, the first bus bar, the second bus bar and the first insulating member are integrally assembled to form a capacitor element unit, the capacitor element unit is housed in the case, the first insulating member is provided with a first mounting portion, and the case is provided with a second mounting portion to which the first mounting portion is attached so that the capacitor element unit is disposed at a predetermined position with respect to the case and the first bus bar and the second bus bar do not contact the case.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a capacitor module in which a capacitor element is housed inside a case and a sealing resin is filled inside the case so that the capacitor element is embedded, generally, a first busbar electrically connected to the first external electrode of the capacitor element and a second busbar electrically connected to the second external electrode of the capacitor element are drawn out from the inside to the outside of the sealing resin and electrically connected to the object to be connected, such as a circuit board or device. Furthermore, in order to ensure insulation between the first busbar and the second busbar (to prevent a short circuit between the first busbar and the second busbar), an insulator is sandwiched between the first busbar and the second busbar, and the insulator, along with the first busbar and the second busbar, is drawn out from the inside to the outside of the sealing resin.

[0005] However, in a capacitor module with the above configuration, moisture may penetrate from areas outside the sealing resin, such as the boundary between the first busbar and the insulator, and the boundary between the second busbar and the insulator. Moisture that penetrates from outside the sealing resin in this way may travel along these boundaries and penetrate into the capacitor elements inside the sealing resin. When moisture penetrates into the capacitor elements, the capacitor elements will absorb the moisture and expand, and the first busbar, second busbar, and insulator surrounding the capacitor elements will be pressed against the sealing resin by the expanded capacitor elements, which may cause the sealing resin to crack (for example, develop a fissure). When the sealing resin cracks, moisture can more easily penetrate into the capacitor elements from the sealing resin itself, which may lead to a deterioration in the electrical characteristics of the capacitor elements and thus reduce the reliability of the capacitor module.

[0006] As shown in Figure 1, the capacitor described in Patent Document 1 also has a first busbar, a second busbar, and an insulating plate (corresponding to an insulator) that are drawn out from the inside to the outside of the filling resin (corresponding to a sealing resin). Therefore, as mentioned above, there is a risk that moisture may penetrate into the capacitor elements located inside the filling resin, which may result in defects such as cracking of the filling resin.

[0007] The present invention has been made to solve the above problems and aims to provide a capacitor module that can suppress the intrusion of moisture from outside the sealing resin into the capacitor element inside the sealing resin. [Means for solving the problem]

[0008] The capacitor module of the present invention comprises a capacitor element having a first external electrode and a second external electrode; a first busbar electrically connected to the first external electrode; a second busbar electrically connected to the second external electrode; an insulator sandwiched between the first busbar and the second busbar so as to form a laminated structure together with the first busbar and the second busbar; a case in which the capacitor element is housed; and a sealing resin filled inside the case so as to embed the capacitor element and allow the first busbar, the second busbar, and the insulator to be drawn out from the inside to the outside, wherein the first busbar has a first terminal located outside the sealing resin and the sealing resin is directed toward the first terminal The second busbar has a first main projection that protrudes from the first terminal, and a first sub-projection that protrudes from the sealing resin at a position different from the first main projection so as not to face the first terminal, and the length of the projection from the sealing resin is shorter than that of the first main projection; the second busbar has a second terminal located outside the sealing resin, a second main projection that protrudes from the sealing resin so as to face the second terminal, and a second sub-projection that protrudes from the sealing resin at a position different from the second main projection so as not to face the second terminal, and the length of the projection from the sealing resin is shorter than that of the second main projection; and the insulator extends to cover the boundary between the first sub-projection and the insulator when viewed from the direction in which the first busbar protrudes from the sealing resin. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a capacitor module that can suppress the intrusion of moisture from the outside of the sealing resin into the capacitor element inside the sealing resin. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic perspective view showing an example of the capacitor module of the present invention. [Figure 2] Figure 2 is a schematic perspective view showing an example of the capacitor module in Figure 1 with the sealing resin removed. [Figure 3] Figure 3 is a schematic perspective view showing an example of the capacitor module in Figure 1 with the sealing resin and case removed. [Figure 4] Figure 4 is a schematic perspective view showing an example of the capacitor element in Figure 3. [Figure 5] Figure 5 is a schematic cross-sectional view showing an example of a cross-section along the line a1-a2 of the capacitor element in Figure 4. [Figure 6] Figure 6 is a schematic plan view showing an example of the capacitor module in Figure 1 as viewed from a first direction. [Figure 7] Figure 7 is a schematic cross-sectional view showing an example of a cross-section along the line A1-A2 of the capacitor module in Figure 6. [Figure 8] Figure 8 is a schematic cross-sectional view showing an example of a cross-section along the line B1-B2 of the capacitor module in Figure 6. [Figure 9] Figure 9 is a schematic perspective view showing another example of the capacitor module of the present invention. [Figure 10] Figure 10 is a schematic plan view showing an example of the capacitor module in Figure 9 as viewed from the first direction. [Figure 11] Figure 11 is a schematic cross-sectional view showing an example of a cross-section along the C1-C2 line of the capacitor module in Figure 10. [Modes for carrying out the invention]

[0011] 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.

[0012] The drawings shown below are schematic representations, and their dimensions, aspect ratios, and scales may differ from those of the actual product.

[0013] 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 the literal, exact form, but also a range that is substantially equivalent, for example, a range that includes differences of a few percent.

[0014] [Capacitor Module] The capacitor module of the present invention comprises a capacitor element having a first external electrode and a second external electrode; a first busbar electrically connected to the first external electrode; a second busbar electrically connected to the second external electrode; an insulator sandwiched between the first busbar and the second busbar so as to form a laminated structure together with the first busbar and the second busbar; a case in which the capacitor element is housed; and a sealing resin filled inside the case so as to embed the capacitor element and allow the first busbar, the second busbar, and the insulator to be drawn out from the inside to the outside, wherein the first busbar has a first terminal located outside the sealing resin and the sealing resin is directed toward the first terminal The second busbar has a first main projection that protrudes from the first terminal, and a first sub-projection that protrudes from the sealing resin at a position different from the first main projection so as not to face the first terminal, and the length of the projection from the sealing resin is shorter than that of the first main projection; the second busbar has a second terminal located outside the sealing resin, a second main projection that protrudes from the sealing resin so as to face the second terminal, and a second sub-projection that protrudes from the sealing resin at a position different from the second main projection so as not to face the second terminal, and the length of the projection from the sealing resin is shorter than that of the second main projection; and the insulator extends to cover the boundary between the first sub-projection and the insulator when viewed from the direction in which the first busbar protrudes from the sealing resin.

[0015] In a conventional capacitor module, assuming that moisture enters the capacitor element existing inside the encapsulating resin from the boundary between the first bus bar existing outside the encapsulating resin and the insulator, the capacitor element expands by absorbing the moisture, and the first bus bar, the second bus bar, and the insulator existing around the capacitor element are pushed against the encapsulating resin by the expanded capacitor element, so that the encapsulating resin may crack (for example, get fissures). When the encapsulating resin cracks, moisture easily enters the capacitor element from the encapsulating resin itself, so that the reliability of the capacitor module may decrease, such as the electrical characteristics of the capacitor element deteriorating.

[0016] Regarding such circumstances, in the capacitor module of the present invention, the length by which the first sub-protrusion protrudes from the encapsulating resin is shorter than the length by which the first main-protrusion protrudes from the encapsulating resin. Therefore, in the capacitor module of the present invention, assuming that moisture enters the capacitor element existing inside the encapsulating resin from the boundary between the first bus bar existing outside the encapsulating resin and the insulator, the length of the path through which moisture enters the capacitor element along the first bus bar from the boundary between the first sub-protrusion and the insulator is considered to be shorter than the length of the path through which moisture enters the capacitor element along the first bus bar from the boundary between the first main-protrusion and the insulator.

[0017] On the other hand, in the capacitor module of the present invention, the insulator extends so as to cover the boundary between the first sub-protrusion and the insulator when viewed from the direction in which the first bus bar protrudes from the encapsulating resin. Thereby, in the capacitor module of the present invention, it is possible to lengthen the path from the boundary between the first sub-protrusion and the insulator to the capacitor element along the first bus bar, that is, the relatively short path through which moisture can enter the capacitor element inside the encapsulating resin from outside the encapsulating resin, by the extent that the insulator extends as described above.

[0018] Therefore, in the capacitor module of the present invention, it is possible to lengthen the relatively short path through which moisture can penetrate from the outside of the sealing resin to the capacitor element inside the sealing resin, thereby suppressing the penetration of moisture from the outside of the sealing resin to the capacitor element inside the sealing resin. In the capacitor module of the present invention, since it is possible to suppress the penetration of moisture from the outside of the sealing resin to the capacitor element inside the sealing resin, it is possible to suppress cracking of the sealing resin caused by the expansion of the capacitor element due to moisture absorption, as described above, and as a result, it is possible to suppress a decrease in reliability. As described above, the capacitor module of the present invention makes it possible to improve moisture resistance, which is related to reliability.

[0019] The following describes a specific example of the capacitor module of the present invention.

[0020] Figure 1 is a schematic perspective view showing an example of the capacitor module of the present invention. Figure 2 is a schematic perspective view showing an example of the capacitor module in Figure 1 with the sealing resin removed. Figure 3 is a schematic perspective view showing an example of the capacitor module in Figure 1 with both the sealing resin and the case removed.

[0021] In Figure 1, etc., the first direction D1, the second direction D2, and the third direction D3 are perpendicular to each other.

[0022] As shown in Figures 1, 2, and 3, the capacitor module 1 includes a capacitor element 10, a first busbar 20, a second busbar 30, an insulator 40, a case 50, and a sealing resin 60.

[0023] <Capacitor element> Figure 4 is a schematic perspective view showing an example of a capacitor element in Figure 3. Figure 5 is a schematic cross-sectional view showing an example of a cross-section along the line a1-a2 of the capacitor element in Figure 4.

[0024] As shown in Figures 4 and 5, the capacitor element 10 includes a base body 11, a first external electrode 12a, and a second external electrode 12b.

[0025] The base body 11 is a wound body in which a first metallized film 13a and a second metallized film 13b are stacked in a first direction D1 and wound together. In other words, the capacitor element 10 is a wound-type film capacitor in which metallized films are stacked and wound together.

[0026] The capacitor element 10 may also be a multilayer film capacitor (for example, in the shape of a rectangular parallelepiped) formed by stacking metallized films.

[0027] The base body 11 has a first end face 11a and a second end face 11b that are opposite to the second direction D2.

[0028] The base body 11 further has a side surface 11c that extends in the second direction D2 so as to connect the periphery of the first end surface 11a and the second end surface 11b.

[0029] 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 (second direction D2 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.

[0030] Whether the base body 11 was pressed to have a flattened cross-sectional shape can be confirmed, for example, by checking whether there are press marks on the base body 11.

[0031] 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.

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

[0033] 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.

[0034] 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 second direction D2, 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.

[0035] The second metallized film 13b comprises a second dielectric film 14b and a second metal layer 15b.

[0036] 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.

[0037] 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 second direction D2, 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.

[0038] In the base body 11, the adjacent first metallized film 13a and second metallized film 13b are shifted in the second direction D2 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.

[0039] In the base body 11, as described above, the adjacent first metallized film 13a and second metallized film 13b are shifted in the second direction D2. 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.

[0040] Since the base body 11 is formed by winding the first metallized film 13a and the second metallized film 13b in a state where they are 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 body 11 can be said to be a wound body formed by winding the first dielectric film 14a, the first metal layer 15a, the second dielectric film 14b, and the second metal layer 15b in a state where they are stacked in the first direction D1 in that order.

[0041] 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 either the first dielectric film 14a or the second dielectric film 14b in between.

[0042] 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 a fuse portion include the electrode patterns disclosed in Japanese Patent Application Publication No. 2004-363431 and Japanese Patent Application Publication No. Hei 5-251266.

[0043] The second metal layer 15b may also be provided with a fuse portion, similar to the first metal layer 15a.

[0044] The first dielectric film 14a may contain a curable resin as its main component.

[0045] In this specification, the main component means the component with the highest weight percentage, preferably the component with a weight percentage higher than 50% by weight.

[0046] The curable resin may be a thermosetting resin or a photocurable resin.

[0047] In this specification, thermosetting resins mean resins that can be cured by heat, but this does not limit the curing method. Therefore, thermosetting resins include resins that can be cured by methods other than heat (e.g., light, electron beam, etc.), as long as they can be cured by heat. In addition, depending on the material, the reaction may be initiated by the reactivity of the material itself, and resins that proceed to cure without necessarily being subjected to external heat are also considered thermosetting resins. The same applies to photocurable resins; as long as they can be cured by light, they also include resins that can be cured by methods other than light (e.g., heat, etc.).

[0048] The curable resin is preferably composed of a cured product of a first organic material having hydroxyl groups (OH groups) and a second organic material having isocyanate groups (NCO groups). In this case, the curable resin is composed of a cured product having urethane bonds obtained by the reaction of the hydroxyl groups of the first organic material and the isocyanate groups of the second organic material.

[0049] The presence of urethane bonding in the first dielectric film 14a can be confirmed by analysis using Fourier transform infrared spectrophotometer (FT-IR).

[0050] When a curable resin is obtained by the reaction described above, 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 hydroxyl groups and isocyanate groups. In this case, the first dielectric film 14a may contain either one of hydroxyl groups and isocyanate groups, or both hydroxyl groups and isocyanate groups.

[0051] The presence of hydroxyl groups and / or isocyanate groups in the first dielectric film 14a can be confirmed by analysis using a Fourier transform infrared spectrophotometer (FT-IR).

[0052] Examples of the first organic material include phenoxy resin, polyvinyl acetal resin, and polyvinyl butyral resin.

[0053] Multiple types of organic materials may be used in combination as the first organic material.

[0054] 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 form of these polyisocyanates may be used, or a mixture of at least one of these polyisocyanates and its modified form may be used.

[0055] Multiple types of organic materials may be used in combination as the second organic material.

[0056] The first dielectric film 14a may contain a thermoplastic resin as its main component.

[0057] Examples of thermoplastic resins include polypropylene resin, polyethersulfone resin, polyetherimide resin, and polyarylate resin.

[0058] The first dielectric film 14a may further contain additives for adding various functions.

[0059] Examples of additives include leveling agents used to impart smoothness.

[0060] The additive preferably has a functional group that reacts with hydroxyl groups and / or isocyanate groups, 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 hydroxyl groups, epoxy groups, silanol groups, and carboxyl groups.

[0061] 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.

[0062] The constituent materials 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.

[0063] 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.

[0064] 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.

[0065] The thicknesses of the first dielectric film 14a and the second dielectric film 14b are measured using an optical film thickness gauge.

[0066] 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.

[0067] 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.

[0068] The constituent materials 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.

[0069] 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.

[0070] 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.

[0071] The thicknesses of the first metal layer 15a and the second metal layer 15b are measured by observing the cross-sections of the first metallized film 13a and the second metallized film 13b along the first direction D1 using a transmission electron microscope (TEM).

[0072] 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.

[0073] 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 in 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 in 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.

[0074] 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.

[0075] 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.

[0076] The first external electrode 12a and the second external electrode 12b have opposite polarities. For example, the first external electrode 12a may be the negative electrode (N pole) and the second external electrode 12b may be the positive electrode (P pole), or the first external electrode 12a may be the positive electrode (P pole) and the second external electrode 12b may be the negative electrode (N pole).

[0077] 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.

[0078] The constituent materials 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.

[0079] 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.

[0080] The above configuration is merely one example of a capacitor element 10. In other words, the capacitor element 10 is not limited to the above configuration.

[0081] In the above example, the capacitor element 10 is shown to be a film capacitor, but the capacitor element 10 may be a capacitor element other than a film capacitor.

[0082] The number of capacitor elements 10 in the capacitor module 1 is not particularly limited. 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 it may have multiple capacitor elements 10.

[0083] If the capacitor module 1 has multiple capacitor elements 10, the configurations of the multiple capacitor elements 10 may be the same as each other, different from each other, or partially different.

[0084] When the capacitor module 1 has multiple capacitor elements 10, the arrangement of the multiple capacitor elements 10 when housed inside the case 50 is not particularly limited. For example, the multiple capacitor elements 10 may be arranged in one row or in multiple rows when housed inside the case 50. 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 in multiple directions.

[0085] <First bus bar> The first busbar 20 is electrically connected to the first external electrode 12a. The first busbar 20 may be connected to the first external electrode 12a by, for example, welding or by a joining member such as solder. As a result, the first external electrode 12a is electrically drawn out through the first busbar 20. For example, if the first external electrode 12a is the negative electrode, the first busbar 20 becomes the lead conductor for the negative electrode.

[0086] The first busbar 20 does not need to be bent inside the sealing resin 60. In the examples shown in Figures 1, 2, and 3, the first busbar 20 has a first type portion 20a that extends from the inside to the outside of the sealing resin 60. The first type portion 20a is not bent inside the sealing resin 60.

[0087] The first busbar 20 may be bent inside the sealing resin 60.

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

[0089] <Second bus bar> The second busbar 30 is electrically connected to the second external electrode 12b. The second busbar 30 may be connected to the second external electrode 12b by, for example, welding or by a joining member such as solder. As a result, the second external electrode 12b is electrically drawn out through the second busbar 30. For example, if the second external electrode 12b is the positive electrode, the second busbar 30 becomes the lead conductor for the positive electrode.

[0090] The second busbar 30 may be bent inside the sealing resin 60. In the examples shown in Figures 1, 2, and 3, the second busbar 30 has a second type portion 30a that extends inside the sealing resin 60 in a direction along the side surface 11c of the element 11 on which the first external electrode 12a and the second external electrode 12b are not provided, and a third type portion 30b that extends from the inside to the outside of the sealing resin 60 relative to the second type portion 30a. The second type portion 30a and the third type portion 30b extend in directions that intersect each other, and in this case, in directions perpendicular to each other. In other words, the second busbar 30 is bent inside the sealing resin 60 at the connection point between the second type portion 30a and the third type portion 30b. Note that although the second busbar 30 is bent at the second type portion 30a (see Figures 7 and 8 described later), it does not have to be bent at the second type portion 30a.

[0091] The second busbar 30 does not need to be bent inside the sealing resin 60.

[0092] Examples of materials that can be used to construct the second busbar 30 include metals such as copper, oxygen-free copper, aluminum, and alloys containing at least one of these. In particular, it is preferable that the constituent material of the second busbar 30 be copper or oxygen-free copper. When the constituent material of the second busbar 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).

[0093] The constituent material of the second busbar 30 may be the same as the constituent material of the first busbar 20, or it may be different from the constituent material of the first busbar 20.

[0094] The thickness of the second busbar 30 may be the same as the thickness of the first busbar 20, or it may be different from the thickness of the first busbar 20.

[0095] <insulator> The insulator 40 is sandwiched between the first busbar 20 and the second busbar 30 so as to form a laminated structure together with the first busbar 20 and the second busbar 30. Specifically, the first busbar 20, the insulator 40, and the second busbar 30 are stacked in order to form a laminated structure. In such a laminated structure, the creepage distance between the first busbar 20 and the second busbar 30 is ensured by the insulator 40, thereby ensuring insulation between the first busbar 20 and the second busbar 30 (short circuits between the first busbar 20 and the second busbar 30 are prevented).

[0096] Examples of materials that make up the insulator 40 include resin.

[0097] The insulator 40 may include, for example, a super engineering plastic as the resin. In this case, the insulating properties of the insulator 40 tend to improve.

[0098] If the insulator 40 contains a super engineering plastic, the super engineering plastic is preferably a polyphenylene sulfide resin. In this case, the tracking resistance of the insulator 40 is more easily improved, and thus the insulating properties of the insulator 40 are more easily improved.

[0099] The thickness of the insulator 40 may be the same as the thickness of the first busbar 20 and the second busbar 30, or it may be different from the thickness of the first busbar 20 and the second busbar 30.

[0100] The insulator 40 is preferably in the form of a plate. In other words, the insulator 40 is preferably an insulating plate.

[0101] In this specification, the term "insulating board" also includes forms such as insulating paper, insulating sheets, and insulating films.

[0102] It is preferable that the insulator 40 is bent together with the first busbar 20 and the second busbar 30. In the example shown in Figure 1, the insulator 40 is bent in an L-shape together with the first busbar 20 and the second busbar 30 on the side opposite to the capacitor element 10. When the first busbar 20, the second busbar 30, and the insulator 40 are bent in this way, the creepage distance between the first busbar 20 and the second busbar 30 is more easily secured, making it easier to ensure insulation between the first busbar 20 and the second busbar 30 (making it easier to prevent short circuits between the first busbar 20 and the second busbar 30). Furthermore, when the first busbar 20, the second busbar 30, and the insulator 40 are bent, the electromagnetic fields generated by the first busbar 20 and the second busbar 30 tend to cancel each other out, making it easier to reduce the equivalent series inductance (ESL) between the first busbar 20 and the second busbar 30.

[0103] <Case> The capacitor element 10 is housed inside the case 50.

[0104] It is preferable that the capacitor element 10 is housed inside the case 50 so as to be separated from the inner surface of the case 50.

[0105] The case 50 may be a bottomed cylindrical shape with an opening 51. In the example shown in Figure 1, the case 50 is a bottomed cylindrical shape with an opening 51 at one end in the first direction D1.

[0106] If the case 50 is a bottomed cylindrical shape with an opening 51, it may have a bottom portion 52 facing the opening 51 and a side wall portion 53 extending from the bottom portion 52 toward the opening 51. In the example shown in Figure 1, the case 50 has a bottom portion 52 facing the opening 51 in a first direction D1, and a side wall portion 53 extending in the first direction D1 toward the opening 51 from the periphery of the bottom portion 52.

[0107] The shape of case 50 may be other than the shape described above.

[0108] Examples of case 50 include resin cases, metal cases, and so on.

[0109] If case 50 is a resin case, examples of resins that make up the resin case include liquid crystal polymer, polyphenylene sulfide resin, polybutylene terephthalate resin, etc. Among these, it is preferable that the resin case contains liquid crystal polymer.

[0110] As for 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 polymers formed from the above-mentioned components.

[0111] The resin case preferably contains an inorganic filler in addition to the liquid crystal polymer.

[0112] 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.

[0113] The form of the inorganic filler is not particularly limited, and examples include forms having a longitudinal direction, such as fibrous or plate-like shapes. 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.

[0114] 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.

[0115] In this specification, a filler is described as being in the form of a plate, meaning 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 the cross-sectional diameter / maximum height ≥ 3.

[0116] Preferably, the inorganic filler has at least a portion of it that is oriented in the direction from the bottom 52 side toward the opening 51 side on the side wall portion 53 of the case 50, and a portion that is oriented toward the outer circumference of the side wall portion 53, and is dispersed inside the case 50.

[0117] The inorganic filler material is preferably 5 μm or larger in diameter and 50 μm or larger in length.

[0118] It is preferable that the inorganic filler is dispersed throughout the case 50 without agglomerating.

[0119] Examples of inorganic fillers include fibrous glass fillers, plate-shaped talc, or mica. Among these, it is preferable that the inorganic filler primarily contains fibrous glass fillers.

[0120] 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.

[0121] The resin case is manufactured by methods such as injection molding and 3D printing (three-dimensional modeling).

[0122] If case 50 is a metal case, examples of metals that make up the metal case include elemental metals such as aluminum, magnesium, iron, stainless steel, and copper, as well as alloys containing at least one of these elemental metals. In particular, it is preferable that the metal case contains aluminum or an aluminum alloy.

[0123] The metal case is manufactured by methods such as impact molding and 3D printing (three-dimensional molding).

[0124] <Sealing resin> The sealing resin 60 is filled inside the case 50 so that the capacitor element 10 is embedded within it. This fixes the capacitor element 10 in place within the case 50 using the sealing resin 60.

[0125] The sealing resin 60 is filled inside the case 50 so that the first busbar 20, the second busbar 30, and the insulator 40 are drawn out from the inside to the outside. In the example shown in Figure 1, the first busbar 20, the second busbar 30, and the insulator 40 are drawn out from the inside to the outside of the sealing resin 60 and also from the inside to the outside of the case 50. The first busbar 20 and the second busbar 30 (specifically, the first terminal 21 and the second terminal 31 described later), which are drawn out in this manner, are electrically connected to an object to be connected (not shown), such as a substrate or device, by laser welding, for example, with insulation between them ensured by the insulator 40.

[0126] In the example shown in Figure 1, when viewed from the direction in which the first busbar 20 and the second busbar 30 protrude from the sealing resin 60 (first direction D1 in Figure 1), the first terminal 21 and the second terminal 31, which will be described later, are misaligned (misaligned in the third direction D3 in Figure 1). However, the first terminal 21 and the second terminal 31 do not necessarily have to be misaligned (they may overlap).

[0127] If the capacitor element 10 is housed inside the case 50 so as to be separated from the inner surface of the case 50, it is preferable that the sealing resin 60 is filled between the capacitor element 10 and the case 50, specifically between the outer surface of the capacitor element 10 and the inner surface of the case 50. Furthermore, it is preferable that the sealing resin 60 is filled not only between the capacitor element 10 and the case 50, but also in the area extending from the opening 51 of the case 50 to the capacitor element 10.

[0128] From the viewpoint of suppressing the intrusion of moisture from the sealing resin 60 itself into the capacitor element 10, it is preferable that the thickness of the sealing resin 60 at the opening 51 of the case 50 is large. The thickness of the sealing resin 60 at the opening 51 of the case 50 is preferably sufficiently large within the allowable range of the overall volume (size) of the capacitor element 10 and the case 50, specifically preferably 2 mm or more, and more preferably 4 mm or more. Furthermore, it is preferable to position the capacitor element 10 on the bottom 52 side rather than the opening 51 side within the case 50 so that the thickness of the sealing resin 60 over the capacitor element 10 is larger on the opening 51 side than on the bottom 52 side.

[0129] The thickness of the sealing resin 60 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.

[0130] In the first direction D1, the relationship between the height of the case 50 and the height of the sealing resin 60 is such that the thickness of the sealing resin 60 at the opening 51 of the case 50 is as large as possible, and it may extend to the inside of the case 50, or it may fill it to the brim, or it may slightly overflow due to surface tension.

[0131] As the sealing resin 60, it is preferable to appropriately select a resin with low moisture permeability from the viewpoint of suppressing the penetration of moisture from the sealing resin 60 itself into the capacitor element 10. Examples include epoxy resin, silicone resin, and urethane resin. Examples of curing agents for epoxy resin include amine curing agents and imidazole curing agents.

[0132] As the sealing resin 60, 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.

[0133] The following describes the configurations of the first busbar 20, the second busbar 30, and the insulator 40, which are features of the capacitor module 1. In addition to Figures 1, 2, and 3, Figures 6, 7, and 8 below will also be referenced in the following description.

[0134] Figure 6 is a schematic plan view showing an example of the capacitor module in Figure 1 as viewed from a first direction. Figure 7 is a schematic cross-sectional view showing an example of a cross-section of the capacitor module in Figure 6 along the line A1-A2. Figure 8 is a schematic cross-sectional view showing an example of a cross-section of the capacitor module in Figure 6 along the line B1-B2.

[0135] The first busbar 20 has a first terminal 21 located outside the sealing resin 60. The first terminal 21 is located on the side of the first busbar 20 opposite to the capacitor element 10, rather than on the side of the first busbar 20 opposite to the capacitor element 10. The first terminal 21 is electrically connected to an object to be connected, such as a substrate or device, by laser welding, for example.

[0136] The number of first terminals 21 on the first busbar 20 is not particularly limited. That is, the first busbar 20 may have one first terminal 21 or may have multiple first terminals 21.

[0137] The first busbar 20 has a first main projection 22 that protrudes from the sealing resin 60 toward the first terminal 21. In the example shown in Figure 1, the first main projection 22 protrudes from the sealing resin 60 in a first direction D1.

[0138] The first main projection 22 may or may not protrude from the case 50, as well as from the sealing resin 60. In the example shown in Figure 1, the first main projection 22 protrudes from the sealing resin 60 in a first direction D1, and also protrudes from the opening 51 of the case 50 in the first direction D1.

[0139] The first main projection 22 protrudes from the sealing resin 60 and may or may not be bent on its way to the opposite side of the sealing resin 60, that is, towards the first terminal 21. In the example shown in Figure 1, the first main projection 22 protrudes from the sealing resin 60 in a first direction D1 and is bent in an L-shape in a second direction D2 on its way to the opposite side of the sealing resin 60, that is, towards the first terminal 21.

[0140] The number of first main protrusions 22 on the first busbar 20 is not particularly limited. That is, the first busbar 20 may have one first main protrusion 22 or may have multiple first main protrusions 22.

[0141] The first busbar 20 protrudes from the sealing resin 60 at a position different from the first main projection 22 so as not to face the first terminal 21, and has a first sub-projection 23 whose length protruding from the sealing resin 60 is shorter than that of the first main projection 22. In the example shown in Figure 1, the first sub-projection 23 protrudes from the sealing resin 60 in a first direction D1 at a position different from that of the first main projection 22.

[0142] The first sub-protrusion 23 may protrude from the sealing resin 60 and also from the case 50, or it may not protrude from the case 50. In the example shown in Figure 1, the first sub-protrusion 23 protrudes from the sealing resin 60 in the first direction D1 and also from the opening 51 of the case 50 in the first direction D1.

[0143] The first sub-projection 23 may or may not be bent as it protrudes from the sealing resin 60 and moves toward the opposite side of the sealing resin 60. In the example shown in Figure 1, the first sub-projection 23 protrudes from the sealing resin 60 in the first direction D1 and does not bend as it moves toward the opposite side of the sealing resin 60.

[0144] The number of first sub-projections 23 on the first busbar 20 is not particularly limited. That is, the first busbar 20 may have one first sub-projection 23 or may have multiple first sub-projections 23.

[0145] The number of first main protrusions 22 and first sub-protrusions 23 in the first busbar 20 may be the same or different. If the number of first main protrusions 22 and first sub-protrusions 23 are different, the number of first main protrusions 22 may be greater than or less than the number of first sub-protrusions 23.

[0146] The second busbar 30 has a second terminal 31 located outside the sealing resin 60. The second terminal 31 is located on the side of the second busbar 30 opposite to the capacitor element 10, rather than on the side of the second busbar 30 opposite to the capacitor element 10. The second terminal 31 is electrically connected to an object to be connected, such as a substrate or device, by laser welding, for example.

[0147] The number of second terminals 31 in the second busbar 30 is not particularly limited. That is, the second busbar 30 may have one second terminal 31 or may have multiple second terminals 31.

[0148] The second busbar 30 has a second main projection 32 that protrudes from the sealing resin 60 toward the second terminal 31. In the example shown in Figure 1, the second main projection 32 protrudes from the sealing resin 60 in a first direction D1.

[0149] The second main projection 32 may or may not protrude from the case 50, as well as from the sealing resin 60. In the example shown in Figure 1, the second main projection 32 protrudes from the sealing resin 60 in the first direction D1, as well as from the opening 51 of the case 50 in the first direction D1.

[0150] The second main projection 32 protrudes from the sealing resin 60 and may or may not be bent on its way to the opposite side of the sealing resin 60, that is, towards the second terminal 31. In the example shown in Figure 1, the second main projection 32 protrudes from the sealing resin 60 in the first direction D1 and is bent in an L-shape in the second direction D2 on its way to the opposite side of the sealing resin 60, that is, towards the second terminal 31.

[0151] The number of second main protrusions 32 in the second busbar 30 is not particularly limited. That is, the second busbar 30 may have one second main protrusion 32 or may have multiple second main protrusions 32.

[0152] The second busbar 30 protrudes from the sealing resin 60 at a position different from the second main projection 32 so as not to face the second terminal 31, and has a second sub-projection 33 whose length protruding from the sealing resin 60 is shorter than that of the second main projection 32. In the example shown in Figure 1, the second sub-projection 33 protrudes from the sealing resin 60 in the first direction D1 at a position different from that of the second main projection 32.

[0153] The second sub-protrusion 33 may protrude from the sealing resin 60 and also from the case 50, or it may not protrude from the case 50. In the example shown in Figure 1, the second sub-protrusion 33 protrudes from the sealing resin 60 in the first direction D1 and also from the opening 51 of the case 50 in the first direction D1.

[0154] The second sub-projection 33 may or may not be bent as it protrudes from the sealing resin 60 and moves toward the opposite side of the sealing resin 60. In the example shown in Figure 1, the second sub-projection 33 protrudes from the sealing resin 60 in the first direction D1 and does not bend as it moves toward the opposite side of the sealing resin 60.

[0155] The number of second sub-projections 33 on the second busbar 30 is not particularly limited. That is, the second busbar 30 may have one second sub-projection 33 or may have multiple second sub-projections 33.

[0156] The number of second main protrusions 32 and second sub-protrusions 33 in the second busbar 30 may be the same or different. If the number of second main protrusions 32 and second sub-protrusions 33 are different, the number of second main protrusions 32 may be greater than or less than the number of second sub-protrusions 33.

[0157] In conventional capacitor modules, if moisture is assumed to penetrate from the boundary between the first busbar and the insulator located outside the encapsulating resin into the capacitor element located inside the encapsulating resin, the capacitor element will absorb the moisture and expand. At the same time, the first busbar, second busbar, and insulator surrounding the capacitor element will be pressed against the encapsulating resin by the expanded capacitor element, which may cause the encapsulating resin to crack (for example, develop a fissure).

[0158] In light of these circumstances, in the capacitor module 1, the length of the first sub-protrusion 23 protruding from the sealing resin 60 is shorter than the length of the first main protrusion 22 protruding from the sealing resin 60. Therefore, in the capacitor module 1, if we assume that moisture penetrates from the boundary between the first busbar 20, which is outside the sealing resin 60, and the insulator 40, it is considered that the length of the path through which moisture penetrates from the boundary between the first sub-protrusion 23 and the insulator 40 to the capacitor element 10 via the first busbar 20 is shorter than the length of the path through which moisture penetrates from the boundary between the first main protrusion 22 and the insulator 40 to the capacitor element 10 via the first busbar 20.

[0159] In contrast, in the capacitor module 1, the insulator 40 extends to cover the boundary P1 between the first sub-protrusion 23 and the insulator 40 when viewed from the direction in which the first busbar 20 protrudes from the sealing resin 60. As a result, in the capacitor module 1, the path from the boundary P1 between the first sub-protrusion 23 and the insulator 40 along the first busbar 20 to the capacitor element 10, that is, the relatively short path through which moisture can penetrate from outside the sealing resin 60 to the capacitor element 10 inside the sealing resin 60, can be made longer by the amount that the insulator 40 extends, as described above.

[0160] Therefore, in the capacitor module 1, it is possible to lengthen the relatively short path through which moisture can penetrate from the outside of the sealing resin 60 to the capacitor element 10 inside the sealing resin 60, thereby suppressing the penetration of moisture from the outside of the sealing resin 60 to the capacitor element 10 inside the sealing resin 60. In the capacitor module 1, it is possible to suppress the penetration of moisture from the outside of the sealing resin 60 to the capacitor element 10 inside the sealing resin 60, and as a result, it is possible to suppress cracking of the sealing resin 60 caused by the expansion of the capacitor element 10 due to moisture absorption, as described above, and consequently, it is possible to suppress a decrease in reliability. As described above, the capacitor module 1 can improve moisture resistance, which is related to reliability.

[0161] Furthermore, as described above, the capacitor module 1 can suppress the intrusion of moisture into the capacitor element 10, making it less likely that the first busbar 20, the second busbar 30, and the insulator 40 surrounding the capacitor element 10 will be pushed by the expanded capacitor element 10 due to moisture absorption. Therefore, in the capacitor module 1, the relative positions of the first busbar 20, the second busbar 30, and the insulator 40 are less likely to change, and consequently, the first busbar 20 and the second busbar 30 are less likely to separate from each other. Thus, the capacitor module 1 can suppress the increase in equivalent series inductance (ESL) between the first busbar 20 and the second busbar 30.

[0162] Furthermore, in capacitor module 1, when electrically connecting the first busbar 20 and the second busbar 30 to an object to be connected, such as a substrate or device, and especially when laser welding the first busbar 20 and the second busbar 30 to the object to be connected, it is desirable to increase the positional accuracy of the first busbar 20 and the second busbar 30 with respect to the object to be connected, for reasons such as facilitating the connection of the first busbar 20 and the second busbar 30 to the object to be connected. In contrast, in capacitor module 1, as described above, the positional relationship between the first busbar 20 and the second busbar 30 is less likely to change, making it possible to increase the positional accuracy of the first busbar 20 and the second busbar 30 with respect to the object to be connected.

[0163] The direction in which the first busbar 20 protrudes from the sealing resin 60 refers to the direction in which the first busbar 20 extends immediately after protruding from the sealing resin 60, and in the example shown in Figure 1, etc., it corresponds to the first direction D1.

[0164] In the example shown in Figure 1, the insulator 40 extends in an overhang shape relative to the first sub-projection 23 so as to cover the boundary P1 between the first sub-projection 23 and the insulator 40. However, the shape of the portion of the insulator 40 that extends in this way (overhang) is not particularly limited.

[0165] The length of the shortest path between the first sub-protrusion 23 and the first external electrode 12a may be shorter than the length of the shortest path between the second sub-protrusion 33 and the second external electrode 12b. In this case, the path from the boundary between the first sub-protrusion 23 and the insulator 40 along the first busbar 20 to the capacitor element 10 (specifically, the first external electrode 12a) will be shorter than the path from the boundary between the second sub-protrusion 33 and the insulator 40 along the second busbar 30 to the capacitor element 10 (specifically, the second external electrode 12b).

[0166] Even in the above-mentioned case, as described above, because the insulator 40 extends to cover the boundary P1 between the first sub-protrusion 23 and the insulator 40, it is possible to prioritize lengthening the relatively short path among the above paths, which is the path from the boundary between the first sub-protrusion 23 and the insulator 40 along the first busbar 20 to the capacitor element 10 (specifically, the first external electrode 12a). With the above configuration, it is possible to efficiently suppress the intrusion of moisture from the outside of the sealing resin 60 into the capacitor element 10 inside the sealing resin 60.

[0167] Figure 9 is a schematic perspective view showing another example of the capacitor module of the present invention. Figure 10 is a schematic plan view showing an example of the capacitor module in Figure 9 viewed from a first direction. Figure 11 is a schematic cross-sectional view showing an example of a cross-section along the line C1-C2 of the capacitor module in Figure 10.

[0168] As shown in Figures 9, 10, and 11, in capacitor module 2, similar to capacitor module 1, the insulator 40 extends to cover the boundary P1 between the first sub-protrusion 23 and the insulator 40 when viewed from the direction in which the first busbar 20 protrudes from the sealing resin 60. As a result, in capacitor module 2, similar to capacitor module 1, the path from the boundary P1 between the first sub-protrusion 23 and the insulator 40 along the first busbar 20 to the capacitor element 10, that is, the relatively short path through which moisture can penetrate from outside the sealing resin 60 to the capacitor element 10 inside the sealing resin 60, can be made longer by the extension of the insulator 40 as described above.

[0169] On the other hand, in conventional capacitor modules, even if we assume that moisture penetrates into the capacitor element inside the encapsulating resin from the boundary between the second busbar and the insulator located outside the encapsulating resin, the capacitor element will absorb the moisture and expand. At the same time, the first busbar, the second busbar, and the insulator surrounding the capacitor element will be pressed against the encapsulating resin by the expanded capacitor element, which may cause the encapsulating resin to crack (for example, develop a fissure).

[0170] In light of these circumstances, in capacitor module 2, the length of the second sub-protrusion 33 protruding from the sealing resin 60 is shorter than the length of the second main protrusion 32 protruding from the sealing resin 60. Therefore, in capacitor module 2, if we assume that moisture penetrates from the boundary between the second busbar 30, which is outside the sealing resin 60, and the insulator 40, it is considered that the length of the path through which moisture penetrates from the boundary between the second sub-protrusion 33 and the insulator 40 to the capacitor element 10 via the second busbar 30 is shorter than the length of the path through which moisture penetrates from the boundary between the second main protrusion 32 and the insulator 40 via the second busbar 30 to the capacitor element 10.

[0171] In contrast, as shown in Figures 9, 10, and 11, in the capacitor module 2, it is preferable that the insulator 40 extends to cover the boundary P2 between the second sub-protrusion 33 and the insulator 40 when viewed from the direction in which the second busbar 30 protrudes from the sealing resin 60. This makes it possible to lengthen the path from the boundary P2 between the second sub-protrusion 33 and the insulator 40 along the second busbar 30 to the capacitor element 10, that is, the relatively short path through which moisture can penetrate from outside the sealing resin 60 to the capacitor element 10 inside the sealing resin 60, by the amount that the insulator 40 extends, as described above.

[0172] Therefore, the capacitor module 2 can sufficiently suppress the intrusion of moisture from the outside of the sealing resin 60 into the capacitor element 10 inside the sealing resin 60. Because the capacitor module 2 can sufficiently suppress the intrusion of moisture from the outside of the sealing resin 60 into the capacitor element 10 inside the sealing resin 60, it is possible to sufficiently suppress cracking of the sealing resin 60 caused by the expansion of the capacitor element 10 due to moisture absorption, as described above, and as a result, it is possible to sufficiently suppress the decrease in reliability. In this way, the capacitor module 2 can sufficiently improve moisture resistance, which is related to reliability.

[0173] The direction in which the second busbar 30 protrudes from the sealing resin 60 refers to the direction in which the second busbar 30 extends immediately after protruding from the sealing resin 60, and in the example shown in Figure 9, etc., it corresponds to the first direction D1.

[0174] In the example shown in Figure 9, the insulator 40 extends in an overhang shape relative to the second sub-projection 33 so as to cover the boundary P2 between the second sub-projection 33 and the insulator 40. However, the shape of the portion of the insulator 40 that extends in this way (overhang) is not particularly limited.

[0175] The first sub-protrusion 23 and the second sub-protrusion 33 may overlap with the insulator 40 in between. In this case, since there are many points where moisture can penetrate from outside the sealing resin 60, such as the boundary between the first sub-protrusion 23 and the insulator 40, and the boundary between the second sub-protrusion 33 and the insulator 40, it is thought that moisture can easily penetrate from outside the sealing resin 60 to the capacitor element 10 inside the sealing resin 60 through these points.

[0176] Even in the above-mentioned case, as described above, the insulator 40 extends to cover the boundary P1 between the first sub-protrusion 23 and the insulator 40, and also extends to cover the boundary P2 between the second sub-protrusion 33 and the insulator 40, thereby making it possible to sufficiently suppress the intrusion of moisture from outside the sealing resin 60 into the capacitor element 10 inside the sealing resin 60.

[0177] The first main projection 22 and the second main projection 32 may or may not overlap with the insulator 40 in between.

[0178] The following describes a configuration example in which moisture intrusion into the capacitor element 10 is considered to have a significant impact, assuming that moisture penetrates into the capacitor element 10 located inside the sealing resin 60 from areas outside the sealing resin 60, such as the boundary between the first busbar 20 and the insulator 40, and the boundary between the second busbar 30 and the insulator 40. Even with the following configuration example, the capacitor module 1, etc., can suppress cracking of the sealing resin 60 caused by the expansion of the capacitor element 10 due to moisture absorption.

[0179] (Configuration Example 1) Within the encapsulating resin 60, at least one selected from the group consisting of the first busbar 20, the second busbar 30, and the insulator 40 may face the surface of the capacitor element 10 where the first external electrode 12a and the second external electrode 12b are not provided. In the examples shown in Figures 7, 8, and 11, within the encapsulating resin 60, the second busbar 30 and the insulator 40 of the first busbar 20 and second busbar 30 face the side surface 11c of the element 11 where the first external electrode 12a and the second external electrode 12b are not provided.

[0180] On the other hand, when the capacitor element 10 expands due to the absorption of moisture, the capacitor element 10 is more likely to expand on the surface side where the first external electrode 12a and the second external electrode 12b are not provided than on the surface side where the first external electrode 12a and the second external electrode 12b are provided. In the examples shown in Figures 7, 8, and 11, the capacitor element 10 is more likely to expand on the side surface 11c of the base body 11 than on the first end surface 11a and the second end surface 11b of the base body 11. In other words, in the examples shown in Figures 7, 8, and 11, the capacitor element 10 is more likely to expand in the first direction D1 and the third direction D3, which the side surface 11c of the base body 11 faces, than in the second direction D2, which the first end surface 11a and the second end surface 11b of the base body 11 face. Thus, if the capacitor element 10 is prone to expanding on the side 11c of the base body 11 (in the first direction D1 in Figures 7, 8, and 11, etc.), the first busbar 20, the second busbar 30, and the insulator 40 that face the side 11c of the base body 11 (the second busbar 30 and the insulator 40 in Figures 7, 8, and 11, etc.) will be more easily pressed against the sealing resin 60 by the expanded capacitor element 10, which may result in the sealing resin 60 becoming more prone to cracking.

[0181] Even in the above-described case, as mentioned above, by having the insulator 40 extend to cover the boundary P1 between the first sub-protrusion 23 and the insulator 40, preferably by having the insulator 40 extend to cover the boundary P1 between the first sub-protrusion 23 and the insulator 40, and also extend to cover the boundary P2 between the second sub-protrusion 33 and the insulator 40, it is possible to suppress the intrusion of moisture from the outside of the sealing resin 60 into the capacitor element 10 inside the sealing resin 60, and as a result, it is possible to suppress cracking of the sealing resin 60 caused by the expansion of the capacitor element 10 due to moisture absorption.

[0182] In this configuration example, if at least one of the first busbar 20 and the second busbar 30 faces the surface of the capacitor element 10 where the first external electrode 12a and the second external electrode 12b are not provided, the equivalent series inductance (ESL) of the capacitor module 1, etc., tends to decrease.

[0183] In this configuration example, at least one selected from the group consisting of the first busbar 20, the second busbar 30, and the insulator 40 may or may not be in contact with the surface of the capacitor element 10 that does not have the first external electrode 12a and the second external electrode 12b, when facing the surface of the capacitor element 10 that does not have the first external electrode 12a and the second external electrode 12b. For example, the insulator 40 may or may not be in contact with the surface of the capacitor element 10 that does not have the first external electrode 12a and the second external electrode 12b.

[0184] In this configuration example, within the encapsulating resin 60, the first busbar 20 may extend longer than the second busbar 30 along the surface of the capacitor element 10 where the first external electrode 12a and the second external electrode 12b are not provided. In the examples shown in Figures 7, 8, and 11, the first busbar 20 extends longer than the second busbar 30 along the side surface 11c of the body 11 where the first external electrode 12a and the second external electrode 12b are not provided within the encapsulating resin 60.

[0185] (Configuration example 2) The surface of the capacitor element 10 that does not have the first external electrode 12a and the second external electrode 12b may face the opening 51 of the case 50. In the examples shown in Figures 7, 8, and 11, the side surface 11c of the body 11 that does not have the first external electrode 12a and the second external electrode 12b faces the opening 51 of the case 50.

[0186] When the capacitor element 10 expands due to the absorption of moisture, as described above, the capacitor element 10 is more likely to expand on the surface side where the first external electrode 12a and the second external electrode 12b are not provided than on the surface side where the first external electrode 12a and the second external electrode 12b are provided. In the examples shown in Figures 7, 8, and 11, the capacitor element 10 is more likely to expand on the side surface 11c of the base body 11 than on the first end surface 11a and the second end surface 11b of the base body 11. In other words, in the examples shown in Figures 7, 8, and 11, the capacitor element 10 is more likely to expand in the first direction D1 and the third direction D3, which the side surface 11c of the base body 11 faces, than in the second direction D2, which the first end surface 11a and the second end surface 11b of the base body 11 face. Furthermore, inside the case 50, the sealing resin 60 is often filled more in the region between the capacitor element 10 and the opening 51 than in other regions. Therefore, as described above, if the capacitor element 10 is prone to expanding on the side 11c of the base body 11 facing the opening 51 of the case 50 (in the first direction D1 in Figures 7, 8, 11, etc.), the area of ​​the sealing resin 60 that is pressed against the first busbar 20, the second busbar 30, and the insulator 40 (in Figures 7, 8, 11, etc., the second busbar 30 and the insulator 40) by the expanded capacitor element 10 will increase, and as a result, there is a possibility that the sealing resin 60 will become prone to cracking over a wide area.

[0187] Even in the above-described case, as mentioned above, by having the insulator 40 extend to cover the boundary P1 between the first sub-protrusion 23 and the insulator 40, preferably by having the insulator 40 extend to cover the boundary P1 between the first sub-protrusion 23 and the insulator 40, and also extend to cover the boundary P2 between the second sub-protrusion 33 and the insulator 40, it is possible to suppress the intrusion of moisture from the outside of the sealing resin 60 into the capacitor element 10 inside the sealing resin 60, and as a result, it is possible to suppress cracking of the sealing resin 60 caused by the expansion of the capacitor element 10 due to moisture absorption.

[0188] (Configuration Example 3) If there are multiple capacitor elements 10, the multiple capacitor elements 10 may be arranged along the bottom 52 of the case 50. Furthermore, the first bus bar 20 and the second bus bar 30 may extend across the multiple capacitor elements 10.

[0189] In this case, moisture that seeps in from areas outside the sealing resin 60, such as the boundary between the first busbar 20 and the insulator 40, and the boundary between the second busbar 30 and the insulator 40, can easily travel along the first busbar 20 and the second busbar 30 and penetrate into the multiple capacitor elements 10 located inside the sealing resin 60. When the multiple capacitor elements 10 expand due to absorbing moisture, the area of ​​the sealing resin 60 that is pressed against the first busbar 20, the second busbar 30, and the insulator 40 by the expanded multiple capacitor elements 10 becomes larger, potentially making the sealing resin 60 more prone to cracking over a wide area.

[0190] Even in the above-described case, as mentioned above, by having the insulator 40 extend to cover the boundary P1 between the first sub-protrusion 23 and the insulator 40, preferably by having the insulator 40 extend to cover the boundary P1 between the first sub-protrusion 23 and the insulator 40, and also extend to cover the boundary P2 between the second sub-protrusion 33 and the insulator 40, it is possible to suppress the intrusion of moisture from the outside of the sealing resin 60 into the multiple capacitor elements 10 inside the sealing resin 60, and as a result, it is possible to suppress cracking of the sealing resin 60 caused by the expansion of the multiple capacitor elements 10 due to moisture absorption.

[0191] (Configuration example 4) If there are multiple capacitor elements 10, the multiple capacitor elements 10 may be arranged in the same direction (third direction D3 in Figure 1, etc.) along the bottom 52 of the case 50. Furthermore, if the first busbar 20 has multiple first terminals 21, the multiple first terminals 21 may be arranged with spacing between them along the same direction as the multiple capacitor elements 10 (third direction D3 in Figure 1, etc.), and the first main protrusions 22 corresponding to each first terminal 21 may be arranged along the same direction as the multiple capacitor elements 10 (third direction D3 in Figure 1, etc.), with a first sub-protrusion 23 in between. Furthermore, if the second busbar 30 has a plurality of second terminals 31, the plurality of second terminals 31 may be arranged with a gap between them along the same direction as the plurality of capacitor elements 10 (third direction D3 in Figure 1, etc.), and the second main protrusions 32 corresponding to each second terminal 31 may be arranged along the same direction as the plurality of capacitor elements 10 (third direction D3 in Figure 1, etc.), with a second sub-protrusion 33 in between.

[0192] In this case, moisture that enters from areas outside the sealing resin 60, such as the boundary between the first busbar 20 and the insulator 40, and the boundary between the second busbar 30 and the insulator 40, can easily penetrate into the multiple capacitor elements 10 inside the sealing resin 60 through multiple paths that travel along the first busbar 20 and the second busbar 30 from the boundaries between the first sub-protrusion 23 and the insulator 40, and the boundaries between the second sub-protrusion 33 and the insulator 40. When the multiple capacitor elements 10 expand due to absorbing moisture, the area of ​​the sealing resin 60 that is pressed against the first busbar 20, the second busbar 30, and the insulator 40 by the expanded multiple capacitor elements 10 becomes larger, and as a result, there is a possibility that the sealing resin 60 will become more prone to cracking over a wide area.

[0193] Even in the above-described case, as mentioned above, by having the insulator 40 extend to cover the boundary P1 between the first sub-protrusion 23 and the insulator 40, preferably by having the insulator 40 extend to cover the boundary P1 between the first sub-protrusion 23 and the insulator 40, and also extend to cover the boundary P2 between the second sub-protrusion 33 and the insulator 40, it is possible to suppress the intrusion of moisture from the outside of the sealing resin 60 into the multiple capacitor elements 10 inside the sealing resin 60, and as a result, it is possible to suppress cracking of the sealing resin 60 caused by the expansion of the multiple capacitor elements 10 due to moisture absorption.

[0194] In Figure 1, etc., an example of a configuration in which the first main projection 22 is arranged with the first sub-projection 23 in between is shown, in which the first main projection 22 is located at both ends in the direction in which the first main projection 22 and the first sub-projection 23 are arranged (third direction D3 in Figure 1, etc.). However, the first sub-projection 23 may be located at both ends in the direction in which the first main projection 22 and the first sub-projection 23 are arranged (third direction D3 in Figure 1, etc.), or the first main projection 22 may be located at one end in the direction in which the first main projection 22 and the first sub-projection 23 are arranged (third direction D3 in Figure 1, etc.) and the first sub-projection 23 may be located at the other end.

[0195] In Figure 1, etc., an example of a configuration in which the second main projection 32 is arranged with the second sub-projection 33 in between is shown, in which the second main projection 32 is located at both ends in the direction in which the second main projection 32 and the second sub-projection 33 are arranged (third direction D3 in Figure 1, etc.). However, the second sub-projection 33 may be located at both ends in the direction in which the second main projection 32 and the second sub-projection 33 are arranged (third direction D3 in Figure 1, etc.), or the second main projection 32 may be located at one end in the direction in which the second main projection 32 and the second sub-projection 33 are arranged (third direction D3 in Figure 1, etc.), and the second sub-projection 33 may be located at the other end.

[0196] Although configuration examples 1 to 4 have been described individually above, multiple configuration examples may be combined. Even in this case, the capacitor module 1, etc., makes it possible to suppress the intrusion of moisture from the outside of the sealing resin 60 into the capacitor element 10 inside the sealing resin 60, and as a result, it is possible to suppress cracking of the sealing resin 60 caused by the expansion of the capacitor element 10 due to moisture absorption.

[0197] The capacitor module of the present invention is not limited to the above-described form, and various applications and modifications can be made within the scope of the present invention regarding the configuration, manufacturing conditions, etc., of the capacitor module.

[0198] The capacitor module of the present invention is useful for automotive applications, such as inverters, chargers, DC-DC converters, etc., installed in electric vehicles.

[0199] The capacitor module of the present invention can be applied not only to automotive applications but also to various fields such as power electronics. [Explanation of Symbols]

[0200] 1, 2 Capacitor Modules 10 Capacitor element 11 Base Body 11a First end face of the base body 11b Second end face of the base body 11c Side view of the base 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 the first dielectric film 14ab Second main surface of the first dielectric film 14b Second Dielectric Film 14ba First main surface of the second dielectric film 14bb Second main surface of the second dielectric film 15a 1st metal layer 15b 2nd metal layer 20 First Bus Bar 20a Class 1 part 21 1st terminal 22 1st main protrusion 23 1st secondary protrusion 30 Second Bus Bar 30a Type 2 part 30b Type 3 part 31 2nd terminal 32 2nd main protrusion 33 2nd secondary protrusion 40 Insulator 50 cases 51 Opening 52 Bottom 53 Side wall section 60 Sealing resin D1 1st direction D2 2nd direction D3 Third direction P1 Boundary between the first secondary projection and the insulator P2 Boundary between the second secondary projection and the insulator

Claims

1. A capacitor element having a first external electrode and a second external electrode, A first busbar electrically connected to the first external electrode, A second busbar electrically connected to the second external electrode, An insulator sandwiched between the first busbar and the second busbar so as to form a laminated structure together with the first busbar and the second busbar, A case in which the aforementioned capacitor element is housed, The capacitor element is embedded in the case, and the case is filled with a sealing resin such that the first busbar, the second busbar, and the insulator are drawn out from the inside to the outside. The first busbar has a first terminal located outside the sealing resin, a first main projection that protrudes from the sealing resin toward the first terminal, and a first sub-projection that protrudes from the sealing resin at a position different from the first main projection so as not to be toward the first terminal, and the length of the projection from the sealing resin is shorter than that of the first main projection. The second busbar has a second terminal located outside the sealing resin, a second main projection that protrudes from the sealing resin toward the second terminal, and a second sub-projection that protrudes from the sealing resin at a different position from the second main projection so as not to face the second terminal, and whose length protruding from the sealing resin is shorter than that of the second main projection. A capacitor module characterized in that the insulator extends to cover the boundary between the first sub-protrusion and the insulator when viewed from the direction in which the first busbar protrudes from the sealing resin.

2. The capacitor module according to claim 1, wherein the length of the shortest path between the first sub-protrusion and the first external electrode is shorter than the length of the shortest path between the second sub-protrusion and the second external electrode.

3. The capacitor module according to claim 1 or 2, wherein the insulator extends to cover the boundary between the second sub-protrusion and the insulator when viewed from the direction in which the second busbar protrudes from the sealing resin.

4. The capacitor module according to claim 3, wherein the first sub-protrusion and the second sub-protrusion overlap with the insulator in between.

5. A capacitor module according to any one of claims 1 to 4, wherein, inside the sealing resin, at least one selected from the group consisting of the first busbar, the second busbar, and the insulator faces the surface of the capacitor element where the first external electrode and the second external electrode are not provided.

6. The capacitor module according to any one of claims 1 to 5, wherein the case is a bottomed cylindrical shape with an opening, and has a bottom facing the opening and a side wall extending from the bottom toward the opening.

7. The capacitor module according to claim 6, wherein the surface of the capacitor element on which the first external electrode and the second external electrode are not provided faces the opening of the case.

8. Multiple capacitor elements are arranged along the bottom of the case, The capacitor module according to claim 6 or 7, wherein the first busbar and the second busbar extend across a plurality of capacitor elements.

9. Multiple capacitor elements are arranged in the same direction along the bottom of the case, Multiple first terminals are arranged in the same direction as the multiple capacitor elements, with spacing between them. Each of the first main protrusions corresponding to the first terminal is arranged along the same direction as the plurality of capacitor elements, with the first sub-protrusions in between. Multiple second terminals are arranged in the same direction as the multiple capacitor elements, with spaces between them. The capacitor module according to any one of claims 6 to 8, wherein the second main protrusions corresponding to each of the second terminals are arranged in the same direction as the plurality of capacitor elements, with the second sub-protrusions in between.

10. The capacitor module according to any one of claims 1 to 9, wherein the capacitor element is a film capacitor.

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