Capacitor element

Abstract

A capacitor element (1) is provided with: a capacitor part (10) including an anode plate (11) having a porous part (11B) on at least one main surface of a core part (11A), a dielectric layer (13) provided on the surface of the porous part (11B), and a cathode layer (12) provided on the surface of the dielectric layer (13); and a sealing layer (20) provided so as to cover the capacitor part (10). The cathode layer (12) includes a solid electrolyte layer (12A) provided on the surface of the dielectric layer (13). The solid electrolyte layer (12A) contains a conductive polymer. The sealing layer (20) contains an insulating resin (41) and a flat inorganic filler (42). In the sealing layer (20) located in a portion covering the capacitor part (10), the flat inorganic filler (42) is oriented in a plane direction orthogonal to the thickness direction.

Description

Technical Field

[0001] The present invention relates to capacitor elements. Background Art

[0002] Patent Document 1 discloses a capacitor array comprising: a plurality of solid electrolytic capacitor elements formed by dividing a solid electrolytic capacitor sheet; a sheet-shaped first sealing layer; and a sheet-shaped second sealing layer. The solid electrolytic capacitor sheet comprises: an anode plate formed of a valve-acting metal; a porous layer provided on at least one principal surface of the anode plate; a dielectric layer provided on the surface of the porous layer; and a cathode layer including a solid electrolyte layer provided on the surface of the dielectric layer. The solid electrolytic capacitor sheet has a first principal surface and a second principal surface facing each other in the thickness direction. The first principal surface side of each of the plurality of solid electrolytic capacitor elements is arranged on the first sealing layer. The second sealing layer is arranged to cover the plurality of solid electrolytic capacitor elements on the first sealing layer from the second principal surface side. The solid electrolytic capacitor elements are separated by slit-shaped sheet removal portions.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-167361 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] In the capacitor array described in Patent Document 1, if external oxygen and moisture diffuse through the sealing layer and penetrate into the solid electrolytic capacitor elements, the conductive polymer contained in the solid electrolyte layer may degrade over time. In this case, the solid electrolyte layer is easily separated from the dielectric layer due to stress, causing a decrease in electrostatic capacitance and equivalent series resistance (ESR), and in some cases, causing delamination.

[0008] Patent Document 1 states that a stress relaxation layer may be provided between the solid electrolytic capacitor element and the first or second sealing layer, and that the stress relaxation layer may also be provided within the chip removal portion between adjacent solid electrolytic capacitor elements. Patent Document 1 states that the stress relaxation layer is composed of an insulating resin such as epoxy resin, phenolic resin, or silicone resin, and preferably further contains an inorganic filler such as silica particles, alumina particles, or metal particles.

[0009] According to Patent Document 1, providing a stress relaxation layer in the aforementioned locations is believed to alleviate stress generated between the interior and exterior of the capacitor array without compromising the required performance (resistance, barrier properties, etc.) of the outermost conductor and insulating portion of the solid electrolytic capacitor element, or the required performance (e.g., ease of adhesion to wiring, smooth formation, etc.) of the sealing layer. However, there is room for improvement in suppressing the permeation of oxygen and moisture into the solid electrolytic capacitor element.

[0010] The above-mentioned problem is not limited to the structure in which a plurality of capacitor units are arranged inside the sealing layer, but also occurs in the structure in which a single capacitor unit is arranged inside the sealing layer.

[0011] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a capacitor element in which oxygen and moisture are unlikely to permeate into the capacitor portion through a sealing layer.

[0012] Solutions for solving problems

[0013] The capacitor element of the present invention comprises: a capacitor portion comprising an anode plate having a porous portion on at least one main surface of a core portion, a dielectric layer disposed on a surface of the porous portion, and a cathode layer disposed on a surface of the dielectric layer; and a sealing layer disposed so as to cover the capacitor portion. The cathode layer comprises a solid electrolyte layer disposed on a surface of the dielectric layer. The solid electrolyte layer contains a conductive polymer. The sealing layer contains an insulating resin and a flat inorganic filler. In the portion of the sealing layer covering the capacitor portion, the flat inorganic filler is oriented in a plane direction perpendicular to the thickness direction.

[0014] Effects of the Invention

[0015] According to the present invention, it is possible to provide a capacitor element in which oxygen and moisture are unlikely to permeate into the capacitor portion via the sealing layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional view schematically showing an example of the capacitor element of the present invention.

[0017] Figure 2 yes Figure 1 A top view of the capacitor element along line II-II is shown.

[0018] Figure 3 yes Figure 1 An enlarged view of the portion shown in III.

[0019] Figure 4 A and B are schematic diagrams for explaining the flatness of the inorganic filler.

[0020] Figure 5 A, B, and C are schematic diagrams for explaining an example of a method for forming a sealing layer.

[0021] Figure 6 This is a graph showing the temporal change in ESR (ESR ratio) at 100 kHz.

[0022] Figure 7 This is a graph showing the temporal change (ΔCs) of electrostatic capacitance at 120 kHz. DETAILED DESCRIPTION

[0023] The following describes the capacitor element of the present invention. Furthermore, the present invention is not limited to the following configurations and may be modified appropriately without changing the gist of the present invention. Furthermore, inventions combining multiple preferred configurations described below also constitute the present invention.

[0024] In this specification, terms that express the relationship between elements (such as "vertical", "parallel", "orthogonal", etc.) and terms that express the shape of an element do not have strict meanings, but also include essentially the same range, such as expressions with differences of several percent.

[0025] The following drawings are schematic diagrams, and their dimensions, aspect ratios, and other scales may differ from those of actual products. In the drawings, identical or corresponding parts are denoted by the same reference numerals. In addition, identical elements are denoted by the same reference numerals in each drawing, and duplicate descriptions are omitted.

[0026] Figure 1 It is a cross-sectional view schematically showing an example of the capacitor element of the present invention. Figure 2 yes Figure 1 A top view of the capacitor element along line II-II is shown.

[0027] Figure 1 and Figure 2 The capacitor element 1 shown includes a capacitor portion 10 and a sealing layer 20 provided to cover the capacitor portion 10. Figure 1 In the illustrated example, the sealing layer 20 includes a first sealing layer 21 covering the capacitor portion 10 and a second sealing layer 22 covering the first sealing layer 21 .

[0028] exist Figure 1 and Figure 2 In the example shown, two capacitor units 10 are arranged inside the sealing layer 20. The number of capacitor units 10 arranged inside the sealing layer 20 is not particularly limited, and may be one or more.

[0029] like Figure 1 and Figure 2As shown, when multiple capacitor units 10 are arranged within the sealing layer 20, adjacent capacitor units 10 are preferably separated from each other by through-grooves 30 that penetrate the capacitor units 10 in the thickness direction (Z direction). In this case, the through-grooves 30 are preferably filled with an insulating material such as the sealing layer 20.

[0030] When adjacent capacitor sections 10 are separated by through-slots 30, it suffices that the adjacent capacitor sections 10 are physically separated by the through-slots 30. Thus, adjacent capacitor sections 10 may be electrically disconnected or electrically connected. The width of the through-slots 30, i.e., the distance between adjacent capacitor sections 10, may be constant in the thickness direction (Z direction) or may decrease in the thickness direction.

[0031] When a plurality of capacitor units 10 are arranged inside the sealing layer 20, the plurality of capacitor units 10 can be arranged in a plane direction orthogonal to the thickness direction (Z direction) (i.e., a plane direction parallel to the X-axis and the Y-axis), or can be arranged in a stacked manner in the thickness direction, or a combination of the two. The plurality of capacitor units 10 can be arranged regularly or irregularly. The size and shape of the capacitor units 10 can be the same, or they can be partially or completely different. The structures of the capacitor units 10 are preferably the same, but capacitor units 10 with different structures can also be included.

[0032] The capacitor unit 10 includes an anode plate 11 having a porous portion 11B on at least one main surface of a core 11A, a dielectric layer 13 provided on a surface of the porous portion 11B, and a cathode layer 12 provided on a surface of the dielectric layer 13. Figure 1 In the illustrated example, the anode plate 11 has the porous portions 11B on both main surfaces of the core portion 11A. However, the porous portion 11B may be provided on only one main surface of the core portion 11A.

[0033] Cathode layer 12 includes solid electrolyte layer 12A provided on the surface of dielectric layer 13. Solid electrolyte layer 12A contains a conductive polymer. Since cathode layer 12 includes solid electrolyte layer 12A, capacitor unit 10 constitutes a solid electrolytic capacitor.

[0034] Cathode layer 12 preferably further includes a conductor layer 12B provided on the surface of solid electrolyte layer 12A.

[0035] like Figure 1 As shown, the sealing layer 20 is preferably provided on two main surfaces facing each other in the thickness direction of the capacitor unit 10. The sealing layer 20 protects the capacitor unit 10.

[0036] The sealing layer 20 may be composed of only one layer or may be composed of two or more layers. When the sealing layer 20 is composed of two or more layers, the materials constituting each layer may be the same or different.

[0037] Figure 3 yes Figure 1 An enlarged view of the portion shown in III. Figure 3 In the figure, the paths of oxygen and water are represented by arrows.

[0038] like Figure 3 As shown, the sealing layer 20 contains an insulating resin 41 and a flat inorganic filler 42. When the sealing layer 20 includes the first sealing layer 21 and the second sealing layer 22, at least the first sealing layer 21 only needs to contain the flat inorganic filler 42.

[0039] In the sealing layer 20 located at the portion covering the capacitor portion 10, the flat inorganic fillers 42 are oriented in a plane direction perpendicular to the thickness direction. Figure 3 , flat inorganic fillers 42 oriented in the X direction in the sealing layer 20 located in the portion covering the capacitor portion 10 are schematically shown.

[0040] The flat inorganic filler 42 is less likely to have gas permeation than the insulating resin 41. The flat inorganic filler 42 is oriented in a plane direction (for example, an arbitrary direction parallel to the XY plane, such as the X direction) as shown in FIG. Figure 3 As shown by arrow a in FIG, the diffusion and permeation paths of oxygen and moisture through sealing layer 20 to the upper surface (or lower surface) of capacitor unit 10 can be extended. This can suppress degradation of the conductive resin contained in solid electrolyte layer 12A. Consequently, the lifespan characteristics of capacitor element 1 can be improved.

[0041] The flat inorganic filler 42 preferably has a flatness of 1 / 2 or greater as measured according to the following definition. The flat inorganic filler 42 may have rounded corners to improve fluidity within the sealing layer 20. Furthermore, the flat inorganic filler 42 may be fibrous.

[0042] Figure 4 A and B are schematic diagrams for explaining the flatness of the inorganic filler.

[0043] like Figure 4 As shown in Figures A and B, in the cross-sectional shape of the inorganic filler, the z-direction is the smallest direction of the inorganic filler, the x-direction is the largest of the two directions perpendicular to the z-direction, and the y-direction is the smallest of the two directions perpendicular to the z-direction. Furthermore, assuming the x-direction is the major diameter t1 and the z-direction is the minor diameter t2, the flattening factor f is expressed as f = 1 - (t2 / t1). If the inorganic filler is spherical (circular in cross-section), the flattening factor is 0, while if the particle is completely flattened, the flattening factor is 1.

[0044] As described above, the flat inorganic filler 42 preferably has an oblateness of 1 / 2 or greater. Specifically, the major diameter t1 is preferably at least twice the minor diameter t2 (2×t2≤t1). On the other hand, when the median diameter t3 is defined as the dimension in the y direction, the relationship 2×t2≤t3≤t1 is preferably satisfied.

[0045] Furthermore, when measuring the flatness of the inorganic filler in a finished capacitor element, the sealing layer portion can be cut out from the capacitor element, the resin component removed, and then the flatness of the inorganic filler can be measured by observation using an electron microscope such as a scanning electron microscope (SEM).

[0046] If the major axis of the flat inorganic filler 42 is too small, orientation is not easily achieved. Therefore, the major axis of the flat inorganic filler 42 is preferably 100 nm or more. On the other hand, the major axis of the flat inorganic filler 42 is, for example, 10 μm or less.

[0047] If the minor diameter of the flat inorganic filler 42 is too large, the electrical resistance tends to increase. Therefore, the minor diameter of the flat inorganic filler 42 is preferably 5 μm or less. On the other hand, the minor diameter of the flat inorganic filler 42 is, for example, 50 nm or more.

[0048] In this specification, “the flat inorganic filler is oriented in the plane direction” means that the orientation ratio in the plane direction obtained by the following method is 60% or more.

[0049] In such Figure 3 In the cross section shown, let N1 be the total number of flat inorganic fillers 42 to be measured, and let N'1 be the number of flat inorganic fillers 42 whose major axis direction is tilted relative to the plane direction such that θ1 is -30° ≤ θ1 ≤ 30°. The orientation ratio OR1 in the plane direction is expressed by the formula OR1 = (N'1 / N1) × 100. For example, it is preferable to measure at least ten flat inorganic fillers 42 located in a portion of the sealing layer 20 covering the capacitor unit 10, away from the through-groove 30 or other through-portion.

[0050] In the portion of the sealing layer 20 covering the capacitor unit 10, the orientation ratio of the flat inorganic fillers 42 in the plane direction is preferably 70% or greater, more preferably 80% or greater. On the other hand, in the portion of the sealing layer 20 covering the capacitor unit 10, the orientation ratio of the flat inorganic fillers 42 in the plane direction may be 100% or less, and may be 100%.

[0051] The filling rate of the flat inorganic filler 42 in the sealing layer 20 (for example, the first sealing layer 21) is preferably 20% or more, more preferably 30% or more. On the other hand, the filling rate of the flat inorganic filler 42 is preferably 60% or less, more preferably 50% or less. The filling rate of the flat inorganic filler 42 can be adjusted as follows: Figure 3 The ratio is calculated as the area ratio of the flat inorganic filler 42 in the sealing layer 20 (for example, the first sealing layer 21 ) in the illustrated cross section.

[0052] When adjacent capacitor portions 10 are separated by through-grooves 30 and the through-grooves 30 are filled with the sealing layer 20 (for example, the first sealing layer 21 ), the flat inorganic fillers 42 are preferably oriented in the thickness direction in the portion of the sealing layer 20 that fills the through-grooves 30 . Figure 3 FIG. 2 schematically shows a flat inorganic filler 42 oriented in the Z direction in the sealing layer 20 located at a portion filling the through-groove 30 .

[0053] The flat inorganic filler 42 is oriented in the thickness direction (Z direction), such as Figure 3 As shown by arrow b in FIG, the path for oxygen and moisture to diffuse and penetrate the side surfaces of capacitor unit 10 through sealing layer 20 can be extended. This can suppress degradation of the conductive resin contained in solid electrolyte layer 12A. As a result, the life characteristics of capacitor element 1 can be improved.

[0054] Furthermore, in the through grooves 30 where the core portion 11A and the porous portion 11B are exposed on the end surface of the anode plate 11 , the flat inorganic fillers 42 which are not easily permeable to gases are oriented in the thickness direction, thereby improving the effect of suppressing the diffusion and penetration of oxygen and moisture.

[0055] In this specification, “the flat inorganic filler is oriented in the thickness direction” means that the orientation ratio in the thickness direction obtained by the following method is 60% or more.

[0056] In such Figure 3 In the cross section shown, let N2 be the total number of flat inorganic fillers 42 to be measured, and let N'2 be the number of flat inorganic fillers 42 whose major axis direction is tilted relative to the thickness direction such that θ2 is -30° ≤ θ2 ≤ 30°. The orientation ratio OR2 in the thickness direction is expressed by the formula OR2 = (N'2 / N2) × 100. For example, it is preferable to measure at least 10 flat inorganic fillers 42 located at the center in the thickness direction of the sealing layer 20 that is filled in the through-groove 30 or other through-portion.

[0057] In the portion of the sealing layer 20 that fills the through-groove 30, the orientation ratio of the flat inorganic filler 42 in the thickness direction is preferably 70% or greater, more preferably 80% or greater, at the center in the thickness direction of the through-groove 30. On the other hand, in the portion of the sealing layer 20 that fills the through-groove 30, the orientation ratio of the flat inorganic filler 42 in the thickness direction at the center in the thickness direction of the through-groove 30 may be 100% or less, and may be 100%.

[0058] When the through-groove 30 is filled with the sealing layer 20 (for example, the first sealing layer 21 ), the major diameter of the flat inorganic filler 42 is preferably equal to the width of the through-groove 30 ( Figure 1 and Figure 2 Middle W 30 The length of the through-groove 30 is preferably less than 1 / 3, and more preferably less than 1 / 5, of the length shown. In this case, the flat inorganic filler 42 is not excessively large, and therefore, when the through-groove 30 is filled with the sealing layer 20 (e.g., the first sealing layer 21), the flat inorganic filler 42 is less likely to clog the through-groove 30. Furthermore, if the width of the through-groove 30 is not constant, the width of the narrowest portion is defined as the width of the through-groove 30.

[0059] The lower limit of the major axis of the flat inorganic filler 42 is not particularly limited, but the major axis of the flat inorganic filler 42 is preferably 1 / 40 or more, more preferably 1 / 20 or more, of the width of the through groove 30 .

[0060] like Figure 1 and Figure 2 As shown, capacitor element 1 preferably further includes first through-hole conductor 51 electrically connected to cathode layer 12 and second through-hole conductor 52 electrically connected to anode plate 11. Capacitor element 1 may include both first through-hole conductor 51 and second through-hole conductor 52, or only one of them.

[0061] Although Figure 1 and Figure 2 Although not shown, capacitor element 1 may further include a third through-hole conductor that is not electrically connected to anode plate 11 and cathode layer 12 .

[0062] First through-hole conductor 51 only needs to be provided on the inner wall surface of first through-hole 31, which penetrates capacitor unit 10 and sealing layer 20 in the thickness direction. First through-hole conductor 51 may be provided only on the inner wall surface of first through-hole 31 or throughout the entire interior of first through-hole 31.

[0063] When viewed in plan from the thickness direction, one first through-hole conductor 51 may be provided inside the cathode layer 12 , or two or more first through-hole conductors 51 may be provided.

[0064] like Figure 1As shown, it is preferable that an insulating material such as a sealing layer 20 is filled between the end surface of the anode plate 11 and the first through-hole conductor 51 .

[0065] When the sealing layer 20 (for example, the first sealing layer 21 ) is filled between the end surface of the anode plate 11 and the first through-hole conductor 51 , Figure 1 Although not shown, in the sealing layer 20 located between the end surface of the filling anode plate 11 and the first through-hole conductor 51 , the flat inorganic filler 42 is preferably oriented in the thickness direction.

[0066] The flat inorganic filler 42 is oriented in the thickness direction. Figure 3 Likewise, the path for oxygen and moisture to diffuse and penetrate the side surfaces of capacitor unit 10 through sealing layer 20 can be extended. This can suppress degradation of the conductive resin contained in solid electrolyte layer 12A, thereby improving the lifespan of capacitor element 1.

[0067] Furthermore, the flat inorganic filler 42 has a higher thermal conductivity than the insulating resin 41, and thus can efficiently dissipate the heat generated by the current flowing through the first through-hole conductor 51 electrically connected to the cathode layer 12. Furthermore, even if heat is generated due to the slight resistance of the first through-hole conductor 51, the heat can be easily dissipated to the outside.

[0068] In the portion of sealing layer 20 located between the end face of filled anode plate 11 and first through-hole conductor 51, the orientation ratio of flat inorganic filler 42 in the thickness direction is preferably 70% or greater, and more preferably 80% or greater, at the center in the thickness direction of first through-hole conductor 51. On the other hand, in the portion of sealing layer 20 located between the end face of filled anode plate 11 and first through-hole conductor 51, the orientation ratio of flat inorganic filler 42 in the thickness direction at the center in the thickness direction of first through-hole conductor 51 may be 100% or less, and may be 100%.

[0069] When the sealing layer 20 (eg, the first sealing layer 21 ) is filled between the end surface of the anode plate 11 and the first through-hole conductor 51 , the major diameter of the flat inorganic filler 42 is preferably equal to the diameter of the first through-hole conductor 51 ( Figure 1 and Figure 2 Middle D 51 (length shown). In this case, the flat inorganic filler 42 is not excessively large, so when the sealing layer 20 (e.g., the first sealing layer 21) is filled between the end face of the anode plate 11 and the first through-hole conductor 51, the flat inorganic filler 42 is less likely to clog. Furthermore, if the diameter of the first through-hole conductor 51 is not constant, the diameter of the narrowest portion is defined as the diameter of the first through-hole conductor 51.

[0070] The lower limit of the major axis of the flat inorganic filler 42 is not particularly limited, but the major axis of the flat inorganic filler 42 is preferably 1 / 40 or more, more preferably 1 / 20 or more, of the diameter of the first through-hole conductor 51 .

[0071] When first through-hole conductor 51 is provided only on the inner wall surface of first through-hole 31, first resin-filled portion 61 filled with a resin material may be provided inside first through-hole conductor 51. In this case, first resin-filled portion 61 is provided in the space within first through-hole 31 surrounded by first through-hole conductor 51. Providing first resin-filled portion 61 eliminates the space within first through-hole 31, thereby suppressing delamination of first through-hole conductor 51. First resin-filled portion 61 may be a conductor or an insulator.

[0072] The first resin-filled portion 61 may contain an insulating resin and a flat inorganic filler, similar to the sealing layer 20 (e.g., the first sealing layer 21). In this case, the insulating resin contained in the first resin-filled portion 61 may be the same as or different from the insulating resin contained in the sealing layer 20. Furthermore, the flat inorganic filler contained in the first resin-filled portion 61 may be the same as or different from the flat inorganic filler contained in the sealing layer 20.

[0073] When the first resin filling portion 61 containing the insulating resin and the flat inorganic filler is provided inside the first through-hole conductor 51, Figure 1 Although not shown, in the first resin-filled portion 61 , the flat inorganic filler is preferably oriented in the thickness direction.

[0074] In first resin-filled portion 61, the orientation ratio of the flat inorganic filler in the thickness direction at the center of first through-hole conductor 51 in the thickness direction is preferably 70% or greater, more preferably 80% or greater. On the other hand, in first resin-filled portion 61, the orientation ratio of the flat inorganic filler in the thickness direction at the center of first through-hole conductor 51 in the thickness direction may be 100% or less, and may be 100%.

[0075] Second through-hole conductor 52 only needs to be provided on the inner wall surface of second through-hole 32, which penetrates capacitor unit 10 and sealing layer 20 in the thickness direction. Second through-hole conductor 52 may be provided only on the inner wall surface of second through-hole 32 or throughout the entire interior of second through-hole 32.

[0076] When viewed in plan from the thickness direction, one second through-hole conductor 52 may be provided inside the cathode layer 12 , or two or more second through-hole conductors 52 may be provided.

[0077] like Figure 1As shown, the second through-hole conductor 52 is preferably electrically connected to the anode plate 11 at the inner wall surface of the second through-hole 32 .

[0078] When second through-hole conductor 52 is provided only on the inner wall surface of second through-hole 32, a second resin-filled portion 62 filled with a resin material may be provided inside second through-hole conductor 52. In this case, second resin-filled portion 62 is provided in the space within second through-hole 32 surrounded by second through-hole conductor 52. By eliminating the space within second through-hole 32 through the provision of second resin-filled portion 62, delamination of second through-hole conductor 52 can be suppressed. Second resin-filled portion 62 may be a conductor or an insulator.

[0079] The second resin-filled portion 62 may contain an insulating resin and a flat inorganic filler, similar to the sealing layer 20 (e.g., the first sealing layer 21). In this case, the insulating resin contained in the second resin-filled portion 62 may be the same as or different from the insulating resin contained in the sealing layer 20. Furthermore, the flat inorganic filler contained in the second resin-filled portion 62 may be the same as or different from the flat inorganic filler contained in the sealing layer 20.

[0080] When the second resin filling portion 62 containing the insulating resin and the flat inorganic filler is provided inside the second through-hole conductor 52, Figure 1 Although not shown, in the second resin-filled portion 62 , the flat inorganic filler is preferably oriented in the thickness direction.

[0081] In the second resin-filled portion 62, the orientation ratio of the flat inorganic filler in the thickness direction at the center of the second through-hole conductor 52 in the thickness direction is preferably 70% or greater, and more preferably 80% or greater. On the other hand, in the second resin-filled portion 62, the orientation ratio of the flat inorganic filler in the thickness direction at the center of the second through-hole conductor 52 in the thickness direction may be 100% or less, and may be 100%.

[0082] The insulating resin 41 contained in the sealing layer 20 (e.g., the first sealing layer 21) preferably comprises an epoxy resin or a phenolic resin. For example, when the capacitor element 1 is disposed on the surface of a resin substrate, the resin substrate is often coated with an epoxy resin or a phenolic resin. Therefore, when the insulating resin 41 comprises an epoxy resin or a phenolic resin, the bonding between the capacitor element 1 and the resin substrate is improved. Furthermore, the interdiffusion of the resins and the anchoring effect provided by the unevenness of the inorganic filler can suppress delamination at the bonding surface.

[0083] The flat inorganic filler 42 contained in the sealing layer 20 (e.g., the first sealing layer 21) is not particularly limited as long as it has insulating properties, but preferably comprises one or more of inorganic glass and a silicic acid compound. The use of these insulating inorganic materials facilitates flattening. Furthermore, the use of materials that are easily processed during laser processing of the sealing layer 20 can suppress the generation of debris. This ensures the insulating properties of the sealing layer 20.

[0084] Examples of inorganic glass include glass fibers, etc. Examples of silicate compounds include minerals such as mica and montmorillonite, etc. These insulating inorganic substances may also be cut or crushed.

[0085] The flat inorganic filler 42 may be an insulating inorganic substance treated with a hydroxyl group. The contact angle can be reduced by the hydroxyl group treatment.

[0086] The sealing layer 20 such as the first sealing layer 21 is formed so as to seal the capacitor portion 10 by, for example, applying an insulating paste containing the insulating resin 41 and the flat inorganic filler 42 and then thermally curing the paste.

[0087] Figure 5 A, B, and C are schematic diagrams for explaining an example of a method for forming a sealing layer.

[0088] like Figure 5 As shown in FIG. 1A , during the application of the insulating paste on the surface of the capacitor portion 10 , the insulating resin 41 has a low viscosity, so the flat inorganic filler 42 flows along the insulating resin 41 ( Figure 5 The flat inorganic filler 42 is oriented in the direction indicated by the arrow in A) and flows toward the through-hole portion such as the through-hole 30. At this time, the portion with a smaller area of ​​the flat inorganic filler 42 becomes the leading portion.

[0089] As time passes, the orientation of the flat inorganic fillers 42 is relaxed, and sedimentation of the flat inorganic fillers 42 occurs. Therefore, the insulating resin 41 needs to be quickly flowed into the through-grooves 30 and other through-grooves.

[0090] In such Figure 5 After the insulating paste is applied to the surface of the capacitor portion 10 as shown in FIG. 1B , while the insulating paste is drying, Figure 5 As shown in FIG. 3 , due to surface tension, the flat inorganic fillers 42 tend to gather on the side surfaces of the capacitor portion 10, so the number of flat inorganic fillers 42 in the center decreases. On the other hand, on the upper or lower surface of the capacitor portion 10, the flat inorganic fillers 42 are oriented in the plane direction along the direction of application of the insulating paste.

[0091] Through the above, the sealing layer 20 (for example, the first sealing layer 21 ) is formed.

[0092] Screen printing is suitable as a method for applying the insulating paste, but the method is not particularly limited, and a method such as dispenser application may also be used.

[0093] When applying the insulating paste to the inside of the through portion of the through groove 30, it is preferable to suction the paste from the back side of the coating. By accelerating the flow of the insulating resin 41, the flat inorganic filler 42 can be oriented.

[0094] like Figure 1 As shown, capacitor element 1 preferably further includes via conductor 70 provided so as to penetrate sealing layer 20 in the thickness direction and having one end portion led out to the surface of sealing layer 20 .

[0095] exist Figure 1 In the example shown, via conductor 70 is electrically connected to cathode layer 12. This allows cathode layer 12 to be electrically conducted to the outside of sealing layer 20 via via conductor 70, thereby enabling electrical connection to the outside of sealing layer 20. The number of via conductors 70 electrically connected to cathode layer 12 may be one or more.

[0096] Although Figure 1 Although not shown, capacitor element 1 may also include a via conductor 70 electrically connected to anode plate 11. In this case, anode plate 11 is electrically led to the outside of sealing layer 20 via via conductor 70, thereby being electrically connected to the outside of sealing layer 20. The number of via conductors 70 electrically connected to anode plate 11 may be one, or two or more.

[0097] When first through-hole conductor 51 or second through-hole conductor 52 is provided in sealing layer 20 , capacitor unit 10 preferably further includes insulating shielding layer 25 provided around first through-hole conductor 51 or second through-hole conductor 52 on at least one main surface of anode plate 11 .

[0098] exist Figure 1 and Figure 2 In the example shown, an insulating material such as a sealing layer 20 is filled between the first through-hole conductor 51 and the capacitor portion 10, and an insulating shielding layer 25 is provided between the insulating material and the cathode layer 12. Figure 1 and Figure 2 In the illustrated example, an insulating shielding layer 25 is provided between the second through-hole conductor 52 and the cathode layer 12 .

[0099] The capacitor unit 10 may further include an insulating shielding layer 25 provided on at least one main surface of the anode plate 11 so as to surround the cathode layer 12. Figure 2As shown, the cathode layer 12 is surrounded by an insulating shielding layer 25 to ensure insulation between the anode plate 11 and the cathode layer 12 and prevent short circuits therebetween. The insulating shielding layer 25 may be provided to partially surround the cathode layer 12, but is preferably provided to surround the entire cathode layer 12.

[0100] like Figure 1 As shown, capacitor element 1 may further include a first external electrode layer 81 electrically connected to cathode layer 12 and a second external electrode layer 82 electrically connected to anode plate 11 .

[0101] The first external electrode layer 81 is provided on the surface of the sealing layer 20 .

[0102] One capacitor unit 10 may include one first external electrode layer 81 or a plurality of first external electrode layers 81 .

[0103] The planar shape of the first external electrode layer 81 when viewed in the thickness direction is not particularly limited. Examples include a rectangle (square or oblong), a polygon other than a rectangle, such as a quadrilateral, triangle, pentagon, or hexagon, a circle, an ellipse, and combinations thereof. Furthermore, the planar shape of the first external electrode layer 81 may be an L-shape, a C-shape (Japanese "コ" shape), a stepped shape, or the like.

[0104] The second external electrode layer 82 is provided on the surface of the sealing layer 20 .

[0105] One capacitor unit 10 may include one or more second external electrode layers 82. The number of second external electrode layers 82 in one capacitor unit 10 may be the same as or different from the number of first external electrode layers 81.

[0106] The planar shape of the second external electrode layer 82 when viewed in the thickness direction is not particularly limited. Examples include a rectangle (square or oblong), a polygon other than a rectangle, such as a quadrilateral, triangle, pentagon, or hexagon, a circle, an ellipse, or a combination thereof. Furthermore, the planar shape of the second external electrode layer 82 may be an L-shape, a C-shape (コ in Japanese), a stepped shape, or the like. The planar shape of the second external electrode layer 82 when viewed in the thickness direction may be the same as or different from the planar shape of the first external electrode layer 81 when viewed in the thickness direction.

[0107] Hereinafter, the detailed structure of capacitor element 1 will be described.

[0108] Examples of the planar shape of capacitor portion 10 when viewed in the thickness direction include a rectangle (square or oblong), a quadrilateral other than a rectangle, a triangle, a pentagon, a hexagon, a circle, an ellipse, and combinations thereof. Furthermore, the planar shape of capacitor portion 10 may be an L-shape, a C-shape (Japanese "コ" shape), a stepped shape, or the like.

[0109] The anode plate 11 is preferably made of a valve metal that exhibits a so-called valve action. Examples of valve metals include single metals such as aluminum, tantalum, niobium, titanium, and zirconium, or alloys containing at least one of these metals. Among these, aluminum or an aluminum alloy is preferred.

[0110] The shape of the anode plate 11 is preferably a flat plate, more preferably a foil. Thus, in this specification, "plate-like" also includes "foil-like".

[0111] Anode plate 11 only needs to have porous portion 11B on at least one main surface of core portion 11A. That is, anode plate 11 may have porous portion 11B on only one main surface of core portion 11A, or on both main surfaces of core portion 11A. Porous portion 11B is preferably a porous layer formed on the surface of core portion 11A, more preferably an etched layer.

[0112] The thickness of anode plate 11 before etching is preferably 60 μm or more and 200 μm or less. The thickness of core portion 11A after etching, which has not been etched, is preferably 15 μm or more and 70 μm or less. The thickness of porous portion 11B is designed based on the required withstand voltage and electrostatic capacitance, but the combined thickness of porous portions 11B on both sides of core portion 11A is preferably 10 μm or more and 180 μm or less.

[0113] The pore size of the porous portion 11B is preferably 10 nm or more and 600 nm or less. The pore size of the porous portion 11B refers to the median pore size D50 measured by a mercury porosimeter. The pore size of the porous portion 11B can be controlled by adjusting various etching conditions, for example.

[0114] Dielectric layer 13, provided on the surface of porous portion 11B, is porous, reflecting the surface condition of porous portion 11B, and has a finely concavo-convex surface profile. Dielectric layer 13 is preferably composed of an oxide film of the aforementioned valve-action metal. For example, when using aluminum foil as anode plate 11, dielectric layer 13 composed of an oxide film can be formed by anodizing the surface of the aluminum foil in an aqueous solution containing ammonium adipate, etc. (also known as chemical conversion treatment).

[0115] The thickness of the dielectric layer 13 is designed according to the required withstand voltage and electrostatic capacitance, but is preferably not less than 10 nm and not more than 100 nm.

[0116] Examples of materials constituting the solid electrolyte layer 12A included in the cathode layer 12 include conductive polymers such as polypyrroles, polythiophenes, and polyanilines. Polythiophenes are preferred, with poly(3,4-ethylenedioxythiophene) known as PEDOT being particularly preferred. These conductive polymers may also contain dopants such as polystyrenesulfonic acid (PSS). Furthermore, the solid electrolyte layer 12A preferably comprises an inner layer that fills the pores (recesses) of the dielectric layer 13 and an outer layer that covers the dielectric layer 13.

[0117] The thickness of solid electrolyte layer 12A from the surface of porous portion 11B is preferably 2 μm or more and 20 μm or less.

[0118] Solid electrolyte layer 12A is formed, for example, by forming a polymer film of poly(3,4-ethylenedioxythiophene) or the like on the surface of dielectric layer 13 using a treatment solution containing a monomer such as 3,4-ethylenedioxythiophene, or by applying a dispersion of a polymer such as poly(3,4-ethylenedioxythiophene) or the like on the surface of dielectric layer 13 and drying it.

[0119] The solid electrolyte layer 12A can be formed in a predetermined region by applying the above-mentioned treatment liquid or dispersion liquid to the surface of the dielectric layer 13 using a method such as sponge transfer, screen printing, dispenser coating, or inkjet printing.

[0120] When cathode layer 12 includes conductive layer 12B, conductive layer 12B includes at least one of a conductive resin layer and a metal layer. Conductive layer 12B may be solely a conductive resin layer or solely a metal layer. Conductive layer 12B preferably covers the entire surface of solid electrolyte layer 12A.

[0121] Examples of the conductive resin layer include a conductive adhesive layer containing at least one conductive filler selected from the group consisting of a silver filler, a copper filler, a nickel filler, and a carbon filler.

[0122] Examples of the metal layer include metal plating and metal foil. The metal layer is preferably composed of at least one metal selected from the group consisting of nickel, copper, silver, and alloys containing these metals as main components. The term "main component" refers to the elemental component with the largest weight ratio.

[0123] Conductor layer 12B includes, for example, a carbon layer provided on the surface of solid electrolyte layer 12A and a copper layer provided on the surface of the carbon layer.

[0124] The carbon layer is provided to electrically and mechanically connect solid electrolyte layer 12A to the copper layer. The carbon layer can be formed in a predetermined area by applying a carbon paste to the surface of solid electrolyte layer 12A using methods such as sponge transfer, screen printing, dispenser coating, and inkjet printing. The thickness of the carbon layer is preferably 2 μm to 20 μm.

[0125] The copper layer can be formed in a predetermined region by applying a copper paste to the surface of the carbon layer using methods such as sponge transfer, screen printing, spray coating, dispenser coating, and inkjet printing. The thickness of the copper layer is preferably 2 μm to 20 μm.

[0126] When the sealing layer 20 is composed of two or more layers, the sealing layers other than the first sealing layer 21 may contain an insulating resin and a flat inorganic filler similar to the first sealing layer 21. In this case, the sealing layers other than the first sealing layer 21 may contain the same insulating resin as the first sealing layer 21, or may contain an insulating resin different from that of the first sealing layer 21. Furthermore, the sealing layers other than the first sealing layer 21 may contain the same flat inorganic filler as the first sealing layer 21, or may contain a flat inorganic filler different from that of the first sealing layer 21.

[0127] When the sealing layer 20 is composed of two or more layers, the sealing layers other than the first sealing layer 21 may be different from the first sealing layer 21 and may not contain insulating resin and flat inorganic fillers. In this case, the sealing layers other than the first sealing layer 21 only need to be composed of insulating materials.

[0128] For example, it is preferable that the sealing layers other than the first sealing layer 21 contain an insulating resin.

[0129] Examples of the insulating resin contained in the sealing layers other than the first sealing layer 21 include epoxy resins and phenol resins.

[0130] It is preferable that the sealing layer other than the first sealing layer 21 further contains an inorganic filler.

[0131] Examples of the inorganic filler contained in the sealing layers other than the first sealing layer 21 include silica particles and alumina particles.

[0132] A layer such as a stress relaxation layer or a moisture-proof film may be provided between the capacitor unit 10 and the sealing layer 20 .

[0133] The insulating shielding layer 25 is made of an insulating material. In this case, the insulating shielding layer 25 is preferably made of an insulating resin.

[0134] Examples of the insulating resin constituting the insulating shielding layer 25 include polyphenylsulfone resin, polyethersulfone resin, cyanate resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, etc.), polyimide resin, polyamide-imide resin, epoxy resin, and derivatives or precursors thereof.

[0135] The insulating shielding layer 25 may be made of the same resin as the sealing layer 20. Unlike the sealing layer 20, if the insulating shielding layer 25 contains an inorganic filler, it may adversely affect the capacitance effective portion of the capacitor unit 10. Therefore, the insulating shielding layer 25 is preferably made of a single resin system.

[0136] The insulating shielding layer 25 can be formed in a predetermined region by applying a shielding material such as a composition containing an insulating resin to the surface of the porous portion 11B by, for example, sponge transfer, screen printing, dispenser coating, or inkjet printing.

[0137] The insulating shielding layer 25 may be formed on the porous portion 11B before or after the dielectric layer 13 is formed.

[0138] The first external electrode layer 81 is electrically connected to the cathode layer 12. Figure 1 In the illustrated example, the first external electrode layer 81 is provided on the surface of the first through-hole conductor 51 and functions as a connection terminal of the capacitor portion 10 .

[0139] Examples of the constituent material of the first external electrode layer 81 include metal materials containing low-resistance metals such as silver, gold, and copper. In this case, the first external electrode layer 81 is formed by plating the surface of the first through-hole conductor 51, for example.

[0140] In order to improve the adhesion between the first external electrode layer 81 and other components, here the adhesion between the first external electrode layer 81 and the first through-hole conductor 51, a mixed material of at least one conductive filler selected from the group consisting of silver filler, copper filler, nickel filler and carbon filler and resin can also be used as the constituent material of the first external electrode layer 81.

[0141] The second external electrode layer 82 is electrically connected to the anode plate 11. Figure 1 In the example shown, the second external electrode layer 82 is provided on the surface of the second through-hole conductor 52 and functions as a connection terminal of the capacitor unit 10. Figure 1 In the illustrated example, the second external electrode layer 82 is electrically connected to the anode plate 11 via the second through-hole conductor 52 , and functions as a connection terminal for the anode plate 11 .

[0142] Examples of the constituent material of the second external electrode layer 82 include metal materials containing low-resistance metals such as silver, gold, and copper. In this case, the second external electrode layer 82 is formed by plating the surface of the second through-hole conductor 52, for example.

[0143] In order to improve the adhesion between the second external electrode layer 82 and other components, here the adhesion between the second external electrode layer 82 and the second through-hole conductor 52, a mixed material of at least one conductive filler selected from the group consisting of silver filler, copper filler, nickel filler and carbon filler and resin can also be used as the constituent material of the second external electrode layer 82.

[0144] The constituent materials of the first external electrode layer 81 and the second external electrode layer 82 are preferably the same in at least kind, but may be different from each other.

[0145] exist Figure 1 In the example shown, each capacitor unit 10 is provided with a first external electrode layer 81 electrically connected to the cathode layer 12 and a second external electrode layer 82 electrically connected to the anode plate 11, but it can also be provided so that at least one of the first external electrode layer 81 and the second external electrode layer 82 is shared by multiple capacitor units 10.

[0146] exist Figure 1 In the illustrated example, the first external electrode layer 81 and the second external electrode layer 82 are provided on both principal surfaces of the sealing layer 20 , but may be provided on only one principal surface of the sealing layer 20 .

[0147] exist Figure 1 In the illustrated example, the first through-hole conductor 51 is electrically connected to the cathode layer 12 via the first external electrode layer 81 and the conductive path conductor 70 .

[0148] exist Figure 1 In the illustrated example, the first external electrode layer 81 is electrically connected to the cathode layer 12 through the via conductor 70 , and functions as a connection terminal for the cathode layer 12 .

[0149] When second through-hole conductor 52 is electrically connected to anode plate 11 at the inner wall surface of second through-hole 32, second through-hole conductor 52 is preferably electrically connected to the end surface of anode plate 11 that faces the inner wall surface of second through-hole 32 in the planar direction. Thus, anode plate 11 is electrically conducted to the outside via second through-hole conductor 52.

[0150] Core 11A and porous portion 11B are preferably exposed at the end surface of anode plate 11 electrically connected to second through-hole conductor 52. In this case, in addition to core 11A, porous portion 11B is also electrically connected to second through-hole conductor 52.

[0151] When viewed in the thickness direction, the second through-hole conductor 52 is preferably electrically connected to the anode plate 11 along the entire circumference of the second through-hole 32. In this case, the connection resistance between the anode plate 11 and the second through-hole conductor 52 is easily reduced, thereby easily reducing the equivalent series resistance (ESR).

[0152] The first through-hole conductor 51 is formed, for example, as follows. First, a through-hole is formed that passes through the capacitor portion 10 in the thickness direction by drilling, laser processing, etc. Next, an insulating material is filled in the through-hole. The first through-hole 31 is formed by drilling, laser processing, etc. on the portion filled with the insulating material. At this time, by making the diameter of the first through-hole 31 smaller than the diameter of the through-hole filled with the insulating material, an insulating material is present between the inner wall surface of the previously formed through-hole and the inner wall surface of the first through-hole 31 in the surface direction. Thereafter, the inner wall surface of the first through-hole 31 is metalized using a metal material containing a low-resistance metal such as copper, gold, or silver, thereby forming the first through-hole conductor 51. When forming the first through-hole conductor 51, the inner wall surface of the first through-hole 31 is metalized, for example, using electroless copper plating, electrolytic copper plating, etc., so that processing becomes easier. Furthermore, the first through-hole conductor 51 may be formed by filling the first through-hole 31 with a metal material, a composite material of metal and resin, or the like, in addition to metallizing the inner wall surface of the first through-hole 31 .

[0153] The second through-hole conductor 52 is formed, for example, as follows. First, a second through-hole 32 is formed that penetrates the capacitor portion 10 and the sealing layer 20 in the thickness direction by drilling, laser processing, or the like. Then, the inner wall surface of the second through-hole 32 is metallized using a metal material containing a low-resistance metal such as copper, gold, or silver, thereby forming the second through-hole conductor 52. When forming the second through-hole conductor 52, the inner wall surface of the second through-hole 32 can be metallized using, for example, electroless copper plating or electrolytic copper plating, thereby facilitating processing. Furthermore, in addition to metallizing the inner wall surface of the second through-hole 32, a method of filling the second through-hole 32 with a metal material, a composite material of metal and resin, or the like can also be used.

[0154] An anode connection layer may be provided in the plane direction between the anode plate 11 and the second through-hole conductor 52. That is, the anode plate 11 and the second through-hole conductor 52 may be electrically connected via the anode connection layer.

[0155] By providing the anode connection layer between the anode plate 11 and the second through-hole conductor 52 in the planar direction, the anode connection layer functions as a barrier layer with respect to the anode plate 11, more specifically, with respect to the core portion 11A and the porous portion 11B. If the anode connection layer functions as a barrier layer with respect to the anode plate 11, dissolution of the anode plate 11 during treatment with a chemical solution for forming the second external electrode layer 82 and other external electrode layers can be suppressed, thereby suppressing the infiltration of the chemical solution into the capacitor portion 10, thereby easily improving reliability.

[0156] The anode connection layer preferably includes a layer mainly composed of nickel. In this case, damage to the metal (eg, aluminum) constituting the anode plate 11 is reduced, and thus the barrier properties of the anode connection layer against the anode plate 11 are likely to be improved.

[0157] Furthermore, an anode connection layer may not be provided between the anode plate 11 and the second through-hole conductor 52 in the plane direction. In this case, the second through-hole conductor 52 may be directly connected to the end surface of the anode plate 11 .

[0158] Examples of the constituent material of via conductor 70 include metal materials containing low-resistance metals such as silver, gold, and copper.

[0159] Via conductor 70 is formed by plating the inner wall surface of a through hole penetrating sealing layer 20 in the thickness direction with the aforementioned metal material, or by filling the through hole with a conductive paste and then performing a heat treatment.

[0160] The capacitor element of the present invention is not limited to the above-described embodiment, and various applications and modifications can be made to the structure, manufacturing conditions, etc. of the capacitor element within the scope of the present invention.

[0161] In the capacitor element of the present invention, one capacitor portion may be disposed inside the sealing layer, or a plurality of capacitor portions may be disposed.

[0162] The capacitor element of the present invention can be suitably used as a constituent material of a composite electronic component. Such a composite electronic component comprises, for example, the capacitor element of the present invention; an external electrode layer provided on the surface of the sealing layer of the capacitor element and electrically connected to the anode plate and cathode layer of the capacitor element; and an electronic component connected to the external electrode layer.

[0163] In a composite electronic component, the electronic component connected to the external electrode layer may be either a passive element or an active element. Both the passive element and the active element may be connected to the external electrode layer, or either the passive element or the active element may be connected to the external electrode layer. Furthermore, a composite of a passive element and an active element may be connected to the external electrode layer.

[0164] Examples of passive components include inductors, etc. Examples of active components include memories, GPUs (Graphical Processing Units), CPUs (Central Processing Units), MPUs (Micro Processing Units), and PMICs (Power Management ICs).

[0165] The capacitor element of the present invention has an overall sheet-like shape. Therefore, in a composite electronic component, the capacitor element can be treated like a mounting substrate, and electronic components can be mounted on the capacitor element. Furthermore, by making the electronic component mounted on the capacitor element sheet-like, the capacitor element and the electronic component can be connected in the thickness direction via through-hole conductors that penetrate each electronic component in the thickness direction. As a result, active and passive components can be constructed as a single integrated module.

[0166] For example, the capacitor element of the present invention can be electrically connected between a voltage regulator including a semiconductor active element and a load to which a converted DC voltage is supplied, thereby forming a switching regulator.

[0167] In the composite electronic component, after forming a circuit layer on any one surface of the capacitor matrix sheet on which a plurality of capacitor elements of the present invention are further arranged, passive elements or active elements may be connected thereto.

[0168] Alternatively, the capacitor element of the present invention may be placed in a cavity pre-formed in the substrate, embedded with resin, and then a circuit layer may be formed on the resin. Alternatively, other electronic components (passive or active) may be mounted in other cavities of the substrate.

[0169] Alternatively, the capacitor element of the present invention may be mounted on a smooth carrier such as a wafer or glass, the outer layer may be formed with resin, and then the circuit layer may be formed, which may then be connected to passive or active elements.

[0170] This specification discloses the following contents.

[0171] <1>

[0172] A capacitor element, wherein:

[0173] The capacitor element has:

[0174] The capacitor portion includes an anode plate having a porous portion on at least one main surface of a core portion, a dielectric layer provided on a surface of the porous portion, and a cathode layer provided on a surface of the dielectric layer; and

[0175] a sealing layer provided so as to cover the capacitor portion;

[0176] The cathode layer includes a solid electrolyte layer provided on the surface of the dielectric layer.

[0177] The solid electrolyte layer contains a conductive polymer.

[0178] The sealing layer contains insulating resin and flat inorganic filler.

[0179] In the sealing layer located at a portion covering the capacitor portion, the flat inorganic filler is oriented in a plane direction perpendicular to the thickness direction.

[0180] <2>

[0181] The capacitor element according to <1>,

[0182] The capacitor element further includes a first through-hole conductor provided on at least an inner wall surface of a first through-hole penetrating the capacitor portion and the sealing layer in the thickness direction and electrically connected to the cathode layer.

[0183] The sealing layer is filled between the end surface of the anode plate and the first through-hole conductor.

[0184] In the sealing layer located in a portion filling a space between the end surface of the anode plate and the first through-hole conductor, the flat inorganic filler is oriented in the thickness direction.

[0185] <3>

[0186] The capacitor element according to <2>,

[0187] The major axis of the flat inorganic filler is 1 / 5 or less of the diameter of the first through-hole conductor.

[0188] <4>

[0189] The capacitor element according to <2> or <3>, wherein

[0190] In the sealing layer located between the end surface of the anode plate and the first through-hole conductor, the orientation ratio of the flat inorganic filler in the thickness direction is 70% or more at the center in the thickness direction of the first through-hole conductor.

[0191] <5>

[0192] The capacitor element according to any one of <2> to <4>,

[0193] A first resin filling portion containing an insulating resin and a flat inorganic filler is provided inside the first through-hole conductor provided on the inner wall surface of the first through-hole.

[0194] In the first resin-filled portion, the flat inorganic filler is oriented in the thickness direction.

[0195] <6>

[0196] The capacitor element according to <5>,

[0197] In the first resin-filled portion, an orientation rate of the flat inorganic filler in the thickness direction is 70% or more at the center of the first through-hole conductor in the thickness direction.

[0198] <7>

[0199] The capacitor element according to any one of <1> to <6>,

[0200] The capacitor element further includes a second through-hole conductor provided on at least an inner wall surface of a second through-hole penetrating the capacitor portion and the sealing layer in the thickness direction and electrically connected to the anode plate.

[0201] The second through-hole conductor is electrically connected to the anode plate at an inner wall surface of the second through-hole.

[0202] <8>

[0203] The capacitor element according to <7>, wherein

[0204] A second resin filling portion containing an insulating resin and a flat inorganic filler is provided inside the second through-hole conductor provided on the inner wall surface of the second through-hole.

[0205] In the second resin-filled portion, the flat inorganic filler is oriented in the thickness direction.

[0206] <9>

[0207] The capacitor element according to <8>,

[0208] In the second resin-filled portion, an orientation rate of the flat inorganic filler in the thickness direction is 70% or more at the center of the second through-hole conductor in the thickness direction.

[0209] <10>

[0210] The capacitor element according to any one of <1> to <9>,

[0211] A plurality of capacitor portions are arranged inside the sealing layer.

[0212] Adjacent capacitor portions are separated from each other by through grooves penetrating the capacitor portions in the thickness direction.

[0213] The through groove is filled with the sealing layer.

[0214] In the sealing layer located at a portion filling the through-groove, the flat inorganic filler is oriented in the thickness direction.

[0215] <11>

[0216] The capacitor element according to <10>,

[0217] The major diameter of the flat inorganic filler is 1 / 3 or less of the width of the through-groove.

[0218] <12>

[0219] The capacitor element according to <10> or <11>, wherein

[0220] In the sealing layer located at a portion filling the through-groove, an orientation ratio of the flat inorganic filler in the thickness direction is 70% or more at a center in the thickness direction of the through-groove.

[0221] <13>

[0222] The capacitor element according to any one of <1> to <12>,

[0223] The flat inorganic filler contained in the sealing layer includes one or more of inorganic glass and a silicic acid compound.

[0224] <14>

[0225] The capacitor element according to any one of <1> to <13>,

[0226] The insulating resin contained in the sealing layer includes epoxy resin or phenol resin.

[0227] <15>

[0228] The capacitor element according to any one of <1> to <14>,

[0229] The sealing layer includes a first sealing layer covering the capacitor portion and a second sealing layer covering the first sealing layer.

[0230] At least the first sealing layer among the first sealing layer and the second sealing layer contains the flat inorganic filler.

[0231] Example

[0232] Hereinafter, examples will be described that more specifically disclose the capacitor element of the present invention. However, the present invention is not limited to these examples.

[0233] [Preparation of Resin Paste Containing Inorganic Filler]

[0234] 30% by volume of an inorganic filler was added to 70% by volume of a thermosetting epoxy resin and mixed with a centrifugal stirrer to obtain a paste. The viscosity of the obtained paste was adjusted with ethanol.

[0235] Specifically, mica powder was used as a flat inorganic filler. Mica powder with an average particle size of 3μm, 5μm, or 10μm was prepared and dispersed in epoxy resin using a centrifugal mixer. Ethanol was used to adjust the viscosity to 2000 cP (2 Pa·s) to prepare a resin paste containing the inorganic filler. For comparison, a resin paste containing an inorganic filler was prepared that also contained silica particles with an average particle size of 3μm as a spherical inorganic filler.

[0236] [Fabrication of capacitor elements]

[0237] The paste is printed across the gaps between the capacitor's conductive layers (Cu internal electrode layers), dried, and solidified. A laser is then used to create through-holes for the via conductors, which are electrically connected to the cathode layer. The paste is then injected into the through-holes using a printing method. This method uses a printing method that combines suction from the bottom surface and pressure on the coating surface to promote resin fluidity.

[0238] After the paste solidified, a laser was used to cut through each capacitor section along the X-axis to form through-grooves. The paste was then printed along these through-grooves and solidified. Furthermore, a laser was used to cut through each capacitor section along the Y-axis to form through-grooves. The paste was then printed and solidified in the same manner as for the X-axis. A 30μm thick epoxy resin film was then thermally fused to form the capacitor element.

[0239] In the resulting capacitor element, a first through-hole conductor electrically connected to the cathode layer and a second through-hole conductor electrically connected to the anode plate are formed. Furthermore, via conductors reaching the Cu internal electrode layer are formed at predetermined locations using a laser. Subsequently, electroless Cu plating, electrolytic Cu plating, and pattern etching are performed to form the external electrode layer.

[0240] The diameters of the first and second via conductors are set to 50μm, 70μm, 100μm, or 120μm, and the minimum width of the through-groove is set to 15μm, 30μm, or 45μm. Wider through-grooves separating the capacitors provide better insulation, but this increases laser processing time and energy usage, so the upper limit is 30μm.

[0241] [Characteristics Evaluation of Capacitor Elements]

[0242] A capacitor element having first and second through-hole conductors with a diameter of 120 μm and a through-groove with a width of 30 μm was placed in air at 150° C., and its high-temperature life characteristics were evaluated.

[0243] Figure 6 This is a graph showing the temporal change in ESR (ESR ratio) at 100 kHz. Figure 7This is a graph showing the temporal change (ΔCs) of electrostatic capacitance at 120 kHz.

[0244] according to Figure 6 and Figure 7 It was confirmed that when the sealing layer is formed using an insulating resin containing a flat inorganic filler (mica), the ESR of the capacitor element is less likely to increase, and the electrostatic capacitance is less likely to decrease, compared to when the sealing layer is formed using an insulating resin containing a spherical inorganic filler (silica). This result is believed to be due to the fact that by reducing the permeation of oxygen and moisture during the processing process, the decomposition and degradation of the conductive polymer in the solid electrolyte layer is suppressed.

[0245] [Evaluation of printing status]

[0246] The printed state of the inorganic filler-containing resin paste was evaluated when the diameter of the first through-hole conductor or the width of the through-groove was changed. The results are shown in Table 1.

[0247] [Table 1]

[0248]

[0249] Table 1 confirms that if the flat inorganic filler (mica) is too large relative to the width of the through-groove, the resin paste is likely to clog. In Table 1, "many unfilled areas" means a void ratio of 10% or greater, as determined by cross-sectional exposure. Similarly, "some unfilled areas" means a void ratio of less than 10%, and "good" means a void ratio of less than 3%.

[0250] [Evaluation of leakage current]

[0251] The insulation properties of the sealing layer filled around the first through-hole conductor were evaluated by measuring the leakage current between the anodes and cathodes of each capacitor unit. The insulation properties of the sealing layer filled in the through-groove were evaluated by measuring the leakage current between the anodes of adjacent capacitor units. The results are shown in Table 2. In addition, in cases where the printing state of the paste was particularly poor and there were many unfilled parts, the leakage current was not measured and is recorded as "-" in Table 2. In the leakage current measurement, DC2V was applied to the capacitor element, and the current flowing in the capacitor unit after 2 minutes was measured. (The benchmark is a current value of less than 2μA, which is converted into an insulation resistance of more than 1MΩ.)

[0252] [Table 2]

[0253]

[0254] Table 2 confirms that in a sealing layer using a spherical inorganic filler (silicon dioxide), as the width of the through-groove decreases, leakage current increases and insulation decreases. On the other hand, in a sealing layer using a flat inorganic filler (mica), if the distance between the end face of the anode plate and the first through-hole conductor is too small relative to the particle size of the inorganic filler, leakage current increases and insulation decreases.

[0255] As the effect of flat inorganic filler, it is believed that compared with spherical inorganic filler, leakage current is reduced and insulation improves. Even if it is an inorganic filler with insulation, it is also easy to flow surface current on its surface. Usually, the longer the surface distance is, the less likely the surface current is to flow. Thus, it is believed that the sealing layer of the flat inorganic filler having a surface distance longer than that of the spherical inorganic filler can guarantee insulation more highly.

[0256] Description of Reference Numerals

[0257] 1. Capacitor element; 10. Capacitor portion; 11. Anode plate; 11A. Core portion; 11B. Porous portion; 12. Cathode layer; 12A. Solid electrolyte layer; 12B. Conductor layer; 13. Dielectric layer; 20. Sealing layer; 21. First sealing layer; 22. Second sealing layer; 25. Insulating shielding layer; 30. Through-groove; 31. First through-hole; 32. Second through-hole; 41. Insulating resin; 42. Flat inorganic filler; 51. First through-hole conductor; 52. Second through-hole conductor; 61. First resin-filled portion; 62. Second resin-filled portion; 70. Via conductor; 81. First external electrode layer; 82. Second external electrode layer; D 51 , the diameter of the first through-hole conductor; W 30 , the width of the through groove.

Claims

1. A capacitor element, wherein: The capacitor element has: The capacitor portion includes an anode plate having a porous portion on at least one main surface of a core portion, a dielectric layer provided on a surface of the porous portion, and a cathode layer provided on a surface of the dielectric layer; as well as a sealing layer provided so as to cover the capacitor portion; The cathode layer includes a solid electrolyte layer provided on the surface of the dielectric layer, The solid electrolyte layer contains a conductive polymer, The sealing layer contains an insulating resin and a flat inorganic filler. In the sealing layer located at a portion covering the capacitor portion, the flat inorganic filler is oriented in a plane direction perpendicular to the thickness direction.

2. The capacitor element according to claim 1, wherein The capacitor element further includes a first through-hole conductor provided on at least an inner wall surface of a first through-hole penetrating the capacitor portion and the sealing layer in the thickness direction and electrically connected to the cathode layer. The sealing layer is filled between the end surface of the anode plate and the first through-hole conductor. In the sealing layer located in a portion filling a space between the end surface of the anode plate and the first through-hole conductor, the flat inorganic filler is oriented in the thickness direction.

3. The capacitor element according to claim 2, wherein The major axis of the flat inorganic filler is 1 / 5 or less of the diameter of the first through-hole conductor.

4. The capacitor element according to claim 2 or 3, wherein In the sealing layer located between the end surface of the anode plate and the first through-hole conductor, the orientation ratio of the flat inorganic filler in the thickness direction is 70% or more at the center of the first through-hole conductor in the thickness direction.

5. The capacitor element according to any one of claims 2 to 4, wherein A first resin filling portion containing an insulating resin and a flat inorganic filler is provided inside the first through-hole conductor provided on the inner wall surface of the first through-hole. In the first resin-filled portion, the flat inorganic filler is oriented in the thickness direction. The capacitor element according to claim 5 , wherein In the first resin-filled portion, at the center of the first through-hole conductor in the thickness direction, an orientation rate of the flat inorganic filler in the thickness direction is 70% or more.

7. The capacitor element according to any one of claims 1 to 6, wherein The capacitor element further includes a second through-hole conductor provided on at least an inner wall surface of a second through-hole penetrating the capacitor portion and the sealing layer in the thickness direction and electrically connected to the anode plate. The second through-hole conductor is electrically connected to the anode plate at an inner wall surface of the second through-hole.

8. The capacitor element according to claim 7, wherein A second resin filling portion containing an insulating resin and a flat inorganic filler is provided inside the second through-hole conductor provided on the inner wall surface of the second through-hole. In the second resin-filled portion, the flat inorganic filler is oriented in the thickness direction.

9. The capacitor element according to claim 8, wherein In the second resin-filled portion, at the center of the second through-hole conductor in the thickness direction, an orientation rate of the flat inorganic filler in the thickness direction is 70% or more.

10. The capacitor element according to any one of claims 1 to 9, wherein A plurality of capacitor portions are arranged inside the sealing layer. Adjacent capacitor portions are separated from each other by through grooves penetrating the capacitor portions in the thickness direction. The through groove is filled with the sealing layer, In the sealing layer located at a portion filling the through-groove, the flat inorganic filler is oriented in the thickness direction. The capacitor element according to claim 10 , wherein The major diameter of the flat inorganic filler is 1 / 3 or less of the width of the through groove.

12. The capacitor element according to claim 10 or 11, wherein In the sealing layer located at a portion filling the through-groove, an orientation ratio of the flat inorganic filler in the thickness direction is 70% or more at the center of the through-groove in the thickness direction.

13. The capacitor element according to any one of claims 1 to 12, wherein The flat inorganic filler contained in the sealing layer includes one or more of inorganic glass and a silicic acid compound.

14. The capacitor element according to any one of claims 1 to 13, wherein The insulating resin contained in the sealing layer includes epoxy resin or phenol resin.

15. The capacitor element according to any one of claims 1 to 14, wherein The sealing layer includes a first sealing layer covering the capacitor portion and a second sealing layer covering the first sealing layer. At least the first sealing layer among the first sealing layer and the second sealing layer contains the flat inorganic filler.

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