Solid electrolytic capacitor

Abstract

A solid electrolytic capacitor 1 comprises: an element laminated body 100; a first external electrode 141; and a second external electrode 142. In the element laminated body 100, first layers 110 and second layers 120 are laminated via an adhesive resin 15. The first layers 110 each comprise: a valve metal substrate 11 having a dielectric layer 16 formed on a surface thereof; and a solid electrolyte layer 13 provided on the dielectric layer 16. The second layers 120 each comprise a metal foil sheet 21. Further, among first end surface E 101 and second end surface E 102 facing each other in the lengthwise direction in the element laminated body 100, the first end surface E 101 exposes the metal foil sheet 21 and a first sealing part 131, the second end surface E 102 exposes the valve metal substrate 11 and a second sealing part 132. The first external electrode 141 is provided to the first end surface E 101 of the element laminated body 100 and is connected to the metal foil sheet 21. The second external electrode 142 is provided to the second end surface E 102 of the element laminated body 100 and is connected to the valve metal substrate 11. The first sealing part 131 has first columnar portions 131a which penetrate through the metal foil sheets 21 along the lamination direction and first belt-like portions 131b which are provided between the metal foil sheets 21 and which connect the first columnar portions 131a. The second sealing part 132 has second columnar portions 132a which penetrate through the valve metal substrates 11 along the lamination direction, and second belt-like portions 132b that are provided between the valve metal substrates 11 and that connect the second columnar portions 132a. The adhesive resin 15 includes a smaller amount of filler than the first sealing part 131 and the second sealing part 132, and is provided in the element laminated body 100, in at least one of a first region between the metal foil sheet 21 and the corresponding first columnar portion 131a, a second region between the valve metal substrate 11 and the corresponding first belt-like portion 131b, a third region between the valve metal substrate 11 and the corresponding second columnar portion 132a, and a fourth region between the metal foil sheet 21 and the corresponding second belt-like portion 132b.

Description

Technical Field

[0001] The present invention relates to a solid electrolytic capacitor.

Background Art

[0002] Patent Document 1 discloses a method for manufacturing a solid electrolytic capacitor including steps of: (A) preparing a first sheet; (B) preparing a second sheet; (C) coating the first sheet with an insulating material; (D) forming a conductor layer on the first sheet; (E) producing a laminated sheet; (F) producing a laminated block body; (G) producing a plurality of element laminate bodies by cutting the laminated block body; and (H) forming a first external electrode and a second external electrode, and a solid electrolytic capacitor manufactured by the manufacturing method.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the solid electrolytic capacitor manufactured by the manufacturing method disclosed in Patent Document 1, a capacitor element is formed by laminating a valve action metal substrate having a dielectric layer formed on its surface and a metal foil via a solid electrolyte layer, and the periphery of the capacitor element is sealed with a sealing material except for the connection portion with the external electrode. However, in such a structure, a gap may occur between the valve action metal substrate or the metal foil and the sealing material, resulting in a decrease in the sealing property of the solid electrolytic capacitor.

[0005] The present invention has been made to solve the above problems, and an object thereof is to provide a solid electrolytic capacitor having excellent sealing properties.

Means for Solving the Problems

[0006] The solid electrolytic capacitor of the present invention is a solid electrolytic capacitor including an element laminate, a first external electrode, and a second external electrode. In the element laminate, a first layer and a second layer are laminated via an adhesive resin. The first layer includes a valve action metal substrate having a dielectric layer formed on its surface and a solid electrolyte layer provided on the dielectric layer. The second layer is made of a metal foil. Further, in the element laminate, among the first end face and the second end face that face each other in the length direction, the metal foil and the first sealing portion are exposed on the first end face, and the valve action metal substrate and the second sealing portion are exposed on the second end face. The first external electrode is provided on the first end face of the element laminate and is connected to the metal foil. The second external electrode is provided on the second end face of the element laminate and is connected to the valve action metal substrate. The first sealing portion has a first columnar portion that penetrates the metal foil in the lamination direction and a first strip portion that is provided between the metal foils and connects between the first columnar portions. The second sealing portion has a second columnar portion that penetrates the valve action metal substrate in the lamination direction and a second strip portion that is provided between the valve action metal substrates and connects between the second columnar portions. The adhesive resin has fewer fillers than the first sealing portion and the second sealing portion, and exists in at least one of a first region between the metal foil and the first columnar portion, a second region between the valve action metal substrate and the first strip portion, a third region between the valve action metal substrate and the second columnar portion, and a fourth region between the metal foil and the second strip portion inside the element laminate.

Advantages of the Invention

[0007] According to the present invention, a solid electrolytic capacitor excellent in sealing performance can be provided.

Brief Description of the Drawings

[0008]

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DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the solid electrolytic capacitor of the present invention will be described. However, the present invention is not limited to the following configurations, and can be appropriately modified and applied without changing the gist of the present invention. In addition, a combination of two or more of the individual desirable configurations described below is also the present invention.

[0010] (First Embodiment) [Solid Electrolytic Capacitor] FIG. 1 is a cross-sectional view schematically showing an example of a solid electrolytic capacitor according to a first embodiment of the present invention. The solid electrolytic capacitor 1 shown in FIG. 1 includes an element laminate 100, a first external electrode 141, and a second external electrode 142.

[0011] In the element laminate 100, as shown in FIG. 1, a valve action metal substrate 11 having a porous portion (not shown) on its surface, a dielectric layer 12 formed on the surface of the porous portion, and a solid electrolyte layer 13 provided on the dielectric layer 12. A first layer 110 and a second layer 120 made of a metal foil 21 are laminated via an adhesive resin (not shown).

[0012] A mask layer (not shown) is provided around the solid electrolyte layer 13 on the dielectric layer 12, and an adhesive resin is provided on the mask layer (between the mask layer and the metal foil 21) in the same planar shape as the mask layer. In addition, a conductor layer (not shown) is provided between the solid electrolyte layer 13 and the metal foil 21.

[0013] Furthermore, in the element laminate 100, among the first end face E101 and the second end face E102 that face each other in the length direction (L direction) orthogonal to the lamination direction (T direction), the metal foil 21 and the first sealing portion 131 are exposed on the first end face E101, and the valve-acting metal substrate 11 and the second sealing portion 132 are exposed on the second end face E102. Although the dielectric layer 12 is also exposed on the second end face E102 of the element laminate 100, in the following description, it is simply described as "the valve-acting metal substrate 11 and the second sealing portion 132 are exposed".

[0014] The first external electrode 141 is provided on the first end face E101 of the element laminate 100 and is connected to the metal foil 21, and the second external electrode 142 is provided on the second end face E102 of the element laminate 100 and is connected to the valve-acting metal substrate 11.

[0015] FIG. 2A is a perspective view of the solid electrolytic capacitor shown in FIG. 1 as viewed from the first end face side. FIG. 2B is a perspective view of the solid electrolytic capacitor shown in FIG. 1 as viewed from the second end face side. FIG. 3 is an enlarged plan view of the first end face of the element laminate constituting the solid electrolytic capacitor shown in FIG. 1. FIG. 4 is an enlarged plan view of the second end face of the element laminate constituting the solid electrolytic capacitor shown in FIG. 1. Note that FIG. 1 is a cross-sectional view taken along line A-A of the element laminate shown in FIG. 2A.

[0016] As shown in FIGS. 1, 2A, and 2B, the element laminate 100 has a first main surface M101 and a second main surface M102 that face each other in the lamination direction (T direction), a first end face E101 and a second end face E102 that face each other in the length direction (L direction) orthogonal to the lamination direction, and a first side surface S101 and a second side surface S102 that face each other in the width direction (W direction) orthogonal to the lamination direction and the length direction.

[0017] In addition, the element laminate 100 further includes a third sealing portion 133 that covers each of the main surfaces M101, M102, and a fourth sealing portion 134 that covers each of the side surfaces S101, S102. Note that the third sealing portion 133 may cover at least one of the main surfaces M101 and / or M102 of the element laminate 100.

[0018] As shown in FIGS. 2A and 3, the first sealing portion 131 has a first columnar portion 131a that penetrates the metal foil 21 in the stacking direction, and a first strip portion 131b that is provided between the metal foils 21 and connects between the first columnar portions 131a.

[0019] As shown in FIGS. 2B and 4, the second sealing portion 132 has a second columnar portion 132a that penetrates the valve-acting metal base 11 in the stacking direction, and a second strip portion 132b that is provided between the valve-acting metal bases 11 and connects between the second columnar portions 132a.

[0020] As shown in FIG. 2A, the metal foil 21 has a rectangular shape with a plurality (however, the same number for the plurality of stacked metal foils 21) of notches 21a provided on one side on the first end face E101 side. Similarly, as shown in FIG. 2B, the valve-acting metal base 11 (and the dielectric layer 12) has a rectangular shape with a plurality (however, the same number for the plurality of stacked valve-acting metal bases 11) of notches 11a provided on one side on the second columnar portion 132a side. The notches 11a and 21a are preferably arranged at equal intervals in the width direction. Note that although both the notches 11a and 21a are semicircular, each shape is not particularly limited.

[0021] FIG. 5A is a diagram schematically showing a state in which the inside of the element laminate shown in FIG. 3 is seen through from the first end face side. FIG. 5B is a cross-sectional view taken along line X1-X1 of the element laminate shown in FIG. 5A. FIG. 5C is a cross-sectional view taken along line X2-X2 of the element laminate shown in FIG. 5A. FIG. 6A is a diagram schematically showing a state in which the inside of the element laminate shown in FIG. 4 is seen through from the second end face side. FIG. 6B is a cross-sectional view taken along line X3-X3 of the element laminate shown in FIG. 6A. FIG. 6C is a cross-sectional view taken along line X4-X4 of the element laminate shown in FIG. 6A.

[0022] The adhesive resin 15 that bonds the first layer 110 and the second layer 120 is present in the first region between the metal foil 21 and the first columnar portion 131a inside the element laminate 100 (see FIGS. 5A and 5B), and is present in the second region between the valve-acting metal substrate 11 and the first strip portion 131b (see FIGS. 5A and 5C). Further, the adhesive resin 15 is present in the third region between the valve-acting metal substrate 11 and the second columnar portion 132a inside the element laminate 100 (see FIGS. 6A and 6C), and is present in the fourth region between the metal foil 21 and the second strip portion 132b (see FIGS. 6A and 6B). Furthermore, the adhesive resin 15 has fewer fillers than the first sealing portion 131 and the second sealing portion 132, that is, it is resin-rich. Therefore, the adhesive resin 15 has higher flexibility than the first sealing portion 131 and the second sealing portion 132. Thus, inside the element laminate 100, by interposing the highly flexible adhesive resin 15 between the metal foil 21 and the first sealing portion 131 and between the valve-acting metal substrate 11 and the second sealing portion 132, the generation of gaps between them can be suppressed. Therefore, the sealing performance of the solid electrolytic capacitor 1 is improved.

[0023] Here, "the adhesive resin is present in the first region" means that the adhesive resin is present in at least a part of at least one first region. The same applies when the adhesive resin is present in the second region, the third region, or the fourth region.

[0024] Also, whether "the adhesive resin has fewer fillers than the first sealing portion" can be confirmed, for example, by observing an arbitrary cross-section of the solid electrolytic capacitor (however, a cross-section where the adhesive resin and the first sealing portion are exposed; the same applies hereinafter). Also, the accuracy of confirmation may be improved by taking the average of the results obtained by changing the observation location at an arbitrary plurality of cross-sections of the solid electrolytic capacitor. Furthermore, by performing elemental mapping on the cross-section with SEM-EDX and clarifying the target elements of the adhesive resin and the first sealing portion and examining the difference based on the mapping area of the metal components (such as Si, Al, etc.) different from the resin components (C, O, H) around the adhesive resin and the signal intensity of EDX, the accuracy of confirmation can also be improved. Whether "the adhesive resin has fewer fillers than the second sealing portion" can be confirmed in the same manner.

[0025] Note that the adhesive resin 15 may be present in at least one of the first region, the second region, the third region, and the fourth region inside the element laminate 100.

[0026] However, from the perspective of sealing performance, it is preferable that the adhesive resin 15 is present in at least one of the first region and the third region inside the element laminate 100, and more preferably, it is present in the first region and the third region.

[0027] When the adhesive resin 15 is present in the first region, the adhesive resin 15 will be present between the end face constituting at least one notch portion 21a of at least one metal foil 21 and the first columnar portion 131a. Also, when the adhesive resin 15 is present in the third region, the adhesive resin 15 will be present between the end face constituting at least one notch portion 11a of at least one valve-acting metal substrate 11 and the second columnar portion 132a.

[0028] The metal foil 21 has an end face 21b facing the first columnar portion 131a (i.e., the end face constituting the notch portion 21a) (see FIGS. 5A and 5B), and the valve-acting metal substrate 11 has an end face 11b facing the second columnar portion 132a (i.e., the end face constituting the notch portion 11a) (see FIGS. 6A and 6C). The end face 21b and the end face 11b are located inside the element laminate 100 and are end faces that are not exposed to the first end face E101 and the second end face E102, respectively.

[0029] From the viewpoint of sealing properties, it is preferable that the adhesive resin 15 covers the entire end face 21b of the metal foil 21 (see FIGS. 5A and 5B, particularly the central end face 21b in FIG. 5B), and it is preferable that the adhesive resin 15 covers the entire end face 11b of the valve-acting metal substrate 11 (see FIGS. 6A and 6C, particularly the central end face 11b in FIG. 6C). At this time, "the adhesive resin 15 covers the entire end face 21b of the metal foil 21" means that the adhesive resin 15 covers the entire end face 21b of at least one metal foil 21. The same applies when the adhesive resin 15 covers the entire end face 11b of the valve-acting metal substrate 11.

[0030] Note that the adhesive resin 15 may cover only one of the entire end face 21b of the metal foil 21 and the entire end face 11b of the valve-acting metal substrate 11.

[0031] FIG. 7 is a plan view showing a modified example of the first end face shown in FIG. 3. FIG. 8 is a plan view showing a modified example of the second end face shown in FIG. 4.

[0032] Next, as shown in FIG. 7, the resin 15 may be exposed from the inside of the element laminate 100 to the first end face E101, or as shown in FIG. 8, it may be exposed from the inside of the element laminate 100 to the second end face E102. When the laminated block body is separated into individual pieces of the element laminate 100, shear stress leading to interfacial peeling is generated on the first end face E101 and the second end face E102, but the shear stress can be relaxed by the exposed adhesive resin 15. Therefore, it is possible to suppress the occurrence of a peeling interface (gap) between the metal foil 21 and the first sealing portion 131, and it is possible to suppress the occurrence of a peeling interface (gap) between the valve action metal substrate 11 and the dielectric layer 12 and the second sealing portion 132. Accordingly, the sealing performance of the solid electrolytic capacitor 1 is further improved. Further, when the first external electrode 141 and the second external electrode 142 are formed by plating, it is possible to prevent the plating solution from entering through the gap, so that LC defects due to precipitation of metal ions in the plating solution that has entered the inside of the element laminate 100 can be reduced. Furthermore, since it is possible to prevent moisture in the air from entering through the gap, corrosion of the metal foil 21 and the valve action metal substrate 11 due to moisture can be reduced, and LC defects can be improved.

[0033] Note that the adhesive resin 15 may be exposed only from the inside of the element laminate 100 to either one of the first end face E101 and the second end face E102. Further, when the adhesive resin 15 is exposed to the first end face E101 and / or the second end face E102, usually, the adhesive resin 15 is exposed only from the inside of the element laminate 100 to at least a part of either one of the first end face E101 and the second end face E102.

[0034] From the viewpoint of sealing performance, it is preferable that the adhesive resin 15 does not contain a filler. By not containing a filler, the adhesive strength of the adhesive resin 15 is improved, and generation of gaps inside the element laminate 100 can be more effectively suppressed. This is because the filler does not have an adhesive function, and only the resin has an adhesive function.

[0035] In addition, the Poisson's ratio of the adhesive resin 15 is preferably 0.3 or more, and more preferably 0.4 or more. As a result, the deformation of the adhesive resin 15 increases, so that the shear stress during the above-mentioned singulation by cutting can be more effectively relieved.

[0036] The Poisson's ratio of the adhesive resin 15 can be measured with a microhardness tester. That is, a indenter (for example, a triangular pyramid indenter made of diamond) is pressed into the target site (adhesive resin 15), and the Poisson's ratio can be measured from the elastic recovery behavior during unloading.

[0037] As shown in FIG. 2A, the metal foil 21 and the first sealing portion 131 are exposed on the first end face E101 of the element laminate 100. The sum A1 of the distances A11, A12, A13, and A14 at which the metal foil 21 is exposed on the first end face E101 per layer in the width direction is preferably smaller than the maximum width B1 of the metal foil 21.

[0038] On the other hand, as shown in FIG. 2B, the valve-acting metal substrate 11 and the second sealing portion 132 are exposed on the second end face E102 of the element laminate 100. The sum A2 of the distances A21, A22, A23, and A24 at which the valve-acting metal substrate 11 is exposed on the second end face E102 per layer in the width direction is preferably smaller than the maximum width B2 of the valve-acting metal substrate 11.

[0039] Considering the filling property of the sealing material, the widths of the first columnar portion 131a and the second columnar portion 132a are preferably as large as possible. However, the proportion of the metal foil 21 and the valve-acting metal substrate 11 exposed on the first end face E101 and the second end face E102 respectively decreases accordingly, resulting in an increase in ESR.

[0040] Therefore, the value of A1 / B1 is preferably 0.1 or more and 0.9 or less, and more preferably 0.5 or more. Also, the value of A2 / B2 is preferably 0.1 or more and 0.9 or less, and more preferably 0.5 or more.

[0041] Note that the value of A1 may be the same as or different from the value of A2. Similarly, the value of B1 may be the same as or different from the value of B2. Therefore, the value of A1 / B1 may be the same as or different from the value of A2 / B2.

[0042] As will be described later, the first sealing portion 131 and the second sealing portion 132 are formed by filling a sealing material into the through holes. Therefore, it is preferable that the first columnar portion 131a and the first strip portion 131b are integrally formed, and the second columnar portion 132a and the second strip portion 132b are integrally formed. Note that "being integrally formed" means that there is no interface at the boundary between the two.

[0043] In consideration of the filling property of the sealing material when forming the first sealing portion 131 and the second sealing portion 132, it is preferable that two or more first columnar portions 131a and two or more second columnar portions 132a are formed in the width direction, respectively. In this case, it is preferable that the first columnar portion 131a and the second columnar portion 132a are linearly provided from the first main surface M101 to the second main surface M102 of the element laminate 100, respectively.

[0044] The width of each of the columnar portions 131a and 132a is not particularly limited, but is preferably 10% or more and 70% or less with respect to the maximum width of the metal foil 21 or the valve-acting metal substrate 11. For example, when the maximum width of the metal foil 21 or the valve-acting metal substrate 11 is 3 mm, it is preferable to arrange three columnar portions with a width of 0.5 mm. In this case, the distance between the columnar portions is preferably 0.35 mm.

[0045] When two or more first columnar portions 131a and two or more second columnar portions 132a are formed, respectively, in consideration of the filling property of the sealing material, it is preferable that these columnar portions are formed at equal intervals. Note that "equal intervals" does not necessarily mean that the width of the strip portion located between the columnar portions is exactly the same length, and it may be within a range of about 3% or less.

[0046] The width of the strip located between the columnar portions is not particularly limited, but it is preferably 10% or more and 70% or less with respect to the maximum width of the metal foil 21 or the valve-acting metal substrate 11.

[0047] The width of the strip not located between the columnar portions is preferably about the same as the width of the strip located between the columnar portions.

[0048] Also, as will be described later, in addition to the first sealing portion 131 and the second sealing portion 132, a third sealing portion 133 can be formed simultaneously. Therefore, the third sealing portion 133 covering at least one of the main surfaces M101 and / or M102 of the element laminate 100 is preferably formed integrally with the first sealing portion 131 and the second sealing portion 132.

[0049] In the solid electrolytic capacitor 1, the valve-acting metal substrate 11 and the metal foil 21 are connected via another conductor layer provided on the solid electrolyte layer 13. In this case, they may be connected via a conductive adhesive layer provided on the conductor layer. The conductor layer may be composed only of a carbon layer, may be composed only of a silver layer, or may be composed of two layers of a carbon layer as a base and a silver layer thereon.

[0050] Among them, it is preferable that a carbon layer is provided as the conductor layer on the solid electrolyte layer 13, the surface of the metal foil 21 is in direct contact with the carbon layer, and it is more preferable that the surface of the carbon-coated metal foil 21 is in direct contact with the carbon layer.

[0051] Also, for portions where the solid electrolyte layer 13, the conductor layer, or the conductive adhesive layer is not provided, it is preferable that the valve-acting metal substrate 11 and the metal foil 21 are connected via the adhesive resin 15.

[0052] [Manufacturing Method of Solid Electrolytic Capacitor] Hereinafter, an example of the manufacturing method of the solid electrolytic capacitor according to the present embodiment will be described step by step.

[0053] (A) Step of preparing the first sheet First, prepare the first sheet.

[0054] FIG. 9A is a perspective view schematically showing an example of the first sheet. FIG. 9B is an enlarged perspective view of a part of the first sheet shown in FIG. 9A. The first sheet 10 shown in FIGS. 9A and 9B has a plurality of element regions R11 (hereinafter referred to as the first element regions) and a plurality of element regions R12 (hereinafter referred to as the second element regions).

[0055] As shown in FIG. 9B, the first element region R11 is defined by a first end portion E11 and a second end portion E12 that are opposite in the length direction (L direction), and a first side portion S11 and a second side portion S12 that are opposite in the width direction (W direction) orthogonal to the length direction. The first element region R11 has a dimension in the length direction (L direction) that is larger than the dimension in the width direction (W direction). And one first through hole H1 is formed so as to straddle the first end portion E11 of the first element region R11 in the length direction, and a plurality of (three in FIG. 9B) second through holes H2 are formed so as to straddle the second end portion E12 of the first element region R11 in the length direction. The first through hole H1 is composed of one long hole having a width equal to or greater than the width of the first element region R11, and the second through holes H2 are composed of a plurality of substantially round holes having a width smaller than the width of the first element region R11.

[0056] On the other hand, the second element region R12 has the same shape as the first element region R11, but the directions of the first end portion E11 and the second end portion E12 are opposite to those of the first element region R11.

[0057] As shown in FIG. 9A, in the first sheet 10, the first element regions R11 and the second element regions R12 are alternately arranged in the length direction. As shown in FIG. 9B, the first element region R11 shares the first end portion E11 and the first through hole H1 with the adjacent second element region R12, and shares the second end portion E12 and the second through holes H2 with the other adjacent second element region R12.

[0058] Furthermore, as shown in FIG. 9A, in the first sheet 10, the first element regions R11 and the second element regions R12 are alternately arranged in the width direction. As shown in FIG. 9B, the first element region R11 shares the first side portion S11 with the adjacent second element region R12 and shares the second side portion S12 with the other adjacent second element region R12.

[0059] As shown in FIG. 9B, the first sheet 10 includes a valve-acting metal substrate 11 having a porous portion (not shown) on the surface, a dielectric layer 12 formed on the surface of the porous portion, and solid electrolyte layers 13 provided inside each element region on the dielectric layer 12. In the first sheet 10, the ends and sides of each element region are covered by a mask layer 14 made of an insulating material, and the solid electrolyte layer 13 is provided in the region surrounded by the mask layer 14.

[0060] In the first sheet 10 shown in FIG. 9B, the valve-acting metal substrate 11 has porous portions on both sides, the dielectric layer 12 is formed on the surface of each porous portion, and the solid electrolyte layer 13 is provided on the dielectric layer 12. However, when the second sheet is not laminated on one surface of the first sheet, it is not necessary to provide a solid electrolyte layer on the surface of the valve-acting metal substrate on the side where the second sheet (metal foil) is not laminated. In this case, a dielectric layer may not be formed on the surface of the valve-acting metal substrate on the side where the second sheet (metal foil) is not laminated, and a porous portion may not be formed either. Further, as the first sheet 10, one in which the valve-acting metal substrate 11 has a porous portion only on one side and the dielectric layer 12 is formed on the surface of the porous portion may be used.

[0061] The first sheet is preferably manufactured as follows. First, a valve-acting metal substrate 11 having a porous portion on the surface is prepared, and a dielectric layer 12 is formed on the surface of the porous portion. For example, when an aluminum foil is used as the valve-acting metal substrate, a dielectric layer made of an oxide film can be formed by performing an anodic oxidation treatment (also referred to as a chemical conversion treatment) on the surface of the aluminum foil in an aqueous solution containing ammonium adipate or the like.

[0062] The valve-acting metal substrate is made of a valve-acting metal that exhibits so-called valve action. Examples of the valve-acting metal include simple metals such as aluminum, tantalum, niobium, titanium, zirconium, etc., or alloys containing these metals. Among these, aluminum or an aluminum alloy is preferred.

[0063] The shape of the valve-acting metal substrate is preferably flat, and more preferably foil-shaped. Also, the porous part includes an etching layer formed on the surface of the valve-acting metal substrate, and a porous layer formed by printing and sintering on the surface of the valve-acting metal substrate. When the valve-acting metal is aluminum or an aluminum alloy, an etching layer is preferred, and when it is titanium or a titanium alloy, a porous layer is preferably used.

[0064] The thickness of the valve-acting metal substrate is not particularly limited, but the thickness of the part excluding the porous part is preferably 5 μm or more and 100 μm or less. Also, the thickness (thickness on one side) of the porous part is preferably 5 μm or more and 200 μm or less.

[0065] The dielectric layer formed on the surface of the porous part is porous reflecting the surface state of the porous part and has a fine uneven surface shape. The dielectric layer preferably consists of the oxide film of the above-mentioned valve-acting metal.

[0066] Also, from the viewpoint of improving production efficiency, as the valve-acting metal substrate with a dielectric layer formed on the surface, a formed foil that has been subjected to a forming treatment in advance may be used.

[0067] Next, it is preferable to form a mask layer 14 that covers the ends and sides of each element region. The mask layer is formed, for example, by applying a mask material made of an insulating material such as an insulating resin to the surface of the above-mentioned valve-acting metal substrate and solidifying or curing it by heating or the like. The application of the mask material is preferably performed by screen printing, dispenser coating, inkjet printing, or the like.

[0068] Examples of the insulating material for the mask layer include insulating resins such as polyphenyl sulfone resin, polyether sulfone resin, cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene·perfluoroalkyl vinyl ether copolymer, etc.), a composition composed of soluble polyimide siloxane and epoxy resin, polyimide resin, polyamideimide resin, and their derivatives or precursors.

[0069] Subsequently, a first through hole H1 is formed so as to straddle the first end portion E11 of each element region, and a second through hole H2 is formed so as to straddle the second end portion E12 of each element region. The first through hole and the second through hole are formed, for example, by laser processing, etching processing, punching processing, or the like.

[0070] Thereafter, a solid electrolyte layer 13 is formed inside each element region on the dielectric layer 12. At this time, it is preferable to form the solid electrolyte layer 13 in a region surrounded by the mask layer 14. For example, a solid electrolyte layer can be formed in a predetermined region by applying the following treatment liquid or dispersion liquid onto the dielectric layer by sponge transfer, screen printing, dispenser coating, inkjet printing, or the like.

[0071] The solid electrolyte layer is formed, for example, by a method of forming a polymer film such as poly(3,4-ethylenedioxythiophene) on the surface of the dielectric layer using a treatment liquid containing a monomer such as 3,4-ethylenedioxythiophene, or a method of applying a dispersion liquid of a polymer such as poly(3,4-ethylenedioxythiophene) on the surface of the dielectric layer and drying it. In addition, it is preferable to form the solid electrolyte layer by forming an inner layer that fills the pores (recesses) of the dielectric layer and then forming an outer layer that covers the dielectric layer.

[0072] Examples of materials constituting the solid electrolyte layer include conductive polymers such as polypyrroles, polythiophenes, and polyanilines. Among these, polythiophenes are preferred, and poly(3,4-ethylenedioxythiophene) called PEDOT is particularly preferred. Further, the above conductive polymer may contain a dopant such as polystyrene sulfonic acid (PSS).

[0073] Note that the first through-hole H1 and the second through-hole H2 may be formed before forming the mask layer 14, or may be formed after forming the solid electrolyte layer 13.

[0074] The size of the entire first sheet is determined by the size, shape, number, arrangement, production capacity, etc. of the element region, and is not particularly limited. The shape of the element region of the first sheet is not particularly limited, but is preferably rectangular. In this case, the first end portion and the second end portion may be shorter or longer than the first side portion and the second side portion.

[0075] The shape of the first through-hole is not particularly limited as long as it has a width equal to or greater than the width of the element region.

[0076] The shape, number, arrangement, etc. of the second through-hole are not particularly limited as long as it has a width smaller than the width of the element region, but in each element region, it is preferably formed in two or more in the width direction. When two or more second through-holes are formed, these through-holes are preferably formed at equal intervals. Note that if the width of each second through-hole is too small, it becomes difficult to fill the sealing material in the process described later. On the other hand, if the ratio of the total width of the second through-holes to the width of the element region is too large, the ratio of the valve action metal substrate exposed on the end face of the solid electrolytic capacitor becomes small, so the ESR tends to increase.

[0077] (B) Step of preparing the second sheet Separately, prepare a second sheet.

[0078] FIG. 10A is a perspective view schematically showing an example of the second sheet. FIG. 10B is an enlarged perspective view of a part of the second sheet shown in FIG. 10A. The second sheet 20 shown in FIGS. 10A and 10B has a plurality of element regions R21 (hereinafter referred to as the first element regions) and a plurality of element regions R22 (hereinafter referred to as the second element regions).

[0079] As shown in FIG. 10B, the first element region R21 is defined by a first end portion E21 and a second end portion E22 that are opposite to each other in the length direction (L direction), and a first side portion S21 and a second side portion S22 that are opposite to each other in the width direction (W direction) orthogonal to the length direction. A plurality of (three in FIG. 10B) third through holes H3 are formed so as to straddle the first end portion E21 of the first element region R21 in the length direction, and one fourth through hole H4 is formed so as to straddle the second end portion E22 of the first element region R21 in the length direction. The third through holes H3 are composed of a plurality of substantially round holes having a width smaller than the width of the first element region R21, and the fourth through hole H4 is composed of one long hole having a width equal to or greater than the width of the first element region R21.

[0080] On the other hand, the second element region R22 has the same shape as the first element region R21, but the directions of the first end portion E21 and the second end portion E22 are opposite to those of the first element region R21.

[0081] As shown in FIG. 10A, in the second sheet 20, the first element regions R21 and the second element regions R22 are alternately arranged in the length direction. As shown in FIG. 10B, the first element region R21 shares the first end portion E21 and the third through hole H3 with the adjacent second element region R22, and shares the second end portion E22 and the fourth through hole H4 with the other adjacent second element region R22.

[0082] Furthermore, as shown in FIG. 10A, in the second sheet 20, the first element regions R21 and the second element regions R22 are alternately arranged in the width direction. As shown in FIG. 10B, the first element region R21 shares the first side portion S21 with the adjacent second element region R22 and shares the second side portion S22 with the other adjacent second element region R22.

[0083] As shown in FIG. 10B, the second sheet 20 is made of a metal foil 21.

[0084] The second sheet is preferably manufactured as follows. First, a metal foil 21 is prepared.

[0085] The metal foil is preferably made of at least one metal selected from the group consisting of aluminum, copper, silver, and alloys mainly composed of these metals. When the metal foil is made of the above metals, the resistance value of the metal foil can be reduced, and the ESR can be reduced.

[0086] Also, as the metal foil, a metal foil with a carbon coating or a titanium coating formed on the surface by a film forming method such as sputtering or vapor deposition may be used.

[0087] The thickness of the metal foil is not particularly limited, but from the viewpoint of reducing the ESR, it is preferably 5 μm or more and 100 μm or less.

[0088] Preferably, a roughened surface is formed on the surface of the metal foil. When a roughened surface is formed on the surface of the metal foil, in addition to improving the adhesion between the metal foil and the solid electrolyte layer or the adhesion between the metal foil and other conductor layers, the contact area increases, so the ESR can be reduced. The method for forming the roughened surface is not particularly limited, and the roughened surface may be formed by etching or the like. Particularly when using aluminum, it is preferable to perform a carbon coating or a titanium coating on the surface that has been subjected to a roughening treatment (etching treatment) for reducing the resistance.

[0089] Also, a coating layer made of an anchor coating agent may be formed on the surface of the metal foil. When a coating layer made of an anchor coating agent is formed on the surface of the metal foil, the adhesion between the metal foil and the solid electrolyte layer or the adhesion between the metal foil and another conductor layer is improved, so that the ESR can be reduced.

[0090] Subsequently, a third through-hole H3 is formed so as to straddle the first end portion E21 of each element region, and a fourth through-hole H4 is formed so as to straddle the second end portion E22 of each element region. The third through-hole and the fourth through-hole are formed, for example, by laser processing, etching processing, punching processing, or the like.

[0091] The size of the entire second sheet is not particularly limited, but it is preferably the same as the size of the entire first sheet. The shape, number, and arrangement of the element regions of the second sheet are preferably the same as the shape, number, and arrangement of the element regions of the opposing first sheet.

[0092] The third through-hole is not particularly limited in terms of its shape, number, arrangement, etc., as long as it has a width smaller than the width of the element region, but in each element region, it is preferably formed in two or more in the width direction. When two or more third through-holes are formed, these through-holes are preferably formed at equal intervals. In addition, if the width of each third through-hole is too small, it becomes difficult to fill the sealing material in the subsequent process. On the other hand, if the ratio of the total width of the third through-holes to the width of the element region is too large, the ratio of the metal foil exposed on the end face of the solid electrolytic capacitor becomes small, so that the ESR tends to increase.

[0093] The shape of the fourth through-hole is not particularly limited as long as it has a width equal to or greater than the width of the element region.

[0094] (E) Step of manufacturing a laminated sheet A laminated sheet is produced by laminating a first sheet and a second sheet such that the first ends and the second ends of the respective element regions face each other. In the resulting laminated sheet, the first through-hole and the third through-hole, and the second through-hole and the fourth through-hole are respectively in communication in the lamination direction.

[0095] The second through-hole and the third through-hole are preferably linearly in communication from the first main surface to the second main surface of the laminated sheet.

[0096] When laminating the first sheet and the second sheet, the valve-acting metal substrate and the metal foil are connected via another conductor layer provided on the solid electrolyte layer. In this case, the valve-acting metal substrate and the metal foil may be connected via a conductive adhesive layer provided on the conductor layer.

[0097] Also, for portions where the solid electrolyte layer, the conductor layer, or the conductive adhesive layer is not provided, the valve-acting metal substrate and the metal foil are connected via an adhesive resin.

[0098] FIG. 11A is a perspective view schematically showing an example of the first sheet provided with an adhesive resin. FIG. 11B is an enlarged perspective view of a part of the first sheet shown in FIG. 11A. In FIGS. 11A and 11B, an adhesive resin (adhesive layer) 15 before solidification or curing is provided on the mask layer 14 of the first sheet 10 shown in FIGS. 9A and 9B.

[0099] The adhesive resin is an insulating adhesive containing at least a resin, and preferably does not contain a filler. Examples of the resin contained in the adhesive resin include epoxy resin, phenol resin, etc. Examples of the filler that may be contained in the adhesive resin include metal oxide particles such as silica particles and alumina particles.

[0100] When the resin contains a filler, it has less filler than the encapsulant described later. The content of the filler in the adhesive resin is not particularly limited, but is usually 0 wt% or more and 5 wt% or less, preferably 0 wt% or more and 15 wt% or less.

[0101] The adhesive resin is formed, for example, by applying an insulating adhesive before solidification or curing onto the mask layer and solidifying or curing it by heating or the like. The application of the insulating adhesive is preferably performed by screen printing, dispenser coating, inkjet printing, or the like.

[0102] Thus, this manufacturing method includes (C) a step of covering the first sheet with an insulating material. In step (C), the first end and the second end, and the first side and the second side of each element region of the first sheet are covered with an insulating material.

[0103] (C) The step of covering with an insulating material preferably includes a step of forming a mask layer and a step of forming an adhesive resin on the mask layer.

[0104] The adhesive resin may have the same components and viscosity as the mask layer, but preferably has different components and viscosity from the mask layer.

[0105] The height in the thickness direction of the combined mask layer and adhesive resin may be the same as the height in the thickness direction of the solid electrolyte layer, but is preferably greater than the height in the thickness direction of the solid electrolyte layer.

[0106] FIG. 12A is a perspective view schematically showing an example of the first sheet provided with the adhesive resin and the conductor layer. FIG. 12B is an enlarged perspective view of a part of the first sheet shown in FIG. 12A. In FIGS. 12A and 12B, an adhesive resin 15 before solidification or curing is provided on the mask layer 14 of the first sheet 10 shown in FIGS. 9A and 9B, and a conductor layer 16 is provided on the solid electrolyte layer 13.

[0107] Thus, this manufacturing method includes a step of forming a conductor layer on a first sheet. In the step (D), the conductor layer is formed on the solid electrolyte layer of the first sheet.

[0108] The conductor layer is preferably composed of only a carbon layer, but may be composed of only a silver layer, or may be composed of two layers, namely, a carbon layer as a base and a silver layer thereon. The carbon layer and the silver layer can be provided, for example, by applying a carbon paste and a silver paste, respectively.

[0109] When laminating the first sheet and the second sheet, it is preferable to place the metal foil on the layer located under the metal foil in a viscous state. Since the carbon paste, the silver paste, or the solid electrolyte layer before drying is in a viscous state, it is suitable for directly placing the metal foil. On the other hand, when the carbon layer, the silver layer, or the solid electrolyte layer as the layer located under the metal foil is dried, it becomes difficult to adhere the metal foil. Therefore, it is preferable to place the metal foil after providing a conductive adhesive layer.

[0110] Note that the conductor layer may be provided on the second sheet instead of the first sheet. In that case, it is preferable to form a dam resin on the second sheet in the same pattern as the adhesive resin 15, and form the conductor layer in the region surrounded by the dam resin.

[0111] The dam resin is obtained by solidifying or curing at least an insulating adhesive containing a resin, and preferably does not contain a filler. The dam resin can be formed using the insulating adhesive for forming the adhesive resin 15.

[0112] FIG. 13A is a perspective view schematically showing an example of a state before laminating the first sheet and the second sheet. FIG. 13B is a perspective view schematically showing an example of the laminated sheet. As shown in FIG. 13A, by alternately laminating the first sheet 10 and the second sheet 20 and solidifying or curing the adhesive resin 15, a laminated sheet 30 shown in FIG. 13B is obtained. The laminated sheet 30 has a first main surface M31 and a second main surface M32 that face each other in the lamination direction (T direction). In FIG. 13B, the adhesive resin 15 and the like are omitted (the same applies hereinafter), but by alternately laminating the first sheet 10 and the second sheet 20, the adhesive resin 15 is made to protrude from between the first sheet 10 and the second sheet 20 into the first through hole, the second through hole, the third through hole, and / or the fourth through hole. By appropriately setting the application amount and application position of the adhesive resin 15, it is possible to appropriately change the amount and position where the adhesive resin 15 protrudes.

[0113] In FIGS. 13A and 13B, an example is shown in which five first sheets 10 and five second sheets 20 are laminated, and the second sheet 20 is disposed on the first main surface M31 of the laminated sheet 30 and the first sheet 10 is disposed on the second main surface M32, but the number of first sheets and second sheets to be laminated is not particularly limited. Also, the number of first sheets and the number of second sheets may be the same or different. Therefore, either the first sheet or the second sheet may be disposed on the main surface of the laminated sheet. Further, when producing the laminated sheet, the first sheet and the second sheet may be laminated on a substrate made of a glass epoxy resin or the like.

[0114] (F) Step of producing a laminated block A laminated block is produced by filling a sealing material into the first through hole and the third through hole, and the second through hole and the fourth through hole, respectively, from at least one main surface side of the obtained laminated sheet.

[0115] As described above, in the laminated sheet, since the first through-hole and the third through-hole, and the second through-hole and the fourth through-hole communicate with each other in the lamination direction, a sealing material can be filled into each through-hole from the main surface side of the laminated sheet. As a result, in the obtained laminated block body, a first sealing portion that fills the first through-hole and the third through-hole, and a second sealing portion that fills the second through-hole and the fourth through-hole are formed.

[0116] The filling of the sealing material can be performed by a method such as a mold resin molding method. At this time, in addition to the first sealing portion and the second sealing portion, a third sealing portion that covers at least one main surface of the laminated sheet can be formed simultaneously. Thus, in the step of manufacturing the (F) laminated block, it is preferable to simultaneously perform the step of covering at least one main surface of the laminated sheet using the sealing material.

[0117] FIG. 14A is a perspective view schematically showing an example of a laminated block body. FIG. 14B is an exploded and enlarged perspective view of a part of the laminated block body shown in FIG. 14A. In the laminated block body 40 shown in FIG. 14A, by filling the first through-hole and the third through-hole, and the second through-hole and the fourth through-hole with a sealing material respectively, as shown in FIG. 14B, a first sealing portion 131 that fills the first through-hole H1 and the third through-hole H3, and a second sealing portion 132 that fills the second through-hole H2 and the fourth through-hole H4 are formed. Further, as shown in FIG. 14A, the laminated block body 40 further includes a third sealing portion 133 that covers each main surface.

[0118] The sealing material contains at least resin, and preferably contains resin and filler. Examples of the resin contained in the sealing material include epoxy resin, phenolic resin, etc. Examples of the filler contained in the sealing material include metal oxide particles such as silica particles and alumina particles.

[0119] When the sealing material contains a filler, there is more filler than the adhesive resin. The content of the filler in the sealing material is not particularly limited, but is usually 50% by weight or more and 95% by weight or less, preferably 80% by weight or more and 90% by weight or less.

[0120] When the sealing material contains a resin and a filler, from the viewpoint of ensuring the filling property of the sealing material, the maximum diameter of the filler is preferably smaller than the minimum diameters of the second through-hole and the third through-hole. Note that the diameter of the through-hole means the diameter when the cross-sectional shape is circular, and the maximum length passing through the center of the cross-section in other cases.

[0121] Also, when the sealing material contains a resin and a filler, from the viewpoint of ensuring the filling property of the sealing material, the maximum diameter of the filler is preferably smaller than the minimum thickness of the metal foil.

[0122] The maximum diameter of the filler diameter contained in the sealing material is preferably in the range of, for example, 20 μm or more and 50 μm or less.

[0123] (G) A step of producing a plurality of element laminate bodies by cutting the laminated block body The laminated block body is cut at the positions of the first end and the second end of each element region, and at the positions of the first side portion and the second side portion of each element region, thereby producing a plurality of element laminate bodies.

[0124] FIG. 15A is a plan view schematically showing the valve-acting metal substrate before cutting. FIG. 15B is a plan view schematically showing the valve-acting metal substrate after cutting. As shown in FIG. 15A, in the valve-acting metal substrate 11 constituting the first sheet included in the laminated block body, a first sealing portion 131 that fills a first through-hole H1 straddling the first end E11 of each element region, and a second sealing portion 132 that fills a second through-hole H2 straddling the second end E12 of each element region are formed.

[0125] Therefore, when the valve-acting metal substrate 11 is cut by dicing or the like so that the first sealing portion 131 and the second sealing portion 132 are separated on both sides at the positions of the first end portion E11 and the second end portion E12 of each element region, as shown in FIG. 15B, on the first end face E101 which is the cut surface on the first end portion E11 side, the first sealing portion 131 is exposed and the valve-acting metal substrate 11 is not exposed. On the other hand, on the second end face E102 which is the cut surface on the second end portion E12 side, the valve-acting metal substrate 11 and the second sealing portion 132 are exposed.

[0126] Also, when the valve-acting metal substrate 11 is cut by dicing or the like at the positions of the first side portion S11 and the second side portion S12 of each element region, as shown in FIG. 15B, the valve-acting metal substrate 11 is exposed on both cut surfaces.

[0127] FIG. 16A is a plan view schematically showing the metal foil before cutting. FIG. 16B is a plan view schematically showing the metal foil after cutting. As shown in FIG. 16A, in the metal foil 21 constituting the second sheet included in the laminated block body, there are formed a first sealing portion 131 that fills a third through hole H3 straddling the first end portion E21 of each element region, and a second sealing portion 132 that fills a fourth through hole H4 straddling the second end portion E22 of each element region.

[0128] Therefore, when the metal foil 21 is cut by dicing or the like so that the first sealing portion 131 and the second sealing portion 132 are separated on both sides at the positions of the first end portion E21 and the second end portion E22 of each element region, as shown in FIG. 16B, on the first end face E101 which is the cut surface on the first end portion E21 side, the metal foil 21 and the first sealing portion 131 are exposed. On the other hand, on the second end face E102 which is the cut surface on the second end portion E22 side, the second sealing portion 132 is exposed and the metal foil 21 is not exposed.

[0129] Also, when the metal foil 21 is cut at the positions of the first side portion S21 and the second side portion S22 of each element region, as shown in FIG. 16B, the metal foil 21 is exposed on both cut surfaces.

[0130] As described above, by cutting the laminated block body at the positions of the first end portion and the second end portion of each element region, the metal foil and the first sealing portion can be exposed on the first end surface of the obtained element laminate, and the valve-acting metal substrate and the second sealing portion can be exposed on the second end surface.

[0131] Further, on the cut surface obtained by cutting the laminated block body at the positions of the first side portion and the second side portion of each element region, both the metal foil and the valve-acting metal substrate are exposed. Therefore, it is preferable to form a fourth sealing portion that covers each side surface of the element laminate.

[0132] FIG. 17 is a cross-sectional view schematically showing an example of the element laminate. FIG. 18A is a perspective view of the element laminate shown in FIG. 17 as viewed from the first end surface side. FIG. 18B is a perspective view of the element laminate shown in FIG. 17 as viewed from the second end surface side. Note that FIG. 17 is a cross-sectional view taken along line A-A of the element laminate shown in FIG. 18A.

[0133] In the element laminate 100 shown in FIGS. 17, 18A, and 18B, as shown in FIG. 17, a first layer 110 including a valve-acting metal substrate 11 having a porous portion (not shown) on the surface, a dielectric layer 12 formed on the surface of the porous portion, and a solid electrolyte layer 13 provided on the dielectric layer 12, and a second layer 120 made of a metal foil 21 are laminated. The first layer 110 and the second layer 120 are laminated alternately along the lamination direction (T direction). However, considering weather resistance such as moisture resistance and heat resistance, as shown in FIG. 17, it is preferable that the second layer 120, which is a metal foil, is located in the outermost layers (excluding the third sealing portion 133) facing each other in the lamination direction. In addition, in FIGS. 17, 18A, and 18B, the mask layer 14, the adhesive resin 15, and the conductor layer 16 are omitted.

[0134] As shown in FIGS. 17 and 18A, the metal foil 21 and the first sealing portion 131 are exposed on the first end surface E101 of the element laminate 100. On the other hand, as shown in FIGS. 17 and 18B, the valve-acting metal substrate 11 and the second sealing portion 132 are exposed on the second end surface E102 of the element laminate 100.

[0135] Further, the element laminate 100 further includes a third sealing portion 133 that covers each main surface and a fourth sealing portion 134 that covers each side surface.

[0136] The element laminate is preferably manufactured as follows.

[0137] First, the laminated block body is cut along the first side portion and the second side portion of each element region. For cutting the laminated block body, for example, a method such as dicing using a dicing saw is applied.

[0138] FIG. 19A is a perspective view schematically showing an example of the laminated block body after being cut. FIG. 19B is an enlarged perspective view of a part of the laminated block body shown in FIG. 19A, with the parts disassembled. For example, by cutting the laminated block body 40 shown in FIG. 14A along the first side portion and the second side portion of each element region, a laminated block body 40a having a gap G formed along the first side portion and the second side portion is produced as shown in FIGS. 19A and 19B. In the laminated block body 40a, as shown in FIG. 19B, the metal foil 21 and the valve-acting metal substrate 11 are exposed on the cut side surface exposed by the cutting. Although not shown, the thickness (thickness in the T direction) of the exposed portions of the metal foil 21 and the valve-acting metal substrate 11 is larger than the thickness of the internal metal foil 21 and the valve-acting metal substrate 11 that are not exposed, and tapers and spreads in the vertical direction of the thickness direction.

[0139] Next, the gap formed in the laminated block body is filled with a sealing material. Thereby, a fourth sealing portion that fills the above gap is formed. As the sealing material, for example, the sealing material for forming the first sealing portion and the second sealing portion can be used.

[0140] FIG. 20A is a perspective view schematically showing an example of the laminated block body in which the fourth sealing portion is formed. FIG. 20B is an enlarged perspective view of a part of the laminated block body shown in FIG. 20A, with the parts disassembled. By filling the gap G of the laminated block body 40a shown in FIG. 19A with a sealing material, as shown in FIGS. 20A and 20B, a laminated block body 40b is produced in which a fourth sealing portion 134 for filling the gap G is formed.

[0141] Thereafter, the laminated block body is cut at the positions of the first end portion and the second end portion of each element region so as to separate the first sealing portion 131 and the second sealing portion 132 on both sides, and at the positions of the first side portion and the second side portion of each element region, the fourth sealing portion 134 is cut so as to be separated on both sides. Thereby, it is possible to individualize the element laminate in which the first side portion and the second side portion are insulated by the sealing portion. For cutting the laminated block body, for example, dicing using a dicing saw, a cutting blade, a laser process, a scribing method, etc. are applied. When the first sheet and the second sheet are laminated on a substrate made of a glass epoxy resin or the like, in order to surely cut the second sheet which is a metal foil, it is preferable to cut the substrate to the position for half-cutting. By half-cutting, a stepped shape is generated from the first side portion and the second side portion of each element region to the substrate, and this stepped shape is in a state of being filled by a part of the fourth sealing portion 134.

[0142] FIG. 21A is a perspective view schematically showing an example of the individualized element laminate. FIG. 21B is an exploded and enlarged perspective view of a part of the element laminate shown in FIG. 21A. By cutting the laminated block body 40b shown in FIG. 20A at the positions of the first end portion and the second end portion of each element region and at the positions of the first side portion and the second side portion of each element region, the element laminate 100 shown in FIG. 21A is obtained. At this time, as shown in FIGS. 21A and 21B, the laminated block body 40b is cut so that the cut side surfaces appearing by cutting at the positions of the first side portion and the second side portion are constituted by the fourth sealing portion 134.

[0143] (H) Step of forming the first external electrode and the second external electrode For the obtained element laminate, a first external electrode is formed on the first end face, and a second external electrode is formed on the second end face. Thus, a solid electrolytic capacitor is obtained.

[0144] The solid electrolytic capacitor 1 shown in FIG. 1 includes an element laminate 100 shown in FIG. 17, a first external electrode 141 provided on the first end face E101 of the element laminate 100, and a second external electrode 142 provided on the second end face E102 of the element laminate 100. The first external electrode 141 is connected to the metal foil 21 exposed on the first end face E101, and the second external electrode 142 is connected to the valve-acting metal substrate 11 exposed on the second end face E102.

[0145] The first external electrode and the second external electrode can be formed, for example, by plating, sputtering, dip coating, printing, or the like. In the case of plating, as the plating layer, a Zn·Ag·Ni layer, an Ag·Ni layer, a Ni layer, a Zn·Ni·Au layer, a Ni·Au layer, a Zn·Ni·Cu layer, a Ni·Cu layer, or the like can be used. It is preferable to further form a plating layer, for example, in the order of a Cu plating layer, a Ni plating layer, and a Sn plating layer (or excluding a part thereof) on these plating layers.

[0146] (Second Embodiment) [Solid Electrolytic Capacitor] The solid electrolytic capacitor according to the second embodiment of the present invention is substantially the same as the solid electrolytic capacitor according to the first embodiment of the present invention, except that no conductor layer is provided between the solid electrolyte layer and the metal foil. That is, the solid electrolytic capacitor according to the present embodiment has the same structure as the solid electrolytic capacitor 1 shown in FIGS. 1 to 8. However, for cost reduction and process simplification, the valve-acting metal substrate 11 and the metal foil 21 are connected without passing through other conductor layers of the solid electrolyte layer 13. In this case, they may be connected via a conductive adhesive layer (for example, a solid electrolyte layer containing a binder) provided on the solid electrolyte layer 13.

[0147] [Method for Manufacturing Solid Electrolytic Capacitor] Hereinafter, an example of the manufacturing method of the solid electrolytic capacitor according to the present embodiment will be described step by step.

[0148] (A) Step of preparing the first sheet First, as shown in FIGS. 9A and 9B, the first sheet is prepared in the same manner as in the first embodiment. However, the solid electrolyte layer 13 is preferably formed thicker than in the first embodiment.

[0149] (B) Step of preparing the second sheet Separately, as shown in FIGS. 10A and 10B, the second sheet is prepared in the same manner as in the first embodiment.

[0150] (E) Step of producing the laminated sheet In the same manner as in the first embodiment, the first sheet and the second sheet are laminated so that the first ends and the second ends of each element region face each other, thereby producing a laminated sheet. In the obtained laminated sheet, the first through-hole and the third through-hole, and the second through-hole and the fourth through-hole are respectively communicated in the lamination direction.

[0151] The second through-hole and the third through-hole are preferably linearly communicated from the first main surface to the second main surface of the laminated sheet.

[0152] When laminating the first sheet and the second sheet, the valve action metal substrate and the metal foil are connected without passing through other conductor layers of the solid electrolyte layer. In this case, the valve action metal substrate and the metal foil may be connected through a conductive adhesive layer provided on the solid electrolyte layer (for example, a solid electrolyte layer containing a binder).

[0153] Also, for the portions where the solid electrolyte layer or the conductive adhesive layer is not provided, the valve action metal substrate and the metal foil are connected through an adhesive resin.

[0154] FIG. 22A is a perspective view schematically showing an example of the first sheet provided with the adhesive resin. FIG. 22B is an enlarged perspective view of a part of the first sheet shown in FIG. 22A. In FIGS. 22A and 22B, similar to the first embodiment, an adhesive resin (adhesive layer) 15 before solidification or curing is provided on the mask layer 14 of the first sheet 10 shown in FIGS. 9A and 9B.

[0155] When laminating the first sheet and the second sheet, it is preferable to place the metal foil on the layer located under the metal foil in a viscous state. Since the solid electrolyte layer before drying is in a viscous state, it is suitable for directly placing the metal foil. In this case, it is preferable to form the solid electrolyte layer thicker than in the first embodiment. On the other hand, when the solid electrolyte layer as the layer located under the metal foil is dried, it becomes difficult to adhere the metal foil, so it is preferable to place the metal foil after providing a conductive adhesive layer (for example, a solid electrolyte layer containing a binder).

[0156] FIG. 23A is a perspective view schematically showing an example of the state before laminating the first sheet and the second sheet. FIG. 23B is a perspective view schematically showing an example of the laminated sheet. As shown in FIG. 23A, similar to the first embodiment, the first sheet 10 and the second sheet 20 are alternately laminated, and the adhesive resin 15 is solidified or cured to obtain the laminated sheet 30 shown in FIG. 23B. However, in this embodiment, the solid electrolyte layer of the first sheet 10 and the metal foil of the second sheet 20 are directly connected or connected via a conductive adhesive layer provided on the solid electrolyte layer.

[0157] (F) Step of manufacturing a laminated block body Similar to the first embodiment, a laminated block body is manufactured by filling a sealing material into the first through hole and the third through hole, and the second through hole and the fourth through hole, respectively, from at least one main surface side of the obtained laminated sheet.

[0158] FIG. 24A is a perspective view schematically showing an example of the laminated block body. FIG. 24B is an enlarged perspective view of a part of the laminated block body shown in FIG. 24A, with the components disassembled. Similar to the first embodiment, in the laminated block body 40 shown in Fig. 24A, by filling the first through hole and the third through hole, and the second through hole and the fourth through hole with a sealing material respectively, as shown in Fig. 24B, a first sealing portion 131 that fills the first through hole H1 and the third through hole H3, and a second sealing portion 132 that fills the second through hole H2 and the fourth through hole H4 are formed. However, different from the first embodiment, a conductor layer is not provided on the first sheet 10. Further, as shown in Fig. 24A, the laminated block body 40 further includes a third sealing portion 133 that covers each main surface.

[0159] (G) A step of manufacturing a plurality of element laminate bodies by cutting the laminated block body Subsequently, similar to the first embodiment, the laminated block body is cut at the positions of the first end portion and the second end portion of each element region, and at the positions of the first side portion and the second side portion of each element region, thereby manufacturing a plurality of element laminate bodies.

[0160] (H) A step of forming a first external electrode and a second external electrode For the obtained element laminate body, similar to the first embodiment, a first external electrode is formed on the first end surface, and a second external electrode is formed on the second end surface. Thus, a solid electrolytic capacitor according to the second embodiment is obtained.

[0161] The following content is disclosed in this specification.

[0162] <1> A solid electrolytic capacitor including an element laminate body, a first external electrode, and a second external electrode, in the element laminate body, a first layer and a second layer are laminated via an adhesive resin, the first layer includes a valve action metal substrate having a dielectric layer formed on a surface thereof, and a solid electrolyte layer provided on the dielectric layer, the second layer is made of a metal foil, Furthermore, in the element laminate, among the first end face and the second end face facing each other in the length direction, the metal foil and the first sealing portion are exposed on the first end face, and the valve-acting metal substrate and the second sealing portion are exposed on the second end face. The first external electrode is provided on the first end face of the element laminate and is connected to the metal foil. The second external electrode is provided on the second end face of the element laminate and is connected to the valve-acting metal substrate. The first sealing portion has a first columnar portion penetrating the metal foil in the stacking direction and a first strip portion provided between the metal foils and connecting between the first columnar portions. The second sealing portion has a second columnar portion penetrating the valve-acting metal substrate in the stacking direction and a second strip portion provided between the valve-acting metal substrates and connecting between the second columnar portions. The adhesive resin has fewer fillers than the first sealing portion and the second sealing portion, and in the element laminate, at least one of a first region between the metal foil and the first columnar portion, a second region between the valve-acting metal substrate and the first strip portion, a third region between the valve-acting metal substrate and the second columnar portion, and a fourth region between the metal foil and the second strip portion. The solid electrolytic capacitor exists.

[0163] <2> The adhesive resin exists in at least one of the first region and the third region inside the element laminate. The solid electrolytic capacitor according to <1>.

[0164] <3> The adhesive resin exists in the first region and the third region inside the element laminate. The solid electrolytic capacitor according to <2>.

[0165] <4> The adhesive resin covers at least one of the entire end face of the metal foil facing the first columnar portion and the entire end face of the valve-acting metal substrate facing the second columnar portion. The solid electrolytic capacitor according to <2> or <3>.

[0166] <5> The adhesive resin is exposed from the inside of the element laminate to at least one of the first end face and the second end face, and is the solid electrolytic capacitor according to any one of <1> to <4>.

[0167] <6> The adhesive resin is exposed from the inside of the element laminate to the first end face and the second end face, and is the solid electrolytic capacitor according to <5>.

[0168] <7> The adhesive resin does not contain a filler, and is the solid electrolytic capacitor according to any one of <1> to <6>.

[0169] <8> The Poisson's ratio of the adhesive resin is 0.3 or more, and is the solid electrolytic capacitor according to any one of <1> to <7>.

Explanation of reference numerals

[0170] 1 Solid electrolytic capacitor 10 First sheet 11 Valve-acting metal substrate 11a Notch of the valve-acting metal substrate 11b End face of the valve-acting metal substrate 12 Dielectric layer 13 Solid electrolyte layer 14 Mask layer 15 Adhesive resin 16 Conductor layer 20 Second sheet 21 Metal foil 21a Notch of the metal foil 21b End face of the metal foil 30 Laminated sheet 40, 40a, 40b Laminated block body 100 Element laminate 110 First layer 120 Second layer 131 First sealing portion 131a First columnar portion 131b First strip portion 132 Second sealing portion 132a Second columnar portion 132b Second strip portion 133 Third sealing portion 134 Fourth sealing portion 141 First external electrode 142 Second external electrode A1 Sum of distances per layer where the metal foil is exposed on the first end face A11, A12, A13, A14 Distance per layer where the metal foil is exposed on the first end face A2 Sum of distances per layer where the valve - acting metal substrate is exposed on the second end face A21, A22, A23, A24 Distance per layer where the valve - acting metal substrate is exposed on the second end face B1 Maximum width of the metal foil B2 Maximum width of the valve - acting metal substrate R11 First element region of the first sheet R12 Second element region of the first sheet R21 First element region of the second sheet R22 Second element region of the second sheet E11 First end of the element region of the first sheet E12 Second end of the element region of the first sheet E21 First end of the element region of the second sheet E22 Second end of the element region of the second sheet E101 First end face of the element laminate E102 Second end face of the element laminate S11 First side of the element region of the first sheet S12 Second side of the element region of the first sheet S21 First side of the element region of the second sheet S22 Second side of the element region of the second sheet S101 First side face of the element laminate S102 Second side face of the element laminate M31 First main face of the laminated sheet M32 Second main face of the laminated sheet The first main surface of the M101 element laminate The second main surface of the M102 element laminate H1 The first through-hole H2 The second through-hole H3 The third through-hole H4 The fourth through-hole G The gap of the laminated block body

Claims

1. A solid electrolytic capacitor including an element laminate, a first external electrode, and a second external electrode, in the element laminate, a first layer and a second layer are laminated via an adhesive resin, the first layer includes a valve action metal substrate having a dielectric layer formed on a surface thereof, and a solid electrolyte layer provided on the dielectric layer, the second layer is made of a metal foil, further, in the element laminate, of a first end face and a second end face facing each other in a length direction, the metal foil and a first sealing portion are exposed on the first end face, and the valve action metal substrate and a second sealing portion are exposed on the second end face, the first external electrode is provided on the first end face of the element laminate and is connected to the metal foil, the second external electrode is provided on the second end face of the element laminate and is connected to the valve action metal substrate, the first sealing portion has a first columnar portion penetrating the metal foil in a lamination direction, and a first strip portion provided between the metal foils and connecting between the first columnar portions, the second sealing portion has a second columnar portion penetrating the valve action metal substrate in the lamination direction, and a second strip portion provided between the valve action metal substrates and connecting between the second columnar portions, the adhesive resin has fewer fillers than the first sealing portion and the second sealing portion, and in the element laminate, at least one of a first region between the metal foil and the first columnar portion, a second region between the valve action metal substrate and the first strip portion, a third region between the valve action metal substrate and the second columnar portion, and a fourth region between the metal foil and the second strip portion, and also exists in at least one of the first region and the third region. A solid electrolytic capacitor.

2. The solid electrolytic capacitor according to claim 1, wherein the adhesive resin exists in the first region and the third region inside the element laminate.

3. The solid electrolytic capacitor according to claim 1 or 2, wherein the adhesive resin covers at least one of the entire end face of the metal foil facing the first columnar portion and the entire end face of the valve-acting metal substrate facing the second columnar portion.

4. The solid electrolytic capacitor according to claim 1 or 2, wherein the adhesive resin is exposed to at least one of the first end face and the second end face from inside the element laminate.

5. The solid electrolytic capacitor according to claim 4, wherein the adhesive resin is exposed to the first end face and the second end face from inside the element laminate.

6. The solid electrolytic capacitor according to claim 1 or 2, wherein the adhesive resin does not contain a filler.

7. The solid electrolytic capacitor according to claim 1 or 2, wherein the Poisson's ratio of the adhesive resin is 0.3 or more.

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