Solid electrolytic capacitor

Abstract

To prevent displacement of a valve metal substrate constituting a capacitor element in the width direction.SOLUTION: A solid electrolytic capacitor 1 includes a capacitor element 10 having a valve metal substrate 11, one end of which in the longitudinal direction L, a first end 11a, which is an anode terminal region, and the other end, a second end 11b, which is a cathode formation region, a sealing material 20 that seals the capacitor element 10 to form a sealing body 30, an anode external electrode 40 that is provided on at least the bottom surface 34 of the sealing body 30 and electrically connected to the anode terminal region, and a cathode external electrode 50 that is provided on the surface of the sealing body 30 and electrically connected to the cathode formation region, and a conductive spacer 60 is disposed between the bottom surface 11c of the anode terminal region of the valve metal substrate 11 and the anode external electrode 40, and two or more protrusions 61 protruding from the conductive spacer 60 are provided at positions sandwiching the anode terminal region of the valve metal substrate 11 in the width direction W.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a solid electrolytic capacitor including a plurality of capacitor elements. Specifically, the anode portions of the plurality of capacitor elements are grouped together and connected by welding or the like to an anode step portion connected to an anode terminal (see, for example, Figure 2 of Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6928790 Summary of the Invention [Problem to be solved by the invention]

[0004] By providing an anode step connected to the anode terminal, the difference in thickness between the anode and cathode portions is eliminated, allowing the laminate of the capacitor element to be positioned straight. If the laminate cannot be positioned straight, it may be difficult to reduce the height of the chip.

[0005] In the solid electrolytic capacitor having the above-described configuration, when the laminate is mounted on the anode step, the laminate may be misaligned outward in the width direction of the solid electrolytic capacitor. When the laminate is misaligned in the width direction, the sealing material sealing the laminate may become locally thin, potentially resulting in portions of the laminate being exposed from the sealing material.

[0006] The present invention has been made to solve the above problems, and has as its object to provide a solid electrolytic capacitor in which displacement in the width direction of the valve metal substrate that constitutes the capacitor element is prevented. [Means for solving the problem]

[0007] The solid electrolytic capacitor of the present invention comprises a capacitor element having a valve action metal base having an anode terminal region at one longitudinal end, that is a first end, and a cathode formation region at the other longitudinal end, that is a second end; a sealing material that seals the capacitor element to form a sealed body; an anode external electrode that is provided on at least the bottom surface of the sealed body and is electrically connected to the anode terminal region; and a cathode external electrode that is provided on the surface of the sealed body and is electrically connected to the cathode formation region, wherein a conductive spacer is disposed between the bottom surface of the anode terminal region of the valve action metal base and the anode external electrode, and two or more protrusions protruding from the conductive spacer are provided at positions that sandwich the anode terminal region of the valve action metal base in the width direction. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a solid electrolytic capacitor in which displacement in the width direction of the valve metal substrate constituting the capacitor element is prevented. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view schematically illustrating an example of a solid electrolytic capacitor. [Figure 2] FIG. 2 is a cross-sectional view of the solid electrolytic capacitor shown in FIG. 1 taken along line AA. [Figure 3] FIG. 3 is an enlarged perspective view schematically illustrating the vicinity of the upper surface of the conductive spacer shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view of the solid electrolytic capacitor shown in FIG. 2 taken along line BB. [Figure 5] FIG. 5 is a cross-sectional view schematically showing another example of the shape of the convex portion. [Figure 6] FIG. 6 is a cross-sectional view schematically showing an example of a configuration in which a low-melting-point conductive member is not provided on the surface of a protrusion, at the same position as the cross-sectional view of the solid electrolytic capacitor taken along line BB shown in FIG. [Figure 7]FIG. 7 is a perspective view schematically showing an example of a configuration in which a low-melting-point conductive member is provided between the bottom surface of the anode terminal region of the valve metal substrate and the upper surface of the conductive spacer at the same position as near the upper surface of the conductive spacer shown in FIG. [Figure 8] FIG. 8 is a perspective view schematically showing another example of a solid electrolytic capacitor. [Figure 9] FIG. 9 is a cross-sectional view of the solid electrolytic capacitor shown in FIG. 8 taken along line CC. [Figure 10] FIG. 10 is a cross-sectional view of the solid electrolytic capacitor shown in FIG. 9 taken along line DD. [Figure 11] FIG. 11 is a cross-sectional view schematically showing an example of a configuration in which a low-melting-point conductive member is not provided on the surface of the convex portion and a low-melting-point conductive member is not provided between the bottom surface of the anode terminal region of the valve metal base and the upper surface of the conductive spacer, at the same position as the DD-line cross-sectional view of the solid electrolytic capacitor shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] The solid electrolytic capacitor of the present invention will now be described. However, the present invention is not limited to the following configurations, and can be appropriately modified and applied within the scope of the present invention. Note that the present invention also includes a combination of two or more of the preferred configurations of each embodiment of the present invention described below.

[0011] [Solid electrolytic capacitor] The solid electrolytic capacitor of the present invention comprises a capacitor element having a valve action metal base having an anode terminal region at one longitudinal end, that is a first end, and a cathode formation region at the other longitudinal end, that is a second end; a sealing material that seals the capacitor element to form a sealed body; an anode external electrode that is provided on at least the bottom surface of the sealed body and is electrically connected to the anode terminal region; and a cathode external electrode that is provided on the surface of the sealed body and is electrically connected to the cathode formation region, wherein a conductive spacer is disposed between the bottom surface of the anode terminal region of the valve action metal base and the anode external electrode, and two or more protrusions protruding from the conductive spacer are provided at positions that sandwich the anode terminal region of the valve action metal base in the width direction.

[0012] FIG. 1 is a perspective view schematically showing an example of a solid electrolytic capacitor, and FIG. 2 is a cross-sectional view of the solid electrolytic capacitor shown in FIG. 1 taken along line AA. In the solid electrolytic capacitor 1 shown in FIGS. 1 and 2, a plurality of capacitor elements 10 are sealed with a sealing material 20 to form a sealing body 30. The sealing material 20 may be made of, for example, epoxy resin. 1 and 2 show the longitudinal direction (L direction), width direction (W direction), and thickness direction (T direction) of the solid electrolytic capacitor.

[0013] The sealing body 30 has an approximately rectangular parallelepiped shape and has a first end face 31, a second end face 32 opposite the first end face 31 in the lengthwise direction, a top face 33, a bottom face 34 opposite the top face 33 in the thickness direction, a first side face 35, and a second side face 36 opposite the first side face 35 in the widthwise direction. Bottom surface 34 is the surface that serves as the mounting surface when mounting solid electrolytic capacitor 1. Bottom surface 34 and top surface 33 face each other in the stacking direction (thickness direction, T direction) in which multiple capacitor elements 10 are stacked.

[0014] An anode external electrode 40 is provided on at least the bottom surface 34 of the sealing body 30. In the solid electrolytic capacitor 1 shown in FIG.

[0015] A cathode external electrode 50 is provided on the surface of the sealing body 30. In the solid electrolytic capacitor 1 shown in Fig. 1, the cathode external electrode 50 is provided across the bottom surface 34 and the second end surface 32 of the sealing body. The cathode external electrode may be provided on any one of the surfaces of the sealing body, and it is not essential that it be provided on the bottom surface, but it is preferably provided on the bottom surface, which is the mounting surface.

[0016] The capacitor element 10 comprises a valve metal substrate 11 having a first end 11a, which is one longitudinal end, that is an anode terminal region (region indicated by a double-headed arrow a in FIG. 2), and a second end 11b, which is the other longitudinal end, that is a cathode formation region (region indicated by a double-headed arrow b in FIG. 2). The capacitor element 10 further comprises a dielectric layer 12 formed on the anode terminal region and the cathode formation region, a solid electrolyte layer 13 formed on the dielectric layer 12, and a conductive layer 14 formed on the solid electrolyte layer 13. A masking region made of a masking member 15 is formed on the anode terminal region a to separate the anode terminal region a from the cathode formation region b and to insulate the valve metal substrate 11 from the counter electrode. The capacitor element does not necessarily have to have a masking region.

[0017] The valve metal substrate is made of a valve metal that exhibits so-called valve action. Examples of the valve metal include simple metals such as aluminum, tantalum, niobium, titanium, and zirconium, as well as alloys containing these metals. Among these, aluminum or an aluminum alloy is preferred.

[0018] The valve metal substrate is preferably in the form of a flat plate, more preferably in the form of a foil. A porous layer such as an etching layer is preferably provided on the surface of the valve metal substrate. The porous layer on the valve metal substrate increases the surface area of ​​the valve metal substrate, which serves as the anode, thereby increasing the capacitance of the capacitor.

[0019] The dielectric layer is preferably formed on the cathode-forming region of the valve metal substrate and is made of an oxide film of the valve metal. For example, when an aluminum foil is used as the valve metal substrate, the oxide film can be formed by oxidizing the aluminum foil in an aqueous solution containing boric acid, phosphoric acid, adipic acid, or their sodium salts or ammonium salts. The dielectric layer may or may not be formed on the anode terminal region of the valve metal substrate.

[0020] The solid electrolyte layer is formed on the dielectric layer on the cathode forming region. When the valve metal substrate has a porous layer, the solid electrolyte layer is preferably composed of an inner layer impregnated in the porous layer of the valve metal and an outer layer covering the inner layer. The inner and outer layers may have the same composition or different compositions.

[0021] Examples of materials constituting the solid electrolyte layer include conductive polymers with a skeleton of pyrroles, thiophenes, anilines, etc. Examples of conductive polymers with a skeleton of thiophenes include PEDOT [poly(3,4-ethylenedioxythiophene)], which may be PEDOT:PSS, which is a composite of PEDOT and polystyrene sulfonic acid (PSS) as a dopant.

[0022] The conductive layer is formed on the solid electrolyte layer. The conductive layer is preferably a carbon layer, a graphene layer, or a silver layer formed by applying a conductive paste such as carbon paste, graphene paste, or silver paste. The conductive layer may also be a composite layer in which a silver layer is provided on a carbon layer or a graphene layer, or a mixed layer in which a carbon paste or a graphene paste is mixed with a silver paste. Specifically, it is preferable that the silver layer be formed on a carbon layer as a base, but it may be formed of only a carbon layer or only a silver layer.

[0023] Examples of materials for the masking member include insulating resins such as polyphenylsulfone resin, polyethersulfone resin, cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, etc.), polyimide resin, polyamideimide resin, and derivatives or precursors thereof.

[0024] 1 and 2, multiple (five) capacitor elements 10 are stacked. The number of stacked capacitor elements is not limited and may be one or more. For example, it is preferable that the number be one or more and six or less. On the anode terminal area side, the valve metal substrates 11 of the capacitor elements 10 are grouped together and extended to the anode external electrode 40 on the bottom surface 34 of the sealing body via the conductive spacer 60 .

[0025] A conductive spacer 60 is disposed between the bottom surface 11 c of the valve metal substrate 11 made up of a plurality of plates and the external anode electrode 40 . The valve metal substrate 11 is connected to the conductive spacer 60, and since the conductive spacer 60 is made of a conductive material, the anode terminal region of the valve metal substrate 11 is electrically connected to the anode external electrode 40. The material of the conductive spacer 60 is not limited as long as it has conductivity sufficient to electrically connect the valve metal substrate and the external anode electrode. Furthermore, a material with high thermal conductivity is preferred. From these viewpoints, metals are preferred, such as copper, aluminum, and nickel.

[0026] The conductive spacer 60 is preferably joined to the valve metal substrate 11 and the anode external electrode 40 by resistance welding or laser welding.

[0027] The conductive spacer 60 is a rectangular parallelepiped block, and by placing the valve metal substrate 11 on the conductive spacer 60, the amount of bending of the valve metal substrate 11 is reduced, and the load applied to the valve metal substrate 11 is reduced.

[0028] On the cathode forming region side, the conductive layers 14 of the capacitor elements 10 are electrically connected, and further electrically connected to the cathode external electrode 50 , and are drawn out of the sealing body 30 .

[0029] In the solid electrolytic capacitor of the present invention, two or more protrusions protruding from the conductive spacer are provided at positions sandwiching the anode terminal region of the valve metal substrate in the width direction.

[0030] FIG. 3 is an enlarged perspective view schematically illustrating the vicinity of the upper surface of the conductive spacer shown in FIG. FIG. 4 is a cross-sectional view of the solid electrolytic capacitor shown in FIG. 2 taken along line BB. FIG. 4 shows a cross section (WT cross section) of the solid electrolytic capacitor 1 at a position slightly inward from the anode external electrode 40 toward the sealing body.

[0031] Figure 3 shows three protrusions 61, which are columnar portions protruding from the upper surface of the conductive spacer 60, with two protrusions on one side of the width direction of the anode terminal region of the valve metal substrate 11 (at the rear right of the drawing) and one protrusion on the other side (at the front left of the drawing).

[0032] Figure 4 shows two protrusions 61, which are pillars protruding from the upper surface of the conductive spacer 60, and illustrates that the anode terminal region of the valve metal substrate 11 is sandwiched between the two protrusions 61 in the width direction. The protrusions 61 may be formed by hammering into the conductive spacer 60, or may be integrated with the conductive spacer 60. When the conductive spacer is made of copper, the convex portion is preferably made of copper as well.

[0033] If two or more protrusions protruding from the conductive spacer are provided at positions that sandwich the anode terminal region of the valve action metal base in the width direction, it is possible to prevent the valve action metal base constituting the capacitor element from being misaligned in the width direction.

[0034] The number of protrusions may be two or more, preferably three or more, because three or more protrusions make it easier to prevent misalignment of the valve metal base when it tries to rotate.

[0035] Furthermore, when the valve action metal substrate is made of aluminum foil and is welded to a conductive spacer, welding sag (splash welding sag) may occur, in which molten aluminum splashes out during welding.Also, liquefied aluminum may accumulate on the surface of the conductive spacer and spill over and drop from the surface of the conductive spacer, causing welding sag. If a protrusion protruding from the conductive spacer is provided, the protrusion can prevent the aluminum from popping out. Also, a certain amount of molten aluminum can be accumulated in the space between the protrusion and the valve metal base. Due to these effects, providing the protrusion can also prevent welding sagging.

[0036] It is also preferable that a low melting point conductive material is provided on the surface of the protrusion. In FIG. 4, the low melting point conductive material 62 provided on the surface of the protrusion 61 is shown by hatching the protrusion 61 and the low melting point conductive material 62 differently. The low melting point conductive member 62 is preferably made of a low melting point metal that is easy to weld, and examples thereof include Sn, In, Bi, Zn, Sb, Al, and solder containing these metals. When the low-melting point conductive member is provided, the valve metal base and the protrusion can be joined by welding, which more reliably prevents the valve metal base from being displaced in the width direction and also in the length direction.

[0037] Furthermore, if a low-melting point conductive material is provided on the surface of the convex portion, when the valve action metal base is resistance welded to the conductive spacer, the low-melting point conductive material melts and pulls the valve action metal base together, thereby exhibiting a self-alignment function and improving the mounting accuracy of the valve action metal base. The entire protrusion serving as the column may be made of a low-melting point conductive material.

[0038] Although FIG. 3 shows an example in which the shape of the convex portion is cylindrical, the shape of the convex portion is not limited to cylindrical, and examples thereof include a columnar shape (cylindrical, prismatic), a hemispherical shape, a spherical shape, a conical shape (circular cone, pyramidal shape), a tapered shape (angular tapered shape, arc tapered shape), etc. FIG. 5 is a cross-sectional view schematically showing another example of the shape of the convex portion. Figure 5 shows examples of the shape of the convex portion, from left to right in the upper row, including a columnar (cylindrical) shape 63a, a hemispherical shape 63b, and a spherical shape 63c, and examples of the shape of the convex portion, from left to right in the lower row, including a cone shape (triangular pyramid) 63d, a square tapered shape 63e, and an arc tapered shape 63f.

[0039] 5 (angular tapered shape 63e, arc tapered shape 63f), the valve metal base is placed on the right side of the protrusion. If the valve metal base is placed on the left side of the protrusion, the taper direction will be reversed. The taper refers to the inclined side surface of the convex portion, and the valve metal substrate is disposed on the side of the tapered side surface.

[0040] From the viewpoint of preventing displacement of the valve metal substrate in the width direction, the shape of the convex portion is preferably hemispherical, spherical, pyramidal (conical, pyramidal) or tapered (angular tapered, arc tapered). In the case of a hemispherical or spherical shape, the position of the valve metal substrate is adjusted based on the protruding portion of the hemispherical or spherical shape, and in the case of a conical or tapered shape, the position of the valve metal substrate is adjusted along the inclined side surface of the convex portion.

[0041] From the viewpoint of preventing welding sagging, it is preferable that the shape of the convex portion is a pyramidal shape (conical or pyramidal) or a tapered shape (angular tapered shape or arc tapered shape). In the case of a cone-like or tapered shape, a large space is formed between the protrusion and the valve metal base, allowing a large amount of molten aluminum to be accumulated in this space, thereby making it possible to more effectively prevent welding sagging.

[0042] Table 1 shows the relationship between the height h of the protrusion, the total thickness H of the valve metal substrates gathered in the anode terminal region, and the relationship between the functions and effects. The height h of the protrusion and the total thickness H of the valve metal substrate gathered in the anode terminal area are both the dimensions of the parts indicated by the double-headed arrows h and H in Figure 4. Figure 4 shows an example where h = H. The effects associated with the relationship between the height h and the thickness H include an effect of improving the bonding strength between the protrusion and the valve metal substrate, an effect of reducing ESR, and an effect of preventing splash welding sagging. When a low-melting-point conductive member is provided on the surface of a protrusion, the height h of the protrusion is measured as a height including the thickness of the low-melting-point conductive member.

[0043] The effect of improving the joint strength is an effect of improving the joint strength when the protrusion and the valve metal base are joined by resistance welding. The ESR reduction effect is due to the reduction in resistance caused by the increased conductive area due to the bonding between the protrusions and the valve metal substrate. The effect of preventing splash welding sag is achieved by the protrusions preventing the splashing out of aluminum melted by welding when the valve metal substrate is resistance welded to the conductive spacer. The meanings of the evaluation symbols are as follows: ◎: Highly effective ○: Effective △: Somewhat effective ×: No effect

[0044] [Table 1]

[0045] The above effect is achieved if there are protrusions, as shown in Table 1. To effectively achieve the effect of preventing splash welding sag, it is preferable that (1 / 6)H≦h. In order to achieve a high effect in preventing the bonding strength, it is preferable that (1 / 3)H≦h. In order to achieve a high effect in reducing ESR, it is preferable that (2 / 3)H≦h. In order to achieve a high effect in preventing splash welding sag, it is preferable that (5 / 6)H≦h.

[0046] The height h of the convex portion itself is preferably 100 μm or more, more preferably 200 μm or more, and is preferably 900 μm or less, more preferably 600 μm or less. Furthermore, when the height h of the convex portion satisfies the above-mentioned range, it is preferable that the valve metal substrates grouped together in the anode terminal region have a thickness of 120 μm per sheet, there are five stacked sheets, and the total thickness H is 600 μm.

[0047] The size of the convex part is 0.03 mm as the area of ​​its base. 2 Preferably it is 0.06 mm or more 2 It is more preferable that the thickness is 0.13 mm or more. 2 Preferably, it is less than 0.1 mm 2 More preferably, it is:

[0048] A method for manufacturing the solid electrolytic capacitor described above will now be outlined. The conductive spacer can be a block made of a conductive material such as copper. The block can be machined to leave a protrusion, which can then be formed as a protrusion. Alternatively, a columnar material can be driven into the conductive spacer to form a protrusion. Furthermore, the surface of the protrusion can be coated with a low melting point conductive material using a dispenser or the like.

[0049] The anode terminal regions of the valve metal substrates of the capacitor elements are overlapped and placed between the protrusions. The overlapped valve metal substrates can be sucked and moved by a suction nozzle, and after they are aligned between the protrusions, the suction nozzle can be released. A resistance welding terminal is brought into contact with the upper surface of the overlapped anode terminal area, and the overlapped valve metal substrate and conductive spacer are resistance-welded. Laser welding may be used instead of resistance welding. During welding, the aluminum of the valve action metal substrate melts, and the low melting point conductive material provided on the surface of the protrusion melts, welding the overlapping valve action metal substrate and conductive spacer together, and also welding the overlapping valve action metal substrate and protrusion together. The molten aluminum and the molten low-melting point conductive member pull on the remaining protrusion and valve metal substrate, thereby adjusting the position of the valve metal substrate to the center in the width direction of the conductive spacer.

[0050] Although the low melting point conductive material is provided on the surface of the protruding portion of the solid electrolytic capacitor illustrated up to this point, the low melting point conductive material does not have to be provided on the surface of the protruding portion. FIG. 6 is a cross-sectional view schematically showing an example of a configuration in which a low-melting-point conductive member is not provided on the surface of a protrusion, at the same position as the cross-sectional view of the solid electrolytic capacitor taken along line BB shown in FIG. FIG. 6 shows two protrusions 61 protruding from the conductive spacer 60, and illustrates that the anode terminal region of the valve metal substrate 11 is sandwiched between the two protrusions 61 in the width direction. The protrusions 61 shown in FIG. 6 are integrated with the conductive spacers 60, but may be formed by hammering. When the conductive spacer is made of copper, the convex portion is preferably made of copper as well. Although no low melting point conductive material is provided on the surface of the protrusion 61, the effects of the solid electrolytic capacitor of the present invention can be exhibited.

[0051] In the solid electrolytic capacitor of the present invention, a low-melting-point conductive member may be provided between the bottom surface of the anode terminal region of the valve metal base and the upper surface of the conductive spacer, and the anode terminal region of the valve metal base and the conductive spacer may be connected by the low-melting-point conductive member.

[0052] FIG. 7 is a perspective view schematically showing an example of a configuration in which a low-melting-point conductive member is provided between the bottom surface of the anode terminal region of the valve metal substrate and the upper surface of the conductive spacer at the same position as near the upper surface of the conductive spacer shown in FIG.

[0053] In the embodiment shown in FIG. 7, a low-melting point conductive member 64 is provided between the bottom surface 11 c of the valve metal substrate 11 and the upper surface of the conductive spacer 60 . The low-melting-point conductive member provided between the bottom surface of the anode terminal region of the valve metal substrate and the upper surface of the conductive spacer can be made of the same material as the low-melting-point conductive member provided on the surface of the protrusion, preferably Sn plating, for example. The formation of the low-melting-point conductive member provided between the bottom surface of the anode terminal region of the valve metal substrate and the upper surface of the conductive spacer can be carried out simultaneously with the process of providing the low-melting-point conductive member on the surface of the convex portion, and an example method is to simultaneously Sn-plat the upper surface of the conductive spacer and the convex portion.

[0054] By providing a low-melting-point conductive member between the bottom surface of the anode terminal region of the valve metal substrate and the top surface of the conductive spacer, the bonding strength between the valve metal substrate and the conductive spacer by welding can be further improved. In particular, when the surface of the valve metal substrate has a porous structure, there are many irregularities on the surface, so by contacting the low-melting-point conductive member with the surface of the valve metal substrate, the surface area of ​​the bond with the valve metal substrate can be increased. As a result, the bonding strength between the valve metal substrate and the conductive spacer can be increased and the ESR can also be reduced.

[0055] The thickness of the low-melting-point conductive member provided between the bottom surface of the anode terminal region of the valve metal substrate and the upper surface of the conductive spacer is preferably 1 μm or more, more preferably 3 μm or more, and is preferably 100 μm or less, more preferably 10 μm or less.

[0056] In the solid electrolytic capacitors described so far, the convex portion is a column portion protruding from the upper surface of the conductive spacer, but in the solid electrolytic capacitor of the present invention, the convex portion may be a wall portion protruding from the side of the conductive spacer.

[0057] FIG. 8 is a perspective view schematically showing another example of a solid electrolytic capacitor, and FIG. 9 is a cross-sectional view of the solid electrolytic capacitor shown in FIG. 8 taken along line CC. FIG. 10 is a cross-sectional view of the solid electrolytic capacitor shown in FIG. 9 taken along the line DD. The solid electrolytic capacitor 2 shown in FIG. 8 differs from the solid electrolytic capacitor 1 shown in FIG. 1 in the structure of the protrusions. In the solid electrolytic capacitor 2, the sides of the conductive spacer 70 form protruding walls, and protrusions 71 serving as walls are provided at positions that sandwich the anode terminal region of the valve metal substrate 11 in the width direction. The number of protrusions 71 serving as walls is two. Like the protrusions serving as pillars, the protrusions serving as walls can also prevent displacement in the width direction of the valve metal substrate that constitutes the capacitor element.

[0058] The protrusions 71, which are wall portions, protrude obliquely upward and outward from the sides of the conductive spacer 70. The protrusions 71, which are wall portions, are plate-like members that are not integrated with the conductive spacer 70. The materials of the conductive spacers 70 and the protrusions 71 of this embodiment can be the same as the materials of the conductive spacers 60 and the protrusions 61 described above. When the conductive spacer 70 is made of copper, the protrusions 71 are also preferably made of copper.

[0059] If the protrusion is a wall portion, when the valve metal base is welded to the conductive spacer, the wall portion covers the outside of the width direction of the anode terminal region of the valve metal base, so that even if aluminum molten by welding splashes out, it collides with the wall portion, and therefore splash welding sag is more reliably prevented than when the protrusion is a pillar portion. Furthermore, if the protrusions are pillars, it takes time and effort to provide a large number of protrusions, but since only a small number of wall portions are required, the number of steps required during manufacturing can be reduced.

[0060] Furthermore, if the protrusions are wall portions, the path that moisture that has penetrated from the outer peripheral surface of the sealing body must take to reach the valve metal substrate can be lengthened, thereby improving the reliability of the solid electrolytic capacitor.

[0061] When the protrusions are pillars, they are provided on the upper surface of the conductive spacer. When the protrusions are wall portions, they are protruded from the sides of the conductive spacer. In this case, the width of the conductive spacer can be reduced, making the conductive spacer more compact. In addition, heat diffusion during welding of the valve metal substrate and the conductive spacer can be suppressed, allowing welding with low power.

[0062] In the above embodiment, a low-melting-point conductive member 72 is provided on the surface (the surface on the valve metal base side) of the protrusion 71, which is a wall portion. A low-melting-point conductive member 74 is provided between the bottom surface of the valve metal base 11 and the upper surface of the conductive spacer 70. The low melting point conductive member 72 and the low melting point conductive member 74 may be continuous and may be made of the same material, preferably Sn plating, for example.

[0063] Furthermore, it is preferable that the low-melting-point conductive material is not provided on the outer surface of the wall portion of the protrusion (the surface not facing the valve metal base). By not providing the low-melting-point conductive material, the adhesion between the wall portion and the sealing material can be improved.

[0064] If a low-melting point conductive material is provided on the surface of the convex wall portion, when the valve action metal substrate is resistance welded to the conductive spacer, the low-melting point conductive material melts and pulls the valve action metal substrate together, thereby providing a self-alignment function and improving the mounting accuracy of the valve action metal substrate. Furthermore, the bonding strength between the protrusions and the valve metal base increases, and the conductive area increases due to the bonding between the protrusions and the valve metal base, thereby reducing ESR.

[0065] The effect of providing a low melting point conductive member between the bottom surface of the valve metal base and the top surface of the conductive spacer is similar to the effect described in the case where the protrusions are pillars.

[0066] When the protrusions serving as walls are made of a plate-like member, the thickness of the protrusions is preferably 80 μm or more, and more preferably 160 μm or more.

[0067] The low-melting point conductive member provided on the surface of the convex wall portion and between the bottom surface of the anode terminal region of the valve metal base and the upper surface of the conductive spacer can be formed, for example, by simultaneously plating the upper surface of the conductive spacer with Sn.

[0068] As described above, when the convex portion is a wall portion, the dimension of the conductive spacer in the width direction can be reduced, and the width of the conductive spacer can be made smaller than the width of the valve metal substrate. Table 2 shows the relationship between the width W1 of the conductive spacer, the width W2 of the valve metal substrate, and the effects. The relationship between the width W1 of the conductive spacer and the width W2 of the valve metal substrate is the dimensions of the portions indicated by the double arrows W1 and W2 in Figure 10. Figure 10 shows an example where W1 = (3 / 5)W2. The effects associated with the relationship between the width W1 of the conductive spacer and the width W2 of the valve metal base include improving the weldability (joint strength by welding) of the conductive spacer and the valve metal base, preventing splash welding sagging, and preventing molten material from adhering to the welding electrode.

[0069] The effect of improving weldability is the effect of improving the joint strength when the conductive spacer and the valve metal substrate are joined by welding. The effect of preventing splash welding sag is achieved by the protrusions preventing the splashing out of aluminum melted by welding when the valve metal substrate is resistance welded to the conductive spacer. The effect of preventing the adhesion of the melt to the welding electrode is an effect caused by shortening the width W1 of the conductive spacer to avoid excessive generation of the melt. The meanings of the evaluation symbols are as follows. ◎: High effect is exhibited ○: Effect is exhibited △: A little effect is exhibited ×: No effect is exhibited

[0070]

Table 2

[0071] Regarding the relationship between W2 and W1, it was expected that the weldability would be best when the entire width of the valve-acting metal substrate was welded (when W2 = W1). However, in reality, with this dimensional relationship, the entire width of the valve-acting metal substrate is not welded, but is welded at various points in the width direction. In order to exhibit a high effect on weldability, it is preferable that (1 / 5)W2 < W1 ≦ (4 / 5)W2. [[ID=...]] Regarding splash welding drip, it is preferable that the distance between the valve-acting metal substrate and the convex part which is the wall part is not too close nor too far. Therefore, in order to exhibit a high effect on preventing splash welding drip, it is preferable that (2 / 5)W2 < W1 ≦ W2. Since the adhesion of the melt to the welding electrode is more likely to occur as the area of the conductive spacer is larger, it is more preferable that W1 is smaller.

[0072] The width W2 of the valve-acting metal substrate itself is preferably 3 mm or more, and more preferably 4 mm or more.

[0073] Also, the preferable range of the height of the convex part which is the wall part can be made the same as the preferable range of the height of the convex part which is the column part. The height h of the convex part which is the wall part is the height of the part protruding from the upper surface of the conductive spacer (the height indicated by the double arrow h in FIG. 10).

[0074] When the protrusion is a wall portion, the low-melting-point conductive member may not be provided on the surface of the protrusion, and the low-melting-point conductive member may not be provided between the bottom surface of the anode terminal region of the valve metal base and the upper surface of the conductive spacer.

[0075] FIG. 11 is a cross-sectional view schematically showing an example of a configuration in which a low-melting-point conductive member is not provided on the surface of the convex portion and a low-melting-point conductive member is not provided between the bottom surface of the anode terminal region of the valve metal base and the upper surface of the conductive spacer, at the same position as the DD-line cross-sectional view of the solid electrolytic capacitor shown in FIG.

[0076] 11, no low-melting-point conductive member 72 is provided on the surface (the surface on the valve metal base side) of the protrusion 71, which is a wall portion. Also, no low-melting-point conductive member 74 is provided between the bottom surface of the valve metal base 11 and the upper surface of the conductive spacer 70. Furthermore, the protrusions 71, which are wall portions, and the conductive spacers 70 are integrated and made of the same material. Even when the low-melting-point conductive member is not provided, the effect of providing the protrusions as wall portions is exerted.

[0077] The present specification discloses the following:

[0078] The present disclosure (1) provides a solid electrolytic capacitor comprising: a capacitor element having a valve action metal substrate, one longitudinal end of which is a first end that is an anode terminal region, and the other longitudinal end of which is a second end that is a cathode formation region; a sealing material that seals the capacitor element to form a sealed body; an anode external electrode that is provided on at least the bottom surface of the sealed body and is electrically connected to the anode terminal region; and a cathode external electrode that is provided on the surface of the sealed body and is electrically connected to the cathode formation region, wherein a conductive spacer is disposed between the bottom surface of the anode terminal region of the valve action metal substrate and the anode external electrode, and two or more protrusions protruding from the conductive spacer are provided at positions that sandwich the anode terminal region of the valve action metal substrate in the width direction.

[0079] The present disclosure (2) is the solid electrolytic capacitor according to the present disclosure (1), wherein a low-melting point conductive member is provided on the surface of the protrusion at a position where the protrusion is adjacent to the anode terminal region of the valve metal substrate.

[0080] The present disclosure (3) is the solid electrolytic capacitor according to the present disclosure (1) or (2), in which the convex portion is a wall portion protruding from a side portion of the conductive spacer.

[0081] The present disclosure (4) is the solid electrolytic capacitor according to the present disclosure (1) or (2), in which the convex portion is a column portion protruding from the upper surface of the conductive spacer.

[0082] The present disclosure (5) is a solid electrolytic capacitor according to any one of the present disclosures (1) to (4), in which a low-melting point conductive member is provided between the bottom surface of the anode terminal region of the valve metal substrate and the upper surface of the conductive spacer, and the anode terminal region of the valve metal substrate and the conductive spacer are connected by the low-melting point conductive member. [Explanation of symbols]

[0083] 1, 2 Solid electrolytic capacitor 10 Capacitor element 11 Valve metal substrate 11a: First end of valve metal substrate 11b Second end of valve metal substrate 11c Bottom surface of valve metal base 12 Dielectric layer 13 Solid electrolyte layer 14 Conductive layer 15 Masking material 20 Encapsulating material 30 Sealing body 31 First end face of sealing body 32 Second end face of sealing body 33 Upper surface of encapsulant 34 Bottom surface of encapsulation body 35 First side of encapsulant 36 Second side of encapsulant 40 Anode external electrode 50 Cathode external electrode 60 Conductive spacer 61 Convex part (pillar part) 62 Low melting point conductive material (surface of convex part) 63a, 63b, 63c, 63d, 63e, 63f Convex part (pillar part) 64 Low melting point conductive material (top surface of conductive spacer) 70 Conductive spacer 71 Convex part (wall part) 72 Low melting point conductive material (surface of convex part) 74 Low melting point conductive material (upper surface of conductive spacer)

Claims

1. a capacitor element including a valve metal substrate having a first end, which is one end in a longitudinal direction, serving as an anode terminal region and a second end, which is the other end, serving as a cathode formation region; a sealing material that seals the capacitor element to form a sealed body; an anode external electrode provided on at least the bottom surface of the sealing body and electrically connected to the anode terminal region; a cathode external electrode provided on a surface of the sealing body and electrically connected to the cathode formation region, a conductive spacer is disposed between the bottom surface of the anode terminal region of the valve metal substrate and the anode external electrode; a solid electrolytic capacitor, wherein two or more protrusions protruding from the conductive spacer are provided at positions on either side of the anode terminal region of the valve metal substrate in the width direction;

2. 2. The solid electrolytic capacitor according to claim 1, wherein a low-melting point conductive member is provided on the surface of said protrusion at a position where said protrusion is adjacent to said anode terminal region of said valve metal substrate.

3. 3. The solid electrolytic capacitor according to claim 1, wherein the convex portion is a wall portion protruding from a side portion of the conductive spacer.

4. 3. The solid electrolytic capacitor according to claim 1, wherein the convex portion is a pillar portion protruding from the upper surface of the conductive spacer.

5. 3. The solid electrolytic capacitor according to claim 1, wherein a low-melting-point conductive member is provided between a bottom surface of the anode terminal region of the valve metal base and an upper surface of the conductive spacer, and the anode terminal region of the valve metal base and the conductive spacer are connected by the low-melting-point conductive member.

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