Electrolytic capacitor, method of manufacturing the same, and method of mounting the same

Abstract

To prevent the deterioration of leakage current characteristics caused by the winding deviation of a capacitor element.SOLUTION: The electrolytic capacitor (2) includes a sealing body (12) for sealing an outer case (10) in which the capacitor elements are housed, the sealing body (12) having a protrusion (24) facing an end surface of the capacitor elements, and a space (26) between an outer peripheral side of the end surface of the capacitor elements and the sealing body, wherein a static friction force between the separators and the cathode foils is 1. 2N or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to electrolytic capacitors such as solid electrolytic capacitors, and methods for manufacturing and mounting the same. [Background technology]

[0002] Regarding electrolytic capacitors, Japanese Patent Application Laid-Open No. 2010-239093 (Patent Document 1) discloses that natural cellulose fibers are used for the separator of a capacitor element, and that by winding the capacitor element with the natural cellulose fiber layer of the separator in contact with the winding shaft, an electrolytic capacitor can be provided that is free from shear. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-239093 Summary of the Invention [Problem to be solved by the invention]

[0004] Electrolytic capacitors, such as solid electrolytic capacitors, use capacitor elements with a separator between anode and cathode foils, and a solid electrolyte layer. Separators made of cellulose fiber or chemical fiber are used. Cellulose fiber is prone to significant deterioration in its properties, so chemical fiber separators are used to increase the capacity of solid electrolytic capacitors.

[0005] Compared to cellulosic fiber separators, chemical fiber separators have lower static friction with the cathode foil and are therefore more slippery. This can lead to loosening of the cathode foil or separator at the outermost periphery of the element during the winding process of the capacitor element. This loosening can cause the separator or cathode foil to protrude from the end face of the capacitor element (so-called miswinding of the wound element). If the protruding portion on the end face of the capacitor element solidifies in the solid electrolyte layer during the process of forming the solid electrolyte layer, a protrusion is formed on the outer periphery of the end face of the capacitor element. This protrusion is fragile and can be damaged by mechanical stress.

[0006] The exterior case that houses such a capacitor element and is sealed with a seal has little free space. Therefore, when the protrusion on the end face of the capacitor element comes into contact with the seal and is subjected to mechanical stress, the cathode foil inside the protrusion approaches the anode foil on the end face of the capacitor. In other words, the foil spacing between the anode foil and the cathode foil on the capacitor element is reduced. This increases leakage current, which affects the leakage current characteristics of the electrolytic capacitor.

[0007] During the process of mounting an electrolytic capacitor on a substrate (e.g., by reflow), the sealing body of the electrolytic capacitor thermally expands, and in capacitor elements having protrusions on the element end faces, the foil spacing between the anode foil and the cathode foil narrows, which can increase leakage current and deteriorate the leakage current characteristics of the electrolytic capacitor.

[0008] To some extent, contact or collision between the sealing member and the protruding portion of the element end face can be avoided by increasing the separator width. However, if the separator width is made wider relative to the foil width of the anode foil and cathode foil, the capacitor element length increases, preventing the electrolytic capacitor from being made thinner, so increasing the separator width is not desirable.

[0009] In response to such issues, the inventors of the present disclosure have discovered that avoiding contact or collision between the sealing body and the protrusions that arise on the end surfaces of the element due to misalignment caused by loosening of the capacitor element's winding can suppress leakage current and prevent deterioration of the leakage current characteristics of the electrolytic capacitor.

[0010] Such a problem has not been disclosed or suggested in the past, and the configuration disclosed in Patent Document 1 cannot solve such a problem.

[0011] Therefore, an object of the present disclosure is to prevent deterioration of leakage current characteristics caused by miswinding of a capacitor element, etc., based on the above-mentioned problems and findings. [Means for solving the problem]

[0012] To achieve the above object, the electrolytic capacitor of the present disclosure is an electrolytic capacitor including a capacitor element having a separator and a solid electrolyte layer interposed between an anode foil and a cathode foil, wherein a sealing body that seals an exterior case that houses the capacitor element has a convex portion that faces an end face of the capacitor element, and a space is provided between the outer periphery of the end face of the capacitor element and the sealing body, and the static friction force between the separator and the cathode foil is 1.2 N or less.

[0013] In this electrolytic capacitor, when a protruding portion including at least the cathode foil is formed on the outer periphery of the end face of the capacitor element, the protruding portion may be accommodated in the space.

[0014] In this electrolytic capacitor, the protruding length of the convex portion may be greater than the protruding length of the protruding portion including the cathode foil protruding toward the outer periphery of the end face of the capacitor element.

[0015] In this electrolytic capacitor, the static friction force between the separator and the cathode foil and the static friction force between the separator and the anode foil are in the following magnitude relationship: The static friction force between the separator and the cathode foil is less than the static friction force between the separator and the anode foil. is.

[0016] In this electrolytic capacitor, the basis weight (thickness x density) of the separator is 40 g / m 2 It may be less than.

[0017] In order to achieve the above object, the method for manufacturing an electrolytic capacitor disclosed herein is a method for manufacturing an electrolytic capacitor including a capacitor element having a separator and a solid electrolyte layer interposed between an anode foil and a cathode foil, and includes the steps of: setting the static friction force between the separator and the cathode foil to 1.2 N or less; and sealing an exterior case containing the capacitor element with a sealing body, and providing the sealing body with a protrusion facing an end face of the capacitor element to form a space between the sealing body and the outer periphery of the end face of the capacitor element.

[0018] This method of manufacturing an electrolytic capacitor may include a step of sealing the outer case with the sealing body including the convex portion, and when a protrusion including at least the cathode foil is formed and protrudes toward the outer periphery of the end face of the capacitor element, this protrusion may be accommodated in the space.

[0019] This method of manufacturing an electrolytic capacitor may include a step of setting the protruding length of the convex portion of the sealing body to be greater than the protruding length of the protruding portion including the cathode foil that protrudes toward the outer periphery of the end face of the capacitor element.

[0020] In order to achieve the above object, the mounting method for an electrolytic capacitor disclosed herein is a method for mounting an electrolytic capacitor including a capacitor element having a separator and a solid electrolyte layer interposed between an anode foil and a cathode foil, wherein a sealing body that seals an exterior case that houses the capacitor element has a convex portion facing an end face of the capacitor element, a space is provided between the outer periphery of the end face of the capacitor element and the sealing body that can accommodate a protrusion that protrudes toward the outer periphery of the end face of the capacitor element, and the static friction force between the separator and the cathode foil is 1.2 N or less, and the method includes the steps of: placing the electrolytic capacitor on a wiring member; and performing a heat treatment for soldering on the wiring member on which the electrolytic capacitor is mounted. [Effects of the Invention]

[0021] According to the present disclosure, any of the following effects can be obtained. (1) Even if a separator made of chemical fiber or a separator containing chemical fiber is used for the capacitor element, the adverse effects of miswinding of the capacitor element can be avoided, and deterioration of the leakage current characteristics of the electrolytic capacitor can be prevented.

[0022] (2) The convex portion of the sealing body facing the end face of the capacitor element supports the center side of the end face of the capacitor element, while the protrusion that occurs on the outer periphery of the end face of the capacitor element is accommodated in the space between the outer periphery of the end face of the capacitor element and the sealing body. This prevents contact between the protrusion of the capacitor element and the sealing body, and prevents the protrusion from being damaged by contact with the sealing body.

[0023] (3) It is possible to protect protrusions that occur on the outer periphery of the end faces of the capacitor element, thereby avoiding inconveniences such as damage to the protrusions that could cause the foil spacing between the anode foil and the cathode foil to be compromised, thereby avoiding an increase in leakage current from the capacitor element and preventing deterioration of the leakage current characteristics of the electrolytic capacitor.

[0024] (4) By using a separator made of chemical fiber or a separator containing chemical fiber, it is possible to increase the capacity of the electrolytic capacitor and reduce its weight and size. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a diagram illustrating the electrolytic capacitor and the manufacturing method thereof according to the present disclosure. [Figure 2] FIG. 2 is a diagram illustrating the electrolytic capacitor of the present disclosure and a mounting method thereof. [Figure 3] FIG. 3 is a diagram showing the correlation between the average basis weight and the leakage current and the rate of occurrence of winding misalignment in Examples 1-5. [Figure 4] FIG. 4 is a diagram showing the correlation between the average basis weight and the leakage current and the rate of occurrence of winding misalignment in Comparative Examples 1-5. DETAILED DESCRIPTION OF THE INVENTION

[0026] [One embodiment] 1 shows an electrolytic capacitor according to an embodiment of the present disclosure, its manufacturing method, and its mounting method. The configuration shown in FIG. 1 is an example, and the present disclosure is not limited to such a configuration.

[0027] <Electrolytic capacitor 2> This electrolytic capacitor 2 is an example of a solid electrolytic capacitor that uses a so-called wound element and a solid electrolyte, and includes a capacitor element 4, an anode-side lead terminal 6, a cathode-side lead terminal 8, an outer case 10, a sealing body 12, and a holder 13. In this embodiment, the holder 13 is provided, but the holder 13 may be omitted.

[0028] <Capacitor element 4> The capacitor element 4 is formed by winding a separator 18 between an anode foil 14 and a cathode foil 16 into a cylindrical shape, with a solid electrolyte layer formed between the anode foil 14 and the cathode foil 16. A stop tape 17 is wrapped around the outer periphery of the capacitor element 4. The anode foil 14 is made of a base foil made of a valve metal, which is subjected to a surface expansion process to form a dielectric oxide film. Valve metals include aluminum, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, antimony, and the like, and any of these metals is selected and formed into the base foil. The base foil is subjected to a surface expansion process to expand its surface, and a surface expansion layer is formed on the surface of the base foil using etching, sputtering, or other methods. Etching is performed, for example, by immersing the substrate foil in an acidic aqueous solution containing halogen ions, such as hydrochloric acid, and then passing a direct current (DC etching), an alternating current (AC etching), or both (AC / DC etching) to form a porous surface-expanding layer on the substrate foil, such as a concave-convex, tunnel-shaped pore, or spongy layer. This surface-expanding layer may contain countless pits or pores that penetrate the substrate foil (e.g., through-holes). Advanced etching is used to increase the capacitance of the capacitor element 4. Alternatively, instead of etching, a surface-expanding layer may be formed on the substrate foil by vapor deposition or sintering metal particles, or by vapor deposition or sintering metal particles on an etched substrate foil. After this surface-expanding process, a dielectric oxide film is formed on the surface of the surface-expanding layer of the substrate foil by chemical conversion treatment, thereby forming the anode foil 14.

[0029] The cathode foil 16 is made of a base foil selected from the valve metals described above, similar to the anode foil 14. The cathode foil 16 may be subjected to a surface-expanding treatment, or may be a plain foil that has not been subjected to a surface-expanding treatment. The surface-expanding treatment of the base foil is preferably performed by etching, sputtering, metal particle deposition, or sintering. An oxide film may be formed on the surface-expanding layer of the cathode foil 16, but it may not be formed. The oxide film may be formed intentionally or naturally (a natural oxide film). The oxide film is a thin oxide film formed by chemical conversion treatment in which a voltage is applied in a solution without halogen ions, such as an aqueous solution of adipic acid or boric acid. A natural oxide film is a thin oxide film formed when the base foil is exposed to air and reacts with oxygen.

[0030] The cathode foil 16 may have a conductive layer formed on the base foil. The conductive layer is laminated on the base foil. The conductive layer is preferably formed of an inorganic material having electrical conductivity, such as titanium, zirconium, tantalum, niobium, their nitrides or carbides, aluminum carbide, carbon material, and composites or mixtures thereof. Specific examples include a conductive layer of a carbon material, a conductive layer of titanium nitride, a conductive layer of titanium carbide, a conductive layer made of a mixture of titanium and a carbon material, and a conductive layer made of a composite of aluminum carbide (Al4C3) and titanium oxide (TiO2).

[0031] Conductive layers containing carbon materials are composed of a carbon material as the main material and additives such as binders and dispersants. Examples of carbon materials that can be used include activated carbon, carbon black, carbon nanohorns, amorphous carbon, natural graphite, artificial graphite, graphitized ketjen black, mesoporous carbon, and fibrous carbon. Activated carbon can be derived from natural plant tissues such as coconut husks, synthetic resins such as phenols, or fossil fuels such as coal, coke, or pitch. Examples of carbon black include ketjen black, acetylene black, channel black, and thermal black. Examples of fibrous carbon include carbon nanotubes and carbon nanofibers. Carbon nanotubes can be single-walled carbon nanotubes, which have a single graphene sheet, or multi-walled carbon nanotubes (MWCNTs), which have two or more graphene sheets curled coaxially to form multiple tube walls. The binder may be a resin binder such as styrene butadiene rubber, polyvinylidene fluoride, or polytetrafluoroethylene, and is bonded to the carbon material. The dispersing agent may be, for example, sodium carboxymethyl cellulose.

[0032] The separator 18 is, for example, made up of two sheets, which are placed on each surface of the anode foil 14 and wound together with the anode foil 14 and the cathode foil 16. The separator 18 is made of chemical fiber or contains chemical fiber. The width of the separator 18 is set wider than the width of the anode foil 14 and the cathode foil 16, so that the edges of the anode foil 14 and the cathode foil 16 are covered with the separator 18, thereby providing insulation between the anode foil 14 and the cathode foil 16.

[0033] Capacitor element 4 is impregnated with an electrolyte containing a conductive polymer, and this solid electrolyte layer is formed between anode foil 14 and cathode foil 16. The electrolyte layer may be a gel electrolyte, or may be a so-called hybrid electrolyte layer that includes an electrolytic solution in addition to a solid electrolyte containing a conductive polymer.

[0034] <Material for forming separator 18> The separator 18 is preferably made of chemical fibers such as nylon, acrylic, polyester, or aramid fibers. The separator 18 may be made of a material that is a mixture of multiple chemical fibers, or may be made of a mixture of nylon and acrylic fibers.

[0035] The separator 18 may be made of a material containing chemical fibers, such as a mixed fiber containing cellulosic fibers and chemical fibers, in which the ratio of chemical fibers to cellulosic fibers is, for example, 75% or more and 25% or less.

[0036] <Anode side lead terminal 6 and cathode side lead terminal 8> An anode-side lead terminal 6 is connected to the anode foil 14, and a cathode-side lead terminal 8 is connected to the cathode foil 16, with the anode-side lead terminal 6 and cathode-side lead terminal 8 extending from the end faces of the capacitor element 4. Both the anode-side lead terminal 6 and the cathode-side lead terminal 8 have columnar portions 20 that are flattened on the capacitor element 4 side and electrically connected to the anode foil or cathode foil by a connection method such as stitch connection. A lead portion 22 is connected to each columnar portion 20 by welding. Each lead portion 22 is a solderable metal wire.

[0037] <Outer case 10> The outer case 10 is an example of an outer case of the present disclosure. The outer case 10 is a cylindrical container with a bottom made of a valve metal material, such as aluminum, similar to the anode foil 14 and cathode foil 16 of the capacitor element 4, and although not shown, the bottom may be provided with a safety valve to prevent the outer case 10 from bursting due to gas generated from the capacitor element 4. After the sealing body 12 is inserted into the opening of the outer case 10, the outer case 10 is crimped, and the open end is curled to fit tightly against the outer surface of the sealing body 12.

[0038] <Sealing body 12> Sealing body 12 is an example of a sealing body of the present disclosure, and is a cylindrical body made of an elastic insulator such as rubber. Sealing body 12 has a protrusion 24 formed in opposition to the center of the end face of capacitor element 4. This protrusion 24 functions as a stopper that receives the end face of capacitor element 4 within exterior case 10.

[0039] A space 26 is formed around the protrusion 24 between the outer periphery of the end face of the capacitor element 4 and the sealing member 12. When a protrusion 28 protrudes from the outer periphery of the end face of the element due to, for example, miswinding of the capacitor element 4, as shown by the dashed line (phantom line), this space 26 allows the protrusion 28 to enter. More specifically, when a protrusion 28 including the cathode foil 16 protrudes from the outer periphery of the end face of the capacitor element 4, the end face of the capacitor element 4 is received by the protrusion 24, while the protrusion 28 is contained in the space 26, preventing the protrusion 28 from coming into contact with the sealing member 12 and being destroyed. More specifically, it is more preferable to provide a margin between the tip of the protrusion 28 and the sealing member 12 so that the protrusion 28 does not come into contact with the sealing member 12.

[0040] In addition, the anode side lead terminal 6 and the cathode side lead terminal 8 are led out to the end face side of the capacitor element 4 through through holes (not shown) in the sealing body 12 .

[0041] <Holder 13> This electrolytic capacitor 2 is provided with a holder 13 for forming the capacitor into chips. This holder 13 is placed on the sealing side of the outer case 10, and the anode side lead terminal 6 and the cathode side lead terminal 8, which are led out from the sealing body 12, pass through the holder 13, with the lead portions 22 bent in opposite directions at the bottom of the holder 13.

[0042] <Method of manufacturing electrolytic capacitor 2> The electrolytic capacitor 2 is manufactured through a process including a foil / separator cutting process, a terminal connection process, an element winding process, a chemical conversion process, an electrolyte layer forming process (for example, a solid electrolyte layer forming process), a sealing body forming process, an exterior packaging process, a chipping process, and an aging process.

[0043] Foil and separator cutting process: In this process, the substrate foil that has been subjected to surface expansion and chemical conversion treatment is cut to fit the capacitor element 4 to be manufactured, forming anode foil 14 and cathode foil 16. Similarly, a substrate made of chemical fiber is cut to form separator 18.

[0044] Terminal connecting step: In this step, the anode side lead terminal 6 is connected to the anode foil 14, and the cathode side lead terminal 8 is connected to the cathode foil 16, for example, by stitch connection.

[0045] Element Winding Process: In this process, a separator 18 is layered between an anode foil 14 and a cathode foil 16 and wound to form a capacitor element 4, which is a preliminary step in forming a solid electrolyte layer. If the static friction between the cathode foil 16 and the separator 18 is low, loosening of the winding occurs in the capacitor element 4, and this loosening appears as misalignment.

[0046] Chemical Conversion Step: In this step, the capacitor element 4 is subjected to a chemical conversion treatment in order to repair defects that have occurred in the oxide film of the anode foil 14.

[0047] Electrolyte layer formation step: In this step, the capacitor element 4 that has been dried after the chemical conversion treatment is impregnated with a solid electrolyte to form a solid electrolyte layer between the anode foil 14 and the cathode foil 16 of the capacitor element 4. If there is misalignment in the winding of the capacitor element 4, a protrusion 28 solidified by the solid electrolyte layer is formed on the end surface of the capacitor element 4.

[0048] Sealing body forming process: In this process, separate from the process of forming the capacitor element 4, sealing body 12 is formed from insulating rubber or the like. Protrusions 24 that protrude toward the end faces of capacitor element 4 are formed integrally with sealing body 12. By forming these protrusions 24, spaces 26 are formed around the peripheries of protrusions 24.

[0049] Packaging process: In this process, capacitor element 4, with lead wires inserted through insertion holes in the sealing body, is housed in exterior case 10, and the opening of exterior case 10 is sealed with sealing body 12. Protrusions 24 of sealing body 12 protrude toward the end face of capacitor element 4, forming space 26 in sealing body 12 on the outer periphery of the end face of capacitor element 4.

[0050] Then, outer case 10 is crimped around the periphery of sealing body 12, and the open end of outer case 10 is curled toward the center of the outer surface of sealing body 12, thereby sealing outer case 10 with sealing body 12. In this way, electrolytic capacitor 2 is formed.

[0051] Chip Forming Step: In this step, the electrolytic capacitor 2 is attached to a holder 13, and the electrolytic capacitor 2 for surface mounting is formed into a chip.

[0052] Aging step: In this step, the anode foil 14 is subjected to aging by power supplying in order to repair defects in the oxide film as a final treatment.

[0053] Other processes: In this process, the electrolytic capacitor 2 undergoes aging treatment, visual inspection, etc., before being commercialized.

[0054] <Relationship between increasing the capacity of electrolytic capacitor 2 and separator 18> In the electrolytic capacitor 2 of the present disclosure, a chemical fiber separator 18 is used in the capacitor element 4, and the separator 18 is thin, allowing for a smaller proportion of the capacitor element 4 occupied by the separator 18. The smaller proportion of the separator 18 allows for a larger number of turns of the anode foil 14 and the cathode foil 16 in the capacitor element 4, allowing for an increase in the capacity of the electrolytic capacitor 2.

[0055] <Basis weight of separator 18> The basis weight of the separator 18 is the product of the thickness and density of the separator 18 (g / m 2 ) and the separator 18 for 1m 2This is the weight (g) per unit area, which is a guideline for the thickness of the separator 18. To increase the capacity of the capacitor element 4, as will be shown in the experimental results described later, the separator 18 is made of a material with a weight of 60 (g / m 2 ) is sufficient, and 40 (g / m 2 It is more preferable to use one having a molecular weight of less than 1000 kJ / cm 2 .

[0056] <Static Friction Force Between the Separator 18 and the Anode Foil 14 or the Cathode Foil 16> The static friction force between the separator 18 and the cathode foil 16 is a friction force that acts in a direction that prevents movement between the separator 18 and the cathode foil 16. When a separator 18 made of chemical fiber is used, the static friction force with the cathode foil 16 is reduced. This static friction force varies depending on the surface properties of the cathode foil 16 that faces the separator 18. As shown in the experimental results described below, the static friction force between a cathode foil and a separator 18 with an uneven surface is greater than the static friction force between a cathode foil and a separator 18 with an uneven surface formed by surface expansion processing. The experimental results described below indicate that the static friction force between the separator 18 and the cathode foil 16 is preferably set to 1.2 N or less.

[0057] In contrast, the anode foil 14 has a larger oxide film formed on its surface than the cathode foil, and therefore has a larger static friction force with the separator 18. Therefore, the magnitude relationship between the static friction force between the separator 18 and the cathode foil 16 and the static friction force between the separator 18 and the anode foil 14 is as follows: The static friction force between the separator 18 and the cathode foil 16 is less than the static friction force between the separator 18 and the anode foil 14 .

[0058] Due to this magnitude relationship, the static friction force between separator 18 and cathode foil 16 is smaller than the static friction force between separator 18 and anode foil 14. As a result, loosening of the winding is likely to occur between cathode foil 16 and separator 18 on the outer periphery of capacitor element 4, resulting in misalignment of the winding.

[0059] <Relationship between static friction force and winding misalignment of capacitor element 4> If the static friction force between separator 18 made of chemical fiber and cathode foil 16 is small, loosening of the winding is likely to occur between separator 18 and cathode foil 16 during the winding process of capacitor element 4, and this loosening of the winding causes misalignment of capacitor element 4. Capacitor element 4 with misalignment undergoes the process of forming a solid electrolyte layer, and protrusion 28 is formed on the outer periphery of the end surface of capacitor element 4.

[0060] <Other Factors That Cause the Protrusion 28 of the Capacitor Element 4> As mentioned above, protrusion 28 is generated due to misalignment of the winding caused by loosening of the winding due to static friction between separator 18 and cathode foil 16 when capacitor element 4 is wound, and due to expansion of sealing body 12 during the mounting process. In the latter case, heating during the mounting process (reflow) causes sealing body 12 to expand toward capacitor element 4 due to thermal expansion, and stress from sealing body 12 pushes up capacitor element 4, resulting in protrusion 28 on the outer periphery of the element end face of capacitor element 4.

[0061] <Relationship between protrusion 28 of capacitor element 4 and leakage current characteristics> When an electrolyte layer is formed on capacitor element 4 through the process of forming a solid electrolyte layer, miswinding occurring on the outer periphery of the end face of capacitor element 4 creates protrusion 28, including cathode foil 16. While such protrusion 28 itself does not pose any problem in terms of the functionality of capacitor element 4, if protrusion 28 comes into contact with or collides with sealing body 12 and is subjected to stress from sealing body 12, the distance between anode foil 14 and cathode foil 16 of capacitor element 4 will be partially shortened. As a result, the leakage current of capacitor element 4 will increase, and the leakage current characteristics of electrolytic capacitor 2 will deteriorate.

[0062] <Functions of the protrusion 24 and the space 26 of the sealing body 12> Protrusion 24 protrudes from sealing body 12 toward the end face of capacitor element 4, and space 26 is formed on the outer periphery of the end face of capacitor element 4. Therefore, protrusion 24 serves to receive capacitor element 4 at the center of the end face, and space 26 serves to accommodate protrusion 28 formed on the outer periphery of the end face of capacitor element 4.

[0063] If the protruding length of the convex portion 24 is t1, the protruding length of the cathode foil of the protruding portion 28 occurring on the outer periphery of the end face of the capacitor element 4 is t2, and the distance (= margin width) between the longest part of the protruding portion 28 and the sealing body 12 facing the space 26 is t3, then this can be expressed by Equation 1.

[0064] t1=t2+t3...(Formula 1)

[0065] If t3 > 0, then t1 > t2. With such a setting, it is possible to prevent cathode foil 16, which is included in protrusion 28, from contacting or colliding with sealing body 12. If distance t3 is set to t3 > 0 or is increased, protrusion 28 can be received with ample space within space 26 of sealing body 12, and protrusion 28 can be housed within space 26 for protection.

[0066] <Mounting of electrolytic capacitor 2> 2 shows an example of an electrolytic capacitor 2 and its mounted state. The mounting method of this electrolytic capacitor 2 includes a step of placing the electrolytic capacitor 2, a reflow step, and the like.

[0067] 2, to mount the electrolytic capacitor 2, for example, a wiring board 30 is used as a wiring member, and conductor patterns 32-1 and 32-2 corresponding to the anode-side lead terminal 6 and cathode-side lead terminal 8 of the electrolytic capacitor 2 to be mounted are formed on this wiring board 30. The anode-side lead terminal 6 and cathode-side lead terminal 8 of the electrolytic capacitor 2 are positioned in accordance with the positions of the conductor patterns 32-1 and 32-2, with solder 34 interposed therebetween, and maintained in a temporarily fixed state.

[0068] Reflow process: After the electrolytic capacitor 2 is placed on the wiring board 30, a reflow process is performed as a heating process for soldering, and the anode side lead terminal 6 and the cathode side lead terminal 8 are electrically connected to the conductor patterns 32-1 and 32-2 of the wiring board 30 by soldering.

[0069] During such a reflow process, even if the electrolytic capacitor 2 is heated and the sealing body 12 expands, causing a protrusion 28 to form on the outer peripheral end face of the capacitor element 4, the protrusion 28 is received in the space 26, and no stress is applied to the cathode foil 16 contained in the protrusion 28, thereby preventing deterioration of the leakage current characteristics of the electrolytic capacitor 2, such as an increase in leakage current.

[0070] <Effects of the embodiment> According to this embodiment, one of the following effects can be obtained. (1) Since sealing body 12 has protrusion 24 and space 26 is provided between sealing body 12 and the outer periphery of the element end face of capacitor element 4, even if a protrusion 28 occurs due to miswinding on the outer periphery of capacitor element 4, protrusion 28 is received in space 26 and can be prevented from coming into contact with sealing body 12. As a result, an increase in leakage current from capacitor element 4 can be suppressed, and deterioration of the leakage current characteristics of electrolytic capacitor 2 can be avoided.

[0071] (2) Since the adverse effects of the protrusions 28 caused by misalignment of the separator 18 of the capacitor element 4 can be prevented, a chemical fiber having low static friction with the cathode foil 16 can be used for the separator 18. The use of the separator 18 made of chemical fiber can increase the capacity of the capacitor element 4, and therefore the capacity of the electrolytic capacitor 2.

[0072] (3) The static friction between separator 18 and cathode foil 16 can be set low, preventing the adverse effects of protrusions 28 caused by misalignment of separator 18 in capacitor element 4.

[0073] (4) By using a separator 18 with a low basis weight, the electrolytic capacitor 2 can be made high-capacity, lightweight, and compact. [Example]

[0074] For the examples and comparative examples, the static friction force between the separator 18 and the anode foil 14 or cathode foil 16 and its measurement method are described. The material of the separator 18, the type and surface properties of the anode foil 14 and cathode foil 16, the average static friction force between the anode foil 14 and separator 18, the average static friction force between the cathode foil 16 and separator 18, the rate of winding shear, and the average basis weight of the separator 18 are examined (conditions A, B, C, D, E, and F). Then, multiple electrolytic capacitors 2 (Examples 1, 2, 3, 4, and 5 and Comparative Examples 1, 2, 3, 4, and 5) were fabricated by combining different specifications of the sealing member 12 (the presence or absence of the protrusion 24 and the space 26), and the capacitance improvement rate and leakage current were measured and evaluated. The capacitance improvement rate represents the increase in capacitance per unit volume due to the use of a separator 18 made of chemical fiber or a separator 18 containing chemical fiber.

[0075] <Static friction and its measurement> In this disclosure, static friction force is used as an index for evaluating the ease of sliding between the separator 18 and the cathode foil 16, or between the separator 18 and the anode foil 14. This static friction force was measured in accordance with JIS Standard P-8147, "Test Method for the Coefficient of Friction of Paper and Paperboard," using a horizontal linear reciprocating sliding method. Specifically, a titanium-evaporated cathode foil (=without surface irregularities) or a titanium-evaporated cathode foil (=with surface irregularities due to surface expansion treatment) was placed on a sample stage as the cathode foil, a chemical fiber separator was placed on top of this cathode foil, a 200 g weight was placed on the separator, and the separator was pulled at a constant speed of 20 mm / min. This pulling force was measured with a load cell, and this measurement value was taken as the static friction force.

[0076] <Separator 18 material> Table 1 shows the materials *1 to *5 used for the separator 18.

[0077] [Table 1]

[0078] <Conditions A, B, C, D, E, F> The static friction force (average value) N and the occurrence rate of winding misalignment n% were measured for the separators 18, anode foils 14, and cathode foils 16 under conditions A, B, C, D, E, and F. The measurement results are shown in Table 2.

[0079] [Table 2]

[0080] In Table 2, material = material *1, material *2, material *3, material *4, material *5 are as described in Table 1.

[0081] In Table 2, the average basis weight of the separator is a value specified by the material, and is the value of 1 m 2 Weight per unit (g / m 2 ) and the separator thickness (m) and density (g / m 3 ) was calculated by multiplying

[0082] According to the measurement results, under condition A, the separator 18 = material *1, the average basis weight of material *1 = 11.2 g / m 2 In this case, the anode foil 14 was an etched foil, the surface texture of the anode foil 14 was "uneven", the cathode foil 16 was a titanium-deposited cathode foil, and the surface texture of the cathode foil 16 was "uneven", the static friction force (average value) between the anode foil 14 and the separator 18 was 1.2 N, the static friction force (average value) between the cathode foil 16 and the separator 18 was 1.1 N, and misalignment occurred in 3 of the 28 pieces, resulting in a misalignment occurrence rate n of 10.7%.

[0083] Condition B: Separator 18 = Material *1, average basis weight of Material *1 = 11.2 g / m 2 In this case, the anode foil 14 was an etched foil, the surface property of the anode foil 14 was "uneven", the cathode foil 16 was a titanium-deposited cathode foil, and the surface property of the cathode foil 16 was "not uneven", the static friction force (average value) between the anode foil 14 and the separator 18 was 1.2 N, the static friction force (average value) between the cathode foil 16 and the separator 18 was 0.6 N, and misalignment occurred in 9 out of 28 pieces, resulting in a misalignment occurrence rate n of n = 32.1%.

[0084] Comparing Condition A and Condition B, under Condition B, the surface property of the cathode foil 16 was "flat," and as a result, the static friction force (average value) between the cathode foil 16 and the separator 18 decreased from 1.1 N to 0.6 N, and it is estimated that the rate of occurrence of winding slippage n increased from 10.7% to 32.1%.

[0085] Condition C is when the separator 18 is material *5, the anode foil 14 is etched foil, the anode foil 14 has a surface texture of "uneven," the cathode foil 16 is titanium-deposited cathode foil, and the cathode foil 16 has a surface texture of "uneven." In this case, the static friction force (average value) between the anode foil 14 and the separator 18 is 1.3 N, the static friction force (average value) between the cathode foil 16 and the separator 18 is 1.4 N, and there were 0 out of 28 winding slippages, resulting in a winding slippage occurrence rate n of 0%. In other words, the material *5 is cellulose-based fiber, and it is estimated that using cellulose-based fiber for the separator 18 will completely eliminate winding slippage.

[0086] Condition D is separator 18 = material *2, average basis weight of material *2 = 40 g / m 2 In this case, the anode foil 14 was an etched foil, the surface property of the anode foil 14 was "uneven", the cathode foil 16 was a titanium-deposited cathode foil, and the surface property of the cathode foil 16 was "not uneven", the static friction force (average value) between the anode foil 14 and the separator 18 was 1.0 N, the static friction force (average value) between the cathode foil 16 and the separator 18 was 0.5 N, and misalignment occurred in 10 out of 28 pieces, resulting in a misalignment occurrence rate n of 35.7%.

[0087] Comparing condition D and condition A, the average basis weight of condition A is 11.2 g / m 2 Under condition D, the average basis weight is 40 g / m 2 The static friction force (average value) between the anode foil 14 and the separator 18 decreased from 1.2 N to 1.0 N, the static friction force (average value) between the cathode foil 16 and the separator 18 decreased from 1.1 N to 0.5 N, and the winding slippage occurrence rate n increased from 10.7% to 35.7%. This is presumably due to the increase in the average basis weight.

[0088] Comparing condition D and condition B, the average basis weight of condition B is 11.2 g / m 2Under condition D, the average basis weight is 40 g / m 2 The static friction force (average value) between the anode foil 14 and the separator 18 decreased from 1.2 N to 1.0 N, the static friction force (average value) between the cathode foil 16 and the separator 18 decreased from 0.6 N to 0.5 N, and the winding slippage occurrence rate n increased from 32.1% to 35.7%. This is presumably due to the increase in the average basis weight.

[0089] Condition E is separator 18 = material *3, average basis weight of material *3 = 17 g / m 2 In this case, the anode foil 14 was an etched foil, the surface property of the anode foil 14 was "uneven", the cathode foil 16 was a titanium-deposited cathode foil, and the surface property of the cathode foil 16 was "not uneven", the static friction force (average value) between the anode foil 14 and the separator 18 was 0.8 N, the static friction force (average value) between the cathode foil 16 and the separator 18 was 0.7 N, and misalignment occurred in 8 out of 28 pieces, resulting in a misalignment occurrence rate n of n = 27.6%.

[0090] Condition F is separator 18 = material *4, average basis weight of material *4 = 17.5 g / m 2 In this case, the anode foil 14 was an etched foil, the surface property of the anode foil 14 was "uneven", the cathode foil 16 was a titanium-deposited cathode foil, and the surface property of the cathode foil 16 was "not uneven", the static friction force (average value) between the anode foil 14 and the separator 18 was 0.8 N, the static friction force (average value) between the cathode foil 16 and the separator 18 was 0.7 N, and misalignment occurred in 8 out of 28 pieces, resulting in a misalignment occurrence rate n of n = 27.6%.

[0091] Comparing Condition E and Condition F, the average basis weight in Condition E was 17 g / m 2 In condition F, the average basis weight is 17.5 g / m 2 In contrast, under conditions E and F, the static friction force (average value) between the anode foil 14 and the separator 18 was 0.8 N, the static friction force (average value) between the cathode foil 16 and the separator 18 was 0.7 N, and the winding slippage occurrence rate n was 27.6%, with no difference between these. In other words, this level of difference in average basis weight does not affect the static friction force (average value) between the anode foil 14 and the separator 18, the static friction force (average value) between the cathode foil 16 and the separator 18, or the winding slippage occurrence rate n.

[0092] Comparing Condition D and Condition E, the average basis weight of Condition D is 40 g / m 2 Under condition E, the average basis weight is 17 g / m 2 As a result, the static friction force (average value) between the anode foil 14 and the separator 18 decreased from 1.0 N to 0.8 N, the static friction force (average value) between the cathode foil 16 and the separator 18 increased from 0.5 N to 0.7 N, and the winding slippage occurrence rate n decreased from 35.7% to 27.6%. This is presumably due to the decrease in the average basis weight.

[0093] Comparing Condition D and Condition F, the average basis weight of Condition D is 40 g / m 2 Under condition F, the average basis weight was 17.5 g / m 2 As a result, the static friction force (average value) between the anode foil 14 and the separator 18 decreased from 1.0 N to 0.8 N, the static friction force (average value) between the cathode foil 16 and the separator 18 increased from 0.5 N to 0.7 N, and the winding slippage occurrence rate n decreased from 35.7% to 27.6%, as in condition E. This is presumably due to the decrease in average basis weight.

[0094] Regarding material *1, under condition A, when the surface texture of cathode foil 16 is uneven, the static friction force between cathode foil 16 and separator 18 increases by about two times, and the rate of misalignment decreases to about one-third, compared to when there is no unevenness as in condition B. Also, as is clear from condition C, under material *5, if the static friction force (average value) between cathode foil 16 and separator 18 is 1.4 N or higher, misalignment will not occur in the capacitor element.

[0095] As is clear from the comparison of conditions A to F, an increase in the average basis weight of the separator reduces static friction, resulting in an increase in winding slippage, indicating a close relationship between average basis weight, static friction, and winding slippage. In other words, it is inferred that reducing the average basis weight of the separator increases static friction and is effective in preventing winding slippage of the capacitor element.

[0096] <Examples 1, 2, 3, 4, and 5, and Comparative Examples 1, 2, 3, 4, and 5> Table 3 shows the measurement results of the capacitance improvement rate and leakage current related to winding misalignment for N=28 samples of electrolytic capacitor 2 (Examples 1, 2, 3, 4, 5 and Comparative Examples 1, 2, 3, 4, 5) relating to the combinations of conditions A, B, D, E, F and sealing body specifications. In Table 3, material = material *1, material *2, material *3, material *4 are as shown in Tables 1 and 2.

[0097] [Table 3]

[0098] Regarding the "sealing body specifications" in Table 3, "protrusion" corresponds to the protrusion 24 of the sealing body 12 (Figures 1 and 2), "flat" corresponds to the case where the sealing body 12 does not have the protrusion 24 (Figures 1 and 2), and "space" corresponds to the space 26 (Figures 1 and 2).

[0099] In Example 1, the separator 18 is made of material *1 under condition A, and the average basis weight of material *1 is 11.2 g / m 2 , the sealing body specification = "protrusion · space: present" electrolytic capacitor, Comparative Example 1 is condition A, separator 18 is material * 1, average basis weight of material * 1 = 11.2 g / m 2 , and the sealing body specification is flat electrolytic capacitor.

[0100] Comparing Example 1 and Comparative Example 1, the capacity improvement rate was 125% in both cases. Example 1 had an initial leakage current of 3 μA, which increased slightly to 4 μA after reflow. However, Comparative Example 1 had an initial leakage current of 2 μA, which increased dramatically to 400 μA after reflow. This is presumably due to the sealant specifications. In other words, because the sealant specifications in Comparative Example 1 were flat, reflow caused misalignment in the capacitor element 4, which is presumably what increased the leakage current.

[0101] In Example 2, the separator 18 is made of material *1 under condition B, and the average basis weight of material *1 is 11.2 g / m 2 , sealing body specification = "protrusion · space: present" electrolytic capacitor 2, Comparative Example 2 is condition B, separator 18 is material * 1, average basis weight of material * 1 = 11.2 g / m2 , and the sealing body specification is flat electrolytic capacitor.

[0102] Comparing Example 1 and Example 2, the capacity improvement rate was 125% in both, with Example 1 having an initial leakage current of 3 μA and a slight increase to 4 μA after reflow, and Example 2 having an initial leakage current of 4 μA and an increase to 12 μA after reflow. This is presumably because, while the sealing body specifications were the same, Example 1 was under condition A and had uneven surface texture of the cathode foil, while Example 2 was under condition B and had no uneven surface texture of the cathode foil. This caused a slight misalignment in the winding of capacitor element 4, which increased the leakage current.

[0103] Comparing Example 2 and Comparative Example 2, both share Condition B and exhibit a 125% capacity improvement rate. Example 2 exhibits an initial leakage current of 4 μA, increasing to 12 μA after reflow. Comparative Example 2 exhibits a decrease in initial leakage current to 3 μA, but a dramatic increase in leakage current to 380 μA after reflow. This is presumably due to the sealant specifications. In other words, because the sealant specifications in Comparative Example 2 are flat, reflow causes misalignment of the capacitor element 4, presumably increasing the leakage current.

[0104] In Example 3, the separator 18 is made of material *3 under condition E, and the average basis weight of material *3 is 17 g / m 2 , and the sealing body specification = "protrusion and space: present" is electrolytic capacitor 2, and Comparative Example 3 is condition E, separator 18 is material *3, average basis weight of material *3 = 17 g / m 2 , and the sealing body specification is flat electrolytic capacitor.

[0105] Comparing Example 3 and Comparative Example 3, the capacity improvement rate increased to 139% in both cases. The initial leakage current in Example 3 was 4 μA, and the leakage current after reflow increased to 10 μA. However, the initial leakage current in Comparative Example 3 decreased to 3 μA, and the leakage current after reflow increased dramatically to 405 μA. This is presumably due to the seal specifications. In other words, because the seal specifications in Comparative Example 3 were flat, misalignment occurred in the capacitor element 4 during reflow, which is presumably what increased the leakage current.

[0106] In Example 4, the separator 18 is made of material *4 under condition F, and the average basis weight of material *4 is 17.5 g / m 2 , Electrolytic capacitor 2 with sealing body specification = "Protrusion and space: present", Comparative Example 4, Condition F, separator 18 is made of material *4, average basis weight of material *4 = 17.5 g / m 2 , and the sealing body specification is flat electrolytic capacitor.

[0107] Comparing Example 4 and Comparative Example 4, the capacity improvement rate in both cases was 138%, and the material of the separator 18 in both cases was material *4 and the average basis weight was 17.5 g / m 2 In Example 4, the initial leakage current was 4 μA, but increased to 7 μA after reflow. In Comparative Example 4, the initial leakage current was reduced to 3 μA, but the leakage current after reflow increased dramatically to 416 μA. This is presumably due to the seal specifications. In other words, in Comparative Example 4, the seal specifications were flat and the cathode foil was smooth. As a result, misalignment occurred in the capacitor element 4 during reflow, which is presumably what increased the leakage current.

[0108] In Example 5, the separator 18 is made of material *2 under condition D, and the average basis weight of the material *2 is 40 g / m 2 , Electrolytic capacitor 2 with sealing body specification = "protrusion and space: present", Comparative Example 5, Condition D, separator 18 is material *2, average basis weight of material *2 = 40 g / m 2 , and the sealing body specification is flat electrolytic capacitor.

[0109] Comparing Example 5 and Comparative Example 5, the capacity improvement rate is 100% in both cases, and the initial leakage current of Example 5 is 3 μA, and the leakage current after reflow increases to 10 μA. However, the initial leakage current of Comparative Example 5 increases to 4 μA, but the leakage current after reflow only increases slightly to 11 μA. In other words, the material of the separator 18 is material *2, and the average basis weight is 40 g / m. 2 Therefore, it is presumed that even if winding misalignment occurs, the leakage current may not necessarily increase.

[0110] Comparing Examples 1 to 4, even if the separator 18 is made of a material of *1, *3, or *4, there is no significant difference in the average basis weight, and as a result, there is no increase in leakage current. Also, in Example 5, the separator 18 is made of a material of *2, and the average basis weight is 40 g / m. 2 Similarly, there is no increase in the initial leakage current even when the average basis weight is increased to 11.2 g / m. 2 from 40 g / m 2 It is estimated that even if the average basis weight is increased to 17.5 g / m, there will be no increase in leakage current after reflow. 2 or average basis weight 40 g / m 2 For example, an average basis weight of 20 g / m 2 or average basis weight 30g / m 2 Similarly, it can be inferred that there is no increase in leakage current.

[0111] <Degree of Margin of Space 26 for Protrusion 28 Including Cathode Foil 16> In the electrolytic capacitor 2 used in Examples 1 and 2, the protrusion length t1 of the convex portion 24 of the sealing member 12 is 0.15 mm, and the protrusion length t2 of the cathode foil 16 protruding from the capacitor element 4 is 0.05 to 0.1 mm. The width in the height direction of the space 26 formed between the peripheral element end face of the capacitor element 4 and the sealing member 12 depends on the protrusion length t1 of the convex portion 24. Therefore, a margin of distance t3 is provided on the space 26 side to prevent the cathode foil 16 from colliding with the sealing member 12. For example, a margin of approximately t3 = 0.05 mm is provided.

[0112] <Correlation between average basis weight and leakage current and rate of occurrence of winding misalignment in Examples 1-5 and Comparative Examples 1-5> Figure 3 shows the average basis weight (g / m) on the horizontal axis. 2 The left vertical axis is leakage current μA, and the right vertical axis is winding misalignment occurrence rate n, and the correlation between the average basis weight and leakage current and winding misalignment occurrence rate of Examples 1-5 in Table 3 is shown.

[0113] Similarly, Figure 4 shows the average basis weight (g / m) on the horizontal axis. 2 The left vertical axis is leakage current μA, and the right vertical axis is winding misalignment occurrence rate n, and the correlation between the average basis weight and leakage current and winding misalignment occurrence rate of Comparative Examples 1-5 in Table 3 is shown.

[0114] For Figures 3 and 4, the average basis weight (g / m) 2 The winding slippage occurrence rate n shows almost the same increase and decrease relationship between Example 1-5 and Comparative Example 1-5.

[0115] Regarding the initial value of leakage current, in Examples 1-5, the average basis weight (g / m) 2 In Comparative Example 1-5, the average basis weight g / m 2 In contrast, in Examples 1-5, the leakage current after reflow increased slightly with increasing average basis weight (g / m). 2 On the other hand, in Comparative Example 1-5, the leakage current after reflow increased significantly, and the average basis weight was 17.5 g / m 2 The boundary is 40.0 g / m 2 The graph shows a decreasing trend toward

[0116] As is clear from Figures 3 and 4, the average basis weight is 17.5 g / m 2 and average basis weight = 40.0 g / m 2 Between these, average basis weight = 20-30g / m 2 The average basis weight can be assumed to be 20-30 g / m 2 Therefore, it is possible to predict the value of the winding slippage rate n and leakage current μA for the separator. 2 and more preferably less than 30 g / m2 More preferably, 20 g / m or less 2 The following is the result.

[0117] <Effects of the Example> According to the embodiment described above, any of the following effects can be obtained. (1) Even if a protrusion 28 occurs due to miswinding on the outer periphery of the end face of the capacitor element 4, the protrusion 28 can be accommodated in the space 26 and prevented from coming into contact with the sealing body 12. As a result, an increase in leakage current can be suppressed, and deterioration of the leakage current characteristics of the electrolytic capacitor 2 can be avoided.

[0118] (2) Since the adverse effects of the protrusions 28 caused by misalignment of the separator 18 of the capacitor element 4 can be prevented, a chemical fiber that has low static friction with the cathode foil 16 can be used for the separator 18. Using a separator 18 made of chemical fiber can increase the capacity of the capacitor element 4, and ultimately the capacity of the electrolytic capacitor 2.

[0119] (3) The static friction force between separator 18 and cathode foil 16 is set to 1.2 N or less, which prevents the adverse effects of protrusions 28 caused by misalignment of separator 18 in capacitor element 4.

[0120] (4) Basis weight 40 (g / m 2 ) can be used to increase the capacity of the capacitor element 4, and therefore the electrolytic capacitor 2.

[0121] Other Embodiments This disclosure can be understood at various levels and variations, from higher concepts to lower concepts.

[0122] (1) With respect to the convex portion 24 of the sealing body 12 and the space 26 formed between the sealing body 12 and the outer peripheral side of the end face of the capacitor element 4, when a protrusion 28 including the cathode foil 16 protruding from the outer peripheral side of the end face of the capacitor element 4 is formed, the protrusion 28 is received in the space 26, but the present disclosure is not limited to this.

[0123] (2) The space 26 also functions as a heat dissipation space for the capacitor element 4.

[0124] (3) The cathode foil 16 may be a base foil that has not been subjected to surface expansion treatment and has a carbon layer on the surface thereof.

[0125] (4) Although a mixed separator containing 75% chemical fiber and 25% cellulosic fiber is exemplified, the separator is not limited to these numerical values.

[0126] (5) In the above embodiment, a process of performing a reflow process on a wiring member (such as wiring board 30) is exemplified as a method for mounting electrolytic capacitor 2, but the present disclosure is not limited to such a reflow process. It goes without saying that the effects of heat treatment due to any soldering process can be avoided, such as a flow soldering process in which molten solder is directly applied to the anode-side lead terminal 6 and cathode-side lead terminal 8 of electrolytic capacitor 2 formed as a lead type and the conductor pattern, or a reflow soldering process in which cream solder is melted and applied to the anode-side lead terminal 6 and cathode-side lead terminal 8 of electrolytic capacitor 2 formed as a chip type (such as in the above embodiment) and the conductor pattern.

[0127] As described above, the most preferred embodiment of the present disclosure has been described. The present disclosure is not limited to the above description. Various modifications and changes are possible for those skilled in the art based on the gist of the present disclosure as set forth in the claims or disclosed in the description for carrying out the invention. It goes without saying that such modifications and changes are included within the scope of the present disclosure. [Industrial Applicability]

[0128] The present disclosure is useful in that it is possible to increase the capacity of an electrolytic capacitor and reduce its weight or size by using a separator containing chemical fibers, and even if a protrusion including a cathode foil occurs on the end face of a capacitor element, the end face of the capacitor element is received by the convex portion of the sealing body, while the protrusion can be received in the space formed between the outer periphery of the end face of the capacitor element and the sealing body, thereby preventing damage to the protrusion and preventing deterioration of the leakage current characteristics of the electrolytic capacitor. [Explanation of symbols]

[0129] 2 electrolytic capacitors 4 Capacitor elements 6 Anode side lead terminal 8 Cathode side lead terminal 10 Outer case 12 Sealing body 13 Holder 14 Anode foil 16 Cathode foil 17 Element winding tape 18 Separator 20 Column part 22 Lead section 24 Convex part 26 Space 28 Protrusion 30 Wiring board 32-1, 32-2 Conductor pattern 34 Solder

Claims

1. An electrolytic capacitor including a capacitor element in which a separator and a solid electrolyte layer are interposed between an anode foil and a cathode foil, a sealing body that seals an exterior case containing the capacitor element has a protrusion that faces an end face of the capacitor element, and a space is provided between the sealing body and an outer periphery of the end face of the capacitor element; The static friction force between the separator and the cathode foil is 1.2 N or less. Electrolytic capacitor.

2. 2. The electrolytic capacitor according to claim 1, wherein when a protrusion including at least the cathode foil is formed and protrudes toward the outer periphery of the end face of the capacitor element, the protrusion is accommodated in the space.

3. 3. The electrolytic capacitor according to claim 2, wherein the protruding length of the convex portion is greater than the protruding length of the protruding portion including the cathode foil protruding toward the outer periphery of the end face of the capacitor element.

4. The magnitude relationship between the static friction force between the separator and the cathode foil and the static friction force between the separator and the anode foil is:

3. The electrolytic capacitor according to claim 1, wherein the static friction force between the separator and the cathode foil is less than the static friction force between the separator and the anode foil.

5. The basis weight (thickness x density) of the separator is 40 g / m 2 The electrolytic capacitor according to claim 1 or claim 2, wherein the .lambda.

6. A method for manufacturing an electrolytic capacitor including a capacitor element in which a separator and a solid electrolyte layer are interposed between an anode foil and a cathode foil, the method comprising: setting the static friction force between the separator and the cathode foil to 1.2 N or less; a step of sealing the exterior case containing the capacitor element with a sealing body, and providing the sealing body with a protrusion facing the end face of the capacitor element to form a space between the sealing body and the outer periphery of the end face of the capacitor element; A method for manufacturing an electrolytic capacitor, comprising:

7. 7. The method for manufacturing an electrolytic capacitor according to claim 6, further comprising the step of sealing the exterior case with the sealing body including the convex portion, wherein when a protrusion including at least the cathode foil is formed protruding toward the outer periphery of an end face of the capacitor element, the protrusion is accommodated in the space.

8. 8. The method for manufacturing an electrolytic capacitor according to claim 7, further comprising a step of setting a protrusion length of the convex portion of the sealing body to be greater than a protrusion length of the protrusion including the cathode foil that protrudes toward the outer periphery of the end face of the capacitor element.

9. A method for mounting an electrolytic capacitor including a capacitor element in which a separator and a solid electrolyte layer are interposed between an anode foil and a cathode foil, the method comprising: a step of disposing the electrolytic capacitor on a wiring member, the step including providing a sealing body that seals an exterior case that houses the capacitor element with a protrusion facing the end face of the capacitor element, providing a space between the outer periphery of the end face of the capacitor element and the sealing body that can accommodate the protrusion protruding toward the outer periphery of the end face of the capacitor element, the static friction force between the separator and the cathode foil being 1.2 N or less; a step of subjecting the wiring member on which the electrolytic capacitor is installed to a heat treatment for soldering; A method for mounting an electrolytic capacitor, comprising:

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