Solid electrolytic capacitor and method for manufacturing the same

Abstract

To provide a solid electrolytic capacitor having capacitor characteristics which are stable for a long time.SOLUTION: The present invention relates to a solid electrolytic capacitor comprising a capacitor element which is stored in a bottomed cylindrical case. The capacitor element includes: water soluble first polymers provided on a surface of an anode body and a surface of a cathode body; and water dispersible second polymers disposed on the surface of the anode body and the surface of the cathode body where the first polymers are provided. The second polymer electrically connects the anode body and the cathode body. An ordinary temperature solid material obtained by dissolving an electrolyte in a solvent which is a solid at a first temperature or lower and is dissolved when the temperature rises to a second temperature or higher that is higher than the first temperature is disposed between the surface of the anode body and the surface of the cathode body and between an inner surface of the case and an outer surface of the capacitor element.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a solid electrolytic capacitor and a method for manufacturing a solid electrolytic capacitor. [Background technology]

[0002] A conventional capacitor includes, for example, a case with an opening for inserting the element, a capacitor element housed in the case, and a sealing body attached to the opening. The capacitor element is configured by winding an elongated anode and an elongated cathode facing each other with a separator interposed therebetween.

[0003] Furthermore, of the opposing surfaces of the anode and cathode, at least the opposing surface of the anode is formed as an oxide film. Furthermore, a water-dispersible conductive polymer is disposed between the anode and cathode. Furthermore, an electrolyte is generally provided between the anode and cathode (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-010657 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional capacitors have the problem that, in the usage environment, heat, vibrations, etc. are applied to the capacitor element, and over long-term use, the electrolyte evaporates through the sealing body, resulting in a deterioration of the capacitor characteristics.

[0006] An object of the present invention is to provide a solid electrolytic capacitor having stable capacitor characteristics over a long period of time and a method for manufacturing the solid electrolytic capacitor. [Means for solving the problem]

[0007] To achieve the above object, the present invention provides a solid electrolytic capacitor comprising: a cylindrical case with a bottom and an opening; a capacitor element formed by winding an anode body and a cathode body with a separator interposed therebetween and housed in the case; and a sealing member that seals the opening. The capacitor element comprises a water-soluble first polymer provided on the surface of the anode body and the surface of the cathode body; and a water-dispersible second polymer provided on the surface of the anode body on which the first polymer is provided and on the surface of the cathode body on which the first polymer is provided. The second polymer electrically connects the surface of the anode body to the surface of the cathode body. Between the surface of the anode body and the surface of the cathode body of the capacitor element and between the inner surface of the case and the outer surface of the capacitor element, a room-temperature solid substance is disposed, the room-temperature solid substance being formed by dissolving an electrolyte in a solvent that is solid at or below a first temperature and melts when heated to or above a second temperature higher than the first temperature.

[0008] In the solid electrolytic capacitor of the present invention having the above configuration, the first polymer may be provided on a surface of the anode body, a surface of the cathode body, and a surface of the separator.

[0009] Furthermore, in the solid electrolytic capacitor of the present invention having the above configuration, the first temperature is 30°C.

[0010] Furthermore, in the solid electrolytic capacitor having the above configuration according to the present invention, the solvent contains at least one of polyethylene glycol, polyhydric alcohol, glycerin fatty acid ester, and sugar.

[0011] Furthermore, in the solid electrolytic capacitor of the present invention having the above-described configuration, the second temperature of the solvent is 50°C.

[0012] Furthermore, in the solid electrolytic capacitor of the present invention having the above configuration, the solvent contains at least one of PEG2000, PEG4000, PEG6000, PEG10000, PEG20000, 1,2-dodecanediol, 1,12-dodecanediol, polyglyceryl-6 stearate, polyglyceryl-6 tristearate, polyglyceryl-4 pentastearate, polyglyceryl-10 decastearate, polyglyceryl-10 hepta(behenate / stearate), xylitol, and sorbitol.

[0013] Furthermore, in the solid electrolytic capacitor of the present invention having the above configuration, the electrolyte contains at least one of malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, decanedicarboxylic acid, tartronic acid, fumaric acid, maleic acid, citraconic acid, malic acid, tartaric acid, phthalic acid, nitrophthalic acid, citric acid, tricarbanilic acid, pyromellitic acid, boric acid, phosphoric acid, borodisalicylic acid, borodiglycolic acid, trinitrophenol, hydroxynitrophenol, hydroxynitrobenzoic acid, and sulfosalicylic acid, or at least one of ammonia, monoethylamine, diethylamine, triethylamine, trimethylamine, N,N-dimethylethylamine, N,N-diethylmethylamine, monoethanolamine, diethanolamine, triethanolamine, benzylamine, naphthylamine, morpholine, aniline, acetanilide, phenanthroline, caffeine, and imidazole.

[0014] Furthermore, in the solid electrolytic capacitor of the present invention having the above configuration, the sealing body is made of rubber or resin.

[0015] In order to achieve the above object, the method for manufacturing a solid electrolytic capacitor of the present invention includes a capacitor element manufacturing process in which a capacitor molded body formed by winding an anode body and a cathode body with a separator interposed therebetween is immersed in a solution containing a water-soluble first polymer and a water-dispersible second polymer, and the capacitor molded body is pulled out of the solution and dried to manufacture a capacitor element; and an insertion process in which the capacitor element is inserted into a case containing a room-temperature solid material that has been heated to a second temperature or higher and melted, and a portion of the melted room-temperature solid material is allowed to penetrate into the capacitor element. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a solid electrolytic capacitor having stable capacitor characteristics over a long period of time and a method for manufacturing the solid electrolytic capacitor. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a side cross-sectional view of a solid electrolytic capacitor according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the capacitor element of the solid electrolytic capacitor shown in FIG. [Figure 3] FIG. 2 is a schematic diagram showing a solution used in the immersion step. [Figure 4] FIG. 1 is a schematic diagram showing a dipping step. [Figure 5] FIG. 2 is a schematic diagram showing a drying process. [Figure 6] 1 is a diagram showing a melting process in which a solid substance at room temperature is heated and melted. FIG. [Figure 7] FIG. 1 is a diagram showing a solidification step in which a room temperature solid substance is solidified by cooling. [Figure 8] FIG. 1 is a diagram showing a pulverization step for pulverizing a solidified room-temperature solid material. [Figure 9] FIG. [Figure 10] 1 is a cross-sectional view of a case containing powder of a substance that is solid at room temperature. [Figure 11]1 is a cross-sectional view of a case containing a liquid, room-temperature solid substance. [Figure 12] 10 is a cross-sectional view showing a state in which a capacitor element is housed in a case containing a liquid substance that is solid at room temperature. FIG. [Figure 13] 1 is a cross-sectional view showing the case 1 in which the solidified room-temperature solid material and the capacitor element are housed. FIG. [Figure 14] FIG. 10 is a cross-sectional view showing a step of attaching a sealing body to a case. [Figure 15] FIG. 10 is a cross-sectional view of a case with a sealing body attached and a recess formed therein. [Figure 16] FIG. 10 is a diagram illustrating an aging process. [Figure 17] FIG. 10 is a diagram showing a solid electrolytic capacitor according to another embodiment of the present invention. [Figure 18] FIG. 4 is a diagram showing the results of an experiment to confirm the ability to repair an oxide film in the solid electrolytic capacitor of the first example. DETAILED DESCRIPTION OF THE INVENTION

[0018] A solid electrolytic capacitor according to one embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a side cross-sectional view of a solid electrolytic capacitor according to one embodiment of the present invention. Fig. 2 is an exploded perspective view of a capacitor element 3 of the solid electrolytic capacitor shown in Fig. 1.

[0019] The solid electrolytic capacitor A has a case 1, a capacitor element 3, and a sealing body 4. The case 1 is made of a metal such as aluminum and has a cylindrical shape with a circular cross section and a bottom. The case 1 has a bottom 1a and a tubular portion 1b. The bottom 1a is disk-shaped. The tubular portion 1b is connected to the radial outer edge of the bottom 1a and extends in the axial direction. The side connected to the bottom 1a is referred to as the upper side. The tubular portion 1b has an opening 1c at its upper end. In other words, the case 1 has one end of the tubular portion 1b closed by the bottom 1a and the other end open to the opening 1c.

[0020] Capacitor element 3 is housed in case 1 and has an anode body 8 used as an anode and a cathode body 9 (see FIG. 2) used as a cathode. An anode lead terminal 10 and a cathode lead terminal 11 are connected to anode body 8 and cathode body 9, respectively. Capacitor element 3 is cylindrical, and anode lead terminal 10 and cathode lead terminal 11 extend in the axial direction from one axial end.

[0021] The sealing body 4 is formed into a disk shape from a molded product made of an insulating elastic material such as rubber. The sealing body 4 has a pair of through holes 4a, 4b. With the sealing body 4 placed in the opening 1c of the case 1, the peripheral surface of the case 1 is drawn to form a recess 5, which fixes the sealing body 4 in place. Furthermore, the open end of the case 1 is bent inward to form a contact portion 6.

[0022] Sealing body 4 is fixed to opening 1c of case 1 by recess 5 and abutment portion 6. In other words, opening 1c of case 1 is sealed by sealing body 4. Sealing body 4 has through holes 4a and 4b that penetrate in the thickness direction. When capacitor element 3 is housed in case 1, anode lead terminal 10 and cathode lead terminal 11 of capacitor element 3 are inserted into through holes 4a and 4b. In this way, capacitor element 3 is fixed to case 1.

[0023] 1 , in solid electrolytic capacitor A, a room-temperature solid material 2 is disposed between anode body 8 and cathode body 9. More specifically, room-temperature solid material 2 is disposed between the surface of anode body 8 and the surface of cathode body 9, and between the surface of separator 7, the inner surface of case 1, and the outer surface of capacitor element 3.

[0024] Next, the capacitor element 3 will be described in detail. As shown in Fig. 2, the capacitor element 3 is formed by winding a long anode body 8 and a long cathode body 9 with an insulating separator 7 interposed therebetween. In the capacitor element 3, the separator 7 is disposed on the outermost periphery, and the separator 7 is fixed with tape 12. Note that in the capacitor element 3 according to this embodiment, the anode body 8 is an anode, and the cathode body 9 is a cathode.

[0025] For example, the anode body 8 and the cathode body 9 are made of aluminum. An oxide film (not shown) is disposed on the surface of each of the anode body 8 and the cathode body 9. The oxide film on the anode body 8 side and the oxide film on the cathode body 9 are both obtained by anodizing the aluminum electrode body in an electrolyte (chemical conversion treatment), and the thickness of each film is proportional to the applied voltage. The thickness of the oxide film on the anode body 8 is made thicker than the thickness of the oxide film on the cathode body 9. Furthermore, it is sufficient that an oxide film is formed on at least the surface of the anode body 8; it is not necessary for an oxide film to be formed on the surface of the cathode body 9.

[0026] As described above, anode lead terminal 10 is electrically and mechanically connected to anode body 8. Cathode lead terminal 11 is electrically and mechanically connected to cathode body 9.

[0027] The room-temperature solid substance 2 is, for example, a room-temperature solid substance that is solid at room temperature. Here, room temperature is, for example, 30°C. To explain in more detail, the room-temperature solid substance 2 has a solvent 21 that is solid at or below a first temperature (for example, room temperature: here, 30°C) and melts when heated to a predetermined temperature (melting point) that exceeds a second temperature higher than the first temperature, and an electrolyte 22 dissolved in the solvent (see FIG. 6). Details of the room-temperature solid substance 2 will be described later.

[0028] The solid electrolytic capacitor A has the configuration described above. Next, the manufacturing procedure for the solid electrolytic capacitor A will be described with reference to the drawings. Fig. 3 is a schematic diagram showing the solution 14 used in the immersion step. Fig. 4 is a schematic diagram showing the immersion step. Fig. 5 is a schematic diagram showing the drying step.

[0029] 2 , from the outside in, separator 7, cathode body 9 connected to cathode lead terminal 11, and separator 7 and anode body 8 connected to anode lead terminal 10 are stacked and arranged, and wound with anode body 8 on the inside. Thereafter, stop tape 12 is attached to the outer periphery of separator 7 arranged on the outermost side, and a cylindrical molded capacitor 31 is molded.

[0030] The molded capacitor body 31 thus formed is immersed in a solution 14 containing a water-soluble first polymer 141 and a water-dispersible second polymer 142 (immersion step, see FIG. 4). This immersion step is performed under reduced pressure. This allows the solution 14 to permeate the interior of the molded capacitor body 31.

[0031] The solution 14 will now be described in detail. As shown in FIG. 3, the solution 14 is obtained by placing a water-soluble first polymer 141 and a water-dispersible second polymer 142 in a container 13 and stirring them. Setting the ratio of the first polymer 141 in the solution 14 to 10% to 90% is preferable because it increases the capacitance of the capacitor element 3. Furthermore, setting the ratio of the first polymer 141 in the solution 14 to 15% to 85% is more preferable because it reduces the ESR.

[0032] The first polymer 141 is a water-soluble conductive polymer, more specifically, a self-doping water-soluble conductive polymer, such as Selftron manufactured by Tosoh Corporation. The second polymer 142 is, for example, a water-dispersible polymer dispersion. Examples of the second polymer 142 include Teikatron manufactured by Teika Corporation, Sebulgida manufactured by Shin-Etsu Polymer Co., Ltd., and Clevios manufactured by Heraeus K.K.

[0033] 5, the molded capacitor body 31 is removed from the container 13. The molded capacitor body 31 is then left in a drying step in which it is left in an atmosphere at 125°C for 30 minutes to dry, thereby producing a capacitor element 3 (first capacitor element manufacturing step). Note that in the drying step shown in FIG. 5, drying is performed by blowing air, but drying may also be performed without blowing air.

[0034] A water-soluble first polymer 141 is adhered in the form of a layer to the surfaces of anode body 8 and cathode body 9 of capacitor element 3 formed by immersing in solution 14 and drying. First polymer 141 also adheres to the surfaces of separator 7 and second polymer 142.

[0035] The second polymer 142 is granular. A plurality of granular second polymers 142 adhere to the surface of the anode body 8 to which the first polymer 141 is adhered and to the surface of the cathode body 9 to which the first polymer 141 is adhered. The second polymer 142 also adheres to the separator 7 to which the first polymer 141 is adhered. As a result, the plurality of granular second polymers 142 are arranged in a bridging manner between the surface of the anode body 8 and the surface of the separator 7 and between the surface of the cathode body 9 and the surface of the separator 7. In this way, the second polymer 142 electrically connects the anode body 8 and the cathode body 9.

[0036] Next, we will explain the room-temperature solid substance 2 disposed inside the case 1 of the solid electrolytic capacitor A. The room-temperature solid substance 2 is solid at a first temperature (e.g., 30°C) or lower, and is formed by dissolving an electrolyte in a solvent that melts when heated to a second temperature (melting point) that exceeds the first temperature.

[0037] At least one of polyethylene glycol, polyhydric alcohol, glycerin fatty acid ester, and sugar is used as the solvent contained in the room temperature solid substance 2. Examples of the solvent having a first temperature of 30°C and a second temperature of 50°C include polyethylene glycol, polyhydric alcohol, glycerin fatty acid ester, and sugar. Examples of the solvent having a first temperature of 30°C and a second temperature of 100°C include sugar.

[0038] Examples of polyethylene glycols that can be used with a first temperature of 30°C and a second temperature of 50°C include PEG2000 (melting point 51°C), PEG4000 (melting point 56°C), PEG6000 (melting point 58°C), PEG10000 (melting point 62°C), and PEG20000 (melting point 63°C). Here, PEG2000 refers to polyethylene glycol with an average molecular weight of 2000. The same applies to PEG4000, PEG6000, PEG10000, and PEG20000.

[0039] Examples of polyhydric alcohols having a first temperature of 30°C and a second temperature of 50°C include at least one of 1,2-dodecanediol (melting point 56 to 60°C) and 1,12-dodecanediol (melting point 79 to 81°C).

[0040] Examples of glycerin fatty acid esters having a first temperature of 30°C and a second temperature of 50°C include polyglyceryl-6 stearate (melting point 60 to 70°C), polyglyceryl-6 tristearate (melting point 50 to 60°C), polyglyceryl-4 pentastearate (melting point 50 to 60°C), polyglyceryl-10 decastearate (melting point 50 to 60°C), and polyglyceryl-10 hepta(behenate / stearate) (melting point 70 to 80°C).

[0041] Examples of sugars having a first temperature of 30°C and a second temperature of 50°C include xylitol (melting point 92°C) and sorbitol (melting point 95°C).

[0042] Examples of sugars having a first temperature of 30°C and a second temperature of 100°C include erythritol (melting point 121°C), lactitol (melting point 146°C), and glucose (melting point 150°C).

[0043] Furthermore, an acid or a base can be used as the electrolyte contained in the room-temperature solid substance 2. Examples of acids that are electrolytes contained in the room-temperature solid substance 2 include malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, decanedicarboxylic acid, tartronic acid, fumaric acid, maleic acid, citraconic acid, malic acid, tartaric acid, phthalic acid, nitrophthalic acid, citric acid, tricarbanilic acid, pyromellitic acid, boric acid, phosphoric acid, borodisalicylic acid, borodiglycolic acid, trinitrophenol, hydroxynitrophenol, hydroxynitrobenzoic acid, and sulfosalicylic acid.

[0044] Examples of the base that is an electrolyte contained in the room temperature solid substance 2 include ammonia, monoethylamine, diethylamine, triethylamine, trimethylamine, N,N-dimethylethylamine, N,N-diethylmethylamine, monoethanolamine, diethanolamine, triethanolamine, benzylamine, naphthylamine, morpholine, aniline, acetanilide, phenanthroline, caffeine, and imidazole.

[0045] Here, a method for producing the room-temperature solid substance 2 will be described with reference to Figs. 6 to 8. Fig. 6 is a diagram showing a melting step in which the room-temperature solid substance 2 is heated and melted. Fig. 7 is a diagram showing a solidification step in which the room-temperature solid substance 2 is solidified by cooling. Fig. 8 is a diagram showing a pulverization step in which the solidified room-temperature solid substance 2 is pulverized.

[0046] As shown in FIG. 6, a solvent 21 is placed in a container 15, and the container 15 is heated to a temperature equal to or higher than the melting point. As mentioned above, the melting point varies depending on the solvent. Then, an electrolyte 22 is poured into the liquefied solvent 21. A solution in which the electrolyte 22 is uniformly dissolved in the solvent 21 is produced (melting step). In FIG. 6, the lower part of the container 15 is heated to show the heating state, but this is not limiting. In the melting step, the container 15 may be heated using a heater or a high-frequency heating device.

[0047] Then, the heating of the container 15 is stopped, and the solution is cooled to a first temperature (for example, 30° C. (room temperature) in this case) to solidify (solidification step: see FIG. 7). As a result, a room-temperature solid substance 2 is produced. In the room-temperature solid substance 2, the electrolyte 22 is dispersed and disposed inside the solidified solvent 21.

[0048] 8, the room-temperature solid substance 2 solidified in the solidification step is pulverized (pulverization step). The room-temperature solid substance 2 is converted into powder by the pulverization step. In this way, powder 20 of the room-temperature solid substance is produced through the melting step, solidification step, and pulverization step.

[0049] Next, the procedure for housing the capacitor element 3 and the room-temperature solid substance 2 in the case 1 will be described with reference to FIGS. 9 to 15. FIG. 9 is a perspective view of a heating jig 16. FIG. 10 is a cross-sectional view of the case 1 housing powder 20 of a room-temperature solid substance therein. FIG. 11 is a cross-sectional view of the case 1 housing a liquid room-temperature solid substance 2. FIG. 12 is a cross-sectional view showing the state in which the capacitor element 3 is housed in the case 1 housing the liquid room-temperature solid substance 2. FIG. 13 is a cross-sectional view of the case 1 housing the solidified room-temperature solid substance 2 and the capacitor element 3 therein. FIG. 14 is a cross-sectional view showing the step of attaching a sealing body 4 to the case 1. FIG. 15 is a cross-sectional view of the case 1 with the sealing body 4 attached and a recess 5 formed therein.

[0050] In the manufacturing process of solid electrolytic capacitor A, powder 20 of a room temperature solid material is placed in case 1, and case 1 is heated to a second temperature or higher to melt room temperature solid material 2, after which capacitor element 3 is inserted into case 1 and then cooled.

[0051] In this manufacturing process, a heating jig 16 is used to hold the case 1 and heat the case 1. The heating jig 16 is made of a material with high rigidity and thermal conductivity, such as steel or brass. The heating jig 16 shown in FIG. 9 is a rectangular parallelepiped member. A plurality of recessed holes 161, five in this example, are provided on the top surface of the heating jig 16.

[0052] The recessed hole 161 has a shape that can accommodate the case 1, and is cylindrical in this example. The heating jig 16 heats the case 1 accommodated in the recessed hole 161. The heating method of the heating jig 16 can include, but is not limited to, electrical heating methods such as heating using electrical resistance and high-frequency induction heating. For example, the heating jig 16 accommodating the case 1, in which the room-temperature solid material powder 20 is accommodated in the recessed hole 161, may be placed in a high-temperature atmosphere such as an oven to heat the case 1 and the room-temperature solid material 2.

[0053] 10, powder 20 of a room-temperature solid substance is contained in case 1 housed in recess 161 of heating jig 16. By forming room-temperature solid substance 2 into powder in a pulverization process, it is easy to house room-temperature solid substance 2 inside case 1 at room temperature.

[0054] Then, the case 1 is heated via the heating jig 16 to raise the temperature of the room-temperature solid substance 2 to the second temperature, thereby melting the room-temperature solid substance 2 (re-melting step). As a result, the room-temperature solid substance 2 inside the case 1 is liquefied, as shown in FIG.

[0055] 12 , capacitor element 3 is inserted into case 1 containing liquid room-temperature solid material 2, with anode lead terminal 10 and cathode lead terminal 11 facing up (insertion step). Liquid room-temperature solid material 2 penetrates into capacitor element 3 by capillary action. As a result, liquid room-temperature solid material 2 is provided between the surfaces of anode body 8 and cathode body 9, on the surface of separator 7, and between the inner surface of case 1 and separator 7 on the outer periphery of capacitor element 3 (re-solidification step).

[0056] Thereafter, heating of case 1 by heating jig 16 is stopped, and case 1 is cooled. When the temperature of room-temperature solid substance 2 inside case 1 drops to a first temperature (room temperature: 30°C here) or lower due to cooling, a solid room-temperature solid substance 2 is disposed inside case 1. At this time, room-temperature solid substance 2 that is solid at a temperature equal to or lower than the first temperature (room temperature: 30°C) and that liquefies when heated to a second temperature higher than the first temperature is disposed between the surfaces of anode body 8 and cathode body 9, the surface of separator 7, and between the inner surface of case 1 and separator 7 on the outer periphery of capacitor element 3.

[0057] After being sufficiently cooled, the case 1 is removed from the heating jig 16. Then, a sealing body 4 is attached to the opening 1c of the case 1 (sealing step: see FIG. 14). The sealing body 4 has through holes 4a and 4b. The anode lead terminal 10 passes through the through hole 4a, and the cathode lead terminal 11 passes through the through hole 4b. This seals the opening 1c of the case 1. When the anode lead terminal 10 and the cathode lead terminal 11 pass through the through holes 4a and 4b, they come into close contact with the sealing body 4, so as to maintain an airtight seal inside.

[0058] As shown in Figure 15, with the sealing member 4 placed in the opening 1c of the case 1, the peripheral surface of the case 1 is drawn to form a recess 5. The open end of the case 1 is then bent inward to form a contact portion 6, which comes into contact with the sealing member 4. This prevents the sealing member 4 from shifting from the case 1. Through the above manufacturing procedure, solid electrolytic capacitor A is completed.

[0059] In the solid electrolytic capacitor A according to this embodiment, a first polymer 141 is attached to the surface of the anode body 8 of the capacitor element 3. The first polymer 141 is also attached to the surface of the cathode body 9 of the capacitor element 3. A second polymer 142 is disposed between the surface of the anode body 8 to which the first polymer is attached and the surface of the cathode body 9, so as to electrically connect the surface of the anode body 8 and the surface of the cathode body 9. Therefore, in the solid electrolytic capacitor A, the anode and the cathode are electrically connected without using an electrolyte. This allows the ESR of the solid electrolytic capacitor A to be maintained at a low level. Furthermore, in the solid electrolytic capacitor A according to this embodiment, no electrolyte is sealed in the case 1, which prevents deterioration of the capacitor characteristics due to evaporation of the electrolyte. This means that the capacitor characteristics of the solid electrolytic capacitor A can be maintained for a long period of time.

[0060] Furthermore, if cracks or peeling occur in the oxide film on the surface of the anode body 8 during use of the solid electrolytic capacitor A, leakage current will occur in that area, causing the temperature of the area through which the leakage current flows to rise. This temperature rise will cause the solvent 21 in the room-temperature solid material 2 to liquefy. The oxide film will then be repaired by the electrolyte 22 contained in the room-temperature solid material 2. Once the oxide film is repaired, leakage current will be suppressed. This will cause the ambient temperature to drop, and the room-temperature solid material 2 will return to a solid state. This also makes it possible to prevent deterioration of the capacitor characteristics of the solid electrolytic capacitor A over a long period of time.

[0061] Furthermore, a room-temperature solid material 2 is disposed between the inner surface of the case 1 and the outer surface of the capacitor element 3. Therefore, the capacitor element 3 is held to the inner surface of the case 1 by the room-temperature solid material 2. As a result, external forces such as shocks or vibrations acting on the solid electrolytic capacitor A are less likely to be transmitted to the capacitor element 3, and deterioration of the capacitor element 3 due to external forces is suppressed. This makes it possible to suppress deterioration of the capacitor characteristics of the solid electrolytic capacitor A over a long period of time.

[0062] Note that the solid electrolytic capacitor A may be used in a high-temperature environment. In this case, the temperature inside the case 1 of the solid electrolytic capacitor A may reach or exceed the second temperature (the melting point of the solvent 21). In this case, the room-temperature-solid substance 2 melts and liquefies. The liquefied room-temperature-solid substance 2 has a higher viscosity than conventional electrolytic solutions. Therefore, even if the room-temperature-solid substance 2 inside the case 1 liquefies due to a temperature rise, external forces such as vibration and impact can be prevented from being transmitted to the capacitor element 3. In other words, external forces such as impact and vibration acting on the solid electrolytic capacitor A are less likely to be transmitted to the capacitor element 3, and deterioration of the capacitor element 3 due to external forces is suppressed. This prevents deterioration of the capacitor characteristics of the solid electrolytic capacitor A over a long period of time.

[0063] For example, PEG6000 (melting point 58°C) will be described as the solvent 21 of the room-temperature solid substance 2. The kinetic viscosity of PEG6000 at 80°C is approximately 1000 mm2 / s, which is approximately 1000 times the kinetic viscosity (approximately 1 mm2 / s) of water (a component of the electrolyte) at 80°C. Therefore, even if the temperature inside the case 1 reaches or exceeds the second temperature in the usage environment of the solid electrolytic capacitor A, the lead terminals of the capacitor element 3 are unlikely to break due to vibration caused by an external force.

[0064] FIG. 16 is a diagram showing the aging treatment. Aging treatment is performed on a capacitor to stabilize its characteristics. The aging treatment is described below. As shown in FIG. 16, solid electrolytic capacitor A is held with the anode lead terminal 10 and the cathode lead terminal 11 facing downward. Then, solid electrolytic capacitor A is heated to a temperature equal to or higher than the second temperature at which the solvent 21 of the room temperature solid substance 2 melts. In this state, a predetermined voltage is applied to the anode lead terminal 10 and the cathode lead terminal 11 for a predetermined time.

[0065] During such an aging treatment, when the temperature of room-temperature solid substance 2 of solid electrolytic capacitor A reaches the second temperature, solvent 21 of room-temperature solid substance 2 melts and flows down toward sealing member 4. After the aging treatment, solid electrolytic capacitor A is cooled, and the temperature of room-temperature solid substance 2 falls to the first temperature (room temperature) or lower, and room-temperature solid substance 2 solidifies near sealing member 4 (see FIG. 16).

[0066] That is, immediately after solid electrolytic capacitor A is manufactured, that is, before aging treatment, room-temperature solid material 2 is located on the bottom 1a side of case 1, as shown in FIG. 1. Then, after aging treatment, room-temperature solid material 2 moves to the sealing body 4 side of case 1. At this time, the outer surface of capacitor element 3 is held to the inner surface of case 1 by room-temperature solid material 2. As a result, external forces such as shocks and vibrations are less likely to be transmitted to capacitor element 3, and deterioration of capacitor element 3 due to external forces is suppressed. This makes it possible to suppress deterioration of the capacitor characteristics of solid electrolytic capacitor A over a long period of time.

[0067] As described above, the room-temperature solid substance 2 has penetrated the interior of the capacitor element 3. The aging treatment melts the room-temperature solid substance 2 that has penetrated the interior of the capacitor element 3, and the room-temperature solid substance 2 is liquefied. The liquefied room-temperature solid substance 2 is held inside the capacitor element 3 by capillary action due to the separator 7, anode body 8, and cathode body 9 that constitute the capacitor element 3, and is prevented from leaking out of the capacitor element 3. This makes it difficult for the oxide film on the anode body 8 to be repaired. In other words, in solid electrolytic capacitor A, degradation of the capacitor characteristics is prevented over a long period of time, regardless of whether the aging treatment is performed.

[0068] Fig. 17 is a diagram showing a solid electrolytic capacitor A1 according to another embodiment of the present invention. As in the solid electrolytic capacitor A1 shown in Fig. 17, instead of the rubber sealing member 4, a resin sealing member 40 may be formed by pouring resin into the opening 1c of the case 1. Because no electrolyte is contained in the case 1, the opening 1c of the case 1 can be adequately sealed with the resin sealing member 40.

[0069] <Example> Specific examples (Examples 1 to 4) of the solid electrolytic capacitor A having the above-described configuration will be described.

[0070] Example 1 First, as shown in FIG. 6, PEG10000 (melting point 62°C) is placed in a container 15 as a solvent 21. Then, the solvent 21 is heated to 80°C, which is above the melting point of the solvent 21, and then trimethylamine borodisalicylate is added as an electrolyte 22 to the melted and liquid solvent 21, and the mixture is stirred to dissolve the electrolyte 22 uniformly in the solvent 21, thereby producing a liquid substance 2 that is solid at room temperature. The substance 2 that is solid at room temperature is a solution with a 15% concentration of the electrolyte 22. In other words, an amount of electrolyte 22 sufficient to achieve a 15% concentration in the liquid substance 2 that is solid at room temperature is added to the solvent 21.

[0071] 7, heating of the container 15 is stopped and the container is cooled to room temperature (e.g., 30°C) or below to form a solid state room temperature solid substance 2. Next, as shown in FIG. 8, the room temperature solid substance 2 in the container 15 is pulverized to produce a powder 20 of the room temperature solid substance.

[0072] Capacitor element 3 was fabricated using the following procedure. First, separator 7, anode body 8, and cathode body 9 were stacked. Then, the anode body 8 was rolled up with the anode body 8 facing inward, and the outer separator 7 was secured with tape 12 to create molded capacitor 31. Then, molded capacitor 31 was immersed in an aqueous solution of ammonium adipate in a chemical conversion solution layer, and a voltage of 60 V was applied between anode lead terminal 10 and the chemical conversion solution for 15 minutes. This repaired the oxide film on the surface of anode body 8, and then it was dried at 125°C for 30 minutes. In this state, molded capacitor 31 had a capacity of 35 V-270 μF as a capacitor.

[0073] The molded capacitor body 31 was then immersed in a polymer solution prepared by mixing 25 parts of a self-doping conductive polymer aqueous solution (SELFTRON manufactured by Tosoh Corporation) as the first polymer 141 and 75 parts of a thiophene-based conductive polymer aqueous dispersion (manufactured by Heraeus K.K.) as a substance containing the second polymer 142. The molded capacitor body 31 was then removed from the polymer solution and dried for 30 minutes in an atmosphere at 125°C. This produced a capacitor element 3 in which the first polymer 141 and the second polymer 142 were attached to the surfaces of the separator 7, the anode body 8, and the cathode body 9. A first and a second polymer were formed.

[0074] Thereafter, 120 mg of powder 20 of the room-temperature solid material is placed inside case 1, which has a diameter of 10 mm and a height of 10.5 mm. Then, case 1 containing powder 20 of the room-temperature solid material is set in recess 161 of heating jig 16. Then, case 1 is heated to 80°C to melt room-temperature solid material 2 inside case 1. At this time, liquid room-temperature solid material 2 is contained in case 1.

[0075] Then, the capacitor element 3 is inserted through the opening 1c of the case 1. At this time, the capacitor element 3 is supported so that a portion of the capacitor element 3 is immersed in the liquid room-temperature solid material 2. Then, heating is stopped to lower the temperature, and the room-temperature solid material 2 inside the case 1 solidifies. Thereafter, the anode lead terminal 10 and the cathode lead terminal 11 are inserted into the through-holes 4a and 4b of the sealing body 4 made of butyl rubber. Then, the recess 5 and the abutment portion 6 are formed in the case 1, and the solid electrolytic capacitor A is completed.

[0076] Thereafter, the completed solid electrolytic capacitor A was held so that the anode lead terminal 10 and the cathode lead terminal 11 faced downwards. In this state, the capacitor was placed in an atmosphere at approximately 125°C, and a predetermined voltage was applied to the anode lead terminal 10 and the cathode lead terminal 11 for one hour for aging treatment, thereby producing a solid electrolytic capacitor A1 of Example 1.

[0077] Even in the solid electrolytic capacitor A manufactured in this manner, the room-temperature solid material 2 is interposed between the inner surface of the case 1 and the outer surface of the capacitor element 3, so that the capacitor element 3 is securely held in the case 1. Furthermore, the room-temperature solid material 2 is interposed between the case 1 and the capacitor element 3, so that the transmission of external forces due to shocks, vibrations, etc. applied to the case 1 to the capacitor element 3 is suppressed. This suppresses deterioration of the capacitor element 3 due to external forces.

[0078] An experiment was also conducted to confirm the ability to repair the oxide film on the surface of anode body 8 of solid electrolytic capacitor A of Example 1. Figure 18 is a graph showing the results of an experiment to confirm the ability to repair the oxide film in solid electrolytic capacitor A of Example 1.

[0079] First, the experimental method and details will be described. As described above, in solid electrolytic capacitor A, when the oxide film on the surface of anode body 8 is damaged, leakage current LC is generated concentrating from the damaged portion of the oxide film. In other words, a large leakage current LC is generated. After a certain period of time has passed while the leakage current is flowing, the temperature near the damaged portion of the oxide film rises, and room-temperature solid material 2 is heated and changes to a liquid state. Then, the oxide film is repaired by electrolyte 22 of liquid room-temperature solid material 2. As the repair of the oxide film progresses, the leakage current LC decreases.

[0080] Based on the occurrence of this phenomenon, the leakage current of solid electrolytic capacitor A can be detected, and based on the change in leakage current LC, the repair of the oxide film on the surface of anode body 8 can be confirmed. Therefore, in this experiment, the leakage current was detected while a predetermined voltage was applied, and the change in leakage current due to the repair of the oxide film was confirmed.

[0081] In this experiment, a solid electrolytic capacitor A was prepared in which the oxide film on the end of the anode body 8 of the capacitor element 3 had not been repaired, i.e., the anode body 8 was exposed. A voltage of 25 V was applied between the anode lead terminal 10 and the cathode lead terminal 11 at room temperature. The leakage current LC was measured while maintaining the applied voltage. The repair of the oxide film on the anode body 8 was determined based on the change in the leakage current LC.

[0082] In the graph of Figure 18, the vertical axis represents leakage current LC (μA). The horizontal axis represents the elapsed time from the start of the experiment. Note that the vertical axis of the graph shown in Figure 18 is a logarithmic axis. It can be seen that a large leakage current LC (approximately 70,000 μA in Figure 18) flows at the start of the experiment. This large leakage current LC continues to flow for approximately 30 seconds. Then, approximately 30 seconds after the start of the experiment, the leakage current decreases rapidly and converges to a constant current amount as time passes.

[0083] To explain this, immediately after the start of the experiment, a portion of the anode body 8 is exposed, and therefore leakage current LC is generated concentrating on the exposed portion of the anode body 8. Therefore, a large leakage current LC flows immediately after the start of the experiment. Immediately after the start of the experiment, the anode body 8 is heated by Joule heat due to this large leakage current LC. Then, as the temperature of the anode body 8 rises, the temperature of the room-temperature solid material 2 also rises. Thereafter, when the temperature of the room-temperature solid material 2 rises to the second temperature, the solvent 21 of the room-temperature solid material 2 melts and changes into the liquid room-temperature solid material 2. It is thought that the time from the start of the experiment until the room-temperature solid material 2 melts and changes into the liquid room-temperature solid material 2 is approximately 30 seconds.

[0084] The oxide film on the surface of anode body 8 is repaired by electrolyte 22 contained in liquid room-temperature solid material 2. When the oxide film on the surface of anode body 8 is repaired, the exposed area of anode body 8 becomes smaller, and the leakage current decreases. In other words, it is thought that the oxide film on the surface of anode body 8 begins to be repaired by electrolyte 22 in liquid room-temperature solid material 2 approximately 30 seconds after the start of the experiment.

[0085] As time passes, that is, as the repair progresses, the leakage current LC decreases. The decrease in leakage current LC causes the temperature of anode body 8 to decrease, and the temperature of room-temperature solid material 2 to also decrease. As time passes, the leakage current LC decreases, and the amount of heat generated by anode body 8 decreases. This also cools room-temperature solid material 2, and when room-temperature solid material 2 cools to or below the first temperature, it solidifies. As the oxide film is repaired and room-temperature solid material 2 solidifies, the leakage current LC is kept low.

[0086] As described above, in solid electrolytic capacitor A, even if the oxide film of anode body 8 is damaged and anode body 8 is exposed, it is found that the oxide film is repaired by electrolyte 22 contained in room-temperature solid material 2. As a result, in solid electrolytic capacitor A, deterioration of the capacitor characteristics is suppressed for a long period of time.

[0087] Example 2 In Example 2, polyglyceryl-4 pentastearate (melting point: 50°C to 60°C) was used as solvent 21 for room-temperature solid substance 2. Solvent 21 was heated to 100°C, which is above the melting point of solvent 21. Trimethylamine borodisalicylate was then added as electrolyte 22 to melted and liquid solvent 21, and the mixture was stirred to dissolve electrolyte 22 uniformly in solvent 21, thereby producing liquid room-temperature solid substance 2. Room-temperature solid substance 2 was a solution with a 15% electrolyte 22 concentration. In other words, an amount of electrolyte 22 sufficient to achieve a 15% concentration in liquid room-temperature solid substance 2 was added to solvent 21. Other than that, the composition was the same as in Example 1. It was found that the solid electrolytic capacitor of Example 2 configured in this manner had the same effects as Example 1.

[0088] Example 3 In Example 3, sorbitol (melting point 95°C) was used as solvent 21 for room-temperature solid substance 2. Solvent 21 was then heated to 115°C, which is above the melting point of solvent 21. Then, trimethylamine borodisalicylate was added as electrolyte 22 to melted and liquid solvent 21, and the mixture was stirred to dissolve electrolyte 22 uniformly in solvent 21, thereby producing liquid room-temperature solid substance 2. Room-temperature solid substance 2 was a solution with a 15% electrolyte 22 concentration. That is, an amount of electrolyte 22 sufficient to achieve a 15% concentration in liquid room-temperature solid substance 2 was added to solvent 21. Other than that, the solid substance was configured similarly to Example 1. It was found that the solid electrolytic capacitor of Example 2 configured in this manner had the same effects as Example 1.

[0089] Example 4 In Example 4, glucose (melting point 150°C) was used as solvent 21 for room-temperature solid substance 2. Solvent 21 was then heated to 170°C, which is above the melting point of solvent 21. After that, trimethylamine borodisalicylate was added as electrolyte 22 to melted and liquid solvent 21, and the mixture was stirred to dissolve electrolyte 22 uniformly in solvent 21, thereby producing liquid room-temperature solid substance 2. Room-temperature solid substance 2 was a solution with a 15% electrolyte 22 concentration. That is, an amount of electrolyte 22 sufficient to achieve a 15% concentration in liquid room-temperature solid substance 2 was added to solvent 21. Other than that, the solid substance was configured similarly to Example 1. It was found that the solid electrolytic capacitor of Example 2 configured in this manner had the same effects as Example 1.

[0090] In the above-described embodiment, capacitor element 3 is manufactured by the following manufacturing method (referred to as a first manufacturing method here). First polymer 141 and water-dispersible second polymer 142 are formed on molded capacitor body 31 by immersing 14 in a solution in which first polymer 141 and second polymer 142 have been stirred, and then capacitor element 3 is formed by lifting molded capacitor body 31 out of solution 14 and drying for 30 minutes in an atmosphere at 125°C. This manufacturing method for capacitor element 3 is referred to as a first manufacturing method.

[0091] As another method for manufacturing the capacitor element 3, a second manufacturing method different from the first manufacturing method can also be adopted. That is, in the second manufacturing method, the molded capacitor body 31 is immersed in a solution 14 containing a first polymer 141. Thereafter, the molded capacitor body 31 is removed from the solution 14 and dried for 30 minutes in an atmosphere at 125°C. Next, the dried molded capacitor body 31 is immersed in a solution 14 containing a second polymer 142. Thereafter, the capacitor element 3 is removed from the solution 14 and dried for 30 minutes in an atmosphere at 125°C. With this configuration, the manufacturing process becomes two-stage, but the first polymer 141 and the second polymer 142 can be formed on the capacitor element 3 by the second manufacturing method as well.

[0092] Furthermore, as another method for manufacturing the capacitor element 3, a third manufacturing method different from the first and second manufacturing methods can also be adopted. That is, in the third manufacturing method, the molded capacitor body 31 is immersed in a solution 14 containing a second polymer 142. Thereafter, the molded capacitor body 31 is removed from the solution 14 and dried for 30 minutes in an atmosphere at 125°C. Next, the dried molded capacitor body 31 is immersed in a solution 14 containing a first polymer 141. Thereafter, the capacitor element 3 is removed from the solution 14 and dried for 30 minutes in an atmosphere at 125°C. With this configuration, the manufacturing process becomes two-stage, but the first polymer 141 and the second polymer 142 can also be formed on the capacitor element 3 by the second manufacturing method.

[0093] Even when using the capacitor element 3 formed by the three manufacturing methods described above, the typical characteristics (capacitance, tanδ, ESR) of the solid electrolytic capacitor A were all good. In the three manufacturing methods described above, the first polymer 141 was attached in layers to the surfaces of the anode body 8 and the cathode body 9 of the capacitor element 3. It was also found that the second polymer 142 was present between the surfaces of the anode body 8 and the cathode body 9 to which the first polymer 141 was attached in layers, electrically connecting the surfaces of the anode body 8 and the cathode body 9. As a result, the typical characteristics (capacitance, tanδ, ESR) of the solid electrolytic capacitor A all exhibited good conditions.

[0094] From the above, it can be seen that in capacitor element 3 of solid electrolytic capacitor A, first polymer 141 is in a state of being attached in the form of a layer to the surfaces of anode body 8 and cathode body 9 of capacitor element 3. It is also understood that it is important that second polymer 142 exists between the surface of anode body 8 and the surface of cathode body 9 to which first polymer 141 is attached in the form of a layer, in a state of electrically connecting the surface of anode body 8 and the surface of cathode body 9. [Explanation of symbols]

[0095] A Solid electrolytic capacitor A1 Solid electrolytic capacitor 1 case 1a bottom 1b Cylinder part 1c opening 2 Solid substances at room temperature 20 Powder of solid substance at room temperature 21 Solvent 22 Electrolytes 3 Capacitor elements 31 Molded capacitor 4 Sealing body 4a, 4b through hole 40 Sealing body 5 recess 6 Contact part 7 Separator 8 Anode body 9 Cathode body 10 Anode lead terminal 11 Cathode lead terminal 12 Tape 13 Container 14 solution 141 First Polymer 142 Second Polymer 15 Container 16 Heating jig 161 Hole

Claims

1. a cylindrical case with a bottom and an opening; a capacitor element formed by winding an anode body and a cathode body with a separator interposed therebetween and housed in the case; a sealing body that seals the opening, The capacitor element is a water-soluble first polymer disposed on a surface of the anode body and a surface of the cathode body; a water-dispersible second polymer disposed on the surface of the anode body on which the first polymer is provided and on the surface of the cathode body on which the first polymer is provided, the second polymer electrically connects a surface of the anode body and a surface of the cathode body; a solid electrolytic capacitor in which a room-temperature solid material, in which an electrolyte is dissolved in a solvent that is solid at or below a first temperature and melts when heated to or above a second temperature that is higher than the first temperature, is disposed between the surface of the anode body and the surface of the cathode body of the capacitor element, and between the inner surface of the case and the outer surface of the capacitor element;

2. The solid electrolytic capacitor according to claim 1 , wherein the first polymer is provided on a surface of the anode body, a surface of the cathode body, and a surface of the separator.

3. 3. The solid electrolytic capacitor according to claim 1, wherein the first temperature is 30°C.

4. 4. The solid electrolytic capacitor according to claim 3, wherein the solvent contains at least one of polyethylene glycol, polyhydric alcohol, glycerin fatty acid ester, and sugar.

5. The solid electrolytic capacitor according to claim 3 , wherein the second temperature of the solvent is 50° C.

6. The solvent is 6. The solid electrolytic capacitor according to claim 5, comprising at least one of PEG2000, PEG4000, PEG6000, PEG10000, PEG20000, 1.2-dodecanediol, 1.12-dodecanediol, polyglyceryl-6 stearate, polyglyceryl-6 tristearate, polyglyceryl-4 pentastearate, polyglyceryl-10 decastearate, polyglyceryl-10 hepta(behenate / stearate), xylitol, and sorbitol.

7. The solid electrolytic capacitor according to claim 3 , wherein the second temperature of the solvent is 100° C.

8. 8. The solid electrolytic capacitor according to claim 7, wherein the solvent contains at least one of erythritol, lactitol, and glucose.

9. The electrolyte is At least one of the following acids is included: malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, decanedicarboxylic acid, tartronic acid, fumaric acid, maleic acid, citraconic acid, malic acid, tartaric acid, phthalic acid, nitrophthalic acid, citric acid, tricarbanilic acid, pyromellitic acid, boric acid, phosphoric acid, borodisalicylic acid, borodiglycolic acid, trinitrophenol, hydroxynitrophenol, hydroxynitrobenzoic acid, and sulfosalicylic acid; Or, 9. The solid electrolytic capacitor according to claim 1, further comprising at least one base selected from the group consisting of ammonia, monoethylamine, diethylamine, triethylamine, trimethylamine, N,N-dimethylethylamine, N,N-diethylmethylamine, monoethanolamine, diethanolamine, triethanolamine, benzylamine, naphthylamine, morpholine, aniline, acetanilide, phenanthroline, caffeine, and imidazole.

10. 10. The solid electrolytic capacitor according to claim 1, wherein the sealing member is made of rubber or resin.

11. A method for manufacturing a solid electrolytic capacitor including: a capacitor element to be housed in a case; and a room-temperature solid substance, which is solid at or below a first temperature and is formed by dissolving an electrolyte in a solvent that is solid at or below a first temperature and melts when heated to or above a second temperature that is higher than the first temperature, and a sealing body that seals an opening of the case, a capacitor element manufacturing process in which a capacitor molded body formed by winding an anode body and a cathode body with a separator interposed therebetween is immersed in a solution containing a water-soluble first polymer and a water-dispersible second polymer, and the capacitor molded body is pulled out of the solution and dried, thereby manufacturing the capacitor element; and an insertion step of inserting the capacitor element into the case containing the room-temperature solid material that has been heated to or above the second temperature and melted, and allowing a portion of the melted room-temperature solid material to penetrate into the capacitor element.

12. A method for manufacturing a solid electrolytic capacitor including: a capacitor element to be housed in a case; and a room-temperature solid substance, which is solid at or below a first temperature and is formed by dissolving an electrolyte in a solvent that is solid at or below a first temperature and melts when heated to or above a second temperature that is higher than the first temperature, and a sealing body that seals an opening of the case, a capacitor element manufacturing process for manufacturing the capacitor element by carrying out the steps of: immersing a molded capacitor body formed by winding an anode body and a cathode body with a separator interposed therebetween in a solution containing a water-soluble first polymer; removing the molded capacitor body from the solution and drying it; immersing the dried molded capacitor body in a solution containing a water-dispersible second polymer; and removing the molded capacitor body from the solution and drying it; and an insertion step of inserting the capacitor element into the case containing the room-temperature solid material that has been heated to or above the second temperature and melted, and allowing a portion of the melted room-temperature solid material to penetrate into the capacitor element.

13. A method for manufacturing a solid electrolytic capacitor including: a capacitor element to be housed in a case; and a room-temperature solid substance, which is solid at or below a first temperature and is formed by dissolving an electrolyte in a solvent that is solid at or below a first temperature and melts when heated to or above a second temperature that is higher than the first temperature, and a sealing body that seals an opening of the case, a capacitor element manufacturing process for manufacturing the capacitor element by carrying out the steps of: immersing a molded capacitor body formed by winding an anode body and a cathode body with a separator interposed therebetween in a solution containing a water-dispersible second polymer; removing the molded capacitor body from the solution and drying it; immersing the dried molded capacitor body in a solution containing a water-soluble first polymer; and removing the molded capacitor body from the solution and drying it; and an insertion step of inserting the capacitor element into the case containing the room-temperature solid material that has been heated to or above the second temperature and melted, and allowing a portion of the melted room-temperature solid material to penetrate into the capacitor element.

14. a crushing step of crushing the solid room temperature solid substance into powder; a re-melting step of heating the room-temperature solid substance together with the case after the powder room-temperature solid substance is poured into the case to melt the room-temperature solid substance, 14. The method for manufacturing a solid electrolytic capacitor according to claim 11, wherein the crushing step and the remelting step are performed before the inserting step.

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