Capacitor

Abstract

To provide a capacitor that can improve moisture resistance with a long life.SOLUTION: A capacitor 1 includes: a capacitor element 3 which holds a predetermined liquid formulation between a pair of electrodes 5 and 7 opposed to each other via a separator 6; a body case 2 which houses the capacitor element 3; and a rubber-made sealing body 4 which seals the body case 2. The capacitor has a supply part that supplies a liquid formulation held in the capacitor element 3 while being in contact with the sealing body 4 to the sealing body 4. The liquid formulation is obtained by dissolving a lipid-soluble sealing body degradation inhibitor in a lipophilic solvent. The sealing body degradation inhibitor supplied to the sealing body 4 by the supply part penetrates into the sealing body 4. The weight ratio of the sealing body degradation inhibitor in the sealing body 4 with respect to the sealing body 4 is between 0.1 wt.% and 25 wt.%.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a capacitor sealed with a sealing body. [Background technology]

[0002] A conventional capacitor is disclosed in Patent Document 1. This capacitor includes a main case, a capacitor element, and a sealing body. The main case is made of metal and has a bottomed, cylindrical shape with one end closed and the other end having an opening.

[0003] The capacitor element is made by winding an anode foil and a cathode foil on which an oxide film has been formed, with a separator between them, and storing them in a main case. A conductive polymer and an electrolyte are held between the anode foil and the cathode foil. The electrolyte contains a specified non-volatile solvent. The opening of the main case storing the capacitor element is sealed with a rubber seal.

[0004] In the above capacitor, since the electrolyte contains a low-volatility solvent, evaporation of the electrolyte solvent in a high-temperature environment such as an engine compartment can be suppressed, and the ESR can be reduced from low to high temperature environments.

[0005] Furthermore, the capacitor of Patent Document 2 holds a hydrophilic polymer between the anode foil and the cathode foil. The hydrophilic polymer holds moisture, and the moisture can repair defects in the oxide film formed on the anode foil. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2017-228738 A (pages 4-9, Figure 1) [Patent Document 2] International Publication No. 2014 / 050913 (pages 9-23, Figure 2) [Patent Document 3] JP 2000-100670 A (pages 2-4, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0007] However, when the capacitor disclosed in Patent Document 1 is used in a high-temperature environment such as 150°C, fine cracks may occur in the rubber seal due to deterioration. The fine cracks in the seal cause further cracks to spread due to stress concentration, etc., and the thickness of the rubber effective as a seal becomes thinner. A seal with a thin effective rubber thickness increases the amount of moisture permeating, deteriorating the characteristics of the capacitor. This causes a problem of low moisture resistance of the capacitor.

[0008] In addition, when polymers such as rubber are exposed to heat or light energy in the presence of oxygen, such as in the air, it is said that a chain reaction of oxidation occurs due to the generation of radicals, resulting in a deterioration of physical properties. For this reason, Patent Document 3 describes the incorporation of an antioxidant (antiaging agent) into the sealing body to suppress the oxidation reaction.

[0009] However, the antioxidant mixed into the sealant is consumed and gradually lost as it performs its antioxidant function. When a capacitor is used in a high-temperature environment, the sealant deteriorates rapidly as the antioxidant is lost, and the amount of moisture that permeates through the sealant increases. For this reason, there has been a demand for a capacitor that has a long life and is highly moisture-resistant, and that suppresses the deterioration of the sealant even when used in a high-temperature environment such as 150°C.

[0010] Similarly, in the capacitor disclosed in Patent Document 2, when the capacitor is used in a high temperature environment, the sealing member deteriorates, causing an increase in the amount of moisture permeating, thereby deteriorating the characteristics of the capacitor.

[0011] An object of the present invention is to provide a capacitor that has a long life and improved moisture resistance. [Means for solving the problem]

[0012] In order to achieve the above-mentioned object, the present invention provides a capacitor comprising a capacitor element holding a predetermined liquid agent between a pair of opposing electrodes sandwiching a separator therebetween, a main case that houses the capacitor element, and a rubber seal that seals the main case, wherein the liquid agent contains a sealant deterioration inhibitor, the sealant deterioration inhibitor is supplied from the capacitor element and permeates into the interior of the sealant, and the sealant has a thickness of 1.4 mm or more and 7 mm or less.

[0013] In the capacitor of the present invention having the above structure, the sealant deterioration inhibitor is a compound which is more easily oxidized than the components of the sealant.

[0014] Furthermore, the present invention is characterized in that in the capacitor having the above structure, the sealing body deterioration inhibitor has a molecular weight of 200 to 3,000.

[0015] Furthermore, the present invention is characterized in that in the capacitor having the above-mentioned structure, the liquid agent comprises an electrolytic solution in which the sealing body deterioration inhibitor and an electrolyte are dissolved in the lipophilic solvent.

[0016] Furthermore, the present invention is characterized in that in the capacitor having the above configuration, the electrolyte contains an organic amine salt, and the electrolytic solution contains a hydrophobic organic amine that forms the organic amine salt.

[0017] Furthermore, the present invention is characterized in that in the capacitor having the above configuration, the capacitor element holds a solid electrolyte made of a conductive polymer, and the conductive polymer contains a dopant having a sulfonic acid group.

[0018] Furthermore, the present invention is characterized in that in the capacitor having the above-mentioned configuration, the capacitor element holds a solid electrolyte made of a conductive polymer, and a dopant of the conductive polymer has a sulfonic acid group as a substituent.

[0019] Furthermore, the present invention is characterized in that in the capacitor having the above configuration, the capacitor element holds a solid electrolyte made of a conductive polymer, and the electrolytic solution contains a hydrolyzable ester compound.

[0020] Furthermore, the present invention is characterized in that in the capacitor having the above configuration, the hydrolyzable ester compound is a borate ester compound, and the concentration of the borate ester compound in the electrolyte is 0.1% by weight to 20% by weight.

[0021] Furthermore, the present invention is characterized in that in the capacitor having the above structure, the capacitor element holds a solid electrolyte made of a conductive polymer.

[0022] Furthermore, the present invention is characterized in that in the capacitor having the above configuration, the supply portion is formed by the separator.

[0023] Furthermore, in the capacitor of the present invention having the above configuration, a central portion of the surface of the sealing body facing the capacitor element protrudes beyond an outer periphery.

[0024] The present invention is also characterized in that, in the capacitor having the above-mentioned configuration, the main body case has a protrusion that protrudes from its inner surface and presses against the outer peripheral surface of the sealing body, and the apex of the protrusion is positioned away from the capacitor element relative to the center of the thickness direction of the sealing body.

[0025] Furthermore, the present invention is characterized in that in the capacitor having the above configuration, the supply portion connects the separator and the sealing body.

[0026] Furthermore, the present invention is characterized in that in the capacitor having the above structure, the sealant deterioration inhibitor is a fat-soluble vitamin.

[0027] Furthermore, the present invention is characterized in that in the capacitor having the above configuration, the fat-soluble vitamin is tocopherol or tocotrienol.

[0028] Furthermore, the present invention is characterized in that in the capacitor having the above structure, the lipophilic solvent is γ-butyrolactone.

[0029] Furthermore, the present invention is characterized in that in the capacitor having the above-mentioned configuration, the lipophilic solvent is any one of polyethylene glycol, glycerin, and polyglycerin to which a lipophilic group is bonded.

[0030] Furthermore, the present invention is characterized in that in the capacitor having the above-mentioned configuration, the liquid agent contains the lipophilic solvent, any one of sulfolane, ethylene glycol, diethylene glycol, and polyethylene glycol, and an amphipathic compound. Effect of the Invention

[0031] According to the present invention, the capacitor element holds a liquid agent in which a fat-soluble sealant deterioration inhibitor is dissolved in a lipophilic solvent, and the liquid agent supplied from the capacitor element by the supply unit permeates into the sealant. This makes it possible to suppress an increase in the amount of moisture permeation due to deterioration of the sealant for a long period of time. This makes it possible to provide a capacitor with a long life and high moisture resistance. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a perspective view of a capacitor according to a first embodiment of the present invention, as viewed from above; [Diagram 2] FIG. 1 is a perspective view of a capacitor according to a first embodiment of the present invention, as viewed from below; [Diagram 3] FIG. 1 is a front cross-sectional view showing a capacitor according to a first embodiment of the present invention. [Figure 4] FIG. 1 is a perspective view showing a capacitor element of a capacitor according to a first embodiment of the present invention; [Diagram 5] Detailed view of part H in Figure 3 [Figure 6] FIG. 5 is a front cross-sectional view showing a capacitor according to a second embodiment of the present invention. [Figure 7] Detailed view of part J in Fig. 6 [Figure 8] Detailed view of part K in Fig. 6 [Figure 9] FIG. 11 is a front cross-sectional view showing an element storage step of a capacitor according to a second embodiment of the present invention. [Figure 10] FIG. 11 is a plan view showing an element storage step of a capacitor according to a second embodiment of the present invention. [Figure 11] FIG. 11 is a front cross-sectional view showing a sealing body attachment process for a capacitor according to a second embodiment of the present invention. [Figure 12] FIG. 13 is a diagram showing the results of a high-temperature, high-humidity load test of the capacitor according to the third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] First Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figures 1 and 2 show a perspective view of a capacitor 1 of a first embodiment as seen from above and below. Capacitor 1 is an electrolytic capacitor, and is mounted on a seat plate 15. Seat plate 15 is made of synthetic resin and holds capacitor 1. Seat plate 15 is provided with a pair of through holes 15a, 15b.

[0034] Capacitor 1 has lead terminals 8, 9, and the lead terminals 8, 9 inserted into through holes 15a, 15b of base plate 15 are bent outward. As a result, capacitor 1 is placed on the circuit board while the top surface of main body case 2 is held by an automated machine, and the lead terminals 8, 9 are soldered to the lands of the circuit board for mounting.

[0035] 3 shows a front cross-sectional view of capacitor 1. Capacitor 1 comprises a main case 2, a capacitor element 3, and a sealing body 4. Main case 2 is made of a metal such as aluminum and is formed into a cylindrical shape with a circular cross section and a bottom, with one end closed by an end wall 2a and an opening 2b at the other end. Capacitor element 3 is housed in main case 2, and opening 2b is sealed by sealing body 4.

[0036] 4 shows a perspective view of capacitor element 3. Capacitor element 3 has anode foil 5, cathode foil 7, and separator 6, which are formed in a long strip shape. Capacitor element 3 is formed by rolling anode foil 5 and cathode foil 7 into a cylindrical shape with separator 6 interposed therebetween. In this way, anode foil 5 and cathode foil 7 form a pair of electrodes facing each other with separator 6 interposed therebetween.

[0037] The strip-shaped anode foil 5, cathode foil 7, and separator 6 are long and narrow in the winding direction (longitudinal direction), and the width in the direction perpendicular to the winding direction (transverse direction) is shorter than the length in the winding direction. The ends of the anode foil 5 or cathode foil 7 are fixed with tape 12. A lead terminal 8 is connected to the anode foil 5, and a lead terminal 9 is connected to the cathode foil 7.

[0038] The width of separator 6 in the short side direction (axial direction) is formed to be larger than the width of anode foil 5 and cathode foil 7 in the short side direction. As a result, separator 6 protrudes upward (toward end wall portion 2a) and downward (toward opening 2b) relative to anode foil 5 and cathode foil 7, preventing a short circuit between anode foil 5 and cathode foil 7.

[0039] The anode foil 5 and the cathode foil 7 are mainly made of aluminum, and their surfaces are expanded by etching. The anode foil 5 has a dielectric oxide film formed on its surface by chemical conversion. The cathode foil 7 may have a natural oxide film formed on its surface, or a dielectric oxide film formed by chemical conversion.

[0040] The separator 6 is made of fibers such as cellulose, polyethylene terephthalate, aramid, etc. To maintain stability at high temperatures (for example, 150° C.), the separator 6 preferably contains synthetic fibers.

[0041] In addition, an electrolyte is held between the anode foil 5 and the cathode foil 7 of the capacitor element 3. By immersing the capacitor element 3 in the electrolyte for a predetermined period of time, the electrolyte permeates the separator 6 and is held between the anode foil 5 and the cathode foil 7. The electrolyte essentially functions as a cathode. In addition, the electrolyte can repair defects in the oxide films of the anode foil 5 and the cathode foil 7.

[0042] The electrolyte solution is made of a liquid agent in which an electrolyte and a sealant deterioration inhibitor are dissolved in a lipophilic solvent. γ-butyrolactone can be used as the lipophilic solvent. Polyethylene glycol, glycerin, or polyglycerin to which a lipophilic group is bonded may also be used as the lipophilic solvent. To improve the penetration of the sealant deterioration inhibitor into the sealant 4, it is preferable that the lipophilic solvent contains γ-butyrolactone.

[0043] In addition, the solvent of the electrolyte may be sulfolane, ethylene glycol, diethylene glycol, polyethylene glycol, etc., in combination with a lipophilic solvent. In this case, an amphipathic compound may be added as necessary. As the amphipathic compound, a polyethylene glycol derivative, a polyethylene glycol-polypropylene glycol copolymer, etc. may be used.

[0044] The electrolyte dissociates into ions by dissolving in a solvent to exhibit electrical conductivity, and an organic amine salt of a boric acid compound or a carboxylic acid compound is used. As the boric acid compound, borodisalic acid ester, borodiglycolic acid ester, borodisalicylic acid ester, etc. can be used. As the carboxylic acid compound, phthalic acid, fumaric acid, adipic acid, maleic acid, etc. can be used.

[0045] As the organic amine that forms the organic amine salt, a hydrophobic organic amine such as a tertiary organic amine or a quaternary organic amine can be used. By using a hydrophobic organic amine as the organic amine contained in the electrolyte, the moisture resistance of the capacitor 1 can be improved.

[0046] Examples of such organic amines include aliphatic amines (such as triethylamine, tripropylamine, tributylamine, triamylamine, and trihexylamine), heterocyclic amines (such as pyridine and imidazole), aromatic amines, and derivatives thereof.

[0047] The sealant deterioration inhibitor is a compound that dissolves in a lipophilic solvent and permeates into the sealant 4, and is supplied to the sealant 4 from the capacitor element 3 as described below. The sealant deterioration inhibitor supplied to the sealant 4 permeates into the inside of the sealant 4 through the gaps between the molecules of the sealant 4. For simplicity, a sealant deterioration inhibitor can be a compound that is dissolved in a lipophilic solvent at a concentration of 10% and the sealant 4 is immersed in the solution for one week, and the weight of the sealant 4 after wiping off the solution on the surface is greater than that of the sealant 4 immersed in only the lipophilic solvent.

[0048] As the sealing body deterioration inhibitor, a terpenoid such as a fat-soluble vitamin having an isoprene skeleton in the molecule (including cases where the main chain of the isoprene skeleton has a single bond or double bond and a cyclic structure), an unsaturated fatty acid, a polyglycerol ester containing an unsaturated fatty acid group in the molecule, a saturated fatty acid, or a derivative thereof can be used.

[0049] Examples of fat-soluble vitamins include vitamin A, vitamin D, vitamin E, and vitamin K. Vitamin A is a compound with a carotenoid skeleton, and includes retinol, β-carotene, α-carotene, β-cryptoxanthin, and astaxanthin. Vitamin D includes vitamin D2 and vitamin D3. Vitamin E includes tocopherols (α-tocopherol, β-tocopherol, γ-tocopherol, and δ-tocopherol) and tocotrienols (α-tocotrienol, β-tocotrienol, γ-tocotrienol, and δ-tocotrienol). Vitamin K includes vitamin K1, vitamin K2, and menaquinone 7.

[0050] These fat-soluble vitamins are terpenoids that have an isoprene skeleton in the molecule, and have a strong affinity with the rubber seal 4. For this reason, it is preferable to use fat-soluble vitamins as seal deterioration inhibitors, as they improve the permeability and retention in the seal 4. The number of isoprene units in fat-soluble vitamins is preferably 2 or more, and more preferably 3 or more. Vitamin A and vitamin E are more preferable because they have a strong antioxidant effect.

[0051] Furthermore, examples of polyglycerol esters include tetraglycerol triesters in which oleic acid is used as the fatty acid group.

[0052] The electrolyte may contain additives as necessary. Examples of additives include voltage endurance improvers (polyalkylene glycol, etc.), sugar, glycerin, polyglycerin, derivatives thereof, phosphate esters, gas absorbents, hydrophilic antioxidants, etc. Hydrophilic antioxidants are difficult to permeate into the sealing body 4, so they can be retained in the capacitor element 3 for a long period of time and can suppress oxidation of the capacitor element 3.

[0053] 3, sealing body 4 is formed into a disk shape by molding an insulating elastic material, and has a pair of through holes 4a, 4b. Lead terminals 8, 9 of capacitor element 3 are inserted into through holes 4a, 4b by press-fitting. Materials that can be used as sealing body 4 include butyl rubber, isoprene rubber, silicone rubber, fluororubber, ethylene propylene rubber, and ethylene propylene diene rubber. Rubber made of a composite material containing any of these materials may also be used.

[0054] Butyl rubber is more desirable because it has high environmental resistance, such as heat aging resistance, chemical resistance, and weather resistance, high electrical insulation properties, and low gas permeability.

[0055] With the sealing body 4 placed in the opening 2b of the main case 2, the main case 2 is subjected to a drawing process to press the outer circumferential surface. As a result, a protrusion 13 that protrudes toward the inner surface of the main case 2 is formed. The outer circumferential surface of the sealing body 4 is compressed in the inward direction by the protrusion 13, so that it is tightly attached to the inner circumferential surface of the main case 2. Furthermore, the compression of the sealing body 4 causes the inner surfaces of the through holes 4a, 4b to be tightly attached to the lead terminals 8, 9. As a result, the opening 2b of the main case 2 is sealed by the sealing body 4, so that the electrolyte held in the capacitor element 3 does not leak out of the main case 2.

[0056] In addition, the open end of main case 2 is folded back to the outer surface of sealing body 4 (the surface opposite capacitor element 3) to form folded back portion 14. Folded portion 14 and protruding portion 13 prevent sealing body 4 from slipping out of main case 2.

[0057] Fig. 5 shows a detailed view of part H in Fig. 3. At least parts of separator 6 protruding toward sealing body 4 relative to anode foil 5 and cathode foil 7 are in contact with the upper surface of sealing body 4 (the surface on the capacitor element 3 side) at multiple points or surfaces while being aligned therewith.

[0058] The width of separator 6 in the short side direction is preferably 0.3 mm to 2.0 mm larger than the widths of anode foil 5 and cathode foil 7. By setting the width to 0.3 mm or more, separator 6 can bend, and the lower end of separator 6 can be reliably brought into contact with the upper surface of sealing body 4 without applying stress to anode foil 5 and cathode foil 7. Furthermore, if the width of separator 6 in the short side direction is more than 2.0 mm larger than the widths of anode foil 5 and cathode foil 7, the size of capacitor 1 will be large.

[0059] The electrolyte held in the capacitor element 3 is continuously supplied to the sealing body 4 via the separator 6. That is, the separator 6 is in contact with the sealing body 4 and constitutes a supply part that supplies the electrolyte from the capacitor element 3 to the sealing body 4.

[0060] 3, apex 13a of protrusion 13 is disposed on the side farther from capacitor element 3 than center 4c in the thickness direction of sealing body 4 (position t / 2 from the bottom end, where t is the thickness). Therefore, the outer peripheral surface of sealing body 4 is pressed from below in the figure, and the top surface (the capacitor element 3 side) of sealing body 4 is curved upwardly convexly, with the central part protruding further toward the capacitor element 3 side than the outer peripheral part. This allows separator 6 to reliably contact sealing body 4 at multiple points or surfaces while aligned with sealing body 4, thereby supplying the electrolyte.

[0061] In the presence of moisture and oxygen, the rubber forming the sealing body 4 oxidizes or pyrolyzes at high temperatures (e.g., 150°C), causing it to shrink and crack. When cracks occur in the sealing body 4, the effective thickness of the rubber is reduced, deteriorating the sealing performance. The sealing body deterioration inhibitor contained in the electrolyte of this embodiment is supplied to the sealing body 4 through the separator 6 and penetrates into the sealing body 4 through the gaps between the molecules of the sealing body 4. This reduces the permeation of oxygen and moisture, suppressing the deterioration of the sealing body 4, and also prevents the hydration deterioration of the anode foil 5 and the cathode foil 7 due to the intrusion of moisture. Therefore, a capacitor 1 with high moisture resistance can be obtained.

[0062] The molecular weight of the sealant deterioration inhibitor is preferably 3000 or less for good permeability, and more preferably 2000 or less. The molecular weight of the sealant deterioration inhibitor is preferably 200 or more for good retention of the sealant 4, more preferably 250 or more, and even more preferably 300 or more. By using a sealant deterioration inhibitor in such a molecular weight range, permeability into the sealant 4 is improved, and the effect of inhibiting sealant deterioration can be maintained for a long period of time.

[0063] In addition, it is also possible to adjust the permeability into the sealing body 4 and the durability by using two or more kinds of sealing body deterioration inhibitors with different molecular weights.

[0064] In order to properly adjust the balance between the amount of the sealing body deterioration inhibitor in the electrolyte and the amount of penetration into the sealing body 4, it is preferable that the solubility parameter (SP value) of the sealing body deterioration inhibitor is between the SP value of the lipophilic solvent and the SP value of the sealing body 4. In order to retain the sealing body deterioration inhibitor in the sealing body 4 for a long period of time, it is preferable that the boiling point of the sealing body deterioration inhibitor is higher than the boiling point of the lipophilic solvent.

[0065] Furthermore, the sealing body deterioration inhibitor is preferably a compound that is more easily oxidized than the components of the sealing body 4 in a temperature range of 150°C or less. Compounds other than those generally called antioxidants can also be used as sealing body deterioration inhibitors as long as they are more easily oxidized than the components of the sealing body 4. As such compounds, compounds that have an antioxidant effect or compounds that contain a double bond in the molecule are preferably selected. Furthermore, it is more preferable for the sealing body deterioration inhibitor to have an effect of stabilizing or eliminating the generated radicals, as this will enhance the sealing body deterioration inhibitory effect.

[0066] As a result, even if oxygen penetrates into the inside of the sealing body 4, the sealing body deterioration inhibitor is oxidized before the components of the sealing body 4, and has an anti-oxidation effect on the sealing body 4. At this time, even if oxidation or thermal decomposition of the sealing body 4 occurs, the sealing body deterioration inhibitor penetrates into the gaps between the molecules of the sealing body 4, making it difficult for the sealing body 4 to shrink. This makes it possible to suppress the occurrence of cracks in the sealing body 4.

[0067] Furthermore, because the sealant deterioration inhibitor reduces the amount of oxygen and moisture that permeates through sealant 4, the sealant deterioration inhibitor in the electrolyte is maintained for a long period of time in capacitor element 3 in a state where it is less susceptible to deterioration such as oxidation. Even if the sealant deterioration inhibitor in sealant 4 is consumed through oxidation or decomposition, the sealant deterioration inhibitor is constantly supplied to sealant 4 from capacitor element 3. This makes it possible to suppress deterioration of sealant 4 for a long period of time.

[0068] Although the sealant deterioration inhibitor is effective in suppressing deterioration of the sealant 4 even if it does not reach the outer surface of the sealant 4, it is more preferable if it reaches the outer surface of the sealant 4. This makes it possible to suppress deterioration of the sealant 4 even on the outer surface of the sealant 4 where cracks are likely to occur, and further suppresses the intrusion of oxygen and moisture.

[0069] At this time, the sealant deterioration inhibitor may form an oil film on the outer surface of the sealant 4, or may form a coating that solidifies through oxidation upon contact with oxygen in the air. The coating can further inhibit the penetration of oxygen and moisture. Silicone rubber and fluororubber are less airtight than butyl rubber, but the provision of a coating can increase the airtightness.

[0070] The concentration of the sealant deterioration inhibitor in the electrolyte is preferably 1% to 90% by weight. If the concentration of the sealant deterioration inhibitor in the electrolyte is less than 1% by weight, the effect of inhibiting oxidation of the sealant 4 cannot be sustained for a long period of time. If the concentration of the sealant deterioration inhibitor in the electrolyte exceeds 90% by weight, the viscosity of the electrolyte increases.

[0071] This lengthens the time for which the electrolyte is retained in capacitor element 3 and the time for which the electrolyte is supplied from capacitor element 3 to sealing body 4, increasing the number of steps required to manufacture capacitor 1. It is more preferable to set the concentration of the sealing body deterioration inhibitor in the electrolyte to 3% by weight to 80% by weight, as this provides a greater oxidation inhibition effect and reduces the number of steps.

[0072] The weight ratio of the sealant deterioration inhibitor in sealant 4 is preferably 0.1% to 25% by weight with respect to sealant 4. If the weight ratio of the sealant deterioration inhibitor in sealant 4 is lower than 0.1% by weight with respect to sealant 4, the gaps between the molecules of sealant 4 cannot be sufficiently filled, and the effect of suppressing moisture permeation cannot be obtained.

[0073] If the weight ratio of the sealant deterioration inhibitor in the sealant 4 is higher than 25% by weight with respect to the sealant 4, the sealant 4 may soften or change in shape. This deteriorates the sealing performance of the sealant 4 and makes it impossible to suppress the permeation of moisture. It is more preferable that the hardness (durometer hardness) of the sealant 4 after the permeation of the sealant deterioration inhibitor is 70 or more on either side of the sealant 4, since this allows the sealing performance to be maintained at a high level.

[0074] The thickness of the sealing body 4 is related to the evaporation rate of the electrolyte, the amount of moisture that permeates, and the permeability of the sealing body deterioration inhibitor. In order to keep the evaporation of the electrolyte and the amount of moisture that permeates low, the thickness of the sealing body 4 is preferably 1.4 mm or more. In order to allow the sealing body deterioration inhibitor to permeate the entire sealing body 4 and suppress the occurrence of cracks, the thickness of the sealing body 4 is preferably 7 mm or less.

[0075] The area of ​​the sealing body 4 on the capacitor element 3 side is preferably no more than twice the area of ​​contact with the separator 6 along the sealing body 4, and more preferably no more than 1.8 times. This allows the sealing body deterioration inhibitor to sufficiently permeate almost the entire surface of the sealing body 4 on the capacitor element 3 side, resulting in a capacitor 1 with a long life and high moisture resistance. The surface of the sealing body 4 on the capacitor element 3 side may be provided with irregularities to increase the contact area between the sealing body 4 and the separator 6 (supply part).

[0076] The sealant deterioration inhibitor that has permeated into almost the entire surface of the sealant 4 on the side of the capacitor element 3 can be confirmed by the following method. First, the sealant 4 from which the electrolyte has been wiped off is cut into pieces, for example, 1 mm thick and 1 mm wide in the radial direction from the outer periphery, and crushed. Next, the crushed sample is extracted with an organic solvent, and the solution is analyzed using liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS), or the like. This makes it possible to detect the sealant deterioration inhibitor.

[0077] Capacitor 1 is manufactured by sequentially performing an element formation process, an element housing process, a sealing body attachment process, a molding process, and a repair process. In the element formation process, anode foil 5 with lead terminal 8 and cathode foil 7 with lead terminal 9 are wound with separator 6 interposed therebetween, and then immersed in an electrolyte for a predetermined time to form capacitor element 3.

[0078] In the element housing process, the capacitor element 3 is inserted into the main case 2 through the opening 2b and housed therein. In the sealing body attachment process, the sealing body 4 is inserted into the main case 2 through the opening 2b and attached to the main case 2 housing the capacitor element 3. The lead terminals 8, 9 of the capacitor element 3 are inserted into the through holes 4a, 4b of the sealing body 4 by press-fitting.

[0079] In the molding process, a protruding portion 13 that protrudes toward the inner surface of the main case 2 is formed by drawing, and a folded portion 14 is formed by folding back the open end.

[0080] In the repair process, the oxide films formed on the anode foil 5 and the cathode foil 7 are repaired. The repair process is carried out, for example, by applying the rated voltage of the capacitor between the lead terminals 8 and 9 for 30 minutes in a high-temperature environment of 125°C. The high-temperature environment at this time promotes the penetration of the sealant deterioration inhibitor into the sealant 4.

[0081] According to this embodiment, capacitor element 3 holds an electrolyte (liquid agent) in which a fat-soluble sealing body deterioration inhibitor is dissolved in a lipophilic solvent, and the liquid agent supplied from capacitor element 3 by separator 6 (supply unit) permeates into sealing body 4. This makes it possible to prevent an increase in the amount of moisture permeation due to deterioration of sealing body 4 for a long period of time. This makes it possible to provide a capacitor 1 with a long life and high moisture resistance.

[0082] Furthermore, the weight ratio of the sealant deterioration inhibitor in the sealant 4 to the weight of the sealant 4 is set to 0.1% by weight to 25% by weight. This makes it possible to sufficiently fill gaps between the molecules of the sealant 4 and to prevent softening and deformation of the sealant 4. This reliably prevents moisture from passing through the sealant 4, and further improves the moisture resistance of the capacitor 1.

[0083] Furthermore, if the sealant deterioration inhibitor is a compound that is more easily oxidized than the components of sealant 4, even if oxygen penetrates into sealant 4, the sealant deterioration inhibitor will be oxidized before the components of sealant 4. This makes it possible to better prevent deterioration of sealant 4 due to oxidation, and further improve the moisture resistance of capacitor 1.

[0084] Furthermore, when the molecular weight of the sealant deterioration inhibitor is 200 to 3000, the sealant deterioration inhibitor easily permeates into the sealant 4 and has good retention properties, so that a desired amount of the sealant deterioration inhibitor can be retained inside the sealant 4. Therefore, the moisture resistance of the capacitor 1 can be further improved.

[0085] Furthermore, since the liquid agent held in capacitor element 3 is an electrolytic solution in which a sealant deterioration inhibitor and an electrolyte are dissolved in a lipophilic solvent, an electrolytic capacitor with a long life and high moisture resistance can be easily realized.

[0086] Furthermore, since the electrolyte dissolved in the lipophilic solvent contains an organic amine salt and the electrolytic solution contains a hydrophobic organic amine that forms the organic amine salt, the moisture resistance of the capacitor 1 can be further improved.

[0087] Furthermore, by using separator 6 in contact with sealing body 4, a supply section that supplies the liquid agent (electrolyte) held in capacitor element 3 to sealing body 4 can be easily realized.

[0088] Furthermore, since the central portion of the surface of sealing member 4 facing capacitor element 3 protrudes further than the outer periphery, separator 6 can be brought into contact with sealing member 4 more reliably.

[0089] Furthermore, apex 13a of protrusion 13 protruding onto the inner surface of main body case 2 is located on the side farther from capacitor element 3 than center 4c in the thickness direction of sealing body 4. This makes it possible to easily form sealing body 4 in which the central portion of the surface facing capacitor element 3 protrudes further than the outer periphery.

[0090] Furthermore, a fat-soluble sealant deterioration inhibitor that prevents deterioration of the sealant 4 due to oxidation can be easily realized by using fat-soluble vitamins such as tocopherol and tocotrienol.

[0091] Furthermore, when the lipophilic solvent is γ-butyrolactone, a liquid agent in which the sealing body deterioration inhibitor is dissolved can be easily realized.

[0092] Furthermore, if the lipophilic solvent is one in which a lipophilic group is bonded to any one of polyethylene glycol, glycerin, and polyglycerin, a liquid agent in which the sealing body deterioration inhibitor is dissolved can be easily realized.

[0093] Furthermore, when the liquid contains a lipophilic solvent, any one of sulfolane, ethylene glycol, diethylene glycol, and polyethylene glycol, and an amphipathic compound, it is possible to easily realize a liquid in which the sealing body deterioration inhibitor is dissolved.

[0094] In this embodiment, the anode foil 5 may be made of a valve metal such as tantalum, niobium, or titanium.

[0095] <Second embodiment> Next, Fig. 6 shows a front cross-sectional view of a capacitor 1 according to a second embodiment. For ease of explanation, the same parts as those in the first embodiment shown in Figs. 1 to 5 above are denoted by the same reference numerals. This embodiment differs from the first embodiment in the configuration of the supply unit that supplies the liquid agent to the sealing body 4, but the other parts are the same as those in the first embodiment.

[0096] The capacitor 1 includes a main case 2, a capacitor element 3, a sealing body 4, and a liquid supply sheet 10. The main case 2, the capacitor element 3, and the sealing body 4 are formed in the same manner as in the first embodiment.

[0097] The liquid supply sheet 10 is formed, for example, in a strip shape by papering up cellulose fibers into a sheet, and is disposed between the inner surface of the main body case 2 and the outer surface of the capacitor element 3. The liquid supply sheet 10 is provided with an absorption section 10a and a contact section 10b. The absorption section 10a is disposed facing the end wall section 2a, and contacts the separator 6 of the capacitor element 3 to absorb the electrolyte solution containing a sealant deterioration inhibitor. The contact section 10b contacts the sealant 4, and supplies the electrolyte solution absorbed from the separator 6 to the sealant 4. In other words, the liquid supply sheet 10 contacts the sealant 4 to connect the separator 6 and the sealant 4, and constitutes a supply section that supplies the electrolyte solution from the capacitor element 3 to the sealant 4.

[0098] The liquid supply sheet 10 folds both side portions from the absorbing portion 10a facing the end wall portion 2a and extends in the axial direction along the inner peripheral surface 2c of the main body case 2. The liquid supply sheet 10 extending in the axial direction protrudes toward the sealing body 4 beyond the capacitor element 3, and is folded in the radial direction to face the sealing body 4. As a result, contact portions 10b are formed at both end portions of the liquid supply sheet 10.

[0099] 7 and 8 show detailed views of part J and part K in Fig. 6. At least a part of the separator 6 protruding toward the end wall 2a side relative to the anode foil 5 and the cathode foil 7 contacts the absorbing part 10a at multiple points or a surface. In addition, contact parts 10b formed by bending both ends of the liquid supply sheet 10 in the radial direction contact the sealing body 4 at multiple points or a surface.

[0100] The electrolyte solution absorbed from the separator 6 via the absorbing portion 10a is continuously supplied to the sealing body 4 via the contact portion 10b. The electrolyte solution permeates into the sealing body 4 via the intermolecular gaps inside the sealing body 4. Therefore, the sealing body deterioration inhibitor contained in the electrolyte can suppress deterioration of the sealing body 4 due to oxidation over the long term.

[0101] Furthermore, liquid supply sheet 10 is in a swollen state due to the inclusion of the electrolyte, which reduces the range of movement of capacitor element 3 within main body case 2, thereby improving the vibration resistance of capacitor element 3.

[0102] The absorbing portion 10a facing the end wall portion 2a may be provided at one end of the liquid supply sheet 10, and the contact portion 10b may be provided at the other end. As shown in this embodiment, it is more preferable to form the liquid supply sheet 10 into a U-shape, provide the absorbing portion 10a in the center, and provide contact portions 10b at both ends, because this ensures that the sealant deterioration inhibitor can be supplied to the sealant 4.

[0103] The capacitor 1 is manufactured by sequentially carrying out an element forming step, an element housing step, a sealing body attaching step, a molding step, and a repairing step. The element forming step, the molding step, and the repairing step are the same as those described above.

[0104] 9 and 10 are a front cross-sectional view and a plan view showing the element storage step. In the element storage step, the longitudinal center of a strip-shaped liquid supply sheet 10 is placed on the opening 2b of the main case 2. The width of the short side of the liquid supply sheet 10 is formed to be the same as or slightly smaller than the inner diameter of the main case 2. Then, the capacitor element 3 is inserted into the main case 2 from above the liquid supply sheet 10, and the liquid supply sheet 10 is pressed into the main case 2.

[0105] As a result, the liquid supply sheet 10 is disposed in a U-shape between the inner surface of the main body case 2 and the outer surface of the capacitor element 3 housed in the main body case 2. The central portion in the longitudinal direction of the liquid supply sheet 10 forms an absorption portion 10a that faces the end wall portion 2a and contacts the separator 6 (see FIG. 7). In addition, both ends in the longitudinal direction of the liquid supply sheet 10 protrude toward the opening 2b side (the sealing body 4 side) beyond the capacitor element 3 housed in the main body case 2 (see FIG. 12).

[0106] 12 is a front cross-sectional view showing the sealing body attachment process. In the sealing body attachment process, sealing body 4 is inserted into main case 2 housing capacitor element 3 from the opening 2b side and attached. Lead terminals 8, 9 of capacitor element 3 are inserted into through holes 4a, 4b of sealing body 4 by press-fitting. At this time, both longitudinal ends of liquid supply sheet 10 are pressed by sealing body 4 and bent in the radial direction, forming contact portions 10b in contact with the inner surface of sealing body 4 (the surface on the capacitor element 3 side).

[0107] According to this embodiment, the capacitor element 3 holds an electrolyte (liquid agent) in which a fat-soluble sealing body deterioration inhibitor is dissolved in a lipophilic solvent, and the liquid agent supplied from the capacitor element 3 by the liquid supply sheet 10 (supply unit) permeates into the sealing body 4. This makes it possible to prevent an increase in the amount of moisture permeation due to deterioration of the sealing body 4 for a long period of time. This makes it possible to provide a capacitor 1 with a long life and high moisture resistance.

[0108] In addition, the liquid supply sheet 10, which is in contact with the sealing body 4 and connects the separator 6 to the sealing body 4, makes it easy to realize a supply section that supplies the liquid (electrolyte) held in the capacitor element 3 to the sealing body 4.

[0109] <Third embodiment> Next, a third embodiment will be described. In this embodiment, in contrast to the capacitor 1 of the first embodiment, the capacitor element 3 holds a solid electrolyte (not shown) in addition to an electrolytic solution. This makes the capacitor 1 a hybrid-type electrolytic capacitor. The other parts are the same as those of the first embodiment.

[0110] The solid electrolyte is composed of a conductive polymer. The conductive polymer can reduce the ESR of the capacitor 1. The conductive polymer is a polymer of pyrrole, thiophene, aniline, or a derivative thereof. The conductive polymer is doped with a dopant having a sulfonic acid group, such as polystyrene sulfonate. The dopant of the conductive polymer may have a sulfonic acid group substituent and be self-doped within the molecule.

[0111] Capacitor element 3 is immersed in a dispersion or aqueous solution of a conductive polymer for a predetermined time and then dried, thereby allowing a solid electrolyte layer made of a conductive polymer to be held between anode foil 5 and cathode foil 7.

[0112] Some of the sulfonic acid groups in the dispersion or aqueous solution function as dopants for the conductive polymer. The remaining sulfonic acid groups cause the conductive polymer to be dispersed or dissolved in water. Since sulfonic acid groups are strongly acidic and dissolve aluminum, for example, 70% or more of the dispersed or dissolved sulfonic acid groups are neutralized with an alkaline compound. At this time, the degree of neutralization of the sulfonic acid groups is lower than the isoelectric point (100%) so as not to deteriorate the permeability of the conductive polymer into the capacitor element 3. For this reason, free sulfonic acid groups that do not function as dopants and are not neutralized are present in the dispersion or aqueous solution.

[0113] The alkaline compound that neutralizes the sulfonic acid groups is made of a hydrophobic organic amine compound, which can improve the hydrophobicity of the conductive polymer and suppress deterioration of the characteristics of the capacitor 1 due to moisture absorption by the conductive polymer, thereby improving the moisture resistance of the capacitor 1. As the hydrophobic organic amine compound, an organic amine that dissolves in a lipophilic solvent in a non-salt state at room temperature is preferable.

[0114] The sulfonic acid group of the dopant is highly hygroscopic when it is in a free, unneutralized state. Therefore, by including a hydrophobic organic amine in the electrolyte, the sulfonic acid group after drying and forming a solid electrolyte is neutralized by the hydrophobic organic amine to form a hydrophobic organic amine salt. An electrolyte containing a lipophilic solvent and an organic amine that dissolves in it can quickly neutralize the sulfonic acid group of the dopant by contacting the conductive polymer.

[0115] In this case, a part of the organic amine neutralizing the sulfonic acid group is an organic amine derived from the solute of the electrolyte. By making both the organic amine neutralizing the dopant and the organic amine in the electrolyte hydrophobic, the moisture resistance of the capacitor 1 can be further improved.

[0116] The electrolyte consists of a liquid agent in which a seal deterioration inhibitor and an electrolyte are dissolved in a lipophilic solvent, as described above, and covers at least a part of the solid electrolyte layer. The electrolyte is an organic amine salt of a boric acid compound or a carboxylic acid compound. If a boric acid compound is included, it is preferable because the hybrid type capacitor 1 has a long life.

[0117] As the organic amine forming the organic amine salt of the electrolyte, it is preferable to include a hydrophobic organic amine as described above. In this case, the organic amine in the electrolyte may be the same as or different from the organic amine neutralizing the sulfonic acid group of the dopant. In addition, multiple types of organic amines may be used in combination.

[0118] By using a hydrophobic organic amine, the hydrophilicity of the sealing member 4, the electrolyte, and the conductive polymer is reduced. This allows the moisture resistance of the capacitor 1 to be maintained in a high-temperature environment (e.g., 150°C). It is preferable that the organic amine contained in the electrolyte does not contain a hydrophilic organic amine. This allows the moisture resistance of the capacitor 1 to be maintained even if the amine neutralizing the sulfonic acid group of the dopant is replaced.

[0119] Furthermore, since the solid electrolyte is swollen by the electrolytic solution, the solid electrolyte adheres more closely to the anode foil 5 and the cathode foil 7 which sandwich the solid electrolyte, thereby enabling the ESR of the capacitor 1 to be reduced.

[0120] The electrolyte may also contain a hydrolyzable ester compound. As the hydrolyzable ester compound, a borate ester compound, a carboxylate ester compound, or a phosphate ester compound can be used. The hydrolyzable ester compound is hydrolyzed in the presence of moisture. The borate ester compound is hydrolyzed to boric acid and alcohol, or boric acid and a carboxylic acid. The carboxylate ester compound is hydrolyzed to a carboxylic acid and alcohol. The phosphate ester compound is hydrolyzed to phosphoric acid and alcohol. This reaction is promoted in a weakly acidic electrolyte. Since the moisture in the capacitor 1 is consumed by the hydrolysis of the hydrolyzable ester compound, the excess moisture in the electrolyte can be reduced, and the moisture resistance of the capacitor 1 can be further improved.

[0121] Examples of the carboxylate ester include phthalate ester, maleate ester, adipate ester, etc. The carboxylate ester compound can generate a carboxylic acid by hydrolysis, which can become an electrolyte of the electrolytic solution.

[0122] Examples of the borate ester compound include borodisalic acid ester, borodiglycolic acid ester, borodisalicylic acid ester, etc. The borate ester compound can also serve as an electrolyte in the electrolytic solution.

[0123] When the electrolyte contains a borate ester compound, the concentration of the borate ester compound in the electrolyte is preferably 0.1% by weight to 20% by weight. If the concentration of the borate ester compound in the electrolyte is lower than 0.1% by weight, the effect of keeping the moisture constant is insufficient. If the concentration of the borate ester compound in the electrolyte exceeds 20% by weight, products generated by hydrolysis are precipitated on the fibers of the separator 6 and on the surface of the anode foil 5 or cathode foil 7, deteriorating the characteristics of the capacitor 1.

[0124] Next, a durability test was performed on the capacitor 1 of this embodiment. The electrolyte of the capacitor 1 of this embodiment that was tested uses γ-butyrolactone as a lipophilic solvent, triethylamine borodisalicylate as an electrolyte, and α-tocopherol as a sealant deterioration inhibitor. The concentration of the sealant deterioration inhibitor in the electrolyte is 10% by weight. In addition, a capacitor element 3 having a diameter of 9.0 mm was immersed in a conductive polymer dispersion liquid of polyethylenedioxythiophene using polystyrenesulfonic acid as a dopant, and then pulled up and dried to form a solid electrolyte layer. The sealant 4 is formed of butyl rubber and has a diameter of 9.2 mm and a thickness of 2.7 mm.

[0125] Also, as a comparative example, a capacitor was used in which the sealant deterioration inhibitor was omitted from the electrolyte of the sample capacitor 1 of this embodiment.

[0126] Twenty capacitors 1 each of the present embodiment and the comparative example were left in a high-temperature environment at 150° C. for 2000 hours. As a result, cracks with a depth of about 1 / 3 of the thickness occurred in the sealing body 4 of five capacitors in the comparative example. In contrast, no cracks visible to the naked eye occurred in the sealing body 4 of any of the capacitors 1 of the present embodiment.

[0127] Next, a high temperature and humidity load test was conducted on 20 capacitors 1 of this embodiment and 5 capacitors of the comparative example that had cracks in the above test. In the high temperature and humidity load test, the rated voltage was applied in an environment of a temperature of 85°C and a relative humidity of 85%, and the ESR was measured every 1000 hours. Figure 12 shows the results, with the vertical axis representing ESR (unit: mΩ) and the horizontal axis representing elapsed time (unit: hours). In the figure, A represents capacitor 1 of this embodiment, and B represents the comparative example capacitor.

[0128] As a result, the ESR of the comparative example increased rapidly after 2000 hours, but the capacitor 1 of this embodiment showed a low ESR up to 6000 hours. This allows the capacitor 1 of this embodiment to exhibit high moisture resistance and stable characteristics over the long term.

[0129] According to this embodiment, similarly to the first embodiment, the electrolyte (liquid) supplied from the capacitor element 3 by the separator 6 (supply unit) permeates into the sealing body 4. This makes it possible to prevent an increase in the amount of moisture permeation due to deterioration of the sealing body 4 for a long period of time. This makes it possible to provide a capacitor 1 with a long life and high moisture resistance.

[0130] In addition, since the conductive polymer contains a dopant having a sulfonic acid group and the electrolyte contains a hydrophobic organic amine, the sulfonic acid is neutralized by the hydrophobic organic amine, which prevents deterioration of the characteristics of the capacitor 1 due to moisture absorption by the conductive polymer and improves the moisture resistance of the capacitor 1.

[0131] In addition, since the conductive polymer dopant has a sulfonic acid group substituent and the electrolytic solution contains a hydrophobic organic amine, the sulfonic acid is neutralized by the hydrophobic organic amine, which prevents the performance degradation of the capacitor 1 caused by moisture absorption by the conductive polymer and improves the moisture resistance of the capacitor 1.

[0132] Furthermore, since the electrolytic solution contains a hydrolyzable ester compound, excess moisture in the electrolytic solution can be reduced by hydrolysis of the hydrolyzable ester compound, thereby further improving the moisture resistance of the capacitor 1.

[0133] Furthermore, when the concentration of the borate ester compound in the electrolyte is set to 0.1% by weight to 20% by weight, the moisture content in the capacitor 1 can be kept constant and deterioration of the characteristics of the capacitor 1 due to precipitates produced by hydrolysis can be prevented.

[0134] In this embodiment, the electrolyte may be supplied to the sealing body 4 by a liquid supply sheet 10, as in the second embodiment.

[0135] <Fourth embodiment> Next, a fourth embodiment will be described. In this embodiment, in comparison with the capacitor 1 of the first embodiment, the capacitor element 3 holds a solid electrolyte (not shown) and a predetermined liquid agent instead of an electrolytic solution. The other parts are the same as those of the first embodiment.

[0136] The solid electrolyte held in capacitor element 3 is made of a conductive polymer similar to that in the third embodiment.

[0137] A liquid agent in which a sealing body deterioration inhibitor is dissolved in a lipophilic solvent is held between the anode foil 5 and the cathode foil 7. The lipophilic solvent and the sealing body deterioration inhibitor may be the lipophilic solvent and the fat-soluble sealing body deterioration inhibitor contained in the electrolyte of the first embodiment.

[0138] The liquid agent held in capacitor element 3 is supplied to sealing body 4 via separator 6 and permeates into the inside of sealing body 4. This makes it possible to prevent deterioration of sealing body 4. Therefore, the liquid agent held in capacitor element 3 constitutes a functional liquid that has the function of improving the moisture resistance of capacitor 1.

[0139] The functional liquid may also contain a pressure resistance improver or a conductivity improver. As the pressure resistance improver, polyalkylene glycol or the like can be used. As the conductivity improver, a compound containing a hydroxyl group, such as sugar or glycerin, can be used.

[0140] In addition, the solid electrolyte is swollen by the functional liquid, and this increases the adhesion of the solid electrolyte to the anode foil 5 and the cathode foil 7 that sandwich the solid electrolyte. This reduces the ESR of the capacitor 1. Therefore, the functional liquid also has the function of reducing the ESR of the capacitor 1.

[0141] The functional liquid may also have a function of enhancing other properties of the capacitor 1 .

[0142] According to this embodiment, similarly to the first embodiment, the capacitor element 3 holds a functional liquid (liquid agent) in which a fat-soluble sealing body deterioration inhibitor is dissolved in a lipophilic solvent, and the liquid agent supplied from the capacitor element 3 by the separator 6 (supply unit) permeates into the sealing body 4. This makes it possible to suppress an increase in the amount of moisture permeation due to deterioration of the sealing body 4 for a long period of time. Therefore, it is possible to provide a capacitor 1 with a long life and high moisture resistance.

[0143] In this embodiment, the functional liquid may be supplied to the sealing body 4 by the liquid supply sheet 10 in the same manner as in the second embodiment.

[0144] In the first to fourth embodiments, in other capacitors such as an electric double layer capacitor, the liquid agent supplied from the capacitor element may be allowed to permeate into the inside of the sealing body 4. Furthermore, although the electrodes (anode foil 5 and cathode foil 7) of the capacitor element 3 are wound facing each other with separator 6 interposed therebetween, the pair of electrodes facing each other with the separator interposed therebetween may be flat. [Industrial Applicability]

[0145] The present invention can be used in capacitors such as electrolytic capacitors, and in automobiles, electronic devices, and the like in which capacitors are mounted in circuits. [Explanation of symbols]

[0146] 1 Capacitor 2 Main unit case 2a End wall 2b opening 2c Inner surface 3 Capacitor elements 4 Sealing body 4a, 4b through hole 5 Anode foil 6 Separator 7 Cathode foil 8, 9 Lead terminal 10 Liquid supply sheet 10, 11 Through holes 10a Absorption section 10b Contact part 12 Tape 13 Protrusion 13a Vertex 14 Folding part 15 Seat board 15a, 15b through hole

Claims

1. A capacitor comprising a capacitor element holding a predetermined liquid between a pair of electrodes facing each other via a separator, a main case that houses the capacitor element, and a rubber seal that seals the main case, wherein the liquid contains a sealant deterioration inhibitor, the concentration of the sealant deterioration inhibitor in the liquid is 1% to 90% by weight, the sealant deterioration inhibitor is supplied from the capacitor element and permeates the entire sealant, and the thickness of the sealant is 1.4 mm or more and 7 mm or less.

2. 2. The capacitor according to claim 1, wherein the sealant deterioration inhibitor is a compound that is more easily oxidized than the components of the sealant.

3. 3. The capacitor according to claim 1, wherein the sealing body deterioration inhibitor has a molecular weight of 200 to 3,000.

4. 4. The capacitor according to claim 1, wherein the liquid agent is an electrolytic solution in which the sealing body deterioration inhibitor and an electrolyte are dissolved in a lipophilic solvent.

5. 5. The capacitor according to claim 4, wherein the electrolyte includes an organic amine salt, and the electrolytic solution includes a hydrophobic organic amine that forms the organic amine salt.

6. 6. The capacitor according to claim 5, wherein the capacitor element holds a solid electrolyte made of a conductive polymer, the conductive polymer containing a dopant having a sulfonic acid group.

7. 6. The capacitor according to claim 5, wherein the capacitor element holds a solid electrolyte made of a conductive polymer, and the conductive polymer dopant has a sulfonic acid group as a substituent.

8. 6. The capacitor according to claim 4, wherein the capacitor element holds a solid electrolyte made of a conductive polymer, and the electrolytic solution contains a hydrolyzable ester compound.

9. 9. The capacitor according to claim 8, wherein the hydrolyzable ester compound is a borate ester compound, and the concentration of the borate ester compound in the electrolyte is 0.1% by weight to 20% by weight.

10. The capacitor according to any one of claims 1 to 3, wherein the capacitor element holds a solid electrolyte made of a conductive polymer.

11. a supply unit that supplies the liquid from the capacitor element to the sealing body, 11. The capacitor according to claim 1, wherein the supply portion is formed by the separator, and the separator is in contact with the sealing member.

12. The capacitor according to claim 11, wherein a central portion of the surface of the sealing body facing the capacitor element protrudes beyond an outer periphery.

13. The capacitor described in claim 12, characterized in that the main body case has a protrusion that protrudes from an inner surface and presses against an outer peripheral surface of the sealing body, and an apex of the protrusion is positioned away from the capacitor element relative to the center of the thickness direction of the sealing body.

14. a supply unit that supplies the liquid from the capacitor element to the sealing body, The capacitor according to any one of claims 1 to 10, wherein the supply section connects the separator and the sealing body.

15. The solubility parameter of the sealing body deterioration inhibitor is between the solubility parameter of the lipophilic solvent and the solubility parameter of the sealing body 4, The concentration of the sealing body deterioration inhibitor in the liquid agent is 3% by weight to 80% by weight, 10. The capacitor according to claim 4, wherein the sealant deterioration inhibitor is a fat-soluble vitamin.

16. 16. The capacitor of claim 15, wherein the fat-soluble vitamin is a tocopherol or a tocotrienol.

17. 10. The capacitor according to claim 4, wherein the lipophilic solvent is γ-butyrolactone.

18. 10. The capacitor according to claim 4, wherein the lipophilic solvent is one selected from the group consisting of polyethylene glycol, glycerin, and polyglycerin to which a lipophilic group is bonded.

19. The capacitor according to any one of claims 4 to 9, characterized in that the liquid agent contains the lipophilic solvent, any one of sulfolane, ethylene glycol, diethylene glycol, and polyethylene glycol, and an amphipathic compound.

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