WO2024062720A1

WO2024062720A1 - Electrolytic capacitor and method for manufacturing same

Info

Publication number: WO2024062720A1
Application number: PCT/JP2023/024766
Authority: WO
Inventors: 伊藤慎一郎
Original assignee: エルナー株式会社
Priority date: 2022-09-22
Filing date: 2023-07-04
Publication date: 2024-03-28
Also published as: JP2024046426A

Abstract

An electrolytic capacitor characterised by comprising a capacitor element in which an anode foil and a cathode foil are wound with a separator interposed therebetween, the separator being configured to hold a conductive polymer layer, the separator being mainly formed from glass fibers having a porosity of 75% to 90%.

Description

Electrolytic capacitor and its manufacturing method

The present invention relates to an electrolytic capacitor using a conductive polymer and a method for manufacturing the same.

An electrolytic capacitor has a structure in which an anode foil and a cathode foil, for example, aluminum foil, are wound around a capacitor element with an electrolyte impregnated with an electrolyte, and the capacitor element is assembled together with a sealing member into an exterior case. Examples of aluminum electrolytic capacitors using conductive polymers include solid electrolytic capacitors that hold a conductive polymer within the capacitor element, and hybrid electrolytic capacitors that hold a conductive polymer and electrolyte within the capacitor element (patented). (See references 1 and 2).

Japanese Patent Application Publication No. 2022-59471 International Publication No. 2017/090241

For example, separators such as cellulose fibers conventionally used in aluminum electrolytic capacitors using conductive polymers have low acid resistance and are decomposed by strongly acidic polymers. When manufacturing solid electrolytic capacitors using this type of separator, for example, in the process of chemically polymerizing monomers with an oxidizing agent to generate a conductive polymer layer, there is a risk that the fibers of the separator will rapidly deteriorate due to the effects of chemical polymerization. There is.

In addition, unlike this, even if a conductive polymer layer is generated by immersing a capacitor element in a conductive polymer dispersion and drying it, the separator may be damaged due to elution of the conductive polymer after manufacturing. deteriorates rapidly. For example, in the case of a hybrid electrolytic capacitor in which a conductive polymer layer is formed using the above dispersion liquid, the conductive polymer is likely to be eluted into the electrolytic solution contained in the separator. As the electrolytic solution evaporates, the acidity of the electrolytic solution increases due to the conductive polymer eluted into the electrolytic solution from the conductive polymer layer, so the deterioration of the separator becomes faster and decomposition is promoted.

As decomposition progresses due to acidification of the separator in this way, for example, there is a possibility that the amount of retained conductive polymer progresses and the ESR increases. Furthermore, there is a possibility that the amount of electrolyte retained will decrease and leakage current will also increase.

Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a highly reliable electrolytic capacitor that suppresses acidification of a separator, and a method for manufacturing the same.

The electrolytic capacitor of the present invention has a capacitor element in which an anode foil and a cathode foil are wound around a separator that holds a conductive polymer layer, and the separator has a porosity of 75 to 90 (%). It is characterized by being mainly made of glass fiber.

In the above electrolytic capacitor, the glass fiber may have a porosity of 85 to 90 (%).

In the above electrolytic capacitor, the separator may hold an electrolytic solution, and the average fiber diameter of the glass fibers may be 0.5 to 1 (μm).

In the above electrolytic capacitor, the glass fiber may include at least one of borosilicate glass, alkali-free borosilicate glass, and high silica glass.

In the above electrolytic capacitor, the separator may include at least one of polyester fibers, polyethylene fibers, polypropylene fibers, aramid fibers, acrylic fibers, and cellulose fibers.

In the above electrolytic capacitor, the separator may contain as a binder at least one of polyvinyl alcohol, polyvinyl butyral, polyvinylpyrrolidone, polyurethane, polyvinylidene fluoride, styrene-butadiene rubber, and acrylic resin.

In the above electrolytic capacitor, the capacitor element may be impregnated with the electrolytic solution containing at least one of ethylene glycol, γ-butyrolactone, and sulfolane.

The method for manufacturing an electrolytic capacitor of the present invention includes the steps of winding an anode foil and a cathode foil through a separator to produce a capacitor element, immersing the capacitor element in a dispersion or solution of a conductive polymer, and drying the capacitor element, and the separator is characterized by being mainly made of glass fiber with a porosity of 75 to 90 (%).

In the above manufacturing method, the glass fiber may have a porosity of 85 to 90 (%).

The above manufacturing method may further include a step of immersing the capacitor element in an electrolyte, and the average fiber diameter of the glass fibers may be 0.5 to 1 (μm).

In the above manufacturing method, the glass fiber may include at least one of borosilicate glass, alkali-free borosilicate glass, and high silica glass.

In the above manufacturing method, the separator may include at least one of polyester fibers, polyethylene fibers, polypropylene fibers, aramid fibers, acrylic fibers, and cellulose fibers.

In the above manufacturing method, the separator may contain as a binder at least one of polyvinyl alcohol, polyvinyl butyral, polyvinylpyrrolidone, polyurethane, polyvinylidene fluoride, styrene-butadiene rubber, and acrylic resin.

In the above manufacturing method, the capacitor element may be impregnated with the electrolytic solution containing at least one of ethylene glycol, γ-butyrolactone, and sulfolane.

According to the present invention, acidification of the separator can be suppressed and reliability can be improved.

FIG. 2 is a side view showing an example of an aluminum electrolytic capacitor. FIG. 2 is a perspective view showing an example of a capacitor element. It is a figure showing an example of a manufacturing process of an aluminum electrolytic capacitor.

[Embodiment]
(Configuration of aluminum electrolytic capacitor)
FIG. 1 is a side view showing an example of an aluminum electrolytic capacitor 1. As shown in FIG. In the paper of FIG. 1, a cross section of the inside of the aluminum electrolytic capacitor 1 is shown in the right half of the aluminum electrolytic capacitor 1 across the center line L.

Aluminum electrolytic capacitor 1 is a conductive polymer solid electrolytic aluminum capacitor (hereafter referred to as a solid electrolytic capacitor) or a conductive polymer hybrid aluminum electrolytic capacitor (hereafter referred to as a hybrid electrolytic capacitor). Aluminum electrolytic capacitor 1 is mounted on an electronic circuit board and is used, for example, for coupling, decoupling, smoothing, etc.

The aluminum electrolytic capacitor 1 includes a capacitor element 10, a case 11, a sealing body 12, a seat plate 13, a pair of round bar parts 111, and a pair of lead parts 110. The round bar part 111 and the lead part 110 are lead electrodes of the capacitor element 10, and the lead part 110 extends from the tip of the round bar part 111. In addition, although only one round bar part 111 is shown in FIG. 1, the other round bar part 111 is provided at a symmetrical position across the center line L.

The case 11 is made of aluminum and has a cylindrical shape with a closed upper opening. Case 11 covers capacitor element 10 and sealing body 12 and functions as an exterior of aluminum electrolytic capacitor 1 . Note that the shape of the case 11 is not limited to a cylindrical shape, but may be a rectangular tube shape.

The sealing body 12 is a substantially circular member made of an elastic member such as butyl rubber, for example. The sealing body 12 is adjacent to the capacitor element 10 and seals the opening at the bottom of the case 11 .

As described later, the capacitor element 10 has a structure in which an anode foil, a cathode foil, and a separator (electrolytic paper) are layered and wound. A pair of round bar portions 111 extend from the bottom of the capacitor element 10 .

The round bar portion 111 and the lead portion 110 are rod-shaped members made of aluminum or the like. The pair of round bar parts 111 are respectively joined to the anode foil and the cathode foil by a joining means such as caulking, and function as an anode terminal and a cathode terminal of the aluminum electrolytic capacitor 1. Each round bar portion 111 is inserted into a pair of through holes 120 formed in the sealing body 12, respectively. Although only one through hole 120 is shown in FIG. 1, the other through hole 120 is provided at a symmetrical position with the center line L interposed therebetween.

The lead portion 110 has a flat plate shape and is bent into an L shape, with its tip portion extending along the surface of the base plate 13. The portion of the lead portion 110 on the round bar portion 111 side is inserted into the through hole 130 of the base plate 13. The lead portion 110 is soldered to a pad on the electronic circuit board during the reflow process of the electronic circuit board.

The seat plate 13 is a plate-like member made of resin or the like, and is provided below the case 11 and the sealing body 12. The seat plate 13 supports the case 11 and the sealing body 12 with respect to the electronic circuit board to be mounted. The seat plate 13 is provided with a through hole 130 of the lead portion 110 and a groove portion 131 for accommodating the bent tip portion of the lead portion 110. The groove portion 131 extends along the bottom surface of the seat plate 13 from near the center to the outside. Since the bottom surface of the seat plate 13 becomes the mounting surface of the aluminum electrolytic capacitor 1 on the electronic circuit board, it becomes possible to solder the plate-shaped lead portion 110 to the pad on the electronic circuit board. In this embodiment, a surface mount type aluminum electrolytic capacitor 1 is used, but the embodiments described later can also be applied to a lead type capacitor without a seat plate 13.

(Configuration of capacitor element)
FIG. 2 is a perspective view showing an example of the capacitor element 10. In FIG. 2, components common to those in FIG. 1 are denoted by the same reference numerals, and their explanations will be omitted. The capacitor element 10 includes a wound body 100 in which an anode foil 101, a cathode foil 102, and a separator (electrolytic paper) 103 are wound, and a pair of extraction electrodes 19 connected to the anode foil 101 and the cathode foil 102.

A pair of extraction electrodes 19 extend below the wound body 100. The round bar portion 111 of each extraction electrode 19 is connected to the anode foil 101 and the cathode foil 102, respectively. Note that FIG. 2 shows the state before the lead portion 110 is bent and pressed into a flat plate shape.

The anode foil 101 and the cathode foil 102 are formed of valve metals such as aluminum, tantalum, titanium, and niobium, alloy foils thereof, vapor-deposited foils, and the like. The surface of the anode foil 101 is etched to increase the electrode area. Thereby, the capacitor element 10 secures a predetermined capacitance. Furthermore, an extremely thin oxide film is formed on the surface of the anode foil 101. Therefore, the anode foil 101 is insulated from other members. The capacitor element 10 functions as a capacitor because the oxide film functions as a dielectric.

On the other hand, although the surface of the cathode foil 102 has been subjected to etching treatment, no oxide film is formed thereon. Note that an oxide film, an inorganic layer, or a carbon layer may be formed on the surface of the cathode foil 102.

The separator 103 is wound while being sandwiched between the anode foil 101 and the cathode foil 102. The separator 103 holds a conductive polymer in the case of a solid electrolytic capacitor, and holds a conductive polymer and an electrolyte in the case of a hybrid electrolytic capacitor. The separator 103 is mainly formed of glass fibers with a porosity of 75 to 90 (%), and may contain other organic fibers, binders, etc. in addition to glass fibers. As described above, since the separator 103 is mainly made of glass fibers, it is less likely to become acidic than, for example, when cellulose fibers are used mainly.

The porosity of glass fiber is 75 to 90 (%). Here, the porosity is the ratio of the volume of voids to the volume of the entire fiber. When the porosity is less than 75 (%), the ESR increases because the glass fibers cannot hold a sufficient amount of the conductive polymer and electrolyte. Further, when the porosity exceeds 90 (%), the glass fibers can hold a sufficient amount of the conductive polymer and electrolyte, so the ESR is sufficiently reduced, but on the other hand, the separator 103 This is not suitable as it will not be able to maintain the necessary strength during winding.

Therefore, when the porosity of the glass fiber is 75 to 90 (%), the amount of the conductive polymer and electrolyte retained increases, and the ESR is appropriately reduced. Preferably, when the porosity of the glass fiber is set to 85 to 90 (%), more conductive polymer can be retained, thereby further reducing ESR. This increases the reliability of the aluminum electrolytic capacitor 1.

Furthermore, the average fiber diameter of the glass fibers is 0.5 to 1 (μm). If the fiber diameter exceeds 1 (μm), the evaporation rate of the electrolyte becomes excessively high, and the density of the conductive polymer eluted from the conductive polymer layer into the electrolyte increases, resulting in acidification of the separator. proceed. On the other hand, when the fiber diameter is less than 0.5 (μm), the retention of the conductive polymer deteriorates, which is not appropriate. Therefore, by setting the average fiber diameter of the glass fibers to 0.5 to 1 (μm), evaporation of the electrolytic solution is appropriately suppressed and acidification is suppressed.

Furthermore, the thickness of the separator 103 is 40 (μm). If the thickness of the separator 103 is less than 40 (μm), it is excessively thin and has a low withstand voltage.

The glass fiber includes at least one of borosilicate glass, alkali-free borosilicate glass, and high silica glass. By using these materials as the main body of the separator 103, there is an advantage that acid resistance is improved.

Furthermore, the separator 103 may include at least one of polyester fibers, polyethylene fibers, polypropylene fibers, aramid fibers, acrylic fibers, and cellulose fibers. By including these materials in the separator 103, the advantages of excellent solvent resistance and improved mechanical strength such as tensile strength can be obtained.

Furthermore, the separator 103 may contain as a binder at least one of polyvinyl alcohol, polyvinyl butyral, polyvinylpyrrolidone, polyurethane, polyvinylidene fluoride, styrene-butadiene rubber, and acrylic resin. By including these binders in the separator 103, advantages such as excellent solvent resistance and improved mechanical strength such as tensile strength can be obtained.

Further, when the aluminum electrolytic capacitor 1 is a solid electrolytic capacitor, the separator 103 is impregnated with an electrolytic solution. The solvent of the electrolyte may include at least one of ethylene glycol, γ-butyrolactone, and sulfolane. By impregnating the separator 103 with the electrolytic solution used as these solvents, an advantage of lower evaporation than before can be obtained.

(Manufacturing process of electrolytic capacitor)
FIG. 3 is a diagram showing an example of the manufacturing process of the aluminum electrolytic capacitor 1. The manufacturing process of the aluminum electrolytic capacitor 1 is an example of a method of manufacturing an electrolytic capacitor. In this example, the manufacturing process of a hybrid electrolytic capacitor will be described, but the following step St6 is omitted in the method of manufacturing a solid electrolytic capacitor.

First, an anode foil 101, a cathode foil 102, and a separator 103 are prepared (step St1). The surface of the anode foil 101 is etched, and an oxide film is further formed as a dielectric layer. Further, the separator 103 has a porosity of 75 to 90 (%) and is mainly made of glass fiber. Here, the porosity is preferably 85 to 90 (%). Further, it is preferable that the average fiber diameter of the glass fibers is 0.5 to 1 (μm) from the viewpoint of good evaporation rate of the electrolytic solution and impregnation of the conductive polymer. Further, the thickness of the separator 103 is 40 (μm).

Next, the separator 103, the anode foil 101, the cathode foil 102, and the separator 103 are laminated in this order and wound, and the outer surface is fixed with a tape to produce the wound body 100 (Step St2). During winding, the lead electrodes 19 are connected to appropriate positions of the anode foil 101 and the cathode foil 102, respectively. Examples of the connection means include, but are not limited to, caulking.

Next, the wound body 100 is immersed in a conductive polymer dispersion containing water and an organic solvent for 20 minutes in a reduced pressure atmosphere, and then the wound body 100 is pulled up from the conductive polymer dispersion (Step St3). . By doing so, the wound body 100 can be impregnated with the conductive polymer. Note that in this step, a conductive polymer solution may be used instead of the conductive polymer dispersion.

Next, the rolled body 100 is placed in a drying oven at, for example, 150 degrees and dried for 60 minutes (Step St4). As a result, a conductive path is formed by fixing the conductive polymers in the separator 103 to each other to generate a conductive polymer layer.

Next, the wound body 100 is impregnated with a predetermined amount of electrolytic solution in a reduced pressure atmosphere (Step St5). Note that the electrolytic solution may be a mixture of a solute and a conductive polymer dispersion. That is, a conductive polymer dispersion can be used as an electrolyte. In that case, the impregnation with the electrolytic solution will be performed simultaneously with the impregnation with the conductive polymer.

Then, the wound body 100 is housed in the case 11 and sealed with the sealing body 12 (step St6). At this time, the extraction electrode 19 extending from the wound body 100 is inserted into the through hole 120 of the sealing body 12. After that, an aging process may be performed while applying the rated voltage to the capacitor element 10. In this manner, the manufacturing process of the aluminum electrolytic capacitor 1 is performed.

Next, an example of the aluminum electrolytic capacitor 1 will be described. Sample No. 1 of aluminum electrolytic capacitor 1 was produced according to the above manufacturing method. 1 to 8 were produced. For comparison, sample No. 1 of an aluminum electrolytic capacitor in which the main body of the separator 103 is made of special rayon fiber (finely divided cellulose fiber) and cellulose fiber instead of glass fiber is shown. 9 and 10 were prepared, respectively. Sample No. The rated voltage and capacitance of 1 to 10 are 63 (V) and 56 (μF), respectively. Further, the diameter of the case 11 was 10 (mm), and the height of the case 11 was 10 (mm). A specific method for manufacturing the aluminum electrolytic capacitor 1 will be described below.

(Preparation of rolled body)
The anode lead electrode was connected to the anode foil that had been etched and had an oxide film formed on it. A cathode lead electrode was connected to a cathode foil that had a conductor layer on its end face and was pretreated to improve wettability. Thereafter, a separator, a cathode foil, a separator, and an anode foil were laminated in this order, and each lead-out electrode was wound while being wound, and the outer surface was fixed with a tape to produce a wound body. The thickness of the separator, the fiber diameter and porosity of the main fibers of the separator were varied for each sample.

The prepared wound body is immersed in an aqueous ammonium phosphate solution, and a predetermined voltage is applied to the anode foil while chemical conversion treatment is performed again at 85°C, thereby forming a dielectric layer mainly on the end face of the anode foil. was formed.

(Impregnation of conductive polymer)
The wound body was immersed in a dispersion of a conductive polymer contained in a predetermined container in a reduced pressure atmosphere (-93 kPa), and then pulled up from the dispersion. Next, the rolled body impregnated with the conductive polymer was dried for 60 minutes in a drying oven at 150° C. to adhere the conductive polymers of each layer to each other to form conductive paths. In this way, a capacitor element functioning as a solid electrolytic capacitor was manufactured.

(Impregnation of electrolyte)
Furthermore, the above capacitor element was impregnated with a predetermined amount of electrolytic solution (ESE2 manufactured by Teika Co., Ltd.) in a reduced pressure atmosphere. As a result, a capacitor element that functions as a hybrid aluminum electrolytic capacitor was fabricated.

(Sealing of capacitor element)
The capacitor element impregnated with the electrolytic solution was sealed to complete the electrolytic capacitor. Thereafter, an aging treatment was performed for a predetermined time at a predetermined temperature while applying a rated voltage.

(evaluation)
Sample No. 1 to 10 were evaluated as solid electrolytic capacitors and hybrid electrolytic capacitors. Using an LCR meter for four-terminal measurements, the ESR (mΩ) of the solid electrolytic capacitor and the hybrid electrolytic capacitor were measured when the frequency of the electrolytic capacitor was 100 kHz in an environment of 20° C. Furthermore, the amount of retained polymer (conductive polymer) (g) was measured as an evaluation of the solid electrolytic capacitor, and the rate of evaporation of the electrolyte at 150° C. (g/h) was measured as an evaluation of the hybrid electrolytic capacitor. Table 1 shows the measurement results for the solid electrolytic capacitor, and Table 2 shows the measurement results for the hybrid electrolytic capacitor.

Table 1 shows sample no. The evaluation results as solid electrolytic capacitors of 1 to 10 are shown below. Sample No. The main body of separators 1 to 8 was glass fiber, and sample No. Separators No. 9 and No. 10 were mainly made of special rayon fiber and cellulose fiber, respectively. Further, the ratio of the weight of the main fiber to the weight of the entire separator (see weight ratio in Table 1) is as follows for sample No. 9 and 10 are 100 (%), and sample No. 4 was 65 (%), and the others were 75 (%).

The fiber diameter is the average diameter of the main fibers of the separator, and was measured by planar measurement of the separator at 5000 times magnification using a scanning electron microscope (SEM). Sample No. The fiber diameter of samples 1 to 4, 6, and 8 was 0.5 (μm), and sample No. The fiber diameter of sample No. 5 was 1.2 (μm). The fiber diameter of No. 7 was 1.0 (μm). Sample No. The fiber diameter of Sample No. 9 was 2.0 (μm). The fiber diameter of No. 10 was 5.0 (μm). Also, sample No. The thickness of the separator of Sample No. 6 was 30 (μm), and the thickness of the separator of the other samples was 40 (μm).

The porosity of the separator was varied for each sample. Sample No. For Nos. 1 to 4 and 8, the higher the porosity of the separator, the higher the amount of polymer retained and the lower the ESR. However, sample no. 5 and 7 are sample nos. Although the porosity was lower than that of No. 4, the fiber diameter was larger and the impregnating property of the polymer was improved, so the amount of polymer retained was increased and the ESR was lowered. Also, sample No. 6 is sample No. Although the porosity was lower than that of No. 4, the ESR was lower because the thickness was thinner and the conductive path was shorter.

Sample No. which is a comparative example. Based on the ESR of 9 and 10, sample No. 9 and 10 of Example. The ESR of 1 to 8 was judged to be pass/fail (OK/NG) (see the judgment results in the table). Sample No. ESR of 1 to 7 is sample no. Since it was lower than the ESR of 9 and 10, it was determined to be OK. Also, sample No. 8 is sample No. The thickness is the same as that of sample No. 9. Although the porosity was higher than that of Sample 9, the ESR was high, so it was judged as NG. Furthermore, sample No. with a porosity of 90(%). 1 and sample No. 1 with a porosity of 85 (%). Since Sample No. 2 had a large amount of polymer retained, the ESR was further suitably reduced.

Therefore, sample No. with a porosity of 75 to 90 (%). The ESR of 1 to 7 was suitably reduced. Furthermore, sample No. with a porosity of 85 to 90 (%). The ESR of 1 and 2 was suitably reduced.

Also, the thickness of sample No. 6 is thinner than the other samples No. 1 to 5, 7, and 8. Therefore, the withstand voltage of sample No. 6 is lower than the withstand voltage of sample No. 9 of the comparative example. On the other hand, the withstand voltages of samples No. 1 to 5, 7, and 8 are greater than or equal to the withstand voltage of sample No. 9 of the comparative example. Therefore, it is preferable that the thickness of the separator is 40 (μm).

Table 2 shows the evaluation results of samples No. 1 to 10 as hybrid electrolytic capacitors. The contents of Table 2 are the same except for the amount of electrolyte retained, ESR, electrolyte evaporation rate, and evaluation results.

As in the case of solid electrolytic capacitors, sample No. For Nos. 1 to 4 and No. 8, the higher the porosity of the separator, the larger the amount of electrolyte retained and the lower the ESR. However, sample no. 5 and 7 are sample nos. Although the porosity was lower than that of No. 4, the fiber diameter was larger and the polymer impregnability was improved, so the amount of electrolyte retained was increased and the ESR was lower. Also, sample No. 6 is sample No. Although the porosity was lower than that of No. 4, the ESR was lower because the thickness was thinner and the conductive path was shorter.

Sample No. which is a comparative example. Based on ESR of 9 and 10, sample No. 9 and 10 of Example. The ESR of 1 to 8 was judged to be pass/fail (OK/NG) (see the judgment results in the table). Sample No. ESR of 1 to 7 is sample no. Since it was lower than the ESR of 9 and 10, it was determined to be OK. Also, sample No. 8 is sample No. The thickness is the same as that of sample No. 9. Although the porosity was higher than that of Sample 9, the ESR was high, so it was determined to be NG.

Therefore, the ESR of samples No. 1 to 7, which have a porosity of 75 to 90%, was suitably reduced. Furthermore, samples No. 1 and 2, which have a porosity of 85 to 90%, had a greater reduction in ESR due to the larger amount of polymer retained.

Furthermore, the evaporation rate of the electrolyte becomes faster as the fiber diameter becomes larger. This is because as the fiber diameter increases, the contact area with the electrolyte decreases, resulting in a decrease in electrolyte retention. As the electrolytic solution evaporates, the acidity increases due to the density of the conductive polymer eluted from the conductive polymer layer into the electrolytic solution, so that the acidification of the separator progresses.

Sample No. which is a comparative example. Based on the transpiration rates of electrolytes No. 9 and No. 10, Sample No. Sample No. 1 to 8 has the largest fiber diameter. The transpiration rate of the electrolyte in Sample No. 5 is as follows. The transpiration rate was higher than that of the electrolyte in No. 9. This is sample No. The fiber diameter of sample no. This is because it is larger than 1-4 or 6-8. On the other hand, other sample No. The transpiration rates of electrolytes Nos. 1 to 4 and 6 to 8 are those of sample No. The transpiration rate was lower than that of electrolytes Nos. 9 and 10. Therefore, by setting the average fiber diameter of the glass fibers to 0.5 to 1 (μm), evaporation of the electrolytic solution was appropriately suppressed and acidification was suppressed. Here, a case where the average value of the fiber diameter is less than 0.5 (μm) is not suitable because the impregnating property of the polymer decreases.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and variations can be made within the scope of the gist of the present invention as described in the claims. Changes are possible.

Claims

It has a capacitor element in which an anode foil and a cathode foil are wound through a separator that holds a conductive polymer layer,
An electrolytic capacitor characterized in that the separator is mainly made of glass fiber with a porosity of 75 to 90%.
The electrolytic capacitor according to claim 1, wherein the glass fiber has a porosity of 85 to 90%.
The separator holds an electrolyte,
The electrolytic capacitor according to claim 1 or 2, wherein the average fiber diameter of the glass fibers is 0.5 to 1 μm.
The electrolytic capacitor according to claim 1 or 2, wherein the glass fiber includes at least one of borosilicate glass, alkali-free borosilicate glass, and high silica glass.
The electrolytic capacitor according to claim 1 or 2, wherein the separator includes at least one of polyester fibers, polyethylene fibers, polypropylene fibers, aramid fibers, acrylic fibers, and cellulose fibers.
The electrolytic capacitor according to claim 1 or 2, wherein the separator contains at least one of polyvinyl alcohol, polyvinyl butyral, polyvinylpyrrolidone, polyurethane, polyvinylidene fluoride, styrene-butadiene rubber, and acrylic resin as a binder.
The electrolytic capacitor according to claim 3, wherein the capacitor element is impregnated with the electrolytic solution containing at least one of ethylene glycol, γ-butyrolactone, and sulfolane.
a step of winding an anode foil and a cathode foil through a separator to produce a capacitor element;
immersing the capacitor element in a conductive polymer dispersion or solution;
and drying the capacitor element,
A method for producing an electrolytic capacitor, wherein the separator is mainly made of glass fiber with a porosity of 75 to 90%.
The method for manufacturing an electrolytic capacitor according to claim 8, wherein the glass fiber has a porosity of 85 to 90%.
further comprising the step of immersing the capacitor element in an electrolytic solution,
10. The method for manufacturing an electrolytic capacitor according to claim 8, wherein the average fiber diameter of the glass fibers is 0.5 to 1 μm.
The method for manufacturing an electrolytic capacitor according to claim 8 or 9, wherein the glass fiber includes at least one of borosilicate glass, alkali-free borosilicate glass, and high silica glass.
The method for manufacturing an electrolytic capacitor according to claim 8 or 9, wherein the separator contains at least one of polyester fibers, polyethylene fibers, polypropylene fibers, aramid fibers, acrylic fibers, and cellulose fibers.
10. The electrolytic capacitor according to claim 8, wherein the separator contains at least one of polyvinyl alcohol, polyvinyl butyral, polyvinylpyrrolidone, polyurethane, polyvinylidene fluoride, styrene-butadiene rubber, and acrylic resin as a binder. Production method.
11. The method for producing an electrolytic capacitor according to claim 10, wherein the capacitor element is impregnated with the electrolyte solution containing at least one of ethylene glycol, γ-butyrolactone, and sulfolane.