WO2025028070A1 - 電解コンデンサ、電解コンデンサの製造方法、および電解コンデンサ用のシート - Google Patents

電解コンデンサ、電解コンデンサの製造方法、および電解コンデンサ用のシート Download PDF

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WO2025028070A1
WO2025028070A1 PCT/JP2024/022730 JP2024022730W WO2025028070A1 WO 2025028070 A1 WO2025028070 A1 WO 2025028070A1 JP 2024022730 W JP2024022730 W JP 2024022730W WO 2025028070 A1 WO2025028070 A1 WO 2025028070A1
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Prior art keywords
sheet
conductive polymer
electrolytic capacitor
polymer layer
separator
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English (en)
French (fr)
Japanese (ja)
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由起也 下山
瞬平 松下
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Panasonic Intellectual Property Management Co Ltd
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Panasonic Intellectual Property Management Co Ltd
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Priority to CN202480047638.2A priority Critical patent/CN121532844A/zh
Priority to JP2025537731A priority patent/JPWO2025028070A1/ja
Publication of WO2025028070A1 publication Critical patent/WO2025028070A1/ja
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/004—Details
    • H01G9/02—Diaphragms; Separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/004—Details
    • H01G9/022—Electrolytes; Absorbents
    • H01G9/025—Solid electrolytes
    • H01G9/028—Organic semiconducting electrolytes, e.g. TCNQ
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/004—Details
    • H01G9/04—Electrodes or formation of dielectric layers thereon
    • H01G9/042—Electrodes or formation of dielectric layers thereon characterised by the material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/004—Details
    • H01G9/04—Electrodes or formation of dielectric layers thereon
    • H01G9/048—Electrodes or formation of dielectric layers thereon characterised by their structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/145—Liquid electrolytic capacitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/15—Solid electrolytic capacitors

Definitions

  • This disclosure relates to electrolytic capacitors, methods for manufacturing electrolytic capacitors, and sheets for electrolytic capacitors.
  • a known electrolytic capacitor is one that includes a wound body of an anode foil, a separator, and a cathode foil.
  • One example of such an electrolytic capacitor includes a conductive polymer layer disposed in the wound body.
  • the conductive polymer layer can be formed by impregnating the wound body with a dispersion liquid that contains a conductive polymer.
  • Various proposals have been made in the past regarding electrolytic capacitors that include a conductive polymer layer.
  • Claim 1 of Patent Document 1 JP Patent Publication No. 2019-516241 describes a "capacitor including a processing element, the processing element including: an anode including a dielectric on a surface and an anode conductive polymer layer on the surface of the dielectric; a cathode including a cathode conductive polymer layer; a conductive separator between the anode and the cathode; an anode lead in electrical contact with the anode; and a cathode lead in electrical contact with the cathode.”
  • Claim 1 of Patent Document 2 (WO 2021/125182) describes a hybrid electrolytic capacitor comprising: a cathode having a cathode substrate made of a valve metal, an oxide layer made of an oxide of the valve metal provided on the surface of the cathode substrate, an inorganic conductive layer containing an inorganic conductive material provided on the surface of the oxide layer, and an organic conductive layer containing a conductive polymer provided on the surface of the inorganic conductive layer; an anode having an anode substrate made of a valve metal, and a dielectric layer made of an oxide of the valve metal constituting the anode substrate provided on the surface of the anode substrate; a solid electrolyte layer provided between the organic conductive layer of the cathode and the dielectric layer of the anode and containing conductive polymer particles in contact with them, and an electrolyte filled between the conductive polymer particles in the solid electrolyte layer.
  • Patent Document 3 JP Patent Publication 2018-110233 A describes a solid electrolytic capacitor comprising: a capacitor element formed by opposing an anode foil and a cathode foil with a separator interposed therebetween; a solid electrolyte layer formed within the capacitor element and made of a conductive polymer; and an electrolyte solution containing a tetravalent or higher sugar alcohol derivative, the electrolyte solution being filled in voids within the capacitor element in which the solid electrolyte layer is formed.
  • the laminate includes an anode foil having a dielectric layer on its surface, a cathode foil, and a sheet disposed between the anode foil and the cathode foil.
  • the sheet includes a separator and a first conductive polymer layer formed in the voids of the separator.
  • the electrical resistivity in the thickness direction of the sheet is 300 k ⁇ cm or less.
  • the air flow resistance of the sheet measured by an air flow tester is 0.40 kPa ⁇ s/m or more and 0.60 kPa ⁇ s/m or less.
  • a sheet for an electrolytic capacitor comprising a capacitor element and a liquid component impregnated into the capacitor element.
  • the sheet comprises a separator and a conductive polymer layer formed in the voids of the separator.
  • the electrical resistivity in the thickness direction of the sheet is 300 k ⁇ cm or less.
  • the air flow resistance of the sheet measured by an air flow tester is 0.40 kPa ⁇ S/m or more and 0.60 kPa ⁇ S/m or less.
  • the manufacturing method includes a preparation step of preparing an anode foil having a dielectric layer on its surface, a sheet formation step of forming a sheet including a separator and a first conductive polymer layer formed in the voids of the separator, a laminate formation step of forming a laminate by stacking the anode foil, the cathode foil, and the sheet so that the sheet is disposed between the anode foil and the cathode foil, and an impregnation step of impregnating the laminate with a liquid component.
  • the sheet formation step includes a first coating liquid application step of applying a first coating liquid containing a first conductive polymer and a first liquid medium into the voids of the separator, and a first liquid medium removal step of forming the sheet by removing at least a part of the first liquid medium from the first coating liquid.
  • the electrical resistivity in the thickness direction of the sheet is 300 k ⁇ cm or less.
  • the airflow resistance of the sheet measured using a breathability tester is 0.40 kPa ⁇ s/m or more and 0.60 kPa ⁇ s/m or less.
  • an electrolytic capacitor containing a liquid component and a conductive polymer layer and having a low ESR can be obtained.
  • FIG. 1 is a side view illustrating a schematic diagram of an example of an electrolytic capacitor according to an embodiment of the present disclosure.
  • FIG. 2 is an exploded perspective view illustrating a schematic diagram of an example of a capacitor element according to an embodiment of the present disclosure.
  • the dispersion liquid containing the conductive polymer has a high viscosity, even if the dispersion liquid is impregnated into the wound body, it may not be possible to form a sufficient conductive polymer layer inside the wound body. Insufficient formation of the conductive polymer layer can cause an increase in equivalent series resistance (ESR).
  • ESR equivalent series resistance
  • This disclosure provides an electrolytic capacitor that contains a liquid component and a conductive polymer layer and has a low ESR.
  • the manufacturing method according to this embodiment may be referred to as "manufacturing method (M)" below.
  • the manufacturing method (M) of the electrolytic capacitor includes a preparation step, a sheet forming step, a laminate forming step, and an impregnation step.
  • the sheet forming step, the laminate forming step, and the impregnation step are performed in this order.
  • the preparation step is performed before the laminate forming step. Each step will be described later.
  • manufacturing method (M) uses a sheet whose electrical resistivity and airflow resistance are within a specified range. This results in an electrolytic capacitor with low ESR and leakage current.
  • the preparation step is a step of preparing an anode foil having a dielectric layer on its surface.
  • the anode foil having a dielectric layer on its surface may be a commercially available product, or may be formed by forming a dielectric layer on the surface of a metal foil (anode foil).
  • the dielectric layer may be formed by a known method. For example, the dielectric layer may be formed by oxidizing the surface of the metal foil (anode foil).
  • the sheet forming step is a step of forming a sheet including a separator and a first conductive polymer layer formed in the voids of the separator.
  • the sheet formed by the sheet forming step may be referred to as a "sheet (S)".
  • the sheet forming step includes a first coating liquid applying step of applying a first coating liquid containing a first conductive polymer and a first liquid medium into the voids of the separator, and a first liquid medium removing step of forming a sheet (S) by removing at least a part of the first liquid medium from the first coating liquid.
  • the first conductive polymer may be dispersed in the first coating liquid in the form of particles. Examples of conductive polymers will be described later.
  • the first liquid medium is not particularly limited, and any liquid medium that can be used to form a polymer layer can be used.
  • the first liquid medium include water, organic solvents (e.g., alcohol), and mixtures thereof.
  • the first liquid medium may contain water and an organic compound that does not boil at 100°C under 1 atmosphere (101,325 Pa).
  • organic compound may be referred to as "organic compound (C).”
  • Organic compound (C) may be one type of compound or may be composed of multiple types of compounds.
  • the method of applying the first coating liquid is not limited, and may be applied by a known method.
  • a coater may be used, the first coating liquid may be sprayed, or the object to be coated may be immersed in the first coating liquid.
  • methods using a coater include gravure coating and die coating.
  • the coating liquid is first applied to a transfer member such as a gravure roll, and then excess coating liquid is removed from the transfer member.
  • the coating liquid applied to the transfer member is transferred to a specified member (anode foil, cathode foil, or separator), so that a layer of coating liquid with a uniform thickness can be applied to the member.
  • the viscosity of the coating liquid may be, for example, 10 mPa ⁇ s or more (for example, 100 mPa ⁇ s or more) and 200 mPa ⁇ s or less.
  • the coating liquid is easy to apply to the anode foil, cathode foil, and separator, and is easy to impregnate the separator.
  • the viscosity of the coating liquid is measured at room temperature (20°C) using a vibration viscometer (e.g., VM-100A, manufactured by Sekonic Corporation).
  • the method of removing at least a part of the first liquid medium from the first coating liquid is not particularly limited, and can be performed by heating or the like.
  • heating may be performed so that the organic compound (C) remains in the first conductive polymer layer.
  • the first coating liquid contains an organic compound (C) and water (liquid medium)
  • the heating temperature may be 100°C or higher, 120°C or higher, or 140°C or higher, and may be 200°C or lower, or 160°C or lower.
  • the heating temperature may be in the range of 100°C to 200°C. There is no particular limit to the heating time, and it may be a time that allows a part of the first liquid medium to be appropriately removed. An example of the heating time is in the range of 5 to 60 minutes.
  • the organic compound (C) in the first conductive polymer layer By leaving the organic compound (C) in the first conductive polymer layer, it is possible to reduce the shrinkage of the conductive polymer layer when the first liquid medium is removed from the first coating liquid. As a result, in the subsequent impregnation step, the liquid component (e.g., electrolyte) can easily penetrate into the first conductive polymer layer. As a result, the liquid component's function of forming a dielectric layer (oxide film) can be fully exerted, and leakage current is reduced.
  • the liquid component e.g., electrolyte
  • the water content in the first coating liquid is 40 mass % or more (e.g., 50 mass % or more), and the first liquid medium of the applied first coating liquid is removed so that the mass of the organic compound (C) in the first conductive polymer layer is greater than the mass of water in the first conductive polymer layer. If the water content in the first coating liquid is high, the electrolyte solution is more likely to be impregnated into the first conductive polymer layer after the first conductive polymer layer is formed.
  • the electrical resistivity in the thickness direction of the sheet (S) (hereinafter, sometimes referred to as "electrical resistivity Re") is 300 k ⁇ cm or less. By setting the electrical resistivity Re to 300 k ⁇ cm or less, the ESR of the electrolytic capacitor can be reduced.
  • the electrical resistivity Re may be 200 k ⁇ cm or less.
  • the electrical resistivity Re may be 100 k ⁇ cm or more, or 150 k ⁇ cm or more.
  • the electrical resistivity Re can be changed by the concentration of the first conductive polymer in the first coating liquid, the amount of the first coating liquid applied in the voids of the separator, etc. By increasing the amount of the first conductive polymer placed in the voids of the separator, the electrical resistivity Re can be reduced.
  • the electrical resistivity Re can be measured by the following method. First, a sheet (S) cut to a predetermined size (2.5 cm x 3.5 cm) is sandwiched between two aluminum plates (size: 2 cm x 3 cm, area Ss: 6 cm2). Furthermore, the aluminum plate sandwiching the sheet (S) is sandwiched between two glass plates from the outside, and the two glass plates are pressed with clips to bring the two aluminum plates and the sheet (S) into close contact. Thereafter, the electrical resistance Rs between the two aluminum plates is measured. In addition, the average thickness Ta of the measured sheet (S) is measured. Then, the electrical resistivity Re was calculated from the area Ss, the measured electrical resistance Rs, and the average thickness Ta. The average thickness Ta of the sheet (S) is measured by the method described below.
  • airflow resistance of the sheet (S) measured by the air permeability tester (hereinafter, sometimes referred to as "airflow resistance Rg") is 0.40 kPa ⁇ s/m or more, and may be 0.45 kPa ⁇ s/m or more, or 0.49 kPa ⁇ s/m or more.
  • the airflow resistance Rg may be 0.60 kPa ⁇ s/m or less, 0.58 kPa ⁇ s/m or less, or 0.49 kPa ⁇ s/m or less.
  • the smaller the airflow resistance Rg the easier it is for gas to pass through the sheet (S).
  • the airflow resistance Rg can be measured by the method described in the examples.
  • the electrical resistivity of the sheet (S) can be increased, making it possible to reduce the ESR of the electrolytic capacitor.
  • the airflow resistance Rg 0.60 kPa ⁇ s/m or less, the amount of liquid component (LC) described below that is retained in the sheet (S) can be increased, improving the repair function of the dielectric layer by the liquid component (LC). As a result, the leakage current of the electrolytic capacitor can be reduced.
  • the airflow resistance Rg can be changed by the concentration of the first conductive polymer in the first coating liquid, the amount of the first coating liquid applied in the gaps of the separator, etc. By reducing the amount of the first conductive polymer placed in the gaps of the separator, the airflow resistance Rg can be reduced.
  • the ratio (Vd/Vs) of the volume Vd of the first coating liquid impregnated into the separator to the volume Vs of the separator voids may be 0.95 or more.
  • a conductive polymer layer can be formed uniformly in the separator voids.
  • the ratio Vd/Vs is 1.0 or less.
  • the volume Vs of the separator voids can be calculated by multiplying the value obtained by subtracting the nominal density of the separator from the density of the separator material (separator material density - nominal density) by the volume of the separator (separator area x average thickness of the separator).
  • the average thickness of the separator can be measured by a method similar to the method for measuring the average thickness Ta of the sheet, which will be described later.
  • the surface density of the first conductive polymer layer may be 0.05 mg/cm2 or more , 0.1 mg/ cm2 or more, or 0.3 mg/cm2 or more , and may be 1.0 mg/cm2 or less , or 0.5 mg/cm2 or less .
  • the surface density of the first conductive polymer layer may be 0.1 mg/ cm2 or more and 1.0 mg/ cm2 or less. According to this configuration, an electrolytic capacitor with a particularly low ESR is obtained.
  • the surface density means the mass per unit area.
  • the surface density of the first conductive polymer layer can be controlled by the concentration of the first conductive polymer in the first coating liquid or the coating amount of the first coating liquid.
  • the surface density of the first conductive polymer layer can be determined by the following method. First, five samples are prepared by cutting out a specified area from the separator before the first conductive polymer layer is formed, and the mass of the five samples is measured. In addition, five samples are prepared by cutting out the separator on which the first conductive polymer layer is formed, and the mass of the samples is measured. The surface density of the first conductive polymer layer is determined by using the difference between the total mass of the five samples after the first conductive polymer layer is formed and the total mass of the five samples before the first conductive polymer layer is formed, and the specified area. The surface density of the second conductive polymer layer, which will be described later, can also be determined by a similar method.
  • the average thickness of the sheet (S) (hereinafter sometimes referred to as "average thickness Ta") may be 20 ⁇ m or more, or 40 ⁇ m or more, and may be 70 ⁇ m or less, or 60 ⁇ m or less.
  • average thickness Ta By setting the average thickness Ta to 20 ⁇ m or more and 70 ⁇ m or less, a gap between the electrodes is ensured, and the penetration of the electrolyte between the electrodes can be promoted.
  • the average thickness Ta of the sheet (S) can be measured by the following method. First, the film thickness is measured at any 10 points on the sheet (S) using a film thickness measuring device (such as a micrometer). Then, the average thickness Ta is obtained by taking the arithmetic average of the 10 measured values.
  • the laminate formation step is a step of forming a laminate by laminating an anode foil, a cathode foil, and a sheet (S) such that the sheet (S) is disposed between the anode foil and the cathode foil.
  • the method for forming the laminate is not particularly limited, and the laminate may be formed by a known method.
  • the laminate may be a wound body.
  • the wound body may be formed by winding the anode foil, the cathode foil, and the sheet (S) such that the sheet (S) is disposed between the anode foil and the cathode foil.
  • the anode foil, the cathode foil, and the sheet (S) are stacked in the radial direction of the wound body.
  • the laminate may be formed by stacking a flat anode foil, a flat cathode foil, and a flat sheet (S) in one direction.
  • a laminate may be formed by stacking a plurality of anode foils, a plurality of cathode foils, and a plurality of sheets (S) in one direction.
  • the anode foils and cathode foils are arranged alternately, and the sheet (S) is arranged between the anode foils and the cathode foils.
  • the impregnation step is a step of impregnating the laminate with a liquid component.
  • the liquid component may be referred to as a "liquid component (LC)".
  • the method of impregnating the laminate with the liquid component (LC) is not limited.
  • the laminate may be impregnated with the liquid component (LC) by immersing at least a part of the laminate in the liquid component (LC).
  • the liquid component (LC) may be an electrolyte solution.
  • a capacitor element is obtained. Thereafter, other processes may be carried out as necessary. For example, a process may be carried out in which the capacitor element impregnated with the liquid component (LC) is enclosed in an exterior body.
  • LC liquid component
  • the manufacturing method (M) may further include a polymer layer forming step of forming a second conductive polymer layer on the surface of the dielectric layer before the laminate forming step.
  • the polymer layer forming step includes a second coating liquid applying step of applying a second coating liquid containing a second conductive polymer and a second liquid medium to the surface of the dielectric layer (the dielectric layer on the surface of the anode foil), and a second liquid medium removing step of removing at least a part of the second liquid medium from the second coating liquid to form a second conductive polymer layer.
  • the first conductive polymer and the second conductive polymer may be the same or different.
  • the first liquid medium and the second liquid medium may be the same or different.
  • the first coating liquid and the second coating liquid may be the same or different.
  • the surface density of the second conductive polymer layer may be within the range exemplified for the surface density of the first conductive polymer layer.
  • the method of applying the second coating liquid to the surface of the dielectric layer is not particularly limited, and any of the methods exemplified in the first coating liquid application step may be applied.
  • the method of removing at least a portion of the second liquid medium from the second coating liquid is not particularly limited, and any of the methods exemplified in the first liquid medium removal step may be applied.
  • the manufacturing method (M) may include a liquid application step and a removal step, in this order, after the laminate formation step and before the impregnation step.
  • the liquid application step is a step of impregnating the laminate with a liquid (hereinafter, sometimes referred to as "liquid (L)").
  • the removal step is a step of removing at least a portion of the liquid (L) impregnated into the laminate.
  • the liquid (L) may be a liquid containing water as a main component and an organic compound (C) that does not boil at 100°C under 1 atmosphere.
  • the removal step may be a step of removing a portion of the liquid (L) impregnated into the laminate so that the mass of the organic compound (C) in the laminate is greater than the mass of water in the laminate.
  • the liquid (L) used in the liquid application step may be the first coating liquid used in the sheet formation step from which the first conductive polymer component has been removed.
  • the impregnation with the liquid (L) in the liquid application step may be performed by the method exemplified for the first coating liquid application step in the sheet formation step.
  • the removal of the liquid (L) in the removal step may be performed by the method exemplified for the first liquid medium removal step in the sheet formation step.
  • the cathode foil may have an inorganic layer on its surface, and the first conductive polymer layer may be in close contact with the inorganic layer.
  • the cathode foil is made of only a metal foil (e.g., aluminum foil), an oxide layer forms on the surface of the metal foil, and capacitance also occurs in the cathode foil.
  • a metal foil e.g., aluminum foil
  • capacitance also occurs in the cathode foil.
  • the capacitance of the anode foil and the capacitance of the cathode foil are combined, which can cause a problem of a decrease in the capacitance of the entire capacitor.
  • an inorganic layer etc. it is possible to prevent such a problem from occurring. In other words, by forming an inorganic layer, it is possible to draw out only the capacitance of the anode foil.
  • the ESR will be high.
  • Inorganic layers tend to repel water, so in the conventional method of forming a conductive polymer layer by impregnating a laminate (capacitor element) with an aqueous dispersion of a conductive polymer, the conductive polymer has difficulty entering between the inorganic layer of the cathode foil and the anode foil in the laminate, making it impossible to form a uniform conductive polymer layer on the separator placed between the cathode foil and anode foil, resulting in an increase in ESR.
  • manufacturing method (M) a laminate (capacitor element) is formed using a separator on which a first conductive polymer layer has already been formed. This makes it possible to prevent the first conductive polymer from becoming unevenly distributed within the separator.
  • electrolytic capacitor The electrolytic capacitor according to this embodiment may be referred to as "electrolytic capacitor (E)" below.
  • the electrolytic capacitor (E) may be manufactured by the manufacturing method (M) described above.
  • the matters described for the manufacturing method (M) may be applied to the electrolytic capacitor (E), and therefore, duplicated explanations may be omitted.
  • the matters described for the electrolytic capacitor (E) may also be applied to the manufacturing method (M).
  • the electrolytic capacitor (E) includes a laminate and a liquid component impregnated in the laminate.
  • the laminate includes an anode foil having a dielectric layer on its surface, a cathode foil, and a sheet (sheet (S)) disposed between the anode foil and the cathode foil.
  • the sheet includes a separator and a first conductive polymer layer formed in the voids of the separator.
  • the electrical resistivity Re of the sheet (S) in the thickness direction is 300 k ⁇ cm or less.
  • the air flow resistance Rg of the sheet measured by an air flow tester is 0.40 kPa ⁇ s/m or more and 0.60 kPa ⁇ s/m or less.
  • the electrolytic capacitor (E) provides the effects described in the manufacturing method (M).
  • the configuration of the electrolytic capacitor (E) makes it possible to reduce the ESR.
  • the surface density of the first conductive polymer layer of the electrolytic capacitor (E) may be 0.1 mg/cm 2 or more and 1.0 mg/cm 2 or less.
  • the average thickness Ta of the sheet (S) of the electrolytic capacitor (E) may be 20 ⁇ m or more and 70 ⁇ m or less.
  • the electrolytic capacitor (E) may further include a second conductive polymer layer formed on the dielectric layer on the surface of the anode foil.
  • the cathode foil may have an inorganic layer on its surface, and the first conductive polymer layer may be in close contact with the inorganic layer.
  • the laminate may be a wound body, or it may be a laminate other than a wound body.
  • the sheet according to this embodiment is the sheet (S) described above.
  • the sheet (S) can be formed by the sheet forming process described above. In the description of the manufacturing method (M), the matters described about the sheet forming process and the sheet (S) can be applied to the sheet (S), so that duplicated descriptions may be omitted.
  • the sheet (S) is disposed at a position where a separator is disposed in an electrolytic capacitor, and can be used as a substitute for a separator.
  • the sheet (S) is a sheet used in an electrolytic capacitor that includes a capacitor element and a liquid component impregnated into the capacitor element.
  • the sheet (S) includes a separator and a conductive polymer layer (first conductive polymer layer) formed in the voids of the separator.
  • the electrical resistivity Re of the sheet (S) in the thickness direction is 300 k ⁇ cm or less.
  • the air flow resistance Rg of the sheet (S) measured by an air flow tester is 0.40 kPa ⁇ S/m or more and 0.60 kPa ⁇ S/m or less.
  • the surface density of the conductive polymer layer (first conductive polymer layer) formed in the voids of the sheet (S) may be 0.1 mg/cm 2 or more and 1.0 mg/cm 2 or less.
  • the average thickness of the sheet (S) may be 20 ⁇ m or more and 70 ⁇ m or less.
  • the term "conductive polymer component" may be used.
  • the conductive polymer component is made of a conductive polymer.
  • the conductive polymer component is made of a conductive polymer and a dopant.
  • the coating liquids (first coating liquid, second coating liquid) used in the polymer layer forming step may contain a conductive polymer and water.
  • the conductive polymer (conductive polymer component) may be contained in the coating liquid in the form of particles.
  • the coating liquid may be an aqueous dispersion of the conductive polymer (conductive polymer component).
  • the coating liquid may contain other components (e.g., organic compound (C)).
  • the organic compound (C) may contain at least one selected from the group consisting of polyhydric alcohols, sulfolane, ⁇ -butyrolactone, and boric acid esters, or may be at least one of the above.
  • the organic compound (C) may contain at least one selected from the group consisting of glycols, glycerins, sugar alcohols, sulfolane, ⁇ -butyrolactone, and boric acid esters, or may be at least one of the above.
  • polyhydric alcohols examples include glycols, glycerins, and sugar alcohols.
  • glycols include ethylene glycol, diethylene glycol, triethylene glycol, polyalkylene glycols (e.g., polyethylene glycol), polyoxyethylene polyoxypropylene glycol (ethylene oxide-propylene oxide copolymer), and the like.
  • glycerins include glycerin and polyglycerin.
  • sugar alcohols include mannitol, xylitol, sorbitol, erythritol, and pentaerythritol, and the like.
  • Examples of conductive polymers include polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, and derivatives thereof.
  • the derivatives include polymers having polypyrrole, polythiophene, polyfuran, polyaniline, and polyacetylene as the basic skeleton.
  • a derivative of polythiophene includes poly(3,4-ethylenedioxythiophene).
  • These conductive polymers may be used alone or in combination.
  • the conductive polymer may also be a copolymer of two or more monomers.
  • the weight-average molecular weight of the conductive polymer is not particularly limited and may be in the range of 1,000 to 100,000, for example.
  • a preferred example of a conductive polymer is poly(3,4-ethylenedioxythiophene) (PEDOT).
  • the conductive polymer may be doped with a dopant. From the viewpoint of suppressing dedoping from the conductive polymer, it is preferable to use a polymer dopant as the dopant.
  • polymer dopants include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polyacryl sulfonic acid, polymethacryl sulfonic acid, poly(2-acrylamido-2-methylpropane sulfonic acid), polyisoprene sulfonic acid, polyacrylic acid, and the like. These may be used alone or in combination of two or more. At least a portion of these may be added in the form of a salt.
  • a preferred example of a dopant is polystyrene sulfonic acid (PSS).
  • the dopant may be polystyrenesulfonic acid
  • the conductive polymer may be poly(3,4-ethylenedioxythiophene). That is, the conductive polymer component may be poly(3,4-ethylenedioxythiophene) doped with polystyrenesulfonic acid.
  • the pH of the coating liquid is preferably less than 7.0 in order to suppress dedoping of the dopant, and may be 6.0 or less or 5.0 or less.
  • the pH of the coating liquid may be 1.0 or more, or 2.0 or more.
  • the water content in the coating liquid may be 40% by mass or more, 50% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more.
  • the water content may be 98% by mass or less, 95% by mass or less, 90% by mass or less, or 80% by mass or less.
  • the content of the organic compound (C) in the coating liquid may be 1.0 mass% or more, 3.0 mass% or more, 5.0 mass% or more, or 10 mass% or more. It may be 30 mass% or less, 20 mass% or less, 15 mass% or less, or 10 mass% or less.
  • the content of the conductive polymer component in the coating liquid may be 0.5 mass% or more, or 1.0 mass% or more, and may be 4.0 mass% or less, 3.0 mass% or less, or 2.0 mass% or less.
  • the content may be in the range of 0.5 to 4.0 mass% or 1.0 to 4.0 mass%. In any of these ranges, the upper limit may be 3.0 mass% or 2.0 mass%.
  • the content is preferably in the range of 1.0 to 3.0%.
  • the mass of the dopant is included in the mass of the conductive polymer component.
  • the mass of the dopant contained in the coating liquid there are no particular limitations on the mass of the dopant contained in the coating liquid, and it may be in the range of 0.1 to 5 times (e.g., 0.5 to 3 times) the mass of the conductive polymer contained in the coating liquid.
  • the water content: organic compound (C) content: conductive polymer component content may be 40-98:1.0-59.5:0.5-4.0, or the water content: organic compound (C) content: conductive polymer component content may be 69.5-98:1.0-30:0.5-4.0.
  • liquid component (LC) examples of the liquid component (LC) used in the impregnation step include a non-aqueous solvent and an electrolytic solution.
  • the electrolytic solution may be an electrolytic solution containing a non-aqueous solvent and a solute dissolved in the non-aqueous solvent.
  • the liquid component (LC) may be a component that is liquid at room temperature (25° C.) or a component that is liquid at the temperature when the electrolytic capacitor is used.
  • the non-aqueous solvent used in the liquid component (LC) may be an organic solvent, an ionic liquid, or a protic solvent.
  • non-aqueous solvents include polyhydric alcohols such as ethylene glycol and propylene glycol, cyclic sulfones such as sulfolane (SL), lactones such as ⁇ -butyrolactone ( ⁇ BL), amides such as N-methylacetamide, N,N-dimethylformamide, and N-methyl-2-pyrrolidone, esters such as methyl acetate, carbonate compounds such as propylene carbonate, ethers such as 1,4-dioxane, ketones such as methyl ethyl ketone, and formaldehyde.
  • polyhydric alcohols such as ethylene glycol and propylene glycol
  • cyclic sulfones such as sulfolane (SL)
  • lactones such as ⁇ -butyrolactone ( ⁇ BL)
  • a polymer solvent may be used as the non-aqueous solvent.
  • polymer solvents include polyalkylene glycol, derivatives of polyalkylene glycol, and compounds in which at least one hydroxyl group in a polyhydric alcohol is replaced with polyalkylene glycol (including derivatives).
  • examples of polymer solvents include polyethylene glycol (PEG), polyethylene glycol glyceryl ether, polyethylene glycol diglyceryl ether, polyethylene glycol sorbitol ether, polypropylene glycol, polypropylene glycol glyceryl ether, polypropylene glycol diglyceryl ether, polypropylene glycol sorbitol ether, and polybutylene glycol.
  • polymer solvents further include ethylene glycol-propylene glycol copolymers, ethylene glycol-butylene glycol copolymers, and propylene glycol-butylene glycol copolymers.
  • the non-aqueous solvent may be used alone or in a mixture of two or more.
  • the liquid component (LC) may include a non-aqueous solvent and a base component (base) dissolved in the non-aqueous solvent.
  • the liquid component (LC) may also include a non-aqueous solvent and a base component and/or an acid component (acid) dissolved in the non-aqueous solvent.
  • polycarboxylic acids and monocarboxylic acids can be used as the acid component.
  • the polycarboxylic acids include aliphatic polycarboxylic acids (saturated polycarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,6-decanedicarboxylic acid, 5,6-decanedicarboxylic acid; unsaturated polycarboxylic acids such as maleic acid, fumaric acid, itaconic acid), aromatic polycarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid), and alicyclic polycarboxylic acids (cyclohexane-1,2-dicarboxylic acid, cyclohexene-1,2-dicarboxylic acid, etc.).
  • saturated polycarboxylic acids such as ox
  • Examples of the monocarboxylic acids include aliphatic monocarboxylic acids (1 to 30 carbon atoms) ([saturated monocarboxylic acids, such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, lauric acid, myristic acid, stearic acid, behenic acid]; [unsaturated monocarboxylic acids, such as acrylic acid, methacrylic acid, oleic acid]), aromatic monocarboxylic acids (such as benzoic acid, cinnamic acid, naphthoic acid), and oxycarboxylic acids (such as salicylic acid, mandelic acid, resorcylic acid).
  • saturated monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid
  • maleic acid, phthalic acid, benzoic acid, pyromellitic acid, and resorcylic acid are thermally stable and are preferably used.
  • Inorganic acids may be used as the acid component.
  • inorganic acids include phosphoric acid, phosphorous acid, hypophosphorous acid, alkyl phosphate esters, boric acid, boric fluoride, tetrafluoroboric acid, hexafluorophosphoric acid, benzenesulfonic acid, and naphthalenesulfonic acid.
  • composite compounds of organic acids and inorganic acids may be used as the acid component. Examples of such composite compounds include borodiglycolic acid, borodioxalic acid, and borodisalicylic acid.
  • the base component may be a compound having an alkyl-substituted amidine group, such as an imidazole compound, a benzimidazole compound, or an alicyclic amidine compound (pyrimidine compound, imidazoline compound).
  • an imidazole compound such as an imidazole compound, a benzimidazole compound, or an alicyclic amidine compound (pyrimidine compound, imidazoline compound).
  • 1,8-diazabicyclo[5,4,0]undecene-7, 1,5-diazabicyclo[4,3,0]nonene-5 1,2-dimethylimidazolinium, 1,2,4-trimethylimidazoline, 1-methyl-2-ethyl-imidazoline, 1,4-dimethyl-2-ethylimidazoline, 1-methyl-2-heptyl imidazoline, 1-methyl-2-(3'heptyl)imidazoline, 1-methyl-2-dodecyl imidazoline, 1,2-di
  • the base component may be a quaternary salt of a compound having an alkyl-substituted amidine group.
  • base components include imidazole compounds, benzimidazole compounds, and alicyclic amidine compounds (pyrimidine compounds, imidazoline compounds) that are quaternized with an alkyl group or arylalkyl group having 1 to 11 carbon atoms.
  • a tertiary amine may be used as the base component.
  • tertiary amines include trialkylamines (trimethylamine, dimethylethylamine, methyldiethylamine, triethylamine, dimethyl-n-propylamine, dimethylisopropylamine, methylethyl-n-propylamine, methylethylisopropylamine, diethyl-n-propylamine, diethylisopropylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, tri-tert-butylamine, etc.), and phenyl group-containing amines (dimethylphenylamine, methylethylphenylamine, diethylphenylamine, etc.).
  • trialkylamines are preferred in terms of increasing electrical conductivity, and it is more preferred to include at least one selected from the group consisting of trimethylamine, dimethylethylamine, methyldiethylamine, and triethylamine.
  • secondary amines such as dialkylamines, primary amines such as monoalkylamines, and ammonia may be used as the base component.
  • the liquid component (LC) may contain a salt of an acid component and a base component.
  • the salt may be an inorganic salt and/or an organic salt.
  • An organic salt is a salt in which at least one of the anion and the cation contains an organic substance. Examples of organic salts that may be used include trimethylamine maleate, triethylamine borodisalicylate, ethyldimethylamine phthalate, mono 1,2,3,4-tetramethylimidazolinium phthalate, and mono 1,3-dimethyl-2-ethylimidazolinium phthalate.
  • the pH of the liquid component (LC) may be less than 7.0 or less than 5.0, or may be greater than 1.0, or greater than 2.0.
  • the pH may be greater than 1.0 and less than 7.0 (e.g., in the range of 2.0 to 5.0).
  • the liquid component (LC) preferably contains a protic solvent. By using a protic solvent, it is possible to particularly swell the conductive polymer layer. In addition to the protic solvent, the liquid component (LC) may contain a solvent other than the protic solvent.
  • the protic solvent may include at least one selected from the group consisting of glycols, glycerin, polyglycerin, and sugar alcohols, or may be at least one of the above.
  • the protic solvent may be composed of only one type of compound, or may include multiple types of compounds.
  • the organic compound (C) and the liquid component (LC) may contain the same compound.
  • they may contain the same polyhydric alcohol, the same glycols (such as ethylene glycol), or the same sugar alcohol.
  • the liquid (L) may be a liquid containing the above-mentioned organic compound (C) and water. In this case, it is preferable to impregnate the laminate with the liquid (L) and then remove water from the laminate under conditions in which the organic compound (C) remains in the laminate.
  • the organic compound (C) may be at least one selected from the group consisting of mannitol, mannitol derivatives, xylitol, and xylitol derivatives.
  • the liquid (L) may contain at least one substance (hereinafter, sometimes referred to as "substance X") selected from the group consisting of sugar, sugar alcohol, epoxy resin, and polyvinyl alcohol.
  • substance X selected from the group consisting of sugar, sugar alcohol, epoxy resin, and polyvinyl alcohol.
  • the sugar alcohol may include at least one selected from the group consisting of mannitol, mannitol derivatives, xylitol, and xylitol derivatives, or may be at least one of the above.
  • the substance X may be at least one selected from the group consisting of mannitol, mannitol derivatives, xylitol, and xylitol derivatives. Mannitol, mannitol derivatives, xylitol, and xylitol derivatives have the effect of adhering the conductive polymer layer and the cathode foil.
  • Examples of mannitol derivatives include compounds in which some of the hydroxyl groups of mannitol are esterified, compounds in which some of the hydroxyl groups of mannitol are etherified, and compounds in which some of the hydroxyl groups of mannitol are anionized to form a salt.
  • Examples of xylitol derivatives include compounds in which some of the hydroxyl groups of xylitol are esterified, compounds in which some of the hydroxyl groups of xylitol are etherified, and compounds in which some of the hydroxyl groups of xylitol are anionized to form a salt.
  • the organic solvent contained in the liquid (L) may contain at least one selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol, or may be at least one of the organic solvents. By containing these in the liquid (L), the electrical conductivity of the conductive polymer layer can be increased.
  • a preferred example of the liquid (L) is a liquid containing xylitol in at least one organic solvent selected from the group consisting of triethylene glycol and polyethylene glycol.
  • anode foil examples include metal foils containing at least one of valve metals such as titanium, tantalum, aluminum, and niobium, and may be metal foils of valve metals (e.g., aluminum foils).
  • the anode foil may contain the valve metal in the form of an alloy containing the valve metal or a compound containing the valve metal.
  • the thickness of the anode foil may be 15 ⁇ m or more and 300 ⁇ m or less.
  • the surface of the anode foil may be roughened by etching or the like.
  • a dielectric layer is formed on the surface of the anode foil.
  • the dielectric layer may be formed by subjecting the anode foil to a chemical conversion treatment.
  • the dielectric layer may contain an oxide of a valve metal (e.g., aluminum oxide).
  • the dielectric layer may be formed of any dielectric other than an oxide of a valve metal as long as it functions as a dielectric.
  • a conductive polymer layer does not need to be formed on the end surface of the anode foil.
  • a dielectric layer is formed on the end surface of the anode foil.
  • the cathode foil includes a metal foil (e.g., aluminum foil).
  • the metal constituting the metal foil may be a valve metal or an alloy containing a valve metal.
  • the surface of the metal foil may be roughened by etching or the like.
  • the thickness of the cathode foil may be 15 ⁇ m or more and 300 ⁇ m or less.
  • a conductive polymer layer may be formed on the surface of the cathode foil by the above-mentioned method.
  • the cathode foil may have an inorganic layer on its surface.
  • the cathode foil having an inorganic layer on its surface may be a commercially available product, or may be formed by forming an inorganic layer on the surface of a metal foil (cathode foil).
  • the inorganic layer may be formed by a known method.
  • the inorganic layer may be formed by a vacuum deposition method or the like.
  • the inorganic layer may be formed by applying a paste containing one selected from the group consisting of carbon (particularly a conductive carbon material), titanium, and nickel onto the metal foil (cathode foil) and then drying it.
  • the amount of the inorganic layer may be in the range of 50 mg/m 2 to 300 mg/m 2 (for example, in the range of 70 mg/m 2 to 200 mg/m 2 ).
  • Examples of carbon (particularly a conductive carbon material) contained in the inorganic layer include graphite, hard carbon, soft carbon, carbon black, and the like.
  • the inorganic layer may be a layer formed by depositing titanium or a layer formed by particles of titanium oxide.
  • the inorganic layer may be a carbon layer.
  • the carbon layer may be a layer containing carbon, and may have a carbon content of 50 mass% or more. In this specification, the term "inorganic layer" may be replaced with "carbon layer.”
  • the cathode foil may include a metal foil, an inorganic layer, and a titanium-containing layer disposed between the inorganic layer and the metal foil.
  • An example of the cathode foil has a laminated structure of inorganic layer/titanium-containing layer/metal foil (e.g., aluminum foil)/titanium-containing layer/inorganic layer.
  • the titanium-containing layer may contain at least one selected from the group consisting of titanium and titanium compounds. Examples of titanium compounds include titanium nitride, titanium oxide, titanium aluminum alloy, titanium carbonate, and the like.
  • the method of forming the titanium-containing layer is not limited, and the layer may be formed by a known method.
  • the titanium-containing layer may be formed by a physical vapor deposition method such as a vacuum deposition method or a sputtering method.
  • the deposition amount of the titanium-containing layer may be in the range of 200 mg/m 2 to 500 mg/m 2 (e.g., in the range of 250 mg/m 2 to 400 mg/m 2 ).
  • the separator may be a porous sheet formed of an insulating material.
  • the porous sheet include woven fabric, nonwoven fabric, and microporous membrane.
  • the thickness of the separator is not particularly limited and may be in the range of 10 to 300 ⁇ m.
  • the material of the separator include cellulose, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, vinylon, nylon, aromatic polyamide, polyimide, polyamideimide, polyetherimide, rayon, and glass.
  • the air permeability resistance of the separator alone (a separator without the first conductive polymer layer) measured by an air permeability tester may be 0.25 kPa ⁇ s/m or more, or 0.30 kPa ⁇ s/m or more, or 0.40 kPa ⁇ s/m or less, or 0.35 kPa ⁇ s/m or less.
  • the laminate and the liquid component (LC) are housed in an exterior body.
  • the exterior body includes a case and/or a sealing resin.
  • the sealing resin may include a thermosetting resin.
  • the thermosetting resin include an epoxy resin, a phenolic resin, a silicone resin, a melamine resin, a urea resin, an alkyd resin, a polyurethane, a polyimide, an unsaturated polyester, and the like.
  • the sealing resin may include a filler, a curing agent, a polymerization initiator, and/or a catalyst, and the like.
  • FIG. 1 is a cross-sectional view showing an example of an electrolytic capacitor 100 according to this embodiment.
  • FIG. 2 is a schematic diagram showing an exploded view of a portion of a capacitor element 10 included in the electrolytic capacitor 100.
  • the electrolytic capacitor 100 comprises a capacitor element 10, a bottomed case 101 that houses the capacitor element 10, a sealing member 102 that closes the opening of the bottomed case 101, a seat plate 103 that covers the sealing member 102, lead wires 104A, 104B that extend from the sealing member 102 and pass through the seat plate 103, and lead tabs 105A, 105B that connect the lead wires to the electrodes of the capacitor element 10.
  • the area near the open end of the bottomed case 101 is drawn inward, and the open end is curled so as to be crimped to the sealing member 102.
  • Capacitor element 10 is, for example, a wound body as shown in FIG. 1.
  • the wound body includes anode foil 11 connected to lead tab 105A, cathode foil 12 connected to lead tab 105B, and sheet 13.
  • Sheet 13 includes a separator and a first conductive polymer layer formed in the gap of the separator.
  • Capacitor element 10 (wound body) includes a conductive polymer layer (not shown).
  • the conductive polymer layer may include an organic compound (C).
  • Electrolytic capacitor 100 includes a liquid component (LC) (e.g., an electrolyte) impregnated in capacitor element 10.
  • LC liquid component
  • the anode foil 11 and the cathode foil 12 are wound with a sheet 13 interposed therebetween.
  • the outermost circumference of the wound body is fixed with a stop tape 14. Note that Figure 2 shows the wound body in a partially unfolded state before the outermost circumference is fixed.
  • An electrolytic capacitor may have at least one capacitor element, but may also have multiple capacitor elements.
  • the number of capacitor elements included in an electrolytic capacitor may be determined according to the application.
  • An electrolytic capacitor comprising a laminate and a liquid component impregnated in the laminate, the laminate includes an anode foil having a dielectric layer on a surface thereof, a cathode foil, and a sheet disposed between the anode foil and the cathode foil, the sheet includes a separator and a first conductive polymer layer formed in voids of the separator;
  • the electrical resistivity in the thickness direction of the sheet is 300 k ⁇ cm or less
  • the electrolytic capacitor has an air permeability resistance of 0.40 kPa ⁇ s/m or more and 0.60 kPa ⁇ s/m or less as measured by a breathability tester.
  • the cathode foil has an inorganic layer on a surface thereof,
  • a sheet for an electrolytic capacitor comprising a capacitor element and a liquid component impregnated in the capacitor element, A separator and a conductive polymer layer formed in a void of the separator,
  • the electrical resistivity in the thickness direction of the sheet is 300 k ⁇ cm or less
  • the sheet for an electrolytic capacitor, wherein the sheet has an air permeability resistance of 0.40 kPa ⁇ S/m or more and 0.60 kPa ⁇ S/m or less as measured by an air permeability tester.
  • a method for manufacturing an electrolytic capacitor comprising the steps of: A preparation step of preparing an anode foil having a dielectric layer on a surface thereof; a sheet forming step of forming a sheet including a separator and a first conductive polymer layer formed in voids of the separator; a laminate formation step of forming a laminate by stacking the anode foil, the cathode foil, and the sheet such that the sheet is disposed between the anode foil and the cathode foil; an impregnation step of impregnating the laminate with a liquid component
  • the sheet forming step includes: a first coating liquid applying step of applying a first coating liquid containing a first conductive polymer and a first liquid medium into voids in the separator; a first liquid medium removing step of removing at least a portion of the first liquid medium from the first coating liquid to form the sheet;
  • the electrical resistivity in the thickness direction of the sheet is 300 k ⁇ cm or less, The method for producing an electrolytic capacitor,
  • the method further includes a polymer layer forming step of forming a second conductive polymer layer on a surface of the dielectric layer before the laminate forming step,
  • the polymer layer forming step includes: a second coating liquid application step of applying a second coating liquid containing a second conductive polymer and a second liquid medium to a surface of the dielectric layer; and a second liquid medium removing step of removing at least a part of the second liquid medium from the second coating liquid to form the second conductive polymer layer.
  • the cathode foil has an inorganic layer on a surface thereof, 15.
  • Capacitor A1 An electrolytic capacitor (capacitor A1) was produced by the following method.
  • a nonwoven fabric (thickness 50 ⁇ m) was prepared as a separator.
  • the nonwoven fabric used was made of polyester fiber, aramid fiber, and cellulose.
  • a dispersion liquid (commercially available product) in which particles of polyethylenedioxythiophene (PEDOT) doped with polystyrene sulfonic acid (PSS) were dispersed in water was prepared.
  • the concentration of the conductive polymer component in the coating liquid was 2.0 wt. %.
  • a gravure coater was used to apply the coating liquid to one side of the anode foil (surface of the dielectric layer).
  • a drying process was then performed to form a second conductive polymer layer on one side of the anode foil (surface of the dielectric layer). The drying process was performed by heating the anode foil with the coating liquid applied at 125°C for 5 minutes.
  • a second conductive polymer layer was formed on the other side of the anode foil (surface of the dielectric layer) in the same manner.
  • the coating liquid was applied to the separator and then dried to form a first conductive polymer layer in the voids of the separator.
  • a sheet a1 was formed that included a separator and one conductive polymer layer.
  • Capacitor A1 Sealing of Capacitor Element
  • the capacitor element impregnated with the electrolytic solution was sealed to produce an electrolytic capacitor as shown in Fig. 1. Then, aging was performed for 90 minutes at 95°C while applying a voltage. In this manner, an electrolytic capacitor (capacitor A1) was produced.
  • the airflow resistance of the prepared sheets a1 to a3 and c1 to c2 was measured by a breathability tester. Specifically, the measurement was performed by the following method. First, the sheet was cut into 5 cm squares to prepare a sample. The sample was set in the opening (opening area: 2 ⁇ cm 2 ) of the breathability tester. Next, air was allowed to pass through the sample at a permeation rate of 4 cm 3 /cm 2 ⁇ s (4 cm 3 per cm 2 and 1 second). Then, the pressure loss due to the sample at that time was measured. The airflow resistance was calculated from the measured pressure loss.
  • the airflow resistance tester (KES-F8) made by Kato Tech Co., Ltd. was used as the breathability tester.
  • Capacitors A1 to A3 are electrolytic capacitors (E) according to the present disclosure manufactured by manufacturing method (M).
  • Capacitors C1 to C2 are comparative example capacitors.
  • Sheets a1 to a3 are sheets (S) according to the present disclosure.
  • Sheets c1 and c2 are comparative example sheets.
  • the ESR and leakage current of capacitors A1 to A3 were low. This is believed to be due to the low airflow resistance of sheets a1 to a3.
  • the ESR of capacitor C1 was high.
  • the airflow resistance of sheet c1 was low, and it is believed that the amount of conductive polymer layer formed on sheet c1 was too small, which caused the high ESR of capacitor C1.
  • the airflow resistance of sheet c2 was high, and the leakage current of capacitor C2 was high.
  • This disclosure can be used in electrolytic capacitors.
  • Capacitor element 11 Anode foil 12: Cathode foil 13: Sheet 100: Electrolytic capacitor

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Publication number Priority date Publication date Assignee Title
WO2013054888A1 (ja) * 2011-10-13 2013-04-18 特種東海製紙株式会社 電気化学素子用セパレータ及びその製造方法
WO2020022472A1 (ja) * 2018-07-26 2020-01-30 パナソニックＩｐマネジメント株式会社 電解コンデンサ
WO2020158780A1 (ja) * 2019-01-31 2020-08-06 パナソニックＩｐマネジメント株式会社 電解コンデンサおよびその製造方法
WO2020158783A1 (ja) * 2019-01-31 2020-08-06 パナソニックＩｐマネジメント株式会社 導電性高分子分散液、電解コンデンサならびに電解コンデンサの製造方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013054888A1 (ja) * 2011-10-13 2013-04-18 特種東海製紙株式会社 電気化学素子用セパレータ及びその製造方法
WO2020022472A1 (ja) * 2018-07-26 2020-01-30 パナソニックＩｐマネジメント株式会社 電解コンデンサ
WO2020158780A1 (ja) * 2019-01-31 2020-08-06 パナソニックＩｐマネジメント株式会社 電解コンデンサおよびその製造方法
WO2020158783A1 (ja) * 2019-01-31 2020-08-06 パナソニックＩｐマネジメント株式会社 導電性高分子分散液、電解コンデンサならびに電解コンデンサの製造方法

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