Electrolytic capacitor

Abstract

The electrolytic capacitor of the present application has a capacitor element containing: an anode body extending along a first direction, a dielectric layer covering at least a part of the anode body, and a cathode lead-out layer containing a conjugated polymer and covering at least a part of the dielectric layer, the anode body having, along the first direction: a solid electrolyte formation portion in which a solid electrolyte layer is formed in at least a part, an anode portion, and a separation portion provided between the solid electrolyte formation portion and the anode portion, the conjugated polymer containing an electrically conductive polymer, in a case where a solid electrolyte layer formed between the cathode lead-out layer and the dielectric layer is set as a first solid electrolyte layer, in a Raman spectrum of the first solid electrolyte layer, when a peak attributed to a CC stretching vibration originating from the conjugated polymer is fitted with a Lorentz function, a full width at half maximum of the above-mentioned peak is 50 cm ‑1 or more and 70 cm ‑1 or less.

Description

Technical Field

[0001] This invention relates to electrolytic capacitors. Background Technology

[0002] An electrolytic capacitor, for example, has a capacitor element comprising an anode body, a dielectric layer covering at least a portion of the anode body, a solid electrolyte layer covering at least a portion of the dielectric layer, and a cathode lead-out layer covering at least a portion of the solid electrolyte layer. In the capacitor element, the anode body, for example, has a solid electrolyte forming portion on which the solid electrolyte layer is formed, an anode portion, and a separating portion disposed between the solid electrolyte forming portion and the anode portion. In such capacitor elements, it is known to use a solid electrolyte layer comprising a conductive polymer.

[0003] Patent Document 1 describes a solid electrolytic capacitor in which a barrier zone (equivalent to a separation section) is provided within a roughened layer or porous layer formed on the surface of a valve-acting metal to prevent the penetration of conductive polymer material, thus forming at least the boundary between the anode lead and the capacitor element portion. A dielectric oxide film layer, a conductive polymer layer, and a conductive layer are sequentially formed on the surface of the capacitor element portion divided by this barrier zone. Terminals are mounted on the surface of the anode lead and the conductive layer, respectively. Furthermore, Patent Document 1 states that the solid electrolytic capacitor configured as described above significantly reduces the probability of the conductive polymer layer reaching the anode lead, causing poor insulation or insulation failure.

[0004] Patent Document 2 describes a solid electrolytic capacitor in which a shielding layer (corresponding to a separation portion) formed by stacking multiple layers is provided in the region separating the anode and cathode regions of a solid electrolytic capacitor substrate having a porous surface layer. Furthermore, Patent Document 2 describes that a first shielding layer, formed directly stacked on the solid electrolytic capacitor substrate, is a shielding layer formed from a solution or dispersion of a heat-resistant resin or its precursor that does not contain shielding layer modifying additives (excluding silane coupling agents), or in which the content of the shielding layer modifying additive is 0.1% by mass or less (based on the mass of the heat-resistant resin or its precursor). Additionally, Patent Document 2 describes that in the solid electrolytic capacitor configured as described above, the anode and cathode regions can be insulated more reliably.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2000-243665

[0008] Patent Document 2: International Publication No. 2008 / 038584 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, in electrolytic capacitors like the one described above, the solid electrolyte layer containing conductive polymers is in contact with air, and sometimes the conductive polymers can oxidize and deteriorate due to the oxygen contained in the air. Moreover, if the conductive polymers oxidize and deteriorate, the electrolytic capacitor may not be able to fully perform its functions.

[0011] However, in any known literature, beginning with the aforementioned patent documents 1 and 2, it is difficult to say that sufficient research has been conducted on effectively suppressing the oxidative degradation of conductive polymers.

[0012] Therefore, the present invention provides an electrolytic capacitor capable of sufficiently suppressing the oxidative degradation of conductive polymers.

[0013] Methods for solving problems

[0014] This invention relates to an electrolytic capacitor comprising a capacitor element, the capacitor element including: an anode body extending along a first direction, a dielectric layer covering at least a portion of the anode body, a solid electrolyte layer comprising a conjugated polymer and covering at least a portion of the dielectric layer, and a cathode lead-out layer covering at least a portion of the solid electrolyte layer. The anode body, along the first direction, has: a solid electrolyte forming portion on which at least a portion of the solid electrolyte layer is formed, an anode portion, and a separation portion disposed between the solid electrolyte forming portion and the anode portion. The conjugated polymer comprises a conductive polymer. When the solid electrolyte layer formed between the cathode lead-out layer and the dielectric layer is designated as the first solid electrolyte layer, in the Raman spectrum of the first solid electrolyte layer, when the peaks at which the C-C stretching vibrations originating from the conjugated polymer are fitted using the Lorentz function, the full width at half maximum (FWHM) of the peaks is 50 cm⁻¹. -1 Above and 70cm -1 the following.

[0015] Invention Effects

[0016] According to the present invention, an electrolytic capacitor capable of sufficiently suppressing the oxidative degradation of conductive polymers can be provided. Attached Figure Description

[0017] Figure 1 This is a schematic cross-sectional view of a capacitor element according to one embodiment of the present invention.

[0018] Figure 2 This is a schematic cross-sectional view of an electrolytic capacitor according to one embodiment of the present invention. Detailed Implementation

[0019] The following examples illustrate embodiments of the present invention, but the present invention is not limited to the examples described below. In the following description, specific numerical values ​​and materials are illustrated, but other numerical values, materials, etc., can be applied as long as the effects of the present invention are achieved. It should be noted that the constituent elements of the characteristic parts of the present invention can also use known constituent elements. In this specification, when referred to as the "range of numerical value A to numerical value B," this range includes both numerical value A and numerical value B.

[0020] In the following description, when lower and upper limits of values ​​related to specific physical properties, conditions, etc. are given, any of the given lower limits can be combined with any of the given upper limits as long as the lower limit is not above the upper limit. When multiple materials are given, unless otherwise specified, one of them can be used alone or in combination with two or more.

[0021] This invention includes a combination of the contents described in any two or more technical solutions selected from the plurality of technical solutions described in the appended claims. In other words, as long as no technical contradiction arises, the contents described in any two or more technical solutions selected from the plurality of technical solutions described in the appended claims can be combined.

[0022] Electrolytic capacitors

[0023] An electrolytic capacitor according to an embodiment of the present invention has a capacitor element comprising: an anode body extending along a first direction, a dielectric layer covering at least a portion of the anode body, a solid electrolyte layer comprising a conjugated polymer and covering at least a portion of the dielectric layer, and a cathode lead-out layer covering at least a portion of the solid electrolyte layer. In the capacitor element, the anode body along the first direction has: a solid electrolyte forming portion on which the solid electrolyte layer is formed in at least a portion, an anode portion, and a separation portion disposed between the solid electrolyte forming portion and the anode portion. In the capacitor element, the conjugated polymer comprises a conductive polymer, and when the solid electrolyte layer formed between the cathode lead-out layer and the dielectric layer is designated as the first solid electrolyte layer, in the Raman spectrum of the first solid electrolyte layer, when the Lorentz function of the peak attributable to the CC stretching vibration originating from the conjugated polymer is fitted, the full width at half maximum (FWHM) of the peak is 50 cm⁻¹. -1 Above and 70cm -1 the following.

[0024] In the electrolytic capacitor of the embodiments of the present invention, it is important that a portion of the solid electrolyte layer of the capacitor element meets specific conditions. Specifically, it is important that when the solid electrolyte layer formed between the cathode lead-out layer and the dielectric layer is designated as the first solid electrolyte layer, the full width at half maximum (FWHM) of the peak in the Raman spectrum of the first solid electrolyte layer is 50 cm⁻¹ when the Lorentz function of the peak attributed to the C-C stretching vibration originating from the conjugated polymer is fitted. -1 Above and 70cm -1 The following is an explanation of the reason.

[0025] For an anode body having a solid electrolyte forming section, an anode section, and a separation section disposed between the solid electrolyte forming section and the anode section along the first direction, i.e., for an anode body having the anode section, the separation section, and the solid electrolyte forming section arranged sequentially from one end of the first direction to the other, air from the first direction penetrates into the interior of the solid electrolyte layer from one end to the other. Furthermore, if the solid electrolyte layer contains a conductive polymer as a conjugated polymer, this conductive polymer oxidizes and deteriorates due to the air penetrating into the solid electrolyte layer. Moreover, when air from the atmosphere sufficiently penetrates to the other end of the first direction, i.e., when air from the atmosphere sufficiently penetrates into the interior of the first solid electrolyte layer formed between the cathode lead-out layer and the dielectric layer, the oxidation and deterioration of the conductive polymer in the first solid electrolyte layer becomes significant. Thus, when the oxidation and deterioration of the conductive polymer in the first solid electrolyte layer becomes significant, the conductivity of the first solid electrolyte layer deteriorates, resulting in a decrease in the reliability (e.g., capacitance retention) of the electrolytic capacitor.

[0026] However, regarding the electrolytic capacitor of the embodiment of the present invention, in the Raman spectrum of the first solid electrolyte layer, when the Lorentz function of the peak attributed to the C-C stretching vibration originating from the conjugated polymer is fitted, the full width at half maximum (FWHM) of the peak is 50 cm⁻¹. -1 Above and 70cm -1 The first solid electrolyte layer contains highly crystalline conductive polymers. Therefore, it is considered that these highly crystalline conductive polymers create a dense structure in the first solid electrolyte layer, thus inhibiting the sufficient intrusion of atmospheric air into the interior of the first solid electrolyte layer. As a result, it is believed that significant oxidative degradation of the conductive polymers caused by atmospheric air can be effectively suppressed within the first solid electrolyte layer.

[0027] As mentioned above, in the Raman spectrum of the first solid electrolyte layer, when the Lorentz function of the peak attributed to the C-C stretching vibration originating from the conjugated polymer is fitted, the full width at half maximum (FWHM) of the peak is 50 cm⁻¹. -1Above and 70cm -1 This means that the first solid electrolyte layer contains a highly crystalline conductive polymer. Furthermore, to improve the crystallinity of the conductive polymer in the first solid electrolyte layer, it is preferable to improve the orientation of the conductive polymer in the first solid electrolyte layer. Moreover, to improve the orientation of the conductive polymer, it is preferable to polymerize the monomers constituting the conductive polymer (hereinafter, also simply referred to as monomers) for a certain period of time. For example, when obtaining a conductive polymer by polymerizing monomers through electrolytic polymerization, it is preferable to appropriately adjust the electrical energy (e.g., voltage, current, etc.) applied to the region forming the first solid electrolyte layer in the solid electrolyte forming section. The greater the electrical energy, the faster the monomers polymerize, and therefore the lower the crystallinity of the resulting conductive polymer. On the other hand, the lower the electrical energy, the longer the monomers polymerize, and therefore the higher the crystallinity of the resulting conductive polymer.

[0028] Furthermore, when obtaining a conductive polymer by polymerizing monomers through electrolytic polymerization, it is preferable to gradually apply electrical energy to the region in the solid electrolyte forming section where the first solid electrolyte layer can be formed. For example, it is preferable to apply electrical energy from one end side (anode side) of the anode body to the other end side (solid electrolyte layer forming section side). This allows the first solid electrolyte layer to be formed in the solid electrolyte forming section in a manner containing a highly crystalline conductive polymer. It should be noted that when a solid electrolyte layer (the second solid electrolyte layer described later) is also formed closer to the separation section than the first solid electrolyte layer, the conductive polymer contained in this second solid electrolyte layer can polymerize rapidly or after a certain period of time. That is, the crystallinity of the conductive polymer contained in the second solid electrolyte layer can be low or high. For example, the conductive polymer contained in the second solid electrolyte layer may not necessarily satisfy a peak full width at half maximum (FWHM) of 50 cm⁻¹. -1 Above and 70cm -1 The following characteristics can also be satisfied.

[0029] In this specification, the Raman spectrum of the first solid electrolyte layer is the spectrum measured under the following conditions at a cross-section at a specified position in the thickness direction of the first solid electrolyte layer.

[0030] condition

[0031] Raman spectrometer: NanoPhoton RamanFORCE PAV

[0032] • Diffraction grating: 600gr / cm

[0033] • Wavenumber measurement range: 0 cm -1 Above and 2500cm -1 the following

[0034] Temperature: 25℃

[0035] It should be noted that the laser wavelength, laser power density, and exposure time are determined based on the type of conjugated polymer. For example, when the conjugated polymer is polypyrrole, the laser wavelength is 532 nm and the laser power density is 140 W / cm². 2 The exposure time was 75 seconds. With the conjugated polymer being poly(3,4-ethylenedioxythiophene) (PEDOT), the irradiation laser wavelength was 785 nm, and the laser power density was 660 W / cm². 2 The exposure time is 60 seconds.

[0036] In Raman spectroscopy measurements, samples collected according to the following steps can be used. It should be noted that the full width at half maximum (FWHM) of the Raman peaks can also be the arithmetic mean of the measured values ​​from samples A through C below.

[0037] step

[0038] (1) After embedding the solid electrolytic capacitor into the curing resin, the curing resin is cured to obtain a cured body containing the electrolytic capacitor.

[0039] (2) The cured body is ground or polished to expose a cross-section parallel to the thickness direction of the first solid electrolyte layer (a cross-section perpendicular to the first direction of the anode). Regarding the cross-section, when the length of the first solid electrolyte layer along the first direction is set to 1, the cross-sections are defined as follows: a cross-section located 0 to 0.05 units away from one end of the first solid electrolyte layer (the end closer to the separation section) in the first direction (hereinafter referred to as the first cross-section); a cross-section located 0 to 0.05 units away from the other end of the first solid electrolyte layer (the end furthest from the separation section) in the first direction (hereinafter referred to as the second cross-section); and a cross-section located 0 to 0.025 units away from the center of the first solid electrolyte layer (the midpoint between one end and the other end) in the first direction, offset towards one end and the other end respectively (hereinafter referred to as the third cross-section). Thus, a test sample A having the first cross-section, a test sample B having the second cross-section, and a test sample C having the third cross-section are obtained.

[0040] (3) In the first section of sample A, the second section of sample B, and the third section of sample C, Raman spectra were measured on one main surface side (the main surface side forming the cathode lead-out layer) and the other main surface side (the main surface side covered by the dielectric layer) of the first solid electrolyte layer. On one main surface side of the first solid electrolyte layer, Raman spectra were measured on the portion from one main surface to a depth of 10 nm (hereinafter also referred to as the surface portion). On the other main surface side of the first solid electrolyte layer, when pores and depressions (hereinafter also referred to as pits) are formed from the surface of the anode body towards the center due to surface roughening, Raman spectra were measured on the first solid electrolyte layer formed in the pits. It should be noted that when the surface of the anode body is not roughened, Raman spectra are also measured on the surface portion of the other main surface side, similar to one main surface side. The full width at half maximum (FWHM) and peak position of the peaks attributable to the CC stretching vibrations were calculated by arithmetic averaging of measurements taken at 6 locations in an 8μm × 8μm region on the surface and at 12 locations in an 8μm × 8μm region of the first solid electrolyte layer formed in the pit.

[0041] The structure of the electrolytic capacitor according to an embodiment of the present invention will be described below.

[0042] <Capacitor Components>

[0043] As described above, the capacitor element comprises: an anode body extending along a first direction, a dielectric layer covering at least a portion of the anode body, a solid electrolyte layer comprising a conjugated polymer and covering at least a portion of the dielectric layer, and a cathode lead-out layer covering at least a portion of the solid electrolyte layer.

[0044] (Anode)

[0045] As described above, the anode body, along the first direction, includes: a solid electrolyte forming portion on which a solid electrolyte layer is formed in at least a portion, an anode portion, and a separation portion disposed between the solid electrolyte forming portion and the anode portion. The anode portion is the part of the anode body on which no solid electrolyte layer is formed. A porous portion may also be formed on at least one main surface side of the anode body. It should be noted that a core portion may also be disposed on the central portion side of the anode body. A thin-walled portion is formed in a portion of the separation portion, and a separation member is disposed in the thin-walled portion.

[0046] Regarding the anode body, it comprises a shaped or sintered body containing a foil (metal foil) containing a valve-acting metal as a conductive material or particles containing a valve-acting metal. The shaped or sintered body has a porous structure. Examples of valve-acting metals include titanium, tantalum, aluminum, and niobium. The anode body contains one or more of the aforementioned valve-acting metals. The anode body may contain the aforementioned valve-acting metals in the form of an alloy or intermetallic compound. The thickness of the anode body is not particularly limited. When the anode body is a foil, the thickness of the anode body other than the thin-walled portion is, for example, 15 μm or more and 300 μm or less. The aforementioned thickness is preferably 80 μm or more and 250 μm or less. When the anode body is a shaped or sintered body, the thickness of the anode body other than the thin-walled portion is, for example, 15 μm or more and 5 mm or less.

[0047] When the anode body is a foil, it is preferable to roughen at least one main surface of the anode body by electrolytic etching or the like. This allows a porous portion to be formed on at least one main surface of the anode body, which is a foil. When the anode body is a shaped or sintered body, the anode body is generally porous. On the other hand, from the viewpoint of improving strength, the anode body preferably has a porous portion formed on at least one main surface and a deep portion disposed on the central portion side. The porous portion is a region having multiple micropores. The core portion is, for example, a region that has not been electrolytically etched.

[0048] (Dielectric layer)

[0049] As described above, a dielectric layer covers at least a portion of the anode body. The dielectric layer is formed on at least a portion of the surface of the anode body. The dielectric layer is formed, for example, by anodizing the valve-acting metal of the anode body using a chemical conversion treatment or similar method. Therefore, the dielectric layer may contain an oxide of the valve-acting metal. For example, if aluminum is used as the valve-acting metal, the dielectric layer may contain Al₂O₃; if tantalum is used as the valve-acting metal, the dielectric layer may contain Ta₂O₅. It should be noted that the dielectric layer is not limited to these, as long as it functions as a dielectric.

[0050] (Solid electrolyte layer)

[0051] As described above, the solid electrolyte layer comprises a conjugated polymer and is a portion of the coated dielectric layer. The solid electrolyte layer is formed in the solid electrolyte forming portion within the anode body. The solid electrolyte layer may also be formed in a manner that covers the entire surface of the dielectric layer.

[0052] Conjugated polymers include conductive polymers. Examples of conductive polymers include polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, polyphenylene, polyphenylene vinylidene, polyphenylene oxide, and polythiophene vinylidene. Conductive polymers can be used alone or in combination of two or more. Furthermore, conductive polymers can also be copolymers of two or more monomers.

[0053] It should be noted that in this specification, polypyrrole, polythiophene, polyfuran, and polyaniline refer to polymers with polypyrrole, polythiophene, polyfuran, and polyaniline as their basic backbones, respectively. Therefore, polypyrrole, polythiophene, polyfuran, and polyaniline also include their respective derivatives. For example, polythiophene includes poly(3,4-ethylenedioxythiophene) (PEDOT), etc.

[0054] The conductive polymer can be contained in the solid electrolyte layer along with a dopant. The dopant can be a monomolecular anion or a polymeric anion. Examples of monomolecular anions include p-toluenesulfonic acid and naphthalenesulfonic acid. Examples of polymeric anions include polyvinylsulfonic acid, polystyrenesulfonic acid, polyallylsulfonic acid, polyacrylylsulfonic acid, polymethylpropylenesulfonic acid, poly(2-acrylamido-2-methylpropanesulfonic acid), polyisoprenesulfonic acid, and polyacrylic acid. A single dopant can be used, or two or more can be used in combination. The dopant can be a polymer of a single monomer or a copolymer of two or more monomers. Among these, polymeric anions derived from polystyrenesulfonic acid (e.g., PSS) are preferred.

[0055] Conductive polymers can be obtained by chemical oxidative polymerization or electrolytic polymerization of the monomers that make up the conductive polymers (hereinafter referred to as monomers).

[0056] Chemical oxidative polymerization can be carried out by using solvents, oxidants, monomers, and dopants as needed to chemically oxidize the monomers. Examples of solvents include water, sulfuric acid, methanol, ethanol, propanol, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, chloroform, dichloromethane, carbon tetrachloride, benzene, toluene, xylene, tetrahydrofuran, N-methyl-2-pyrrolidone, and propylene carbonate. The monomers and dopants are appropriately selected based on the target conductive polymer. Oxidants include ferric oxide, triferric(III)(p-toluenesulfonate), sodium persulfate, potassium persulfate, ammonium persulfate, hydrogen peroxide, and potassium permanganate. It should be noted that the polymerization conditions for chemical oxidative polymerization can be appropriately selected based on the solvent, oxidant, monomer, and the type of dopant used as needed.

[0057] In electrolytic polymerization, monomers are polymerized in a solvent to obtain conductive polymers. Dopants can also be used in electrolytic polymerization as needed. The solvents exemplified above can be used. The monomers and dopants are appropriately selected based on the target conductive polymer.

[0058] Examples of electrolytic polymerization include: methods using a potentiostat to polymerize monomers in a solvent containing dissolved monomers and, as needed, dopant compounds (hereinafter referred to as monomer-containing solvents) by applying a potential scanning method or a constant voltage method; and methods using a galvanometer to polymerize monomers in a monomer-containing solvent by applying a constant current method. It should be noted that the dopant compound functions as an electrolyte in the monomer-containing solvent. The conditions for the potential scanning method, the constant voltage method, and the galvanometer method can be appropriately selected based on the solvent, the monomer, and the type of dopant used as needed.

[0059] The solid electrolyte layer has at least a first solid electrolyte layer formed between the cathode lead-out layer and the dielectric layer (described later). In addition to the first solid electrolyte layer, the solid electrolyte layer may also have a second solid electrolyte layer formed further away from the separation portion than the first solid electrolyte layer. The cathode lead-out layer is typically not formed on the second solid electrolyte layer. Therefore, the surface of the second solid electrolyte layer is usually exposed. In this case, the second solid electrolyte layer does not contribute to the capacitance performance of the electrolytic capacitor.

[0060] When the solid electrolyte layer includes a second solid electrolyte layer in addition to the first solid electrolyte layer, the thickness L of the second solid electrolyte layer is... C2 Relative to the thickness L of the first solid electrolyte layer C1 The ratio (L) C2 / L C1 Preferred to satisfy L C2 / L C1 The relationship is ≤1 / 10. Electrolytic polymerization is usually carried out by applying electrical energy from the anode side after the monomer-containing solvent is applied to the region in the solid electrolyte forming section where the first solid electrolyte layer can be formed (hereinafter referred to as the first region). For example, it is carried out by applying electrical energy to the separation section before the separation component is configured. At this time, a portion of the monomer-containing solvent flows from the first region to the separation section, and sometimes a solid electrolyte layer (second solid electrolyte layer) is also formed in the region between the first region and the separation section (hereinafter referred to as the second region). In this case, the second solid electrolyte layer is formed in the second region by monomer polymerization, and a portion of the electrical energy applied from the anode side is consumed. However, if the thickness L of the first solid electrolyte layer is... C1 and the thickness L of the second solid electrolyte layer C2 Satisfying the above relationship, i.e., L C1 Sufficiently greater than L C2Therefore, even if a portion of the electrical energy applied from the anode side is consumed due to the polymerization of monomers in the second region, a sufficient amount of electrical energy can still be supplied to the first region. Thus, even under these circumstances, the crystallinity of the conductive polymer contained in the first solid electrolyte layer can be sufficiently improved. The thickness L of the first solid electrolyte layer... C1 and the thickness L of the second solid electrolyte layer C2 The measurement can be performed as follows: First, disassemble the solid electrolytic capacitor, remove the capacitor element, and obtain an image of the cross-section of the capacitor element using a scanning electron microscope (SEM). Next, using this image, measure the thickness of any 10 points on the first and second solid electrolyte layers. Then, calculate the arithmetic mean of the measured values ​​for the first and second solid electrolyte layers, respectively.

[0061] The solid electrolyte layer may also consist of only a first solid electrolyte layer. By having only a first solid electrolyte layer, as described above, in the second region of the solid electrolyte formation section, it is possible to suppress the consumption of a portion of the electrical energy applied from the anode side by the polymerization of the monomers. Therefore, since a sufficient amount of electrical energy can be further supplied to the first region, the crystallinity of the conductive polymer contained in the first solid electrolyte layer can be further and sufficiently improved.

[0062] In the anode body, as described later, the separation section includes a separation member. When the separation section includes a separation member, the first solid electrolyte layer and the separation member preferably have opposing ends spaced at least 0.18 mm apart in the first direction. With this configuration, the ends of the first solid electrolyte layer and the ends of the separation member are sufficiently spaced apart, thus, as described above, even when electrical energy is supplied from the separation section before the separation member is configured, it is easy to gradually apply electrical energy to the first region. This further facilitates a substantial improvement in the crystallinity of the conductive polymer contained in the first solid electrolyte layer.

[0063] As described above, when the separation section has a separation member, in the first direction, the length between the first end portion of the first solid electrolyte layer and the second end portion of the separation member opposite to the first end portion is preferably 2.8% or more relative to the length of the anode body. With this configuration, since the first end portion of the first solid electrolyte layer and the second end portion of the separation member are also sufficiently spaced, as described above, even when electrical energy is supplied from the separation section before the separation member is positioned, it is easy to gradually apply electrical energy to the first region. This further facilitates a substantial improvement in the crystallinity of the conductive polymer contained in the first solid electrolyte layer.

[0064] The first solid electrolyte layer is preferably composed of at least two layers of solid electrolyte. Furthermore, of the at least two solid electrolyte layers, the outermost solid electrolyte layer is preferably formed by electrolytic polymerization. For example, the first solid electrolyte layer preferably includes a pre-coating layer as the first layer and a second layer stacked on top of the first layer, the second layer being formed by electrolytic polymerization. The first and second layers preferably contain different conductive polymers. For example, the first layer preferably contains polyaniline as a conductive polymer, and the second layer preferably contains PEDOT / PSS as a conductive polymer. As described above, since the pre-coating layer as the first layer contains a conductive polymer, the power supply speed (power supply speed) from the anode side can be increased when the second layer is formed by electrolytic polymerization. This promotes the formation of the second layer. It should be noted that even when the first solid electrolyte layer is composed of three or more layers, by providing the pre-coating layer as the first layer as described above, the formation of the outermost layer can be promoted when it is formed by electrolytic polymerization.

[0065] The second solid electrolyte layer is preferably formed solely by electrolytic polymerization. In electrolytic polymerization, the amount of electrical energy can be easily adjusted. Therefore, if the second solid electrolyte layer is formed solely by electrolytic polymerization, the crystallinity of the conductive polymer contained in the second solid electrolyte layer can be easily adjusted by changing the amount of electrical energy. This allows for relatively easy improvement of the crystallinity of the conductive polymer contained in the second solid electrolyte layer, resulting in excellent heat resistance for the second solid electrolyte layer.

[0066] (Cathode lead-out layer)

[0067] As described above, the cathode lead-out layer covers at least a portion of the solid electrolyte layer. The cathode lead-out layer may also be formed to cover the entire surface of the solid electrolyte layer. The cathode lead-out layer is formed to at least cover the first solid electrolyte layer.

[0068] The cathode lead-out layer may have, for example, a carbon layer and a metal (e.g., silver) paste layer formed on the surface of the carbon layer. The cathode lead-out layer is not limited to the above configuration, as long as it has a current-collecting function.

[0069] Carbon Layer

[0070] The carbon layer contains carbon materials and is electrically conductive. There are no particular limitations on the carbon materials used. Examples of carbon materials include graphite, carbon black, graphene sheets, and carbon nanotubes.

[0071] Depending on the requirements, the carbon layer may also contain at least one of a binder resin and an additive. The binder resin is not particularly limited, and any known binder resin used in the manufacture of capacitor elements may be used. Examples of binder resins include thermosetting resins and thermoplastic resins. Examples of thermosetting resins include epoxy resins, polyimide resins, silicone resins, phenolic resins, urea resins, melamine resins, unsaturated polyester resins, and curable acrylic resins. Examples of thermoplastic resins include polyamide resins, polyamide-imide resins, polyolefin resins, and polyester resins. Examples of additives include dispersants, surfactants, antioxidants, preservatives, alkalis, and acids.

[0072] Metal Paste Layer

[0073] The metal paste layer contains a metallic material. The metallic material is not particularly limited. From an electrical conductivity point of view, the metallic material preferably contains silver.

[0074] There is no particular limitation on the volume ratio of metal material contained in the metal paste layer as long as it exceeds 0%. In cases where resistance is likely to decrease, the aforementioned volume ratio can be 60% or more, 70% or more, or 80% or more.

[0075] The metal paste layer may also contain a binder resin. The volume percentage of the binder resin in the metal paste is not particularly limited. From a resistivity perspective, the aforementioned volume percentage can be 60% or less, 20% or less, or 10% or less. The aforementioned volume percentage can be 0.1% or more, or 0%. The volume percentages of each component in the metal paste layer can be determined, for example, by energy dispersive X-ray spectroscopy (SEM-EDX).

[0076] There is no particular limitation on the thickness of the metal paste layer. For example, the thickness can be greater than 0.1 μm and less than 50 μm, or greater than 1 μm and less than 20 μm. The thickness of the metal paste layer is the arithmetic mean of any five points on a cross-section along the thickness direction.

[0077] (Separated components)

[0078] The separating component preferably has high insulation properties. The separating component covers at least a portion of the surface of the separating section. This suppresses the occurrence of short circuits between the anode section and the cathode lead-out layer.

[0079] The separating component can also be a conventionally known insulating tape (anti-corrosion tape). Regarding the separating component, it can also be formed by adhering a resin composition containing a curable resin to at least a portion of the surface of the separating part. The curable resin can be a thermosetting resin or a photocurable resin. Photocurable resins can also be resins that cure under visible light or ultraviolet light. Examples of curable resins include epoxy resins, polyimide resins, silicone resins, phenolic resins, urea resins, melamine resins, unsaturated polyester resins, furan resins, polyurethane resins, curable acrylic resins, and photoresist resins. Depending on the need, the above-mentioned resin composition may also contain curing agents, curing accelerators, flame retardants, fillers, coupling agents, colorants, release agents, and inorganic ion scavengers. Various known substances can be used. In addition to the curable resin, the above-mentioned resin composition may also contain thermoplastic resins (e.g., polyamide resins, polyamide-imide resins, polyolefin resins, and polyester resins).

[0080] The electrolytic capacitor of the embodiments of the present invention only needs to have at least one of the above-described capacitor elements. For example, in the case where the electrolytic capacitor of the embodiments of the present invention has multiple capacitor elements, at least one of the multiple capacitor elements is the above-described capacitor element, and the other capacitor elements may be conventionally known capacitor elements. On the other hand, in this case, it is preferable that all of the multiple capacitor elements are the above-described capacitor elements.

[0081] In embodiments of the present invention, when the electrolytic capacitor has multiple capacitor elements, the multiple capacitor elements are stacked. The number of stacked capacitor elements is not particularly limited. For example, the number of stacked capacitor elements is 2 or more and 20 or less. The anode portions of the stacked capacitor elements are electrically connected to each other by bonding, such as welding. The cathode lead-out layers of the stacked capacitor elements are also electrically connected to each other in the same way as the anode portions.

[0082] <Exterior body>

[0083] The electrolytic capacitor of the present invention may also include an outer casing that seals the capacitor element. The outer casing protects the capacitor element from impacts and moisture. The outer casing is configured to cover the entire capacitor element. The outer casing is preferably a resin outer casing. For example, epoxy resin can be used as the raw material for the resin outer casing.

[0084] <leader frame>

[0085] The electrolytic capacitor of the present invention may also include a lead frame connected to the capacitor element. The electrolytic capacitor of the present invention may also include an anode lead frame connected to the anode portion of the capacitor element and a cathode lead frame connected to the cathode lead layer of the capacitor element. The anode lead frame is connected to the anode portion, for example, by soldering. The cathode lead frame is connected to the cathode lead layer, for example, by a conductive adhesive or solder, or by resistance welding or laser welding. The conductive adhesive is, for example, a mixture of a curable resin and at least one selected from carbon particles and metal particles.

[0086] Regarding the material of the lead frame, any electrochemically stable and conductive material is acceptable; there are no particular limitations. The lead frame material can be either metallic or non-metallic. The shape of the lead frame is also not particularly limited. From the viewpoint of minimizing height, the thickness of the lead frame (the distance between the opposing main surfaces of the lead frame) is preferably 25 μm or more and 200 μm or less, more preferably 25 μm or more and 100 μm or less.

[0087] A portion of the lead frame is sealed together with the capacitor element by the casing. The remaining portion of the lead frame exposed from the casing is bonded to the substrate via solder.

[0088] The method for manufacturing an electrolytic capacitor according to embodiments of the present invention includes at least a capacitor element manufacturing step for manufacturing capacitor elements. The capacitor element manufacturing step includes: a dielectric layer forming sub-step in which a dielectric layer is formed in such a way as to cover at least a portion of an anode body; a solid electrolyte layer forming sub-step in which a solid electrolyte layer comprising a conjugated polymer is formed in such a way as to cover at least a portion of the dielectric layer; and a cathode lead-out layer forming sub-step in which at least a portion of the solid electrolyte layer is covered.

[0089] The dielectric layer formation sub-step can be carried out by chemically converting at least a portion of the anode body. The chemical conversion process can be carried out, for example, by immersing at least a portion of the anode body in a chemical conversion solution, thereby allowing the chemical conversion solution to permeate the surface of at least a portion of the anode body, then using the anode body as the anode and applying a voltage between it and a cathode immersed in the chemical conversion solution.

[0090] The solid electrolyte layer formation sub-step can be implemented, for example, by attaching a monomer of a conductive polymer (hereinafter referred to as monomer) to at least a portion of the dielectric layer, and then performing chemical oxidative polymerization or electrolytic polymerization on the monomer in at least a portion of the dielectric layer to form a conductive polymer layer. Regarding the attachment of the monomer to at least a portion of the dielectric layer, this can be implemented by immersing at least a portion of the anode body on which the dielectric layer is formed into a polymerization solution containing the monomer. As described above, when the anode body sequentially has an anode portion, a separation portion, and a solid electrolyte forming portion along the first direction, the solid electrolyte forming portion can be immersed in the polymerization solution up to a predetermined distance from the separation portion, and then chemical oxidative polymerization and electrolytic polymerization can be performed. In the case of electrolytic polymerization of the monomer, a voltage in the range of 1V to 5V can be applied to the anode body as electrical energy. Alternatively, electrical energy can be applied from the separation portion using a power supply belt.

[0091] Regarding the conductive polymer layer, it can also be formed by coating a dielectric layer with a treatment liquid containing a conductive polymer to form a film, followed by drying the film. Examples of conductive polymers used include poly(3,4-ethylenedioxythiophene) (PEDOT). Dopant examples include polystyrene sulfonic acid (PSS). The treatment liquid is a dispersion or solution of the conductive polymer. Examples of dispersion media (solvents) include water, organic solvents, or mixtures thereof.

[0092] Regarding the cathode lead-out layer formation sub-step, for example, it can be formed by sequentially stacking a carbon layer and a silver paste layer on at least a portion of the solid electrolyte layer.

[0093] In addition to the capacitor element manufacturing process, the electrolytic capacitor manufacturing method of the embodiments of the present invention may also include a lead frame connection process for connecting the capacitor element to the lead frame, and a sealing process for sealing the capacitor element and the lead frame.

[0094] In the lead frame bonding process, an anode lead frame is connected to the anode body of the capacitor element, and a cathode lead frame is connected to the cathode lead layer of the capacitor element. The anode lead frame is connected to the anode body, for example, by soldering. The cathode lead frame is connected to the cathode lead layer, for example, by a conductive adhesive.

[0095] In the sealing process, a sealing resin is used to cover the entire capacitor element, as well as at least a portion of the anode lead frame and the cathode lead frame. In this sealing process, the outer casing is formed using the sealing resin. For example, epoxy resin can be used as the sealing resin. It should be noted that the remaining portions of the anode lead frame and the cathode lead frame exposed from the outer casing are bonded to the substrate using solder.

[0096] The following is for reference Figure 1 A capacitor element according to one embodiment will be described, with reference to Figure 2An electrolytic capacitor according to one embodiment will be described. However, embodiments of the present invention are not limited to the following.

[0097] Figure 1 This is a schematic cross-sectional view of a capacitor element according to one embodiment.

[0098] The capacitor element 110 is, for example, in a sheet shape. The capacitor element 110 includes an anode body 11 extending along a first direction, a dielectric layer 12 covering at least a portion of the anode body, a solid electrolyte layer 13 covering at least a portion of the dielectric layer 12, and a cathode lead-out layer 14 covering at least a portion of the solid electrolyte layer 13. The cathode lead-out layer 14 has a carbon layer 141 and a metal paste layer 142. It should be noted that in... Figure 1 In the capacitor element 110 shown, the solid electrolyte layer 13 is the first solid electrolyte layer. That is, in Figure 1 The second solid electrolyte layer is not shown.

[0099] The anode body 11 includes: a solid electrolyte forming portion 11c on which a solid electrolyte layer 13 is formed in at least a portion, an anode portion 11a, and a separation portion 11b disposed between the solid electrolyte forming portion 11c and the anode portion 11a. Figure 1 In the example shown, porous portions (not shown) are formed on both main surfaces of the anode body 11. Furthermore, a core portion (not shown) is sandwiched between the two porous portions formed on the two main surfaces. A thin-walled portion is formed on a part of the separation portion 11b. A separation member 15 is disposed on the surface of the thin-walled portion.

[0100] Figure 2 This is a schematic cross-sectional view of an electrolytic capacitor according to one embodiment. The electrolytic capacitor 100 has one or more capacitor elements 110, an anode lead frame 120A bonded to the anode portion 11a, a cathode lead frame 120B bonded to the cathode lead layer, and a sealing resin 130 sealing the capacitor elements 110.

[0101] (Postscript)

[0102] Based on the above description, the following technologies are disclosed.

[0103] (Technology 1)

[0104] An electrolytic capacitor includes a capacitor element comprising: an anode extending along a first direction; a dielectric layer covering at least a portion of the anode; a solid electrolyte layer comprising a conjugated polymer and covering at least a portion of the dielectric layer; and a cathode lead-out layer covering at least a portion of the solid electrolyte layer.

[0105] The anode body, along the first direction, includes: a solid electrolyte forming portion on which the solid electrolyte layer is formed in at least a portion, an anode portion, and a separation portion disposed between the solid electrolyte forming portion and the anode portion.

[0106] The aforementioned conjugated polymer systems include conductive polymers.

[0107] When the solid electrolyte layer formed between the cathode extraction layer and the dielectric layer is designated as the first solid electrolyte layer, in the Raman spectrum of the first solid electrolyte layer, when the peak at half maximum (FWHM) of the peak attributable to the C-C stretching vibration originating from the conjugated polymer is fitted using the Lorentz function, the full width at half maximum (FWHM) of the peak is 50 cm⁻¹. -1 Above and 70cm -1 the following.

[0108] (Technology 2)

[0109] According to the electrolytic capacitor described in Technique 1, wherein,

[0110] The aforementioned solid electrolyte forming section has a second solid electrolyte layer formed on the separation section side, which is closer to the separation section than the first solid electrolyte layer.

[0111] The thickness L of the second solid electrolyte layer mentioned above C2 Relative to the thickness L of the first solid electrolyte layer mentioned above C1 The ratio (L) C2 / L C1 ) satisfies L C2 / L C1 A relationship of ≤1 / 10.

[0112] (Technology 3)

[0113] According to the electrolytic capacitor described in Technique 1, wherein,

[0114] The solid electrolyte forming section described above only has the first solid electrolyte layer described above.

[0115] (Technology 4)

[0116] According to any one of the techniques 1 to 3, the electrolytic capacitor wherein,

[0117] The aforementioned separation section has a separation component.

[0118] The first solid electrolyte layer and the separation component are spaced at least 0.18 mm apart at their opposite ends in the first direction.

[0119] (Technology 5)

[0120] According to any one of the techniques 1 to 3, the electrolytic capacitor wherein,

[0121] The aforementioned separation section has a separation component.

[0122] In the first direction, the length of the interval between the first end portion of the first solid electrolyte layer and the second end portion of the separation member opposite to the first end portion is 2.8% or more relative to the length of the anode body.

[0123] (Technology 6)

[0124] According to any one of the techniques 1 to 5, the electrolytic capacitor wherein,

[0125] The first solid electrolyte layer mentioned above is composed of at least two layers of solid electrolyte layers stacked together.

[0126] (Technology 7)

[0127] According to the electrolytic capacitor described in Technique 6, wherein,

[0128] Of the at least two solid electrolyte layers mentioned above, the outermost solid electrolyte layer is formed by electrolytic polymerization.

[0129] (Technology 8)

[0130] According to any one of techniques 2 and 4 to 7, the electrolytic capacitor wherein,

[0131] The aforementioned second solid electrolyte layer was formed solely through electrolytic polymerization.

[0132] Although the present invention has been described in conjunction with its present preferred embodiments, the above disclosure should not be construed as limiting. Various modifications and variations will be readily apparent to those skilled in the art upon reading the above disclosure. Therefore, the appended claims should be interpreted as covering all modifications and variations without departing from the true spirit and scope of the invention.

[0133] Example

[0134] The present invention will now be described in detail based on embodiments and comparative examples, but the present invention is not limited to the following embodiments.

[0135] (Example 1)

[0136] (1) Fabrication of capacitor components

[0137] An aluminum foil (100 μm thick) was prepared as the anode. The two main surfaces of the aluminum foil were then etched to obtain an anode with porous sections on both main surfaces (35 μm thick on each side). While the anode was immersed in a 0.3% by mass phosphoric acid solution (70°C), a DC voltage of 70 V was applied for 20 minutes, forming a dielectric layer containing aluminum oxide (Al₂O₃) on both main surfaces of the anode.

[0138] The anode body, to which the dielectric layer is formed, is divided into an anode section, a solid electrolyte forming section, and a separation section between them. A portion of the separation section is compressed by stamping to form a thin-walled section (35 μm thick). Then, an insulating anti-corrosion tape (separation component) is attached to the thin-walled section.

[0139] The solid electrolyte forming portion of the anode is immersed in a liquid composition containing a conductive material (polyaniline) to form a pre-coating. The solid electrolyte forming portion is immersed in the liquid composition up to a position 0.18 mm from the separation portion. A polymerization solution containing pyrrole (a monomer of a conductive polymer), naphthalenesulfonic acid (a dopant), and water is prepared. After immersing the pre-coated solid electrolyte forming portion in the obtained polymerization solution, electrolytic polymerization is performed with an applied voltage of 3V to form a solid electrolyte layer on the pre-coating. It should be noted that this solid electrolyte layer corresponds to the first solid electrolyte layer described in the above embodiment. Regarding the voltage, a power supply is applied from the separation portion using a power supply belt. The solid electrolyte forming portion is immersed in the polymerization solution up to a position 0.18 mm from the separation portion.

[0140] A dispersion of graphite particles in water is applied to the surface of the solid electrolyte layer to form a film, which is then dried. This forms a carbon layer on the solid electrolyte layer. Next, a silver paste containing silver particles and an adhesive resin (epoxy resin) is applied to the surface of the carbon layer to form a film, which is then heated to cure the adhesive resin. This forms a silver paste layer (15 μm thick) on the carbon layer. Thus, a cathode lead-out layer consisting of the carbon layer and the silver paste layer is formed, covering a portion of the solid electrolyte layer, thereby obtaining the capacitor element of Example 1.

[0141] Repeating the above steps to fabricate seven capacitor elements of Example 1, these seven capacitor elements are stacked with the ends of the anode portion and the ends of the cathode lead-out layer aligned to obtain a capacitor element stack. Then, in this capacitor element stack, the seven anode portions are joined together by laser welding.

[0142] (2) Assembly of electrolytic capacitors

[0143] Two lead frames (Sn-plated copper lead frames) are joined to the laminate of the capacitor elements. Next, the entire laminate of the capacitor elements and a portion of each lead frame are sealed with a sealing material containing biphenyl-type epoxy resin to form an outer casing. Thus, the electrolytic capacitor of Example 1 is obtained.

[0144] (Example 2)

[0145] The solid electrolyte forming part is immersed in the liquid composition up to a position 0.29 mm from the separation part to form a pre-coating, and the solid electrolyte forming part is immersed in the polymer solution up to a position 0.29 mm from the separation part to form a solid electrolyte layer on the pre-coating. Except as described above, the electrolytic capacitor of Example 2 is obtained by operating in the same manner as in Example 1.

[0146] (Example 3)

[0147] The solid electrolyte forming part is immersed in the liquid composition up to a distance of 0.22 mm from the separation part to form a pre-coating, and the solid electrolyte forming part is immersed in the polymer solution up to a distance of 0.22 mm from the separation part to form a solid electrolyte layer on the pre-coating. Except as described above, the operation is the same as in Example 1 to obtain the electrolytic capacitor of Example 3.

[0148] (Example 4)

[0149] The solid electrolyte forming part is immersed in the liquid composition up to a position 0.27 mm from the separation part to form a pre-coating, and the solid electrolyte forming part is immersed in the polymer solution up to a position 0.27 mm from the separation part to form a solid electrolyte layer on the pre-coating. Except as described above, the operation is the same as in Example 1 to obtain the electrolytic capacitor of Example 4.

[0150] (Example 5)

[0151] The solid electrolyte forming part is immersed in the liquid composition up to a position 0.25 mm from the separation part to form a pre-coating, and the solid electrolyte forming part is immersed in the polymer solution up to a position 0.25 mm from the separation part to form a solid electrolyte layer on the pre-coating. Except as described above, the operation is the same as in Example 1 to obtain the electrolytic capacitor of Example 5.

[0152] (Comparative Example 1)

[0153] The solid electrolyte forming part is immersed in the liquid component until it reaches the boundary with the separation part to form a pre-coating, and the solid electrolyte forming part is immersed in the polymer solution until it reaches the boundary with the separation part to form a solid electrolyte layer on the pre-coating. Except as described above, the operation is the same as in Example 1 to obtain the electrolytic capacitor of Comparative Example 1.

[0154] For the electrolytic capacitors of Examples 1-5 and the electrolytic capacitor of Comparative Example 1, the Raman spectra of the solid electrolyte layer (first solid electrolyte layer) were measured according to the method described in the above embodiments, and the full width at half maximum (FWHM) of the peaks attributable to the CC stretching vibrations was determined. The FWHM of the peaks in the first cross-section of Sample A, the second cross-section of Sample B, and the third cross-section of Sample C are shown in Table 1 below. It should be noted that, as described above, the first cross-section is a cross-section located at a distance of 0 to 0.05 from one end (the end near the separation portion) of the first solid electrolyte layer in the first direction when the length of the first solid electrolyte layer along the first direction is set to 1; the second cross-section is a cross-section located at a distance of 0 to 0.05 from the other end (the end away from the separation portion) of the first solid electrolyte layer in the first direction; and the third cross-section is a cross-section located at a distance of 0 to 0.025 from the center of the first solid electrolyte layer (the midpoint between one end and the other end) in the first direction towards one end and the other end, respectively. It should be noted that, in Example 1, the arithmetic mean of the full width at half maximum (FWHM) of the peaks in sections 1 through 3 is 68.7 cm. -1 In Example 2, it is 66.2 cm. -1 In Example 3, it was 67.1 cm. -1 In Example 4, it is 66.4 cm. -1 In Example 5, it is 67.5 cm. -1 In Comparative Example 1, it was 77.4 cm. -1 .

[0155] [Table 1]

[0156]

[0157] <Evaluation>

[0158] rate of change of capacitance

[0159] At 20°C, the initial capacitance C0 (μF) of each electrolytic capacitor was measured at a frequency of 120 kHz using a 4-terminal LCR meter. The arithmetic mean of the 20 electrolytic capacitors was then calculated. Next, an accelerated test was conducted by applying the rated voltage to each electrolytic capacitor for 3000 hours at 145°C. Then, following the same procedure as for the initial capacitance, the capacitance C1 (μF) after the accelerated test was measured at 20°C, and the arithmetic mean of the 20 electrolytic capacitors was calculated. The capacitance change rate (%) was then calculated for each electrolytic capacitor using the following formula.

[0160] • Capacitance change rate (%) = (C0 - C1) / C0 × 100

[0161] For each example of electrolytic capacitor, the rate of change of capacitance (%) is shown in Table 2 below.

[0162] [Table 2]

[0163]

[0164] As shown in Table 2, in the electrolytic capacitors of Examples 1-5, the capacitance change rate is less than 10%, meaning the capacitance retention rate is greater than 90%. In contrast, in the electrolytic capacitor of Comparative Example 1, the capacitance change rate is greater than 99%, meaning the capacitance retention rate is less than 1%. Therefore, in the electrolytic capacitors of Examples 1-5, the conductive polymer contained in the first solid electrolyte layer formed between the cathode lead layer and the dielectric layer has high crystallinity, thus sufficiently maintaining the capacitance. In contrast, in the electrolytic capacitor of Comparative Example 1, the conductive polymer contained in the first solid electrolyte layer has reduced crystallinity, thus failing to sufficiently maintain the capacitance. Furthermore, it is also evident that maintaining a distance of 0.18 mm or more between the end of the separating component and the end of the first solid electrolyte layer can improve the capacitance retention rate.

[0165] (Experimental Examples 1-12)

[0166] When the length between the first end portion of the first solid electrolyte layer and the second end portion of the separation member opposite to the first end portion in the first direction is set as LA, and the length of the anode body is set as LB, the ratio of LA to LB (LA / LB×100) is varied as shown in Table 3 below, and electrolytic capacitors for Test Examples 1 to 12 are prepared. Then, the capacitance retention rate of the electrolytic capacitors for Test Examples 1 to 12 is evaluated for the same operation as described above. The results are shown in Table 3 below.

[0167] [Table 3]

[0168]

[0169] As shown in Table 3, except for Example 10 where the LA / LB ratio (LA / LB×100) was 2.4%, the capacitance change rate was less than 10%, meaning the capacitance retention rate was greater than 90%, which is a particularly good result. This indicates that, for example, by making LA / LB×100 2.8% or higher, the capacitance can be maintained particularly well. That is, it can be seen that the conductive polymer contained in the first solid electrolyte layer formed between the cathode lead-out layer and the dielectric layer exhibits particularly high crystallinity.

[0170] Industrial availability

[0171] The electrolytic capacitor of the present invention can be used in applications requiring sufficient suppression of oxidative degradation of conductive polymers.

[0172] Explanation of reference numerals in the attached figures

[0173] 100: Electrolytic capacitor

[0174] 110: Capacitor Components

[0175] 11: Anode

[0176] 12: Dielectric layer

[0177] 13: Solid electrolyte layer

[0178] 14: Cathode lead-out layer

[0179] 141: Carbon layer

[0180] 142: Metal paste layer

[0181] 15: Separation Components

[0182] 120A: Anode lead frame

[0183] 120B: Cathode lead frame

[0184] 130: Sealing resin

Claims

1. An electrolytic capacitor comprising a capacitor element, the capacitor element comprising: an anode body extending along a first direction, a dielectric layer covering at least a portion of the anode body, a solid electrolyte layer comprising a conjugated polymer and covering at least a portion of the dielectric layer, and a cathode lead-out layer covering at least a portion of the solid electrolyte layer. The anode body has, along the first direction: a solid electrolyte forming portion on which the solid electrolyte layer is formed in at least a portion, an anode portion, and a separation portion disposed between the solid electrolyte forming portion and the anode portion. The conjugated polymer system includes conductive polymers. When the solid electrolyte layer formed between the cathode lead-out layer and the dielectric layer is designated as the first solid electrolyte layer, in the Raman spectrum of the first solid electrolyte layer, when the peak at half maximum (FWHM) of the peak attributable to the C-C stretching vibration originating from the conjugated polymer is fitted using the Lorentz function, the peak at half maximum (FWHM) is 50 cm⁻¹. -1 Above and 70cm -1 the following.

2. The electrolytic capacitor according to claim 1, wherein, The solid electrolyte forming section has a second solid electrolyte layer formed on the separation section side further than the first solid electrolyte layer. The thickness L of the second solid electrolyte layer C2 Relative to the thickness L of the first solid electrolyte layer C1 The ratio of L C2 / L C1 Satisfy L C2 / L C1 A relationship of ≤1 / 10.

3. The electrolytic capacitor according to claim 1, wherein, The solid electrolyte forming section has only a first solid electrolyte layer.

4. The electrolytic capacitor according to any one of claims 1 to 3, wherein, The separating section has a separating component. The first solid electrolyte layer and the end portion of the separation component facing each other in the first direction are spaced at least 0.18 mm apart.

5. The electrolytic capacitor according to any one of claims 1 to 3, wherein, The separating section has a separating component. In the first direction, the length of the interval between the first end portion of the first solid electrolyte layer and the second end portion of the separation member opposite to the first end portion is 2.8% or more relative to the length of the anode body.

6. The electrolytic capacitor according to any one of claims 1 to 3, wherein, The first solid electrolyte layer is composed of at least two layers of solid electrolyte layers stacked together.

7. The electrolytic capacitor according to claim 6, wherein, Of the at least two solid electrolyte layers, the outermost solid electrolyte layer is formed by electrolytic polymerization.

8. The electrolytic capacitor according to claim 2, wherein, The second solid electrolyte layer is formed solely through electrolytic polymerization.

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