Patent Application
20250104926
The present disclosure relates to an electrolytic capacitor and a method for manufacturing an electrolytic capacitor.
An electrolytic capacitor that includes a wound body including an anode foil, a separator, and a cathode foil is known. An example of such an electrolytic capacitor includes a conductive polymer layer disposed inside the wound body. The conductive polymer layer is formed by impregnating the wound body with a dispersion liquid that contains particles of a conductive polymer, for example.
The dispersion liquid containing particles of a conductive polymer has high viscosity due to containing the particles. Accordingly, even if the wound body is impregnated with the dispersion liquid, it may not be possible to form the conductive polymer layer sufficiently inside the wound body. Insufficient formation of the conductive polymer layer may result in a reduction in an initial capacity, an increase in the equivalent series resistance (ESR), and a reduction in the reliability, for example. Also, if a dielectric film formed on a surface of the anode foil is covered by dense conductive polymer particles, an electrolyte solution is unlikely to come into contact with a surface of the dielectric layer. Consequently, the electrolyte solution does not sufficiently function to form a dielectric layer (oxide film), and this may result in an increase of a leakage current or the occurrence of a short circuit, for example.
PTL 1 (International Publication WO 2020/158780) discloses “a method for producing an electrolytic capacitor, the method including steps of: preparing an electrode foil: preparing a first conductive polymer dispersion containing a first conductive polymer component and a first dispersion medium: forming a first conductive polymer layer containing the first conductive polymer component by applying the first conductive polymer dispersion to a surface of the electrode foil by a coating method, and then at least partially removing the first dispersion medium; and fabricating a capacitor element using the electrode foil having the first conductive polymer layer.”
PTL 2 (International Publication WO 2020/158783) discloses “a method for producing an electrolytic capacitor, the method including steps of: preparing an anode foil that includes a dielectric layer, a cathode foil, and a fiber structure: preparing a conductive polymer dispersion liquid that contains a conductive polymer component and a dispersion medium: producing a separator by applying the conductive polymer dispersion liquid to the fiber structure and then removing at least a portion of the dispersion medium; and producing a capacitor element by sequentially stacking the anode foil, the separator, and the cathode foil, wherein the dispersion medium contains water, the fiber structure contains a synthetic fiber in an amount of 50% by mass or more, and the fiber structure has a density of 0.2 g/cm3 or more and less than 0.45 g/cm3.”
An object of the present disclosure is to provide a method for manufacturing an electrolytic capacitor that includes a conductive polymer layer and has excellent characteristics.
While novel features of the present invention are set forth in the appended claims, both the configuration and content of the present invention, as well as other objects and features of the present invention, will be better understood from the following detailed description given with reference to the drawings.
An aspect of the present disclosure relates to a method for manufacturing an electrolytic capacitor. The manufacturing method is a method for manufacturing an electrolytic capacitor including an anode foil having a dielectric layer formed on a surface thereof, a cathode foil, and a separator, and the method includes, in the following order: a polymer layer formation step of forming a conductive polymer layer containing a conductive polymer component on the separator and at least one surface selected from a surface of the dielectric layer and a surface of the cathode foil; a stacked body formation step of forming a stacked body by stacking the anode foil, the cathode foil, and the separator such that the separator is disposed between the anode foil and the cathode foil: a liquid application step of impregnating the conductive polymer layer included in the stacked body with a liquid that includes water and an organic compound that does not boil at 100° C. under 1 atm; a removal step of removing a portion of the liquid with which the conductive polymer layer has been impregnated, such that the organic compound remains in the conductive polymer layer; and an impregnation step of impregnating the stacked body subjected to the removal step with a liquid component.
Another aspect of the present disclosure relates to an electrolytic capacitor. The electrolytic capacitor includes: a stacked body including an anode foil having a dielectric layer formed on a surface thereof, a cathode foil, and a separator; and a liquid component with which the stacked body is impregnated, wherein the stacked body includes a conductive polymer layer formed on the separator and at least one surface selected from a surface of the dielectric layer and a surface of the cathode foil, the conductive polymer layer includes a mixed region in which a first conductive polymer layer formed on the at least one surface and a second conductive polymer layer formed on the separator are mixed, and at least one selected from the group consisting of glycols, glycerin, polyglycerins, and sugar alcohols is present in the mixed region.
According to the present disclosure, it is possible to obtain an electrolytic capacitor that includes a conductive polymer layer and has excellent characteristics.
The following describes an example embodiment of the present invention, but the present invention is not limited to the following example. In the following description, specific numerical values and materials are given as examples in some cases, but other numerical values and other materials may also be applied as long as the invention according to the present disclosure can be implemented. In the specification, the expression “a numerical value A to a numerical value B” includes the numerical value A and the numerical value B, and can be read as “the numerical value A or more and the numerical value B or less”. In the following description, if lower and upper limits of numerical values regarding specific physical properties or conditions are exemplified, any of the exemplified lower limits and any of the exemplified upper limits can be combined as desired as long as the lower limit is not equal to or greater than the upper limit.
A manufacturing method according to an embodiment of the present disclosure is a method for manufacturing an electrolytic capacitor including an anode foil having a dielectric layer formed on a surface thereof, a cathode foil, and a separator. Hereinafter, the manufacturing method may also be referred to as a “manufacturing method (M)”. The manufacturing method (M) includes a polymer layer formation step, a stacked body formation step, a liquid application step, a removal step, and an impregnation step in this order. The following describes these steps.
The polymer layer formation step is a step of forming a conductive polymer layer that contains a conductive polymer component on the separator and at least one surface selected from a surface of the dielectric layer (the dielectric layer on the surface of the anode foil) and a surface of the cathode foil. Hereinafter, the at least one surface may be referred to as “the at least one surface(S)” or “the surface(S)”.
The polymer layer formation step may include a step (a) and a step (b). The step (a) is a step of applying an application liquid that contains the conductive polymer component and a liquid medium to the at least one surface(S) and the separator. The step (b) is a step of forming the conductive polymer layer on the at least one surface(S) and the separator by removing at least a portion of the liquid medium from the applied application liquid. The liquid medium may include water or may be water. The following describes the steps (a) and (b).
In the step (a), the application liquid may be applied to a surface of the dielectric layer and the separator or may be applied to a surface of the cathode foil and the separator. Alternatively, the application liquid may be applied to a surface of the dielectric layer, a surface of the cathode foil, and the separator. As necessary, the application liquid is applied to dielectric layers formed on both surfaces of the anode foil and applied to both surfaces of the cathode foil. A conductive polymer layer is formed in regions to which the application liquid is applied.
Examples of the conductive polymer component will be described later. The conductive polymer component may be dispersed in the state of particles in the application liquid.
There is no limitation on the method for applying the application liquid, and a known method may be used to apply the application liquid. For example, a method that uses a coater may be used, the application liquid may be sprayed, or an object to which the application liquid is to be applied may be immersed in the application liquid. Examples of the method that uses a coater include a gravure coating method and a die coating method. Note that methods for applying the application liquid to the separator include a method of impregnating the separator with the application liquid. The application liquid applied to the separator permeates the inside of the separator, and the conductive polymer layer can be formed in an entire region of the separator in its thickness direction.
There is no limitation on the method for removing the liquid medium in the step (b). The liquid medium may be removed through heating and/or by reducing a pressure, and it is preferable to perform at least heating. 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 within a range from 100° C. to 200° C. The heating time is not particularly limited as long as a portion of the liquid medium can be removed appropriately. For example, the heating time is within a range from 5 to 60 minutes.
Note that the conductive polymer layer can be formed separately on each member. Accordingly, the application liquid may be applied to a member (step (a)) after another member is dried (step (b)). For example, after the application liquid is applied to the surface(S) (step (a)) and the surface(S) is dried (step (b)), the application liquid may be applied to the separator (step (a)) and the separator may be dried (step (b)). Likewise, the steps (a) and (b) for forming the conductive polymer layer on the anode foil (on the dielectric layer), the steps (a) and (b) for forming the conductive polymer layer on the cathode foil, and the steps (a) and (b) for forming the conductive polymer layer on the separator can be performed in a suitable order.
In the polymer layer formation step, the conductive polymer layer may be formed on the surface of the dielectric layer (the dielectric layer on the anode foil), the surface of the cathode foil, and the separator. According to this configuration, the conductive polymer layer can be formed in such a manner as to be continuous from the dielectric layer to the cathode foil facing the dielectric layer.
In the following description, the conductive polymer layer formed on the surface(S) may be referred to as a “first conductive polymer layer”, and the conductive polymer layer formed on the separator may be referred to as a “second conductive polymer layer”. The second conductive polymer layer can be formed on a surface of fibers or a microporous film constituting the separator.
The first conductive polymer layer and the second conductive polymer layer may be constituted of the same conductive polymer component or may contain different conductive polymer components. The first conductive polymer layer formed on the anode foil (on the dielectric layer), the first conductive polymer layer formed on the cathode foil, and the second conductive polymer layer may be constituted of the same conductive polymer component or may contain different conductive polymer components. In a preferred example, these layers contain the same conductive polymer component.
When the first conductive polymer layer is formed on a surface of the anode foil (or the cathode foil), it is preferable to form the first conductive polymer layer in 80% or more (e.g., 90% or more) of the area of the surface on which the first conductive polymer layer is formed. The first conductive polymer layer is preferably formed on an entire surface of the electrode foil (the anode foil or the cathode foil) that contributes to the capacitance of a capacitor element, out of surfaces of the electrode foil. The area of the second conductive polymer layer formed on the separator is preferably 80% or more (e.g., 90% or more) of the area of the separator, and the second conductive polymer layer may be formed on the entire separator. Here, the area of a surface of an electrode foil (the anode foil or the cathode foil) is an area calculated without irregularities in the surface being taken into account, and can be calculated from an external shape of the electrode foil. When the first conductive polymer is formed on both surfaces of an electrode foil, the area of the surfaces on which the first conductive polymer is formed is the sum of the areas of both surfaces.
The mass of the first conductive polymer layer per unit area may be 0.01 mg/cm2 or more, or 0.02 mg/cm2 or more, and may be 0.5 mg/cm2 or less, or 0.3 mg/cm2 or less. When the mass is 0.1 mg/cm2 or more, the conductive polymer layer can be formed more uniformly. Note that, when the first conductive polymer layer is formed on both surfaces of an electrode foil, the above-described mass per unit area is the mass of the first conductive polymer layer formed on a surface of the electrode foil.
The mass of the second conductive polymer layer per unit area may be 0.02 mg/cm2 or more, or 0.05 mg/cm2 or more, and may be 2.0 mg/cm2 or less, or 1.0 mg/cm2 or less. When the mass is 0.3 mg/cm2 or more, the conductive polymer layer can be formed more uniformly.
Note that the mass of the conductive polymer layer per unit area can be calculated using the following method. First, five samples each having a predetermined area are cut out from the member (the electrode foil or the separator) prior to the formation of the conductive polymer layer, and masses of the five samples are measured. Also, five samples each having the predetermined area are cut out from the member (the electrode foil or the separator) on which the conductive polymer layer has been formed, and masses of the samples are measured. The mass of the conductive polymer layer per unit area is calculated from the predetermined area and a difference between a sum of the masses of the five samples after the formation of the conductive polymer layer and a sum of the masses of the five samples prior to the formation of the conductive polymer layer.
The stacked body formation step is a step of forming a stacked body including the conductive polymer layer by stacking the anode foil, the cathode foil, and the separator such that the separator is disposed between the anode foil and the cathode foil.
There is no limitation on the method for forming the stacked body, and a known method may be used to form the stacked body. The stacked body may be a wound body. In this case, the wound body may be formed by winding together the anode foil, the cathode foil, and the separator such that the separator is disposed between the anode foil and the cathode foil in the stacked body formation step. In the wound body, the anode foil, the cathode foil, and the separator are stacked in a radial direction of the wound body.
The stacked body may be formed by stacking a flat anode foil, a flat cathode foil, and a flat separator in one direction. For example, it is also possible to form the stacked body by stacking a plurality of anode foils, a plurality of cathode foils, and a plurality of separators in one direction. In a typical example of such a stacked body, the anode foils and the cathode foils are alternately disposed, and the separators are disposed between the anode foils and the cathode foils.
The liquid application step is a step of impregnating the conductive polymer layer included in the stacked body with a liquid that contains water and an organic compound that does not boil at 100° C. under 1 atm (101325 Pa). Hereinafter, the organic compound and the liquid may also be referred to as the “organic compound (C)” and the “liquid(S)”. A major component (content: 50% by mass or more) of the liquid(S) may be water.
There is no limitation on the method for impregnating the conductive polymer layer with the liquid(S). For example, it is possible to impregnate the conductive polymer layer with the liquid(S) by immersing at least a portion of the stacked body in the liquid(S). It is possible to improve adhesion between the first conductive polymer layer and the second conductive polymer layer by performing the liquid application step.
As described above, the liquid(S) contains water and the organic compound (C). The liquid(S) may be constituted of only water and the organic compound (C), or may contain another component. An organic compound that dissolves well in water can be preferably used as the organic compound (C). The organic compound (C) may be a compound that is miscible with water. Examples of the organic compound (C) include compounds that are used as organic solvents. Examples of the organic compound (C) include polyhydric alcohols that have two or more hydroxyl groups.
The liquid(S) may contain a conductive polymer, but does not necessarily need to contain a conductive polymer. The liquid(S) acts on the conductive polymer layer, and accordingly, it is preferable that the liquid(S) does not substantially contain a conductive polymer. For example, the content of a conductive polymer contained in the liquid(S) may be less than 0.5% by mass, or less than 0.1% by mass. When the liquid(S) contains a conductive polymer component, the conductive polymer component contained in the conductive polymer layer and the conductive polymer component contained in the liquid(S) may be the same as each other or different from each other.
In the present specification, the term “boiling point” means a boiling point under 1 atm unless otherwise stated. Examples of the organic compound (C) include organic compounds that have a boiling point higher than 100° C. When the organic compound (C) has a boiling point, the boiling point may be 110° C. or higher, 150° C. or higher, or 200° C. or higher, and may be 400° C. or lower, 300° C. or lower, 250° C. or lower, or 200° C. or lower. The boiling point may be within a range from 110° C. to 400° C. (e.g., from 150° C. to 350° C.).
Examples of the organic compound (C) include polyhydric alcohols, sulfolane, γ-butyrolactone, and borate esters. The organic compound (C) may include at least one selected from the group consisting of polyhydric alcohols, sulfolane, γ-butyrolactone, and borate esters, and may also be at least one selected from the group. The organic compound (C) may include at least one selected from the group consisting of glycols, glycerins, sugar alcohols, sulfolane, γ-butyrolactone, and borate esters, and may also be at least one selected from the group.
Examples of the polyhydric alcohols include glycols, glycerins, and sugar alcohols. Examples of the glycols include ethylene glycol, diethylene glycol, triethylene glycol, polyalkylene glycol (e.g., polyethylene glycol), and polyoxyethylene polyoxypropylene glycol (ethylene oxide-propylene oxide copolymer). Examples of the glycerins include glycerin and polyglycerins. Examples of the sugar alcohols include mannitol, xylitol, sorbitol, erythritol, and pentaerythritol.
The organic compound (C) may be a protic solvent. Examples of the protic solvent will be described later. Glycols (e.g., ethylene glycol) are preferably used as the organic compound (C) because a high effect can be obtained.
The water content in the liquid(S) is 40% by mass or more, for example, and may be 50% by mass or more, 70% by mass or more, 90% by mass or more, or 95% by mass or more. The content is preferably 99% by mass or less, or 98% by mass or less, and may be 95% by mass or less, 90% by mass or less, 80% by mass or less, or 50% by mass or less. The content may be within a range from 40 to 99% by mass, a range from 50 to 99% by mass, a range from 70 to 99% by mass, or a range from 90 to 99% by mass. The upper limit of any of these ranges may be replaced with 98% by mass, 95% by mass, 90% by mass, 80% by mass, or 50% by mass as long as the lower limit is not equal to or greater than the upper limit.
The content of the organic compound (C) in the liquid(S) may be 1% by mass or more, 2% by mass or more, 3% by mass or more, 5% by mass or more, 10% by mass or more, or 20% by mass or more. The content may be 60% by mass or less, 50% by mass or less, 40% by mass or less, or 30% by mass or less. The content may be within a range from 1 to 60% by mass, a range from 2 to 60% by mass, a range from 3 to 60% by mass, a range from 5 to 60% by mass, or a range from 10 to 60% by mass. The upper limit of any of these ranges may be replaced with 50% by mass, 30% by mass, 25% by mass, or 20% by mass. The content is preferably within a range from 2 to 50% by mass, and more preferably within a range from 5 to 50% by mass.
A ratio between the water content (% by mass) and the content (% by mass) of the organic compound (C) in the liquid(S) may be within a range from 99:1 (or 98:2) to 50:50 (or 60:40).
The removal step is a step of removing a portion of the liquid(S) with which the conductive polymer layer has been impregnated, such that the organic compound (C) remains in the conductive polymer layer. There is no particular limitation on the period from when the liquid application step is performed to when the removal step is performed, and the removal step may be performed immediately after the liquid application step. Alternatively, the removal step may be performed after a period within a range from 1 to 360 minutes (e.g., a range from 5 to 180 minutes) has elapsed from when the liquid application step is performed.
If the liquid(S) is completely removed, the conductive polymer layer shrinks significantly. If the conductive polymer layer shrinks significantly, the equivalent series resistance (ESR) of the electrolytic capacitor increases. Also, if the conductive polymer layer shrinks significantly and the dielectric film formed on the surface of the anode foil is covered by a dense conductive polymer, a liquid component (L), which will be described later, is unlikely to come into contact with the surface of the dielectric layer. Consequently, the liquid component (L) does not sufficiently function to form a dielectric layer (oxide film), and this may result in an increase of a leakage current or the occurrence of a short circuit, for example.
In the manufacturing method (M), the liquid(S) is removed such that the organic compound (C) remains in the conductive polymer layer. As a result, it is possible to manufacture an electrolytic capacitor that has a low ESR and high reliability, and of which a leakage current is suppressed.
It is preferable that the liquid application step and the removal step are performed such that the mass of the organic compound (C) contained in the conductive polymer layer becomes larger than the mass of water contained in the conductive polymer layer in the removal step. That is to say, it is preferable that, after the removal step is performed and before another step is performed, the mass of the organic compound (C) contained in the conductive polymer layer is larger than the mass of water contained in the conductive polymer layer. Characteristics of the electrolytic capacitor deteriorate with an increase in the amount of water remaining in the conductive polymer layer. Therefore, it is preferable to remove a portion of the liquid(S) in the removal step such that the amount of water remaining in the conductive polymer layer decreases.
The liquid(S) may be removed through heating and/or by reducing a pressure, and it is preferable to perform at least heating. When heating is performed, it is preferable to remove a portion of the liquid(S) by heating the stacked body at a temperature higher than or equal to 100° C. When the stacked body is heated at a temperature higher than or equal to 100° C., it is possible to rapidly remove water contained in the liquid(S). The heating temperature is preferably a temperature at which the organic compound (C) does not boil and decompose. If the organic compound (C) does not have a definite boiling point, it is preferable to heat the stacked body at a temperature at which the organic compound (C) does not evaporate very much and does not decompose. The heating temperature may be 100° C. or higher, 120° C. or higher, or 140° C. or higher, and may be 250° C. or lower, 200° C. or lower, or 160° C. or lower. The heating temperature may be within a range from 100° C. to 200° C. (e.g., a range from 100° C. to 160° C.). The heating time is not particularly limited as long as a portion of the liquid(S) can be removed appropriately. For example, the heating time is within a range from 5 to 60 minutes.
The liquid application step and the removal step may be performed such that a ratio Wc/Wp between a mass Wc of the organic compound (C) remaining in the conductive polymer layer and a mass Wp of the conductive polymer component contained in the conductive polymer layer is 1.0 or more and 20 or less. The ratio Wc/Wp may be 1.0 or more, 1.2 or more, or 2.0 or more, and may be 20 or less, or 18 or less. The ratio Wc/Wp may be 1.0 or more and 20 or less, 1.2 or more and 18 or less, or 2.0 or more and 18 or less. When the ratio Wc/Wp is 2.0 or more and 18 or less, it is possible to obtain an electrolytic capacitor that has particularly excellent characteristics. Wc/Wp can be increased by increasing the content of the organic compound (C) in the liquid(S) or increasing the application amount of the liquid(S). Methods for measuring Wc and Wp will be described later.
In the removal step, a portion of the liquid(S) is removed such that a ratio Ww/Wc between a mass Ww of water contained in the conductive polymer layer and the mass Wc of the organic compound (C) contained in the conductive polymer layer is less than 1. Ww/Wc may be 0 or more, 0.001 or more, 0.1 or more, or 0.2 or more, and may be 0.9 or less, 0.8 or less, 0.5 or less, 0.2 or less, 0.1 or less, or 0.005 or less. Ww can be measured using Karl Fischer titration. Ww/Wc can be reduced by increasing the content of the organic compound (C) in the liquid(S), reducing the water content in the liquid(S), or performing the removal step under conditions where water evaporates preferentially, for example.
The impregnation step is a step of impregnating the stacked body (e.g., the conductive polymer layer in the stacked body) subjected to the removal step with a liquid component. The liquid component may be hereinafter referred to as a “liquid component (L)”. There is no limitation on the method for impregnating the stacked body with the liquid component (L). For example, it is possible to impregnate the stacked body with the liquid component (L) by immersing at least a portion of the stacked body in the liquid component (L). Examples of the liquid component (L) will be described later.
Through the steps described above, a capacitor element including the conductive polymer layer and the liquid component is formed. Thereafter, the capacitor element is enclosed in an exterior body as necessary. Thus, an electrolytic capacitor is manufactured. Note that the manufacturing method (M) may also include a step other than the above-described steps as necessary.
The conductive polymer layer may include the first conductive polymer layer formed on the at least one surface(S) described above and the second conductive polymer layer formed on the separator. In this case, the conductive polymer layer in the stacked body subjected to the impregnation step may include a mixed region in which the first conductive polymer layer and the second conductive polymer layer are mixed.
In the removal step of the manufacturing method (M), a portion of the liquid(S) is removed such that the organic compound (C) remains in the conductive polymer layer. Therefore, excessive shrinkage of the conductive polymer component is suppressed, and it is possible to form the mixed region in which the first conductive polymer layer and the second conductive polymer layer are mixed. It is possible to reduce the ESR of the capacitor element by forming the mixed region.
The application liquid used in the polymer layer formation step contains the conductive polymer component and the liquid medium. The application liquid may also contain another component as necessary. The liquid medium may include water or may be water. The liquid medium may include the organic compound (C). The application liquid may be a dispersion liquid in which particles of the conductive polymer component are dispersed.
The conductive polymer component includes a conductive polymer, and may be constituted of only the conductive polymer. Alternatively, the conductive polymer component may include a conductive polymer and a dopant.
Examples of the conductive polymer include polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, and derivatives thereof. Examples of the derivatives include polymers that include polypyrrole, polythiophene, polyfuran, polyaniline, or polyacetylene as the basic skeleton. Examples of derivatives of polythiophene include poly(3,4-ethylenedioxythiophene). Any one of these conductive polymers may be used alone, or two or more of these may be used in combination. Also, the conductive polymer may be a copolymer of two or more monomers. The weight average molecular weight of the conductive polymer is not particularly limited, and may be within a range from 1000 to 100000, for example. A preferred example of the conductive polymer is poly(3,4-ethylenedioxythiophene) (PEDOT).
The conductive polymer may be doped with a dopant. From the standpoint of suppressing de-doping from the conductive polymer, it is preferable to use a polymer dopant as the dopant. Examples of the polymer dopant include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polyacryl sulfonic acid, polymethacryl sulfonic acid, poly(2-acrylamido-2-methylpropanesulfonic acid), polyisoprene sulfonic acid, and polyacrylic acid. Any one of these may be used alone, or two or more of these may be used in combination. At least some of these may be added in the form of a salt. A preferred example of the dopant is polystyrene sulfonic acid (PSS).
In the electrolytic capacitor according to the present disclosure, the dopant may be a dopant that contains an acidic group or a polymer dopant that contains an acidic group. Examples of the acidic group include a sulfonic acid group and a carboxyl group. The polymer dopant containing an acidic group is a polymer in which at least some constituent units contain an acidic group. Examples of such a polymer dopant include the polymer dopants described above.
The weight average molecular weight of the dopant is not particularly limited. From the standpoint of facilitating formation of a uniform conductive polymer layer, the weight average molecular weight of the dopant may be within a range from 1000 to 100000.
The dopant may be polystyrene sulfonic acid, and the conductive polymer may be poly(3,4-ethylenedioxythiophene). That is to say, the conductive polymer component may be poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonic acid.
When the conductive polymer doped with the dopant is used, the pH of the application liquid is preferably less than 7.0 in order to suppress de-doping of the dopant, and may be 6.0 or less, or 5.0 or less. The pH of the application liquid may be 1.0 or more, or 2.0 or more.
The conductive polymer component may be present in the state of particles in the application liquid. In a particle size distribution of the particles of the conductive polymer component on the volume basis, the mode of the particle size may be 10 nm or more, or 20 nm or more, and may be 1000 nm or less, 500 nm or less, 200 nm or less, or 100 nm or less. The particle size distribution on the volume basis can be determined with use of a laser diffraction/scattering particle size distribution measurement device.
The above-described mode of the particle size of the particles of the conductive polymer component may be within a range from 20 nm to 200 nm (e.g., from 20 nm to 100 nm). In the particle size distribution on the volume basis, the percentage of particles having a particle size within a range from 20 nm to 100 nm may be 90% or more of all the particles on the volume basis. When the mode and the percentage are within these ranges, it is easy to form the conductive polymer layer containing the conductive polymer component in pores of the members (the electrode foil and the separator).
The water content in the application liquid may be 50% by mass or more, 80% by mass or more, 90% by mass or more, 96% by mass or more, or 97% by mass or more. The content may be 99.5% by mass or less. The content may be within a range from 50 to 99.5% by mass, a range from 96 to 99.5% by mass, or a range from 97 to 99.5% by mass.
The content of the conductive polymer component in the application liquid may be 0.5% by mass or more, or 1.0% by mass or more, and may be 4.0% by mass or less, 3.0% by mass or less, or 2.0% by mass or less. The content may be within a range from 0.5 to 4.0% by mass, or a range from 1.0 to 4.0% by mass. The upper limit of any of these ranges may be replaced with 3.0% by mass, or 2.0% by mass. The content is preferably within a range from 1.0 to 3.0% in terms of achieving excellent physical properties of the application liquid, excellent stability of the physical properties over time, and a good balance between the ESR of the electrolytic capacitor and the cost. When the application liquid contains a dopant, the mass of the dopant is included in the mass of the conductive polymer component.
The mass of the dopant contained in the application liquid is not particularly limited, and may be within a range from 0.1 to 5 times (e.g., from 0.5 to 3 times) the mass of the conductive polymer contained in the application liquid.
The water content and the content of the conductive polymer component described above can be combined suitably unless no contradiction arises. An example of the application liquid may satisfy one, two, three, or four conditions suitably selected from the following conditions (1) to (4) or satisfy all the conditions.
The application liquid may satisfy the conditions (2) and (3) described above. When the conditions (2) and (3) are satisfied, it is possible to form a conductive polymer layer that has high conductivity.
Examples of the liquid component (L) used in the impregnation step include a nonaqueous solvent and an electrolyte solution. It is possible to use an electrolyte solution that contains a nonaqueous solvent and a solute dissolved in the nonaqueous solvent. In the present specification, the liquid component (L) may be a component that is liquid at room temperature (25° C.) or a component that is liquid at a temperature at which the electrolytic capacitor is used.
The nonaqueous solvent used in the liquid component (L) may be an organic solvent, an ionic liquid, or a protic solvent. Examples of the nonaqueous solvent include polyhydric alcohols such as ethylene glycol and propylene glycol, cyclic sulfones such as sulfolane (SL), lactones such as γ-butyrolactone (γBL), 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.
It is also possible to use a polymer-based solvent as the nonaqueous solvent. Examples of the polymer-based solvent include polyalkylene glycol, derivatives of polyalkylene glycol, and compounds in which at least one hydroxyl group of a polyhydric alcohol is substituted with polyalkylene glycol (including derivatives thereof). Specific examples of the polymer-based solvent 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. Examples of the polymer-based solvent further include ethylene glycol-propylene glycol copolymer, ethylene glycol-butylene glycol copolymer, and propylene glycol-butylene glycol copolymer. A nonaqueous solvent may be used alone, or a mixture of two or more nonaqueous solvents may be used.
The liquid component (L) may contain the nonaqueous solvent and a base component (base) dissolved in the nonaqueous solvent. Also, the liquid component (L) may contain the nonaqueous solvent and a base component and/or an acid component (acid) dissolved in the nonaqueous solvent.
As the acid component, it is possible to use a polycarboxylic acid and a monocarboxylic acid. Examples of the polycarboxylic acid include aliphatic polycarboxylic acid ([saturated polycarboxylic acid such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,6-decanedicarboxylic acid, and 5,6-decanedicarboxylic acid]; [unsaturated polycarboxylic acid such as maleic acid, fumaric acid, and itaconic acid]), aromatic polycarboxylic acid (e.g., phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, and pyromellitic acid), alicyclic polycarboxylic acid (e.g., cyclohexane-1,2-dicarboxylic acid and cyclohexene-1,2-dicarboxylic acid).
Examples of the monocarboxylic acid include aliphatic monocarboxylic acid (having 1 to 30 carbon atoms) ([saturated monocarboxylic acid such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, lauryl acid, myristic acid, stearic acid, and behenic acid]; [unsaturated monocarboxylic acid such as acrylic acid, methacrylic acid, and oleic acid]), aromatic monocarboxylic acid (e.g., benzoic acid, cinnamic acid, and naphthoic acid), and oxycarbonic acid (e.g., salicylic acid, mandelic acid, and resorcinol acid).
Among these, maleic acid, phthalic acid, benzoic acid, pyromellitic acid, and resorcinol acid are thermally stable and preferably used.
An inorganic acid may also be used as the acid component. Representative examples of the inorganic acid include phosphoric acid, phosphorous acid, hypophosphorous acid, alkyl phosphate, boric acid, borofluoric acid, tetrafluoroboric acid, hexafluorophosphoric acid, benzenesulfonic acid, and naphthalenesulfonic acid. It is also possible to use a composite compound of an organic acid and an inorganic acid as the acid component. Examples of such a composite compound include borodiglycolic acid, borodisuccinic acid, and borodisalicylic acid.
The base component may be a compound that has an alkyl-substituted amidine group such as imidazole compound, benzoimidazole compound, or alicyclic amidine compound (pyrimidine compound or imidazoline compound). Specifically, the base component is preferably 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-heptylimidazoline, 1-methyl-2-(3′heptyl) imidazoline, 1-methyl-2-dodecylimidazoline, 1,2-dimethyl-1,4,5,6-tetrahydropyrimidine, 1-methylimidazole, or 1-methylbenzoimidazole. With use of these, it is possible to obtain a capacitor that has excellent impedance performance.
A quaternary salt of a compound that has an alkyl-substituted amidine group may also be used as the base component. Examples of such a base component include an imidazole compound, a benzoimidazole compound, and an alicyclic amidine compound (a pyrimidine compound or an imidazoline compound), which are quaternized by an alkyl group or arylalkyl group having 1 to 11 carbon atoms. Specifically, the base component is preferably 1-methyl-1,8-diazabicyclo [5,4,0]undecene-7,1-methyl-1,5-diazabicyclo [4,3,0]nonene-5,1,2,3-trimethylimidazolinium, 1,2,3,4-tetramethylimidazolinium, 1,2-dimethyl-3-ethyl-imidazolinium, 1,3,4-trimethyl-2-ethylimidazolinium, 1,3-dimethyl-2-heptylimidazolinium, 1,3-dimethyl-2-(3′heptyl) imidazolinium, 1,3-dimethyl-2-dodecylimidazolinium, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidium, 1,3-dimethylimidazolium, 1-methyl-3-ethylimidazolium, or 1,3-dimethylbenzoimidazolium. With use of these, it is possible to obtain a capacitor that has excellent impedance performance.
It is also possible to use a tertiary amine as the base component. Examples of the tertiary amine include trialkylamines (e.g., trimethylamine, dimethylethylamine, methyldiethylamine, triethylamine, dimethyl-n-propylamine, dimethylisopropylamine, methylethyl-n-propylamine, methylethylisopropylamine, diethyl-n-propylamine, diethylisopropylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, and tri-tert-butylamine), and phenyl group-containing amines (e.g., dimethylphenylamine, methylethylphenylamine, and diethylphenylamine). Among these, trialkylamines are preferable in terms of achieving high conductivity, and it is more preferable that the base component includes at least one selected from the group consisting of trimethylamine, dimethylethylamine, methyldiethylamine, and triethylamine. It is also possible to use secondary amines such as dialkylamines, primary amines such as monoalkylamine, or ammonia as the base component.
The liquid component (L) 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. For example, it is possible to use, as the organic salt, trimethylamine maleate, triethylamine borodisalicylate, ethyldimethylamine phthalate, mono-1,2,3,4-tetramethylimidazolinium phthalate, or mono-1,3-dimethyl-2-ethylimidazolinium phthalate.
In order to suppress de-doping of the dopant, the pH of the liquid component (L) may be less than 7.0, or 5.0 or less, and may be 1.0 or more, or 2.0 or more. The pH may be 1.0 or more and less than 7.0 (e.g., within a range from 2.0 to 5.0).
It is preferable that the liquid component (L) contains a protic solvent. When the liquid component (L) contains a protic solvent, a high effect can be obtained. The liquid component (L) may also contain a solvent other than the protic solvent, in addition to the protic solvent.
The protic solvent may include at least one selected from the group consisting of glycols, glycerin, polyglycerins, and sugar alcohols, and may also be at least one selected from the group. The protic solvent may be constituted of a single compound alone or may include a plurality of compounds.
The organic compound (C) and the liquid component (L) may include the same compound. For example, the organic compound (C) and the liquid component (L) may include the same protic solvent, the same polyhydric alcohol, the same glycol (e.g., ethylene glycol), or the same sugar alcohol.
Hereinafter, an electrolytic capacitor according to an embodiment of the present disclosure may be referred to as an “electrolytic capacitor (E)”. The electrolytic capacitor (E) can be manufactured using the manufacturing method (M). However, the electrolytic capacitor (E) may be manufactured using a method other than the manufacturing method (M). Matters described regarding the manufacturing method (M) can also be applied to the electrolytic capacitor (E), and therefore, redundant descriptions thereof may be omitted. Also, matters described regarding the electrolytic capacitor (E) may also be applied to the manufacturing method (M).
The electrolytic capacitor (E) includes: a stacked body including an anode foil having a dielectric layer formed on a surface thereof, a cathode foil, and a separator; and a liquid component with which the stacked body is impregnated. The liquid component is the liquid component (L) described above. The stacked body includes a conductive polymer layer that is formed on the separator and at least one surface(S) selected from a surface of the dielectric layer and a surface of the cathode foil. The conductive polymer layer includes a mixed region in which a first conductive polymer layer formed on the at least one surface(S) and a second conductive polymer layer formed on the separator are mixed.
The liquid component (L) is present in the conductive polymer layer (e.g., the mixed region). It is preferable that at least one selected from the group consisting of glycols, glycerin, polyglycerins, and sugar alcohols is present in the conductive polymer layer (e.g., the mixed region). This configuration improves the adhesion between the first conductive polymer layer and the second conductive polymer layer.
It is possible to make the conductive polymer layer (e.g., the mixed region) contain the organic compound (C) that does not boil at 100° C. under 1 atm. The mixed region can be formed by manufacturing the electrolytic capacitor (E) using the manufacturing method (M). In this case, the organic compound (C) present in the mixed region is contained in the liquid(S) used in the liquid application step.
The electrolytic capacitor (E) includes the mixed region, and therefore, the ESR can be reduced. Also, the effects described above can be obtained by manufacturing the electrolytic capacitor (E) using the manufacturing method (M).
The following describes an example of the configuration and constituent elements of the electrolytic capacitor (E) manufactured using the manufacturing method (M). An example electrolytic capacitor described below includes a capacitor element, an exterior body, an anode lead terminal, and a cathode lead terminal. Note that the configuration and constituent elements of the electrolytic capacitor (E) are not limited to those in the following example.
The electrolytic capacitor (E) includes a stacked body and a liquid component (L) with which the stacked body is impregnated. The stacked body includes a conductive polymer layer. The stacked body functions as a capacitor element. The stacked body includes an anode foil having a dielectric layer formed on a surface thereof, a cathode foil, and a separator. The electrolytic capacitor (E) usually includes an exterior body in which the stacked body is enclosed.
Examples of the anode foil include metal foils containing at least one valve metal such as titanium, tantalum, aluminum, and niobium, and the anode foil may be a metal foil of a valve metal (for example, an aluminum foil). The anode foil may contain a valve metal in the form of an alloy containing the valve metal, a compound containing the valve metal, or the like. The thickness of the anode foil may be 15 μm or more and 300 μm or less. A 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 chemical conversion treatment. In this case, the dielectric layer may contain an oxide of a valve metal (for example, an aluminum oxide). The dielectric layer only needs to function as a dielectric and may be formed of any dielectric other than an oxide of a valve metal.
The electrolytic capacitor may have a configuration in which the conductive polymer layer is not formed on edge surfaces of the anode foil. On the other hand, it is desirable that the dielectric layer is formed on the edge surfaces of the anode foil.
The cathode foil is not particularly limited as long as it functions as a cathode. Examples of the cathode foil include a metal foil (for example, an aluminum foil). The type of the metal is not particularly limited, and the metal may be a valve metal or an alloy containing a valve metal. The thickness of the cathode foil may be 15 μm or more and 300 μm or less. A surface of the cathode foil may be roughened or subjected to chemical conversion treatment as necessary.
The cathode foil may include a conductive coating layer. When the metal foil used for the cathode foil contains a valve metal, the coating layer may contain carbon and at least one metal having a lower ionization tendency than the valve metal. This makes it easier to improve the acid resistance of the metal foil. When the metal foil contains aluminum, the coating layer may contain at least one selected from the group consisting of carbon, nickel, titanium, tantalum, and zirconium. In particular, nickel and/or titanium may be contained in the coating layer in terms of their low cost and low resistance.
The thickness of the coating layer may be 5 nm or more, or 10 nm or more, and may be 200 nm or less. The coating layer may be formed on the metal foil by performing vapor deposition or sputtering using the above metal. Alternatively, the coating layer may be formed on the metal foil by performing vapor deposition using a conductive carbon material or applying a carbon paste containing a conductive carbon material. Examples of the conductive carbon material include graphite, hard carbon, soft carbon, carbon black, and the like.
A porous sheet can be used as the separator. Examples of the porous sheet include woven fabric, nonwoven fabric, and a microporous membrane. The thickness of the separator is not particularly limited and may be within a range from 10 to 300 μm. Examples of a material for the separator include cellulose, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, vinylon, nylon, aromatic polyamide, polyimide, polyamide imide, polyetherimide, rayon, glass, and the like.
The exterior body includes a case and/or a sealing resin. There is no limitation on the case and the sealing resin, and it is possible to use a known case and a known sealing resin. The sealing resin may include a thermosetting resin. Examples of the thermosetting resin include epoxy resin, phenolic resin, silicone resin, melamine resin, urea resin, alkyd resin, polyurethane, polyimide, unsaturated polyester, and the like. The sealing resin may contain a filler, a curing agent, a polymerization initiator, and/or a catalyst, for example.
Hereinafter, an example of the present disclosure will be specifically described with reference to the drawings. The constituent elements described above can be applied to constituent elements of the following example. Also, the constituent elements of the following example can be modified based on the above description. Also, matters described below may be applied to the embodiment described above. In the following example, constituent elements that are not essential to the electrolytic capacitor according to the present disclosure may be omitted.
The electrolytic capacitor 100 includes the capacitor element 10, a bottomed case 101 in which the capacitor element 10 is housed, a sealing member 102 sealing an opening of the bottomed case 101, a base plate 103 covering the sealing member 102, lead wires 104A and 104B drawn out from the sealing member 102 and passing through the base plate 103, and lead tabs 105A and 105B connecting the lead wires and electrodes of the capacitor element 10. The vicinity of an open end of the bottomed case 101 is pressed inward through drawing, and the open end is curled so as to be swaged on the sealing member 102.
The capacitor element 10 is a wound body like that shown in
A dielectric layer (not shown) is formed on a surface of the anode foil 11. The anode foil 11 and the cathode foil 12 are wound with the separator 13 disposed therebetween. The outermost turn of the wound body is fixed with a winding end tape 14. Note that
The electrolytic capacitor only needs to include at least one capacitor element, and may include a plurality of capacitor elements. The number of capacitor elements included in the electrolytic capacitor can be determined depending on the application.
The following describes the present disclosure more specifically based on examples, but the present disclosure is not limited to the examples. In the examples, a plurality of electrolytic capacitors were produced and evaluated using the following methods.
An electrolytic capacitor (capacitor A1) was produced using the following method.
Surfaces of an aluminum foil (thickness: 100 μm) were roughened by performing etching on the aluminum foil. Dielectric layers were formed on the roughened surfaces of the aluminum foil by performing chemical conversion treatment. Thus, an anode foil having the dielectric layers on both surfaces thereof was obtained. Surfaces of an aluminum foil (thickness: 50 μm) were roughened by performing etching on the aluminum foil to obtain a cathode foil.
Nonwoven fabric (thickness: 50 μm) was prepared as a separator. The nonwoven fabric was constituted of 50% by mass of synthetic fibers (25% by mass of polyester fiber and 25% by mass of aramid fiber) and 50% by mass of cellulose, and contained polyacrylamide as a paper strength enhancing agent. The density of the nonwoven fabric was 0.35 g/cm3.
A dispersion liquid (commercially available product) in which particles of polyethylenedioxythiophene (PEDOT) doped with polystyrene sulfonic acid (PSS) were dispersed in water was prepared, and diluted with water as necessary. The content of the conductive polymer component (PEDOT/PSS) was set to 2.0% by mass.
The application liquid was applied to a surface of the anode foil (a surface of a dielectric layer) with use of a gravure coater. Thereafter, drying was performed to form a conductive polymer layer on the surface of the anode foil (the surface of the dielectric layer). The drying was performed by heating the anode foil, to which the application liquid had been applied, at 125° C. for 5 minutes. Next, a conductive polymer layer was formed on another surface of the anode foil (a surface of another dielectric layer) using the same method.
Conductive polymer layers were formed on both surfaces of the cathode foil using the same method as that used to form the conductive polymer layers on both surfaces of the anode foil. Also, conductive polymer layers were formed on the separator by applying the application liquid to the separator and then performing drying using the same method as that used to form the conductive polymer layers on both surfaces of the anode foil.
The anode foil, the cathode foil, and the separator were each cut into a predetermined size. An anode lead tab and a cathode lead tab were connected to the anode foil and the cathode foil. Next, the anode foil and the cathode foil were wound with the separator disposed therebetween. An anode lead wire and a cathode lead wire were respectively connected to end portions of the lead tabs protruding from the wound body. An end portion of an outer surface of the wound body was fixed with a winding end tape to obtain a capacitor element.
First, a liquid(S) was prepared by mixing water and ethylene glycol (organic compound (C)). The capacitor element (stacked body) was impregnated with the obtained liquid(S).
A portion of the liquid(S) was removed by heating the capacitor element after 1 minute had elapsed from when the capacitor element was impregnated with the liquid(S). The capacitor element was heated at 125° C. for 30 minutes. In this removal step, a portion of the liquid(S) was removed such that the organic compound (C) remained in the conductive polymer layers. A mass ratio between the organic compound (C) and the conductive polymer component in the conductive polymer layers after the removal step was determined using a method described below.
(g) Impregnation with Liquid Component
An electrolyte solution (liquid component) was prepared by dissolving o-phthalic acid and triethylamine (base component) at a total concentration of 25% by mass in ethylene glycol (solvent). The capacitor element was immersed in the electrolyte solution for 5 minutes in a reduced pressure atmosphere (40 kPa). Thus, the capacitor element (stacked body) was impregnated with the electrolyte solution.
An electrolytic capacitor like that shown in
Electrolytic capacitors (capacitors A2 to A24) were produced using the same method as that used to produce the capacitor A1, except that the type and concentration of the organic compound (C) used in the liquid(S) were changed. The type of the organic compound (C) was changed as shown in Table 1. Also, in the production of the capacitor A4, heating was performed at 135° C. for 30 minutes in the removal step. The produced capacitors were evaluated using the following methods. A capacitor C1 was produced using the same method as that used to produce the capacitor A1, except that the liquid application step and the removal step were not performed.
The conductive polymer layers, the wound bodies, and the capacitors described above were evaluated using the following methods.
A ratio Wc/Wp between a mass Wc of the organic compound (C) remaining in the formed conductive polymer layers and a mass Wp of the conductive polymer component contained in the conductive polymer layers was determined.
The mass Wp can be calculated from a concentration of the conductive polymer component in the dispersion liquid (application liquid) containing the conductive polymer component, and a mass of the dispersion liquid used to form the conductive polymer layers.
The mass Wc was calculated as follows. First, a mass W0 (initial value) of the capacitor element was measured after the conductive polymer layers were formed and before the liquid application step was performed. Next, a mass W1 (after treatment) of the capacitor element was measured after the liquid application step and the removal step were performed. Then, the mass Wc can be calculated by obtaining a mass difference (W1-W0) between the mass W1 after treatment and the initial mass W0. It is thought that, in this example, almost all water contained in the liquid(S) with which the capacitor element was impregnated was removed in the removal step. Accordingly, the mass difference (W1-W0) was taken to be the mass Wc. Note that it is also possible to determine a mass Ww of water remaining in the conductive polymer layers using Karl Fischer titration, and take (W1-W0-Ww) to be Wc.
The adhesion between the anode foil and the separator was evaluated using a peeling test machine.
The equivalent series resistance (ESR) and a leakage current (LC) were measured for each of the initial electrolytic capacitors after the aging described above. Furthermore, the electrolytic capacitors were left to stand in an atmosphere at 145° C. for 1000 hours, and then the ESR and the leakage current were measured. The leakage current was measured by applying a rated voltage and measuring a current value after 120 seconds. The measurement was performed at 20° C.
Compositions of the application liquids used in the production of the electrolytic capacitors and evaluation results are shown in Tables 1 and 2. Note that “#200”, “#300”, “#400”, and “#2000” in Table 2 indicate that the weight average molecular weight was about 200, about 300, about 400, and about 2000, respectively.
The capacitors A1 to A24 were produced using the manufacturing method including the liquid application step and the removal step, and the organic compound (C) remained in the conductive polymer layers. As shown in Tables 1 and 2, the ESR and the leakage current of the capacitors A1 to A24 were lower than the ESR and the leakage current of the capacitor C1, which is a comparative example. In particular, the ESR and the leakage current of the capacitors A1 to A24 after the capacitors were left to stand in a high-temperature atmosphere were significantly lower than the ESR and the leakage current of the capacitor C1.
The present disclosure can be applied to electrolytic capacitors.
Although the present invention has been described with respect to a presently preferred embodiment, such disclosure should not be interpreted as limiting the present invention. Various modifications and alterations will undoubtedly become apparent to those skilled in the art to which the present invention pertains upon reading the above disclosure. Therefore, the appended claims should be interpreted to include all modifications and alterations without departing from the true spirit and scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-012069 | Jan 2022 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2023/002689 | 1/27/2023 | WO |
