Method for manufacturing electrolytic capacitor

Abstract

The disclosed manufacturing method includes: process (i), preparing an anode base material (200) with an exposed end face metal foil; process (ii), connecting a plurality of anode lead members (210) to the anode base material (200), and forming a second dielectric layer on the aforementioned end face (200s); process (iii), cutting the anode base material (200) to a specified length, thereby forming a plurality of anode bodies (21) connected with the anode lead members (210); process (iv), stacking the anode body (21), a cathode body, and a spacer, thereby forming a stack; and process (v), impregnating the stack with a conductive polymer and an electrolyte. Process (ii) includes: process (ii-a), connecting a plurality of anode lead members (210) to the anode base material (200); and process (ii-b), performing formation treatment by immersing the anode base material (200) in a formation solution (301), thereby forming a second dielectric layer on the end face (200s).

Description

Technical Field

[0001] This invention relates to a method for manufacturing an electrolytic capacitor. Background Technology

[0002] An electrolytic capacitor comprises an anode and a dielectric layer formed on the surface of the anode. Generally, the dielectric layer is formed by anodizing (forming) the surface of the anode.

[0003] Various methods of anodizing have been proposed in the past. Patent Document 1 (Japanese Patent Application Publication No. 2017-168740) discloses "a method for manufacturing an electrolytic capacitor, characterized in that it includes: a first step of winding an anode foil having a first dielectric film formed thereon and a cathode foil facing the anode foil to form a winding element; and a second step of applying a voltage from a DC power source between the anode foil and the reservoir while immersing the winding element in a solution stored in a conductive reservoir, thereby forming a second dielectric film on the anode foil, wherein in the second step, the potential of the cathode foil is reduced by discharging from the cathode foil."

[0004] Furthermore, Patent Document 2 (Japanese Patent Application Publication No. 04-312912) and Patent Document 3 (Japanese Patent Application Publication No. 04-312913) disclose methods for manufacturing electrode terminals for electrolytic capacitors. For example, Patent Document 2 discloses "a method for manufacturing electrode terminals for electrolytic capacitors, characterized in that an aluminum connector comprising a flat portion that has undergone chemical formation and round rod portions located on both sides thereof is formed; after a lead is attached to the round rod portion, the flat portion is riveted (Japanese: カシメ) at predetermined intervals to hold an aluminum foil in a strip shape; and then each aluminum connector is wound around a spool with the aluminum foil in between and subjected to a re-chemical formation process."

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2017-168740

[0008] Patent Document 2: Japanese Patent Application Publication No. 04-312912

[0009] Patent Document 3: Japanese Patent Application Publication No. 04-312913 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] Electrolytic capacitors using conductive polymers and electrolytes as electrolytes (hybrid electrolytic capacitors) are used in various fields due to their high performance. Hybrid electrolytic capacitors are used in applications requiring high rated voltages, among others. Therefore, it is sometimes not preferable to directly use the dielectric layer formation method used in general aluminum electrolytic capacitors or solid electrolyte capacitors as the dielectric layer formation method for hybrid electrolytic capacitors. Under these circumstances, one of the objects of the present invention is to provide a method suitable for manufacturing hybrid electrolytic capacitors.

[0012] Methods for solving problems

[0013] One aspect of the present invention relates to a method for manufacturing an electrolytic capacitor. The method comprises an electrolytic capacitor comprising an anode body, spacers, and a cathode body having a predetermined length and a predetermined width and having a dielectric layer formed on their surfaces. The method includes: step (i), preparing an anode substrate, wherein the anode substrate is an anode substrate comprising a strip of metal foil having a length at least twice the predetermined length and a predetermined width, and a first dielectric layer formed on two main surfaces of the metal foil, the metal foil being exposed at an end face of the anode substrate; step (ii), connecting a plurality of anode lead members to the anode substrate and forming a second dielectric layer at the end face; and step (iii), processing the anode substrate after step (ii). The substrate is cut to the specified length to form a plurality of anode bodies connected to the anode lead members; step (iv) involves stacking the anode body, the cathode body, and the spacer in such a way that the spacer formed in step (iii) is disposed between them to form the laminate; and step (v) involves impregnating the laminate with a conductive polymer and an electrolyte, wherein step (ii) includes: step (ii-a) connecting the plurality of anode lead members to the anode substrate; and step (ii-b) immersing the anode substrate in a forming solution for forming treatment, thereby forming the second dielectric layer on the end face.

[0014] Invention Effects

[0015] According to the present invention, a hybrid electrolytic capacitor can be manufactured using a manufacturing method suitable for hybrid electrolytic capacitors.

[0016] The novel features of the invention are set forth in the appended claims. For the purposes of this invention, both in terms of its structure and content, together with other objects and features of the invention, should be more fully understood by referring to the following detailed description with reference to the accompanying drawings. Attached Figure Description

[0017] Figure 1AThis is a schematic diagram illustrating one step of an example of the manufacturing method of the present invention.

[0018] Figure 1B It is a schematic representation of what follows. Figure 1A A diagram illustrating an example of a process following a process.

[0019] Figure 1C It is a schematic representation of what follows. Figure 1B A diagram illustrating an example of a process following a process.

[0020] Figure 1D It is a schematic representation of what follows. Figure 1C A diagram illustrating an example of a process following a process.

[0021] Figure 1E It is a schematic representation of what follows. Figure 1D A diagram illustrating an example of a process following a process.

[0022] Figure 2 This is a cross-sectional view schematically illustrating an example of an electrolytic capacitor manufactured using the manufacturing method of the present invention. Detailed Implementation

[0023] Hereinafter, embodiments of the manufacturing method of the present invention will be described by way of example; however, the present invention is not limited to the examples described below. In the following description, specific numerical values ​​and materials are sometimes shown; however, other numerical values ​​and materials may be applied as long as the effects of the present invention can be obtained. In this specification, the phrase "numerical value A to numerical value B" includes both numerical value A and numerical value B, and can be read as "numerical value A or higher and numerical value B or lower". In the following description, when lower and upper limits are shown for specific physical properties, conditions, etc., any of the shown lower limits and any of the shown upper limits may be arbitrarily combined as long as the lower limit does not exceed the upper limit.

[0024] (Manufacturing method of electrolytic capacitors)

[0025] The manufacturing method of this embodiment is a method for manufacturing an electrolytic capacitor comprising an anode body, a spacer, and a cathode body, each having a predetermined length L2 and a predetermined width W2 and having a dielectric layer formed on their surface. The spacer is disposed between the anode body and the cathode body. The laminate may also be composed of alternating sheet-like anode bodies and sheet-like cathode bodies, and a spacer disposed between the anode body and the cathode body. Alternatively, the laminate may be a wound body formed by winding a strip-shaped anode body, a strip-shaped cathode body, and a strip-shaped spacer such that a spacer is disposed between the anode body and the cathode body. In the wound body, the anode body, the cathode body, and the spacer are stacked radially along the wound body.

[0026] The specified width W2 can be 10mm or more, 15mm or more, or 20mm or more. The width W2 can be less than 50mm or less, or less than 40mm. For example, the width W2 can be in the range of 10mm to 50mm, 15mm to 50mm, or 20mm to 50mm. Within any of these ranges, the upper limit can be set to 40mm.

[0027] The specified length L2 is greater than the width W2. Length L2 can be 100mm or more, 200mm or more, or 300mm or more. Length L2 can also be less than 1000mm or less than 800mm. For example, length L2 can be in the range of 100–1000mm, 200–1000mm, or 300–1000mm. Within any of these ranges, the upper limit can be set to 800mm. Length L2 can be more than twice the width W2 or less than 100 times it.

[0028] The thickness of the anode body is not particularly limited and can be in the range of 80μm to 200μm (e.g., 100μm to 130μm).

[0029] The manufacturing method of this embodiment includes the following steps (i) to (v) in sequence.

[0030] (Process (i))

[0031] Step (i) is the process of preparing the anode substrate, which is an anode substrate comprising a strip of metal foil having a length L1 that is at least twice the length L2 (the length of the anode body of the electrolytic capacitor) and a width W2 (the width of the anode body of the electrolytic capacitor), and a first dielectric layer formed on the two main surfaces of the metal foil, with the metal foil exposed at the end face (or cut surface from another viewpoint). The metal foil is a metal foil (e.g., aluminum foil) that can be used as the anode body of an electrolytic capacitor. Typically, the two main surfaces of the anode body (metal foil) are roughened (or porous from another viewpoint). The length L1 can be more than twice, more than ten times, or more than 100 times the length L2, and can be less than 10,000 times, less than 5,000 times, or less than 1,000 times. The length L1 can be in the range of 2 to 10,000 times the length L2 (e.g., in the range of 100 to 5,000 times). By increasing the value of L1 / L2, multiple anode bodies can be manufactured at once. On the other hand, by setting the value of L1 / L2 to a moderate value or below, the operation of the anode substrate becomes easier.

[0032] Commercially available materials can be used as the anode substrate. Alternatively, the anode substrate can be formed using the following method. First, after roughening the surface of a sheet metal foil, a first dielectric layer is formed on the roughened surface (step (ia)). The length L0 of the sheet metal foil is at least one time the length L1 (e.g., in the range of 1 to 10 times), and the width W0 of the sheet metal foil is at least two times the width W2 (e.g., in the range of 5 to 500 times). Roughening can be performed using known methods (e.g., etching). Using step (ia), the first dielectric layer is formed on the two main surfaces of the sheet metal foil (more specifically, the roughened main surfaces). The first dielectric layer can be formed using a chemical formation process. The first dielectric layer formed using the chemical formation process is an oxide of the metal constituting the metal foil (the same applies to the chemical formation process described later). For example, in the case where the sheet metal foil is aluminum foil, an aluminum oxide layer is formed using a chemical formation process. The methods and conditions for roughening and chemical formation in step (i) are not particularly limited, and known methods and conditions can be used.

[0033] The formation process in step (ia) is not limited, and any known formation process used in forming the dielectric layer on the surface of the anode body of an electrolytic capacitor can be used. The thickness of the first dielectric layer can be determined based on the required performance of the electrolytic capacitor. When manufacturing electrolytic capacitors with high rated voltage, the thickness of the first dielectric layer is increased. For example, when manufacturing an electrolytic capacitor with a rated voltage of 100V, the thickness of the first dielectric layer can be set to 200nm or more.

[0034] Then, the sheet metal foil that has undergone process (ia) is cut to the size of the anode substrate (process (ib)). For example, the sheet metal foil wound into a roll can be cut into multiple rolls, such that the width of one roll is W2. At this time, no dielectric layer is formed on the cut surface (end face), but the metal foil is exposed on the cut surface (end face).

[0035] (Process (ii))

[0036] Step (ii) is the process of connecting multiple anode lead components to the anode substrate and forming a second dielectric layer on the aforementioned end face. Step (ii) includes: step (ii-a), connecting multiple anode lead components to the anode substrate; and step (ii-b), immersing the anode substrate in a forming solution for a forming treatment, thereby forming the second dielectric layer on the aforementioned end face. It should be noted that since the second dielectric layer is formed by the forming treatment (anodic oxidation) of the anode substrate, it is usually made of the same material as the first dielectric layer. For example, if the anode substrate contains aluminum, the second dielectric layer is an aluminum oxide layer.

[0037] In step (ii), step (ii-b) is usually performed after step (ii-a). However, step (ii-a) can also be performed after step (ii-b).

[0038] There are no particular limitations on the anode lead member, and known anode lead members can be used. For example, an anode lead member comprising a plate-shaped portion fixed and connected to the anode substrate, a rod-shaped portion connected to the plate-shaped portion, and a lead portion connected to the rod-shaped portion can be used. The anode lead member can be formed of metal. The rod-shaped portion corresponds to the protrusion described later. The plate-shaped portion comprises metals such as aluminum. The rod-shaped portion can be a rod-shaped piece of iron whose surface is covered with a metal other than iron (e.g., copper and / or tin). The metal covering the surface can be formed by plating, or by methods other than plating. The lead portion can be made of wire-shaped metal. The end of the anode lead member (e.g., the plate-shaped portion described above) is fixed to the anode substrate by welding, riveting, etc., and is electrically connected to the anode substrate.

[0039] Multiple anode lead members are arranged at predetermined intervals. Typically, this interval is set to be the same as the length L2 (the length of the anode body of the electrolytic capacitor). Thus, when the anode substrate is cut in step (iii), one anode lead member is arranged for each anode body.

[0040] In step (ii-b), the formation process is performed while the anode substrate is immersed in the formation solution. The formation solution can be an aqueous solution of acid salts such as phosphates, borates, or adipates, or other aqueous solutions such as phosphoric acid.

[0041] In conventional wound electrolytic capacitors, after fabricating a wound body consisting of an anode foil, a cathode foil, and spacers with dielectric layers formed on their surfaces, a formation process is performed, thereby forming a dielectric layer on the end face of the anode foil (the portion without a dielectric layer). In this case, formation liquid tends to remain inside the wound body including the spacers, potentially causing adverse effects due to the composition of the formation liquid. This is especially true when the width W2 is large, making it easier for formation liquid to remain inside the wound body. Therefore, conventional methods have limited the use of high-concentration formation liquids. However, in the method of the present invention, the end face of the anode body is formed before the wound body is formed. Therefore, after the formation process, the formation liquid adhering to the surface of the anode body can be easily removed by cleaning or the like. Thus, the method of the present invention allows the use of high-concentration formation liquids (in other words, formation liquids with high conductivity).

[0042] The conductivity of the forming solution can be 1 mS / cm or higher, or 0.1 mS / cm or higher. By making the conductivity of the forming solution 0.1 mS / cm or higher, the formation rate of the second dielectric layer can be increased. In the case of manufacturing electrolytic capacitors with high rated voltage, it is necessary to thicken the second dielectric layer in the same way as the first dielectric layer. Therefore, it is particularly important to use a high-concentration forming solution (a forming solution with high conductivity) to increase the formation rate of the second dielectric layer. There is no particular upper limit to the conductivity of the forming solution, but it can be 100 mS / cm or lower.

[0043] The thickness of the second dielectric layer formed by the formation process in step (ii-b) can be 200 nm or more, or 150 nm or more. In step (ii-b), by forming a second dielectric layer with a thickness of 150 nm or more, a high-voltage electrolytic capacitor can be manufactured. There is no particular upper limit to the thickness of the second dielectric layer; however, it can be, for example, 800 nm or less (the same applies to the first dielectric layer).

[0044] The applied voltage during the formation process can be 300V or higher, or 200V or higher. In step (ii-b), by forming the anode substrate with a formation voltage of 200V or higher, the formation rate of the second dielectric layer can be increased. There is no particular upper limit to the applied voltage; it can be set to 600V or lower.

[0045] In conventional manufacturing methods, the end face of the anode body is formed while it is in a wound state consisting of an anode body, a cathode body, and spacers. In this case, if the formation process is performed with a high applied voltage (e.g., 200V or higher), problems such as discharge may occur between the anode lead to which the high voltage is applied and the cathode lead member present nearby. However, this problem can be avoided by the method according to the present invention.

[0046] In step (ii-b), it is preferable to perform the formation process while a portion of the anode lead member protruding from the anode substrate is also immersed in the formation solution. This allows a formation film (dielectric layer) to be formed on the surface of that portion as well.

[0047] The anode lead member may include a connecting portion made of metal and connected to the anode substrate, and a lead portion connected to the connecting portion. The connecting portion may include a plate-like portion that contacts the anode substrate and a protrusion that does not contact the anode substrate but protrudes from it. In a preferred embodiment, the length of the protrusion is 2 mm or more, and in step (ii-b), the length of the portion of the protrusion immersed in the forming solution is set to 1 mm or less. This can suppress corrosion breakage of the lead member and insufficient formation of the forming film (dielectric layer) caused by the forming solution reaching the junction of the protrusion and the lead portion. There is no particular upper limit to the length of the protrusion, but it may be, for example, 5 mm or less. The length of the portion of the protrusion immersed in the forming solution may be, for example, 0 mm or more, or the protrusion may not be immersed in the forming solution. The protrusion may be, for example, the rod-like portion described above.

[0048] In step (ii-b), the formation process can be performed either when the anode substrate is flat or when it is rolled up. For example, the formation process can be performed when the anode substrate is rolled into a roll. In this case, if a certain gap is provided between the anode substrates that overlap radially along the roll, the forming liquid can be fully distributed throughout the roll. Therefore, unlike the case where the formation process is performed when the capacitor element is wound, a dielectric layer with less fluctuation due to different locations can be formed. In step (ii-b), by performing the formation process when the anode substrate is wound, the formation process can be performed efficiently. It should be noted that when the width W2 is large, if the formation process is performed when the capacitor element is wound, the forming liquid will not be fully distributed throughout the entire structure, and the thickness fluctuation of the dielectric layer is likely to increase. Therefore, the method of the present invention is particularly effective when the width W2 is large (for example, when W2 is 10 mm or more).

[0049] (Process (iii))

[0050] Step (iii) is a process of forming multiple anode bodies with connected anode lead members by cutting the anode substrate that has undergone step (ii) to a specified length L2. The method of cutting the anode substrate is not limited; any known method may be used. Each formed anode body is connected to at least one (usually one) anode lead member.

[0051] The metal foil is exposed at the cut surface formed in step (iii). However, since the width W2 is shorter than the length L2, the impact of the exposed metal foil in step (iii) is small. It should be noted that after the laminate is formed in step (iv), a formation process can be performed as an auxiliary step. In this case, the formation process can be performed under milder conditions than the formation process in steps (ii-b) (lower applied voltage, formation solution with lower conductivity, etc.).

[0052] (Process (iv))

[0053] Step (iv) is a process of forming a laminate by stacking the anode body, cathode body, and spacers in a manner where spacers are arranged between the anode body and cathode body formed in step (iii). For example, a strip-shaped anode body, a strip-shaped cathode body, and a strip-shaped spacer can be wound together with spacers arranged between the anode body and cathode body. This forms a wound body (laminated body). Alternatively, multiple anode bodies, multiple cathode bodies, and multiple spacers can be stacked with spacers arranged between the anode body and cathode body. The multiple anode bodies and multiple cathode bodies are arranged alternately. Step (iv) can be carried out using known methods.

[0054] The spacer can be a sheet material that can be impregnated with an electrolyte, for example, a sheet material that is both insulating and capable of being impregnated with an electrolyte. The spacer can be woven fabric, nonwoven fabric, or a porous membrane. Examples of spacer materials include cellulose, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, vinylon, nylon, aromatic polyamide, polyimide, polyamide-imide, polyether-imide, rayon, and glass.

[0055] When manufacturing electrolytic capacitors with high rated voltage, the areal density of the spacer is preferably 20 g / m². 2 above.

[0056] (Cathode)

[0057] The cathode can be made of metal foil (e.g., aluminum foil) that can be used as the cathode of an electrolytic capacitor. The surface of the metal foil can be covered with a layer containing carbon, nickel, titanium, etc.

[0058] The thickness of the cathode is not particularly limited and can be in the range of 20μm to 100μm (e.g., 30μm to 60μm). The size and shape of the cathode are roughly the same as those of the anode.

[0059] (Process(v))

[0060] Step (v) is the process of impregnating the laminate with a conductive polymer and an electrolyte. The method of carrying out step (v) is not particularly limited and can be performed using known methods. In a preferred embodiment, the conductive polymer is first impregnated into the laminate, and then the electrolyte is impregnated into the laminate.

[0061] The conductive polymer can also be impregnated into the laminate by immersing it in a dispersion containing the conductive polymer. Alternatively, the conductive polymer can be disposed on the dielectric layer of the anode by polymerizing the raw material monomers on the dielectric layer. These operations can be carried out using known methods. The electrolyte can be impregnated into the laminate by immersing it in an electrolyte. By operating as described above, a laminate (capacitor element) is obtained in which a spacer and an electrolyte are disposed between the dielectric layer of the anode and the cathode.

[0062] Examples of conductive polymers include polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, and their derivatives. These conductive polymers can be used alone or in combination. Furthermore, conductive polymers can also be copolymers of two or more monomers. A preferred example of a conductive polymer is poly(3,4-ethylenedioxythiophene) (PEDOT).

[0063] Dopants can be added to conductive polymers. From the viewpoint of suppressing dedoping from conductive polymers, polymeric dopants are preferred. Examples of polymeric dopants include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polyacrylic acid sulfonic acid, polymethacrylic acid sulfonic acid, poly(2-acrylamido-2-methylpropanesulfonic acid), polyisoprene sulfonic acid, and polyacrylic acid. They can be used alone or in combination of two or more. A preferred example of a dopant is polystyrene sulfonic acid (PSS).

[0064] The electrolyte can be any known electrolyte used in electrolytic capacitors. The electrolyte may contain a non-aqueous solvent and an alkaline and / or acidic component dissolved in the non-aqueous solvent. Examples of non-aqueous solvents include polyols 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, carbonates such as propylene carbonate, ethers such as 1,4-dioxane, ketones such as methyl ethyl ketone, and formaldehyde. Alternatively, the non-aqueous solvent may also be polyalkylene glycol, polyalkylene glycol derivatives, etc. The non-aqueous solvent of the electrolyte may consist of one type of non-aqueous solvent or multiple types of non-aqueous solvents.

[0065] Examples of acid components include maleic acid, phthalic acid, benzoic acid, pyromellitic acid, and isophthalic acid. Inorganic acids such as phosphoric acid, phosphorous acid, hypophosphite, boric acid, fluoroboric acid, tetrafluoroboric acid, and hexafluorophosphoric acid can also be used as acid components. Alternatively, organic acids such as alkyl sulfonic acids like methanesulfonic acid can be used as acid components. Alternatively, complex compounds of organic and inorganic acids can also be used as acid components.

[0066] The base component can be a compound with an alkyl-substituted amidine group, such as imidazole compounds, benzimidazole compounds, alicyclic amidine compounds (pyrimidine compounds, imidazoline compounds), etc. Alternatively, a quaternary salt of a compound with an alkyl-substituted amidine group can be used as the base component. A tertiary amine can also be used as the base component. The solute dissolved in the non-aqueous solvent can be one or more types.

[0067] Following step (v), an electrolytic capacitor is manufactured using the laminate (capacitor element) that has undergone step (v). For example, the capacitor element can be housed in a casing and the casing sealed. These methods are not limited and can be implemented using known materials and methods. By operating as described above, a hybrid type of electrolytic capacitor can be manufactured. It should be noted that at least a portion of the electrolyte can be injected into the casing after the laminate is housed in it.

[0068] When using only an electrolyte as the electrolyte, a dielectric layer of a certain degree can be formed on the exposed portion (e.g., end face) of the metal foil even without formation treatment. Therefore, in this case, formation treatment of the end face is not so important. On the other hand, in hybrid electrolytic capacitors, due to the small amount of electrolyte, the formation of the dielectric layer by the electrolyte may be insufficient. Therefore, in hybrid electrolytic capacitors, it becomes important to form a dielectric layer by forming the metal foil exposed at the end face. In addition, in hybrid electrolytic capacitors, high rated voltages are sometimes required due to their characteristics. To achieve high rated voltages, the dielectric layer at the end face needs to be thickened. For these reasons, the manufacturing method of the present invention is particularly effective in manufacturing hybrid electrolytic capacitors.

[0069] Hereinafter, examples of the manufacturing method of the present invention will be specifically described with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments. The manufacturing method of one example described below can be modified based on the above description. In addition, the matters described below can be applied to the above embodiments. It should be noted that the following figures are schematic diagrams, and the scale (e.g., aspect ratio) of the illustrated components is different from the scale of the actual components.

[0070] (Implementation Method 1)

[0071] In Embodiment 1, an example of the manufacturing method of the present invention will be described. First, as... Figure 1A As shown, the anode substrate 200 described above is prepared (step (i)). The width of the anode substrate 200 is the width W2 described above, and the length is the length L1 described above. The two main surfaces 200a of the anode substrate 200 are roughened, and a first dielectric layer (not shown) is formed on their surfaces. At the end face (cut surface) 200s of the anode substrate 200, the metal foil constituting the anode substrate 200 is exposed.

[0072] Then, as Figure 1B As shown, multiple anode lead members 210 are connected to the anode substrate 200 (step (ii-a)). Each anode lead member 210 includes a plate-shaped portion 211, a rod-shaped portion (protrusion) 212 connected to the plate-shaped portion 211, and a lead portion 213 connected to the rod-shaped portion 212. The plate-shaped portion 211 is fixed to the anode substrate 200, thereby electrically connecting the anode lead member 210 to the metal foil constituting the anode substrate 200. The rod-shaped portion 212 protrudes from the anode substrate 200. Multiple anode lead members 210 are fixed to the anode substrate 200 at intervals of length L2. It should be noted that although... Figure 2 Two anode lead components 210 are shown in the figure, however, more anode lead components 210 are connected to the anode substrate 200.

[0073] Then, as Figure 1C As shown, the anode substrate 200 is immersed in the forming solution 301 for forming treatment. Specifically, a DC voltage is applied between the anode substrate 200 and the counter electrode. Figure 1C The diagram illustrates an example where a container 302 containing the formation solution 301 is made conductive and used as a counter electrode. Alternatively, a counter electrode can be placed separately within the formation solution 301 outside the container 302 for formation processing. Using this formation process, a second dielectric layer (not shown) is formed on the end face 200s of the anode substrate 200 (step (ii-b)). Figure 1C As shown, the formation process is preferably performed while a portion of the rod-shaped portion 212 is immersed in the formation solution 301.

[0074] Figure 1C The diagram illustrates an example of forming anode material 200 without winding it. However, as described above, forming anode material 200 can also be formed while wound into a roll. Since multiple plate-shaped portions 211 are fixed to the anode material 200, even when the anode material 200 is wound into a roll, gaps are formed between the anode materials 200 stacked radially along the roll. Therefore, even when the anode material 200 is wound into a roll, the forming solution sufficiently penetrates into the roll.

[0075] Then, as Figure 1D As shown, the anode substrate 200, on which the second dielectric layer (not shown) is formed, is cut at intervals of a predetermined length L2, thereby forming a plurality of anode bodies 21 connected to anode lead members 210 (step (iii)).

[0076] Then, as Figure 1EAs shown, the anode body 21, cathode body 22, and spacer 23 are stacked (wound) with spacer 23 arranged between the formed anode body 21 and cathode body 22, thereby forming a stacked body (wound body) 20 (step (iv)). The outermost periphery of the wound body is fixed by a winding fixing tape 24. Figure 1E This shows the partially unfolded state before the outermost circumference of the wound body is fixed. A cathode lead member 220 is connected to the cathode body 22. The cathode lead member 220, like the anode lead member 210, includes a plate-shaped portion (not shown), a rod-shaped portion (protrusion) 222, and a lead portion 223.

[0077] Then, using the method described above, the laminate 20 is impregnated with a conductive polymer and an electrolyte (step (v)). Operated as described, a capacitor element 10 is formed. The formed capacitor element 10 is housed in a housing 11, thereby obtaining… Figure 2 The electrolytic capacitor 100 shown is shown.

[0078] Figure 2 The electrolytic capacitor 100 shown includes a capacitor element 10, a bottomed cylindrical housing 11 housing the capacitor element 10, a sealing member 12 sealing the opening of the housing 11, and a base plate 13 covering the sealing member 12. The capacitor element 10 is housed in the housing 11. The opening end of the housing 11 is necked inward, and the opening end of the housing 11 is rolled up in a manner that rivets the sealing member 12.

[0079] Industrial availability

[0080] This invention can be used in the manufacturing method of electrolytic capacitors.

[0081] While the invention has been described with respect to preferred embodiments, this disclosure should not be interpreted as restrictive. Various modifications and alterations will be readily apparent to those skilled in the art upon reading the foregoing disclosure. Therefore, the scope of the appended claims should be interpreted as encompassing all modifications and alterations without departing from the true spirit and scope of the invention.

[0082] Explanation of reference numerals in the attached figures

[0083] 10 Capacitor element, 11 Housing, 12 Sealing component, 20 Laminated body, 21 Anode body, 22 Cathode body, 23 Spacer, 100 Electrolytic capacitor, 200 Anode substrate, 200a Main surface, 200s End face, 210 Anode lead component, 211 Plate-shaped part, 212 Rod-shaped part, 213 Lead part, 220 Cathode lead component, 223 Lead part, 301 Forming solution.

Claims

1. A method for manufacturing an electrolytic capacitor, comprising a laminate of an anode body, a spacer, and a cathode body having a predetermined length and a predetermined width and having a dielectric layer formed on their surfaces. The manufacturing method includes: Step (i) is to prepare an anode substrate, wherein the anode substrate comprises a strip of metal foil having a length of more than twice the specified length and a specified width, and a first dielectric layer formed on two main surfaces of the metal foil, wherein the metal foil is exposed at the end face of the anode substrate; Step (ii) involves connecting a plurality of anode lead components to the anode substrate and forming a second dielectric layer on the end face; Step (iii) involves cutting the anode substrate that has undergone step (ii) to the specified length, thereby forming a plurality of anode bodies connected to the anode lead members; Step (iv) involves stacking the anode body, the cathode body, and the spacer in such a manner that the spacer is disposed between the anode body and the cathode body formed in step (iii), thereby forming the stacked body; as well as Step (v) involves impregnating the laminate with a conductive polymer and an electrolyte. The process (ii) includes: Step (ii-a): Connecting the plurality of anode lead components to the anode substrate; as well as In step (ii-b), the anode substrate is immersed in a forming solution to perform a forming treatment, thereby forming the second dielectric layer on the end face.

2. The manufacturing method according to claim 1, wherein, In the process (ii-b), the second dielectric layer with a thickness of 150 nm or more is formed.

3. The manufacturing method according to claim 1 or 2, wherein, In step (ii-b), the anode substrate is subjected to a formation treatment at a formation voltage of 200V or higher.

4. The manufacturing method according to any one of claims 1 to 3, wherein, In step (ii), step (ii-b) is performed after step (ii-a).

5. The manufacturing method according to any one of claims 1 to 4, wherein, In step (ii-b), a formation process is performed while the anode substrate is wound up.

6. The manufacturing method according to any one of claims 1 to 5, wherein, The areal density of the spacer is 20 g / m³. 2 above.

7. The manufacturing method according to any one of claims 1 to 6, wherein, The specified width is 10mm or more.

8. The manufacturing method according to any one of claims 1 to 7, wherein, The anode lead member includes a connector made of metal and connected to the anode substrate, and a lead portion connected to the connector. The connecting portion includes a plate-shaped portion that contacts the anode substrate and a protruding portion that does not contact the anode substrate but protrudes from the anode substrate. The length of the protrusion is 2mm or more. In the process (ii-b), the length of the portion of the protrusion immersed in the chemical solution is set to less than 1 mm.

9. The manufacturing method according to any one of claims 1 to 8, wherein, The conductivity of the formation liquid is above 0.1 mS / cm.

10. The manufacturing method according to any one of claims 1 to 9, wherein, The rated voltage of the electrolytic capacitor is above 100V.

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