Electrolytic capacitors, apparatus and methods for manufacturing electrolytic capacitors

Abstract

This invention relates to electrolytic capacitors, an apparatus for manufacturing electrolytic capacitors, and a method for manufacturing electrolytic capacitors. The problem to be solved by this invention is to provide a method for manufacturing an electrolytic capacitor, an electrolytic capacitor, and an apparatus for manufacturing an electrolytic capacitor in which a fiber membrane, integrally formed as a spacer with one of the electrodes, is provided, and the uniformity of the conductive polymer in the fiber membrane is improved. According to the method for manufacturing an electrolytic capacitor according to an embodiment, a raw material liquid is sprayed toward a substrate that serves as an electrode, thereby forming a fiber membrane serving as a spacer on the surface of the substrate. In the formation of the fiber membrane, the fibers are formed to be thicker at the ends of the substrate in the width direction compared to the central portion of the substrate in the width direction.

Description

Technical Field

[0001] The embodiments of the present invention relate to a method for manufacturing an electrolytic capacitor, an electrolytic capacitor, and an apparatus for manufacturing an electrolytic capacitor. Background Technology

[0002] Electrolytic capacitors are widely used as capacitors. In an electrolytic capacitor, the capacitor element is housed inside a casing. Furthermore, the capacitor element is formed, for example, by winding a coiled body, in which an anode and a cathode are stacked with spacers between them, and the stacked body of the anode, cathode, and spacers is wound to form the aforementioned coiled body. Inside the casing, the capacitor element contains an electrolyte. An electrolytic capacitor is one in which one of the pairs of electrodes (anode and cathode) is integrally formed with a spacer. In the manufacture of such an electrolytic capacitor, a raw material liquid is sprayed toward a substrate that serves as one of the pairs of electrodes using a spinning method or similar means, thereby forming a fibrous film as a spacer on the surface of the electrode that serves as the substrate.

[0003] Furthermore, in the manufacture of electrolytic capacitors, before the wound body, which will become the capacitor element, is immersed in the electrolyte, it is impregnated in a solution containing a conductive polymer, thereby impregnating the spacer with the conductive polymer. Thus, in the electrolytic capacitor, the conductive polymer is retained in the spacer. As described above, in electrolytic capacitors where the spacer is formed by a fiber membrane integral with one of a pair of electrodes, it is required to effectively prevent the distribution of conductive polymer in the fiber membrane that serves as the spacer from becoming uneven. That is, it is required to improve the uniformity of the distribution of conductive polymer in the fiber membrane. Summary of the Invention

[0004] The problem to be solved by the present invention is to provide a method for manufacturing an electrolytic capacitor, an electrolytic capacitor, and an apparatus for manufacturing an electrolytic capacitor, wherein a fiber membrane serving as a spacer is integrally formed with one of the electrodes, and the uniformity of the conductive polymer in the fiber membrane is improved.

[0005] According to the method for manufacturing an electrolytic capacitor according to the embodiment, a fiber film serving as spacers is formed on the surface of a substrate by spraying a raw material liquid toward a substrate that serves as an electrode. In the formation of the fiber film, the fibers are formed thicker at the ends of the substrate in the width direction compared to the central portion of the substrate in the width direction.

[0006] According to the above-described method for manufacturing an electrolytic capacitor, the electrolytic capacitor, and the apparatus for manufacturing an electrolytic capacitor, a fiber membrane that serves as a spacer is integrally formed with one of the electrodes, which can improve the uniformity of the conductive polymer in the fiber membrane. Attached Figure Description

[0007] Figure 1This is a schematic diagram showing an example of the electrolytic capacitor of the first embodiment.

[0008] Figure 2 This is indicated when the capacitor element is separated from the casing. Figure 1 A schematic diagram of an electrolytic capacitor.

[0009] Figure 3 This is a schematic diagram illustrating an example of a strip-shaped body in the electrolytic capacitor of the first embodiment in which the anode and the spacer are integrated.

[0010] Figure 4 This is a schematic diagram showing the manufacturing apparatus for manufacturing the strip in the first embodiment.

[0011] Figure 5 It means in Figure 4 The state in which an organic fiber membrane is formed on the surface of a substrate in the spinning section of the manufacturing apparatus, and a schematic diagram of the substrate (ribbon) showing a cross section orthogonal or approximately orthogonal to the length direction.

[0012] Figure 6 This is a cross-sectional view showing the central portion of the strip in the width direction of the electrolytic capacitor in the first embodiment.

[0013] Figure 7 This is a cross-sectional view showing the end of the strip in the width direction of the electrolytic capacitor in the first embodiment.

[0014] Figure 8 This is a schematic diagram illustrating an example of the process of immersing a capacitor element in a solution containing a conductive polymer during the manufacture of the electrolytic capacitor according to the first embodiment.

[0015] Figure 9 This is a schematic diagram showing the protrusion and concavity forming part provided in the manufacturing apparatus for manufacturing a strip in a certain modified example. Detailed Implementation

[0016] The embodiments will now be described with reference to the accompanying drawings.

[0017] (First Embodiment)

[0018] Figure 1 as well as Figure 2 This illustrates an example of the electrolytic capacitor 1 according to the first embodiment. For example... Figure 1 as well as Figure 2 As shown, the electrolytic capacitor 1 includes a housing 2 and a capacitor element 3 housed inside the housing 2. The housing 2 is formed, for example, of aluminum or an aluminum alloy. Furthermore, the capacitor element 3 is impregnated with an electrolyte inside the housing 2. Figure 2The image shows the state in which the capacitor element 3 is separated from the housing 2.

[0019] The capacitor element 3 includes an anode 5, a cathode 6, and a spacer 7. The anode 5 and cathode 6 are stacked in the capacitor element 3, with the spacer 7 separating them. The capacitor element 3 is then formed by winding the stacked body of the anode 5, cathode 6, and spacer 7. The spacer 7 is electrically insulating, and in the capacitor element 3, it electrically insulates the anode 5 from the cathode 6.

[0020] The anode 5 includes a conductive metal layer and a dielectric layer formed on the surface of the metal layer. In one example, the metal layer of the anode 5 is formed of aluminum or an aluminum alloy, and the dielectric layer is formed of an aluminum oxide film. Furthermore, the cathode 6 includes a conductive metal layer. In one example, the metal layer of the cathode 6 is formed of aluminum or an aluminum alloy. A lead terminal 8 on the anode side is connected to the metal layer of the anode 5. Furthermore, a lead terminal 9 on the cathode side is connected to the metal layer of the cathode 6. The lead terminals 8 and 9 are formed of a conductive metal or the like and extend outwards from the housing 2.

[0021] exist Figure 2 In one example, the spacer 7 is integrally formed with the anode 5, and the fibrous membrane of organic fibers formed on the surface of the anode 5 becomes the spacer 7. Figure 3 An example is shown of a strip 11 in which the anode 5 and the spacer 7 are integrally formed. For example... Figure 3 As shown, in the strip 11, that is, in each of the substrate that becomes the anode 5 and the fiber membrane that becomes the spacer 7, a length direction (the direction indicated by arrows L1 and L2), a width direction (the direction indicated by arrows W1 and W2) that intersects (orthogonally or substantially orthogonally) the length direction, and a thickness direction that intersects both the length direction and the width direction (in the direction indicated by arrows W1 and W2) are defined. Figure 3 (The direction is orthogonal or approximately orthogonal to the paper surface). The anode 5 has a pair of principal surfaces M. The pair of principal surfaces M face opposite sides relative to each other in the thickness direction. In the anode 5, both sides of the pair of principal surfaces M are covered by spacers 7.

[0022] Furthermore, edges E are formed at both ends of the anode 5 in the width direction. In the anode 5, the edges E on both sides in the width direction are also covered by a fibrous membrane called spacers 7. And in the strip 10, the spacers 7 protrude (extend) from the edges E at both ends of the anode 5 outwards in the width direction. Figures 1 to 3In one example, a capacitor element 3 is formed by winding a stack on which the cathode 6 is stacked. Furthermore, in the capacitor element 3, the length direction of the strip 11 is aligned with or substantially aligned with the circumferential direction of the wound body that forms the capacitor element 3. Also, in the capacitor element 3, the width direction of the strip 11 is aligned with or substantially aligned with the direction along the central axis of the wound body.

[0023] In another example, the spacer 7 is integrally formed with the cathode 6, and the fibrous membrane of organic fibers formed on the surface of the cathode 6 serves as the spacer 7. In this case, the strip 11, which is integral with the anode 5 and the spacer 7, is also formed as a strip integral with the cathode 6, with the fibrous membrane serving as the spacer 7. Then, the anode 5 is stacked on the strip integral with the cathode 6 and the spacer 7, and the stack of the strip and the anode 5 is wound to form the capacitor element 3.

[0024] As described above, in this embodiment, a fiber membrane serving as a spacer 7 is integrally formed with a substrate that is one of a pair of electrodes (anode 5 and cathode 6). Then, a plate member (the one different from the substrate of anode 5 and cathode 6) that will become an electrode with the opposite polarity to the substrate is laminated onto the strip 11, and the laminate of the strip 11 and the plate member is wound to form a wound body that becomes a capacitor element 3.

[0025] The manufacture of the electrolytic capacitor 1, etc., will be described below. In the manufacture of the electrolytic capacitor 1, a strip 11 is formed in which a substrate, which becomes one of a pair of electrodes, and a fiber membrane, which becomes a spacer, are integrally formed. Figure 4 A manufacturing apparatus 20 for manufacturing the strip 11 is shown. The manufacturing apparatus 20 is part of a manufacturing apparatus for manufacturing the electrolytic capacitor 1. Figure 4 As shown, the manufacturing apparatus 20 for the strip 11 includes a feeding section 21, a spinning section 22, a surface treatment section 23, a winding section 25, and a transport path P. The transport path P extends from the feeding section 21 to the winding section 25 via the spinning section 22 and the surface treatment section 23. In the manufacturing apparatus 20, a substrate 12, which is to be formed into one of a pair of electrodes, is transported along the transport path P from the feeding section 21 to the winding section 25.

[0026] In the transport path P, the transport direction in which the substrate 12 (strip 11) is transported, i.e., the direction toward the winding unit 25, is the downstream side. Furthermore, in the transport path P, the direction opposite to the transport direction, i.e., the direction toward the delivery unit 21, is the upstream side. Additionally, in the transport path P, a first direction is defined as a width direction that intersects (orthogonally or substantially orthogonally) the transport direction, and a second direction is defined as intersecting (orthogonally or substantially orthogonally) both the transport direction and the first direction. Figure 4In the paper, the first direction (width direction) of the transport path P is orthogonal or approximately orthogonal to the paper.

[0027] The delivery section 21 includes a spool 31. A substrate 12 is wound into a roller shape on the spool 31. In the delivery section 21, the spool 31 is rotated in the direction of arrow R1 by driving a drive component (not shown) such as an electric motor. As a result, the substrate 12 wound on the spool 31 is released onto the transport path P. The take-up section 25 includes a spool 32. In the take-up section 25, the spool 32 is rotated in the direction of arrow R2 by driving a drive component (not shown) such as an electric motor. As a result, the substrate 12 transported via the transport path P is taken into a roller shape by the spool 32.

[0028] In the manufacturing apparatus 20, the substrate 12 is conveyed from the delivery unit 21 to the take-up unit 25 via the conveying path P by simultaneously rotating the spool 31 in the direction of arrow R1 and the spool 32 in the direction of arrow R2. In the conveying path P, the substrate 12 (strip 11) is conveyed with its width direction aligned or substantially aligned with the first direction (width direction) of the conveying path P, and its thickness direction aligned or substantially aligned with the second direction of the conveying path P. Figure 4 In this structure, the width directions of both the substrate 12 and the strip 11 are orthogonal or substantially orthogonal to the paper surface. Furthermore, in... Figure 4 In the diagram, the directions indicated by arrows L1 and L2 are the length directions of the substrate 12 (strip 11), and the directions indicated by arrows T1 and T2 are the thickness directions of the substrate 12 (strip 11).

[0029] Alternatively, one or more guide rollers (not shown) may be provided on the transport path P to guide the substrate 12 from the feed section 21 to the winding section 25. In this case, guide rollers are arranged at least at any point in the transport path P between the feed section 21 and the spinning section 22, between the spinning section 22 and the surface treatment section 23, and between the surface treatment section 23 and the winding section 25. Furthermore, guide rollers may be arranged either within the spinning section 22 or within the surface treatment section 23.

[0030] Furthermore, the extension configuration of the transport path P from the delivery section 21 to the winding section 25 is not particularly limited. In one example, the transport path P extends horizontally, while in another example, it extends vertically. Additionally, between the delivery section 21 and the winding section 25, there may be one or more bends or reversals in the transport path P, changing the extension direction of the transport path P at these bends or reversals. In one example, a reversal portion of the transport path P is provided between the spinning section 22 and the surface treatment section 23; in another example, a reversal portion of the transport path P is provided either within the spinning section 22 or within the surface treatment section 23.

[0031] The spinning section 22 forms a fiber membrane 13, consisting of organic fibers serving as spacers, on the surface of the substrate 12 conveyed along the conveying direction P. This forms a strip 11 where the substrate 12 and the fiber membrane 13 are integrally formed. The spinning section 22 has one or more spinning heads 33. Figure 4 In one example, six spinning heads 33 are provided in the spinning section 22. Each spinning head 33 has a head body 35 and a plurality of nozzles 36 protruding from the head body 35. In each spinning head 33, a raw material liquid, such as that formed by dissolving organic matter in a solvent, can be stored inside the head body 35. In each spinning head 33, the raw material liquid stored inside the head body 35 is ejected from the nozzles 36 onto the substrate 12. The substrate 12 is conveyed relative to each spinning head 33 by passing through the side where the raw material liquid is ejected.

[0032] Furthermore, a power source (not shown) is provided in the spinning section 22. In one example, the power source is a DC power source. The power source applies voltage to the spinning head 33 in the spinning section 22, creating a potential difference between the substrate 12 conveyed in the transport path P and the nozzle 36. Then, the raw material liquid, charged by applying voltage to the nozzle 36, is ejected from the nozzle 36 toward the substrate 12, forming a fiber film 13 of organic fibers on the surface of the substrate 12. In this embodiment, the raw material liquid from the nozzle 36 is ejected throughout the width direction of the substrate 12 conveyed along the transport direction, forming a fiber film 13 throughout the width direction of the substrate 12 on the surface of the substrate 12. In addition, the raw material liquid can be charged with either a positive or negative polarity. In addition, in this embodiment, the raw material liquid from the nozzle 36 is sprayed out along the width direction of the substrate 12 conveyed along the conveying direction and forms a fiber membrane 13 across the width direction of the surface of the substrate 12. However, if at least one end of the substrate 12 in the width direction is used as an electrode, a region where the raw material liquid is not sprayed out from the nozzle 36 and the fiber membrane 13 is not formed on the surface may be provided at the end of the substrate 12 in the width direction.

[0033] A feedstock liquid is generated by dissolving an organic substance in a solvent. The organic substance used in the feedstock liquid may be any one or more of polyolefins, polyethers, polyimides, polyketides, polysulfones, cellulose, polyvinyl alcohol, polyamides, polyamide-imides, and polyvinylidene fluoride. Examples of polyolefins include polypropylene and polyethylene.

[0034] The voltage between the nozzle 36 of each spinning head 33 and the substrate 12 is appropriately set in accordance with the type of solvent and solute in the raw material liquid, the boiling point and vapor pressure profile of the solvent in the raw material liquid, the concentration and temperature of the raw material liquid, the shape of the nozzle 36, and the distance between the substrate 12 and the nozzle 36. In one example, the voltage (potential difference) applied between the nozzle 36 of each spinning head 33 and the substrate 12 is appropriately set between 1kV and 100kV. The ejection velocity of the raw material liquid ejected from the nozzle 36 of each spinning head 33 is a value corresponding to the concentration, viscosity and temperature of the raw material liquid, the voltage applied between the nozzle 36 of each spinning head 33 and the substrate 12, and the shape of the nozzle 36.

[0035] As described above, in this embodiment, the spinning section 22 forms an organic fiber membrane 13 on the surface of the substrate 12 using an electric field spinning method (also known as charge spinning or charge-induction spinning). This forms a strip 11 where the substrate 12, which serves as an electrode (one of the anode 5 and cathode 6), and the fiber membrane 13, which serves as a spacer 7, are integrally formed. Furthermore, in one example, a voltage can be applied to either the supply source of the raw material liquid supplied to the spinning head 33 or the supply path of the raw material liquid between the supply source and the spinning head 33 using the aforementioned power source, thereby charging the raw material liquid. In this case, the charged raw material liquid is also ejected from the nozzle 36 toward the substrate 12.

[0036] Furthermore, in the spinning section 22, a fiber film 13 of organic fibers can also be formed on the surface of the substrate 12 by methods other than electric field spinning. In one example, instead of electric field spinning, the fiber film 13 of organic fibers is formed on the surface of the substrate 12 by solution jetting. In this case, in the spinning section 22, a raw material liquid in which organic substances are dissolved in a solvent is also jetted from the nozzles 36 of each of the spinning heads 33 onto the surface of the substrate 12.

[0037] Figure 5 The state of the fiber membrane 13, in which organic fibers are formed on the surface of the substrate 12 in the spinning section 22, is represented by a cross-section orthogonal or substantially orthogonal to the length direction, indicating the substrate 12 (ribbon 11). Furthermore, in Figure 5 In the context of the transport path P, the spinning head 33 is indicated by its state when viewed from either the upstream or downstream side. Figure 4 as well as Figure 5In one example, the six spinning heads 33 consist of three spinning heads 33A and three spinning heads 33B, which are different from the spinning heads 33A. The spinning heads 33A each spray the raw material liquid towards the substrate 12 from one side of the second direction of the transport path P, while the spinning heads 33B each spray the raw material liquid towards the substrate 12 from the opposite side of the spinning heads 33A in the second direction of the transport path P. As described above, the raw material liquid is sprayed towards the substrate 12 from both sides of the second direction, thus in the substrate 12 (one of the anode 5 and the cathode 6), both sides of a pair of main surfaces M are covered by a fiber membrane 13 called spacer 7.

[0038] In addition, Figure 4 as well as Figure 5 In one example, each spinning head 33 has four nozzles 36, forming a nozzle array of four nozzles 36 arranged in the first direction of the transport path P. That is, in each nozzle array of the spinning head 33, multiple nozzles 36 are arranged in the width direction (direction indicated by arrows W1 and W2) of the substrate 12 (ribbon 11). Furthermore, in... Figure 5 In the diagram, the directions indicated by arrows W1 and W2 are the width directions of the substrate 12 (strip 11), and the directions indicated by arrows T1 and T2 are the thickness directions of the substrate 12 (strip 11).

[0039] In each of the spinning heads 33, the plurality of nozzles 36 are composed of two types of nozzles 36A and 36B. Figure 4 as well as Figure 5 In one example, the spinning head 33 is equipped with two nozzles (first nozzles) 36A and two nozzles (second nozzles) 36B. In each of the spinning heads 33, nozzles 36B are arranged at both ends of the nozzle array in the second direction of the transport path P (the width direction of the substrate 12). Furthermore, in each nozzle array of the spinning head 33, nozzles 36A are arranged between nozzles 36B in the second direction of the transport path P. Therefore, in each of the spinning heads 33, nozzles 36A are arranged at the center of the nozzle array in the second direction of the transport path P (the width direction of the substrate 12).

[0040] In each of the spinning heads 33, a nozzle (first nozzle) 36A sprays raw material liquid toward the center of the substrate 12 in the width direction (first direction of the transport path P). Therefore, the center of each main surface M in the width direction of the substrate 12 is covered by the portion of the fiber membrane 13 formed by the raw material liquid sprayed from the nozzle 36A. Furthermore, in each of the spinning heads 33, a nozzle (second nozzle) 36B sprays raw material liquid toward the end of the substrate 12 in the width direction (first direction of the transport path P). Therefore, the edges E of both sides of the substrate 12 in the width direction and their vicinity are covered by the portion of the fiber membrane 13 formed by the raw material liquid sprayed from the nozzle 36B. Thus, the portions of the fiber membrane 13 that protrude outwards in the width direction from the edges E at both ends of the substrate 12 are formed by the raw material liquid sprayed from the nozzle 36B.

[0041] In each of the spinning heads 33, nozzle (second nozzle) 36B forms coarser fibers in the fiber membrane 13 compared to nozzle (first nozzle) 36A. Therefore, in the fiber membrane 13, the fiber diameter is larger in the portion formed by the raw material liquid ejected from nozzle 36B compared to the portion formed by the raw material liquid ejected from nozzle 36A. In one example, the nozzle diameter of each nozzle 36B is larger than the diameter of the nozzle outlet of each nozzle 36A. Thus, nozzle 36B forms coarser fibers compared to nozzle 36A. In another example, the concentration of organic matter dissolved in the solvent is higher in the raw material liquid ejected from nozzle 36B compared to the raw material liquid ejected from nozzle 36A. Thus, nozzle 36B forms coarser fibers compared to nozzle 36A.

[0042] Figure 6 This refers to the central portion of the strip 11 in the width direction. Figure 7 This refers to the end of the strip 11 in the width direction. Figure 6 as well as Figure 7 The images show cross-sections of the strip 11 that are orthogonal or substantially orthogonal to the width direction. In this embodiment, two nozzles 36A and 36B are used to form a fiber membrane 13 on the surface of the substrate 12 as described above. Therefore, compared to the central portion of the substrate 12 in the width direction of the strip 11, the fibers 15 in the fiber membrane 13 are thicker at the ends of the substrate 12 in the width direction of the strip 11. Consequently, compared to the central portion of the substrate 12 in the width direction of the strip 11, the diameter of the fibers 15 in the fiber membrane 13 is larger at and near the edges E of the substrate 12 in the width direction of the strip 11.

[0043] Furthermore, since the fiber membrane 13 is formed as described above, the porosity (open area ratio) of the fiber membrane 13 is higher at the ends of the strip 11 in the width direction compared to the central portion of the strip 11 in the width direction. Here, in the fiber membrane 13, the proportion of the area through which fluid can pass per specified area is defined as the porosity. That is, the proportion of the area occupied by voids per specified area is the porosity.

[0044] like Figure 4 As shown, when a fiber film 13 is formed on the surface of the substrate 12 in the spinning section 22 as described above, a strip 11, consisting of the substrate 12 and the fiber film 13, is conveyed to the surface treatment section 23. Then, in the surface treatment section 23, a surface treatment to improve the wettability of the fiber film 13 is performed. Figure 4 In one example, the surface treatment unit 23 includes an irradiator 41, which irradiates the fiber membrane 13 with ultraviolet light. As a result, oil and other components adhering to the surface of the fiber membrane 13 are removed, thereby improving the wettability of the surface of the fiber membrane 13.

[0045] Therefore, by performing surface treatment on the surface of the fiber membrane 13 by the surface treatment unit 23, the wettability of the surface of the fiber membrane 13 is improved compared to before the surface treatment. Furthermore, by improving the wettability of the surface of the fiber membrane 13 as described above, liquids can more easily adhere to the surface of the fiber membrane 13. Moreover, by performing surface treatment, the contact angle of the liquid (droplet) with respect to the surface of the fiber membrane 13 is reduced compared to before the surface treatment. Therefore, through surface treatment, the surface of the fiber membrane 13 is surface-modified to a state where liquids can easily adhere.

[0046] In one example, ozone gas is sprayed onto the surface of the fiber membrane 13 to improve its wettability. In another example, plasma is sprayed onto the surface of the fiber membrane 13 to improve its wettability. In both cases, similar to the case of irradiating the surface of the fiber membrane 13 with ultraviolet light, oil and other substances adhering to the surface of the fiber membrane 13 are removed, thereby improving the wettability of the fiber membrane 13 surface. The strip 11, whose surface of the fiber membrane 13 has been surface-treated by the surface treatment unit 23 as described above, is wound into a roller shape on the roll 32 of the winding unit 25.

[0047] In the manufacture of the electrolytic capacitor 1, when the strip 11 is formed by the manufacturing apparatus 20 as described above, the capacitor element 3 is formed using the strip 11. In the formation of the capacitor element 3, a plate member, which forms an electrode opposite in polarity to the substrate 12 (anode 5 or cathode 6), is laminated onto the strip 11, which is integrally formed with the substrate 12 (which serves as an electrode) and the fiber membrane 13 (which serves as a spacer 7). That is, the plate member, which serves as an electrode opposite in polarity to the substrate 12, is laminated relative to the substrate 12 while the fiber membrane 13 is spaced between it. At this time, the substrate 12, the fiber membrane 13, and the plate member are laminated while the substrate 12 and the plate member are electrically insulated from each other by the fiber membrane 13. Furthermore, by winding the laminate of the substrate 12, the fiber membrane 13, and the plate member, a wound body that forms the capacitor element 3 is formed. As described above, the capacitor element 3 is formed from the laminate of the substrate 12, the fiber membrane 13, and the plate member.

[0048] Then, the capacitor element 3 formed as described above is immersed in a solution containing a conductive polymer. Figure 8 This illustrates an example of the process of impregnating capacitor element 3 in a solution containing dissolved conductive polymers during the manufacture of electrolytic capacitor 1. Figure 8 In one example, a solution Y containing a dissolved conductive polymer is filled into a processing tank 42. Then, inside the processing tank 42, a capacitor element (wound body) 3 is immersed in the solution Y. The capacitor element 3 is arranged inside the processing tank 42 with the entire portion, except for the lead terminals 8 and 9, immersed in the solution Y. Examples of the dissolved conductive polymer include polyacetylene and polythiophene.

[0049] As described above, by impregnating the capacitor element 3 in solution Y, the fiber membrane 13, which serves as the spacer 7, is impregnated with a conductive polymer. The capacitor element 3 is then removed from solution Y after being impregnated for a certain period of time. Because the fiber membrane 13 is impregnated with the conductive polymer while the capacitor element 3 is immersed in solution Y, the conductive polymer remains within the spacer 7 (fiber membrane 13) in the capacitor element 3 removed from solution Y.

[0050] Furthermore, in the manufacture of the electrolytic capacitor 1, a capacitor element 3, which contains a conductive polymer impregnated in a fiber membrane 13, is housed inside a housing 2. At this time, with the lead terminals 8 and 9 extending outwards from the housing 2, the capacitor element 3 is positioned inside the housing 2. Then, an electrolyte is injected into the housing 2, impregnating the capacitor element 3 with the electrolyte. Finally, the housing 2 is sealed to maintain a tight seal, thereby forming the electrolytic capacitor 1.

[0051] In this embodiment, during the formation of the fiber membrane 13 onto the substrate 12, as described above, the fibers are formed thicker at the ends of the substrate 12 in the width direction compared to the central portion in the width direction. Therefore, the fiber membrane 13 has a higher opening ratio at the ends of the strip 11 in the width direction compared to the central portion in the width direction, allowing fluid to pass through more easily.

[0052] Here, while the coiled body serving as the capacitor element 3 is immersed in a solution Y containing dissolved conductive polymers, the conductive polymers penetrate the fiber membrane 13 from both ends of the strip 11 in the width direction. In this embodiment, the opening ratio of the fiber membrane 13 at the ends of the strip 11 in the width direction is high, so the conductive polymers penetrating towards the ends of the strip 11 in the width direction easily reach the central portion of the strip 11 in the width direction. Because the conductive polymers easily reach the central portion of the strip 11 in the width direction, in the electrolytic capacitor 1 formed as described above, it is possible to effectively prevent the distribution of conductive polymers in the fiber membrane 13, which serves as the spacer 7, from becoming uneven. That is, in the electrolytic capacitor 1, the uniformity of the distribution of conductive polymers in the fiber membrane 13 is improved.

[0053] Furthermore, in this embodiment, with the fiber membrane 13 formed on the surface of the substrate 12, a surface treatment is performed on the surface of the fiber membrane 13 to improve its wettability. Furthermore, the surface treatment improves the wettability of the fiber membrane 13 compared to before the surface treatment. By improving the wettability of the fiber membrane 13, the liquid easily adheres to the surface of the fiber membrane 13 when the capacitor element 3 is impregnated in the solution Y containing the conductive polymer. Moreover, since the liquid easily adheres to the surface of the fiber membrane 13, the conductive polymer is easily impregnated in the fiber membrane 13. Because the conductive polymer is easily impregnated in the fiber membrane 13, an appropriate amount of conductive polymer is maintained in the fiber membrane 13 in the electrolytic capacitor 1 formed as described above.

[0054] As described above, in the electrolytic capacitor 1 of this embodiment, the uniformity of the distribution of conductive polymers in the fiber membrane 13 can be improved, and an appropriate amount of conductive polymers is maintained in the fiber membrane 13. Therefore, the performance of the electrolytic capacitor 1 is improved. Furthermore, as described above, the conductive polymers easily reach the central portion of the strip 11 in the width direction, thereby improving material efficiency and other aspects in the manufacture of the electrolytic capacitor 1. As a result, labor time and costs can be reduced in the manufacture of the electrolytic capacitor 1.

[0055] Furthermore, burrs sometimes form at and near the edges E of the substrate 12. Here, in this embodiment, the fibers of the fiber membrane 13 are made coarser at the ends of the strip 11 in the width direction, as described above. Therefore, the burrs formed on the substrate 12 in the strip 11 are appropriately covered by the fiber membrane 13, effectively preventing the burrs from protruding. By effectively preventing the burrs from protruding, contact between the substrate 12 and the electrode with the opposite polarity to the substrate 12 can be effectively prevented. Thus, in the electrolytic capacitor 1, a short circuit between the anode 5 and the cathode 6 can be effectively prevented.

[0056] (Modified Example)

[0057] In addition, Figure 9 In one of the modified examples shown, a protrusion-concavity forming section 27 is provided in the manufacturing apparatus 20 for manufacturing the strip 11. The protrusion-concavity forming section 27 is located, for example, between the spinning section 22 and the surface treatment section 23 in the transport path P. When a fiber membrane 13 is formed on the surface of the substrate 12, the protrusion-concavity forming section 27 forms a protrusion-concavity shape 16 on the surface of the fiber membrane 13.

[0058] exist Figure 9 In one example, the convex-concave forming section 27 includes a pair of rollers 43. Each pair of rollers 43 has a central axis along a first direction (the width direction of the strip 11) of the conveying path P, and is capable of rotating around the central axis. Furthermore, the outer peripheral surface of each pair of rollers 43 is formed in a convex-concave shape along the circumferential direction (around the central axis), and is formed in a convex-concave shape throughout the entire circumference. The pair of rollers 43 abut against the strip from opposite sides in a second direction (the thickness direction of the strip 11) of the conveying path P, and each roller 43 abuts against the surface of the fiber membrane 13.

[0059] In the protrusion-concavity forming section 27, with the rollers 43 in contact with the conveyed strip 11, the rollers 43 are rotated in the direction of arrow R3. This forms a protrusion-concavity shape 16 on the surface of the fiber membrane 13. Figure 9 In the diagram, the left side corresponds to the upstream side of conveying path P, and the right side corresponds to the downstream side of conveying path P. Furthermore, in... Figure 9 In one example, the strip 11 passes from the upstream side to the downstream side through a pair of rollers 43, thereby forming a textured shape 16 on the surface of the fiber membrane 13.

[0060] Here, on the surface of the fiber membrane 13, a raised / lowered shape 16 is formed along the length direction of the strip 11. Furthermore, on the surface of the fiber membrane 13, the raised / lowered shape 16 is formed only at the ends of the strip 11 in the width direction. That is, the raised / lowered shape 16 is not formed at the center of the strip 11 in the width direction. Additionally, in... Figure 9In the diagram, the strip 11 is represented by its state as observed from one side of the first direction (width direction of the strip 11) of the transport path P.

[0061] When a raised / lowered shape is formed on the surface of the fiber membrane 13 in the raised / lowered forming section 27, the surface of the fiber membrane 13 is subjected to a surface treatment to improve wettability, similar to the embodiments described above, by the surface treatment section 23. Then, the surface-treated strip 11 of the fiber membrane 13 is wound up in the winding section 25. In another example, after the fiber membrane 13 is formed in the spinning section 22, the surface of the fiber membrane 13 is first surface-treated by the surface treatment section 23. Then, after the surface treatment, a raised / lowered shape 16 is formed on the surface of the fiber membrane 13 by the raised / lowered forming section 27.

[0062] In this modified example, the same function and effect are achieved as in the embodiments described above. Furthermore, in this modified example, the ends of both sides of the strip 11 in the width direction are respectively formed with concave and convex shapes 16 on the surface of the fiber membrane 13. Therefore, the ends of both sides of the strip 11 in the width direction form gaps on the surface of the fiber membrane 13 through the concave portions of the concave and convex shapes 16, further increasing the opening ratio of the fiber membrane 13. Therefore, when the capacitor element 3 is impregnated in a solution containing conductive polymers, the conductive polymers penetrating into the ends of the strip 11 in the width direction more easily reach the central portion of the strip 11 in the width direction. Thus, in the electrolytic capacitor 1 formed as described above, the uniformity of the distribution of conductive polymers in the fiber membrane 13 is further improved.

[0063] According to at least one of the above embodiments or examples, a fiber membrane serving as a spacer is formed on the surface of a substrate by spraying a raw material liquid toward a substrate that serves as an electrode. Then, during the formation of the fiber membrane, the fibers are formed thicker at the ends of the substrate in the width direction compared to the central portion in the width direction. Thus, it is possible to provide a method for manufacturing an electrolytic capacitor, an electrolytic capacitor, and an apparatus for manufacturing an electrolytic capacitor in which a fiber membrane serving as a spacer is integrally formed with one of the electrodes, and the uniformity of the conductive polymer in the fiber membrane is improved.

[0064] Several embodiments of the present invention have been described, but these embodiments are provided by way of example and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, and are included in the scope of the invention described in the claims and its equivalents.

Claims

1. A method for manufacturing an electrolytic capacitor, comprising: By spraying a raw material liquid toward a substrate that serves as an electrode, a fiber membrane serving as a spacer is formed on the surface of the substrate; and In the formation of the fiber membrane, the fibers are formed thicker at the ends of the substrate in the width direction compared to the central portion of the substrate in the width direction.

2. The method for manufacturing an electrolytic capacitor according to claim 1, wherein, It also has: With the fiber membrane formed on the surface of the substrate, a surface treatment is performed on the surface of the fiber membrane to improve its wettability.

3. The method for manufacturing an electrolytic capacitor according to claim 1 or 2, wherein, It also has: With the fiber membrane formed on the surface of the substrate, an uneven shape is formed on the surface of the fiber membrane.

4. The method for manufacturing an electrolytic capacitor according to claim 1 or 2, wherein, It also has: A plate component is formed by stacking the aforementioned fiber membranes between the fiber membranes and the substrate to create electrodes with polarities opposite to those of the substrate; a capacitor element is formed from the laminate of the substrate, the fiber membranes, and the plate component; and The capacitor element is impregnated with the conductive polymer by immersing it in a solution containing the conductive polymer.

5. An electrolytic capacitor, comprising: The substrate that becomes the electrode; and A fiber membrane, which is formed as a spacer on the surface of the substrate, has coarser fibers at the ends of the substrate in the width direction compared to the central portion of the substrate in the width direction.

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