Electrolytic capacitor manufacturing apparatus and manufacturing method

Abstract

To provide a device for manufacturing an electrolytic capacitor, in which a fiber membrane serving as a separator is formed integrally with one of a pair of electrodes, and the uniformity of conductive polymer in the fiber membrane is improved.SOLUTION: An electrolytic capacitor manufacturing device according to an embodiment includes a transport portion, a plurality of spinning heads, and a plurality of hydrophilic heads. Each of the spinning heads deposits fibers on a substrate conveyed in the transport portion, and the spinning heads are arranged at a distance from each other in the conveying direction. Each of the hydrophilic heads hydrophilizes fibers in a region where the corresponding spinning head deposits fibers, or in a region downstream and continuous with that region.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] Embodiments of the present invention relate to an electrolytic capacitor manufacturing apparatus and a manufacturing method.

Background Art

[0002] Electrolytic capacitors are widely used as capacitors. In an electrolytic capacitor, a capacitor element is housed inside a case. Further, the capacitor element is formed, for example, from a wound body in which an anode and a cathode are laminated with a separator interposed therebetween and the laminate of the anode, cathode, and separator is wound. And inside the case, the capacitor element is impregnated with an electrolytic solution. As an electrolytic capacitor, there is one in which one of a pair of electrodes (anode and cathode) is integrally formed with a separator. In the manufacture of such an electrolytic capacitor, a fiber membrane is formed as a separator on the surface of the electrode serving as a base material by discharging a raw material liquid toward the base material which is one of the pair of electrodes by a spinning method or the like.

[0003] Also, in the manufacture of an electrolytic capacitor, before immersing the wound body that becomes the capacitor element in the electrolytic solution, the wound body is immersed in a solution in which a conductive polymer is dissolved or the like to impregnate the separator with the conductive polymer. Thereby, in the electrolytic capacitor, the conductive polymer is held in the separator. In an electrolytic capacitor in which a separator is formed from a fiber membrane integral with one of a pair of electrodes as described above, it is required to improve the uniformity of the conductive polymer in the fiber membrane. For this reason, in a state where the capacitor element is immersed in the solution of the conductive polymer, it is required to appropriately impregnate not only the surface of the fiber membrane but also the inside of the fiber membrane with the conductive polymer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

[0005] The problem that the present invention aims to solve is to provide an apparatus and method for manufacturing an electrolytic capacitor in which a fibrous film that serves as a separator is formed integrally with one of a pair of electrodes, thereby improving the uniformity of the conductive polymer in the fibrous film. [Means for solving the problem]

[0006] The electrolytic capacitor manufacturing apparatus of this embodiment comprises a transport unit, a plurality of spinning heads, and a plurality of hydrophilization heads. The transport unit transports a substrate that will become an electrode. Each spinning head discharges a raw material liquid onto the substrate being transported in the transport unit, thereby depositing fibers that will form a separator fiber film onto the substrate. The plurality of spinning heads are arranged apart from each other in the transport direction in the transport unit. One or more hydrophilization heads are provided corresponding to each spinning head. Each hydrophilization head hydrophilizes the fibers in the region where the corresponding spinning head deposits fibers, or in a region that is continuous downstream of the region where the corresponding spinning head deposits fibers. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram showing an example of an electrolytic capacitor according to the first embodiment. [Figure 2] Figure 2 is a schematic diagram showing the electrolytic capacitor from Figure 1 with the capacitor element separated from the case. [Figure 3] Figure 3 is a schematic diagram showing an example of a strip-shaped body in which the anode and separator are integrated, according to the first embodiment of the electrolytic capacitor. [Figure 4] Figure 4 is a schematic diagram showing a manufacturing apparatus for producing a strip-shaped body in the first embodiment, with the second direction (width direction) of the conveying section perpendicular or approximately perpendicular to the plane of the paper. [Figure 5]Figure 5 is a schematic diagram showing an example of a process in which a capacitor element is immersed in a solution containing a dissolved conductive polymer in the manufacturing of an electrolytic capacitor according to the first embodiment. [Figure 6] Figure 6 is a schematic diagram showing a manufacturing apparatus for producing a strip-shaped material in a modified example, where the second direction (width direction) of the conveying section is perpendicular or approximately perpendicular to the plane of the paper. [Figure 7] Figure 7 is a schematic diagram showing a manufacturing apparatus for producing a strip-shaped material in a modified form of Figure 6, where the conveying direction in the conveying section is perpendicular or nearly perpendicular to the plane of the paper. [Modes for carrying out the invention]

[0008] The embodiments will be described below with reference to the drawings.

[0009] (First embodiment) Figures 1 and 2 show an example of an electrolytic capacitor 1 according to the first embodiment. As shown in Figures 1 and 2, the electrolytic capacitor 1 comprises a case 2 and a capacitor element 3 housed inside the case 2. The case 2 is made of, for example, aluminum or an aluminum alloy. Inside the case 2, the capacitor element 3 is impregnated with an electrolyte. In Figure 2, the capacitor element 3 is shown separated from the case 2.

[0010] The capacitor element 3 comprises an anode 5, a cathode 6, and a separator 7. In the capacitor element 3, the anode 5 and cathode 6 are stacked with the separator 7 in between. The capacitor element 3 is then formed from a wound body created by winding the stacked anode 5, cathode 6, and separator 7. The separator 7 has electrical insulating properties, and in the capacitor element 3, the separator 7 electrically insulates the anode 5 and cathode 6.

[0011] The anode 5 comprises a conductive metal layer and a dielectric layer formed on the surface of the metal layer. In one example, in the anode 5, the metal layer is made of aluminum or an aluminum alloy, and the dielectric layer is made of an aluminum oxide film. The cathode 6 also comprises a conductive metal layer. In one example, in the cathode 6, the metal layer is made of aluminum or an aluminum alloy. The anode-side lead terminal 8 is connected to the metal layer of the anode 5. The cathode-side lead terminal 9 is connected to the metal layer of the cathode 6. Each of the lead terminals 8 and 9 is made of a conductive metal or the like and extends to the outside of the case 2.

[0012] In the example shown in Figure 2, the separator 7 is formed integrally with the anode 5, and the fibrous film formed on the surface of the anode 5 becomes the separator 7. Figure 3 shows an example of a strip-shaped body 11 in which the anode 5 and the separator 7 are integrated. As shown in Figure 3, in the strip-shaped body 11, that is, in the substrate which becomes the anode 5 and the fibrous film which becomes the separator 7, the longitudinal direction (directions shown by arrows L1 and L2), the width direction (directions shown by arrows W1 and W2) that intersects (orthogonal or approximately orthogonal to) the longitudinal direction, and the thickness direction (directions orthogonal or approximately orthogonal to the plane of the paper in Figure 3) that intersects both the longitudinal and width directions are defined. The anode 5 has a pair of main surfaces 15, and in the anode 5, the pair of main surfaces 15 face opposite each other in the thickness direction. In the example anode 5 shown in Figure 3, both of the pair of main surfaces 15 are covered by the separator 7.

[0013] In one example, as shown in Figure 3, each of the pair of main surfaces 15 of the anode 5 is covered by the separator 7 over its entire width, and each of the two edges 16 of the anode 5 is covered by the separator 7 in the width direction, but this is not the only example. In one example, at least one of the two edges 16 of the anode 5 is not covered by the separator 7 in the width direction. In this case, the fiber film that will become the separator 7 is not formed on the surface of the anode 5, at least one of the two edges 16 in the width direction, and in its vicinity.

[0014] In one example such as FIGS. 1 to 3, a capacitor element 3 is formed by winding a laminate in which a cathode 6 is laminated on a strip 11. Further, in the capacitor element 3, the longitudinal direction of the strip 11 coincides with or substantially coincides with the circumferential direction of the wound body that becomes the capacitor element 3. And in the capacitor element 3, the width direction of the strip 11 coincides with or substantially coincides with the direction along the central axis of the wound body.

[0015] Incidentally, in one example, the separator 7 is formed integrally with the cathode 6, and the fiber membrane formed on the surface of the cathode 6 serves as the separator 7. In this case, in the same manner as the strip 11 in which the anode 5 and the separator 7 are integrated, a strip in which the fiber membrane serving as the separator 7 and the cathode 6 are integrated is formed. Then, the anode 5 is laminated on the strip in which the cathode 6 and the separator 7 are integrated, and the capacitor element 3 is formed by winding the laminate of the strip and the anode 5.

[0016] As described above, in the present embodiment, a fiber membrane serving as the separator 7 is formed integrally with a base material that is one of the pair of electrodes (anode 5 and cathode 6). Then, a plate member having a polarity opposite to that of the base material (the other one different from the base materials of the anode 5 and the cathode 6) is laminated on the strip 11, and the wound body that becomes the capacitor element 3 is formed by winding the laminate of the strip 11 and the plate member.

[0017] Hereinafter, the manufacture of the electrolytic capacitor 1 etc. will be described. In the manufacture of the electrolytic capacitor 1, a strip 11 in which a base material that is one of the pair of electrodes and a fiber membrane that serves as a separator are integrated is formed. FIG. 4 shows a manufacturing apparatus 20 for manufacturing the strip 11. The manufacturing apparatus 20 constitutes a part of the manufacturing apparatus for manufacturing the electrolytic capacitor 1. As shown in FIG. 4, the manufacturing apparatus 20 for the strip 11 includes a conveying unit 21, a plurality of spinning heads 22, a plurality of hydrophilization heads 23, a feeding unit 25, and a winding unit 26. The conveying unit (conveying path) 21 extends from the feeding unit 25 to the winding unit 26. In the manufacturing apparatus 20, a base material 12 that is one of the pair of electrodes is conveyed from the feeding unit 25 to the winding unit 26 through the conveying unit 21.

[0018] In the conveying unit 21, the conveying direction in which the base material 12 (the belt-like body 11) is conveyed, that is, the direction toward the winding unit 26, is the downstream side. And in the conveying unit 21, the direction opposite to the conveying direction, that is, the direction toward the feeding unit 25, is the upstream side. Also, in the conveying unit 21 (manufacturing apparatus 20), a first direction that intersects (is orthogonal or substantially orthogonal) to the conveying direction, and a second direction that intersects (is orthogonal or substantially orthogonal) to both the conveying direction and the first direction are defined. In an example such as FIG. 4, the second direction corresponds to the width direction of the conveying unit 21. Also, in FIG. 4, the second direction (width direction) of the conveying unit 21 is orthogonal or substantially orthogonal to the plane of the paper.

[0019] The feeding unit 25 includes a reel 31. The base material 12 is wound around the reel 31 in a roll shape. In the feeding unit 25, by driving a driving member (not shown) such as an electric motor, the reel 31 rotates in the direction of arrow R1. Thereby, the base material 12 wound around the reel 31 is fed out to the conveying unit 21. The winding unit 26 includes a reel 32. In the winding unit 26, by driving a driving member (not shown) such as an electric motor, the reel 32 rotates in the direction of arrow R2. Thereby, the base material 12 conveyed through the conveying unit 21 is wound around the reel 32 in a roll shape.

[0020] In the manufacturing apparatus 20, by rotating the reel 31 in the direction of arrow R1 and simultaneously rotating the reel 32 in the direction of arrow R2, the base material 12 is conveyed in the conveying unit 21 from the feeding unit 25 to the winding unit 26. In the conveying unit (conveying path) 21, the base material 12 (belt-like body 11) is conveyed in a state where the width direction of the base material 12 (belt-like body 11) coincides or substantially coincides with the second direction (width direction) of the conveying unit 21, and the thickness direction of the base material 12 (belt-like body 11) coincides or substantially coincides with the first direction of the conveying unit 21. In FIG. 4, the width directions of the base material 12 and the belt-like body 11 are each orthogonal or substantially orthogonal to the plane of the paper. Also, in FIG. 4, the directions indicated by arrow L1 and arrow L2 are the longitudinal direction of the base material 12 (belt-like body 11), and the directions indicated by arrow T1 and arrow T2 are the thickness direction of the base material 12 (belt-like body 11).

[0021] Furthermore, the transport section 21 may be provided with one or more guide rollers (not shown) to guide the base material 12 from the discharge section 25 to the winding section 26. In this case, the position where the guide rollers are placed in the transport section 21 is not particularly limited. Also, the extension state of the transport section (transport path) 21 from the discharge section 25 to the winding section 26 is not particularly limited. In one example, the transport section 21 is extended along the horizontal direction, and in another example, it is extended along the vertical direction. In addition, one or more bends or folds in the transport section (transport path) 21 may be provided between the discharge section 25 and the winding section 26, and the extension direction of the transport section 21 may be changed at the bends or folds.

[0022] Multiple spinning heads 22 form a fibrous film 13, which acts as a separator, on the surface of the substrate 12 being transported in the transport direction in the transport section 21. This forms a strip-shaped body 11 in which the substrate 12 and the fibrous film 13 are integrated. Each spinning head 22 is equipped with one or more nozzles 33, and in an example such as Figure 4, each spinning head 22 is provided with one nozzle 33. Each spinning head 22 can store a raw material solution, for example, in which an organic substance is dissolved in a solvent. In each spinning head 22, the raw material solution stored inside is discharged from the nozzle 33 onto the substrate 12. In the transport section 21, the substrate 12 is transported to each spinning head 22 by passing through the side from which the raw material solution is discharged.

[0023] Furthermore, the manufacturing apparatus 20 is equipped with a power supply (not shown), such as a DC power supply. The power supply applies a voltage to each of the spinning heads 22, generating a potential difference between the substrate 12 being transported in the transport section 21 and each nozzle 33 of the spinning heads 22. Then, in each of the spinning heads 22, the raw material liquid, which has been charged by the voltage applied to the nozzle 33, is discharged from the nozzle 33 toward the substrate 12, and fibers (organic fibers) are deposited on the surface of the substrate 12. By depositing fibers on the surface of the substrate 12 using multiple spinning heads 22, a fiber film 13 that acts as a separator is formed on the surface of the substrate 12. The raw material liquid may be positively charged or negatively charged.

[0024] The raw material solution is produced by dissolving an organic substance in a solvent. Examples of organic substances used in the raw material solution include one or more of the following: polyolefins, polyethers, polyimides, polyketones, polysulfones, cellulose, polyamides, polyamide-imides, and polyvinylidene fluoride. Examples of polyolefins include polypropylene and polyethylene. Furthermore, the organic substances used in the raw material solution are poorly soluble in solutions containing conductive polymers, as described later.

[0025] The voltage between each nozzle 33 of the spinning head 22 and the substrate 12 is set appropriately according to the type of solvent and solute in the raw material solution, the boiling point and vapor pressure curve of the solvent in the raw material solution, the concentration and temperature of the raw material solution, the shape of the nozzle 33, and the distance between the substrate 12 and the nozzle 33. In one example, the voltage (potential difference) applied between each nozzle 33 of the spinning head 22 and the substrate 12 is set appropriately between 1kV and 100kV. The discharge speed of the raw material solution from each nozzle 33 of the spinning head 22 is determined by the concentration, viscosity and temperature of the raw material solution, the voltage applied between each nozzle 33 of the spinning head 22 and the substrate 12, and the shape of the nozzle 33.

[0026] As described above, in this embodiment, multiple spinning heads 22 form a fiber film 13 on the surface of the substrate 12 by electrospinning (also referred to as charge spinning or charge induction spinning, etc.). This forms a strip-shaped body 11 in which the substrate 12, which serves as an electrode (one of the anode 5 and cathode 6), and the fiber film 13, which serves as a separator 7, are integrated. In one example, a voltage may be applied by the aforementioned power supply, etc., to either the raw material liquid supply source to the spinning head 22 or the raw material liquid supply path between the supply source and the spinning head 22, thereby charging the raw material liquid. In this case as well, the charged raw material liquid is discharged from each nozzle 33 of the spinning head 22 toward the substrate 12.

[0027] The formation of an organic fiber film 13 on the surface of the substrate 12 by multiple spinning heads 22 may be carried out by a method other than electrospinning. In one example, instead of electrospinning, the organic fiber film 13 is formed on the surface of the substrate 12 by a solution blowing method. In this case as well, a raw material solution in which an organic substance is dissolved in a solvent is discharged from each nozzle 33 of the spinning head 22 onto the surface of the substrate 12, thereby depositing fibers on the surface of the substrate 12.

[0028] In the example manufacturing apparatus 20 shown in Figure 4, a plurality of spinning heads 22 are provided, consisting of a plurality of spinning heads 22A and a plurality of spinning heads 22B. Each of the spinning heads 22A discharges the raw material liquid toward the substrate 12 from one side in the first direction (thickness direction of the substrate 12) of the conveying unit 21. Each of the spinning heads 22B discharges the raw material liquid toward the substrate 12 from the opposite side of the first direction of the conveying unit 21 from the spinning heads 22A. In the example shown in Figure 4, as described above, since the raw material liquid is discharged toward the substrate 12 from both sides in the first direction (thickness direction of the substrate 12), both of the pair of main surfaces 15 of the substrate 12 (one of the anode 5 and cathode 6) are covered by the fiber membrane 13 which serves as the separator 7. In the substrate 12, one of the pair of main surfaces 15 is designated as the main surface (first main surface) 15A, and the other of the pair of main surfaces 15 is designated as the main surface (second main surface) 15B.

[0029] Furthermore, in the example shown in Figure 4, the multiple spinning heads 22A are arranged apart from each other in the transport direction in the transport section 21, and the multiple spinning heads 22B are also arranged apart from each other in the transport direction. Therefore, in the example shown in Figure 4, in each of the multiple regions that are separated from each other in the transport direction, fibers are deposited on the main surface 15A of the base material 12 by the corresponding spinning heads 22A. Then, in each of the multiple regions that are separated from each other in the transport direction, fibers are deposited on the main surface 15B of the base material 12 by the corresponding spinning heads 22B.

[0030] Each of the multiple hydrophilization heads 23 hydrophilizes the fibers deposited on the surface of the substrate 12. In the hydrophilization treatment of fibers using multiple hydrophilization heads 23, for example, ultraviolet light is irradiated from each of the hydrophilization heads 23 onto the fibers deposited on the substrate 12. As a result, a portion of the fibers is oxidized, improving the hydrophilicity (wettability) of the fibers. When irradiating the fibers with ultraviolet light, an element that generates ultraviolet light is provided inside each of the hydrophilization heads 23, or ultraviolet light generated by the element that generates ultraviolet light is guided to each of the hydrophilization heads 23. Then, ultraviolet light is irradiated from each of the hydrophilization heads 23 onto the fibers on the surface of the substrate 12, and a portion of the fibers is oxidized by the generation of ozone and reactive oxygen species. Alternatively, the chemical bonds of a portion of the fibers are broken, and they are oxidized by the generated reactive oxygen species.

[0031] In one example, each of the hydrophilic heads 23 improves the hydrophilicity of the fibers deposited on the substrate 12 by spraying ozone gas onto the fibers. In another example, the hydrophilicity of the fibers is improved by spraying atmospheric pressure plasma onto the fibers deposited on the substrate 12. In both cases, similar to when ultraviolet light is irradiated onto the fibers, a portion of the fibers is oxidized by the generated reactive oxygen species, improving the hydrophilicity (wettability) of the fibers. The hydrophilic heads 23 may be subjected to appropriate combinations of the hydrophilicity-improving treatments exemplified above. Furthermore, when a voltage is applied to the spinning heads 22 to discharge the raw material liquid from each of the spinning heads 22, it is preferable that each of the hydrophilic heads 23 be made of an electrically insulating material. This reduces the influence of the hydrophilic heads 23 on the electric field generated by the application of voltage to the spinning heads 22. As described above, after processing by multiple spinning heads 22 and multiple hydrophilizing heads 23, the strip-shaped body 11, on which a fiber film 13 has been formed on the surface (each of the main surfaces 15) of the base material 12, is wound into a roll on the reel 32 of the winding unit 26.

[0032] In the example shown in Figure 4, a plurality of hydrophilic heads 23 are provided, consisting of a plurality of hydrophilic heads 23A and a plurality of hydrophilic heads 23B. Each hydrophilic head 23A hydrophilizes the fibers deposited on the main surface 15A of the substrate 12, and each hydrophilic head 23B hydrophilizes the fibers deposited on the main surface 15B of the substrate 12. One or more hydrophilic heads 23A are provided corresponding to each of the plurality of spinning heads 22A, and in the example shown in Figure 4, one hydrophilic head 23A is provided corresponding to each of the spinning heads 22A. Similarly, one or more hydrophilic heads 23B are provided corresponding to each of the plurality of spinning heads 22B, and in the example shown in Figure 4, one hydrophilic head 23B is provided corresponding to each of the spinning heads 22B.

[0033] In the manufacturing apparatus 20, each of the multiple hydrophilizing heads 23A is positioned downstream of the conveying section 21 relative to the corresponding spinning head 22A. Therefore, in the manufacturing apparatus 20, the spinning heads 22A and hydrophilizing heads 23A are arranged alternately along the conveying direction in the conveying section 21. Furthermore, as described above, because the spinning heads 22A and hydrophilizing heads 23A are arranged, each hydrophilizing head 23A hydrophilizes the fibers deposited on the substrate 12 in a region that is continuous downstream of the region where the corresponding spinning head 22A deposits fibers. Therefore, in the conveying section 21, along the conveying direction, that is, from upstream to downstream, regions where fibers are deposited by the spinning heads 22A and regions where fibers are hydrophilized by the hydrophilizing heads 23A are repeatedly and alternately formed. Therefore, as the substrate 12 is transported downstream, the main surface 15A of the substrate 12 repeatedly alternates between the deposition of fibers by the spinning head 22A and the hydrophilization of fibers by the hydrophilization head 23A.

[0034] Furthermore, in the manufacturing apparatus 20, each of the multiple hydrophilizing heads 23B is positioned downstream of the conveying section 21 relative to the corresponding spinning head 22B. Therefore, in the manufacturing apparatus 20, the spinning heads 22B and hydrophilizing heads 23B are arranged alternately along the conveying direction in the conveying section 21. Also, as described above, because the spinning heads 22B and hydrophilizing heads 23B are arranged, each hydrophilizing head 23B hydrophilizes the fibers deposited on the substrate 12 in a region that is continuous downstream of the region where the corresponding spinning head 22B deposits fibers. Therefore, in the conveying section 21, along the conveying direction, that is, from upstream to downstream, regions where fibers are deposited by the spinning heads 22B and regions where fibers are hydrophilized by the hydrophilizing heads 23B are alternately and repeatedly formed. Therefore, as the substrate 12 is transported downstream, the main surface 15B of the substrate 12 alternately performs fiber deposition by the spinning head 22B and hydrophilization of the fibers by the hydrophilization head 23B.

[0035] In the manufacturing of the electrolytic capacitor 1, once the strip-shaped body 11 is formed by the manufacturing apparatus 20 as described above, a capacitor element 3 is formed using the strip-shaped body 11. In the formation of the capacitor element 3, a plate member that will be an electrode with the opposite polarity to the base material 12 is laminated onto the strip-shaped body 11, which is an integral part of the base material 12 that will be an electrode (anode 5 or cathode 6) and the fiber film 13 that will be a separator 7. That is, a plate member that will be an electrode with the opposite polarity to the base material 12 is laminated onto the base material 12 with the fiber film 13 in between. At this time, the base material 12, the fiber film 13 and the plate member are laminated while the base material 12 and the plate member are electrically insulated from each other by the fiber film 13. Then, by winding the laminate of the base material 12, the fiber film 13 and the plate member, a wound body that will become the capacitor element 3 is formed. As described above, the capacitor element 3 is formed from a laminate of the base material 12, the fiber film 13 and the plate member.

[0036] Then, the capacitor element 3 formed as described above is immersed in a solution in which a conductive polymer is dissolved. Figure 5 shows an example of the process of immersing the capacitor element 3 in a solution in which a conductive polymer is dissolved in the manufacturing of an electrolytic capacitor 1. In the example in Figure 5, a processing tank 41 is filled with a solution 42 in which a conductive polymer is dissolved. Then, inside the processing tank 41, the capacitor element (winding body) 3 is immersed in the filled solution 42. The capacitor element 3 is placed inside the processing tank 41 so that the entire part of it, except for the lead terminals 8 and 9, is immersed in the solution 42.

[0037] Examples of conductive polymers to be dissolved include polyacetylene and polythiophenes. The solution in which the conductive polymer is dissolved becomes acidic, for example, with a pH of about 3. Furthermore, as mentioned above, the organic substances used in the raw material solution for forming the fiber film 13 are difficult to dissolve in the solution in which the conductive polymer is dissolved. For this reason, when the capacitor element 3 is immersed in the conductive polymer solution, the dissolution of the fibers forming the fiber film 13 into the conductive polymer solution is effectively suppressed.

[0038] As described above, when the capacitor element 3 is immersed in the solution 42, the conductive polymer impregnates the fiber film 13 which forms the separator 7. After immersing the capacitor element 3 in the solution 42 for a certain period of time, it is removed from the solution 42. As described above, the conductive polymer impregnates the fiber film 13 when the capacitor element 3 is immersed in the solution 42, so when the capacitor element 3 is removed from the solution 42, the conductive polymer is retained in the separator 7 (fiber film 13).

[0039] Furthermore, in the manufacture of the electrolytic capacitor 1, a capacitor element 3, in which a conductive polymer is impregnated into a fiber film 13, is housed inside the case 2. At this time, the capacitor element 3 is positioned inside the case 2 with lead terminals 8 and 9 extending to the outside of the case 2. Then, an electrolyte is injected into the inside of the case 2 to impregnate the capacitor element 3 with the electrolyte. Finally, the case 2 is sealed, and the inside of the case 2 is sealed, thereby forming the electrolytic capacitor 1.

[0040] Furthermore, the aforementioned manufacturing apparatus 20 is provided with a control unit 27 that controls the entire manufacturing apparatus 20. The control unit 27 includes a processor or integrated circuit (control circuit) including a CPU (Central Processing Unit), ASIC (Application Specific Integrated Circuit), or FPGA (Field Programmable Gate Array), and a storage medium such as memory. The control unit 27 may have only one integrated circuit or may have multiple integrated circuits. The control unit 27 performs processing by executing a program stored in the storage medium. In the manufacturing apparatus 20, the control unit 27 controls the operation of the transport unit 21, the spinning head 22, and the hydrophilization head 23, etc. This controls the transport of the base material 12 in the transport unit 21, the discharge of raw material liquid from each of the spinning heads 22, and the hydrophilization processing by each of the hydrophilization heads 23.

[0041] As described above, in this embodiment, each of the hydrophilic heads 23 hydrophilizes the fibers in a region that is continuous downstream of the region where the corresponding spinning head 22 deposits fibers. Then, in the conveying section 21 of the manufacturing apparatus 20, the region where fibers are deposited by the spinning head 22 and the region where fibers are hydrophilized by the hydrophilic heads 23 are alternately formed along the conveying direction. That is, on the surface of the substrate 12 conveyed in the conveying section 21, fiber deposition and fiber hydrophilization are alternately and repeatedly performed. As described above, since the fibers are hydrophilized, the hydrophilicity of the fibers is improved not only on the surface but also internally in the fiber film 13 formed from the fibers deposited on the substrate 12.

[0042] In this comparative example, a configuration in which fibers are deposited on the surface of the substrate by a spinning head, etc., only upstream of the region to be hydrophilized in the transport section is considered. In the comparative example, the hydrophilization treatment of the fibers is performed only when a fiber film is formed on the surface of the substrate 12. On the other hand, in this embodiment, as described above, fiber deposition and fiber hydrophilization are repeated alternately, so the hydrophilicity of the fibers inside the formed fiber film 13 is higher than in the comparative example, etc.

[0043] As described above, in this embodiment, the hydrophilicity of the fibers in the fiber film 13 formed on the substrate 12 is increased not only on the surface but also inside. Therefore, when the capacitor element 3 is immersed in the conductive polymer solution as described above, the conductive polymer is properly impregnated into the fiber film 13 that becomes the separator 7, not only on the surface but also inside. Because the conductive polymer is impregnated into the inside of the fiber film 13, the uneven distribution of the conductive polymer in the fiber film 13 that becomes the separator 7 in the electrolytic capacitor 1 formed as described above is effectively prevented. In other words, the uniformity of the conductive polymer in the fiber film 13 (separator 7) is improved in the electrolytic capacitor 1.

[0044] Furthermore, in this embodiment, as described above, the fibers are made hydrophilic, so the hydrophilicity of the fibers is improved both on the surface and inside the fiber film 13. The improved hydrophilicity of the fibers on the surface of the fiber film 13 makes it easier for the liquid to adhere to the surface of the fiber film 13 when the capacitor element 3 is immersed in a solution containing the dissolved conductive polymer. This increased adhesion of the liquid to the surface of the fiber film 13 facilitates further impregnation of the fiber film 13 with the conductive polymer.

[0045] As described above, in the electrolytic capacitor 1 of this embodiment, the uniformity of the conductive polymer in the fiber film 13 is improved. As a result, the performance of the electrolytic capacitor 1 is improved. In addition, because the conductive polymer is more easily impregnated into the interior of the fiber film 13, material efficiency and other factors are improved in the manufacturing of the electrolytic capacitor 1. This makes it possible to reduce labor and costs in the manufacturing of the electrolytic capacitor 1.

[0046] (modified version) In addition, in a modified example shown in Figures 6 and 7, the multiple spinning heads 22A are arranged apart from each other in the transport direction in the transport section 21, and the multiple spinning heads 22B are also arranged apart from each other in the transport direction. Therefore, in this modified example as well, in each of the multiple regions that are separated from each other in the transport direction, fibers are deposited on the main surface 15A of the base material 12, and in each of the multiple regions that are separated from each other in the transport direction, fibers are deposited on the main surface 15B of the base material 12. Furthermore, in this modified example, a pair (two) of hydrophilic heads 23A are provided corresponding to each spinning head 22A, and a pair (two) of hydrophilic heads 23B are provided corresponding to each spinning head 22B.

[0047] In this modified example, as described above, the transport direction, the first direction, and the second direction are defined in the transport unit 21 (manufacturing apparatus 20). In the transport unit 21, the substrate 12 (strip-shaped body 11) is transported such that the width direction of the substrate 12 coincides with or approximately coincides with the second direction, and the thickness direction of the substrate 12 coincides with or approximately coincides with the first direction. Here, in Figure 6, the second direction (width direction) of the transport unit 21 is perpendicular or approximately perpendicular to the plane of the paper. Also, in Figure 7, the transport direction in the transport unit 21 is perpendicular or approximately perpendicular to the plane of the paper.

[0048] In this modified example, each of the multiple hydrophilizing heads 23A is positioned relative to the corresponding spinning head 22A without or with minimal displacement in the transport direction of the transport unit 21. Because the spinning head 22A and the hydrophilizing heads 23A are positioned in this manner, each of the hydrophilizing heads 23A hydrophilizes the fibers deposited on the substrate 12 in the region where the corresponding spinning head 22A deposits fibers. Therefore, in the transport unit 21, both fiber deposition by the spinning head 22A and hydrophilization of fibers by the hydrophilizing heads 23A occur in each of the multiple regions that are separated from each other in the transport direction. That is, both fiber deposition by the spinning head 22A and hydrophilization of fibers by the hydrophilizing heads 23A occur on the main surface 15A of the substrate 12 in each of the multiple regions that are separated from each other in the transport direction.

[0049] Furthermore, in the modified manufacturing apparatus 20, each of the multiple hydrophilizing heads 23B is positioned with respect to the corresponding spinning head 22B without or with minimal displacement in the conveying direction in the conveying section 21. Because the spinning heads 22B and hydrophilizing heads 23B are positioned in this manner, each of the hydrophilizing heads 23B hydrophilizes the fibers deposited on the substrate 12 in the region where the corresponding spinning head 22B deposits fibers. For this reason, in the conveying section 21, both fiber deposition by the spinning heads 22B and hydrophilization of fibers by the hydrophilizing heads 23B occur in each of the multiple regions that are separated from each other in the conveying direction. That is, both fiber deposition by the spinning heads 22B and hydrophilization of fibers by the hydrophilizing heads 23B occur on the main surface 15B of the substrate 12 in each of the multiple regions that are separated from each other in the conveying direction.

[0050] Furthermore, in this modified example, each of the hydrophilic heads 23A is positioned offset from the corresponding spinning head 22A in the second direction of the transport unit 21 (the width direction of the base material 12). In the example shown in Figures 6 and 7, each of the spinning heads 22A is positioned between a pair of corresponding hydrophilic heads 23A in the second direction of the transport unit 21, and each of the hydrophilic heads 23A is positioned side by side in the second direction with respect to the corresponding spinning head 22A. Therefore, in the configuration in which fibers are hydrophilized by ultraviolet irradiation, the position from which ultraviolet light is emitted from each of the hydrophilic heads 23A is offset from the position from which the raw material liquid is discharged from the corresponding spinning head 22A in the second direction of the transport unit 21. And, in the configuration in which fibers are hydrophilized by jetting atmospheric pressure plasma or ozone gas, the position from which atmospheric pressure plasma or ozone gas is ejected from each of the hydrophilic heads 23A is offset from the position from which the raw material liquid is discharged from the corresponding spinning head 22A in the second direction of the transport unit 21.

[0051] Similarly, in this modified example, each of the hydrophilic heads 23B is positioned offset from the corresponding spinning head 22B in the second direction of the transport unit 21 (the width direction of the substrate 12). In the example shown in Figures 6 and 7, each of the spinning heads 22B is positioned between a pair of corresponding hydrophilic heads 23B in the second direction of the transport unit 21, and each of the hydrophilic heads 23B is positioned side by side in the second direction with respect to the corresponding spinning head 22B. Therefore, in the configuration in which fibers are hydrophilized by ultraviolet irradiation, the position from which ultraviolet light is emitted from each of the hydrophilic heads 23B is offset from the position from which the raw material liquid is discharged from the corresponding spinning head 22B in the second direction of the transport unit 21. And in the configuration in which fibers are hydrophilized by jetting atmospheric pressure plasma or ozone gas, the position from which atmospheric pressure plasma or ozone gas is ejected from each of the hydrophilic heads 23B is offset from the position from which the raw material liquid is discharged from the corresponding spinning head 22B in the second direction of the transport unit 21.

[0052] In the example shown in Figure 7, a corresponding hydrophilic head 23A is arranged on both sides of each spinning head 22A in the second direction, but this is not limited to this. In one example, a corresponding hydrophilic head 23A may be arranged on only one side of each spinning head 22A in the second direction. Similarly, in the example shown in Figure 7, a corresponding hydrophilic head 23B is arranged on both sides of each spinning head 22B in the second direction, but this is not limited to this. In one example, a corresponding hydrophilic head 23B may be arranged on only one side of each spinning head 22B in the second direction.

[0053] As described above, in this modified example, each of the hydrophilizing heads 23 hydrophilizes the fibers in the region where the corresponding spinning head 22 deposits the fibers. Then, in the conveying section 21 of the manufacturing apparatus 20, both the hydrophilization of the fibers by the spinning head 22 and the hydrophilization of the fibers by the hydrophilizing heads 23 are performed in each of the multiple regions that are separated from each other in the conveying direction. As described above, the fibers are hydrophilized, so in this modified example as well, the hydrophilicity of the fibers is improved not only on the surface but also internally in the fiber film 13 formed from the fibers deposited on the substrate 12.

[0054] In this modified example, the hydrophilicity of the fibers in the fiber film 13 formed on the substrate 12 is increased not only on the surface but also internally. Therefore, when the capacitor element 3 is immersed in the conductive polymer solution as described above, the conductive polymer is properly impregnated into the fiber film 13, which becomes the separator 7, not only on the surface but also internally. As a result, even in the electrolytic capacitor 1 manufactured as in this modified example, the uniformity of the conductive polymer in the fiber film 13 (separator 7) is improved. Therefore, in this modified example, the performance of the electrolytic capacitor 1 is improved, and the effort and cost in manufacturing the electrolytic capacitor 1 can be reduced.

[0055] Furthermore, in this modified example, each of the spinning heads 22 discharges the raw material liquid toward the substrate 12 from a first direction intersecting the conveying direction. Each of the hydrophilizing heads 23 is positioned offset from the corresponding spinning head 22 in a second direction intersecting both the conveying direction and the first direction. This makes it easy to realize a configuration in which each of the hydrophilizing heads 23 hydrophilizes the fibers in the region where the corresponding spinning head 22 deposits fibers.

[0056] According to at least one of these embodiments or examples, one or more hydrophilizing heads are provided corresponding to each of the plurality of spinning heads, and each hydrophilizing head is provided in the region where the corresponding spinning head deposits fibers, or in a region continuous downstream of the region where the corresponding spinning head deposits fibers. This makes it possible to provide an electrolytic capacitor manufacturing apparatus in which a fiber film that acts as a separator is formed integrally with one of the pair of electrodes, thereby improving the uniformity of the conductive polymer in the fiber film.

[0057] According to at least one embodiment or example, the fibers are made hydrophilic in each of the multiple regions where the fibers are deposited, or in a region that is continuous downstream of each of the multiple regions where the fibers are deposited. This forms a fiber film that acts as a separator integrally with one of the pair of electrodes, and provides a method for manufacturing an electrolytic capacitor that improves the uniformity of the conductive polymer in the fiber film.

[0058] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, 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, as well as in the claims of the invention and its equivalents. The following are additional notes. [1] A transport unit for transporting the substrate that will become the electrode, In the conveying section, each spinning head discharges a raw material liquid onto the substrate being conveyed, thereby depositing fibers on the substrate that form a separator fiber film, and a plurality of spinning heads are arranged apart from each other in the conveying direction in the conveying section, One or more hydrophilizing heads are provided corresponding to each of the multiple spinning heads, and each hydrophilizing head makes the fibers hydrophilic in the region where the corresponding spinning head deposits the fibers, or in a region that is continuous downstream of the region where the corresponding spinning head deposits the fibers, A manufacturing apparatus for electrolytic capacitors, equipped with the following features. [2] Each of the plurality of spinning heads discharges the raw material liquid toward the substrate from one side in a first direction intersecting the transport direction, Each of the plurality of hydrophilic heads is positioned offset from the corresponding spinning head in a second direction that intersects both the transport direction and the first direction. [1] Manufacturing equipment. [3] A manufacturing apparatus according to [1] or [2], wherein each of the plurality of hydrophilizing heads hydrophilizes the fibers by at least one of irradiating the fibers with ultraviolet light, spraying the fibers with atmospheric pressure plasma, and spraying the fibers with ozone gas. [4] Transporting the substrate that will become the electrode in the transport section, In each of the multiple regions in the transport section that are separated from each other in the transport direction, the raw material liquid is discharged onto the transported substrate, thereby depositing fibers that form a separator fiber film onto the substrate. To make the fibers hydrophilic in each of the plurality of regions where the fibers are deposited, or in a region that is continuous downstream of each of the plurality of regions where the fibers are deposited, A method for manufacturing an electrolytic capacitor, comprising the following: [5] The method for making the fibers hydrophilic, wherein the fibers are made hydrophilic by irradiating the fibers with ultraviolet light, spraying atmospheric pressure plasma onto the fibers, and spraying ozone gas onto the fibers. [6] A plate member having an electrode with opposite polarity to the substrate is laminated to the substrate with the fiber film in between, and a capacitor element is formed from the laminate of the substrate, the fiber film and the plate member. Impregnating the fiber film with a conductive polymer, A method for manufacturing [4] or [5], further comprising: [Explanation of symbols]

[0059] 1... Electrolytic capacitor, 2... Case, 3... Capacitor element, 5... Anode, 6... Cathode, 7... Separator, 11... Strip, 12... Substrate, 13... Fiber film, 20... Manufacturing equipment, 21... Conveying unit, 22 (22A, 22B)... Spinning head, 23 (23A, 23B)... Hydrophilization head.

Claims

1. A transport unit that transports the substrate that will become the electrode, In the conveying section, each spinning head discharges a raw material liquid onto the substrate being conveyed, thereby depositing fibers on the substrate that form a separator fiber film, and a plurality of spinning heads are arranged apart from each other in the conveying direction in the conveying section, One or more hydrophilizing heads are provided corresponding to each of the multiple spinning heads, and each hydrophilizing head makes the fibers hydrophilic in the region where the corresponding spinning head deposits the fibers, or in a region that is continuous downstream of the region where the corresponding spinning head deposits the fibers. A manufacturing apparatus for electrolytic capacitors, equipped with the following features.

2. Each of the multiple spinning heads discharges the raw material liquid toward the substrate from one side in a first direction intersecting the transport direction. Each of the plurality of hydrophilic heads is positioned offset from the corresponding spinning head in a second direction that intersects both the transport direction and the first direction. The manufacturing apparatus according to claim 1.

3. The manufacturing apparatus according to claim 1 or 2, wherein each of the plurality of hydrophilizing heads hydrophilizes the fibers by at least one of irradiating the fibers with ultraviolet light, spraying the fibers with atmospheric pressure plasma, and spraying the fibers with ozone gas.

4. In the transport section, the substrate that will become the electrode is transported, In each of the multiple regions in the transport section that are separated from each other in the transport direction, the raw material liquid is discharged onto the transported substrate, thereby depositing fibers that form a separator fiber film onto the substrate. Using one or more hydrophilic heads provided corresponding to each of the plurality of regions where the fibers are deposited, the fibers are made hydrophilic in a corresponding region among the plurality of regions where the fibers are deposited, or in a region that is continuous downstream of the corresponding region among the plurality of regions where the fibers are deposited. A method for manufacturing an electrolytic capacitor, comprising the following:

5. The manufacturing method of claim 4, wherein the fibers are made hydrophilic by irradiating the fibers with ultraviolet light, spraying atmospheric pressure plasma onto the fibers, and spraying ozone gas onto the fibers.

6. A plate member, which serves as an electrode with opposite polarity to the substrate, is laminated to the substrate with the fiber film in between, thereby forming a capacitor element from the laminate of the substrate, the fiber film, and the plate member. Impregnating the fiber film with a conductive polymer, The manufacturing method of claim 4 or 5, further comprising

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