Manufacturing method for pellets for electrolytic capacitors, manufacturing method for electrolytic capacitors, and manufacturing device for pellets for electrolytic capacitors

Abstract

To suppress a leakage current and a short circuit.SOLUTION: A manufacturing method of an electrolytic capacitor pellet disclosed herein includes a filling step of filling a compression space 55 with a powder 41 containing a valve metal, a first compression step of compressing the powder 41 in the first direction D1 by narrowing the compression space 55 in the first direction D1, and a second compression step of compressing the powder 41 in the second direction D2 by narrowing the compression space 55 in the second direction D2 intersecting the first direction D1 after the first compression step.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing pellets for electrolytic capacitors, a method for manufacturing electrolytic capacitors, and an apparatus for manufacturing pellets for electrolytic capacitors. [Background technology]

[0002] Conventionally, a method for obtaining a capacitor element of an electrolytic capacitor is known that includes a compression step of compressing a powder containing a valve metal such as tantalum or niobium, and a sintering step of sintering the compressed powder (for example, Patent Document 1). In the compression step of Patent Document 1, a powder containing a valve metal is filled into a space between a pair of punches, and is compressed by applying pressure with the pair of punches. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-153625 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the powder is compressed in one direction as in Patent Document 1, the powder density varies in the sintered body of the resulting capacitor element. Typically, in the thickness direction of the sintered body, both end regions are dense, while the central region is sparse. The inventors of the present application have found that such variations in powder density increase leakage current and increase the frequency of short circuit failures. In this situation, one of the objectives of the present disclosure is to suppress leakage current and short circuit failures. [Means for solving the problem]

[0005] One aspect of the present disclosure relates to a method for producing pellets for electrolytic capacitors, the method including: a filling step of filling a compression space with a powder containing a valve metal, a first compression step of compressing the powder in a first direction by narrowing the compression space in the first direction, and a second compression step of compressing the powder in the second direction by narrowing the compression space in a second direction intersecting the first direction after the first compression step.

[0006] Another aspect of the present disclosure relates to a method for producing an electrolytic capacitor, the method including a sintering step of sintering electrolytic capacitor pellets produced by the method for producing electrolytic capacitor pellets described above.

[0007] Another aspect of the present disclosure relates to an apparatus for manufacturing pellets for electrolytic capacitors, the apparatus comprising a pair of first movable members and a pair of second movable members defining a compression space to be filled with a powder containing a valve metal, the pair of first movable members being movable in a first direction to expand and contract the compression space, the pair of second movable members being movable in a second direction intersecting the first direction to expand and contract the compression space, and a control unit for moving the pair of first movable members in the first direction to narrow the compression space, and then moving the pair of second movable members in the second direction to further narrow the compression space. Effect of the Invention

[0008] According to the present disclosure, leakage current and short circuit defects can be suppressed. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view that illustrates a manufacturing apparatus for electrolytic capacitor pellets according to a first embodiment. [Diagram 2] FIG. 2 is a plan view showing the operation of the manufacturing apparatus for electrolytic capacitor pellets according to the first embodiment. [Diagram 3] 1 is a cross-sectional view illustrating a schematic diagram of an electrolytic capacitor according to a first embodiment. [Figure 4]FIG. 11 is a plan view showing the operation of the manufacturing apparatus for electrolytic capacitor pellets according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The following describes an embodiment of a method for manufacturing electrolytic capacitor pellets, a method for manufacturing electrolytic capacitors, and an apparatus for manufacturing electrolytic capacitor pellets according to the present disclosure. However, the present disclosure is not limited to the examples described below. In the following description, specific numerical values ​​and materials may be exemplified, but other numerical values ​​and materials may be applied as long as the effects of the present disclosure are obtained.

[0011] (Method of manufacturing electrolytic capacitor pellets) The method for producing pellets for electrolytic capacitors (hereinafter also simply referred to as pellets) according to the present disclosure includes a filling step, a first compression step, and a second compression step.

[0012] In the filling step, a powder containing a valve metal (hereinafter, simply referred to as powder) is filled into the compression space. The valve metal may be, for example, aluminum, tantalum, or niobium. The powder may be composed of an alloy made of one or more metals. For example, an alloy containing a valve metal and silicon, vanadium, boron, or the like may be used. Alternatively, the powder may be composed of a compound containing a valve metal and a typical element such as nitrogen. The particle size of the powder may be, for example, 0.01 μm or more and 10 μm or less.

[0013] In the first compression step, the powder is compressed in the first direction by narrowing the compression space in the first direction. The magnitude of the force applied to the powder at this time is not particularly limited, but may be, for example, 10 N or more and 100 N or less.

[0014] The second compression step is performed after the first compression step. In the second compression step, the compression space is narrowed in the second direction to compress the powder in the second direction. The second direction is a direction intersecting the first direction, and may be, for example, a direction perpendicular to the first direction. The magnitude of the force applied to the powder in the second compression step is not particularly limited, and may be, for example, 10 N or more and 100 N or less.

[0015] As described above, in the pellet manufacturing method according to the present disclosure, the powder is compressed not only in one direction but in two directions (i.e., the first direction and the second direction). Here, when the powder is compressed in only one direction, variations in powder density are likely to occur along that one direction. In contrast, when the powder is compressed in two directions, such variations in powder density are unlikely to occur. Therefore, in an electrolytic capacitor including a pellet manufactured by this manufacturing method, leakage current and short circuit defects can be suppressed.

[0016] Furthermore, in the pellet manufacturing method according to the present disclosure, compression in the first direction is followed by compression in the second direction. Therefore, the powder is more likely to move freely in the compression space in the first direction compared to the case where compression in the first direction and compression in the second direction are performed simultaneously. In this way, by appropriately setting the first direction in which compression is performed with a relatively high degree of freedom of movement of the powder and the second direction in which compression is performed with a relatively low degree of freedom of movement of the powder, it is possible to control the density of the powder in the pellet.

[0017] The first direction may be a width direction intersecting with the thickness direction of the pellet, and the second direction may be a thickness direction of the pellet, and the pellet may have a dimension in the thickness direction less than or equal to the dimension in the width direction. According to this configuration, compression is performed in a state where the powder has a high degree of freedom of movement in the width direction of the pellet. In this compression process, the powder moves freely in the thickness direction of the pellet intersecting with the width direction. Therefore, the powder is less likely to have a sparse or dense distribution, particularly in the thickness direction of the pellet. The pellet may have a dimension in the thickness direction less than the dimension in the width direction.

[0018] The first direction may be the thickness direction of the pellet, and the second direction may be the width direction intersecting with the thickness direction of the pellet, and the pellet may have a dimension in the thickness direction that is equal to or smaller than the dimension in the width direction. According to this configuration, compression is performed in a state where the powder has a high degree of freedom of movement in the thickness direction of the pellet. In this compression process, the powder moves freely in the width direction of the pellet that intersects with the thickness direction. Therefore, the powder is less likely to have a sparse or dense distribution, particularly in the width direction of the pellet. The pellet may have a dimension in the thickness direction that is smaller than the dimension in the width direction.

[0019] The method for producing pellets may further include a third compression step of further compressing the powder by narrowing the compression space in at least one of the first and second directions after the second compression step. In the third compression step, compression in the first direction, compression in the second direction, or compression in both the first and second directions may be performed. Note that the method for producing pellets does not necessarily have to include such a third compression step.

[0020] The method for producing the pellet may further include a lead arrangement step of arranging a part of a lead extending in a third direction intersecting the first and second directions in the compression space before the first compression step. The lead arranged in the compression space is in a state where a part of the lead is embedded inside the pellet after the first compression step and the second compression step. The lead is made of a conductive material. The material of the lead is not particularly limited, and examples thereof include copper, aluminum, aluminum alloys, etc. in addition to the above valve metals.

[0021] (Method of manufacturing electrolytic capacitor) The method for manufacturing an electrolytic capacitor according to the present disclosure includes a sintering step.

[0022] In the sintering step, the pellet produced by the above-mentioned pellet production method is sintered. This sintering may be performed in a vacuum. By the sintering step, an anode part of a capacitor element included in an electrolytic capacitor can be obtained.

[0023] (Production equipment for pellets for electrolytic capacitors) The manufacturing apparatus for electrolytic capacitor pellets according to the present disclosure includes a pair of first movable members, a pair of second movable members, and a control unit.

[0024] The pair of first movable members and the pair of second movable members define a compression space into which a powder containing a valve metal is filled. The pair of first movable members may face each other in a first direction. The pair of second movable members may face each other in a second direction intersecting the first direction.

[0025] The pair of first movable members are movable to expand and contract the compression space in a first direction. For example, the pair of first movable members may narrow the compression space by moving toward each other in the first direction. For example, the pair of first movable members may expand the compression space by moving away from each other in the first direction. The pair of first movable members may be moved by a first drive mechanism controlled by the control unit.

[0026] The pair of second movable members are movable to expand and contract the compression space in the second direction. For example, the pair of second movable members may narrow the compression space by moving toward each other in the second direction. For example, the pair of second movable members may expand the compression space by moving away from each other in the second direction. The pair of second movable members may be moved by a second drive mechanism controlled by the control unit.

[0027] The control unit may include a CPU and a storage device storing a program executable by the CPU. The control unit moves the pair of first movable members in a first direction so as to narrow the compression space, and then moves the pair of second movable members in a second direction so as to further narrow the compression space. The movement of the pair of first movable members narrows the compression space in the first direction, thereby compressing the powder filled in the compression space in the first direction. The subsequent movement of the pair of second movable members narrows the compression space in the second direction, thereby compressing the powder filled in the compression space in the second direction.

[0028] As described above, in the pellet manufacturing apparatus according to the present disclosure, the powder is compressed not only in one direction but also in two directions (i.e., the first direction and the second direction). Therefore, in the same manner as described in relation to the pellet manufacturing method, leakage current and short circuit defects can be suppressed in an electrolytic capacitor including pellets manufactured by the manufacturing apparatus.

[0029] Furthermore, in the pellet manufacturing apparatus according to the present disclosure, compression in the first direction is followed by compression in the second direction, which makes it possible to control the density of the powder in the pellets in the same manner as described in relation to the pellet manufacturing method.

[0030] After moving the pair of second movable members in the second direction, the control unit may move at least one of the pair of first movable members and the pair of second movable members so that the compression space is further narrowed. Here, compression in the first direction, compression in the second direction, or compression in both the first and second directions may be performed. Note that the control unit may not move the pair of first movable members and / or the pair of second movable members in this manner.

[0031] As described above, according to the present disclosure, it is possible to suppress leakage current and short circuit defects, and further, according to the present disclosure, it is possible to control the density of the powder in the pellet.

[0032] In the following, an example of the manufacturing method for electrolytic capacitor pellets, the manufacturing method for electrolytic capacitors, and the manufacturing apparatus for electrolytic capacitor pellets according to the present disclosure will be specifically described with reference to the drawings. The above-mentioned steps and components can be applied to the steps and components of the manufacturing method for electrolytic capacitor pellets, the manufacturing method for electrolytic capacitors, and the manufacturing apparatus for electrolytic capacitor pellets of the example described below. The steps and components of the manufacturing method for electrolytic capacitor pellets, the manufacturing method for electrolytic capacitors, and the manufacturing apparatus for electrolytic capacitor pellets of the example described below can be modified based on the above description. In addition, the matters described below may be applied to the above embodiment. Among the steps and components of the manufacturing method for electrolytic capacitor pellets, the manufacturing method for electrolytic capacitors, and the manufacturing apparatus for electrolytic capacitor pellets of the example described below, steps and components that are not essential for the manufacturing method for electrolytic capacitor pellets, the manufacturing method for electrolytic capacitors, and the manufacturing apparatus for electrolytic capacitor pellets according to the present disclosure may be omitted. Note that the figures shown below are schematic and do not accurately reflect the shape and number of actual members.

[0033] First Embodiment A description will be given of a first embodiment of the present disclosure. As shown in Fig. 1 and Fig. 2, a manufacturing apparatus 50 for electrolytic capacitor pellets (hereinafter also simply referred to as manufacturing apparatus 50) of this embodiment includes a base member 51, a pair of first movable members 52, a pair of second movable members 53, and a control unit 54.

[0034] The base member 51 is a somewhat thick plate-like member extending along a horizontal plane. The base member 51, together with a pair of first movable members 52 and a pair of second movable members 53, defines a compression space 55 having a substantially rectangular parallelepiped shape. The base member 51 is attached and fixed to a fixing element (not shown). The base member 51 has a rigidity sufficient to withstand the force applied when compressing the powder 41 (see FIG. 2) containing the valve metal filled in the compression space 55.

[0035] The pair of first movable members 52 and the pair of second movable members 53 are each a somewhat thick plate-like member extending along a vertical plane. The pair of first movable members 52 and the pair of second movable members 53, together with the base member 51, define a compression space 55. The pair of first movable members 52 and the pair of second movable members 53 are each movable relative to the base member 51.

[0036] The pair of first movable members 52 are movable in a first direction D1 (indicated by double-headed arrows in Figs. 1 and 2) to expand and contract the compression space 55. The pair of first movable members 52 are movable in the first direction D1 to move toward or away from each other. The pair of first movable members 52 are also movable in a second direction D2 in conjunction with the movement of the pair of second movable members 53. The pair of first movable members 52 have sufficient rigidity to withstand the force exerted when compressing the powder 41 in the compression space 55.

[0037] The pair of second movable members 53 are movable in a second direction D2 (indicated by double-headed arrows in Figs. 1 and 2) to expand and contract the compression space 55. The pair of second movable members 53 are movable in the second direction D2 to move toward or away from each other. The pair of second movable members 53 are also movable in the first direction D1 in conjunction with the movement of the pair of first movable members 52. The pair of second movable members 53 have sufficient rigidity to withstand the force exerted when compressing the powder 41 in the compression space 55.

[0038] 2, in this embodiment, the first direction D1 coincides with the width direction of the pellet 40, and the second direction D2 coincides with the thickness direction of the pellet 40. Here, the dimension of the pellet 40 in the thickness direction is smaller than the dimension of the pellet 40 in the width direction. In addition, the first direction D1 and the second direction D2 are perpendicular to each other.

[0039] The control unit 54 controls the movement of the pair of first movable members 52 and the pair of second movable members 53. Specifically, the control unit 54 moves the pair of first movable members 52 in the first direction D1 so as to narrow the compression space 55, and then moves the pair of second movable members 53 in the second direction D2 so as to further narrow the compression space 55. The control unit 54 includes a CPU and a storage device in which a program executable by the CPU is stored.

[0040] -Method of manufacturing electrolytic capacitor pellets- Next, an example of a method for manufacturing pellets for electrolytic capacitors using the above-mentioned manufacturing apparatus 50 will be described. The manufacturing method includes a filling step, a lead arrangement step, a first compression step, and a second compression step. Either the filling step or the lead arrangement step may be performed first.

[0041] In the filling step, as shown on the left side of Fig. 2, powder 41 containing a valve metal is filled into compression space 55. At this time, since compression space 55 is larger in both the thickness direction and width direction compared to the final shape of pellet 40, powder 41 can be filled more easily than in the conventional method in which compression is performed in only one direction.

[0042] In the lead placement step, as shown on the left side of FIG. 2, a portion of the lead 21b extending in the third direction D3 (indicated by a double-headed arrow in FIG. 1) is placed in the compression space 55. The third direction D3 is a direction perpendicular to the first direction D1 and the second direction D2. The lead 21b may be supported by a lid member (not shown) having an insertion hole through which the lead 21b passes. The lid member closes the upper side of the compression space 55 in the first compression step and the second compression step. The direction that coincides with the third direction D3 is the length direction of the pellet 40.

[0043] In the first compression step, as shown in the center of Fig. 2, the control unit 54 moves the pair of first movable members 52 in a first direction D1 so that they approach each other. This narrows the compression space 55 in the first direction D1, and the powder 41 in the compression space 55 is compressed in the first direction D1. At this time, since the powder 41 can move freely in the compression space 55, variations in powder density are unlikely to occur in the second direction D2 (i.e., the thickness direction of the pellet 40).

[0044] In this embodiment, all the compression required in the first direction D1 is performed in the first compression step. In other words, assuming that the moving distance of the pair of first movable members 52 required to manufacture the pellets 40 is 100, in the first compression step of this embodiment, the pair of first movable members 52 is moved in the first direction D1 by 100.

[0045] In the second compression step, as shown on the right side of Fig. 2, the control unit 54 moves the pair of second movable members 53 in the second direction D2 so that they approach each other. This narrows the compression space 55 in the second direction D2, and the powder 41 in the compression space 55 is compressed in the second direction D2. In this manner, the electrolytic capacitor pellets 40 are manufactured.

[0046] -Manufacturing method of electrolytic capacitors- Next, a description will be given of a method for manufacturing an electrolytic capacitor using the above-mentioned electrolytic capacitor pellets 40. The method for manufacturing an electrolytic capacitor includes a capacitor element preparation step, a lead terminal joining step, a sealing step, and a bending step.

[0047] In the capacitor element preparation step, a capacitor element 20 (see FIG. 3) is prepared. The capacitor element preparation step includes a sintering step, a dielectric layer forming step, a solid electrolyte layer forming step, and a cathode layer forming step.

[0048] In the sintering step, the electrolytic capacitor pellets 40 manufactured by the above-mentioned method for manufacturing electrolytic capacitor pellets are sintered. In the sintering step, the pellets 40 are sintered in a vacuum. As a result, the anode part 21 (see FIG. 3) including the anode body 21a is obtained.

[0049] In the dielectric layer forming step, dielectric layer 22 (see FIG. 3) is formed on anode body 21a. Specifically, anode body 21a is immersed in a chemical conversion tank filled with an electrolytic solution (e.g., phosphoric acid aqueous solution) and anodization is performed to form dielectric layer 22 made of an oxide film of a valve metal on the surface of anode body 21a. The electrolytic solution is not limited to phosphoric acid aqueous solution, and nitric acid, acetic acid, sulfuric acid, etc. can be used.

[0050] In the solid electrolyte layer forming step, a solid electrolyte layer 23a (see FIG. 3) is formed. In this embodiment, a solid electrolyte layer 23a containing a conductive polymer is formed. Such a solid electrolyte layer 23a is formed on at least a portion of the dielectric layer 22 by, for example, impregnating the anode body 21a on which the dielectric layer 22 is formed with a monomer or an oligomer, and then polymerizing the monomer or oligomer by chemical polymerization or electrolytic polymerization. Alternatively, the solid electrolyte layer 23a may be formed on at least a portion of the dielectric layer 22 by a method of impregnating the anode body 21a on which the dielectric layer 22 is formed with a solution or dispersion of a conductive polymer, and drying the solution or dispersion.

[0051] In the cathode layer forming step, the cathode layer 23b (see FIG. 3) is formed. In this embodiment, the cathode layer 23b is formed by a carbon layer and a metal particle layer. Such a cathode layer 23b is formed, for example, by sequentially applying a carbon paste and a metal paste to the surface of the solid electrolyte layer 23a. The configuration of the cathode layer 23b is not limited to this, and may be any configuration having a current collecting function.

[0052] In the lead terminal bonding process, the anode lead terminal 31 and the cathode lead terminal 32 (see FIG. 3 for each) are placed at predetermined positions. At this time, a conductive member 34 is applied to a predetermined position of the cathode layer 23b. Then, the capacitor element 20 is placed on the cathode lead terminal 32. Next, the lead 21b of the capacitor element 20 and the vicinity of one end of the anode lead terminal 31 are bonded by laser welding, resistance welding, or the like. At this time, the vicinity of one end of the cathode lead terminal 32 is bonded to the cathode layer 23b via the conductive member 34.

[0053] In the sealing process, capacitor element 20 and materials for exterior body 33 (see FIG. 3) (e.g., uncured thermosetting resin and filler) are placed in a mold, and capacitor element 20 is sealed by transfer molding, compression molding, or the like. At this time, anode lead terminal 31 and cathode lead terminal 32 are partially exposed from the mold. There are no particular limitations on the molding conditions, and time and temperature conditions may be set appropriately taking into consideration the curing temperature of the thermosetting resin used, etc.

[0054] In the bending process, after the capacitor element 20 covered with the exterior body 33 is removed from the mold, the portions of the anode lead terminal 31 and the cathode lead terminal 32 exposed from the mold are bent along a guide. As a result, a portion of the anode lead terminal 31 and the cathode lead terminal 32 are disposed on the mounting surface (the lower surface in FIG. 3) of the exterior body 33. In this manner, the electrolytic capacitor 10 is manufactured.

[0055] -Composition of electrolytic capacitors- The configuration of an electrolytic capacitor 10 manufactured by the above-mentioned method for manufacturing an electrolytic capacitor will be described with reference to Fig. 3. As shown in the figure, the electrolytic capacitor 10 includes a capacitor element 20, an anode lead terminal 31, a cathode lead terminal 32, and an exterior body 33.

[0056] The capacitor element 20 has an anode portion 21, a dielectric layer 22, and a cathode portion 23.

[0057] The anode part 21 includes an anode body 21a and a lead 21b. The anode body 21a is a porous sintered body having a substantially rectangular parallelepiped shape, and a dielectric layer 22 is formed on the surface of the anode body 21a. A part of the lead 21b protrudes from an end face of the anode body 21a (the left end face in FIG. 3), and the remaining part of the lead 21b is embedded in the anode body 21a.

[0058] The cathode section 23 includes a solid electrolyte layer 23a disposed so as to cover the dielectric layer 22 (anode body 21a) and a cathode layer 23b formed on the solid electrolyte layer 23a. The cathode layer 23b includes, for example, a carbon layer formed on the solid electrolyte layer 23a and a metal particle layer formed on the carbon layer. The metal particle layer is a layer formed using, for example, a metal paste.

[0059] Anode lead terminal 31 is connected to lead 21b, and a portion of it is exposed on the bottom surface of electrolytic capacitor 10. That is, anode lead terminal 31 is electrically connected to anode portion 21 of capacitor element 20. Note that the shape of anode lead terminal 31 shown in Fig. 3 is just one example, and other shapes may be used as long as it functions as anode lead terminal 31.

[0060] Cathode lead terminal 32 is connected to cathode portion 23 via conductive member 34, and a portion of cathode lead terminal 32 is exposed at the bottom surface of electrolytic capacitor 10. That is, cathode lead terminal 32 is electrically connected to cathode portion 23 of capacitor element 20. Note that the shape of cathode lead terminal 32 shown in FIG. 3 is just one example, and other shapes may be used as long as the function of cathode lead terminal 32 is fulfilled.

[0061] The exterior body 33 seals the capacitor element 20. The exterior body 33 includes, for example, a thermosetting resin and a filler. The exterior body 33 is formed in a substantially rectangular parallelepiped shape.

[0062] Second Embodiment A second embodiment of the present disclosure will be described. This embodiment differs from the first embodiment in the operation of the pair of first movable members 52 and the pair of second movable members 53. Below, the differences from the first embodiment will be mainly described.

[0063] 4, in this embodiment, the first direction D1 coincides with the thickness direction of the pellet 40, and the second direction D2 coincides with the width direction of the pellet 40. Here, the dimension of the pellet 40 in the thickness direction is smaller than the dimension of the pellet 40 in the width direction. In addition, the first direction D1 and the second direction D2 are perpendicular to each other.

[0064] The method for producing electrolytic capacitor pellets of this embodiment includes a filling step, a lead arrangement step, a first compression step, a second compression step, and a third compression step.

[0065] The filling step and the lead placement step may be performed in the same manner as in the first embodiment above.

[0066] In the first compression step, as shown in the second from the left in Fig. 4, the control unit 54 moves the pair of first movable members 52 in the first direction D1 so that they approach each other. As a result, the compression space 55 narrows in the first direction D1, and the powder 41 in the compression space 55 is compressed in the first direction D1.

[0067] In this embodiment, in the first compression step, a part of the compression required in the first direction D1 is performed. In other words, assuming that the moving distance of the pair of first movable members 52 required to manufacture the pellets 40 is 100, in the first compression step of this embodiment, the pair of first movable members 52 is moved in the first direction D1 by a distance smaller than 100 (e.g., 80).

[0068] In the second compression step, as shown in the third from the left in Fig. 4, the control unit 54 moves the pair of second movable members 53 in the second direction D2 so that they approach each other. As a result, the compression space 55 narrows in the second direction D2, and the powder 41 in the compression space 55 is compressed in the second direction D2.

[0069] In this embodiment, in the second compression step, a part of the compression required in the second direction D2 is performed. In other words, assuming that the moving distance of the pair of second movable members 53 required to manufacture the pellets 40 is 100, in the second compression step of this embodiment, the pair of second movable members 53 are moved in the second direction D2 by a distance smaller than 100 (e.g., 30).

[0070] In the third compression step, as shown in the rightmost part of Fig. 4, the control unit 54 moves the pair of first movable members 52 in a first direction D1 so that they approach each other, and moves the pair of second movable members 53 in a second direction D2 so that they approach each other. This narrows the compression space 55 in the first direction D1 and the second direction D2, and the powder 41 in the compression space 55 is compressed in the first direction D1 and the second direction D2. In this way, the electrolytic capacitor pellets 40 are manufactured. [Industrial Applicability]

[0071] The present disclosure can be used in a manufacturing method for pellets for electrolytic capacitors, a manufacturing method for electrolytic capacitors, and an apparatus for manufacturing pellets for electrolytic capacitors. [Explanation of symbols]

[0072] 10: Electrolytic capacitor 20: Capacitor element 21: Anode part 21a: Anode body 21b: Lead 22: Dielectric layer 23: Cathode 23a: Solid electrolyte layer 23b: Cathode layer 31: Anode lead terminal 32: Cathode lead terminal 33: Exterior body 34: Conductive material 40: Pellets for electrolytic capacitors 41: Powder 50: Manufacturing equipment 51: Base material 52: First movable member 53: Second movable member 54: Control unit 55: Compression space D1: 1st direction D2:Second direction D3: Third direction

Claims

1. a filling step of filling the compression space with a powder containing a valve metal; a first compression step of compressing the powder in a first direction by narrowing the compression space in the first direction; a second compression step of compressing the powder in a second direction by narrowing the compression space in a second direction intersecting the first direction after the first compression step; a third compression step in which the compression space is narrowed in the first direction and also in the second direction after the second compression step to further compress the powder; The method for producing pellets for electrolytic capacitors comprises the steps of:

2. the first direction is a width direction intersecting a thickness direction of the electrolytic capacitor pellet, The second direction is the thickness direction, 2 . The method for producing pellets for electrolytic capacitors according to claim 1 , wherein the dimension in the thickness direction of the pellets for electrolytic capacitors is equal to or smaller than the dimension in the width direction of the pellets for electrolytic capacitors.

3. the first direction is a thickness direction of the electrolytic capacitor pellet, The second direction is a width direction intersecting the thickness direction, 2 . The method for producing pellets for electrolytic capacitors according to claim 1 , wherein the dimension in the thickness direction of the pellets for electrolytic capacitors is equal to or smaller than the dimension in the width direction of the pellets for electrolytic capacitors.

4. 4. The method for producing pellets for electrolytic capacitors according to claim 1, further comprising, prior to the first compression step, a lead arrangement step of arranging a portion of a lead extending in a third direction intersecting the first direction and the second direction in the compression space.

5. A method for producing an electrolytic capacitor, comprising a sintering step of sintering electrolytic capacitor pellets produced by the method for producing electrolytic capacitor pellets according to any one of claims 1 to 4.

6. a pair of first movable members and a pair of second movable members defining a compression space into which a powder containing a valve metal is filled; The pair of first movable members are movable so as to expand and contract the compression space in a first direction, the pair of second movable members are movable so as to expand and contract the compression space in a second direction intersecting the first direction, a control unit that moves the pair of first movable members in the first direction so as to narrow the compression space, and then moves the pair of second movable members in the second direction so as to further narrow the compression space, The control unit moves the pair of second movable members in the second direction, and then moves the pair of first movable members while also moving the pair of second movable members so that the compression space is further narrowed.

7. the first direction is a width direction intersecting a thickness direction of the electrolytic capacitor pellet, The second direction is the thickness direction, 7. The apparatus for manufacturing pellets for electrolytic capacitors according to claim 6, wherein the dimension in the thickness direction of the pellets for electrolytic capacitors is equal to or smaller than the dimension in the width direction.

8. the first direction is a thickness direction of the electrolytic capacitor pellet, The second direction is a width direction intersecting the thickness direction, 7. The apparatus for manufacturing pellets for electrolytic capacitors according to claim 6, wherein the dimension in the thickness direction of the pellets for electrolytic capacitors is equal to or smaller than the dimension in the width direction.

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