JP2012059910A - Electrolytic capacitor, and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolytic capacitor having high design flexibility regarding the configuration of an anode body and an anode extraction member, and a method of manufacturing the same.SOLUTION: This method of manufacturing the electrolytic capacitor has a first process to manufacture a sintered body serving as the anode body of a capacitor element. An engagement part with which an extraction base material serving as the anode extraction member of the capacitor element is engaged is formed in the sintered body. In the first process, a molded body 60 of valve action metal which serves as the sintered body is manufactured by disposing a dummy member 61 at a spot P where the engagement part is formed, after that, the dummy member 61 is removed from the molded body 60, and the sintered body is then sintered at a first prescribed temperature to manufacture the sintered body.

Description

  The present invention relates to an electrolytic capacitor and a method for manufacturing the same, and more particularly to an electrolytic capacitor characterized in the anode portion of a capacitor element and a method for manufacturing the same.

  Among electrolytic capacitors, particularly in a solid electrolytic capacitor having a lead-type capacitor element, the capacitor element includes an anode body, an anode lead planted on the anode body, and a dielectric formed on the surface of the anode body. It is comprised from the body layer, the electrolyte layer formed on this dielectric material layer, and the cathode layer formed on the electrolyte layer above the outer peripheral surface of an anode body (for example, refer patent document 1).

  Conventionally, the anode body and the anode lead are made of the same kind of valve metal, and tantalum is used as the valve metal. Then, the anode body and the anode lead are manufactured by the method described below. That is, a powder molded body of tantalum powder to be an anode body is formed in a state where a tantalum lead base material to be an anode lead is planted thereon, and then the powder molded body and the lead base material are formed at a predetermined temperature. Bake simultaneously. Here, the predetermined temperature is a temperature for sintering the tantalum powder.

JP 2008-91784 A

  In the conventional method described above, the melting point of tantalum is about 3000 ° C., whereas the predetermined temperature (temperature for sintering the tantalum powder) is 1000 ° C. to 1500 ° C. Therefore, even when the powder molded body and the lead base material are fired simultaneously at a predetermined temperature, the lead base material made of tantalum is hardly affected by the firing of the powder molded body (for example, deformation or dissolution). It was.

  On the other hand, aluminum which is a valve action metal has higher conductivity than tantalum. Therefore, from the viewpoint of reducing ESR (equivalent series resistance) of the electrolytic capacitor, it is preferable to use aluminum as a constituent material of the anode lead. On the other hand, tantalum oxide serving as a dielectric has a higher dielectric constant than aluminum oxide. For this reason, from the viewpoint of increasing the capacitance of the electrolytic capacitor, it is preferable to use tantalum as a constituent material of the anode body.

  When an anode body composed of tantalum and an anode lead composed of aluminum are produced using the above-described conventional method, a powdered tantalum powder molded body and an aluminum lead substrate are made of tantalum powder. It is fired simultaneously at a predetermined temperature (1000 ° C. to 1500 ° C.) for sintering. However, since the melting point (about 660 ° C.) of aluminum is significantly lower than the predetermined temperature, the lead base material is deformed or melted by firing. Therefore, conventionally, it has been difficult to employ different types of valve metals for the constituent material of the anode body and the anode lead, and therefore, the degree of freedom in designing the combination of constituent materials of the anode body and the anode lead has been low.

  Further, in the conventional method described above, the powder molded body is produced by molding a valve metal powder using a mold, and at this time, a part of the lead base material is inserted into the mold. . For this reason, in the above electrolytic capacitor, in place of the anode lead, it is possible to apply the above-described conventional method as it is for the production of the electrolytic capacitor even when it is desired to employ an anode lead member having a different shape. In the past, the degree of freedom in design related to the shapes of the anode body and the anode lead member was low.

  Accordingly, an object of the present invention is to provide an electrolytic capacitor having a high degree of design freedom regarding the configuration of the anode body and the anode lead member, and a method for manufacturing the same.

  The method for manufacturing an electrolytic capacitor according to the present invention includes a first step. Here, the electrolytic capacitor produced by the manufacturing method includes an electrolytic capacitor element, and the capacitor element is formed on the surface of the anode body, the anode lead member provided on the anode body, and the anode body. A dielectric layer formed on the dielectric layer; an electrolyte layer formed on the dielectric layer; and a cathode layer formed on the electrolyte layer. In addition, the first step is a step of producing a sintered body that becomes the anode body, and the sintered body is formed with a fitting portion into which a drawing base material that becomes the anode drawing member is fitted. Has been. In the first step, a molded body of the valve action metal powder to be the sintered body is prepared by arranging a dummy member at a place where the fitting portion is formed, and then the dummy body is formed from the molded body. The member is removed, and then the molded body is fired at a first predetermined temperature to produce the sintered body.

  In the manufacturing method described above, the sintered body that becomes the anode body is produced separately from the extraction base material that becomes the anode extraction member. That is, it is not necessary to fire the molded body and the drawn base material at the first predetermined temperature at the same time. Therefore, even when different types of materials are used for the valve metal powder constituting the molded body and the valve metal constituting the drawer base material, the drawer base material has an influence (for example, deformation or No dissolution etc.) Moreover, the said manufacturing method is applicable when producing the anode body and anode drawer member which have various shapes. Therefore, according to the said manufacturing method, the design freedom regarding the structure (a combination of a structural material, a shape, etc.) of an anode body and an anode drawer member improves.

  In a specific aspect of the manufacturing method, the manufacturing method further includes a second step. After execution of the first step, in the second step, the drawn base material is fitted to the fitting portion of the sintered body, and then the sintered body and the drawn base material are lower than the first predetermined temperature. Baking at a second predetermined temperature.

  According to the specific embodiment, the sintered body and the drawn base material can be sintered together with little influence on the structure and electrical characteristics of the sintered body.

  In a more specific aspect, a material having a melting point lower than the first predetermined temperature is used for the valve action metal constituting the drawer base material, and the second predetermined temperature is a valve constituting the drawer base material. It is set to a temperature below the melting point of the working metal and in the vicinity of the melting point.

  According to the specific embodiment, when the sintered body and the drawn base material are fired at the second firing temperature, the surface of the drawn base material is dissolved and the drawn base material is welded to the inner wall surface of the fitting portion. As a result, the sintered body and the drawn base material are sintered together. Therefore, the sintered body and the drawn base material have good electrical and mechanical joining states.

  In another more specific aspect, different materials are used for the valve metal powder constituting the molded body and the valve metal constituting the drawer base material, and the oxide of the constituent material of the molded body is The dielectric constant is higher than the oxide of the constituent material of the drawer base material, and the constituent material of the drawer base material has higher conductivity than the constituent material of the molded body.

  According to the specific aspect, an electrolytic capacitor having a large capacitance and a small ESR (equivalent series resistance) can be produced. For example, tantalum powder having a first firing temperature of 1000 ° C. to 1500 ° C. is used as the valve metal powder constituting the molded body, and aluminum having a melting point of about 660 ° C. is used as the valve metal constituting the drawer base. Can be used. Here, tantalum oxide (tantalum oxide) has a higher dielectric constant than aluminum oxide (aluminum oxide), while aluminum has a higher conductivity than tantalum.

  An electrolytic capacitor according to the present invention comprises an electrolytic capacitor element, the capacitor element comprising an anode body made of a porous sintered body, an anode lead member provided on the anode body, and an outer peripheral surface of the anode body. And a dielectric layer formed on the inner wall surface of a plurality of holes existing in the anode body, an electrolyte layer formed on the dielectric layer, and an electrolyte layer formed above the outer peripheral surface of the anode body. Cathode layer. Here, the porous sintered body constituting the anode body is a sintered body formed by firing a molded body of the valve action metal powder, and the valve action metal powders are partially sintered. In the sintered body, a fine gap is formed, and at the interface between the anode body and the anode lead member, a part of the anode lead member is in the fine gap existing in the anode body. Is invading.

  The electrolytic capacitor is manufactured by carrying out the manufacturing method according to the present invention.

  In the specific configuration of the electrolytic capacitor, different types of materials are used for the valve action metal constituting the anode body and the anode lead member, and the oxide of the constituent material of the anode body is the oxidation of the constituent material of the anode lead member. The dielectric constant is higher than that of the object, and the constituent material of the anode lead member has higher conductivity than the constituent material of the anode body.

  The electrolytic capacitor and the manufacturing method thereof according to the present invention have a high degree of design freedom regarding the configuration of the anode body and the anode lead member.

FIG. 1 is a cross-sectional view of a solid electrolytic capacitor according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing a region near the interface between the anode body and the anode lead for the capacitor element provided in the solid electrolytic capacitor. FIG. 3 is an enlarged cross-sectional view of the capacitor element in the vicinity of the outer peripheral surface of the anode body. FIG. 4 is a perspective view used for explaining the first stage of the first step of the anode manufacturing step of the device manufacturing step in the method of manufacturing the solid electrolytic capacitor. FIG. 5 is a perspective view used for explaining the middle step of the first step in the anode manufacturing step. FIG. 6 is a perspective view used for explaining the latter stage of the first step in the anode manufacturing step. FIG. 7 is an enlarged cross-sectional view showing a region in the vicinity of the inner wall surface of the fitting portion of the porous sintered body produced in the anode production step. FIG. 8 is a cross-sectional view showing an enlarged region in the vicinity of the outer peripheral surface of the porous sintered body produced in the anode production step. FIG. 9 is a perspective view used for explaining the former stage of the second step in the anode manufacturing step. FIG. 10 is a perspective view showing the state of the porous sintered body and the lead base material after execution of the first stage of the second step. FIG. 11 is an enlarged cross-sectional view showing a region in the vicinity of the interface of the porous sintered body and the lead base material after execution of the second stage of the second step. FIG. 12 is a cross-sectional view showing an enlarged region in the vicinity of the interface of the porous sintered body and the lead base material after the second stage of the second step. FIG. 13 is a diagram used for explaining the dielectric layer forming step in the element manufacturing step. FIG. 14 is a cross-sectional view showing an enlarged region in the vicinity of the outer peripheral surface of the porous sintered body after execution of the dielectric layer forming step. FIG. 15 is a cross-sectional view showing an enlarged region in the vicinity of the interface of the porous sintered body and the lead base material after the dielectric layer forming step is performed. FIG. 16 is a diagram used for explaining the electrolyte layer forming step in the element manufacturing step. FIG. 17 is an enlarged cross-sectional view of the vicinity of the outer peripheral surface of the anode body after the electrolyte layer forming step. FIG. 18 is a side view used for explaining the element mounting step in the manufacturing method. FIG. 19 is an enlarged cross-sectional view showing a region in the vicinity of the interface between the anode body and the anode lead for a capacitor element provided in a conventional solid electrolytic capacitor. FIG. 20 is a perspective view showing a porous sintered body and a drawn base material produced in the manufacturing process of the solid electrolytic capacitor in the first modification of the solid electrolytic capacitor. FIG. 21 is a perspective view showing a porous sintered body and a drawn base material produced in the manufacturing process of the solid electrolytic capacitor in the second modification of the solid electrolytic capacitor. FIG. 22: is a perspective view used for description of the front | former stage of the 1st process about the anode preparation process of an element preparation process among the manufacturing methods of the solid electrolytic capacitor which concerns on a 2nd modification. FIG. 23 is a perspective view used for explaining the middle stage of the first step in the anode manufacturing step. FIG. 24 is a perspective view used for explaining the latter stage of the first step in the anode manufacturing step. FIG. 25 is a perspective view used for explaining the former stage of the second step in the anode manufacturing step.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a solid electrolytic capacitor and an embodiment in which the present invention is manufactured will be specifically described with reference to the drawings.
FIG. 1 is a cross-sectional view of a solid electrolytic capacitor according to an embodiment of the present invention. As shown in FIG. 1, the solid electrolytic capacitor includes a solid electrolytic capacitor element (1), an exterior member (2) covering the capacitor element (1), an anode terminal (3), and a cathode terminal ( 4). The exterior member (2) is formed from a resin such as an epoxy resin.

  The capacitor element (1) includes an anode body (11) made of a porous sintered body and an anode lead (12) planted on the anode body (11). Here, the outer peripheral surface of the anode body (11) includes a first surface (11a) from which the anode lead (12) is drawn, a second surface (11b) opposite to the first surface (11a), The side surface (11c) extends from the outer peripheral edge of the first surface (11a) to the outer peripheral edge of the second surface (11b).

  The anode body (11) and the anode lead (12) are both made of a valve metal, and the anode body (11) and the anode lead (12) are electrically connected to each other. Here, different types of materials are used for the valve action metals constituting the anode body (11) and the anode lead (12), respectively. In the present embodiment, tantalum is used as the constituent material of the anode body (11), and aluminum is used as the constituent material of the anode lead (12). Therefore, the oxide of the constituent material of the anode body (11) has a higher dielectric constant than the oxide of the constituent material of the anode lead (12), and the constituent material of the anode lead (12) is the anode body (11). The conductivity is higher than that of the constituent material.

  FIG. 2 is an enlarged cross-sectional view of the capacitor element (1) in the vicinity of the interface (11d) between the anode body (11) and the anode lead (12). The anode body (11) is a sintered body formed by firing a powder molded body of valve action metal powder, and as shown in FIG. On the other hand, fine gaps are formed in the sintered body, and a plurality of holes (110) are formed by the fine gaps. Then, at the interface (11d) between the anode body (11) and the anode lead (12), a part of the anode lead (12) penetrates into the plurality of holes (110) existing in the anode body (11). Yes.

  FIG. 3 is an enlarged cross-sectional view of the capacitor element (1) in the vicinity of the outer peripheral surface of the anode body (11). As shown in FIG. 3 (see also FIGS. 1 and 2), the capacitor element (1) further includes a plurality of holes (110) on the outer peripheral surface of the anode body (11) and in the anode body (11). The dielectric layer (13) formed on the inner wall surface, the electrolyte layer (14) formed on the dielectric layer (13), and the outer peripheral surface of the anode body (11) (specifically, the second layer) A cathode layer (15) formed on the electrolyte layer (14) above the surface (11b) and the side surface (11c)). In FIG. 1, only a part of the dielectric layer (13) and the electrolyte layer (14) formed on the outer peripheral surface of the anode body (11) is shown.

  Here, the dielectric layer (13) is composed of an oxide film formed on the outer peripheral surface of the anode body (11) and on the inner wall surfaces of the plurality of holes (110) existing in the anode body (11). Yes. The electrolyte layer (14) is formed using an electrolyte material that can be solidified on the dielectric layer (13), for example, a conductive organic material such as a conductive polymer. The cathode layer (15) includes a carbon layer (not shown) formed on the electrolyte layer (14) above the outer peripheral surface of the anode body (11), and a silver paste layer ( (Not shown). The electrolyte layer (14) and the cathode layer (15) are electrically connected to each other.

  As shown in FIG. 1, the anode terminal (3) and the cathode terminal (4) are embedded in the exterior member (2). Then, by exposing a part of the surface of the anode terminal (3) to the lower surface (2a) of the exterior member (2), the anode terminal surface (30) is formed on the lower surface (2a) of the exterior member (2). On the other hand, the cathode terminal surface (40) is formed on the lower surface (2a) of the exterior member (2) by exposing a part of the surface of the cathode terminal (4) to the lower surface (2a) of the exterior member (2). The anode terminal surface (30) is spaced from the cathode terminal surface (40) in a predetermined direction (91).

  On the anode terminal (3) and the cathode terminal (4), the capacitor element (1) is mounted with the lead portion (121) of the anode lead (12) oriented in a predetermined direction (91). The lead part (121) and the anode terminal (3) of (12) are electrically connected to each other via a conductive pillow member (31), while the cathode layer (15) and the cathode terminal (4) Are electrically connected to each other by interposing a conductive adhesive (41) between these opposing surfaces.

  Next, the manufacturing method of the said solid electrolytic capacitor is concretely demonstrated along drawing. In the manufacturing method, an element manufacturing process, an element mounting process, and an exterior forming process are sequentially performed.

  The element manufacturing process is a process of manufacturing the capacitor element (1). In the element manufacturing process, an anode manufacturing process, a dielectric layer forming process, an electrolyte layer forming process, and a cathode layer forming process are sequentially performed. The

In the anode manufacturing process, the first process and the second process are sequentially performed.
4, 5, and 6 are perspective views used for explaining the first, middle, and subsequent stages of the first step of the anode manufacturing process. This first step is a step of producing a porous sintered body (50) (see FIG. 6) to be the anode body (11). The porous sintered body (50) includes an anode lead (12). A fitting portion (502) to be fitted with the lead base material (51) (see FIG. 9) is formed. In the present embodiment, the fitting portion (502) has a round hole shape. Hereinafter, the first step will be specifically described.

  As shown in FIG. 4, in the first stage of the first step, a place P where the powdered molded body (60) of the valve action metal powder that becomes the porous sintered body (50) forms the fitting portion (502) is formed. A cylindrical dummy member (61) is arranged on the substrate. Specifically, the valve action metal powder is filled in a mold (not shown), a part of the dummy member (61) is inserted into the mold, and then the pressure is applied to the mold. Press and harden the working metal powder. Thus, the powder molded body (60) is formed in a state where the dummy member (61) is planted thereon. In the present embodiment, tantalum powder is used as a constituent material of the powder molded body (60).

  Next, as shown in FIG. 5, in the middle stage of the first step, the dummy member (61) is extracted from the powder molded body (60). As a result, in the powder molded body (60), a bottomed recess (601) having a round hole shape is formed at the place P where the dummy member (61) has been planted.

  Subsequently, as shown in FIG. 6, the powder molded body (60) is fired at the first predetermined temperature T1 in the latter stage of the first step. Here, the first predetermined temperature T1 is fine in the sintered body produced by firing, while the valve action metal powders constituting the powder molded body (60) are sintered and partially bonded. The temperature is set so that a gap is formed. In the present embodiment, the first predetermined temperature T1 is set to 1000 ° C to 1500 ° C.

  By performing the latter stage of the first step, the powder molded body (60) is sintered to form the porous sintered body (50). Then, a fitting portion (502) is formed from the bottomed recess (601) of the powder molded body (60), and the valve action is applied to the inner wall surface (502a) of the fitting portion (502) as shown in FIG. Sintered particles formed when the metal powder is sintered are exposed. Further, as shown in FIGS. 7 and 8, a fine gap is formed in the porous sintered body (50), and a plurality of holes (501) are formed by the fine gap. The outer peripheral surface of the porous sintered body (50) includes a first surface (50a) on which a fitting portion (502) is formed, and a second surface (50b) opposite to the first surface (50a). ) And a side surface (50c) extending from the outer peripheral edge of the first surface (50a) to the outer peripheral edge of the second surface (50b).

  Here, by firing the powder molded body (60), the powder molded body (60) contracts as shown in FIG. For this reason, the inner dimension W2 of the fitting part (502) of the produced porous sintered body (50) is larger than the inner dimension W1 of the bottomed recess (601) of the powder molded body (60) (see FIG. 5). Becomes smaller. Therefore, the inner dimension W1 of the bottomed recess (601) of the powder molded body (60), that is, the outer dimension W3 of the dummy member (61) (specifically, the bottomed recess (601) of the dummy member (61)). The outer dimension of the portion to be embedded in the powder molded body (60) to form the inner diameter W2 of the fitting portion (502) of the porous sintered body (50) to be produced is a predetermined dimension. As such, it is set in consideration of the amount of shrinkage of the powder molded body (60).

  FIG. 9 is a perspective view used for explanation of the former stage of the second step of the anode manufacturing step. As shown in FIG. 9, in the first stage of the second step, the lead base material (51) is inserted into the fitting portion (502) of the porous sintered body (50), thereby the lead base material as shown in FIG. (51) is fitted into the fitting portion (502). Accordingly, as shown in FIG. 11, the inner wall surface (502a) of the fitting portion (502) at the interface (50d) between the porous sintered body (50) and the lead base material (51) (see FIG. 7). The sintered particles exposed to the lead and the side surface (51a) of the lead base material (51) come into contact with each other.

  Here, the constituent material of the lead base material (51) includes a different kind of valve action metal from the constituent material of the powder molded body (60), specifically, the conductivity than the constituent material of the powder molded body (60). High valve action metals are used. In the present embodiment, aluminum having higher conductivity than tantalum, which is a constituent material of the powder molded body (60), is used as a constituent material of the lead base material (51). In addition, melting | fusing point of aluminum is about 660 degreeC, and is lower than 1st predetermined temperature T1 (1000 degreeC-1500 degreeC).

  Thereafter, in a subsequent stage of the second step, the porous sintered body (50) and the lead base material (51) are fired at a second predetermined temperature T2 lower than the first predetermined temperature T1. Here, the second predetermined temperature T2 is set to a temperature below and in the vicinity of the melting point of the valve metal (aluminum in this embodiment) constituting the lead base material (51).

  By executing the second stage of the second step, the surface of the lead base material (51) (including the side surface (51a)) is melted. As a result, as shown in FIG. At the interface (50d) with the material (51), a part of the lead base material (51) enters into the plurality of holes (501) existing in the porous sintered body (50). As a result, the lead base material (51) is welded to the inner wall surface (502a) of the fitting portion (502), whereby the porous sintered body (50) and the lead base material (51) are sintered together. become. Therefore, the porous sintered body (50) and the lead base material (51) have a good electrical and mechanical joining state.

  The second predetermined temperature T2 is set to a temperature lower than the first predetermined temperature T1. Therefore, in the second step of the anode preparation process, the porous sintered body (50) and the lead base material (51) are made to have almost no influence on the structure and electrical characteristics of the porous sintered body (50). They can be sintered together. Here, as the temperature difference between the first predetermined temperature T1 and the second predetermined temperature T2 is larger, the influence of the porous sintered body (50) upon firing in the second step becomes smaller. Therefore, as in this embodiment, tantalum powder having a first predetermined temperature T1 of 1000 ° C. to 1500 ° C. is used as a constituent material of the powder molded body (60), and a melting point is used as a constituent material of the lead substrate (51). The use of aluminum at about 660 ° C. is preferable in that the temperature difference between the first predetermined temperature T1 and the second predetermined temperature T2 becomes large.

  FIG. 13 is a diagram used for explaining the dielectric layer forming step. As shown in FIG. 13, in the dielectric layer forming step, a treatment tank (71) filled with an electrolytic solution (701) such as phosphoric acid aqueous solution or adipic acid aqueous solution is prepared. Here, a cathode plate (710) is provided in the electrolytic solution (701). Thereafter, the porous sintered body (50) is immersed in the electrolytic solution (701). As a result, the electrolytic solution (701) penetrates into the plurality of holes (501) existing in the porous sintered body (50).

  Then, as shown in FIG. 13, by applying a voltage V1 between the lead base material (51) and the cathode plate (710) and passing an electric current through the porous sintered body (50), porous sintering is performed. The outer peripheral surface of the body (50) and the inner wall surface of the hole (501) are electrochemically oxidized (anodized). Accordingly, as shown in FIGS. 14 and 15, the dielectric layer (13) is formed on the outer peripheral surface (including the side surface (11c)) of the porous sintered body (50) and on the inner wall surface of the hole (501). An oxide film is formed. Thus, in the porous sintered body (50), the anode body (11) is formed by the metal portion remaining without being oxidized, and a plurality of pores are formed by the fine gaps existing in the anode body (11). (110) will be formed. Further, the anode lead (12) is formed by the lead substrate (51).

  Next, in the electrolyte layer forming step, a precoat layer (not shown) having conductivity is formed on the dielectric layer (13). Here, the precoat layer is formed from a conductive material such as a conductive polymer using a chemical polymerization method.

  In the electrolyte layer forming step, as shown in FIG. 16, a treatment tank (72) filled with an electrolytic polymerization solution (702) made of a conductive organic material such as a conductive polymer is prepared. Here, a cathode plate (720) is provided in the electrolytic polymerization solution (702). Thereafter, the anode body (11) is immersed in the electrolytic polymerization solution (702). As a result, the electrolytic polymerization solution (702) penetrates into the plurality of holes (110) (see FIGS. 14 and 15) existing in the anode body (11).

  Then, as shown in FIG. 16, the external electrode (62) is brought into electrical contact with the precoat layer in the electrolytic polymerization solution (702), and between the external electrode (62) and the cathode plate (720). By applying the voltage V2, a constant current is passed through the precoat layer. As a result, an electrolytic polymer film is formed on the precoat layer. As a result, as shown in FIGS. 2 and 17, an electrolyte layer composed of the precoat layer and the electrolytic polymer film is formed on the dielectric layer (13). (14) is formed.

  In the cathode layer forming step, first, the anode body (11) is immersed in a carbon paste so as to be above the outer peripheral surface (specifically, the second surface (11b) and the side surface (11c)) of the anode body (11). Thus, a carbon layer is formed on the electrolyte layer (14). Thereafter, the anode body (11) is immersed in a silver paste to form a silver paste layer on the carbon layer. Thereby, as shown in FIG. 3, a cathode layer (15) is formed on the electrolyte layer (14) above the outer peripheral surface of the anode body (11). As a result, the capacitor element (1) is completed.

  FIG. 18 is a side view used for explaining the element mounting process. As shown in FIG. 18, in the element mounting step, the capacitor element (1) is mounted on the anode terminal (3) and the cathode terminal (4). Specifically, a pillow member (31) is provided on the anode terminal (3), and the anode terminal (3) is arranged at a position spaced from the cathode terminal (4) in a predetermined direction (91). Yes. In the element mounting step, the capacitor element (1) is placed on the anode terminal (3) and the cathode terminal (4) with the lead portion (121) of the anode lead (12) oriented in a predetermined direction (91). Thus, the drawer portion (121) is brought into contact with the distal end surface of the pillow member (31). At this time, a conductive adhesive (41) is interposed between the cathode layer (15) and the cathode terminal (4) of the capacitor element (1). Thereafter, welding is performed on the contact surface between the lead portion (121) of the anode lead (12) and the pillow member (31), thereby electrically joining the lead portion (121) and the pillow member (31) to each other. .

  In the exterior forming process, the capacitor element (1) is covered with the exterior member (2) as shown in FIG. 1 by using a molding technique. At this time, a part of the surface of the anode terminal (3) is exposed to the lower surface (2a) of the exterior member (2), and a part of the surface of the cathode terminal (4) is exposed to the lower surface (2a of the exterior member (2). ) To expose. Thereby, a solid electrolytic capacitor is completed.

  In the above manufacturing method, the porous sintered body (50) serving as the anode body (11) is produced separately from the lead substrate (51) serving as the anode lead (12). That is, it is not necessary to simultaneously fire the powder molded body (60) and the lead base material (51) at the first predetermined temperature T1. Therefore, as in this embodiment, even when different materials are used for the valve metal powder constituting the powder molded body (60) and the valve metal constituting the lead base material (51), the lead base material ( 51) does not receive the influence (for example, deformation, dissolution, etc.) at the time of baking of the powder molded body (60). Further, as will be described later, the above manufacturing method can also be applied to the production of a solid electrolytic capacitor in which anode lead members having various shapes are employed instead of the anode lead (12). Therefore, according to the manufacturing method described above, the degree of freedom in design regarding the configuration (combination of materials, shape, etc.) of the anode body (11) and the anode lead member (including the anode lead (12)) is improved.

  Further, in the above manufacturing method, different materials are used for the valve action metal powder constituting the powder molded body (60) and the valve action metal constituting the lead base material (51), and the powder molded body (60) The oxide of the constituent material (tantalum powder) has a higher dielectric constant than the oxide of the constituent material (aluminum) of the lead base material (51), and the constituent material (aluminum) of the lead base material (51) is The conductivity is higher than that of the constituent material (tantalum powder) of the powder molded body (60). Therefore, according to the manufacturing method, an electrolytic capacitor having a large capacitance and a small ESR (equivalent series resistance) can be produced. Further, as in the present embodiment, by using aluminum as the constituent material of the lead base material (51) (anode lead (12)), the manufacturing cost can be reduced.

  In the solid electrolytic capacitor manufactured by the above manufacturing method, as shown in FIG. 2, at the interface (11d) between the anode body (11) and the anode lead (12), a part of the anode lead (12) is an anode. It penetrates into a plurality of holes (110) existing in the body (11). In contrast, in a conventional solid electrolytic capacitor in which the anode body (11) and the anode lead (12) are both composed of tantalum, a tantalum powder powder molded body is implanted in the manufacturing process. The lead substrate made of tantalum is simultaneously fired at a temperature (1000 ° C. to 1500 ° C.) for sintering the tantalum powder. Here, the melting point of tantalum is about 3000 ° C. Therefore, the lead substrate made of tantalum does not melt during firing. Therefore, in the conventional electrolytic capacitor, as shown in FIG. 19, the anode lead (12) is not deformed at the interface (11d) between the anode body (11) and the anode lead (12). Part of the sintered particles (sintered tantalum powder) constituting the anode body (11) is welded to the side surface (12a) of the anode lead (12). Thus, the structure in the vicinity of the interface (11d) between the anode body (11) and the anode lead (12) is greatly different between the solid electrolytic capacitor according to the present embodiment and the conventional solid electrolytic capacitor.

  FIG. 20 is a perspective view showing a porous sintered body (50) and a drawn substrate (52) produced in the manufacturing process of the solid electrolytic capacitor in the first variation of the solid electrolytic capacitor. As shown in FIG. 20, in the second step (FIG. 9) of the anode preparation step described above, the fitting portion (502) of the porous sintered body (50) is replaced with the lead base material (51), A drawer base material (52) having a shape different from this may be fitted. Here, the drawn base material (52) is provided so as to project from the flat plate portion (521) that comes into surface contact with the first surface (50a) of the porous sintered body (50), and the flat plate portion (521). And a lead portion (522) to be fitted into the fitting portion (502) of the porous sintered body (50).

  FIG. 21 is a perspective view showing a porous sintered body (50) and a drawn substrate (52) produced in the manufacturing process of the solid electrolytic capacitor in the second modification of the solid electrolytic capacitor. As shown in FIG. 21, the drawn base material (52) has a rectangular parallelepiped shape, and most of the portion is embedded in the porous sintered body (50). Specifically, a part of the drawn base material (52) slightly protrudes from the side surface (50c) of the porous sintered body (50), and a part of the surface of the drawn base material (52) The porous sintered body (50) is exposed on the first surface (50a) and is aligned on the same plane as the first surface (50a).

Next, of the method for manufacturing a solid electrolytic capacitor according to the second modification, the anode manufacturing process of the element manufacturing process will be specifically described.
22, FIG. 23, and FIG. 24 are perspective views used for explaining the first, middle, and subsequent stages of the first step of the anode manufacturing process. This first step is a step of producing a porous sintered body (50) (see FIG. 24) to be the anode body (11). The porous sintered body (50) includes a drawn substrate (52). ) (See FIG. 25) is formed with a fitting portion (502). In this modification, the fitting part (502) has a hollow shape. Hereinafter, the first step will be specifically described.

  As shown in FIG. 22, in the first stage of the first step, the molded product (60) of valve action metal powder (tantalum powder) that becomes the porous sintered body (50) is not formed into the fitting part (502). A prismatic dummy member (63) is arranged at a place P to be manufactured. Specifically, the valve action metal powder is filled in a mold (not shown), a part of the dummy member (63) is inserted into the mold, and then the pressure is applied to the mold. Press and harden the working metal powder. As a result, the powder molded body (60) is formed with the dummy member (63) planted thereon.

  Next, as shown in FIG. 23, the dummy member (63) is extracted from the powder molded body (60) in the middle stage of the first step. As a result, in the powder molded body (60), a recessed bottomed recess (602) is formed at a location P where the dummy member (63) has been planted. Subsequently, as shown in FIG. 24, in the latter stage of the first step, the powder molded body (60) is fired at a first predetermined temperature T1 (1000 ° C. to 1500 ° C.). As a result, the powder molded body (60) is sintered to form the porous sintered body (50). And a fitting part (502) will be formed from the bottomed recessed part (602) of a powder molding (60).

  Here, by firing the powder molded body (60), the powder molded body (60) contracts as shown in FIG. For this reason, the inner dimension W2 of the fitting part (502) of the produced porous sintered body (50) is larger than the inner dimension W1 of the bottomed recess (602) of the powder molded body (60) (see FIG. 23). Becomes smaller. Accordingly, the inner dimension W1 of the bottomed recess (602) of the powder molded body (60), that is, the outer dimension W3 of the dummy member (63) (specifically, the bottomed recess (602) of the dummy member (63)). The outer dimension of the portion to be embedded in the powder molded body (60) to form the inner diameter W2 of the fitting portion (502) of the porous sintered body (50) to be produced is a predetermined dimension. As such, it is set in consideration of the amount of shrinkage of the powder molded body (60).

  FIG. 25 is a perspective view used for explanation of the former stage of the second step of the anode manufacturing step. As shown in FIG. 25, in the first stage of the second step, the drawn base material (52) is inserted into the fitting portion (502) of the porous sintered body (50), so that the drawn base material as shown in FIG. (52) is fitted to the fitting portion (502). Thereafter, in a subsequent stage in the second step, the porous sintered body (50) and the drawn base material (52) are fired at a second predetermined temperature T2 (temperature near the melting point of aluminum) lower than the first predetermined temperature T1. . As a result, the porous sintered body (50) and the drawn base material (52) are sintered together.

  In addition, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim. For example, niobium may be adopted as a constituent material of the anode body (11). Further, the combination of the constituent materials of the anode body (11) and the anode lead member (including the anode lead (12)) is not limited to the above-mentioned combination of tantalum and aluminum, but valve action of tantalum, niobium, titanium, aluminum, etc. Various combinations selected from metals can be employed. However, a valve action metal having a melting point lower than the first predetermined temperature T1 set according to the constituent material of the anode body (11) is selected as the constituent material of the anode lead member (including the anode lead (12)). There is a need.

  Further, the shapes of the porous sintered body (50) and the drawn base material (52) (including the lead base material (51)) shown in FIGS. 10, 20, and 21 are examples, and various modifications are possible. Is possible. Furthermore, the various configurations employed in the solid electrolytic capacitor and the manufacturing method thereof are not limited to the solid electrolytic capacitor shown in FIG. 1 and its production, and can be applied to various electrolytic capacitors and their production.

(1) Capacitor element
(11) Anode body
(11d) Interface
(110) Hole
(12) Anode lead (anode lead member)
(12a) Side view
(121) Drawer
(13) Dielectric layer
(14) Electrolyte layer
(15) Cathode layer
(2) Exterior material
(2a) Bottom surface
(3) Anode terminal
(30) Anode terminal surface
(31) Pillow member
(4) Cathode terminal
(40) Cathode terminal surface
(41) Conductive adhesive
(50) Porous sintered body
(50d) Interface
(501) Hole
(502) Mating part
(502a) Inner wall
(51) Lead substrate (drawer substrate)
(51a) Side view
(52) Drawer base material
(521) Flat plate
(522) Lead
(60) Powder molding
(601) Bottomed recess
(602) Bottomed recess
(61) Dummy member
(62) External electrode
(63) Dummy member T1 First predetermined temperature T2 Second predetermined temperature

Claims (6)

An electrolytic capacitor element is provided, and the capacitor element is formed on the dielectric layer, an anode lead member provided on the anode body, a dielectric layer formed on the surface of the anode body, and the dielectric layer. A method for producing an electrolytic capacitor comprising an electrolyte layer formed and a cathode layer formed on the electrolyte layer,
A first step of producing a sintered body to be the anode body, and the sintered body is formed with a fitting portion into which a drawing base material to be the anode drawing member is fitted; In the first step, a molded body of valve action metal powder to be the sintered body is prepared by arranging a dummy member at a position where the fitting portion is formed, and then the dummy member is formed from the molded body. A method for manufacturing an electrolytic capacitor, wherein the sintered body is produced by removing the sintered body and subsequently firing the molded body at a first predetermined temperature.   After the execution of the first step, the drawn base material is fitted to the fitting portion of the sintered body, and then the sintered body and the drawn base material are set at a second predetermined temperature lower than the first predetermined temperature. The manufacturing method of the electrolytic capacitor which further has the 2nd process of baking.   A material having a melting point lower than the first predetermined temperature is used for the valve action metal constituting the drawer base, and the second predetermined temperature is lower than the melting point and the melting point of the valve action metal constituting the drawer base. The method for manufacturing an electrolytic capacitor according to claim 2, wherein the electrolytic capacitor is set to a temperature in the vicinity.   Different materials are used for the valve metal powder constituting the molded body and the valve metal constituting the drawer base material, and the oxide of the constituent material of the molded body is oxidized of the constituent material of the drawer base material. 4. The method for manufacturing an electrolytic capacitor according to claim 2, wherein the dielectric constant is higher than that of the product, and the constituent material of the drawn base material has higher conductivity than the constituent material of the molded body. An electrolytic capacitor element is provided, and the capacitor element includes an anode body made of a porous sintered body, an anode lead member provided on the anode body, and a plurality of existing on the outer peripheral surface of the anode body and in the anode body. The dielectric layer is formed on the inner wall surface of the hole, the electrolyte layer is formed on the dielectric layer, and the cathode layer is formed on the electrolyte layer above the outer peripheral surface of the anode body. In the electrolytic capacitor
The porous sintered body constituting the anode body is a sintered body formed by firing a molded body of valve action metal powder, and the valve action metal powders are sintered and partially bonded. On the other hand, a fine gap is formed in the sintered body, and at the interface between the anode body and the anode lead member, a part of the anode lead member penetrates into the fine gap existing in the anode body. Electrolytic capacitor characterized by   Different materials are used for the valve metal constituting the anode body and the anode lead member, and the oxide of the constituent material of the anode body has a higher dielectric constant than the oxide of the constituent material of the anode lead member. The electrolytic capacitor according to claim 5, wherein the constituent material of the anode lead member has higher conductivity than the constituent material of the anode body.

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