JP4911590B2 - Solid electrolytic capacitor and manufacturing method thereof - Google Patents

Description

The present invention relates to a solid electrolytic capacitor having a lead frame and a method for manufacturing the same .

  Conventionally, a structure as shown in FIG. 3 is known as a solid electrolytic capacitor (1). (See Patent Document 1) The solid electrolytic capacitor shown in this figure is an anode planted from one end face of an anode body (31) made of a valve metal (tantalum, niobium, aluminum, etc.) as shown in detail in FIG. Conductive inorganic material having a thin wire-like anode lead (2) made of the same valve metal as the body (31), a dielectric oxide film (32), manganese dioxide, etc. on the peripheral surface of the anode body (31) Alternatively, a solid electrolyte layer (33) made of a conductive organic material such as TCNQ complex salt or a conductive polymer, and a cathode lead layer (34) made of conductive carbon, silver, etc. are sequentially formed to constitute a capacitor element (3). The cathode lead frame (42) is connected to the peripheral surface of the capacitor element (3) by a conductive adhesive (5), and the anode lead frame (41) is connected to the tip (22) of the anode lead (2) by resistance welding or the like. ), And then the capacitor element (3), anode lead (2), anode lead frame (41) with exterior resin (6) And a part of the cathode lead frame (42) is housed, and the lead frames (41) (42) protruding outside the housing are bent downward along the peripheral surface of the exterior resin (6).

The anode lead (2) includes a lead portion (21) and a tip portion (22), and when the anode lead frame (41) is welded, the tip portion (22) is crushed into a flat plate shape.
Japanese Patent Publication No. 2003-163136

  The solid electrolytic capacitor (1) according to the conventional example is often used in a high frequency circuit, and it is required to lower the ESR (equivalent series resistance) of the solid electrolytic capacitor (1). As a measure for reducing the ESR, it is conceivable to increase the diameter of the anode lead (2) to reduce the electrical resistance of the entire anode lead.

  However, when the anode and cathode lead frames are pulled out from the center of the housing, the capacitor element (3) is attached to both lead frames (41) and (42) as shown in FIG. The capacitor element (3) is attached in a tilted state. When the capacitor element (3) is attached to both lead frames (41) and (42) in a tilted state, the lead frame (41) and (42) contact with the anode lead (2) and the peripheral surface of the capacitor element (3). The area becomes smaller and the ESR increases. Further, when the element (3) is housed while being tilted with respect to the lead frames (41) and (42), the load applied to the capacitor element (3) increases, and the leakage current increases.

  An object of the present invention is to solve the above problems, eliminate the inclination of the capacitor element when connected to the lead frame, and provide a suitable connection means between the anode lead and the anode lead frame.

In order to solve the above-mentioned problems, the present invention provides a capacitor element in which a dielectric oxide film, a solid electrolyte layer, a carbon and a silver paste layer are sequentially formed on the surface of an anode body made of a valve metal in which an anode lead is implanted. An anode lead frame connected to the anode lead; a cathode lead frame connected to the cathode lead layer; and a rectangular parallelepiped shape around the capacitor element, leaving a part of the anode lead frame and the cathode lead frame. In a solid electrolytic capacitor comprising an exterior resin formed by coating, and an anode lead frame and a cathode lead frame drawn from the center in the height direction of the exterior resin,
The anode lead includes a lead portion and a tip portion connected to the sintered body, and the tip portion has a flat joint surface joined to the anode lead frame, and the joint surface is perpendicular to the anode lead frame. Is characterized by being above the center plane of the drawer.
The solid electrolytic capacitor according to the present invention eliminates the inclination between the capacitor element and the anode lead frame that occurs when the anode lead frame and the anode lead tip are joined. The width of the flat surface from the end surface of the tip portion to the sintered body is larger than the width of the joint surface.

Further, the method for producing a solid electrolytic capacitor of the present invention comprises a solid body comprising an anode body in which an anode lead is planted, and an anode lead frame connected to a flat joint surface provided at the tip of the anode lead. This is a method of manufacturing an electrolytic capacitor. A step of planting the member serving as the anode lead to the anode body, said member, together with the addition of a first pressure to the one end portion in a direction perpendicular to a running direction of said member at a portion corresponding to the tip portion The second end larger than the first pressure is applied to the other end opposite to the one end so as to be crushed from the other end and at one end from the center in the vertical direction. A step of forming the bonding surface located on the portion side, and a step of connecting the bonding surface and the anode lead frame in a state parallel to each other .

In the step of forming the joint surface, a flat surface located on the one end side is further formed by crushing from the one end side, and the width dimension of the flat surface is made larger than the width dimension of the joint surface in the extending direction. Can do.

  According to the configuration of the above invention, when the anode lead having a large diameter is used, the anode lead and the anode lead frame are connected in parallel, so that there is no inclination between the anode lead frame and the capacitor element, and the anode lead frame and the anode lead. In addition, the increase in ESR due to the reduction in the contact area between the capacitor element and the cathode lead frame is eliminated. In addition, since it is housed in a state where there is no inclination between the capacitor element and the cathode lead frame, a load applied to the capacitor element is reduced, and an increase in leakage current can be prevented.

   Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  In the solid electrolytic capacitor, as shown in FIG. 4, a dielectric oxide film, a cathode layer, and a cathode lead layer are sequentially formed on the surface of the sintered body on which the anode lead (2) is implanted, and the capacitor element (3) is formed. Formed. Here, the sintered body used tantalum, but a valve metal such as niobium, titanium, and aluminum may be used, and the anode lead (2) is made of the same valve metal as the sintered body. .

  Further, polypyrrole was used as the cathode layer, and carbon and silver paste were used as the cathode lead layer.

  As the cathode layer, not only polypyrrole but also conductive polymers such as polythiophene, polyaniline, and polyfuran, TCNQ (7,7,8,8-tetracyanoquinodimethane) complex salt, and the like may be used.

  Next, as shown in FIG. 1, the anode lead is formed into a shape that can be easily joined to the anode lead frame. At that time, the pressure applied to the contact point between the tip of the anode lead and the jig is crushed up and down the tip (22) with the lower part (221) larger than the lower part (221) and the upper part (222). The joining surface of the anode lead tip (22) with the anode lead frame (41) is formed above the center of the anode lead extraction part (21) in the vertical direction of the anode lead frame (41).

  Thereafter, the bonding surface of the anode lead tip is bonded to the anode lead frame (41) by resistance welding or the like, and the cathode lead layer of the capacitor element (3) and the cathode lead frame (42) are used using a conductive adhesive (5). Each of them is connected, leaving a part of the anode lead frame (41) and the cathode lead frame (42), and housing the capacitor element in the shape of a rectangular parallelepiped with the exterior resin (6). Here, the bipolar lead frames (41) and (42) are made of an alloy containing copper, an alloy of iron and nickel, or the like.

   The outer resin (6) was pulled out from the center in the height direction, and the bipolar lead frames (41) and (42) were bent downward along the peripheral surface of the housing to obtain a solid electrolytic capacitor.

   In the manufacturing process of the solid electrolytic capacitor, when crushing the tip end portion (22) of the anode lead, a jig having a shape as shown in FIG. 6 (a) is used. The jig includes an upper portion (71a) along the shape of the tip end portion (22) of the anode lead and a lower portion (72a) of a substantially rectangular parallelepiped. When the tip portion (22) is crushed using the jig, the contact area between the anode lead tip portion (22) and the jig upper portion (71a) is more than the portion where the tip portion (22) and the jig lower portion (72a) are in contact with each other. Since the pressure applied to the lower end of the tip (22) becomes larger than the pressure applied to the upper end, the joint surface is deformed as shown in FIG. 1 (a) when crushed as shown in FIG. 6 (b). The lead portion (21) is formed above the vertical center of the anode lead frame (41). Further, when viewed from the end surface of the anode lead tip (22) from the shape of the jig, as shown in FIG. 1B, the upper portion of the anode lead tip (22) has a curved surface and a flat joining surface.

  In the manufacturing process of Example 1, when crushing the tip portion (22) of the anode lead, a solid electrolytic capacitor is obtained in the same manner as in Example 1 except that a jig having a shape as shown in FIG. Was made. The jigs are both substantially rectangular parallelepiped upper part (71b) lower part (72b), and the width dimension Y from the end surface of the anode lead tip part (22) of the lower part (72b) to the sintered body direction is the upper part (71b). It is characterized by being smaller than the width dimension X. When the tip of the anode lead (22) is crushed by using the jig, the pressure applied downward is larger than the pressure applied upward of the anode lead tip (22). When crushed, as shown in FIG. 2 (a), the joining surface is formed above the center in the vertical direction of the lead frame (41) (42) of the anode lead extraction layer (21). Further, due to the shape of the jig, the anode lead tip (22) has a flat joint surface and a flat surface substantially parallel to the tip, and when viewed from the vertical direction of the lead frame (41) (42), FIG. b) When viewed from the end face direction of the tip portion (22), the shape shown in FIG. 2 (b) is obtained.

  By adopting the configuration of the first and second embodiments, since the anode lead and the anode lead frame are connected in parallel, the inclination of the capacitor element and the cathode lead frame is improved and becomes substantially parallel, and the load on the capacitor element is reduced. Is done. Furthermore, the inclination between the anode lead and the anode lead frame is also improved, and the ESR can be reduced by increasing the contact area.

  Moreover, the said Example is for demonstrating this invention, Comprising: It should not be understood that the invention as described in a claim is limited or the range is reduced.

It is the side view of the anode lead of this invention Example 1, and a front view. It is the side view and front view of an anode lead of Example 2 of this invention. Sectional drawing of the conventional solid electrolytic capacitor. Sectional detail drawing of a capacitor | condenser element. Connection state of capacitor element and lead frame in the conventional method. It is the front view and perspective view which show the jig used in order to crush an anode lead front-end | tip part in this invention Example 1. FIG. It is the front view and perspective view which show the jig used in order to crush an anode lead front-end | tip part in Example 2 of this invention.

Explanation of symbols

(1) Solid electrolytic capacitor
(2) Anode lead
(21) Anode lead lead-out part
(22) Anode lead tip / capacitor element
(31) Anode body
(32) Dielectric oxide film
(33) Solid electrolyte layer
(34) Carbon layer and silver paste layer
(41) Anode lead frame
(42) Cathode lead frame
(5) Conductive adhesive
(6) Exterior resin
(71a) Jig used to crush the tip of the anode lead
(72b) Jig used to crush the tip of the anode lead

Claims (3)

A capacitor element in which a dielectric film, a cathode layer, and a cathode lead layer are sequentially formed on the surface of a sintered body made of a valve action metal in which an anode lead is implanted; an anode lead frame connected to the anode lead; A cathode lead frame connected to the cathode lead layer; and an exterior resin formed by covering the capacitor element in a rectangular parallelepiped shape with the anode lead frame and a part of the cathode lead frame being covered. In the solid electrolytic capacitor in which the anode lead frame and the cathode lead frame are drawn from the center in the height direction, respectively.
The anode lead includes a lead portion and a tip portion connected to the sintered body, and the tip portion has a flat joint surface joined to the upper surface of the anode lead frame, and the joint surface is the anode lead. The vertical direction of the frame is above the center plane of the drawer,
The tip portion has the joint surface and a flat surface substantially parallel to the joint surface, and the width dimension of the flat surface from the end face of the tip portion toward the sintered body is larger than the width dimension of the joint surface. Solid electrolytic capacitor characterized by A method for producing a solid electrolytic capacitor comprising: an anode body in which an anode lead is planted; and an anode lead frame connected to a flat joint surface provided at a tip portion of the anode lead.
Planting a member to be an anode lead in the anode body ;
A first pressure is applied to one end in a direction perpendicular to the extending direction of the member at a portion corresponding to the tip of the member, and a first pressure is applied to the other end facing the one end. Forming the joining surface formed by crushing from the other end side by applying a larger second pressure and positioned on one end side than the center in the vertical direction;
Connecting the joining surface and the anode lead frame in a mutually parallel state;
A method for producing a solid electrolytic capacitor, comprising: In the manufacturing method of the solid electrolytic capacitor of Claim 2,
In the step of forming the joining surface, a flat surface located on the one end side is further formed by crushing from the one end side, and the width dimension of the flat surface in the extending direction is equal to that of the joining surface. A method for manufacturing a solid electrolytic capacitor, wherein the solid electrolytic capacitor is larger than a width dimension.