JP2009224558A - Laminated solid-state electrolytic capacitor and its manufacturing method - Google Patents

Abstract

Disclosed is a large-capacity multilayer solid electrolytic capacitor that is less prone to leakage current failure and has excellent performance, and a method for manufacturing the same.
A plurality of capacitor elements C1 to C4 having anode parts P1 to P4 on one side and cathode parts N1 to N4 on the other side are stacked with the anode parts protruding so that the positions of the cathode parts are aligned, A laminated solid electrolytic capacitor in which an anode portion protruding from a cathode body laminate is bent and bundled at at least one convergence position, and the bundled anode portions are conductively joined to each other, and the bundle of anode portions is bundled The length of the anode portion is increased every time the distance from the convergence position increases.
[Selection] Figure 4

Description

  In the present invention, a plurality of capacitor elements having an anode portion on one side and a cathode portion on the other side are stacked so that the positions of the cathode portions are aligned, and the anode portion protruding from the cathode body laminate is bent. The present invention relates to a stacked solid electrolytic capacitor in which at least one position is bundled, and the bundled anode portions are conductively joined, and a method for manufacturing the same.

  The solid electrolytic capacitor includes an oxide film layer serving as a dielectric on the surface of a valve metal plate such as aluminum or tantalum. One side of the valve metal plate is configured as an anode, and the other side is configured as a cathode in which a solid electrolyte layer is formed on an oxide film layer. For example, manganese dioxide, a TCNQ complex, a conductive polymer, or the like is used as the solid electrolyte layer (see, for example, Patent Document 1).

  In recent years, with the miniaturization and high frequency of electronic devices, solid electrolytic capacitors using a conductive polymer as a solid electrolyte have been developed in order to realize low impedance in a high frequency region. Since this solid electrolytic capacitor uses a conductive polymer as a solid electrolyte, the equivalent series resistance / equivalent series inductance (hereinafter referred to as ESR / ESL) is lower than that of a solid electrolytic capacitor using manganese dioxide or the like. Moreover, since this solid electrolytic capacitor can realize a large-capacity and small-sized solid electrolytic capacitor, its application is wide and various improvements have been attempted (for example, see Patent Document 2).

  However, as the voltage of the CPU of the computer is reduced and the speed is increased, the current flowing through the capacitor is greatly increased particularly in a high frequency region, so that the heat generated by the ESR / ESL of the solid electrolytic capacitor and the current is increased, and the capacitor Failure is likely to occur. For this reason, the solid electrolytic capacitor is required to have high-speed transient mode responsiveness and to have a large capacity and low ESR / ESL (for example, see Patent Document 2).

As a method for realizing a large capacity and low ESR / ESL, there is a method in which a capacitor element has a laminated structure and the number of laminated layers is increased. As an example of a laminated structure of a multilayer solid electrolytic capacitor using a conductive polymer as a solid electrolyte, a plate-shaped capacitor element having an anode part and a cathode part made of a solid electrolyte layer is used as anode parts, A two-terminal configuration in which a plurality of cathode portions are stacked so that the cathode portions overlap each other and a potential extraction terminal plate is connected to each electrode is known (for example, see Patent Documents 2 and 3).
As another example, a three-terminal configuration is known in which a plurality of layers are arranged so that the direction of the anode exposed portion is alternately left and right with the cathode portion as the center, and a potential extraction terminal plate is connected to each electrode. (See, for example, Patent Document 4).
Japanese Patent No. 2996992 JP 2003-45753 A JP 2000-68158 A JP 2007-1116064 A

In the conventional multilayer solid electrolytic capacitor, the cathode portion of the capacitor element is made of a solid electrolyte or the like, and thus is slightly thicker than the anode portion.
On the other hand, the anode portion of the capacitor element is bent and bundled at a predetermined position (hereinafter, such a position is referred to as “converging position”), and is welded by resistance welding, laser welding, or the like. However, in the case of the capacitor element laminated in a plurality as described above, the thickness of the cathode part is larger than the thickness of the anode part, so the number of laminations increases and the distance between the convergence position and the anode part of the outermost layer is large. Become.
Therefore, in order to bend and bundle the anode parts of the stacked capacitor elements at the convergence position, it is necessary to apply a pressing force to the anode parts so as to deform the anode parts over this large distance. For this reason, stress and distortion are generated in the anode and cathode, and as a result, there is a problem that leakage current occurs and the defective rate of the capacitor increases.

  SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems. By relaxing the stress and distortion generated in the anode and cathode during capacitor production, a leakage current failure is less likely to occur, and a large-capacity laminated solid that has excellent performance. An object of the present invention is to provide an electrolytic capacitor and a manufacturing method thereof.

In order to achieve the above object, according to the present invention, a plurality of capacitor elements having an anode part on one side and a cathode part on the other side are stacked so that the anode part protrudes and is stacked so that the positions of the cathode parts are aligned. A laminated solid electrolytic capacitor in which the anode portion protruding from the laminated body is bent, the end portions of the anode portion are bundled in at least one convergence position, and the bundled anode portions are conductively joined together,
Provided is a multilayer solid electrolytic capacitor characterized in that the length of the anode part becomes longer for each set of bundled anode parts as the distance from the convergence position increases.

In the above configuration, the plurality of capacitor elements are stacked such that the positions of the cathode portions are aligned and the protruding directions of the anode portions are aligned, or the protruding directions of the anode portions are alternately reversed. Preferably it is.
Moreover, it is preferable that the anode part spaced apart from the convergence position has a curved portion that is curved in the vicinity of the center position in the projecting direction, and the ends are bundled at the convergence position in a curved state.

In order to achieve the above object, the present invention also provides a plurality of capacitor elements each having an anode part on one side and a cathode part on the other side, projecting and stacking the anode parts so that the positions of the cathode parts are aligned, A laminated solid electrolytic capacitor in which an anode portion protruding from the laminated body is bent, the end portions of the anode portion are bundled at at least one convergence position, and the bundled anode portions are conductively joined to form an anode potential extraction terminal. A manufacturing method comprising:
Provided is a method for manufacturing a multilayer solid electrolytic capacitor, characterized in that the length of the anode part for each set of capacitor elements bundled with the anode part becomes longer as the capacitor element moves away from the convergence position where the anode part is bundled. .

In the above configuration, a plurality of capacitor elements may be stacked such that the positions of the cathode portions are aligned and the directions of the protruding directions of the anode portions are aligned, or the directions of the protruding directions of the anode portions are alternately opposite. preferable.
In addition, the anode part that is separated from the convergence position is curved in the protruding direction in the vicinity of the center position, the ends of the anode part are bundled at at least one convergence position, and the bundled anode parts are conductively joined together. Thus, it is preferable to form an anode potential extraction terminal.

  According to the present invention, when the anode part protruding from the laminate of the cathode part is bent and bundled into at least one position (convergence position), the length of the anode part for each set of bundled anode parts is set to the convergence value. Since the length is increased as the distance from the position increases, the stress and strain applied to each anode part and each cathode part can be reduced when resistance welding or laser welding is performed on the anode part. An increase in leakage current of the electrolytic capacitor can be prevented.

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

FIG. 1 is a perspective view of one capacitor element constituting a multilayer solid electrolytic capacitor according to one embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view taken along line XX ′ of the capacitor element of FIG. It is.
Referring to FIG. 2, capacitor element C includes valve action metal plate 1 made of a thin plate roughened with aluminum, tantalum or the like. An oxide film layer 2 serving as a dielectric is formed on the entire surface of the valve action metal plate 1. One side of the valve metal plate 1 constitutes an anode part P, the other side of the valve metal plate 1 has a solid electrolyte layer 3 on the oxide film layer 2, a carbon layer 4 on it, and a carbon layer 4 thereon. The silver layer 5 is sequentially coated to form the cathode portion N. The solid electrolyte layer 3 is a layer formed by chemical polymerization of an electrolyte containing a conductive polymer such as polyethylene dioxythiophene (PEDT).

  In this embodiment, from a functional point of view, the entire valve action metal plate 1 is an anode, while the portion composed of the solid electrolyte layer 3, the carbon layer 4, and the silver layer 5 is collectively referred to as a cathode portion N, A portion where the cathode portion N of the valve metal plate 1 is not formed, that is, a portion protruding to the left in FIG. 2 (anode exposed portion) is referred to as an anode portion P for convenience.

  An insulating masking member 6 is provided on the surface of the oxide film layer 2 of the valve action metal plate 1 at an appropriate position between the anode part P and the cathode part N in the valve action metal plate 1. And the cathode portion N are completely insulated and isolated.

Next, a method for manufacturing a capacitor element will be described below with reference to a manufacturing example in which aluminum is used as a valve metal plate.
A long aluminum foil having a thickness of 0.1 mm whose surface has been electrochemically roughened is anodized for about 60 minutes while applying a voltage of 10 V in an aqueous solution of ammonium adipate to form a dielectric on the surface. An oxide film layer is formed. As shown in FIG. 1, the aluminum foil on which the oxide film layer is formed is cut into a plane size having a width of 11 mm and a length of 11 mm.
Next, as shown in FIG. 2, the left and right regions (anode portion P and cathode portion N) are separated by applying a masking member 6 such as an insulating resin in an appropriate position in the circumferential direction. Thereafter, the side portion of the valve metal plate 1 exposed by the above-described cutting is oxidized for about 30 minutes while applying a voltage of 7 V again in the aqueous solution of ammonium adipate. An oxide film layer is formed. Thereafter, the solid electrolyte layer 3, the carbon layer 4, and the silver layer 5 are provided on the right side of the masking member 6 to form the cathode portion N, and the capacitor element C is manufactured.

  Next, the effect of the multilayer solid electrolytic capacitor according to the present invention was confirmed. Details thereof will be described below with reference to FIGS.

Example 1
The four capacitor elements C1, C2, C3, and C4 having the same rating manufactured by the above-described method are aligned so that the positions of the cathode portions N1, N2, N3, and N4 are aligned in the stacking direction (the main portion of each cathode portion is A four-layered solid electrolytic capacitor was fabricated in which the surfaces were sequentially stacked so that the surfaces matched. FIG. 3 shows a perspective view thereof. Referring to FIG. 3, capacitor elements C <b> 1 to C <b> 4 are stacked so that the protruding directions of anode parts P <b> 1 to P <b> 4 are alternately opposite about the stacked body of cathode parts N <b> 1 to N <b> 4. Furthermore, the stacked body of the cathode portions N1 to N4 is electrically joined closely through a conductive adhesive (not shown).
As shown in FIG. 3, the lengths of the anode parts P1 to P4 protruding from the laminated body of the matched cathode parts N1 to N4 are gradually increased toward the upper side of the multilayer solid electrolytic capacitor. Specifically, the length of the anode part P2 of the capacitor element C2 is 0.5 mm longer than the anode part P1 of the capacitor element C1, and the lengths of the anode parts P3 and P4 of the capacitor elements C3 and C4 are also lower layers. Each is 0.5 mm longer than the anode part of the capacitor element. Thereby, compared to the case where the lengths of the anode portions P1 to P4 are all the same, when the anode portions are conductively joined, stress, strain, and the like on the anode portion and the cathode portion are easily reduced.
That is, as will be described later, the end portions of the anode portions C1 to C4 are joined so as to converge at a predetermined position (convergence position). Here, as the anode part is arranged at a position farther from the convergence position (as the number of stacked capacitor elements increases), the end of the anode part is joined at the convergence position. However, when the length in the protruding direction of the anode part is the same, stress is generated in the anode part and the cathode part, leading to an increase in leakage current due to damage to the oxide film layer.
On the other hand, according to this embodiment, the length of the anode portion in the protruding direction is increased as the anode portion is arranged at a position away from the convergence position. For this reason, when bundling the edge part of an anode part in a convergence position, the curve of an anode part is decreased and the stress to a cathode part decreases. As a result, the stress at the time of joining can be relieved and an increase in leakage current can be prevented.
In addition, although the length of anode part P1-P4 showed the example which becomes long gradually toward the upper direction of a multilayer solid electrolytic capacitor, this invention is not limited to this, The anode part bundled The length of the anode portion for each set may be configured to become longer as the distance from the convergence position where the anode portions are bundled.

4 is a cross-sectional view of the four-layer laminated solid electrolytic capacitor of FIG. 3, where (a) shows a state before resistance welding of the anode part, and (b) shows a state of being sheathed with mold resin after resistance welding of the anode part. Is. As shown in FIGS. 4 (a) and 4 (b), the cathode portions N1 to N4 of the four capacitor elements are sequentially stacked so that their positions are aligned with each other. Jointly.
Further, the cathode potential extraction terminal plate 8 is densely and electrically connected to the lower surface of the cathode portion N1 located at the lowest position via a conductive adhesive. On the other hand, for the anode parts P1 to P4 of each element, the anode parts P1 and P3 are on the left side and the anode parts P2 and P4 are on the right side so as to protrude from the laminated body of the matched cathode parts N1 to N4. That is, it arrange | positions so that it may protrude in the opposite direction alternately. Here, the internal structures (solid electrolyte layer 3, carbon layer 4 and silver layer 5) of cathode portions N1 to N4 are the same as those shown in FIG.
In this embodiment, anode portions P1 and P3 projecting to the left side and anode portions P2 and P4 projecting to the right side are respectively provided on the left and right sides of the laminate of the cathode portions N1 to N4. , 7 'resistance welding. The welding surface (upper surface) of the anode potential extraction terminal plates 7 and 7 ′ is disposed substantially flush with the bonding surface (upper surface) of the cathode potential extraction terminal plate 8 with the cathode portion N 1. Specifically, the anode potential extraction terminal plates 7 and 7 ′ are provided at positions below the lower surfaces of the anode portions C1 and C2, respectively.
At this time, the anode parts P2 to P4 (corresponding to “the anode part that is separated from the convergence position” in the present application) are positioned below the anode part in the vicinity of the positions 10 and 10 ′ shown in FIG. In addition, it is fixed through a wire in the width direction of the capacitor element, and is welded to the anode potential extraction terminal plates 7 and 7 ′ while holding the anode portion so that it is not greatly bent during welding. In other words, in the protruding direction of the anode part (left and right direction in FIG. 4), the bending is performed so that the curved portion is positioned on the anode parts P3 and P4 that are separated from the insulating masking part 6. Preferably, there is a curved portion at a position closer to the center of each of the anode portions P3 and P4, and the ends are bundled at a convergence position on the welding surface of the anode potential extraction terminal plates 7 and 7 ′ in the curved state. As described above, in this embodiment, the bending of the cathode portion in the vicinity of the insulating masking member 6 is prevented by bending from the anode portion away from the insulating masking member 6.

  The oxide film layer 2 is formed on the surfaces of the anode parts P1 to P4. However, when resistance welding is performed, the oxide film layer 2 on the joint surface is dissolved by the temperature at the time of welding, so the anode parts P1 to P4. And the anode potential extraction terminal plates 7 and 7 'are electrically and electrically conductively joined. In the case where the anode parts are joined together by an adhesive means other than welding such as an adhesive, it is desirable that the oxide film layer 2 on the joint surface is peeled off beforehand by polishing or other means.

  Further, the entire laminated structure is molded with a resin, and a potential extraction terminal plate that can be connected to an external circuit is provided on the four-layered solid electrolytic capacitor of Example 1.

(Example 2)
In the same manner as in Example 1, a multilayer solid electrolytic capacitor in which the number of capacitor elements was 8 was produced. FIG. 5 shows a cross-sectional view of an 8-layered solid electrolytic capacitor in Example 2 of the present invention. (The illustration of the mold resin is omitted.)

(Example 3)
A multilayer solid electrolytic capacitor having 12 capacitor elements was manufactured in the same manner as in Example 1. (The illustration is omitted.)

(Conventional example 1)
In the same manner as in Example 1, a conventional multilayer solid electrolytic capacitor having four stacked capacitor elements was produced. 6A and 6B are cross-sectional views of a conventional four-layered solid electrolytic capacitor. FIG. 6A shows a state before resistance welding of the anode part, and FIG. 6B shows a state after resistance welding of the anode part (mold). The illustration of the resin is omitted). In FIG. 6, the lengths of the anode portions P1 to P4 of the four capacitor elements C1 to C4 are all the same.

(Conventional example 2)
A conventional multilayer solid electrolytic capacitor having eight capacitor elements was manufactured in the same manner as in Conventional Example 1. (The illustration is omitted.)

(Conventional example 3)
A conventional multilayer solid electrolytic capacitor having 12 stacked capacitor elements was produced in the same manner as in Conventional Example 1. (The illustration is omitted.)

  The performances of the multilayer solid electrolytic capacitors of Examples 1 to 3 of the present invention and the multilayer solid electrolytic capacitors of Conventional Examples 1 to 3 were compared. Table 1 shows the number (defective rate) satisfying the leakage current standard among 100 products for each example.

As can be seen from Table 1, in Examples 1 to 3, the number satisfying the leakage current standard is larger than that in Conventional Examples 1 to 3 (the defect rate is low). It can be seen that the leakage current failure is reduced by increasing the length of each bundled anode part as the distance from the convergence position increases.
As can be seen from Table 1, the effect of the present invention increases as the number of stacked layers increases.

  The configuration of the present invention is not limited to the above-described embodiment. For example, in the above-described examples, thiophene and ferric dodecylbenzenesulfonate were used as the monomer and the oxidizing agent, but known monomers such as pyrrole and aniline were used as the monomer, and ferric butylnaphthalenesulfonate was used as the oxidizing agent. The same effect can be obtained by using a known oxidizing agent such as ferric paratoluenesulfonate.

  In the above-described embodiments, aluminum is used as the capacitor anode material, but the same effect can be obtained by using a valve metal such as tantalum or niobium.

  Furthermore, in the above-described embodiment, the anode potential extraction terminal plate or the cathode potential extraction terminal plate is provided below the multilayer solid electrolytic capacitor. However, depending on the usage state and application of the capacitor, the multilayer solid electrolytic capacitor is used. The capacitor may be provided on the side or above the capacitor, and the installation location is arbitrary.

  Further, in the above embodiment, the protruding direction of the anode part is arranged opposite to each other with the cathode part stack as the center, but the anode part may be arranged only on one side, and the protruding direction of the anode part The direction is arbitrary.

  Although the present invention has been described with respect to a three-terminal structure, the present invention is not limited to this, and is also effective for a multilayer solid electrolytic capacitor having a two-terminal structure or a multi-terminal structure having four or more terminals.

It is a perspective view of one capacitor | condenser element which comprises the multilayer type solid electrolytic capacitor by one Example of this invention. FIG. 2 is an enlarged cross-sectional view taken along line X-X ′ of the capacitor element of FIG. 1. It is a perspective view of the 4 lamination type solid electrolytic capacitor in Example 1 of the present invention. FIG. 4 is a cross-sectional view of the four-layer solid electrolytic capacitor of FIG. 3, where (a) shows a state before resistance welding of the anode part, and (b) shows a state covered with mold resin after resistance welding of the anode part. It is sectional drawing of the 8 sheet | seat type solid electrolytic capacitor in Example 2 of this invention. It is sectional drawing of the 4 sheet | seat type solid electrolytic capacitor of a prior art example, (a) is before resistance welding of an anode part, (b) shows the state after resistance welding of an anode part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve action metal plate 2 Oxide film layer 3 Solid electrolyte layer 4 Carbon layer 5 Silver layer 6 Insulating masking member 7 Anode potential extraction terminal plate 7 ′ Anode potential extraction terminal plate 8 Cathode potential extraction terminal plate 9 Mold resin 10 Anode portion Curved position 10 ′ Curved position C of anode part Capacitor elements C1 to C8 Capacitor element P Anode part (anode exposed part)
P1-P8 Anode part (exposed anode part)
N Cathode part N1-N8 Cathode part

Claims (6)

A plurality of capacitor elements having an anode part on one side and a cathode part on the other side, the anode part protruding and stacked so that the position of the cathode part is aligned, and the anode protruding from the laminate of the cathode part A laminated solid electrolytic capacitor in which a portion is bent, an end portion of the anode portion is bundled at at least one convergence position, and the bundled anode portions are conductively joined to each other;
The multilayer solid electrolytic capacitor, wherein the length of the anode portion becomes longer as the anode portion is bundled away from the convergence position.   The plurality of capacitor elements are stacked such that the positions of the cathode portions are aligned and the protruding directions of the anode portions are aligned, or the protruding directions of the anode portions are alternately opposite. The multilayer solid electrolytic capacitor according to claim 1, wherein:   The anode part that is separated from the convergence position has a curved portion that is curved in the vicinity of the center position in the projecting direction, and the ends are bundled at the convergence position in a curved state. The multilayer solid electrolytic capacitor according to claim 1 or 2. A plurality of capacitor elements each having an anode part on one side and a cathode part on the other side are stacked with the anode part protruding so that the position of the cathode part is aligned, and protruding from the laminate of the cathode part Is a method of manufacturing a multilayer solid electrolytic capacitor in which ends of the anode part are bundled in at least one convergence position, and the bundled anode parts are conductively joined to form an anode potential extraction terminal.
A multilayer solid electrolytic capacitor characterized in that, for each set of capacitor elements that bundle the anode parts, the length of the anode part becomes longer as the distance from the convergence position where the capacitor elements bundle the anode parts is increased. Manufacturing method.   The plurality of capacitor elements are stacked such that the positions of the cathode portions are aligned and the protruding directions of the anode portions are aligned, or the protruding directions of the anode portions are alternately opposite. The method for producing a multilayer solid electrolytic capacitor according to claim 4, characterized in that:   The anode parts that are separated from the convergence position are curved in the protruding direction in the vicinity of the center position, the ends of the anode parts are bundled at at least one convergence position, and the bundled anode parts are conductively joined together. 6. The method for producing a multilayer solid electrolytic capacitor according to claim 4, wherein an anode potential extraction terminal is formed.

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