JPWO2013128951A1 - Solid electrolytic capacitor and manufacturing method thereof - Google Patents

Abstract

A dielectric layer (2), a conductive polymer layer (3), a carbon layer (cathode underlayer) (4), and a silver electrode layer (cathode outermost layer) (5) are formed on the surface of the valve metal substrate (1). An anode conducting material (70) and a silver electrode layer having a plurality of capacitor elements (11) formed in this order and conducting to the valve metal substrate (1) in a state where the plurality of capacitor elements (11) are laminated. (Cathode outermost layer) A cathode conducting material (80) conducting to (5) is provided. The cathode conductive material (80) has a notch (81C) at the abutting portion where the end face of the multilayer body of the capacitor element (11) abuts, and the plurality of capacitor elements (11) are electrically connected to the notch (81C). A conductive member (8) is provided for connection. Thereby, the stress added to the laminated body of a capacitor element is suppressed.

Description

  The present invention relates to a chip-type solid electrolytic capacitor and a method for manufacturing the same.

  As a chip-type solid electrolytic capacitor, for example, the type shown in Patent Document 1 is known.

  FIG. 6 is an exploded perspective view of the main part of the solid electrolytic capacitor disclosed in Patent Document 1. In FIG. 6, the anode portion 22 of each capacitor element 20 is formed of aluminum which is a valve action metal substrate, and its surface is roughened (enlarged) by etching. A dielectric layer is formed on the roughened valve metal substrate by chemical conversion treatment (anodic oxidation). A solid electrolytic capacitor that can be surface-mounted on a circuit board or the like is configured by joining an assembly of a plurality of capacitor elements 20 to the cathode connection member 40 and the anode connection member 30.

  The cathode connection member 40 has a shape including a support portion 42 and a cathode contact portion 44 rising from the support portion 42, and the cathode portion 24 is electrically connected to the cathode connection member 40. Further, the anode connecting member 30 has a shape including an anode contact portion 34 in which a slit 36 is formed and a support portion 32, and is laminated from the opposite side of the anode contact portion 34 to the side where the anode portion 22 is contacted. The laser spot 38 a is irradiated to the slit portion 38 in a direction crossing the stacking direction of the capacitor elements 20 of the body 60 to be electrically connected.

Japanese Patent Laid-Open No. 2007-258214

  Generally, a chip-type solid electrolytic capacitor for surface mounting is packaged with an exterior resin. In the example shown in FIG. 6, the laminate 60 is placed on the cathode connection member 40, and after the anode connection member 30 is connected, resin molding is performed.

  However, as shown in FIG. 6, in the conventional solid electrolytic capacitor including the cathode connection member 40 having an L-shaped cross section, the entire end surface of the multilayer body 60 is covered with the contact portion 44 of the cathode connection member 40. Therefore, the stress from the exterior resin becomes a problem. That is, stress is applied to the joint portion between the contact portion 44 of the cathode connection member 40 and the laminate 60 due to expansion and contraction due to heat or the like when the solid electrolytic capacitor is mounted on the printed wiring board. In addition, stress is applied to the joint portion between the contact portion 44 of the cathode connection member 40 and the laminate 60 also when molding the exterior resin. These stresses may cause a problem that the capacitor elements 20 constituting the laminate are separated from each other.

  An object of the present invention is to provide a solid electrolytic capacitor in which the above-mentioned problem is regarded as a problem, and the stress applied to the laminated body of capacitor elements is suppressed to eliminate problems such as separation of capacitor elements.

(1) The solid electrolytic capacitor of the present invention is
A multilayer body in which a plurality of capacitor elements each provided with a dielectric layer, a conductive polymer layer, and a cathode layer are laminated on the surface of the valve metal base;
An anode conducting material conducting to the valve metal substrate and a cathode conducting material conducting to the cathode layer,
In a solid electrolytic capacitor in which at least the laminate is coated with an exterior resin,
At least the cathode conducting material has a notch in a contact portion with which the cathode layer contacts,
A conductive member for electrically connecting the plurality of capacitor elements constituting the multilayer body is provided in the cutout portion.

(2) For example, the conductive member is a conductive paste. Thus, the notch portion is formed in the cathode conductive material, and laser spot welding is not performed when the cathode portions of the capacitor elements or the cathode portions are electrically connected via the cathode conductive material. As a result, thermal denaturation of the conductive polymer layer can be avoided.

(3) It is preferable that the conductive member does not overlap the cathode conductive material. Thereby, the thickness of the exterior resin coated on the outside of the cathode contact portion is not reduced, and a predetermined strength can be ensured without increasing the external dimensions.

(4) It is preferable that the said notch is the part which bent a part of said cathode conduction | electrical_connection material or the said anode conduction | electrical_connection material. According to this structure, the bent portion can be used as an external terminal, and the formation of the notch and the formation of the external terminal can be performed simultaneously.

(5) The method for producing the solid electrolytic capacitor of the present invention comprises:
A multilayer body in which a plurality of capacitor elements each provided with a dielectric layer, a conductive polymer layer, and a cathode layer are laminated on the surface of the valve metal base;
An anode conducting material conducting to the valve metal substrate and a cathode conducting material conducting to the cathode layer,
A method for producing a solid electrolytic capacitor in which at least the laminate is coated with an exterior resin,
The cathode conducting material has a notch in a portion where end faces of the capacitor element laminate are close to each other,
Directly stacking and mounting the plurality of capacitor elements on the cathode conducting material;
Applying a conductive member to an end face of the capacitor element laminate mounted on the cathode conducting material;
It is provided with.

  According to the manufacturing method described above, by directly stacking and mounting the capacitor element on the cathode conductive material using one mounting machine, it is possible to reduce manufacturing machines and man-hours and reduce costs.

(6) The conductive paste is preferably ejected by a jet dispenser. In the case of injection coating using a jet dispenser, the accuracy of the coating position is high, and the conductive paste can be applied to the minimum necessary area.

(7) It is preferable that the notch is formed in the anode conducting material, and the connecting member that electrically connects the anode part of the capacitor element via the anode conducting material is a welding spot of a laser spot. . Processing time can be shortened by laser spot welding the anode conductive material.

  Since at least the cathode conductive material does not cover the entire end face of the multilayer body of capacitor elements, the stress from the exterior resin applied to the end face of the multilayer body is relieved, and the capacitor elements constituting the multilayer body are prevented from peeling off. it can.

FIG. 1 is a perspective view showing shapes of a cathode conducting material 80, an anode conducting material 70, and an exterior resin 50 of a solid electrolytic capacitor. 2A is a cross-sectional view of the solid electrolytic capacitor 101, and FIG. 2B is a side view as viewed from the cathode contact portion 81 side. (1) to (5) in FIG. 3 are diagrams showing a manufacturing process of the solid electrolytic capacitor. (1) to (6) in FIG. 4 are diagrams illustrating an example of a method for manufacturing the capacitor element 11. (1) to (5) in FIG. 5 are diagrams showing manufacturing steps from assembling a plurality of capacitor elements 11 to forming a final solid electrolytic capacitor. FIG. 6 is an exploded perspective view of the main part of the solid electrolytic capacitor disclosed in Patent Document 1.

  A solid electrolytic capacitor according to an embodiment of the present invention will be described with reference to the drawings in order.

  FIG. 1 is a perspective view showing shapes of a cathode conducting material 80, an anode conducting material 70, and an exterior resin 50 of a solid electrolytic capacitor. However, the capacitor element shown later is not shown in FIG. Moreover, the cathode external terminal portion 82 and the anode external terminal portion 72 show a state before being bent along the outer surface of the exterior resin 50.

  The cathode conducting material 80 includes a cathode contact portion 81, a cathode external terminal portion 82, and a cathode support portion 83. The anode conducting material 70 includes an anode contact portion 71 and an anode external terminal portion 72. The cathode contact portion 81 is formed with three notches 81C. Of these notches 81 </ b> C, the center notch is a portion bent from the cathode contact portion 81 as a part of the cathode external terminal portion 82. Similarly, three cutouts 71 </ b> C are formed in the anode contact portion 71. Of these cutouts 71 </ b> C, the central cutout is a portion bent from the anode contact portion 71 as a part of the anode external terminal portion 72.

  2A is a cross-sectional view of the solid electrolytic capacitor 101, and FIG. 2B is a side view as viewed from the cathode contact portion 81 side. However, in FIG. 2B, the exterior resin represents only its outline.

  In the example shown in FIGS. 2A and 2B, three capacitor elements 11 are stacked on the cathode support portion 83.

  Each capacitor element 11 has a dielectric layer 2, a conductive polymer layer 3, a carbon layer (cathode underlayer) 4, and a silver electrode layer (cathode outermost layer) 5 formed in this order on the surface of the valve metal base 1. It is configured by being. The valve metal base 1 is the anode, and the silver electrode layer 5 is the outermost layer of the cathode. The cathode support portion 83 and the capacitor element 11, and the capacitor elements are bonded to each other via an element bonding material 9.

  In addition, a spacer 6 is provided on the protruding portion of the valve metal base 1 covered with the dielectric layer 2 of each capacitor element 11.

  As shown in FIG. 2B, the conductive member 8 that connects the silver electrode layers of the capacitor element 11 is provided in the cutout portion 81 </ b> C of the cathode contact portion 81.

  FIG. 3 is a diagram illustrating a manufacturing process of a solid electrolytic capacitor. 3 is a left side view and the right side view is a front view. First, as shown by (1) and (2) in FIG. 3, the element bonding material 9 is applied on the cathode support portion 83, and one capacitor element 11 is placed. At that time, alignment is performed by bringing the end of the capacitor element 11 into contact with the cathode contact portion 81. However, it is not always necessary to make it contact. Similarly, as shown in (3) and (4), the application of the element bonding material 9 and the placement of the capacitor element 11 are sequentially repeated to stack a plurality of capacitor elements 11 on the cathode support portion 83. The element bonding material 9 is a conductive or insulating bonding material, such as a silver paste or a resin paste.

  Thereafter, as shown in (5), the silver paste to be the conductive member 8 is ejected from the nozzle head of the jet dispenser and adhered to the laminated body of the capacitor elements 11, and the conductive member (silver electrode) 8 is formed by drying. To do. The conductive member 8 electrically connects the silver electrode layers 5 of the plurality of stacked capacitor elements 11. Here, it is preferable that the landing position of the silver paste does not overlap the cathode contact portion 81. Therefore, the thickness of the exterior resin coated on the outside of the cathode contact portion 81 is not reduced, and a predetermined strength can be ensured without increasing the external dimensions.

  When the element bonding material 9 is insulative, the silver electrode layers 5 of all the capacitor elements may be in contact with the cathode contact portion 81. Even in this case, electrical conduction can be ensured even if the conductive member 8 does not overlap the cathode contact portion 81.

  The anode conducting material 70 is fixed to the jig together with the cathode conducting material 80. In the next step shown in FIG. 3 (5), the anode contact portion 71 is used as the end of the valve metal substrate of the capacitor element 11. Laser spot welding. The conductive polymer layer 3 (see FIG. 2) needs to avoid heat denaturation, and it is desirable that the silver electrode layers 5 are joined together by a method that does not involve heat.

  Next, an example of a method for manufacturing the capacitor element 11 is shown. (1)-(6) of FIG. 4 is a figure which shows the mode in each process. The contents of each process are as follows.

(1) An Al foil 12 having a thickness of, for example, 100 μm is prepared in which a dielectric layer 2 that is an aluminum oxide (Al ₂ O ₃ : dielectric) film is formed on the surface of a valve action metal substrate 1 that is an Al base. . The Al foil 12 has a surface made porous by etching, and an aluminum oxide film of the order of several nm to several tens of nm is formed on the surface inside the porous film. In FIG. 4, the thickness of the dielectric layer (aluminum oxide film) 2 is drawn to the same extent as the valve action metal substrate (Al substrate) 1 for the sake of clarity. The thickness of the valve action metal substrate (Al substrate) 1 is sufficiently larger than the thickness of the dielectric layer (aluminum oxide film) 2.

(2) A metal spacer 6 is welded or pasted on the surface of the Al foil 12.

(3) Punching into a comb-like shape (punching out) so as to obtain an element shape.

(4) The Al foil 12 and the counter electrode 13 are immersed in the ammonium adipate aqueous solution L1, and the voltage of 3.5 V is applied using the Al foil 12 as an anode and the counter electrode 13 as a cathode. That is, an aluminum oxide film is formed on the surface of the Al foil 12 including the cut surface of the Al foil 12 by anodic oxidation.

(5) The Al foil 12 is immersed in the conductive polymer raw material solution L2 to form a conductive polymer film. For example, after immersing the Al foil 12 in an isopropanol solution containing 3,4-ethylenedioxythiophene, the operation of immersing in the mixed solution of ammonium persulfate and sodium anthraquinone-2-sulfonate is repeated 20 times.

(6) After the Al foil 12 is immersed in the carbon paste CP and dried to form a carbon layer having a thickness of 3 μm, it is immersed in a silver paste tank and dried to form a silver electrode layer having a thickness of 20 μm. The carbon layer and the silver electrode layer may be formed by a screen printing method or a spray coating method.

  Thereafter, the capacitor element 11 manufactured through the above steps is directly mounted on the cathode support portion 83, and a plurality of capacitor elements 11 are stacked on the cathode support portion 83. As a result, the assembly can be performed by one mounting machine. That is, as in the conventional assembly process, in the construction method in which the capacitor elements are once stacked on a jig or the like and then the stacked capacitor elements are mounted on the cathode support portion 83, two mounting machines are required. According to this embodiment, it is possible to assemble with a single mounting machine, and it is not necessary to transfer the laminated body of capacitor elements, so that the cost can be reduced.

  Next, an example of a method for producing a final solid electrolytic capacitor by assembling a plurality of capacitor elements 11 will be described. (1)-(6) of FIG. 5 is a figure which shows the mode in each process. The contents of each process are as follows. Here, the details of the steps (2) to (4) are as shown in FIG.

(1) After the step (6) in FIG. 4, the capacitor element is cut out with a laser or a rotary blade.

(2) The capacitor element 11 is laminated on the cathode conducting material 80 with the element bonding material 9 interposed therebetween.

(3) The conductive member 8 is applied to the cathode side end face of the multilayer body of the capacitor element 11.

(4) The anode conductive member 70 is irradiated with laser light, and the anode contact portion 71 is laser spot welded to the end portion of the valve metal substrate of the capacitor element 11.

(5) Seal with exterior resin 50. The exposed cathode external terminal portion 82 and anode external terminal portion 72 are bent along the surface of the exterior resin 50.

  Of course, the present invention is not limited to the above-described embodiments, and can take various forms. For example, the cathode notch portion 81C is not limited to the shape provided at three locations, and may be a shape provided at one location in the center or a shape provided at only two locations on the left and right. Further, the cathode notch 81C is not limited to a shape extending vertically from the cathode support portion 83, but may be inclined, not limited to a shape cut from the outer periphery, and may be an opening shape.

  Further, the number of capacitor elements stacked is not limited to three, and may be increased or decreased according to the required capacity.

  Further, the cathode external terminal portion 82 may be formed separately from the cathode contact portion 81 and the cathode support portion 83 and welded.

CP ... carbon paste L1 ... ammonium adipate aqueous solution L2 ... raw material solution 1 of conductive polymer raw material solution ... valve metal substrate 2 ... dielectric layer 3 ... conductive polymer layer 5 ... silver electrode layer 6 ... spacer 8 ... Conductive member 9 ... Element bonding material 11 ... Capacitor element 12 ... Al foil 13 ... Counter electrode 50 ... Exterior resin 60 ... Laminate 70 ... Anode conducting material 71 ... Anode contact portion 71C ... Notch portion 72 ... Anode external terminal portion 80 ... Cathode Conductive material 81 ... cathode contact part 81C ... cathode notch part 81C ... notch part 82 ... cathode external terminal part 83 ... cathode support part 101 ... solid electrolytic capacitor

Claims (8)

A multilayer body in which a plurality of capacitor elements each provided with a dielectric layer, a conductive polymer layer, and a cathode layer are laminated on the surface of the valve metal base;
An anode conducting material conducting to the valve metal substrate and a cathode conducting material conducting to the cathode layer,
In a solid electrolytic capacitor in which at least the laminate is coated with an exterior resin,
At least the cathode conducting material has a notch in a contact portion with which the cathode layer contacts,
A solid electrolytic capacitor in which a conductive member that electrically connects the plurality of capacitor elements constituting the multilayer body is provided in the notch.   2. The solid electrolytic capacitor according to claim 1, wherein the capacitor element has a rectangular plate shape, the laminated body has a rectangular parallelepiped shape, and an end surface of the laminated body is in contact with the cathode conductive material.   The solid electrolytic capacitor according to claim 1, wherein the conductive member is made of a conductive paste.   The solid electrolytic capacitor according to claim 1, wherein the conductive member does not overlap the cathode conductive material.   5. The solid electrolytic capacitor according to claim 1, wherein the notch is a portion obtained by bending a part of the cathode conducting material or the anode conducting material. A multilayer body in which a plurality of capacitor elements each provided with a dielectric layer, a conductive polymer layer, and a cathode layer are laminated on the surface of the valve metal base;
An anode conducting material conducting to the valve metal substrate and a cathode conducting material conducting to the cathode layer,
A method for producing a solid electrolytic capacitor in which at least the laminate is coated with an exterior resin,
The cathode conducting material has a notch in a portion where end faces of the capacitor element laminate are close to each other,
Directly stacking and mounting the plurality of capacitor elements on the cathode conducting material;
Applying a conductive member to an end face of the capacitor element laminate mounted on the cathode conducting material;
A method for producing a solid electrolytic capacitor, comprising:   The method for manufacturing a solid electrolytic capacitor according to claim 6, wherein the conductive member is a conductive paste, and the conductive paste is injected by a jet dispenser.   The method for manufacturing a solid electrolytic capacitor according to claim 6 or 7, wherein the notch is formed in the anode conductive material, and the anode portion of the capacitor element is connected to the anode conductive material by laser spot welding.

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