JP4613669B2 - Solid electrolytic capacitor - Google Patents

Description

The present invention is in the capacitors that are used in various electronic devices, in particular, a conductive polymer in which relates to a solid electrolytic capacitor using a solid electrolyte.

  Along with the higher frequency of electronic devices, capacitors that are one of the electronic components are also required to have better impedance characteristics in the high frequency range than before, and high electrical conductivity is required to meet these requirements. Various solid electrolytic capacitors using a conductive polymer as a solid electrolyte have been studied.

  FIG. 6 is a sectional view showing the structure of this type of conventional solid electrolytic capacitor, FIG. 7 is a perspective view thereof, and FIG. 8 is a partially cutaway perspective view showing the structure of a capacitor element used in the solid electrolytic capacitor. 6 to 8, reference numeral 20 denotes a capacitor element. The capacitor element 20 is formed by forming a dielectric oxide film layer on the surface of an anode body 21 made of an aluminum foil which is a valve metal, and then insulating resist portions. 22 is separated into an anode portion 23 and a cathode portion 24, and a solid electrolyte layer 25 made of a conductive polymer and a cathode layer 26 made of carbon and silver paste are sequentially formed on the surface of the dielectric oxide film layer of the cathode portion 24. It is configured by stacking.

  27 is an anode terminal, 28 is a cathode terminal, 28a is a guide part formed by bending a part of the connection surface of the cathode terminal 28, and the anode part 23 of the capacitor element 20 is connected to the connection surface of the anode terminal 27. Similarly, the cathode portion 24 is mounted on the connecting surface of the cathode terminal 28, the anode portion 23 of the capacitor element 20 is joined by resistance welding by bending the connecting portion 27a of the connecting surface of the anode terminal 27, and the cathode portion 24 is joined to the cathode. It is joined to the connection surface of the terminal 28 via a conductive silver paste (not shown).

  Reference numeral 29 denotes an insulating exterior resin that covers the capacitor element 20 in a state where parts of the anode terminal 27 and the cathode terminal 28 to which the capacitor element 20 is bonded are exposed on the outer surface. The exposed anode terminal 27 and cathode terminal 28 were each bent from the side surface to the bottom surface along the exterior resin 29 to constitute an external terminal, thereby constituting a surface mount type solid electrolytic capacitor.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2000-340463 A

  However, in the above-described conventional solid electrolytic capacitor, since the distance from the contact surface (the anode portion 23 and the cathode portion 24) between the anode terminal 27 and the capacitor element 20 of the cathode terminal 28 to the mounting surface is long, ESL (equivalent series inductance) characteristics are obtained. In recent years, there has been a strong demand for smaller and larger electrolytic capacitors used around CPUs in personal computers, and only low ESR (equivalent series resistance) is required for higher frequencies. In other words, it has a problem that it cannot be employed in a situation where noise eliminability and transient response are excellent and low ESL is required.

An object of the present invention is to solve such a conventional problem and to provide a solid electrolytic capacitor capable of achieving low ESL by shortening a drawing distance from a capacitor element to a terminal. .

  In order to achieve the above object, the present invention joins a plate-like capacitor element having an anode part and a cathode part on an anode frame frame, and joins the anode frame and the cathode frame on the anode terminal and the cathode terminal, respectively. In the solid electrolytic capacitor in which the lower surfaces of the mounting surfaces of the anode terminal and the cathode terminal are exposed and the capacitor element is covered with the exterior resin, the above-described direction that intersects the direction connecting the anode terminal and the cathode terminal At both ends of the anode terminal, a stepped step is formed upward from the lower surface of the anode terminal to provide a joining surface joined to the anode frame, and at the center of the cathode terminal upward from the lower surface of the cathode terminal. A joint surface to be joined to the raised cathode frame is provided, and further, the anode terminal and the lower surface of the cathode terminal at a portion where the cathode terminal and the lower surface of the anode terminal are close to each other A shielding portion extending upward from the first portion toward the other side is provided on each of the anode terminal and the cathode terminal, and the respective joint surfaces and shielding portions provided on the anode terminal and the cathode terminal are covered with the exterior resin. It is composed.

  As described above, according to the present invention, the anode part of the capacitor element is joined to the anode frame, and the anode frame is joined to the joining surface formed with the stepped step from the lower surface of both ends of the anode terminal, and the capacitor The cathode part of the element is joined to the cathode frame, and the cathode frame joined to the joining surface raised from the lower surface of the cathode terminal to the center part, and the lower surface that becomes the mounting surface of the anode terminal and the cathode terminal are brought closer to each other. With this configuration, the lead-out distance from the anode part and the cathode part of the capacitor element to the anode terminal and the mounting surface of the cathode terminal is short, and the anode terminal and the cathode terminal come close to form an electric circuit with the outside. The effect of decreasing is obtained.

  With the above configuration, the ESR can be reduced because the lead-out distance from the capacitor element to the mounting surface of the anode terminal and the cathode terminal is shortened at the same time.

  In addition, the structure provided with shielding portions provided on the anode terminal and the cathode terminal respectively suppresses oxygen and moisture entering from the exterior resin from reaching the capacitor element, greatly reducing degradation of ESR characteristics and leakage current characteristics. The effect which can be done is acquired.

  Further, by connecting the cathode frame and the joint surface raised from the lower surface of the cathode terminal to the center, and covering the joint surface with an exterior resin, the joint strength between the cathode terminal and the cathode frame can be stabilized. Is obtained.

(Embodiment)
Hereinafter, with reference to the embodiment, it will be described with the present invention.

  1A to 1D are a side sectional view, a sectional view taken along a line AA, a sectional view taken along a line BB, and a bottom view showing a configuration of a solid electrolytic capacitor according to an embodiment of the present invention. FIG. 4 is a partially cutaway perspective view showing the configuration of a capacitor element used in an electrolytic capacitor, FIGS. 3A to 3C are a plan view, a side view, and a front view showing the configuration of the capacitor element unit, FIG. FIG. 4 is a perspective view of a main part showing a configuration of an anode terminal and a cathode terminal used in the solid electrolytic capacitor, and a cross-sectional view of a main part of a bottom end of the anode terminal and the cathode terminal used in the solid electrolytic capacitor in FIG. is there.

  1 to 5, reference numeral 1 denotes a capacitor element. The capacitor element 1 has an insulating resist portion after a dielectric oxide film layer (not shown) is formed on the surface of an anode body 2 made of an aluminum foil which is a valve metal. 3 is separated into an anode portion 4 and a cathode portion 5, and a solid electrolyte layer 6 made of a conductive polymer and a cathode layer 7 made of carbon and silver paste are sequentially laminated on the surface of the cathode portion 5. It is configured.

  Reference numeral 8 denotes an anode frame. The anode part 4 is placed in a state where a plurality of the capacitor elements 1 (5 sheets in the present embodiment) are stacked on the anode frame 8, and the guide parts 8a at both ends are bent. The anode part 4 is encased and the anode part 4 is integrally joined to the anode frame 8 by performing laser welding at the joint part 8b.

  Reference numeral 9 denotes a cathode frame. A plurality of the capacitor elements 1 are stacked on the cathode frame 9 and the cathode portion 5 is placed via a conductive adhesive (not shown). The cathode portion 5 is integrally joined to the cathode frame 9 by positioning and fixing by the portion 9b.

  A structure in which a plurality of capacitor elements 1 are stacked and integrated by the anode frame 8 and the cathode frame 9 is shown in FIG. 3 and is hereinafter referred to as a capacitor element unit.

  Reference numeral 10 denotes an anode terminal. The anode terminal 10 has a staircase that goes upward from the lower surface 13 of the anode terminal to both ends of the anode terminal 10 that is on the direction intersecting the direction connecting the anode terminal 10 and the cathode terminal 11 described later. A planar joining surface 10a to be joined to the anode frame 8 having a stepped shape and a shielding portion 10b extending obliquely upward from the end of the lower surface 13 of the anode terminal toward the cathode terminal 11; .

  These are integrally formed by punching and bending a sheet-like base material made of a copper alloy having a thickness of 0.1 mm, and mounting the anode frame 8 of the capacitor element unit on the joint surface 10a of the anode terminal 10. And joining by performing laser welding at the joint 10c.

  Reference numeral 10d denotes a protrusion that extends from one end of the lower surface of the anode terminal 10 so as to protrude upward from an exterior resin 12 described later. The protrusion 10d is bent upward along the side surface of the exterior resin 12. This facilitates the formation of solder fillets during board mounting.

  Reference numeral 11 denotes a cathode terminal. To the cathode terminal 11, the lower surface 14 of the cathode terminal is placed as close as possible to the lower surface 13 of the anode terminal, and the entire width of the cathode terminal 11 is placed at the center of the cathode terminal 11. A joining surface 11a joined to the cathode frame 9 protruding upward from the lower surface 14 and a shielding portion 11b extending obliquely upward from the end of the lower surface 14 of the cathode terminal toward the anode terminal 10 are provided.

  The lower surfaces 13 and 14 of the anode terminal and the cathode terminal serve as mounting surfaces.

  These are integrally formed by punching and bending a plate-like base material made of a single copper alloy. The cathode frame 9 of the capacitor element unit is placed on the joining surface 11a of the cathode terminal 11 and joined. The surface 11a is joined through a conductive adhesive (not shown).

  Reference numeral 11c denotes a protruding portion obtained by extending one end of the lower surface of the cathode terminal 11 so as to protrude outward from an exterior resin 12 described later. The protruding portion 11c is bent upward along the side surface of the exterior resin 12. This facilitates the formation of solder fillets during board mounting.

  Reference numeral 12 denotes an insulating exterior resin in which the capacitor element unit is integrally covered with the anode terminals and the lower surfaces 13 and 14 of the cathode terminals exposed. In this embodiment, an epoxy resin is used. .

  The joining surfaces 10a and 11a and the shielding portions 10b and 11b provided on the anode terminal 10 and the cathode terminal 11 are all covered with the exterior resin 12, respectively, and are configured not to be exposed to the exterior. It is what.

  Also, the anode terminal 10 and the cathode terminal 11 configured as described above are provided in pairs at a predetermined interval on a hoop-shaped base material made of a copper alloy, and a plurality of such anode terminals 10 and cathode terminals 11 are continuously provided. A capacitor element unit is mounted on and joined to the terminal 10 and the cathode terminal 11, and is integrally covered with the exterior resin 12, and then separated from the base material into individual pieces.

  In the solid electrolytic capacitor according to the present embodiment configured as described above, the anode portion 4 and the cathode portion 5 of the capacitor element 1 are taken out from the anode terminal 10 and the cathode terminal 11 formed in a substantially flat plate shape. Accordingly, the lead-out distance from the capacitor element 1 to each terminal is shortened as much as possible, and further, the path between the anode terminal 10 and the cathode terminal 11 is made by bringing the lower surface of the cathode terminal 11 as close as possible to the lower surface of the anode terminal 10. With the shortest distance configuration, the ESR characteristics are excellent and low ESL can be realized.

  In particular, regarding the ESL characteristics, the solid electrolytic capacitor according to the present embodiment was as low as 530 pH, and a result that was about 1/3 compared with 1500 pH of the conventional product could be obtained.

  Further, shielding portions 10b and 11b extending obliquely upward from the lower surface end surfaces of the anode terminal 10 and the cathode terminal 11 toward the mating terminal direction are provided on the anode terminal 10 and the cathode terminal 11, respectively, and the shielding portions 10b and 11b are provided. With the structure coated with the exterior resin 12, respectively, oxygen and moisture entering from the exterior resin 12 and the interface between the exterior resin 12 and the anode terminal 10 and the cathode terminal 11 are shielded by the shielding portions 10b and 11b made of plate-like metal. Suppressing the capacitor element 1 and degrading the performance of the ESR characteristic and leakage current characteristic can be greatly reduced.

  The exterior resin 12 sufficiently wraps around the back surface of the joining surface 11a raised from the lower surface 14 of the cathode terminal, and the joining strength between the cathode terminal 11 and the cathode frame 9 at the joining surface 11a can be stabilized.

  Similarly, an exterior resin is formed around the joint surface 10a to which the anode frame 8 of the anode terminal 10 is joined, and the joining strength between the anode terminal 10 and the anode frame 8 at the joint surface 10a can be stabilized.

  Further, joining surfaces 10a and 11a are respectively provided on the anode terminal 10 and the cathode terminal 11, and the anode frame 8 and the cathode frame 9 are joined to each other by laser welding and a conductive adhesive at the joining surfaces 10a and 11a. 10a and 11a are each covered with the exterior resin 12, so that the joint traces of the joints are covered with the exterior resin 12, so that the appearance is not only beautiful, but also the mounting traces are generated due to the weld traces. This eliminates the fear of causing defects, and can greatly contribute to the improvement of reliability.

  In the present embodiment, the anode body 2 constituting the capacitor element 1 has been described by taking an example of a structure made of an aluminum foil. However, the present invention is not limited to this, and a tantalum or niobium foil, A sintered body or a combination of these materials may be used.

  In the present embodiment, the projecting portions 10d and 11c provided by extending one end of a part of the lower surfaces 13 and 14 of the anode terminal and / or the cathode terminal so as to project outward from the exterior resin 12 are provided on the exterior. Although the configuration in which the resin 12 is bent upward along the side surface of the resin 12 has been described, by providing the exterior resin 12 with recesses into which the protruding portions 10d and 11c that are bent upward along the side surface of the exterior resin 12 are fitted, the size is further reduced. It becomes possible to plan.

  Further, in FIG. 5, 10f, 11f, 10h, and 11h denote end portions connected to the joining surfaces 10a and 11a, the anode terminals forming the shielding portions 10b and 11b, and the lower surfaces 13 and 14 of the cathode terminals, The connecting surfaces 10a and 11a and the shielding portions 10b and 11b are bent upward by crushing them using a press mold so that the thickness of the taper portion 15 to be tied is smaller than the thickness of the plate-like base material of the lower surfaces 13 and 14. By forming, the end portions 10f, 11f, 10h, and 11h may be configured to have a small bending radius R.

  The bending process is preferably an offset bending process.

  When the bending radius R is smaller than 0.001 mm, it is difficult to process the press mold, and when the bending radius R is larger than 0.05 mm, the wraparound length of the exterior resin 12 is increased. ~ 0.05 mm is desirable.

  By providing a small bend radius at the bottom surface end that becomes the mounting surface, the wraparound length of the exterior resin 12 is suppressed to 0.05 mm or less from the bottom surface end, and the mounting surface length can be secured and excellent mounting Sex is obtained.

The solid electrolytic capacitor according to the present invention has an excellent ESR characteristic and an ESL characteristic due to a configuration in which the lead-out distance from the capacitor element to the terminal is as short as possible and the lower surface of the cathode terminal is as close as possible to the lower surface of the anode terminal. Moreover, it is possible to greatly reduce the deterioration of performance due to oxygen and moisture entering from the interface between the exterior resin and the terminal by the shielding portions provided on the anode terminal and the cathode terminal, respectively, and the exterior resin. In addition, it has a special effect that it can stably provide a high-performance, high-reliability solid electrolytic capacitor, and is particularly used around a CPU of a personal computer. It is useful as a capacitor.

(A) is a side sectional view showing a configuration of a solid electrolytic capacitor according to an embodiment of the present invention, (b) is a sectional view taken along the line AA, (c) is a sectional view taken along the line BB, and (d) is a sectional view taken along the same line. Bottom view Partially cutaway perspective view showing the configuration of a capacitor element used in the solid electrolytic capacitor (A) is the top view which showed the structure of the capacitor | condenser element unit, (b) is the side view, (c) is the front view The principal part perspective view which showed the structure of the anode terminal and cathode terminal which are used for the solid electrolytic capacitor Cross-sectional view of the main part of the bottom end of the anode and cathode terminals used in the solid electrolytic capacitor Sectional view showing the structure of a conventional solid electrolytic capacitor Same perspective view Partially cutaway perspective view showing a capacitor element used in the solid electrolytic capacitor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Anode body 3 Resist part 4 Anode part 5 Cathode part 6 Solid electrolyte layer 7 Cathode layer 8 Anode frame 8a, 9a, 9b Guide part 8b, 10c Joint part 9 Cathode frame 10 Anode terminal 10a, 11a Joint surface 10b, 11b Shielding portion 10d, 11c Projection portion 10f, 10h, 11f, 11h End portion 11 Cathode terminal 12 Exterior resin 13 Lower surface of anode terminal 14 Lower surface of cathode terminal 15 Tapered portion

Claims (6)

A plate-like capacitor element having an anode part and a cathode part is joined to an anode frame and a cathode frame, and the anode frame and the cathode frame are joined to an anode terminal and a cathode terminal, respectively. in the solid electrolytic capacitor of the capacitor element to expose coated with an exterior resin bottom surface of each of the, at both ends of the anode terminal in the upward direction intersecting the direction connecting the anode terminal and the cathode terminal, the anode from the lower surface of the terminal upward together to form a staircase-like steps provided joint surface joined to the anode frame and the cathode frame the raised from the lower surface to the upper side of the cathode terminal in the center portion of the cathode terminal the bonding surface to be bonded is provided, further, the lower surface end portion of said anode terminal and said cathode terminal portion the lower surface of the anode terminal and the cathode terminal is close A shielding portion that extends upward toward the Luo mating respectively provided on the cathode terminal and the anode terminal, and covering the shielding portion and the anode terminal and the said bonding surface of each provided on the cathode terminal to said exterior resin Solid electrolytic capacitor made to be. The anode terminal and the cathode terminal, the solid electrolytic capacitor according to claim 1 which is formed by bending by punching a plate-shaped base material. The joint surface and / or the shielding portion, wherein the lower surface upwardly is formed by bending a plate-shaped base material, the bending processed the joint surface of the anode terminal and / or the cathode terminal, wherein the anode terminal forming the shielding portion, the solid electrolytic capacitor according to claim 1, characterized in that it has a bending radius end small coupling to the lower surface of the cathode terminal. The capacitor element, the surface is roughened and separated into the cathode portion and the anode portion is provided an insulating portion in a predetermined position of the anode body made of a valve metal having a dielectric oxide film layer, the cathode portions 2. The solid electrolytic capacitor according to claim 1, wherein the solid electrolytic capacitor is formed by sequentially laminating a solid electrolyte layer made of a conductive polymer and a cathode layer on the dielectric oxide film layer. Claims wherein the anode terminal and / or at least a portion of said lower surface of said cathode terminal, wherein extending from the packaging resin to protrude outwardly bent upward along the extended portion on a side surface of the exterior resin Item 10. A solid electrolytic capacitor according to Item 1. The anode terminal and / or the solid electrolytic capacitor according to claim 5, at least a part of writing fits the recess of the portion bent upward along the side surface of the exterior resin provided on the exterior resin of the cathode terminal.

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