JP2009010067A - Chip type solid electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further achieve a low ESL of a chip type solid electrolytic capacitor used for each kind of electronic equipment. <P>SOLUTION: With a configuration including a cathode terminal 6, where a cathode electrode section 3 of an element laminate 4 in which the cathode electrode section 3 and an anode electrode section 2 are arranged at the center and at both the sides by laminating a planar element 1 having the anode electrode section 2 at different ends at long sides that the rectangular cathode electrode sections 3 oppose, a pair of anode terminals 5 to which the anode electrode section 2 is joined, and a packaging resin 8 covering them, a current path flowing between the anode/cathode electrode sections 2, 3 can be reduced extremely because of cancellation, thus reducing the ESL greatly. Further, with a configuration where the element is made rectangular, the ESL can be reduced further. Also, with a configuration where the anode electrode sections 2 are arranged in alternately and mutually opposing directions for laminating the element 1, the number of the anode electrode sections 2 joined to the anode terminal 5 is halved, thus improving working efficiency and reliability in junction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a chip-type solid electrolytic capacitor in which a conductive polymer is used as a solid electrolyte among capacitors used in various electronic devices and is adapted for surface mounting.

  Along with the increase in frequency of electronic equipment, capacitors that are one of the electronic components have been required to have better impedance characteristics in the high frequency range than before. Various solid electrolytic capacitors using a highly conductive polymer as a solid electrolyte have been studied.

  In recent years, a solid electrolytic capacitor used around a CPU of a personal computer has been strongly demanded to have a small size and a large capacity. Further, not only a low ESR (equivalent series resistance) is reduced in response to a higher frequency but also a noise. There is a strong demand for low ESL (equivalent series inductance) excellent in removal and transient response, and various studies have been made to meet such demand.

  FIGS. 6A and 6B are a perspective view and a bottom view showing the structure of this type of conventional chip-type solid electrolytic capacitor proposed by the present inventors, and FIGS. 7A to 7C are the same. 1 is a perspective view of a cathode lead frame used in a chip-type solid electrolytic capacitor, a perspective view of the anode lead frame, and a perspective view of a state in which the two lead frames are superposed.

  6 and 7, reference numeral 21 denotes a capacitor element. The capacitor element 21 has an insulating property at a predetermined position of an anode body in which a dielectric oxide film is formed on the surface by roughening an aluminum foil which is a valve action metal. A resist portion 21a is provided and separated into an anode electrode portion 21b and a cathode forming portion, and a solid electrolyte layer made of a conductive polymer, a cathode layer made of a carbon layer and a silver paste layer are formed on the dielectric oxide film of the cathode forming portion. The cathode electrode portion 21c is formed by sequentially stacking and forming.

  Reference numeral 22 denotes an anode lead frame. The anode lead frame 22 is provided with an anode joining portion 22b to which the anode electrode portion 21b of the capacitor element 21 is joined at one end of the flat portion 22a, and an anode terminal portion 22c for mounting. A plurality are provided on the lower surface. The anode terminal portion 22c is formed so as to protrude from the flat surface portion 22a to the mounting surface side by bending one base material.

  Reference numeral 23 denotes a cathode lead frame. The cathode lead frame 23 is mounted on and bonded to the cathode electrode portion 21c of the capacitor element 21 and mounted on the flat portion 22a of the anode lead frame 22 via an insulating layer (not shown). A plurality of planar portions 23a and mounting cathode terminal portions 23b are provided on the lower surface. The cathode terminal portion 23b is formed so as to protrude from the flat surface portion 23a to the mounting surface side by bending a single substrate. Reference numeral 23 c denotes a guide wall provided for positioning and fixing the cathode electrode portion 21 c of the capacitor element 21. The insulating layer (not shown) may be formed by printing a polyimide film having a thickness of about 10 μm or a resin.

  Reference numeral 24 denotes an insulating exterior resin that integrally covers the plurality of capacitor elements 21, the anode lead frame 22, and the cathode lead frame 23 with the mounting surfaces of the anode terminal portion 22c and the cathode terminal portion 23b exposed. In (a), in order to make the internal structure easy to understand, the exterior resin 24 is shown in a state removed.

  The conventional chip-type solid electrolytic capacitor configured as described above has a structure in which the anode lead frame 22 is arranged so as to flow in the direction opposite to the direction of the current flowing in the cathode lead frame 23, so Since the currents flowing through each other cancel each other, ESL can be greatly reduced (reference: 270 pH) (Patent Document 1).

  FIG. 8 is a perspective view showing another example of a conventional electrolytic capacitor, FIG. 9 is an exploded perspective view thereof, and in FIGS. 8 and 9, 30 is an electrolytic capacitor. In this configuration, a laminated body 34 including a capacitor element 32 and a capacitor element 33 is mounted on 31.

  The capacitor element 32 has a thin plate-shaped cathode terminal 32a having a rectangular shape in plan view, and an anode terminal 32b is drawn out from one side of the cathode terminal 32a. The anode terminal 32b is the center of the side of the cathode terminal 32a on which the anode terminal 32b is formed. The capacitor element 33 is configured in the same manner.

  And the capacitor | condenser element 32 and the capacitor | condenser element 33 which were comprised in this way are arrange | positioned as shown in FIG. 9, and the laminated body 34 which connected the cathode terminal 32a and the cathode terminal 33a via the electrically conductive adhesive is comprised, The stacked body 34 is mounted on the substrate 31, and the cathode terminal 32 a and the cathode connection portion 31 a provided on the substrate 31 are connected with a conductive adhesive, and the anode terminal 32 b and the anode terminal 33 b of the stacked body 34 are connected to the substrate 31. The anode connecting portion 31b provided is connected by welding or caulking.

By adopting such a configuration, the anode terminal 32b and the anode terminal 33b are prevented from overlapping each other, so that the capacitor element 32 and the capacitor element 33 are laminated on the substrate 31 in spite of being laminated. Since the anode terminal connected to the anode connection part 31b of 31 is substantially one layer, the above welding and caulking can be performed very easily and a good connection can be obtained (patent) Reference 2).
JP 2006-080427 A JP 2005-191466 A

  However, although the conventional chip-type solid electrolytic capacitor has the effect that the ESL can be greatly reduced as compared with the conventional product, it is further improved for the low ESL required at a higher level. There was a problem that it was necessary.

  An object of the present invention is to provide a chip-type solid electrolytic capacitor capable of solving such a conventional problem and realizing further reduction in ESL.

  In order to solve the above-described problems, the present invention provides a plate-like electrode having a rectangular cathode electrode part and a pair of anode electrode parts provided to protrude from different ends on opposite long sides of the cathode electrode part. By laminating a plurality of elements so that the anode electrode portions are alternately arranged in opposite directions, the element laminate in which the cathode electrode portion is arranged in the center and the anode electrode portions are arranged at both ends in the top view, and this element A cathode terminal in which the cathode electrode portion located in the center of the laminate is joined to the upper surface, a pair of anode terminals in which the anode electrode portions located at both ends are joined to the upper surface, and at least a mounting surface of the anode terminal and the cathode terminal Except for the portion, the element laminate and the insulating exterior resin in which the anode terminal and the cathode terminal are integrally coated are used.

  As described above, the chip-type solid electrolytic capacitor according to the present invention has a center of an element laminate in which a plurality of plate-like elements each having an anode electrode portion provided at different ends on opposite long sides of a rectangular cathode electrode portion are laminated. The cathode electrode part is arranged at both ends, and the anode electrode part is arranged at both ends, so that the current path flowing between the anode electrode part and the cathode electrode part arranged close to each other on the same line of the element is extremely shortened and canceled out. In addition to being able to greatly reduce the ESL to be able to match, the ESL can be further reduced by the configuration in which the element has a rectangular shape in which the direction intersecting the direction of current flow is elongated. It is possible to obtain the effect of being able to do so.

  In addition, the configuration in which a plurality of elements are stacked so that the anode electrode portions are alternately arranged in opposite directions can reduce the number of anode electrode portions joined to the anode terminal by half, so that the joining workability The effect that the reliability can be improved is also obtained.

(Embodiment 1)
Hereinafter, the invention described in the first, second, and fourth aspects of the present invention will be described using the first embodiment.

  1A to 1D are a plan view, a front view, a bottom view, and a side view showing a configuration of a chip-type solid electrolytic capacitor according to Embodiment 1 of the present invention, and FIGS. FIG. 3 is a perspective view showing an element used in the chip-type solid electrolytic capacitor, and FIG. 3 is a perspective view showing the elements used in the chip-type solid electrolytic capacitor before the chip-type solid electrolytic capacitor is coated with an exterior resin. FIG. 3 is a bottom view showing a comb terminal used in the chip-type solid electrolytic capacitor.

  1 to 4, reference numeral 1 denotes an element. The element 1 is a dielectric (not shown) on the surface of an anode body made of an aluminum foil having a shape in which a protruding portion is provided at each of different ends on a rectangular opposite long side. After forming the body oxide film layer, an insulating resist portion (not shown) is provided at a predetermined position, and the pair of protrusions are used as anode electrode portions 2 and the remaining portions are separated as cathode forming portions (not shown). The cathode electrode portion 3 is formed by sequentially laminating a solid electrolyte layer made of a conductive polymer, a cathode layer made of a carbon layer and a silver paste layer (all not shown) on the surface of the cathode forming portion, Thus, a pair of anode electrode portions 2 are provided so as to protrude at different ends on the opposite long sides of the rectangular cathode electrode portion 3.

  4 is a stack of a plurality of pieces (in the present embodiment, the number is not limited to six), but the anode electrode portions 2 of the element 1 are alternately arranged in opposite directions. It is an element laminate, in which the cathode electrode part 3 is laminated so that it overlaps at the same position, so that the cathode electrode part 3 is arranged at the center and the anode electrode part 2 is arranged at both ends in a top view. In addition, the cathode electrode portions 3 are joined to each other via a conductive adhesive (not shown).

  Reference numeral 5 denotes a pair of anode terminals in which the anode electrode portion 2 of the element laminate 4 thus configured is joined to the upper surface. The plurality of anode electrode portions 2 are overlapped on the upper surface of the anode terminal 5 so as to be folded. The anode terminal 5 and the anode electrode part 2 are joined by performing resistance welding (welding marks 5b) so that the anode terminals 5 are bent at both ends and the anode electrode parts 2 are bundled together. It is what I did. 5a is a step provided at both ends on the lower surface side which is the mounting surface of the anode terminal 5, and this step 5a is covered with an exterior resin 8 which will be described later and becomes an insulating portion.

  Similarly to the above, 6 is a cathode terminal in which the cathode electrode portion 3 of the element laminate 4 is bonded to the upper surface, and the cathode electrode portion 3 of the element laminate 4 is placed on the upper surface of the cathode terminal 6 to conduct conductive bonding. It is made to join through an agent. Reference numeral 6a denotes a step portion provided in the center on the lower surface side which is the mounting surface of the cathode terminal 6, and this step portion 6a is covered with an exterior resin 8 which will be described later to become an insulating portion. Reference numeral 6b denotes a bent portion in which both ends of the cathode terminal 6 are bent upward, and a conductive silver paste 7 is interposed between the inner surface of the bent portion 6b and the cathode electrode portion 3 of the element laminate 4 for the purpose of reducing ESR. It is what is filled.

  Reference numeral 8 denotes an insulating exterior resin integrally covering the element laminate 4 to which the anode terminal 5 and the cathode terminal 6 are joined. The exterior resin 8 is provided on the mounting surface of the anode terminal 5 and the cathode terminal 6. Since the stepped portions 5a and 6a are filled, respectively, a four-terminal structure in which the anode terminal 5 and the cathode terminal 6 are arranged in pairs on opposite sides on the mounting surface after being covered with the exterior resin 8 respectively. The chip type solid electrolytic capacitor is constituted.

  Further, the comb terminal 9 shown in FIG. 4 forms the anode terminal 5 and the cathode terminal 6 at predetermined positions by punching one flat base material, and the anode terminal 5 and the cathode terminal 6 are formed on the anode terminal 5 and the cathode terminal 6. After the element laminate 4 is joined, unnecessary portions are cut and finally covered with the exterior resin 8.

  The thus configured chip-type solid electrolytic capacitor according to the present embodiment includes a plurality of plate-like elements 1 each having an anode electrode portion 2 provided at different ends on opposite long sides of a rectangular cathode electrode portion 3. The anode electrode part 2 and the cathode electrode part 3 arranged at close positions on the same line of the element 1 by the configuration in which the cathode electrode part 3 is arranged at the center of the laminated element laminate 4 and the anode electrode part 2 is arranged at both ends. Since the current path flowing between them can be made extremely short and can cancel each other, not only can the ESL be greatly reduced, but also the direction in which the element 1 intersects the direction in which the current flows The lengthened rectangular configuration provides a special effect that the ESL can be further reduced. The measured ESL of this chip-type solid electrolytic capacitor is 50.4p. It showed a low value of, in which it is possible to greatly reduce the ESL compared conventional and (270pH).

  In addition, since the plurality of elements 1 are stacked so that the anode electrode portions 2 are alternately arranged in opposite directions, the number of anode electrode portions 2 joined to the anode terminal 5 can be halved. The effect that the workability | operativity and reliability of joining can be improved is also acquired.

(Embodiment 2)
The second aspect of the present invention will be described below with reference to the second embodiment.

  This embodiment is different in that an anode / cathode lead frame is disposed between the element laminate of the chip-type solid electrolytic capacitor described in the first embodiment with reference to FIGS. 1 to 4 and the anode / cathode terminal. Since the configuration other than this is the same as that of the first embodiment, the same reference numerals are given to the same parts and the detailed description thereof is omitted, and only different parts will be described below with reference to the drawings. .

  FIGS. 5A and 5B are a perspective view from the top surface side and a perspective view from the bottom surface side before coating with the exterior resin showing the configuration of the chip-type solid electrolytic capacitor according to the second embodiment of the present invention. In FIG. 5, reference numeral 10 denotes a pair of anode lead frames in which the anode electrode part 2 of the element laminate 4 is bonded to the upper surface, and a plurality of anode electrode parts 2 are overlapped on the upper surface of the anode lead frame 10 so as to be bent. Then, the anode lead frame 10 and the anode electrode part 2 are joined by performing resistance welding (welding marks are not shown) by bending both ends of the anode lead frame 10 and bundling the anode electrode parts 2 together. It is what you do.

  Similarly to the above, 11 is a cathode lead frame in which the cathode electrode portion 3 of the element laminate 4 is bonded to the upper surface. The cathode electrode portion 3 of the element laminate 4 is placed on the upper surface of the cathode lead frame 11 to conduct It is made to join through an adhesive. Reference numeral 11a denotes a bent portion in which both ends of the cathode lead frame 11 are bent upward. The conductive silver paste 7 is provided between the inner surface of the bent portion 11a and the cathode electrode portion 3 of the element laminate 4 for the purpose of reducing ESR. Is filled.

  Reference numeral 12 denotes a pair of anode terminals, and 13 denotes a cathode terminal. The anode lead frame 10 and the cathode lead frame 11 to which the element laminate 4 is joined are joined to the upper surface, respectively. It is performed by means such as welding. The steps 12a are provided at both ends on the lower surface side, which is the mounting surface of the anode terminal 12, and the steps 13a are provided at the center on the lower surface side, which is the mounting surface of the cathode terminal 13. This is the same as in the first embodiment.

  The chip-type solid electrolytic capacitor according to the present embodiment configured as described above has an effect obtained by the chip-type solid electrolytic capacitor according to the first embodiment, and in addition, between the element laminate 4 and the anode / cathode terminals 5 and 6. With the configuration in which the anode / cathode lead frames 10 and 11 are disposed, the element laminate 4 can be assembled alone, and therefore, the workability can be improved.

  When the ESL of the chip-type solid electrolytic capacitor according to this embodiment was measured, it showed a low value of 52.8 pH.

  The chip-type solid electrolytic capacitor according to the present invention has an effect that the ESL can be greatly reduced, and is particularly useful as a field where high frequency response is required.

(A) The top view which showed the structure of the chip-type solid electrolytic capacitor by Embodiment 1 of this invention, (b) The front view, (c) The bottom view, (d) The side view (A) Perspective view from the top surface before coating the chip-type solid electrolytic capacitor with an exterior resin, (b) Perspective view from the bottom surface side The perspective view which showed the element used for the chip type solid electrolytic capacitor Bottom view showing comb terminals used in the same chip-type solid electrolytic capacitor (A) The perspective view from the upper surface side before coat | covering with the exterior resin which showed the structure of the chip-type solid electrolytic capacitor by Embodiment 2 of this invention, (b) The perspective view from the same bottom face side (A) The perspective view which showed the structure of the conventional chip-type solid electrolytic capacitor, (b) The bottom view (A) A perspective view of a cathode lead frame used in the chip-type solid electrolytic capacitor, (b) a perspective view of the anode lead frame, and (c) a perspective view in a state where the lead frames are overlapped. The perspective view which showed the other example of the conventional electrolytic capacitor Exploded perspective view

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Element 2 Anode electrode part 3 Cathode electrode part 4 Element laminated body 5, 12 Anode terminal 5a, 6a, 12a, 13a Step part 5b Weld mark 6, 13 Cathode terminal 6b, 11a Bending part 7 Conductive silver paste 8 Exterior resin 9 Com terminal 10 Anode lead frame 11 Cathode lead frame

Claims (4)

Direction in which the anode electrode portion alternately opposes a plate-like element having a rectangular cathode electrode portion and a pair of anode electrode portions protruding at different ends on opposite long sides of the cathode electrode portion. By laminating a plurality of sheets so as to be arranged in a top view, an element laminated body in which a cathode electrode part is arranged at the center and an anode electrode part is arranged at both ends, and a cathode electrode part located at the center of the element laminated body Except for the cathode terminal bonded to the upper surface, the pair of anode terminals bonded to the upper surface of the anode electrode portions located at both ends thereof, and the element laminate and the anode terminal except for the anode terminal and at least the mounting surface portion of the cathode terminal. Chip-type solid electrolytic capacitor made of an insulating exterior resin that covers the cathode and cathode terminals together. A width dimension of a pair of anode electrode portions protruding from different ends on opposite long sides of the cathode electrode portion constituting the element is ½ or less of the length of the long side of the cathode electrode portion. Item 2. The chip-type solid electrolytic capacitor according to Item 1. A cathode lead frame that joins the cathode electrode portion located at the center of the element stack to the upper surface and an anode lead frame that joins the anode electrode portions located at both ends to the upper surface are provided. 2. The chip-type solid electrolytic capacitor according to claim 1, wherein the chip-type solid electrolytic capacitor is joined to a terminal and a cathode terminal, respectively. 2. The chip-type solid electrolytic capacitor according to claim 1, wherein an insulating portion is provided at both ends of the mounting surface of the anode terminal and at the center of the mounting surface of the cathode terminal, thereby forming a four-terminal structure as viewed from the bottom.

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