JP2009238929A - Solid electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid electrolytic capacitor capable of reducing the amount of adhesive arranged between adjacent capacitor elements and increasing the forming pressure of a resin sealing member. <P>SOLUTION: In the solid electrolytic capacitor 1, the insulating adhesive 41 arranged between adjacent capacitor elements 2 is extended along the edge of the capacitor elements 2 facing the resin sealing member 5, thus preventing the penetration of the resin sealing member 5 into an area between the adjacent capacitor elements 2 by the insulating adhesive 41. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solid electrolytic capacitor.

As a conventional solid electrolytic capacitor, a substrate, a capacitor element laminated on the substrate, a conductive adhesive disposed between adjacent capacitor elements, and a resin disposed on the substrate so as to cover the capacitor element What is provided with the sealing member is known (for example, refer patent document 1).
JP 2002-319522 A

  By the way, in the resin-encapsulated solid electrolytic capacitor as described above, while reducing the amount of the conductive adhesive in order to reduce the cost, a resin is used to improve the durability of the resin-encapsulated member. When the molding pressure of the sealing member is increased, the resin sealing member enters between adjacent capacitor elements, and as a result, a leakage current may be generated.

  Therefore, the present invention has been made in view of such circumstances, and can reduce the amount of adhesive disposed between adjacent capacitor elements, and further increase the molding pressure of the resin sealing member. An object of the present invention is to provide a solid electrolytic capacitor that can be used.

  In order to achieve the above object, a solid electrolytic capacitor according to the present invention includes a first conductor layer, a dielectric layer formed on both sides of the first conductor layer, and a second layer formed outside the dielectric layer. A plurality of stacked capacitor elements, an adhesive disposed between adjacent capacitor elements, and a resin sealing member covering the capacitor elements, and the adhesive is at least resin-sealed The capacitor element is arranged so as to extend along an outer edge portion of the capacitor element facing the member.

  In this solid electrolytic capacitor, the adhesive disposed between adjacent capacitor elements extends at least along the outer edge portion of the capacitor element facing the resin sealing member. Thus, the adhesive prevents the resin sealing member from entering between adjacent capacitor elements. Therefore, according to this solid electrolytic capacitor, the amount of the adhesive disposed between the adjacent capacitor elements can be reduced, and the molding pressure of the resin sealing member can be increased.

  In the solid electrolytic capacitor according to the present invention, the adhesive is preferably arranged in a ring shape, and more preferably further arranged in the inner portion of the capacitor element. In these cases, the bonding strength between adjacent capacitor elements can be improved.

  In the solid electrolytic capacitor according to the present invention, it is preferable that the adhesive is an insulating adhesive, and the second conductor layer is electrically connected to each other by a conductive adhesive at an end thereof. When an insulating adhesive is used as the adhesive, the interval between adjacent capacitor elements can be reduced. Thereby, since the entrance of the resin sealing member between adjacent capacitor elements is more reliably prevented, the molding pressure of the resin sealing member can be further increased.

  In the solid electrolytic capacitor according to the present invention, the capacitor element has a resist layer that separates the outer edge portion of the second conductor layer from the first conductor layer, and the adhesive is provided between the adjacent capacitor elements. It is preferable that the capacitor element resist layer be disposed so as to have a thickness that separates the resist layer from the other capacitor element. In this case, even if the thickness of the resist layer varies, the adhesive surely adheres to each of the adjacent capacitor elements, so that sufficient bonding strength between the adjacent capacitor elements can be obtained.

  According to the present invention, the amount of adhesive disposed between adjacent capacitor elements can be reduced, and the molding pressure of the resin sealing member can be increased.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same or an equivalent part, and the overlapping description is abbreviate | omitted.

  FIG. 1 is a longitudinal sectional view of an embodiment of a solid electrolytic capacitor according to the present invention, and FIG. 2 is an exploded perspective view around a conductive member of the solid electrolytic capacitor of FIG. As shown in FIGS. 1 and 2, the solid electrolytic capacitor 1 includes a capacitor element laminate 3 in which a plurality of capacitor elements 2 (here, four layers) are laminated. The capacitor element laminate 3 is disposed on one surface of the printed circuit board 4 and is sealed with a resin sealing member 5.

  3 is a longitudinal sectional view of the capacitor element of the solid electrolytic capacitor of FIG. As shown in FIG. 3, the capacitor element 2 has a rectangular thin plate (or rectangular foil shape) anode layer (first conductor layer) 6 made of aluminum. The surface of the anode layer 6 is roughened to increase the surface area and is porous. Dielectric layers 7 made of aluminum oxide are formed on the surfaces on both sides of the anode layer 6 by chemical conversion treatment. In the chemical conversion treatment, for example, a predetermined voltage is applied in a state where the anode layer 6 is immersed in an aqueous solution of ammonium adipate to cause anodization. Note that one end 6 b in the longitudinal direction of the anode layer 6 is narrower than the main body 6 a of the anode layer 6.

  The resist layer is interposed via the dielectric layer 7 on the surfaces on both sides of the outer edge portion on the end portion 6b side of the main body portion 6a of the anode layer 6 so as to extend along the direction orthogonal to the longitudinal direction of the anode layer 6. 8 is formed (see FIG. 2). The resist layer 8 is formed, for example, by applying an epoxy resin or the like by a screen printing method or the like. Further, a cathode layer (second conductor layer) 9 including a solid polymer electrolyte layer 11, a graphite paste layer 12 and a silver paste layer 13 is formed on the outer surface of the dielectric layer 7 in the main body portion 6 a of the anode layer 6. It is integrally formed through an end surface portion of the main body portion 6a (here, a portion corresponding to the other end portion 6c in the longitudinal direction of the anode layer 6). The resist layer 8 electrically isolates the anode layer 6 and the cathode layer 9 by separating the outer edge portion of the cathode layer 9 from the anode layer 6.

  The solid polymer electrolyte layer 11 is formed on the outer surface of the dielectric layer 7 in a state where it enters a fine hole formed by roughening the anode layer 6. The solid polymer electrolyte layer 11 is formed, for example, by impregnating the anode layer 6 on which the dielectric layer 7 is formed with a polymerization solution to cause chemical oxidative polymerization. The graphite paste layer 12 is formed on the outer surface of the solid polymer electrolyte layer 11, and the silver paste layer 13 is formed on the outer surface of the graphite paste layer 12. The graphite paste layer 12 and the silver paste layer 13 are formed by, for example, an immersion method (dip method). In the resist layer 8, when the anode layer 6 on which the dielectric layer 7 is formed is immersed in the polymerization solution, the polymerization solution enters the end 6b side of the anode layer 6 by capillary action on the porous surface. It has a function to prevent this.

  As shown in FIGS. 1 and 2, the capacitor element 2 is laminated by adhering cathode layers 9 facing each other with an insulating adhesive (adhesive) 41 at a predetermined interval. Then, the cathode layer 9 of the capacitor element 2 located on the outermost layer on the printed circuit board 4 side in the capacitor element laminated body 3 is connected to the wiring electrode 16 formed on one surface of the printed circuit board 4 and the conductive adhesive 14. Is glued by. The conductive adhesive 14 extends along a portion corresponding to the end portion 6 c of the anode layer 6, and electrically connects the cathode layers 9 of the capacitor elements 2 to each other at the end portions. The wiring electrode 16 is connected to the terminal electrode 18 formed on the other surface of the substrate 15 through the through hole 17. That is, the terminal electrode 18 is electrically connected to the cathode layer 9 of each capacitor element 2.

  One end face in the longitudinal direction of the anode layer 6 of each capacitor element 2 (that is, one end face of the end portion 6b in the longitudinal direction of the anode layer 6) is connected to the conductive member 19 by laser welding. The conductive member 19 has a main body 19 a that is erected on the printed circuit board 4 and to which one end face of the anode layer 6 is connected. A base end portion 19b extending inward (that is, the capacitor element 2 side) is provided at an end portion of the main body portion 19a on the printed circuit board 4 side. A distal end portion 19c is provided. The main body 19 a and the base end 19 b have the same width as the main body 6 a of the anode layer 6, and the distal end 19 c has the same width as the end 6 b of the anode layer 6. In addition, the main-body part 19a, the base end part 19b, and the front-end | tip part 19c are formed by bending the plate-shaped member which consists of iron, nickel, copper, or these alloys etc., for example.

  The base end portion 19b of the conductive member 19 is connected to the wiring electrode 21 formed on one surface of the substrate 15 in the printed circuit board 4 by laser welding. The wiring electrode 21 is connected to the terminal electrode 23 formed on the other surface of the substrate 15 through the through hole 22. That is, the terminal electrode 23 is electrically connected to the anode layer 6 of each capacitor element 2. The connection between the base end portion 19b and the wiring electrode 21 by laser welding is that the width of the end portion 19c and the end portion 6b of the anode layer 6 is narrower than the width of the base end portion 19b and the wiring electrode 21. This is performed by irradiating laser light along the stacking direction of the capacitor element 2 on both sides of 19c and the end 6b of the anode layer 6 (see FIG. 2).

  FIG. 4 is a plan view of the capacitor element of the solid electrolytic capacitor of FIG. As shown in FIG. 4, the insulating adhesive 41 is arranged in a rectangular ring shape between the cathode layers 9 of the adjacent capacitor elements 2. The insulating adhesive 41 is an outer edge portion 2a of the capacitor element 2 facing the resin sealing member 5 disposed on the printed circuit board 4 so as to cover the capacitor element laminate 3 (here, orthogonal to the longitudinal direction of the capacitor element 2). Extending along the outer edge portion facing each other in the direction. As shown in FIG. 1, the insulating adhesive 41 is disposed between adjacent capacitor elements 2 so as to have a thickness that separates the resist layer 8 of one capacitor element 2 from the other capacitor element 2. ing.

  As described above, in the solid electrolytic capacitor 1, the insulating adhesive 41 disposed between the adjacent capacitor elements 2 extends along the outer edge portion 2 a of the capacitor element 2 facing the resin sealing member 5. is doing. Therefore, the insulative adhesive 41 prevents the resin sealing member 5 from entering between adjacent capacitor elements 2. Therefore, it is possible to reduce the cost by reducing the amount of the adhesive disposed between the adjacent capacitor elements 2 while preventing the occurrence of leakage current. Furthermore, the molding pressure of the resin sealing member 5 can be increased and the durability of the resin sealing member 5 can be improved. If the adhesive is disposed between the adjacent capacitor elements 2 in a solid shape, not only the cost increases, but also the capacitor element 2 may be cracked due to stress caused by thermal shrinkage in the drying process of the adhesive. .

  Further, when the insulating adhesive 41 is disposed between the adjacent capacitor elements 2, the interval between the adjacent capacitor elements 2 can be reduced, and the resin sealing member 5 enters between the adjacent capacitor elements 2. It becomes possible to prevent more reliably. Moreover, since the cathode layers 9 of the capacitor elements 2 are electrically connected to each other by the conductive adhesive 14 at the end portions, ESR (Equivalent Series Resistance) is reduced.

  Further, the insulating adhesive 41 is disposed between adjacent capacitor elements 2 so as to have a thickness that separates the resist layer 8 of one capacitor element 2 from the other capacitor element 2. As a result, even if the thickness of the resist layer 8 varies, the insulating adhesive 41 reliably adheres to each of the adjacent capacitor elements 2, so that sufficient bonding strength between the adjacent capacitor elements 2 can be obtained. .

Table 1 shows the yield per N / M when a conductive adhesive is used in place of the insulating adhesive 41 in the solid electrolytic capacitor 1 described above. As shown in FIG. 4, M (length of the outer periphery of the cathode layer 9) = (2 × m1) + (2 × m2), N (length of the inner periphery of the conductive adhesive instead of the insulating adhesive 41) S) = (2 × n1) + (2 × n2). As shown in Table 1, as N / M increases, the yield tends to increase. Even when the molding pressure of the resin sealing member 5 is small or large, the yield is obtained when N / M is 0.7 or more. It can be seen that exceeds 90%. As for the yield, a solid electrolytic capacitor having a small leakage current value (here, a solid electrolytic capacitor having a value of 0.06 CV or less) compared to a product αCV of an arbitrary coefficient α, capacitance C and rated voltage V Calculated by considering.

Table 2 shows the yield for each molding pressure (relative value) of the resin sealing member for the solid electrolytic capacitors of Comparative Example 1, Example 1 and Example 2. FIG. 5 is a graph showing the relationship between the molding pressure (relative value) of the resin sealing member and the yield for the solid electrolytic capacitors of Comparative Example 1, Example 1 and Example 2. Here, the solid electrolytic capacitor of Comparative Example 1 is one in which a conductive adhesive is arranged in an X shape so as to connect opposite corner portions in the cathode layer 9. In the solid electrolytic capacitor of Example 1, a conductive adhesive is arranged in a single rectangular ring along the outer edge portion of the cathode layer 9 (see FIG. 4). The solid electrolytic capacitor of Example 2 is a cathode. A conductive adhesive is arranged in a double rectangular ring along the outer edge portion of the layer 9 (see FIG. 6A). As shown in Table 2 and FIG. 5, if the molding pressure (relative value) is the same, the yield of the solid electrolytic capacitor of Example 1 is higher than the yield of the solid electrolytic capacitor of Comparative Example 1, and Example 1 It can be seen that the yield of the solid electrolytic capacitor of Example 2 tends to be higher than the yield of the solid electrolytic capacitor, and this tendency becomes more significant as the molding pressure (relative value) increases. The molding pressure (relative value): 0 is the case without the resin sealing member. The yield is a non-defective product of a solid electrolytic capacitor (here, a solid electrolytic capacitor of 0.06 CV or less) having a small leakage current value compared to the product αCV of an arbitrary coefficient α, capacitance C and rated voltage V. Calculated by considering.

  The present invention is not limited to the embodiment described above.

  For example, the adhesive disposed between adjacent capacitor elements is not limited to an insulating adhesive, and may be a conductive adhesive. In this case, the conductive adhesive 14 in the above embodiment is not necessary.

  Moreover, the adhesive agent arrange | positioned between adjacent capacitor | condenser elements may be further arrange | positioned in the inner part of a capacitor | condenser element. According to this, the joint strength between adjacent capacitor elements can be improved. FIG. 6A shows that the insulating adhesive 41 is formed in a rectangular ring shape on the inner side portion of the insulating adhesive 41 arranged in a rectangular ring shape so as to extend along the outer edge portion of the cathode layer 9 of the capacitor element 2. This is the case where they are further arranged. FIG. 6B shows that the insulating adhesive 41 is formed in an X shape on the inner side portion of the insulating adhesive 41 arranged in a rectangular ring shape so as to extend along the outer edge portion of the cathode layer 9 of the capacitor element 2. FIG. 6C shows a case where the insulating adhesive 41 is arranged in a rectangular ring shape so as to extend along the outer edge portion of the cathode layer 9 of the capacitor element 2. This is a case where a plurality of adhesives 41 are further arranged in a dot shape.

  Moreover, the adhesive agent arrange | positioned between adjacent capacitor | condenser elements should just be arrange | positioned so that it may extend along the outer edge part of the capacitor | condenser element which faces a resin sealing member at least. FIG. 6D shows a case where the conductive adhesive 41 is not disposed along the resist layer 8 of the capacitor element 2.

  Further, the capacitor element is not limited to the one disposed on the printed board, and the capacitor element may be disposed on the lead frame.

It is a longitudinal section of one embodiment of the solid electrolytic capacitor concerning the present invention. FIG. 2 is an exploded perspective view around a conductive member of the solid electrolytic capacitor of FIG. 1. It is a longitudinal cross-sectional view of the capacitor | condenser element of the solid electrolytic capacitor of FIG. It is a top view of the capacitor | condenser element of the solid electrolytic capacitor of FIG. It is a graph which shows the relationship between the molding pressure (relative value) of a resin sealing member, and a yield about the solid electrolytic capacitor of the comparative example 1, Example 1, and Example 2. FIG. It is a top view of the capacitor | condenser element of other embodiment of the solid electrolytic capacitor which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Solid electrolytic capacitor, 2 ... Capacitor element, 5 ... Resin sealing member, 6 ... Anode layer (1st conductor layer), 7 ... Dielectric layer, 8 ... Resist layer, 9 ... Cathode layer (2nd conductor) Layer), 14 ... conductive adhesive, 15 ... substrate, 41 ... insulating adhesive (adhesive).

Claims (5)

A capacitor element having a first conductor layer, a dielectric layer formed on both sides of the first conductor layer, and a second conductor layer formed outside the dielectric layer, and a plurality of stacked capacitor elements;
An adhesive disposed between the adjacent capacitor elements;
A resin sealing member covering the capacitor element,
The solid electrolytic capacitor, wherein the adhesive is disposed so as to extend along at least an outer edge portion of the capacitor element facing the resin sealing member.   The solid electrolytic capacitor according to claim 1, wherein the adhesive is arranged in a ring shape.   The solid electrolytic capacitor according to claim 1, wherein the adhesive is further disposed in an inner portion of the capacitor element. The adhesive is an insulating adhesive,
4. The solid electrolytic capacitor according to claim 1, wherein the second conductor layers are electrically connected to each other by a conductive adhesive at an end portion thereof. 5. The capacitor element has a resist layer that separates an outer edge portion of the second conductor layer from the first conductor layer,
5. The adhesive is disposed between adjacent capacitor elements so as to have a thickness that separates the resist layer of one of the capacitor elements from the other capacitor element. The solid electrolytic capacitor according to any one of the above.

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