JP2009206149A - Surface-mounted thin electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin surface-mounted electrolytic which can stably connect a capacitor element with a lower surface electrode provided on an exterior case and reduce failures in characteristics during a manufacturing process, and which has stable characteristics in evaluating long-term reliability. <P>SOLUTION: A support structure for defining a height position of the capacitor element 20 is formed inside the exterior case 2 so that a distance between an anode of the capacitor element 20 and an anode terminal 6 of the exterior case 2 and a distance between a cathode 8 of the element 20 and a cathode terminal 7 of the case 2 are always constant. For example, a lower surface of a connection spacer 4 of the anode is in contact with an upper surface of a resin block 9 formed on an inner bottom face of the exterior case 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a surface-mounting thin electrolytic capacitor, and more particularly to a surface-mounting thin electrolytic capacitor having an outer case and a lower surface electrode connection structure capable of maintaining stable capacitor characteristics.

  FIG. 6 shows a conventional surface mount thin electrolytic capacitor. FIG. 6A is a front sectional view of the entire surface mount thin electrolytic capacitor, and shows only a cut surface of the cross section. FIG. 6B is a plan view when the outer case cover is removed from the entire surface mount thin electrolytic capacitor. As shown in FIG. 6, a connection spacer 4 is welded to the anode portions at both ends of a flat plate capacitor element 20 having a cathode portion 8 in the vicinity of the center portion to produce a capacitor element laminate, and conductive on the inner bottom surface of the outer case 2. The connection spacer 4 and the cathode portion 8 are connected to the upper surfaces of the anode terminal 6 and the cathode terminal 7 by the adhesive 5, respectively. Such an electrolytic capacitor is often called a three-terminal transmission line element.

  The electrolytic capacitor according to this prior art has a conductive functional polymer film as a solid electrolyte, and an anodic oxide coating layer is formed on the surface of the valve action metal to form an anode body of the valve action metal. A conductive functional polymer film is formed so as to cover the center of the surface, a graphite layer is formed around the conductive polymer film, a silver paste layer is sequentially formed as a cathode layer, and then an anode terminal 6 and a cathode terminal 7 are formed. The exterior case 2 is connected with the conductive adhesive 5, and then the exterior case cover 1 is bonded and fixed using the adhesive 3. A similar technique is disclosed in Patent Document 1, for example.

  Specifically, a liquid conductive adhesive 5 is applied onto the anode terminal 6 and the cathode terminal 7 of the outer case 2, and a capacitor element or a laminate thereof is placed thereon, dried and solidified, and the anode portion and the cathode Each part is fixedly connected.

  The detailed structure of the exterior case is shown in FIG. FIG. 7A is a front sectional view of the exterior case cover 1 and shows only a cut surface of the cross section. FIG. 7B is a bottom view of the exterior case cover 1, FIG. 7C is a front sectional view showing only the cut surface of the exterior case 2, and FIG. 7D is a plan view of the exterior case 2. The exterior case 2 has a box shape with an open top surface, and an anode terminal 6 and a cathode terminal 7 are provided at the bottom. Moreover, the resin block part 9 is also provided, and as shown in FIG. 7C, the upper surface of the resin block part 9 is higher than the upper surfaces of the anode terminal 6 and the cathode terminal 7, and this upper surface is the cathode part 8 (FIG. 6) is substantially in contact with the anode side end of the lower surface.

  A specific process for housing the capacitor element in the outer case 2 and connecting the anode part and the cathode part to the anode terminal and the cathode terminal, respectively, is as follows. First, a liquid conductive adhesive is applied on the anode terminal and the cathode terminal in the outer case, and the capacitor element laminate is placed thereon, dried and solidified, and the anode part and the cathode part are fixedly connected to each other. However, if the conductive adhesive is insufficient due to variations in the mounting position of the capacitor element stack on the outer case, the connection area between the anode and cathode parts of the capacitor element and the anode and cathode terminals of the outer case is insufficient. However, when a defect in the connection resistance is large and excessive, the anode part and the cathode part are bridged (short-circuited) by the liquid conductive adhesive, resulting in a defect in a large leakage current.

JP 2006-128247 A

  As already explained in part, in the conventional exterior structure of a surface mount thin electrolytic capacitor, the bonding state of the anode part and the cathode part of the capacitor element and the anode terminal and the cathode terminal of the outer case depends on the amount of the conductive adhesive applied. Even if the amount of the conductive adhesive is constant due to the distribution situation, a connection area shortage and a bridge between the anode part and the cathode part occur due to variations in the mounting position of the capacitor element in the outer case.

  Further details will be described based on the drawings. FIG. 8 is a front sectional view showing a capacitor element position shift in a conventional surface mount thin electrolytic capacitor. That is, in FIG. 8, due to the displacement of the capacitor element, the connection spacer 4 welded to the left anode end rides on the resin block portion 9 on the inner bottom surface of the outer case 2. Has occurred. In addition, the capacitor element 20 is tilted, the anode end on the right side is lowered, and the conductive adhesive 5 causes a short circuit portion 10 between the connection spacer 4 at the anode end and the cathode portion of the capacitor element 20. Thus, even if the application amount of the conductive adhesive 5 is not excessive, a short circuit between the anode part and the cathode part may occur.

  FIG. 9 is a front sectional view of the conventional surface mount thin electrolytic capacitor in the case of excessive conductive adhesive. That is, FIG. 9 shows a state where the anode portion and the cathode portion 8 of the capacitor element are short-circuited by the excessive conductive adhesive 5. Thus, even if there is no position shift of the capacitor element 20, the short circuit part 10 between the anode part and the cathode part may occur.

  Due to the shortage of the connection area and the bridge between the anode part and the cathode part, characteristic changes are likely to occur in environmental changes such as an increase in characteristic defects in the manufacturing process and long-term reliability evaluation.

  In this situation, the problem of the present invention is that when the capacitor element or the laminated body is connected to the anode terminal and the cathode terminal inside the outer case by using a conductive adhesive, it is easy to manufacture and for a long time. It is an object of the present invention to provide a surface mount thin electrolytic capacitor that is less likely to change its characteristics due to environmental changes.

  In the present invention, in order to solve the above problems, a constant space is always provided between the anode part of the capacitor element and the anode terminal part in the outer case, and between the cathode part of the capacitor element and the cathode terminal part of the outer case. As a result, a surface-mounted thin electrolytic capacitor can be obtained in which the connection by the conductive adhesive is stable, the characteristic failure in the manufacturing process can be reduced, and the characteristic is stable in an environmental change such as long-term reliability evaluation.

  Further, even if the liquid conductive adhesive protrudes from the anode side to the cathode side or from the cathode side to the anode side, a space portion is provided between the capacitor element and the resin block portion of the outer case, so that the anode portion And the cathode part can be prevented from being short-circuited, and the defect rate can be reduced.

  In addition, in order to provide the space portion, it is necessary to accurately determine the position of the capacitor element in the height direction. The structure supported by the convex part of the provided insulating material was given.

  That is, the surface mount thin electrolytic capacitor of the present invention is a plate-like capacitor element having an anode part at the end and a cathode part at the center, or a capacitor element laminate formed by laminating the plate element, and connected to the anode part. A surface mount thin electrolytic capacitor, wherein the anode terminal and the cathode terminal connected to the cathode portion are packaged with a case using an insulating material so that the anode terminal and the cathode terminal serve as lower surface electrodes, A connection spacer is added to the bottom surface side of the anode portion of the capacitor element, the connection spacer is connected to the anode terminal surface of the outer surface of the outer case through a conductive adhesive, and the cathode terminal surface of the inner surface of the outer case is connected to the cathode terminal surface. The cathode part is connected via a conductive adhesive, the lower surface of the connecting spacer of the anode part in the lowermost capacitor element is in contact with the convex part of the insulating material formed on the inner bottom surface of the outer case, and the lowermost part Between the anode-side below the end face of the cathode portion of the capacitor element and the upper surface of the convex portion and a space portion as the gap is formed.

  Further, the surface mount thin electrolytic capacitor of the present invention is a plate-like capacitor element having an anode part at the end and a cathode part at the center, or a capacitor element laminate formed by laminating this, and connected to the anode part. A surface mount thin electrolytic capacitor, wherein the anode terminal and the cathode terminal connected to the cathode portion are packaged with a case using an insulating material so that the anode terminal and the cathode terminal serve as lower surface electrodes, A connection spacer is added to the bottom surface side of the anode portion of the capacitor element, the connection spacer is connected to the anode terminal surface of the outer surface of the outer case through a conductive adhesive, and the cathode terminal surface of the inner surface of the outer case is connected to the cathode terminal surface. The cathode portion is connected via a conductive adhesive, and the lower surface of the cathode portion of the lowermost capacitor element is in contact with the uppermost surface of the convex portion of the insulating material formed on the inner bottom surface of the outer case, so that the lowermost capacitor element And a space portion as the gap is formed between the anode-side below the end face of the cathode portion between said convex portion.

  The convex portion is formed on the inner bottom surface of the outer case as an insulating material block portion, a step is formed on the upper surface of the insulating material block portion, the lower surface is on the anode side of the capacitor element, and the higher surface Is on the center side of the cathode portion of the capacitor element, the higher surface of which is in contact with the lower surface of the cathode portion of the capacitor element, and a gap is formed between the lower surface and the lower surface of the anode side end portion of the cathode portion. A space portion may be formed.

  Further, the surface mount thin electrolytic capacitor of the present invention is a plate-like capacitor element having an anode part at the end and a cathode part at the center, or a capacitor element laminate formed by laminating this, and connected to the anode part. A surface mount thin electrolytic capacitor, wherein the anode terminal and the cathode terminal connected to the cathode portion are packaged with a case using an insulating material so that the anode terminal and the cathode terminal serve as lower surface electrodes, A connection spacer is added to the bottom surface side of the anode portion of the capacitor element, the connection spacer is connected to the anode terminal surface of the outer surface of the outer case through a conductive adhesive, and the cathode terminal surface of the inner surface of the outer case is connected to the cathode terminal surface. The cathode part is connected via a conductive adhesive, and the cathode part of the lowermost capacitor element is disposed on the bottom surface inside the outer case of the conductive adhesive that connects the connecting spacer of the anode part to the upper surface of the anode terminal. A first insulating material block portion having an upper surface at a position lower than the surface is provided in the outer case inner bottom surface of the conductive adhesive side connecting the cathode portion to the upper surface of the cathode terminal and in contact with the lower surface of the cathode portion. A second insulating material block portion is provided.

  According to the present invention, a conductive adhesive is always provided between the anode part of the capacitor element and the anode terminal part in the outer case, and between the cathode part of the capacitor element and the cathode terminal part of the outer case. In the connection via the network, a more stable connection is possible, and the reliability can be further improved.

  Further, when using a case having an anode terminal and a cathode terminal on the bottom surface portion of the insulating material case, a space portion is formed between the anode side end portion of the cathode portion of the capacitor element and the insulating material block portion in the exterior case. By providing, it is possible to prevent a short circuit due to the conductive adhesive between the anode part and the cathode part, and to reduce the defect rate in the manufacturing process.

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

  (Embodiment 1) FIG. 1 is a schematic front sectional view showing the entire structure of a surface mount thin electrolytic capacitor according to Embodiment 1 of the present invention. FIG. 1 is a cross-sectional view showing only the cut end, and the conductive adhesive 5 is also shown in the shape of the cut end. However, in order to display the distribution range in an easy-to-understand manner, it is shown by a dot pattern instead of hatching. . As shown in the figure, the connection spacer 4 is elongated in the direction of the center of the product, so that it is always placed on the resin block portion 9 so that the vertical position of the capacitor element 20 is fixed, thereby preventing a short circuit. A space portion 12 is obtained.

  Thus, for example, as shown in a front sectional view in FIG. 5, the upper surface of the resin block portion 9 and the lower surface of the cathode portion 8 are in a state where the lower surface of the connection spacer 4 of the anode portion is in contact with the upper surface of the resin block portion 9. As shown as a non-short-circuit portion 14 with a space in between, the connection spacer 4 and the cathode portion 8 of the anode portion are generated via the conductive adhesive 5 even when the conductive adhesive 5 becomes excessive. Short circuit can be reduced. Furthermore, when the conductive adhesive 5 is in a liquid state before solidifying, the connection spacer of the capacitor element comes into contact with the resin surface inside the outer case without the conductive adhesive 5. The element is not lifted up, and it is easy to align not only the vertical position of the capacitor element but also the horizontal position.

  The outer case used in the present embodiment is manufactured by a known technique by insert molding using a lead frame metal material for the anode and cathode terminals of the bottom electrode and an epoxy resin as an insulating material. However, in addition to the resin, a resin containing an inorganic filler may be used as the insulating material, or ceramics may be used. The exterior case cover 1 is also made of the same insulating material and is fixed to the exterior case 2 with an adhesive 3.

(Embodiment 2) FIG. 2 is a schematic front sectional view showing the entire structure of a surface mount thin electrolytic capacitor according to Embodiment 2 of the present invention. By elongating the resin block portion 9 in the product outer side direction, the connection spacer 4 is always placed on the resin block portion 9 and the position is fixed, and the short-circuit prevention space portion 12 is obtained. That is, the short-circuit prevention space portion 12 is formed by contacting the resin block portion on the inner surface of the outer case and the connection spacer of the anode portion without using the conductive adhesive 5.

(Embodiment 3) FIG. 3 is a front sectional view showing an entire surface mount thin electrolytic capacitor according to Embodiment 3 of the present invention. By providing a step on the upper surface of the resin block portion 9, the capacitor element 20 is always fixed at a fixed position (height), and a short-circuit preventing space portion 12 is obtained. As a result, a short-circuit prevention space portion 12 is formed between the lower end surface of the resin block portion 9 at the end portion on the anode portion side of the cathode portion 8 where the short circuit via the conductive adhesive 5 is likely to occur. Even if the conductive adhesive 5 spreads on the lower surface, a short circuit does not occur immediately. In addition, this level | step difference is not restricted to 2 steps | paragraphs shape like FIG. 3, Furthermore, there may be a multistage or an inclined surface.

(Embodiment 4) FIG. 4 is a front sectional view showing the entire structure of a surface mount thin electrolytic capacitor according to Embodiment 4 of the present invention. In addition to the resin block portion 9 (first insulating material block portion), the additional resin block portion 13 (second insulating material block portion) is added so that the capacitor element 20 is always fixed at a fixed position (height). Thus, the space portion 12 for preventing a short circuit is obtained. Even in this embodiment, even if the conductive adhesive 5 spreads on the upper surface of the resin block portion 9, the occurrence of a short circuit (bridge) can be reduced.

  As shown in FIGS. 1, 2, 3, and 4, the connection spacer 4 and the capacitor element 20 are always at a constant distance from the anode terminal 6 and the cathode terminal 7. A stable connection is possible.

  According to the first to fourth embodiments of the present invention, the application amount of the conductive adhesive 5 does not need to be strictly controlled by the clearances of the connection spacer 4 and the capacitor element 20, and the anode terminal 6 and the cathode terminal, thereby providing a more stable connection. Thus, it is possible not only to reduce characteristic defects in the manufacturing process, but also to produce a surface mount thin electrolytic capacitor whose characteristics are stable in environmental changes such as long-term reliability evaluation.

  The exterior case used for the surface-mount thin electrolytic capacitor of the present invention can be applied to an electronic component that is surface-mounted on a printed circuit board and has an electrode formed on the bottom surface of the product.

1 is an overall front sectional view showing a surface-mounted thin electrolytic capacitor according to Embodiment 1 of the present invention. FIG. The whole front sectional view which shows the surface mount thin electrolytic capacitor by Embodiment 2 of this invention. The whole front sectional view which shows the surface mount thin electrolytic capacitor by Embodiment 3 of this invention. The whole front sectional view showing the surface mounting thin electrolytic capacitor by Embodiment 4 of the present invention. FIG. 3 is a front sectional view when the amount of the conductive adhesive in the first embodiment of the present invention is large. 6 shows a conventional surface mount thin electrolytic capacitor, FIG. 6A is a front sectional view of the entire surface mount thin electrolytic capacitor, and FIG. 6B is a plan view when the exterior case cover is removed from the entire surface mount thin electrolytic capacitor. . FIG. 7A is a front sectional view of an exterior case cover, FIG. 7B is a bottom view of the exterior case cover, and FIG. 7C is an exterior case. FIG. 7D is a plan view of the exterior case. FIG. 6 is a front sectional view showing a capacitor element position shift in a conventional surface mount thin electrolytic capacitor. FIG. 6 is a front sectional view showing a case where a conductive adhesive is excessive in a conventional surface mount thin electrolytic capacitor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exterior case cover 2 Exterior case 3 Adhesive 4 Connection spacer 5 Conductive adhesive 6 Anode terminal 7 Cathode terminal 8 Cathode part 9 Resin block part 10 Short-circuit part 11 Connection area reduction part 12 Short-circuit prevention space part 13 Additional resin block part 14 Non-short circuit part 20 Capacitor element

Claims (4)

A plate-shaped capacitor element having an anode part at the end and a cathode part at the center part or a capacitor element laminate formed by laminating this, an anode terminal connected to the anode part, and connected to the cathode part The cathode terminal is a surface-mounted thin electrolytic capacitor that is packaged with a case using an insulating material so that the anode terminal and the cathode terminal serve as a bottom electrode,
A connection spacer is added to the bottom side of the anode part of the capacitor element,
The connection spacer is connected to the anode terminal surface on the inner surface of the outer case through a conductive adhesive,
The cathode part is connected to the cathode terminal surface of the inner surface of the outer case through a conductive adhesive,
The lower surface of the connecting spacer of the anode portion in the lowermost capacitor element is in contact with the convex portion of the insulating material formed on the bottom surface inside the outer case,
A surface-mounting thin electrolytic capacitor characterized in that a space is formed between the lower surface of the anode side end of the cathode portion of the lowermost capacitor element and the upper surface of the convex portion. A plate-shaped capacitor element having an anode part at the end and a cathode part at the center part or a capacitor element laminate formed by laminating this, an anode terminal connected to the anode part, and connected to the cathode part The cathode terminal is a surface-mounted thin electrolytic capacitor that is packaged with a case using an insulating material so that the anode terminal and the cathode terminal serve as a bottom electrode,
A connection spacer is added to the bottom side of the anode part of the capacitor element,
The connection spacer is connected to the anode terminal surface on the inner surface of the outer case through a conductive adhesive,
The cathode part is connected to the cathode terminal surface of the inner surface of the outer case through a conductive adhesive,
The lower surface of the cathode portion of the lowermost capacitor element is in contact with the uppermost surface of the convex portion of the insulating material formed on the inner bottom surface of the outer case,
A surface-mounting thin electrolytic capacitor, wherein a space portion is formed between the lower surface of the anode side end portion of the cathode portion of the lowermost capacitor element and the convex portion. The convex portion is formed on the inner bottom surface of the outer case as an insulating material block portion, a step is formed on the upper surface of the insulating material block portion, the lower surface is on the anode side of the capacitor element, and the higher surface Is on the center side of the cathode portion of the capacitor element, the higher surface of which is in contact with the lower surface of the cathode portion of the capacitor element, and a gap is formed between the lower surface and the lower surface of the anode side end portion of the cathode portion. The surface-mounting thin electrolytic capacitor according to claim 2, wherein a space is formed.
A plate-shaped capacitor element having an anode part at the end and a cathode part at the center part or a capacitor element laminate formed by laminating this, an anode terminal connected to the anode part, and connected to the cathode part The cathode terminal is a surface-mounted thin electrolytic capacitor that is packaged with a case using an insulating material so that the anode terminal and the cathode terminal serve as a bottom electrode,
A connection spacer is added to the bottom side of the anode part of the capacitor element,
The connection spacer is connected to the anode terminal surface on the inner surface of the outer case through a conductive adhesive,
The cathode part is connected to the cathode terminal surface of the inner surface of the outer case through a conductive adhesive,
A first insulating material block having an upper surface at a position lower than the lower surface of the cathode portion of the lowermost capacitor element on the inner case bottom surface of the conductive adhesive side connecting the anode portion connection spacer to the upper surface of the anode terminal Part is provided,
A surface-mounting thin electrolytic capacitor characterized in that a second insulating material block portion in contact with the lower surface of the cathode portion is provided on the bottom surface inside the exterior case on the conductive adhesive side connecting the cathode portion to the upper surface of the cathode terminal .

Images