JP2003234251A - Chip type electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chip type electrolytic capacitor with junction strength retained unchanged between the capacitor element and the positive and negative terminal boards under the expansion of sealing resin during a thermal process for mounting. <P>SOLUTION: In the chip type electrolytic capacitor; a capacitor element has a column type positive electrode lead wire serving as a positive electrode and a negative electrode layer covering the positive electrode lead wire and serving as the negative electrode; a positive electrode terminal board is connected to the protruded positive electrode and a negative electrode terminal board is connected with the capacitor element with facing down thereto, and the terminal boards are sealed with a sealing resin; and the surfaces of the terminal boards are exposed flush with each other on the same surface of the sealing resin. It is characterized in that at least one of the two terminal boards has an engagement section to engage the sealing resin. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip-type electrolytic capacitor having a face-down structure.

[0002]

2. Description of the Related Art Recently, a structure of a chip type electrolytic capacitor in which electrodes (anode, cathode) are exposed and formed only on a lower surface (a surface facing a mounting substrate) of a chip type electrolytic capacitor has been widely adopted. As a concrete structure, unlike the structure that has been adopted so far where the electrode is pulled out from the side surface and bent to the lower surface, the capacitor element mounted inside is installed so as to bridge the anode terminal plate and the cathode terminal plate. (Face down structure). By adopting such a structure, the chip-type electrolytic capacitor can be downsized, and the possibility of short-circuiting with other electronic components mounted in the surroundings is reduced, resulting in higher packaging density. .

Such a conventional chip type electrolytic capacitor will be described below with reference to the drawings. FIG. 5 is a perspective view showing a conventional configuration of a chip type electrolytic capacitor. As shown in FIG. 5, the conventional chip-type electrolytic capacitor 1 is
The capacitor element 14 and the two terminal plates installed so as to bridge the capacitor element 14 are sealed with the sealing resin 15. The capacitor element 14 includes a substantially cylindrical anode lead wire 13 serving as an anode, and a cathode (layer) formed on the outer surface of the anode lead wire 13 via a dielectric layer (not shown). It That is, the anode lead wire 13 projects outward from one end of the capacitor element 14 having a substantially rectangular parallelepiped shape.
Further, the second terminal plate refers to a pair of conductive terminal plates including an anode terminal plate 11 and a cathode terminal plate 12. A connection tool 16 is installed on the upper surface of the anode terminal plate 11, and the anode lead wire 13 is connected to the connection tool 16 by welding, so that the anode terminal plate 11 and the anode lead wire 13 are indirectly connected to each other. Electrically connected. Further, the cathode (layer) which is the outer peripheral surface of the capacitor element 14 is electrically connected to the upper surface of the cathode terminal plate 12 via the conductive adhesive 17.

In this way, the conventional chip-type electrolytic capacitor in which the capacitor element 14 and the anode terminal plate 11 and the cathode terminal plate 12 electrically connected to the capacitor element 14 are sealed with the sealing resin 15 are known. Figure 6 shows the cross-sectional structure.
Shown in. As shown in FIG. 6, the sealing resin 15 seals the capacitor element 14, the connector 16, the anode terminal plate 11 and the cathode terminal plate 12 so as to cover the anode terminal plate 11 and the cathode terminal plate 12. The lower surface of each is exposed from the sealing resin 15 to form an electrode as a product of the chip-type electrolytic capacitor 1.

Here, in the detailed description of the present invention, the upper surface of the anode terminal plate 11 refers to the surface on which the connector 16 is installed or formed, and similarly, the upper surface of the cathode terminal plate 12 is the above-mentioned. It is assumed that the capacitor element 14 is a surface on which the conductive adhesive 17 is placed. The lower surface of the anode terminal plate 11 and the lower surface of the cathode terminal plate 12 are
In each of the terminal plates, it means the opposite surface facing the upper surface, particularly the exposed electrode surface of the chip-type electrolytic capacitor 1 without being covered with the sealing resin.

[Problems to be Solved by the Invention]

However, the conventional chip type electrolytic capacitor has the following problems. Cathode terminal plate 1
Most of 2 is connected to the capacitor element 14 by the conductive adhesive 17 having a weak connection strength, and the connection portion with the sealing resin 15 having a stronger connection strength than the conductive adhesive 17 is the edge of the cathode terminal plate 12. Is only part of Especially during heating, the stress caused by the outward expansion of the sealing resin 15 is
Cathode terminal plate 1 while holding the periphery of the capacitor element 14
2 on the upper surface of the capacitor element 14 and the cathode terminal plate 1
2 is relatively separated from each other, and the connection strength is further weakened. As described above, in a chip-type electrolytic capacitor that needs to be mounted on a mounting board or the like, the connection strength between the anode terminal plate 11 and the cathode terminal plate 12 and the sealing resin 15 becomes low in the heat treatment step at the time of mounting, and Element 14
A poor electrical connection between the anode terminal plate 11 and the cathode terminal plate 12 was likely to occur. Further, the connection between the anode lead wire 13 forming the anode and the anode terminal plate 11 is also made only by welding with the connecting tool 16. Therefore, for the stress generated when the sealing resin 15 expands,
Anode lead wire 13 and anode terminal plate 11 via connection tool 16
It was hard to say that the connection with was as strong as the cathode terminal plate described above.

The present invention has been made in view of the above problems in the prior art. Even when the sealing resin expands due to the heat treatment step at the time of mounting, the anode terminal plate, the cathode terminal plate, the capacitor element and It is an object of the present invention to provide a chip type electrolytic capacitor capable of maintaining the connection strength of the above.

[Means for Solving the Problems]

In the chip type electrolytic capacitor according to the first invention of the present application provided to solve the above-mentioned problems, a pillar-shaped anode lead wire forming an anode and a cathode layer covering the periphery of the anode lead wire form a cathode. And a terminal plate formed of a cathode terminal plate connected to the cathode by facing down the capacitor element and an anode terminal plate connected to the protruding anode, and In a chip-type electrolytic capacitor in which each surface of the terminal plate is exposed on the same surface of the sealing resin, a member for locking the sealing resin on at least one of the anode terminal plate and the cathode terminal plate. It is characterized in that a stop is formed.

With such a structure, the locking portion formed on at least one of the anode terminal plate and the cathode terminal plate is installed in a state of being fitted into the sealing resin. Therefore, not only the anode terminal plate and the cathode terminal plate are firmly fixed to the sealing resin, but also the stress caused by the expansion of the sealing resin during the heat treatment process is reduced and the separation of both terminal plates is prevented. You can

The chip type electrolytic capacitor according to the second invention of the present application provided to solve the above-mentioned problems is the chip type electrolytic capacitor according to claim 1, wherein the locking portion is formed on an end surface of the terminal plate. It is characterized in that it is a protrusion.

With this structure, the protrusion can efficiently receive the stress when the sealing resin expands, and prevent the anode terminal plate and the cathode terminal plate from peeling off.

A chip-type electrolytic capacitor according to a third invention of the present application, which is provided to solve the above-mentioned problems, is the chip-type electrolytic capacitor according to claim 1 or 2.
The locking portion is a groove portion formed on an end surface of the terminal plate.

With such a construction, not only the joint area with the sealing resin is increased by a simple process such as the formation of the groove portion to increase the joint force, but also the protruding portion formed relatively to the groove portion is expanded and sealed. It is possible to receive the stress of the stop resin and prevent separation of both terminal plates.

A chip-type electrolytic capacitor according to a fourth invention of the present application provided to solve the above-mentioned problems is the chip-type electrolytic capacitor according to any one of claims 1 to 3, wherein the locking portion is The pair of end faces is formed such that the surface area of the exposed surface of the terminal plate is gradually reduced from the surface area of the surface facing the surface.

In such a structure, the stress of the expanded sealing resin acts on the locking portion having such a shape so that the fitting force is increased instead of peeling off the joint portion. Therefore, it is possible to solve the problem of peeling of each member due to the expansion of the sealing resin, and to greatly increase the fitting force between the members.

A chip-type electrolytic capacitor according to a fifth invention of the present application provided to solve the above-mentioned problems is the chip-type electrolytic capacitor according to any one of claims 1 to 3, wherein the locking portion is , A pair of end faces formed in a tapered shape so as to be locked by the sealing resin in the direction of the exposed surface of the terminal plate.

With this structure, the stress of the expanded sealing resin can act not only in the direction of separating the cathode terminal plate from the capacitor element but also in the direction of canceling it. Therefore, the risk of product destruction due to peeling caused by thermal expansion can be reduced, and the selection range of the sealing resin and other members can be increased.

A chip-type electrolytic capacitor according to a sixth aspect of the present invention provided to solve the above-mentioned problems is the chip-type electrolytic capacitor according to any one of claims 1 to 5, wherein the locking portion is It is characterized in that the expanded sealing resin is urged in a direction opposite to the exposed surface of the terminal plate.

With such a structure, the stress of the expanded sealing resin can be received, and further acted in a direction in which it can be offset, so that the separation of both terminal plates can be prevented.

The chip type electrolytic capacitor according to the seventh invention of the present application, which is provided for solving the above-mentioned problems, is the same as the chip type electrolytic capacitor according to claim 6, wherein the engaging portion is provided with an anode lead wire. It is characterized in that it is a cutout portion which is formed to be open in the direction and has an end face which is formed in the direction of the surface where the terminal plate is exposed.

With such a structure, it is possible to disperse the stress direction in which the expanded sealing resin acts, and as a result, it is possible to prevent peeling of both electrode plates.

A chip-type electrolytic capacitor according to an eighth aspect of the present invention provided to solve the above-mentioned problems is the chip-type electrolytic capacitor according to any one of claims 1 to 7, wherein the cathode terminal plate is It is characterized in that a concave portion is formed on the surface facing the cathode.

With such a structure, it is possible to secure a sufficient area for the conductive adhesive connecting the cathode (layer) of the capacitor element and the cathode terminal plate to be bonded to the cathode terminal plate. As a result, it helps reduce peeling of the cathode terminal plate.

A chip-type electrolytic capacitor according to a ninth invention of the present application, which is provided to solve the above-mentioned problems, is the chip-type electrolytic capacitor according to claim 8, wherein the recess is
It is characterized in that it has a portion in which the hole diameter inside is larger than the hole diameter of the opening.

With such a structure, the conductive adhesive is firmly fitted to the cathode plate terminal and the anchor effect is produced, so that the peeling of the cathode terminal plate can be further reduced.

DETAILED DESCRIPTION OF THE INVENTION

The structure of one embodiment of the chip-type electrolytic capacitor according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the configuration of an embodiment of a chip-type electrolytic capacitor according to the present invention.
As shown in FIG. 1, a chip-type electrolytic capacitor 1 according to the present invention includes a capacitor element 14 and its capacitor element 1.
The anode terminal plate 11 and the cathode terminal plate 12 installed so as to bridge 4 are sealed with a sealing resin 15. The capacitor element 14 includes a substantially cylindrical anode lead wire 13 serving as an anode, and a cathode (layer) formed on the outer surface of the anode lead wire 13 via a dielectric layer (not shown). It That is, the anode lead wire 13 projects outward from one end of the capacitor element 14 having a substantially rectangular parallelepiped shape. Anode terminal plate 11
The connection tool 16 is installed on the upper surface of the
Since the anode lead wire 13 is connected to 6 by welding, the anode terminal plate 11 and the anode lead wire 13 are indirectly electrically connected. Further, the cathode (layer) which is the outer peripheral surface of the capacitor element 14 is electrically connected to the upper surface of the cathode terminal plate 12 via the conductive adhesive 17.

Further, the sealing resin 1 is also used in the present invention as in the conventional case.
5 is a capacitor element 14, a connector 16, an anode terminal plate 11
The cathode terminal plate 12 and the cathode terminal plate 12 are sealed so as to cover them, but the lower surfaces of the anode terminal plate 11 and the cathode terminal plate 12 are exposed from the sealing resin 15 in order to form electrodes as a product of the chip-type electrolytic capacitor 1. is doing.

Here, in the chip type electrolytic capacitor according to the present invention, the engaging portion 101 is formed on at least one of the anode terminal plate 11 and the cathode terminal plate 12. As shown in FIG. 1, the engaging portion 101 has a protrusion 101a, a groove portion 101c, and a similar end surface formed in a V shape on the end surface of at least one of the anode terminal plate 11 and the cathode terminal plate 12. A shape such as the cutout portion 101b can be given. It is desirable that the location where the notch 101b is formed is set so that the anode terminal plate 11 and the cathode terminal plate 12 are opened in opposite directions, not in a positional relationship in which they face each other.

FIG. 2 is a top (transmission) view showing the structure of one embodiment of the chip-type electrolytic capacitor according to the present invention. As shown in FIG. 2, the anode terminal plate 11 and the cathode terminal plate 12 have notches 101b so that they are opened oppositely in the direction in which the anode lead wire 13 is installed.
Are formed. Further, a groove portion 101c is formed on the end surface of the anode terminal plate 11 corresponding to the side surface of the chip type electrolytic capacitor 1.
The groove portion 101c has a groove formed in parallel with the installation direction of the anode lead wire 13. Further, similarly to the groove portion 101c, the protruding portion 1 is provided on the end surface of the cathode terminal plate 12 corresponding to the side surface of the chip type electrolytic capacitor 1.
01a is formed, and the protruding portion 101a is formed with a continuous protruding portion parallel to the installation direction of the anode lead wire 13.

Next, the structure of the cutout portion 101b will be described below with reference to FIG. 3 which is a sectional view taken along line AA of FIG. As shown in FIG. 3A, the cutout portion 101b
Not only notches the cathode terminal plate 12, but also inclines it so that its end face extends in the direction of the lower surface. The shape of the end surface means that the cathode terminal plate 12 is inclined (in the direction of the arrow) so as to be biased when the sealing resin 15 is expanded by the heat treatment. Further, as another embodiment of the chip-type electrolytic capacitor according to the present invention, the shape of the notch 101b may be a curved shape as shown in FIG. 3 (b). Further, as shown in FIG. 3B, the protrusion 10 formed on the side end surface of the cathode terminal plate 12.
The lower part may be tapered so that the cathode terminal plate 12 is biased when the sealing resin 15 expands. In addition, as shown in FIG. 4, a plurality of recesses may be formed on the upper surface of the cathode terminal plate 12 in order to increase the connection strength between the cathode terminal plate 12 and the capacitor element 14. At this time, the shape of the concave portion is set so that the hole diameter inside thereof is larger than the hole diameter of the opening. Thus, the capacitor element 14 and the capacitor element 14
Anode terminal plate 11 and cathode terminal plate 1 electrically connected to
2 is sealed by the sealing resin 15 to form the chip-type electrolytic capacitor according to the present invention.

【The invention's effect】

As described above, according to the chip-type electrolytic capacitor of the present invention, the sealing resin is filled so that the locking portion fits into the terminal. The connection strength between the plate and the sealing resin increases. Further, since the end face of the cutout portion has a tapered shape, the terminal plate is not easily peeled off from the sealing resin. That is, it is possible to increase the connection strength between the anode terminal plate and the cathode terminal plate and the sealing resin, and as a result, it is possible to reduce the electrical connection failure between the capacitor element and the anode terminal plate and the cathode terminal plate. .

[Brief description of drawings]

FIG. 1 is a perspective view showing the structure of an embodiment of a chip-type electrolytic capacitor according to the present invention.

FIG. 2 is a top (transmission) view showing the structure of one embodiment of the chip-type electrolytic capacitor according to the present invention.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a cross-sectional view (partial view) showing an upper surface of a cathode terminal plate in another embodiment of the chip-type electrolytic capacitor according to the present invention.

FIG. 5 is a perspective view showing a conventional structure of a chip type electrolytic capacitor.

6 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

1. Chip type electrolytic capacitor 11. Anode terminal plate 12. Cathode terminal plate 13. Element anode lead wire 14. Capacitor element 15. Sealing resin 16. Connection 17. Conductive adhesive 101a. protrusion 101b. Cutout 101c. Groove

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Setsu Mukai             5-7 Shiba 5-1, Minato-ku, Tokyo NEC Corporation             Inside the company (72) Inventor Kazushi Takada             560 Irizen, Izenzen-cho, Shimoshinagawa-gun, Toyama Toyama             Within NEC Corporation

Claims (9)

[Claims] 1. A column-shaped anode lead wire forming an anode and a capacitor element having a cathode layer covering the periphery of the anode lead wire as a cathode, an anode terminal plate connected to the protruding anode, and the capacitor. The element face down and a terminal plate composed of a cathode terminal plate connected to the cathode are sealed with a sealing resin, and each surface of the terminal plate is exposed on the same surface of the sealing resin. In the chip type electrolytic capacitor, the chip type electrolytic capacitor is characterized in that a locking portion for locking the sealing resin is formed on at least one of the anode terminal plate and the cathode terminal plate. 2. The chip-type electrolytic capacitor according to claim 1, wherein the engaging portion is a protrusion formed on an end surface of the terminal plate. 3. The locking portion is a groove portion formed on an end surface of the terminal plate, wherein the locking portion is a groove portion.
The chip type electrolytic capacitor described in. 4. The pair of end faces of the locking portion are formed so that the surface area of the exposed surface of the terminal plate is gradually reduced from the surface area of the surface facing the terminal plate. The chip-type electrolytic capacitor according to any one of claims 1 to 3. 5. A pair of end surfaces formed in a taper shape in a manner that the locking portions are locked to the sealing resin in the direction of the exposed surface of the terminal plate. The chip type electrolytic capacitor according to claim 3. 6. The locking portion is formed in such a manner that the expanded sealing resin is urged in a direction opposite to the exposed surface of the terminal plate. The chip type electrolytic capacitor described in Kaichi. 7. The notch portion is a notch portion having an end face formed to be open in a direction in which an anode lead wire is installed and having an open shape in a direction in which a terminal plate is exposed. The chip-type electrolytic capacitor according to claim 6, wherein the chip-type electrolytic capacitor is present. 8. The chip type electrolytic capacitor according to claim 1, wherein a concave portion is formed on a surface of the cathode terminal plate facing the cathode. 9. The chip-type electrolytic capacitor according to claim 8, wherein the recess has a portion in which the hole diameter inside is larger than the hole diameter of the opening.