JPH039322Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a chip-type electrolytic capacitor, and in particular, to heat radiation of its exterior member.

Chip-type electrolytic capacitors generally use a case made of thermoplastic synthetic resin, thermosetting synthetic resin, or a laminate of both as an exterior member.

As is well known, the case of an electrolytic capacitor is required to be sufficiently airtight, as the electrical characteristics will deteriorate if the electrolyte impregnated in the electrolytic capacitor element evaporates or if impurities such as moisture enter from the outside. .

In order to meet these requirements with synthetic resin, it is necessary to make the outer wall of the resin sufficiently thick. The proportion of the resin case is quite large.

Generally, synthetic resins have higher heat retention properties than metals, and cannot be expected to have a heat dissipation effect suitable for electrolytic capacitors.

Electrolytic capacitors generate heat due to chemical effects when energized, so it is necessary to dissipate heat.
If the temperature rises abnormally, the electrical characteristics become unstable, the synthetic resin case itself deteriorates, its airtightness is destroyed, and the electrolyte evaporates, resulting in a shortened lifespan.

Therefore, the object of this invention is to provide a chip-type electrolytic capacitor whose electrical characteristics are stabilized and reliability is increased by improving the heat dissipation effect of the outer case.

In other words, the chip-type electrolytic capacitor of this invention is
An electrolytic capacitor element 10 with flat tabs 12 and 14 pulled out from each end face, and a resin case piece (first case) molded from synthetic resin and having a recess 4 into which the electrolytic capacitor element is inserted. piece 2A), and plate-shaped terminal body parts 61, 81 that extend through the resin case piece and straddle the recessed part.
, tab connection parts 62 and 82 having a flat plate shape obtained by bending one end of the terminal body, and the other end of the terminal body exposed from the bottom of the resin case piece to the bottom of the resin case piece. external connection portions 63 and 83 formed by bending along , are integrally formed with a conductive metal plate, and the tab of the electrolytic capacitor element installed in the recess of the resin case piece is connected to the tab connection portion, Terminal portions 6 and 8 that support the electrolytic capacitor element with a gap 20 between them and the concave portion of the resin case piece; It is characterized by comprising a metal case piece (second case piece 2B) that accommodates the electrolytic capacitor element and the tab connection part of the terminal part in a sealed space formed on the case piece.

With this configuration, the heat generated by the electrolytic capacitor element is not directly transmitted to the resin case piece due to the gap between the recess formed in the resin case piece and the electrolytic capacitor element, and the entire surrounding area of the electrolytic capacitor element is free from space. Because of this, the heat generated by the electrolytic capacitor element can be efficiently dissipated from the metal case, which has a high heat dissipation effect.
It is possible to solve the problem that the heat generated by the electrolytic capacitor element is directly transmitted to the resin case piece that is in direct contact with the electrolytic capacitor element, causing the resin case piece itself to deteriorate and resulting in a decrease in reliability.

Hereinafter, this invention will be described in detail with reference to embodiments shown in the drawings.

1 to 3 show an embodiment of the chip-type electrolytic capacitor of this invention, FIG. 1 is a perspective view thereof, FIG. 2 is a sectional view taken along the - line, and FIG. 3 is a first case piece. FIG.

In each figure, a first case piece 2A serving as a resin case piece is molded using a thermoplastic synthetic resin, a thermosetting synthetic resin, or a lamination of both. This first case piece 2A has a recess 4 formed in its central portion, and terminal parts 6 and 8 are formed with this recess 4 in between. The terminal portions 6 and 8 are arranged symmetrically on the left and right, and
Terminal main body parts 61, 81 that penetrate the inside of the case piece 2A and form a plate shape, and the terminal main body parts 61, 81
Tab connection part 6 in the form of a flat plate with one end bent
2, 82 and the other end of the terminal main body portion 61, 81 pulled out from the bottom of the case piece 2A.
External connection part 6 formed by bending along the bottom part of
3,83.

An electrolytic capacitor element 10 is inserted into the recess 4, and tabs 12 and 14 are pulled out from both ends of the electrolytic capacitor element 10.
are welded to the tab connection parts 62 and 82 and support the electrolytic capacitor element 10 with a gap 20 between them and the recess 4. Electrolytic capacitor element 1
0, an anode foil and a cathode foil are wound together with a separator interposed therebetween, and tabs 12 and 14 are individually connected to the anode foil and the cathode foil and drawn out from the ends thereof.

A second case piece 2B as a metal case piece is installed opposite to the first case piece 2A, and the two are joined by ultrasonic welding or the like to maintain airtightness between them.

This second case piece 2B is molded from metal such as aluminum, and has a recess 16 formed therein opposite to the recess 4, and both form a storage space for the electrolytic capacitor element 10. There is. An inclined portion 18 serving as a display portion for determining the polarity of the terminal portions 6 and 8 is formed at a corner portion of the upper surface of the case piece 2B.

With the above structure, compared to cases where the entire electrolytic capacitor element is covered with synthetic resin or where the electrolytic capacitor element is supported by resin case pieces, part of the exterior member is made of metal and the elements are pulled out from both ends of the electrolytic capacitor element. Since the electrolytic capacitor element is supported with a gap formed in the recess formed in the resin case piece by the tab, the resin case piece itself will not deteriorate and a sufficient heat dissipation effect can be expected. As a result, the temperature rise of the electrolytic capacitor element can be suppressed, and changes in electrical characteristics caused by evaporation of the electrolytic solution or the like can be suppressed.

In particular, as in the example, since the synthetic resin case piece 2A is installed on the mounting member side, the insulation of the terminal part is high, and the metal case piece 2B is installed on the non-mounting member side. Therefore, the heat dissipation effect is improved and the electrolytic capacitor element is cooled well.

Furthermore, by making the end of the second case piece 2B bite into the inside of the first case piece 2A, the joint between both case pieces 2A and 2B becomes stronger.
Airtightness can be improved.

As explained above, according to this invention, a metal case piece is fixed to a resin case piece and the upper surface of the resin case piece is covered, and the electrolytic capacitor element and the tab connection part of the terminal part are placed in the sealed space formed on the resin case piece. In addition to supporting the electrolytic capacitor element with a gap between the tab and the recess, the heat dissipation effect is greater than that of a case made only of synthetic resin or a case where the electrolytic capacitor element is supported by an exterior case. The electrical characteristics of the electrolytic capacitor can be improved, stable characteristics can be maintained over a long period of time, and the structure is simple.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an embodiment of the chip-type electrolytic capacitor of this invention, Fig. 2 is a cross-sectional view taken along the - line in Fig. 1, and Fig. 3 is a plan view showing the mounting state inside the first case piece. It is a diagram. 2A...First case piece (resin case piece), 2
B... Second case piece (metal case piece), 4...
Recessed portion, 6, 8... Terminal portion, 61, 81... Terminal body portion, 62, 82... Tab connection portion, 63, 83...
...External connection part, 10... Electrolytic capacitor element, 1
2, 14...Tab, 20...Gap.

Claims (1)

[Claims for Utility Model Registration] An electrolytic capacitor element with a flat tab drawn out from each end face, a resin case piece molded from synthetic resin and having a recess into which the electrolytic capacitor element is inserted; A terminal main body portion having a plate shape and penetrating the resin case piece across the recess, a tab connecting portion having a flat plate shape obtained by bending one end of the terminal main body portion, and a tab connecting portion exposed from the bottom surface of the resin case piece. and an external connection portion formed by bending the other end of the terminal main body portion along the bottom surface of the resin case piece, and integrally formed with a conductive metal plate, and the electrolytic electrode installed in the recess of the resin case piece. a terminal portion to which the tab of the capacitor element is connected to the tab connection portion and to support the electrolytic capacitor element with a gap between the tab and the concave portion of the resin case piece; a metal case piece that covers the upper surface of the resin case piece and accommodates the electrolytic capacitor element and the tab connection part of the terminal part in a sealed space formed on the resin case piece;
A chip-type electrolytic capacitor characterized by comprising: