JPH09148203A - Solid-state electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a projection out of a casing of a capacitor element, etc., even if pressure in the casing is increased owing to abnormal thermal stress at the time of soldering by a method wherein a projection is provided in a portion which comes into contact with sealing resin inside the cylindrical casing having a bottom and receiving the capacitor element. SOLUTION: In a capacitor element 6 in which an anode foil to which a lead terminal 1 is fitted and a cathode foil to which a lead terminal 2 is fitted are wound via a separator paper, TCNQ (7,7,8,8-tetracyanoquinodimethane) complex salt 7 used as an electrolyte is impregnated, and the capacitor element 6 is received in a cylindrical metal casing 58 having a bottom. Further, pulverulent body resin 4 is filled on the capacitor element 6, and an opening part of the metal casing 58 is sealed with hermetic resin 3, and inside the metal casing 58 coming into contact with the hermetic resin 3, a projection part 8 is provided. Thereby, even if thermal stress is applied at the time of soldering to increase pressure in the metal casing 58, it is possible to prevent a sealing member of the casing 58 or the capacitor element 6 therein from projecting out of the casing 58.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to a solid electrolytic capacitor using a solid electrolyte.

[0002]

2. Description of the Related Art A technique relating to a solid electrolytic capacitor using a complex salt of 7,7,8,8-tetracyanoquinodimethane (hereinafter abbreviated as TCNQ complex salt) as an electrolyte is disclosed in JP-B-62-
51491, JP-A-1-89729, JP-A 1-6
3527, JP-A-2-275612, JP-A-2-6
No. 3526 and Japanese Patent Laid-Open No. 2-96721.

A solid electrolytic capacitor using a TCNQ complex salt with isoquinoline or lutidine in which the N-position is substituted with an alkyl group has excellent high-frequency characteristics in addition to life and temperature characteristics, and is therefore widely used in switching power supplies and the like. Has been adopted.

[0004]

In recent years, due to the need for miniaturization of electronic equipment, it has been required for this type of solid electrolytic capacitor to be used as a surface mount component (chip component). There is a case where an abnormally strong heat stress is applied when attaching, and such heat stress (for example, 2
If it is applied at 40 ° C or higher for 1 minute or more), the pressure in the case in which the capacitor element is housed increases, and the sealing member of the case or the capacitor element in the case may protrude out of the case. There is.

According to the present invention, even if an abnormal thermal stress is applied during soldering to increase the pressure in the capacitor case, the sealing member of the case and the capacitor element in the case do not protrude out of the case. It is intended to clarify the structure of a solid electrolytic capacitor.

[0006]

In a solid electrolytic capacitor according to the present invention, a capacitor element obtained by winding an anode foil and a cathode foil with separator paper is impregnated with a TCNQ complex salt as an electrolyte. In a solid electrolytic capacitor which is housed in a bottomed cylindrical case and whose opening is sealed with an airtight resin, a convex portion is provided inside the case where the sealing resin is in contact. The above-mentioned case
The open end of the sleeve is curled inward or bent inward.

According to the above configuration of the present invention, the resin for sealing the case is locked by the convex portion inside the case, the curl portion at the end portion of the case, or the bent portion at the end portion of the case. Even if the pressure inside the capacitor case increases due to abnormal heat stress during soldering, the sealing resin and the capacitor element do not stick out of the case.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 1, a solid electrolytic capacitor according to a first embodiment of the present invention includes an anode foil having a lead terminal 1 attached and a cathode foil having a lead terminal 2 attached as a separator. Capacitor element 6 wound through paper
Is impregnated with TCNQ complex salt 7 as an electrolyte, the capacitor element is housed in a cylindrical metal case 58 having a bottom, the powder resin 4 is loaded on the capacitor element, and the opening of the case is hermetically sealed. In the solid electrolytic capacitor sealed with the conductive resin 3, a convex portion 8 is provided inside the case where the airtight resin 3 is in contact.

Further, in the solid electrolytic capacitor according to the second embodiment of the present invention, as shown in FIG. 2, a separator paper is used for the anode foil to which the lead terminal 1 is attached and the cathode foil to which the lead terminal 2 is attached. The TCNQ complex salt 7 as an electrolyte is impregnated in the capacitor element 6 wound via the above, the capacitor element is housed in a cylindrical metal case 59 having a bottom, and the powder resin 4 is loaded on the capacitor element. In the solid electrolytic capacitor in which the opening of the case is sealed with the airtight resin 3, the opening end 9 of the case is curled inward or bent inward. It is what

The solid electrolytic capacitors according to the first and second embodiments described above are manufactured through the following steps.

That is, first, a case 58 having the convex portion 8 as shown in FIG. 1 or a case 59 having the curl portion 9 as shown in FIG. The complex salt is melted by heating and liquefied, and the capacitor element 6 that has been preheated is immersed in the molten TCNQ complex salt, so that the capacitor element is impregnated with the TCNQ complex salt and immediately cooled to solidify the TCNQ complex salt.

Then, the powder resin 4 is loaded on the capacitor element, the airtight resin 3 such as softened or liquefied epoxy resin is injected from the opening of the case, and then the airtight resin is solidified to complete the process.

The amount of protrusion of the convex portion 8 and the curl portion 9 of the case from the inner circumferential surface of the case is such that the insertion of the capacitor element into the case is not hindered and the solid sealing resin can be locked. Specifically, the protrusion amount is about 0.2 mm to about 0.4 mm for a case having a diameter of 4 mm.

Convex portion 8 of the case in the first embodiment
May be, for example, about four dot-shaped projections or continuous linear projections.

The convex portion 8 and the curl portion 9 of the case are also provided.
May be formed by processing the case after housing the capacitor element in the case and before sealing the resin.

Here, 100 solid electrolytic capacitors each manufactured in accordance with the first and second embodiments described above and FIG.
As shown in (4), 100 conventional solid electrolytic capacitors in which no protrusions or curls are formed on the case 5 are subjected to thermal stress (24) by a vapor phase soldering device (VPS device).
(0 ° C. × 1 minute), and the appearance was abnormal, that is, whether or not the sealing resin and the capacitor element were partially protruded from the case. Table 1 shows the results.

[0017]

[Table 1]

As can be seen from Table 1, abnormal appearance may occur in the conventional example, whereas no abnormal appearance occurs in the examples of the present invention.

[0019]

According to the present invention, in a solid electrolytic capacitor with a resin sealing, even if the pressure inside the capacitor case increases due to abnormal thermal stress during soldering, the sealing resin and the capacitor element are kept outside the case. It does not protrude,
A solid electrolytic capacitor suitable for surface mounting is provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a solid electrolytic capacitor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a solid electrolytic capacitor according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a conventional solid electrolytic capacitor.

[Explanation of symbols]

 1 Anode lead terminal 2 Cathode lead terminal 3 Sealing resin 4 Powder resin 5 Case 58 Case 59 Case 6 Capacitor element 7 TCNQ complex salt 8 Case convex part 9 Case curl part

Claims (2)

[Claims] 1. A capacitor element in which an anode foil and a cathode foil are wound with separator paper in between is impregnated with a TCNQ complex salt as an electrolyte, and the capacitor element is housed in a bottomed cylindrical case, -A solid electrolytic capacitor in which an opening of a case is sealed with an airtight resin, wherein a convex portion is provided at a portion inside the case where the sealing resin is in contact with. 2. A capacitor element in which an anode foil and a cathode foil are wound with a separator paper in between is impregnated with a TCNQ complex salt as an electrolyte, and the capacitor element is housed in a bottomed cylindrical case, -A solid electrolytic capacitor in which the opening of the case is sealed with an airtight resin, wherein the opening end of the case is curled toward the inside or is bent toward the inside. Electrolytic capacitor.