JPH05243097A - Solid-state electrolytic capacitor - Google Patents

Abstract

PURPOSE:To provide a manufacturing method for a solid-state electrolytic capacitor having a minimum change in leakage current and excellent heat resistance even against thermal stress. CONSTITUTION:This solid-state electrolytic capacitor comprises a capacitor element 6 composed of an anode foil 1 and a cathode foil 2 wound around a separator 3, TCNQ salt 8 which is saturated into the capacitor element 6 and then cooled and solidified, and fluorine contained resin which is penetrated into the capacitor device. The introduction of fluorine contained resin into the capacitor device and its surface minimizes the thermal stress of TCNQ salt and improves its leakage current characteristic.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a solid electrolyte, TC
The present invention relates to a solid electrolytic capacitor using NQ salt.

[0002]

The applicant of the present application has already proposed various organic semiconductor solid electrolytic capacitors using TCNQ salt as an electrolyte. That is, JP-A-58-19141
No. 4 (H01G 9/02) and the like, a solid electrolytic capacitor using a TCNQ salt with isoquinoline in which the N-position is substituted with an alkyl group has particularly excellent high-frequency characteristics, and therefore is used for switching power supplies, etc. However, in recent years, due to the need for downsizing of devices, this type of capacitor is also required to be used as a surface mounting component (chip component).

However, the above-mentioned conventional capacitor cannot withstand the thermal stress (usually 230 ° C.) at the time of soldering, which is indispensable for surface mounting parts,
There is a drawback in that the characteristics such as a remarkable increase in leakage current are brought about.

In order to remedy this drawback, the applicant of the present application proposes to carry out a voltage treatment (aging) at a temperature of 150 ° C. or higher. That is, JP-A-2-2788
No. 07 (H01G 9/04), a capacitor is housed in a cylindrical perforated hot plate heated to a predetermined temperature of 150 ° C. or higher, and is subjected to aging while applying a rated voltage. This prevents the characteristic deterioration due to the leakage current.

[0005]

According to the above-mentioned conventional technique, it is possible to prevent the characteristic deterioration due to the leakage current to some extent, but it is possible to completely prevent the leakage current from increasing when the soldering is performed by the reflow. I can't. Therefore, the present invention reliably prevents an increase in leakage current after reflow soldering.

[0006]

The present invention is to improve the above-mentioned drawbacks of the prior art, and includes a capacitor element in which an anode foil and a cathode foil are wound with a separator interposed therebetween,
It is characterized in that the capacitor element is composed of a TCNQ salt which is cooled and solidified after impregnation and a fluororesin permeated into the inside of the capacitor element. Further, the fluororesin is further coated with a thermosetting resin, preferably a powder resin.

[0007]

FUNCTION Fluorine resin is a chemically inert substance having a small friction coefficient, excellent heat resistance and chemical resistance, extremely low water absorption and moisture permeability. The present invention utilizes the characteristics of this fluororesin. That is, by introducing fluororesin inside and on the surface of the capacitor element, T
The heat stress on the CNQ salt is reduced.

Further, when a thermosetting resin such as an epoxy resin is used for the outer package, the fluororesin has a property of repelling the outer package resin, so that the chemical and mechanical adverse effects of the outer package resin on the TCNQ salt are alleviated.

[0009]

EXAMPLES Examples of the present invention will be described below. FIG. 1 shows a capacitor element used in the present invention. First, a so-called etching treatment for increasing the effective surface area is performed by roughening a high-purity (99.99% or more) aluminum foil by a chemical treatment. Next, an oxide film (a thin film of aluminum oxide) is electrochemically formed on the surface of the aluminum foil in the electrolytic solution (chemical conversion treatment). Next, etching process,
The aluminum foil which has been subjected to the chemical conversion treatment is used as the anode foil 1, sandwiched between the counter cathode foil 2 and the manila paper as the separator 3 and wound into a cylindrical shape as shown in FIG. in this way,
The separator element 3 is wound between both electrode foils of the anode foil 1 and the cathode foil 2, which are formed by forming an oxide film on the aluminum foil, to form the capacitor element 6. In addition, 4 and 5 are lead wires.

Next, the capacitor element 6 is heat treated,
By carbonizing the manila paper forming the separator 3, the density is reduced due to the thinning of the fibers. As the separator, manila paper which has been carbonized by heat treatment at a predetermined temperature and time (for example, 240 ° C., 40 minutes) or a carbon nonwoven fabric is used, and is wound between the anode foil and the cathode foil. You can turn it.

Next, as shown in FIG. 2, metal (aluminum)
In case 7, a TCNQ salt, for example, an equivalent mixture of N, N-pentamethylene rutidinium ₂ · TCNQ ₄ and N-phenethyl rutidinium · TCNQ ₂ was heated and melted at 300 ° C., and preheated to the formation reaction. Insert the carbonized capacitor element 6, impregnate the molten TCNQ salt into the capacitor element 6, and quench.

Thereafter, perfluorocarbon, n-butylacetate, which has little chemical influence on the TCNQ salt,
A fluororesin having 1,1,1-trichloroethane or the like as a solvent is introduced into the capacitor element 6, and as shown in FIG.
A fluororesin coating film 9 is formed by volatilizing the solvent, and then an exterior material 10 such as an epoxy resin is applied to the exterior.
Finally, voltage processing (aging) is performed to complete the target capacitor. By using fine particles of 0.3 μm or less as the fluororesin,
This is effective because it can be introduced deep inside the capacitor element 6.

FIG. 4 shows a second embodiment, in which the exterior resin is 2
It has a layered structure, and 11 is a thermosetting resin such as a modified acrylic resin or urethane resin.

Further, FIG. 5 shows a third embodiment, and 12 is a polyester powder paint.

Table 1 shows a reflow test (160 ° C.) of a solid electrolytic capacitor according to the present invention and a conventional solid electrolytic capacitor, that is, a solid electrolytic capacitor manufactured without using a fluororesin, assuming heat at the time of soldering. In 2
It is the result of measuring the leakage current value before and after the reflow furnace for 30 minutes at 230 ° C.).

[0016]

[Table 1]

In Table 1, A to E are solid electrolytic capacitors according to the present invention, and F and G are solid electrolytic capacitors according to the prior art. The solid electrolytic capacitors of A to E according to the present invention have good results in leakage current characteristics after soldering.

[0018]

As described above, according to the present invention, a capacitor element in which an anode foil and a cathode foil are wound with a separator interposed therebetween, and a TCNQ which is cooled and solidified after impregnation of the capacitor element.
A solid electrolytic capacitor, which is composed of salt and fluororesin infiltrated into the inside of the capacitor element, has excellent leakage current characteristics even after soldering.

[Brief description of drawings]

FIG. 1 is a perspective view showing a capacitor element used in the present invention.

FIG. 2 is a sectional view of the solid electrolytic capacitor of the present invention.

FIG. 3 is a diagram showing a solid electrolytic capacitor of the present invention.

FIG. 4 is a diagram showing a second embodiment of the solid electrolytic capacitor of the present invention.

FIG. 5 is a diagram showing a third embodiment of the solid electrolytic capacitor of the present invention.

[Explanation of symbols]

 1 Anode foil 2 Cathode foil 3 Separator 4, 5 Lead wire 6 Capacitor element 7 Aluminum case 8 TCNQ salt 9 Fluororesin coating 10 Epoxy resin 11 Thermosetting resin 12 Polyester powder coating

Claims (5)

[Claims] 1. A capacitor element in which an anode foil and a cathode foil are wound via a separator, a TCNQ salt which is cooled and solidified after impregnating the capacitor element, and a fluororesin impregnated into the inside of the capacitor element. A solid electrolytic capacitor characterized in that. 2. The solid electrolytic capacitor according to claim 1, wherein the capacitor element is coated with a thermosetting resin. 3. The solid electrolytic capacitor according to claim 2, wherein the thermosetting resin has a two-layer structure of different resins. 4. The solid electrolytic capacitor according to claim 3, wherein the different type of resin is a one-component curing type epoxy resin containing a powder resin and a two-component mixing curing type or a latent curing agent. 5. The solid electrolytic capacitor according to claim 4, wherein the powder resin is a polyester-based powder coating material containing no volatile dispersant.