JPS63164420A - Electrolytic capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to electrolytic capacitors used in various electronic devices.

Prior Art A conventional aluminum electrolytic capacitor was constructed as shown in FIG. That is, after roughening high-purity aluminum foil to increase its surface area, an anode foil with a dielectric oxide film formed by anodizing and a cathode foil formed by roughening the aluminum foil are wound together with a separator. A capacitor element 1 was constructed by impregnating it with a driving electrolyte, and the capacitor element 1 was housed in a bottomed cylindrical case 2, and the open end of the case 2 was sealed with a sealing plate 3 to obtain a completed product.

Problems to be Solved by the Invention The separator used in such conventional aluminum electrolytic capacitors is made of manila paper or kraft paper, which is made of crossed cellulose. Therefore, the hole shape is curved, and the distance between the electrodes is long. In addition, the cellulose used for the separator has a density of 1.5 g/-, and the ones currently available have a porosity of about 50 to 65%, and products with higher porosity can be made up to about 73%. It is not uniform and cannot be put to practical use, and when the porosity becomes high, if the porosity is non-uniform, the variation in pore diameter becomes even larger, making it impossible to obtain stable characteristics.

The present invention is intended to eliminate the above-mentioned conventional drawbacks, and aims to provide an electrolytic capacitor with stable characteristics.

Means for Solving the Problems In order to solve the above problems, the present invention provides an anode foil made of a valve metal with an expanded surface area and an anodized film formed thereon, and a cathode foil opposite to the anode 8i foil. , a synthetic resin in which a large number of thick fibers are arranged at regular intervals in the width direction between the cathode foil and the anode foil, and fibers thinner than these thick fibers form a lattice so as to bridge the thick fibers. The anode foil and the cathode foil are stacked and wound so as to face each other with a separator made of a film in between to form a capacitor element.

Effect: With the above configuration, an electrolytic capacitor with stable characteristics can be obtained because the pore diameter of the separator is uniform.

Example Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 2 is a cylindrical case with a bottom made of metal such as aluminum, and l is an anode foil 6 made of a valve metal with an expanded surface area and an anodized film formed thereon, and an anode foil 6. 6 and a separator 8 made of a fluororesin microporous film having microscopic through holes interposed between the anode foil 6 and the cathode foil 7. A lead wire 9 is drawn out from this capacitor element 5. This capacitor element 5 is housed in a case 2, impregnated with a driving electrolyte, and a sealing body lO is assembled into the open end of the case 2. The opening end is sealed by drawing, and the lead wire 9 is drawn out from the sealing body 10 to the outside.

With such a configuration, the present invention has particularly studied the separator 8, and as shown in FIG. Use a stable separator.

Below, we will specifically compare conventional Manila paper, kraft paper, and fluororesin microporous films with large pore diameter variations, and electrolytic capacitors using the present invention's fluororesin microporous film with uniform pore diameter as a separator. This will be explained as an example.

Example 1 Next, Table 1 shows a comparison between an electrolytic capacitor using a separator according to an example of the present invention and an electrolytic capacitor using a conventional manila paper or kraft paper separator.

The product was measured at 6.3V and 100uF.

(Left below) As shown in Table 1, the electrolytic capacitor of the present invention has tanζ
In particular, the tanc value at low temperatures (-40°C) is about one-third that of Manila paper, which has excellent properties, and about one-half that of conventional synthetic fiber film. Even at 100 KHz (40° C.), the product of the present invention has an impedance that is about one-third that of Manila paper and about half that of conventional synthetic fiber film, so it can be said to be an extremely excellent capacitor. Furthermore, from the silate properties, it can be seen that the capacitor of the present invention has a significantly lower silt generation rate than that of conventional manila paper, and is approximately at the same level as that of conventional synthetic fiber film. Further, the frequency characteristics of this capacitor are shown in FIG. 3. As shown in FIG. 3, the impedance of the capacitor using the present invention is superior to that of manila paper or conventional synthetic fiber film at each frequency.

Note that FIG. 4 shows an enlarged view of the separator used in this example. FIG. 4A is a 100 times enlarged view of a conventional Mizuki separator, and FIG. 4B is a synthetic fiber film, "High Bore" (trade name) manufactured by Asahi Kasei Corporation. This is a 1000x magnification. FIG. 4C shows the synthetic fiber film separator used in the present invention, which is also a 1000x enlarged view.

As is clear from these figures, the conventional product (Fig. 4A) has extremely thick fibers and has been enlarged 100 times, and the present invention product (Fig.
The 10,000 times enlarged version of Figure 4C) appears to have approximately the same thickness. Moreover, when comparing the conventional product (FIG. 4B) and the product of the present invention (FIG. 4C), it can be seen that the product of the present invention has a lattice shape.

Effects of the Invention As described above, the electrolytic capacitor of the present invention is a capacitor with extremely excellent low loss, low impedance, temperature characteristics, and frequency characteristics.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of an electrolytic capacitor according to an embodiment of the present invention, Fig. 2 is a characteristic diagram showing the relationship between the number of holes in the separator and the pore diameter, Fig. 3 is a characteristic diagram showing the impedance-frequency characteristics, and Fig. 4 is a characteristic diagram showing the relationship between the number of holes and the diameter of the separator. Figures A, B, and C are enlarged views of separators, and Figure 5 is a sectional view of a conventional electrolytic capacitor. l...Capacitor element, 2...Case, 6...Positive foil, 7...Cathode foil, 8...
...Separator. Name of agent Patent attorney Toshio Nakao and two others Figure 1 Figure 2 Figure 3

Claims (5)

[Claims] (1) Between the anode foil made of a valve metal on which an anodized film is formed and the opposing cathode foil, there are many thick fibers at regular intervals in the width direction, and the fibers thinner than these thick fibers are An electrolytic capacitor in which the anode foil and the cathode foil are stacked and wound so as to face each other through a separator made of a synthetic resin film in which a lattice is formed so as to bridge thick fibers to form a capacitor element. (2) The diameter of the thick fibers of the separator is 0.1 to 0.5μ
2. The electrolytic capacitor according to claim 1, wherein the thin fibers have a diameter of 0.03 to 0.15 μm. (3) The electrolytic capacitor according to claim 2, wherein the separator has an average pore diameter of 0.1 to 0.3 μm. (4) The electrolytic capacitor according to claim 3, wherein the separator has a porosity of 65 to 75%. (5) The electrolytic capacitor according to claim 4, wherein the material of the separator is synthetic fiber such as polypropylene or polyethylene.