JPH0257327B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a method for manufacturing an electrolytic capacitor element having a wound structure.

[Conventional technology]

Electrolytic capacitors with a wound structure use a band-shaped film-forming metal foil such as aluminum as an electrode, and an oxide film formed on the surface of this film as a dielectric is used as an anode. A cylindrical capacitor element is produced by wrapping the cathode foil overlappingly with the foil, impregnating it with electrolyte, and storing it in an exterior case.

Since the capacitance of an electrolytic capacitor is proportional to the surface area of the anode, the surface of the anode is enlarged by etching in order to increase the capacitance per unit volume.

In recent years, due to the demand for smaller electrolytic capacitors,
Etching for this purpose of enlarging the surface area has become extremely sophisticated.

As a result, the number of holes in the electrode foil increases due to etching, and as a result, the mechanical strength of the electrode foil with respect to bending, tension, etc. is significantly reduced.

FIG. 2 shows a conventional method of winding an electrolytic capacitor element, in which the element is wound around the winding shaft 4 once or several times in advance. Insert the winding start end 5 of the anode foil 1 between the cathode foil 2 and two of the two separator papers 3, and then insert the end 5 of the anode foil 1 along with the cathode foil 2 and separator paper 3 in the direction indicated by the arrow a in the figure. A capacitor element is formed by winding in the direction of .

At this time, the tip 5 of the anode foil 1 is linear, and when the tip 5 is sandwiched between the separator paper 3 and rapidly tightened in a spiral, the anode foil 1 becomes brittle at the beginning of this winding. This will cause the foil to break at the end 5.

For this reason, the sharp end of the broken anode foil 1 pierces the separator paper 3, resulting in a short circuit with the cathode foil 2.

[Problem that the invention seeks to solve]

This invention improves on these conventional drawbacks by winding an etched anode foil with low mechanical strength to form a capacitor element without inconveniences such as breakage, thereby creating a highly reliable electrolytic capacitor. The purpose is to obtain.

[Means for solving problems]

The method of the present invention is a method for manufacturing an electrolytic capacitor element in which a band-shaped film-forming metal foil, which has been subjected to surface enlargement treatment by etching and has a dielectric oxide film layer formed on its surface, is wound as an anode. Winding is performed after the winding start end of the anode is previously bent into a circular arc having a curvature equivalent to that of the winding portion.

This invention will be explained in detail below.

〔Example〕

FIG. 1 shows an embodiment of this invention.
A cathode foil 2 and two separator papers 3 are stacked on the winding shaft 4 so as to sandwich the cathode therebetween, and are previously wrapped once or several times.

Then, the end 6 of the anode foil 1, which has been etched and has a dielectric oxide layer formed thereon, is inserted into the upper surface of the separator paper 3 in the direction of arrow b in the figure, and the separator paper 3 and the cathode Together with the foil 2, it is wound in multiple layers in the direction of arrow a in the figure.

At this time, the winding start end 6 of the anode foil 1 is
From its tip, an arc is formed with a curvature approximately equal to that of the arc being wound around.

To form this arc, for example, as shown in FIG. is pressed from above so as to sandwich the anode foil 1 between the fixed shaft 7, and then the rubber roller 8 is pressed against the fixed shaft 7.
While pressing the anode foil 1 until it comes to the side of the anode foil 1, rotate it as shown by the arrow c in the figure.

In this manner, the wound capacitor element is impregnated with an electrolytic solution by a known method (not shown), provided with electrode extraction means, and housed in an exterior case and sealed to become an electrolytic capacitor.

[Effect]

In the capacitor element of the present invention wound by such a method, the winding start end of the anode foil 1 is bent into a circular arc with a curvature close to the circular arc of the winding shaft. No unreasonable stress is applied and the anode foil 1 does not break.

〔effect〕

As described above, according to the present invention, even if the electrode foil is highly etched and has low mechanical strength, it is possible to form a wound element without causing breakage, thereby preventing short circuit accidents. A highly reliable electrolytic capacitor can be obtained.

Furthermore, since it is possible to wind electrode foil with a high etching ratio, which was conventionally impossible to wind, the capacitance per unit volume can be increased, contributing to miniaturization of electrolytic capacitors.

Furthermore, since the occurrence of short circuit accidents is reduced and the yield in the manufacturing process is improved, it is useful as a method for manufacturing electrolytic capacitor elements.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the method of winding an electrolytic capacitor element of the present invention, Fig. 2 is a cross-sectional view showing a conventional method of winding a capacitor element, and Fig.
The figure is an explanatory diagram showing a method of bending the tip of an anode foil according to the present invention. DESCRIPTION OF SYMBOLS 1... Anode foil, 2... Cathode foil, 3... Separator paper, 4... Winding shaft, 5, 6... End portion, 7... Fixed shaft, 8... Rubber roller.

Claims (1)

[Scope of Claims] 1. A method for manufacturing an electrolytic capacitor element in which a band-shaped film-forming metal foil, which has been subjected to surface enlargement treatment by etching and has a dielectric oxide film layer formed on its surface, is wound as an anode. A method for manufacturing an electrolytic capacitor element, characterized in that the winding start end of the anode is bent in advance into a circular arc having a curvature equivalent to the circular arc of the winding portion, and then winding is performed. 2 The winding start end of the anode is bent by placing the anode end on a fixed shaft having approximately the same diameter as the winding arc, pressing the anode end with a rotatable rubber roller from the top surface, and then moving the rubber roller along the fixed shaft. Claim 1, which is performed by rotating the
A method for manufacturing an electrolytic capacitor element as described in .