JPH0255931B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for manufacturing a flat capacitor element suitable for a flat electrode capacitor.

BACKGROUND TECHNOLOGY A conventional flat plate electrolytic capacitor has an outer case 2 formed into a flat plate shape as shown in FIG. A capacitor element 6 of the shape is mounted. Anode-side and cathode-side tabs 8 and 10 are pulled out from the end face of the capacitor element 6.
These tabs 8 and 10 are electrically connected to rivet terminals 12 and 14 inside the outer case 2 by crimping the rivet portions.

Conventionally, in an electrolytic capacitor using such a flat capacitor element, a wound type element or a non-wound type laminated element as shown in FIG. 9 has been used.

In the former type of wound element, the rolled anode and cathode electrode foils are wound together with separator paper into a cylindrical shape, and then bent in the diametrical direction to form a flat shape.

In the latter laminated type element, a plurality of rectangularly cut anode and cathode electrode foils are laminated alternately with separator paper, or strip-shaped anode and cathode electrode foils are alternately laminated with separator paper. It is folded in a zigzag manner and stacked to form a flat shape.

Furthermore, for such flat capacitor elements and their forming or electrode foil lamination,
There are the following problems.

(a) In such flat electrolytic capacitors, compared to conventional capacitors that use cylindrical capacitor elements that are not formed into flat shapes, the number of turns or degree of lamination of electrode foil is lower, increasing the capacitance of the capacitor element. In addition, it is necessary to increase the capacitance per unit area by using a high-magnification etching foil for the electrode foil.
Etched foils with high magnification have lower mechanical strength, and furthermore, a dielectric oxide film is formed on the electrode foil on the anode side due to chemical conversion, so it is not recommended to use such etched foils or their chemically formed foils. When a multi-layered element is formed by flattening or folding a rolled element, a considerably large stress is applied to the part that is bent during molding, causing cracks in the electrode foil, and dielectric oxidation. There is a risk of damaging the film. If such cracks or damage to the dielectric oxide film occur, problems such as an increase in leakage current and an electrical short circuit between electrode foils will occur.

(b) Therefore, in order to prevent cracks in the electrode foil and damage to the dielectric oxide film, there are
Considerable care is required, the process is complicated in manufacturing, and there are drawbacks such as poor yield.

(c) In addition, if the anode and cathode electrode foils cut into rectangular shapes and separator paper are alternately stacked on top of each other, the cracks that occur when forming a wound element flatly will not occur. However, in manufacturing, the process of alternately stacking electrode foils and separator paper is extremely troublesome, and there are disadvantages such as difficulty in mass production.

Therefore, rectangular anode or cathode electrode foils were arranged and fixed at regular intervals on the surface of a strip of separator paper, and then wound into a cylindrical shape.
A capacitor element manufacturing method has been proposed in which the separator paper is bent at the portions where the electrode foils on the anode side and the cathode side are not present, so that no bending stress is applied to the electrode foils.

Problems to be Solved by the Invention This method of bending the separator paper at the part where no electrode foil is present is advantageous in that no bending stress is applied to the electrode foil. is wound together with separator paper, and when the curved electrode foil is molded into a flat shape, molding stress is applied to prevent inconveniences such as cracking and damage to the dielectric oxide film on the anode side electrode foil. There is a risk that this may occur.

In addition, when a cylindrical wound element is formed into a flat shape, the separator paper on the inner surface has a different radius of curvature than that on the outer surface, so the outer separator paper and electrode foil may become loose or wrinkled. This causes problems such as uneven spacing between electrode foils and deterioration of electrical characteristics such as power loss and capacitance.

Therefore, this invention prevents stress from acting on the electrode foil during the process from winding to forming.
The purpose is to suppress cracks in the electrode foil and damage to the dielectric oxide film, as well as prevent loosening and wrinkling of the separator paper and electrode foil of the capacitor element, thereby improving electrical characteristics.

Means for Solving the Problems That is, the present invention has a strip-shaped separator paper with rectangular anode-side electrode foils arranged at regular intervals on the surface of the strip-shaped separator paper, and a strip-shaped cathode-side electrode foil;
Or, stack rectangular cathode side electrode foils arranged at regular intervals on another separator paper, and overlap the anode side electrode foil or the cathode side electrode foil formed into a rectangular shape in the area where the anode side electrode foil is not present. This is a method of setting the edges at the corners and winding them into a flat cylindrical shape.

Accordingly, in the present invention, a separator paper on which a rectangular anode-side or cathode-side electrode foil is arranged is wound flat in advance, and a portion of the separator paper where no electrode foil is present is wrapped around a corner. By forming a flat electrolytic capacitor element, the electrode foils on the anode side and the cathode side are maintained in a flat state, and molding stress is not applied to the electrode foils.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 to 4 show a first embodiment of the method for manufacturing a capacitor element of the present invention.

In FIG. 1, the winding frame 16 forming the capacitor element has two
Book support rods 20A and 20B are provided protrudingly, and a rotation shaft 22 is provided protrusively from the center of the support plate 18, and 24 is a fixed portion that is attached to a rotation drive portion (not shown).

Then, on the surface of the strip-shaped separator paper 26,
A plurality of rectangular anode-side electrode foils 28 are arranged at regular intervals, with their edges 29 overhanging the edges of the separator paper 26. Further, on the back side of the separator paper 26, a separator paper 32 is installed together with an electrode foil 30 on the cathode side.

In this case, the electrode foils 28 on the anode side and the cathode side,
The electrode foil 28 on the anode side is made of a film-forming metal such as aluminum, and is enlarged by etching.Furthermore, the electrode foil 28 on the anode side has a dielectric oxide film formed on the etched foil by chemical conversion. The etched foil is formed into a rectangular shape, or the etched foil is formed into a rectangular shape and a dielectric oxide film is formed by chemical conversion treatment. and,
The electrode foil 28 on the anode side is attached to the surface of the separator paper 26 using an adhesive such as polyvinyl alcohol. At that time, tabs 3 for terminal connection are attached to the electrode foils 28 and 30 on the anode side and the cathode side.
6 and 38 shall be electrically connected by crimping.

In this way, the separator paper 26 to which the electrode foil 28 on the anode side is attached, the electrode foil 30 on the cathode side, and the separator paper 32 are stacked one on top of the other, and are hung around the support rods 20A and 20B of the winding frame 16 to move the winding frame 16 along the arrow A. By rotating in the direction, a flat wound capacitor element 40 is obtained.

In this case, a portion of the separator paper 26 where the electrode foil 28 on the anode side does not exist is set on the support rods 20A, 20B of the winding frame 16, and the electrode foil 28 on the anode side is positioned between the support rods 20A, 20B. This prevents bending stress from acting on the electrode foil 28 on the anode side.

FIG. 2 shows a capacitor element 40 obtained by such a winding process, and the part where the electrode foil 28 on the anode side is not present is selected as the bent corner, and the arrows B, C, D, and E By applying molding pressure from the direction, a flat capacitor element 40 is obtained as shown in FIG.

In this case, the edge 29 of the electrode foil 28 on the anode side protruding from one end surface of the capacitor element 40
As shown in FIG. 4, the electrode foils 28 on each anode side are electrically connected by welding while applying pressure in the directions indicated by arrows F and G.

After winding the electrode foils 28, 30 and the separator papers 26, 32 in this way, if they are formed, the electrode foil 28 on the anode side, on which the dielectric oxide film has been formed by the chemical conversion treatment, will be etched after high-magnification etching treatment. The effect of bending stress can be minimized, preventing cracks caused by bending of the foil itself and damage to the dielectric oxide film, as well as preventing damage to the dielectric oxide film, which can occur when forming a conventional wound type element into a flat shape. It is possible to remove looseness and wrinkles, suppress power loss and changes in capacitance, and realize stable electrical characteristics. In particular, during manufacturing, handling in the process, which previously required considerable care such as bending, becomes easier, and it is expected that manufacturing time will be shortened.

In addition, since the electrode foil 28 on each anode side is electrically connected by welding its edges, it has excellent electrical characteristics such as a lower resistance value than when a strip-shaped one is used, and for example, a reduction in power loss. This can be expected to reduce high-frequency impedance.

5 and 6 show a second embodiment of the method for manufacturing a capacitor element according to the present invention, and the same parts as in the embodiment shown in FIG. 1 are given the same reference numerals.

In the first embodiment, the flat capacitor element 40 was formed using the winding frame 16, and the capacitor element 40 was removed from the winding frame 16 to form an element similar to a conventional wound type element. In the example, as shown in FIG. 5, instead of the winding frame 16, a plate-shaped winding core 42 is provided with a separator paper 26, an electrode foil 28 attached to the anode side, an electrode foil 30 on the cathode side, and a separator paper. 32 are overlapped and wound in the direction of arrow H to form a capacitor element 40.

FIG. 6 shows a capacitor element 40 obtained using the winding core 42. Even when the winding core 42 is used in this manner, a similar flat capacitor element 40 can be formed, and when the winding core 42 is left in the capacitor element 40, bending of the capacitor element 40 can be prevented. In this case, the core 42 is cut to the width of the capacitor element 40. Also,
When the winding core 42 is removed from the capacitor element 40, the capacitor element 40 can be formed more flat.

In the first and second embodiments, only the electrode foil 28 on the anode side was formed into a rectangular shape and placed on the surface of the separator paper 26, but other separator paper 3
A similar capacitor can be obtained by winding a plurality of rectangular cathode electrode foils 30 arranged in the same manner as the anode electrode foil 28 on the surface of the electrode foil 28 on the anode side. An element is obtained.

In this case, as shown in FIG. 7, the edges 29, 31 of the electrode foils 28, 30 on the anode side and the cathode side are
The tabs 36 of each electrode foil 28, 30 protrude from the opposite edge of the separator paper 26, 32,
Connect capacitor element 4 so that 38 also has the same polarity.
0 from the opposite side, and weld the edges 29, 31 of each electrode foil 28, 30 and the tabs 36, 38 with the same polarity while applying pressure from the directions of arrows I, J, K, and L.
Connect electrically.

In this way, damage such as cracks to the electrode foil 30 on the cathode side can be prevented, and the electrical characteristics can be improved.

Effects of the Invention As explained above, according to the present invention, the following effects can be obtained.

(a) It is possible to form a flat capacitor element while maintaining the electrode foil on the anode side as a flat plate, and it is possible to avoid bending stress on the electrode foil on the anode side, which prevents cracks due to bending etc. In addition to preventing damage to the dielectric oxide film and dielectric oxide film, it also prevents loosening and wrinkling of the electrode foil and separator paper, which were caused by conventional winding or forming processes, and reduces power loss and static electricity. It is possible to prevent deterioration of electrical characteristics such as changes in capacitance.

(b) The electrode foil on the cathode side is similar to the electrode foil on the anode side.
By forming them into rectangular shapes and placing them on separator paper at regular intervals, it is possible to form a capacitor element by bending only the separator paper, and it is also possible to prevent the occurrence of cracks in the electrode foil on the cathode side.

(c) In particular, bending of the electrode foil on the anode side or the cathode side can be avoided, making it easier to handle in the capacitor element molding process, increasing processing efficiency, and reducing manufacturing costs.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing a capacitor element in the winding process in the first embodiment of the capacitor element manufacturing method of the present invention, FIG. 2 is a side view of the capacitor element showing the forming process, and FIG. FIG. 4 is a perspective view showing a flat capacitor element, FIG. 4 is a sectional view taken along the - line in FIG. FIG. 6 is an explanatory diagram showing the end surface of a capacitor element, FIG. 7 is an explanatory diagram showing the welded part of the end surface, and FIG. 8 is a perspective view showing a general flat electrolytic capacitor. , No. 9
The figure is a perspective view showing a conventional flat capacitor element. 16... Winding frame, 20A, 20B... Support rod, 2
6...Separator paper, 28...Anode side electrode foil,
30... Electrode foil on the cathode side, 32... Separator paper.

Claims (1)

[Claims] 1. Anode side electrode foils formed into a rectangular shape are arranged at regular intervals on the surface of a band-shaped separator paper, and a band-shaped cathode side electrode foil or a rectangular shape is formed on another separator paper. The electrode foils on the cathode side, which are formed into a rectangular shape, are placed one on top of the other and arranged at regular intervals, and the part where the electrode foil on the anode side or the electrode foil on the cathode side, which is formed into a rectangular shape, is not present is set at the corner and flattened. A method for manufacturing a capacitor element, characterized by winding it into a cylindrical shape. 2 The above-mentioned winding process includes two windings arranged at regular intervals.
2. The method for manufacturing a capacitor element according to claim 1, wherein the method is carried out using a winding frame made of a book support rod. 3. The method for manufacturing a capacitor element according to claim 1, wherein the winding process is performed using a plate-shaped winding core.