CN114724857A - Aluminum electrolytic capacitor based on sintered aluminum foil and preparation method thereof - Google Patents

Abstract

An aluminum electrolytic capacitor based on sintered aluminum foil, comprising a core pack and a casing, the core pack is sealed and arranged in the casing; the core pack includes an anode foil, an electrolytic paper and a cathode foil, and the electrolytic paper is arranged between the anode foil and the cathode foil; the core pack The electrolyte is impregnated on it, the anode foil is a sintered aluminum foil, and the sintered aluminum foil includes a substrate and aluminum powder or aluminum alloy powder sintered on the substrate. In the present invention, the winding radius of the core package at the initial stage of winding is increased by the setting of the winding drum, so as to ensure that the sintered aluminum foil will not be cracked during winding and thus cause leakage current; at the same time, the sintered aluminum foil in the present invention The oxide film can be made thicker than that of conventional etched foils to increase the withstand voltage.

Description

A kind of aluminum electrolytic capacitor based on sintered aluminum foil and preparation method thereof

technical field

The invention relates to an aluminum electrolytic capacitor, in particular to an aluminum electrolytic capacitor based on sintered aluminum foil and a preparation method thereof.

Background technique

The thickness of the oxide film on the surface of the anode foil of the medium and high voltage aluminum electrolytic capacitor is relatively thick, which leads to the fact that the groove formed on the surface of the anode foil by traditional etching cannot be too small, otherwise the oxide film generated in the subsequent forming process will These trenches are filled, so generally the capacitance of medium and high voltage aluminum electrolytic capacitors is not high.

In order to solve this situation, Japan's Toyo Aluminum Co., Ltd. has disclosed a scheme for sintering aluminum foil, such as patent 2008801287834, an electrolytic material for aluminum electrolytic capacitors and a method for manufacturing the electrode material; the anode foil disclosed in this patent uses The aluminum powder or aluminum alloy powder is sintered on the substrate, thereby increasing the surface area of the anode foil. Since the aluminum powder or aluminum alloy powder is sintered on the substrate, the oxide film formed on the aluminum powder or aluminum alloy powder has a great influence on the porosity. small, thereby increasing the capacitance of the capacitor.

The anode foil disclosed by Japan's Toyo Aluminum Co., Ltd. is aluminum powder or aluminum alloy powder is sintered on the substrate, which makes the anode foil not resistant to bending. Cracks occur, especially on the anode foil in the innermost circle of the core package. Therefore, sintered aluminum foil is generally used in multilayer capacitors; however, the manufacturing difficulty and cost of multilayer capacitors are higher than those of traditional aluminum electrolytic capacitors.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an aluminum electrolytic capacitor based on sintered aluminum foil capable of increasing capacitance and a preparation method thereof

In order to solve the above-mentioned technical problems, the technical solution proposed by the present invention is: an aluminum electrolytic capacitor based on sintered aluminum foil, comprising a core package and an outer shell, the core package is sealed and arranged in the outer shell; the core package includes anode foil, electrolytic paper and cathode foil, the electrolytic paper is arranged between the anode foil and the cathode foil; the core pack is impregnated with electrolyte, the anode foil is a sintered aluminum foil, and the sintered aluminum foil includes a substrate and aluminum powder or aluminum sintered on the substrate alloy powder.

In the above-mentioned aluminum electrolytic capacitor based on sintered aluminum foil, preferably, the core package is formed by winding anode foil, electrolytic paper and cathode foil; an insulating winding drum is provided in the center of the core package, and the anode foil, electrolytic The paper and cathode foil are wound on a spool.

In the above-mentioned aluminum electrolytic capacitor based on sintered aluminum foil, preferably, at least one layer of electrolytic paper is wound on the winding drum.

In the above-mentioned aluminum electrolytic capacitor based on sintered aluminum foil, preferably, an anode foil guide strip and a cathode foil guide strip are respectively provided on the anode foil and the cathode foil, and the anode foil guide strip and the cathode foil guide strip are respectively electrically connected to each other. on the anode and cathode feet.

In the above-mentioned aluminum electrolytic capacitor based on sintered aluminum foil, preferably, the electrolytic paper protrudes from the upper end of the core pack by 0.5-2 mm.

A preparation method of an aluminum electrolytic capacitor based on sintered aluminum foil, comprising the following steps,

1) Sleeve the winding cylinder on the winding needle of the nail rolling machine and fix it;

2) The anode foil, electrolytic paper and cathode foil are wound on the winding drum to form a core pack, and the electrolytic paper at the upper end and/or the lower end of the core pack is protruded by 0.5-2mm; the anode foil is a sintered aluminum foil, and the sintered aluminum foil includes a matrix and aluminum powder or aluminum alloy powder sintered on the substrate;

3) The core contains immersion electrolyte;

4) Electrically connect the anode foil and cathode foil on the anode foil and the cathode foil to the anode pin and the cathode pin respectively;

5) Seal the core package of step 4) in the outer casing.

In the above-mentioned preparation method of aluminum electrolytic capacitor based on sintered aluminum foil, preferably, in the step 2), before winding the anode foil and the cathode foil, the electrolytic paper is firstly wound on the winding drum so that the core package has a diameter of 1-3 mm paper core.

In the above-mentioned preparation method of an aluminum electrolytic capacitor based on sintered aluminum foil, preferably, in the step 3) impregnation with the electrolyte, heating impregnation, vacuum impregnation or pressure impregnation can be used.

In the present invention, the sintered aluminum foil can adjust the size of the voids on the sintered aluminum foil to a certain extent by adjusting the particle size of the aluminum powder and the aluminum alloy powder. Therefore, the oxide film on the sintered aluminum foil in the present invention can be made thicker than that of the conventional etched foil to increase the withstand voltage value.

Compared with the prior art, the advantages of the present invention are: in the present invention, the winding radius of the core package at the initial stage of winding is increased by the arrangement of the winding drum, so as to ensure that the sintered aluminum foil will not be cracked during the winding process. Leakage current is generated.

Description of drawings

FIG. 1 is a schematic structural diagram of the core package unfolding in Example 1. FIG.

illustration

1. Winding drum; 2. Anode foil; 3. Electrolytic paper; 4. Cathode foil; 5. Anode foil; 6. Cathode foil.

Detailed ways

In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and in detail below with reference to the preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

It should be noted that when an element is described as being "fixed, fixed, connected or connected to" another element, it can be directly fixed, fixed, connected or connected to the other element , or it can be indirectly fixed, fixed, connected or communicated with another element through other intermediate connectors.

Unless otherwise defined, all technical terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the protection scope of the present invention.

Example 1

An aluminum electrolytic capacitor based on sintered aluminum foil, the diameter of the capacitor shell is 42mm (Φ42), and the rated voltage is 315V; it includes a core package and a shell, the core package is sealed and arranged in the shell through a cover plate, and the diameter of the core package is about 41mm. The core pack includes an anode foil 2, an electrolytic paper 3 and a cathode foil 4, and the electrolytic paper 3 is arranged between the anode foil 2 and the cathode foil 4; the core pack is impregnated with electrolyte, the anode foil 2 is a sintered aluminum foil, and the sintered aluminum foil includes The base body and the aluminum alloy powder sintered on the base body, the aluminum alloy powder is aluminum-magnesium alloy powder, the weight of aluminum accounts for 80%-90% of the total weight, and the weight of magnesium accounts for 10%-20% of the total weight. In this embodiment, after the aluminum-magnesium alloy powder is sintered onto the substrate, the porosity of the entire sintered aluminum foil is about 35%.

In this embodiment, as shown in FIG. 1 , the core package is formed by winding the anode foil 2, the electrolytic paper 3 and the cathode foil 4; the center of the core package is provided with an insulating winding drum 1, the anode foil 2, the electrolytic paper 3 and the cathode foil 4 are wound. The paper 3 and the cathode foil 4 are wound on the winding drum 1, and the diameter of the winding drum 1 is about 5.5 mm. A layer of electrolytic paper 3 is wound on the winding drum 1, and a layer of electrolytic paper 3 is first wound on the winding drum 1 to prevent the anode foil 2 or the cathode foil 4 from being directly wound on the winding drum 1, so as to prevent the anode foil 2 or the cathode foil 4 from being directly wound on the winding drum 1. The foil 2 or the cathode foil 4 has an influence, especially on the anode foil 2 . The material of the reel 1 is the same or close to the material of the electrolytic paper 3. It is better that the winding surface of the reel 1 is soft; the reel 1 must be insulated, because the voltage of the capacitor is relatively high when it is practical 2 is in electrical communication with the casing through the winding drum 1 .

In this embodiment, as shown in FIG. 1 , the anode foil 2 and the cathode foil 4 are respectively provided with an anode foil guide strip 5 and a cathode foil guide strip 6 , and the anode foil guide strip 5 and the cathode foil guide strip 6 are respectively riveted to the cover. on the anode and cathode pins on the board. The electrolytic paper 3 protrudes from the upper end of the core pack by 0.5-2mm, so that there will be a safe distance between the anode foil 5 on the anode foil 2 and the cathode foil 4 of the core pack. produced by the electrolytic paper 3; similarly, there is also a safe distance between the cathode foil 4 and the anode foil 2 of the core pack.

The aluminum electrolytic capacitor of this embodiment is a medium and high voltage aluminum electrolytic capacitor, and its rated voltage is 315V; since the anode foil 2 in this embodiment uses sintered aluminum foil, it is not necessary to etch the anode foil 2 to increase the surface area; because this embodiment The aluminum-magnesium alloy powder sintered on the anode foil 2 of the example has a strong void structure, and its surface area itself is large. Of course, in this embodiment, it is also possible to etch the anode foil 2, but the acid used for etching will affect the aluminum-magnesium alloy powder sintered on the substrate, thereby reducing the bonding strength between the aluminum-magnesium alloy powders.

This embodiment also provides a preparation method of an aluminum electrolytic capacitor based on sintered aluminum foil, comprising the following steps:

1) Sleeve the winding drum 1 on the winding needle of the nail rolling machine and fix it;

2) The anode foil 2, the electrolytic paper 3 and the cathode foil 4 are wound on the winding drum 1 to form a core package, and the electrolytic paper 3 at the upper end of the core package is protruded by 0.5-2mm; the anode foil 2 is a sintered aluminum foil, which is a sintered aluminum foil. It includes a base body and aluminum powder or aluminum alloy powder sintered on the base body. Before winding the anode foil 2 and the cathode foil 4, the electrolytic paper is wound on the winding drum 1, so that the core pack produces a paper core with a diameter of about 2 mm. In this embodiment, the paper core is composed of electrolytic paper.

3) The core contains impregnated electrolyte; the method of vacuum impregnation is adopted when impregnating the electrolyte; because the anode foil 2 is a sintered aluminum foil with more voids, it can impregnate more electrolyte and the higher viscosity electrolyte is It is relatively easy to impregnate into the core package.

4) Electrically connect the anode foil 5 and the cathode foil 6 on the anode foil 2 and the cathode foil 4 to the anode pin and the cathode pin of the cover plate respectively;

5) The core package of step 4) is sealed in the casing through the cover plate.

In this embodiment, some capacity will be lost due to the existence of the winding drum 1, because less anode foil 2 will be wound by the core package of the same diameter, but since the anode foil 2 in this embodiment uses sintered aluminum foil, the sintered aluminum foil itself The strong void structure can greatly increase the surface area of the anode foil 2, which can greatly increase the capacity of the capacitor, especially for the capacitance of medium and high voltage capacitors.

Comparative Example 1

In Comparative Example 1, the conventional etched anode foil 2 is used, and the winding drum 1 is not provided inside the core package. The anode foil 2, the electrolytic paper 3 and the cathode foil 4 are directly wound, and the diameter of the core package is also 41mm or so. The other parts of Comparative Example 1 are the same as those of Example 1.

20 products of Example 1 and Comparative Example 1 were selected respectively, and the tests of capacitance and withstand voltage were carried out respectively, and the average results were as follows:

serial number Average capacitance (μF) Average withstand voltage (V) Example 1 47.3 368.2 Comparative Example 1 43.8 329.6

It can be seen from the above table that the average capacitance of Example 1 does not increase much compared to that of Comparative Example 1. This is because the winding drum 1 in Example 1 occupies a certain amount of space, so that the length of the anode foil 2 is not as long as that of the anode in Comparative Example 1. The length of the foil 2 is large; however, the withstand voltage value in Example 1 is significantly higher than that in Comparative Example 1. This is because the oxidation of the surface of the anode foil 2 cannot be carried out during chemical formation in Comparative Example 1. If the film thickens too much, too much oxide film will block the grooves on the anode foil 2 .

Claims (8)

1. An aluminum electrolytic capacitor based on sintered aluminum foil comprises a core bag and a shell, wherein the core bag is hermetically arranged in the shell; the core package comprises an anode foil, an electrolytic paper and a cathode foil, wherein the electrolytic paper is arranged between the anode foil and the cathode foil; the method is characterized in that: the core bag contains electrolyte, the anode foil is a sintered aluminum foil, and the sintered aluminum foil comprises a substrate and aluminum powder or aluminum alloy powder sintered on the substrate.

2. The aluminum electrolytic capacitor based on sintered aluminum foil as recited in claim 1, wherein: the core package is formed by winding anode foil, electrolytic paper and cathode foil; the core bag is characterized in that an insulating winding drum is arranged in the center of the core bag, and the anode foil, the electrolytic paper and the cathode foil are wound on the winding drum.

3. The aluminum electrolytic capacitor based on sintered aluminum foil as recited in claim 2, wherein: at least one layer of electrolytic paper is wound on the winding drum.

4. The aluminum electrolytic capacitor based on sintered aluminum foil as recited in claim 1, wherein: and the anode foil and the cathode foil are respectively provided with an anode foil guiding strip and a cathode foil guiding strip which are respectively and electrically connected to the anode pin and the cathode pin.

5. The aluminum electrolytic capacitor based on sintered aluminum foil as recited in claim 1, wherein: the electrolytic paper extends out of the upper end of the core bag by 0.5-2 mm.

6. A preparation method of an aluminum electrolytic capacitor based on a sintered aluminum foil is characterized by comprising the following steps: comprises the following steps of (a) carrying out,

1) sleeving a winding cylinder on a winding needle of a coil nailing machine and fixing;

2) winding the anode foil, the electrolytic paper and the cathode foil on a winding drum to form a core package, wherein the electrolytic paper at the upper end and/or the lower end of the core package extends out 0.5-2 mm; the anode foil is a sintered aluminum foil which comprises a substrate and aluminum powder or aluminum alloy powder sintered on the substrate;

3) the core bag is impregnated with electrolyte;

4) electrically connecting the anode foil strip and the cathode foil strip on the anode foil and the cathode foil to the anode terminal and the cathode terminal respectively;

5) hermetically arranging the core package of the step 4) in the shell.

7. The method for manufacturing an aluminum electrolytic capacitor based on a sintered aluminum foil as recited in claim 6, wherein: in the step 2), before winding the anode foil and the cathode foil, the electrolytic paper is wound on a winding drum so that the core package generates a paper inner core with the diameter of 1-3 mm.

8. The method for manufacturing an aluminum electrolytic capacitor based on a sintered aluminum foil as recited in claim 6, wherein: the impregnation electrolyte in the step 3) can adopt heating impregnation, vacuum impregnation or pressure impregnation.

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