Aluminum electrolytic capacitor anode foil and aluminum electrolytic capacitor

Abstract

The present invention provides an anode foil of an aluminum electrolytic capacitor, including an anode foil pretreated with a treatment liquid, wherein the treatment liquid includes a silicon compound, a solvent and an additive, and the additive includes one or more of boric acid, mannitol and sebacic acid, so that the silicon content on the anode foil is 50 to 1000 ppm. The present invention also provides a method for preparing the anode foil of an aluminum electrolytic capacitor and an aluminum electrolytic capacitor. The anode foil provided by the present invention is infiltrated with the treatment liquid, which can improve the withstand voltage of the anode foil, reduce the leakage current of the capacitor, reduce the gas production of the capacitor during aging, and extend the capacitor service life of the anode foil.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum electrolytic capacitors, and in particular relates to an aluminum electrolytic capacitor anode foil and an aluminum electrolytic capacitor. Background Art

[0002] Aluminum electrolytic capacitors are one of the three most important components, which can realize functions such as filtering, bypassing, coupling and energy storage in the circuit. With the continuous progress and development of the electronics industry, the performance requirements for capacitors are getting higher and higher, mainly reflected in the requirements of long life, high voltage resistance, low leakage current and low gas production. Improving the performance of anode foil is crucial to improving the relevant performance of aluminum electrolytic capacitors. The existing method of improving the performance of anode foil is to introduce silicon dioxide with high dielectric properties into the composite film on the surface of the anode foil, thereby improving the dielectric properties of the composite film and improving the withstand voltage strength. However, if only silicon dioxide is added to the electrolyte, the prepared capacitor still faces the problems of low withstand voltage, high leakage current and short service life. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an aluminum electrolytic capacitor anode foil and an aluminum electrolytic capacitor in view of the problems in the prior art of low anode foil withstand voltage, high leakage current and short life of capacitors using the anode foil.

[0004] The technical solution adopted by the present invention to solve the above problems is as follows:

[0005] In a first aspect, the present invention provides an aluminum electrolytic capacitor anode foil, comprising:

[0006] Anode foil pretreated with a treatment solution;

[0007] The treatment liquid includes a silicon compound, a solvent and an additive;

[0008] The additives include one or more of boric acid, mannitol and sebacic acid;

[0009] The silicon content on the anode foil is 50-1000 ppm.

[0010] Optionally, based on the total weight of the treatment liquid being 100%, the content of the silicon compound is 2% to 30%, the content of the solvent is 60% to 96%, and the content of the additive is 2% to 10%.

[0011] Optionally, based on the total weight of the treatment liquid being 100%, the content of the silicon compound is 5% to 20%, the content of the solvent is 72% to 90%, and the content of the additive is 5% to 8%.

[0012] Optionally, the silicon compound includes one or more of silicon oxide, silicic acid and silicate.

[0013] Optionally, the silicon oxide is silicon dioxide, and the silicate includes sodium silicate and potassium silicate.

[0014] Optionally, the solvent includes one or two of water and a mixed solvent consisting of water and an organic polar solvent;

[0015] The organic polar solvent includes ethylene glycol and diethylene glycol.

[0016] The invention provides an anode foil soaked in a treatment liquid. The treatment liquid uses a silicon compound as a solute, and adds one or more of boric acid, mannitol and sebacic acid as additives and a solvent, so that the silicon content on the anode foil is 50-1000 ppm. The inventor unexpectedly found that the introduction of boric acid, mannitol and sebacic acid into the treatment liquid soaked in the anode foil causes a dense silicon-containing layer to adhere to the anode foil, thereby improving the withstand voltage of the anode foil, reducing the leakage current of the capacitor and extending the service life of the capacitor using the anode foil of the invention.

[0017] In a second aspect, the present invention further provides a method for preparing the anode foil as described above, comprising the following steps:

[0018] Cutting the foil according to the required size of the capacitor to obtain a first anode foil;

[0019] immersing the first anode foil in a treatment solution and drying to obtain the anode foil;

[0020] The treatment liquid includes a silicon compound, a solvent and an additive;

[0021] The additives include one or more of boric acid, mannitol and sebacic acid;

[0022] The silicon content on the anode foil is 50-1000 ppm.

[0023] Since the cut aluminum foil lacks an oxide film and an insulating film on the side, the anode foil provided by the present invention is obtained by cutting the aluminum foil into a first anode foil of suitable size according to the requirements of the capacitor. The first anode foil is pre-treated by immersing in a treatment solution, wherein the treatment solution includes a silicon compound, a solvent and an additive, and the additive includes one or more of boric acid, mannitol and sebacic acid, so that the silicon content on the anode foil is 50 to 1000 ppm. The silicon-containing film is repaired by the treatment solution to fill the missing silicon film, thereby improving the withstand voltage of the anode foil, reducing the leakage current of the capacitor, reducing the gas production of the capacitor during aging, and extending the service life of the capacitor using the anode foil of the present invention.

[0024] In a third aspect, the present invention further provides an aluminum electrolytic capacitor, comprising a capacitor element, an electrolyte and an electrolyte solution, wherein the capacitor element comprises a cathode foil, a diaphragm and the anode foil as described above, wherein the diaphragm is located between the cathode foil and the anode foil. DETAILED DESCRIPTION

[0025] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] The technical solution adopted by the present invention to solve the above problems is as follows:

[0027] The present invention provides an aluminum electrolytic capacitor anode foil, comprising:

[0028] Anode foil pretreated with a treatment solution;

[0029] The treatment liquid includes a silicon compound, a solvent and an additive;

[0030] The additives include one or more of boric acid, mannitol and sebacic acid;

[0031] The silicon content on the anode foil is 50-1000 ppm.

[0032] The present invention provides an anode foil pretreated with a treatment liquid, wherein the treatment liquid uses a silicon compound as a solute, and one or more of boric acid, mannitol and sebacic acid are added as additives and a solvent, so that the silicon content on the anode foil is 50-1000 ppm. The inventor unexpectedly discovered that the introduction of boric acid, mannitol and sebacic acid into the treatment liquid in which the anode foil is soaked causes a dense silicon-containing layer to adhere to the anode foil, thereby improving the withstand voltage of the anode foil, reducing the leakage current of the capacitor, reducing the gas generation of the capacitor due to aging, and extending the service life of the capacitor using the anode foil of the present invention.

[0033] In some embodiments of the present invention, based on the total weight of the treatment liquid being 100%, the content of the silicon compound is 2% to 30%, the content of the solvent is 60% to 96%, and the content of the additive is 2% to 10%.

[0034] Controlling the content of silicon compounds within the range of 2% to 30% can effectively improve the withstand voltage of the anode foil, significantly increase the service life of the capacitor and reduce leakage current. If the content of silicon compounds is greater than 30%, the capacitance attenuation of the capacitor will increase, thereby reducing the service life of the capacitor.

[0035] In some embodiments of the present invention, based on the total weight of the treatment liquid being 100%, the content of the silicon compound is 5% to 20%, the content of the solvent is 72% to 90%, and the content of the additive is 5% to 8%.

[0036] In some embodiments of the present invention, the silicon compound includes one or more of silicon oxide, silicic acid and silicate.

[0037] The silicon-containing compound is added to the treatment solution, and the anode foil is pretreated with the treatment solution; since the silicon-containing compound has high dielectric properties, the compressive strength of the anode foil is increased.

[0038] In some embodiments of the present invention, the silicon oxide is silicon dioxide, and the silicate includes sodium silicate and potassium silicate.

[0039] In some embodiments of the present invention, the solvent includes one or two of water and a mixed solvent consisting of water and an organic polar solvent;

[0040] The organic polar solvent includes ethylene glycol and diethylene glycol.

[0041] The present invention also provides a method for preparing the anode foil as described above, comprising the following steps:

[0042] Cutting the foil according to the required size of the capacitor to obtain a first anode foil;

[0043] immersing the first anode foil in a treatment solution and drying to obtain the anode foil;

[0044] The treatment liquid includes a silicon compound, a solvent and an additive;

[0045] The additives include one or more of boric acid, mannitol and sebacic acid.

[0046] Since the cut aluminum foil lacks an oxide film and an insulating film on the side, the anode foil provided by the present invention is obtained by cutting the aluminum foil into a first anode foil of suitable size according to the requirements of the capacitor, and the first anode foil is immersed in a treatment liquid for pretreatment, wherein the treatment liquid includes a silicon compound, a solvent and an additive, and the additive includes one or more of boric acid, mannitol and sebacic acid. The silicon-containing film is repaired by the treatment liquid to fill the missing silicon film, thereby improving the withstand voltage of the anode foil, reducing the leakage current of the capacitor, reducing the gas production of the capacitor during aging, and extending the service life of the capacitor using the anode foil of the present invention.

[0047] In some embodiments of the present invention, the specification of the capacitor is 450V330uF 30*45, the withstand voltage of the first anode foil is 660VF, and the width is 35mm.

[0048] The present invention also provides an aluminum electrolytic capacitor, comprising a capacitor element and an electrolyte, wherein the capacitor element comprises a cathode foil, a diaphragm and the anode foil as described above, wherein the diaphragm is located between the cathode foil and the anode foil.

[0049] The present invention is further described below by way of examples. It should be understood that the present invention is not limited to the following examples, and methods are considered conventional methods unless otherwise specified. Materials can be obtained from public commercial sources unless otherwise specified.

[0050] Example 1

[0051] This embodiment is used to illustrate the electrolytic capacitor anode foil and the preparation method thereof disclosed in the present invention.

[0052] The preparation method of the aluminum electrolytic capacitor anode foil and the preparation of the treatment solution include the following steps:

[0053] Preparation of the treatment liquid: Based on the total weight of the treatment liquid being 100%, water, silicon dioxide and boric acid having the contents shown in Table 1 are uniformly mixed to obtain the treatment liquid;

[0054] Pretreatment of electrolytic capacitor anode foil: according to the required capacitor specifications (specifications are 450V330uF30*45), the whole roll of anode foil with a withstand voltage of 660V is cut into small rolls with a width of 35mm;

[0055] The anode foil is immersed in the treatment solution for 20 to 40 seconds and then dried to obtain the anode foil of the aluminum electrolytic capacitor of the present invention.

[0056] Embodiment 2-6

[0057] Examples 2-6 are used to illustrate the preparation method of the aluminum electrolytic capacitor anode foil and the preparation of the treatment solution disclosed in the present invention, including most of the operating steps in Example 1, and the difference is that:

[0058] The treatment liquid used the components and contents shown in Table 1.

[0059] Comparative Example 1

[0060] This comparative example 1 is used to compare and illustrate the aluminum electrolytic capacitor anode foil and the preparation method thereof disclosed in the present invention, and comprises the following steps:

[0061] Anode foil pretreatment of aluminum electrolytic capacitors: Cut the anode foil into the width required by the capacitor (35mm) without impregnation treatment.

[0062] Comparative Example 2

[0063] This comparative example 2 is used to compare and illustrate the preparation method of the aluminum electrolytic capacitor anode foil and the preparation of the treatment solution disclosed in the present invention, and includes most of the operating steps in Example 1, and the difference is that:

[0064] The treatment liquid used the components and contents shown in Table 1.

[0065] Table 1

[0066]

[0067] The content is based on the total weight of the treatment liquid as 100%.

[0068] Performance Evaluation

[0069] The electrical performance and silicon content of the anode foils prepared in the above-mentioned Examples 1-6 and Comparative Examples 1-2 were tested, and the test results are entered in Table 2.

[0070] Table 2

[0071]

[0072] It can be seen from the test results in Table 2 that, by comparing Examples 1-6 with Comparative Example 1-2, the withstand voltage performance of the anode foil soaked in the treatment solution is improved, the leakage current is significantly reduced, and the boost time is relatively shortened.

[0073] The anode foils prepared in the above-mentioned Examples 1-6 and Comparative Examples 1-2 were assembled into capacitors, and the electrical performance test and high temperature 115° C. load life test (450V 330uF, 30*45 capacitor) were performed on the capacitors. The test results are filled in Table 3.

[0074] Table 3

[0075]

[0076]

[0077] It can be seen from the test results in Table 3 that, compared with Examples 1-6 and Comparative Example 1-2, Example 1-6 has a smaller capacity attenuation of the capacitor, a smaller initial value and smaller change of the leakage current, a smaller △DF change rate, and a smaller change in the height △L of the capacitor (i.e., less gas production).

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an anode foil for an aluminum electrolytic capacitor, characterized in that: The following steps are involved: Cutting the foil according to the required size of the capacitor to obtain a first anode foil; immersing the first anode foil in a treatment solution and drying to obtain the anode foil; The treatment liquid includes a silicon compound, a solvent and an additive; The additive is selected from one or more of boric acid, mannitol and sebacic acid; The silicon content on the anode foil is 50-1000 ppm; Based on the total weight of the treatment liquid as 100%, the content of the silicon compound is 2% to 30%, the content of the solvent is 60% to 96%, and the content of the additive is 2% to 10%; The silicon compound is selected from one or more of silicon oxide, silicic acid and silicate; The solvent is selected from one or two of water and a mixed solvent consisting of water and an organic polar solvent; The organic polar solvent is selected from ethylene glycol and diethylene glycol.

2. The method for preparing an anode foil according to claim 1, characterized in that: Based on the total weight of the treatment liquid being 100%, the content of the silicon compound is 5% to 20%, the content of the solvent is 72% to 90%, and the content of the additive is 5% to 8%.

3. The method for preparing an anode foil according to claim 1, characterized in that: The silicon oxide is silicon dioxide, and the silicate includes sodium silicate and potassium silicate.

4. An aluminum electrolytic capacitor anode foil, characterized in that: An anode foil prepared by the method for preparing an anode foil for an aluminum electrolytic capacitor according to any one of claims 1 to 3.

5. An aluminum electrolytic capacitor, characterized in that: The invention comprises a capacitor element and an electrolyte, wherein the capacitor element comprises a cathode foil, a diaphragm and an anode foil prepared by the method for preparing an anode foil of an aluminum electrolytic capacitor according to any one of claims 1 to 3, and the diaphragm is located between the cathode foil and the anode foil.

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