An aluminum electrolytic capacitor electrode material and a method for manufacturing the same

Abstract

The application discloses an aluminum electrolytic capacitor electrode material, which comprises an aluminum foil base material and a sintered body layer, and the aluminum foil base material is an etched aluminum foil with a penetrating hole structure. The surface area of the electrode material is increased by the hole structure, so that the contact resistance is reduced, the heat generated during the use of the capacitor is reduced, and the loss of the capacitor is effectively reduced. The manufacturing method of the aluminum electrolytic capacitor electrode material comprises the following steps: first anodic oxidation treatment, removal of the oxide film, second anodic oxidation treatment, dispersion of mixed powder on the anodized aluminum foil base material, and sintering treatment to obtain the aluminum electrolytic capacitor electrode material. After the first anodic oxidation treatment, concaves are formed on the surface of the aluminum foil; then the oxide film is removed, and the concaves are uniformly distributed on the surface of the aluminum foil; and after the second anodic oxidation treatment, the penetrating hole structure is formed by extending into the aluminum foil along the concaves.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of anode foil formation, and particularly relates to an aluminum electrolytic capacitor electrode material and a manufacturing method thereof. BACKGROUND

[0002] Aluminum electrolytic capacitors are widely used in the information home appliance industry of computer, communication and consumer electronics integrated application. The electrode aluminum foil is a key material for manufacturing aluminum electrolytic capacitors, and the specific capacitance and dielectric performance thereof directly determine the volume and reliability of the aluminum electrolytic capacitor. Electrolytic surface corrosion and anode oxidation (commonly known as formation in industry) are key core technologies for manufacturing high specific capacitance electrode aluminum foil. Since aluminum is abundant in the earth's crust, its reserves and good ductility make it very widely used in industrial applications. In addition, aluminum has good electrical conductivity and thermal conductivity, and its melting point is 660℃ and boiling point is 2327℃. It is widely used in aerospace, automotive and construction industries, and also has applications in short-distance high-voltage power transmission. It also has applications in short arc machining, but due to its relatively low melting point, the electrode loss is relatively serious.

[0003] In the process of short arc milling machining, a gas-liquid mixture is used to reduce electrode loss. The specific operation is that the water vapor circulation system continuously sprays water vapor mixed medium between the electrodes during machining. However, in the use process of the electrode, the effect of this method for reducing electrode loss is not very reasonable. Therefore, there is an urgent need to develop an electrode material that can effectively reduce electrode loss and prolong the service life of the capacitor. SUMMARY

[0004] The purpose of the present application is to provide an aluminum electrolytic capacitor electrode material and a manufacturing method thereof, which can reduce the heat generation during the use of the capacitor and effectively reduce the loss of the capacitor.

[0005] In order to achieve the above-mentioned purpose of the application, the technical scheme of the present application comprises:

[0006] An aluminum electrolytic capacitor electrode material comprises an aluminum foil substrate and a sintered body layer, the aluminum foil substrate is a corroded aluminum foil with a penetrating pore structure, and the pore diameter of the corroded aluminum foil with the penetrating pore structure is 0.2-2.0 μm.

[0007] In the present application, the surface area of the electrode material is increased by the pore structure, thereby reducing the contact resistance, and further reducing the heat generation of the current and the heat generation during the use of the capacitor, and effectively reducing the loss of the capacitor.

[0008] In the aluminum electrolytic capacitor electrode material, the hole structure is distributed in a honeycomb shape on the etched aluminum foil, and the cross section of the hole structure is hexagonal, pentagonal or circular. Since the potential difference around the hole structure is relatively large, the electrochemical reaction occurs around the hole structure distributed in a honeycomb shape, avoiding the phenomenon that the electrochemical reaction occurs in a local area in the prior art, the area where the etching is concentrated is prone to breakage, thereby prolonging the service life of the capacitor.

[0009] In addition, the hexagonal, pentagonal and circular arrangement of the hole structure can improve the order of the hole structure, uniformly disperse the electrochemical reaction on the electrode material, avoid the phenomenon that the electrochemical reaction occurs in a local area in the prior art, and the area where the etching is concentrated is prone to breakage, thereby prolonging the service life of the capacitor.

[0010] In the aluminum electrolytic capacitor electrode material, the hole diameter of the etched aluminum foil with the penetrating hole structure is 0.8-1.5 μm.

[0011] In the aluminum electrolytic capacitor electrode material, the thickness of the etched aluminum foil is 10-100 μm, and the thickness ratio of the aluminum foil substrate to the sintered body layer is 1:(1-3).

[0012] In the aluminum electrolytic capacitor electrode material, the etched aluminum foil with the penetrating hole structure is obtained by the following process:

[0013] (a) placing the aluminum foil into an electrolyte with a concentration of 0.1-0.5 M, stirring for 8 hours at -5-6 C° and 30-160 V to obtain an anodized aluminum foil;

[0014] (b) removing the oxide film on the surface of the anodized aluminum foil obtained in step (1), and then placing it into an electrolyte with a concentration of 0.1-0.5 M, stirring for 8-12 hours at -5-6 C° and 30-160 V, and then using it.

[0015] In the aluminum electrolytic capacitor electrode material, the electrolyte includes oxalic acid and magnesium fluorosilicate, and the weight fraction of magnesium fluorosilicate is 1-5%. Using oxalic acid and magnesium fluorosilicate as the electrolyte can effectively improve the order of the hole structure arrangement and the uniformity of the hole diameter size, uniformly disperse the electrochemical reaction on the electrode material, avoid the phenomenon that the electrochemical reaction occurs in a local area in the prior art, and the area where the etching is concentrated is prone to breakage, thereby prolonging the service life of the capacitor.

[0016] The manufacturing method of the aluminum electrolytic capacitor electrode material includes the following steps:

[0017] (1) placing the aluminum foil into an electrolyte with a concentration of 0.1-0.5 M, stirring for 8 hours at -5-6 C° and 30-160 V to obtain an anodized aluminum foil;

[0018] (2) removing the oxide film on the surface of the anodized aluminum foil obtained in step (1) and then immersing the aluminum foil in an electrolyte having a concentration of 0.1-0.5 M at -5-6 °C and 30-160 V for 8-12 hours with stirring to obtain an anodized aluminum foil;

[0019] (3) weighing aluminum powder, valve metal oxide powder and aluminum-silicon alloy powder according to a mass ratio of 1: (5-200) for the valve metal oxide powder and aluminum powder and 1: (10-100) for the aluminum-silicon alloy powder, mixing the powders to obtain a mixed powder;

[0020] (4) dispersing the mixed powder on at least one side of the anodized aluminum foil substrate obtained in step (2) and compacting the aluminum foil to obtain a composite aluminum foil;

[0021] (5) sintering the composite aluminum foil to form a sintered layer on the surface of the aluminum foil substrate and thus obtaining an electrode material for aluminum electrolytic capacitors.

[0022] The manufacturing method of the present application forms indentations on the surface of the aluminum foil through a first anodization process and then forms a penetrating pore structure extending from the indentations into the aluminum foil through a second anodization process. In addition, the aluminum foil surface is formed with uniformly distributed indentations during the removal of the oxide film produced in the first anodization process, which facilitates the formation of an ordered pore structure after the second anodization process.

[0023] The manufacturing method of the aluminum electrolytic capacitor electrode material comprises the following steps:

[0024] (1) cleaning and polishing an aluminum foil substrate and then immersing the aluminum foil substrate in an electrolyte having a concentration of 0.1-0.5 M at -5-6 °C and 30-160 V and 600-1000 rpm for 8 hours with stirring to obtain an anodized aluminum foil substrate;

[0025] (2) immersing the anodized aluminum foil substrate obtained in step (1) in a film-removing solution for 5 min and then immersing the aluminum foil in an electrolyte having a concentration of 0.1-0.5 M at -5-6 °C and 30-160 V for 8-12 hours with stirring to obtain an anodized aluminum foil substrate;

[0026] (3) weighing aluminum powder, valve metal oxide powder and aluminum-silicon alloy powder according to a mass ratio of 1: (5-200) for the valve metal oxide powder and aluminum powder and 1: (10-100) for the aluminum-silicon alloy powder, mixing the powders to obtain a mixed powder;

[0027] (4) dispersing the mixed powder on at least one side of the anodized aluminum foil substrate obtained in step (2) to obtain a composite aluminum foil after compaction;

[0028] (5) subjecting the composite aluminum foil to thermalization treatment at 550-660°C for 1-60 min in an inert gas atmosphere;

[0029] (6) cooling the composite aluminum foil after thermalization treatment to 300°C and rolling to control the thickness and porosity of the sintered aluminum foil, forming a sintered layer on the surface thereof to obtain an aluminum electrolytic capacitor electrode material.

[0030] In the above method for preparing an aluminum electrolytic capacitor electrode material, in step (2), the annealing treatment is performed by cooling the aluminum foil after thermalization treatment to 300°C.

[0031] In the above method for preparing an aluminum electrolytic capacitor electrode material, the film removing solution is phosphoric acid and / or chromium trioxide, and the electrolyte solution comprises oxalic acid and magnesium fluosilicate, and the weight fraction of magnesium fluosilicate is 1-5%. The film removing solution used in the present application can remove the oxide film formed during the first anodization treatment, and at the same time, form uniformly distributed indentations on the surface of the aluminum foil, which is helpful to form ordered pore structures after the second anodization treatment.

[0032] Compared with the prior art, the present application has the following advantages:

[0033] (1) In the present application, the surface area of the electrode material is increased by the pore structure, thereby reducing the contact resistance, and further reducing the heat generation of the current and the heat generation during the use of the capacitor, and effectively reducing the loss of the capacitor.

[0034] (2) The manufacturing method of the present application forms indentations on the surface of the aluminum foil by the first anodization treatment, and then forms penetrating pore structures extending into the aluminum foil along the indentations after the second anodization treatment. In addition, during the removal of the oxide film formed during the first anodization treatment, the aluminum foil surface forms uniformly distributed indentations, which is helpful to form ordered pore structures after the second anodization treatment. DETAILED DESCRIPTION

[0035] The technical solutions of the present application will be further described in detail below in combination with specific examples.

[0036] Example 1

[0037] The aluminum electrolytic capacitor electrode material of the present example comprises an aluminum foil substrate and a sintered layer, and the aluminum foil substrate is a corroded aluminum foil with penetrating pore structures, the pore structures are distributed in a honeycomb shape on the corroded aluminum foil, the cross-sectional shape is hexagonal, and the pore diameter of the corroded aluminum foil with penetrating pore structures is 0.2 μm.

[0038] Specifically, the thickness of the etched aluminum foil is 10 μm, and the thickness ratio of the aluminum foil substrate to the sintered body layer is 1:1.

[0039] The manufacturing method of the aluminum electrolytic capacitor electrode material comprises the following steps:

[0040] (1) After cleaning and polishing treatment, the aluminum foil is placed in an electrolyte with a concentration of 0.1 M, stirred at -5 C°, 30 V, and 600 rpm for 8 hours to obtain an anodized aluminum foil;

[0041] (2) The anodized aluminum foil obtained in step (1) is immersed in phosphoric acid for 5 minutes, and then placed in an electrolyte with a concentration of 0.1 M, stirred at -5 C°, 30 V, and 600 rpm for 8 hours to obtain an anodized aluminum foil;

[0042] (3) The anodized aluminum foil obtained in step (2) is placed in an inert gas protective atmosphere and heat treated at 550 C° for 160 minutes. After cooling to 300 C°, the sintered aluminum foil is rolled to control the thickness and porosity, and a sintered body layer is formed on the surface of the anodized aluminum foil obtained in step (2) to obtain an aluminum electrolytic capacitor electrode material.

[0043] The electrolyte comprises oxalic acid and magnesium fluorosilicate, and the weight fraction of magnesium fluorosilicate is 1%.

[0044] Example 2

[0045] The aluminum electrolytic capacitor electrode material of the present embodiment comprises an aluminum foil substrate and a sintered body layer. The aluminum foil substrate is an etched aluminum foil with a penetrating hole structure, and the hole structure is distributed in a honeycomb shape on the etched aluminum foil. The shape of the hole structure cross section is a pentagon. The hole diameter of the etched aluminum foil with a penetrating hole structure is 2.0 μm.

[0046] Specifically, the thickness of the etched aluminum foil is 100 μm, and the thickness ratio of the aluminum foil substrate to the sintered body layer is 1:2.

[0047] The manufacturing method of the aluminum electrolytic capacitor electrode material comprises the following steps:

[0048] (1) After cleaning and polishing treatment, the aluminum foil is placed in an electrolyte with a concentration of 0.5 M, stirred at 6 C°, 160 V, and 1000 rpm for 8 hours to obtain an anodized aluminum foil;

[0049] (2) The anodized aluminum foil obtained in step (1) is immersed in chromium trioxide for 5 minutes, and then placed in an electrolyte with a concentration of 0.5 M, stirred at 6 C°, 160 V, and 600 rpm for 12 hours to obtain an anodized aluminum foil;

[0050] (3) the anodized aluminum foil obtained in step (2) is placed in an inert gas protective atmosphere and heat treated at 660°C for 160 min, the heat treated aluminum foil is cooled to 300°C, and then rolled to control the thickness and porosity of the sintered aluminum foil, thereby forming a sintered layer on the surface of the anodized aluminum foil obtained in step (2) to obtain the aluminum electrolytic capacitor electrode material.

[0051] The electrolyte comprises oxalic acid and magnesium fluosilicate, and the weight fraction of the magnesium fluosilicate is 5%.

[0052] Example 3

[0053] The aluminum electrolytic capacitor electrode material comprises an aluminum foil substrate and a sintered layer. The aluminum foil substrate is an etched aluminum foil with a penetrating porous structure, and the porous structure is distributed in a honeycomb shape on the etched aluminum foil. The shape of the cross section of the porous structure is circular. The pore size of the etched aluminum foil with the penetrating porous structure is 0.8 μm.

[0054] Specifically, the thickness of the etched aluminum foil is 20 μm, and the thickness ratio of the aluminum foil substrate to the sintered layer is 1:3.

[0055] The method for manufacturing the aluminum electrolytic capacitor electrode material comprises the following steps:

[0056] (1) after cleaning and polishing treatment, the aluminum foil is placed in an electrolyte with a concentration of 0.3 M, stirred at 0°C, 40 V and 800 rpm for 8 hours to obtain an anodized aluminum foil;

[0057] (2) the anodized aluminum foil obtained in step (1) is placed in phosphoric acid and soaked for 5 min, and then placed in an electrolyte with a concentration of 0.2 M, stirred at 0°C and 40 V for 10 hours to obtain an anodized aluminum foil;

[0058] (3) the anodized aluminum foil obtained in step (2) is placed in an inert gas protective atmosphere and heat treated at 600°C for 160 min, the heat treated aluminum foil is cooled to 300°C, and then rolled to control the thickness and porosity of the sintered aluminum foil, thereby forming a sintered layer on the surface of the anodized aluminum foil obtained in step (2) to obtain the aluminum electrolytic capacitor electrode material.

[0059] The electrolyte comprises oxalic acid and magnesium fluosilicate, and the weight fraction of the magnesium fluosilicate is 2%.

[0060] Example 4

[0061] The aluminum electrolytic capacitor electrode material of the embodiment comprises an aluminum foil substrate and a sintered body layer, the aluminum foil substrate is an etched aluminum foil with a penetrating hole structure, the hole structure is distributed in a honeycomb shape on the etched aluminum foil, and the shape of the hole structure section is a pentagon. The aperture of the etched aluminum foil with the penetrating hole structure is 1.5 μm.

[0062] Specifically, the thickness of the etched aluminum foil is 80 μm, and the thickness ratio of the aluminum foil substrate to the sintered body layer is 1:1.5.

[0063] The manufacturing method of the aluminum electrolytic capacitor electrode material comprises the following steps:

[0064] (1) After cleaning and polishing treatment of the aluminum foil, the aluminum foil is placed in an electrolyte with a concentration of 0.2 M, stirred at 5 C°, 50 V and 900 rpm for 8 hours to obtain an anodized aluminum foil;

[0065] (2) The anodized aluminum foil obtained in step (1) is put into chromium trioxide, soaked for 5 min, and then put into an electrolyte with a concentration of 0.2 M, stirred at 5 C° and 50 V for 11 hours to obtain an anodized aluminum foil;

[0066] (3) The anodized aluminum foil obtained in step (2) is placed in an inert gas protection atmosphere and heat treated at 650 C° for 160 min. After cooling the heat treated aluminum foil to 300 C°, the thickness and porosity of the sintered aluminum foil are controlled by rolling, a sintered body layer is formed on the surface of the anodized aluminum foil obtained in step (2), and the aluminum electrolytic capacitor electrode material is prepared.

[0067] The electrolyte comprises oxalic acid and magnesium fluosilicate, and the weight fraction of the magnesium fluosilicate is 4%.

[0068] Comparative Example 1

[0069] The difference between the comparative example 1 and the embodiment 4 is that the anodization treatment is not performed twice.

[0070] Comparative Example 2

[0071] The difference between the comparative example 2 and the embodiment 4 is that the anodization treatment is not performed twice.

[0072] The dielectric loss test is performed on the electrode materials prepared in the embodiments 1-4 and the comparative examples 1-2, and the test results are shown in the following table. The formation conditions are as follows: the electrolyte is 10% boric acid, the formation temperature is 90 C°, 0.05 A / cm 2 , and Vfe=361 V.

[0073] Table 1

[0074] No. tgδ No. tgδ Example 1 3.9 Example 4 3.6 Example 2 3.5 Comparative Example 1 5.5 Example 3 4.2 Comparative Example 2 5.1

[0075] As shown in the above table, the dielectric loss tgδ of the aluminum electrolytic capacitor electrode material prepared in Examples 1-4 is 3.5-4.2%; while the dielectric loss of the comparative example is larger, which can cause the dielectric temperature to rise and age, and even cause the thermal breakdown phenomenon to occur. It can be seen that the electrode material of Examples 1-4 increases the surface area of the electrode material through the porous structure, thereby reducing the contact resistance, and further reducing the heat generated during the use of the capacitor, effectively reducing the loss of the capacitor.

[0076] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Any simple modification, equivalent change and modification made according to the technical essence of the present application still belongs to the scope of the technical solution of the present application.

Claims

1. An aluminum electrolytic capacitor electrode material, characterized by, The aluminum foil substrate is an etched aluminum foil with a penetrating hole structure, and the hole diameter of the etched aluminum foil is 0.2-2.0 μm; The hole structure is distributed in a honeycomb shape on the etched aluminum foil, and the cross-sectional shape of the hole structure is hexagonal or pentagonal or circular; The etched aluminum foil with the penetrating hole structure is obtained by the following process: (a) placing the aluminum foil into an electrolyte with a concentration of 0.1-0.5 M, stirring for 8 hours at -5-6 C° and 30-160 V to obtain an anodized aluminum foil; (b) removing the oxide film on the surface of the anodized aluminum foil obtained in step (1), and then placing the aluminum foil into an electrolyte with a concentration of 0.1-0.5 M, stirring for 8-12 hours at -5-6 C° and 30-160 V; The electrolyte comprises oxalic acid and magnesium fluosilicate, and the weight fraction of the magnesium fluosilicate is 1-5%.

2. The aluminum electrolytic capacitor electrode material of claim 1, wherein The hole diameter of the etched aluminum foil with the penetrating hole structure is 0.8-1.5 μm.

3. The aluminum electrolytic capacitor electrode material of claim 1, wherein The thickness of the etched aluminum foil is 10-100 μm, and the thickness ratio of the aluminum foil substrate to the sintered body layer is 1:(1-3).

4. The method of making an aluminum electrolytic capacitor electrode material according to claim 1, wherein The process comprises the following steps: (1) placing the aluminum foil substrate into an electrolyte with a concentration of 0.1-0.5 M, stirring for 8 hours at -5-6 C° and 30-160 V to obtain an anodized aluminum foil substrate; (2) removing the oxide film on the surface of the anodized aluminum foil substrate obtained in step (1), and then placing the aluminum foil into an electrolyte with a concentration of 0.1-0.5 M, stirring for 8-12 hours at -5-6 C° and 30-160 V to obtain an anodized aluminum foil substrate; (3) weighing the aluminum powder, the valve metal oxide powder and the aluminum-silicon alloy powder according to the mass ratio of 1:(5-200) for the aluminum powder to the valve metal oxide powder and 1:(10-100) for the aluminum powder to the aluminum-silicon alloy powder, mixing to obtain a mixed powder; (4) dispersing the mixed powder on at least one side of the anodized aluminum foil substrate obtained in step (2), and compacting to obtain a composite aluminum foil; (5) performing sintering treatment on the composite aluminum foil to form a sintered body layer on the surface of the aluminum foil substrate, thereby obtaining an aluminum electrolytic capacitor electrode material.

5. The method of making an aluminum electrolytic capacitor electrode material according to claim 4, wherein The process comprises the following steps: (1) performing cleaning and polishing treatment on the aluminum foil substrate, and then placing the aluminum foil substrate into an electrolyte with a concentration of 0.1-0.5 M, stirring for 8 hours at -5-6 C°, 30-160 V and 600-1000 rpm to obtain an anodized aluminum foil substrate; (2) placing the anodized aluminum foil substrate obtained in step (1) into a film removal solution, soaking for 5 min, and then placing the aluminum foil substrate into an electrolyte with a concentration of 0.1-0.5 M, stirring for 8-12 hours at -5-6 C° and 30-160 V to obtain an anodized aluminum foil substrate; (3) aluminum powder, valve metal oxide powder and aluminum silicon alloy powder are weighed according to the mass ratio of valve metal oxide powder to aluminum powder being 1:(5-200) and the mass ratio of aluminum silicon alloy powder to aluminum powder being 1:(10-100), mixed to obtain mixed powder; (4) the mixed powder is dispersed on at least one side of the aluminum foil substrate subjected to anodic oxidation treatment obtained in step (2), and after compaction, a composite aluminum foil is obtained; (5) the composite aluminum foil is subjected to thermalization treatment at 550-660 ℃ for 1-60 min in an inert gas protection atmosphere; (6) the composite aluminum foil subjected to thermalization treatment is cooled to 300 ℃, rolled to control the thickness and porosity of the sintered aluminum foil, a sintered body layer is formed on the surface thereof, and an aluminum electrolytic capacitor electrode material is prepared.

6. The method of making an aluminum electrolytic capacitor electrode material according to claim 5, wherein The film removing solution is phosphoric acid and / or chromium trioxide, the electrolyte comprises oxalic acid and magnesium fluosilicate, and the weight fraction of magnesium fluosilicate is 1-5%.