An electrode structure material for low-voltage forming foil and its application

Abstract

The present invention discloses an electrode structure material for low-voltage forming foil and its application. The electrode structure material of the present invention includes an unetched aluminum core layer and an etching interval. The unetched aluminum core layer has a continuous through structure and is uniformly distributed perpendicular to the surface of the electrode structure material. The average thickness of the unetched aluminum core layer is 0.1-100 μm, and the distance between the unetched aluminum core layers is 20-1000 μm. The electrode structure material of the present invention has excellent bending performance and a high specific capacitance at the same time. When the specific capacitance is 84 μF / cm<supgt;2< / supgt;, its bending strength reaches 93 times. When the electrode structure material of the present invention is applied to an aluminum electrolytic capacitor, the unetched aluminum core layer significantly improves the effective contact area between the electrode structure material and the positive and negative leads, thereby reducing the contact resistance. Compared with the traditional electrode structure material, the contact resistance is reduced from 0.89 mΩ to 0.21 mΩ, reducing the risk of heat generation and breakdown of the electrode structure material.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum electrolytic capacitors, and more specifically, to an electrode structure material for low-voltage forming foil and its application. Background Art

[0002] In recent years, to meet the requirements of the integration of electronic products, miniaturization, high capacitance, and low cost have become the main development directions of aluminum electrolytic capacitors. Currently, etched foils are usually obtained by electrochemical etching technology to obtain sponge-like high-density etched micropores and thinner etched sandwich layers to improve their specific capacitance. However, while obtaining high specific capacitance, the bending strength of the forming foil is reduced.

[0003] To obtain a forming foil with both high specific capacitance and good bending performance, people have continuously developed new etched foil electrode structure materials. For example, the electrode structure material and the method for preparing the electrode structure material disclosed in Patent CN113035573A, and an electrode structure material for an aluminum electrolytic capacitor includes a base material and metal fibers with a certain angle on the surface of the base material. The anode foil made of this electrode structure material has a high specific capacitance, and its bending strength reaches up to 66 times at most. The prepared electrode structure material has poor bending performance at high specific capacitance; moreover, when applied to an aluminum electrolytic capacitor, the contact resistance between the positive and negative leads and the electrode structure material is large, which is extremely likely to cause problems such as heating and breakdown of the electrode structure material. Summary of the Invention

[0004] The object of the present invention is to overcome the structural limitations of the existing electrode structure materials, especially the electrode structure materials for preparing low-voltage forming foils, which have poor bending performance at high specific capacitance, and provide an electrode structure material for low-voltage forming foils. By regulating the unetched aluminum core layer with a specific structure and the etching interval, on the basis of maintaining a high specific capacitance of the electrode structure material, the bending performance of the electrode structure material is significantly improved.

[0005] Another object of the present invention is the application of the prepared electrode structure material for low-voltage forming foil in an aluminum electrolytic capacitor.

[0006] The above objects of the present invention are achieved by the following technical solutions:

[0007] An electrode structure material for low-voltage forming foil includes an unetched aluminum core layer and an etching interval; the unetched aluminum core layer has a continuous through structure and is uniformly distributed perpendicular to the surface of the electrode structure material. The average thickness of the unetched aluminum core layer is 0.1 - 100 μm; the distance between the unetched aluminum core layers is 20 - 1000 μm.

[0008] In the present invention, the uncorroded aluminum core layer with a through structure uniformly distributed perpendicular to the surface of the electrode structure material can effectively decompose the stress suffered during the bending process of the electrode structure material, improving its bending strength; while the sponge-like corrosion holes with small apertures can increase the specific volume of the electrode structure material, enabling the electrode structure material for low-voltage forming foil to have a high specific volume while maintaining good bending performance.

[0009] When the distance between the uncorroded aluminum core layers of the electrode structure material is fixed, the greater the average thickness of the uncorroded aluminum core layer, the smaller the proportion of the volume of the corrosion interval, which in turn leads to a decrease in its specific volume and an increase in the bending strength; when the average thickness of the uncorroded aluminum core layer of the electrode structure material is fixed, the greater the distance between the uncorroded aluminum core layers, the greater the proportion of the volume of the corrosion interval, which in turn leads to an increase in its specific volume and a decrease in the bending strength; if the average thickness of the uncorroded aluminum core layer is too large or the distance between the uncorroded aluminum core layers is too small, the proportion of the volume of the corrosion interval will be excessively reduced, resulting in too low a specific volume and making it difficult to meet the application requirements.

[0010] On the basis of ensuring a high specific volume, the electrode structure material of the present invention improves the structure of the uncorroded aluminum core layer by adjusting the uncorroded aluminum core layer that is horizontally distributed along the surface of the electrode structure material (as shown in Figure 4 ) to an uncorroded aluminum core layer that is vertically distributed along the surface of the electrode structure material and has a through structure (as shown in Figure 3 ). Compared with the existing electrode structure materials for low-voltage forming foil, when the specific volume is comparable, the bending strength of the electrode structure material is significantly improved.

[0011] Preferably, the average thickness of the uncorroded aluminum core layer is 1 - 100 μm, and the distance between the uncorroded aluminum core layers is 50 - 500 μm.

[0012] Preferably, the average thickness of the uncorroded aluminum core layer is 4.7 - 93 μm.

[0013] Preferably, the volume ratio of the uncorroded aluminum core layer to the corrosion interval is 1:(5 - 50).

[0014] Preferably, the volume ratio of the uncorroded aluminum core layer to the corrosion interval is 1:(5 - 10).

[0015] Preferably, the cross-sectional view of the uncorroded aluminum core layer along the horizontal direction of the electrode structure material is a pattern composed of several parallel or intersecting lines.

[0016] Preferably, the corrosion interval is composed of sponge-like corrosion holes, and the average aperture of the corrosion holes is 115 - 125 nm.

[0017] In the present invention, the average pore diameter of the corrosion holes in the corrosion zone needs to be controlled within a certain size range. Because if the average pore diameter of the corrosion holes is too large, the specific surface area of the corrosion zone will be too small, resulting in too low specific volume of the electrode structure material and making it difficult to meet the application requirements. At the same time, if the average pore diameter of the corrosion holes is too small, during the formation of low-voltage formed foils of the electrode structure material, the growth of the alumina film will block the corrosion holes, forming ineffective corrosion holes, which will also greatly reduce the specific volume of the electrode structure material. Therefore, the average pore diameter of the corrosion holes is generally 100 - 300 nm, and the more preferred range is 115 - 125 nm.

[0018] The application of an electrode structure material for low-voltage formed foils in the preparation of aluminum electrolytic capacitors is also within the protection scope of the present invention.

[0019] The present invention also protects an aluminum electrolytic capacitor prepared from raw materials including an electrode structure material for low-voltage formed foils.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] The present invention provides an electrode structure material for low-voltage formed foils. The electrode structure material includes an uncorroded aluminum core layer with a through structure and a corrosion zone. On the basis of ensuring a high specific volume, the uncorroded aluminum core layer with a through structure uniformly distributed perpendicular to the surface of the electrode structure material can effectively decompose the stress suffered during the bending process of the electrode structure material, thereby significantly improving the bending performance of the electrode structure material. When the specific volume is 84 μF / cm 2 its bending strength reaches 93 times.

[0022] When the electrode structure material for low-voltage formed foils in the present invention is applied to aluminum electrolytic capacitors, the uncorroded aluminum core layer with a through structure uniformly distributed perpendicular to the surface of the electrode structure material significantly improves the effective contact area between the electrode structure material and the positive and negative lead wires, thereby reducing the contact resistance. Compared with the traditional electrode structure material, the contact resistance is reduced from 0.89 mΩ to 0.21 mΩ, reducing the risk of heat generation and breakdown of the electrode structure material. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the electrode structure material for low-voltage formed foils in the present invention; 1. Corrosion zone; 2. Uncorroded aluminum core layer.

[0024] Figure 2 It is a cross-sectional schematic diagram of the electrode structure material for low-voltage formed foils in the present invention.

[0025] Figure 3 It is a cross-sectional scanning electron microscope image of the electrode structure material for low-voltage formed foils in Example 1.

[0026] Figure 4Cross-sectional scanning electron micrograph of the electrode structure material for low-voltage forming foil in Comparative Example 1. Detailed implementation manners

[0027] The present invention will be further described below in conjunction with the detailed implementation manners, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw material reagents used in the embodiments of the present invention are conventionally purchased raw material reagents.

[0028] Example 1

[0029] An electrode structure material for low-voltage forming foil (as Figure 1 shown) includes: an uncorroded aluminum core layer and a corrosion zone. The base material thickness of the electrode structure material is 95 μm;

[0030] The uncorroded aluminum core layer has a through structure and is uniformly distributed perpendicular to the surface of the electrode structure material (as Figure 2 , Figure 3 shown). Its average thickness is 19 μm, and the spacing is 500 μm;

[0031] The volume ratio of the uncorroded aluminum core layer to the corrosion zone is 1:25;

[0032] The corrosion zone is composed of sponge-like corrosion pores, and the average pore diameter of the corrosion pores is 115 nm.

[0033] Example 2

[0034] An electrode structure material for low-voltage forming foil includes: an uncorroded aluminum core layer and a corrosion zone. The base material thickness of the electrode structure material is 95 μm;

[0035] The uncorroded aluminum core layer has a through structure and is uniformly distributed perpendicular to the surface of the electrode structure material. Its average thickness is 46 μm, and the spacing is 500 μm;

[0036] The volume ratio of the uncorroded aluminum core layer to the corrosion zone is 1:10;

[0037] The corrosion zone is composed of sponge-like corrosion pores, and the average pore diameter of the corrosion pores is 117 nm.

[0038] Example 3

[0039] An electrode structure material for low-voltage forming foil includes: an uncorroded aluminum core layer and a corrosion zone. The thickness of the base material of the electrode structure material is 95 μm;

[0040] The uncorroded aluminum core layer has a through structure and is uniformly distributed perpendicular to the surface of the electrode structure material. Its average thickness is 93 μm, and the spacing is 500 μm;

[0041] The volume ratio of the uncorroded aluminum core layer to the corrosion zone is 1:5;

[0042] The corrosion area consists of sponge-like corrosion pores with an average pore diameter of 116 nm.

[0043] Example 4

[0044] An electrode structure material for low-voltage forming foil includes: an uncorroded aluminum core layer and a corrosion area; the substrate thickness of the electrode structure material is 95 μm;

[0045] The uncorroded aluminum core layer has a through structure and is uniformly distributed perpendicular to the surface of the electrode structure material, with a width of 19 μm and a spacing of 200 μm. The volume ratio of the uncorroded aluminum core layer to the corrosion area is 1:10;

[0046] The corrosion area consists of sponge-like corrosion pores with an average pore diameter of 121 nm.

[0047] Example 5

[0048] An electrode structure material for low-voltage forming foil includes: an uncorroded aluminum core layer and a corrosion area; the substrate thickness of the electrode structure material is 95 μm;

[0049] The uncorroded aluminum core layer has a through structure and is uniformly distributed perpendicular to the surface of the electrode structure material, with a width of 19 μm and a spacing of 1000 μm. The volume ratio of the uncorroded aluminum core layer to the corrosion area is 1:50;

[0050] The corrosion area consists of sponge-like corrosion pores with an average pore diameter of 117 nm.

[0051] Example 6

[0052] An electrode structure material for low-voltage forming foil includes: an uncorroded aluminum core layer and a corrosion area, and the substrate thickness of the electrode structure material is 95 μm;

[0053] The uncorroded aluminum core layer has a through structure and is uniformly distributed perpendicular to the surface of the electrode structure material, with an average thickness of 1.4 μm and a spacing of 20 μm;

[0054] The volume ratio of the uncorroded aluminum core layer to the corrosion area is 1:14;

[0055] The corrosion area consists of sponge-like corrosion pores with an average pore diameter of 118 nm.

[0056] Example 7

[0057] An electrode structure material for low-voltage forming foil includes: an uncorroded aluminum core layer and a corrosion area, and the substrate thickness of the electrode structure material is 95 μm;

[0058] The unetched aluminum core layer has a through structure and is evenly distributed perpendicular to the surface of the electrode structure material. Its average thickness is 4.7 μm, and the spacing is 50 μm;

[0059] The volume ratio of the unetched aluminum core layer to the corrosion zone is 1:10;

[0060] The corrosion zone consists of sponge-like corrosion pores, and the average pore diameter of the corrosion pores is 125 nm.

[0061] Example 8

[0062] An electrode structure material for low-voltage formation foil includes: an unetched aluminum core layer and a corrosion zone, and the substrate thickness of the electrode structure material is 120 μm;

[0063] The unetched aluminum core layer has a through structure and is evenly distributed perpendicular to the surface of the electrode structure material. Its average thickness is 0.4 μm, and the spacing is 20 μm;

[0064] The volume ratio of the unetched aluminum core layer to the corrosion zone is 1:50;

[0065] The corrosion zone consists of sponge-like corrosion pores, and the average pore diameter of the corrosion pores is 122 nm.

[0066] Comparative Example 1

[0067] An electrode structure material includes: an unetched aluminum core layer and a corrosion zone, and the thickness of the electrode structure material is 95 μm;

[0068] The unetched aluminum core layer is distributed horizontally along the surface of the electrode structure material (as Figure 4 shown), and its average thickness is 15 μm;

[0069] The volume ratio of the unetched aluminum core layer to the corrosion zone is 1:6;

[0070] The corrosion zone consists of sponge-like corrosion pores, and the average pore diameter of the corrosion pores is 123 nm.

[0071] Result Detection

[0072] (1) Bending strength and specific volume test

[0073] The bending strength is tested using a MIT-type bending machine from Toyo Seiki of Japan, with a chuck of R1.0.

[0074] The specific volume is tested using the 21V f small-sample formation method. The specific test method: The electrode structure materials obtained from Example 1 and Comparative Example 1 are formed using 21V fAfter the small samples are formed, 10 assembled capacitor products are produced. The product specifications are 16V 6800uF, and the product size is 16*25mm. Measure the contact resistance between the test electrode structure material and the lead and take its average value.

[0075] The test results show that the average contact resistance of the assembled capacitor after formation of the electrode structure material in Example 1 is 0.21mΩ, while the average contact resistance of the assembled capacitor after formation of the electrode structure material in Comparative Example 1 is 0.89mΩ. This is mainly because the uncorroded aluminum core layer in the electrode structure material of the present invention is distributed vertically on the surface of the electrode structure material (as shown in Figure 2 , Figure 3 ), and there are patterned uncorroded aluminum core layers on the surface of the formed foil after formation (as shown in Figure 1 ). During the winding process of the aluminum electrolytic capacitor, the contact area between the positive and negative leads and the uncorroded aluminum core layer is larger, resulting in a smaller contact resistance. This shows that the assembled capacitor using the electrode structure material provided by the present invention can effectively reduce the contact resistance of the capacitor, reduce the risk of heating and breakdown of the electrode material, and enable the capacitor to withstand a higher ripple current.

[0076] The specific test parameters and performance test results of the examples and comparative examples in the present invention are shown in Table 1: A is the thickness of the substrate of the electrode structure material; B is the distance between the uncorroded aluminum core layers; C is the average thickness of the uncorroded aluminum core layer; D is the average pore diameter of the corrosion holes; E is the volume ratio of the uncorroded aluminum core layer to the corrosion interval; F is the bending strength of the electrode structure material; G is the specific capacitance of the electrode structure material.

[0077] Table 1

[0078] Number A B C D E F G Example 1 95μm 500μm 19μm 115μm 1:25 87 times <![CDATA[90μF / cm 2 > Example 2 95μm 500μm 46μm 117μm 1:10 89 times <![CDATA[87μF / cm 2 > Example 3 95μm 500μm 93μm 116μm 1:5 93 times <![CDATA[84μF / cm 2 > Example 4 95μm 200μm 19μm 121μm 1:10 90 times <![CDATA[83μF / cm 2 > Example 5 95μm 1000μm 19μm 117μm 1:50 81 times <![CDATA[95μF / cm 2 > Example 6 95μm 20μm 1.4μm 118μm 1:14 86 times <![CDATA[93μF / cm 2 > Example 7 95μm 50μm 4.7μm 125μm 1:10 91 times <![CDATA[85μF / cm 2 > Example 8 120μm 20μm 0.4μm 122μm 1:50 85 times <![CDATA[93μF / cm 2 > Comparative Example 1 95μm / 15μm 123μm 1:6 81 times <![CDATA[88μF / cm 2 >

[0079] Specific capacitance and bending strength are a pair of opposing performance parameters. An increase in bending strength means a decrease in specific capacitance, and vice versa. On the basis of ensuring a comparable specific capacitance to that of the existing electrode structure material, the present invention changes the structure of the uncorroded aluminum core layer, adjusts the average thickness and spacing of the uncorroded aluminum core layer, so that its bending strength reaches 81-93 times, and it can be applied to formed foils with different bending strength and specific capacitance requirements.

[0080] It can be seen from Examples 1 to 3 that when the thickness of the electrode structure substrate and the distance between the uncorroded aluminum core layers are fixed, the bending strength of the electrode structure material increases with the increase of the average thickness of the uncorroded aluminum core layer, and the specific capacitance decreases with the increase of the average thickness of the uncorroded aluminum core layer.

[0081] It can be seen from Example 1, Example 4 and Example 5 that when the thickness of the electrode structure substrate and the average thickness of the uncorroded aluminum core layer are fixed, the bending strength of the electrode structure material decreases with the increase of the distance between the uncorroded aluminum core layers, and the specific capacitance increases with the increase of the distance between the uncorroded aluminum core layers.

[0082] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. An electrode structure material for low-voltage formation foil, characterized in that, the electrode structure material comprises: an unetched aluminum core layer and an etching interval; the unetched aluminum core layer has a continuous through structure and is uniformly distributed perpendicular to the surface of the electrode structure material, and the average thickness of the unetched aluminum core layer is 0.1 - 100 μm; the distance between the unetched aluminum core layers is 20 - 1000 μm; the volume ratio of the unetched aluminum core layer to the etching interval is 1:(5 - 50); the etching interval is composed of sponge-like etching holes, and the average pore diameter of the etching holes is 115 - 125 nm.

2. The electrode structure material for low-voltage formation foil according to claim 1, characterized in that, the average thickness of the unetched aluminum core layer is 1 - 100 μm, and the distance between the unetched aluminum core layers is 50 - 500 μm.

3. The electrode structure material for low-voltage formation foil according to claim 2, characterized in that, the average thickness of the unetched aluminum core layer is 4.7 - 93 μm.

4. The electrode structure material for low-voltage formation foil according to claim 1, characterized in that, the volume ratio of the unetched aluminum core layer to the etching interval is 1:(5 - 10).

5. The electrode structure material for low-voltage formation foil according to claim 1, characterized in that, the cross-sectional view of the unetched aluminum core layer along the horizontal direction of the electrode structure material is a pattern composed of a plurality of parallel or intersecting lines.

6. Application of the electrode structure material according to any one of claims 1 - 5 in the preparation of aluminum electrolytic capacitors.

7. An aluminum electrolytic capacitor, characterized in that, it is prepared from raw materials including the electrode structure material according to any one of claims 1 - 5.

Images