Electrode foil with excellent longitudinal and transverse bending performance and preparation process thereof

Abstract

The invention belongs to the technical field of electrode foils, and particularly relates to an electrode foil with excellent longitudinal and transverse bending performance and a preparation process thereof. The electrode foil comprises an aluminum foil base material and a grain sintering layer formed on at least one surface of the aluminum foil base material, grains are formed on the surface of the grain sintering layer, and the grain orientation tends to be specific. According to the electrode foil with the excellent longitudinal and transverse bending performance, due to the fact that the lines tending to the specific orientation are formed on the surface of the coating, the lines can improve the transverse bending strength and the longitudinal bending strength, the difference of the transverse bending strength and the longitudinal bending strength of the surface of the electrode foil is reduced, and the transverse bending strength of the surface of the electrode foil is improved; the possibility of transverse cracking of the electrode foil in the formation and striping processes is further reduced; and meanwhile, the uniform thickness of the coating also avoids the problem of large specific volume dispersion difference after the electrode foil is formed, and the application scene of the sintered foil in the capacitor industry is widened.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrode foils, and particularly relates to an electrode foil with excellent longitudinal and transverse bending properties and a preparation process thereof. Background Art

[0002] Electrode foils are key raw materials for manufacturing capacitors. Their quality directly affects the service life of capacitors, and the specific capacitance affects the volume of capacitors. The traditional etching foil production process requires a large amount of environmentally polluting raw materials such as hydrochloric acid, sulfuric acid, and nitric acid, bringing great pressure to environmental protection treatment; at the same time, the upper limit of specific capacitance has reached a bottleneck and cannot be improved again. Therefore, in recent years, a method has been proposed to use a sintered body of porous aluminum powder made by sintering instead of an electrode foil for an aluminum anode whose surface area is increased by etching treatment, that is, a slurry is prepared from aluminum and aluminum alloy powders and coated on a metal substrate, and then sintered to form a sintered layer with multiple pores, so as to increase the specific surface area of the foil and improve the specific capacitance.

[0003] For example, Chinese Patent No. CN109036852A discloses a novel three-dimensional porous aluminum electrode foil and a preparation method thereof. The method for preparing the novel three-dimensional porous aluminum electrode foil includes: first, uniformly mixing aluminum-containing powder, aluminum fiber, and high-dielectric-constant oxide powder into a mixed powder; then uniformly dispersing the mixed powder on both sides of an aluminum foil substrate and compacting it to form a densely packed porous foil; then performing a thermal treatment on the porous foil and controlling the porosity to be 35% - 45% and the thickness to be 80μm - 200μm through extrusion treatment; finally, performing a forming and energizing treatment on the thermally treated porous aluminum electrode foil.

[0004] Another example is Chinese Patent No. CN102714098B, which discloses an electrode material for aluminum electrolytic capacitors and a preparation method thereof. The aluminum electrolytic capacitor electrode material provided by the invention, which is composed of a sintered body of at least one of aluminum and aluminum alloys and does not require etching treatment, can ensure a high electrostatic capacitance even when the particle size of the aluminum and aluminum alloy powders is small and the thickness of the sintered body is large. The aluminum electrolytic capacitor electrode material is composed of a sintered body of at least one of aluminum and aluminum alloy powders; (1) the average particle size D50 of the powder is 1 - 10μm; (2) the sintered body is composed of two or more sintered layers, and the average particle size D50 of the powder contained in adjacent sintered layers differs by more than 0.5μm.

[0005] The prior art has the following deficiencies: (1) The difference in longitudinal and transverse folding strengths increases, and the transverse folding strength is poor (R3.5 < 40 times), resulting in the problem of easy transverse cracking of the electrode foil during the forming and slitting processes; (2) The coating thickness uniformity is poor, and uneven thickness will cause a large specific capacitance dispersion after forming, greatly affecting the application of the sintered foil in the capacitor industry. Summary of the Invention

[0006] The object of the present invention is to provide an electrode foil with excellent longitudinal and transverse bending properties and a preparation process thereof. The electrode foil prepared by this electrode foil preparation technology has high transverse folding strength and uniform coating thickness.

[0007] To achieve the above object of the invention, the technical solution of the present invention is as follows:

[0008] An electrode foil with excellent longitudinal and transverse bending properties, which includes an aluminum foil substrate and a textured sintered layer formed on at least one side of the aluminum foil substrate. The surface of the textured sintered layer is formed with textures, and the texture orientation tends to be specific.

[0009] For the electrode foil with excellent longitudinal and transverse bending properties of the present invention, since textures with a specific orientation are formed on the surface of the coating, these textures can improve the transverse and longitudinal folding strengths. Thus, the difference in transverse and longitudinal folding strengths on the surface of the electrode foil is reduced, and the transverse folding strength on the surface of the electrode foil is also increased. Further, the possibility of transverse cracking during the slitting process in the formation and capacitor production processes of the electrode foil is reduced. At the same time, the uniform coating thickness also avoids the problem of large specific capacitance dispersion after the formation of the electrode foil, broadening the application scenarios of the sintered foil in the capacitor industry.

[0010] In the above-mentioned electrode foil with excellent longitudinal and transverse bending properties, the texture area accounts for more than 1% of the total surface area of the textured sintered layer. The width of the texture is between 1 - 50 μm, and the distance between adjacent two textures is between 10 - 1000 μm.

[0011] Since too small texture length will weaken the anti-bending effect, preferably, in the above-mentioned electrode foil with excellent longitudinal and transverse bending properties, the length of each texture in the extending direction of the textured sintered layer is 10 μm or more.

[0012] The present invention realizes that the texture orientation of the textured sintered layer tends to be specific by restricting the texture direction. That is, in the above-mentioned electrode foil with excellent longitudinal and transverse bending properties, the textures include longitudinal textures and transverse textures. The deviation angle between the extending direction of the longitudinal texture and the foil running direction is less than 45°, and the deviation angle between the transverse texture and the perpendicular direction of the foil running direction is less than 45°;

[0013] The area ratio of the longitudinal texture to the transverse texture is 1∶(0.1 - 10).

[0014] Preferably, in the above-mentioned electrode foil with excellent longitudinal and transverse bending properties, the area ratio of the longitudinal texture to the transverse texture is 1∶(0.33 - 3).

[0015] The present invention also provides a preparation process for an electrode foil with excellent longitudinal and transverse bending properties. The electrode foil preparation process includes the following steps:

[0016] S1 Preparation of fluid mixture: Mix 45 wt.% - 55 wt.% aluminum powder, 0.05 wt.% - 5 wt.% valve metal oxide powder, 0.5 wt.% - 7 wt.% binder, and 35 wt.% - 47 wt.% solvent evenly to obtain a fluid mixture;

[0017] S2 Preparation of composite aluminum foil: Evenly coat the fluid mixture on at least one side of an aluminum foil substrate, dry it, and then roll it using a textured roller to form a composite aluminum foil with at least one side having a textured coating;

[0018] S3 Sintering and forming: Horizontally place the composite aluminum foil in a vacuum atmosphere sintering furnace. First, convey a debinding atmosphere into the sintering furnace for debinding; then convey a sintering atmosphere into the sintering furnace for sintering. The sintering atmosphere circulates and convects in the sintering furnace and passes through the composite aluminum foil axially; sinter to form an electrode foil with excellent longitudinal and transverse bending properties.

[0019] Preferably, in step S1, the aluminum powder, valve metal oxide powder, binder, and solvent are mixed evenly in a mass ratio of 20:1:2:17. The average particle size of the aluminum powder is 0.5 - 30 μm, the valve metal oxide powder is titanium dioxide powder with an average particle size of 0.1 - 10 μm, the binder is polyvinylidene fluoride, and the solvent is N-methylpyrrolidone.

[0020] In step S3, specifically, horizontally place the foil roll in a vacuum atmosphere sintering furnace. First, convey a debinding atmosphere at 200 - 500 °C into the sintering furnace and debind for 1 - 10 h; then convey a sintering atmosphere at 550 - 650 °C into the sintering furnace. The sintering atmosphere circulates and convects in the sintering furnace and passes through the foil roll axially, and sinter for 4 - 12 h; among them, the debinding atmosphere is argon, and the sintering atmosphere is argon.

[0021] During the processes of conventional energization and anodic oxidation of this kind of electrode foil, abnormal phenomena such as foil breakage and cracking are not likely to occur. During the slitting process in subsequent capacitor production, abnormal phenomena such as cracking and tape breakage are also not likely to occur; greatly reducing the reprocessing difficulty for downstream customers.

[0022] In the above-mentioned preparation process of the electrode foil with excellent longitudinal and transverse bending properties, the textured roller in step S2 is a special-shaped roller, specifically as follows:

[0023] Use a special-shaped roller to roll the surface of the dried coating on the aluminum foil substrate to make fine textures appear on the coating, then use a conventional roller to roll to make the coating thickness uniform, and finally use a winder to wind it up.

[0024] Preferably, control the reduction amount according to the change in the thickness of the aluminum foil before and after passing through the roller, and it is required that the reduction amount of the aluminum foil thickness after passing through the roller ≤ 2 μm;

[0025] Preferably, according to different roll shapes, the speed range is 1 - 5 m / min.

[0026] In the present invention, through the roll pressing of the profiled roll, a pattern tending to a specific orientation is formed on the surface of the coating. The orientation of the pattern can be controlled by the shape of the profiled roll, and this kind of pattern can improve the transverse and longitudinal folding strengths. After the profiled roll pressing, the foil surface has undulations. The composite aluminum foil pattern is readjusted by the horizontal roll pressing, and at the same time, the coating thickness is made uniform, and the dispersion of the specific volume after formation is reduced.

[0027] In the above-mentioned preparation process of the electrode foil with excellent longitudinal and transverse bending properties, a plurality of strip-shaped or dot-shaped profiled parts are arranged on the surface of the profiled roll, and the plurality of profiled parts are arranged perpendicular to the axial direction of the profiled roll or circumferentially around the profiled roll.

[0028] The shape of the profiled roll can be adjusted according to specific requirements.

[0029] In the above-mentioned preparation process of the electrode foil with excellent longitudinal and transverse bending properties, the pattern roll in step S2 is a gravure roll, and the gravure roll has both heating and temperature control functions, specifically as follows:

[0030] A plurality of gravure rolls are used to perform hot stamping treatment on the surface of the coating after drying the aluminum foil substrate, and the pattern effect of the coating is controlled by setting the temperature of the gravure roll and the foil running tension.

[0031] Preferably, the pattern size adjustment is achieved through tension control, and the tension control range is 1 - 20 kg;

[0032] Preferably, the temperature control range of the gravure roll is 50 - 200 °C;

[0033] Preferably, according to different roll shapes, the speed range is 5 - 20 m / min.

[0034] Through the pattern and heating effect of the gravure roll, a pattern tending to a specific orientation is formed on the surface of the coating. This kind of pattern can improve the transverse and longitudinal folding strengths, and the orientation of the pattern can be controlled by the pattern of the gravure roll.

[0035] In the above-mentioned preparation process of the electrode foil with excellent longitudinal and transverse bending properties, a plurality of pattern parts forming a pattern are arranged on the surface of the gravure roll. The pattern parts are dot-shaped pattern parts uniformly distributed on the surface of the gravure roll; or, the pattern parts are long filament-shaped pattern parts having the same axial length as the gravure roll and radially surrounding the surface of the gravure roll; or, the pattern parts are a plurality of short filament-shaped pattern parts circumferentially surrounding the surface of the gravure roll.

[0036] When threading the gravure roll, two gravure rolls are arranged successively along the advancing direction of the foil roll, and a height difference is formed between the two gravure rolls.

[0037] In the above-mentioned preparation process of the electrode foil with excellent longitudinal and transverse bending properties, in step S2, a fluid mixture is symmetrically coated on both sides of an aluminum foil substrate with a thickness of 10 - 50 μm by a coater, and the coating thickness on each side is 55 - 65 μm. After drying, a rolling treatment is carried out to make the total thickness of the obtained composite aluminum foil 120 - 180 μm.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] (1) For the electrode foil with excellent longitudinal and transverse bending properties of the present invention, since a texture tending to a specific orientation is formed on the coating surface, this kind of texture can improve the transverse and longitudinal folding strengths, thereby reducing the difference in the transverse and longitudinal folding strengths on the surface of the electrode foil and also enhancing the transverse folding strength on the surface of the electrode foil, further reducing the possibility of transverse cracking easily occurring during the formation and slitting processes of the electrode foil; at the same time, the uniform coating thickness also avoids the problem of large specific volume dispersion after the electrode foil is formed, broadening the application scenarios of the sintered foil in the capacitor industry.

[0040] (2) By rolling with a profiled roller in the present invention, a texture tending to a specific orientation is formed on the coating surface, and the orientation of the texture can be controlled by the shape of the profiled roller. This kind of texture can improve the transverse and longitudinal folding strengths; after the profiled roller rolling, the foil surface has undulations, and the shape of the composite aluminum foil is readjusted by horizontal rolling, while making the coating thickness uniform and reducing the dispersion of the specific volume after formation. Description of the Drawings

[0041] Figure 1 It is a schematic structural diagram of one embodiment of the profiled roller in the electrode foil preparation process of the present invention;

[0042] Figure 2 It is a schematic structural diagram of another embodiment of the profiled roller in the electrode foil preparation process of the present invention;

[0043] Figure 3 It is a schematic structural diagram of another embodiment of the profiled roller in the electrode foil preparation process of the present invention;

[0044] Figure 4 It is a schematic diagram of the foil running process of the treatment process combining profiled roller rolling and horizontal rolling in the electrode foil preparation process of the present invention;

[0045] Figure 5 It is a schematic structural diagram of one embodiment of the engraved roller in the electrode foil preparation process of the present invention;

[0046] Figure 6 It is a schematic structural diagram of another embodiment of the engraved roller in the electrode foil preparation process of the present invention;

[0047] Figure 7 It is a schematic structural diagram of another embodiment of the engraved roller in the electrode foil preparation process of the present invention;

[0048] Figure 8 Schematic diagram of threading the anilox roll in the electrode foil preparation process of the present invention;

[0049] Figure 9 Schematic diagram of the longitudinal texture of the electrode foil prepared in Example 1 or 4;

[0050] Figure 10 Schematic diagram of the transverse texture of the electrode foil prepared in Example 2 or 5;

[0051] Figure 11 Schematic diagram of the texture of the electrode foil prepared in Example 3 or 6;

[0052] Figure 12 Schematic diagram of the texture of the electrode foil prepared in Comparative Example 1;

[0053] Figure 13 SEM image of the texture of the electrode foil prepared in Example 1 or 4. Detailed Description of the Invention

[0054] The following are specific embodiments to further elaborate on the technical solutions of the present invention in detail.

[0055] Example 1

[0056] This example provides an electrode foil preparation process with excellent longitudinal and transverse bending properties, including the following steps:

[0057] S1 Prepare a fluid mixture: Mix 50 wt.% aluminum powder, 2.5 wt.% valve metal oxide powder, 5 wt.% binder, and 42.5 wt.% solvent evenly according to a mass ratio of 20:1:2:17 to obtain a fluid mixture; the average particle size of the aluminum powder is 3 μm, the valve metal oxide powder is titanium dioxide powder with an average particle size of 100 nm, the binder is polyvinylidene fluoride, and the solvent is N-methylpyrrolidone;

[0058] S2 Prepare a composite aluminum foil: Uniformly coat the fluid mixture on at least one side of the aluminum foil substrate, and after drying, perform a rolling treatment using an anilox roll to form a composite aluminum foil with at least one side having a textured coating;

[0059] Specifically, use a coater to symmetrically coat the fluid mixture on both sides of an aluminum foil substrate with a thickness of 20 μm, and the single-sided coating thickness is 55 - 65 μm;

[0060] After drying, perform the rolling treatment as shown in Figure 4 : Use a special-shaped roll as shown in Figure 1 to perform a rolling treatment on the composite aluminum foil to make fine textures appear on the coating, then use a conventional roll for rolling to make the coating thickness uniform, and finally use a winder to wind up so that the total thickness of the obtained composite aluminum foil reaches 130 μm;

[0061] S3 Sintering and forming: Horizontally place the foil roll in a vacuum atmosphere sintering furnace. First, convey a debinding atmosphere at 450°C into the sintering furnace and carry out debinding for 5 hours. Then, convey a sintering atmosphere at 620°C into the sintering furnace. The sintering atmosphere circulates and convects in the sintering furnace and passes through the foil roll axially, and sintering is carried out for 10 hours. The debinding atmosphere is argon, and the sintering atmosphere is argon;

[0062] S4 Perform energization and anodic oxidation treatment on the sintered and formed composite aluminum foil to obtain an electrode foil with excellent longitudinal and transverse bending properties.

[0063] Example 2

[0064] This example provides a preparation process for an electrode foil with excellent longitudinal and transverse bending properties, which is basically the same as Example 1. The difference lies in that: in step S2, the composite aluminum foil is roll-pressed using the special-shaped roll as shown in Figure 2 the figure.

[0065] Example 3

[0066] This example provides a preparation process for an electrode foil with excellent longitudinal and transverse bending properties, which is basically the same as Example 1. The difference lies in that: in step S2, the composite aluminum foil is roll-pressed using the special-shaped roll as shown in Figure 3 the figure.

[0067] Example 4

[0068] This example provides a preparation process for an electrode foil with excellent longitudinal and transverse bending properties, which is basically the same as Example 1. The difference lies in that:

[0069] in step S2, after drying, the roll-pressing treatment is carried out as shown in Figure 8 the figure: Use the engraved roll as shown in Figure 5 to carry out pressing and ironing treatment on the composite aluminum foil. This roll has both heating and temperature control functions; the coating texture effect can be controlled by setting the temperature of the engraved roll and the foil running tension.

[0070] Example 5

[0071] This example provides a preparation process for an electrode foil with excellent longitudinal and transverse bending properties, which is basically the same as Example 1. The difference lies in that:

[0072] in step S2, after drying, the roll-pressing treatment is carried out as shown in Figure 8 the figure: Use the engraved roll as shown in Figure 6 to carry out pressing and ironing treatment on the composite aluminum foil.

[0073] Example 6

[0074] This embodiment provides a preparation process for electrode foils with excellent longitudinal and transverse bending properties, which is basically the same as that of Embodiment 1, except that:

[0075] In step S2, after drying, Figure 8 the following rolling treatment is carried out: using Figure 7 the engraved roller shown as follows to press and iron the composite aluminum foil.

[0076] Comparative Example 1

[0077] The preparation process for electrode foils provided in this comparative example is basically the same as that of Embodiment 1, except that:

[0078] S2 Prepare the composite aluminum foil: uniformly coat the fluid mixture on at least one side of the aluminum foil substrate to form a composite aluminum foil with at least one coated side;

[0079] Specifically, use a coater to symmetrically coat the fluid mixture on both sides of an aluminum foil substrate with a thickness of 20 μm, and the single-sided coating thickness is 55 - 65 μm; after drying, use a conventional roller for rolling, and finally wind it with a winder so that the total thickness of the obtained composite aluminum foil reaches 130 μm.

[0080] This treatment method cannot form a textured sintered layer.

[0081] Test Example

[0082] Perform performance tests on the electrode foils prepared in Embodiments 1 - 6 and Comparative Example 1. The test method refers to the group standard T / CECA 22 - 2017 Electrode Foils for Aluminum Electrolytic Capacitors of the China Electronic Components Industry Association. The test results are as follows in the table:

[0083] Table 1 Performance Test Results of Electrode Foils Prepared in Embodiments 1 - 6 and Comparative Example 1

[0084]

[0085] As can be seen from Table 1, the transverse bending strength of the electrode foils in Embodiments 1 - 6 is several times that of Comparative Example 1, greatly improving the transverse folding strength of the electrode foils. Among them, in Embodiments 1 - 3, due to the rolling treatment, the coating uniformity is higher, so the scatter value is reduced; the scatter value in Embodiments 4 - 6 is not reduced. The difference in transverse and longitudinal folding strength between Embodiment 3 and Embodiment 6 is the smallest. The ratio of the longitudinal texture to the transverse texture in Embodiment 1 and Embodiment 4 is close to 3:1, and the longitudinal folding performance is worse than the transverse folding performance; the ratio of the longitudinal texture to the transverse texture in Embodiment 2 and Embodiment 5 is close to 1:3, and the longitudinal folding performance is better than the transverse folding performance; in Embodiment 3 and Embodiment 6, the ratio of the longitudinal texture to the transverse texture is close to 1:1, and the longitudinal folding performance is close to the transverse folding performance.

[0086] In addition, from the table, the advantages and disadvantages of the special-shaped rolling scheme are as follows:

[0087] Advantages: (1) The formed texture is more obvious, and the transverse and longitudinal folding performance is better; (2) The coating is uniform, and the specific volume dispersion is small. Disadvantages: (1) The coating is easily damaged during the rolling process, and the reduction amount is difficult to control; (2) The production speed is low and the efficiency is not high.

[0088] The advantages and disadvantages of the anilox roll solution are as follows:

[0089] Advantages: (1) It is not easy to damage the coating; (2) The production efficiency is relatively high. Disadvantages: (1) It is relatively difficult to form a texture; (2) The coating is not uniform, and the specific volume dispersion is large.

[0090] The test results of Example 3 are the best, indicating that the special-shaped roll used in Example 3, as Figure 3 shown, is more conducive to forming a texture with a specific orientation on the coating surface.

[0091] As Figure 9 , Figure 10 and Figure 12 shown, the texture of the electrode foil prepared in Example 3 is shown; Figure 11 The texture of the electrode foil prepared in Comparative Example 1 is shown; By comparison, it can be seen that the preparation process provided by the present invention can prepare an electrode foil with a specific orientation texture, that is, an electrode foil with excellent longitudinal and transverse bending performance.

[0092] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. An electrode foil with excellent longitudinal and transverse bending properties, characterized in that: It includes an aluminum foil substrate and a textured sintered layer formed on at least one side of the aluminum foil substrate. The surface of the textured sintered layer has textures, and the texture orientation tends to be specific.

2. The electrode foil with excellent longitudinal and transverse bending properties as described in claim 1, characterized in that: The texture area accounts for more than 1% of the total surface area of the textured sintered layer. The width of the texture is between 1 - 50 μm, and the distance between two adjacent textures is between 10 - 1000 μm.

3. The electrode foil with excellent longitudinal and transverse bending properties as described in claim 1, characterized in that: The length of each texture of the textured sintered layer in the extending direction is 10 μm or more.

4. The electrode foil with excellent longitudinal and transverse bending properties as described in claim 1, characterized in that: The textures include longitudinal textures and transverse textures. The deviation angle between the extending direction of the longitudinal texture and the foil running direction is less than 45°, and the deviation angle between the transverse texture and the perpendicular direction of the foil running direction is less than 45°; The area ratio of the longitudinal texture to the transverse texture is 1∶(0.1 - 10).

5. A preparation process for an electrode foil with excellent longitudinal and transverse bending properties, characterized in that: It includes the following steps: S1 Prepare a fluid mixture: Mix 45wt.% - 55wt.% aluminum powder, 0.05wt.% - 5wt.% valve metal oxide powder, 0.5wt.% - 7wt.% binder, and 35wt.% - 47wt.% solvent evenly to obtain a fluid mixture; S2 Prepare a composite aluminum foil: Evenly coat the fluid mixture on at least one side of the aluminum foil substrate, dry it, and then perform rolling treatment with a textured roller to form a composite aluminum foil with at least one side having a textured coating; S3 Sintering and forming: Horizontally place the composite aluminum foil in a vacuum atmosphere sintering furnace. First, convey a degreasing atmosphere into the sintering furnace for degreasing; then convey a sintering atmosphere into the sintering furnace for sintering. The sintering atmosphere circulates and convects in the sintering furnace and passes through the composite aluminum foil axially, and sintering forms an electrode foil with excellent longitudinal and transverse bending properties.

6. The preparation process of the electrode foil with excellent longitudinal and transverse bending properties as described in claim 5, characterized in that: The textured roller in step S2 is a special-shaped roller, specifically as follows: Use a special-shaped roller to roll the surface of the coating on the aluminum foil substrate after drying, so that fine textures appear on the coating, then use a conventional roller to roll to make the coating thickness uniform, and finally use a winder to wind.

7. The preparation process of the electrode foil with excellent longitudinal and transverse bending properties according to claim 6, characterized in that: A plurality of strip-shaped or dot-shaped special-shaped parts are arranged on the surface of the special-shaped roller, and the plurality of special-shaped parts are arranged perpendicular to the axial direction of the special-shaped roller or circumferentially around the special-shaped roller.

8. The preparation process of the electrode foil with excellent longitudinal and transverse bending properties as described in claim 7, characterized in that: The textured roller in step S2 is a gravure roller, and the gravure roller has both heating and temperature control functions, specifically as follows: Use several gravure rollers to perform hot stamping treatment on the surface of the coating on the aluminum foil substrate after drying, and control the coating texture effect by setting the temperature of the gravure roller and the foil running tension.

9. The preparation process of the electrode foil with excellent longitudinal and transverse bending properties as claimed in claim 8, characterized in that: The surface of the gravure roller is provided with a plurality of texture parts forming a pattern. The texture parts are dot-shaped texture parts evenly distributed on the surface of the gravure roller; or, the texture parts are long filamentous texture parts having the same length as the axial length of the gravure roller and radially surrounding the surface of the gravure roller; or, the texture parts are a plurality of short filamentous texture parts circumferentially surrounding the surface of the gravure roller.

10. The preparation process of the electrode foil with excellent longitudinal and transverse bending properties as described in claim 9, characterized in that: In step S2, use a coater to symmetrically coat the fluid mixture on both sides of an aluminum foil substrate with a thickness of 10 - 50 μm. The single-sided coating thickness is 55 - 65 μm. After drying, perform rolling treatment to make the total thickness of the obtained composite aluminum foil 120 - 180 μm.

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