3D microporous foil and method for manufacturing the same, secondary battery

Abstract

The present application relates to a kind of 3D microporous foil and its preparation method, secondary battery, it is related to the field of microporous foil.The preparation method of the 3D microporous foil includes the following steps: forming roller is processed, and forming processing roller with the surface having protrusions is obtained;Foil is passed through the roll gap between the forming processing roller in roll-to-roll manner, and 3D protrusions are pressed out on the foil surface, while the protrusion top end penetrates to form microporous structure, and 3D microporous foil is obtained.The present application provides a kind of 3D microporous foil and its preparation method, the foil has 3D structure in addition to microporous, and has the advantages of large specific surface area, and electrode material is combined closely, and the efficiency of electron ion transmission is high, and manufacturing method is environmental protection, efficient, high consistency, suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention relates to the field of microporous foil materials, and more particularly to a 3D microporous foil material and its preparation method, and a secondary battery. Background Technology

[0002] In rechargeable batteries, foil, acting as a current collector, is one of the core components, and its performance directly affects the battery's performance. Traditional foils are mostly planar structures, which have problems such as small specific surface area, weak bonding with electrode active materials, and low electron-ion transport efficiency, thus limiting the improvement of battery energy density, charge-discharge rate, and cycle life.

[0003] To address these issues, researchers have attempted to improve performance by creating micropores on the surface of foils, such as using laser ablation or electrochemical etching to fabricate micropores on copper foils. However, existing micropore fabrication processes struggle to produce microporous foils with large micrometer-sized micropores, and the resulting microporous foils do not significantly improve the performance of secondary batteries. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a 3D microporous foil material, its preparation method, and a secondary battery.

[0005] In a first aspect, the present invention provides a method for preparing a 3D microporous foil, comprising the following steps: The forming roller is processed to obtain a forming processing roller with raised surfaces; The foil is passed through the gap between the forming rollers in a roll-to-roll manner, and 3D protrusions are pressed into the surface of the foil. At the same time, the top of the protrusions penetrates to form a microporous structure, thus obtaining a 3D microporous foil.

[0006] Furthermore, the parameters of the protrusions include: protrusion height of 30-100μm, protrusion diameter of 5-70μm, protrusion spacing of 50-200μm, and the protrusions arranged in a square array.

[0007] Furthermore, the processing of the forming roller includes at least one of laser etching and electrical discharge machining.

[0008] Furthermore, the working conditions parameters for the laser etching process include: power 5-25W, frequency 500-1000kHz, linear speed 100-200mm / s, and roll rotation speed 5r / min.

[0009] Furthermore, the protrusion includes at least one of cylindrical protrusion, conical protrusion, and regular square pyramidal protrusion.

[0010] Furthermore, the step of passing the foil through the gap between the forming rollers in a roll-to-roll manner to press 3D protrusions onto the foil surface, while the top of the protrusions penetrates to form a microporous structure, thereby obtaining a 3D microporous foil, includes the following processes: The forming rollers are installed in pairs on the forming machine, and the foil is passed through the gap between the two rollers in a roll-to-roll manner. Tension adjustment mechanisms are provided between the rollers and the winding and unwinding mechanisms. Adjust the position of the two rolls to completely offset the microscopic protrusions on the surface; apply tension to the foil between the rolls, with the unit tension controlled between 20-120 MPa; Apply pressure between the two rollers, with the total pressure controlled between 100-1500 kgf; The linkage winding and unwinding and roller drive device allows the foil to continuously pass through the forming roller. By adjusting the pressure and tension, 3D protrusions can be pressed onto the surface of the foil, and at the same time, the top of the protrusions penetrates to form a microporous structure, thus obtaining the 3D microporous foil.

[0011] Furthermore, the foil has a thickness of 4-25 μm, and the foil includes at least one of aluminum foil and copper foil.

[0012] Furthermore, before the foil enters the gap between the two forming rollers, the foil is preheated at a low temperature using an infrared preheating device, with the preheating temperature controlled at 80-150℃ (80-120℃ for aluminum foil and 100-150℃ for copper foil).

[0013] Secondly, the present invention provides a 3D microporous foil material, which is prepared by the method for preparing 3D microporous foil material described in the first aspect.

[0014] Thirdly, the present invention provides a secondary battery comprising the 3D microporous foil material described in the second aspect.

[0015] The technical solutions provided in the embodiments of the present invention have at least the following advantages compared with the prior art: This invention provides a 3D microporous foil material and its preparation method, as well as a secondary battery. The 3D microporous foil material, in addition to having micropores, also possesses a 3D structure, offering advantages such as large specific surface area, tight bonding with electrode materials, and high electron-ion transport efficiency. Furthermore, the manufacturing method is environmentally friendly, efficient, and highly consistent, making it suitable for large-scale industrial production. Specifically: (1) Significantly improved product performance: The 3D microporous foil material prepared by this invention forms a three-dimensional 3D protrusion + microporous composite structure. Compared with the existing planar microporous foil material, the specific surface area is increased by more than 50%, which greatly increases the contact area with the electrode active material, making the foil material and the electrode material more tightly bonded and effectively preventing the active material from falling off during charging and discharging. At the same time, the 3D structure constructs a smoother electron and ion transport channel, significantly improving the transport efficiency, and ultimately improving the energy density, charge and discharge rate and cycle life of the battery in all aspects.

[0016] (2) High processing efficiency, suitable for large-scale production: The roll-to-roll continuous roll forming process is adopted, and the processing speed is much higher than that of electrochemical etching and laser ablation processes. Moreover, the processing width is not limited and can be adjusted according to the needs of industrial production, which can realize the large-scale, continuous industrial production of 3D microporous foil.

[0017] (3) Good product consistency and stable quality: The laser etching precision of the forming roller is high, and the tension, pressure and other parameters of the rolling process can be precisely controlled. There are no complex chemical reactions or local deviations caused by laser ablation during the processing. The 3D microporous foil material produced has good uniformity in terms of protrusion structure, density, distribution and size of micropores, and the product quality is stable and controllable.

[0018] (4) Low production cost: The forming roller can be used repeatedly and for a long time after processing. The equipment operating cost and consumable cost of the roll forming process are much lower than those of the laser drilling equipment. Moreover, the process steps are simple and there is no need to equip a complex parameter monitoring system, which greatly reduces the labor cost and equipment maintenance cost in the production process. Compared with the existing technology, the overall production cost is reduced by 30%-40%.

[0019] Green and environmentally friendly, with no secondary pollution: The entire manufacturing process is physical roll forming, which does not require the use of acid and alkali solutions or electrolytes required for electrochemical etching, nor does it produce smoke and slag from laser ablation. There is no wastewater, waste gas, or solid waste discharge during the production process, which meets the requirements of green and environmentally friendly industrial production and does not require additional environmental protection equipment. Attached Figure Description

[0020] Figure 1 : A schematic diagram of a forming roller with raised surfaces in the preparation method of 3D microporous foil provided by the present invention.

[0021] Figure 2 : Schematic diagram of surface protrusions in the preparation method of microporous copper foil provided by the present invention.

[0022] Figure 3 : A schematic diagram of the working process of the microporous copper foil preparation method provided by the present invention.

[0023] Figure 4 : A partial enlarged view of the preparation method of microporous copper foil provided by the present invention. Detailed Implementation

[0024] The present invention will be specifically described below through embodiments. It should be noted that these embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of the present invention. Those skilled in the art can make some non-essential improvements and adjustments based on the above description of the present invention.

[0025] Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this invention can be purchased commercially or prepared using existing methods. Furthermore, unless otherwise specified or detailed, the steps and parameters involved can be performed according to existing processing techniques or using existing equipment; these will not be elaborated upon in detail in this invention document.

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] Example 1 This example provides a 3D microporous foil material, such as... Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, its preparation method includes the following steps: Using laser etching (specific parameters include: power 20W, frequency 800kHz, linear speed 150mm / s, roll rotation speed 5r / min), microscopic conical protrusions are engraved on a cylindrical steel roll, such as... Figure 1 As shown in the figure, and the specific parameters are shown in the table.

[0028] The forming rollers are installed in pairs on the forming machine. The foil is passed through the gap between the two rollers in a roll-to-roll manner. Tension adjustment mechanisms are provided between the rollers and the winding and unwinding mechanisms to adjust the position of the two rollers so that the microscopic protrusions on their surfaces are completely staggered. A certain tension is applied to the foil between the rollers. The structure of the forming machine is as follows. Figure 3 As shown in the figure, and the specific parameters are shown in Table 1.

[0029] A certain pressure is applied between the two rollers, and the specific parameters are shown in Table 1.

[0030] The linkage winding and unwinding and roller drive device makes the foil material continuously pass through the forming roller, pressing out 3D protrusions on the foil surface. At the same time, the top of the protrusion penetrates through (under low pressure, the foil surface only produces protrusion deformation. As the pressure continues to increase, the protrusion on the roller surface will pierce the foil, creating micropores at the top of the protrusion deformation of the foil), forming a microporous structure and obtaining 3D microporous foil material.

[0031] Table 1 Example 2 This example provides a 3D microporous foil and its preparation method. The difference from Example 1 is that the main condition parameters are adjusted as shown in Table 2.

[0032] Table 2 Comparative Example 1 The only difference between this example and Example 1 is that the height of the micro-protrusions on the forming roller is reduced to 25μm. When the height of the micro-protrusions on the forming roller is insufficient, protrusions can only be processed on the foil, and micropores cannot be formed at the top of the protrusions.

[0033] Comparative Example 2 The only difference between this example and Example 1 is that, keeping other parameters unchanged, the pressure between the two rollers is reduced from 370 kgf to 100 kgf, which can only process shallow protrusions on the foil surface and cannot form micropores on the top of the protrusions.

[0034] Test case This example tests the 3D microporous foil materials obtained in the above embodiments and comparative examples.

[0035] The testing methods include: 1) Surface roughness test: Use a roughness tester to test. 2) Number of holes per unit area: Use a microscope to detect light transmission, count the number of light-transmitting points, and calculate the number of holes per unit area.

[0036] 3) Capacity retention rate after 1000 cycles (%): After the test battery is manufactured, it is charged and discharged at a constant current of 0.5C for 1000 cycles. The remaining capacity / the capacity of the first cycle = the capacity retention rate.

[0037] 4) After the test battery is made, it is fully charged and then discharged at a constant current of 2C to test the discharge specific capacity.

[0038] The test results are shown in Tables 3 and 4.

[0039] Table 3 Test results of Example 1 and Comparative Examples 1-2 Table 4 Test results of Example 2 As shown in Table 3, the surface roughness of the 3D microporous aluminum foil produced by this method is significantly improved, and the surface has a large number of micropores.

[0040] As shown in Table 4, the 3D microporous copper foil made by this method has significantly improved cycle performance and fast charging performance in batteries compared to traditional smooth copper foil.

[0041] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for preparing a 3D microporous foil, characterized in that, Includes the following steps: The forming roller is processed to obtain a forming processing roller with raised surfaces; The foil is passed through the gap between the forming rollers in a roll-to-roll manner to press 3D protrusions on the surface of the foil. At the same time, the top of the protrusions penetrates to form a microporous structure, thus obtaining a 3D microporous foil.

2. The method for preparing 3D microporous foil according to claim 1, characterized in that, The parameters of the protrusions include: protrusion height 30-100μm, protrusion diameter 5-70μm, protrusion spacing 50-200μm, and the protrusions arranged in a square array.

3. The method for preparing 3D microporous foil according to claim 1, characterized in that, The forming roller can be processed by at least one of laser etching and electrical discharge machining.

4. The method for preparing 3D microporous foil according to claim 3, characterized in that, The working conditions for laser etching include: power 5-25W, frequency 500-1000kHz, linear speed 100-200mm / s, and roll rotation speed 5r / min.

5. The method for preparing 3D microporous foil according to claim 1, characterized in that, The protrusion includes at least one of cylindrical protrusion, conical protrusion, and regular square pyramidal protrusion.

6. The method for preparing 3D microporous foil according to claim 1, characterized in that, The steps of passing foil material through the gap between the forming rollers in a roll-to-roll manner to press 3D protrusions onto the foil surface, while simultaneously forming a microporous structure through the top of the protrusions, to obtain a 3D microporous foil material include the following processes: The forming rollers are installed in pairs on the forming machine, and the foil is passed through the gap between the two rollers in a roll-to-roll manner. Tension adjustment mechanisms are provided between the rollers and the winding and unwinding mechanisms. Adjust the position of the two rolls to completely offset the microscopic protrusions on the surface; apply tension to the foil between the rolls, with the unit tension controlled between 20-120 MPa; Apply pressure between the two rollers, with the total pressure controlled between 100-1500 kgf; The linkage winding and unwinding and roller drive device allows the foil to continuously pass through the forming roller. By adjusting the pressure and tension, 3D protrusions can be pressed onto the surface of the foil, and at the same time, the top of the protrusions penetrates to form a microporous structure, thus obtaining the 3D microporous foil.

7. The method for preparing 3D microporous foil according to claim 6, characterized in that, The foil has a thickness of 4-25 μm and includes at least one of aluminum foil and copper foil.

8. The method for preparing 3D microporous foil according to claim 6, characterized in that, Before the foil enters the gap between the two forming rollers, the foil is preheated at a low temperature using an infrared preheating device, with the preheating temperature controlled between 80-150℃.

9. A 3D microporous foil material, characterized in that, It is prepared by the method of any one of claims 1-8.

10. A secondary battery, characterized in that, Includes the 3D microporous foil material as described in claim 9.

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