Aluminum foil for lithium battery and preparation method of aluminum foil

Abstract

The invention relates to the technical field of battery aluminum foils, in particular to an aluminum foil for a lithium battery, which comprises the following components in percentage by mass: 0.06-0.09% of Si; 0.10% to 0.15% of Fe; 0.04% to 0.05% of Cu; 0.01% of Mn; 0.01% of Mg; 0.01% of Cr; 0.01% of Zn; 0.02% to 0.03% of Ti; aI is greater than or equal to 99.60%, and the balance is impurities. Meanwhile, aluminum foil length detection is carried out by utilizing the conductivity characteristic of the aluminum foil after the single aluminum foil finished product is stripped, then detection data are substituted into a formula to calculate whether the aluminum foil plate shape is qualified or not, and the detection is stable, reliable and high in precision. The sponge is used for being in contact with the aluminum foil, and the aluminum foil is blown flat or adsorbed by positive and negative pressure, so that the aluminum foil can be prevented from being damaged during detection, the aluminum foil is detected in a flat posture, and the accuracy of a detection result is ensured. When aluminum foil finished products are detected, the detection main body moves along with the aluminum foil conveyed on the assembly line, the assembly line does not need to be stopped during detection, and efficiency is prevented from being affected by line stopping.

Description

Technical Field

[0001] This invention relates to the field of battery aluminum foil technology, specifically to an aluminum foil for lithium batteries and its preparation method. Background Technology

[0002] With the improvement of people's living standards and the enhancement of environmental awareness, there is a huge social demand for clean and environmentally friendly energy transportation tools. Electric vehicles have become a major means of transportation in people's lives. The power battery for electric vehicles is a lithium battery, and the positive electrode current collector of the lithium battery is aluminum foil. This aluminum foil requires high dimensional accuracy. The aluminum foil surface must be uniform in color, clean, free of corrosion marks, color difference, scratches, horizontal lines, and other defects, and the plate shape must be flat. The alloy generally used to manufacture aluminum foil for pure electric vehicle batteries is alloy 1100, with an aluminum content of ≥99.00%. The performance of the aluminum foil is generally average, which results in average performance of the lithium battery. Summary of the Invention

[0003] To achieve the above objectives, the present invention specifically adopts the following technical solution: An aluminum foil for lithium batteries comprises the following components by mass percentage: Si: 0.06%-0.09%; Fe: 0.10%-0.15%; Cu: 0.04%-0.05%; Mn: 0.01%; Mg: 0.01%; Cr: 0.01%; Zn: 0.01%; Ti: 0.02%-0.03%; Al ≥ 99.60%, with the balance being impurities.

[0004] The above-mentioned method for preparing aluminum foil for lithium batteries includes the following steps: S1: Composition blending and casting. Pure aluminum, Fe, Si and Cu intermediate alloy materials are loaded into a melting furnace for melting and slag removal. After melting, it is transferred to refining. During refining, samples are taken to analyze the composition. After the composition is qualified, it is cast into aluminum ingots.

[0005] S2: Ingot rolling. The aluminum ingot obtained in the previous step is heated and then hot rough rolling is performed. After hot rough rolling, finish rolling is performed to roll the aluminum alloy strip to a thickness of 6mm-7mm. Then, four passes of cold rolling are performed to process the finished thickness to 80%-92%. Then, intermediate annealing is performed using an air cushion continuous annealing furnace. After annealing and cooling, two passes of cold rolling are performed.

[0006] S3: Foil rolling, which involves four passes of foil rolling. First, three passes of foil rolling are performed, followed by 24 hours of cooling, and then the remaining foil rolling is performed until the desired thickness is achieved.

[0007] S4: Inspection and Packaging. After the aluminum foil is cut from the rolling mill, it is transferred to the slitting machine for cutting into rolls of the required width. The aluminum foil on the rolls is then divided into individual aluminum foils. The length of the individual aluminum foils is checked using an online detection device. Once the inspection is qualified, they can be packaged.

[0008] Furthermore, the online testing device includes a square housing with pre-set openings at both the front and rear ends. A movable plate is installed inside the openings, and multiple test copper plates are installed on the bottom of the side of the movable plate facing the middle of the housing. Wires are connected between the front and rear test copper plates, and a switch, a load, and a power supply are connected in series on the wires. Wires are also connected between adjacent test copper plates at the front and rear ends of the housing, and a switch, a load, and a power supply are connected in series on the wires. The top of the movable plate extends above the housing. Supports are installed at both the front and rear of the top of the housing. An electric cylinder is installed on the top of the support. The output end of the electric cylinder is installed at the top center of the movable plate. There is a pre-set mounting groove on the housing below the support. A lifting cylinder is installed in the mounting groove. The support is installed at the output end of the lifting cylinder.

[0009] Furthermore, horizontal support rods are installed on both ends of the movable plate facing the shell. Square limiting blocks are movably sleeved on the horizontal support rods. A limiting frame is installed on the top of the shell at a position perpendicular to the horizontal support rods. A limiting groove is preset in the limiting frame, and the limiting blocks are located in the limiting groove and are movably sleeved up and down.

[0010] Furthermore, a partition is fixed in the middle of the housing, a pad frame is fixed at the bottom of the partition, a sponge is installed inside the housing at the bottom of the pad frame, a sealing film is fixed on the side of the sponge, and an air inlet pipe and an air extraction pipe are installed in the middle of the top of the housing. One end of the air inlet pipe and the air extraction pipe both pass through the partition and extend between the partition and the sponge. The other end of the air inlet pipe and the air extraction pipe are respectively connected to the input end of the gas booster pump and the vacuum pump.

[0011] Furthermore, a threaded sleeve and a sliding sleeve are respectively installed at the front and rear ends of the top of the housing. A lead screw and a sliding rod pass through the threaded sleeve and the sliding sleeve respectively. The lead screw is threadedly connected to the threaded sleeve, and the sliding rod is movably sleeved with the sliding sleeve. A support platform is installed below both ends of the lead screw and the sliding rod. A bearing seat is installed on the top of the support platform. Both ends of the lead screw and the sliding rod are sleeved with the bearing seat. A motor is installed on the support platform at one end of the lead screw, and the output end of the motor is plugged into the lead screw.

[0012] Furthermore, a base is installed directly below the support platform, and lifting columns are fixed at both ends of the top of the base. The top of the lifting columns is installed between the support platform and the top of the support platform. An electric cylinder is installed in the middle of the top of the base. The output end of the electric cylinder is installed in the base. A binocular camera is installed in the middle of the front end of the housing.

[0013] Furthermore, a support frame is installed below the base, and a linear module is installed on the top of the support frame. A slide table that slides along the linear module is threaded onto the linear module, and the base is installed on the slide table.

[0014] Beneficial effects: 1. This invention improves conductivity and tensile strength, and gives it good corrosion resistance, as well as good mechanical properties and stability, by controlling the alloying elements Fe and Si and optimizing the design of material selection and the composition of the main alloying elements.

[0015] 2. In this invention, by selectively combining the "crystal structure + solidification structure" of pure aluminum rolled strip and controlling the efficient heat conduction process during continuous online heat treatment, as well as the rolling deformation during hot and cold continuous rolling, aluminum foil with high conductivity, uniform structure and flat plate shape is obtained.

[0016] 3. In this invention, the length of the aluminum foil is detected by utilizing the conductive properties of the aluminum foil itself after the finished aluminum foil is slit, and the detection is stable, reliable and highly accurate.

[0017] 4. In this invention, a sponge is used to contact the aluminum foil, and then positive and negative pressure is used to flatten or adsorb the aluminum foil. This can avoid damage to the aluminum foil during testing and ensure that the aluminum foil is tested in a flat state, thus ensuring the accuracy of the test results.

[0018] 5. In this invention, when inspecting finished aluminum foil products, the inspection body moves along with the aluminum foil conveyed on the production line, and the production line does not need to be stopped during inspection, thus avoiding the impact on efficiency due to line stoppage. Attached Figure Description

[0019] Figure 1 This is a perspective view of the present invention; Figure 2 This is a schematic diagram of the housing configuration in this invention; Figure 3 This is a schematic diagram of the sponge arrangement in this invention; Figure 4 This is a cross-sectional view of the shell in this invention; Figure 5 This is an enlarged view of point A in this invention; Figure 6 This is a schematic diagram of the aluminum foil arrangement in this invention; Figure 7 This is a schematic diagram of the telescopic rod configuration in this invention; Figure 8 This is a schematic diagram of the cross brace arrangement in this invention; Figure 9 This is a schematic diagram of the strip wave in this invention.

[0020] Reference numerals in the attached drawings: 1. Housing; 2. Movable plate; 3. Test copper sheet; 4. Electric cylinder one; 5. Support; 6. Lifting cylinder; 7. Limiting frame; 8. Limiting block; 9. Horizontal support rod; 10. Limiting slide groove; 11. Partition plate; 12. Pad frame; 13. Sponge; 14. Sealing film; 15. Through port; 16. Mounting groove; 17. Air inlet pipe; 18. Air extraction pipe; 19. Threaded sleeve; 20. Sliding sleeve; 21. Lead screw; 22. Sliding rod; 23. Shaft seat; 24. Support platform; 25. Motor; 26. Base; 27. Lifting column; 28. Electric cylinder two; 29. ​​Binocular camera; 30. Support frame; 31. Linear module; 32. Slide table; 33. Aluminum foil body. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0022] This application provides an aluminum foil for lithium batteries and a method for preparing the same, and provides the following technical solution, which will be discussed in conjunction with the following. Figures 1-8 Please provide a detailed explanation: An aluminum foil for lithium batteries comprises the following components by mass percentage: Si: 0.06%-0.09%; Fe: 0.10%-0.15%; Cu: 0.04%-0.05%; Mn: 0.01%; Mg: 0.01%; Cr: 0.01%; Zn: 0.01%; Ti: 0.02%-0.03%; Al ≥ 99.60%, with the balance being impurities.

[0023] The above-mentioned method for preparing aluminum foil includes the following steps: S1: Composition blending and casting. Pure aluminum, Fe, Si and Cu intermediate alloy materials are loaded into a melting furnace for melting and slag removal. After melting, it is transferred to refining. During refining, samples are taken to analyze the composition. After the composition is qualified, it is cast into aluminum ingots.

[0024] S2: Ingot rolling. The aluminum ingot obtained in the previous step is heated and then hot rough rolling is performed. After hot rough rolling, finish rolling is performed to roll the aluminum alloy strip to a thickness of 6mm-7mm. Then, four passes of cold rolling are performed to process the finished thickness to 80%-92%. Then, intermediate annealing is performed using an air cushion continuous annealing furnace. After annealing and cooling, two passes of cold rolling are performed.

[0025] S3: Foil rolling, which involves four passes of foil rolling. First, three passes of foil rolling are performed, followed by 24 hours of cooling, and then the remaining foil rolling is performed until the desired thickness is achieved.

[0026] S4: Inspection and Packaging. After the aluminum foil is cut from the rolling mill, it is transferred to the slitting machine for cutting into rolls of the required width. The aluminum foil on the rolls is then slit into individual aluminum foils. An online detection device is used to check the length of the individual aluminum foils. Once the inspection is qualified, they can be packaged.

[0027] like Figure 3-6 As shown, the online testing device includes a square housing 1, which is installed on a testing production line. An aluminum foil body 33 is placed on the testing production line, and the housing 1 is located directly above the aluminum foil body 33. The front end of the housing 1 facing the material inlet direction of the production line and the rear end facing away from the material inlet direction of the production line are both pre-set with openings 15. A movable plate 2 is installed in the opening 15. Multiple test copper plates 3 are bolted to the bottom of the side of the movable plate 2 facing the middle of the housing 1. The movable plate 2 is insulated. Wires are welded between the front and rear test copper plates 3. A switch, a load and a power supply are connected in series on the wires. Wires are also welded between adjacent test copper plates 3 at the front and rear ends of the housing 1. A switch, a load and a power supply are connected in series on the wires. The power supply outputs a current of 10μA. The top of the movable plate 2 extends above the housing 1. Supports 5 are bolted to both the front and rear of the top of the housing 1. An electric cylinder 4 is bolted to the top of the support 5. The output end of the electric cylinder 4 is bolted to the middle top position of the movable plate 2. A mounting groove 16 is pre-set on the housing 1 below the support 5. A lifting cylinder 6 is bolted to the mounting groove 16. The support 5 is bolted to the output end of the lifting cylinder 6.

[0028] After being slit, the entire roll of aluminum foil is cut into different quantities of rolls of the required width. The aluminum foil on each roll is then slit into individual aluminum foil pieces. The finished aluminum foil bodies 33 are conveyed on the production line. When the length of the aluminum foil body 33 is being checked, the housing 1 is vertically aligned with the aluminum foil body 33, and then the housing 1 is pressed onto the aluminum foil body 33 and held stationary. Then, the lifting cylinder 6 is controlled to retract and descend, causing the electric cylinder 4 and the movable plate 2 connected to the electric cylinder 4 to descend. The descent stops at the maximum position, ensuring that the height of the test copper sheet 3 can contact the aluminum foil body 33. Then, the control... Electric cylinder 4 operates, retracting from its initial, fully extended position, which moves the two fixed movable plates 2 towards the center until the test copper plates 3 at either end of the housing 1 simultaneously contact the aluminum foil body 33. When either test copper plate 3 contacts the aluminum foil body 33, a circuit is established between adjacent test copper plates 3 at that end because the aluminum foil body 33 is a conductor. At this point, the load on the connected circuit enters a working state, indicating that the test copper plate 3 at that end is in contact with the aluminum foil body 33. Electric cylinder 4 at that end immediately stops. The other end is not connected to the circuit, indicating that the other end is not in contact. The test copper piece 3 is not in contact with the aluminum foil body 33. The electric cylinder 4 at the other end continues to work, causing the output end to retract until the test copper piece 3 at the other end also contacts the aluminum foil body 33. The circuit of the adjacent test copper piece 3 at the other end is connected, indicating that it is in contact with the aluminum foil body 33. The electric cylinder 4 at that end is also immediately stopped. At this time, the test copper pieces 3 at both ends are in contact with the aluminum foil body 33, and the circuit between the two test copper pieces 3 is connected by the aluminum foil body 33. The load on this circuit starts to work, indicating that the test copper pieces 3 at both ends are in contact with the aluminum foil body 33. At this time, the retraction displacement distance of the electric cylinders 4 at both ends is read, and the movable plate is moved. The length of the aluminum foil body 33 can be obtained by subtracting the retraction displacement from the initial position spacing of 2. For example, if the retraction displacements of the electric cylinders 4 at both ends are a1 and a2 respectively, and the initial position spacing of the movable plates 2 at both ends is L, the length of the aluminum foil body 33 is L-(a1+a2). The positioning accuracy of the electric cylinders can reach ±0.01mm, which can meet the size inspection of aluminum foil for lithium batteries. When the test result is qualified, it means that the size of the aluminum foil body 33 being tested is qualified and can continue to be conveyed on the production line, and finally enter the packaging or use station. When the test result is unqualified, the unqualified aluminum foil body 33 is removed from the production line.

[0029] like Figure 7 and Figure 8 As shown, horizontal support rods 9 are bolted to both ends of the movable plate 2 facing the housing 1. Square limiting blocks 8 are movably sleeved on the horizontal support rods 9. A limiting frame 7 is bolted to the top of the housing 1 at the position perpendicular to the horizontal support rods 9. A limiting groove 10 is preset in the limiting frame 7. The limiting block 8 is located in the limiting groove 10 and is movably sleeved up and down.

[0030] The movable plate 2 is supported by the electric cylinder 4, but the support force may be insufficient and the support point is singular, resulting in uneven force on the movable plate 2 and possible swaying. After setting the cross brace 9, additional support points are obtained, which are located in the middle and at both ends of the movable plate 2, distributing the force and ensuring stability. The cross brace 9 is sleeved with the limiting block 8. When the electric cylinder 4 drives the movable plate 2 to move laterally, the cross brace 9 can move laterally within the limiting block 8 to meet the movement requirements of the movable plate 2 without causing interference or obstruction. At the same time, the limiting block 8 is sleeved within the limiting groove 10 of the limiting frame 7. When the lifting cylinder 6 works to drive the movable plate 2 to rise or fall, the limiting block 8 moves up and down within the limiting groove 10 to meet the rising and falling requirements of the movable plate 2 without causing interference or obstruction.

[0031] like Figure 3-5 As shown, a partition 11 is integrally formed and fixed in the middle position inside the housing 1. A pad frame 12 is integrally formed and fixed at the bottom of the partition 11. A sponge 13 is installed inside the housing 1 at the bottom of the pad frame 12. The sponge 13 is fixed to the pad frame 12 with adhesive. An edge sealing film 14 is fixed to the side of the sponge 13 with adhesive. The bottom surface of the sponge 13 is pressed on the aluminum foil body 33. An air inlet pipe 17 and an air extraction pipe 18 are installed in the middle position of the top of the housing 1 by bolts. One end of the air inlet pipe 17 and the air extraction pipe 18 both pass through the partition 11 and extend between the partition 11 and the sponge 13. The other end of the air inlet pipe 17 and the air extraction pipe 18 are respectively connected to the input end of the gas booster pump and the vacuum pump.

[0032] The sponge 13 is pressed onto the surface of the aluminum foil body 33, flattening it for testing in a flat state to ensure accurate results. The sponge 13 is also compressible and soft, reducing the possibility of damage to the aluminum foil body 33 when pressed. As the housing 1 descends to press onto the aluminum foil body 33, a gas booster pump is simultaneously activated. The gas booster pump draws in ambient air, pressurizes it, and sends it along the air inlet pipe 17 between the partition 11 and the sponge 13. Because the sponge 13 has... It has breathable properties, and the sides of the sponge 13 are blocked by the sealing film 14. The top is the air intake, and the bottom naturally forms the air outlet. The gas passes through the sponge 13 and blows downward from the bottom of the sponge 13. As the shell 1 approaches the aluminum foil body 33, the blown gas acts on the aluminum foil body 33. The downward pressure of the gas flattens the aluminum foil body 33. Then the sponge 13 presses on the aluminum foil body 33 to prevent the surface of the aluminum foil body 33 from being uneven. After the sponge 13 is pressed down, the aluminum foil body 33 will be folded. When the sponge 13 is pressed onto the aluminum foil body 33, the control gas booster pump stops, and the vacuum pump is turned on. The working input end of the vacuum pump generates negative pressure, and the air between the partition 11 and the sponge 13 is drawn from the suction pipe 18. Similarly, the side of the sponge 13 is blocked by the sealing film 14, so the gas can only be attracted from the bottom. The gas is attracted and passes through the sponge 13 from the bottom. When the gas is attracted at the bottom of the sponge 13, the negative pressure suction will also attract the aluminum foil body 33 to stick tightly to the bottom surface of the sponge 13. As long as the theoretical suction volume is greater than the actual intake volume, sufficient negative pressure suction can be generated to maintain the operation of the vacuum pump. Then the housing 1 is lifted to attract the aluminum foil body 33 away from the production line surface. At this time, the lifting cylinder 6 works again, driving the movable plate 2 to descend. At this time, the movable plate 2 can descend more, so that the aluminum foil body 33 corresponds to the middle position of the test copper sheet 3, ensuring that the test copper sheet 3 can contact the aluminum foil body 33.

[0033] like Figure 2 As shown, threaded sleeves 19 and sliding sleeves 20 are bolted to the top of the housing 1 at the front and rear ends, respectively. A lead screw 21 and a sliding rod 22 pass through the threaded sleeve 19 and the sliding sleeve 20, respectively. The lead screw 21 is threaded to the threaded sleeve 19, and the sliding rod 22 is movably sleeved to the sliding sleeve 20. The lead screw 21 and the sliding rod 22 are located above the assembly line. Support platforms 24 are installed below the two ends of the lead screw 21 and the sliding rod 22. A bearing seat 23 is bolted to the top of the support platform 24. The two ends of the lead screw 21 and the sliding rod 22 are sleeved to the bearing seat 23. A motor 25 is bolted to the support platform 24 at one end of the lead screw 21. The output end of the motor 25 is plugged into the lead screw 21.

[0034] During testing, housing 1 is positioned above the production line. When the test is successful, the vacuum pump stops, and due to the lack of negative pressure, the aluminum foil body 33 falls naturally, allowing the currently successful aluminum foil body 33 to be placed back on the production line. When the test fails, the motor 25 is activated to rotate the lead screw 21. The lead screw 21 is threadedly connected to the threaded sleeve 19, and since the lead screw 21 is fixed, it ultimately moves housing 1 along the lead screw 21, moving housing 1 away from the production line. After leaving the production line, the vacuum pump stops, and the aluminum foil body 33 falls naturally, landing outside the production line. A defective product collection box is placed below to collect the detected defective products. As the aluminum foil body 33 falls, the motor 25 reverses, causing housing 1 to move back above the production line for reset.

[0035] like Figure 2As shown, a base 26 is installed directly below the support platform 24. Lifting columns 27 are welded and fixed to both ends of the top of the base 26. The top of the lifting column 27 is installed to the support platform 24 by bolts. The lifting column 27 includes two columns, one thick and one thin. The thin column is inserted into the thick column to form a vertically movable support. An electric cylinder 28 is installed in the middle of the top of the base 26 by bolts. The output end of the electric cylinder 28 is installed to the base 26 by bolts. A binocular camera 29 is installed in the middle of the front end of the housing 1 by bolts.

[0036] Before inspection, the binocular camera 29 first identifies the aluminum foil body 33 on the production line. Then, based on the identified position of the aluminum foil body 33, the motor 25 drives the housing 1 to move, moving the housing 1 directly above the aluminum foil body 33. Then, the electric cylinder 28 retracts and stops at its lowest position, causing the support platform 24 and the housing 1 supported by the support platform 24 to descend, thereby pressing the sponge 13 onto the aluminum foil body 33. When the vacuum pump is turned on, the electric cylinder 28 lifts again, causing the housing 1 to rise and reset. When the aluminum foil body 33 passes the inspection, the electric cylinder 28 retracts, causing the aluminum foil body 33 to fall back onto the production line. At this time, the vacuum pump stops to prevent the aluminum foil body 33 from floating off the production line.

[0037] like Figure 1 As shown, a support frame 30 is installed below the base 26, and a linear module 31 is installed on the top of the support frame 30 by bolts. A slide table 32 that slides along the linear module 31 is threadedly connected to the linear module 31, and the base 26 is installed on the slide table 32 by bolts.

[0038] When the aluminum foil body 33 is conveyed by the production line, it is first identified by the binocular camera 29. After the motor 25 works to align the housing 1 with the aluminum foil body 33, the linear module 31 is controlled to work, maintaining the same moving speed as the aluminum foil body 33. At this time, the electric cylinder 28 works to drive the housing 1 to descend. When the aluminum foil body 33 is being detected, the production line does not need to stop and can maintain a continuous conveying state. By setting up multiple detections on the production line for coverage, detection can be performed without stopping the machine, avoiding the impact of downtime on efficiency.

[0039] Furthermore, during the above testing process, the test data is collected and recorded. The staff can input the test data into the following formula to calculate the relevant data of the board shape. The staff can then analyze whether the board shape is defective based on the obtained data. Flatness (fatness), also known as straightness I Defined as: I =(L+∆LL / L)*10 5 =∆L / L*10 5 If the calculated result is 20, then the flatness of the rolled piece is said to be 20. I unit.

[0040] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An aluminum foil for a lithium battery, characterized by, The components include the following mass percentages: Si: 0.06%-0.09%; Fe: 0.10%-0.15%; Cu: 0.04%-0.05%; Mn: 0.01%; Mg: 0.01%; Cr: 0.01%; Zn: 0.01%; Ti: 0.02%-0.03%; Al≥99.60%, and the balance is impurities. The components include the following mass percentages: Si: 0.06%-0.09%; Fe: 0.10%-0.15%; Cu: 0.04%-0.05%; Mn: 0.01%; Mg: 0.01%; Cr: 0.01%; Zn: 0.01%; Ti: 0.02%-0.03%; Al≥99.60%, and the balance is impurities.

2. A method for producing an aluminum foil for a lithium battery using the aluminum foil for a lithium battery according to claim 1, characterized by, The method comprises the following steps: S1: ingredient preparation casting, pure aluminum and Fe, Si and Cu intermediate alloy ingredients are loaded into a smelting furnace for smelting and slagging, after smelting, the molten metal is transferred to a refining furnace for refining, during refining, the composition of the molten metal is analyzed, and after the composition is qualified, the molten metal is cast into aluminum ingots, S2: flat ingot rolling, the aluminum flat ingot obtained in the previous step is heated, after heating, hot rough rolling is performed, after hot rough rolling, 3-stand continuous rolling is performed, the aluminum alloy strip is rolled to a thickness of 6-7 mm, then cold rolling is performed in 4 passes, the thickness of the product is reduced to 80%-92%, then intermediate annealing is performed using a gas cushion type continuous annealing furnace, after annealing and cooling, cold rolling is performed in 2 passes, S3: foil rolling, 4 passes of foil rolling are performed, wherein, 3 passes of foil rolling are first performed, then the foil is cooled for 24 h, the remaining foil rolling is then performed, and the foil is finally rolled to the required thickness, S4: inspection and packaging, after the aluminum foil is discharged from the rolling mill, it is transferred to a slitting machine for slitting, and is cut into rolls of the required width, the aluminum foil on the rolls is then slit into individual aluminum foils, the length of the individual aluminum foils is checked using an online detection device, and the aluminum foils are packaged after passing the inspection.

3. The method for preparing aluminum foil for lithium batteries according to claim 2, characterized in that, The online detection device comprises a square housing (1), the front end and the rear end of the housing (1) are provided with through openings (15), the through openings (15) are provided with movable plates (2), a plurality of test copper sheets (3) are arranged on the movable plates (2) and face the middle side of the housing (1), wires are connected between the front and rear test copper sheets (3), switches, loads and power sources are connected in series on the wires, and wires are connected between the adjacent test copper sheets (3) at the front end and the rear end of the housing (1), and switches, loads and power sources are connected in series on the wires. The top of the movable plate (2) extends above the housing (1), supports (5) are arranged at the top of the housing (1), an electric cylinder one (4) is arranged at the top of the supports (5), the output end of the electric cylinder one (4) is connected to the middle top of the movable plate (2), an installation groove (16) is arranged in the housing (1) below the supports (5), a jacking cylinder (6) is arranged in the installation groove (16), and the supports (5) and the output end of the jacking cylinder (6) are connected.

4. The method for preparing aluminum foil for lithium batteries according to claim 3, characterized in that, Square limiting blocks (8) are movably sleeved on the horizontal support rods (9) at both ends of the side of the housing (1) facing the housing (1), limiting frames (7) are arranged at the positions vertically corresponding to the horizontal support rods (9) at the top of the housing (1), limiting sliding grooves (10) are arranged in the limiting frames (7), and the limiting blocks (8) are movably sleeved in the limiting sliding grooves (10).

5. The method for preparing aluminum foil for lithium batteries according to claim 3, characterized in that, The middle position in the shell (1) is fixed with a partition (11), the bottom of the partition (11) is fixed with a cushion frame (12), the bottom of the cushion frame (12) is installed with a sponge (13) in the shell (1), the side of the sponge (13) is fixed with an edge film (14), the top of the shell (1) is installed with an air inlet pipe (17) and an air outlet pipe (18), one end of the air inlet pipe (17) and the air outlet pipe (18) penetrates the partition (11) and extends to the space between the partition (11) and the sponge (13), the other end of the air inlet pipe (17) and the air outlet pipe (18) is connected with the input end of the gas booster pump and the vacuum air extractor respectively.

6. The method for preparing aluminum foil for lithium batteries according to claim 3, characterized in that, The top of the shell (1) is installed with a threaded sleeve (19) and a sliding sleeve (20) at the front and rear ends respectively, the threaded sleeve (19) and the sliding sleeve (20) are respectively penetrated by a lead screw (21) and a sliding rod (22), the lead screw (21) is threadedly connected with the threaded sleeve (19), the sliding rod (22) is movably sleeved with the sliding sleeve (20), the two ends of the lead screw (21) and the sliding rod (22) are installed with a support table (24), the top of the support table (24) is installed with an axle seat (23), the two ends of the lead screw (21) and the sliding rod (22) are sleeved with the axle seat (23), the support table (24) on one end of the lead screw (21) is installed with a motor (25), the output end of the motor (25) is plug-in connected with the lead screw (21).

7. The method for preparing aluminum foil for lithium batteries according to claim 6, characterized in that, The bottom of the support table (24) is installed with a base (26), the top of the base (26) is fixed with a lifting column (27) at both ends, the top of the lifting column (27) is installed between the support table (24), the top of the base (26) is installed with an electric cylinder two (28) at the middle position, the output end of the electric cylinder two (28) is installed with the base (26), the front end of the shell (1) is installed with a binocular camera (29).

8. The method for preparing aluminum foil for lithium batteries according to claim 7, characterized in that, The bottom of the base (26) is installed with a support frame (30), the top of the support frame (30) is installed with a linear module (31), the linear module (31) is threadedly connected with a sliding table (32) sliding along the linear module (31), the base (26) is installed on the sliding table (32).

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