A high-strength aluminum foil for high-energy batteries and a preparation method thereof

Abstract

The invention discloses a high-strength aluminum foil for high-dur batteries and a preparation method thereof, and belongs to the technical field of aluminum foil preparation. Its composition and weight percentage are as follows: Fe: 0.47-0.52%, Si: 0.10-0.15%, Mn: 0.06-0.08%, Cu: 0.06-0.10%, Mg: 0.01-0.02%, Ti: 0.02-0.04%, the total content of other inevitable elements is ≤0.15%, and the balance is Al. Its preparation method includes: raw material melting and casting, primary cold rolling, annealing, secondary cold rolling, foil rolling and fine cutting, etc. The invention improves the mechanical properties of aluminum foil by optimizing and controlling the alloy composition of the material coil, the calendering process, the homogenization annealing process, the corona and the fine cutting process, and produces a 0.01-0.015mm thick double-sided smooth aluminum foil with a tensile strength of ≥250Mpa, a dyne value of ≥36dyn, and a cutting edge burr length of ≤50um.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum foil preparation, and particularly relates to a high-strength, high-dyne aluminum foil for batteries and a preparation method thereof; the prepared aluminum foil has a tensile strength of ≥250MPa and a surface dyne value of ≥36dyn. Background Art

[0002] With the continuous development of new energy vehicles, the battery industry with aluminum foil as the current collector of the positive electrode material has flourished, and battery aluminum foil has also become a product with high added value in the aluminum processing industry. In the prior art, the common 1100 aluminum alloy can be used to prepare aluminum foil. 1100 aluminum alloy is ordinary industrial pure aluminum with an aluminum content of 99.0%. It has low strength, but has good ductility, formability, weldability and corrosion resistance. However, for battery aluminum foil, the aluminum foil obtained by using 1100 aluminum alloy and corresponding processes has problems such as soft strength and low surface dyne value, which directly affects the various performances of the battery. When the tensile strength is low, the electrode coated with active material is prone to breakage during the flattening process such as roller calendering; the surface dyne value of aluminum foil is small, which seriously affects the subsequent coating uniformity and compaction performance of lithium batteries. Summary of the invention

[0003] In order to solve the above problems, the embodiment of the present invention provides a high-strength, high-dyne aluminum foil for batteries and a preparation method thereof. The prepared battery aluminum foil has the advantages of high strength and high dyne value, and can improve the battery aluminum foil during the battery manufacturing process. The problem of broken strips caused by insufficient strength and the problem of coating leakage caused by low surface dyne value. The technical solution is as follows:

[0004] On the one hand, an embodiment of the present invention provides a high-strength, high-density aluminum foil for batteries, the composition and weight percentage of which are as follows:

[0005] Fe: 0.47-0.52%, Si: 0.10-0.15%, Mn: 0.06-0.08%, Cu: 0.06-0.10%, Mg: 0.01-0.02%, Ti: 0.02-0.04%, the total content of other unavoidable elements is ≤ 0.15%, and the balance is Al. The composition and content of this patent are improved on the basis of 1100 alloy to obtain high tensile strength and high value.

[0006] Preferably, the high-strength, high-dyne aluminum foil for batteries provided by the present invention has the following composition and weight percentage: Fe: 0.48%, Si: 0.12%, Mn: 0.065%, Cu: 0.07%, Mg: 0.012%, Ti: 0.03%, the total content of other unavoidable elements is ≤ 0.15%, and the balance is Al. The aluminum foil has high tensile strength and high dyne value.

[0007] Preferably, the high-strength, high-dyne aluminum foil for batteries provided by the present invention has the following composition and weight percentage: Fe: 0.50%, Si: 0.13%, Mn: 0.07%, Cu: 0.07%; Mg: 0.012%; Ti: 0.035%; the total content of other unavoidable elements is ≤ 0.15%, and the balance is Al. The aluminum foil has a high dyne value and a very high tensile strength.

[0008] The above two products can be selected according to actual needs.

[0009] On the other hand, an embodiment of the present invention further provides a method for preparing the aforementioned high-strength, high-density aluminum foil for batteries, the method comprising:

[0010] S101 Raw material melting and casting: Put the raw materials into the melting furnace according to the proportion, control the temperature of the aluminum melt to 710-740℃, the hydrogen content in the melt is ≤0.12ml / 100gAl, and use the casting and rolling method to obtain 6.0-7.0mm thick aluminum coils.

[0011] S102: First cold rolling: The aluminum coil obtained in step S101 is subjected to one cold rolling to a thickness of 3.6-4.2 mm.

[0012] S103 annealing: the aluminum coil obtained in step S102 is subjected to homogenization annealing at 540-560°C for 24-26 hours; after the annealing process, the grains of the aluminum coil undergo recovery and recrystallization, so that the coarse fiber grains are refined, a uniform and fine grain structure is obtained, and homogenization annealing is achieved.

[0013] S104 secondary cold rolling: The aluminum coil obtained in step S103 is cold rolled through 4 passes to a thickness of 0.20-0.24 mm.

[0014] S105 foil rolling: the aluminum coil obtained in step S104 is rolled through four passes to obtain an aluminum foil with a thickness of 0.010-0.015 mm.

[0015] S106 fine slitting: The aluminum foil obtained in step S105 is slit into small rolls by a slitting machine, then subjected to corona treatment, and finally finely cut by a fine cutting machine to obtain aluminum foil of predetermined specifications.

[0016] Step S101 specifically includes: the molten aluminum melt is refined in the furnace, degassed and filtered online, and then flows through the flow channel to the front box, and then flows through the casting nozzle into the casting and rolling area and is rolled by the rotating roller to obtain an aluminum coil with a thickness of 6.0-7.0 mm. The temperature of the front box is 690-705°C, the length of the casting and rolling area is 50-55 mm, and the casting and rolling speed is 500-600 mm / min.

[0017] Wherein, step S102 specifically includes: the roughness of the cold rolling working roll is 0.6-0.8um; the convexity of the cold rolling upper working roll is 0.015mm, and the convexity of the lower working roll is 0.

[0018] Wherein, step S104 specifically includes: the roughness of the working rolls in the first three passes is 0.5-0.6um, and the convexity is 0.02mm; the roughness of the working rolls in the last pass is 0.40-0.45um, and the convexity is 0.03mm.

[0019] Among them, in step S102 and step S104, the additives used in the rolling oil are conventional additives (such as mainly alcohol additives).

[0020] Wherein, step S105 specifically includes: the roughness of the working rolls in the first two passes is 0.22-0.28 μm, and the convexity is 0.04-0.06 mm; the roughness of the working rolls in the third pass is 0.13-0.18 μm, and the convexity is 0.06-0.08 mm; the roughness of the working rolls in the fourth pass is 0.09-0.13 μm, and the convexity is 0.07-0.10 mm. Preferably, the additive used in the rolling oil during the foil rolling process is a Goudaine additive (a commercially available product, specifically a Goudaine additive of model MARK625W3H produced by Shijiazhuang Xintai Special Oil Co., Ltd.), and the temperature of the rolling oil is ≥45°C.

[0021] Wherein, step S106 specifically includes: the power of the corona machine is 45-60 kwh. The precision cutting speed is 120-180 m / min. Controlling the precision cutting speed can improve the dyne value of the aluminum foil surface to a certain extent.

[0022] Preferably, in step S106, anhydrous alcohol is used to lubricate the disc cutter during the fine cutting process, and the alcohol is evenly titrated at a rate of 1-2 drops / second through a controllable burette with a tube diameter of 1-2 mm, and the alcohol titration is performed in the opposite direction of the running of the disc cutter. In the fine cutting process, the burr length of the aluminum coil end surface obtained by the above means is ≤50um.

[0023] Further, step S106 also includes: the aluminum foil obtained in step S105 is cut into small rolls after the shape is detected by an offline shape meter, and the detection tension of the offline shape meter is 0.8kg / mm 2 , the plate collapse amount is ≤5mm.

[0024] Specifically, the preparation method provided by the embodiment of the present invention comprises:

[0025] S101 Raw material melting and casting: put the raw materials into the melting furnace according to the proportion, control the temperature of the aluminum melt to 710-740℃, and the hydrogen content in the melt is ≤0.12ml / 100gAl. The molten aluminum melt is refined in the furnace, degassed and filtered online, and then flows through the flow channel to the front box, and then flows into the casting and rolling area through the casting nozzle and rolled by rotating rollers to obtain 6.0-7.0mm thick aluminum coils; the temperature of the front box is 690-705℃, the length of the casting and rolling area is 50-55mm, and the casting and rolling speed is 500-600mm / min.

[0026] S102 one-pass cold rolling: the aluminum coil obtained in step S101 is subjected to one pass of cold rolling to a thickness of 3.6-4.2 mm; the roughness of the cold rolling working roll is 0.6-0.8 um, the convexity of the cold rolling upper working roll is 0.015 mm, and the convexity of the lower working roll is 0.

[0027] S103 annealing: the aluminum coil obtained in step S102 is subjected to homogenization annealing treatment at 540-560° C. for 24-26 hours.

[0028] S104 secondary cold rolling: The aluminum coil obtained in step S103 is cold rolled to a thickness of 0.20-0.24 mm through 4 passes. The roughness of the working rolls in the first 3 passes is 0.5-0.6 um, the convexity is 0.02 mm, and the roughness of the working rolls in the last pass is 0.40-0.45 um, and the convexity is 0.03 mm.

[0029] S105 Foil rolling: The aluminum coil obtained in step S104 is rolled through 4 passes to obtain an aluminum foil with a thickness of 0.01-0.015 mm. The roughness of the working rolls in the first two passes is 0.22-0.28 μm, and the convexity is 0.04-0.06 mm; the roughness of the working rolls in the third pass is 0.13-0.18 μm, and the convexity is 0.06-0.08 mm; the roughness of the working rolls in the fourth pass is 0.09-0.13 μm, and the convexity is 0.07-0.10 mm. Preferably, the additive used in the rolling oil during the foil rolling process is a Goudaine additive, and the temperature of the rolling oil is ≥45°C.

[0030] S106 Fine Cutting: The aluminum foil obtained in step S105 is tested for shape by an offline shape meter, and the detection tension of the offline shape meter is 0.8 kg / mm 2 , the plate type collapse amount is ≤5mm. Then it is cut into small rolls by a slitting machine. Then it is treated with corona, and the power of the corona machine is 45-60kwh. Finally, the aluminum foil of predetermined specifications is obtained by fine cutting by a fine cutting machine, and the fine cutting speed is 120-180m / min. Preferably, anhydrous alcohol is used to lubricate the disc knife during the fine cutting process, and the alcohol is evenly titrated at a speed of 1-2 drops / second through a controllable burette with a tube diameter of 1-2mm, and the alcohol titration is carried out in the opposite direction of the operation of the disc knife.

[0031] The present invention has the following advantages: by optimizing and controlling the alloy composition of the material coil, the rolling process and the homogenization annealing process, the mechanical properties of the aluminum foil are improved, and fine and dense grains are obtained, and the tensile strength of the double-sided smooth aluminum foil with a thickness of 0.01-0.015mm is produced. ≥250Mpa (usually 200-250MPa in the prior art); by controlling the roughness of the working roll to gradually decrease to form a drop, and with special lubricating oil, the amount of aluminum powder falling off the surface of the battery foil during the rolling process is gradually reduced, thereby improving the dyne value of the battery foil surface, and the dyne value of the aluminum foil rolling mill is ≥31dyn (usually 28-30dyn in the prior art). By controlling the power of the corona equipment, the precision cutting speed and the lubrication method of the cutter during the fine cutting process, the dyne value of the battery aluminum foil finished product is obtained. ≥36dyn (usually 33-34dyn in the prior art), the length of the cutting edge burr is ≤50um. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flow chart of a method for preparing a high-strength, high-energy aluminum foil for batteries provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0034] Example 1

[0035] Example 1 provides a method for preparing a high-strength aluminum foil for a high-energy battery, comprising the following steps:

[0036] S101 raw material melting and casting: feed according to the following mass percentages: Fe: 0.48%, Si: 0.12%, Mn: 0.065%, Cu: 0.07%, Mg: 0.012%, Ti: 0.03%, the total content of other unavoidable elements ≤ 0.15%, and the balance is Al.

[0037] The temperature of the aluminum melt is controlled at 720℃, and the aluminum melt is obtained after melting. The hydrogen content in the aluminum melt is controlled to be 0.11ml / 100gAl. After the melt is refined in the furnace, degassed online and filtered, it flows through the flow channel to the front box, and then flows into the casting and rolling area through the casting nozzle and is rolled by the rotating roller to obtain a 6.4mm thick aluminum coil. The temperature of the front box of the casting and rolling is 698℃, the length of the casting and rolling area is 52mm, and the casting and rolling speed is 520mm / min.

[0038] S102 Cold rolling: The aluminum coil with a thickness of 6.4 mm obtained in step S101 is subjected to one cold rolling to a thickness of 3.8 mm; the roughness of the cold rolling working roll is 0.7 um, the convexity of the cold rolling upper working roll is 0.015 mm, and the convexity of the lower working roll is 0.

[0039] S103 annealing: the aluminum coil with a thickness of 3.8 mm obtained in step S102 is subjected to homogenization annealing treatment; the homogenization annealing temperature is 550° C. and the annealing time is 26 hours.

[0040] S104 cold rolling: the coil after annealing in step S103 is cold rolled in 4 passes to a thickness of 0.22 mm; wherein the roughness of the working rolls in the first 3 passes is 0.55 um, the convexity is 0.02 mm, and the roughness of the working rolls in the last pass is 0.40 um, the convexity is 0.03 mm.

[0041] S105 Foil rolling: After the material coil with a thickness of 0.22mm obtained in step S104 is rolled through 4 passes, a double-sided smooth aluminum foil with a thickness of 0.01mm is obtained. Among them, the roughness of the working rolls in the 1st and 2nd passes of foil rolling is 0.22μm, and the convexity is 0.04mm; the roughness of the working rolls in the 3rd pass is 0.13μm, and the convexity is 0.06mm; the roughness of the working rolls in the 4th pass is 0.10μm, and the convexity is 0.08mm. The additive used in the foil rolling process is a new type of Goudaine additive, and the rolling oil temperature is 48℃.

[0042] S106 Fine Slitting: The double-sided smooth aluminum foil roll with a thickness of 0.01 mm obtained in step S105 is tested for its shape by an offline shape meter. The offline shape test tension is 0.8 kg / mm 2 , the plate type collapse is 4mm. After passing through a slitting machine with surface detection equipment, it is cut into small rolls of aluminum foil; then it passes through a corona machine with a power of 60kwh. Finally, it is cut into rolls of the required width by a fine cutting machine. Among them, the fine cutting speed is 120m / min. During the fine cutting process, anhydrous alcohol is used to lubricate the disc knife. The alcohol is evenly titrated at a speed of 1 drop / second through a controllable burette with a tube diameter of 2mm. The alcohol titration is carried out in the opposite direction of the disc knife. The length of the burr on the end face of the obtained aluminum coil is 40um.

[0043] The 0.01 mm thick aluminum foil prepared in this embodiment has a tensile strength of 255 MPa and a surface dyne value of 38 dyn, which can meet the battery's requirements for high strength and high dyne value of aluminum foil.

[0044] Example 2

[0045] Embodiment 2 provides a method for preparing a high-strength aluminum foil for a high-energy battery, comprising the following steps:

[0046] S101 raw material melting and casting: feed according to the following mass percentages: Fe: 0.50%, Si: 0.13%, Mn: 0.07%, Cu: 0.07%, Mg: 0.012%, Ti: 0.035%, the total content of other unavoidable elements is ≤0.15%, and the balance is Al.

[0047] The temperature of the aluminum melt is controlled at 720°C, and the aluminum melt is obtained after melting. The hydrogen content in the aluminum melt is controlled to be 0.115ml / 100gAl. After the melt is refined in the furnace, degassed online and filtered, it flows through the flow channel to the front box, and then flows into the casting and rolling area through the casting nozzle and is rolled by the rotating roller to obtain a 7.0mm thick aluminum coil. Among them, the temperature of the front box of the casting and rolling is 700°C, the length of the casting and rolling area is 55mm, and the casting and rolling speed is 500mm / min.

[0048] S102 cold rolling: The aluminum coil with a thickness of 7.0 mm obtained in step S101 is subjected to one cold rolling to a thickness of 4.2 mm; wherein the roughness of the cold rolling working roll is 0.7 um, the convexity of the cold rolling upper working roll is 0.015 mm, and the convexity of the lower working roll is 0.

[0049] S103 annealing: the aluminum coil with a thickness of 4.2 mm obtained in step S102 is subjected to homogenization annealing treatment; the homogenization annealing temperature is 560° C. and the annealing time is 24 hours.

[0050] S104 cold rolling: the coil after annealing in step S103 is cold rolled in 4 passes to a thickness of 0.24 mm; wherein the roughness of the working rolls in the first 3 passes is 0.55 um, the convexity is 0.02 mm, and the roughness of the working rolls in the last pass is 0.40 um, the convexity is 0.03 mm.

[0051] S105 Foil rolling: After the material coil with a thickness of 0.24mm obtained in step 104 is rolled through 4 passes, a double-sided smooth aluminum foil with a thickness of 0.012mm is obtained. Among them, the roughness of the working rolls in the 1st and 2nd passes of foil rolling is 0.24μm, and the convexity is 0.04mm. The roughness of the working rolls in the 3rd pass is 0.13μm, and the convexity is 0.06mm. The roughness of the working rolls in the 4th pass is 0.10μm, and the convexity is 0.08mm. The additive used in the foil rolling process is a new type of Goudaine additive, and the rolling oil temperature is 48°C.

[0052] S106 Fine Slitting: The double-sided smooth aluminum foil roll with a thickness of 0.012 mm obtained in step S105 is tested for its shape by an offline shape meter. The offline shape test tension is 0.8 kg / mm 2 , the plate type collapses by 4mm; then it passes through a slitting machine with surface detection equipment to be cut into small rolls of aluminum foil; then it passes through a corona machine with a power of 60kwh; finally it is cut into rolls of the width required by the customer by a fine cutting machine. Among them, the fine cutting speed is 150m / min. During the fine cutting process, anhydrous alcohol is used to lubricate the disc knife. The alcohol is evenly titrated at a speed of 1 drop / second through a controllable burette with a tube diameter of 2mm. The alcohol titration is carried out in the opposite direction of the disc knife. The length of the burr on the end face of the obtained aluminum coil is 45um.

[0053] The 0.012 mm thick aluminum foil prepared in this embodiment has a tensile strength of 265 MPa and a surface dyne value of 36 dyn, which can meet the battery's requirements for high strength and high dyne value of aluminum foil.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a high-strength aluminum foil for a high-energy battery, characterized in that: The method comprises: S101 Raw material melting and casting: put the raw materials into the melting furnace according to the proportion, control the temperature of the aluminum melt to 710-740℃, the hydrogen content in the melt is ≤0.12ml / 100gAl, and use the casting and rolling method to obtain 6.0-7.0mm thick aluminum coils; S102: cold rolling the aluminum coil obtained in step S101 to a thickness of 3.6-4.2 mm; S103 annealing: the aluminum coil obtained in step S102 is subjected to homogenization annealing at 540-560° C. for 24-26 hours; S104 secondary cold rolling: the aluminum coil obtained in step S103 is cold rolled 4 times to a thickness of 0.20-0.24 mm; S105 foil rolling: the aluminum coil obtained in step S104 is rolled through 4 passes to obtain an aluminum foil with a thickness of 0.010-0.015 mm; S106 fine slitting: the aluminum foil obtained in step S105 is slit into small rolls by a slitting machine, then subjected to corona treatment, and finally finely cut by a fine cutting machine to obtain aluminum foil of predetermined specifications; The composition and weight percentage of the aluminum alloy are as follows: Fe: 0.48%, Si: 0.12%, Mn: 0.065%, Cu: 0.07%, Mg: 0.012%, Ti: 0.03%, the total content of other unavoidable elements is ≤ 0.15%, and the balance is Al; Step S102 specifically includes: the roughness of the cold rolling work roll is 0.6-0.8 μm; the crown of the cold rolling upper work roll is 0.015 mm, and the crown of the lower work roll is 0; Step S104 specifically includes: the roughness of the working rolls in the first three passes is 0.5-0.6 μm, and the convexity is 0.02 mm; the roughness of the working rolls in the last pass is 0.40-0.45 μm, and the convexity is 0.03 mm; Step S105 specifically includes: the roughness of the working rolls in the first two passes is 0.22-0.28 μm, and the convexity is 0.04-0.06 mm; the roughness of the working rolls in the third pass is 0.13-0.18 μm, and the convexity is 0.06-0.08 mm; the roughness of the working rolls in the fourth pass is 0.09-0.13 μm, and the convexity is 0.07-0.10 mm; the additive used in the rolling oil during the foil rolling process is a Goudaine additive, and the temperature of the rolling oil is ≥45°C; Step S106 specifically includes: the power of the corona machine is 45-60kwh; the fine cutting speed is 120-180m / min, and anhydrous alcohol is used to lubricate the disc knife during the fine cutting process. The alcohol is evenly titrated at a speed of 1-2 drops / second through a controllable burette with a tube diameter of 1-2mm, and the alcohol titration is carried out in the opposite direction of the disc knife.

2. The preparation method according to claim 1, characterized in that: Step S101 specifically includes: the molten aluminum melt is refined in the furnace, degassed and filtered online, then flows through the flow channel to the front box, and then is diverted through the casting nozzle into the casting and rolling area and rolled by rotating rollers to obtain an aluminum coil with a thickness of 6.0-7.0 mm; the temperature of the front box is 690-705°C, the length of the casting and rolling area is 50-55 mm, and the casting and rolling speed is 500-600 mm / min.

3. The preparation method according to claim 1, characterized in that: Step S106 also includes: the aluminum foil obtained in step S105 is cut into small rolls after the shape is detected by an offline shape meter, and the detection tension of the offline shape meter is 0.8kg / mm 2 , the plate collapse amount is ≤5mm.

4. The preparation method according to claim 1, characterized in that: The method comprises: S101 Raw material melting and casting: put the raw materials into the melting furnace according to the proportion, control the temperature of the aluminum melt to 710-740℃, and the hydrogen content in the melt is ≤0.12ml / 100gAl. The molten aluminum melt is refined in the furnace, degassed and filtered online, and then flows through the flow channel to the front box, and then flows into the casting and rolling area through the casting nozzle and rolled by the rotating roller to obtain a 6.0-7.0mm thick aluminum coil; the temperature of the front box is 690-705℃, the length of the casting and rolling area is 50-55mm, and the casting and rolling speed is 500-600mm / min; S102: cold rolling once: the aluminum coil obtained in step S101 is cold rolled once to a thickness of 3.6-4.2 mm; the roughness of the cold rolling working roll is 0.6-0.8 μm; the crown of the cold rolling upper working roll is 0.015 mm, and the crown of the lower working roll is 0; S103 annealing: the aluminum coil obtained in step S102 is subjected to homogenization annealing at 540-560° C. for 24-26 hours; S104 secondary cold rolling: the aluminum coil obtained in step S103 is cold rolled to a thickness of 0.20-0.24 mm through 4 passes, the roughness of the working rolls in the first 3 passes is 0.5-0.6 μm, the convexity is 0.02 mm, and the roughness of the working rolls in the last pass is 0.40-0.45 μm, and the convexity is 0.03 mm; S105 foil rolling: the aluminum coil obtained in step S104 is rolled through 4 passes to obtain an aluminum foil with a thickness of 0.010-0.015 mm; the roughness of the working rolls in the first 2 passes is 0.22-0.28 μm, and the convexity is 0.04-0.06 mm; the roughness of the working rolls in the third pass is 0.13-0.18 μm, and the convexity is 0.06-0.08 mm; the roughness of the working rolls in the fourth pass is 0.09-0.13 μm, and the convexity is 0.07-0.10 mm; the additive used in the rolling oil during the foil rolling process is a Goudaine additive, and the temperature of the rolling oil is ≥45°C; S106 Fine Cutting: The aluminum foil obtained in step S105 is tested for shape by an offline shape meter, and the detection tension of the offline shape meter is 0.8 kg / mm 2 , the plate collapse amount is ≤5mm; then it is cut into small rolls by a slitting machine; then it is treated with corona, and the power of the corona machine is 45-60kwh; finally, the aluminum foil of the predetermined specification is obtained by a fine cutting machine, and the fine cutting speed is 120-180m / min. During the fine cutting process, anhydrous alcohol is used to lubricate the disc knife. The alcohol is evenly titrated at a speed of 1-2 drops / second through a controllable burette with a tube diameter of 1-2mm, and the alcohol titration is carried out in the opposite direction of the disc knife.

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