Production process of aluminum foil slitting for high-efficiency high-quality lithium ion power battery

Abstract

The application discloses a production process of high-efficiency and high-quality aluminum foil slitting for lithium ion power batteries, which comprises the following steps: preparation before slitting, cleaning the slitting machine and checking whether each guide roller system is abnormal, adjusting slitting fine cutting blades and slitting lubricant; slitting, inserting the rolled aluminum foil into a feeding roll, conveying to the slitting machine under the control of tension and roller pressure at high speed, and abutting against the lower part of a disc cutter, the aluminum foil drives the disc cutter to rotate clockwise under the action of high-speed operation, the rotating speed of the disc cutter is synchronous with the slitting speed, and the speed is controlled within 180-300 m / min, so that the aluminum foil is cut, and finally, the cut aluminum foil is wound on an upper material winding shaft and a lower material winding shaft respectively. Through optimization of the production process flow, slitting fine cutting blades and slitting lubricant, the aluminum foil with stable quality for power batteries is produced, and under the premise of ensuring high efficiency, burrs and aluminum scraps are controlled within 50 mu m.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of battery aluminum foil slitting, in particular to a high-efficiency and high-quality aluminum foil slitting production process for lithium-ion power battery. BACKGROUND

[0002] Battery aluminum foil refers to aluminum foil products applied to the production of various batteries, mainly applied to 3C digital, EV power, ESS energy storage and other battery fields. This product is different from ordinary aluminum foil products, and requires high electrical conductivity, high mechanical properties and high surface quality. With the hot development of the domestic new energy market and the rapid war of battery manufacturers, the demand for battery aluminum foil has increased significantly, and it is estimated that the demand for battery foil will reach 1.2-1.6 million tons in 2025, so it is of great significance to develop high-efficiency and high-quality battery aluminum foil.

[0003] Power batteries are used in passenger cars, and electric vehicle consumers are increasingly concerned about battery safety issues. Downstream customers have higher requirements for battery safety, and battery aluminum foil, as a key carrier for the positive electrode of the battery, has the risk of piercing the separator material and causing the battery to catch fire and explode due to the sharp burrs on the cut edge of the aluminum foil after the battery is made into a cell. Therefore, the battery aluminum foil as the positive electrode material has very high requirements for the cut edge quality. In view of the fact that battery manufacturers generally pay special attention to burrs and aluminum scraps as key characteristics, most customers in the market require that the burrs and aluminum scraps of the aluminum foil cut edge be controlled within 120 microns. In recent years, the increasing energy density of batteries has led to an increasing demand for safety performance, and some battery manufacturers have proposed a requirement of ≤50 microns for aluminum foil burr and aluminum scrap control, which means that higher requirements are placed on aluminum foil precision cutting edges, increasing the difficulty of precision cutting production. Traditional strong light hand detection of aluminum scraps and burrs cannot meet the requirements, and a microscope needs to be used to accurately detect at 300-500 times magnification.

[0004] At present, most aluminum foils are first broken into strips by a slitting machine, then single-width finished products are cut to meet customer requirements, which has low production efficiency and can easily cause other surface quality problems such as pits, pockmarks, and scratches during the finishing process. The quality of the cut edge of the end face cannot be guaranteed when using the traditional slitting machine process for double-width slitting, and it cannot meet the requirements of customers. The production of high-quality cut edge aluminum foil by traditional slitting machines is difficult in the following aspects:

[0005] 1. Most of the products on the market are low-end double-zero aluminum foils produced by slitting machines, and there is no experience to refer to for slitting battery aluminum foils. In addition, the high quality requirements for the cut edge of the end face of the power battery make the requirements for the cutting edge blade slitting process even higher.

[0006] 2. High-speed operation causes damage to the blade, and the blade is prone to burrs, cuts, and wavy edges after passivation. SUMMARY

[0007] The present application aims to provide a high-efficiency and high-quality production process for slitting aluminum foil for lithium-ion power batteries, and produce stable quality aluminum foil for power batteries, control burrs and aluminum scraps within 50 μm under the premise of ensuring high efficiency.

[0008] To achieve the above-mentioned purpose, the solution of the present application is:

[0009] A high-efficiency and high-quality production process for slitting aluminum foil for lithium-ion power batteries, comprising the following steps:

[0010] S1, preparation: before slitting production, clean each guide roller system in the slitting machine thoroughly, and check whether each guide roller system is abnormal, adjust the range of slitting tension and roll pressure control;

[0011] S2, adjust the slitting fine cutting blade and the slitting lubricant: the slitting machine adopts a middle strip drawing, two edge fine cutting side, double width simultaneous slitting and winding mode, the slitting and winding mode adopts a disc cutter blade, the lower knife amount is controlled at 0.05-0.5 mm, and a volatile lubricant is used, which is mixed by base oil and industrial alcohol in proportion;

[0012] S3, slitting: insert the rolled aluminum foil into the feeding roll, convey it to the slitting machine at high speed under the control of tension and roll pressure, and abut against the lower side of the disc cutter, the aluminum foil drives the disc cutter to rotate clockwise under the action of high-speed operation, the rotating speed of the disc cutter is synchronized with the slitting speed, and the speed is controlled at 180-300 m / min, so as to realize cutting of the aluminum foil;

[0013] S4, in the slitting process of S3, the lubricant is intermittently dropped into the knife gap to cool and lubricate the disc cutter;

[0014] S5, winding: wind the cut aluminum foil on the upper and lower winding shafts respectively.

[0015] Preferably, the tension in S1 is controlled at transmission drive-30-30 N / mm 2 , shear drive-100-0 N / mm 2 , winding tension 10-60 N / mm 2 , roll pressure is controlled at 1# floating roll 1000-1800 N / m, 2# support roll 500-1200 N / m, 3# floating roll 500-1200 N / m, 4# support roll 1000-1800 N / m.

[0016] Preferably, the disc cutter in S2 is part of a cutting device in a slitting machine, the cutting device further comprising a cutter shaft and a fixed steel frame, the fixed steel frame being slidingly arranged on a transmission shaft in the middle of the slitting machine, a clamping groove being formed in the fixed steel frame, the cutter shaft being fixed on the fixed steel frame through the clamping groove and a fastening bolt, one end of the cutter shaft being provided with a roller shaft, and the disc cutter being rotatably arranged on the roller shaft and abutting against the aluminum foil.

[0017] Preferably, the fixed steel frame is adjusted in the cutting width of the aluminum foil through a hand wheel on the transmission shaft and a linear transverse guide rail.

[0018] Preferably, the disc cutter in S2 is made of tungsten steel.

[0019] Preferably, the lubricant in S2 is made by mixing base oil and industrial alcohol at a ratio of 1:1.

[0020] Preferably, the base oil in S2 is one of D40 to D60 base oil.

[0021] After the above scheme, compared with the prior art, the beneficial effects of the present application are:

[0022] The present application optimizes the production process flow, slitting and cutting blade and slitting lubricant for the aluminum foil for power battery, removes the finishing process, shortens the process flow, reduces the equipment investment, at the same time, reduces the scrap of head and tail materials, greatly reduces the production cost; the adjustment of the blade and the lubricant improves the slitting efficiency and the cutting edge quality of the aluminum foil for power battery, which can further improve the yield, and has important significance for improving the advanced cutting production level in China. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a comparison chart of the production process flow of the present application and the original aluminum foil for power battery;

[0024] Figure 2 is a comparison chart of the cutting edge end face of the aluminum foil produced by the production process of the present application and the original aluminum foil for power battery;

[0025] Figure 3 is a comparison chart of the aluminum foil produced by the production process of the present application and the original aluminum foil for power battery under 300 times magnification of a microscope;

[0026] Figure 4 is a production process flow chart of the present application;

[0027] Figure 5 is Figure 4 the partial enlarged view of A in FIG.

[0028] Label explanation: 1, slitting machine; 2, transmission shaft; 21, hand wheel; 3, fixed steel frame; 31, clamping groove; 4, cutter shaft; 5, disc cutter; 6, aluminum foil. DETAILED DESCRIPTION

[0029] The application will be described in detail below in combination with the drawings and specific examples.

[0030] The application provides a high-efficiency high-quality aluminum foil slitting production process for lithium-ion power batteries, comprising the following steps:

[0031] S1, preparation: before slitting production, each guide roller system in the slitting machine is thoroughly cleaned, and whether each guide roller system is abnormal is checked, and the range of slitting tension and roller pressure control is adjusted, as shown in Table 1;

[0032]

[0033] S2, adjusting slitting and fine cutting blades and slitting lubricant: the slitting machine adopts a slitting and winding mode of middle slitting, two sides fine cutting, and double-width simultaneous slitting, as shown in Figure 1 The application removes the finishing process, shortens the production process of the aluminum foil for power batteries, reduces the equipment investment, reduces the scrap of head and tail materials, and can greatly reduce the production cost; the slitting and winding mode adopts a disc cutter blade made of tungsten steel, and the cutter amount is controlled at 0.05-0.5 mm; the working mode of the cutting edge blade is obviously changed, and the working mode of the blade in the existing slitting process in Table 2 is compared:

[0034]

[0035]

[0036] Specifically, as shown in Figure 4 、 5 The disc cutter 5 is part of a cutting device in the slitting machine 1, the cutting device further comprises a cutter shaft 4 and a fixed steel frame 3, the fixed steel frame 3 is slidingly arranged on the transmission shaft 2 in the middle of the slitting machine 1, a clamping groove 31 is formed in the fixed steel frame 3, the cutter shaft 4 is fixed on the fixed steel frame 3 through thread cooperation of the clamping groove 31 and a fastening bolt, one end of the cutter shaft 4 is provided with a roller shaft, the disc cutter 5 is rotationally arranged on the roller shaft and abuts against the aluminum foil 6 from above, so as to realize cutting of the aluminum foil 6. In addition, the fixed steel frame 3 can realize adjustment of the cutting width of the aluminum foil 6 through the hand wheel 21 on the transmission shaft 2 and the linear transverse guide rail.

[0037] Because the aluminum foil used in power batteries has certain requirements for tensile strength and elongation, the battery foil products are all hard aluminum foils without annealing. The lubricant remaining at the cut edge needs to have the characteristic of rapid evaporation; otherwise, it will flow into the customer's coating performance. Therefore, this invention has made significant adjustments to the use of lubricant in the slitting process, using a highly volatile lubricant. This lubricant is made by mixing D40-D60 base oil (any one of base oils No. 40-60) with industrial alcohol in a 1:1 ratio. Compare the characteristics of the lubricant in the existing slitting process in Table 3:

[0038]

[0039] S3, Slitting: The rolled aluminum foil is inserted into the feeding roll and conveyed to the slitting machine at high speed under the control of tension and roller pressure, and abuts against the bottom of the disc cutter. The aluminum foil drives the disc cutter to rotate clockwise under the action of high speed. The speed of the disc cutter is synchronized with the slitting speed, which is controlled at 180-300m / min, thereby realizing the cutting of aluminum foil. The aluminum foil drives the disc cutter to rotate clockwise under the action of high speed, and the rotation is synchronized with the slitting speed to realize the cutting of aluminum foil. Uniform cutting maintains the consistency of the cut edge, which can reduce the generation of cut edge cracks and gaps, and greatly reduce the generation of burrs.

[0040] S4, during the slitting process in S3, the lubricant is intermittently dripped into the cutting edge to cool and lubricate the disc cutter;

[0041] S5, winding: The cut aluminum foil is wound onto the upper and lower take-up reels respectively.

[0042] In summary, compared with the original process technology, the present invention has optimized the following three aspects:

[0043] 1. Production process flow

[0044] like Figure 1 As shown, the original production process of aluminum foil for batteries is long. The finishing and equipment are limited by their own capabilities and can only cut the finished product into single strips, resulting in low production efficiency. Moreover, the longer the production process, the more unstable factors there are, which can easily lead to a low yield. In contrast, the present invention eliminates the finishing process and directly cuts the finished product into double strips on the slitting machine. By controlling the slitting speed, the production efficiency can be increased by 50% to 80%, which indirectly reduces the input of equipment, manpower and auxiliary materials, thereby reducing production costs.

[0045] 2. Slitting and precision cutting blades

[0046] The original battery aluminum foil is slit by using a Rutz blade / ceramic square blade, and only one blade corner is used in the process of slitting. The wear intensity of the blade is large, and the uneven heating or uneven heat dissipation is prone to occur, which can cause the defects of burr and wavy edge of the cut edge. The service life of the blade corner is short, and the blade corner needs to be frequently replaced, which affects the production efficiency. Or the disc cutter with a driving device is used to slit, which can improve the quality of the cut edge. Since it is not a completely active slitting, the improvement of the cut edge quality is limited, and it is difficult to control the burr within 50μm.

[0047] The disc cutter of tungsten steel material is used in the application, the disc cutter rotates synchronously with the slitting speed and is not limited by the change of the slitting speed, the lower cutter amount is controlled to be 0.05-0.5mm, the stable cut edge can be obtained, and the quality of the cut edge is improved.

[0048] 3. Slitting lubricant

[0049] The most commonly used lubricant for the original battery aluminum foil slitting cutter is two kinds, one is D80 / D90 base oil lubrication or rolling recovery oil, which has low oil film strength, high viscosity, good lubrication effect, good cut edge quality, and is suitable for slitting of the product after annealing process. Since the power battery aluminum foil does not undergo annealing, the oil film remaining on the cut edge of the aluminum foil is not easy to volatilize, and flows into the battery factory to coat the positive material, which is easy to cause leakage. Customers often complain; the second is industrial alcohol lubricating cutter, which has insufficient lubrication strength at high speed slitting, and is prone to cause burr and wavy edge defects.

[0050] The application adopts any one of D40-D60 base oil mixed with industrial alcohol 1:1 at a constant speed to drop into the cutter, the viscosity of the lubricant is between D90 and alcohol, and the volatilization is fast, which can ensure the product quality at high speed slitting, and can effectively reduce the generation of burr and wavy edge.

[0051] The slitting speed of the application can reach 180-300m / min, the burr is controlled within 50μm, and no wavy edge is generated at the edge. As shown in Figure 2 The cut edge end face diagram of the aluminum foil prepared by the application is shown in b, and it can be known that the cut edge of the aluminum foil after slitting is flat without wavy edge and edge lifting phenomenon; as shown in Figure 3As shown, a is an observation diagram of the aluminum foil for the production process of the original power battery aluminum foil under a microscope at 300 times magnification, b is an observation diagram of the aluminum foil prepared by the production process of the application under a microscope at 300 times magnification, and it can be seen from the diagram that the edge burr of the power battery aluminum foil obtained by the production process of the application is obviously improved, and the burr is completely controlled within 50 μm, while the burr of the power battery aluminum foil prepared by the original process is more than 50 μm.

[0052] The above description is only the preferred embodiment of the application, and is not a limitation on the design of the application. Any equivalent changes made according to the key design of the application fall within the scope of the application.

Claims

1. A production process for slitting of aluminum foil for high efficiency high quality lithium ion power batteries, characterized by: Comprise the following steps: S1, preparation: before the production of slitting, each guide roller system in the slitting machine is thoroughly cleaned, and whether each guide roller system is abnormal is checked, and the range of slitting tension and roll pressure control is adjusted; S2, adjusting the slitting precision cutter and the slitting lubricant: the slitting machine adopts the mode of double-width simultaneous slitting with middle strip drawing and two-side precision cutting edge, which adopts disc cutter blade, the disc cutter is made of tungsten steel, the lower knife amount is controlled at 0.05~0.5mm, and volatile lubricant is used, the lubricant is made by mixing base oil with industrial alcohol at a ratio of 1:1, and the base oil is any one of D40~D60 base oil; S3, slitting: the rolled aluminum foil is inserted into the feeding roll, and is conveyed to the slitting machine under the control of tension and roll pressure, and abuts below the disc cutter, the aluminum foil drives the disc cutter to rotate clockwise under the action of high-speed operation, the disc cutter rotating speed is synchronous with the slitting speed, and the speed is controlled at 180~300m / min, so as to realize cutting the aluminum foil; S4, in the slitting process of S3, the lubricant is intermittently dropped into the knife gap to cool and lubricate the disc cutter; S5, winding: the cut aluminum foil is wound on the upper and lower winding shafts respectively; The disc cutter in S2 is part of the cutting device in the slitting machine, the cutting device further comprises a cutter shaft and a fixed steel frame, the fixed steel frame is slidingly arranged on the transmission shaft in the middle of the slitting machine, a clamping groove is formed in the fixed steel frame, the cutter shaft is fixed on the fixed steel frame through the clamping groove and the threaded cooperation of the fastening bolt, one end of the cutter shaft is provided with a roller shaft, and the disc cutter is rotatably arranged on the roller shaft and abuts against the upper side of the aluminum foil; The clamping groove is in arc structure, and the distance between the two ends of the clamping groove and the aluminum foil is different.

2. The process for slitting production of aluminum foil for high efficiency and high quality lithium-ion power battery as claimed in claim 1, characterized in that: The fixed steel frame realizes the adjustment of the cutting width of the aluminum foil through the hand wheel on the transmission shaft and the linear transverse guide rail.

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