Battery foil and method for manufacturing the same, battery, and electric device

Abstract

The application relates to a battery foil and a preparation method thereof, a battery and a power utilization device. The preparation method of the battery foil comprises the following steps: rough rolling treatment, medium rolling treatment and fine rolling treatment of a battery foil blank by using rolling oil in sequence; the rolling oil comprises base oil and rolling additives, the oil film strength alpha of the rolling oil is greater than 280 N, and the friction coefficient mu of the oil film is less than 0.05; the temperature of the rough rolling treatment is T1, the temperature of the medium rolling treatment is T2, and the temperature of the fine rolling treatment is T3, T1 < T2 < T3; the processing rate of the rough rolling treatment is S1, the processing rate of the medium rolling treatment is S2, and the processing rate of the fine rolling treatment is S3, S1 > S2 > S3; the rolling speed of the rough rolling treatment is V1, the rolling speed of the medium rolling treatment is V2, and the rolling speed of the fine rolling treatment is V3, V1 > V2 > V3. The preparation method of the battery foil can effectively improve the adhesion of the battery foil.

Description

Technical Field

[0001] This application relates to the field of batteries, and in particular to a battery foil and its preparation method, as well as batteries and electrical devices. Background Technology

[0002] With the development of new energy vehicles, the demand for batteries such as lithium-ion batteries has grown rapidly. Lithium-ion batteries include lithium nickel cobalt manganese oxide (LCO) power batteries and lithium iron phosphate (LFP) power batteries. For example, the positive electrode of a LCO power battery includes a current collector and a positive electrode active layer containing LCO material on the surface of the current collector; the positive electrode of a LFP power battery includes a current collector and a positive electrode active layer containing LFP material on the surface of the current collector. The adhesion between the positive electrode active layer and the current collector affects the battery's stability and cycle life. Battery aluminum foil is a commonly used positive electrode current collector material; however, battery aluminum foil produced by traditional methods has relatively low adhesion. Summary of the Invention

[0003] Based on this, this application provides a method for preparing a battery foil with high adhesion, as well as a battery foil, a battery, and an electrical device.

[0004] The technical solution to the above-mentioned technical problems in this application is as follows.

[0005] This application provides a method for preparing battery foil, comprising the following steps:

[0006] The battery foil blank is subjected to rough rolling, intermediate rolling and finish rolling in sequence using rolling oil;

[0007] The rolling oil includes base oil and rolling additives, and the oil film strength α > 280N and the friction coefficient μ < 0.05.

[0008] The temperature for the rough rolling process is T1, the temperature for the intermediate rolling process is T2, and the temperature for the finish rolling process is T3, where T1 < T2 < T3;

[0009] The processing rate of the rough rolling process is S1, the processing rate of the intermediate rolling process is S2, and the processing rate of the finish rolling process is S3, where S1 > S2 > S3;

[0010] The rolling speed for the roughing process is V1, the rolling speed for the intermediate rolling process is V2, and the rolling speed for the finishing process is V3, where V1 < V2 < V3.

[0011] In some embodiments, the testing standards for the oil film strength and friction coefficient in the battery foil preparation method are in accordance with GB / T12583.

[0012] In some embodiments, in the method for preparing battery foil, the rolling additive in the rolling oil has a mass percentage content of 5.5% to 7%.

[0013] In some embodiments, in the method for preparing battery foil, the temperature of the rough rolling process is 38°C to 42°C, the temperature of the intermediate rolling process is 43°C to 47°C, and the temperature of the finish rolling process is 48°C to 52°C.

[0014] In some embodiments, in the method for preparing battery foil, the rough rolling process has a processing rate of 45% to 55%, the intermediate rolling process has a processing rate of 45% to 50%, and the finish rolling process has a processing rate of 40% to 45%.

[0015] In some embodiments, in the method for preparing the battery foil, the rolling speed of the rough rolling process is 400 m / min to 500 m / min, the rolling speed of the intermediate rolling process is 450 m / min to 550 m / min, and the rolling speed of the finish rolling process is 500 m / min to 600 m / min.

[0016] In some embodiments, in the method for preparing battery foil, the rolling oil used in the rough rolling process and the intermediate rolling process is a first rolling oil, and the rolling oil used in the finish rolling process is a second rolling oil. The first rolling oil includes the base oil, the rolling additive, and lauric acid, and the acid value of the first rolling oil is <0.25 mgKOH / g; the second rolling oil is composed of the base oil and the rolling additive.

[0017] In some embodiments, in the method for preparing battery foil, the crown of the work rolls in the roughing, intermediate, and finishing processes is independently 0.02 mm to 0.05 mm.

[0018] In some embodiments, the method for preparing battery foil further includes a step of corona degreasing the battery foil material obtained by the fine rolling process after the fine rolling process is completed.

[0019] In some embodiments, in the method for preparing battery foil, the battery foil blank is a battery aluminum foil blank, and the battery foil is a battery aluminum foil.

[0020] The second aspect of this application provides a battery foil, which is prepared using the battery foil preparation method provided in the first aspect of this application.

[0021] A third aspect of this application provides a battery, including the battery foil provided in the second aspect of this application.

[0022] The fourth aspect of this application provides an electrical device, including the battery provided in the third aspect of this application.

[0023] Compared with the prior art, the method for preparing battery foil in this application has the following advantages:

[0024] The above-mentioned method for preparing battery foil involves sequentially performing rough rolling, intermediate rolling, and finish rolling on the battery foil blank using rolling oil. By controlling the oil film strength and friction coefficient of the rolling oil, the amount of rolling additives added to the rolling oil can be controlled. Furthermore, the temperatures of the rough rolling, intermediate rolling, and finish rolling processes are sequentially controlled to increase, the processing rate is sequentially controlled to decrease, and the rolling speed is sequentially controlled to increase. The interaction between these four factors can effectively improve the adhesion of the battery foil. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 SEM image of the battery aluminum foil product obtained in Example 1;

[0027] Figure 2 This is a SEM image of the battery aluminum foil product prepared in Comparative Example 1. Detailed Implementation

[0028] Reference will now be made to detailed embodiments of the present invention, one or more of which are described below. Each example is provided for explanation and not for limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from its scope or spirit. For example, features described or illustrated as part of one embodiment may be used in another embodiment to produce further embodiments.

[0029] Therefore, this invention is intended to cover such modifications and variations falling within the scope of the appended claims and their equivalents. Other objects, features, and aspects of the invention are disclosed in or will be apparent from the following detailed description. It will be understood by those skilled in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of the invention.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0031] The terms “comprising,” “including,” or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element preceded by the phrase “comprising one…” does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The indefinite articles “a” and “an” preceding an element or component of the invention are not restrictive in terms of the number of elements or components (i.e., the number of times they appear). Therefore, “an” or “an” should be interpreted as including one or at least one, and singular elements or components also include plural forms, unless the quantity clearly refers only to the singular. “A plurality” means at least two, such as two, three, etc., unless otherwise expressly specified.

[0032] The weights of the relevant components mentioned in the embodiments of this invention can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this invention is within the scope disclosed in the embodiments of this invention. Specifically, the weights mentioned in the embodiments of this invention can be well-known units of mass in the chemical industry, such as μg, mg, g, and kg.

[0033] Unless otherwise shown or indicated in the operational embodiments, all figures used to represent the amounts, physicochemical properties, etc., of ingredients in the specification and claims are to be understood to be adjusted by the term "about" in all cases. For example, therefore, unless stated to the contrary, the numerical parameters listed in the foregoing specification and appended claims are approximations, and those skilled in the art can appropriately modify these approximations to obtain the desired characteristics by utilizing the teachings disclosed herein. The use of numerical ranges indicated by endpoints includes all numbers within that range and any range within that range; for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, etc.

[0034] One embodiment of this application provides a method for preparing battery foil, comprising the following steps:

[0035] The battery foil blank is subjected to rough rolling, intermediate rolling and finish rolling in sequence using rolling oil;

[0036] The rolling oil includes base oil and rolling additives. The oil film strength α of the rolling oil is greater than 280N and the friction coefficient μ is less than 0.05.

[0037] The temperature for rough rolling is T1, the temperature for intermediate rolling is T2, and the temperature for finish rolling is T3, where T1 < T2 < T3;

[0038] The processing rate for rough rolling is S1, the processing rate for intermediate rolling is S2, and the processing rate for finish rolling is S3, where S1 > S2 > S3.

[0039] The rolling speed for roughing is V1, the rolling speed for intermediate rolling is V2, and the rolling speed for finishing rolling is V3, where V1 > V2 > V3.

[0040] The suppliers of rolling additives used for rolling battery foil vary in the market, and the effective content and composition of the rolling additives also differ. In this case, directly determining the content of the rolling additive and rolling the battery foil based on this may result in problems such as low load-bearing capacity, high coefficient of friction, and high residue, leading to low adhesion of the produced battery aluminum foil and thus a low pass rate. Furthermore, the problem of low adhesion caused by the content of rolling additives cannot be solved by corona degreasing.

[0041] For battery aluminum foil that is thinned by the speed effect, the foil rolling characteristics dominated by fluid lubrication determine the smooth surface properties of the battery aluminum foil. Under these surface properties, abnormal plate shape or surface abnormalities (reduced oil level) will lead to a decrease in the adhesion between the aluminum foil and the coating material.

[0042] The method for preparing battery foil in this application involves sequentially performing rough rolling, intermediate rolling, and finish rolling on the battery foil blank using rolling oil. By controlling the oil film strength and friction coefficient of the rolling oil, the amount of rolling additives added to the rolling oil can be controlled. Furthermore, the temperatures of the rough rolling, intermediate rolling, and finish rolling processes are sequentially controlled to increase, the processing rate is sequentially controlled to decrease, and the rolling speed is sequentially controlled to increase. The interaction between these four factors can effectively improve the adhesion of the battery foil.

[0043] The principle of controlling the temperature of roughing, intermediate rolling, and finishing rolling in sequence from low to high is as follows: During roughing and intermediate rolling of battery foil billets, due to the large absolute reduction, the lubrication state is in a mixed lubrication state, or a state transitioning from mixed lubrication to fluid lubrication. Controlling the roughing and intermediate rolling processes at a lower temperature can improve the oil film strength, reduce the friction coefficient, reduce aluminum powder formation, and stabilize the thermal crown of the rolls, thereby achieving plate shape stability. During finishing rolling (finished product pass rolling), the requirements for oil film strength are reduced under fluid lubrication. Controlling the finishing rolling process at a higher temperature can effectively control the amount of oil carried, especially the amount of rolling additives attached.

[0044] It is understood that this application does not limit the type of base oil and the type of rolling additives, as long as they can be used to roll battery foils and the oil film formed therefrom can meet the requirements of oil film strength > 280N and friction coefficient < 0.05.

[0045] In some of these examples, the base oil used in the preparation of the battery foil includes at least one of No. 80 base oil and No. 85 base oil.

[0046] It is understandable that the ortho-structure content of No. 80 base oil and No. 85 base oil is ≥10%.

[0047] In some of these examples, the rolling additives in the preparation method of the battery foil include at least one of an alcohol and an ester, wherein the C-chain length of the alcohol and the ester is greater than the C-chain length of the base oil.

[0048] It is understandable that the molecular weight of the alcohol or ester in the rolling additive is independently greater than the C-chain length of the base oil.

[0049] The non-seize load PB(N) is the non-seize load that prevents the test steel ball from seizing under test conditions. It represents the oil film strength.

[0050] In some of these examples, the rolling oil has a film strength α > 290 N and a friction coefficient μ < 0.04 in the battery foil preparation method.

[0051] In some of these examples, the preparation method of the battery foil uses a four-ball testing machine to test the oil film strength and friction coefficient.

[0052] In some of these examples, the testing standards for the oil film strength and friction coefficient of the battery foil are in accordance with GB / T12583.

[0053] In some of these examples, the battery foil preparation method uses battery aluminum foil blanks as the battery foil blanks. Accordingly, this example provides a method for preparing battery aluminum foil.

[0054] In some of these examples, the rolling additives are present at a mass percentage of 5.5% to 7% in the battery foil preparation method.

[0055] It is understood that the mass percentage content of rolling additives includes, but is not limited to, 5.5%, 5.8%, 6%, 6.2%, 6.5%, 6.8%, and 7%.

[0056] It is understandable that, based on the premise that the oil film strength of the rolling oil is >280N and the friction coefficient is <0.05, the selection of the mass percentage content of the rolling additive can be comprehensively measured by considering the mass percentage content of the rolling additive, the oil film strength, and the friction coefficient.

[0057] In some examples, the rolling oil used in the roughing and intermediate rolling processes of the battery foil is the first rolling oil. Based on the requirement that the oil film strength is >280N and the friction coefficient is <0.05, the mass percentage of rolling additives in the first rolling oil is selected to be at a lower proportion.

[0058] Furthermore, based on the conditions that the oil film strength is >280N and the coefficient of friction is <0.05, and given that the mass percentage content of rolling additives is relatively similar, the mass percentage content of rolling additives in the first rolling oil is selected to be higher than that of the oil film strength.

[0059] In some of these examples, the rolling oil used in the finishing rolling process is a second rolling oil. Based on the conditions that the oil film strength is >280N and the coefficient of friction is <0.05, the second rolling oil is selected with a lower mass percentage of rolling additives.

[0060] Furthermore, based on the conditions that the oil film strength is >280N and the coefficient of friction is <0.05, and given that the mass percentage content of rolling additives is relatively similar, the mass percentage content of rolling additives in the second rolling oil is selected to be lower than the coefficient of friction.

[0061] In some examples, in the method for preparing battery foil, the first rolling oil includes a base oil, rolling additives and a polarizing agent, and the acid value of the first rolling oil is <0.25 mgKOH / g; the second rolling oil is composed of base oil and rolling additives.

[0062] Furthermore, polar agents include lauric acid.

[0063] That is, the first rolling oil includes base oil, rolling additives and lauric acid.

[0064] By controlling the rolling oil used in roughing and intermediate rolling processes to include polar agents such as lauric acid, while the rolling oil used in finishing rolling processes does not include polar agents such as lauric acid, and by limiting the acid value of the first rolling oil, the influence of the rolling oil on the adhesion of the battery foil surface can be further reduced.

[0065] It is understandable that the temperatures of roughing, intermediate rolling, and finishing processes are controlled by controlling the temperature of the rolling oil.

[0066] In some of these examples, the battery foil preparation method involves a rough rolling temperature of 38°C to 42°C, a medium rolling temperature of 43°C to 47°C, and a finish rolling temperature of 48°C to 52°C.

[0067] It is understood that the temperatures for rough rolling include, but are not limited to, 38℃, 39℃, 40℃, 41℃, and 42℃; the temperatures for intermediate rolling are 43℃, 44℃, 45℃, 46℃, and 47℃; and the temperatures for finish rolling are 48℃, 49℃, 50℃, 51℃, and 52℃. In some examples, any two of these point values ​​can be used as endpoints within a range, and the same applies below.

[0068] It is understandable that by controlling the processing rates of roughing, intermediate rolling and finishing rolling "from high to low", while ensuring that the formation of aluminum powder in the roughing and intermediate rolling passes is minimized, and while achieving flatness of the plate shape in each pass, the content of non-volatile oily substances such as rolling additives is reduced as much as possible, thus providing a good degreasing foundation for the corona degreasing process in the finishing rolling step.

[0069] In some of these examples, the processing rate of the battery foil preparation method is 45% to 55% for rough rolling, 45% to 50% for intermediate rolling, and 40% to 45% for finish rolling.

[0070] It is understood that the processing rates for rough rolling include, but are not limited to, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, and 55%, the processing rates for intermediate rolling include, but are not limited to, 45%, 46%, 47%, 48%, 49%, and 50%, and the processing rates for finish rolling include, but are not limited to, 40%, 41%, 42%, 43%, 44%, and 45%.

[0071] In some of these examples, the rolling speed for roughing is 400 m / min to 500 m / min, the rolling speed for intermediate rolling is 450 m / min to 550 m / min, and the rolling speed for finishing rolling is 500 m / min to 600 m / min.

[0072] In some examples, the rolling speeds for roughing the battery foil are 400 m / min, 410 m / min, 420 m / min, 430 m / min, 440 m / min, 450 m / min, 460 m / min, 470 m / min, 480 m / min, 490 m / min, and 500 m / min; the rolling speeds for intermediate rolling are 450 m / min, 460 m / min, 470 m / min, 480 m / min, 490 m / min, 500 m / min, 510 m / min, 520 m / min, 530 m / min, 540 m / min, and 550 m / min; and the rolling speeds for finishing rolling are 500 m / min, 510 m / min, 520 m / min, 530 m / min, 540 m / min, 550 m / min, 560 m / min, 570 m / min, and 580 m / min. m / min, 590 m / min, 600 m / min.

[0073] In some of these examples, the crown of the work rolls in the roughing, intermediate, and finishing processes of the battery foil preparation method is independently 0.02 mm to 0.05 mm.

[0074] It is understood that the crown of the work rolls in roughing, intermediate rolling and finishing processes are independently, but not limited to, 0.02 mm, 0.03 mm, 0.04 mm and 0.05 mm respectively.

[0075] The aforementioned method for preparing battery foil is particularly suitable for rolling battery aluminum foil using wide aluminum foil rolling mills of 1850mm and above, including but not limited to 1850mm and 2150mm aluminum foil rolling mills. This process ensures the flatness of the foil while achieving high cleanliness and specific surface characteristics. This type of aluminum foil not only meets the performance requirements of current collectors for ternary lithium-ion batteries but also satisfies the higher quality requirements of lithium iron phosphate batteries for high adhesion of current collectors, and is applicable to most energy storage battery manufacturing fields.

[0076] In some of these examples, the thickness of the battery foil blank is 0.22 mm to 0.35 mm in the battery foil preparation method.

[0077] In some of these examples, the battery foil preparation method has a tensile strength > 140 MPa for the battery foil blank.

[0078] In some of these examples, the convexity of the battery foil blank is 0.1% to 0.6%, and the thickness difference is <1.0%.

[0079] In some of these examples, in the battery foil preparation method, for the 1850mm series battery foil rolling mill, the width of the battery foil blank is ≤1550mm.

[0080] In some of these examples, in the battery foil preparation method, for a 2150mm series battery foil rolling mill, the width of the battery foil blank is <1900mm.

[0081] In some of these examples, the method for preparing the battery foil also includes the following steps:

[0082] The battery foil material after precision rolling is degreased by corona discharge.

[0083] Furthermore, during corona degreasing, the principle is to aim for the appearance of slight discharge pits.

[0084] In some of these examples, in step S30, the rate of corona degreasing is 80 m / min to 160 m / min.

[0085] It is understood that the speed of corona degreasing includes, but is not limited to, 80 m / min, 90 m / min, 100 m / min, 110 m / min, 120 m / min, 130 m / min, 140 m / min, 150 m / min, and 160 m / min.

[0086] In some of these examples, a step of precision cutting the precision-rolled battery foil material is included before corona degreasing.

[0087] The above-mentioned method for preparing battery foil significantly improves adhesion, especially the stability of the plate shape and consistency of adhesion. While greatly reducing the residue of rolling additives or polar agents (lauric acid) on the surface of the battery foil, it also causes nanoscale electrolytic pits to appear on the surface of the battery foil, resulting in a wide battery foil with high flatness and adhesion. This method can meet the surface and plate shape requirements of high-adhesion battery foils for both ternary and lithium iron phosphate systems.

[0088] One embodiment of this application provides a battery foil, which is prepared using the battery foil preparation method described above.

[0089] One embodiment of this application provides a battery including the aforementioned battery foil.

[0090] Furthermore, the battery includes lithium-ion batteries.

[0091] Furthermore, the batteries include lithium nickel cobalt manganese oxide batteries and lithium iron phosphate batteries.

[0092] In some of these examples, the battery includes a positive electrode, a separator, and a negative electrode. The positive electrode includes a current collector and a positive electrode active layer on the surface of the current collector. The current collector includes the aforementioned battery foil.

[0093] It is understandable that the positive electrode active layer has a high adhesion to the aforementioned battery foil, resulting in better stability and cycle life.

[0094] In some examples, the current collector may be made of the aforementioned battery foil, i.e., the current collector may be directly prepared using the aforementioned aluminum battery foil. In other examples, the current collector may be made of other materials in addition to the aforementioned battery foil.

[0095] One embodiment of this application provides an electrical device including the battery described above.

[0096] It is understood that electrical devices include, but are not limited to, automobiles, airplanes, medical equipment, and household appliances.

[0097] The present application will be described in further detail below with reference to specific embodiments, but the embodiments of the present application are not limited thereto.

[0098] The base oil used in the following examples and comparative examples is No. 80 base oil (Shijiazhuang Xintai Special Oil Co., Ltd. D80X model) that has undergone high-pressure hydrogenation treatment and has a n-hydrocarbon content of about 15%.

[0099] Rolling oils A, B, C, and D were prepared using No. 80 base oil, lauric acid, and rolling additive (MARK625W3-H model from Shijiazhuang Xintai Special Oil Co., Ltd.), with rolling additive mass percentages of 5%, 6%, 7%, and 8%, respectively, and an acid value of 0.25 mgKOH / g. Rolling oils E, F, G, and H were also prepared using No. 80 base oil and rolling additive (MARK625W3-H model from Shijiazhuang Xintai Special Oil Co., Ltd.), with rolling additive mass percentages of 5%, 6%, 7%, and 8%, respectively. The oil film strength and tribological properties of the oil films containing different mass percentages of rolling additive were tested using a four-ball testing machine according to GB / T12583. The results are shown in Table 1.

[0100] Table 1

[0101]

[0102] As shown in Table 1, for rolling oils A to D, when the mass percentage of rolling additives is 6%, the oil film strength is >280N and the friction coefficient is <0.05, indicating relatively high strength. However, when the mass percentage of rolling additives exceeds 7%, the oil film strength does not increase, but the friction coefficient does.

[0103] Example 1

[0104] The aluminum foil blank was rough rolled using rolling oil B. The temperature of the rolling oil was 40℃, the processing rate was 50%, and the rolling speed was 450 m / min.

[0105] The aluminum foil after rough rolling was subjected to intermediate rolling using rolling oil B. During the intermediate rolling process, the temperature of the rolling oil was 45℃, the processing rate was 48%, and the rolling speed was 500 m / min.

[0106] The aluminum foil material after intermediate rolling was subjected to fine rolling using rolling oil F. During the fine rolling process, the temperature of the rolling oil was 50℃, the processing rate was 43%, and the rolling speed was 550 m / min.

[0107] The crown of the work rolls in the roughing, intermediate, and finishing processes is 0.03 mm.

[0108] The precision-rolled aluminum foil is then precision-cut and subjected to corona treatment for degreasing. The corona power is set to 60%–75% of the main machine power (corona discharge power corresponding to the corona roller), and the corona speed is set to 80–160 m / min. The corona speed is adjusted based on a dyne value ≥34 after 8 hours of corona treatment. The final SEM image of the finished battery aluminum foil is obtained, as shown below. Figure 1 As shown, the images include SEM images at 1000x (X1000) and 2000x (X2000) magnification, respectively, before and after Plasma (corona removal) treatment, at one and two times.

[0109] from Figure 1 It can be seen that the finished battery aluminum foil product obtained in Example 1 has electrical pits.

[0110] Example 2

[0111] The process is basically the same as in Example 1, except that rolling oil C is used to perform rough rolling and intermediate rolling on the aluminum foil after rough rolling, and rolling oil G is used to perform finish rolling on the aluminum foil after intermediate rolling.

[0112] Example 3

[0113] The process is basically the same as in Example 1, except that in the rough rolling process, the rolling oil temperature is 38°C, the processing rate is 55%, and the rolling speed is 400 m / min; in the intermediate rolling process, the rolling oil temperature is 47°C, the processing rate is 45%, and the rolling speed is 450 m / min; and in the finish rolling process, the rolling oil temperature is 52°C, the processing rate is 40%, and the rolling speed is 600 m / min.

[0114] Comparative Example 1

[0115] The aluminum foil blank was subjected to rough rolling, intermediate rolling and finish rolling in sequence using rolling oil D. The rolling oil D in the rough rolling, intermediate rolling and finish rolling processes was 50℃, the processing rate was 50%, the rolling speed was 550 m / min, and the crown of the work roll was 0.03 mm.

[0116] The precision-rolled aluminum foil is then precision-cut and subjected to corona treatment for degreasing. The corona power is set to 60%–75% of the main machine power (corona discharge power corresponding to the corona roller), and the corona speed is set to 80–160 m / min. The corona speed is adjusted based on a dyne value ≥34 after 8 hours of corona treatment. The final SEM image of the finished battery aluminum foil is obtained, as shown below. Figure 2 As shown.

[0117] from Figure 2 It can be seen that the finished battery aluminum foil obtained in Comparative Example 1 is relatively smooth.

[0118] Comparative Example 2

[0119] The process is basically the same as in Example 1, except that rolling oil A is used to perform rough rolling and intermediate rolling on the aluminum foil after rough rolling, and rolling oil E is used to perform finish rolling on the aluminum foil after intermediate rolling.

[0120] Comparative Example 3

[0121] The process is basically the same as in Example 1, except that the temperature of the rolling oil is set to 52°C in the roughing process, 45°C in the intermediate rolling process, and 42°C in the finishing process.

[0122] Comparative Example 4

[0123] The process is basically the same as in Example 1, except that the processing rate is 50% in the rough rolling process, 48% in the intermediate rolling process, and 48% in the finish rolling process.

[0124] Comparative Example 5

[0125] The process is basically the same as in Example 1, except that the rolling speed is 550 m / min in the roughing process, 500 m / min in the intermediate rolling process, and 450 m / min in the finishing process.

[0126] The adhesion of the battery aluminum foil products prepared in each embodiment and comparative example was tested according to GB / T33143-2016. Based on the actual test results for each three months after the technology was implemented and stabilized, and referring to the peel strength statistics for the three months before the technology was put into use, the peel strength of the finished products was tested and the pass rate was calculated. The statistical results are shown in Table 2.

[0127] Table 2

[0128]

[0129] As can be seen from Table 2, by controlling the content of additives by controlling the oil film strength and friction, and by taking the processing rate "from large to small" and the rolling speed and rolling oil temperature "from low to high" in combination with process design and control, the adhesion of battery aluminum foil is stabilized and the pass rate is significantly improved.

[0130] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0131] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for preparing battery foil, characterized in that, Includes the following steps: The battery foil blank is subjected to rough rolling, intermediate rolling and finish rolling in sequence using rolling oil; The rolling oil includes base oil and rolling additives, and the oil film strength α > 280 N and the friction coefficient μ < 0.

05. The temperature for rough rolling is T1, the temperature for intermediate rolling is T2, and the temperature for finish rolling is T3, where T1 < T2 < T3; the temperature for rough rolling is 38℃~42℃, the temperature for intermediate rolling is 43℃~47℃, and the temperature for finish rolling is 48℃~52℃. The processing rate of the rough rolling process is S1, the processing rate of the intermediate rolling process is S2, and the processing rate of the finish rolling process is S3, where S1 > S2 > S3; The rolling speed for the roughing process is V1, the rolling speed for the intermediate rolling process is V2, and the rolling speed for the finishing process is V3, where V1 < V2 < V3.

2. The preparation method according to claim 1, characterized in that, The testing standards for the oil film strength and the coefficient of friction are in accordance with GB / T12583.

3. The preparation method according to claim 1, characterized in that, The preparation method includes at least one of the following features: (1) The rolling additive in the rolling oil has a mass percentage content of 5.5% to 7.5%; (2) The roughing process has a processing rate of 45% to 55%, the intermediate rolling process has a processing rate of 45% to 50%, and the finishing process has a processing rate of 40% to 45%. (3) The rolling speed of the roughing process is 400 m / min ~ 500 m / min, the rolling speed of the intermediate rolling process is 450 m / min ~ 550 m / min, and the rolling speed of the finishing process is 500 m / min ~ 600 m / min.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The rolling oil used in the roughing and intermediate rolling processes is a first rolling oil, and the rolling oil used in the finishing rolling process is a second rolling oil. The first rolling oil includes the base oil, the rolling additive, and lauric acid, and the acid value of the first rolling oil is <0.25 mgKOH / g. The second rolling oil is composed of the base oil and the rolling additive.

5. The preparation method according to any one of claims 1 to 3, characterized in that, The crown of the work rolls in the roughing, intermediate, and finishing processes is independently 0.02 mm to 0.05 mm.

6. The preparation method according to any one of claims 1 to 3, characterized in that, After the finishing rolling process is completed, the process also includes a step of corona degreasing the battery foil material obtained by the finishing rolling process.

7. The preparation method according to any one of claims 1 to 3, characterized in that, The battery foil blank is a battery aluminum foil blank, and the battery foil is a battery aluminum foil.

8. A battery foil, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 7.

9. A battery, characterized in that, Includes the battery foil as described in claim 8.

10. An electrical device, characterized in that, Includes the battery as described in claim 9.

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