Aluminum alloy strip for battery shell production and preparation method of aluminum alloy strip

Abstract

The invention discloses an aluminum alloy strip for battery case production and a preparation method thereof, and relates to the technical field of aluminum alloy processing, and the aluminum alloy strip comprises the following components in parts by weight: 75-95 parts of aluminum, 2-4 parts of silicon, 0.35-0.55 part of magnesium, 0.3-0.5 part of manganese, 1.30-1.80 parts of copper, 0.30-0.70 part of zinc, 0.20-0.50 part of titanium, 0.20-0.45 part of strontium, 0.35-0.65 part of rare earth elements and inevitable impurity elements. According to the aluminum alloy strip for producing the battery shell and the preparation method of the aluminum alloy strip, the components of the aluminum alloy are reasonably adjusted, so that the components of the aluminum alloy are more reasonable, and the produced aluminum alloy strip has the characteristics of high strength, high heat dissipation speed and corrosion resistance, can meet the use requirements of a lithium battery, and is good in use effect and high in practicability. Good use prospects are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy processing, and in particular to an aluminum alloy strip for battery shell production and a preparation method thereof. Background Art

[0002] The battery shell is the external protective structure of the battery, which is used to wrap and fix the components inside the battery, providing physical protection, isolation, heat dissipation and other functions. The normal battery shell is made of aluminum alloy.

[0003] Aluminum alloy strip is a strip product made of aluminum and other alloy elements. The main metal element is aluminum, and some alloy elements are added to improve the performance of aluminum.

[0004] With the progress of society, the application of lithium batteries is becoming more and more common. People are paying more and more attention to lithium batteries and the aluminum alloy materials used in lithium batteries.

[0005] The existing patent application publication number is CN106811628B, and the patent name is a method for producing aluminum strips for power battery shells by a casting and rolling method. The invention patent discloses a method that can improve the tensile strength of aluminum foil. The specific steps are: proportioning raw materials according to the composition of the alloy; adding additives to adjust the composition after the raw materials are melted; introducing the raw materials into a static furnace after smelting; casting and rolling the treated aluminum liquid after online degassing and filtration; performing two metamorphic treatments in the flow channel between the degassing box and the static furnace, and in the flow channel between the filter box and the casting and rolling machine; the produced cast-rolled slabs are welded with inner and outer rings after a certain rolling, and annealed at a thickness of 4.0-9.0mm; the aluminum coils of the finished thickness are subjected to secondary heat treatment, and then slitting and processing, and slitting to the target width. The method of the present invention is different from the traditional hot rolling method, and adopts the casting and rolling method to achieve cost savings and shorten the cycle.

[0006] The strength of the alloy produced above is not high and cannot meet the requirements of battery safety protection. In addition, the stress of the produced aluminum alloy strip is relatively large and requires further processing before it can be used for production. The overall process is relatively complicated, and the high stress increases the risks of storage and transportation, which does not meet people's use requirements. For this reason, we propose an aluminum alloy strip for battery shell production and a preparation method thereof. Summary of the invention

[0007] The main purpose of the present invention is to provide an aluminum alloy strip for battery shell production and a preparation method thereof, which can effectively solve the problems in the background technology.

[0008] To achieve the above object, the technical solution adopted by the present invention is:

[0009] An aluminum alloy strip for battery shell production includes the following components in parts by weight: 75-95 parts of aluminum, 2-4 parts of silicon, 0.35-0.55 parts of magnesium, 0.3-0.5 parts of manganese, 1.30-1.80 parts of copper, 0.30-0.70 parts of zinc, 0.20-0.50 parts of titanium, 0.20-0.45 parts of strontium, 0.35-0.65 parts of rare earth elements and unavoidable impurity elements.

[0010] An aluminum alloy strip for battery shell production includes the following components in parts by weight: 80 parts of aluminum, 3 parts of silicon, 0.45 parts of magnesium, 0.4 parts of manganese, 1.60 parts of copper, 0.50 parts of zinc, 0.35 parts of titanium, 0.35 parts of strontium, 0.50 parts of rare earth elements and unavoidable impurity elements.

[0011] Preferably, the rare earth element comprises a mixture of erbium and gadolinium, and the weight ratio of erbium to gadolinium in the mixture of erbium and gadolinium is 6:8.

[0012] An aluminum alloy strip for battery shell production and a preparation method thereof, comprising the following steps:

[0013] S1. Raw material processing: weigh the raw materials and send them into a powder mixer for uniform mixing;

[0014] S2, raw material smelting: adding the uniformly mixed raw materials to the smelting equipment for smelting;

[0015] S3, extrusion molding; conveying the smelted raw materials to a rolling mill and rolling them into a strip;

[0016] S4, solution treatment: cooling and solution aging treatment of the strip aluminum alloy;

[0017] S5. Size adjustment: cutting and trimming the aluminum alloy after solution treatment to a fixed length;

[0018] S6. Oxidation treatment: performing oxidation treatment on the cut and trimmed aluminum alloy strip;

[0019] S7. Evaluation feedback: Measure the properties of the aluminum alloy strip, make a comprehensive evaluation of the measurement results, and implement corresponding strategies based on the results of the comprehensive evaluation.

[0020] Preferably, the steps of smelting raw materials in step S2 are as follows:

[0021] S21, furnace chamber preheating: the temperature in the vacuum melting furnace is raised to 560-580°C, and kept at this temperature for 10-20 minutes, and then lowered to room temperature;

[0022] S22. Alloy smelting: Add the raw materials into the vacuum melting furnace, raise the temperature in the vacuum melting furnace to 800-830℃, the temperature rise rate is 40-60℃ / s, stir the melting device for 1min every 8-10min, and the speed of stirring is 30-40r / min:

[0023] S23, refining treatment: add refining agent into the vacuum melting furnace for refining for 15-20 minutes, then remove slag and impurities to remove slag in the melt.

[0024] Preferably, nitrogen is used for degassing after slag removal and impurity removal, and the nitrogen degassing time is 15-20 minutes.

[0025] Preferably, the steps of cooling solution aging treatment in step S4 are as follows:

[0026] S41, heating the strip aluminum alloy to 590-610°C for primary solution treatment for 1.5-2h;

[0027] S42, lowering the temperature of the strip aluminum alloy after the initial solution treatment to 520-550° C. for pre-precipitation for 0.5-0.8 h;

[0028] S43, heating the strip aluminum alloy after the pre-precipitation treatment to 590-610° C. for secondary solution treatment for 1.5-2 h;

[0029] S44, cooling the strip aluminum alloy after the secondary solution treatment to room temperature in a water bath for 1-2 hours and then cooling to -150--170°C for deep cryogenic treatment;

[0030] S44. After deep cryogenic treatment, the strip aluminum alloy is restored to room temperature for 0.5-1h and then placed in an oil bath for 10-12h at a temperature of 180-200°C.

[0031] Preferably, before the oxidation treatment in step S6, the strip aluminum alloy is firstly subjected to acid washing and alkali washing, and then the strip aluminum alloy is immersed in an electrolytic cell containing sulfuric acid and copper sulfate as an anode, and electricity is applied to perform the oxidation treatment.

[0032] Preferably, when measuring the properties of the aluminum alloy strip in S7, the maximum grain size, the average grain size and the residual stress of a partial area of ​​the aluminum alloy strip are randomly extracted.

[0033] Preferably, the comprehensive evaluation value of the aluminum alloy strip is as follows:

[0034]

[0035] Where Z is the comprehensive evaluation value of aluminum alloy strip, LJ pj is the average grain size of aluminum alloy strip, LJ bzis the average grain size in the aluminum alloy strip, LJ zd is the maximum grain size of aluminum alloy strip, YL JC In order to detect the residual stress of aluminum alloy strip, YL BJ is the residual stress of the aluminum alloy strip, A, B and C are weight coefficients, A+B+C=100;

[0036] When Z < 60, the production plan of aluminum alloy is reformulated;

[0037] When 60≤Z≤90, the control variable method is used to adjust the parameters in the production process of aluminum alloy;

[0038] When Z>90, there is no need to adjust the production process of the aluminum alloy.

[0039] Compared with the prior art, the aluminum alloy strip for battery shell production and the preparation method thereof of the present invention have the following beneficial effects:

[0040] First, the present invention records an aluminum alloy strip for battery shell production and a preparation method thereof, which reasonably adjusts the composition of the aluminum alloy to make the composition of the aluminum alloy more reasonable. The produced aluminum alloy strip has the characteristics of high strength, fast heat dissipation and corrosion resistance, can meet the use requirements of lithium batteries, has good use effect, and has good use prospects.

[0041] Second, the present invention records an aluminum alloy strip for battery shell production and its preparation method, which mainly strengthens the solid solution treatment effect. First, the gadolinium component is increased to improve the supersaturation of the alloy matrix. At the same time, in the pre-precipitation and aging treatment stages, the precipitated phase in the alloy can be more evenly dispersed, and a large amount of rare earth-rich second phase will be formed, which effectively improves the mechanical properties of the alloy, which is conducive to improving the stress corrosion resistance of the alloy. In addition, the cooling solid solution aging treatment method is used to improve the supercooling of the alloy and reduce the distance between the dendrites of the cast grains. Moreover, when rare earth elements are dissolved in the α-Al matrix, the lattice will be distorted and dislocations will be formed. When the dislocations inside the alloy are high, the grain boundaries of the alloy will become rough, which will promote the formation of small grains in the alloy, so that the grains are refined, and the hydrogen content in the alloy is reduced, the probability of internal defects in the material is reduced, and the service life is increased. It also further reduces the content of impurities in the alloy, so that the alloy has a good use effect, and at the same time greatly reduces the stress of the aluminum alloy strip, which is convenient for subsequent processing and has a good use prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The present invention is a flow chart of a method for preparing an aluminum alloy strip for battery shell production. DETAILED DESCRIPTION

[0043] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0044] Example 1

[0045] An aluminum alloy strip for battery shell production includes the following components in parts by weight: 75 parts of aluminum, 2 parts of silicon, 0.38 parts of magnesium, 0.35 parts of manganese, 1.45 parts of copper, 0.40 parts of zinc, 0.30 parts of titanium, 0.25 parts of strontium, 0.40 parts of rare earth elements and unavoidable impurity elements.

[0046] The rare earth element comprises a mixture of erbium and gadolinium, wherein the weight ratio of erbium to gadolinium in the mixture is 6:8.

[0047] A method for preparing an aluminum alloy strip for battery shell production comprises the following steps:

[0048] S1. Raw material processing: weigh the raw materials and send them into a powder mixer for uniform mixing;

[0049] S2, raw material smelting: adding the uniformly mixed raw materials to the smelting equipment for smelting;

[0050] The steps of raw material smelting are as follows;

[0051] S21, furnace chamber preheating: the temperature in the vacuum melting furnace is raised to 570°C, and kept at this temperature for 16 minutes, and then lowered to room temperature;

[0052] S22. Alloy smelting: Add the raw materials into the vacuum melting furnace, raise the temperature in the vacuum melting furnace to 820°C, the temperature rise rate is 50°C / s, stir the melting device for 1 minute every 10 minutes, and the speed of stirring is 35r / min:

[0053] S23, refining treatment: adding a refining agent to a vacuum melting furnace for refining for 18 minutes, and then performing slag removal to remove slag in the melt. After slag removal, nitrogen is used for degassing, and the nitrogen degassing time is 18 minutes;

[0054] S3, extrusion molding; conveying the smelted raw materials to a rolling mill and rolling them into a strip;

[0055] S4, solution treatment: cooling and solution aging treatment of the strip aluminum alloy;

[0056] The steps of cooling solution aging treatment are as follows:

[0057] S41, heating the strip aluminum alloy to 600°C for a primary solution treatment for 1.5 hours;

[0058] S42, lowering the temperature of the strip aluminum alloy after the initial solution treatment to 530° C. for pre-precipitation for 0.6 h;

[0059] S43, heating the strip aluminum alloy after the pre-precipitation treatment to 600°C for secondary solution treatment for 1.5h;

[0060] S44, cooling the strip aluminum alloy after the secondary solution treatment to room temperature in a water bath for 1 hour and then cooling to -150°C for deep cryogenic treatment;

[0061] S44. After deep cryogenic treatment, the strip aluminum alloy is placed in an oil bath for 12 hours when the strip aluminum alloy returns to room temperature for 0.6 hours, and the temperature of the oil bath is 190°C;

[0062] S5. Size adjustment: cutting and trimming the aluminum alloy after solution treatment to a fixed length;

[0063] S6. Oxidation treatment: performing oxidation treatment on the cut and trimmed aluminum alloy strip;

[0064] Before oxidation treatment, the strip aluminum alloy is firstly pickled and alkali washed, and then the strip aluminum alloy is immersed in an electrolytic cell containing sulfuric acid and copper sulfate as an anode, and electricity is applied for oxidation treatment;

[0065] S7. Evaluation feedback: Measure the properties of the aluminum alloy strip, make a comprehensive evaluation of the measurement results, and implement corresponding strategies based on the results of the comprehensive evaluation.

[0066] When measuring the properties of the aluminum alloy strip, the maximum grain size, the average grain size and the residual stress of a portion of the aluminum alloy strip are randomly sampled.

[0067] The comprehensive evaluation values ​​of aluminum alloy strip are as follows:

[0068]

[0069] Where Z is the comprehensive evaluation value of aluminum alloy strip, LJ pj is the average grain size of aluminum alloy strip, LJ bz is the average grain size in the aluminum alloy strip, LJ zd is the maximum grain size of aluminum alloy strip, YL JC In order to detect the residual stress of aluminum alloy strip, YL BJ is the residual stress of the aluminum alloy strip, A, B and C are weight coefficients, A+B+C=100;

[0070] When Z is less than 60, the production plan of aluminum alloy is re-formulated, because the factory usually uses the previous aluminum alloy production process during production, so the products produced in the first few batches have major problems (usually a small amount is produced to correct the process);

[0071] When 60≤Z≤90, the control variable method is used to adjust the parameters in the aluminum alloy production process (this situation usually occurs in the middle of the process adjustment, when most of the data have been determined);

[0072] When Z>90, there is no need to adjust the production process of aluminum alloy. (This situation belongs to normal production and processing. Due to the interference of the external environment and the vibration of the equipment, there are certain errors, which can be corrected by normal maintenance).

[0073] Example 2

[0074] An aluminum alloy strip for battery shell production includes the following components in parts by weight: 95 parts of aluminum, 4 parts of silicon, 0.52 parts of magnesium, 0.45 parts of manganese, 1.70 parts of copper, 0.65 parts of zinc, 0.45 parts of titanium, 0.45 parts of strontium, 0.60 parts of rare earth elements and unavoidable impurity elements.

[0075] The rare earth element comprises a mixture of erbium and gadolinium, wherein the weight ratio of erbium to gadolinium in the mixture is 6:8.

[0076] A method for preparing an aluminum alloy strip for battery shell production comprises the following steps:

[0077] S1. Raw material processing: weigh the raw materials and send them into a powder mixer for uniform mixing;

[0078] S2, raw material smelting: adding the uniformly mixed raw materials to the smelting equipment for smelting;

[0079] The steps of raw material smelting are as follows;

[0080] S21, furnace chamber preheating: the temperature in the vacuum melting furnace is raised to 570°C, and kept at this temperature for 16 minutes, and then lowered to room temperature;

[0081] S22. Alloy smelting: Add the raw materials into the vacuum melting furnace, raise the temperature in the vacuum melting furnace to 820°C, the temperature rise rate is 50°C / s, stir the melting device for 1 minute every 10 minutes, and the speed of stirring is 35r / min:

[0082] S23, refining treatment: adding a refining agent to a vacuum melting furnace for refining for 18 minutes, and then performing slag removal to remove slag in the melt. After slag removal, nitrogen is used for degassing, and the nitrogen degassing time is 18 minutes;

[0083] S3, extrusion molding; conveying the smelted raw materials to a rolling mill and rolling them into a strip;

[0084] S4, solution treatment: cooling and solution aging treatment of the strip aluminum alloy;

[0085] The steps of cooling solution aging treatment are as follows:

[0086] S41, heating the strip aluminum alloy to 600°C for a primary solution treatment for 1.8h;

[0087] S42, lowering the temperature of the strip aluminum alloy after the initial solution treatment to 540°C for pre-precipitation for 0.6h;

[0088] S43, heating the strip aluminum alloy after the pre-precipitation treatment to 600°C for secondary solution treatment for 1.8h;

[0089] S44, cooling the strip aluminum alloy after the secondary solution treatment to room temperature in a water bath for 1.6 hours and then cooling to -160°C for deep cryogenic treatment;

[0090] S44. After deep cryogenic treatment, the strip aluminum alloy is placed in an oil bath for 12 hours when the strip aluminum alloy returns to room temperature for 0.8 hours, and the temperature of the oil bath is 190°C;

[0091] S5. Size adjustment: cutting and trimming the aluminum alloy after solution treatment to a fixed length;

[0092] S6. Oxidation treatment: performing oxidation treatment on the cut and trimmed aluminum alloy strip;

[0093] Before oxidation treatment, the strip aluminum alloy is firstly pickled and alkali washed, and then the strip aluminum alloy is immersed in an electrolytic cell containing sulfuric acid and copper sulfate as an anode, and electricity is applied for oxidation treatment;

[0094] S7. Evaluation feedback: Measure the properties of the aluminum alloy strip, make a comprehensive evaluation of the measurement results, and implement corresponding strategies based on the results of the comprehensive evaluation.

[0095] When measuring the properties of the aluminum alloy strip, the maximum grain size, the average grain size and the residual stress of a portion of the aluminum alloy strip are randomly sampled.

[0096] The comprehensive evaluation values ​​of aluminum alloy strip are as follows:

[0097]

[0098] Where Z is the comprehensive evaluation value of aluminum alloy strip, LJ pj is the average grain size of aluminum alloy strip, LJ bz is the average grain size in the aluminum alloy strip, LJ zd is the maximum grain size of aluminum alloy strip, YL JC In order to detect the residual stress of aluminum alloy strip, YL BJis the residual stress of the aluminum alloy strip, A, B and C are weight coefficients, A+B+C=100;

[0099] When Z is less than 60, the production plan of aluminum alloy is re-formulated, because the factory usually uses the previous aluminum alloy production process during production, so the products produced in the first few batches have major problems (usually a small amount is produced to correct the process);

[0100] When 60≤Z≤90, the control variable method is used to adjust the parameters in the aluminum alloy production process (this situation usually occurs in the middle of the process adjustment, when most of the data have been determined);

[0101] When Z>90, there is no need to adjust the production process of aluminum alloy. (This situation belongs to normal production and processing. Due to the interference of the external environment and the vibration of the equipment, there are certain errors, which can be corrected by normal maintenance).

[0102] Example 3

[0103] An aluminum alloy strip for battery shell production includes the following components in parts by weight: 80 parts of aluminum, 3 parts of silicon, 0.45 parts of magnesium, 0.4 parts of manganese, 1.60 parts of copper, 0.50 parts of zinc, 0.35 parts of titanium, 0.35 parts of strontium, 0.50 parts of rare earth elements and unavoidable impurity elements.

[0104] The rare earth element comprises a mixture of erbium and gadolinium, wherein the weight ratio of erbium to gadolinium in the mixture is 6:8.

[0105] A method for preparing an aluminum alloy strip for battery shell production comprises the following steps:

[0106] S1. Raw material processing: weigh the raw materials and send them into a powder mixer for uniform mixing;

[0107] S2, raw material smelting: adding the uniformly mixed raw materials to the smelting equipment for smelting;

[0108] The steps of raw material smelting are as follows;

[0109] S21, furnace chamber preheating: the temperature in the vacuum melting furnace is raised to 570°C, and kept at this temperature for 16 minutes, and then lowered to room temperature;

[0110] S22. Alloy smelting: Add the raw materials into the vacuum melting furnace, raise the temperature in the vacuum melting furnace to 820°C, the temperature rise rate is 50°C / s, stir the melting device for 1 minute every 10 minutes, and the speed of stirring is 35r / min:

[0111] S23, refining treatment: adding a refining agent to a vacuum melting furnace for refining for 18 minutes, and then performing slag removal to remove slag in the melt. After slag removal, nitrogen is used for degassing, and the nitrogen degassing time is 18 minutes;

[0112] S3, extrusion molding; conveying the smelted raw materials to a rolling mill and rolling them into a strip;

[0113] S4, solution treatment: cooling and solution aging treatment of the strip aluminum alloy;

[0114] The steps of cooling solution aging treatment are as follows:

[0115] S41, heating the strip aluminum alloy to 610°C for a primary solution treatment for 2 hours;

[0116] S42, lowering the temperature of the strip aluminum alloy after the initial solution treatment to 540°C for pre-precipitation for 0.8h;

[0117] S43, heating the strip aluminum alloy after the pre-precipitation treatment to 610°C for secondary solution treatment for 2h;

[0118] S44, cooling the strip aluminum alloy after the secondary solution treatment to room temperature in a water bath for 1 hour and then cooling to -170°C for deep cryogenic treatment;

[0119] S44. After deep cryogenic treatment, the strip aluminum alloy is placed in an oil bath for 12 hours when the strip aluminum alloy returns to room temperature for 0.8 hours, and the temperature of the oil bath is 190°C;

[0120] S5. Size adjustment: cutting and trimming the aluminum alloy after solution treatment to a fixed length;

[0121] S6. Oxidation treatment: performing oxidation treatment on the cut and trimmed aluminum alloy strip;

[0122] Before oxidation treatment, the strip aluminum alloy is firstly pickled and alkali washed, and then the strip aluminum alloy is immersed in an electrolytic cell containing sulfuric acid and copper sulfate as an anode, and electricity is applied for oxidation treatment;

[0123] S7. Evaluation feedback: Measure the properties of the aluminum alloy strip, make a comprehensive evaluation of the measurement results, and implement corresponding strategies based on the results of the comprehensive evaluation.

[0124] When measuring the properties of the aluminum alloy strip, the maximum grain size, the average grain size and the residual stress of a portion of the aluminum alloy strip are randomly sampled.

[0125] The comprehensive evaluation values ​​of aluminum alloy strip are as follows:

[0126]

[0127] Where Z is the comprehensive evaluation value of aluminum alloy strip, LJ pj is the average grain size of aluminum alloy strip, LJ bz is the average grain size in the aluminum alloy strip, LJ zd is the maximum grain size of aluminum alloy strip, YL JC In order to detect the residual stress of aluminum alloy strip, YL BJ is the residual stress of the aluminum alloy strip, A, B and C are weight coefficients, A+B+C=100;

[0128] When Z is less than 60, the production plan of aluminum alloy is re-formulated, because the factory usually uses the previous aluminum alloy production process during production, so the products produced in the first few batches have major problems (usually a small amount is produced to correct the process);

[0129] When 60≤Z≤90, the control variable method is used to adjust the parameters in the aluminum alloy production process (this situation usually occurs in the middle of the process adjustment, when most of the data have been determined);

[0130] When Z>90, there is no need to adjust the production process of aluminum alloy. (This situation belongs to normal production and processing. Due to the interference of the external environment and the vibration of the equipment, there are certain errors, which can be corrected by normal maintenance).

[0131] The aluminum alloy strip produced by the solution recorded as patent number CN106811628B was used as a comparative example, and the performance of the products of Examples 1-3 and the comparative example products was measured. The test results are shown in the following table;

[0132] Example 1 Example 2 Example 3 Example Tensile strength(MPa) 312 321 325 122 Elongation(%) 12.14 11.95 11.26 40％ Particle size (μm) 12.66 11.82 13.15 18.62 Residual stress (MPa) 82 86 81 186

[0133] It can be seen from the data in the above table that the performance of the aluminum alloy described in the present invention is greatly improved, while the performance improvement of the aluminum alloy produced by Example 3 is small compared with that of Example 2. Considering the cost and process difficulty, the best solution is Example 2.

[0134] The present invention reasonably adjusts the composition of the aluminum alloy, making the composition of the aluminum alloy more reasonable. The produced aluminum alloy strip has the characteristics of high strength, fast heat dissipation and corrosion resistance, can meet the use requirements of lithium batteries, has good use effect, and has good use prospects.

[0135] The present invention records an aluminum alloy strip for battery shell production and its preparation method, which mainly strengthens the effect of solid solution treatment. First, the gadolinium component is increased to improve the supersaturation of the alloy matrix. At the same time, in the pre-precipitation and aging treatment stages, the precipitated phase in the alloy can be more evenly dispersed, and a large amount of rare earth-rich second phase can be formed, which effectively improves the mechanical properties of the alloy, which is beneficial to improving the stress corrosion resistance of the alloy. In addition, the cooling solid solution aging treatment method is used to improve the supercooling of the alloy and reduce the distance between the dendrites of the cast grains. Moreover, when rare earth elements are dissolved in the α-Al matrix, the lattice will be distorted and dislocations will be formed. When the dislocations inside the alloy are high, the grain boundaries of the alloy will become rough, which will promote the formation of small grains in the alloy, resulting in grain refinement. At the same time, the hydrogen content in the alloy is reduced, the probability of internal defects in the material is reduced, and the service life is increased. The content of impurities in the alloy is further reduced, which makes the alloy have a good use effect. At the same time, the stress of the aluminum alloy strip is greatly reduced, which is convenient for subsequent processing and has a good prospect for use.

[0136] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An aluminum alloy strip for battery shell production, characterized in that: The invention comprises the following components in parts by weight: 75-95 parts of aluminum, 2-4 parts of silicon, 0.35-0.55 parts of magnesium, 0.3-0.5 parts of manganese, 1.30-1.80 parts of copper, 0.30-0.70 parts of zinc, 0.20-0.50 parts of titanium, 0.20-0.45 parts of strontium, 0.35-0.65 parts of rare earth elements and unavoidable impurity elements.

2. The aluminum alloy strip for battery shell production according to claim 1, characterized in that: The invention comprises the following components in parts by weight: 80 parts of aluminum, 3 parts of silicon, 0.45 parts of magnesium, 0.4 parts of manganese, 1.60 parts of copper, 0.50 parts of zinc, 0.35 parts of titanium, 0.35 parts of strontium, 0.50 parts of rare earth elements and unavoidable impurity elements.

3. An aluminum alloy strip for battery shell production according to any one of claims 1-2, characterized in that: The rare earth element comprises a mixture of erbium and gadolinium, wherein the weight ratio of erbium to gadolinium in the mixture is 6:

8.

4. The method for preparing an aluminum alloy strip for battery shell production according to claim 3, characterized in that: The following steps are involved: S1. Raw material processing: weigh the raw materials and send them into a powder mixer for uniform mixing; S2, raw material smelting: adding the uniformly mixed raw materials to the smelting equipment for smelting; S3, extrusion molding; conveying the smelted raw materials to a rolling mill and rolling them into a strip; S4, solution treatment: cooling and solution aging treatment of the strip aluminum alloy; S5. Size adjustment: cutting and trimming the aluminum alloy after solution treatment to a fixed length; S6. Oxidation treatment: performing oxidation treatment on the cut and trimmed aluminum alloy strip; S7. Evaluation feedback: Measure the properties of the aluminum alloy strip, make a comprehensive evaluation of the measurement results, and implement corresponding strategies based on the results of the comprehensive evaluation.

5. The method for preparing an aluminum alloy strip for battery shell production according to claim 4, characterized in that: The steps of raw material smelting in step S2 are as follows: S21, furnace chamber preheating: the temperature in the vacuum melting furnace is raised to 560-580°C, and kept at this temperature for 10-20 minutes, and then lowered to room temperature; S22. Alloy smelting: Add the raw materials into the vacuum melting furnace, raise the temperature in the vacuum melting furnace to 800-830℃, the temperature rise rate is 40-60℃ / s, stir the melting device for 1min every 8-10min, and the speed of stirring is 30-40r / min: S23, refining treatment: add refining agent into the vacuum melting furnace for refining for 15-20 minutes, then remove slag and impurities to remove slag in the melt.

6. The method for preparing an aluminum alloy strip for battery shell production according to claim 5, characterized in that: After slag removal and impurity removal, nitrogen is used for degassing, and the nitrogen degassing time is 15-20 minutes.

7. The aluminum alloy strip for battery shell production and the preparation method thereof according to claim 6, characterized in that: The steps of cooling solution aging treatment in step S4 are as follows: S41, heating the strip aluminum alloy to 590-610°C for primary solution treatment for 1.5-2h; S42, lowering the temperature of the strip aluminum alloy after the initial solution treatment to 520-550° C. for pre-precipitation for 0.5-0.8 h; S43, heating the strip aluminum alloy after the pre-precipitation treatment to 590-610° C. for secondary solution treatment for 1.5-2 h; S44, cooling the strip aluminum alloy after the secondary solution treatment to room temperature in a water bath for 1-2 hours and then cooling to -150--170°C for deep cryogenic treatment; S44. After deep cryogenic treatment, the strip aluminum alloy is restored to room temperature for 0.5-1h and then placed in an oil bath for 10-12h at a temperature of 180-200°C.

8. The method for preparing an aluminum alloy strip for battery shell production according to claim 7, characterized in that: In step S6, the strip aluminum alloy is firstly pickled and alkaline washed before oxidation treatment, and then the strip aluminum alloy is immersed in an electrolytic cell containing sulfuric acid and copper sulfate as an anode, and electricity is applied to perform oxidation treatment.

9. The method for preparing an aluminum alloy strip for battery shell production according to claim 8, characterized in that: When measuring the properties of the aluminum alloy strip in S7, the maximum grain size, the average grain size and the residual stress of a part of the aluminum alloy strip are randomly sampled.

10. The method for preparing an aluminum alloy strip for battery shell production according to claim 9, characterized in that: The comprehensive evaluation values ​​of the aluminum alloy strip are as follows: Where Z is the comprehensive evaluation value of aluminum alloy strip, LJ pj is the average grain size of aluminum alloy strip, LJ bz is the average grain size in the aluminum alloy strip, LJ zd is the maximum grain size of aluminum alloy strip, YL JC In order to detect the residual stress of aluminum alloy strip, YL BJ is the residual stress of the aluminum alloy strip, A, B and C are weight coefficients, A+B+C=100; When Z < 60, the production plan of aluminum alloy is reformulated; When 60≤Z≤90, the control variable method is used to adjust the parameters in the production process of aluminum alloy; When Z>90, there is no need to adjust the production process of the aluminum alloy.

Images