A method for improving the surface zeta potential of a battery foil

Abstract

The application provides a method for improving the surface daoyin value of a battery foil, belongs to the technical field of new energy batteries, and comprises the following steps: performing secondary rolling on an aluminum foil for a battery to obtain secondary rolling, wherein the secondary rolling comprises rough rolling and finish rolling in sequence; and the rolling oil used in the rolling comprises the following components: base oil, alcohol, ester and daoyin liquid, wherein the daoyin liquid comprises formamide, ethylene glycol ethyl ether and modified polyacrylamide; and the modified polyacrylamide is 2-acrylamide-2-methylpropane sulfonic acid modified polyacrylamide. Through the method for improving the surface daoyin value of the battery foil by means of secondary rolling and by reasonably adding suitable additives, the surface wetting tension of the battery foil is improved, and then the surface performance of the battery is improved, so that the method has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of new energy battery technology, and specifically to a method for increasing the dyne value of battery foil surface. Background Technology

[0002] Lithium-ion batteries are a key component for the power output of new energy vehicles. Aluminum foil, as the positive electrode material, significantly impacts the lifespan, consistency, and rate discharge performance of lithium-ion batteries. Currently, high-end lithium-ion battery aluminum foil requires high dimensional accuracy, a clean and uniform surface, and freedom from scratches and other defects. With the continuous development of the new energy vehicle industry, the thickness of high-end lithium-ion battery aluminum foil is constantly decreasing, while the requirements for tensile strength and elongation are increasing. To ensure discharge performance and elongation, existing lithium-ion battery aluminum foil raw materials often use alloys with an aluminum content of over 99%. To improve the tensile strength of the finished lithium-ion battery aluminum foil, a second cold-rolled billet recrystallization annealing process is performed to ensure that the tensile strength of the foil raw material is ≥185 N / mm². 2 In order to achieve a final tensile strength of ≥250 N / mm² 2 Technical requirements.

[0003] Currently, the publicly disclosed production process for aluminum foil used in ordinary lithium batteries involves the following steps: aluminum foil for lithium batteries is heated and melted into an aluminum alloy melt according to a certain alloy composition ratio; the aluminum alloy melt, after processes such as slag removal, grain refinement, degassing, slag removal and filtration, is continuously cast and rolled into a billet using a casting and rolling mill; the billet is then cold-rolled, recrystallized and annealed, and then cold-rolled and finished to obtain a billet for lithium battery aluminum foil; the billet is then rough-rolled, fine-rolled and slit by a roller mill to obtain the finished aluminum foil for lithium batteries.

[0004] With the continuous development of new energy vehicles, the battery industry using aluminum foil as the current collector has flourished. Battery foil has also become a high value-added product in the aluminum processing industry. As an important indicator affecting the coating of battery materials, the dyne value of battery foil surface is currently a problem. The vast majority of aluminum foil manufacturers at home and abroad have low product quality due to dyne value issues, and have been unable to enter the high-end power battery foil market, which has affected the development of high-end batteries. Summary of the Invention

[0005] The purpose of this invention is to propose a method for improving the dyne value of battery foil surface. By using a secondary rolling process and adding appropriate additives, the dyne value of the battery foil surface is increased, thereby improving the wetting tension of the battery foil surface and thus improving the surface performance of the battery. This method has broad application prospects.

[0006] The technical solution of this invention is implemented as follows:

[0007] This invention provides a method for improving the dyne value of battery foil surface. The battery foil is subjected to secondary rolling, which includes rough rolling and fine rolling in sequence. The rolling oil used for rolling has the following components: base oil, alcohol, ester, and dyne solution. The dyne solution includes formamide, ethylene glycol ethyl ether, and modified polyacrylamide. The modified polyacrylamide is 2-acrylamide-2-methylpropanesulfonic acid modified polyacrylamide.

[0008] As a further improvement of the present invention, the rolling oil for rolling is prepared from the following raw materials in parts by weight: 30-40 parts base oil, 5-7 parts alcohol, 3-6 parts ester, and 20-40 parts dyne solution.

[0009] As a further improvement of the present invention, the rolling oil for rolling is prepared from the following raw materials in parts by weight: 35 parts base oil, 6 parts alcohol, 5 parts ester, and 30 parts dyne solution.

[0010] As a further improvement of the present invention, the mass ratio of formamide, ethylene glycol ethyl ether and modified polyacrylamide in the dyne solution is 3-5:10-12:5-7.

[0011] As a further improvement of the present invention, the modified polyacrylamide is prepared as follows: acrylamide and 2-acrylamide-2-methylpropanesulfonic acid are prepared into monomer aqueous solutions with contents of 40-50wt% and 15-20wt% respectively. The pH value is adjusted, and stabilizer, emulsifier, white oil and initiator are added. Under inert gas protection, the mixture is stirred and reacted. Hexane is added, filtered, washed and dried to obtain modified polyacrylamide.

[0012] As a further improvement of the present invention, the pH value is adjusted to 6.9-7.1; the stabilizer is EDTA or disodium EDTA; the emulsifier includes Span-80 and Tween-80 in a mass ratio of 3-5:3; the initiator is selected from at least one of sodium persulfate, ammonium persulfate, and potassium persulfate; and the mass ratio of the stabilizer, emulsifier, white oil, and initiator is 1-2:2-4:40-50:0.1-0.3.

[0013] As a further improvement of the present invention, the base oil is 82# base oil.

[0014] As a further improvement of the present invention, the alcohol includes hexadecyl alcohol and octadecyl alcohol in a mass ratio of 3-5:2, and the ester includes methyl octadecyl acetate and ethyl hexadecyl acetate in a mass ratio of 2-4:1.

[0015] As a further improvement of the present invention, the surface roughness of the finishing roll is 0.06-0.09 μm, and the rolling temperature is 45-55℃.

[0016] As a further improvement of the present invention, the roughing roll has a surface roughness of 0.09-0.11 μm and a rolling temperature of 40-50℃.

[0017] The present invention has the following beneficial effects: The present invention prepares a modified polyacrylamide by introducing 2-acrylamide-2-methylpropanesulfonic acid into the molecular chain of polyacrylamide, which not only improves the surface properties of polyacrylamide, but also introduces anionic surfactant, thereby greatly reducing surface tension and improving wettability with water, thereby improving the wetting tension of the battery foil surface and thus greatly improving the dyne value of the battery foil surface.

[0018] This invention improves the dyne value of the battery foil surface by using a secondary rolling process and adding appropriate additives, thereby increasing the wetting tension of the battery foil surface and improving the surface performance of the battery, which has broad application prospects. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1

[0021] This embodiment provides a method for improving the dyne value of battery foil surface, which involves secondary rolling of battery aluminum foil, including rough rolling and fine rolling.

[0022] The roughing roll has a surface roughness of 0.09 μm and a rolling temperature of 40 °C.

[0023] The finishing mill rolls have a surface roughness of 0.06 μm and a rolling temperature of 45 °C.

[0024] The rolling oil is prepared from the following raw materials in parts by weight: 30 parts of 82# base oil, 5 parts of alcohol, 3 parts of ester, and 20 parts of dyne solution. The alcohol includes hexadecyl alcohol and octadecyl alcohol in a mass ratio of 3:2, and the ester includes methyl octadecyl acetate and ethyl hexadecyl acetate in a mass ratio of 2:1.

[0025] The dyne solution comprises formamide, ethylene glycol ethyl ether, and modified polyacrylamide in a mass ratio of 3:10:5.

[0026] The modified polyacrylamide is prepared as follows: 100 parts by weight of acrylamide and 2-acrylamide-2-methylpropanesulfonic acid are prepared into monomer aqueous solutions with contents of 40 wt% and 15 wt%, respectively. The pH value is adjusted to 6.9. 1 part by weight of EDTA, 2 parts by weight of emulsifier, 40 parts by weight of white oil and 0.1 parts by weight of sodium persulfate are added. Under nitrogen protection, the mixture is stirred and reacted for 3 hours. An equal volume of n-hexane is added. The mixture is filtered, washed, and dried to obtain the modified polyacrylamide.

[0027] The emulsifiers include Span-80 and Tween-80 in a mass ratio of 3:3.

[0028] Example 2

[0029] This embodiment provides a method for improving the dyne value of battery foil surface, which involves secondary rolling of battery aluminum foil, including rough rolling and fine rolling.

[0030] The roughing roll has a surface roughness of 0.11 μm and a rolling temperature of 50 °C.

[0031] The finishing mill rolls have a surface roughness of 0.09 μm and a rolling temperature of 55°C.

[0032] The rolling oil is prepared from the following raw materials in parts by weight: 40 parts of 82# base oil, 7 parts of alcohol, 6 parts of ester, and 40 parts of dyne solution. The alcohol includes hexadecyl alcohol and octadecyl alcohol in a mass ratio of 5:2, and the ester includes methyl octadecyl acetate and ethyl hexadecyl acetate in a mass ratio of 4:1.

[0033] The dyne solution comprises formamide, ethylene glycol ethyl ether, and modified polyacrylamide in a mass ratio of 5:12:7.

[0034] The modified polyacrylamide is prepared as follows: 100 parts by weight of acrylamide and 2-acrylamide-2-methylpropanesulfonic acid are prepared into monomer aqueous solutions with contents of 50 wt% and 20 wt%, respectively. The pH value is adjusted to 7.1. 2 parts by weight of EDTA, 4 parts by weight of emulsifier, 50 parts by weight of white oil and 0.3 parts by weight of ammonium persulfate are added. Under nitrogen protection, the mixture is stirred and reacted for 5 h. An equal volume of n-hexane is added, and the mixture is filtered, washed, and dried to obtain the modified polyacrylamide.

[0035] The emulsifiers include Span-80 and Tween-80 in a mass ratio of 5:3.

[0036] Example 3

[0037] This embodiment provides a method for improving the dyne value of battery foil surface, which involves secondary rolling of battery aluminum foil, including rough rolling and fine rolling.

[0038] The roughing roll has a surface roughness of 0.1 μm and a rolling temperature of 45 °C.

[0039] The finishing mill rolls have a surface roughness of 0.07 μm and a rolling temperature of 50 °C.

[0040] The rolling oil is prepared from the following raw materials in parts by weight: 35 parts of 82# base oil, 6 parts of alcohol, 5 parts of ester, and 30 parts of dyne solution. The alcohol includes hexadecyl alcohol and octadecyl alcohol in a mass ratio of 4:2, and the ester includes methyl octadecyl acetate and ethyl hexadecyl acetate in a mass ratio of 3:1.

[0041] The dyne solution comprises formamide, ethylene glycol ethyl ether, and modified polyacrylamide in a mass ratio of 4:11:6.

[0042] The modified polyacrylamide is prepared as follows: 100 parts by weight of acrylamide and 2-acrylamide-2-methylpropanesulfonic acid are prepared into monomer aqueous solutions with contents of 45 wt% and 17 wt%, respectively. The pH value is adjusted to 7. 1.5 parts by weight of disodium EDTA, 3 parts by weight of emulsifier, 45 parts by weight of white oil and 0.2 parts by weight of potassium persulfate are added. Under nitrogen protection, the mixture is stirred and reacted for 3-5 hours. An equal volume of n-hexane is added, and the mixture is filtered, washed, and dried to obtain the modified polyacrylamide.

[0043] The emulsifiers include Span-80 and Tween-80 in a mass ratio of 4:3.

[0044] Example 4

[0045] The difference from Example 3 is that the alcohol is a single cetyl alcohol.

[0046] Specifically as follows:

[0047] The rolling oil is prepared from the following raw materials in parts by weight: 35 parts of 82# base oil, 6 parts of alcohol, 5 parts of ester, and 30 parts of dyne solution. The alcohol is hexadecyl alcohol, and the ester includes methyl octadecyl acetate and ethyl hexadecyl acetate in a mass ratio of 3:1.

[0048] Example 5

[0049] The difference from Example 3 is that the alcohol is a single octadecyl alcohol.

[0050] Specifically as follows:

[0051] The rolling oil is prepared from the following raw materials in parts by weight: 35 parts of 82# base oil, 6 parts of alcohol, 5 parts of ester, and 30 parts of dyne solution. The alcohol is octadecyl alcohol, and the ester includes methyl octadecyl acetate and ethyl hexadecyl acetate in a mass ratio of 3:1.

[0052] Example 6

[0053] The difference from Example 3 is that the ester is a single methyl octadecanoate.

[0054] Specifically as follows:

[0055] The rolling oil is prepared from the following raw materials in parts by weight: 35 parts of 82# base oil, 6 parts of alcohol, 5 parts of ester, and 30 parts of dyne solution. The alcohol includes cetyl alcohol and octadecyl alcohol in a mass ratio of 4:2, and the ester is methyl octadecyl ester.

[0056] Example 7

[0057] The difference from Example 3 is that the ester is a single ethyl hexadecanoate.

[0058] Specifically as follows:

[0059] The rolling oil is prepared from the following raw materials in parts by weight: 35 parts of 82# base oil, 6 parts of alcohol, 5 parts of ester, and 30 parts of dyne solution. The alcohol includes hexadecyl alcohol and octadecyl alcohol in a mass ratio of 4:2, and the ester is ethyl hexadecyl acetate.

[0060] Comparative Example 1

[0061] The difference from Example 3 is that the modified polyacrylamide was replaced by an equal amount of polyacrylamide.

[0062] Specifically as follows:

[0063] The dyne solution comprises formamide, ethylene glycol ethyl ether, and polyacrylamide in a mass ratio of 4:11:6.

[0064] Comparative Example 2

[0065] The difference from Example 3 is that the modified polyacrylamide was replaced by an equal amount of poly-2-acrylamide-2-methylpropanesulfonic acid.

[0066] Specifically as follows:

[0067] The dyne solution comprises formamide, ethylene glycol ethyl ether, and poly-2-acrylamide-2-methylpropanesulfonic acid in a mass ratio of 4:11:6.

[0068] Comparative Example 3

[0069] The difference from Example 3 is that the modified polyacrylamide was replaced by an equal amount of formamide.

[0070] Specifically as follows:

[0071] The dyne solution comprises formamide and ethylene glycol ethyl ether in a mass ratio of 10:11:6.

[0072] Comparative Example 4

[0073] The difference compared to Example 3 is that no alcohol was added.

[0074] Specifically as follows:

[0075] The rolling oil is prepared from the following raw materials in parts by weight: 35 parts of 82# base oil, 11 parts of ester, and 30 parts of dyne solution. The ester includes methyl octadecanoate and ethyl hexadecanoate in a mass ratio of 3:1.

[0076] Comparative Example 5

[0077] The difference compared to Example 3 is that no ester was added.

[0078] Specifically as follows:

[0079] The rolling oil is prepared from the following raw materials in parts by weight: 35 parts of 82# base oil, 11 parts of alcohol, 5 parts of ester, and 30 parts of dyne solution. The alcohol includes cetyl alcohol and octadecyl alcohol in a mass ratio of 4:2.

[0080] Test Example 1

[0081] The contact angles of the battery foils prepared in Examples 1-7 and Comparative Examples 1-5 were tested, and the results are shown in Table 1.

[0082] Table 1

[0083] Group Water contact angle (°) Example 1 99 Example 2 101 Example 3 102 Example 4 90 Example 5 92 Example 6 87 Example 7 85 Comparative Example 1 76 Comparative Example 2 70 Comparative Example 3 67 Comparative Example 4 78 Comparative Example 5 72

[0084] As can be seen from the table above, the battery foils prepared in Examples 1-3 of the present invention have good wettability.

[0085] Test Example 2

[0086] The battery foils prepared in Examples 1-7 and Comparative Examples 1-5 were placed in an 80°C oven for 5 minutes (simulating the temperature during rolling to reduce the amount of oil on the surface). Finally, the surface wetting tension of the samples was measured using No. 30 and No. 32 dyne pens, and the results are shown in Table 2.

[0087] Table 2

[0088] Group No. 30 Dain Pen No. 32 Dain Pen Example 1 No shrinkage No shrinkage Example 2 No shrinkage No shrinkage Example 3 No shrinkage No shrinkage Example 4 No shrinkage Slow contraction after 10 seconds Example 5 No shrinkage Slow contraction after 15 seconds Example 6 No shrinkage slow contraction Example 7 No shrinkage slow contraction Comparative Example 1 No shrinkage shrink Comparative Example 2 slow contraction shrink Comparative Example 3 shrink shrink Comparative Example 4 Slow contraction after 1 minute shrink Comparative Example 5 Slow contraction after 70 seconds shrink

[0089] As can be seen from the table above, the battery foils prepared in Examples 1-3 of the present invention have high dyne values.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for increasing the dyne value of a battery foil surface, characterized in that, The battery is subjected to a second rolling process using aluminum foil. The second rolling process includes rough rolling and finish rolling. The rolling oil used in the second rolling process is prepared from the following raw materials in parts by weight: 30-40 parts base oil, 5-7 parts alcohol, 3-6 parts ester, and 20-40 parts dyne solution. The dyne solution includes formamide, ethylene glycol ethyl ether, and modified polyacrylamide. The modified polyacrylamide is 2-acrylamide-2-methylpropanesulfonic acid modified polyacrylamide.

2. The method for increasing the dyne value of battery foil surface according to claim 1, characterized in that, The rolling oil for secondary rolling is prepared from the following raw materials in parts by weight: 35 parts base oil, 6 parts alcohol, 5 parts ester, and 30 parts dyne solution.

3. The method for increasing the dyne value of battery foil surface according to claim 1, characterized in that, The mass ratio of formamide, ethylene glycol ethyl ether, and modified polyacrylamide in the dyne solution is 3-5:10-12:5-7.

4. The method for increasing the dyne value of battery foil surface according to claim 3, characterized in that, The modified polyacrylamide is prepared as follows: Acrylamide and 2-acrylamide-2-methylpropanesulfonic acid are prepared into monomer aqueous solutions with contents of 40-50wt% and 15-20wt%, respectively. The pH value is adjusted, and stabilizer, emulsifier, white oil and initiator are added. Under inert gas protection, the mixture is stirred and reacted. Hexane is added, filtered, washed and dried to obtain modified polyacrylamide.

5. The method for increasing the dyne value of battery foil surface according to claim 4, characterized in that, The pH value is adjusted to 6.9-7.1; the stabilizer is EDTA or disodium EDTA; the emulsifier includes Span-80 and Tween-80 in a mass ratio of 3-5:3; the initiator is selected from at least one of sodium persulfate, ammonium persulfate, and potassium persulfate; and the mass ratio of the stabilizer, emulsifier, white oil, and initiator is 1-2:2-4:40-50:0.1-0.

3.

6. The method for increasing the dyne value of battery foil surface according to claim 1, characterized in that, The base oil is 82# base oil.

7. The method for increasing the dyne value of battery foil surface according to claim 1, characterized in that, The alcohol includes hexadecyl alcohol and octadecyl alcohol in a mass ratio of 3-5:2, and the ester includes methyl octadecanoate and ethyl hexadecanoate in a mass ratio of 2-4:

1.

8. The method for increasing the dyne value of battery foil surface according to claim 1, characterized in that, The finishing mill rolls have a surface roughness of 0.06-0.09 μm and a rolling temperature of 45-55℃.

9. The method for increasing the dyne value of battery foil surface according to claim 1, characterized in that, The roughing roll has a surface roughness of 0.09-0.11 μm and a rolling temperature of 40-50℃.