A process for improving the production process of lithium-ion copper foil crepe

Abstract

The present invention discloses a process for improving the production process of lithium-ion battery copper foil crinkled gauze, which relates to the technical field of lithium-ion battery copper foil and comprises the following steps: S1, preparing electrolyte: mixing sulfuric acid and lead carbonate solution to form electrolyte, and heating and insulating the electrolyte; S2, preparing additives: preparing a grain refiner, a wetting agent, and a high-level leveling agent, and mixing and stirring the grain refiner, the wetting agent, and the high-level leveling agent in a certain proportion to form a mixed additive; S3, making a sheet in a Hull cell: adding the electrolyte and the mixed additive into a Hull cell, and making a sheet of the electrolyte in the Hull cell; S4, electroplating the lithium-ion battery copper foil; S5, finished product inspection; by adding a grain refiner, a wetting agent, and a high-level leveling agent to the electrolyte, the copper foil is uniform and consistent during the continuous production process of the copper foil, without color difference stripes. From the perspective of the microstructure, after adjusting the additive process, the overall grain size of the copper foil decreases, the foil surface is smoother, and the uniformity of the foil surface increases.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery copper foils, and particularly relates to a process for improving the production process of lithium battery copper foil crepe. Background Art

[0002] Copper foil is one of the key materials for producing lithium-ion batteries. The quality of the copper foil directly affects the manufacturing process and comprehensive performance of lithium-ion batteries. As shown in Figure 2 and Figure 4 , during the production process of copper foil, it is easy to have uneven electroplating, electroplating color difference stripes on the surface of the copper foil, and fine crepe on the surface of the copper foil;

[0003] As the negative electrode current collector, the copper foil will cause wrinkling during the coating process, affecting the production of the electrode sheet, or the thickness is inconsistent at the crepe position during the coating process, affecting the product quality of the electrode sheet. Summary of the Invention

[0004] In order to overcome the above technical problems, the purpose of the present invention is to provide a process for improving the production process of lithium battery copper foil crepe. By adding a grain refiner, a wetting agent and a high-level leveling agent to the electrolyte, the grain refiner adsorbs on the cathode surface to form a tight adsorption layer, or selectively adsorbs in the high current density area of the cathode, where it is reduced, blocking the discharge process of metal ions or the surface diffusion of metal adsorbed atoms, slowing down the cathode reaction rate, thereby making the grains fine. The wetting agent reduces the surface tension of the cathode, making the electrolyte deposit more uniformly on the cathode. The high-level leveling agent deposits on the cathode. The surface roughness of the cathode is inconsistent. During the deposition process, the grains continuously accumulate and grow. The high-level leveling agent inhibits the further increase of the grains, making the deposition flat, so that the copper foil is uniform and consistent during the continuous production process, without color difference stripes. From the microscopic structure, after adjusting the additive process, the overall grain size of the copper foil decreases, the foil surface is more flat, and the uniformity of the foil surface increases.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A process for improving the production process of lithium battery copper foil crepe, comprising the following steps:

[0007] S1. Prepare the electrolyte: Mix sulfuric acid and lead carbonate solution to make the electrolyte, and heat and keep the electrolyte warm;

[0008] S2. Prepare the additives: Prepare a grain refiner, a wetting agent, and a high-level leveling agent, and mix and stir the grain refiner, the wetting agent, and the high-level leveling agent in a certain ratio to form a mixed additive;

[0009] S3. Make a test piece in a Hull cell: Add the electrolyte and the mixed additive into the Hull cell, and make a test piece of the electrolyte in the Hull cell;

[0010] S4, Lithium - ion copper foil electroplating: Place the lithium - ion copper foil into the electrolyte in a Hull cell for electroplating. After electroplating, the lithium - ion copper foil is successively subjected to water washing, chromic anhydride passivation, and drying.

[0011] S5, Finished product inspection: Peel the dried lithium - ion copper foil from the cathode plate and detect the glossiness and tensile strength.

[0012] As a further scheme of the present invention: In S1, the concentration of sulfuric acid is 100 g / L - 110 g / L, the concentration of copper ions is 90 g / L - 95 g / L, the concentration of chloride ions is 20 mg / L - 30 mg / L, and the temperature of the electrolyte is 45 °C - 55 °C.

[0013] As a further scheme of the present invention: The grain refiner is made of sodium 3 - mercapto - 1 - propane sulfonate, sodium mercaptoimidazole propanesulfonate, or a mixture of the two in any proportion. The grain refiner adsorbs on the cathode surface to form a tight adsorption layer, or selectively adsorbs in the high - current - density area of the cathode, where it is reduced, blocking the discharge process of metal ions or the surface diffusion of metal adsorbed atoms, slowing down the cathode reaction rate, and thus making the grains fine.

[0014] As a further scheme of the present invention: The wetting agent is alkyl alcohol polyoxyethylene polyoxypropylene ether or alkylphenol polyoxyethylene polyoxypropylene ether. The wetting agent reduces the surface tension of the cathode, making the electrolyte deposit more uniformly on the cathode.

[0015] As a further scheme of the present invention: The high - level leveling agent is a nitrogen - containing amine compound. The high - level leveling agent deposits on the cathode. Since the surface roughness of the cathode is inconsistent, during the deposition process, grains continuously accumulate and grow. The high - level leveling agent inhibits the further growth of grains, making the deposition flat.

[0016] As a further scheme of the present invention: The electrolyte concentration of the grain refiner is 4 ppm - 5 ppm.

[0017] As a further scheme of the present invention: The electrolyte concentration of the wetting agent is 1 ppm - 1.5 ppm.

[0018] As a further scheme of the present invention: The electrolyte concentration of the high - level leveling agent is 10 ppm - 15 ppm.

[0019] Advantages of the present invention: By adding a grain refiner, a wetting agent, and a high-level leveling agent to the electrolyte, the grain refiner adsorbs on the cathode surface to form a tight adsorption layer, or selectively adsorbs in the high-current density area of the cathode, where it is reduced, blocking the discharge process of metal ions or the surface diffusion of metal adsorbed atoms, slowing down the cathode reaction rate, and thus making the grains fine. The wetting agent reduces the surface tension of the cathode, making the electrolyte deposition on the cathode more uniform. The high-level leveling agent deposits on the cathode, and the surface roughness of the cathode is inconsistent. During the deposition process, the grains continuously accumulate and grow, and the high-level leveling agent inhibits the further rise of the grains, making the deposition flat. Therefore, during the continuous production process of the copper foil, the copper foil is uniform, without color difference stripes. From the perspective of the micro-structure, after adjusting the additive process, the overall grain size of the copper foil decreases, the foil surface is more flat, and the uniformity of the foil surface increases. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below with reference to the accompanying drawings.

[0021] Figure 1 is the flowchart of the present invention;

[0022] Figure 2 is the 700-fold optical display diagram of the lithium-ion copper foil produced by the prior art;

[0023] Figure 3 is the 700-fold optical display diagram of the lithium-ion copper foil produced by the present invention;

[0024] Figure 4 is the 1050-fold optical display diagram of the lithium-ion copper foil produced by the prior art;

[0025] Figure 5 is the 1050-fold optical display diagram of the lithium-ion copper foil produced by the present invention DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] Example 1:

[0028] As Figure 1 shown, take the raw materials sulfuric acid and lead carbonate solution, a grain refiner, a wetting agent, and a high-level leveling agent, and then process the lithium-ion copper foil according to the following steps:

[0029] S1. Prepare the electrolyte: Mix sulfuric acid and lead carbonate solution to form the electrolyte, heat and keep the electrolyte warm. The concentration of sulfuric acid is 100 g / L - 110 g / L, the concentration of copper ions is 90 g / L - 95 g / L, the concentration of chloride ions is 20 mg / L - 30 mg / L, and the temperature of the electrolyte is 45°C - 55°C;

[0030] S2. Prepare the additives: Prepare a grain refiner, a wetting agent, and a high-level leveling agent. Mix and stir the grain refiner, wetting agent, and high-level leveling agent in the installed ratio to form a mixed additive. The grain refiner is sodium 3-mercapto-1-propanesulfonate, the wetting agent is alkyl alcohol polyoxyethylene polyoxypropylene ether, and the high-level leveling agent is a nitrogen-containing amine compound. The concentration of the grain refiner in the electrolyte is 4 ppm, the concentration of the wetting agent in the electrolyte is 1 ppm, and the concentration of the high-level leveling agent in the electrolyte is 10 ppm;

[0031] S3. Hull cell tabbing: Add the electrolyte and the mixed additive to the Hull cell and perform Hull cell tabbing on the electrolyte;

[0032] S4. Lithium copper foil electroplating: Place three lithium copper foils into the electrolyte in the Hull cell for electroplating. After electroplating, the lithium copper foils are successively washed with water, passivated with chromic anhydride, and dried;

[0033] S5. Finished product inspection: Peel the dried lithium copper foil from the cathode plate, label the three lithium copper foils as No. 1, No. 2, and No. 3 in sequence, and detect the glossiness and tensile strength.

[0034] Example 2:

[0035] As Figure 1 shown, take the raw materials sulfuric acid and lead carbonate solution, grain refiner, wetting agent, and high-level leveling agent, and then process the lithium copper foil according to the following steps:

[0036] S1. Prepare the electrolyte: Mix sulfuric acid and lead carbonate solution to form the electrolyte, heat and keep the electrolyte warm. The concentration of sulfuric acid is 100 g / L - 110 g / L, the concentration of copper ions is 90 g / L - 95 g / L, the concentration of chloride ions is 20 mg / L - 30 mg / L, and the temperature of the electrolyte is 45°C - 55°C;

[0037] S2. Prepare the additives: Prepare a grain refiner, a wetting agent, and a high-level leveling agent. Mix and stir the grain refiner, wetting agent, and high-level leveling agent in the installed ratio to form a mixed additive. The grain refiner is sodium 3-mercapto-1-propanesulfonate, the wetting agent is alkyl alcohol polyoxyethylene polyoxypropylene ether, and the high-level leveling agent is a nitrogen-containing amine compound. The concentration of the grain refiner in the electrolyte is 4 ppm, the concentration of the wetting agent in the electrolyte is 1.5 ppm, and the concentration of the high-level leveling agent in the electrolyte is 10 ppm;

[0038] S3. Hull Cell Slice: Add the electrolyte and the mixed additives into the Hull cell, and perform Hull cell slicing on the electrolyte;

[0039] S4. Lithium Copper Foil Electroplating: Put three pieces of lithium copper foil into the electrolyte in the Hull cell for electroplating. After electroplating, the lithium copper foil is successively washed with water, passivated with chromic anhydride, and dried;

[0040] S5. Finished Product Inspection: Peel the dried lithium copper foil from the cathode plate, mark the three pieces of lithium copper foil as No. 4, No. 5, and No. 6 in sequence, and detect the glossiness and tensile strength.

[0041] Example Three:

[0042] As Figure 1 shown, take the raw materials sulfuric acid and lead carbonate solution, grain refiner, wetting agent, high-level leveling agent, and then process the lithium copper foil according to the following steps:

[0043] S1. Prepare the electrolyte: Mix sulfuric acid and lead carbonate solution to make the electrolyte, heat and keep the electrolyte warm. The concentration of sulfuric acid is 100 g / L - 110 g / L, the concentration of copper ions is 90 g / L - 95 g / L, the concentration of chloride ions is 20 mg / L - 30 mg / L, and the temperature of the electrolyte is 45°C - 55°C;

[0044] S2. Prepare the additives: Prepare the grain refiner, wetting agent, and high-level leveling agent, and mix and stir the grain refiner, wetting agent, and high-level leveling agent in proportion to form a mixed additive. The grain refiner is 3-mercapto-1-propanesulfonic acid sodium salt, the wetting agent is alkyl alcohol polyoxyethylene polyoxypropylene ether, the high-level leveling agent is a nitrogen-containing amine compound. The concentration of the grain refiner in the electrolyte is 5 ppm, the concentration of the wetting agent in the electrolyte is 1.5 ppm, and the concentration of the high-level leveling agent in the electrolyte is 10 ppm;

[0045] S3. Hull Cell Slice: Add the electrolyte and the mixed additives into the Hull cell, and perform Hull cell slicing on the electrolyte;

[0046] S4. Lithium Copper Foil Electroplating: Put three pieces of lithium copper foil into the electrolyte in the Hull cell for electroplating. After electroplating, the lithium copper foil is successively washed with water, passivated with chromic anhydride, and dried;

[0047] S5. Finished Product Inspection: Peel the dried lithium copper foil from the cathode plate, mark the three pieces of lithium copper foil as No. 7, No. 8, and No. 9 in sequence, and detect the glossiness and tensile strength.

[0048] Example Four:

[0049] As Figure 1 shown, take the raw materials sulfuric acid and lead carbonate solution, grain refiner, wetting agent, high-level leveling agent, and then process the lithium copper foil according to the following steps:

[0050] S1. Prepare the electrolyte: Mix sulfuric acid and lead carbonate solution to make the electrolyte, heat and keep the electrolyte warm. The concentration of sulfuric acid is 100 g / L - 110 g / L, the concentration of copper ions is 90 g / L - 95 g / L, the concentration of chloride ions is 20 mg / L - 30 mg / L, and the temperature of the electrolyte is 45°C - 55°C;

[0051] S2. Prepare the additives: Prepare a grain refiner, a wetting agent, and a high-level leveling agent. Mix and stir the grain refiner, the wetting agent, and the high-level leveling agent in a certain proportion to form a mixed additive. The grain refiner is sodium mercaptoimidazole propanesulfonate, the wetting agent is alkyl alcohol polyoxyethylene polyoxypropylene ether, and the high-level leveling agent is a nitrogen-containing amine compound. The concentration of the grain refiner in the electrolyte is 5 ppm, the concentration of the wetting agent in the electrolyte is 1 ppm, and the concentration of the high-level leveling agent in the electrolyte is 10 ppm;

[0052] S3. Hull cell tabbing: Add the electrolyte and the mixed additive into the Hull cell, and perform Hull cell tabbing on the electrolyte;

[0053] S4. Lithium copper foil electroplating: Put three pieces of lithium copper foil into the electrolyte in the Hull cell for electroplating. After electroplating, the lithium copper foil is washed with water, passivated with chromic anhydride, and dried in sequence;

[0054] S5. Finished product inspection: Peel the dried lithium copper foil from the cathode plate, mark the three pieces of lithium copper foil as No. 10, No. 11, and No. 12 in sequence, and detect the glossiness and tensile strength.

[0055] Detect the physical properties of the lithium copper foil made in the above four examples, Figure 3 and Figure 5 make the optical magnified view of the lithium copper foil. The specific properties are shown in the following table:

[0056]

[0057] Based on the data in the above table, it can be seen that different types of grain refiners have a certain impact on the glossiness of the copper foil. Sodium mercaptoimidazole propanesulfonate can improve the glossiness of the copper foil. Therefore, a mixed grain refiner is used for production, in which 3-mercapto-1-propanesulfonate and sodium mercaptoimidazole propanesulfonate are mixed in a ratio of 1:1 to make the grain refiner, and then the production is carried out according to the following steps:

[0058] S1. Prepare the electrolyte: Mix sulfuric acid and lead carbonate solution to make the electrolyte, heat and keep the electrolyte warm. The concentration of sulfuric acid is 100 g / L - 110 g / L, the concentration of copper ions is 90 g / L - 95 g / L, the concentration of chloride ions is 20 mg / L - 30 mg / L, and the temperature of the electrolyte is 45°C - 55°C;

[0059] S2. Configure additives: Prepare grain refiners, wetting agents, and high-level leveling agents. Mix the grain refiners, wetting agents, and high-level leveling agents in a certain proportion and stir to form a mixed additive. The grain refiner is made by mixing sodium 3-mercapto-1-propanesulfonate and sodium mercaptoimidazole propanesulfonate in a ratio of 1:1. The wetting agent is alkyl alcohol polyoxyethylene polyoxypropylene ether, and the high-level leveling agent is a nitrogen-containing amine compound. The electrolyte concentration of the grain refiner is 5 ppm, the electrolyte concentration of the wetting agent is 1.5 ppm, and the electrolyte concentration of the high-level leveling agent is 10 ppm;

[0060] S3. Hull cell sheet making: Add the electrolyte and the mixed additive to the Hull cell and perform Hull cell sheet making on the electrolyte;

[0061] S4. Lithium copper foil electroplating: Place seven lithium copper foils into the electrolyte in the Hull cell for electroplating. After electroplating, the lithium copper foils are successively washed with water, passivated with chromic anhydride, and dried;

[0062] S5. Finished product inspection: Peel the dried lithium copper foil from the cathode plate and detect the glossiness and tensile strength.

[0063]

[0064] In terms of the performance of continuous production, the physical properties of the copper foil meet the requirements of our company and the performance is stable. During continuous production, the copper foil is uniform, without color difference stripes. From the microscopic structure, after adjusting the additive process, the overall grain size of the copper foil decreases, the foil surface becomes smoother, and the foil surface uniformity increases;

[0065] Through the adjustment of the additive process and the use of a new additive combination, the average value of the normal temperature tensile strength of the 6μm copper foil system in production is 70.9 kgf / mm 2 , the average value of the baked tensile strength is 33.332 kgf / mm 2 , the average value of the baked elongation is 9.33%. The 6μm copper foil produced has a uniform foil surface, no color difference stripes on the copper foil appearance, small and uniform copper foil grains.

[0066] The above has described a detailed implementation example of the present invention, but the content described is only a preferred implementation example of the present invention and cannot be considered as limiting the implementation scope of the present invention. All equivalent changes and improvements made according to the scope of the present invention application should still fall within the patent coverage scope of the present invention.

Claims

1. An improved production process for lithium-ion copper foil crinkled gauze, characterized in that, It includes the following steps: S1. Prepare the electrolyte: Mix sulfuric acid and lead carbonate to make the electrolyte, and heat and keep the electrolyte at a constant temperature; S2. Prepare the additive: Prepare a grain refiner, a wetting agent, and a high-level leveling agent, and mix and stir the grain refiner, the wetting agent, and the high-level leveling agent in proportion to form a mixed additive; S3. Perform Hull cell tabbing: Add the electrolyte and the mixed additive into the Hull cell, and perform Hull cell tabbing on the electrolyte; S4. Electroplate the lithium copper foil: Place the lithium copper foil into the electrolyte in the Hull cell for electroplating. After electroplating, the lithium copper foil is successively washed with water, passivated with chromic anhydride, and dried; S5. Conduct finished product inspection: Peel the dried lithium copper foil from the cathode plate, and detect the glossiness and tensile strength; In S1, the concentration of sulfuric acid is 100 g / L - 110 g / L, the concentration of copper ions is 90 g / L - 95 g / L, the concentration of chloride ions is 20 mg / L - 30 mg / L, and the temperature of the electrolyte is 45°C - 55°C; The grain refiner is made of sodium 3-mercapto-1-propanesulfonate, sodium mercaptoimidazole propanesulfonate, or any proportion of the two; The wetting agent is alkyl alcohol polyoxyethylene polyoxypropylene ether or alkylphenol polyoxyethylene polyoxypropylene ether; The high-level leveling agent is a nitrogen-containing amine compound; The electrolyte concentration of the grain refiner is 4 ppm - 5 ppm; The electrolyte concentration of the wetting agent is 1 ppm - 1.5 ppm; The electrolyte concentration of the high-level leveling agent is 10 ppm - 15 ppm.

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