Manufacturing method of double-sided coarse electrolytic copper foil

Abstract

The invention discloses a manufacturing method of a double-sided coarse electrolytic copper foil, which comprises the following steps: adding a copper wire or a copper plate into a copper dissolving tank, adding a sulfuric acid solution, introducing air, dissolving the copper wire or the copper plate under a high-temperature condition to generate a copper sulfate electrolyte, carrying out primary filtration on the copper sulfate electrolyte through a diatomite filter, and conveying the filtered copper sulfate electrolyte into a clean liquid tank; adding an additive into the clean liquid tank to obtain a first mixed electrolyte; the first mixed electrolyte is conveyed into a fine filter for secondary filtration, an additive is added at the same time, a second mixed electrolyte is obtained, the second mixed electrolyte is guided into a crude foil machine for electroplating, and crude electrolytic copper foil is obtained through production; the electrolytic copper foil raw foil is subjected to water washing, water squeezing and air draft and then guided into a coarsening tank, the copper foil is subjected to smooth surface coarsening treatment, finally, the copper foil is wound through a liquid squeezing roller and a winding roller, and the double-sided coarse copper foil is obtained; and placing the double-sided crude copper foil in a drying oven for annealing treatment to obtain a target product. According to the invention, the electrolytic copper foil with high roughness on both sides can be prepared.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electrolytic copper foil, in particular to a manufacturing method of double-sided rough electrolytic copper foil. BACKGROUND

[0002] As the negative current collector of lithium ion batteries, electrolytic copper foil is an important component of the electrode structure of lithium ion batteries. It not only serves as the carrier of the negative active material of the electrode, but also plays a role in collecting and transmitting current, which has a great influence on the internal resistance, charge-discharge performance and cycle performance of lithium ion batteries. In addition, due to its high electrical conductivity and thermal conductivity, electrolytic copper foil is widely used in printed circuit boards and electronic components, and is one of the essential materials in electronic products. With the rapid development of modern electronic industry, especially the popularization of new energy vehicles, energy storage systems and high-end electronic products, the performance requirements of lithium ion batteries are becoming higher and higher. Double-sided rough electrolytic copper foil can effectively increase the contact area with electrolyte or active material due to its unique rough surface, improve the charge-discharge performance and cycle life of the battery, and meet the market demand for high-performance batteries. At the same time, its manufacturing cost is relatively low, which helps to reduce the overall cost of lithium ion batteries and improve market competitiveness. Therefore, the manufacturing of double-sided rough electrolytic copper foil is of great significance. SUMMARY

[0003] To solve the above problems, the purpose of the present application is to provide a manufacturing method of double-sided rough electrolytic copper foil.

[0004] To achieve the above-mentioned purpose of the application, the technical scheme adopted by the present application is as follows:

[0005] A manufacturing method of double-sided rough electrolytic copper foil, comprising the following steps:

[0006] S1, adding raw material copper wire or copper plate into a copper dissolving tank, adding sulfuric acid solution and passing in air to make it dissolve to generate copper sulfate electrolyte under high temperature condition of 70-90℃, the copper sulfate electrolyte is filtered once by diatomite filter and delivered to a clean liquid tank; the copper ion concentration in the copper sulfate electrolyte is 80-95g / L, the sulfuric acid concentration is 90-110g / L, and the chloride ion concentration is 15-25ppm;

[0007] S2, adding an additive into the clean liquid tank in step S1 to obtain a first mixed electrolyte; the additive includes hydroxyethyl cellulose, collagen and polydithiodipropyl sulfonate sodium;

[0008] S3, delivering the first mixed electrolyte in step S2 to a precision filter for secondary filtration, while adding polydithiodipropyl sulfonate sodium as an additive to obtain a second mixed electrolyte; and introducing the second mixed electrolyte into a foil forming machine for electroplating; adjusting the solution temperature, current and additive dosage in the stage of green foil electroplating to produce electrolytic copper foil green foil.

[0009] S4, the electrolytic copper foil in step S3 is introduced into a roughening tank after water washing, water squeezing and air suction, and the copper foil is subjected to bright roughening treatment by adjusting solution flow, temperature and solution parameters, and finally is rolled by a squeezing roller and a winding roller to obtain a double-side rough copper foil; the pressure control of the water washing step is 0.3-0.5 MPa;

[0010] S5, the double-side rough copper foil in step S4 is placed in an oven for annealing and slow cooling to obtain a target product.

[0011] Further, in step S2, the concentration of hydroxyethyl cellulose is 5-10 g / L, the concentration of collagen is 6-11 g / L, and the concentration of sodium polydithiopropyl sulfone is 6.5-10.5 g / L.

[0012] Further, in step S2, the additive further comprises hydrochloric acid, and the concentration of hydrochloric acid is 15-25 ppm.

[0013] Further, in step S3, the concentration of copper ions in the second mixed electrolyte is 80-95 g / L, the concentration of sulfuric acid is 90-110 g / L, and the concentration of chloride ions is 15-25 ppm.

[0014] Further, in step S3, the electroplating process is operated according to conventional technology, the current density during the production of the foil is 38-45 A / dm 2 , the voltage is 4-5 V, the speed of the cathode roller is 5-9 m / min, the temperature of the liquid is controlled to be 50-55℃ by a plate exchanger, the flow of the liquid is 45-55 m 3 / h, the current density is controlled to be 38-45 A / dm 2 by a control panel, the thickness of the copper foil is controlled by the speed of the cathode roller, and the electrolytic copper foil with a thickness of 8-12 μm is prepared.

[0015] Further, in step S4, the conditions of the bright roughening treatment are as follows: the concentration of copper ions is 10-40 g / L, the concentration of sulfuric acid is 110-120 g / L, the temperature is 40-50℃, the flow is controlled to be 10-15 m 3 / h, the roughening current density is 20-40 A / dm 2 , and the speed is controlled by the speed of the cathode roller.

[0016] Further, in step S5, the annealing temperature is 50-65℃, and the annealing time is 8-14 h.

[0017] A double-side rough electrolytic copper foil is prepared by the method for manufacturing a double-side rough electrolytic copper foil.

[0018] The application has the following advantages due to the technical scheme as described above.

[0019] The manufacturing method of the double-side rough electrolytic copper foil of the application significantly improves the roughness of the rough surface of the copper foil by precisely controlling the type and amount of the additive in the foil growth and plating stage, so that the roughness of the smooth surface is more than 2 μm; then, the roughness of the smooth surface of the copper foil is simultaneously improved by optimizing the current density, solution flow and temperature key parameters in the roughening treatment stage; through the above step-by-step synergistic control process, the electrolytic copper foil with high roughness on both sides is finally prepared. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is the micro-SEM image of the rough surface of the double-side rough electrolytic copper foil in Example 1;

[0021] Figure 2 is the micro-SEM image of the smooth surface of the double-side rough electrolytic copper foil in Example 1;

[0022] Figure 3 is the micro-SEM image of the rough surface of the double-side rough electrolytic copper foil in Example 2;

[0023] Figure 4 is the micro-SEM image of the smooth surface of the double-side rough electrolytic copper foil in Example 2;

[0024] Figure 5 is the micro-SEM image of the rough surface of the double-side rough electrolytic copper foil in Example 3;

[0025] Figure 6 is the micro-SEM image of the smooth surface of the double-side rough electrolytic copper foil in Example 3;

[0026] Figure 7 is the micro-SEM image of the rough surface of the double-side rough electrolytic copper foil in Example 3;

[0027] Figure 8 is the micro-SEM image of the smooth surface of the double-side rough electrolytic copper foil in Example 3. DETAILED DESCRIPTION

[0028] The application can be further illustrated with reference to the following examples; however, the following examples are only illustrative, and the application is not limited to these examples.

[0029] Example 1

[0030] A manufacturing method of a double-side rough electrolytic copper foil, which comprises the following specific steps:

[0031] S1, the purity of 99.99 % copper wire is added to the copper dissolving tank, sulfuric acid solution is added and air is introduced to dissolve it at 85 DEG C high temperature to generate copper sulfate electrolyte, the copper sulfate electrolyte is filtered once through diatomite filter, and is transported to the clean liquid tank, the copper sulfate solution in the clean liquid tank is filtered twice through the precision filter to obtain pure electrolyte; the copper ion concentration in the copper sulfate electrolyte is 80-95 g / L, the sulfuric acid concentration is 90-110 g / L, and the chloride ion concentration is 15-25 ppm;

[0032] S2, the hydroxyethyl cellulose, collagen and polydithiodipropyl sulfone sodium in the additive are mixed with water respectively and placed in different preparation tanks, and the additive is added to the clean liquid tank through the preparation tank to obtain the first mixed electrolyte; wherein the concentration of hydroxyethyl cellulose is 7.5 g / L, the concentration of collagen is 8.5 g / L, and the concentration of polydithiodipropyl sulfone sodium is 7 g / L;

[0033] S3, the first mixed electrolyte is transported to the precision filter for secondary filtration, and polydithiodipropyl sulfone sodium is added to obtain the second mixed electrolyte, and the concentration of polydithiodipropyl sulfone sodium is 5.5 g / L; and the second mixed electrolyte is introduced into the foil machine for electroplating; the copper ion concentration in the second mixed electrolyte is 80-95 g / L, the sulfuric acid concentration is 90-110 g / L, and the chloride ion concentration is 15-25 ppm, the temperature of the liquid is controlled to be 50 DEG C by the plate exchange, and the flow rate is 45 m 3 / h; the current density is controlled to be 4500 A / dm 2 by the control panel, the thickness of the copper foil is controlled by the line speed of the cathode roller, and a 12 μm electrolytic copper foil is prepared;

[0034] S4, the electrolytic copper foil in step S3 is washed with water, squeezed, and air-dried, and the water washing pressure is controlled to be 0.3-0.5 MPa, and the purpose of water washing and air-drying is to remove the copper sulfate solution on the surface of the copper foil;

[0035] The treated electrolytic copper foil is introduced into the roughening tank for smooth roughening treatment, and the operation is as follows: a layer of copper layer with fine crystal particles, regular arrangement and smooth surface is formed on the surface of the rough copper foil as a roughening layer; after smooth roughening, a layer of copper tumor point with uniform coverage, dense crystal and fine particles is formed on the surface of the copper foil; the tumor point particles replace the smooth contour of the copper foil surface, which can effectively increase the contact area with the electrolyte or active material, improve the charge-discharge performance and cycle life of the lithium ion battery; the copper ion concentration in the roughening tank is 35 g / L, the sulfuric acid concentration is 115 g / L, the temperature is 45 DEG C, the flow rate is controlled to be 15 m 3 / h, and the roughening current density is 35 A / dm 2 , the line speed of the foil machine is controlled by the speed of the cathode roller; finally, the liquid is squeezed by the squeezing roller and wound by the winding roller to obtain a double-sided rough copper foil;

[0036] S5, the double-sided rough copper foil in step S4 is placed in an oven for annealing. The annealing treatment can increase the grain size of the copper foil and release internal stress to some extent. The annealing temperature is 60°C, the annealing time is 10h, and the cooling speed is 20°C / h. The target product is obtained, the roughness of the matte surface is 2.09μm, and the roughness of the bright surface after roughening in the roughening tank is 2.07μm. The micrographs of the bright surface and the matte surface of the double-sided rough electrolytic copper foil are shown in Figure 1 、 2 .

[0037] Example 2

[0038] A method for manufacturing a double-sided rough electrolytic copper foil. In the foil-making electroplating process, the collagen concentration is adjusted to 9g / L, and other electrolytic parameters are the same as in Example 1.

[0039] The process parameters in the roughening stage are the same as in Example 1.

[0040] The annealing temperature and the cooling speed are the same as in Example 1.

[0041] The double-sided rough electrolytic copper foil obtained in Example 2 has a matte surface roughness of 2.63μm, and a bright surface roughness of 2.11μm after roughening in the roughening tank. The micrographs of the bright surface and the matte surface of the double-sided rough electrolytic copper foil are shown in Figure 3 、 4 .

[0042] Example 3

[0043] A method for manufacturing a double-sided rough electrolytic copper foil. The foil-making electroplating process is the same as in Example 1.

[0044] In the roughening process, the roughening current is adjusted to 38A / dm 2 .

[0045] The annealing temperature and the cooling speed are the same as in Example 1.

[0046] The double-sided rough electrolytic copper foil obtained in Example 3 has a matte surface roughness of 2.03μm, and a bright surface roughness of 2.18μm after roughening in the roughening tank. The micrographs of the bright surface and the matte surface of the double-sided rough electrolytic copper foil are shown in Figure 5 、 6 .

[0047] Example 4

[0048] A method for manufacturing a double-sided rough electrolytic copper foil. The foil-making electroplating process is the same as in Example 3. The collagen concentration is adjusted to 11g / L, and the hydroxyethyl cellulose concentration is adjusted to 9g / L.

[0049] The process parameters of the roughening process, the roughening current is adjusted to 40A / dm 2 ;

[0050] The annealing temperature, time and cooling speed are the same as those in Example 1.

[0051] The roughness of the double-side roughened electrolytic copper foil obtained in Example 4 is 3.00μm for the rough surface and 2.3μm for the smooth surface after roughening in the roughening tank; the micrographs of the smooth surface and the rough surface of the double-side roughened electrolytic copper foil are shown in Figs. 2 and 3, respectively. Figure 7 、 8

[0052] Test Example

[0053] Roughness of the rough surface and the smooth surface after roughening in the roughening tank

[0054] The tensile testing machine is used to test the room temperature elongation of the 35μm treated foil (the sample size is 12.7x150mm 2 ), and the average value of the three-point elongation of the whole width is taken.

[0055] The data in Examples 1-4 are compared, and the results are shown in Table 1.

[0056] Table 1

[0057]

[0058] Through the comparison of the data in Example 1 and Example 3, it can be observed that when the concentration of the additive is relatively small, the roughness of the copper foil rough surface is relatively small; at the same time, through the comparison of the roughening current in Examples 1-4, it is shown that the appropriate increase of the roughening current can effectively improve the roughness of the copper foil smooth surface, and the increase of the concentration of collagen and hydroxyethyl cellulose in the leveling agent can effectively improve the roughness of the copper foil.

[0059] The above only describes the preferred embodiments of the present application and should not be used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.​

Claims

1. A method for manufacturing a double-sided rough electrolytic copper foil, characterized by: It includes the following steps: S1. Add raw material copper wire or copper plate into a copper dissolving tank, add sulfuric acid solution and introduce air to dissolve it at a high temperature of 70-90°C to generate copper sulfate electrolyte, and filter the copper sulfate electrolyte through a diatomaceous earth filter and transport it to a clean liquid tank; the copper sulfate electrolyte has a copper ion concentration of 80-95g / L, a sulfuric acid concentration of 90-110g / L, and a chloride ion concentration of 15-25ppm; S2, adding additives to the clean liquid tank in step S1 to obtain a first mixed electrolyte; the additives include hydroxyethyl cellulose, collagen, and sodium polydisulfide dipropane sulfonate; S3, transferring the first mixed electrolyte in step S2 to a fine filter for secondary filtration, and adding an additive, sodium polydipropylene disulfide sulfonate, to obtain a second mixed electrolyte; and introducing the second mixed electrolyte into a foil machine for electroplating; in the foil electroplating stage, adjusting the upper liquid temperature, current, and additive dosage of the solution to produce electrolytic copper foil; S4. After the electrolytic copper foil in step S3 is washed, squeezed, and ventilated, it is introduced into a roughening tank, and the copper foil is roughened on the surface by adjusting the solution flow, temperature, and solution parameters. Finally, it is rolled up by a squeezing roller and a winding roller to obtain a double-sided rough copper foil; the pressure of the water washing step is controlled to be 0.3-0.5 MPa; S5. Place the double-sided rough copper foil in step S4 in an oven for annealing and slowly cool to obtain the target product.

2. The method for manufacturing a double-sided rough electrolytic copper foil according to claim 1, wherein: In step S2, the concentration of hydroxyethyl cellulose is 5-10 g / L, the concentration of collagen is 6-11 g / L, and the concentration of sodium polydisulfide propane sulfonate is 6.5-10.5 g / L.

3. The method for producing a double-sided rough electrolytic copper foil according to claim 1 or 2, wherein: In step S2, the additive further includes hydrochloric acid, and the concentration of the hydrochloric acid is 15 to 25 ppm.

4. The method for manufacturing a double-sided rough electrolytic copper foil according to claim 1, wherein: In step S3, the copper ion concentration in the second mixed electrolyte is 80-95 g / L, the sulfuric acid concentration is 90-110 g / L, and the chloride ion concentration is 15-25 ppm.

5. The method for manufacturing a double-sided rough electrolytic copper foil according to claim 1, wherein: In step S3, the electroplating process is carried out according to conventional technology, and the current density during the production of foil is 38-45A / dm 2 , the voltage is 4~5V, the cathode roller speed is 5~9m / min, the upper liquid temperature is controlled at 50~55℃ by plate change, and the upper liquid flow rate is 45~55m 3 / h, and the current density is controlled by the control panel to be 38~45A / dm 2 By controlling the linear speed of the cathode roller to control the thickness of the copper foil, an electrolytic copper foil with a thickness of 8 to 12 μm is prepared.

6. The method for producing a double-sided rough electrolytic copper foil according to claim 1 or 5, wherein: In step S4, the conditions for the surface roughening treatment are: copper ion concentration of 10-40 g / L, sulfuric acid concentration of 110-120 g / L, temperature of 40-50 ° C, flow rate of 10-15 m 3 / h, the coarsening current density is 20~40A / dm 2 , the vehicle speed is controlled by the cathode roller speed.

7. The method for manufacturing a double-sided rough electrolytic copper foil according to claim 1, wherein: In step S5, the annealing temperature is 50-65° C., and the annealing time is 8-14 hours.

8. A double-sided rough electrolytic copper foil, characterized by: The double-sided rough electrolytic copper foil is prepared by the method for manufacturing the double-sided rough electrolytic copper foil according to any one of claims 1 to 7.

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