阅读说明：本技术 一种4.5微米高延展性铜箔的制备方法 (Preparation method of 4.5-micron high-ductility copper foil ) 是由 董朝龙 江泱 范远朋 于 2021-09-06 设计创作，主要内容包括：本发明公开了一种4.5微米高延展性铜箔的制备方法,该制备方法包括以下步骤：S1将纯度≥99.95%的阴极铜铜板或铜线加入含有硫酸的溶铜罐中,加热,将铜溶解制备成硫酸铜溶液；S2硫酸铜溶液经过多级过滤后进入电解液罐存储；S3在电解液罐中加入添加剂,所述添加剂包括光亮剂、走位剂、整平剂、同时含有聚乙二醇(PEG)和含有铵盐的改性基团的添加剂P；S4在电解液罐里加入盐酸水溶液；S5将电解液罐中的硫酸铜电解液输送到生箔机进行电解生箔。本发明的制备方法使铜箔结晶晶粒整体略微增大,晶粒均匀性提高,减少了晶界对位错的滑移阻碍,晶粒的取向中有利滑移面增加,提升了铜箔的塑性,从而达到实现铜箔高延展性的目的。(The invention discloses a preparation method of a 4.5-micron high-ductility copper foil, which comprises the following steps: s1, adding a cathode copper plate or copper wire with the purity of more than or equal to 99.95% into a copper dissolving tank containing sulfuric acid, heating, and dissolving copper to prepare a copper sulfate solution; s2, the copper sulfate solution is filtered in multiple stages and then enters an electrolyte tank for storage; s3, adding additives into the electrolyte tank, wherein the additives comprise brightening agents, displacement agents, leveling agents, and additives P which simultaneously contain polyethylene glycol (PEG) and modified groups containing ammonium salts; s4, adding a hydrochloric acid aqueous solution into the electrolyte tank; s5, the copper sulfate electrolyte in the electrolyte tank is conveyed to a foil forming machine to carry out electrolytic foil forming. The preparation method of the invention slightly enlarges the whole crystal grains of the copper foil, improves the uniformity of the crystal grains, reduces the slippage obstruction of the crystal boundary to dislocation, increases the slippage face in the orientation of the crystal grains, and improves the plasticity of the copper foil, thereby achieving the purpose of realizing the high ductility of the copper foil.)

1. A preparation method of a 4.5 micron high-ductility copper foil is characterized by comprising the following steps:

s1, adding a cathode copper plate or copper wire with the purity of more than or equal to 99.95% into a copper dissolving tank (1) containing sulfuric acid, heating, and dissolving copper to prepare a copper sulfate solution;

s2, the copper sulfate solution obtained in the step S1 is filtered in multiple stages and then enters an electrolyte tank (2) for storage;

s3, adding additives into the electrolytic solution tank (2), wherein the additives comprise a brightening agent, a position shifting agent, a leveling agent and an additive P which simultaneously contains polyethylene glycol and a modified group containing ammonium salt, the brightening agent is a sulfur-containing organic matter and is formed by mixing poly-dithio-dipropyl sodium sulfonate and sodium alcohol-thiopropane sulfonate, the position shifting agent contains polyvinyl alcohol or crown ether compounds, and the leveling agent is one or more than two of gelatin, polyethyleneimine or tetrahydrothiazole thioketone;

s4, adding a hydrochloric acid aqueous solution into the electrolyte tank (2);

s5, the copper sulfate electrolyte in the electrolyte tank (2) is conveyed to a foil forming machine (3) to carry out electrolytic foil forming.

2. The method according to claim 1, wherein the heating in S1 is performed by blowing high temperature air into the copper dissolving tank (1) by a screw fan.

3. The method as claimed in claim 1, wherein the step of S2 comprises coarse filtering the copper sulfate solution with a diatomite filter, and fine filtering with a safety precise filter.

4. The preparation method according to claim 1, wherein the additives are added into the electrolyte tank (2) in the step S3 through an A barrel (4), a B barrel (5), a C barrel (6) and a D barrel (7) respectively and through an additive pump according to different concentrations and requirements, and the A barrel (4), the B barrel (5), the C barrel (6) and the D barrel (7) respectively contain a brightening agent, a displacement agent, a leveling agent, and an additive P simultaneously containing polyethylene glycol (PEG) and a modifying group containing ammonium salt.

5. The preparation method according to claim 1, wherein the brightening agent in S3 contains 40-60 ml/L sodium polydithio-propane sulfonate, 60-70 ml/L sodium thiopropane sulfonate, 0.5-2L/hr feed rate to the electrolyte tank (2), 10-20 ml/L displacement agent, 1-2L/hr feed rate to the electrolyte tank (2), 20-30 g/L leveling agent, 2-3L/hr feed rate to the electrolyte tank (2), 5-15 ml/L polyethylene glycol and 10-20 ml/L ammonium salt, the conveying flow rate of the electrolyte added into the electrolyte tank (2) is 1-2 liters/hour.

6. The method according to claim 1, wherein the step of adding the hydrochloric acid aqueous solution into the electrolyte tank (2) in S4 is carried out by adding the hydrochloric acid aqueous solution into the electrolyte tank (2) through an E barrel by an additive pump according to different concentrations and requirements.

7. The preparation method according to claim 1, wherein the concentration of the hydrochloric acid aqueous solution in the S4 is 0.1-0.3%, the flow rate of the hydrochloric acid aqueous solution added into the electrolyte tank is 2-5L/L, and the concentration of chloride ions in the electrolyte is controlled to be 30-40 mg/L.

8. The method as claimed in claim 1, wherein the copper sulfate electrolyte in S5 has a copper ion concentration of 80-90 g/L, a sulfuric acid content of 110-120 g/L, a copper sulfate electrolyte flow rate of 40-50 cubic meter/hour, and an electrolyte temperature of 50-60 ℃.

9. The method according to claim 1, wherein the current value of the green foil machine (3) in S5 is 20000-30000A.

Technical Field

The invention relates to the technical field of electrolytic copper foil, in particular to a preparation method of a 4.5-micron high-ductility copper foil.

Background

From the distribution of the industrial chain of the lithium electrolytic copper foil, the lithium electrolytic copper foil is mainly used for a negative current collector of a lithium battery, and the lithium battery is mainly used for a new energy automobile power battery, a 3C digital code and an energy storage system. As the demand of power batteries continues to increase, the global production of lithium-ion copper foil is also on an increasing trend year by year. The simplest lithium ion battery consists of a positive electrode, a negative electrode, a diaphragm, electrolyte and positive and negative current collectors. The metal foil (copper foil and aluminum foil) is a main material of the lithium ion battery, and has the function of collecting current generated by battery active substances so as to form larger current output. In the production process of the lithium battery, the negative electrode slurry is usually coated on a lithium battery copper foil, and then the processes of drying, rolling, slitting and the like are carried out, so that a negative electrode plate of the lithium battery is obtained.

The production process, the cost and the performance of the final product of the lithium battery are closely related to the factors such as the tensile strength, the ductility, the surface roughness, the thickness uniformity, the appearance quality and the like of the copper foil. In general, in hybrid and pure electric vehicles, pure electric vehicles are equipped with more battery units, and the weight of copper foil can reach more than 10Kg, so that the weight of copper foil on the battery can be reduced, on one hand, the raw material cost of the copper foil can be effectively reduced, and on the other hand, under the condition that the battery capacity is not changed, the weight of a single battery can be effectively reduced by using the copper foil with thinner thickness, so that the energy density of the battery is improved. The 4.5 micron copper foil as referred to in this case can increase the energy density by more than 10% compared with the current 6 micron copper foil in the market.

Reducing the thickness of the copper foil is one of the mainstream ways to increase the energy density of the lithium battery cell, so as to increase the demand of the electric vehicle for endurance and battery capacity density, the thinning of the copper foil has become a major development trend. Due to the trend of thinning and thinning of the copper foil, the copper foil is required to have higher ductility and tensile strength, but the 4.5 micron copper foil is relatively thin, so that the ductility of the material is lower, and the elongation of the 4.5 micron copper foil is about 30% lower than that of the 6 micron copper foil under the same process condition. In summary, to improve the energy density of the lithium ion battery, it is an optimal scheme to reduce the thickness of the copper foil of the negative current collector material in the lithium ion battery material, and the ductility of the copper foil needs to be improved in order to meet the production process and use requirements of the lithium battery after the copper foil is reduced.

In order to solve the problems in the technology, the production process analysis of the electrolytic copper foil shows that the number of crystal grains in a unit area is reduced, the number of crystal boundaries is reduced along with the reduction of the crystal grains, the blocking effect on dislocation motion is weakened, the slippage of dislocation is facilitated, and the improvement of plasticity is facilitated. In contrast, the ductility and tensile strength of many copper foils cannot meet the demand of lithium battery thinning development at present because the formulation process for copper foil manufacture cannot optimize the crystal structure of the copper foil. By adopting the scheme of the invention, through the synergistic effect of various additives, and the addition of the additive P simultaneously containing polyethylene glycol (PEG) and a modified group containing ammonium salt, and the action of matching chloride ions in a hydrochloric acid aqueous solution, the method plays an important role in regulating and controlling the surface activity and the interface adhesion of the cathode, improving the size and the uniformity of crystal grains in the copper deposition process, increasing the crystallization strength, reducing the crystal boundary defects, achieving the purpose of increasing the elongation of the copper foil and meeting the requirement of the development trend of thinning and thinning the copper foil of the lithium ion battery.

Disclosure of Invention

In view of the above technical problems in the related art, the present invention provides a method for preparing a 4.5 μm high-ductility copper foil, which can overcome the above disadvantages in the prior art.

In order to achieve the technical purpose, the technical scheme of the invention is realized as follows:

a preparation method of a 4.5 micron high-ductility copper foil is characterized by comprising the following steps:

s1, adding a cathode copper plate or copper wire with the purity of more than or equal to 99.95% into a copper dissolving tank containing sulfuric acid, heating, and dissolving copper to prepare a copper sulfate solution;

s2, the copper sulfate solution is filtered in multiple stages and then enters an electrolyte tank for storage;

s3, adding additives into an electrolyte tank, wherein the additives comprise a brightening agent, a position-shifting agent, a leveling agent and an additive P which simultaneously contains polyethylene glycol (PEG) and a modified group containing ammonium salt, the brightening agent is a sulfur-containing organic matter and is formed by mixing poly (di-thio) dipropyl sodium sulfonate and sodium alcohol-thio-propane sulfonate, the position-shifting agent contains polyvinyl alcohol or crown ether compounds, and the leveling agent is one or more than two of gelatin, polyethyleneimine or tetrahydrothiazole thioketone;

s4, adding a hydrochloric acid aqueous solution into the electrolyte tank;

s5, the copper sulfate electrolyte in the electrolyte tank is conveyed to a foil forming machine to carry out electrolytic foil forming.

Further, in the heating mode in the step S1, high-temperature air is blown into the copper dissolving tank by a screw fan.

Further, in the step S2, the multi-stage filtration is to coarsely filter the copper sulfate solution through a diatomite filter, and finely filter the copper sulfate solution through a safety precise filter.

Further, in the S3 process, the additives are added into the electrolyte tank through an a barrel, a B barrel, a C barrel, and a D barrel, respectively, and through an additive pump according to different concentrations and required amounts, wherein the a barrel, the B barrel, the C barrel, and the D barrel respectively contain a brightener, a placement agent, a leveling agent, and an additive P simultaneously containing polyethylene glycol (PEG) and a modifying group containing an ammonium salt.

Furthermore, the concentration of the sodium polydithio-dipropyl sulfonate in the brightener in S3 is 40-60 ml/L, the concentration of the sodium thiopropyl sulfonate in alcohol is 60-70 ml/L, and when the conveying flow rate to the electrolyte tank is 0.5-2L/L, the preparation concentration of the displacement agent is 10-20 ml/L, the conveying flow rate added into the electrolyte tank is 1-2 l/L, the preparation concentration of the leveling agent is 20-30 g/L, the conveying flow rate of the leveling agent added into the electrolyte tank is 2-3L/L, meanwhile, the preparation concentration of polyethylene glycol (PEG) in the modified group additive P containing polyethylene glycol (PEG) and ammonium salt is 5-15 ml/l, the preparation concentration of ammonium salt is 10-20 ml/l, and the conveying flow rate of the modified group additive P added into the electrolyte tank is 1-2 l/h.

Further, in the step S4, the hydrochloric acid aqueous solution is added to the electrolyte tank by adding the hydrochloric acid aqueous solution in the barrel E to the electrolyte tank through the additive pump.

Further, the concentration of the hydrochloric acid aqueous solution in the S4 is 0.1-0.3%, the flow rate of the hydrochloric acid aqueous solution added into the electrolyte tank is 2-5 liters/L, and the concentration of chloride ions in the electrolyte is controlled to be 30-40 mg/L.

Further, the copper ion concentration in the copper sulfate electrolyte in S5 is 80-90 g/L, the sulfuric acid content is 110-120 g/L, the copper sulfate electrolyte flow is 40-50 cubic meter/hour, and the electrolyte temperature is 50-60 ℃.

Further, the value of the current of the foil generator in S5 is 20000A-30000A.

The invention has the beneficial effects that: the preparation method of the invention slightly enlarges the whole crystal grains of the copper foil, improves the uniformity of the crystal grains, reduces the slippage obstruction of the crystal boundary to dislocation, increases the slippage face in the orientation of the crystal grains, and improves the plasticity of the copper foil, thereby achieving the purpose of realizing the high ductility of the copper foil.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a flow chart of a method of preparation according to an embodiment of the present invention;

in the figure: 1. a copper dissolving tank 2, an electrolytic solution tank 3, a foil forming machine 4, a barrel A, a barrel 5, a barrel B, a barrel 6, a barrel C, a barrel 7, a barrel D, a barrel 8 and a barrel E.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.

As shown in fig. 1, the method for preparing a 4.5 μm high-ductility copper foil according to an embodiment of the present invention includes the following steps:

s1, adding a cathode copper plate or copper wire with the purity of more than or equal to 99.95% into a copper dissolving tank 1 containing sulfuric acid, heating, and dissolving copper to prepare a copper sulfate solution;

s2, the copper sulfate solution obtained in the step S1 is subjected to multi-stage filtration and then enters an electrolyte tank 2 for storage;

s3, adding additives into the electrolyte tank 2, wherein the additives comprise a brightening agent, a position shifting agent, a leveling agent and an additive P which simultaneously contains polyethylene glycol and a modified group containing ammonium salt, the brightening agent is a sulfur-containing organic matter and is formed by mixing poly (di-thio) dipropyl sodium sulfonate and alcoholic thiopropane sodium sulfonate, the position shifting agent contains polyvinyl alcohol or crown ether compounds, and the leveling agent is one or more than two of gelatin, polyethyleneimine or thiazolidinethione;

s4, adding a hydrochloric acid aqueous solution into the electrolyte tank 2;

s5, the copper sulfate electrolyte in the electrolyte tank 2 is conveyed to the foil forming machine 3 to carry out electrolytic foil forming.

In the heating mode in the step S1, high-temperature air is blown into the copper dissolving tank 1 by a screw fan.

The multi-stage filtration in S2 is to coarsely filter the copper sulfate solution through a diatomite filter, and finely filter the copper sulfate solution through a safety precise filter.

The additive is added into the electrolyte tank 2 in the step S3 through an A barrel 4, a B barrel 5, a C barrel 6 and a D barrel 7 respectively and through an additive pump according to different concentrations and requirements, wherein the A barrel 4, the B barrel 5, the C barrel 6 and the D barrel 7 respectively contain a brightener, a displacement agent, a leveling agent, and an additive P simultaneously containing polyethylene glycol (PEG) and a modifying group containing ammonium salt.

The concentration of the sodium polydithio-dipropyl sulfonate in the brightener in the S3 is 40-60 ml/L, the concentration of the sodium thiopropyl alcoholate is 60-70 ml/L, when the conveying flow rate of the sodium dithio-dipropyl sulfonate added into the electrolyte tank 2 is 0.5-2L/L, the preparation concentration of the displacement agent is 10-20 ml/L, when the conveying flow added into the electrolyte tank 2 is 1-2 l/L, the preparation concentration of the leveling agent is 20-30 g/L, the conveying flow rate of the leveling agent added into the electrolyte tank 2 is 2-3L/L, meanwhile, the preparation concentration of the polyethylene glycol in the modification group additive P containing the polyethylene glycol and ammonium salt is 5-15 ml/l, the preparation concentration of the ammonium salt is 10-20 ml/l, and the conveying flow rate of the additive added into the electrolyte tank 2 is 1-2 l/h.

The hydrochloric acid aqueous solution is added into the electrolyte tank 2 in the above-mentioned S4, and is added into the electrolyte tank 2 through the additive pump according to different concentrations and required amounts by the barrel E.

The concentration of the hydrochloric acid aqueous solution in the S4 is 0.1-0.3%, the flow rate of the hydrochloric acid aqueous solution added into the electrolyte tank is 2-5 liters/L, and the concentration of chloride ions in the electrolyte is controlled to be 30-40 mg/L.

The copper ion concentration in the copper sulfate electrolyte in the S5 is 80-90 g/L, the sulfuric acid content is 110-120 g/L, the copper sulfate electrolyte flow is 40-50 cubic meter/hour, and the electrolyte temperature is 50-60 ℃.

The current value of the foil forming machine 3 in S5 is 20000-30000A.

When the method is used specifically, the electrolytic foil generation speed of the preparation method is 6-10 m/min, and the unit area mass of the prepared copper foil is 38-42 g/m. The prepared copper foil has the smooth surface roughness Ra of less than or equal to 0.30 micron, the rough surface roughness Rz of 1-2.5 microns, the ductility of the 4.5 micron copper foil in long-term production can reach 8-10%, and the tensile strength can reach more than 33 kg/mm.

In conclusion, by means of the technical scheme, the whole crystal grains of the copper foil are slightly enlarged, the uniformity of the crystal grains is improved, the slippage resistance of the grain boundary to dislocation is reduced, the increase of the slippage surface in the orientation of the crystal grains is facilitated, and the plasticity of the copper foil is improved, so that the purpose of realizing the high ductility of the copper foil is achieved.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.