Combined additive for ultra-thin copper foil and process for manufacturing ultra-thin copper foil

Abstract

The application provides a combined additive for ultra-thin copper foil and a process for manufacturing ultra-thin copper foil, and belongs to the technical field of preparing electrolytic copper foil. The combined additive comprises A agent, B agent, C agent, D agent, E agent and F agent. The A agent is collagen, the concentration of which in electrolyte is 3-5 g / L. The B agent is mercaptoimidazole sodium propyl sulfonate, the concentration of which in electrolyte is 1-3 g / L. The C agent is dimethylamide sodium propane sulfonate, the concentration of which in electrolyte is 1-3 g / L. The D agent is phenyl disulfide sodium propane sulfonate, the concentration of which in electrolyte is 0.5-1 g / L. The E agent is ethylene thiourea, the concentration of which in electrolyte is 0.2-0.5 g / L. The F agent is low-molecular protein, the concentration of which in electrolyte is 2-3.5 g / L. Through the application, suitable additives are selected, and the combined additive is formed by screening the amount of components, so that the crystal grain structure of the manufactured ultra-thin copper foil is uniform and small, so as to improve the tensile strength, elongation, gloss and other properties.

Description

Technical Field

[0001] This invention belongs to the technical field of preparing electrolytic copper foil, and specifically relates to a combined additive for ultra-thin copper foil and a process for manufacturing ultra-thin copper foil using the combined additive. Background Technology

[0002] Lithium-ion batteries possess advantages such as high energy density, high operating voltage, low self-discharge, and no memory effect, making them the most widely used electrochemical energy storage system. They are extensively applied in consumer electronics, electric vehicles, and energy storage power stations. Lithium-ion battery copper foil is one of the key components, serving to conduct electricity and support the negative electrode active material. To meet the ever-increasing energy density demands of lithium-ion batteries, the future development of lithium-ion battery copper foil will inevitably move towards thinner and lighter designs. Generally, copper foil refers to copper thin film materials with a thickness of less than 200μm; 6μm and below are considered ultra-thin copper foil. The thinner the lithium-ion battery copper foil, the lighter the copper foil per unit area, and the higher the battery energy density. However, as lithium-ion battery copper foil products become thinner, defects in its microstructure lead to low tensile strength, low elongation, and poor gloss, affecting the performance of thin copper foil. To address the shortcomings of thin copper foil, such as low tensile strength, low elongation, and poor gloss, it is necessary to modify the microstructure of the copper foil. Existing technologies achieve this by controlling the concentration of copper ions, acid concentration, current density, and additive composition in the electrolyte, with modifying the additive composition being the most important method.

[0003] Additives can regulate the performance of copper foil by altering the microstructure of the coating. Currently, most additives used in lithium-ion battery copper foil manufacturing consist of gelatin, hydroxyethyl cellulose, and SPS, resulting in copper foils with poor thickness uniformity, large and porous crystal structures. Furthermore, lithium-ion batteries made from copper foil using these additives have relatively small volumetric capacity, high internal resistance, and shortened battery life. For ultra-thin copper foils, the choice of additive formulation is particularly crucial due to their thinness. Although there are numerous studies on the effects of additives on the tensile strength, elongation, and roughness of copper foils, research reports on ultra-thin lithium-ion battery copper foils with a thickness ≤6μm are still relatively few.

[0004] Therefore, how to select appropriate additives to manufacture ultra-thin copper foil with the best comprehensive performance (tensile strength, elongation, gloss, etc.) is an urgent issue to be solved in this technical field. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a combination additive for ultra-thin copper foil and a process for manufacturing ultra-thin copper foil using the combination additive. By selecting an appropriate combination ratio of additives, the manufactured ultra-thin copper foil can possess optimal comprehensive properties such as tensile strength, elongation, and gloss.

[0006] On one hand, the invention provides a combined additive for ultra-thin copper foil, comprising agent A, agent B, agent C, agent D, agent E, and agent F; agent A is collagen, with a concentration of 3-5 g / L in the electrolyte; agent B is sodium mercaptoimidazolium propanesulfonate, with a concentration of 1-3 g / L in the electrolyte; agent C is sodium dimethylamidopropanesulfonate, with a concentration of 1-3 g / L in the electrolyte; agent D is sodium phenyl dithiopropanesulfonate, with a concentration of 0.5-1 g / L in the electrolyte; agent E is ethylene thiourea, with a concentration of 0.2-0.5 g / L in the electrolyte; and agent F is a low molecular weight protein, with a concentration of 2-3.5 g / L in the electrolyte.

[0007] Preferably, agent A is collagen with a molecular weight of 1500-3000 da.

[0008] Preferably, the low molecular weight protein is collagen with a molecular weight of 500 to 800 da.

[0009] Preferably, the combined additives for the ultrathin copper foil include agents A, B, C, D, E, and F, which are present in the electrolyte at concentrations of 3.5 g / L, 1.8 g / L, 2.2 g / L, 0.8 g / L, 0.3 g / L, and 3 g / L, respectively.

[0010] On the other hand, the invention provides a process for manufacturing ultrathin copper foil using the above-mentioned combined additives, comprising:

[0011] The copper dissolution process involves dissolving raw copper rods in a sulfuric acid solution to generate copper sulfate electrolyte. The copper ion content, sulfuric acid concentration, chloride ion content, and temperature in the copper sulfate electrolyte are adjusted to meet the specified range.

[0012] Electrolytic foil making process;

[0013] Anti-oxidation process;

[0014] The electrolytic foil-making process includes:

[0015] The copper sulfate electrolyte is filtered and then transferred to the clean solution tank.

[0016] Add the combined additives for ultra-thin copper foil to the clean liquid tank at a feed rate of 0.5-1 L / h;

[0017] A copper sulfate electrolyte containing a combination of additives for ultra-thin copper foil is supplied at a flow rate of 50–70 m³ / h. 3 The copper sulfate electrolyte is fed into the electrolytic cell of the foil-making machine at a rate of / h, and flows from top to bottom into the anode cell, so as to continuously electrolyze and form ultra-thin copper foil on the surface of the cathode roller.

[0018] Preferably, in the copper dissolving process, the specified range is: copper ion content 70-90 g / L, sulfuric acid concentration 90-110 g / L, chloride ion content 40-60 ppm, and copper sulfate electrolyte temperature 50-55°C.

[0019] Preferably, in the copper dissolving process, the specified range is: copper ion content 80 g / L, sulfuric acid concentration 90 g / L, and chloride ion content 50 ppm.

[0020] Preferably, the foil-making machine includes an arc-shaped anode, a cathode roller that rotates relative to the arc-shaped anode, and a pipeline; an anode groove is formed between the cathode roller and the arc-shaped anode, and an upper groove for conveying copper sulfate electrolyte to the anode groove is provided on the anode groove, and the outlet of the upper groove is connected to the upper port of the anode groove on one side of the cathode roller through the pipeline.

[0021] Preferably, the anti-oxidation process includes washing the ultra-thin copper foil with an electrolyte, rinsing it with pure water, and drying it to obtain an ultra-thin copper foil with high surface cleanliness; then installing an anti-oxidation treatment tank for micro-electroplating on the foil production machine, and after the ultra-thin copper foil with high surface cleanliness undergoes anti-oxidation treatment using chemical plating or chemical micro-electroplating processes, it is air-dried to obtain a dry anti-oxidation ultra-thin copper foil.

[0022] Preferably, the ultrathin copper foil has a thickness uniformity deviation of 0.2 μm, a surface roughness Rz of less than 1.5 μm, and a tensile strength greater than 45 kgf / mm². 2 Elongation greater than 6%, gloss level of 300–600 units, and wettability greater than 50 × 10⁻⁶ units. -3 N / m.

[0023] The combined additive for ultra-thin copper foil and the process for manufacturing ultra-thin copper foil using the combined additive provided in the embodiments of the present invention have at least the following technical effects:

[0024] 1. By selecting collagen, sodium mercaptoimidazolium propanesulfonate, sodium dimethylamidopropanesulfonate, sodium phenyl dithiopropanesulfonate, ethylene thiourea, and low molecular weight protein, and by screening and compounding the amounts of the components, a combination additive for the production of ultra-thin copper foil is formed. This results in a uniform and fine grain structure in the manufactured ultra-thin copper foil, thereby improving tensile strength, elongation, gloss, and other properties, and achieving the best comprehensive performance of the ultra-thin copper foil.

[0025] 2. Based on the selected combination of additives and the use of appropriate parameters and conditional manufacturing processes, the tensile strength, elongation, gloss and other properties of ultra-thin copper foil can be further enhanced, thereby further improving the quality of ultra-thin copper foil. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 The SEM morphology image of the electrolytic copper foil provided in Comparative Example 1 of this invention is as follows: Figure 1 As shown;

[0028] Figure 2 The SEM image of the electrolytic copper foil provided in Comparative Example 2 of this invention is shown below. Figure 1 As shown;

[0029] Figure 3 The SEM morphology image of the electrolytic copper foil provided in Embodiment 1 of the present invention is as follows: Figure 1 As shown;

[0030] Figure 4 The SEM morphology image of the electrolytic copper foil provided in Embodiment 2 of the present invention is as follows: Figure 1 As shown. Detailed Implementation

[0031] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0032] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention.

[0033] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0034] The foil-making machine used in the embodiments of this invention employs a top-feed process, where the copper sulfate solution flows downwards into the anode tank. This change in the direction of the copper sulfate solution flow controls the surface quality of the copper foil. In traditional bottom-feed processes, the copper sulfate solution flows upwards, causing air bubbles to be carried out from the upper end of the anode tank, forming sulfuric acid fumes. This not only creates black spots on the copper foil surface but also pollutes the workshop air, affecting employee health. The top-feed foil-making machine system mainly consists of a cathode roller, a semi-circular anode, and piping. The specific structure is as follows: The cathode roller can rotate within the arc-shaped anode. The gap between the cathode roller and the arc-shaped anode forms an anode groove. An upper tank for conveying copper sulfate solution to the anode groove is set on the anode groove. The outlet of the upper tank is connected to the upper port of the anode groove on one side of the cathode roller through a copper sulfate solution conveying pipe. The upper ports on both sides of the anode groove are located on both sides of the cathode roller, with one side being the foil exit side. The anode groove is equipped with a copper sulfate solution inflow port (this port is the upper port of the anode groove on one side of the cathode roller) and a copper sulfate solution outflow port (this port is located at the bottom of the anode groove). The copper dissolving system is connected to the inlet of the upper tank through a conveying pipe, and the copper sulfate solution outflow port of the anode groove is connected to the copper dissolving system. It should be noted that this foil making machine is similar to the traditional structure, except that the positions of each component are adjusted according to the liquid inlet method. Therefore, the specific schematic diagram and mechanism will not be elaborated.

[0035] Furthermore, the cathode roller is a chromium-plated stainless steel roller. During the electrolysis process, copper ions gradually deposit on the surface of the cathode roller and form electrolytic copper foil after being peeled off from the cathode roller. Although stainless steel has good corrosion resistance, its hardness is low. When the copper foil is peeled off from the cathode roller multiple times, the surface of the cathode roller is easily damaged. Chromium plating on the surface of stainless steel can significantly improve the hardness of stainless steel and enhance the surface wear resistance, thereby extending the service life of the cathode roller and improving the quality of the peeled copper foil. In other embodiments, a pure titanium roller can also be used as the cathode roller, and its function is similar to that of the chromium-plated stainless steel roller, which will not be elaborated here.

[0036] Comparative Example 1

[0037] I. Determination of Copper Foil Manufacturing Process Based on Copper Sulfate Electrolyte

[0038] In the production of electrolytic copper foil, the composition of the electrolyte and process conditions directly affect the appearance quality and physical properties of the electrolytic copper foil. The basic electrolyte mainly consists of copper sulfate, sulfuric acid, and chloride ions. First, experiments were conducted to determine the concentrations of sulfuric acid, copper ions, and chloride ions in the electrolyte. The composition of the electrolyte was then determined through evaluation of physical properties (tensile strength, elongation, and roughness). Specific experiments are as follows:

[0039] Experiments were conducted on the concentrations of sulfuric acid, copper ions, and chloride ions in the electrolyte without the addition of additives. Three different concentrations were selected for each condition, and nine sets of parameter combinations were designed (as shown in Table 1), at a current density of 60 A / dm³. -2 Electrodeposition of 12μm copper foil was carried out under the conditions of 50-55℃ and 900rpm.

[0040] Table 1: Nine parameter combinations for sulfuric acid concentration, copper ion concentration, and chloride ion concentration without additives.

[0041] Parameter group Copper ion concentration (g / L) Sulfuric acid concentration (g / L) Chloride ion content (ppm) Group D11 70 90 60 Group D12 70 100 40 Group D13 70 110 50 Group D14 80 90 50 Group D15 80 100 60 Group D16 80 110 40 Group D17 90 90 40 Group D18 90 100 60 Group D19 90 110 50

[0042] The tensile strength, elongation and roughness of 12μm thick copper foils obtained with different parameter sets were tested, and the test results are shown in Table 2.

[0043] Table 2: Physical properties of copper foil obtained from 9 parameter combinations without additives

[0044]

[0045]

[0046] As shown in Table 2, copper ion concentration is the most significant factor affecting the mechanical properties of electrolytic copper foil. When the copper ion concentration is 70–80 g / L, the physical properties of the copper foil are superior, with a tensile strength ranging from 31.4 to 34.6 gf / mm². 2 The elongation was 4.6–5.3%. The tensile strength decreased when the copper ion concentration was 90 g / L. Based on the experimental results, a copper ion concentration of 80 g / L was deemed more suitable.

[0047] Table 2 shows that when the copper ion concentration is 80 g / L, increasing the sulfuric acid concentration gradually decreases the tensile strength, although the change in tensile strength is not significant. When the copper ion concentration is 90 g / L, the elongation can be appropriately increased, but the tensile strength decreases. This is because when the copper ion concentration in the electrolyte increases, the high concentration of sulfuric acid can improve the dispersibility of the electrolyte and the flatness of the copper foil. Based on the experimental results, a sulfuric acid concentration of 90 g / L is more suitable.

[0048] As shown in Table 2, chloride ion concentration has a significant impact on the physical properties of copper foil. Under the same copper ion concentration, the physical properties are poor when the chloride ion concentration is 40 ppm and 60 ppm, with the tensile strength around 33 gf / mm². 2 At higher chloride ion concentrations, copper electrodeposition is accelerated, leading to coarse surface crystals and lower tensile strength and roughness. Based on experimental results, a chloride ion concentration of 50 ppm is considered appropriate.

[0049] In summary, the optimal experimental electrolyte concentrations for each factor were determined as follows: chloride ion concentration at 80 g / L, sulfuric acid concentration at 90 g / L, and chloride ion concentration at 50 ppm. Under these conditions, the tensile strength was 33.7 MPa, the elongation was 4.4%, and the surface roughness Rz was 5.49 μm. The corresponding SEM morphology of the electrolytic copper foil is shown in the figure below. Figure 1 As shown.

[0050] Comparative Example 2

[0051] For copper foil manufacturing, adding the right combination of additives to the base electrolyte can effectively improve the surface morphology and physical properties of the copper foil. Specifically, based on their function, additives can be broadly categorized into leveling agents, brighteners, and wetting agents. Currently, commonly used additive combinations use gelatin as a leveling agent, SPS as a brightener, and polyethylene glycol as a wetting agent. The nitrogen-containing functional groups in leveling agents are positively charged and selectively adsorb onto the active sites of the cathode, hindering the reduction of copper ions on the cathode surface, thereby achieving grain refinement. Their specific adsorption on protrusions on the coating surface can effectively improve the leveling properties of the coating. Brighteners are mostly heterocyclic compounds containing thiol groups, disulfides, etc. The synergistic effect between sulfonic acid groups and chloride ions accelerates the reduction of copper ions, which can fill defects on the copper foil surface, mainly used to improve the brightness of the coating. Wetting agents are mostly surfactants, which can promote the removal of bubbles, improve the dispersibility of the electrolyte, and reduce the formation of pinholes and pores. Specific experiments are as follows:

[0052] Under the conditions of an electrolyte with a chloride ion concentration of 80 g / L, a sulfuric acid concentration of 90 g / L, and a chloride ion concentration of 50 ppm, and with the addition of a commonly used additive combination of gelatin, SPS, and a wetting agent, experiments were conducted to test the concentrations of sulfuric acid, copper ions, and chloride ions in the electrolyte. Three different concentrations were selected for each condition, and nine sets of parameter combinations were designed (as shown in Table 3), at a current density of 60 A / dm³. -2 Electrodeposition of 12μm thick copper foil was carried out under the conditions of 50-55℃ and 900rpm.

[0053] Table 3: Nine parameter combinations with added common additives, including sulfuric acid concentration, copper ion concentration, and chloride ion concentration.

[0054] Parameter group Gelatin (g / L) SPS (g / L) Wetting agent (ppm) Group D21 3 1 0.2 Group D22 3 1 0.35 Group D23 3 1 0.5 Group D24 4 2 0.2 Group D25 4 2 0.35 Group D26 4 2 0.5 Group D27 5 3 0.2 Group D28 5 3 0.35 Group D29 5 3 0.5

[0055] The tensile strength, elongation and roughness of the copper foils obtained with different parameter groups were tested, and the test results are shown in Table 4.

[0056] Table 4: Physical properties of copper foil obtained by adding 9 sets of parameters with common additives

[0057]

[0058]

[0059] As shown in Table 4, under the conditions of an electrolyte with a chloride ion concentration of 80 g / L, a sulfuric acid concentration of 90 g / L, and a chloride ion concentration of 50 ppm, and with the addition of a combination of commonly used gelatin, SPS, and wetting agents, the physical properties of the 12 μm thick copper foil were significantly improved, with the tensile strength increasing to 35.9–39.4 gf / mm². 2 The elongation was increased to 4.8–5.6, and the roughness was increased to 3.70–3.42.

[0060] It should be noted that most additives used in the manufacture of lithium-ion battery copper foil are composed of gelatin, hydroxyethyl cellulose, SPS, etc. Although the material properties are significantly improved compared to copper foil manufactured without additives, the copper foil manufactured with commonly used additives has poor thickness uniformity and a larger, more porous crystal structure. Its crystal structure is as follows... Figure 2 As shown, compared to Figure 1 It can be seen that the crystal structure of copper foil manufactured with the addition of common additives has been improved to some extent, but the crystal structure is still relatively large and porous. Currently, the physical properties of 12μm thick copper foil manufactured with common additives are acceptable. However, the physical properties of ultrathin copper foil manufactured using the same additives are difficult to meet market requirements. The reason for this is that ultrathin copper foil is thinner, and the effect of the copper foil crystal structure will be further deteriorated. Therefore, the selection of additive formulations for ultrathin copper foil is particularly important. The following examples use the additives selected in this invention and combine them accordingly to obtain a combined additive for ultrathin copper foil, so as to improve the physical properties of ultrathin copper foil.

[0061] Example 1

[0062] This embodiment provides a combined additive for ultrathin copper foil, comprising agent A, agent B, agent C, agent D, and agent E. Agent A is collagen with a concentration of 3.5 g / L in the electrolyte; agent B is sodium mercaptoimidazolium propanesulfonate with a concentration of 1.8 g / L in the electrolyte; agent C is sodium dimethylamidopropanesulfonate with a concentration of 2.2 g / L in the electrolyte; agent D is sodium phenyl dithiopropanesulfonate with a concentration of 0.8 g / L in the electrolyte; and agent E is ethylene thiourea with a concentration of 0.3 g / L in the electrolyte. Specifically, the collagen is collagen with a molecular weight of 1500–3000 da.

[0063] This embodiment includes a process for manufacturing ultrathin copper foil using the aforementioned combined additives, comprising:

[0064] S101, copper dissolution process, which dissolves the raw copper rod in sulfuric acid solution to generate copper sulfate electrolyte.

[0065] Specifically, the copper sulfate electrolyte is adjusted to reach the specified range, including a copper ion content of 80 g / L, a sulfuric acid concentration of 90 g / L, a chloride ion content of 50 ppm, and a temperature of 50–55 °C.

[0066] S102, Electrolytic foil making process;

[0067] Specifically, firstly, the copper sulfate electrolyte is filtered and then transferred to a clean solution tank;

[0068] Secondly, add the combined additives for ultra-thin copper foil to the clean liquid tank at a feed rate of 0.8L / h;

[0069] Finally, the copper sulfate electrolyte containing the combined additives for ultra-thin copper foil is supplied at a flow rate of 60 m³ / h. 3 The copper sulfate electrolyte is fed into the electrolytic cell of the foil-making machine at a rate of / h, and flows from top to bottom into the anode cell to continuously electrolyze and form 4.5μm ultrathin copper foil on the cathode roller surface. It should be noted that by changing the direction of the copper sulfate solution flow into the anode cell from top to bottom, the surface quality of the copper foil is controlled. In the traditional bottom-feed process, the copper sulfate solution flows upwards, causing air bubbles to be carried out from the upper port of the anode cell, forming sulfuric acid fumes.

[0070] S103, anti-oxidation process;

[0071] Specifically, ultra-thin copper foil is subjected to electrolytic acid washing, pure water rinsing and drying to obtain ultra-thin copper foil with high surface cleanliness; then, an anti-oxidation treatment tank for micro-electroplating is installed on the foil production machine, and the ultra-thin copper foil with high surface cleanliness is subjected to anti-oxidation treatment using chemical plating or chemical micro-electroplating process and then air-dried to obtain a dry 4.5μm anti-oxidation ultra-thin copper foil with a thickness uniformity deviation of 0.8μm.

[0072] The physical properties of the ultrathin copper foil (4.5 μm) manufactured using the above-mentioned additive combination are shown in Table 5, and the crystal structure is as follows. Figure 3 As shown.

[0073] Table 5: Physical properties of ultrathin copper foil obtained with added additives (Agent A, Agent B, Agent C, Agent D, Agent E)

[0074] <![CDATA[Tensile strength (Kgf / mm 2 )]]> Elongation (%) Roughness (μm) Example 1 42.4 5.6 2.53

[0075] As can be seen from Tables 4 and 5, this embodiment, through the selection of additives and their corresponding concentrations, forms a combined additive. Adding this combined additive to the electrolyte to manufacture 4.5μm ultrathin copper foil results in physical properties that achieve the same performance as 12μm copper foil manufactured using conventional combined additives, with a significant improvement. This is because the coupling reaction of the combined additive in this embodiment reduces the nucleation surface energy, inhibits crystal growth rate, eliminates pinholes and micro-defects, increases the number of nuclei, refines the grain size, homogenizes the copper foil structure, and effectively improves tensile strength and elongation, thus enhancing tensile strength. Figure 2 and Figure 3 It can be seen that the crystal structure defects of the 4.5μm ultrathin copper foil manufactured in Example 1 are further improved compared with the crystal structure of the 12μm copper foil in Comparative Example 2.

[0076] Example 2

[0077] This embodiment provides a combined additive for ultra-thin copper foil, comprising agent A, agent B, agent C, agent D, agent E, and agent F. Agent A is collagen with a concentration of 3.5 g / L in the electrolyte; agent B is sodium mercaptoimidazolium propanesulfonate with a concentration of 1.8 g / L in the electrolyte; agent C is sodium dimethylamidopropanesulfonate with a concentration of 2.2 g / L in the electrolyte; agent D is sodium phenyl dithiopropanesulfonate with a concentration of 0.8 g / L in the electrolyte; agent E is ethylene thiourea with a concentration of 0.3 g / L in the electrolyte; and agent F is a low molecular weight protein with a concentration of 3 g / L in the electrolyte. Specifically, the collagen is collagen with a molecular weight of 1500–3000 da, and the low molecular weight protein is collagen with a molecular weight of 500–800 da.

[0078] The process for manufacturing ultrathin copper foil in this embodiment is similar to that in Example 1, and the thickness will not be described in detail here.

[0079] Using the above-mentioned additive combination, the thickness uniformity deviation of the manufactured ultrathin copper foil (4.5μm) is 0.2μm. The corresponding physical properties are shown in Table 6, and the crystal structure is as follows. Figure 4 As shown.

[0080] Table 6: Physical properties of ultrathin copper foil obtained with added: combined additives (Agent A, Agent B, Agent C, Agent D, Agent E, Agent F)

[0081] <![CDATA[Tensile strength (Kgf / mm 2 )]]> Elongation (%) Roughness (μm) Example 1 45.6 6.3 1.35

[0082] As can be seen from Tables 5 and 6, this embodiment, by further adding low-molecular-weight protein to the additive combination of Example 1, and adding this additive combination to the electrolyte to manufacture 4.5μm ultrathin copper foil, achieves further improvements in physical properties compared to Example 1. This is because adding an appropriate amount of low-molecular-weight protein to the electrolyte refines the grains, making the copper foil surface finer and smoother, thereby improving the copper foil elongation. Figure 3 and Figure 4 It can be seen that the crystal structure defects of the 4.5μm ultrathin copper foil manufactured in Example 2 are significantly improved compared with those of the 4.5μm ultrathin copper foil manufactured in Comparative Example 1.

[0083] Example 3

[0084] This embodiment provides a combined additive for ultra-thin copper foil, comprising agent A, agent B, agent C, agent D, agent E, and agent F. Agent A is collagen with a concentration of 3 g / L in the electrolyte; agent B is sodium mercaptoimidazolium propanesulfonate with a concentration of 1 g / L in the electrolyte; agent C is sodium dimethylamidopropanesulfonate with a concentration of 1 g / L in the electrolyte; agent D is sodium phenyl dithiopropanesulfonate with a concentration of 0.5 g / L in the electrolyte; agent E is ethylene thiourea with a concentration of 0.5 g / L in the electrolyte; and agent F is a low molecular weight protein with a concentration of 3.5 g / L in the electrolyte. Specifically, the collagen is collagen with a molecular weight of 1500–3000 da, and the low molecular weight protein is collagen with a molecular weight of 500–800 da.

[0085] This embodiment includes a process for manufacturing ultrathin copper foil using the aforementioned combined additives, comprising:

[0086] S111, copper dissolution process, which dissolves the raw copper rod in sulfuric acid solution to generate copper sulfate electrolyte.

[0087] Specifically, the copper sulfate electrolyte is adjusted to reach the specified range, including a copper ion content of 80 g / L, a sulfuric acid concentration of 90 g / L, a chloride ion content of 50 ppm, and a temperature of 50–55 °C.

[0088] S112, Electrolytic foil making process;

[0089] Specifically, firstly, the copper sulfate electrolyte is filtered and then transferred to a clean solution tank;

[0090] Secondly, add the combined additives for ultra-thin copper foil to the clean liquid tank at a feed rate of 1L / h;

[0091] Finally, the copper sulfate electrolyte containing the combined additives for ultra-thin copper foil is supplied at a flow rate of 70 m³ / h. 3The copper sulfate electrolyte is fed into the electrolytic cell of the foil-making machine at a rate of / h, and flows from top to bottom into the anode cell to continuously electrolyze and form 4.5μm ultrathin copper foil on the cathode roller surface. It should be noted that by changing the direction of the copper sulfate solution flow into the anode cell from top to bottom, the surface quality of the copper foil is controlled. In the traditional bottom-feed process, the copper sulfate solution flows upwards, causing air bubbles to be carried out from the upper port of the anode cell, forming sulfuric acid fumes.

[0092] S113, anti-oxidation process;

[0093] Specifically, ultra-thin copper foil is subjected to acid washing with electrolyte, rinsing with pure water and drying to obtain ultra-thin copper foil with high surface cleanliness; then, an anti-oxidation treatment tank for micro-electroplating is installed on the foil production machine, and the ultra-thin copper foil with high surface cleanliness is subjected to anti-oxidation treatment using chemical plating or chemical micro-electroplating process and then air-dried to obtain dry 4.5μm anti-oxidation ultra-thin copper foil.

[0094] Using the above-mentioned additive combination, the thickness uniformity deviation of the manufactured ultrathin copper foil (4.5μm) is 0.25μm, and the corresponding physical property results are shown in Table 7.

[0095] Table 7: Physical properties of ultrathin copper foil obtained with added: combined additives (Agent A, Agent B, Agent C, Agent D, Agent E, Agent F)

[0096] <![CDATA[Tensile strength (Kgf / mm 2 )]]> Elongation (%) Roughness (μm) Example 1 44.0 6.0 1.49

[0097] As can be seen from Tables 6 and 7, this embodiment adjusts the concentration of each additive based on the additive combination of Example 2. The concentrations of agent A, B, C, D, E, and F in the electrolyte are all 3 g / L, 1 g / L, 1 g / L, 0.5 g / L, and 0.5 g / L respectively. When this additive combination is added to the electrolyte to manufacture 4.5 μm ultrathin copper foil, the resulting physical properties show a certain degree of decrease compared to those of Example 2.

[0098] Example 4

[0099] This embodiment provides a combined additive for ultra-thin copper foil, comprising agent A, agent B, agent C, agent D, agent E, and agent F. Agent A is collagen with a concentration of 5 g / L in the electrolyte; agent B is sodium mercaptoimidazolium propanesulfonate with a concentration of 3 g / L in the electrolyte; agent C is sodium dimethylamidopropanesulfonate with a concentration of 3 g / L in the electrolyte; agent D is sodium phenyl dithiopropanesulfonate with a concentration of 1 g / L in the electrolyte; agent E is ethylene thiourea with a concentration of 0.2 g / L in the electrolyte; and agent F is a low molecular weight protein with a concentration of 2 g / L in the electrolyte. Specifically, the collagen is collagen with a molecular weight of 1500–3000 da, and the low molecular weight protein is collagen with a molecular weight of 500–800 da.

[0100] This embodiment includes a process for manufacturing ultrathin copper foil using the aforementioned combined additives, comprising:

[0101] S111, copper dissolution process, which dissolves the raw copper rod in sulfuric acid solution to generate copper sulfate electrolyte.

[0102] Specifically, the copper sulfate electrolyte is adjusted to reach the specified range, including a copper ion content of 80 g / L, a sulfuric acid concentration of 90 g / L, a chloride ion content of 50 ppm, and a temperature of 50–55 °C.

[0103] S112, Electrolytic foil making process;

[0104] Specifically, firstly, the copper sulfate electrolyte is filtered and then transferred to a clean solution tank;

[0105] Secondly, add the combined additives for ultra-thin copper foil to the clean liquid tank at a feed rate of 0.5L / h;

[0106] Finally, the copper sulfate electrolyte containing the combined additives for ultra-thin copper foil is supplied at a flow rate of 50 m³ / h. 3 The copper sulfate electrolyte is fed into the electrolytic cell of the foil-making machine at a rate of / h, and flows from top to bottom into the anode cell to continuously electrolyze and form 4.5μm ultrathin copper foil on the cathode roller surface. It should be noted that by changing the direction of the copper sulfate solution flow into the anode cell from top to bottom, the surface quality of the copper foil is controlled. In the traditional bottom-feed process, the copper sulfate solution flows upwards, causing air bubbles to be carried out from the upper port of the anode cell, forming sulfuric acid fumes.

[0107] S113, anti-oxidation process;

[0108] Specifically, ultra-thin copper foil is subjected to acid washing with electrolyte, rinsing with pure water and drying to obtain ultra-thin copper foil with high surface cleanliness; then, an anti-oxidation treatment tank for micro-electroplating is installed on the foil production machine, and the ultra-thin copper foil with high surface cleanliness is subjected to anti-oxidation treatment using chemical plating or chemical micro-electroplating process and then air-dried to obtain dry 4.5μm anti-oxidation ultra-thin copper foil.

[0109] Using the above-mentioned additive combination, the thickness uniformity deviation of the manufactured ultrathin copper foil (4.5μm) is 0.23μm, and the corresponding physical property results are shown in Table 8.

[0110] Table 8: Physical properties of ultrathin copper foil obtained with added: combined additives (Agent A, Agent B, Agent C, Agent D, Agent E, Agent F)

[0111] <![CDATA[Tensile strength (Kgf / mm 2 )]]> Elongation (%) Roughness (μm) Example 1 44.5 6.1 1.45

[0112] As can be seen from Tables 6 and 7, this embodiment adjusts the concentration of each additive based on the additive combination of Example 2. The concentrations of agent A, B, C, D, E, and F in the electrolyte are all 3 g / L, 1 g / L, 1 g / L, 0.5 g / L, and 0.5 g / L respectively. When this additive combination is added to the electrolyte to manufacture 4.5 μm ultrathin copper foil, the resulting physical properties show a certain degree of decrease compared to those of Example 2.

[0113] In summary, as described in Comparative Examples 1 and 2 and Examples 1-4, under the conditions of an electrolyte with a chloride ion concentration of 80 g / L, a sulfuric acid concentration of 90 g / L, and a chloride ion concentration of 50 ppm, the use of a combination of additives for ultra-thin copper foil, specifically including agents A, B, C, D, E, and F at concentrations of 3.5 g / L, 1.8 g / L, 2.2 g / L, 0.8 g / L, 0.3 g / L, and 3 g / L in the electrolyte, produces ultra-thin copper foil with the best physical properties. The thickness uniformity deviation is 0.2 μm, the surface roughness Rz is less than 1.5 μm, and the tensile strength is greater than 45 kgf / mm². 2 The elongation is greater than 6%.

[0114] 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, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A composite additive for ultra-thin copper foil, characterized in that, The solution includes agents A, B, C, D, E, and F. Agent A is collagen with a concentration of 3–5 g / L in the electrolyte. Agent B is sodium mercaptoimidazolium propanesulfonate with a concentration of 1–3 g / L in the electrolyte. Agent C is sodium dimethylamidopropanesulfonate with a concentration of 1–3 g / L in the electrolyte. Agent D is sodium phenyl dithiopropanesulfonate with a concentration of 0.5–1 g / L in the electrolyte. Agent E is ethylene thiourea with a concentration of 0.2–0.5 g / L in the electrolyte. Agent F is a low molecular weight protein with a concentration of 2–3.5 g / L in the electrolyte. The low molecular weight protein is collagen with a molecular weight of 500–800 da, and Agent A is collagen with a molecular weight of 1500–3000 da.

2. The combined additive for ultra-thin copper foil according to claim 1, characterized in that, The combined additives for ultra-thin copper foil include Agent A, Agent B, Agent C, Agent D, Agent E, and Agent F, which are present in the electrolyte at concentrations of 3.5 g / L, 1.8 g / L, 2.2 g / L, 0.8 g / L, 0.3 g / L, and 3 g / L, respectively.

3. A process for manufacturing ultra-thin copper foil using the combined additives for ultra-thin copper foil as described in claim 1 or 2, characterized in that, The process includes: The copper dissolution process involves dissolving raw copper rods in a sulfuric acid solution to generate copper sulfate electrolyte. The copper ion content, sulfuric acid concentration, chloride ion content, and temperature in the copper sulfate electrolyte are adjusted to meet the specified range. Electrolytic foil making process; Anti-oxidation process; The electrolytic foil-making process includes: The copper sulfate electrolyte is filtered and then transferred to the clean solution tank. Add the combined additives for ultra-thin copper foil to the clean liquid tank at a feed rate of 0.5-1 L / h; A copper sulfate electrolyte containing a combination of additives for ultra-thin copper foil is supplied at a flow rate of 50–70 m³ / h. 3 The copper sulfate electrolyte is fed into the electrolytic cell of the foil-making machine at a rate of / h, and flows from top to bottom into the anode cell, so as to continuously electrolyze and form ultra-thin copper foil on the surface of the cathode roller.

4. The process for manufacturing ultrathin copper foil according to claim 3, characterized in that, In the copper dissolving process, the specified ranges are: copper ion content 70-90 g / L, sulfuric acid concentration 90-110 g / L, chloride ion content 40-60 ppm, and copper sulfate electrolyte temperature 50-55°C.

5. The process for manufacturing ultrathin copper foil according to claim 4, characterized in that, In the copper dissolution process, the specified ranges are: copper ion content 80 g / L, sulfuric acid concentration 90 g / L, and chloride ion content 50 ppm.

6. The process for manufacturing ultrathin copper foil according to claim 3, characterized in that, The foil-making machine includes an arc-shaped anode, a cathode roller that rotates relative to the arc-shaped anode, and a pipeline; an anode groove is formed between the cathode roller and the arc-shaped anode, and an upper tank for conveying copper sulfate electrolyte to the anode groove is provided on the anode groove. The outlet of the upper tank is connected to the upper port of the anode groove on one side of the cathode roller through the pipeline.

7. The process for manufacturing ultrathin copper foil according to claim 3, characterized in that, The anti-oxidation process includes washing the ultra-thin copper foil with an electrolyte, rinsing it with pure water, and drying it to obtain an ultra-thin copper foil with high surface cleanliness; then installing an anti-oxidation treatment tank for micro-electroplating on the foil production machine, and after the ultra-thin copper foil with high surface cleanliness undergoes anti-oxidation treatment using chemical plating or chemical micro-electroplating processes, it is air-dried to obtain a dry anti-oxidation ultra-thin copper foil.

8. The process for manufacturing ultrathin copper foil according to claim 3, characterized in that, The ultrathin copper foil has a thickness uniformity deviation of 0.2 μm, a surface roughness Rz of less than 1.5 μm, and a tensile strength greater than 45 kgf / mm². 2 The elongation is greater than 6%.

Images