METHOD AND SYSTEM FOR PRODUCING ELECTROLYTIC COPPER FOIL BY USING REVERSE FLOW OF COPPER SULFATE SOLUTION

Abstract

 Disclosed in the present invention are a method and system for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution. The system comprises a cathode drum and an anode cell. Upper ports at two sides of the anode cell are located at two sides of the cathode drum. The flowing copper sulfate solution is flowing in the anode cell. The outer surface of the cathode drum is partially soaked in the copper sulfate solution. A copper foil electroplated on the cathode drum is continuously peeled off and wound up as the cathode drum rotates. The method is as follows: the copper sulfate solution flows into the anode cell at least from the upper port of the anode cell on one side surface of the cathode drum. The present invention is simpler in structure than traditional raw foil systems and completely changes the history that the copper foil quality can be controlled only by additives. The roughness on the surface of the copper foil and the current densities of electrodepositing copper foils are controlled by controlling the flow rates of the copper sulfate solution on the surface of the cathode drum. The present invention simplifies the production, makes the control process simple and easy to operate, reduces the production cost, decreases the discharge of pollutants, contributes to environmental protection, and has significant economic and social efficiencies.

Description

Technical Field

[0001] The present invention belongs to the technical field of production of electrolytic copper foils, and more particularly relates to a method and system for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution. A bottom-feed flow of the copper sulfate solution in traditional anode cells is changed into a top-feed flow and the quality of the copper foil is controlled by changing the direction and flow rates of the copper sulfate solution, thus bringing unexpected good effect for the production of copper foils and completely breaking away from the history that the quality of the copper foil can be controlled by additives only.

Background Art

[0002] At present, lead anodes that are not environmental-friendly and easy to be corroded have been excluded in the production of electrolytic copper foils, and have been replaced with titanium iridium anodes which have conductive surface coatings. However, either the lead anodes or the titanium iridium anodes are used, the production processes thereof are not changed substantially. The copper sulfate solution in an anode cell is always fed from the bottom of the anode cell, overflowed out of the upper ports of the anode cell and returned to copper dissolving tanks. Copper foil production in the conventional production equipment and processes is as follows: a cathode drum with a surface roughness Ra less than 0.4 µm is soaked below its axis in an anode cell to which a copper sulfate solution is fed with a copper content of 70-110 g/L, an acid content of 80-130 g/L and the temperature of 40-65°C. Electric current is fed between the cathode drum and the anodes. The part of the cathode drum soaked in the copper sulfate solution is plated with the copper crystals according to the electrochemical principle. According to the electrodepositing constant: 1.186 g/A-h, the thickness of the copper foil plated on the surface of the cathode drum depends on the electrodepositing time and current density of the cathode drum in the copper sulfate solution. The thickness of the copper foil plated on the surface of the cathode drum can be changed by changing the rotating speeds of the cathode drum. The copper foils of different thicknesses can be obtained by continuously peeling off the copper foil plated on the surface of the cathode drum as the cathode drum rotates. The side of the copper foil against on the surface of the cathode drum is called the shiny side, and the other surface is called the matte side. Due to the polarization effect in the electrodepositing process, copper textures with irregularly mountain peaks will be produced on the matte side of the copper foil. Thicker copper foils have larger copper grains and higher roughnesses on the matte sides. The roughness Rz on the matte side of the copper foil is controlled through a method of adding additives (gelatin or modified gelatin, thiourea etc.) in the production processes. The complicate production processes are extremely difficult to control which are also the bottleneck of the copper foil production. They are also confidential proprietary processes for many copper foil manufacturing plants. And meanwhile, large amount of additives are added to the copper sulfate solution, so when the copper sulfate solution returned back to the copper dissolving tanks, the abovementioned additives need to be removed and several filtration devices are required to improve the quality of the copper sulfate solution which increase the burden of the filters. Since oxygen evolution takes place in the process of electrodepositing copper foils onto the cathode drum, large amount of bubbles are produced which can also affect electrodepositing results. Because the copper sulfate solution flows upwards, bubbles are removed from the upper ports of the anode cell by the copper sulfate solution to form acid mists, which oxidize copper foil surfaces just peeled off from the cathode drum. To solve such a problem, exhaust openings with high flow rates are arranged at the top of the anode cell, making the production equipment of the copper foil complicated and difficult to control.

[0003] Ever since electrolytic copper foils were commercialized by Yates in 1955, their production processes have never been changed substantially;i.e., they have been always produced in a mode of bottom solution feeding and upper overflowing. This mode is mainly used to maintain the concentrations of copper ions and additives. The fluid mechanics problems in the cell have never been solved.

[0004] No matter whether an overhead tank or an acid-resistant pump is used to supply the copper sulfate solution in copper foil electrodeposition, the flow rate is generally below 0.5 meters per second. The resulting copper foil textures are columnar structure. Although the textures and the physical properties of the copper foi can be changed with brightening additives at ambient, they are very unstable at high temperatures. Their tensile strengths attenuate considerably. Brightners generate many lattice defects, pinholes and curls. Such copper foils are not suitable for manufacturing high-grade circuit boards and lithium ion batteries.

[0005] In the process of copper foil electrolysis, copper atoms are deposited on cathode surface, and oxygen bubbles are generated on anode surface and are brought to the liquid surface by the bottom feed solution. Since acid mist produced together with copper sulfate harm both the surface of the copper foil and operators, it is necessary to maintain the cleanness of workshops with powerful exhaust equipment.

[0006] The bottom feed solution produces turbulent flow near the solution inlet, and its Reynolds number is far beyond 2000. Although a lot of manufacturers make great efforts on the design of feed pipes, they still cannot solve the phenomenon of uneven thickness profile. Thickness adjustment must rely upon a solution feeding valves and piano shield plates, and yet this adjustment method is only temporary and quite unstable, and also adjustment has to be done every one or two days. The piano shield plates can only be used once or twice and its expense is terribly high. This is particularly a big headache for the continuous production.

[0007] There are two types of bottom feed solutions, i.e. closed type and open type. The former is a 100% new solution, the latter consists of a new solution and an old solution simultaneously. In either way, the solution flow of anode between the left and the right side of the anode gap cannot be accurately controlled. It can only be assumed that half of the feed solutions flow on each side. The controllability of each flow on either side is very low.

[0008] The most prominent shortcoming of the bottom feed solution is that copper ions and additive concentration on the liquid surface at the anode cell are old electrolyzed solutions with low concentrations, A lot of bubbles accumulate on the liquid surface which result in larger resistance on the liquid surface. When both factors are merged, the current density on the liquid surface is lower than that below the liquid surface. This phenomenon is unfavorable for the formation of crystal nuclei when the cathode drum enters the liquid surface. In severe cases, this is a major factor that leads to copper foil curl and pinholes.

Summery of the Invention

[0009] The objective of the present invention is to provide, on the basis of the abovementioned problems, a technical solution, which involves a method and system for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution. A bottom-feed solution flow of the copper sulfate solution in traditional anode cells is changed into a top-feed solution flow with increasing flow rates. It brings unexpected good effects for the production of copper foils and completely breaking away from the history that the quality of the copper foil can be controlled by additives only.

[0010] In order to achieve the above objective, the technical solution of the present invention is as follows:

A method for producing an electrolytic copper foil by a the reverse flow of a copper sulfate solution, comprising a cathode drum and an arc-shaped anodes, and an anode cell formed by a gap between the cathode drum and the arc-shaped anodes. Upper ports at the two sides of the anode cell are located at the two sides of the cathode drum with one side being a foil exit side, a flowing copper sulfate solution is in the anode cell, the cathode drum rotates in the anode cell, the outer surface of the cathode drum is partially soaked in the copper sulfate solution, an electric current is fed between the cathode drum and the anodes, and copper foils electrodeposited on the cathode drum are continuously peeled off and wound up as the cathode drum rotates, wherein the method comprises: feeding the copper sulfate solution into the anode cell at least from one of the upper ports of the anode cell at both sides of the cathode drum.

[0011] A further optimized solution is that: the copper sulfate solution is fed into the anode cell from the upper port of the anode cell at the foil exit side of the cathode drum.

[0012] A further optimized solution is that: the copper sulfate solution is fed into the anode cell from bot of the upper ports of the anode cell on two side surfaces of the cathode drum and flows out from the bottom of the anode cell, the copper sulfate solution that flows out entrains bubbles generated by electroplating from the bottom of the anode cell.

[0013] A further optimized solution is that: the method further comprises: when the surface roughness of the copper foil is more than a set value, increasing the flow rate of the copper sulfate solution on the inflow side surface of the cathode drum; and when the surface roughness of the copper foil is less than the set value, decreasing the flow rate of the copper sulfate solution on the inflow side surface of the cathode drum.

[0014] A further optimized solution is that: under the process conditions of production of the electrolytic copper foil, the flow rate of the copper sulfate solution formed on the surface of the cathode drum is at least 0.5 m/s; the process conditions of production of the electrolytic copper foil comprise that: the copper content of the copper sulfate solution is 70-110 g/L, the acid content is 80-130 g/L, the temperature is 40-65°C, and the anodic current density is 50-85 amperes per square decimeter.

[0015] A further optimized solution is that: the copper sulfate solution is a mixture of a primary copper sulfate solution and a secondary copper sulfate solution, the primary copper sulfate solution is a source copper sulfate solution directly provided by a copper dissolving tank, and the secondary copper sulfate solution is an electroplated copper sulfate solution that flows out via the anode cell.

[0016] A further optimized solution is that: the ratio of the primary copper sulfate solution to the secondary copper sulfate solution in the mixture is not less than 1:2.

[0017] A system for implementing the method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution, comprises a cathode drum, semicircular arc-shaped anodes and copper dissolving tanks. The cathode drum is rotatably arranged in the arc-shaped anodes, an anode cell is formed by a gap arranged between the cathode drum and the arc-shaped anodes, an upper feed box for delivering the copper sulfate solution to the anode cell is arranged above the anodes, upper ports at two sides of the anode cell are located at two sides of the cathode drum respectively, with one side being a foil exit side, the anode cell is provided with a copper sulfate solution inflow port and a copper sulfate solution outflow port, and the copper dissolving tank is connected with a solution inlet of the upper feed box through a delivery pipeline; and wherein the system is also provided with a copper sulfate solution collection tank, the anode cell copper sulfate solution outflow port is connected with the collection tank, the collection tank is connected with the copper dissolving tank, the collection tank is connected to the solution inlet of the upper feed box through a copper sulfate solution circulation pump, and a solution outlet of the upper feed box is at least connected with the upper port of the anode cell at one side surface of the cathode drum through a copper sulfate solution delivery pipeline.

[0018] A further optimized solution is that: a total flow regulating valve is installed in a pipeline connecting the upper feed box and the anode feed box copper sulfate solution inflow port, an anode cell copper sulfate solution flow rate regulating valve is installed in a pipeline connecting the anode cell copper sulfate solution outflow port and the collection tank, and a flow rate regulating valve is installed in a pipeline connecting the copper sulfate solution circulation pump and the upper feed box.

[0019] A further optimized solution is that: the upper port of the anode cell at one side surface of the cathode drum is an upper port of the anode cell at the foil exit side of the cathode drum.

[0020] A further optimized solution is that: the solution outlet of the upper feed box is connected with the upper ports of the anode cell at two sides of the cathode drum through the copper sulfate solution delivery pipeline, and the anode cell copper sulfate solution outflow port is arranged at the bottom of the anode cell.

[0021] A further optimized solution is that: the length of the anode cell copper sulfate solution outflow port at the bottom of the anode cell is the length of the cathode drum, and the width of the outflow port is at least two times of the gap between the cathode drum and the arc-shaped anode.

[0022] A further optimized solution is that: copper sulfate solution fed diversion port with a width equal to that of the upper port of the anode cell is connected with the upper port of the anode cell, and the diversion port is provided with gate plates capable of adjusting the flow direction of the copper sulfate solution.

[0023] Comparing with the prior art, the present invention has the following advantages:

1. The history is completely changed that the copper foil quality can be controlled only by additives. The roughness on the surface of the copper foil and the current densities of copper electrodepositing are controlled by reversing the direction of the copper sulfate solution and the flow rate of the copper sulfate solution on the surface of the cathode drum. The present invention lowers the requirements for filtration equipment, simplifies the production flow, and makes the production control process simple and easy to operate.

2. The present invention reduces the requirements for filtration equipment, and is simpler than traditional foil production equipment, thereby reducing the production cost.

3. The production process of the present invention decreases the discharge of pollutants, is ial to environmental friendly, and has significant economic and social benefits.

[0024] The present invention will be described below in details in conjunction with the accompanying drawings and embodiments.

Summery of the Invention

[0025] The paragraph of Technical Field is given here.

Brief Description of the Drawings

[0026] 

Fig. 1 is a schematic flow diagram of the production process of the present invention;

Fig. 2 is a structure diagram of the system of the present invention;

Fig. 3 is a structure diagram of the copper sulfate solution feed diversion port at the upper end of the anode cell of the present invention.

Detailed Description of the Embodiments

Embodiment 1:

[0027] Referring to Fig. 1, shown is an embodiment of a method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution, including an anode cell 3 formed by a gap arranged between a cathode drum 1 and curved semicircular arc-shaped anodes 2, the gap between the anode and the cathode drum is usually kept between 8mm to 15mm, the upper ports at two sides of the anode cell are located at two sides of the cathode drum (i.e., two side surfaces of the cathode drum which are vertically separated along a central axis), with one side being a foil exit side. A flowing copper sulfate solution 4 is in the anode cell, the cathode drum rotates in the anode cell, and the outer surface of the cathode drum below its axis is soaked in the anode cell to which the copper sulfate solution having a copper content of 70-110 g/L and an acid content of 80-130 g/L and the temperature of 40-65°C is added. An electric current is fed between the cathode drum and the anode. As the cathode drum rotates, a copper foil 5 electroplated on the cathode drum is continuously peeled off and wound up by a wind-up roll 7 via a stripper roller 6 by means of electrochemical reaction. Wherein the copper sulfate solution is at least fed into the anode cell from the upper port of the anode cell on one side surface of the cathode drum, such that the copper sulfate solution forms a downward flow impulsive force (that is, a certain flow impulse force, which is opposite to a direction in which the copper sulfate solution produces bubbles and which takes away the bubbles downwards, is formed) on the inflow side surface of the cathode drum.

[0028] The preferred solution 1 of this embodiment is that: the upper port of the anode cell on one side surface is the upper port of the anode cell at the foil exit side of the cathode drum. That is: the copper sulfate solution is fed into the anode cell from the upper port 3-1 of the anode cell at the foil exit side of the cathode drum.

[0029] The preferred solution 2 of this embodiment is that: since the copper sulfate solution at least flows into the anode cell from the upper port of the anode cell on one side of the cathode drum, the copper sulfate solution can flow out of the anode cell either from the bottom of the anode cell or from the upper port of the anode cell on the other side of the cathode drum. In order to overcome the situation in which during the process of electrodepositing the copper ions in the copper sulfate solution onto the cathode drum, large amount of bubbles generated due to oxygen evolution are discharged from the upper ports of the anode cell, this preferred solution differs from the abovementioned solution is that the copper sulfate solution is fed into the anode cell from the upper ports of the anode cell on two side surfaces of the cathode drum and flows out from the bottom of the anode cell, and the copper sulfate solution that flows out entrains the bubbles generated by electroplating from the bottom of the anode cell. The bubbles are rapidly taken away by the copper sulfate solution that rapidly flows downwardly, thereby reducing and even eliminating the impact of these bubbles on the electrodeposited copper foil.

[0030] In the abovementioned solution, a further method comprises: when the surface roughness of of the copper foil is more than a set value, increasing the speed of the copper sulfate solution flowing out from the bottom of the anode cell, that is, increasing the flow rate of the copper sulfate solution on the surface of the cathode drum; and when the surface roughness of the copper foil is less than the set value, decreasing the speed of the copper sulfate solution flowing out from the bottom of the anode cell, that is, decreasing the flow rate of the copper sulfate solution on the surface of the cathode drum. The set value of the surface roughness of the copper foil, i.e. the Rz roughness on a matte side, is typically controlled to be less than 2.5 µm according to different requirements of different products.

[0031] In the abovementioned solution, in order to improve the polarization effect in the electrodepositing process, solve the impact of the bubbles on the quality of the copper foil and improve the roughness on the surface of the copper foil and the density of copper foil crystal grains, under the process conditions of production of the electrolytic copper foil, the flow rate of the copper sulfate solution formed on the surface of the cathode drum is at least 0.5 m/s and typically within a range from 0.5 to 0.9 m/s; the process conditions of production of the electrolytic copper foil comprise that: the copper content of the copper sulfate solution is 70-110 g/L, the acid content is 80-130 g/L, the temperature is 40-65°C, and the anodic current density is 50-85 amperes per square decimeter. Wherein, when the anodic current density is 70 amperes per square decimeter, it is preferable for the flow rate of the copper sulfate solution to be controlled at 0.7 m/s, so that the bubbles generated are taken away quickly.

[0032] And in the conventional processing methods, the copper sulfate solution in the anode cell is fed from the bottom and overflowed from the top, which keeps the flow rate of the copper sulfate solution formed on the surface of the cathode drum below 0.5 m/s all the time; if the flow rate is more than 0.5 m/s, a large amount of sulfuric acid mists will be taken out from the upper ports of the anode cell and the copper sulfate solution will flow out of the anode cell to produce a series of problems, thus upward adjustment is infeasible; and in this embodiment, the flow rate of the copper sulfate solution formed on the surface of the cathode drum can be at least 0.5 m/s by changing the flow direction of the copper sulfate solution in the anode cell, and the surface roughness of the copper foil is controlled by controlling the flow rate of the copper sulfate solution on the surface of the cathode drum. When the surface roughness of the copper foil is more than the set value, the speed of the copper sulfate solution flowing out of the anode cell is increased, that is, the flow rate of the copper sulfate solution is increased; and when the surface roughness of the copper foil is less than the set value, the speed of the copper sulfate solution flowing out from the bottom of the anode cell is decreased, that is, the flow rate of the copper sulfate solution is decreased; the set value of the surface roughness of the copper foil, i.e. the Rz roughness on a matte side is typically controlled to be less than 2.5 µm according to different requirements of different products.

Embodiment 2:

[0033] Given here is another embodiment of the method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution. This embodiment is an improvement based on embodiment 1. Reference is made to the contents disclosed in embodiment 1 and embodiment 2 for an understanding of the parts in this embodiment that are the same as those in embodiment 1 and embodiment 2, and the contents disclosed in embodiment 1 and embodiment 2 should also be regarded as the contents of this embodiment.

[0034] In the abovementioned embodiments, the demand on the source copper sulfate solution is raised in order to increase the flow rate of the copper sulfate solution formed on the surface of the cathode drum, which certainly will increase the demand on copper dissolving tanks to result in an increase in equipment investment. To address this issue, in this embodiment, the copper sulfate solution is a mixture of a primary copper sulfate solution and a secondary copper sulfate solution, the primary copper sulfate solution is a source copper sulfate solution directly provided by the copper dissolving tanks, and the secondary copper sulfate solution is an electroplated copper sulfate solution that flows out via the anode cell. Wherein, in order to keep the effect of the original process unaffected by variation of the copper content in the copper sulfate solution, the ratio of the primary copper sulfate solution to the secondary copper sulfate solution in the mixture in this embodiment is not less than 1:2, and the ratio of 7:3 is an optimum ratio, i.e., in 100% copper sulfate solution, the primary copper sulfate solution accounts for 70% and the secondary copper sulfate solution accounts for 30%.

Embodiment 3:

[0035] Referring to Fig. 2 and Fig. 3, shown is a system for the method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution according to embodiment 1 and embodiment 2. The system comprises a cathode drum 1, a semicircular arc-shaped anode 2 and a copper dissolving tank 12, wherein the cathode drum is rotatably arranged in the arc-shaped anodes, an anode cell 3 is formed by a gap arranged between the cathode drum and the arc-shaped anodes, the gap between the anode and the cathode drum is generally maintained between 8 mm to 15 mm; arranged on the anode cell is an upper feed box 13 for delivering the copper sulfate solution to the anode cell, and upper ports at two sides of the anode cell are respectively located at two radial sides of the cathode drum (i.e., the upper ports of the anode cell at the two side surfaces of the cathode drum vertically separated along a center axis), with one side of the two radial sides of the cathode drum being a foil exit side; the anode cell is provided with a copper sulfate solution inflow port and a copper sulfate solution outflow port, and the copper dissolving tanks are connected with a solution inlet of the upper feed box through a delivery pipeline 18; wherein the system is also provided with a copper sulfate solution reflux collection tank 8, the anode cell copper sulfate solution outflow port is connected with the collection tank, the collection tank is connected with the copper dissolving tank, the collection tank is connected to the solution inlet of the upper feed box through a copper sulfate solution circulation pump 9, and a solution outlet of the upper feed box is at least connected with the upper port of the anode cell on one side surface of the cathode drum through a copper sulfate solution delivery pipeline.

[0036] The copper dissolving tank is a traditional system tank for current copper foil factories, which comprises a copper dissolving pot, a heat exchanger, a filter and a solution reservoir, wherein the copper dissolving tank is connected with the solution inlet of the upper feed box through the delivery pipeline, and specifically, the solution reservoir of the copper dissolving tank is connected with the solution inlet of the upper feed box through pumps and the pipelines.

[0037] As an optimized solution 1, one side surface of the cathode drum in this embodiment refers to the foil exit side of the cathode drum, i.e. the upper port of the anode cell at one side surface of the cathode drum is the upper port of the anode cell at the foil exit side of the cathode drum.

[0038] As an optimized solution 2, since the anode cell copper sulfate solution inflow port is at least the upper port of the anode cell on one side of the cathode drum, the anode cell copper sulfate solution outflow port may be at the bottom of the anode cell, or at the upper port of the anode cell on the other side of the cathode drum. In this optimized solution, the solution outlet of the upper feed box is connected with the upper ports of the anode cell on two sides of the cathode drum through the copper sulfate solution delivery pipeline, and the anode cell copper sulfate solution outflow port is arranged on the bottom end of the anode cell (i.e. a groove with full-length is axially arranged at the bottom of the arc-shaped anodes), in order to overcome the situation in which during the process of electrodepositing the copper ions in the copper sulfate solution onto the cathode drum, a large amount of bubbles generated due to oxygen evolution are discharged from the upper ports of the anode cell.

[0039] Wherein, in order to realize control over the flow rate of the copper sulfate solution in the anode cell, the length of the anode cell copper sulfate solution outflow port at the bottom of the anode cell is the length of the cathode drum, and the width 19 of the outflow port is at least twice the gap between the cathode drum and the arc-shaped anode.

[0040] In this embodiment, a total flow regulating valve 15 is installed in a pipeline 14 connecting the upper feed box with the anode cell copper sulfate solution inflow port, an anode cell copper sulfate solution flow rate regulating valve 11 is installed in a pipeline 10 connecting the anode cell copper sulfate solution outflow port with the collection tank, and a copper sulfate solution reflux flow regulating valve 17 is installed in a pipeline 16 connecting the copper sulfate solution circulation pump with the upper feed box.

Embodiment 4:

[0041] This embodiment is an improvement based on embodiment 3. Reference is made to the contents disclosed in embodiment 3 for an understanding of the parts in this embodiment that are the same as those in embodiment 3, and the contents disclosed in embodiment 3 should also be regarded as the contents of this embodiment.

[0042] In this embodiment, the upper ports of the anode cell are connected with a copper sulfate solution feed diversion port 20 having the same width as that of the upper port of the anode cell, and gate plates 21 capable of adjusting the flow direction of the copper sulfate solution are installed in the diversion port. The thickness uniformity of the cross section of the copper foil can be adjusted by controlling the openings of the gate plates.

Claims

1. A method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution, comprising an anode cell formed by a gap provided between a cathode drum and an arc-shaped anodes, upper ports at two sides of the anode cell being located at two sides of the cathode drum with one side being a foil exit side, the flowing copper sulfate solution being in the anode cell, the cathode drum rotating in the anode cell, the outer surface of the cathode drum being partially soaked in the copper sulfate solution, an electric current being fed between the cathode drum and the anodes, a copper foil electroplated on the cathode drum being continuously peeled off and wound up as the cathode drum rotates, characterized in that the method comprises: feeding the copper sulfate solution into the anode cell from at least one of the upper ports of the anode cell.

2. The method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution according to claim 1, characterized in that the copper sulfate solution is fed into the anode cell from the upper port of the anode cell at the foil exit side of the cathode drum.

3. The method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution according to claim 1, characterized in that the copper sulfate solution is fed into the anode cell from the upper ports of the anode cell on two side surfaces of the cathode drum and flows out from the bottom of the anode cell, the copper sulfate solution that flows out entrains bubbles generated by electroplating from the anode cell.

4. The method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution according to claim 1, characterized in that the method further comprises: when the surface roughness of the copper foil is more than a set value, increasing the flow rate of the copper sulfate solution on the inflow side surface of the cathode drum; and when the surface roughness of the copper foil is less than the set value, decreasing the flow rate of the copper sulfate solution on the inflow side surface of the cathode drum.

5. The method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution according to one of claims 1-4, characterized in that under the process conditions of production of the electrolytic copper foil, the flow rate of the copper sulfate solution formed on the surface of the cathode drum is at least 0.5 m/s; the process conditions of producing of the electrolytic copper foil comprise that: the copper content of the copper sulfate solution is 70-110 g/L, the acid content is 80-130 g/L, the temperature is 40-65°C, and the current density is 50 - 85 amperes per square decimeter.

6. The method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution according to one of claims 1-4, characterized in that the copper sulfate solution is a mixture of a primary copper sulfate solution and a secondary copper sulfate solution. The primary copper sulfate solution is a source copper sulfate solution directly provided by copper dissolving tanks, and the secondary copper sulfate solution is an electroplated copper sulfate solution that flows out via the anode cell.

7. The method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution according to claim 6, characterized in that the ratio of the primary copper sulfate solution to the secondary copper sulfate solution in the mixture is more than 1:2.

8. A system for the method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution according to claim 1, comprising a cathode drum, semicircular arc-shaped anodes and copper dissolving tanks, the cathode drum being rotatably arranged in the arc-shaped anodes, an anode cell being formed by a gap arranged between the cathode drum and the arc-shaped anodes, an upper feed box for delivering the copper sulfate solution to the anode cell being arranged above the anode , upper ports at two sides of the anode cell being located at two sides of the cathode drum respectively with one side being a foil exit side, the anode cell being provided with a copper sulfate solution inflow port and a copper sulfate solution outflow port, the copper dissolving tanks being connected with a solution inlet of the upper feed box through a delivery pipeline, characterized in that the system is also provided with a copper sulfate solution collection tank, the anode cell copper sulfate solution outflow port is connected with the collection tank, the collection tank is connected with the copper dissolving tank, the collection tank is also connected to the solution inlet of the upper feed box through a copper sulfate solution circulation pump, and a solution inlet of the upper feed box is at least connected with one of the upper ports of the anode cell through a copper sulfate solution delivery pipeline.

9. The system for the method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution according to claim 8, characterized in that a flow regulating valve is installed in a pipeline connecting the upper feed box and the copper sulfate solution inflow port, an anode cell copper sulfate solution flow rate regulating valve is installed in a pipeline connecting the anode cell copper sulfate solution outflow port and the collection tank, and a copper sulfate solution flow rate regulating valve is installed in a pipeline connecting the copper sulfate solution circulation pump and the upper feed box.

10. The system for the method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution according to one of claim 8 and 9, characterized in that the upper port of the anode cell at one side surface of the cathode drum is an upper port of the anode cell at the foil exit side of the cathode drum.

11. The system for the method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution according to one of claims 8 and 9, characterized in that the solution outlet of the upper feed box is connected with the upper ports of the anode cell at two sides of the cathode drum through the copper sulfate solution delivery pipeline, and the anode cell copper sulfate solution outflow port is arranged at the bottom of the anode cell.

12. The system for the method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution according to claim 11, characterized in that the length of the anode cell copper sulfate solution outflow port at the bottom of the anode cell is the same length as the cathode drum, and the width of the outflow port is at least two times the gap between the cathode drum and the arc-shaped anode.

13. The system for the method for producing an electrolytic copper foil by the reverse flow of a copper sulfate solution according to claim 11, characterized in that a copper sulfate solution feed diversion port has a width equal to that of the upper port of the anode cell is connected with the upper port of the anode cell which is provided with gate plates capable of adjusting the flow direction of the copper sulfate solution.

Drawing