Electrolytic copper foil preparation method, electrolytic copper foil equipment and copper foil

Abstract

The invention relates to the technical field of electroforming, in particular to an electrolytic copper foil preparation method, electrolytic copper foil equipment and a copper foil. The preparation method comprises the following steps: detecting the copper ion concentration C < actual > in the electrolyte; setting a copper ion concentration reference value C parameter, and applying the following ultrasonic waves to the electrolyte for ultrasonic treatment according to the size relationship between the C real and the C parameter: when the C real is less than the C parameter, applying a first ultrasonic wave; when C real > = C parameter, applying a second ultrasonic wave; the frequency of the first ultrasonic is higher than that of the second ultrasonic; and the electrolyte subjected to ultrasonic treatment is guided into an electrolytic bath for electrolytic reaction treatment, copper foil is generated, in the electrolytic bath, direct current is supplied to a cathode part, and direct current and pulse current are supplied to an anode part. The electrolytic copper foil equipment comprises a cathode part, an anode part, an electrolytic bath, an electrolyte container, a detection device and an ultrasonic device. According to the preparation method, the mass transfer efficiency and the electric crystallization process are improved, and the prepared copper foil is low in surface roughness, small in thickness uniformity tolerance and high in tensile strength.

Description

Technical Field

[0001] The present application relates to the field of electroforming technology, and in particular to a method for preparing electrolytic copper foil, electrolytic copper foil equipment, and copper foil. Background Art

[0002] Electroforming is a process for producing metal products by depositing metal at the cathode through electrolytic reactions. Traditional electrolytic copper foil production processes mostly use mechanical stirring combined with direct current electrodeposition. However, it is generally not convenient to set up mechanical stirring in the electrolytic cell, and mechanical stirring has limited effects on the mass transfer efficiency of the electrolyte and the migration rate of copper ions. When the reduction rate of copper ions near the cathode is higher than the migration rate of copper ions, it is easy to cause concentration polarization, resulting in uneven local copper ion concentration, high surface roughness, the formation of dendrites with burrs, uneven thickness, Cu2O inclusion defects and other problems. When concentration polarization occurs, it is necessary to increase the current density to maintain the reaction rate, which will lead to an increase in the cell pressure of the electrolytic cell, increased energy consumption, and increased costs. The use of direct current electrodeposition easily causes copper ions to tend to grow on the crystal nucleus, making it difficult to form crystal nuclei, resulting in problems such as coarse copper foil grains and high surface roughness.

[0003] Existing improved technologies gradually adopt the scheme of applying ultrasound to the electrolyte, which is beneficial to increasing the migration rate of copper ions, improving the mass transfer efficiency of the electrolyte, and breaking the concentration polarization. However, the existing ultrasonic control technology only applies ultrasound blindly, and the improvement effect is limited. Other improved technologies apply pulse current to the anode to improve the electrodeposition process, but the fixed pulse parameters can only refine the grains to a certain extent, and it is difficult to improve the problem of unstable grain orientation. The effect of improving the surface roughness of the copper foil is also limited. Moreover, it is difficult for a single technical improvement to simultaneously optimize the mass transfer efficiency of the electrolyte and the control of the electrocrystallization process. Ultimately, the copper foil still has the above-mentioned problems such as high roughness. Summary of the Invention

[0004] The purpose of this application is to provide a method for preparing electrolytic copper foil, an electrolytic copper foil device, and copper foil, aiming to solve the problem in the prior art that copper foil produced by electroforming tends to have high roughness.

[0005] To achieve the above application objectives, the technical solutions adopted in this application are as follows:

[0006] In a first aspect, the present application provides a method for preparing an electrolytic copper foil, comprising the following steps:

[0007] Detect the copper ion concentration C in the electrolyte 实 ;

[0008] Set a copper ion concentration reference value C 参 , according to C 实 with C 参 The electrolyte is ultrasonically treated by applying the following ultrasonic wave:

[0009] When C 实 <C 参 When the first ultrasonic wave is applied;

[0010] When C 实 ≥C 参 When the second ultrasonic wave is applied;

[0011] The frequency of the first ultrasonic wave is higher than the frequency of the second ultrasonic wave;

[0012] The ultrasonically treated electrolyte is introduced into an electrolytic cell for electrolytic reaction to generate copper foil. In the electrolytic cell, direct current is passed through the cathode part, and direct current and pulse current are passed through the anode part.

[0013] The preparation method of this application sets the ultrasonic frequency according to the copper ion concentration in the electrolyte, which greatly improves the targeted effect of ultrasonic treatment. 实 , when C 实 <C 参 When C is low, the copper ion concentration in the electrolyte is low, the copper ion migration rate is low, and the mass transfer efficiency of the electrolyte is low, so a higher frequency first ultrasonic wave needs to be applied; when ... 实 ≥C 参 When the copper ion concentration in the electrolyte is high, the copper ion migration rate is relatively high, so only a second ultrasonic wave of lower frequency needs to be applied. In this way, ultrasonic waves of different frequencies are applied according to different copper ion concentrations, so that the copper ion migration rate in the electrolyte is increased and remains stable, the mass transfer efficiency of the electrolyte is improved, and it is compatible with the consumption rate of the cathode portion. On the one hand, the concentration polarization phenomenon is reduced, which is conducive to reducing copper dendrites, reducing burrs, and reducing the surface roughness of the obtained copper foil. On the other hand, it is conducive to uniform and stable electrocrystallization and electro-deposition processes. At the same time, the preparation method passes direct current and pulse current through the anode portion. The continuous direct current makes the copper ions more inclined to form larger and coarser grains, while the pulse current makes the copper ions more inclined to generate high-density, small, and evenly distributed crystal nuclei, and reduce the growth of crystal nuclei. Therefore, the introduction of pulse current is conducive to the refinement of the generated grains, optimizes the electrocrystallization process, and makes the electro-deposition more uniform, which is conducive to reducing the surface roughness of the copper foil. Therefore, the preparation method of the present application improves the copper ion migration rate and the electrocrystallization process by optimizing the ultrasonic frequency and introducing pulse current, alleviates the phenomenon of coarse grains, makes the electrodeposition process more uniform, and the prepared copper foil has low roughness and a smooth surface.

[0014] In a second aspect, the present application provides an electrolytic copper foil device, comprising:

[0015] a cathode portion connected to a DC power supply;

[0016] Anode part, connected to DC power supply and pulse power supply;

[0017] an electrolytic cell, wherein the cathode portion and the anode portion are disposed in the electrolytic cell;

[0018] an electrolyte container, connected to the electrolytic cell;

[0019] a detection device for detecting the copper ion concentration in the electrolyte in the electrolyte container cavity;

[0020] An ultrasonic device is used to apply ultrasonic waves to the electrolyte.

[0021] The detection device of the electrolytic copper foil equipment of the present application can detect the copper ion concentration in the electrolyte in the cavity. According to the detection result of the detection device, the ultrasonic device can apply frequency-adapted ultrasonic waves to the electrolyte, so that the migration rate of copper ions in the electrolyte is increased and maintained stable, the mass transfer efficiency is improved, and it is adapted to the consumption rate of the cathode part. On the one hand, it reduces the concentration polarization phenomenon, which is conducive to reducing copper dendrites, reducing burrs, and reducing the surface roughness of the copper foil. On the other hand, it is conducive to the uniformity and stability of the electrocrystallization and electrodeposition processes. At the same time, the anode part is connected to a DC power supply and a pulse power supply, and the pulse current applied by the pulse power supply is conducive to the refinement of the generated grains, optimizes the electrocrystallization process, and is conducive to reducing the surface roughness of the copper foil. Therefore, the copper foil prepared by the electrolytic copper foil equipment of the present application has low roughness and a smooth surface.

[0022] In a third aspect, the present application provides a copper foil, which is produced by the electrolytic copper foil preparation method of the above-mentioned application, or produced by the electrolytic copper foil equipment of the above-mentioned application.

[0023] The copper foil of the present application has low surface roughness, is uniformly smooth, has a uniform thickness with a small tolerance, and has few burrs. It also has high mechanical properties such as tensile strength, a low difference between the transverse elongation and the longitudinal elongation, and has ideal comprehensive performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] Figure 1 This is a schematic flow chart of the method for preparing electrolytic copper foil in Example 1 of the present application;

[0026] Figure 2 This is a pulse diagram of the unidirectional pulse power supply passing through the first anode plate 41 in Example 1 of the present application;

[0027] Figure 3 This is a pulse diagram of the bidirectional pulse power supply passing through the second anode plate 42 in Example 1 of the present application;

[0028] Figure 4 This is a pulse diagram of the bidirectional pulse power supply connected to the penultimate anode plate 43 in Example 1 of the present application;

[0029] Figure 5 is a schematic structural diagram of the liquid mixer in Example 1 of the present application;

[0030] Figure 6 Schematic diagram of the structure of the anode portion in Example 1 of the present application;

[0031] Figure 7 This is a schematic structural diagram of the electrolytic copper foil equipment of Example 1 of the present application;

[0032] Figure 8 This is a SEM diagram of the copper foil surface obtained in Comparative Example 1 of the present application;

[0033] Figure 9 This is a SEM diagram of the surface of the copper foil obtained in Example 1 of the present application;

[0034] Figure 10 This is a SEM diagram of the surface of the copper foil prepared in Comparative Example 2 of the present application;

[0035] Figure 11 This is a SEM diagram of the surface of the copper foil obtained in Example 2 of the present application;

[0036] Figure numerals: 1-electrolytic cell; 2-cathode part; 3-anode part; 4-anode plate; 41-first anode plate; 42-second anode plate; 43-second-to-last anode plate; 5-electrolyte container; 6-detection device; 7-ultrasonic device. DETAILED DESCRIPTION

[0037] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0038] In this application, the term "and / or" describes the relationship between associated objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0039] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items.

[0040] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0041] The weights of the relevant components mentioned in the examples of this application may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the examples of this application, it is within the scope disclosed in the examples of this application. Specifically, the mass in the examples of this application may be μg, mg, g, kg, etc., which are mass units known in the chemical industry.

[0042] The terms "first" and "second" are used solely for descriptive purposes to distinguish objects, such as substances, from one another and should not be understood to indicate or imply relative importance or to implicitly specify the quantity of the technical features being referred to. For example, without departing from the scope of the embodiments of this application, a first XX may also be referred to as a second XX, and similarly, a second XX may also be referred to as a first XX. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of such features.

[0043] The first aspect of the present application provides a method for preparing electrolytic copper foil. Figure 1 and Figure 7 The method for preparing the electrolytic copper foil in the embodiment of the present application includes the following steps:

[0044] S10: Detect the copper ion concentration C in the electrolyte 实 ;

[0045] S20: Set a copper ion concentration reference value C 参 , according to C 实 with C 参 The electrolyte is ultrasonically treated by applying the following ultrasonic wave:

[0046] When C 实 <C 参 When the first ultrasonic wave is applied;

[0047] When C 实 ≥C 参 When the second ultrasonic wave is applied;

[0048] The frequency of the first ultrasonic wave is higher than the frequency of the second ultrasonic wave;

[0049] S30: introducing the ultrasonically treated electrolyte into the electrolytic cell 1 to perform electrolytic reaction treatment to generate copper foil. In the electrolytic cell 1, direct current is applied to the cathode part 2, and direct current and pulse current are applied to the anode part 3.

[0050] The preparation method of the embodiment of the present application sets the ultrasonic frequency adaptively according to the copper ion concentration in the electrolyte, which greatly improves the targeted effect of ultrasonic treatment. 实 , when C 实 <C 参 When C is low, the copper ion concentration in the electrolyte is low, the copper ion migration rate is low, and the mass transfer efficiency of the electrolyte is low, so a higher frequency first ultrasonic wave needs to be applied; when ... 实 ≥C 参 When the copper ion concentration in the electrolyte is high, the copper ion migration rate is relatively high, so only the second ultrasonic wave of lower frequency needs to be applied. In this way, it is achieved that ultrasonic waves of different frequencies are applied according to different copper ion concentrations, so that the copper ion migration rate in the electrolyte is improved and remains stable, improves mass transfer efficiency, and is compatible with the consumption rate of the cathode portion 2. On the one hand, it reduces the concentration polarization phenomenon, is conducive to reducing copper dendrites, reduces burrs, and reduces the surface roughness of the copper foil obtained. On the other hand, it is conducive to electrocrystallization and electrodeposition processes being uniform and stable. At the same time, the preparation method passes direct current and pulse current in the anode portion 3, and continuous direct current makes copper ions more inclined to form larger and coarser grains, and pulse current makes copper ions more inclined to generate high-density, small, evenly distributed crystal nuclei, and reduces the growth of crystal nuclei. Therefore, introducing pulse current is conducive to the grain refinement generated, optimizes the electrocrystallization process, and electrodeposition is more uniform, which is conducive to reducing the surface roughness of the copper foil. Therefore, the preparation method of the embodiment of the present application improves the copper ion migration rate and the electrocrystallization process by optimizing the ultrasonic frequency and introducing pulse current, alleviates the phenomenon of coarse grains, makes the electrodeposition process more uniform, and the prepared copper foil has low roughness and a smooth surface.

[0051] In addition to the above-mentioned technical effect of reducing the roughness of copper foil, on the one hand, finer grains and uniform electrodeposition of copper foil are also conducive to uniform thickness distribution of the prepared copper foil, which is conducive to improving the mechanical properties of the copper foil such as tensile strength. On the other hand, in the existing electrolytic preparation method, copper ions are first reduced to cuprous ions and then further reduced to copper at the cathode. However, cuprous ions may come into contact with oxygen generated at the anode in the electrolyte, causing Cu + The disproportionation reaction generates cuprous oxide, which is deposited together with copper, causing the problem of Cu2O inclusion defects in the copper foil. The preparation method of the present application improves the migration rate of copper ions and, combined with the pulse current, greatly reduces the Cu + The disproportionation reaction reduces Cu2O inclusion defects. Furthermore, alleviating concentration polarization helps maintain an appropriate anode current density, eliminating the need to increase cell voltage to maintain reaction rate. Furthermore, the pulsed current allows for an off-period, both of which contribute to lower energy consumption and costs. Therefore, regulating ultrasound and introducing pulsed current according to copper ion concentration can improve the overall preparation process and copper foil quality.

[0052] In the above description Figure 7 This is merely a reference example, intended to illustrate the roles of the electrolytic cell 1, cathode portion 2, and anode portion 3 in the electrolytic reaction process, and does not constitute a limitation on the shape, size, or relative position of these three components. The cathode portion 2 and anode portion 3 in the electrolytic copper foil preparation method can be static, with the copper foil removed after the electrolytic reaction is complete, or dynamic, such as in the commonly used industrial production method where the cathode portion 2 continuously rotates to continuously produce copper foil. The copper foil is continuously deposited and peeled off from the cathode portion 2. Therefore, the cathode portion 2 is generally continuous, making it difficult to set different currents. Generally, only direct current is passed through it, while pulsed current is generally passed through the anode portion 3.

[0053] Step S10 is a step of detecting the copper ion concentration in the electrolyte. In the embodiment, the electrolyte can be an electrolyte formed by a soluble copper salt such as copper sulfate, and the copper ion concentration can be detected by titration, spectrophotometry, etc.; for the dynamic preparation process, continuous or semi-continuous online monitoring can be achieved by using electrochemical sensors or optical probes, etc., in conjunction with automatic sampling and data processing. When the copper ion concentration in the electrolyte changes, the ultrasonic parameters can be adjusted in time, such as Figure 1 As shown in "Electrolyte Supply" and "Copper Ion Concentration Detection" in the embodiment, the copper ion concentration in the electrolyte can be monitored and fed back online every 30 seconds.

[0054] Step S20 is the step of applying ultrasonic waves. This step S20 and the above step S10 can form a dynamic process. The overall principle is to reduce the ultrasonic frequency when the copper ion concentration is high and increase the ultrasonic frequency when the copper ion concentration is low. Figure 1 The "low concentration" and "high concentration" processes are shown in FIG. In this embodiment, the frequency of the ultrasonic wave can be set to 20 to 50 kHz, and the amplitude of the ultrasonic wave can be less than 10 μm. Applying ultrasonic waves to the electrolyte makes the electrolyte a medium for ultrasonic transmission. These high-frequency micro-vibrations, tens of thousands of times per second, cause the electrolyte to produce high-frequency micro-vibrations similar to water ripples. This helps improve the electrolyte's mass transfer efficiency, increases the copper ion migration rate, matches the consumption rate of the cathode portion 2, and alleviates concentration polarization.

[0055] To this end, first set a copper ion concentration reference value C 参 , this parameter needs to be set with comprehensive reference to copper foil production rate, thickness requirements, and current parameters. In some embodiments, C 参 It can be 78-93 g / L, including but not limited to any value of 78 g / L, 81 g / L, 85 g / L, 89 g / L, 93 g / L or any range between two values, and 85 g / L can be selected as the concentration of C. 参It is beneficial to improve the adaptability of ultrasonic regulation and copper ion concentration, so that the copper ion migration rate is high and stable, matching the copper ion consumption rate of the cathode part 2, which is beneficial to reduce the concentration polarization phenomenon and facilitate the uniform and stable electrocrystallization and electrodeposition process. 实 <C 参 When the frequency of the first ultrasonic wave applied is 38-44kHz, when C 实 ≥C 参 When the second ultrasonic wave is applied, the frequency is 23-29kHz. These parameters are conducive to further improving the adaptability of ultrasonic wave and copper ion concentration, alleviating concentration polarization phenomenon, reducing the roughness of copper foil, and inhibiting Cu + disproportionation reaction to reduce energy consumption.

[0056] In the embodiment, organic additives such as polyethylene glycol (PEG) and polyethyleneimine (PEI) are often added to the electrolyte of the electrolytic preparation of copper foil, especially the industrial electroforming process, to refine the grains, improve mechanical properties, surface smoothness, glossiness and uniformity. However, as the electrolysis reaction proceeds, these organic additives will gradually adsorb on the electrodes, especially on the cathode part 2, which will affect the reduction of copper ions, require shutdown for cleaning, and lead to increased energy consumption. When ultrasound is applied to the electrolyte, its high-frequency, micro-amplitude vibration will generate tensile stress in the electrolyte and form a local negative pressure, causing the gas originally dissolved in the electrolyte to be supersaturated and escaping a large number of micron-sized microbubbles. The diameter of the microbubbles is between 50 and 500 μm, which can continuously clean the electrodes, remove the adsorbed organic matter, keep the electrodes, especially the cathode part 2, clean, and more conducive to the deposition of copper.

[0057] Step S30 is a step of performing an electrolytic reaction, such as Figure 7 As shown, the ultrasonically treated electrolyte is introduced into the electrolytic cell 1. After power is applied, an oxidation-reduction reaction occurs in the electrolytic cell 1. A direct current is applied to the cathode portion 2, typically connected to the negative electrode of the power supply. The reaction that occurs is that copper ions gain electrons and are reduced to copper. A direct current and pulsed current are applied to the anode portion 3, typically connected to the positive electrode of the power supply. The reaction that occurs is that water loses electrons and is oxidized to form oxygen and hydrogen ions. The magnitude of the direct current can be set based on parameters such as the production rate and thickness of the copper foil. If the pulse current is in the same direction as the direct current applied to the anode portion 3 (hereinafter referred to as a positive pulse), the reaction in the electrolyte is the same, and the copper ions are more likely to form nuclei, reducing growth and more conducive to the formation of refined copper grains. If the pulse current is in the opposite direction to the direct current applied to the anode portion 3 (hereinafter referred to as a negative pulse), the copper deposited in the corresponding cathode portion 2 is oxidized and dissolved into the electrolyte, generally used to dissolve the bumps on the copper foil. After the electrolytic reaction treatment in step S30, the copper ions can be deposited on the cathode portion 2 to prepare the copper foil.

[0058] During the electrolysis reaction in electrolytic cell 1, copper ions near cathode portion 2 are rapidly consumed. If the migration rate of copper ions in the electrolyte in electrolytic cell 1 is insufficient, concentration polarization can easily occur. Therefore, step S30 introduces the ultrasonically treated electrolyte into electrolytic cell 1. Ideally, ultrasonic waves are continuously propagated in the electrolyte introduced into electrolytic cell 1. High-frequency micro-vibrations cause the electrolyte to flow at high frequencies, which helps to increase the migration rate of copper ions, reduce concentration polarization, and facilitate electrode cleaning.

[0059] Even if pulse current is introduced in the prior art, the relevant parameters of the pulse current cannot be well adapted to other parameters in production, or cannot be dynamically adjusted according to the electrolysis reaction process, resulting in poor results of introducing the pulse current. However, the present application simultaneously introduces ultrasound and pulse current, not only adapting the ultrasound frequency to the copper ion concentration, but also further adapting the pulse current frequency to the ultrasound frequency. The pulse current frequency can be 0.01 to 0.08 times the ultrasound frequency, thus further adapting the ultrasound's effect of improving mass transfer efficiency and the pulse current's effect of improving electrocrystallization. The synergistic effect improves and alleviates the problem of coarse grains and reduces the roughness of the copper foil.

[0060] Moreover, adapting the frequency of the pulse current to the frequency of the ultrasound wave also, to a certain extent, adapts the frequency of the pulse current to the copper ion concentration. When the copper ion concentration is low, high-frequency ultrasound waves are used, and relatively speaking, low-frequency pulse currents are selected. When the copper ion concentration is high, low-frequency ultrasound waves are used, and relatively speaking, high-frequency pulse currents are selected. This is because the copper ion concentration in the electrolyte also affects the tendency of nucleation and growth. When the copper ion concentration in the electrolyte is low, the electrolytic reaction is more inclined to form crystal nuclei rather than to grow, and a large number of copper spots will be formed in the copper foil. At this time, applying low-frequency pulses is beneficial to maintaining normal growth of the copper foil while refining the grains. When the copper ion concentration in the electrolyte is high, the electrolytic reaction is more inclined to grow rather than to form crystal nuclei, and a large number of coarse crystals will be formed. At this time, applying high-frequency pulses is beneficial to refining the grains.

[0061] Therefore, by adapting the frequency of the pulse current to the ultrasonic frequency, dynamic adjustment of the two parameters to the copper ion concentration is achieved, which is conducive to further synergistic optimization of mass transfer efficiency and electrocrystallization process, grain refinement, further reducing the surface roughness of the copper foil, uniform and stable electrodeposition process, and further improving thickness uniformity, increasing tensile strength, reducing Cu2O inclusion defects, and reducing energy consumption.

[0062] In addition to being adapted to the frequency of the applied ultrasonic wave, different types and frequencies of pulse currents can also be used in different areas of the anode portion 3. Figure 6 、 Figure 7As shown, the anode portion 3 may include several parallel parts, one of which is pulsed with current and the remaining part is direct current, so as to reduce the influence between the parts. Moreover, when the copper foil is produced dynamically and continuously, the pulse current can be applied to the starting area and the ending area of ​​the anode portion 3 (the starting area and the ending area are collectively referred to as the head and tail areas) along the production direction of the copper foil, wherein the high-frequency pulse current is applied to the starting area, which is conducive to the rapid formation of a large number of crystal nuclei and the formation of a dense bottom layer, and the bidirectional low-frequency pulse current is applied to the ending area, which is conducive to normal deposition while dissolving the protrusions on the surface of the copper foil. In this way, applying different pulse currents to the head and tail areas of the anode portion 3 is conducive to refining the grains, reducing the surface roughness, and reducing the thickness fluctuation of the copper foil and reducing the thickness tolerance.

[0063] In a further embodiment where different pulse currents are applied to the head and tail regions, Figure 6 、 Figure 7 As shown, the cathode part 2 is a roller structure, and the anode part 3 encloses the working surface of the cathode part 2. The anode part 3 includes a plurality of anode plates 4, each of which is arranged in sequence and connected in parallel with each other; the cathode part 2 rotates relative to the anode part 3, and along the direction of rotation of the cathode part 2, the cathode part 2 passes through each anode plate 4 in sequence, wherein the first anode plate 41, the second anode plate 42 and the second to last anode plate 43 are passed through a pulse current, and the remaining anode plates 4 are passed through a direct current for electrolytic reaction treatment. Among them, the improvement effect of selecting the second to last anode plate 43 as the anode plate 4 for passing a pulse current in the slot area is more ideal. The main reason is that if the area passing the pulse current is too far away from the slot position, the effect of dissolving the bumps on the copper foil surface will be weakened, and will continue to be produced on the subsequent copper foil. If it is too close to the slot position, the copper powder on the copper foil will fall off due to the dissolution effect.

[0064] In a further embodiment, the pulse current and the ultrasonic frequency can be further adapted to further optimize the electrocrystallization process. Since different grain orientations of copper have different hardness and deformation capabilities during crystallization, such as <111> The direction is usually the hardest, <100> The direction is relatively soft. If the orientation is chaotic, the strength and ductility of different areas of the copper foil will vary greatly, resulting in unstable overall mechanical properties and usually lower than the ideal orientation-dominated situation. Of course, it will also lead to problems such as inconsistent grain size, increased roughness, and a large gap between transverse tensile performance and longitudinal tensile performance. Even if the existing technology introduces pulse current, it often blindly sets fixed parameters, and the effect of guiding grain orientation is still limited. In a further embodiment of the present application, the pulse current is adapted to ultrasound, and dynamically adjusted according to the copper ion concentration, which can significantly improve the consistency of grain orientation and improve the performance of copper foil. The following will be described separately from the two aspects of the frequency of the pulse current and the type of pulse current:

[0065] [Frequency of pulse current]

[0066] First, the frequency of the pulse current. As stated above, the frequency of the pulse current can be 0.01 to 0.08 times the frequency of the ultrasonic wave. In some embodiments, when C 实 <C 参 When the first anode plate 41 is passed through, the frequency of the pulse current is 0.03 to 0.035 times the first ultrasonic frequency. In some embodiments, the frequency of the pulse current passed through the second anode plate 42 is 0.041 to 0.044 times the first ultrasonic frequency. The first anode plate 41 and the second anode plate 42 are both in the early stage of copper foil preparation and electroplating. These high-frequency pulse currents are adapted to the ultrasonic frequency, which is conducive to the rapid formation of a large number of crystal nuclei and the formation of a dense bottom layer, which is conducive to the subsequent passage of direct current to allow the copper foil to further grow on this basis. In some embodiments, the frequency of the pulse current passed through the penultimate anode plate 43 is 0.01 to 0.015 times the first ultrasonic frequency. In the end area of ​​the electrolytic copper foil preparation, these relatively low-frequency pulse currents are adapted to the ultrasonic frequency, which is conducive to the normal growth of the copper foil while refining the grains, or further coordinating with the direction of the pulse current to dissolve the bumps on the surface of the copper foil.

[0067] In some embodiments, when C 实 ≥C 参 When the first anode plate 41 passes through a pulse current with a frequency of 0.07 to 0.08 times the second ultrasonic frequency. In some embodiments, the second anode plate 42 passes through a pulse current with a frequency of 0.07 to 0.08 times the second ultrasonic frequency. In some embodiments, the second to last anode plate 43 passes through a pulse current with a frequency of 0.03 to 0.04 times the second ultrasonic frequency. These pulse current frequency multiple parameters are similar to the effects of the above-mentioned ultrasonic frequency adaptation, except that in C 实 ≥C 参 When the copper ion concentration is too high, the copper ion concentration is too high compared to C 实 <C 参 The frequency of the pulse current set during operation should be adjusted accordingly to the multiple of the ultrasonic frequency.

[0068] [Type of pulse current]

[0069] Secondly, the type of pulse current. In some embodiments, the pulse current of the first anode plate 41 is a unidirectional pulse current; the unidirectional pulse current is also a positive pulse current, which has the same direction as the DC current of the remaining anode plates 4. At the initial stage of copper foil electrodeposition, applying a high-frequency unidirectional pulse current is conducive to the rapid formation of a large number of crystal nuclei and the formation of a dense bottom layer. The unidirectional pulse current jumps from the baseline to the peak instantaneously, and can be a rectangular wave, which can be referred to Figure 2In the embodiment, the duty cycle of the unidirectional pulse current is 0.97-0.99, that is, in each cycle, the power-on time accounts for 0.97-0.99, the power-on time is very long and the off period is very short, so a large number of crystal nuclei are formed quickly.

[0070] In some embodiments, the peak current of the unidirectional pulse current is the total current value of the electrolytic reaction divided by the total number of anode plates 4. This allows the current value of the unidirectional pulse current to be compatible with the direct current flowing through the remaining anode plates 4, making the electrodeposition process more uniform. In some embodiments, along the direction of rotation of the cathode portion 2, the length of the anode portion 3 is from the first anode plate 41 to the last anode plate 4, which is considered to be from 0% to 100% of the length. The first anode plate 41 is positioned in the region of 0% to 5% of the length of the anode portion 3. By defining a specific region along the entire length of the anode portion 3, the region where the first anode plate 41 is positioned can be better understood, which is beneficial for setting a rapid nucleation zone at the initial stage of the electrolytic reaction.

[0071] In the embodiment, after the frequency of the unidirectional pulse current is set according to the ultrasonic frequency, the current-on duration can be determined according to pulse frequency = copper foil production line speed / (length of the first anode plate 41 * current-on duration / duty cycle).

[0072] In some embodiments, the pulse current passed through the second anode plate 42 is a first bidirectional pulse current, including a first positive current and a first negative current to form a cycle; the bidirectional pulse passing through the second anode plate 42 is conducive to rapidly forming a large number of crystal nuclei while refining the grains, especially dissolving some larger grains and further refining them, and cooperating with the first anode plate 41 to form a dense bottom layer in the early stage of the electrolysis reaction, thereby improving the uniformity of the bottom layer. In the embodiment, the first positive current and the first negative current can both be rectangular waves, such as Figure 3 As shown, the ratio of the on-time of the first positive current to the on-time of the first negative current is (2-4):1. In some embodiments, the ratio of the peak current of the first positive current to the peak current of the first negative current is (90-100):1. In these positive and negative current on-time ratios and peak current ratios, the positive current is dominant, and the negative current is supplementary, so that the cathode portion 2 corresponding to the second anode plate 42 mainly forms crystal nuclei, supplemented by the dissolution of coarse grains.

[0073] In some embodiments, along the direction of rotation of the cathode portion 2, the length of the anode portion 3 is from the first anode plate 41 to the last anode plate 4, which is considered to be from 0% to 100% of the length. The second anode plate 42 is arranged in an area between 5% and 10% of the length of the anode portion 3. By defining a specific area along the entire length of the anode portion 3, the area where the second anode plate 42 is arranged can be better understood, which is conducive to setting a rapid nucleation zone in the initial stage of the electrolysis reaction.

[0074] In an embodiment, after the frequency of the first bidirectional pulse current is set according to the ultrasonic frequency, the duration of the positive and negative current being turned on can be determined according to the formula: pulse frequency = copper foil production line speed / (length of the second anode plate 42 * (forward current on time + negative current on time) / duty cycle).

[0075] Since it is difficult to achieve a high frequency of bidirectional pulse current, in some embodiments, the first bidirectional pulse current is provided by 6 groups of power supplies, each of which applies a bidirectional pulse current with the same parameters in turn, and the duty cycle of the current applied by each power supply is ≤12%. Each group of power supplies can provide a group of bidirectional pulse currents, so that the 6 groups of power supplies alternately relay in turn, starting from the first group of power supplies to the last group of power supplies. After completing one round, the first group of power supplies continues to start, so that each group of power supplies has a longer off period, and finally, with the cooperation of multiple groups of power supplies, a high-frequency bidirectional pulse current is passed to the second anode plate 42. In addition, since the bidirectional pulse current parameters applied by each power supply are the same, the average current remains unchanged during the alternating operation, which is beneficial to improving the stability of the first bidirectional pulse and the uniformity of the electrodeposition. In the embodiment, it can also be provided by 5, 7, or 8 groups of power supplies.

[0076] In the embodiment, the duty cycle and off-time design of the first bidirectional pulse current can refer to the following method. First, the frequency of the first bidirectional pulse current is set according to the ultrasonic frequency. For example, when the frequency of the first bidirectional pulse current is 1.936kHz, the period and the frequency are reciprocal of each other, and a period is calculated to be approximately 516.5μs. Taking 6 groups of power supplies as an example, for each group of power supplies, the maximum on-time of each group is 1 / 6 of the total period, which is approximately 86.1μs, that is, the positive pulse width (pulse width refers to the on-time within a period) plus the negative pulse width of each group of power supplies is approximately 86.1μs, that is, the maximum duty cycle of each group of power supplies is 1 / 6, which is approximately 16.7%. In this way, there is no off-time for the entire first bidirectional pulse current, that is, each group of power supplies can be seamlessly connected to the previous group of power supplies, but this is difficult to achieve in reality. Therefore, the duty cycle of each group of power supplies can be further set to ≤12%, and the maximum positive pulse width plus negative pulse width of each group of power supplies is 516.5*12%, which is approximately 62μs. As shown in the embodiment, the positive pulse width of each group of power supplies is designed to be 30μs, and the negative pulse width is designed to be 15μs. In a total cycle, the turn-on time of each group of power supplies is 45μs, and the duty cycle is 45÷516.5, which is approximately 8.7%. The power supplies of each group alternate in sequence to eventually form a first bidirectional pulse current. The total duty cycle is approximately 8.7%*6, which is approximately 52.2%.

[0077] In some embodiments, the pulse current passed through the penultimate anode plate 43 is a second bidirectional pulse current, including a second positive current and a second negative current forming a cycle; the second positive current and the second negative current can both be rectangular waves, such as Figure 4As shown. The ratio of the time when the second forward current is turned on to the time when the second negative current is turned on is (10-20):1, that is, if there is no off period, the duty cycle of the second forward current is 0.909-0.952. In some embodiments, the ratio of the peak current of the second forward current to the second negative current is (95-100):1. Under these parameters, the second forward current is the main current and the second negative current is the auxiliary current. Due to the coordinated optimization of the aforementioned ultrasonic treatment and the pulse current, there are very few protrusions on the surface of the copper foil in the final stage of preparation, and the maximum is only 0.1-0.3μm. Therefore, the above parameters make the second pulse current mainly beneficial to grain refinement, and secondly beneficial to dissolving the protrusions on the surface of the copper foil, which is beneficial to more uniform electroplating. In some embodiments, the duty cycle of the second bidirectional pulse current is 98% to 100%. As stated in the frequency of the pulse current above, in the end area of ​​the electrolytic preparation of copper foil, the second bidirectional pulse current can be a low-frequency pulse current, so a higher duty cycle can be achieved. Ideally, the duty cycle reaches 100% without an off period.

[0078] In an embodiment, after the frequency of the second bidirectional pulse current is set according to the ultrasonic frequency, the duration of the positive and negative current being turned on can be determined according to the formula: pulse frequency = copper foil production line speed / (length of the second-to-last anode plate 43 * (forward current on time + negative current on time) / duty cycle).

[0079] In a further embodiment, the duration of the second positive current and the second negative current in the second bidirectional pulse current can be adapted to the concentration of copper ions. 实 <C 参 , when the first ultrasonic wave is applied, the duty cycle of the second forward current is 0.915~0.935. 实 ≥C 参 When the second ultrasonic wave is applied, the duty cycle of the second forward current is 0.935~0.952, which is beneficial to further improve the compatibility of the second bidirectional pulse current with the copper ion concentration, optimize the process of electrocrystallization and electrodeposition, balance the effects of grain refinement and dissolution of bumps in the final stage, and help reduce the roughness of the copper foil surface.

[0080] In the embodiment, after combining the above parameters, the parameter settings can refer to the following Table 1:

[0081] Table 1

[0082]

[0083]

[0084] Referring to the above method, the embodiment of the present application creatively adapts the frequency of the pulse current to the ultrasonic wave. In addition to improving concentration polarization and refining grains, it further applies different types of pulse currents in different regions to further optimize the process of electrocrystallization and electrodeposition, significantly improve the consistency of the grain orientation of the copper foil, and further improve the performance of the copper foil.

[0085] After completing step S30, the raw copper foil has been produced. The raw copper foil may be further processed, including but not limited to winding, anti-oxidation, annealing to optimize mechanical properties, cutting, burr control, etc., to obtain the desired copper foil.

[0086] The second aspect of the embodiment of the present application provides an electrolytic copper foil device, such as Figure 5 、 Figure 6 、 Figure 7 As shown, the electrolytic copper foil equipment includes:

[0087] The cathode portion 2 is connected to a DC power supply;

[0088] Anode part 3, connected to DC power supply and pulse power supply;

[0089] An electrolytic cell 1, a cathode portion 2 and an anode portion 3 are disposed in the electrolytic cell 1;

[0090] an electrolyte container 5, connected to the electrolytic cell 1;

[0091] Detection device 6, used to detect the copper ion concentration in the electrolyte in the cavity of the electrolyte container 5;

[0092] The ultrasonic device 7 is used to apply ultrasonic waves to the electrolyte.

[0093] The detection device 6 of the electrolytic copper foil equipment of the embodiment of the present application can detect the copper ion concentration in the electrolyte in the cavity. According to the level of the detection result of the detection device 6, the ultrasonic device 7 can apply frequency-adapted ultrasonic waves to the electrolyte, so that the migration rate of the copper ions in the electrolyte is increased and maintained stable, thereby improving the mass transfer efficiency and adapting to the consumption rate of the cathode part 2. On the one hand, it reduces the concentration polarization phenomenon, which is conducive to reducing copper dendrites, reducing burrs, and reducing the surface roughness of the copper foil. On the other hand, it is conducive to uniform and stable electrocrystallization and electrodeposition processes. At the same time, the anode part 3 is connected to a DC power supply and a pulse power supply. The pulse current applied by the pulse power supply is conducive to the refinement of the generated grains, optimizes the electrocrystallization process, and is conducive to reducing the surface roughness of the copper foil. Therefore, the copper foil prepared by the electrolytic copper foil equipment of the embodiment of the present application has low roughness and a smooth surface.

[0094] Furthermore, the copper foil produced by the electrolytic copper foil equipment of the embodiment of the present application also has the advantages of uniform thickness distribution, ideal mechanical properties such as tensile strength, and few Cu2O inclusion defects, and the energy consumption of the equipment during production is low. Figure 5 、 Figure 6 、 Figure 7 These are only examples for reference and do not constitute any limitation on the shapes, sizes, or relative positions of these components and devices.

[0095] In an embodiment, the detection device 6 may include components such as an electrochemical sensor or an optical probe. The detection device 6 may be disposed in the cavity of the electrolyte container 5. The cavity of the electrolyte container 5 may also include a mechanical stirring device. The ultrasonic device 7 may be disposed in the cavity of the electrolyte container 5, or on the container wall of the electrolyte container 5, or in a pipe connecting the electrolyte container 5 and the electrolytic cell 1, or in the electrolytic cell 1. In an embodiment, a hole may be opened in the electrolyte container 5, and the ultrasonic device 7 may be placed in the cavity of the electrolyte container 5. After the ultrasonic wave acts on the electrolyte therein, the ultrasonic wave will be transmitted to the electrolytic cell 1 synchronously with the electrolyte, causing the electrolyte in the cell to vibrate.

[0096] The cathode portion 2 is connected to the negative electrode of the DC power supply. Part of the anode portion 3 is connected to the positive electrode of the DC power supply, and the remaining area is connected to the pulse power supply. The anode portion 3 may include multiple anode plates 4 connected in parallel, wherein some anode plates 4 are connected to the positive electrode of the DC power supply and the remaining anode plates 4 are connected to the pulse power supply to reduce the mutual influence of current.

[0097] In a further embodiment, Figure 6 、 Figure 7 As shown, the cathode portion 2 is a drum structure, and the anode portion 3 encloses the working surface of the cathode portion 2. The anode portion 3 includes a plurality of anode plates 4, each of which is arranged in sequence and connected in parallel. The cathode portion 2 rotates relative to the anode portion 3. Along the direction of rotation of the cathode portion 2, the cathode portion 2 passes through each anode plate 4 in sequence. Among them, the first anode plate 41, the second anode plate 42, and the second-to-last anode plate 43 are connected to a pulse current power supply, and the remaining anode plates 4 are connected to a DC power supply. This structure allows the cathode portion 2 to continuously rotate and sequentially pass through each anode plate 4 to deposit copper foil, which is more conducive to the continuous and stable production of copper foil. In addition, the specific first anode plate 41, the second anode plate 42, and the second-to-last anode plate 43 in the anode portion 3 are connected to a pulse current power supply, and the remaining anode plates 4 are connected to a DC power supply. This facilitates the rapid formation of a large number of crystal nuclei in the starting area of ​​copper deposition, forming a dense bottom layer, and normal deposition in the ending area while dissolving the protrusions on the copper foil surface, which is conducive to refining the grains, reducing surface roughness, and reducing the thickness fluctuation of the copper foil and reducing the thickness tolerance.

[0098] In the embodiment, the radius of the roller structure of the cathode part 2 can be 2 to 3 meters, and the roller structure can be set on the roller surface of a roller, such as Figure 7As shown, the roller can rotate axially, and the roller surface can be annular. As the roller rotates, the cathode portion 2 rotates accordingly. In the embodiment, the distance between the cathode portion 2 and the anode portion 3 can be 0.8 to 1.2 cm. In the embodiment, the anode portions 3 can be formed by sequentially splicing the anode plates 4, and the distance between adjacent anode plates 4 can be 0.05 to 0.1 cm.

[0099] The parameters of the DC power supply and the pulse power supply can refer to the power supply parameters in the electrolytic copper foil preparation method above. The electrolytic copper foil equipment of the present application embodiment may also include but is not limited to a temperature monitoring device, a pH monitoring device, an electrolyte reflux device, a transmission device, a winding device, and other devices.

[0100] A third aspect of the embodiments of the present application provides a copper foil, which is produced by the electrolytic copper foil preparation method of the above embodiments of the present application, or produced by the electrolytic copper foil equipment of the above embodiments of the present application.

[0101] The copper foil of the embodiment of the present application has low surface roughness, is uniformly smooth, has a small thickness tolerance, and has few burrs. It also has high mechanical properties such as tensile strength, a low difference between the lateral elongation and the longitudinal elongation, and has ideal comprehensive performance.

[0102] According to testing, in some embodiments, the Ra value of the copper foil is ≤1.4 μm. In some embodiments, the tensile strength of the copper foil is ≥20 MPa. In some embodiments, the difference between the transverse elongation and the longitudinal elongation of the copper foil is ≤1%.

[0103] The following describes the details in conjunction with specific embodiments.

[0104] Example 1

[0105] This embodiment provides a method for preparing electrolytic copper foil, an electrolytic copper foil device, and copper foil. The preparation method is as follows: Figure 1 As shown, it includes steps S1 to S3:

[0106] S1: If Figure 5 As shown, the electrolyte is stirred in the electrolyte container 5, and the electrolyte is a copper sulfate solution. The copper sulfate solution in the electrolyte container 5 is detected by the detection device 6, and the result is 82.2 g / L;

[0107] S2: A reference copper ion concentration is preset to be 85 g / L, 82.2 g / L is less than 85 g / L, and ultrasonic waves are applied to the copper sulfate solution in the electrolyte container 5 by the ultrasonic device 7 at a frequency of 41 kHz. The electrolyte container 5 is connected to the electrolytic cell 1;

[0108] S3: The ultrasonically treated electrolyte is introduced into the electrolytic cell 1 for electrolytic reaction treatment, such as Figure 6 、 Figure 7As shown, the cathode part 2 is a drum structure, and the anode part 3 encloses the working surface of the cathode part 2. The anode part 3 includes a plurality of parallel rectangular anode plates 4, and the anode plates 4 are arranged in sequence. The length of each anode plate 4 is 234.6 mm. The length here refers to the length of the side of an anode plate 4 along the direction of rotation of the cathode part 2, so as to avoid differences in understanding caused by different descriptions of the length and width due to the shape of the anode plate 4; the cathode part 2 rotates relative to the anode part 3, and along the direction of rotation of the cathode part 2, the cathode part 2 passes through each anode plate 4 in sequence, wherein the first anode plate 41, the second anode plate 42 and the penultimate anode plate 43 are connected to a pulse current power supply, and the remaining anode plates 4 are connected to a DC power supply.

[0109] The theoretical thickness of the copper foil produced is 35 μm, the production line speed is 2.68 m / min, the total production current is 50 kA, and other specific parameters are shown in Table 2 below.

[0110] Table 2

[0111]

[0112] Example 2

[0113] The only difference between Example 2 and Example 1 is that the copper ion concentration is measured to be 87.5 g / L, and then the parameters are adjusted as shown in Table 3 below, and the other steps remain unchanged.

[0114] Table 3

[0115]

[0116] Comparative Example 1

[0117] The only difference between this comparative example and Example 1 is that no ultrasonic wave is provided, only mechanical stirring is used, and no pulse current is applied to some anode plates 4, but direct current is applied uniformly. All other aspects are the same.

[0118] Comparative Example 2

[0119] The only difference between this comparative example and Example 2 is that no ultrasonic wave is provided, only mechanical stirring is used, and no pulse current is applied to some anode plates 4, but direct current is applied uniformly. All other aspects are the same.

[0120] Process comparison and performance testing

[0121] 1. Comparison between Example 1 and Comparative Example 1

[0122] Example 1 was produced five times, which were recorded as experimental group 1 to experimental group 5 respectively. Comparative Example 1 was produced five times, which were recorded as blank group 1 to blank group 5 respectively. The energy consumption comparison results are shown in Table 4 below:

[0123] Table 4

[0124]

[0125] As can be seen from Table 4, the energy consumption of Example 1 and Comparative Example 1 in producing the same product is only 90.13% of that of the blank group, which greatly reduces the production cost.

[0126] The samples produced five times in Example 1 were recorded as experimental groups 1 to experimental groups 5, and the samples produced five times in Comparative Example 1 were recorded as blank groups 1 to blank groups 5. The performance test comparison results are shown in Table 5 below:

[0127] Table 5

[0128]

[0129] It can be seen from Table 5 that Example 1 has a lower Ra value than Comparative Example 1, lower roughness, and a more uniform surface. Figure 8 SEM images of the copper foil surface of Comparative Example 1 and Figure 9 SEM images of the copper foil surface in Example 1 also show more uniform and regular peaks, indicating more uniform electrodeposition. Furthermore, the horizontal and vertical variations in high-temperature elongation shown in Table 5 are smaller, further demonstrating the ideal electrocrystallization process and consistent grain orientation from a macroscopic perspective.

[0130] 2. Comparison between Example 2 and Comparative Example 2

[0131] Example 2 was produced five times, which were recorded as experimental group 1 to experimental group 5 respectively. Comparative Example 2 was produced five times, which were recorded as blank group 1 to blank group 5 respectively. The energy consumption comparison results are shown in Table 6 below:

[0132] Table 6

[0133]

[0134] As can be seen from Table 6, the energy consumption of Example 2 and Comparative Example 2 in producing the same product is only 87.13% of that of the blank group, which greatly reduces the production cost.

[0135] The samples produced five times in Example 2 were recorded as experimental group 1 to experimental group 5, and the samples produced five times in Comparative Example 2 were recorded as blank group 1 to blank group 5. The performance test comparison results are shown in Table 7 below:

[0136] Table 7

[0137]

[0138]

[0139] It can be seen from Table 7 that Example 2 has a lower Ra value than Comparative Example 2, a lower roughness, and a more uniform surface. Figure 10SEM images of the copper foil surface of Comparative Example 1 and Figure 11 SEM images of the copper foil surface in Example 1 also show that the peaks in Example 2 are more uniform and regular, indicating more uniform electrodeposition. Furthermore, the horizontal and vertical differences in high-temperature elongation shown in Table 7 are smaller, further demonstrating the ideal electrocrystallization process and consistent grain orientation from a macroscopic perspective.

[0140] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for preparing electrolytic copper foil, characterized in that: The steps include: Detect the copper ion concentration C in the electrolyte 实 ; Set a copper ion concentration reference value C 参 , according to the C 实 With the C 参 The electrolyte is subjected to ultrasonic treatment by applying the following ultrasonic wave: When C 实 <C 参 When the first ultrasonic wave is applied; When C 实 ≥C 参 When the second ultrasonic wave is applied; The frequency of the first ultrasonic wave is higher than the frequency of the second ultrasonic wave; The ultrasonically treated electrolyte is introduced into an electrolytic cell (1) for electrolytic reaction to generate copper foil. In the electrolytic cell (1), a direct current is passed through the cathode part (2) and a direct current and a pulse current are passed through the anode part (3).

2. The method for preparing electrolytic copper foil according to claim 1, wherein: The C 参 78~93g / L; and / or, the frequency of the first ultrasonic wave is 38 to 44 kHz; and / or, the frequency of the second ultrasonic wave is 23 to 29 kHz; And / or, the frequency of the pulse current is 0.01 to 0.08 times the frequency of the ultrasonic wave.

3. The method for preparing electrolytic copper foil according to claim 1 or 2, characterized in that: The cathode part (2) is a roller structure, the anode part (3) surrounds the working surface of the cathode part (2), and the anode part (3) includes a plurality of anode plates (4), and the anode plates (4) are arranged in sequence and connected in parallel. The cathode part (2) rotates relative to the anode part (3), and along the direction of rotation of the cathode part (2), the cathode part (2) passes through each of the anode plates (4) in sequence, wherein the first anode plate (41), the second anode plate (42) and the penultimate anode plate (43) are passed through the pulse current, and the remaining anode plates (4) are passed through direct current to perform the electrolytic reaction treatment.

4. The method for preparing electrolytic copper foil according to claim 3, wherein: When the C 实 <C 参 hour, The frequency of the pulse current passed through the first anode plate (41) is 0.03 to 0.035 times the frequency of the first ultrasonic wave; and / or, the frequency of the pulse current passed through the second anode plate (42) is 0.041 to 0.044 times the frequency of the first ultrasonic wave; and / or, the frequency of the pulse current passed through the penultimate anode plate (43) is 0.01 to 0.015 times the frequency of the first ultrasonic wave; Alternatively, when the C 实 ≥C 参 hour, The frequency of the pulse current passed through the first anode plate (41) is 0.07 to 0.08 times the frequency of the second ultrasonic wave; and / or, the frequency of the pulse current passed through the second anode plate (42) is 0.07 to 0.08 times the frequency of the second ultrasonic wave; And / or, the frequency of the pulse current passed through the penultimate anode plate (43) is 0.03 to 0.04 times the second ultrasonic frequency.

5. The method for preparing electrolytic copper foil according to claim 3, wherein: The pulse current passed through the first anode plate (41) is a unidirectional pulse current; wherein, The duty cycle of the unidirectional pulse current is 0.97 to 0.99; And / or, the peak current of the unidirectional pulse current is the total current value of the electrolytic reaction treatment divided by the total number of the anode plates (4); And / or, along the direction of rotation of the cathode part (2), the length from the first anode plate (41) to the last anode plate (4) is the length of the anode part (3), and the first anode plate (41) is arranged in the area of ​​0% to 5% of the length of the anode part (3).

6. The method for preparing electrolytic copper foil according to claim 3, wherein: The pulse current passed through the second anode plate (42) is a first bidirectional pulse current, which includes a first positive current and a first negative current to form a cycle; wherein, The ratio of the time during which the first positive current is turned on to the time during which the first negative current is turned on is (2-4):1; And / or, a ratio of a peak current of the first forward current to a peak current of the first negative current is (90-100):1; And / or, along the direction of rotation of the cathode part (2), the length from the first anode plate (41) to the last anode plate (4) is the length of the anode part (3), and the second anode plate (42) is arranged in an area of ​​5% to 10% of the length of the anode part (3).

7. The method for preparing electrolytic copper foil according to claim 3, wherein: The pulse current passed through the penultimate anode plate (43) is a second bidirectional pulse current, which includes a second positive current and a second negative current to form a cycle; wherein, The ratio of the time during which the second positive current is on to the time during which the second negative current is on is (10-20):1; And / or, the duty cycle of the second bidirectional pulse current is 98% to 100%; And / or, a ratio of a peak current of the second forward current to a peak current of the second negative current is (95-100):1; And / or, along the direction of rotation of the cathode portion (2), the length from the first anode plate (41) to the last anode plate (4) is the length of the anode portion (3), and the penultimate anode plate (43) is arranged in an area of ​​90% to 95% of the length of the anode portion (3).

8. An electrolytic copper foil device, characterized in that: include: The cathode portion (2) is connected to a DC power supply; an anode portion (3), connected to a DC power supply and a pulse power supply; An electrolytic cell (1), wherein the cathode portion (2) and the anode portion (3) are arranged in the electrolytic cell (1); an electrolyte container (5), connected to the electrolytic cell (1); A detection device (6) for detecting the copper ion concentration in the electrolyte in the cavity of the electrolyte container (5); The ultrasonic device (7) is used to apply ultrasonic waves to the electrolyte.

9. The electrolytic copper foil equipment according to claim 8, characterized in that: The cathode part (2) is a roller structure, the anode part (3) surrounds the working surface of the cathode part (2), and the anode part (3) includes a plurality of anode plates (4), and the anode plates (4) are arranged in sequence and connected in parallel with each other; The cathode portion (2) rotates relative to the anode portion (3), and along the direction of rotation of the cathode portion (2), the cathode portion (2) passes through each of the anode plates (4) in sequence, wherein the first anode plate (41), the second anode plate (42) and the penultimate anode plate (43) are connected to a pulse current power supply, and the remaining anode plates (4) are connected to a DC power supply.

10. A copper foil, characterized in that: The copper foil is produced by the method for producing the electrolytic copper foil according to any one of claims 1 to 7, or by the apparatus for producing the electrolytic copper foil according to claim 8 or 9; the copper foil has an Ra value of ≤1.4 μm; And / or, the tensile strength of the copper foil is ≥20 MPa; And / or, the difference between the transverse elongation and the longitudinal elongation of the copper foil is ≤1%.

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