A method for preparing zero-stress electrolytic metal foil and applications of the system and method used therefor

Abstract

The present invention belongs to the field of electrochemistry, and particularly relates to a method for preparing zero-stress electrolytic metal foil, and the application of the system and method used therefor. The method includes: 1) setting a movable conductive medium, the conductive medium can dynamically pass through the electrolyte, and when in the electrolyte, the conductive medium is electrically connected to the anode disposed in the electrolyte, and the conductive medium is used as the cathode to perform the electro-deposition preparation of the metal foil on the conductive medium to obtain a conductive medium-metal foil; 2) separating and removing the conductive medium component in the conductive medium-metal foil by means of phase change and / or chemical method and / or dissolution and / or expansion and contraction method, that is, completing the zero-stress preparation of the electrolytic metal foil. Through the improvement of the process, the present invention can effectively control the preparation thickness, size specifications, etc. of the electrolytic metal foil and carry out continuous production, with extremely strong applicability, high product yield, and high economic benefits.

Description

Technical Field

[0001] The present invention belongs to the field of electrochemistry, and particularly relates to a method for preparing electrolytic metal foil with zero stress, and the application of the system and method used therefor. Background Art

[0002] A metal foil is a thin sheet-like metal product. For example, a copper foil is usually made of copper with a certain proportion of other metals. Generally, the copper content of commercially available copper foils is 80wt% or 90wt% respectively, corresponding to 80 foil and 90 foil. In the past market environment, its most extensive use was as a decorative material because it has the characteristic of low surface oxygen and can adhere to various different substrates, such as metals, insulating materials, etc., and has a wide temperature range of use.

[0003] However, with the development of metal foils, various demands have emerged in the market. For example, in the field of copper foils, the developed high-purity electronic-grade copper foils with a copper content ≥ 99.7wt% are also commonly used in electronic devices due to their excellent electrical conductivity and the effect of providing electromagnetic shielding. Electronic-grade copper foil is one of the basic materials of the electronics industry. With the rapid development of the electronic information industry, the usage of electronic-grade copper foil is increasing, and the products are widely used in industrial calculators, communication equipment, QA equipment, lithium-ion copper foils, copper foil batteries, civilian televisions, video recorders, CD players, copiers, telephones, air conditioners, automotive electronic components, game consoles, etc. The demand for electronic-grade copper foils, especially high-performance electronic-grade copper foils, is increasing both at home and abroad.

[0004] Previously, the inventor of the present invention has conducted corresponding research and development on the metal foil preparation process, and has jointly applied for three invention patent applications, namely CN202111335008.X, CN202111335007.5, and CN202111335012.6, with corresponding cooperation units. In the above three patent applications, the effective and non-destructive preparation of ultra-thin and ultra-high-purity metal foils has been achieved, which can be very useful for the preparation of high-standard ultra-thin special metal foils. However, it has also been found in the actual industrialization process that when producing and preparing large-thickness and large-size metal foils through the above three invention patent technologies, problems such as wrinkles and fractures are very likely to occur. It has good production adaptability for small-size ultra-thin special copper foils and other metal foils with a thickness of 1 - 3μm or even below 1μm, and can achieve good quantitative production and generate huge economic benefits. However, for the continuous production of metal foils with a conventional thickness of 3 - 8μm, especially the production of large-size metal foil rolls, the production adaptability is poor, it cannot be effectively achieved, and the cost is relatively high.

[0005] In the existing technology, there are also obvious defects in the production of electrolytic metal foils with a thickness of 4-6 μm. That is, in the existing electrolysis method, the metal foil is directly deposited on the cathode roller or the intermediate material on the surface of the cathode roller. However, when peeling, only the metal foil is peeled off, resulting in the metal foil being very prone to tearing, leading to poor quantitative production effects. Currently, even the existing electrolysis process with high-standard and refined production can only basically apply and adapt to the continuous production of metal foil rolls with a thickness of more than 6 μm. Even more, most of the equipment that cannot achieve high-precision and refined preparation can only prepare thick copper foils with a thickness of more than 18 μm. Summary of the Invention

[0006] To solve the problems that in the existing electrolytic metal foil preparation process, the metal foil bears great stress during peeling, resulting in easy fracture and damage, and the existing other processes cannot effectively adapt to the efficient and lossless continuous production of 3-6 μm metal foils, etc., the present invention provides a zero-stress electrolytic metal foil preparation method, as well as its application and the obtained metal foil.

[0007] The primary object of the present invention is as follows:

[0008] 1. It can effectively adapt to the electrolytic preparation of any kind of existing metal foil;

[0009] 2. It can achieve zero-stress peeling of the metal foil, improving the yield rate of the metal foil;

[0010] 3. It can achieve the continuous production of 2-8 μm metal foils;

[0011] 4. It can reduce the production cost of high-quality metal foils;

[0012] 5. It can independently achieve the control and adjustment of the microscopic morphology and texture coefficient of the metal foil surface.

[0013] To achieve the above object, the present invention adopts the following technical solutions.

[0014] A zero-stress electrolytic metal foil preparation method,

[0015] The method includes:

[0016] 1) Set a movable conductive medium. The conductive medium can dynamically pass through the electrolyte, and when in the electrolyte, the conductive medium is electrically connected to the anode provided in the electrolyte. Using the conductive medium as the cathode, electro-deposition preparation of the metal foil is carried out on the conductive medium to obtain a conductive medium-metal foil;

[0017] 2) Separate and remove the conductive medium component in the conductive medium-metal foil by means of phase change and / or chemical method and / or dissolution and / or expansion and contraction method, that is, complete the zero-stress preparation of the electrolytic metal foil.

[0018] Preferably, the movable conductive medium described in step 1) enters the electrolyte in the form of a strip and / or a sheet of the target shape and / or a shaped and cured slurry.

[0019] Preferably, the shaped and cured slurry is filled into a specific carrier for gravity leveling and / or topography pressing, and after curing, it serves as the conductive medium.

[0020] Preferably,

[0021] The electrolyte described in step 1) contains a soluble metal salt of the target metal foil component;

[0022] The anode in step 1) is an insoluble anode.

[0023] For the method of the present invention, its core lies in completely avoiding the peeling process in the traditional preparation method and ensuring a high degree of flexibility in the implementation and use of the solution. And the core of the technical concept of the present invention is also significantly different from the prior basic solution. In the three atomic method (or gas phase method) solutions of CN202111335008.X, CN202111335007.5, and CN202111335012.6 developed by the inventors of the present application, the core lies in gravity peeling, and the metal foil is detached and obtained through the action of gravity. Therefore, it is actually more suitable for the preparation of sheets within a certain specification. And because it uses evaporation plating, an atomic deposition method, to achieve ultra-high-precision preparation, it also limits the production specification size and thickness, and increases the process difficulty and cost. Its core lies in the preparation, elimination, and gravity peeling of the intermediate layer to achieve the spontaneous shedding of the metal foil. While the core of the present application lies in selecting an appropriate conductive medium, using the conductive medium as a template to first perform electrolysis, and then using the lost foam method core to remove the conductive medium, completely avoiding the "peeling" process. The atomic method still has not escaped the "peeling" process. It provides a novel peeling form and combines the gas phase deposition method to achieve the effective and non-destructive preparation of ultra-thin metal foils, but the metal foil is still subjected to a large peeling stress. The present invention can completely avoid the peeling stress and achieve a completely non-destructive separation of the medium and the metal foil.

[0024] The influence of stress is very significant whether it is for the preparation of ultra-thin metal foils or large-scale metal foils. The original gas phase method solution reduces the stress on the metal foil and combines a specific deposition form to achieve the preparation of ultra-thin special metal foils, but it cannot overcome the influence of gravity stress on large-scale metal foils and cannot overcome the limitation of the deposition method used on the thickness. The present invention realizes continuous production with completely zero stress and combines a mature electrolysis process to achieve continuous and thickness-controlled production.

[0025] In addition, the method of the present invention also combines the advantages of various technologies. For example, it combines the advantages of low cost, high efficiency, and simplicity of the electrolysis method, and also the advantage of controllable microtopography brought by the conductive medium. By using galvanized aluminum foil with a nanobowl structure on the surface as the conductive intermediate layer, a metal foil with a thickness of 2 - 6 μm and superhydrophobic properties can be achieved.

[0026] In addition, when various technologies are effectively combined, the selection range of the conductive medium is greatly broadened. Since the thickness of the conductive medium is selected to be relatively thin, even some organic film materials can be selected as the conductive medium, making low conductivity no longer a technical obstacle for electrolytic deposition of metal foil. Moreover, through controlling the travel, travel rate, and current density of the conductive medium in the electrolyte, the present invention can control the thickness of the electrolytic metal foil, and even can achieve the preparation of multiple foils in a single pass, greatly improving the preparation efficiency and effect.

[0027] A zero - stress electrolytic metal foil system

[0028] The system is used for electro - depositing a conductive medium, and it includes a deposition device and a post - treatment device;

[0029] The deposition device includes an electrolytic cell, a cathode, an anode, and a power supply;

[0030] The cathode, anode, and power supply are electrically connected;

[0031] The electrolytic cell is used to hold the electrolyte. The anode is arranged in the electrolytic cell, and the cathode is electrically connected to the conductive medium, taking the conductive medium as an extension of the cathode, so that the conductive medium exists as a cathode in the electrolytic cell for electro - deposition;

[0032] The post - treatment device is used to remove the conductive medium, and it includes a solvent pool and / or a heating device and / or a refrigeration device and / or a combustion device and / or an atmosphere treatment device.

[0033] Preferably,

[0034] The system further includes a conveying device for transporting the conductive medium.

[0035] Preferably,

[0036] The system further includes a pre - treatment device;

[0037] The pre - treatment device loads the conductive medium onto a carrier and / or performs surface treatment on the conductive medium;

[0038] The carrier moves driven by the conveying device, carrying the conductive medium through the deposition device and the post - treatment device in sequence.

[0039] Preferably, the pretreatment device includes a spraying device and / or a brushing device and / or a solvent bath and / or a heating device and / or a refrigerating device and / or a UV curing device and / or a spraying device.

[0040] For the system used in the present invention, the most core parts are the deposition device and the post-treatment device. Due to the high flexibility of the method scheme of the present invention, it can be freely adjusted and selected according to needs during actual use. Therefore, the present invention only describes and explains the core and irreplaceable parts in detail.

[0041] For example, for the deposition device, it is actually quite similar to a conventional electro-deposition device. However, the most significant difference is that a conventional electro-deposition device needs to ensure that at least half of the cathode is immersed in the electrolyte, and the formed electrolytic metal foil is directly peeled off on the cathode. In the present invention, the conductive medium is used as an extension of the cathode, actually serving as a "second cathode" that "moves continuously and can be consumed". Therefore, the cathode can be completely removed from the electrolyte and is preferably also completely removed from the electrolyte. Even the cathode can be essentially regarded as a conductive joint, and its function is only to conduct electricity and distinguish the anode. This also avoids the deposition and consumption of metal ions on the cathode surface when the cathode is placed in the electrolyte, and the continuous accumulation of deposits on the cathode surface changes the progress of the conductive medium.

[0042] In addition, the post-treatment device is more flexibly selected according to the material of the conductive medium. For example, in the case of conductive carbon cloth as the conductive medium, the low oxygen partial pressure can be controlled by an atmosphere treatment device, and incomplete combustion can be carried out in cooperation with a combustion device, which not only ensures the complete removal of the carbon cloth component, but also the CO gas formed by incomplete combustion can avoid the oxidation of the metal foil, and at the same time can also eliminate the internal stress of the metal foil to a certain extent. Another example is that the PAN / PMMA conductive film can be quickly dissolved and removed by a solvent, which can effectively protect and clean the metal foil. Also, when preparing a metal foil with an alloy strip such as a copper alloy as the conductive medium, reasonable settings can make the linear thermal expansion coefficients of the alloy strip and the metal foil vary greatly, and even separation can be achieved through appropriate heat and cold alternating treatments, and at the same time, the internal stress of the metal foil can be effectively improved. It can be seen that for the technical solution of the present invention, through the reasonable application of known material properties, based on the core of the technical concept of the present invention, it is possible to achieve the non-destructive separation of the metal foil by combining any number of methods.

[0043] For the conveying device, it can also be freely selected according to the conductive medium and the carrier. For example, a belt-shaped conductive medium can be simply driven by a roller for conveying.

[0044] The pretreatment device is another feature of the system of the present invention. Since some conductive media are difficult to prepare, use, or have insufficient strength on a large area, or have special requirements for the shape of metal foils, etc., they need to be used in combination with a carrier. Therefore, the conductive medium is first prepared on the carrier through the pretreatment device, and then the conductive medium on the carrier is removed through the post-treatment device to separate the metal foil. The process of preparing in combination with the carrier is superficially closest to the previously developed solution. However, it should be noted that this solution of the present invention is only applicable to the preparation of metal foils that need to achieve a specific shape or specific morphology, that is, the microscopic morphology on the surface of the conductive medium with insufficient strength is "symmetrically imprinted" on the surface of the metal foil through the replication method to achieve the regulation of the microscopic morphology of the metal foil, or to specifically achieve the preparation of, for example, hexagonal metal foils. It is still an improved solution that is optimized in many aspects in combination with the overall technical solution of the present invention. The above effects cannot be achieved by the atomic deposition method.

[0045] Another use of the pretreatment device is to treat the surface of the conductive medium. For example, the texture of the metal foil can be controlled by additive treatment, etc., and the preparation effect of the metal foil of the present invention is further enhanced by the additive.

[0046] Application of a zero-stress electrolytic metal foil preparation method

[0047] The method is used to produce metal foils with a thickness dimension ≥ 2 μm, and / or to produce large-size metal foils with a length dimension specification ≥ 3 m and a width dimension specification ≥ 1.2 m, and / or to continuously produce metal foil rolls.

[0048] In the specific production test of the technical solution of the present invention, the continuous production and preparation of ultra-long and extra-large specification metal foil rolls can be achieved. The thickness of the metal foil contained in the metal foil roll is 4.2 μm, the width reaches 1.35 m, and the total length reaches 220 m. It can be seen that it can actually be used for the quantitative production of extra-large specification metal foils and meets the standards of industrial maturity.

[0049] The beneficial effects of the present invention are:

[0050] Through the improvement of the process, the present invention can effectively control the preparation thickness, size specification, etc. of the electrolytic metal foil and carry out continuous production, with extremely strong applicability, high product yield, and high economic benefits. At the same time, the technical solution of the present invention can also effectively control the surface morphology of the metal foil, and has the advantages of a wide range of applications, strong process flexibility, and high industrial maturity. Description of the Drawings

[0051] Figure 1 It is a schematic diagram of the system of Embodiment 1 of the present invention;

[0052] Figure 2 It is one of the partial structural schematic diagrams of the deposition device of Embodiment 1 of the present invention;

[0053] Figure 3 One of the partial structural schematic diagrams of the deposition device according to Embodiment 1 of the present invention;

[0054] Figure 4 One of the partial structural schematic diagrams of the deposition device according to Embodiment 1 of the present invention;

[0055] Figure 5 Schematic diagram of the conductive carrier according to Embodiment 3 of the present invention;

[0056] Figure 6 Schematic diagram of the system according to Embodiment 3 of the present invention;

[0057] Figure 7 Schematic diagram of the system according to Embodiment 4 of the present invention;

[0058] Figure 8 Partial structural schematic diagram of the deposition device according to Embodiment 4 of the present invention;

[0059] Figure 9 Schematic diagram of the system according to Embodiment 5 of the present invention;

[0060] Figure 10 Partial structural schematic diagram of the deposition device according to Embodiment 5 of the present invention.

[0061] In the figure: 100 conveyor device, 200 pre-treatment device, 201 treatment liquid spray head, 202 ink droplet head, 203 UV lamp, 204 medium material spray head, 205 cold air cylinder, 300 deposition device, 301 cathode, 302 anode, first anode 302a, second anode 302b, 303 power supply, 304 electrolytic cell, 3041 main tank, 3042 auxiliary tank, 3043 through tank, 305 deposition roller, 306 scraper, 400 post-treatment device, 401 flame spray head, 402 box-type atmosphere furnace, 4021 intake pipe, 4022 exhaust pipe, 403 spraying device, 500 reel, A conductive medium, A01 conductive copper alloy strip, A011 die groove, A012 insulating layer, B medium-foil, B01 conductive medium layer, B02 foil layer, C product foil, C01 first electrolytic copper foil, C02 second electrolytic copper foil. Detailed implementation manners

[0062] The following further clearly and detailedly describes the present invention in combination with specific embodiments and the accompanying drawings of the specification. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following descriptions are usually only some of the embodiments of the present invention, rather than all of the embodiments. Therefore, all other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention shall fall within the scope of protection of the present invention.

[0063] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "thickness", "upper", "lower", "horizontal", "top", "bottom", "inner", "outer", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined. The meaning of "several" means one or more.

[0064] In the present invention, unless otherwise clearly specified and limited, terms such as "install", "connect", "couple", "fix", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or communicable with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0065] Unless otherwise specified, the raw materials used in the embodiments of the present invention are all commercially available or raw materials that can be obtained by those skilled in the art; unless otherwise specified, the methods used in the embodiments of the present invention are all methods mastered by those skilled in the art.

[0066] Example 1

[0067] The technical solution of the present invention is illustrated by taking a system with strong universality and high industrial maturity as an example. As Figure 1 shown in the schematic diagram, the system of the present invention includes a conveying device 100, a pre-treatment device 200, a deposition device 300, and a post-treatment device 400;

[0068] This set of system operated well from January 2022 to May 2022 and was specifically used for the preparation of oxygen-free electrolytic copper foil. In this system, the conveying device 100 uses a commercially available roller conveying device 100, and electric rollers are used as the conveying device 100 for conveying. The conductive medium A used in the present invention is a commercially available roll of PU conductive film, with a size specification of 1.2 m × 60 m. Under the action of the conveying device 100, the conductive medium A (PU conductive film) of this embodiment is first sent to the pretreatment device 200. In the pretreatment device 200, an atomizing nozzle is provided as the treatment liquid nozzle 201 in this embodiment. The treatment liquid nozzle 201 evenly sprays a 50 wt% aqueous solution of polyethyleneimine on the deposition surface of the conductive medium A film. Through the control of the feeding rate of the conveying device 100 and the flow rate of the treatment liquid nozzle 201, the spraying amount on the surface of the deposition surface of the conductive medium A film is about 12 - 15 g / m 2 , and then, driven by the conveying device 100, the conductive medium A film enters the deposition device 300. As can be seen from Figure 1 , in the deposition device 300 of the system of this embodiment, the cathode 301 is arranged outside the electrolytic cell 304. The conductive medium A film first passes through the cathode 301 and adheres to the cathode 301. When the conductive medium A film enters the electrolyte in the electrolytic cell 304, it can form an electro-deposition as an extension of the cathode 301;

[0069] The anode 302 is a commercially available graphite anode 302 and is arranged at the bottom of the electrolytic cell 304. The power supply 303 is a thyristor power supply 303 purchased from SanRex. The electrolytic cell 304 is filled with electrolyte. The electrolyte in the electrolyte is a 280 - 320 g / L copper sulfate pentahydrate solution, which also contains 120 g / L sulfuric acid and 10 mg / L gelatin. The copper ion concentration in the electrolyte is dynamically controlled by adding copper sulfate pentahydrate through feeding;

[0070] When the conductive medium A film enters the electrolytic cell 304, the deposition surface faces downward and faces the anode 302. After the power supply 303 is turned on, the electrolytic cell 304 operates to achieve electro-deposition on the deposition surface of the conductive medium A film, and the preparation of electrolytic copper foil is carried out. Subsequently, after the preparation of the electrolytic copper foil is completed on the deposition surface of the conductive medium A film, the medium-foil B (i.e., the PU conductive film medium-electrolytic copper foil composite) is sent out of the deposition device 300 through the conveying device 100 and sent into the post-treatment device 400;

[0071] Specifically, the partial structural schematic diagram of the constructed deposition device 300 except for the power supply 303 part is as shown in Figure 2 , Figure 3 and Figure 4As shown, it can be clearly seen that through the deposition device 300 and the specifically arranged anode 302, effective deposition can be achieved on the deposition surface of the conductive medium A thin film, and after deposition, the medium-foil B composed of the conductive medium A and the product foil C (copper foil) is formed; in this embodiment, the post-treatment device 400 is composed of an atmosphere treatment device and a combustion device. The atmosphere treatment device is a box-type atmosphere furnace 402, and the combustion device is a flame nozzle 401, and the flame nozzle 401 extends into the box-type atmosphere furnace 402. The box-type atmosphere furnace 402 is provided with an intake pipe 4021 and an exhaust pipe 4022. The intake pipe 4021 feeds a low oxygen partial pressure gas, and the oxygen concentration in the gas is ≤ 14% VOL. In this embodiment, the oxygen concentration in the passed gas is controlled to be 12 - 14% VOL. The exhaust pipe 4022 is used to exhaust the combustion gas. The intake pipe 4021 is arranged at the top of the box-type atmosphere furnace 402, and the exhaust pipe 4022 is arranged at the bottom of the box-type atmosphere furnace 402, forming an environment that is more conducive to deoxidizing the electrolytic copper foil and avoiding oxidation. The flame nozzle 401 is aligned with the conductive medium A thin film layer of the medium-foil B, and continuous flame spraying is carried out to burn and remove the PU film. The gas flow rate of the intake pipe 4021 and the gas flow rate of the exhaust pipe 4022 are controlled, and the gas discharged from the exhaust pipe 4022 is detected to ensure that the discharged gas contains at least 2% VOL of CO to ensure incomplete combustion in the box-type atmosphere furnace 402, but it is necessary to ensure the complete combustion and removal of the PU film. After this process, the product foil C (i.e., the metal foil, oxygen-free copper foil) is obtained. The obtained product foil C is then driven and towed out of the post-treatment device 400 by the conveying device 100 and wound and stored with the help of the reel 500, and the oxygen-free copper foil product is obtained.

[0072] The oxygen content of the oxygen-free copper foil product is characterized, and the characterization result shows that the oxygen content in the obtained product foil C is 3.1 - 3.5 ppm, meeting the oxygen-free copper foil standard, and the oxygen content is extremely low.

[0073] In addition, samples are taken from the intermediate product of the medium-foil B, and the copper foil is peeled and separated to characterize its oxygen content. The characterization result shows that its oxygen content is 2.8 - 3.2. It can be seen that in the subsequent post-treatment process, the oxygen content is not significantly increased.

[0074] In addition, in this embodiment, the current density is controlled to be 3 A / dm 2 , the electrolyte temperature is 50 °C. The conveying device 100 is used to control the load time of the conductive medium A from entering the electrolyte to exiting the electrolyte. In this embodiment, the load time is 4 min. The thickness of the obtained product foil C is 3.3 μm, and its tensile strength is characterized. The characterization result shows that its tensile strength can reach 462 MPa, having very excellent tensile properties.

[0075] Example 2

[0076] On the basis of Example 1, adjustment tests were carried out on the electrodeposition parameters and some variable parameters of the product, and the product foil C was characterized, and the results shown in the following table were obtained. Among them, when characterizing the product thickness, when the maximum thickness (δ max ) and the minimum thickness (δ min ) satisfy δ max -δ min ≤0.03 μm, the average thickness of ten measurements is recorded. If not satisfied, the maximum and minimum value intervals are recorded. The product characterization accuracy is 0.05 μm.

[0077] Current density Load time Other variables Product thickness Tensile strength <![CDATA[2A / dm 2 > 3 min None 1.55 μm 371 MPa <![CDATA[2A / dm 2 > 4 min None 2.1 μm 400 MPa <![CDATA[2A / dm 2 > 5 min None 2.65 μm 429 MPa <![CDATA[2A / dm 2 > 6 min None 3.2 μm 460 MPa <![CDATA[3A / dm 2 > 3 min None 2.4 μm 413 MPa <![CDATA[3A / dm 2 > 4 min None 3.3 μm 462 MPa <![CDATA[3A / dm 2 > 5 min No pretreatment 4.0 μm 407 MPa <![CDATA[3A / dm 2 > 6 min None 4.8 μm 539 MPa <![CDATA[4A / dm 2 > 3 min None 3.2 μm 455 MPa <![CDATA[4A / dm 2 > 4 min None 4.3 μm 516 MPa <![CDATA[4A / dm 2 > 5 min None 5.35 μm 561 MPa <![CDATA[4A / dm 2 > 6 min None 6.4 μm 620 MPa <![CDATA[5A / dm 2 > 3 min None 4.0 μm 492 MPa <![CDATA[5A / dm 2 > 4 min None 5.3 μm 566 MPa <![CDATA[5A / dm 2 > 5 min None 6.8 μm 639 MPa <![CDATA[5A / dm 2 > 6 min None 7.9 μm 663 MPa <![CDATA[3A / dm 2 > 4 min No pretreatment 3.3 μm 372 MPa

[0078] Two rolls of copper foil were trial-produced for each of the above test groups. Their width specifications are 0.8 m and the lengths are all 62 m. Except for the copper foil obtained in the 2 A / dm 2 / 3 min test group having certain wrinkles, the copper foils produced by the remaining test groups are all without breakage and wrinkles.

[0079] As can be seen from the above table, for the technical solution of the present invention, the thickness of the product foil C can be controlled by adjusting the current density and the load time, and there is a certain coefficient correlation. Combining all previous tests, the thickness of the product foil C produced can be controlled by an empirical formula in actual production. The specific empirical formula is as follows:

[0080] d = A + B×J + C×T

[0081] In the formula: d is the thickness of the product foil C, in μm; A, B, and C are all empirical coefficients. A is affected by the composition of the metal foil, in μm; B and C are affected by factors such as the distance between the anode 302 and the deposition surface, the setting position of the anode 302, and the traveling route of the conductive medium A on the deposition surface. The unit of B is μm·dm 2 / A, the unit of C is μm / min, J is the current density, in A / dm 2 , and T is the load time, in min.

[0082] The above formula can calculate the empirical coefficients A, B, and C after three trial productions and perform a simple fitting to obtain a reference formula for actual production to guide actual production. The more times of trial production, the higher the accuracy of the obtained reference formula.

[0083] In addition, through tests with other variables, it can be seen that for the technical solution of the present invention, the pretreatment device 200 does not affect the thickness of the product foil C produced, that is, the treatment agent in this embodiment has no obvious effect on the thickness of the copper foil, but has a relatively significant effect on the mechanical properties of the copper foil. For example, in this embodiment, the tensile strength of the copper foil can be effectively improved by spraying and using polyethyleneimine. It can be seen that the pretreatment device 200 has a good performance in improving the properties of the copper foil. The pretreatment scheme in this embodiment is adjusted based on the technical achievements of the industry-university-research cooperation project, such as 202110636882.0, 202110638177.4, etc.

[0084] Comparative Example 1

[0085] Based on the technical solution of Example 1, the only difference is as follows:

[0086] Through the conveying device 100, the medium-foil B prepared by the deposition device 300 is sent to a full-automatic stripping machine (commercially available: Maida Pu full-automatic copper foil stripping machine) for the stripping and separation treatment of the conductive medium A and the product foil C (copper foil).

[0087] Comparing with the technical solution of Example 1, the time required for Example 1 to separate and prepare a 1.2m×60m copper foil through the post-treatment device 400 is 26 minutes, while the time required for Comparative Example 1 to use the full-automatic stripping machine for stripping and separation treatment is 2 hours and 11 minutes. It can be seen that there is a huge difference in efficiency. In addition, during the whole process of the post-treatment device 400 in Example 1, the copper foil has no breakage and no wrinkles, and the product yield rate reaches 100%. However, in Comparative Example 1, when using the full-automatic stripping machine, there are 6 slight breakages on the copper foil and several wrinkles. The tensile strengths of the copper foils prepared by the two are characterized. The characterization result of Example 1 is 462 MPa, while the characterization result of Comparative Example 1 is only about 417 MPa. It can be seen that the stripping treatment will have a certain adverse effect on the mechanical properties of the copper foil, and it is easy to cause breakage of the copper foil, and the treatment efficiency is low. It can be seen that the technical solution of the present invention has obvious superiority compared with the conventional electrolytic metal foil preparation scheme.

[0088] Comparative Example 2

[0089] Based on the previously developed atomic method scheme, a horizontal comparison preparation test is carried out with the technical solution of this application.

[0090] Based on the specific scheme of Example 3 in the technical solution of 202111335007.5, by adjusting the gas-phase deposition time to control the thickness of the atomic layer (copper foil), copper foil sheets with thicknesses of 1.2 μm, 3.2 μm, and 6.8 μm and size specifications of 0.8m×1.0m are respectively prepared, as well as a foil roll with a continuous production thickness of 3.2 μm and size specifications of 0.6m×22m.

[0091] Based on the technical solution of Embodiment 1, a foil roll with the same thickness of 3.2 μm and the size specification of 0.6 m × 22 m is produced without pre-treatment.

[0092] Embodiment 3

[0093] Build a production system for metal foil:

[0094] Use the conductive copper alloy strip A01 as the conductive carrier. The conductive copper alloy strip A01 has a thickness of 2.2 cm and has good flexibility and conductivity.

[0095] Specifically, as Figure 5 shown, on one side of the conductive copper alloy strip A01 (beryllium bronze alloy strip of C17000 grade), a die groove A011 with a specification of 0.8 m × 1.0 m is opened. The side of the conductive copper alloy strip A01 with the die groove A011 is subjected to insulation treatment to form an insulating layer A012, and the side wall surface of the die groove A011 is also subjected to insulation treatment to form an insulating layer A012.

[0096] The die groove A011 is filled with UV-curable conductive ink until it can level by gravity to cover the bottom of the die groove A011. The UV-curable conductive ink in this embodiment is commercially available and purchased from Yuxi New Materials.

[0097] The overall system is as Figure 6 shown, including the same electric roller as in Embodiment 1 as the conveying device 100, which is used to convey the conductive copper alloy strip A01 as the conductive carrier.

[0098] The conductive copper alloy strip A01 first enters the pre-treatment device 200. For this embodiment, the pre-treatment device 200 is provided with an ink dropper 202 and a UV lamp 203. The ink dropper 202 drops UV-curable conductive ink into the die groove A011 of the conductive copper alloy strip A01, and realizes gravity leveling before reaching the irradiation range of the UV lamp 203 during the conveying process of the conductive copper alloy strip A01, and then is cured by the UV lamp. As Figure 6 shown in the partial enlarged view in, a conductive medium A film (UV-curable conductive ink film) is formed in the die groove A011, and then it enters the deposition device 300 under the drive of the conveying device 100. The deposition device 300 in this embodiment is similar to that in Embodiment 1, including a cathode 301, an anode 302, an electrolytic cell 304 and a power supply 303.

[0099] The cathode 301 is arranged outside the electrolytic cell 304. The back surface of the conductive copper alloy strip A01 (the side with the die groove A011 is the front surface, and the opposite surface is the back surface) first passes through the cathode 301 and is attached to the cathode 301. After the conductive copper alloy strip A01 enters the electrolyte in the electrolytic cell 304, the conductive copper alloy strip A01 and the UV-curable conductive ink film (conductive medium A film) can form electroplating as an extended part of the cathode 301;

[0100] The anode 302 is a commercially available graphite anode 302, which is arranged at the bottom of the electrolytic cell 304. The power supply 303 is a thyristor power supply 303 purchased from SanRex. The electrolytic cell 304 is filled with electrolyte. The electrolyte in the electrolyte is a 280 - 320 g / L copper sulfate pentahydrate solution, which also contains 120 g / L sulfuric acid and 10 mg / L gelatin. The copper ion concentration in the electrolyte is dynamically controlled by adding copper sulfate pentahydrate through feeding;

[0101] When the conductive medium A film enters the electrolytic cell 304, the deposition surface faces downward and faces the anode 302. After the power supply 303 is turned on, the electrolytic cell 304 operates to perform electroplating on the deposition surface of the conductive medium A film to prepare electrolytic copper foil. Subsequently, after the electrolytic copper foil is prepared on the deposition surface of the conductive medium A film, the conductive copper alloy strip A01 carrying the medium-foil B (i.e., the UV-curable conductive ink film - electrolytic copper foil composite) is sent out of the deposition device 300 by the conveying device 100 and sent into the post-treatment device 400;

[0102] The post-treatment device 400 includes a solvent tank, and the solvent tank is cooperated with a heating device to heat the solvent in the solvent tank. The solvent tank is filled with an acetone - cyclohexanone solution, in which acetone and cyclohexanone are mixed in a volume ratio of 1:3. The heating device heats the acetone - cyclohexanone solution in the solvent tank to 85 °C, and the conductive copper alloy strip A01 carrying the medium-foil B is put into the solvent tank for hot dipping treatment. During this treatment process, the conductive medium A film is partially softened and dissolved, and the viscosity is significantly reduced, so that the product foil C on the surface of the conductive medium A film falls off into the solvent tank;

[0103] The bottom of the solvent pool is sloped, and a diversion opening is provided at the low slope end. The acetone-cyclohexanone solution flows out from this diversion opening and drives the detached electrolytic copper foil away from the solvent pool to recover the product foil C. For the recovery, the solvent and the electrolytic copper foil can be pre-stored in a recovery barrel and cooled to room temperature before fishing out the electrolytic copper foil. Or, as in this embodiment, a more optimal solution can be adopted. In this embodiment, an inclined plate separator is used, so that the electrolytic copper foil can be intercepted on the slope plate of the inclined plate separator by surface tension and friction, while the solvent part flows to the bottom of the slope for separation. Using an inclined plate separator is less likely to damage the electrolytic copper foil compared to the method of fishing and recovering with a recovery barrel. Especially for ultra-thin copper foils, the fishing process is likely to cause a certain degree of bending or wrinkling of the electrolytic copper foil. In addition, a liquid pump is provided in this embodiment in cooperation with the inclined plate separator, and the liquid pump pumps the separated solvent back into the solvent pool for use; and from Figure 6 it can be seen that a large amount of the conductive medium A is also removed in the solvent pool, and the conductive copper alloy strip A01 can enter the pretreatment device 200 again under the drive of the conveyor device 100, realizing the single-strip recycling of the conductive copper alloy strip A01. Although the post-treatment device 400 cannot completely and effectively remove and clean the thin film component (UV-cured conductive ink thin film) of the conductive medium A, due to the characteristics of the supporting pretreatment device 200, the UV-cured conductive ink will undergo a gravity leveling process after dropping into the mold groove A011, and can ensure the flatness of the formed conductive medium A thin film within a certain period. Only the mold groove A011 needs to be cleaned regularly, with low process costs and the ability to quickly build a system to realize the production and preparation of medium and small batches of electrolytic metal foils.

[0104] In addition, the pretreatment device 200 can also load the conductive medium A on the conductive copper alloy strip A01 in the form of film sticking, such as sticking the PU conductive film recorded in Attachment Example 1. At this time, the front surface of the conductive copper alloy strip A01 is all subjected to oxidation insulation treatment. And in combination with the thermal expansion characteristics of the conductive copper alloy strip A01, the post-treatment device 400 is first correspondingly provided with a heating device, a refrigeration device, an atmosphere treatment device and a combustion device. First, the heating device and the refrigeration device are used to separate the conductive medium A thin film from the conductive carrier by the expansion and contraction method, and then the medium-foil B is recovered and treated with the atmosphere treatment device and the combustion device to remove the conductive medium A, realizing the effective preparation of the metal foil. This method is applicable to the preparation of smaller-sized, more delicate and more numerous small single-piece metal foils.

[0105] The metal foils (copper foils) prepared in Example 3 and Comparative Example 2 were characterized and analyzed as shown in the following table.

[0106] In addition, ten single foils (0.8 m × 1.0 m single foils) are taken respectively, and a judgment area of 5 × 5 cm is divided. If there are bad points in the judgment area (including deformation, obvious folds, scratches, holes, obvious corrosion marks, or obvious dirt that is difficult to remove, etc.), then this area is judged to be damaged. If it is at the boundary of several judgment areas, only one damaged judgment area is counted.

[0107] Calculate the bad point rate based on this. The results are shown in the following table.

[0108]

[0109] In the table: The gas-phase method is the method (iodine intermediate layer) described in Example 3 of the technical solution of 202111335007.5, and the zero-stress method is the method of the present invention.

[0110] It can be seen from the above table that compared with the gas-phase method, the zero-stress method itself has the advantage of electrolytically preparing copper foil. The texture characteristics of the electrolytic copper foil are more excellent than those of the vapor-deposited copper foil, and it has a larger texture coefficient of the (220) crystal plane. Therefore, its tensile strength is higher than that of the gas-phase method, that is, its mechanical properties are more excellent. However, when actually characterizing the oxygen content, due to its stricter control of the atmosphere, the oxygen content of the gas-phase method is lower. And from the bad point rate data, it can be seen that for preparing single metal foils within a certain specification, the bad point rate of the gas-phase method is lower. But once preparing long foil rolls, its bad point rate increases sharply, indicating that it is not suitable for preparing long foil rolls. When the present invention prepares special ultra-thin (1.2 μm thickness) metal foils, the bad point rate increases to a certain extent. However, it can be seen from the comparative experiment in Example 2 that the technical solution of the present invention basically has a good preparation effect on electrolytic metal foils above 2 μm.

[0111] Example 4

[0112] The method and system according to the technical solution of the present invention can also realize the synchronous preparation of two foil materials by a single system, and construct a double-foil system as shown in Figure 7 shown;

[0113] The double-foil system includes a conveying device 100, a deposition device 300, and a post-treatment device 400;

[0114] As shown in Figure 7 shown, under the action of the conveying device 100, the conductive medium A in this embodiment selects a low-melting-point PU conductive film with a melting point ≤ 136 °C. The conductive medium A enters the deposition device 300, from Figure 7 and Figure 8As can be seen, the cathode 301 of the deposition device 300 of the system in this embodiment is arranged outside the electrolytic cell 304. The conductive medium A thin film first passes through the cathode 301 and adheres to the cathode 301. After the conductive medium A thin film enters the electrolyte in the electrolytic cell 304, it can form electroplating as an extension part of the cathode 301;

[0115] The anode 302 is a commercially available graphite anode 302. This system is a dual-anode 302 system. The first anode 302a is arranged at the bottom of the electrolytic cell 304, and the second anode 302b is arranged at the top of the electrolytic cell 304. The first anode 302a and the second anode 302b face opposite sides of the conductive medium A respectively. The power supply 303 is a thyristor power supply 303 purchased from SanRex. The electrolytic cell 304 is filled with electrolyte. The electrolyte in the electrolyte is a 280-320 g / L copper sulfate pentahydrate solution, which also contains 120 g / L sulfuric acid and 10 mg / L gelatin. The copper ion concentration in the electrolyte is dynamically controlled by adding copper sulfate pentahydrate through feeding;

[0116] When the conductive medium A thin film enters the electrolytic cell 304, the first deposition surface faces downwards and towards the first anode 302a, and the second deposition surface faces obliquely upwards towards the second anode 302b. After the power supply 303 is turned on, the electrolytic cell 304 works to perform electroplating on the two deposition surfaces of the conductive medium A thin film to prepare electrolytic copper foil. Subsequently, after the electrolytic copper foil is prepared on the deposition surface of the conductive medium A thin film, the medium-foil B (i.e., the first electrolytic copper foil C01-PU conductive film medium-second electrolytic copper foil C02 composite body) is sent out of the deposition device 300 by the conveying device 100 and sent into the post-treatment device 400;

[0117] The post-treatment device 400 in this embodiment is composed of an atmosphere treatment device and a spraying device 403. The atmosphere treatment device is a box-type atmosphere furnace 402. The spraying device 403 is arranged in the box-type atmosphere furnace 402 and on the outlet side of the strip in the box-type atmosphere furnace 402, ensuring that the medium-foil B enters the box-type atmosphere furnace 402 and first undergoes atmosphere treatment and then passes through the spraying device 403. The box-type atmosphere furnace 402 is provided with an inlet pipe 4021 and an outlet pipe 4022. The inlet pipe 4021 feeds in a heat protection gas. In this embodiment, the heat protection gas controlled to be introduced is nitrogen at 150 °C. The outlet pipe 4022 is used to discharge gases and melted PU or PU particles. The inlet pipe 4021 is arranged at the top of the box-type atmosphere furnace 402, and the outlet pipe 4022 is arranged at the bottom of the box-type atmosphere furnace 402, which is more conducive to the electrolytic copper foil to discharge the melted PU or PU particles. After hot purging the molten PU conductive film conductive medium A, zero-stress separation of the first electrolytic copper foil C01 and the second electrolytic copper foil C02 is achieved. Moreover, the spraying device 403 is beneficial for more thoroughly removing the residual molten polyurethane. The liquid sprayed by the spraying device 403 is cyclohexanol heated to 135 °C. Cyclohexanol has the characteristics of being difficult to volatilize and having a high boiling point, and has good adaptability to the technical solution of the present invention. However, due to its slight toxicity and slight irritation, attention needs to be paid to recovery and protection of the staff during use;

[0118] The obtained product foils C (the first electrolytic copper foil C01 and the second electrolytic copper foil C02) are then jointly driven and pulled out of the post-treatment device 400 by the conveying device 100 and are respectively received by two drums 500.

[0119] In addition, in this embodiment, the current density is controlled to be 2.5 A / dm 2 , the electrolyte temperature is 50 °C. The conveying device 100 is used to control the load time of the conductive medium A from entering the electrolyte to exiting the electrolyte. In this embodiment, the load time is 5 min. The thickness of the obtained first electrolytic copper foil C01 is 3.8 μm, and its tensile strength is characterized. The characterization result shows that its tensile strength can reach 386 MPa. The thickness of the obtained second electrolytic copper foil C02 is 3.2 μm, and its tensile strength is characterized. The characterization result shows that its tensile strength reaches 369 MPa.

[0120] In addition, by controlling aspects such as the positions of the first anode 302a and the second anode 302b relative to the conductive medium A and the traveling distance of the conductive medium A in the electrolytic cell 304, simultaneous regulation of the thicknesses of the first electrolytic copper foil C01 and the second electrolytic copper foil C02 can be achieved, greatly improving the actual production and preparation efficiency, and enabling simple and efficient synchronous preparation of single-system double foil materials, which cannot be achieved by conventional electrolytic metal foil technology and gas-phase metal foil preparation technology.

[0121] Example 5

[0122] The method according to the technical solution of the present invention can also be combined with a conventional metal foil electrolysis system to form a continuous peeling type zero-stress electrolytic metal foil system as shown in Figure 9 and Figure 10 ;

[0123] The continuous peeling type zero-stress electrolytic metal foil system includes a conveying device 100, a deposition device 300 and a post-treatment device 400; as shown in Figure 9 , first, the deposition device 300 of the system in this embodiment includes an electrolytic cell 304, a cathode 301, an anode 302 and a power supply 303, as well as a specially arranged deposition roller 305 and a scraper 306;

[0124] Specifically, the deposition roller 305 is controlled to rotate by a motor brake, and it is preferably prepared from an insulating and scratch-resistant material. For example, in this embodiment, the deposition roller 305 is specifically prepared from wear-resistant corundum ceramics, which has extremely high surface flatness, and is high-strength, high-hardness, acid and alkali corrosion-resistant, and is not easy to deposit dirt on the surface. Therefore, it can be used as a good carrier for loading the conductive medium A;

[0125] The anode 302 is a commercially available graphite anode 302, which is arranged at the bottom of the electrolytic cell 304. The power supply 303 is a thyristor power supply 303 purchased from SanRex. The electrolytic cell 304 is filled with an electrolyte solution. The electrolyte solution is a 280-320 g / L copper sulfate pentahydrate solution, which also contains 120 g / L sulfuric acid and 10 mg / L gelatin. The copper ion concentration in the electrolyte solution is dynamically controlled by adding copper sulfate pentahydrate through feeding;

[0126] The electrolytic cell 304 in this embodiment is a double-tank electrolytic cell 304, which has a main tank 3041 and an auxiliary tank 3042 respectively. The main tank 3041 is used for electro-deposition, and the auxiliary tank 3042 is used for cooperating to control the liquid level of the electrolyte solution and the concentration of the electrolyte. A through-tank 3043 is provided between the main tank 3041 and the auxiliary tank 3042 for connection;

[0127] The cathode 301 used in this embodiment is a conductive cathode 301 roller, which can rotate freely and approach the deposition roller 305. The minimum distance between the conductive cathode 301 roller and the deposition roller 305 is the thickness of the conductive medium A. In the rotation direction of the deposition roller 305, a pre-treatment device 200 is provided at the front end of the cathode 301. The pre-treatment device 200 includes a medium material spray head 204 and a cold air cylinder 205. The medium material spray head 204 sprays the conductive medium A material (molten PU masterbatch) on the surface of the deposition roller 305. After being blown and cured by the cold air cylinder 205, it is pressed flat by the cathode 301 to form a conductive medium A film and enters the electrolyte solution in the electrolytic cell 304 under the drive of the deposition roller 305, and electro-deposition is carried out on the surface of the conductive medium A to form a medium-foil B;

[0128] The doctor blade 306 is arranged at the rear end in the rotation direction of the deposition roller 305, and the blade part abuts against the surface of the deposition roller 305. It can be symmetrically arranged with the cathode 301 and is arranged above the electrolyte, and is used for scraping and separating the medium-foil B and the deposition roller 305;

[0129] The separated medium-foil B is driven by the conveying device 100 to the post-treatment device 400;

[0130] In this embodiment, the post-treatment device 400 is composed of an atmosphere treatment device and a combustion device. The atmosphere treatment device is a box-type atmosphere furnace 402, and the combustion device is a flame nozzle 401 and the flame nozzle 401 extends into the box-type atmosphere furnace 402. The box-type atmosphere furnace 402 is provided with an inlet pipe 4021 and an outlet pipe 4022. The inlet pipe 4021 feeds a gas with a low oxygen partial pressure, and the oxygen concentration in the gas is ≤14% VOL. In this embodiment, the oxygen concentration in the passed gas is controlled to be 12-14% VOL. The outlet pipe 4022 is used to discharge the combustion gas. The inlet pipe 4021 is arranged at the top of the box-type atmosphere furnace 402, and the outlet pipe 4022 is arranged at the bottom of the box-type atmosphere furnace 402, forming an environment more conducive to deoxidation of the electrolytic copper foil and avoiding oxidation. The flame nozzle 401 is aligned with the conductive medium A thin film layer of the medium-foil B, and continuous flame spraying is carried out to burn and remove the PU film. The gas flow rate of the inlet pipe 4021 and the gas flow rate of the outlet pipe 4022 are controlled, and the gas discharged from the outlet pipe 4022 is detected to ensure that the discharged gas contains at least 2% VOL of CO to ensure incomplete combustion in the box-type atmosphere furnace 402, but it is necessary to ensure complete combustion and removal of the PU film. After this process, the product foil C (i.e., the metal foil, oxygen-free copper foil) is obtained. The obtained product foil C is then driven and towed by the conveying device 100 to the outside of the post-treatment device 400 and wound and stored by means of a reel 500, and the oxygen-free copper foil product is obtained.

[0131] The oxygen content of the oxygen-free copper foil product is characterized, and the characterization result shows that the oxygen content in the produced product foil C is 2.8-3.0 ppm, which meets the oxygen-free copper foil standard and the oxygen content is extremely low;

[0132] In addition, a sample is taken from the intermediate product medium-foil B, and the copper foil is peeled and separated to characterize its oxygen content. The characterization result shows that its oxygen content is 2.6-2.9. It can be seen that the oxygen content is not significantly increased during the subsequent post-treatment process.

[0133] In addition, in this embodiment, the current density is controlled to be 3 A / dm 2, the electrolyte temperature is 50°C. The loading time of the conductive medium A is calculated by the conveying device 100 from the time it enters the electrolyte to the time it exits the electrolyte. The loading time in this embodiment is 4 minutes. The thickness of the obtained product foil C is 3.0 μm, and its tensile strength is characterized. The characterization result shows that its tensile strength can reach 366 MPa, and it has very excellent tensile properties.

[0134] It can be seen that the technical solution of the present invention can be directly, simply and effectively applied to the existing electroplating system, and a certain degree of improvement can form the above-mentioned device cooperation and system.

Claims

1. A method for preparing zero-stress electrolytic metal foil, characterized in that, The method includes: 1) Setting a movable conductive medium, which can dynamically pass through the electrolyte, and when in the electrolyte, the conductive medium is electrically connected to the anode arranged in the electrolyte, and using the conductive medium as the cathode to perform the electro-deposition preparation of metal foil on the conductive medium to obtain a conductive medium-metal foil; 2) Separating and removing the conductive medium component in the conductive medium-metal foil in a way of phase change and / or chemical method and / or dissolution and / or expansion and contraction method that does not involve chemical reaction, that is, completing the zero-stress preparation of electrolytic metal foil.

2. The method for preparing zero-stress electrolytic metal foil according to claim 1, characterized in that, The conductive medium in step 1) is strip-shaped and / or sheet-shaped with a target shape and / or shaped and solidified slurry.

3. The method for preparing zero-stress electrolytic metal foil according to claim 2, characterized in that, The shaped and solidified slurry is filled into a carrier for gravity leveling and / or topography pressing, and after curing, it is used as the conductive medium.

4. The method for preparing zero-stress electrolytic metal foil according to claim 1, characterized in that, The electrolyte in step 1) contains soluble metal salts of the target metal foil component; The anode in step 1) is an insoluble anode.

5. A zero-stress electrolytic metal foil system, characterized in that, The system is used for electro-depositing a conductive medium, and it includes a deposition device and a post-treatment device; The deposition device includes an electrolytic cell, a cathode, an anode and a power supply; The cathode, the anode and the power supply are electrically connected; The electrolytic cell is used to accommodate the electrolyte, the anode is arranged in the electrolytic cell, the cathode is electrically connected to the conductive medium, and the conductive medium is used as an extension of the cathode, so that the conductive medium exists as the cathode in the electrolytic cell for electro-deposition; The post-treatment device is used to remove the conductive medium, and it includes a solvent tank and / or a heating device and / or a refrigeration device and / or a combustion device and / or an atmosphere treatment device and / or a spraying device.

6. The zero-stress electrolytic metal foil system according to claim 5, characterized in that, The system further includes a conveying device for realizing the transportation of the conductive medium.

7. The zero-stress electrolytic metal foil system according to claim 6, characterized in that, The system further includes a pre-treatment device; The pre-treatment device loads the conductive medium on the carrier and / or performs surface treatment on the conductive medium; The carrier moves driven by the conveying device, and carries the conductive medium through the deposition device and the post-treatment device in sequence.

8. The zero-stress electrolytic metal foil system according to claim 7, characterized in that, The pre-treatment device includes a spraying device and / or a brushing device and / or a solvent tank and / or a heating device and / or a refrigeration device and / or a UV curing device.

9. An application of the method according to any one of claims 1 to 4, characterized in that, The method is used to produce metal foil with a thickness dimension ≥ 2 μm, and / or is used to produce large-size metal foil with a length dimension specification ≥ 3 m and a width dimension specification ≥ 1.2 m, and / or is used for continuous production of metal foil rolls.

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