A metal foil production apparatus

Abstract

This invention provides a metal foil production apparatus in which the coverage area of ​​the anode plate is smaller than that of the electrolytic cell, forming two transition zones at the liquid outlet positions at both ends of the electrolytic cell. Shielding plates are installed in these transition zones, spaced close to the surface of the cathode roller. The shielding plates are made of conductive material and covered with an insulating layer. In operation, the potential of the shielding plates is lower than or equal to the potential of the cathode roller, effectively isolating the electric field in the area covered by the shielding plates. This prevents the boundary area between the cathode roller and the electrolyte from participating in electrolysis. The metal foil production apparatus provided by this invention, through the shielding plates, confines the actual electrolysis area to the internal region completely wetted by the electrolyte, effectively preventing the boundary area between the cathode roller and the electrolyte from participating in electrolysis. This reduces the risk of dark spot-like surface defects in the produced metal foil, improves the quality of the metal foil, and increases production efficiency.

Description

Technical Field

[0001] This invention relates to the field of metal foil production technology, and in particular to a metal foil production apparatus. Background Technology

[0002] Copper foil refers to extremely thin copper materials, specifically copper and copper alloy sheets with a thickness of less than 200μm. Depending on the production process, industrial copper foil can be divided into rolled copper foil and electrolytic copper foil. Compared to rolled copper foil, which is technically complex and has a smaller application scale, electrolytic copper foil has lower production costs and a larger application scale, making it the main production method for copper foil. Electrolytic copper foil can be further divided into lithium-ion battery copper foil and electronic circuit copper foil, depending on its application field.

[0003] Lithium-ion battery copper foil is generally produced using a continuous roller electrolysis method. During production, surface defects such as dark spots are easily generated due to factors such as the surface condition of the cathode roller, the flow state of the electrolyte, and foam generated by additives. These defects need to be removed through post-processing methods such as grinding. However, post-processing is difficult, which leads to resource waste and reduced production efficiency. In particular, for thinner copper foils below 10μm, reprocessing can easily damage the copper foil. Furthermore, dark spot defects that are not effectively removed will affect the quality of lithium-ion battery copper foil products, thereby affecting the battery performance of lithium-ion batteries, such as battery capacity, energy density, and discharge efficiency, which is detrimental to the healthy development of the lithium-ion battery industry. Summary of the Invention

[0004] Based on this, the purpose of the present invention is to provide a metal foil production apparatus to solve the problem of dark spot-like surface defects that are prone to occur in the electrolytic production of metal foil in the prior art.

[0005] This invention provides a metal foil production apparatus, comprising: a machine base, an electrolytic cell and a cathode roller disposed on the machine base, and an anode plate disposed on the bottom surface of the electrolytic cell, wherein...

[0006] The electrolytic cell is an arc-shaped cell, the cathode roller is at least partially arranged in the electrolytic cell, and the bottom surface of the electrolytic cell is parallel to the surface of the cathode roller. The anode plate is attached to the bottom surface of the electrolytic cell, and the bottom of the electrolytic cell is provided with a liquid inlet.

[0007] The coverage area of ​​the anode plate is smaller than that of the electrolytic cell, so as to form two transition zones at the liquid outlet positions at both ends of the electrolytic cell;

[0008] The transition zone is provided with a shielding plate. The shielding plates are spaced close to the surface of the cathode roller, and the spacing is less than a first preset distance and greater than zero. The shielding plates are made of conductive material and are covered with an insulating layer on the outside. In the working state, the potential of the shielding plate is lower than or equal to the potential of the cathode roller.

[0009] Optionally, an auxiliary field plate is also provided on the anode plate. The auxiliary field plate is made of conductive material and is covered with an insulating layer on the outside. When the first power supply is connected, an auxiliary electric field pointing towards the cathode roller is formed between the auxiliary field plate and the cathode roller.

[0010] The auxiliary field plate includes multiple field plate units, which are elongated strips arranged side by side at intervals, with the arrangement direction consistent with the extension direction of the electrolytic cell.

[0011] Optionally, the device may also include a mesh plate, which has the same layer structure as the shielding plate and is electrically connected to it. The mesh plate extends from the shielding plate and extends to the end of the plate surrounding the anode plate.

[0012] Optionally, the auxiliary field plate further includes a grid plate unit, which is disposed at the liquid inlet of the electrolytic cell.

[0013] Optionally, the porosity of the grid plate unit is greater than or equal to 80%.

[0014] Optionally, the operating current connected to the anode plate is a pulse current.

[0015] Optionally, the auxiliary field plate is attached to the anode plate or is arranged parallel to the anode plate at intervals of less than or equal to 5 mm.

[0016] Optionally, the power access points of the auxiliary field plate and the power access points of the anode plate are staggered.

[0017] Optionally, the height of the top edge of the shielding plate is higher than or equal to the height of the outlet line of the electrolytic cell.

[0018] Optionally, the shielding plate is also provided with a liquid outlet, the position of which is consistent with the height of the liquid outlet line, so as to maintain the flow of electrolyte between the shielding plate and the cathode roller.

[0019] The metal foil production apparatus provided by this invention includes: a machine base, an electrolytic cell and a cathode roller disposed on the machine base, and an anode plate disposed on the bottom surface of the electrolytic cell. The electrolytic cell is an arc-shaped trough. The cathode roller is at least partially arranged in the electrolytic cell, and the bottom surface of the electrolytic cell is parallel to the surface of the cathode roller. The anode plate is attached to the bottom surface of the electrolytic cell, and a liquid inlet is provided at the bottom of the electrolytic cell. The coverage area of ​​the anode plate is smaller than the coverage area of ​​the electrolytic cell, forming two transition zones at the liquid outlet positions at both ends of the electrolytic cell. A shielding plate is provided in each transition zone. A shielding plate, made of conductive material and covered with an insulating layer, is positioned close to the surface of the cathode roller. During operation, the potential of the shielding plate is lower than or equal to that of the cathode roller, effectively isolating the electric field in the area covered by the shielding plate. This prevents the boundary between the cathode roller and the electrolyte from meeting the electrolysis conditions and thus avoiding irregular foaming at the boundary and irregular changes in the boundary due to liquid surface fluctuations. This prevents uncontrollable uniformity of the deposited metal layer at the boundary, which can lead to dark spot-like surface defects. The metal foil production apparatus provided by this invention, through the shielding plate, confines the actual electrolysis area to the completely electrolyte-wetted internal region, effectively preventing the boundary between the cathode roller and the electrolyte from participating in electrolysis. This reduces the risk of dark spot-like surface defects in the produced metal foil, improves metal foil quality, and increases production efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the main structure of the metal foil production device in this invention;

[0021] Figure 2 This is a schematic diagram of the planar unfolded structure of the auxiliary field plate of the metal foil production device in this invention.

[0022] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0023] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0024] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] To address the problem of dark spot-like surface defects that easily occur in the electrolytic production of metal foil in existing technologies, this invention provides a metal foil production apparatus. The anode plate's coverage area is smaller than that of the electrolytic cell, forming two transition zones at the liquid outlet positions at both ends of the electrolytic cell. Shielding plates are installed in these transition zones, spaced close to the surface of the cathode roller. The shielding plates are made of conductive material and covered with an insulating layer. In operation, the potential of the shielding plates is lower than or equal to the potential of the cathode roller, effectively isolating the electric field in the area covered by the shielding plates. This prevents the boundary area between the cathode roller and the electrolyte from participating in electrolysis. By limiting the actual electrolysis area to the completely electrolyte-wetted internal region through the shielding plates, the boundary area between the cathode roller and the electrolyte can be effectively prevented from participating in electrolysis, reducing the risk of dark spot-like surface defects in the produced metal foil, improving metal foil quality, and increasing production efficiency.

[0027] Specifically, such as Figure 1 and Figure 2 As shown, in this embodiment, a roller-type continuous electrolysis method is adopted. The metal foil production device includes: a machine base (not shown in the figure), an electrolytic cell 10 and a cathode roller 21 set on the machine base, and an anode plate 22 set on the bottom surface of the electrolytic cell 10. The cathode roller 21 and the anode plate 22 are generally arranged concentrically to make the distance between the surface of the cathode roller 21 and the surface of the anode plate 22 uniform. After being energized, a uniform electric field can be formed, thereby ensuring the uniformity of the metal foil deposited in each part by electrolysis.

[0028] Corresponding to the cathode roller 21, the electrolytic cell 10 is an arc-shaped groove. The cathode roller 21 is at least partially arranged in the electrolytic cell 10, and the bottom surface of the electrolytic cell 10 is parallel to the surface of the cathode roller 21. The anode plate 22 is attached to the bottom surface of the electrolytic cell 10 to achieve the parallelism between the surfaces of the cathode roller 21 and the anode plate 22. The bottom of the electrolytic cell 10 is provided with a liquid inlet 11. The electrolyte is input into the electrolytic cell 10 through the liquid inlet 11 and discharged from both ends above the electrolytic cell 10. Below the liquid outlet line, the cathode roller 21 is immersed in the electrolyte. After energizing, on the surface of the immersed area, the metal ions in the electrolyte undergo an oxidation-reduction reaction on the surface of the cathode roller 21 and are deposited into a metal foil.

[0029] The cathode roller 21 can be made of materials such as stainless steel or titanium. Among them, titanium is less prone to reaction with various components in the electrolyte, is lightweight, and has low operating and maintenance costs, making it a preferred material. The anode plate 22 can be made of lead, aluminum, or titanium as the base material.

[0030] At the outlet position of the electrolytic cell 10, a baffle 50 is also provided to raise the electrolyte height. The baffle 50 is made of insulating material or is insulated from other electrodes so that the wetting range of the electrolyte on the cathode roller 21 is greater than the coverage range of the anode plate 22. Two transition zones can be formed at the outlet positions at both ends of the electrolytic cell 10. Alternatively, the size of the anode plate 22 can be reduced so that the coverage range of the anode plate is smaller than the coverage range of the electrolytic cell. Similarly, two transition zones can be formed at the outlet positions at both ends of the electrolytic cell. Since electrolysis is not expected to occur in the transition zone, the anode plate is not arranged in the transition zone, which can reduce the arrangement cost of the anode plate.

[0031] To shield the cathode roller in the transition zone, a shielding plate 30 is provided in the transition zone. The shielding plates 30 are spaced close to the surface of the cathode roller 21 to prevent them from contacting the cathode roller 21 and hindering its rotation. The spacing is less than a first preset distance and greater than zero to ensure the shielding effect. The shielding plates 30 are made of conductive material and are covered with an insulating layer to prevent electrolytic reactions from occurring on the surface of the shielding plates 30. In the working state, the potential of the shielding plates 30 is lower than or equal to the potential of the cathode roller 21. As a result, in the transition zone, the cathode roller 21 cannot effectively form a cathode due to the potential difference. No oxidation-reduction reaction occurs on the surface of the cathode roller 21 in the transition zone, thereby effectively preventing uneven deposition of metal ions in the electrolyte at irregular boundaries and the generation of dark spot-like surface defects. Furthermore, when the potential of the shielding plate 30 is lower than that of the cathode roller 21, the electric field it generates can drive metal cations to accumulate towards the shielding plate 30, reducing the concentration of metal cations on the surface of the cathode roller 21, and further reducing the possibility of oxidation-reduction reaction and the formation of dark spot-like surface defects on the surface of the cathode roller 21 in the transition zone.

[0032] Furthermore, in the transition zone, the electrolyte can be pre-wetted to the surface of the cathode roller 21 to prevent bubbles from appearing on the surface of the cathode roller 21, which would affect the quality of subsequent electrolytic foil formation.

[0033] To ensure the shielding effect, the transition zone and the shielding plate 30 can be appropriately lengthened in the rolling direction of the cathode roller 21, thereby increasing the distance between the shielding plate 30 and the cathode roller 21, improving the electrolyte capacity and wetting effect. In other words, to ensure the shielding effect, the smaller the size of the shielding plate 30 in the rolling direction of the cathode roller 21, the smaller the distance between the shielding plate 30 and the cathode roller 21. Simultaneously, to ensure the smooth flow of electrolyte, the effectiveness of the shielding, and the electric field strength when a negative electric field is formed, the first preset distance and the minimum distance should be designed according to the specific viscosity of the electrolyte, and the applied voltage should be selected according to the actual distance. This application does not impose any special limitations on this.

[0034] The width of the shielding plate 30 is the same as the width of the electrolytic cell 10, and is generally slightly larger than the length of the cathode roller 21. Depending on different production needs, the width of the shielding plate 30 can be adapted to ensure the shielding effect on the cathode roller 21.

[0035] In this embodiment, a grid plate 31 is also provided in the transition zone. The grid plate 31 has the same layer structure as the shielding plate 30 and is electrically connected to each other. The grid plate 31 extends from the shielding plate 30 and extends to the end surrounding the anode plate 22. This can reduce the risk of current from the anode plate 22 bypassing the shielding plate 30 and communicating with the cathode roller 21 through a very small area above the shielding plate 30, which could lead to electrolysis at the boundary line.

[0036] Since the transition zone does not participate in electrolysis, but electrolyte is still distributed in it, it will reduce the electrolysis efficiency to a certain extent. In order to ensure production efficiency, in this embodiment, an auxiliary field plate 40 is also provided on the anode plate 22. The auxiliary field plate 40 is made of conductive material and is covered with an insulating layer on the outside. When the first power supply is connected, it is used to form an auxiliary electric field pointing towards the cathode roller 21 between the auxiliary field plate 40 and the cathode roller 21. The metal ions in the auxiliary electrolyte move towards the cathode roller 21, thereby improving the electrolysis efficiency.

[0037] Meanwhile, to avoid shielding of the anode plate 22 by the auxiliary field plate 40, the auxiliary field plate 40 includes multiple field plate units 41. The field plate units 41 are elongated and arranged in parallel with intervals, and the arrangement direction is consistent with the extension direction of the electrolytic cell 10.

[0038] To balance the strength and uniformity of the auxiliary electric field and the density of the output current of the anode plate 22, in an optional embodiment, the gap ratio of the auxiliary field plate 40 is 45% to 55%, and the width W1 of the field plate unit 41 is 5 mm to 15 mm, which can be flexibly designed according to specific needs.

[0039] During production, the auxiliary electric field is continuously present, which can increase the concentration of metal cations on the surface of the cathode roller 21, increase the current density, and increase the foil forming speed. Specifically, in an optional embodiment, pulsed current is preferred. During the current pulse period, the cation concentration on the surface of the cathode roller 21 is rapidly consumed, resulting in fast foil forming speed and high product quality. During the pulse interval period, the cation concentration on the surface of the cathode roller 21 can be rapidly recovered and enriched under the action of the auxiliary electric field. By the next pulse period, the metal ion deposition efficiency can be recovered, thereby avoiding the problem of uneven ion distribution due to insufficient ion distribution recovery speed, which leads to insufficient foil uniformity. This improves the application effect of pulsed current in the continuous electrolytic production of metal foil by roller, and improves production efficiency and product quality.

[0040] Furthermore, under the influence of a stable auxiliary electric field, the enrichment of metal cations on the surface of the cathode roller 21 is more uniform, which can effectively improve the uniformity of metal foil formation and improve the surface quality of the obtained metal foil.

[0041] Furthermore, using pulsed current can reduce the risk of leakage between the shielding plate and the cathode roller due to continuous current action, thus ensuring the electrolytic shielding effect in the transition zone.

[0042] To enhance the effect of the auxiliary electric field, in this embodiment, the auxiliary field plate 40 further includes a grid plate unit 42. The grid plate unit 42 is disposed at the liquid inlet 11 of the electrolytic cell 10 to ensure the continuity of the auxiliary electric field. Since no anode plate is disposed at the liquid inlet 11, only the smoothness of liquid inlet needs to be considered, and the uniformity of the electrolytic current in the width direction of the metal foil does not need to be considered. The auxiliary field plate here can be selected as a grid structure.

[0043] To ensure the effectiveness of electrolyte feeding and avoid the problem of turbulence and bubbles in the input electrolyte caused by the obstruction of the mesh plate unit 42, which would affect the electrolysis effect, in this embodiment, the porosity of the mesh plate unit 42 is greater than or equal to 80%.

[0044] To ensure that metal cations are enriched on the surface of the cathode roller 21, in this embodiment, an auxiliary field plate 40 is attached to the anode plate 22. In an optional embodiment, the auxiliary field plate 40 and the anode plate 22 are arranged in parallel and spaced apart, with a spacing of less than or equal to 5 mm.

[0045] The thickness of the insulation layer of the shielding plate 30 and the auxiliary field plate 40 is related to the electrolysis current and the distance between them and the anode plate 22. In order to avoid the insulation layer being broken down and short-circuiting the cathode roller 21, the thickness of the insulation layer needs to be adapted to the actual configuration of the equipment. This application will not elaborate on this.

[0046] Electrode power connections are typically point-connected. Since electrode plates have a certain size, their potential will radiate outwards along the power connection point. In this embodiment, the power connection points of the auxiliary field plate 40 and the anode plate 22 are staggered, which improves the uniformity of the combined electric field, thereby improving the uniformity of the electrolytic current distribution and enhancing the quality of the metal foil. For example, the power connection points of the anode plate 22 can be located on one side of the electrolytic cell, while the power connection points of the auxiliary field plate 40 can be located on the other side.

[0047] To prevent electricity from passing over the shielding plate 40 and connecting to the cathode roller from above, in an optional embodiment, the height of the top edge of the shielding plate 40 is higher than or equal to the height of the outlet line of the electrolytic cell.

[0048] In the transition zone, the pre-wetting of the cathode roller by the electrolyte will consume the additives in the electrolyte. In order to avoid the consumption of additives affecting the wetting effect, in an optional embodiment, the shielding plate 40 is also provided with a liquid outlet. The position of the liquid outlet is consistent with the height of the liquid outlet line, so as to maintain the flow of electrolyte between the shielding plate 40 and the cathode roller 21 and maintain the wetting pretreatment effect of the electrolyte on the cathode roller 21.

[0049] The metal foil production apparatus provided by this invention restricts the actual electrolysis area to the internal area completely wetted by the electrolyte by using a shielding plate. This effectively prevents the boundary between the cathode roller and the electrolyte from participating in the electrolysis, reduces the risk of dark spot-like surface defects in the produced metal foil, improves the quality of the metal foil, and increases production efficiency.

[0050] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0051] The above-described embodiments are merely illustrative of several specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A metal foil production apparatus, characterized in that, The device comprises a platform, an electrolytic cell and a cathode roller arranged on the platform, and an anode plate arranged on the bottom surface of the electrolytic cell, wherein The electrolytic cell is an arc-shaped cell, the cathode roller is arranged at least partially in the electrolytic cell, the bottom surface of the electrolytic cell is parallel to the surface of the cathode roller, the anode plate is attached to the bottom surface of the electrolytic cell, and the bottom of the electrolytic cell is provided with a liquid inlet; The coverage of the anode plate is less than that of the electrolytic cell, so as to form two transition zones at the liquid outlet positions at both ends of the electrolytic cell; The transition zones are provided with shielding plates, the shielding plates are arranged in close proximity to the surface of the cathode roller with a spacing less than a first preset distance and greater than zero, the shielding plates are made of conductive material and are coated with an insulating layer on the outer layer, and in the working state, the potential of the shielding plates is lower than or equal to the potential of the cathode roller, so as to limit the actual electrolysis area to the internal area fully soaked by the electrolyte and avoid the participation of the position of the division line between the cathode roller and the electrolyte in electrolysis.

2. The metal foil production device according to claim 1, wherein The anode plate is further provided with an auxiliary field plate, the auxiliary field plate is made of conductive material and is coated with an insulating layer on the outer layer, and when connected to a first power supply, the auxiliary field plate forms an auxiliary electric field directed to the cathode roller between the auxiliary field plate and the cathode roller; The auxiliary field plate comprises a plurality of field plate units, the field plate units are long strips and are arranged in parallel with a spacing, and the arrangement direction is consistent with the extension direction of the electrolytic cell. The device further comprises a grid plate, the grid plate has the same layer structure as the shielding plate and is electrically connected to each other, the grid plate is extended from the shielding plate and extends to the end surrounding the anode plate.

3. The metal foil production apparatus according to claim 1, wherein The auxiliary field plate further comprises a grid plate unit, and the grid plate unit is arranged at the liquid inlet of the electrolytic cell.

4. The metal foil production apparatus according to claim 2, wherein The porosity of the grid plate unit is greater than or equal to 80%.

5. The metal foil production apparatus according to claim 4, wherein The working current connected to the anode plate is pulse current.

6. The metal foil production apparatus according to claim 2, wherein The auxiliary field plate is attached to the anode plate or is arranged in parallel with a spacing less than or equal to 5 mm.

7. The metal foil production apparatus according to claim 2, wherein The power supply connection points of the auxiliary field plate and the power supply connection points of the anode plate are staggered.

8. The metal foil production apparatus according to claim 2, wherein The top edge height of the shielding plate is higher than or equal to the height of the liquid outlet line of the electrolytic cell.

9. The metal foil production apparatus according to claim 1, wherein The shielding plate is further provided with a liquid outlet, and the setting position of the liquid outlet is consistent with the height of the liquid outlet line, so as to maintain the flowability of the electrolyte between the shielding plate and the cathode roller.

10. The metal foil production apparatus according to claim 9, wherein ​

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