Production equipment and production method of lithium-copper composite belt

Abstract

The embodiment of the invention provides production equipment and a production method of a lithium-copper composite belt. The equipment is applied to the technical field of lithium ion batteries and comprises a first base material lithium composite belt preparation device, a second base material lithium composite belt preparation device, a copper foil unwinding device, an auxiliary film unwinding device, a composite belt roller, an auxiliary film winding device, a base material winding device and a lithium copper composite belt winding device. In this way, through the design of the auxiliary film, the metal lithium layer for transferring the base material lithium to the copper foil can be in a continuous strip shape and can also be a metal lithium layer with interval width in the transverse direction or the longitudinal direction, and the lithium edge is neat; and the first base material lithium composite belt preparation device and the second base material lithium composite belt preparation device are provided with the liquid lubricant coating mechanism and the liquid release agent coating mechanism, so that metal lithium of the base material is easier to transfer to the surface of the copper foil, the copper foil and the base material lithium are not easy to deform in the rolling process, and the success rate of preparation of the lithium-copper composite belt is improved.

Description

Technical Field

[0001] This disclosure relates to the field of lithium-ion battery technology, and in particular to a production equipment and method for lithium-copper composite strips. Background Technology

[0002] With the commercialization of electric vehicles, batteries, as a core component of electric vehicles, are also experiencing faster development and a greater demand for upgrades. Lithium-ion batteries, due to their advantages such as high energy density, high power density, long lifespan, and no memory effect, occupy a large share of batteries for portable electronic products and power batteries. Lithium metal, with its extremely negative potential and very high specific capacity (3860 mAh / g), has become an excellent choice for high-energy-density lithium batteries, and composite products of lithium metal and copper foil are emerging as a new direction for upgrading negative electrodes.

[0003] Currently, the main technical solutions for preparing lithium-copper composite anodes (lithium-copper composite strips with lithium on both sides) include mechanical composite preparation and preparation by physical vapor deposition. Among them, mechanical composite preparation is popular because it is simple and inexpensive. However, the bonding force between lithium metal and copper foil is poor. Low rolling pressure can easily cause the lithium-copper composite strip to be weakly bonded and easily fall off, while high rolling pressure can easily cause wrinkles and cracks to form between the lithium metal and copper foil. Existing mechanical composite preparation methods cannot solve the above problems. Therefore, there is an urgent need for a mechanical composite preparation method that can effectively control the rolling pressure of lithium metal and copper, so that lithium and copper foil can be well bonded during mechanical pressure composite process. Summary of the Invention

[0004] This disclosure provides a lithium-copper composite strip production equipment and production method, which solves the technical problem that the combination of metallic lithium and copper foil is prone to wrinkles and cracks when using existing mechanical composite preparation methods. It can effectively improve the bonding force between metallic lithium and copper, so that lithium and copper foil can be perfectly combined.

[0005] According to a first aspect of the present disclosure, a production equipment for lithium-copper composite strip is provided, comprising a first substrate lithium composite strip preparation device, a second substrate lithium composite strip preparation device, a copper foil unwinding device, an auxiliary film unwinding device, a composite strip roll, an auxiliary film winding device, a substrate winding device, and a lithium-copper composite strip winding device.

[0006] The substrate winding device includes a first substrate winding mechanism and a second substrate winding mechanism. The first substrate winding mechanism is located in front of the lithium-copper composite strip winding device, and the second substrate winding mechanism is located behind the lithium-copper composite strip winding device.

[0007] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the first substrate lithium composite strip preparation apparatus includes: a first lithium strip unwinding mechanism, a first substrate unwinding mechanism, a first intermediate substrate unwinding mechanism, a first intermediate substrate winding mechanism, and a first roll;

[0008] The first substrate unwinding mechanism, the first lithium strip unwinding mechanism, and the first intermediate substrate unwinding mechanism are arranged sequentially from top to bottom and are located in front of the first roll, while the first intermediate substrate winding mechanism is located in front of the first roll.

[0009] The second substrate lithium composite strip preparation apparatus includes: a second lithium strip unwinding mechanism, a second substrate unwinding mechanism, a second intermediate substrate unwinding mechanism, a second intermediate substrate winding mechanism, and a second roll;

[0010] The second intermediate substrate unwinding mechanism, the second lithium strip unwinding mechanism, and the second substrate unwinding mechanism are arranged sequentially from top to bottom and are located in front of the second roll, while the second intermediate substrate winding mechanism is located in front of the second roll.

[0011] In addition to the aspects described above and any possible implementations, a further implementation is provided, wherein,

[0012] The first substrate lithium composite strip preparation apparatus further includes a first liquid lubricant coating mechanism, a first liquid release agent coating mechanism, and a first heating mechanism;

[0013] The second substrate lithium composite strip preparation apparatus further includes a second liquid lubricant coating mechanism, a second liquid release agent coating mechanism, and a second heating mechanism.

[0014] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the composite strip roll is disposed behind the first substrate lithium composite strip preparation device, the second substrate lithium composite strip preparation device, the copper foil unwinding device, and the auxiliary film unwinding device, for rolling the auxiliary film, the first substrate-lithium strip, the copper foil, and the lithium-second substrate strip.

[0015] The auxiliary film winding device is located behind the composite strip roller and is used to wind up the rolled auxiliary film to form a first substrate-lithium-copper foil-lithium-second substrate composite strip.

[0016] In addition to the aspects described above and any possible implementation, a further implementation is provided in which the angle between the center line connecting the second substrate winding mechanism and the center line of the lithium-copper composite strip winding device and the horizontal direction is 0-90°, and when the angle is greater than 0°, the first substrate winding mechanism and the second substrate winding mechanism are simultaneously located on the upper or lower side of the lithium-copper composite strip winding device.

[0017] In addition to the aspects and any possible implementations described above, a further implementation is provided, which further includes a correction mechanism; the correction mechanism is respectively disposed between the first substrate lithium composite strip preparation device and the composite strip roll, between the second substrate lithium composite strip preparation device and the composite strip roll, between the auxiliary film unwinding device and the composite strip roll, and between the copper foil unwinding device and the composite strip roll.

[0018] According to a second aspect of this disclosure, a method for producing lithium-copper composite strip is provided, the method comprising the following steps:

[0019] S1: Prepare the first substrate-lithium composite strip and the lithium-second substrate composite strip respectively;

[0020] S2: The auxiliary film, the first substrate-lithium composite strip, the copper foil and the lithium-second substrate composite strip are rolled together, and the rolled auxiliary film is wound up to prepare the first substrate-lithium-copper foil-lithium-second substrate composite strip.

[0021] S3: Peel the first substrate and the second substrate from the first substrate-lithium-copper foil-lithium-second substrate composite tape to obtain the lithium-copper foil-lithium composite tape.

[0022] In addition to the aspects and any possible implementations described above, a further implementation is provided, wherein in step S1, a first substrate-lithium composite strip and a lithium-second substrate composite strip are prepared by rolling with rolls, the rolling pressure being 0.5-5T; the speed ratio of the two rolls being 1-10; and the rolling temperature being -20℃ to 100℃; in step S2, the rolling pressure being 0.1-2T; the speed ratio of the two rolls being 1; and the rolling temperature being -20℃ to 100℃.

[0023] In addition to the aspects described above and any possible implementations, a further implementation is provided, wherein the method further includes:

[0024] Before being rolled together with lithium metal, the first substrate and the second substrate are coated with a liquid lubricant and then with a liquid release agent. The release agent is then heated and cured to form a coating structure that combines liquid and solid components.

[0025] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the materials of the first substrate and the second substrate are metal, non-metal, composite material of metal and non-metal, or compound material.

[0026] In addition to the aspects described above and any possible implementation, a further implementation is provided in which the auxiliary membrane is a membrane of uniform thickness or a membrane with equally spaced irregularities, the thickness of the auxiliary membrane is greater than 0 mm and less than or equal to 1 mm, and the tensile strength is greater than 90 MPa.

[0027] In addition to the aspects and any possible implementations described above, a further implementation is provided, wherein the concave-convex shaped membrane is provided with concave-convex surfaces at fixed intervals in the transverse or longitudinal direction, the fixed interval distance being 0-1500mm, the concave surface width of the concave-convex surface being 0-50mm, and the concave surface depth of the concave-convex surface being 0-500μm.

[0028] The uneven surface can be provided on one or both sides of the auxiliary membrane.

[0029] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the fixed interval distance is 100-350mm, the concave width of the convex and concave surfaces is 10-30mm, and the concave depth of the convex and concave surfaces is 3-100μm.

[0030] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the thickness of the first substrate, the second substrate, and the intermediate substrate is 1-500 μm; and the thickness of the lithium strip is 0.5-2 mm, and the width is 10-500 mm.

[0031] In addition to the aspects and any possible implementations described above, a further implementation is provided, wherein the peel strength of the first substrate and the second substrate after being coated with lubricant and release agent and cured is 0-50 N / m.

[0032] The present invention discloses the following technical effects:

[0033] (1) By designing the arrangement of the winding device, this invention can avoid wrinkles, cracks and other issues during the winding process of lithium copper composite strip. At the same time, when this product is used as a battery negative electrode, there will be no risk of battery short circuit. Meanwhile, the metallic lithium transferred to the copper foil can be continuous or at fixed intervals.

[0034] (2) The present invention prepares lithium metal layers with different thickness requirements by coating liquid lubricant and release agent on the surface of substrate and curing them, and with the help of auxiliary film, the lithium metal of the substrate is more easily transferred to the surface of copper foil, and the copper foil and the substrate lithium are less prone to deformation during the rolling process, thereby improving the success rate of lithium copper composite strip preparation.

[0035] (3) Through the design of the auxiliary film, the present invention enables the lithium metal layer transferred from the substrate lithium to the copper foil to be a continuous strip shape, or a lithium metal layer with a spacing width in the horizontal or vertical direction, and the edges of the lithium layer are neat.

[0036] It should be understood that the description in the Summary of the Invention is not intended to limit the key or essential features of the embodiments of this disclosure, nor is it intended to restrict the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0037] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. The drawings are provided for a better understanding of the invention and are not intended to limit the scope of this disclosure. In the drawings, the same reference numerals denote the same elements, wherein:

[0038] Figure 1 A structural diagram of a lithium-copper composite strip production apparatus according to an embodiment of the present disclosure is shown, wherein: 1. a first substrate lithium composite strip preparation apparatus; 11. a first lithium strip unwinding mechanism; 12. a first substrate unwinding mechanism; 13. a first intermediate substrate unwinding mechanism; 14. a first liquid lubricant coating mechanism; 15. a first liquid release agent coating mechanism; 16. a first heating mechanism; 17. a first intermediate substrate winding structure; 18. a first roller; 2. a second substrate lithium composite strip preparation apparatus; 21. a second lithium strip unwinding mechanism. 22. Second substrate unwinding mechanism; 23. Second intermediate substrate unwinding mechanism; 24. Second liquid lubricant coating mechanism; 25. Second liquid release agent coating mechanism; 26. Second heating mechanism; 27. Second intermediate substrate winding structure; 28. Second roller; 3. Copper foil unwinding device; 4. Auxiliary film unwinding device; 5. Composite belt roller; 6. Auxiliary film winding device; 7. Substrate winding device; 71. First substrate winding mechanism; 72. Second substrate winding mechanism; 8. Composite belt winding device; 9. Straightening mechanism;

[0039] Figure 2 A schematic diagram of a first substrate-lithium composite strip structure according to an embodiment of the present disclosure is shown;

[0040] Figure 3 shows a schematic diagram of the auxiliary membrane structure according to an embodiment of the present disclosure, wherein Figure 3(a) shows a schematic diagram of the longitudinal section of the auxiliary membrane in this embodiment, and Figure 3(b) shows a schematic diagram of the transverse section of the auxiliary membrane in this embodiment;

[0041] Figure 4 This embodiment shows a schematic diagram of a production method for producing lithium-copper composite strips.

[0042] Figure 5 A schematic diagram of the structure of a lithium-copper composite strip prepared by a lithium-copper composite strip production apparatus according to an embodiment of the present disclosure is shown.

[0043] Figure 6 A schematic diagram of a composite belt structure passing through composite belt rolls according to an embodiment of the present disclosure is shown. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0045] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] Please refer to the appendix. Figure 1 The present invention provides a production equipment for lithium-copper composite strip, including a first substrate lithium composite strip preparation device 1, a second substrate lithium composite strip preparation device 2, a copper foil unwinding device 3, an auxiliary film unwinding device 4, a composite strip roller 5, an auxiliary film winding device 6, a substrate winding device 7, and a lithium-copper composite strip winding device 8.

[0047] The substrate winding device 7 includes a first substrate winding mechanism 71 and a second substrate winding mechanism 72. The first substrate winding mechanism 71 is located in front of the lithium copper composite strip winding device 8, and the second substrate winding mechanism 72 is located behind the lithium copper composite strip winding device 8.

[0048] This embodiment solves the technical problem of wrinkles and cracks forming when lithium metal and copper foil are combined using existing mechanical composite preparation methods. It can effectively improve the bonding force between lithium metal and copper, so that lithium and copper foil can be perfectly bonded.

[0049] Preferably, in some embodiments, the first substrate lithium composite strip preparation device 1 is located above the second substrate lithium composite strip preparation device 2, and prepares the first substrate-lithium composite strip and the lithium-second substrate composite strip respectively and conveys them to the composite strip roll 5 for rolling;

[0050] The first substrate lithium composite strip preparation device 1 includes: a first lithium strip unwinding mechanism 11, a first substrate unwinding mechanism 12, a first intermediate substrate unwinding mechanism 13, a first intermediate substrate winding mechanism 17, and a first roll 18. Specifically, the first substrate unwinding mechanism 12, the first lithium strip unwinding mechanism 11, and the first intermediate substrate unwinding mechanism 13 are arranged sequentially from top to bottom and are located in front of the first roll 18, while the first intermediate substrate winding mechanism 17 is located behind the first roll 18. The first substrate unwinding mechanism 12, the first lithium strip unwinding mechanism 11, and the first intermediate substrate unwinding mechanism 13 respectively transmit the first substrate, the lithium strip, and the intermediate substrate to the first roll 18 for rolling, and the first intermediate substrate winding mechanism 17 winds up the intermediate substrate after it has been rolled by the first roll 18 to form the first substrate-lithium composite strip.

[0051] The second substrate lithium composite strip preparation apparatus 2 includes a second lithium strip unwinding mechanism 21, a second substrate unwinding mechanism 22, a second intermediate substrate unwinding mechanism 23, a second intermediate substrate winding mechanism 27, and a second roll 28. Specifically, the second intermediate substrate unwinding mechanism 23, the second lithium strip unwinding mechanism 21, and the second substrate unwinding mechanism 22 are arranged sequentially from top to bottom and are located in front of the second roll 28, while the second intermediate substrate winding mechanism 27 is located behind the second roll 28. The second substrate unwinding mechanism 22, the second lithium strip unwinding mechanism 21, and the second intermediate substrate unwinding mechanism 23 respectively transmit the second substrate, the lithium strip, and the intermediate substrate to the second roll 28 for rolling, and the second intermediate substrate winding mechanism 27 winds up the intermediate substrate after it has been rolled by the second roll 28 to form a lithium-second substrate composite strip.

[0052] Preferably, in some embodiments, the composite strip roller 5 is disposed behind the first substrate lithium composite strip preparation device 1, the second substrate lithium composite strip preparation device 2, the copper foil unwinding device 3 and the auxiliary film unwinding device 4, for rolling the auxiliary film, the first substrate-lithium strip, the copper foil, and the lithium-second substrate strip. The auxiliary film winding device 6 is disposed behind the composite strip roller 5 for winding the rolled auxiliary film to form the first substrate-lithium-copper foil-lithium-second substrate composite strip.

[0053] The copper foil unwinding device 3 and the auxiliary film unwinding device 4 respectively convey the copper foil and the auxiliary film to the composite strip roller 5 for rolling. The composite strip roller 5 rolls the conveyed auxiliary film, the first substrate-lithium composite strip, the copper foil, and the lithium-second substrate composite strip. At the same time, the auxiliary film winding device 6 winds up the rolled auxiliary film to form the first substrate-lithium-copper foil-lithium-second substrate composite strip. The materials of the first substrate and the second substrate can be the same or different, depending on the actual production needs.

[0054] In this embodiment, during the rolling process of the first substrate-lithium composite strip, copper foil, lithium-second substrate composite strip, and auxiliary film, the auxiliary film can absorb part of the rolling pressure, reduce the deformation of the copper foil, and the width of the auxiliary film is exactly smaller than the width of the lithium layer on the substrate. The lithium layer thickness at the edge of the substrate is not transferred to the copper foil, but only the lithium layer of the auxiliary film width is transferred to the copper foil. The lithium layer edge is neat, the auxiliary film can be reused, and there is no loss.

[0055] The substrate winding device 7 and the lithium-copper composite tape winding device 8 work together to peel the first substrate and the second substrate from the first substrate-lithium-copper foil-lithium-second substrate composite tape and then wind them into the substrate winding device 7, so that the resulting lithium-copper foil-lithium composite tape is wound into the lithium-copper composite tape winding device 8.

[0056] According to the above embodiments of the present invention, by arranging the winding device, wrinkles and cracks can be avoided during the winding process of the lithium copper composite strip. At the same time, when the formed lithium copper composite strip is used as the negative electrode of the battery, there will be no risk of battery short circuit. Meanwhile, the metallic lithium transferred to the copper foil can be continuous or at fixed intervals.

[0057] Preferably, in some embodiments, the first substrate lithium composite strip preparation apparatus 1 further includes a first liquid lubricant coating mechanism 14, a first liquid release agent coating mechanism 15, and a first heating mechanism 16 disposed between the first substrate unwinding mechanism 12 and the first roll 18; specifically, the first substrate released by the first substrate unwinding mechanism 12 is coated with lubricant and release agent by the first liquid lubricant coating mechanism 14 and the first liquid release agent coating mechanism 15 respectively, and the release agent is heated and cured by the first heating mechanism 16 to form a coating structure combining liquid lubrication and solid lubrication, and then conveyed to the first roll 18 for rolling.

[0058] The second substrate lithium composite strip preparation apparatus 2 further includes a second liquid lubricant coating mechanism 24, a second liquid release agent coating mechanism 25, and a second heating mechanism 26 disposed between the second substrate unwinding mechanism 22 and the second roll 28. Specifically, the second substrate released by the second substrate unwinding mechanism 22 is coated with lubricant and release agent by the second liquid lubricant coating mechanism 24 and the second liquid release agent coating mechanism 25 respectively, and the release agent is heated and cured by the second heating mechanism 26 to form a coating structure combining liquid lubrication and solid lubrication, and then conveyed to the second roll 28 for rolling.

[0059] In this embodiment, the first substrate lithium composite strip preparation device 1 and the second substrate lithium composite strip preparation device 2 are equipped with a liquid lubricant coating mechanism and a liquid release agent coating mechanism, which makes it easy to transfer the metallic lithium of the substrate to the copper foil surface without the need for large rolling pressure, so that the copper foil and the substrate lithium are not easily deformed during the rolling process, thereby improving the success rate of lithium copper composite strip preparation.

[0060] like Figure 2 As shown, in this embodiment, the first substrate-lithium composite strip has a lithium layer thinning region of a certain width at the edge of the first substrate and the lithium layer. The structure of the lithium-second substrate composite strip is the same as that of the first substrate-lithium composite strip, and will not be described again.

[0061] Optionally, in some embodiments, as shown in Figure 3, the thickness of the auxiliary film in this embodiment can be a uniform thickness throughout the roll, or it can be designed as a concave-convex shape with a fixed horizontal or vertical spacing of L (mm) (the distance L can be set according to requirements). Specifically, the concave-convex shape can be designed on one side of the auxiliary film, or it can be designed on both sides of the auxiliary film. The width of the concave surface is X (mm), which can appropriately exceed the height of the battery tab, and the depth of the concave surface is H (mm), thereby preventing the transfer of X mm wide metallic lithium on the lithium substrate to the copper foil. The size of H is 0-500 μm, preferably 3-100 μm; the range of L is 0-1500 mm, preferably 100-350 mm; and the range of X is 0-50 mm, preferably 10-30 mm.

[0062] Specifically, in some embodiments, the substrate winding device 7 includes: a first substrate winding mechanism 71 and a second substrate winding mechanism 72, which respectively peel and wind up the first substrate and the second substrate of the first substrate-lithium-copper foil-lithium-second substrate composite tape.

[0063] The first substrate winding mechanism 71 is positioned in front of the lithium-copper composite strip winding device 8, and the second substrate winding mechanism 72 is positioned behind the lithium-copper composite strip winding device 8. The angle between the line connecting the center of the second substrate winding mechanism 72 and the center of the lithium-copper composite strip winding device 8 and the horizontal direction is 0-90°. When the angle is greater than 0°, the first substrate winding mechanism 71 and the second substrate winding mechanism 72 are simultaneously located above or below the lithium-copper composite strip winding device 8. Preferably, the angle between the line connecting the center of the second substrate winding mechanism 72 and the center of the lithium-copper composite strip winding device 8 and the horizontal direction is 30-90°.

[0064] To ensure that the metal strip and / or auxiliary film can be smoothly fed into the rolls for rolling and to ensure the rolling effect of the lithium-copper composite strip, the lithium-copper composite strip production equipment in this embodiment also includes a correction mechanism 9. The correction mechanism 9 is respectively set between the first substrate lithium composite strip preparation device 1 and the composite strip roll 5, between the second substrate lithium composite strip preparation device 2 and the composite strip roll 5, between the auxiliary film unwinding device 4 and the composite strip roll 5, and between the copper foil unwinding device 3 and the composite strip roll 5, and is used to correct the position of the passing metal strip and / or auxiliary film.

[0065] like Figure 4 As shown, this embodiment also provides a method for producing lithium-copper composite strips, including the following steps:

[0066] S101, Prepare the first substrate-lithium composite strip and the lithium-second substrate composite strip respectively;

[0067] The first lithium strip unwinding mechanism 11, the first substrate unwinding mechanism 12, and the first intermediate substrate unwinding mechanism 13 in the first substrate lithium composite strip preparation apparatus 1 respectively release the metallic lithium strip, the first substrate, and the intermediate substrate.

[0068] The second lithium strip unwinding mechanism 21, the second substrate unwinding mechanism 22, and the second intermediate substrate unwinding mechanism 23 in the second substrate lithium composite strip preparation apparatus 2 respectively release the metallic lithium strip, the second substrate, and the intermediate substrate.

[0069] In this embodiment, the thickness of the lithium metal strip can be selected from 0.5-2mm; the width is 10-500mm; the composition can be pure lithium, or a compound of lithium and other metals or non-metals.

[0070] The materials of the first substrate, second substrate, and intermediate substrate can be metal, non-metal, metal / non-metal, or metal / metal layered composite materials. Metal substrate materials include elemental metals or alloys, such as copper, nickel, aluminum, iron, gold, silver, magnesium, cobalt, titanium, niobium, etc. Alloy materials can include aluminum alloys, magnesium alloys, titanium alloys, etc. Non-metallic materials can be polymer films such as polyethylene, polypropylene, and polyethylene terephthalate. Metal / non-metal or metal / metal layered composite materials can include copper-PET layer composite tapes, copper-aluminum layer composite tapes, nickel-titanium layer composite tapes, copper-niobium layer composite tapes, etc. The thickness of each of the first substrate, second substrate, and intermediate substrate can be 1-500 μm. The thickness of the first substrate and second substrate can be the same or different, depending on the specific requirements.

[0071] Preferably, after the first substrate is released by the first substrate unwinding mechanism 12, it first passes through the first liquid lubricant coating mechanism 14 to coat its surface with liquid lubricant, then passes through the first liquid release agent coating mechanism 15 to coat with release agent, and then the release agent is heated and cured by the first heating mechanism 16.

[0072] After the second substrate is released by the second substrate unwinding mechanism 22, it first passes through the second liquid lubricant coating mechanism 24 to coat its surface with liquid lubricant, then passes through the second liquid release agent coating mechanism 25 to coat with release agent, and then passes through the second heating mechanism 26 to heat and cure the release agent.

[0073] The thickness of the liquid lubricant coating is greater than 0 μm and less than or equal to 10 μm, and the liquid lubricant does not react with metallic lithium. The liquid release agent is a commercially available type, but it does not react with metallic lithium. The curing method can be heat curing or ultraviolet light curing. The thickness of the release agent is 1-10 μm. After the substrate is coated with lubricant and cured with release agent, the peel strength between the substrate and the lithium layer is greater than 0 N / m and less than or equal to 50 N / m.

[0074] In this embodiment, the selected lubricant may be one or more mixtures of anhydrous oils, anhydrous esters, and anhydrous ethers; anhydrous oils include at least one of industrial white oil, volatile silicone oil, dimethyl silicone oil, diethyl silicone oil, and kerosene; anhydrous esters include at least one of dimethyl carbonate, propylene carbonate, butenyl carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, and ethyl propionate; anhydrous ethers include one or more of dihexyl ether, tetrahydrofuran, and triethylene glycol dimethyl ether.

[0075] The release agent can be one of the following: silicone release agent, non-silicone release agent, UV radiation release agent, or fluorinated release agent.

[0076] In addition, the surface of the intermediate substrate itself can be coated with liquid lubricant or release agent (which can be cured or not cured), or both lubricant and release agent can be coated at the same time.

[0077] In this embodiment, a liquid lubricating film is first formed on the surfaces of the first and second substrates. A liquid release agent is then applied on top of the liquid lubricant, and the liquid release agent is cured. The curing can be either full curing or semi-curing. This results in a liquid lubrication + solid lubrication system on the substrate surface. By controlling the lubrication of the substrate surface, the metallic lithium in the substrate can be more easily transferred to the copper foil surface. The copper foil and the lithium substrate are less prone to deformation during the rolling process, thus improving the success rate of lithium-copper composite strip preparation.

[0078] After curing, the first substrate, lithium strip, and intermediate substrate are rolled together in the first roll 18, and the second substrate, lithium strip, and intermediate substrate are rolled together in the second roll 28. The rolling pressure is 0.5-5T; the speed ratio of the two rolls is 1-10; the rolling temperature is between -20℃ and 100℃, with a preferred temperature range of 30-40℃. After rolling, the intermediate substrate is wound up by the first intermediate substrate winding mechanism 17 and the second intermediate substrate winding mechanism 27 to form the first substrate-lithium composite strip and the lithium-second substrate composite strip.

[0079] S102. The auxiliary film, the first substrate-lithium composite tape, the copper foil and the lithium-second substrate composite tape are rolled together, and the rolled auxiliary film is wound up to prepare the first substrate-lithium-copper foil-lithium-second substrate composite tape.

[0080] In this embodiment, the thickness of the auxiliary film is greater than 0 mm and less than or equal to 1 mm, preferably 50-200 μm. Its material can be a metal, non-metal, metal / non-metal, or metal / metal layered composite material. The metal material can be a single metal or an alloy. Single metals include copper, nickel, aluminum, iron, gold, silver, magnesium, cobalt, titanium, niobium, etc., while alloys include alloys formed from two or more metals such as copper, nickel, aluminum, iron, gold, silver, magnesium, cobalt, titanium, niobium, etc. The non-metal material can be a polymer such as polyethylene, polypropylene, polyethylene terephthalate, etc. The metal / non-metal composite material can be a copper-PET layer composite tape, a copper-PP layer composite tape, etc. The metal / metal composite material can be a two-element or multi-element multi-layer composite tape, such as a copper-aluminum layer composite tape, a nickel-titanium layer composite tape, a copper-niobium layer composite tape, etc. After being rolled by the composite tape roller 5, the auxiliary film is directly wound by the auxiliary film winding device 6. In this embodiment, the tensile strength of the auxiliary film is >90 MPa.

[0081] During the rolling process of the auxiliary film, the first substrate-lithium composite strip, the copper foil, and the lithium-second substrate composite strip, the auxiliary film can absorb part of the rolling pressure, reduce the deformation of the copper foil, and its width is exactly smaller than the width of the lithium on the substrate lithium. This prevents the thinned lithium layer at the edge of the substrate lithium from being transferred to the copper foil; instead, it transfers only the substrate lithium within the width of the auxiliary film to the copper foil, resulting in neat lithium layer edges. Furthermore, the auxiliary film is reusable and has no loss. The lithium-copper composite strip prepared using the auxiliary film is as follows: Figure 5 As shown.

[0082] In addition, the copper foil in this embodiment can be pure copper foil, copper alloy, or copper layered composite tape with other metals or non-metals. The copper alloy includes one or more elements such as carbon, silicon, lithium, aluminum, magnesium, zinc, nickel, titanium, niobium, and molybdenum. The copper composite tape can be a layered composite tape formed by copper with one or more of the metals such as aluminum, magnesium, zinc, nickel, titanium, niobium, and molybdenum, or it can be a composite tape formed by copper and polymer materials, such as copper-PET layered composite tape, copper-PE layered composite tape, copper-PP layered composite tape, etc.

[0083] After the first substrate-lithium composite strip and the lithium-second substrate composite strip are prepared, they are rolled together with the auxiliary film and copper foil into the composite strip roll 5. Preferably, in this embodiment, the rolling pressure of the composite strip roll 5 is 0.1-2T, the speed ratio of the two rolls is 1, and the rolling temperature is between -20℃ and 100℃, with a preferred temperature range of 30-40℃. The specific structure is as follows. Figure 6 As shown.

[0084] S103. The first substrate and the second substrate are peeled off from the first substrate-lithium-copper foil-lithium-second substrate composite tape to obtain the lithium-copper foil-lithium composite tape.

[0085] Since the auxiliary film's function is to determine the shape of the lithium substrate transferred onto the copper foil, and it itself does not adhere to any other strips, the auxiliary film, after passing through the composite strip roller 5, is directly wound separately by the auxiliary film winding device 6 to form a composite product with a first substrate-lithium-copper foil-lithium-second substrate structure. The lithium-copper composite strip, the first substrate, and the second substrate first pass together parallel to each other or at a certain angle (0-60° to the horizontal) through the composite strip roller 5. Then, the first substrate winding mechanism 71, the second substrate winding mechanism 72, and the lithium-copper composite strip winding device 8 work together simultaneously to peel the first substrate and the second substrate from the first substrate-lithium-copper foil-lithium-second substrate composite strip and wind them respectively into the first substrate winding mechanism 71 and the second substrate winding device 8. In the material winding mechanism 72, the formed lithium-copper foil-lithium composite strip is wound into the lithium-copper composite strip winding device 8. In the specific winding process, the first substrate is wound by the first substrate winding mechanism 71, and the remaining lithium-copper composite strip and the second substrate are not separated. This structure can withstand a large tension and can effectively ensure that the lithium-copper composite strip does not deform and ensures its integrity. Then, the lithium-copper composite strip is wound by the lithium-copper composite strip winding device 8 and then the second substrate is wound. This process can ensure that the lithium-copper composite strip does not wrinkle during the winding process. Optionally, in order to ensure a good winding effect, the winding tension of the substrate winding mechanism 7 and the lithium-copper composite strip winding device 8 is set to 40-50N, and the specific setting can be set according to actual needs.

[0086] Example 1

[0087] In this embodiment, the first substrate, the second substrate, and the intermediate substrate are all made of PET film, with a width of 230 mm and a thickness of 30 μm; the lithium metal strip has a width of 200 mm and a thickness of 2 mm.

[0088] Before passing through the first roll 18 and the second roll 28, the side of the first substrate and the second substrate facing the lithium metal strip are coated with a liquid lubricant and a release agent (the liquid lubricant is industrial white oil 10#, and the release agent is silicone release agent SH-630. The liquid lubricant and the release agent are coated on the substrate, and the release agent is cured).

[0089] The intermediate substrate is coated with a release agent, and the peel strength of the release agent is selected to be 15 N / m.

[0090] The first substrate / second substrate, intermediate substrate and lithium metal are rolled together in a rolling mill with a rolling pressure of 2T, a speed ratio of 1 between the two rolls and a rolling temperature of 33℃. The lithium metal is transferred to the first substrate and the second substrate to form a first substrate-lithium composite strip and a lithium-second substrate composite strip with a lithium layer thickness of 50μm.

[0091] The auxiliary film is a copper-PET composite tape with a width of 150mm and a uniform thickness of 200μm.

[0092] The copper foil has a width of 200 mm and a thickness of 6 μm.

[0093] The auxiliary film, the first substrate (lithium), the copper foil, and the lithium-second substrate are rolled on the composite strip roll 5. The rolling pressure is 0.5T, the speed ratio is 1, and the rolling temperature is 36℃. The auxiliary film, the substrate, and the lithium-copper composite product are then wound up separately by the winding mechanism. The angle α between the center connection line of the lithium-copper composite strip winding device 8 and the second substrate winding mechanism 72 and the horizontal direction is 30°.

[0094] Comparative Example 1

[0095] Before passing through the roller 18, neither the first substrate nor the side of the second substrate facing the lithium metal was coated with liquid lubricant or release agent. The rest of the contents and parameters are the same as those in Example 1.

[0096] Results: The absence of liquid lubricant and release agent on the first and second substrates caused the substrates and lithium metal to be directly pressed into a strip that could not be separated. The lithium metal could not form a film on the surfaces of the first and second substrates, and the substrate strip broke after winding.

[0097] Comparative Example 2

[0098] Before passing through the roll 18, the side of the first and second substrates facing the lithium metal strip is coated with liquid lubricant but not with release agent. The rest of the contents and parameters are the same as those in Example 1.

[0099] Results: During the process of bonding the first substrate-lithium composite strip and the lithium-second substrate composite strip with copper foil, metallic lithium could not be successfully transferred to the copper foil. After increasing the rolling pressure, although metallic lithium was transferred to the copper foil, it caused the copper foil to stretch, wrinkle and deform.

[0100] Comparative Example 3

[0101] After passing through the composite strip roller 5, no auxiliary film is added. The composite strip roller 5 rolls the first substrate-lithium composite strip, copper foil, and lithium-second substrate composite strip together. The rest of the contents and parameters are the same as those in Example 1.

[0102] Results: During the rolling process, the copper foil wrinkled and deformed, resulting in an uneven edge of the lithium layer transferred from the substrate lithium to the copper foil, and it was also impossible to form a situation with interspersed metallic lithium. Furthermore, longitudinal groove-like wrinkles appeared on the lithium-copper composite strip after winding.

[0103] Example 2

[0104] In this embodiment, copper foil is selected as the first substrate and the second substrate, with a width of 230mm and a thickness of 20μm. The side of the first substrate and the second substrate facing the lithium metal strip is coated with liquid lubricant and release agent (kerosene is selected as the liquid lubricant, and UV light radiation release agent is selected as the release agent. The release agent is applied to the substrate and then cured).

[0105] The intermediate substrate is selected as PET film, with a width of 230mm and a thickness of 30μm. Its surface contains a release agent, and the peel strength of the release agent is selected as 30N / m.

[0106] The specifications for lithium metal are selected as follows: width 200mm and thickness 1mm; the first substrate / second substrate, intermediate substrate and lithium metal are rolled together in the rolling mill with a rolling pressure of 2T, a speed ratio of 2 between the upper and lower rolls, and a rolling temperature of 34℃. The lithium metal is transferred to the first substrate and the second substrate to form a first substrate-lithium composite strip and a lithium-second substrate composite strip with a lithium layer thickness of 20μm.

[0107] The auxiliary film is made of aluminum foil with a width of 160mm and a thickness of 100μm. The foil is longitudinally set in a concave-convex shape, with the concave surface having a width of 20mm, a depth of 10μm, and a spacing of 100mm between the concave surfaces.

[0108] Copper foil, used as the negative electrode electrolytic foil for lithium batteries, has a width of 200mm and a thickness of 6μm.

[0109] The auxiliary film, the first substrate-lithium composite strip, the copper foil, and the lithium-second substrate composite strip are rolled on the composite strip roll 5. The rolling pressure is 1T, the speed ratio is 1T, and the temperature is 35℃. The auxiliary film, the substrate, and the lithium-copper composite product are then wound up separately by the winding mechanism.

[0110] The angle α between the center connection line of the lithium-copper composite strip winding device 8 and the second substrate winding mechanism 72 and the horizontal direction is 90°.

[0111] Example 3

[0112] The first and second substrates are aluminum foil, with a width of 230 mm and a thickness of 30 μm. The sides of the first and second substrates facing the lithium metal strip are coated with liquid lubricant and release agent (the liquid lubricant is industrial white oil No. 3, and the release agent is a non-silicone release agent, specifically composed of polyethylene resin-based compound, coupling agent and solvent. The release agent is applied to the substrate and then cured).

[0113] The intermediate substrate is made of polyethylene film with a width of 230 mm and a thickness of 30 μm. The surface of the film contains a release agent with a peel strength of 20 N / m.

[0114] The specifications for the lithium metal strip are selected as follows: width 200mm, thickness 0.5mm;

[0115] The first substrate / second substrate, intermediate substrate and lithium metal are rolled together in the rolls. The rolling pressure is 4T, the speed ratio of the upper and lower rolls is 5, and the rolling temperature is 35℃. The lithium metal is transferred to the first substrate and the second substrate to form a first substrate-lithium composite strip and a lithium-second substrate composite strip with a lithium layer thickness of 10μm.

[0116] The auxiliary film is made of aluminum foil with a width of 160mm and a thickness of 100μm. The foil has a concave-convex shape in the transverse direction, with the concave surface having a width of 50mm, a depth of 80μm, and a spacing of 200mm between the concave surfaces.

[0117] Copper foil, which is the negative electrode electrolytic foil for lithium batteries, has a width of 200mm and a thickness of 7μm;

[0118] The auxiliary film, the first substrate-lithium composite strip, the copper foil, and the lithium-second substrate composite strip are rolled on the composite strip roll 5. The rolling pressure is 2T, the speed ratio is 1T, and the rolling temperature is 40℃. The auxiliary film, the first substrate, the second substrate, and the lithium-copper composite strip are wound up separately. The center connection line between the lithium-copper composite strip winding device 8 and the second substrate winding mechanism 72 makes an angle α of 0° with the horizontal direction.

[0119] Therefore, this embodiment prepares lithium metal layers of different thicknesses by coating the substrate surface with liquid lubricant and release agent (curing), and with the auxiliary film, makes it easier for the lithium metal in the substrate to be transferred to the copper foil surface, making the copper foil and substrate lithium less prone to deformation during the rolling process; at the same time, the design of the auxiliary film allows the lithium metal layer transferred from the substrate to the copper foil to be a continuous strip shape, or a lithium metal layer with a gap width in the horizontal or vertical direction, and the edges of the lithium layer are neat. In addition, the arrangement design of the winding shaft can avoid wrinkles and other problems during the winding process of the lithium copper composite strip, thus improving the success rate of lithium copper composite strip preparation.

[0120] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this disclosure is not limited to the described order of actions, because according to this disclosure, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily essential to this disclosure.

[0121] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this disclosure can be achieved, and this is not limited herein.

[0122] The specific embodiments described above do not constitute a limitation on the scope of protection of this disclosure. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A production equipment for lithium copper composite belt, characterized in that: It comprises a first substrate lithium composite strip preparation device (1), a second substrate lithium composite strip preparation device (2), a copper foil unwinding device (3), an auxiliary film unwinding device (4), a composite strip roller (5), an auxiliary film winding device (6), a substrate winding device (7) and a lithium copper composite strip winding device (8); The substrate winding device (7) comprises a first substrate winding mechanism (71) and a second substrate winding mechanism (72); the first substrate winding mechanism (71) is arranged in front of the lithium-copper composite tape winding device (8); and the second substrate winding mechanism (72) is arranged behind the lithium-copper composite tape winding device (8).

2. The production equipment of lithium copper composite belt according to claim 1, characterized in that: The first substrate lithium composite strip preparation device (1) comprises: a first lithium strip unwinding mechanism (11), a first substrate unwinding mechanism (12), a first intermediate substrate unwinding mechanism (13), a first intermediate substrate winding mechanism (17) and a first rolling roller (18); The first substrate unwinding mechanism (12), the first lithium strip unwinding mechanism (11) and the first intermediate substrate unwinding mechanism (13) are arranged in sequence from top to bottom and are located in front of the first roller (18), and the first intermediate substrate winding mechanism (17) is located at the rear of the first roller (18); The second substrate lithium composite strip preparation device (2) comprises: a second lithium strip unwinding mechanism (21), a second substrate unwinding mechanism (22), a second intermediate substrate unwinding mechanism (23), a second intermediate substrate winding mechanism (27) and a second rolling roller (28); The second intermediate substrate unwinding mechanism (23), the second lithium strip unwinding mechanism (21) and the second substrate unwinding mechanism (22) are arranged in sequence from top to bottom and are located on the front side of the second rolling roller (28), and the second intermediate substrate winding mechanism (27) is located on the rear side of the second rolling roller (28).

3. The production equipment of lithium copper composite belt according to claim 2, characterized in that: in, The first substrate lithium composite tape preparation device (1) further comprises a first liquid lubricant coating mechanism (14), a first liquid release agent coating mechanism (15) and a first heating mechanism (16); The second substrate lithium composite belt preparation device (2) further comprises a second liquid lubricant coating mechanism (24), a second liquid release agent coating mechanism (25) and a second heating mechanism (26).

4. The production equipment of lithium copper composite belt according to claim 1, characterized in that: The composite strip rolling roller (5) is arranged at the rear side of the first substrate lithium composite strip preparation device (1), the second substrate lithium composite strip preparation device (2), the copper foil unwinding device (3) and the auxiliary film unwinding device (4), and is used to roll the auxiliary film, the first substrate-lithium strip, the copper foil, and the lithium-second substrate strip. The auxiliary film winding device (6) is arranged at the rear side of the composite strip rolling roller (5) and is used to wind up the rolled auxiliary film to form a first substrate-lithium-copper foil-lithium-second substrate composite strip.

5. The production equipment of lithium copper composite belt according to claim 1, characterized in that: The angle between the center line of the second substrate winding mechanism (72) and the lithium-copper composite tape winding device (8) and the horizontal direction is 0-90°, and when the angle is greater than 0°, the first substrate winding mechanism (71) and the second substrate winding mechanism (72) are simultaneously located on the upper side or the lower side of the lithium-copper composite tape winding device (8).

6. The production equipment of lithium copper composite belt according to claim 1, characterized in that: It also includes a deviation correction mechanism (9); the deviation correction mechanism (9) is respectively arranged between the first substrate lithium composite strip preparation device (1) and the composite strip roller (5), between the second substrate lithium composite strip preparation device (2) and the composite strip roller (5), between the auxiliary film unwinding device (4) and the composite strip roller (5), and between the copper foil unwinding device (3) and the composite strip roller (5).

7. A method for producing a lithium-copper composite strip, which is implemented using the lithium-copper composite strip production equipment according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: S1: preparing a first substrate-lithium composite tape and a lithium-second substrate composite tape respectively; S2: rolling the auxiliary film, the first substrate-lithium composite strip, the copper foil and the lithium-second substrate composite strip together, and rolling up the rolled auxiliary film to prepare a first substrate-lithium-copper foil-lithium-second substrate composite strip; S3: peeling off the first substrate and the second substrate from the first substrate-lithium-copper foil-lithium-second substrate composite tape to obtain a lithium-copper foil-lithium composite tape.

8. The production method according to claim 7, characterized in that: in, In step S1, a first substrate-lithium composite strip and a lithium-second substrate composite strip are prepared by roller rolling, and the rolling pressure is 0.5-5T; the speed ratio of the two rollers is 1-10, and the rolling temperature is -20°C to 100°C; in step S2, the rolling pressure is 0.1-2T, the speed ratio of the two rollers is 1, and the rolling temperature is -20°C to 100°C.

9. The production method according to claim 7, characterized in that: in, The method further comprises: Before rolling with metallic lithium, the first substrate and the second substrate are coated with a liquid lubricant and then with a liquid release agent, and then the release agent is heated and solidified to form a coating structure combining liquid and solid.

10. The production method according to claim 7, characterized in that: The material of the first substrate and the second substrate is metal, non-metal, a composite layer material of metal and non-metal, or a compound material.

11. The production method according to claim 7, characterized in that: The auxiliary film is a film of uniform thickness or a concave-convex film with equal intervals. The thickness of the auxiliary film is greater than 0 mm and less than or equal to 1 mm, and the tensile strength is greater than 90 MPa.

12. The production method according to claim 11, characterized in that: in, The concave-convex film is provided with a concave-convex surface with a fixed interval in the horizontal direction or the vertical direction, the fixed interval distance is 0-1500mm, the concave width of the concave-convex surface is 0-50mm, and the concave depth of the concave-convex surface is 0-500μm; The concavoconvex surface may be provided on one side or both sides of the auxiliary film.

13. The production method according to claim 12, characterized in that: The fixed spacing distance is 100-350 mm, the concave width of the concave-convex surface is 10-30 mm, and the concave depth of the concave-convex surface is 3-100 μm.

14. The production method according to claim 7, characterized in that: The thickness of the first substrate, the second substrate and the intermediate substrate is 1-500 μm; the thickness of the lithium strip is in the range of 0.5-2 mm and the width is 10-500 mm.

15. The production method according to claim 10, characterized in that: in, The peel strength of the first substrate and the second substrate after being coated with a lubricant and a release agent and cured is 0-50 N / m.

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