Lithium metal cutting system for anodes

Abstract

The present disclosure relates to a lithium metal cutting system for a negative electrode, which includes a lithium metal supply unit that supplies lithium metal, a lithium metal transfer unit that transfers the lithium metal supplied from the lithium metal supply unit, and a lithium metal cutting unit that cuts the lithium metal transferred by the lithium metal transfer unit, wherein the lithium metal transfer unit includes a plurality of rollers and a refrigerant pipe disposed inside each of the plurality of rollers.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0132889, filed October 17, 2022, and Korean Patent Application No. 10-2023-0137115, filed October 13, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present disclosure relates to a lithium metal cutting system for anodes, and more particularly, the present disclosure relates to a cutting system that transfers and cuts lithium metal used in anodes and cools the lithium metal during transfer and cutting. [Background technology]

[0003] Lithium metal is used as the negative electrode of lithium secondary batteries, and the manufacturing process of lithium secondary batteries requires a process of cutting the lithium metal to fit the cell size.

[0004] However, lithium metal has low tensile strength at room temperature and tends to adhere to substrates such as molds and knives. When cutting lithium metal, the lithium metal adhered to these substrates must be frequently peeled off, which causes a problem of slowing down the cutting process speed of the lithium metal.

[0005] Furthermore, since the lithium metal attached to the substrate is difficult to peel off, there is a possibility that the lithium metal is wasted in the cutting process, which increases the cost of manufacturing the secondary battery.

[0006] Korean Patent Publication No. 10-2021-0007673 (hereinafter referred to as Patent Document 1) discloses that a temperature control member is installed in a cutting device that cuts lithium metal, preventing lithium from easily adhering to the cutting device, thereby increasing the efficiency of the lithium cutting process and making it easy to cut lithium into the desired shape.

[0007] However, in Patent Document 1, the temperature control member is arranged only in the cutting device, so the problem of lithium metal adhering to rollers and the like during the lithium metal transport process still occurs.

[0008] In addition, in the case of Patent Document 1, the lithium metal must be cooled by a cutting device, but since it is difficult to cool the lithium metal placed on the cutting device in a short time, the lithium metal is not sufficiently cooled unless it is placed on the cutting device for a certain period of time or more. This increases the time required for the lithium metal cutting process, which may cause a problem of a slower cutting process speed. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Korean Patent Publication No. 2021-0007673 (2021.01.20) Summary of the Invention [Problem to be solved by the invention]

[0010] The object of the present invention has been proposed to solve the above problems, and is to provide a lithium electrode manufacturing apparatus and method that can effectively cut lithium metal by cooling the lithium metal to a desired temperature in a short time in the cutting device because the lithium metal is sufficiently cooled when it reaches the cutting device without adhering to rollers or the like during the transportation process. [Means for solving the problem]

[0011] In order to achieve the above-mentioned object of the present invention, a lithium metal cutting system according to one embodiment of the present invention includes a lithium metal supply unit that supplies lithium metal, a lithium metal transfer unit that transfers the lithium metal supplied from the lithium metal supply unit, and a lithium metal cutting unit that cuts the lithium metal transferred by the lithium metal transfer unit, and the lithium metal transfer unit may include a plurality of rollers and a refrigerant pipe disposed inside each of the plurality of rollers.

[0012] In one embodiment, a coolant is supplied to the coolant pipe of each of the plurality of rollers, and the temperature of the coolant may decrease from the lithium metal supply section toward the lithium metal cutting section.

[0013] In one embodiment, the temperature of the refrigerant may be gradually reduced.

[0014] In one embodiment, the lithium metal cutting unit includes a cutting stage, and a cutting coolant pipe may be disposed inside the lithium metal cutting stage.

[0015] In one embodiment, the refrigerant is also supplied to the inside of the cut refrigerant pipe, and the temperature of the refrigerant supplied to the inside of the cut refrigerant pipe may be lower than or the same as the temperature of the refrigerant supplied to the adjacent refrigerant pipe.

[0016] In one embodiment, at least some of the rollers may be positioned at different heights from one another.

[0017] In one embodiment, the lithium metal supply unit includes a take-up roller that takes up the lithium metal, and a coolant can be supplied to the inside of the take-up roller.

[0018] In one embodiment, a refrigerant is supplied to the refrigerant pipe of each of the plurality of rollers, and the refrigerants may have the same temperature.

[0019] In one embodiment, the refrigerant is also supplied to the inside of the cut refrigerant pipe, The temperature of the refrigerant supplied to the inside of the cut refrigerant pipe may be lower than or the same as the temperature of the refrigerant supplied to the adjacent refrigerant pipe. [Effects of the Invention]

[0020] The effect of the present disclosure is that the lithium metal for a negative electrode is cooled during transportation and cutting to increase the tensile strength of the lithium metal, thereby preventing the lithium metal from adhering to the substrate when cutting the lithium metal. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 illustrates a lithium metal cutting system for anodes according to one embodiment of the present invention. [Figure 2] FIG. 1 illustrates a lithium metal cutting system for anodes according to another embodiment of the present invention. [Figure 3] FIG. 10 is a diagram showing a lithium metal cutting system for a negative electrode according to another embodiment of the present invention. [Figure 4] 1 is a photograph of a cut surface of lithium metal according to Comparative Example 1 of the present invention. [Figure 5] 1 is a photograph of a cut surface of lithium metal according to Comparative Example 2 of the present invention. [Figure 6] 1 is a photograph of a cross section of lithium metal according to Example 1 of the present invention. [Figure 7] 1 is a photograph of a cross section of lithium metal according to Example 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] An embodiment of the present invention will be described in detail below. However, the following description should be understood as an example to help understand the present invention, and should not be understood as restricting or limiting the present invention. Furthermore, it goes without saying that the present invention is not limited to the accompanying drawings. Those skilled in the art will be able to embody the present invention in various forms without departing from the technical spirit of the present invention, by referring to the following description and the accompanying drawings.

[0023] negative electrode The negative electrode may contain lithium metal. The negative electrode may be made of pure lithium metal or a lithium alloy, or may be made by coating and drying a negative electrode active material on the lithium metal.

[0024] The lithium metal may include at least one of pure lithium, a lithium alloy, and a lithium metal composite oxide. The lithium alloy may include a metal selected from the group consisting of Al, Mg, K, Na, Ca, Sr, Ba, Si, Ge, Sb, Pb, In, and Zn. The lithium metal composite oxide may include lithium and any one metal (Me) oxide (MeO) selected from the group consisting of Si, Sn, Zn, Mg, Cd, Ce, Ni, and Fe. x ) and as an example, Li x Fe2O3(0<0≦1) or Li x WO2(0 <x≦1)であってもよい。

[0025] The lithium metal of the present invention may have a protective layer, as in the case of conventional lithium metal with an electrolyte. The protective layer may include any material that has lithium ion conductivity, does not interfere with the operation of the battery, and does not react with lithium. Examples include a garnet-type ceramic protective layer, a protective layer made of lithium-substituted polyacrylic acid, and a molybdenum disulfide-based protective layer. Any protective layer that improves the stability of the lithium metal may be used.

[0026] The lithium metal is generally produced with a thickness of 3 μm or more and 500 μm or less. The lithium metal can also form fine irregularities on its surface to strengthen the bonding force between the lithium metal and the negative electrode active material or the solid electrolyte, and can be used in various forms such as films, sheets, foils, nets, porous bodies, foaming agents, non-woven fabrics, etc.

[0027] Examples of the negative electrode active material include carbon such as graphitizable carbon and graphite-based carbon:Li x Fe2O3(0 < 0 ≦ 1), Li x WO2(0 < x ≦ 1), Sn x Me 1-x Me’ y O z (Me: Mn, Fe, Pb, Ge; Me’: Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen; 0 < x ≦ 1; 1 ≦ y ≦ 3; 1 ≦ z ≦ 8) and other metal composite oxides; lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, and Bi2O5; conductive polymers such as polyacetylene; Li-Co-Ni-based materials, etc. can be used.

[0028] solid electrolyte The solid electrolyte may contain at least one or more of sulfide-based solid electrolytes, oxide-based solid electrolytes, and organic solid electrolytes. For the solid electrolyte according to the present invention, particles with a coated or modified surface can be used. Sulfide-based solid electrolytes have advantages compared to other solid electrolytes in terms of ionic conductivity and production cost. Therefore, the present invention will proceed with the description of the examples in which sulfide-based solid electrolytes are used.

[0029] The sulfide-based solid electrolyte has a lithium ion conductivity of 10 -2 ~10 -3The sulfide-based solid electrolyte powder has a high conductivity of 0.15 S / cm, which facilitates the formation of a contact interface between the electrode and the electrolyte, and has the advantages of good mechanical strength and mechanical flexibility. The sulfide-based solid electrolyte powder contains sulfur (S) and has the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and can include Li-PS-based glass and Li-PS-based glass ceramic. The sulfide-based solid electrolyte is not particularly limited in the present invention, and all known sulfide-based materials used in the field of lithium batteries can be used. For example, sulfide-based solid electrolytes include Li6PS5Cl (LPSCl), Thio-LISICON (Li 3.25 Ge 0.25 P 0.75 S4), Li2S-P2S5-LiCl, Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-Li2S-P2O5, LiILi3PO4-P2S5, Li2S-P2S5, Li3PS4, Li7P3S 11 , LiI-Li2S-B2S3, Li3PO4-Li2S-Si2S, Li3PO4-Li2S-SiS2, LiPO4-Li2S-SiS, Li 10 GeP2S 12 , Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 , Li7P3S 11 etc.

[0030] The thickness of the solid electrolyte can be selected depending on the desired battery characteristics. For example, the thickness after densification by pressing can be preferably about 0.1 μm to 1000 μm, more preferably about 1 μm to 100 μm, and even more preferably about 10 μm to 50 μm.

[0031] positive electrode The positive electrode can be manufactured by, for example, applying a positive electrode mixture, which is a mixture of a positive electrode active material composed of positive electrode active material particles, a conductive material, and a binder, to a positive electrode current collector, and a filler can be further added to the positive electrode mixture, if necessary.

[0032] The positive electrode current collector is generally manufactured to a thickness of about 3 μm to 500 μm, and is not particularly limited as long as it does not cause chemical changes in the battery and has high conductivity, and may be made of, for example, stainless steel, aluminum, nickel, titanium, or aluminum or stainless steel surface-treated with carbon, nickel titanium, or silver, or more specifically, aluminum. The current collector may have fine irregularities on its surface to increase the adhesive strength of the positive electrode active material, and may be in various forms such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0033] The positive electrode active material may include, in addition to the positive electrode active material particles, a layered compound such as lithium nickel oxide (LiNiO2) or a compound substituted with one or more transition metals; +x Mn 2-x Lithium manganese oxides such as LiMnO4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, and LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiV3O4, V2O5, and Cu2V2O7; Ni-site lithium nickel oxides represented by the chemical formula LiNi1-xMxO2 (where M=Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x=0.01 to 0.3); 2-x M x The compounds may be composed of, but are not limited to, lithium manganese composite oxides represented by Li2Mn3MO8 (where M=Co, Ni, Fe, Cr, Zn, or Ta, and x=0.01 or more and 0.1 or less) or Li2Mn3MO8 (where M=Fe, Co, Ni, Cu, or Zn); LiMn2O4, in which part of the Li in the chemical formula is replaced with an alkaline earth metal ion; disulfide compounds; Fe2(MoO4)3, etc.

[0034] The conductive material can usually be added in an amount of 0.1 to 30 wt % based on the weight of the entire mixture including the positive electrode active material. Such a conductive material is not particularly limited as long as it does not cause chemical changes in the battery and has conductivity, and examples thereof include graphite such as natural graphite and artificial graphite; carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; conductive fibers such as carbon fiber and metal fiber; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives.

[0035] The binder contained in the positive electrode is a component that aids in binding the active material with the conductive material and the current collector, and is typically added in an amount of 0.1 to 30 wt % based on the total weight of the mixture including the positive electrode active material. The addition of the binder can also enhance the binding strength between the positive electrode and the solid electrolyte. The solid electrolyte can also be distributed within the positive electrode. The binder used in the present invention is not particularly limited, and known methods can be used. The polymer may be any one selected from the group consisting of polyamide-imide (PAI), polyimide (PI), polyamide (PA), polyamic acid, polyethylene oxide (PEO), polystyrene (PS), PEP-MNB (poly(ethylene-copropylene-co-5-methylene-2-norbornene)), VDF (polyvinylidene fluoride), PVDF-HFP (poly(vinylidene fluoride-co-hexafluoropropylene)), PS-NBR (polystyrene nitrile-butadiene rubber), PMMANBR (poly(methacrylate)nitrile-butadiene rubber), and mixtures thereof, or a mixture of two or more thereof.

[0036] The surface of the positive electrode active material may be coated with a material such as LiNbO to form a buffer layer. The buffer layer may be formed with a thickness of 10 nm or less, thereby reducing the interfacial resistance between the positive electrode and the solid electrolyte.

[0037] The above-described structure of the secondary battery is exemplary and is described for the purpose of facilitating understanding of the present disclosure. The present disclosure is directed to cutting the lithium metal used in the negative electrode. Hereinafter, a lithium metal cutting system for a negative electrode according to the present disclosure will be described with reference to the accompanying drawings.

[0038] FIG. 1 is a diagram illustrating a lithium metal cutting system for anodes according to one embodiment of the present invention.

[0039] Referring to FIG. 1, the lithium metal cutting system may include a lithium metal supply unit, a lithium metal transfer unit, and a lithium metal cutting unit. The lithium metal supply unit may include lithium metal (100) and a take-up roller (110) around which the lithium metal (100) is wound. The lithium metal transfer unit may include a first roller (200a), a second roller (200b), and a third roller (200c). A first refrigerant pipe (300a) may be formed inside the first roller (200a), a second refrigerant pipe (300b) may be formed inside the second roller (200b), and a third refrigerant pipe (300c) may be formed inside the third roller (200c). The lithium metal cutting unit may include a cutting member (400) and a cutting stage (500). A cutting refrigerant pipe (510) may be formed inside the cutting stage (500).

[0040] The lithium metal supply unit supplies lithium metal to the lithium metal cutting unit, and the take-up roller (110) can unwind a continuous film of lithium metal that cannot be cut. A refrigerant pipe (not shown) through which a refrigerant flows can be disposed inside the take-up roller (110). This cools the lithium metal wound around the take-up roller (110) and prevents the lithium metal from adhering to the lithium metal transfer unit or the lithium metal cutting unit due to its low tensile strength during the transfer process. That is, the refrigerant flowing through the refrigerant pipe (not shown) inside the take-up roller (110) cools the lithium metal, thereby increasing the tensile strength of the lithium metal.

[0041] The type of the refrigerant is not limited. For example, the refrigerant may include cooling water, liquid nitrogen, and liquid helium. However, this is merely an example, and various materials may be used without limitation as the refrigerant as long as it can cool the lithium metal and increase the tensile strength of the lithium metal.

[0042] The lithium metal transfer unit may transfer the lithium metal supplied from the lithium metal supply unit to the lithium metal cutting unit, thereby transferring a continuous film of lithium metal to the lithium metal cutting unit and cutting it.

[0043] The lithium metal transfer unit can also transfer the lithium metal and simultaneously cool the lithium metal. The first refrigerant pipe (300a), the second refrigerant pipe (300b), and the third refrigerant pipe (300c) can each contain a refrigerant. The first refrigerant pipe (300a), the second refrigerant pipe (300b), and the third refrigerant pipe (300c) can receive the refrigerant through a passage connected to the outside. The refrigerant can include the above-mentioned cooling water, liquid nitrogen, and liquid helium. As described above, the refrigerant can be any of a variety of materials as long as it can cool the lithium metal and increase the tensile strength of the lithium metal.

[0044] The first refrigerant pipe (300a), the second refrigerant pipe (300b), and the third refrigerant pipe (300c) may have different temperatures. For example, the temperature of the refrigerant may decrease from the first refrigerant pipe (300a) to the second refrigerant pipe (300b) and the third refrigerant pipe (300c). The temperatures of the first to third refrigerant pipes (300a, 300b, 300c) may gradually decrease, but the temperatures of the second and third refrigerant pipes (300b, 300c) may be lower than the temperature of the first refrigerant pipe (300a) and may be the same. In addition, the temperatures of the first to third refrigerant pipes (300a, 300b, 300c) may be set without limitation as long as they can cool the lithium metal to a degree that increases its tensile strength.

[0045] The first to third rollers (200a, 200b, 200c) may be disposed at different heights. This allows the film-like lithium metal to be transported while being curved according to the positions of the first to third rollers (200a, 200b, 200c). The lithium metal has low tensile strength and needs to be sufficiently cooled before reaching the lithium metal cutting unit. In the lithium metal cutting system according to the present disclosure, the first to third rollers (200a, 200b, 200c) are disposed at different heights, so that a larger surface area is exposed to the lithium metal transport unit, allowing the lithium metal to be cooled relatively more by the first to third rollers (200a, 200b, 200c).

[0046] However, in an embodiment, the temperatures of the refrigerants supplied to the first to third refrigerant pipes (300a, 300b, 300c) may be the same.

[0047] The lithium metal cutting unit can cut lithium metal transferred in a film form. The lithium metal can be positioned on the cutting stage (500). A cutting coolant pipe (510) is formed within the cutting stage (500), and a coolant can flow through the cutting coolant pipe (510). The cutting coolant pipe (510) can receive the coolant through a passage connected to the outside. The coolant can include the aforementioned cooling water, liquid nitrogen, and liquid helium. As described above, the coolant can be any material as long as it can cool the lithium metal and increase its tensile strength. The cutting coolant pipe (510) can cool the lithium metal again on the cutting stage (500). This increases the tensile strength of the lithium metal on the cutting stage (500). That is, the lithium metal can be cleanly cut by the cutting member (400). Here, "cleanly cut" means that the lithium metal is cut without adhering to the cutting member. The temperature of the coolant flowing through the cut coolant pipe (510) may be lower than or equal to the temperature of the coolant flowing through the coolant pipe of the adjacent roller.

[0048] The cutting member 400 may be any type of cutting tool capable of cutting the lithium metal, such as a knife or a punch press.

[0049] However, in some embodiments, the refrigerant may not be supplied to the lithium metal cutting unit. If the lithium metal is sufficiently cooled in the lithium metal transfer unit to ensure the tensile strength of the lithium metal, the lithium metal transferred to the lithium metal cutting unit may be cut immediately without additional cooling.

[0050] Fig. 2 is a diagram showing a lithium metal cutting system for a negative electrode according to another embodiment of the present invention. Fig. 2 may be substantially the same as Fig. 1 except that five rollers are used. Therefore, a description of the overlapping components will be omitted.

[0051] Referring to FIG. 2, the lithium metal cutting system may include a lithium metal supply unit, a lithium metal transfer unit, and a lithium metal cutting unit. The lithium metal supply unit may include lithium metal (100) and a take-up roller (110) around which the lithium metal (100) is wound. The lithium metal transfer unit may include a first roller (200a), a second roller (200b), a third roller (200c), a fourth roller (200d), and a fifth roller (200e). A first refrigerant pipe (300a) may be formed inside the first roller (200a), a second refrigerant pipe (300b) may be formed inside the second roller (200b), a third refrigerant pipe (300c) may be formed inside the third roller (200c), a fourth refrigerant pipe (300d) may be formed inside the fourth roller (200d), and a fifth refrigerant pipe (300e) may be formed inside the fifth roller (200e). The lithium metal cutting unit may include a cutting member 400 and a cutting stage 500. A cutting coolant pipe 510 may be formed inside the cutting stage 500.

[0052] A refrigerant pipe (not shown) through which a refrigerant flows may be disposed inside the take-up roller 110. This cools the lithium metal wound on the take-up roller 110 and prevents the lithium metal from adhering to each other at the lithium metal supply unit or to the lithium metal transfer unit or the lithium metal cutting unit due to its low tensile strength during the transfer process. In other words, the refrigerant flowing through the refrigerant pipe (not shown) inside the take-up roller 110 cools the lithium metal, thereby increasing the tensile strength of the lithium metal.

[0053] The lithium metal transfer unit can transfer the lithium metal and simultaneously cool the lithium metal. The first to fifth refrigerant pipes (300a, 300b, 300c, 300d, and 300e) can each contain a refrigerant. The first to fifth refrigerant pipes (300a, 300b, 300c, 300d, and 300e) can receive the refrigerant through a passage connected to the outside. The refrigerant can include the above-mentioned cooling water, liquid nitrogen, and liquid helium. In addition, as described above, various materials can be used as the refrigerant without limitation as long as the refrigerant can cool the lithium metal and increase the tensile strength of the lithium metal.

[0054] The first to fifth refrigerant pipes (300a, 300b, 300c, 300d, 300e) may have refrigerants of different temperatures flowing therethrough. For example, the temperature of the refrigerant may decrease from the first refrigerant pipe (300a) to the fifth refrigerant pipe (300e). The temperatures of the first to fifth refrigerant pipes (300a, 300b, 300c, 300d, 300e) may decrease sequentially, or at least some of the refrigerant pipes may have the same temperature. In addition, the temperatures of the first to fifth refrigerant pipes (300a, 300b, 300c, 300d, 300e) may be set without limitation as long as they can be cooled to a degree that increases the tensile strength of the lithium metal.

[0055] The first to fifth rollers (200a, 200b, 200c, 200d, 200e) may be disposed at different heights. This allows the film-like lithium metal to be transported while being curved according to the positions of the first to fifth rollers (200a, 200b, 200c, 200d, 200e). The lithium metal has low tensile strength and needs to be sufficiently cooled before reaching the lithium metal cutting unit. In the lithium metal cutting system according to the present disclosure, the first to fifth rollers (200a, 200b, 200c, 200d, 200e) are disposed at different heights, so that a larger surface area is exposed to the lithium metal transport unit, allowing the lithium metal to be cooled relatively more by the first to fifth rollers (200a, 200b, 200c, 200d, 200e).

[0056] In addition, the embodiment of FIG. 2 has more rollers than the embodiment of FIG. 1, allowing for more cooling of the lithium metal.

[0057] However, in an embodiment, the temperatures of the refrigerants supplied to the first to fifth refrigerant pipes (300a, 300b, 300c, 300d, 300e) may be the same.

[0058] The lithium metal cutting unit can cut lithium metal transferred in a film form. The lithium metal can be positioned on the cutting stage (500). A cutting refrigerant pipe (510) is formed within the cutting stage (500), and a refrigerant can flow through the cutting refrigerant pipe (510). The cutting refrigerant pipe (510) can receive the refrigerant through a passage connected to the outside. The cutting refrigerant pipe (510) can re-cool the lithium metal on the cutting stage (500). This increases the tensile strength of the lithium metal on the cutting stage (500). That is, the lithium metal can be cleanly cut by the cutting member (400). Here, "cleanly cut" means that the lithium metal is cut without adhering to the cutting member. The temperature of the refrigerant flowing through the cutting refrigerant pipe (510) can be lower than or equal to the temperature of the refrigerant flowing through the refrigerant pipe of the adjacent roller.

[0059] The cutting member 400 may be any type of cutting tool capable of cutting the lithium metal, such as a knife or a punch press.

[0060] Fig. 3 is a diagram showing a lithium metal cutting system for a negative electrode according to another embodiment of the present invention. Fig. 3 may be substantially the same as Figs. 1 and 2, except that first to nth rollers are used. Therefore, a description of the overlapping components will be omitted.

[0061] Referring to Figure 3, the lithium metal cutting system according to the present disclosure is not limited to the number of rollers and can be designed in various ways. The rollers can be freely used within a range that sufficiently cools the lithium metal. For example, first to nth rollers (200a, 200b, ..., 200n) can be used to cool the metallic lithium. The first to nth rollers (200a, ..., 200n) can each include a refrigerant pipe (300a, 300b, ..., 300n).

[0062] The temperature of the refrigerant flowing through the refrigerant pipes (300a, 300b, ..., 300n) may gradually decrease. That is, the temperature of the refrigerant may decrease from the first refrigerant pipe (300a) to the n-th refrigerant pipe (300n).

[0063] For example, if the temperature of the refrigerant in the first refrigerant pipe (300a) is 10°C to -10°C, the temperature of the refrigerant in the nth refrigerant pipe (300n) is set to -40°C to -50°C, but the refrigerant temperature can be set to decrease from the first refrigerant pipe (300a) to the nth refrigerant pipe (300n).

[0064] The lithium metal (100) is preferably cooled to a temperature of about -10°C to -30°C just before being finally cut. As a result, the temperature of the room temperature lithium metal (100) gradually decreases as it is transported by the rollers, and it is preferable that the temperature is between -10°C to -30°C when it reaches the cutting stage (500). The temperature of the lithium metal (100) may be decreased at a certain rate (e.g., a specific percentage) or by a certain range. Any method can be applied as long as the temperature of the lithium metal (100) reaches the temperature range of -10°C to -30°C when it reaches the cutting stage (500).

[0065] If the refrigerant flows only through the cutting stage (500), the cooling time of the lithium metal (100) is short and the lithium metal (100) does not cool down sufficiently. Therefore, when the lithium metal (100) is repeatedly cut, the cut surface is not smooth. If the cooling is carried out through rollers and the lithium metal (100) is transported to the cutting stage (500), the temperature of the lithium metal (100) can be lowered to a desired temperature, and the cut surface can be smooth.

[0066] The present disclosure has been described above by way of example, but this should be understood as being for the purpose of aiding in the understanding of the present disclosure and should not be understood as being for the purpose of limiting the embodiments of the present disclosure. Those skilled in the art will be able to appropriately modify and implement an embodiment and example of the present disclosure, such as by omitting, changing, or replacing all or part of the configuration of an embodiment and example of the present disclosure, or by adding other configurations, without departing from the technical spirit of the present disclosure, by referring to this specification and the accompanying drawings. Therefore, the scope of protection of the present disclosure should be interpreted by the scope of the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of rights of the present disclosure.

[0067] Unless otherwise defined, all terms and expressions used in this specification should be understood in a manner that is commonly understood by a person having ordinary skill in the art to which this disclosure pertains. Furthermore, the terms and expressions used in this specification should be interpreted broadly and not in a restrictive sense.

[0068] In this specification, the word "comprises" does not exclude the presence or addition of one or more other components other than those mentioned.

[0069] Furthermore, in this specification, the singular form includes the plural form unless the context clearly indicates otherwise.

[0070] Preferred examples are shown below to aid in understanding the present invention. However, the following examples are provided to make the present invention easier to understand, and the present invention is not limited thereto.

[0071] [Example] Example 1 Referring to FIG. 1, a lithium metal supply unit including lithium metal (100) and a take-up roller (110) around which the lithium metal (100) was wound was prepared, and then the lithium metal sheet was introduced into a lithium metal transfer unit including a first roller (200a), a second roller (200b), and a third roller (200c). A first refrigerant pipe (300a) was formed inside the first roller (200a), a second refrigerant pipe (300b) was formed inside the second roller (200b), and a third refrigerant pipe (300c) was formed inside the third roller (200c). The refrigerant temperatures of the first refrigerant pipe (300a) were set to -20°C, the second refrigerant pipe (300b) to -30°C, and the third refrigerant pipe (300c) to -40°C. The lithium metal sheet was then transferred to the lithium metal transfer unit at a speed of 1 cm / s. After this, the lithium metal sheet cooled to -20°C was cut with a knife.

[0072] Example 2 The lithium metal sheet was cut in the same manner as in Example 1, except that the refrigerant temperatures of the first refrigerant pipe (300a) to the third refrigerant pipe (300c) were all set to -30°C.

[0073] Comparative Example 1 A lithium metal sheet was cut in the same manner as in Example 1, except that a lithium metal transfer section without a refrigerant pipe was used and no cooling step was performed.

[0074] Comparative Example 2 The lithium metal sheet was cut in the same manner as in Example 1, except that instead of using a refrigerant tube, the lithium metal sheet was cooled by immersing it in liquid nitrogen for 10 seconds using a conventional liquid nitrogen cooling method.

[0075] Experimental example 1: Cross-sectional evaluation of lithium metal sheet The cross sections of the lithium metal sheets manufactured in the examples and comparative examples were photographed and are shown in Figures 4 to 7. The upper part of each figure shows a photograph of the upper part of the cut surface taken with an optical microscope, and the lower part shows the illuminance of the lithium metal sheet cross section photographed with a laser optical illuminance meter.

[0076] FIG. 4 shows a cross section of the lithium metal sheet produced in Comparative Example 1 without undergoing the cooling process, and it was confirmed that the cut surface was not smooth.

[0077] FIG. 5 shows a cross section of the lithium metal sheet produced in Comparative Example 2, which was cooled by being supported in liquid nitrogen, and it was confirmed that the cut surface was smooth.

[0078] Figure 6 shows the cross section of the lithium metal sheet produced in Example 1, which was cooled by gradually lowering the temperature of the refrigerant tube. It was confirmed that the cut surface was smoother than that obtained by the conventional liquid nitrogen cooling method.

[0079] FIG. 7 shows the cross section of the lithium metal sheet manufactured in Example 2, which was cooled so that the temperature of the refrigerant pipe was the same. It was confirmed that the cut surface was slightly less smooth than that of Example 1.

[0080] The embodiments described as examples in this specification can be combined with each other, and unless contradictory, the content described in a particular embodiment can be applied to other embodiments as well, even if it is not described in other embodiments. [Explanation of symbols]

[0081] 100: Lithium metal 110: Winding roller 200a, 200b, 200c, 200d, 200e: 1st to 5th rollers 300a, 300b, 300c, 300d, 300e: 1st to 5th refrigerant pipes 400: Cutting material 500: Cutting stage 510: Cutting refrigerant pipe

Claims

1. a lithium metal supply unit that supplies lithium metal; a lithium metal transfer unit that transfers the lithium metal supplied from the lithium metal supply unit; and a lithium metal cutting unit that cuts the lithium metal transferred by the lithium metal transferring unit; The lithium metal transport unit is a plurality of rollers; and A lithium metal cutting system for a negative electrode, comprising a refrigerant pipe disposed inside each of the plurality of rollers.

2. A refrigerant is supplied to the refrigerant pipe of each of the plurality of rollers, The lithium metal cutting system for a negative electrode according to claim 1, wherein the temperature of the coolant decreases from the lithium metal supply unit toward the lithium metal cutting unit.

3. 3. The system for cutting lithium metal for negative electrode according to claim 2, wherein the temperature of the coolant is gradually decreased.

4. the lithium metal cutting unit includes a cutting stage; 3. The system for cutting lithium metal for anode according to claim 2, wherein a cutting coolant pipe is disposed inside the lithium metal cutting stage.

5. The refrigerant is also supplied to the inside of the cut refrigerant pipe, 5. The lithium metal cutting system for anodes according to claim 4, wherein the temperature of the refrigerant supplied to the inside of the cutting refrigerant pipe is lower than or equal to the temperature of the refrigerant supplied to the adjacent refrigerant pipe.

6. The lithium metal cutting system for anodes according to claim 1, wherein at least some of the rollers are arranged at different heights.

7. the lithium metal supply unit includes a take-up roller that takes up the lithium metal, The lithium metal cutting system for anodes according to claim 1, wherein a coolant is supplied inside the winding roller.

8. A refrigerant is supplied to the refrigerant pipe of each of the plurality of rollers, The lithium metal cutting system for negative electrodes according to any one of claims 1 to 7, wherein the temperatures of the coolants are the same.

9. The refrigerant is also supplied to the inside of the cut refrigerant pipe, 9. The lithium metal cutting system for anodes according to claim 8, wherein the temperature of the refrigerant supplied to the inside of the cutting refrigerant pipe is lower than or equal to the temperature of the refrigerant supplied to the adjacent refrigerant pipe.

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