Lithium metal cutting system for negative electrode

Abstract

The present disclosure relates to a lithium metal cutting system for a negative electrode, the system comprising: a lithium metal supply unit for supplying lithium metal; a lithium metal transport unit for transporting the lithium metal supplied from the lithium metal supply unit; and a lithium metal cutting unit for cutting the lithium metal conveyed by the lithium metal conveying unit, in which the lithium alloy conveying unit includes a plurality of rollers and a refrigerant tube provided inside each of the plurality of rollers.

Description

Technical Field

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2022-0132889 filed on October 17, 2022 and Korean Patent Application No. 10-2023-0137115 filed on October 13, 2023, and the entire contents of which are incorporated as part of this specification.

[0002] The present invention relates to a lithium metal cutting system for a negative electrode, and more particularly, the present invention relates to a cutting system for conveying and cutting lithium metal used in a negative electrode and for cooling the lithium metal during conveying and cutting. Background Art

[0003] Lithium metal is used as the negative electrode in lithium-ion batteries, and in the process of manufacturing lithium-ion batteries, it is necessary to cut the lithium metal into battery cell sizes.

[0004] However, lithium metal has low tensile strength at room temperature and easily adheres to materials such as molds or cutters, so when lithium metal is cut, the lithium metal adhered to these materials must be frequently removed, which slows down the lithium metal cutting process.

[0005] In addition, since lithium metal adhered to the material is difficult to remove, there is a problem of wasting lithium metal in the lithium metal cutting process, which increases the cost of manufacturing secondary batteries.

[0006] Korean Patent Application Publication No. 10-2021-0007673 (hereinafter, “Citation 001”) discloses installing a temperature control member on a cutting device for cutting lithium metal to prevent lithium from easily adhering to the cutting device, thereby improving the efficiency of the lithium cutting process and cutting lithium into a desired shape.

[0007] However, Citation 001 discloses that the temperature control member is only disposed in the cutting device of Citation 001, and thus the problem of lithium metal sticking to the rollers and the like still occurs during the conveying process of lithium metal.

[0008] In addition, according to reference 001, the lithium metal needs to be cooled by the cutting device, but it is difficult to cool the lithium metal placed on the cutting device in a short time, so the lithium metal may need to be placed on the cutting device for a period of time before it can be fully cooled. As a result, the time of the lithium metal cutting process increases, which may cause the lithium metal cutting process to slow down.

[0009] [Patent References]

[0010] (Patent Document 1) Korean Patent Application Publication No. 10-2021-0007673 (Publication Date: January 20, 2021) Summary of the invention

[0011] Technical issues

[0012] The object of the present invention proposed to solve the above-mentioned problems is to provide a device for manufacturing a lithium electrode and a method for manufacturing a lithium electrode, which are used to effectively cut lithium metal, wherein in the process of conveying the lithium metal, the lithium metal does not adhere to rollers, etc., and when the lithium metal reaches the cutting device, the lithium metal is sufficiently cooled so that the lithium metal is cooled to a desired temperature in the cutting device in a short time.

[0013] Technical Solution

[0014] In order to achieve the above-mentioned purpose of the present invention, a lithium metal cutting system according to one embodiment of the present invention may include: a lithium metal supply unit for providing lithium metal; a lithium metal transport unit, the lithium metal transport unit is used to transport the lithium metal provided from the lithium metal supply unit; and a lithium metal cutting unit, the lithium metal cutting unit is used to cut the lithium metal transported by the lithium metal transport unit, wherein the lithium metal transport unit includes a plurality of rollers and a refrigerant pipe arranged in each of the plurality of rollers.

[0015] In one embodiment, the refrigerant pipe of each of the plurality of rollers is provided with a refrigerant, and a temperature of the refrigerant may be reduced from the lithium metal supplying part toward the lithium metal transporting part.

[0016] In one embodiment, the temperature of the refrigerant may be gradually decreased.

[0017] In one embodiment, the lithium metal cutting part may include a cutting table, and the cutting refrigerant pipe may be disposed within the lithium metal cutting table.

[0018] In one embodiment, the refrigerant is also supplied to the inside of the cut refrigerant tube, and the temperature of the refrigerant supplied to the inside of the cut refrigerant tube may be lower than or equal to the temperature of the refrigerant supplied to the adjacent refrigerant tube.

[0019] In one embodiment, at least some of the plurality of rollers may be disposed at different heights.

[0020] In one embodiment, the lithium metal supplier includes a winding roller for winding the lithium metal, and the refrigerant may be provided to an interior of the winding roller.

[0021] In one embodiment, the refrigerant pipe of each of the plurality of rollers is provided with a refrigerant, and the refrigerants may have the same temperature as each other.

[0022] In one embodiment, the refrigerant is also provided to the cut refrigerant tube, and

[0023] The temperature of the refrigerant supplied to the inside of the cut refrigerant tube may be lower than or equal to the temperature of the refrigerant supplied to the adjacent refrigerant tube.

[0024] Effects of the Invention

[0025] The present invention has the effect of improving the tensile strength of lithium metal by cooling lithium metal during the transfer and cutting of lithium metal for negative electrode so that the lithium metal does not adhere to the material when the lithium metal is cut. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 : is a diagram illustrating a lithium metal cutting system for a negative electrode according to one embodiment of the present invention.

[0027] Figure 2 : is a diagram illustrating a lithium metal cutting system for a negative electrode according to another embodiment of the present invention.

[0028] Figure 3 : is a diagram illustrating a lithium metal cutting system for a negative electrode according to another embodiment of the present invention.

[0029] Figure 4 is a picture of a cut surface of lithium metal according to Comparative Example 1 of the present invention.

[0030] Figure 5 is a picture of a cut surface of lithium metal according to Comparative Example 2 of the present invention.

[0031] Figure 6 is a picture of a cut surface of lithium metal according to Example 1 of the present invention.

[0032] Figure 7 is a picture of a cut surface of lithium metal according to Example 2 of the present invention. DETAILED DESCRIPTION

[0033] The details of the embodiments of the present invention are provided in the following description. However, for the purpose of facilitating the understanding of the present invention, the following description should be understood as exemplary and should not be understood as limiting or defining the present invention. In addition, the present invention is not limited to the accompanying drawings. With reference to the following description and the accompanying drawings, those of ordinary skill in the art can implement the present invention in various forms within the scope of the technical concept of the present invention.

[0034] negative electrode

[0035] The negative electrode may include lithium metal. The negative electrode may be composed of pure lithium metal or a lithium alloy, or may be used by applying and drying a negative electrode active material on lithium metal.

[0036] 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 one 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 be a metal (Me) oxide of lithium (MeO x ) and one selected from the group consisting of Si, Sn, Zn, Mg, Cd, Ce, Ni, and Fe, such as Li x Fe2O3 (where 0 < 0 ≤ 1) or Li x WO2 (where 0 < x ≤ 1).

[0037] The lithium metal according to the present invention may have a protective layer, such as a lithium metal with a conventional electrolyte. The protective layer may include any material that is conductive to lithium ions, does not interfere with the operation of the battery, and does not react with lithium. Examples thereof include a garnet-type ceramic protective layer, a protective layer composed of lithium-substituted polyacrylic acid, and a molybdenum disulfide-based protective layer. Any protective layer may be used as long as it can improve the stability of the lithium metal.

[0038] The lithium metal is generally made to have a thickness of 3 μm to 500 μm. The lithium metal may also form micro-irregularities on the surface to strengthen the bonding with the negative electrode active material or the solid electrolyte, and may be used in various forms such as a film, sheet, foil, net, porous material, foam, non-woven material, etc.

[0039] The negative electrode active material includes, for example, carbon such as anthracite or graphitized carbon; Li x Fe2O3 (where 0 ≤ x ≤ 1), Li x WO2 (where 0 ≤ x ≤ 1) or Sn x Me 1-x Me' y O z (where Me is Mn, Fe, Pb, or Ge; Me' is Al, B, P, or Si, an element of Group 1, Group 2, or Group 3 of the periodic table, or a halogen; 0 < x ≤ 1; 1 ≤ y ≤ 3; and 1 ≤ z ≤ 8); 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, or Bi2O5; conductive polymers such as polyacetylene; and Li-Co-Ni-based materials.

[0040] Solid Electrolyte

[0041] The solid electrolyte particles may include at least one of sulfide-based solid electrolyte particles, oxide-based solid electrolyte particles and organic solid electrolyte particles. The solid electrolyte according to the present invention may use particles having a coated or modified surface. Sulfide-based solid electrolytes are superior to other solid electrolytes in terms of ionic conductivity and production cost. Therefore, the present invention provides the following embodiments using sulfide-based solid electrolytes.

[0042] Sulfide-based solid electrolytes have 10 -2 Up to 10 -3 S / cm, easy to form a contact interface between the electrode and the electrolyte, and the advantages of good mechanical strength and good mechanical flexibility. Sulfide-based solid electrolyte powder contains sulfur (S) and has the ionic conductivity of a metal in Group 1 or Group 2 of the periodic table, and may include Li-PS-based glass or Li-PS-based glass ceramics. The present invention is not specifically limited to sulfide-based solid electrolytes, and any sulfide-based material known for lithium battery applications may 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 and Li7P3S 11 .

[0043] The thickness of the solid electrolyte may be selected according to the desired characteristics of the battery. For example, when the electrolyte is densified by pressing, the thickness of the electrolyte may preferably be 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.

[0044] positive electrode

[0045] For example, the positive electrode may be manufactured by applying a positive electrode compound made by mixing a positive electrode active material composed of positive electrode active material particles, a conductive material, and a binder to a positive electrode collector, and a filler may be further added to the positive electrode compound as needed.

[0046] The positive electrode current collector is generally manufactured to have a thickness of about 3 μm to 500 μm, and is not particularly limited as long as it has high conductivity without causing any chemical changes in the battery, for example, selected from stainless steel, aluminum, nickel, titanium, and one of aluminum or stainless steel whose surface is treated with carbon, nickel titanium or silver, and specifically, aluminum can be used. The current collector may also have microscopic irregularities formed on its surface to increase the adhesion of the positive electrode active material, and may be in the form of a film, sheet, foil, net, porous material, foam, nonwoven material, etc.

[0047] In addition to the positive electrode active material particles, the positive electrode active material may include, but is not limited to, a layered compound such as lithium nickel oxide (LiNiO2) or a compound substituted with one or more transition metals; 1+x Mn 2-x O4 (wherein x is 0 to 0.33), such as LiMnO3, LiMn2O3 or LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxide such as LiV3O8, LiV3O4, V2O5 or Cu2V2O7; LiNi 1-x M x Ni-silicon type lithium nickel represented by O2 (wherein M is Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x is 0.01 to 0.3); represented by the formula LiMn 2-x M x Lithium manganese composite oxide represented by Li2Mn3MO8 (wherein M is Fe, Co, Ni, Cu or Zn) or LiMn2O4 (wherein a portion of Li is substituted by alkaline earth metal ions); disulfide compounds; and Fe2(MoO4)3.

[0048] The conductive material may be added generally in an amount of 0.1 wt% to 30 wt% based on the total weight of the mixture containing the positive electrode active material. The materials are not particularly limited as long as they are conductive and do not cause any chemical changes in the battery, for example, graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black or summer black; conductive fibers such as carbon fibers or metal fibers; metal powders such as carbon fluoride, aluminum or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive materials such as polyphenylene derivatives.

[0049] The binder included in the positive electrode is a component that helps the combination of the active material with the conductive material and with the current collector, and is typically added in an amount of 0.1wt% to 30wt% based on the total weight of the mixture containing the positive active material. Due to the addition of the binder, the combination of the positive electrode and the solid electrolyte can also be enhanced. The binder of the present invention is not particularly limited in this specification, and known methods can be used. The binder can be selected from the group consisting of polyamide-imide (PAI), polyimide (PI), polyamide (PA), polyamic acid, polyethylene oxide (PEO), polystyrene (PS), PEP-MNB (poly (ethylene-propylene-5-methylene-2-norbornene), VDF (polyvinylidene fluoride), PVDF-HFP (poly (vinylidene fluoride-co-hexafluoropropylene)), PS-NBR (polystyrene nitrile rubber), PMMANBR (poly (methacrylate) butadiene rubber) and combinations thereof. Any one or a mixture of two or more.

[0050] The surface of the positive electrode active material layer may be coated with a material such as LiNbO3 to form a buffer layer. The buffer layer may be formed of a material forming a buffer layer of 10 nm or less to suppress the interface resistance between the positive electrode and the solid electrolyte.

[0051] In order to facilitate understanding of the purpose of the present invention, the structure of the secondary battery is described exemplarily. The present invention relates to cutting lithium metal for negative electrode. Referring to the accompanying drawings, the lithium metal cutting system for negative electrode according to the present invention is described below.

[0052] Figure 1 : is a diagram illustrating a lithium metal cutting system for a negative electrode according to one embodiment of the present invention.

[0053] Reference Figure 1, the lithium metal cutting system may include a lithium metal supply unit, a lithium metal transport unit, and a lithium metal cutting unit. The lithium metal supply unit may include a lithium metal 100 and a winding roller 110 wound with the lithium metal 100. The lithium metal transport unit may include a first roller 200a, a second roller 200b, and a third roller 200c. The first refrigerant pipe 300a may be formed in the first roller 200a, the second refrigerant pipe 300b may be formed in the second roller 200b, and the third refrigerant pipe 300c may be formed in the third roller 200c. The lithium metal cutting unit may include a cutting member 400 and a cutting table 500. The cutting refrigerant pipe 510 may be formed in the cutting table 500.

[0054] The lithium metal supply unit can be configured to supply lithium metal to the lithium metal cutting unit so that the winding roller 110 can unwind the lithium metal in the form of a continuous uncut film. A refrigerant tube (not shown in the figure) through which the refrigerant flows can be arranged in the winding roller 110. By doing so, the lithium metal wound on the winding roller 110 can be cooled to prevent the lithium metal from adhering to the lithium metal conveying unit or the lithium metal cutting unit due to its low tensile strength during the lithium metal conveying process. In other words, the refrigerant flowing in the refrigerant tube (not shown in the figure) in the winding roller 110 can cool the lithium metal to increase the tensile strength of the lithium metal.

[0055] The type of refrigerant is not limited. For example, the refrigerant may include coolant, liquid nitrogen, and liquid helium. However, this is exemplary, and various substances may be used as refrigerants without limitation, as long as the purpose of cooling lithium metal to increase the tensile strength of lithium metal can be achieved.

[0056] The lithium metal transporting unit can transport the lithium metal provided from the lithium metal supplying unit. The lithium metal transporting unit can transport the lithium metal to the lithium metal cutting unit. Thus, the lithium metal in the form of a continuous film can be transported to the lithium metal cutting unit and cut.

[0057] In addition, the lithium metal transport unit can cool the lithium metal while transporting the lithium metal. The first refrigerant pipe 300a, the second refrigerant pipe 300b, and the third refrigerant pipe 300c may each include a refrigerant. The first refrigerant pipe 300a, the second refrigerant pipe 300b, and the third refrigerant pipe 300c may be provided with a refrigerant through a channel connected to the outside. Each refrigerant may include the above-mentioned coolant, liquid nitrogen, and liquid helium. In addition, as described above, various substances can be used as refrigerants as long as the purpose of increasing the tensile strength of the lithium metal by cooling the lithium metal can be achieved.

[0058] The first refrigerant pipe 300a, the second refrigerant pipe 300b and the third refrigerant pipe 300c may each have a refrigerant having different temperatures passing therethrough. For example, the temperature of the refrigerant may be reduced as it moves toward the first refrigerant pipe 300a, the second refrigerant pipe 300b and the third refrigerant pipe 300c. Although the temperature in the first refrigerant pipe to the third refrigerant pipe 300a, 300b, 300c may be gradually reduced, the temperature in the second refrigerant pipe 300a and the third refrigerant pipe 300b may each be lower than the temperature in the first refrigerant pipe 300a and be equal to each other. In addition, the temperature in the first refrigerant pipe to the third refrigerant pipe 300a, 300b, 300c may be set without restriction, as long as they can cool the lithium metal to improve its tensile strength.

[0059] The first to third rollers 200a, 200b, 200c may be arranged at different heights. Therefore, the lithium metal in the form of a film may be conveyed in a bent state according to the positions of the first to third rollers 200a, 200b, 200c. Since lithium metal has low tensile strength, it is necessary to sufficiently cool it before reaching the lithium metal cutting section, and in the lithium metal cutting system according to the present invention, since more surface areas are exposed to the lithium metal conveying section as the first to third rollers 200a, 200b, 200c are arranged at different heights, the lithium metal may be relatively more cooled by the first to third rollers 200a, 200b, 200c.

[0060] However, in an embodiment, the temperatures of the refrigerants supplied to the first to third refrigerant pipes 300a, 300b, 300c may be the same as each other.

[0061] The lithium metal cutting section can cut the lithium metal transported in the form of a film. The lithium metal can be located on the cutting table 500. In this process, a cutting refrigerant tube 510 is formed in the cutting table 500, and the refrigerant can flow in the cutting refrigerant tube 510. The cutting refrigerant tube 510 can be provided with a refrigerant through a channel connected to the outside. The refrigerant may include a coolant, liquid nitrogen, and liquid helium as described above. In addition, as described above, various substances can be used as refrigerants as long as the purpose of cooling the lithium metal to improve the tensile strength of the lithium metal can be achieved. Due to the cutting refrigerant tube 510, the lithium metal can be cooled again on the cutting table 500. Therefore, the lithium metal can have an improved tensile strength on the cutting table 500. That is, the lithium metal can be neatly cut by the cutting member 400. Here, the definition of "neatly cutting" refers to cutting the lithium metal without adhering to the cutting member. The temperature of the refrigerant flowing through the cutting refrigerant tube 510 can be less than or equal to the temperature of the refrigerant flowing through the refrigerant tube of the adjacent roller.

[0062] As the cutting member 400 , various materials can be used as long as they can cut lithium metal. For example, a cutter or a punch or the like can be used as the cutting member 400 .

[0063] However, in an embodiment, the lithium metal cutting part may not be provided with a refrigerant. If the lithium metal is sufficiently cooled in the lithium metal supply part to ensure the tensile strength of the lithium metal, the lithium metal delivered to the lithium metal cutting part may be directly cut without further cooling.

[0064] Figure 2 is a diagram illustrating a lithium metal cutting system for a negative electrode according to another embodiment of the present invention. In addition to using five rollers, Figure 2 Can be used with Figure 1 Therefore, the description of the redundant structure is omitted here.

[0065] Reference Figure 2 , the lithium metal cutting system may include a lithium metal supply unit, a lithium metal transport unit, and a lithium metal cutting unit. The lithium metal supply unit may include a lithium metal 100 and a winding roller 110 wound with the lithium metal 100. The lithium metal transport unit may include a first roller 200a, a second roller 200b, a third roller 200c, a fourth roller 200d, and a fifth roller 200e. The first refrigerant tube 300a may be formed in the first roller 200a, the second refrigerant tube 300b may be formed in the second roller 200b, the third refrigerant tube 300c may be formed in the third roller 200c, the fourth refrigerant tube 300d may be formed in the fourth roller 200d, and the fifth refrigerant tube 300e may be formed in the fifth roller 200e. The lithium metal cutting unit may include a cutting member 400 and a cutting table 500. In the cutting table 500, a cutting refrigerant tube 510 may be formed.

[0066] In the winding roller 110, a refrigerant pipe (not shown in the figure) through which the refrigerant flows may be arranged. By doing so, the lithium metal wound on the winding roller 110 can be cooled to prevent the lithium metal from adhering together at the lithium metal supply part due to its low tensile strength during the lithium metal conveying process, or to prevent the lithium metal from adhering to the lithium metal conveying part or the lithium metal cutting part. In other words, the refrigerant flowing through the refrigerant pipe (not shown in the figure) in the winding roller 110 can cool the lithium metal to improve the tensile strength of the lithium metal.

[0067] The lithium metal transport section can be used to cool the lithium metal while transporting the lithium metal. Each of the first to fifth refrigerant tubes 300a, 300b, 300c, 300d, and 300e can include a refrigerant. Each of the first to fifth refrigerant tubes 300a, 300b, 300c, 300d, and 300e can be provided with a refrigerant through a channel connected to the outside. Each refrigerant may include the above-mentioned coolant, liquid nitrogen, and liquid helium. In addition, as described above, various substances can be used as refrigerants as long as the purpose of cooling the lithium metal to improve the tensile strength of the lithium metal can be achieved.

[0068] Each of the first to fifth refrigerant tubes 300a, 300b, 300c, 300d, 300e can have a different temperature of the refrigerant flowing therethrough. For example, the temperature of the refrigerant can be reduced from the first refrigerant tube 300a to the fifth refrigerant tube 300e. The temperature of the first to fifth refrigerant tubes 300a, 300b, 300c, 300d, 300e can be sequentially and gradually reduced, but at least some of the refrigerant tubes can have the same temperature. In addition, the temperature of the first to fifth refrigerant tubes 300a, 300b, 300c, 300d, 300e can be set without restriction, as long as they can cool the lithium metal to improve its tensile strength.

[0069] The first to fifth rollers 200a, 200b, 200c, 200d, 200e can be set at different heights. Therefore, the lithium metal in the form of a film can be conveyed in a bent state according to the position of the first to fifth rollers 200a, 200b, 200c, 200d, 200e. Since lithium metal has low tensile strength, it is necessary to fully cool it before reaching the lithium metal cutting section, and in the lithium metal cutting system according to the present invention, since the first to fifth rollers 200a, 200b, 200c, 200d, 200e are set at different heights from each other, more surface areas are exposed to the lithium metal conveying section, so the lithium metal can be cooled relatively more by the first to fifth rollers 200a, 200b, 200c, 200d, 200e.

[0070] In addition, Figure 1 Compared with the embodiment of Figure 2 Embodiments may allow for more cooling of the lithium metal.

[0071] 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 as one another.

[0072] The lithium metal cutting section can cut the lithium metal transported in the form of a film. The lithium metal can be located on the cutting table 500. In this process, a cutting refrigerant tube 510 is formed in the cutting table 500, and a refrigerant can flow in the cutting refrigerant tube 510. The cutting refrigerant tube 510 can be provided with a refrigerant through a channel connected to the outside. Due to the cutting refrigerant tube 510, the lithium metal can be cooled again on the cutting table 500. Therefore, the lithium metal can have an improved tensile strength on the cutting table 500. That is, the lithium metal can be neatly cut by the cutting member 400. The definition of "neatly cutting" refers to cutting the lithium metal without adhering to the cutting member. The temperature of the refrigerant flowing through the cutting refrigerant tube 510 can be less than or equal to the temperature of the refrigerant flowing through the refrigerant tube of the adjacent roller.

[0073] As the cutting member 400 , various materials can be used as long as they can cut lithium metal. For example, a cutter, a punch, etc. can be used as the cutting member 400 .

[0074] Figure 3 is a diagram illustrating a lithium metal cutting system for a negative electrode according to another embodiment of the present invention. In addition to using the first to n-th rollers, Figure 3 Can be used with Figure 1 and Figure 2 Therefore, the description of the redundant structure is omitted here.

[0075] Reference Figure 3 , the lithium metal cutting system according to the present invention can be designed in various ways without limiting the number of rollers. The rollers can be used freely as long as they sufficiently cool the lithium metal. For example, the first to n-th rollers 200a, 200b, ..., 200n can be used to cool the lithium metal. The first to n-th rollers 200a, ..., 200n can each include a refrigerant pipe 300a, 300b, ..., 300n.

[0076] The temperature of the refrigerant flowing through the refrigerant tubes 300a, 300b, ..., 300n may gradually decrease. That is, the temperature of the refrigerant may decrease from the first refrigerant tube 300a to the nth refrigerant tube 300n.

[0077] For example, if the temperature of the refrigerant in the first refrigerant tube 300a is 10°C to -10°C, the nth refrigerant tube 300n may be set to -40°C to -50°C, where the temperature of the refrigerant decreases as it flows from the first refrigerant tube 300a to the nth refrigerant tube 300n.

[0078] The lithium metal 100 is preferably cooled to a temperature of about -10°C to -30°C before final cutting. Therefore, as the lithium metal 100 at room temperature is conveyed by the rollers, its temperature is preferably gradually reduced so that when it reaches the cutting table 500, it is at a temperature of -10°C to -30°C. The temperature reduction of the lithium metal 100 may be reduced to a certain percentage (e.g., a specific percentage), or may be reduced to a certain range, and may be applied in any manner so that the temperature of the lithium metal 100 is in a temperature range of -10°C to -30°C when it reaches the cutting table 500.

[0079] If the refrigerant flows only in the cutting table 500, the cooling time of the lithium metal 100 is too short to sufficiently cool the lithium metal 100. Therefore, the cut surface cannot be smoothly formed when the lithium metal 100 is repeatedly cut. If the lithium metal 100 is conveyed to the cutting table 500 while being cooled by rollers, the temperature of the lithium metal 100 can be reduced to a desired temperature so that the cut surface can be smoothly formed.

[0080] As described above, embodiments of the present invention are provided. However, for ease of understanding the purpose of the present invention, these descriptions should be understood as exemplary and should not be understood as limiting the present invention. Those skilled in the art can refer to this specification and the accompanying drawings, and within the scope of the technical concept of the present invention, make appropriate modifications to the embodiments of the present invention and the working examples, including omitting, changing, replacing or adding other structures to all or part of the embodiments of the present invention and the working examples. Therefore, the scope of protection sought by the present invention should be interpreted according to the attached claims, and all its technical concepts should be interpreted as being included in the scope of the claims.

[0081] Unless otherwise defined, all terms and expressions used in this specification are understood by those of ordinary skill in the art. In addition, the terms and expressions used in this specification should be interpreted broadly and should not be interpreted as limiting.

[0082] In the present specification, the expression "comprising" does not exclude the existence or addition of one or more other components in addition to the above-mentioned components.

[0083] Furthermore, as used herein, expressions in the singular are intended to include the plural form unless the context clearly excludes the plural form.

[0084] Embodiments of the present invention

[0085] Hereinafter, examples are provided to facilitate understanding of the present invention. The following examples are provided to illustrate the present invention, but the present invention is not limited thereto.

[0086] Example

[0087] Example 1

[0088] Reference Figure 1 , after preparing a lithium metal supply section including a lithium metal 100 and a winding roller 110 wound with the lithium metal 100, a lithium metal sheet is placed in a lithium metal conveying section including a first roller 200a, a second roller 200b, and a third roller 200c. A first refrigerant tube 300a is formed in the first roller 200a, a second refrigerant tube 300b is formed in the second roller 200b, and a third refrigerant tube 300c is disposed in the third roller 200c. The refrigerant temperature of the first refrigerant tube 300a is set to -20°C, the refrigerant temperature of the second refrigerant tube 300b is set to -30°C, and the refrigerant temperature of the third refrigerant tube 300c is set to -40°C. Then, the metal lithium sheet is conveyed to the lithium metal conveying section at a speed of 1 cm / s. The lithium metal sheet cooled to 20°C is then cut with a cutter.

[0089] Example 2

[0090] The lithium metal sheet was cut in the same manner as in Example 1, except that the refrigerant temperatures of the first refrigerant tube 300a and the third refrigerant tube 300c were both set to -30°C.

[0091] Comparative Example 1

[0092] Using the lithium metal transporting part without the refrigerant pipe, the lithium metal sheet was cut in the same manner as in Example 1 except that the cooling process was not performed.

[0093] Comparative Example 2

[0094] The lithium metal sheet was cut in the same manner as in Example 1, except that the lithium metal sheet was cooled by conventional liquid nitrogen cooling instead of the refrigerant tube by immersing the lithium metal sheet in liquid nitrogen for 10 seconds.

[0095] Experimental Example 1: Evaluation of Lithium Metal Sheet Cross Section

[0096] exist Figures 4 to 7 The cross sections of the lithium metal sheets manufactured in the working examples and the comparative examples are photographed in FIG. The upper part of each figure shows a picture of the top of the cut surface taken with an optical microscope, and the lower part shows the illumination of the cross section of the lithium metal sheet taken with a laser optical illuminometer.

[0097] Figure 4 is a cross section of the lithium metal sheet manufactured in Comparative Example 1 without undergoing a cooling process, showing that the cut surface is not smooth.

[0098] Figure 5 is a cross section of a lithium metal sheet prepared in Comparative Example 2 and cooled by immersion in liquid nitrogen, showing a smooth cut surface.

[0099] Figure 6is a cross section of the lithium metal sheet manufactured in Example 1, which was cooled by setting the temperature of the refrigerant pipe to gradually decrease, and it can be seen that the cut surface is smoother than that of the conventional liquid nitrogen cooling method.

[0100] Figure 7 is a cross section of the lithium metal sheet manufactured in Example 2, which has been cooled to the same temperature as the refrigerant pipe, and it can be seen that the cut surface is slightly less smooth than that in Example 1.

[0101] Each of the exemplary embodiments described herein may be combined with one another, and unless contradictory, content described in a specific embodiment may also apply to other embodiments even if not described in the other embodiments.

[0102] [reference numerals]

[0103] 100: Lithium metal

[0104] 110: Winding roller

[0105] 200a, 200b, 200c, 200d, 200e: first to fifth rollers

[0106] 300a, 300b, 300c, 300d, 300e: first refrigerant pipe to fifth refrigerant pipe

[0107] 400: Cutting components

[0108] 500: Cutting table

[0109] 510: Cutting refrigerant pipes

Claims

1. A lithium metal cutting system for a negative electrode, the lithium metal cutting system for a negative electrode comprising: A lithium metal supply unit for providing lithium metal; a lithium metal transporting unit configured to transport the lithium metal provided from the lithium metal supplying unit; as well as a lithium metal cutting section, the lithium metal cutting section being used to cut the lithium metal transported by the lithium metal transport section, The lithium metal transport unit includes a plurality of rollers and a refrigerant pipe disposed in each of the plurality of rollers.

2. The negative electrode lithium metal cutting system according to claim 1, characterized in that: The refrigerant tube of each of the plurality of rollers is provided with a refrigerant, and The temperature of the refrigerant decreases from the lithium metal supply unit to the lithium metal transport unit.

3. The negative electrode lithium metal cutting system according to claim 2, characterized in that: The temperature of the refrigerant gradually decreases.

4. The negative electrode lithium metal cutting system according to claim 2, characterized in that: The lithium metal cutting unit comprises: Cutting table, and A cut refrigerant tube is disposed in the lithium metal cutting table.

5. The negative electrode lithium metal cutting system according to claim 4, characterized in that: The cut refrigerant tube is also provided with refrigerant, and The temperature of the refrigerant supplied to the cut refrigerant tube is lower than or equal to the temperature of the refrigerant supplied to the adjacent refrigerant tube.

6. The negative electrode lithium metal cutting system according to claim 1, characterized in that: At least some of the plurality of rollers are disposed at different heights.

7. The negative electrode lithium metal cutting system according to claim 1, characterized in that: The lithium metal supply unit includes a winding roller for winding the lithium metal, and A refrigerant is provided into the winding roller.

8. The negative electrode lithium metal cutting system according to claim 1, characterized in that: The refrigerant tube of each of the plurality of rollers is provided with a refrigerant, and The refrigerants have the same temperature as each other.

9. The negative electrode lithium metal cutting system according to claim 8, characterized in that: The refrigerant is provided into the cut refrigerant tube, and The temperature of the refrigerant supplied to the cut refrigerant tube is lower than or equal to the temperature of the refrigerant supplied to the adjacent refrigerant tube.

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