Method for manufacturing unit lithium electrode and method for manufacturing electrode stack

Abstract

The present disclosure relates to a method for manufacturing a unit lithium electrode, comprising: after cutting a sheet-shaped lithium metal electrode into the size of the unit lithium electrode, removing a protective film through an adhesive film in which an adhesive layer is formed on one surface of a substrate film, wherein the sheet-like lithium metal electrode comprises a current collector, a lithium metal layer formed on one or both surfaces of the current collector, and a protective film attached to the surface of the lithium metal layer; the invention also relates to a manufacturing method of an electrode stack comprising the unit lithium electrode.

Description

Technical Field

[0001] Cross-references to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2022-0178485 filed on December 19, 2022, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

[0003] The present disclosure relates to a method for manufacturing a unit lithium electrode and a method for manufacturing an electrode stack including the unit lithium electrode. Background Art

[0004] As the technology development and demand for mobile devices grow, the demand for secondary batteries as energy sources is rapidly increasing. Among such secondary batteries, lithium secondary batteries with high energy density and operating potential, long cycle life and low self-discharge rate have been commercialized and widely used.

[0005] Representatively, in terms of battery shape, there is a very high demand for square secondary batteries or pouch-shaped secondary batteries that are thin enough to be applied to products such as mobile phones, and in terms of battery materials, there is a very high demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries that exhibit high energy density, discharge voltage and output stability.

[0006] Generally, a lithium secondary battery has a structure in which an electrode assembly consisting of a positive electrode, a negative electrode and a porous separator is impregnated with a non-aqueous electrolyte. In addition, the positive electrode is generally manufactured by coating a positive electrode mixture containing a positive electrode active material on an aluminum foil, and the negative electrode is manufactured by coating a negative electrode mixture containing a negative electrode active material on a copper foil.

[0007] Typically, the positive electrode active material is a lithium transition metal oxide, and the negative electrode active material is a carbon-based material.

[0008] However, recently, lithium metal batteries using lithium metal itself, which exhibits high energy density, as a negative electrode active material have been commercialized.

[0009] At this time, lithium metal used as the negative electrode is the most popular material as the negative electrode material for high energy density batteries because of its low density (0.54 g / cm 3 ) and a very low standard reduction potential (-3.045 V SHE). In addition, although they have problems due to their high chemical activity, with the continued increase and rapid development of the use of mobile communications and portable electronic devices in recent years, the demand for the development of high energy density secondary batteries continues to increase. Therefore, the demand for the use of lithium metal anodes continues to increase.

[0010] At this time, when a lithium metal electrode is used as a negative electrode, lithium metal has high reactivity, and it reacts with moisture in the air to produce byproducts such as LiOH, Li2O, Li2CO3, and Li3N. This may significantly deteriorate the performance of the manufactured battery and even cause an internal short circuit. In addition, lithium is a metal with very low strength, which is a problem that it is difficult to use it as a metal immediately.

[0011] Therefore, when lithium metal is used as the negative electrode active material, a polymer carrier film such as a PET film is usually attached to the lithium metal electrode as a protective film for transportation. However, since the protective film must be removed before assembling the electrode assembly, it is best to remove the protective film as late as possible. However, when cutting is performed together with the protective film to manufacture a unit electrode, the lithium metal and the protective film adhere together to the cut surface due to the cutting pressure. When the protective film is removed before cutting, the reactivity problem of lithium metal still exists.

[0012] Therefore, it is necessary to develop a technology that can solve such problems and provide a unit lithium electrode with excellent quality that can be used in a lithium metal battery. Summary of the invention

[0013] Technical issues

[0014] An object of the present disclosure is to provide a method for manufacturing a unit lithium electrode capable of effectively removing a protective film from a lithium electrode after cutting into the size of the unit lithium electrode.

[0015] Another object of the present disclosure is to provide a method of manufacturing an electrode stack using the unit lithium electrode after manufacturing the unit lithium electrode.

[0016] Technical Solution

[0017] According to one embodiment of the present disclosure, a method for manufacturing a unit lithium electrode is provided, comprising: after cutting a sheet-like lithium metal electrode into the size of the unit lithium electrode, removing a protective film through an adhesive film having an adhesive layer formed on one side of a substrate film, wherein the sheet-like lithium metal electrode comprises a current collector, a lithium metal layer formed on one side or both sides of the current collector, and a protective film attached to the surface of the lithium metal layer.

[0018] The protective film may be one selected from the group consisting of a polymer film, a polymer electrolyte membrane, a release film, a vapor deposition film, a metal foil, a glass fiber cloth and a functional multilayer film.

[0019] In addition, the method for manufacturing the unit lithium electrode may further include a tab-forming cutting step of forming a tab before, after, or simultaneously with cutting the sheet-like lithium metal electrode into the size of the unit lithium electrode.

[0020] On the other hand, the step of removing the protective film can be performed by bringing the adhesive layer of the adhesive film into contact with the surface of the protective film and then peeling it off. In this case, the adhesive layer of the adhesive film to be removed can be formed on the entire side of the substrate film, or can be formed in a pattern shape such as a line or a dot.

[0021] In addition, the method of manufacturing the unit lithium electrode may further include pressing the unit lithium electrode after removing the protective film.

[0022] The pressing may be performed by a pair of pressing rollers.

[0023] According to another embodiment of the present disclosure, there is provided a method for manufacturing an electrode stack for a lithium metal battery, including preparing a unit lithium electrode using the method for manufacturing a unit lithium electrode, and stacking the unit lithium electrode with a separator, or with a positive electrode and a separator.

[0024] At this time, the electrode stack can be a bi-cell in which the electrodes at both ends have the same polarity, a full cell in which the electrodes at both ends have different polarities, a single cell in which the separator and the unit lithium electrode are stacked, or a stacked electrode assembly in which two or more positive electrodes are alternately arranged with the unit lithium electrode with a separator interposed therebetween.

[0025] Beneficial Effects

[0026] The manufacturing method of the unit lithium electrode according to the contents of the present disclosure removes the protective film after cutting into unit lithium electrodes. The method simply removes the protective film by using an adhesive film having an adhesive layer formed on one side, thereby being able to minimize the impact on the lithium metal layer caused by the removal of the protective film while maintaining the protective film for as long as possible, which has the effect of preventing contamination due to the high reactivity of lithium metal. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of a method for manufacturing a unit lithium electrode and an electrode stack according to one embodiment of the present disclosure.

[0028] Figure 2 is a cross-sectional view of a sheet-shaped lithium metal electrode according to one embodiment of the present disclosure.

[0029] Figure 3 and Figure 4 is a schematic diagram of an adhesive film for removing a protective film according to one embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] The terms and words used in this specification and claims should not be interpreted as limited to the usual meaning or dictionary definition, but should be interpreted as having meanings and concepts related to the technical scope of the present disclosure based on the rule that the inventor can appropriately define the terms and words as the terms that most appropriately describe the best method of implementing the present invention known to him. Therefore, the embodiments described herein and the configurations shown in the drawings are only the most preferred embodiments of the present disclosure and do not represent the entire gist of the present disclosure, so it should be understood that various equivalents and modifications that can replace the embodiments and configurations may exist at the time of filing this application, and the scope of the present invention is not limited to the embodiments described below.

[0031] The present disclosure will be described in detail below with reference to the accompanying drawings and exemplary embodiments. The terms or words used in this specification and the appended claims should not be considered to be limited to the ordinary meaning or dictionary meaning, but should be interpreted in a meaning and concept consistent with the technical concept of the present disclosure based on the principle that inventors can appropriately define the concept of the terms in order to appropriately explain their own inventions in the best way.

[0032] In addition, the embodiments described herein and the configurations shown in the accompanying drawings are merely the most preferred embodiments of the present disclosure and do not represent the entire subject matter of the present disclosure. Therefore, it should be understood that various equivalents and modifications that can replace the embodiments and configurations may exist when this application is submitted.

[0033] According to one embodiment of the present disclosure, a method for manufacturing a unit lithium electrode is provided, comprising: after cutting a sheet-like lithium metal electrode into the size of the unit lithium electrode, removing a protective film through an adhesive film having an adhesive layer formed on one side of a substrate film, wherein the sheet-like lithium metal electrode comprises a current collector, a lithium metal layer formed on one side or both sides of the current collector, and a protective film attached to the surface of the lithium metal layer.

[0034] Next, for easy understanding, the method of manufacturing the unit lithium electrode will be described with reference to the accompanying drawings.

[0035] Figure 1 is a schematic diagram of a method for manufacturing a unit lithium electrode and an electrode stack according to one embodiment of the present disclosure, Figure 2 is a cross-sectional view of a sheet-like lithium metal electrode according to one embodiment of the present disclosure, Figure 3 and Figure 4 is a schematic diagram of an adhesive film for removing a protective film according to one embodiment of the present disclosure.

[0036] Referring to these drawings, first, in order to manufacture a unit lithium electrode, a sheet-shaped lithium metal electrode 110 is provided.

[0037] As explained above, since lithium metal is very soft and highly reactive, it is usually introduced into the process in a state where a protective film is attached to the lithium metal layer, rather than in a state where the surface of the lithium metal layer is exposed.

[0038] Specifically, the sheet-shaped lithium metal electrode 110 includes a current collector 111 , a lithium metal layer 112 formed on both surfaces of the current collector 111 , and a protective film 113 attached to the surface of the lithium metal layer 112 .

[0039] Here, the current collector 111 is not limited to the current collector conventionally used for the negative electrode, and can be used in various ways. For example, various metals or alloys such as copper, silver or nickel can be used. The current collector 111 plays a role in enhancing the strength of the lithium metal layer (which is a lithium ion source) provided in the lithium battery and improving the processing characteristics.

[0040] The lithium metal layer 112 may be attached to the current collector 111 using an adhesive material, or may be attached by pressing with a plate press, or lithium metal may be deposited, or may be formed on the current collector 111 by a transfer method from another substrate. That is, the method of forming the lithium metal layer 112 on the current collector 111 is not limited as long as the lithium metal layer 112 is in a form attached to the current collector 111.

[0041] The lithium metal layer 112 is used to provide lithium ions, and may be formed to have a thickness of 0.1 μm to 30 μm, specifically 1 μm to 30 μm, and more specifically 5 μm to 20 μm.

[0042] If the thickness is outside the above range and is too thin, it is difficult to supply sufficient lithium ions, whereas if the thickness is too thick, the capacity relative to the volume becomes small, which is not preferable.

[0043] The protective film 113 is used to protect lithium metal from moisture in the air. Here, the protective film 113 can be formed of a polymer film, a polymer electrolyte membrane, a release film, a vapor deposition film, a metal foil, a glass fiber cloth, a functional multilayer film, and the like.

[0044] Here, the polymer film is processed by treating the surface of a film made of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyester, polyethylene (PE), polypropylene (PP), polyolefin, polyamide, etc. by coating or vapor deposition, and various functions can be imparted as needed.

[0045] As the polymer electrolyte membrane, PEO, polysiloxane, PDMS, PMMA, PAN-based polymer, acrylate-based polymer, etc. can be used. The surface of the protective film 113 can be given moisture permeability, and the moisture permeability of the protective film 113 can be set to 0 to 10 g / m 2 / sky.

[0046] The vapor deposition film allows metal to be deposited on the film to block moisture. Films such as polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET) and nylon are mainly used. Metal foils such as aluminum foil or copper foil can be used as the protective film 113.

[0047] The glass fiber has high strength and can be used in the protective film 113 to increase the strength of the film. It can also be used by coating polymers such as PVDF, PVDF-HFP, PE, and PP onto glass fiber cloth.

[0048] The functional multilayer film is processed by stacking or coating various resins on a base film, and has various functions according to the selected resins.

[0049] As the protective film 113, in addition to such functional films, a film made of a general plastic film such as polypropylene, polyethylene, PET, nylon, polyester, polyolefin, and polyamide may be used.

[0050] Alternatively, the protective film 113 may contain a resin that blocks or absorbs moisture.

[0051] The protective film 113 may be formed by attaching the above-mentioned film form to the lithium metal layer 112. In this case, an adhesive material may be applied to the surface of the protective film 113 facing the lithium metal layer 112, or an adhesive material may be applied to the lithium metal layer 112 and the protective film 113 may be attached, or the film 113 itself may be made of a polymer material having adhesive properties.

[0052] Alternatively, it may be formed by applying a protective film composition solution onto the lithium metal layer 112 and then drying it.

[0053] Here, the thickness of the protective film 113 may be 10 nanometers to 10 micrometers. If the thickness is less than this range, it may not provide sufficient protection from atmospheric moisture, and if the thickness is too thick, it is not economical, so the thickness may be appropriately selected to a degree capable of protecting the lithium metal layer 112.

[0054] In addition, the area of ​​the protective film 113 may be equal to or greater than the area of ​​the lithium metal layer 112. If the area is smaller than the area of ​​the lithium metal layer 112, the lithium metal layer 112 may not be effectively protected. On the other hand, if the area of ​​the protective film 113 is larger than the area of ​​the lithium metal layer 112, it may cover the side of the lithium metal layer 112, which is more preferred.

[0055] According to the present disclosure, before removing the protective film 113 , the sheet-shaped lithium metal electrode 110 is cut into the size of the unit lithium electrode.

[0056] In addition, before, after or simultaneously with cutting into the size of the unit lithium electrode, a cutting step for forming a tab is performed to form the tab.

[0057] Here, both the step of cutting the sheet-shaped lithium metal electrode 110 into the size of the unit lithium electrode and the cutting step for forming the tab are performed by the cutters 141 and 142 .

[0058] On the other hand, as in the present disclosure, when the current collector 111, the lithium metal layer 112 and the protective film 113 are all cut at the same time, the cutting pressure causes the current collector 111, the lithium metal film 112 and the protective film 113 to be pressed in the cutting direction and adhere to the cut surface.

[0059] However, in this form, a method of effectively removing only the protective film 113 is unknown.

[0060] Therefore, the inventors of the present application devised a method capable of efficiently removing only the protective film 113 in a very simple manner after cutting into the size of the unit lithium electrode.

[0061] Specifically, the protective film 113 is removed through the adhesive film 130 in which the adhesive layer 132 is formed on one surface of the base material film 131 .

[0062] Specifically, Figure 1 As shown, the removal is performed by the following method, wherein the position of the adhesive film 130 is set so that the adhesive layer 132 of the adhesive film 130 can contact the surface of the protective film 113, and then the adhesive layer 132 is brought into contact with the surface of the protective film 113, the protective film 113 is attached to the adhesive film 130 by the adhesive force, and then the protective film 113 is peeled off from the lithium metal layer 112 by moving the adhesive film 130 away from the lithium metal unit.

[0063] In the case of this method, the protective film 113 can be removed in a very simple manner using the adhesive film 130 , which can minimize the influence on the surface of the lithium metal layer 112 .

[0064] Meanwhile, the sheet-like lithium metal electrode 110 is cut into the unit lithium electrodes 120 and then the protective film 113 is removed just before being stacked with a positive electrode and a separator, thereby minimizing external exposure of the lithium metal layer 112 and effectively preventing it from being contaminated.

[0065] Here, the adhesive layer 132 of the adhesive film 130 may be Figure 1 As shown in FIG. 1 , the substrate film 131 may be formed on the entire surface thereof, or may be formed on the entire surface of the substrate film 131 as shown in FIG. Figure 3 As shown in FIG. 1 , the substrate film 131 ′ may be formed in a dot pattern on one side thereof, or may be formed in a dot pattern as shown in FIG. Figure 4 As shown, the substrate film 131 ″ is formed in a linear pattern on one surface thereof.

[0066] That is, the adhesive layer 132 is not limited as long as it can effectively remove the protective film 113 using adhesive force, and may be formed in various shapes.

[0067] In addition, the shape of the adhesive film 132 is not limited, however, in order to remove only the protective film 113 from the lithium metal layer 112 without affecting other components, the film may be bent into a shape (i.e., a U-shape) with both ends bent in the opposite direction to the protective film 113, and used in the step of removing the protective film 113. In this case, the adhesive force is formed by line contact or surface contact with the protective film 113.

[0068] In order to remove the protective film 113 using the adhesive film 130 in this manner, the adhesive force between the adhesive film 130 and the protective film 113 must be greater than the adhesive force between the protective film 113 and the lithium metal layer 112 .

[0069] Therefore, the formation area of ​​the adhesive layer 132 on one side of the base film 131 is determined within a range that satisfies the adhesive force. For example, the adhesive layer 132 may be formed to have an area of ​​30% to 100% of the total area of ​​the base film 131 .

[0070] If the area is outside the above range or is too low, sufficient adhesion strength cannot be obtained.

[0071] In addition, the substrate film 131 constituting the adhesive film 130 used herein may be a material similar to the protective film 113, specifically, a polymer film. For example, the substrate film may be made of PVDF, PVDF-HFP, polyester, polyethylene (PE), polypropylene (PP), polyolefin or polyamide material.

[0072] As the adhesive layer 132, for example, polydopamine, olefin adhesive, polysiloxane adhesive, acrylic adhesive, rubber adhesive, epoxy adhesive, etc. can be used. Specifically, an acrylic adhesive having excellent adhesive strength can be used.

[0073] As described above, the unit lithium electrode 120 from which the protection film 113 is removed makes the surface of the lithium metal layer 112 smooth, and at the same time, a step of pressing the unit lithium electrode 120 may be performed to maintain a cell as a whole.

[0074] Here, the pressing may be performed using a pair of rollers 150. At this time, considering the soft properties of the lithium metal layer 112, the pressure may be appropriately selected within a range that makes the surface of the lithium metal layer 112 smooth and does not damage it. For example, the pressing may be performed within a range of 0.1 kgf / mm to 50 kgf / mm.

[0075] The unit lithium electrode 120 manufactured in this manner may be stacked with a separator 220 and a positive electrode 210 immediately after removing the protective film 113 , thereby manufacturing an electrode stack 200 .

[0076] Figure 1 An electrode stack 200 is shown in which the positive electrode 210 and the unit lithium electrode 120 are stacked with a separator 220 interposed therebetween, however, the electrode stack is not limited to this structure and may be manufactured in various forms.

[0077] For example, the electrode stack can be a bicell in which the electrodes at both ends have the same polarity, a full cell in which the electrodes at both ends have different polarities, a single cell in which a separator and a unit lithium electrode are stacked, or a stacked electrode assembly in which two or more positive electrodes are alternately arranged with the unit lithium electrodes with a separator interposed therebetween.

[0078] Specifically, the bi-battery may have a structure in which a positive electrode / separator / unit lithium electrode / separator / positive electrode or a unit lithium electrode / separator / positive electrode / separator / unit lithium electrode is stacked, and the full battery may be as follows: Figure 1 The illustrated example has a structure in which a positive electrode / separator / unit lithium electrode are stacked, and the single cell may have a structure in which one or two lithium electrodes and a separator are stacked.

[0079] After stacking bicells, full cells or single cells in this manner, they are arranged on a separation membrane and wound in one direction to form a stacked-folded electrode assembly, or wound in a zigzag shape to form a zigzag electrode assembly, or stacked and layered with a separator interposed therebetween to form a stacked-laminated electrode assembly.

[0080] Alternatively, as described above, it may mean a stacked electrode assembly in which two or more, namely, a plurality of unit lithium electrodes and a plurality of positive electrodes are alternately arranged at once with a separator interposed therebetween.

[0081] Here, the positive electrode is manufactured by applying a positive electrode slurry containing a positive electrode active material, a conductive material, and a binder onto a positive electrode collector, drying it, and rolling it.

[0082] The positive electrode current collector is not particularly limited as long as it has conductivity and does not cause chemical changes in the battery, and can use, for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel whose surface is treated with carbon, nickel, titanium, silver, etc. In addition, the thickness of the positive electrode current collector can be 3 μm to 500 μm, and fine concavoconvexity can be formed on the surface of the current collector to increase the adhesion strength of the positive electrode active material. For example, it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams, and non-woven fabrics.

[0083] The positive electrode active material may include a layered compound, such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted by one or more transition metals; lithium manganese oxide, such as Li 1+x Mn 2-x O4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides, such as LiV3O8, LiV3O4, V2O5 and Cu2V2O7; 1-x M x Ni-site lithium nickel oxide represented by O2 (wherein M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3); 2-x M x Lithium manganese composite oxide represented by Li2Mn3MO8 (wherein M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1); Lithium manganese composite oxide represented by LiNi x Mn 2-xO4 represents a lithium manganese composite oxide having a spinel structure; LiMn2O4 in which a portion of Li in the chemical formula is replaced by an alkaline earth metal ion; a disulfide compound; Fe2(MoO4)3, etc., but are not limited thereto.

[0084] The conductive material is used to impart conductivity to the electrode, and the conductive material can be used without particular limitation as long as it has electronic conductivity and does not cause chemical changes in the battery to be configured. Specific examples thereof include carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, and carbon fiber; graphite, such as natural graphite and artificial graphite; metal powder or metal fiber, such as copper, nickel, aluminum, and silver; conductive whiskers, such as zinc oxide and potassium titanate; conductive metal oxides, such as titanium oxide; or conductive polymers, such as polyphenylene derivatives, and any one of them can be used alone or as a mixture of two or more of them. Based on the total weight of the positive electrode material, the content of the conductive material can be 1% to 30% by weight, specifically 1% to 10% by weight, and more specifically 1% to 5% by weight.

[0085] The binder serves to improve the adhesion between the positive active material particles and the adhesion between the positive active material and the collector. Its specific examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-co-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber or its various copolymers, and any one of them can be used alone or a mixture of two or more thereof. Based on the gross weight of the positive material, the content of the binder can be 1% by weight to 30% by weight, specifically 1% by weight to 10% by weight, more specifically 1% by weight to 5% by weight.

[0086] The separator is used to separate the negative electrode from the positive electrode and provide a mobile path for lithium ions. Any separator can be used without particular restriction, as long as it is commonly used as a separator in a lithium secondary battery. In particular, it is preferred to have a high moisture retention capacity for the electrolyte and a separator with low resistance to the movement of electrolyte ions. Specifically, a porous polymer film can be used, for example, a porous polymer film made of a polyolefin-based polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer and an ethylene / methacrylate copolymer, or a laminated structure of more than two layers thereof. In addition, a typical porous non-woven fabric can be used, such as a non-woven fabric formed by a high melting point glass fiber, a polyethylene terephthalate fiber, etc. In addition, a coated separator containing a ceramic component or a polymer material can be used to ensure heat resistance or mechanical strength, and can be selectively used in a single-layer or multilayer structure.

[0087] As explained above, according to the present disclosure, the unit lithium electrode is protected by the protective film 113 for as long as possible until just before the positive electrode and the separator are stacked, thereby shortening the exposure time of the lithium metal layer 112, and the method of removing the protective film 113 can also minimize the surface damage to the lithium metal layer 112, thereby having better quality.

[0088] Furthermore, the electrode stack manufactured as above may be fabricated into an electrode assembly and then embedded in a battery case together with an electrolyte and then sealed to manufacture a lithium metal battery having excellent quality.

[0089] Since other components of a lithium metal battery are known in the art, description thereof is omitted herein.

[0090] It will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the spirit or scope of the disclosure.

Claims

1. A method for manufacturing a unit lithium electrode, comprising: After the sheet-like lithium metal electrode is cut into the size of a unit lithium electrode, the protective film is removed through an adhesive film having an adhesive layer formed on one side of a substrate film, wherein the sheet-like lithium metal electrode comprises a current collector, a lithium metal layer formed on one side or both sides of the current collector, and a protective film attached to the surface of the lithium metal layer.

2. The method for manufacturing a unit lithium electrode according to claim 1, wherein: The protective film is one selected from the group consisting of a polymer film, a polymer electrolyte membrane, a release film, a vapor deposition film, a metal foil, a glass fiber cloth, and a functional multilayer film.

3. The method for manufacturing a unit lithium electrode according to claim 1, wherein: The method for manufacturing a unit lithium electrode further includes a tab-forming cutting step of forming a tab before, after, or simultaneously with cutting the sheet-like lithium metal electrode into the size of the unit lithium electrode.

4. The method for manufacturing a unit lithium electrode according to claim 1, wherein: The protective film is removed by bringing the adhesive layer of the adhesive film into contact with the surface of the protective film and then peeling it off.

5. The method for manufacturing a unit lithium electrode according to claim 1, wherein: The adhesive layer of the adhesive film is formed on the entire surface of the base film, or is formed in a pattern shape such as a line shape or a dot shape.

6. The method for manufacturing a unit lithium electrode according to claim 1, wherein: In the step of removing the protective film, the adhesive film is used in a form in which both ends are bent in a direction opposite to the protective film.

7. The method for manufacturing a unit lithium electrode according to claim 1, wherein: The method of manufacturing the unit lithium electrode further includes pressing the unit lithium electrode after removing the protective film.

8. The method for manufacturing a unit lithium electrode according to claim 7, wherein: The pressing is performed by a pair of pressing rollers.

9. A method for manufacturing an electrode stack for a lithium metal battery, comprising: A unit lithium electrode is prepared using the method for manufacturing a unit lithium electrode according to claim 1, and is stacked together with a separator, or with a positive electrode and a separator.

10. The method for manufacturing an electrode stack according to claim 9, wherein The electrode stack is a bibattery in which the electrodes at both ends have the same polarity, a full battery in which the electrodes at both ends have different polarities, a single battery in which a separator and a unit lithium electrode are stacked, or a stacked electrode assembly in which two or more positive electrodes are alternately arranged with the unit lithium electrodes with a separator interposed therebetween.

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