Anode, anode sheet and electrode assembly

Abstract

An anode according to various embodiments comprises: a first metal layer formed of a lithium metal; and a second metal layer which is formed of a material other than the lithium metal and which at least partially overlaps and is bonded to the first metal layer, wherein the second metal layer can be interposed between a plurality of the first metal layers, or the first metal layer can be interposed between a plurality of the second metal layers. Other embodiments are possible.

Description

Cathode, cathode sheet, and electrode assembly

[0001] Cross-citation with related applications

[0002] This application is based on and claims the benefit of priority from Korean Patent Application Nos. 10-2024-0065416, 10-2024-0094209 and 10-2025-0065353, filed with the Korean Intellectual Property Office on May 20, 2024, July 17, 2024 and May 20, 2025, respectively, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present application relates to a cathode, a cathode sheet, and an electrode assembly.

[0005] Recently, demand for mobile devices such as smartphones, tablet PCs, and wireless earphones has been increasing. Furthermore, with the development of electric vehicles, energy storage batteries, robots, and satellites in full swing, research is actively underway on high-performance secondary batteries capable of repeated charging and discharging as an energy source.

[0006] Currently commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Among these, lithium secondary batteries offer the advantages of virtually no memory effect compared to nickel-based batteries, allowing for easy charging and discharging, a very low self-discharge rate, and high energy density.

[0007] Meanwhile, lithium metal batteries sometimes use lithium metal as the anode. While lithium metal is beneficial for increasing the battery's energy density, it can be difficult to handle due to its softness and tendency to stick compared to the traditionally used copper (Cu).

[0008] In addition, in order to prevent the problem of lithium metal sticking during the notching process of forming the tab of the negative electrode, there are cases where a release film is added and then pressed with a puncher. However, this is uneconomical because the release film is consumed, and the process speed is slowed down due to deceleration of the puncher, and there may be problems in that the remaining scrap after the punching must be processed separately.

[0009] In addition, when a non-contact method (e.g., using a laser) is used instead of a contact method such as a punching machine during the notching process, lithium dust (hume) may be generated as energy is directly applied to the lithium metal, which may cause safety issues.

[0010] Various embodiments of the present application can provide a negative electrode, a negative electrode sheet, and an electrode assembly that can perform a non-contact notching process to enable an efficient process, do not generate lithium dust, and improve complex problems caused by lithium metal during a subsequent bonding process with a lead.

[0011] According to one embodiment of the present application, a negative electrode includes a first metal layer formed of lithium metal and a plurality of second metal layers formed of a material other than lithium metal and bonded to overlap a portion of the first metal layer, and the first metal layer may be interposed between the plurality of second metal layers.

[0012] In one embodiment of the present application, in the negative electrode, the plurality of second metal layers may be formed of a metal having a lower reactivity than lithium metal.

[0013] In a cathode according to one embodiment of the present application, each of the plurality of second metal layers includes a first region overlapping the first metal layer and a second region that is a region other than the first region, and at least one of the plurality of second metal layers may be formed such that the widthwise length of the first region is shorter than the widthwise length of the second region.

[0014] In a cathode according to one embodiment of the present application, at least one first region of the plurality of second metal layers can be embedded in the first metal layer.

[0015] In a cathode according to one embodiment of the present application, the first region of each of the plurality of second metal layers may have a widthwise length that is substantially the same as each other.

[0016] According to one embodiment of the present application, the cathode may include a cathode tab in at least one second region among the plurality of second metal layers.

[0017] In one embodiment of the present application, the cathode may include a margin region, which is a region other than a region corresponding to the cathode tab, in at least one second region among the plurality of second metal layers.

[0018] According to one embodiment of the present application, a negative electrode may include a plurality of first metal layers formed of lithium metal, a first region formed of a material other than the lithium metal and overlapping at least one of the plurality of first metal layers, and a second region that is a region other than the first region, a second metal layer interposed between the plurality of first metal layers and bonded to the plurality of first metal layers, and a margin region provided adjacent to at least one of the plurality of first metal layers in the second region.

[0019] In the negative electrode according to one embodiment of the present application, the second metal layer may be formed of a metal having a lower reactivity than lithium metal.

[0020] The cathode according to one embodiment of the present application may further include a cathode tab formed in the second region.

[0021] In a cathode according to one embodiment of the present application, when viewed in the thickness direction of one of the first metal layers, at least a portion of the margin region may be provided between the cathode tab and one of the first metal layers, or between the cathode tab and the first region.

[0022] In one embodiment of the present application, in the cathode, at least a portion of the first region of the second metal layer may include one or more of a predetermined pattern structure and a surface-treated region.

[0023] In a cathode according to one embodiment of the present application, the widthwise length of the first region of the second metal layer may be formed to be shorter than the widthwise length of the second region.

[0024] According to one embodiment of the present application, a negative electrode sheet includes a first metal layer and a second metal layer that overlaps and is bonded to a portion of one edge of the first metal layer, the second metal layer includes a first region that overlaps the first metal layer and a second region that is a region other than the first region, and a negative electrode tab including a first tab, a second tab, and a third tab is formed in the second region, and the second tab and the third tab that are adjacent to each other on both sides with respect to the first tab are each positioned to be spaced apart from the first tab by a predetermined distance, and a first length that is a distance between the first tab and the second tab can be formed to be longer than a second length between the first tab and the third tab.

[0025] In a cathode sheet according to one embodiment of the present application, the second metal layer may be formed of a metal having lower reactivity than the first metal layer.

[0026] An electrode assembly according to one embodiment of the present application includes a positive electrode, a negative electrode, and a separator, and the negative electrode includes a first metal layer formed of lithium metal and a second metal layer formed by overlapping and bonding a portion of one edge of the first metal layer, the second metal layer is formed of a metal having a lower reactivity than lithium metal, the negative electrode is interposed between two separators to form a negative electrode structure, and the negative electrode structure includes a stack portion and a folding portion, and the electrode assembly may have a structure in which the stack portion and the positive electrode are alternately and sequentially stacked.

[0027] In an electrode assembly according to one embodiment of the present application, each of the stack portion and the folding portion may be provided in multiple units.

[0028] In an electrode assembly according to one embodiment of the present application, the cathode includes a plurality of second metal layers, and the first metal layer can be interposed between the plurality of second metal layers.

[0029] In an electrode assembly according to one embodiment of the present application, the cathode includes a plurality of first metal layers, and the second metal layer can be interposed between the plurality of first metal layers.

[0030] In an electrode assembly according to one embodiment of the present application, the positive electrode includes a positive electrode active material layer including a positive electrode active material and a positive electrode current collector supporting the positive electrode active material layer, and the positive electrode active material may include a sulfur compound.

[0031] According to various embodiments of the present disclosure, an anode, anode sheet, or an electrode assembly can be provided that maximizes energy density while minimizing defects that may occur during the manufacturing process of a battery using lithium metal as the main anode material. For example, a non-contact notching process can be performed to enable efficient processing, prevent the generation of lithium dust, and improve complex problems caused by lithium metal during subsequent lead bonding.

[0032] The drawings shown in this application are according to an embodiment of this application, and the ratio of the width, width, or thickness (or height) of each component is for the purpose of explaining this application in detail, and these ratios may differ from the actual ones. In addition, in the coordinate system shown in the drawings, each axis may be perpendicular to each other, and the direction pointed by the arrow may be the + direction, and the direction opposite to the direction pointed by the arrow (the direction rotated by 180 degrees) may be the - direction.

[0033] FIG. 1 is a plan view illustrating at least a portion of a cathode according to one embodiment of the present application.

[0034] FIG. 2 and FIG. 3 illustrate a part of the manufacturing process of a negative electrode sheet according to the first embodiment of the present application.

[0035] Figures 4 to 6 illustrate a part of the manufacturing process of a negative electrode sheet according to the second embodiment of the present application.

[0036] FIG. 7 illustrates a part of the manufacturing process of a negative electrode sheet according to the third embodiment of the present application.

[0037] FIG. 8 illustrates a part of the manufacturing process of a negative electrode sheet according to one embodiment of the present application.

[0038] FIG. 9 is a plan view of FIG. 8, illustrating a part of the manufacturing process of a negative electrode sheet according to one embodiment of the present application.

[0039] FIG. 10 is a plan view illustrating at least a portion of a cathode sheet according to one embodiment of the present application.

[0040] Fig. 11 is a plan view exemplarily showing a process of forming a cathode by cutting a cathode sheet in one embodiment of the present application.

[0041] FIG. 12 is a plan view illustrating at least a portion of a cathode according to one embodiment of the present application.

[0042] FIG. 13 and FIG. 14 illustrate a part of the manufacturing process of a negative electrode sheet according to the fourth embodiment of the present application.

[0043] Figures 15 to 17 illustrate a part of the manufacturing process of a negative electrode sheet according to the fifth embodiment of the present application.

[0044] FIG. 18 illustrates a part of the manufacturing process of a negative electrode sheet according to the sixth embodiment of the present application.

[0045] FIG. 19 and FIG. 20 illustrate a part of the manufacturing process of a negative electrode sheet according to one embodiment of the present application.

[0046] FIG. 21 is a plan view of FIG. 20, illustrating a part of the manufacturing process of a negative electrode sheet according to one embodiment of the present application.

[0047] FIG. 22 is a plan view illustrating at least a portion of a cathode sheet according to one embodiment of the present application.

[0048] Fig. 23 is a plan view exemplarily showing a process of forming a cathode by cutting a cathode sheet in one embodiment of the present application.

[0049] FIG. 24 is a plan view illustrating at least a portion of a cathode according to one embodiment of the present application.

[0050] FIG. 25 and FIG. 26 illustrate a part of the manufacturing process of a negative electrode sheet according to the seventh embodiment of the present application.

[0051] Figures 27 to 29 illustrate a part of the manufacturing process of a negative electrode sheet according to the eighth embodiment of the present application.

[0052] FIG. 30 illustrates a part of the manufacturing process of a negative electrode sheet according to the ninth embodiment of the present application.

[0053] FIG. 31 and FIG. 32 illustrate a part of the manufacturing process of a negative electrode sheet according to one embodiment of the present application.

[0054] FIG. 33 is a plan view of FIG. 32, illustrating a part of the manufacturing process of a negative electrode sheet according to one embodiment of the present application.

[0055] FIG. 34 is a plan view illustrating at least a portion of a cathode sheet according to one embodiment of the present application.

[0056] Fig. 35 is a plan view exemplarily showing a process of forming a cathode by cutting a cathode sheet in one embodiment of the present application.

[0057] FIG. 36 is a plan view illustrating at least a portion of an electrode assembly according to one embodiment of the present application.

[0058] Before proceeding with a detailed description of this application, it should be noted that terms and words used in this specification and claims may not be interpreted solely based on their conventional or dictionary meanings. Furthermore, inventors should interpret terms and concepts in a way that aligns with the technical concept of this application, based on the principle that the inventor can appropriately define the concept of a term to best explain his or her invention. The embodiments described in this specification and the configurations depicted in the drawings represent only the most preferred embodiments of this application and may not represent the entire technical concept of this application. Therefore, various equivalents and variations may exist at the time of filing of this application.

[0059] The same reference numbers or symbols in each drawing attached to this specification may indicate parts or components that perform substantially the same functions. For convenience of explanation and understanding, the same reference numbers or symbols may be used in different embodiments. In other words, even if components with the same reference numbers are depicted in multiple drawings, they may not all represent a single embodiment.

[0060] In the following description, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms such as "comprise" or "comprises" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but are to be understood as not excluding in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0061] In addition, in the description below, expressions such as upper, upper, lower, lower, side, front, and rear are expressed based on the direction shown in the drawing, and may be expressed differently if the direction of the object is changed.

[0062] Additionally, terms containing ordinal numbers following a dash, such as "1-1" and "1-2," may be used in this specification and claims to distinguish between components. These ordinals may be used to distinguish identical or similar components from each other, and the use of such ordinals should not be interpreted in a limited manner. For example, components associated with such ordinals should not be interpreted in a limited manner, such as in the order of use or arrangement, based on their numbers.

[0063] In this specification, the term "battery" may be used with the same meaning as "cell." Furthermore, the terms "battery" and "cell" may collectively refer to a battery cell, which is a unit thereof, or a battery module or battery pack containing a battery cell.

[0064] The present application can provide at least one of a negative electrode, a negative electrode sheet, and an electrode assembly that can perform a non-contact notching process to enable an efficient process, does not generate lithium dust, and can improve complex problems caused by lithium metal during a subsequent process of joining with a lead.

[0065] FIG. 1 is a plan view illustrating at least a portion of a cathode (10) according to one embodiment of the present application.

[0066] According to one embodiment, the cathode (10) may include a first metal layer (100) and a second metal layer (200).

[0067] In the cathode (10) according to one embodiment, the second metal layer (200) can be formed by overlapping a portion of the first metal layer (100).

[0068] For example, the second metal layer (200) may protrude in one direction from one edge of the first metal layer (100).

[0069] Also, for example, in the cathode (10), the second metal layer (200) can be formed by overlapping with a portion of one edge of the first metal layer (100).

[0070] In the cathode (10) according to one embodiment, the second metal layer (200) may be formed of a metal having a lower reactivity than the first metal layer (100).

[0071] For example, the first metal layer (100) may be formed of lithium metal (Li metal). The second metal layer (200) may be formed of a material other than lithium metal.

[0072] For example, the second metal layer (200) may be formed of another metal having lower reactivity than lithium (Li) metal.

[0073] For example, the second metal layer (200) may be formed of at least one material among copper (Cu), nickel (Ni), or stainless steel.

[0074] In one embodiment, the second metal layer (200) may have various structures. Each of the second metal layers (200) may include one or more of a predetermined pattern structure and a surface-treated region. One or more of the predetermined pattern structure and the surface-treated region may be included in at least a portion of the first region (210).

[0075] For example, at least a portion of the second metal layer (200) (e.g., at least a portion of the area in contact with the first metal layer (100)) may include a predetermined pattern structure. The pattern structure may be, for example, a mesh structure, a structure having a grid pattern formed on the surface, or may have both of these structures. For example, a mesh structure may refer to a structure in which a plurality of holes are formed, and a grid pattern may refer to a structure in which a plurality of grooves are formed. Through this, the contact area between the first metal layer (100) and the second metal layer (200) may be maximized, thereby improving the bonding strength.

[0076] In addition, at least a portion of the second metal layer (200) (e.g., at least a portion of the area of ​​the second metal layer (200) that contacts the first metal layer (100)) may be surface-treated. The surface treatment may be performed, for example, by plasma treatment, etc. If surface-treated, the surface may have a different surface roughness from other areas. Through such an appropriate surface treatment, the bonding strength between the first metal layer (100) and the second metal layer (200) may be improved. In the present specification, reactivity may mean a property of being oxidized to become a cation, and low reactivity may mean a relatively low tendency to become a cation.

[0077] Meanwhile, in the cathode (10) according to one embodiment, the second metal layer (200) may be formed of a metal material that does not easily react when in contact with the first metal layer (100).

[0078] For example, the second metal layer (200) may not include aluminum (Al) that can undergo an alloying reaction with lithium metal. In the present specification, not including a specific material means substantially not including it, and substantially not including it preferably means 0 wt%, but may mean including it in an amount of 1 wt% or less, 0.5 wt% or less, or 0.1 wt% or less relative to the total weight.

[0079] In the cathode (10) according to one embodiment, the second metal layer (200) may include a first region (210) overlapping with the first metal layer (100) (e.g., overlapping region) and a second region (220) (e.g., non-overlapping region) which is a region other than the first region (210). For example, based on the thickness direction of the first metal layer (100) (e.g., +Z-axis direction of FIG. 1), the second metal layer (200) may include a first region (210) overlapping with the first metal layer (100) (e.g., overlapping region) and a second region (220) (e.g., non-overlapping region) which is a region other than the first region (210) (i.e., a region not overlapping with the first metal layer (100).

[0080] That is, in this specification, unless otherwise specified, the first region (210) of the second metal layer (200) may mean an overlapping region in which a plurality of configurations are overlapped, and the second region (220) of the second metal layer (200) may mean a non-overlapping region that is a region other than the first region (210).

[0081] In the present specification, the thickness of the first metal layer (100) is not particularly limited, but may be, for example, about 10 µm to 200 µm, 15 µm to 180 µm, 20 µm to 150 µm, 25 µm to 130 µm, 30 µm to 100 µm, 35 µm to 80 µm, or 40 µm to 60 µm for free-standing. In addition, in the present specification, the thickness of the second metal layer (200) is not particularly limited, but may be, for example, about 5 µm to 20 µm, 6 µm to 18 µm, 7 µm to 16 µm, 8 µm to 14 µm, or 9 µm to 12 µm for improving energy density, or may be 10 µm or less. In this specification, thickness may mean the length along the thickness direction described above (e.g., the +Z axis direction in FIG. 1) unless otherwise defined.

[0082] In one example, the thickness of the first metal layer (100) may be greater than the thickness of the second metal layer (200). Through this, the tensile strength of the cathode (10) can be improved.

[0083] According to one embodiment, the length (W1) of the first region (210) in the first direction (e.g., width direction) (e.g., +Y-axis direction of FIG. 1) may be shorter than the length (W2) of the second region (220) in the first direction (e.g., width direction).

[0084] For example, if the width direction length (W1) of the first region (210) is excessively short, it may be difficult to secure bonding stability between the first metal layer (100) and the second metal layer (200), and conversely, if it is excessively long, unnecessary manufacturing costs may be consumed and the energy density of the battery may be lowered. Accordingly, the width direction length (W1) of the first region (210) according to one embodiment may be about 0.5 mm to 20 mm.

[0085] For example, the widthwise length (W2) of the second region (220) may be longer than the minimum length (e.g., about 8 mm) of the negative tab (e.g., see 230 of FIG. 10) required for bonding with the negative lead. In this way, when the widthwise length (W2) of the second region (220) in the negative electrode (10) according to one embodiment is formed to be longer than the minimum required length of the negative tab, the process for forming the negative tab is performed only in the second region (220), and a separate process for forming the negative tab is not performed in the first region (210), thereby preventing damage to the first metal layer (100).

[0086] In a cathode (10) according to one embodiment, the ratio (W2 / W1) of the width direction length (W2) of the second region (220) and the width direction length (W1) of the first region (210) may be greater than 1 and less than or equal to 20.

[0087] In a cathode (10) according to another embodiment, the ratio (W2 / W1) of the width direction length (W2) of the second region (220) and the width direction length (W1) of the first region (210) may be 2 or more and 18 or less.

[0088] In another embodiment, in the cathode (10), the ratio (W2 / W1) of the width direction length (W2) of the second region (220) and the width direction length (W1) of the first region (210) may be 5 or more and 16 or less.

[0089] According to various embodiments of the present disclosure, the ratio (W2 / W1) of the widthwise length (W2) of the second region (220) and the widthwise length (W1) of the first region (210) in the cathode (10) satisfies a predetermined range, thereby minimizing the size of the cathode (10) while maximizing the capacity.

[0090] In the cathode (10) according to one embodiment, the width direction length (W1) of the first region (210) and the width direction length (W) of the entire second metal layer (200) T ) ratio (W1 / W T ) can be between 0.01 and 0.1.

[0091] In the cathode (10) according to one embodiment, the width direction length (W1) of the first region (210) and the width direction length (W) of the entire second metal layer (200) T ) ratio (W1 / W T ) can be 0.02 to 0.09.

[0092] In the cathode (10) according to one embodiment, the width direction length (W1) of the first region (210) and the width direction length (W) of the entire second metal layer (200) T ) ratio (W1 / W T ) can be 0.03 to 0.08.

[0093] In the cathode (10) according to one embodiment, the width direction length (W1) of the first region (210) and the width direction length (W) of the entire second metal layer (200) T ) ratio (W1 / W T) can be 0.04 to 0.07.

[0094] In various embodiments of the present disclosure, the width direction length (W1) of the first region (210) and the width direction length (W) of the entire second metal layer (200) T ) ratio (W1 / W T ) can secure sufficient bonding strength between the first metal layer (100) and the second metal layer (200) by satisfying certain range conditions.

[0095] In a cathode (10) according to one embodiment, the first region (210) of the second metal layer (200) can be embedded in the first metal layer (100).

[0096] For example, the first surface (e.g., the upper surface) of the second metal layer (200) and the first surface (e.g., the upper surface) of the first metal layer (100) may be formed to be positioned on substantially the same plane.

[0097] For example, the second metal layer (200) may have a first region (210) embedded in the first metal layer (100), so that there may not be an upper step between the second metal layer (200) and the first metal layer (100).

[0098] Through this form, even when the first metal layer (100) and the second metal layer (200) are joined and then rewinded, the problem of meandering movement, in which the alignment between the two metal layers (100, 200) is misaligned, as well as the problem of the electrode being twisted due to meandering, can be effectively prevented.

[0099] In addition, when unwinding is performed to manufacture a cathode structure (e.g., see 10A of FIG. 36) to be described later after being rewound as described above through this form, the problem of the first metal layer (100) and the second metal layer (200) being twisted can be prevented.

[0100] In addition, through this form, when there is a step between the upper surface of the first metal layer (100) and the second metal layer (200) (especially, when it is thicker than the thickness of the anode (see 30 of FIG. 36) to be described later), the stack portion (10A_S) of the cathode structure (see, for example, the cathode structure (10A) of FIG. 36) can be prevented from excessively protruding, thereby reducing the energy density per volume of the battery cell.

[0101] In the cathode (10) according to one embodiment, a cathode tab (see 230 of FIG. 10) may be formed in the second region (220) of the second metal layer (200). For example, the cathode tab (see 230 of FIG. 10) may be formed by performing a notching process on the second region (220) of the second metal layer (200). That is, the cathode (10) may include a cathode tab (see 230 of FIG. 10) formed in the second region (220) of the second metal layer (200).

[0102] In one embodiment, the cathode (10) may be formed with a plurality of cathode tabs (see 230 in FIG. 10). Here, the notching process is not particularly limited, but may be performed by a contact method such as a puncher or a non-contact method using a laser. The cathode (10) may include a plurality of cathode tabs (230 in FIG. 10) formed in the second region (220) of the second metal layer (200).

[0103] In various embodiments, the second metal layer (200) is formed of a metal having relatively low reactivity compared to lithium metal, so that even if the notching process is performed in a non-contact manner, the occurrence of safety issues due to dust can be minimized.

[0104] Meanwhile, the negative electrode (10) according to various embodiments of the present disclosure may mean a negative electrode sheet (e.g., a negative electrode sheet (10S) of FIG. 10) used to manufacture a plurality of electrode assemblies, or may mean a negative electrode sheet cut to a certain size used to manufacture one electrode assembly or one battery cell, i.e., a portion of the negative electrode sheet.

[0105] FIG. 2 and FIG. 3 illustrate a part of the manufacturing process of a negative electrode sheet (see 10S of FIG. 10) according to the first embodiment of the present application.

[0106] Meanwhile, the manufacturing process of the negative electrode sheet (see 10S of FIG. 10) may be performed in at least some processes using a roll-to-roll method. The roll-to-roll method may be one of the continuous processes that processes a sheet-shaped material to have a new function by applying tension to it using a roll (e.g., an unwinding roll and a rewinding roll, etc.). The roll-to-roll method may be advantageous for mass production because it continuously processes the material. The description of the negative electrode (10) described in the present specification may be referred to the description of the negative electrode sheet (see 10S of FIG. 10) unless there is a contradiction.

[0107] According to one embodiment, the first metal layer (100) may be in the form of a sheet and may be transported in a specific direction via a transport roll (not shown). For example, referring to FIG. 2, the first metal layer (100) may be transported in the +X direction.

[0108] Unless otherwise specified herein, the direction parallel to the direction in which the first metal layer (100) is transported may be referred to as the machine direction (MD). For example, in FIG. 2, the machine direction of the first metal layer (100) may be the +X direction (or -X direction). In addition, unless otherwise specified herein, the direction perpendicular to the machine direction (MD) on a plane parallel to the first metal layer (100) may be referred to as the transverse direction (TD). For example, in FIG. 2, the transverse direction of the first metal layer (100) may mean the +Y direction (or -Y direction).

[0109] According to one embodiment, the second metal layer (200) may be in the form of a sheet. For example, the second metal layer (200) may be positioned on the first metal layer (100) so as to overlap a portion of one edge of the first metal layer (100) and may be transported in the same direction (i.e., machine direction) as the first metal layer (100) through a transport roll (not shown). For example, referring to FIG. 2, the second metal layer (200) may be transported in the +X direction, similar to the direction in which the first metal layer (100) is transported.

[0110] A method for manufacturing a cathode sheet according to one embodiment (see 10S of FIG. 10) may include providing a first metal layer (100) and a second metal layer (200). At least one of the first metal layer (100) and the second metal layer (200) may be provided in the roll-to-roll manner described above.

[0111] In one embodiment, referring to FIG. 3, the first metal layer (100) and the second metal layer (200) can be simultaneously rolled by a roller (R). Specifically, the roller (R) can apply pressure to the overlapping area of ​​the first metal layer (100) and the second metal layer (200) to join them. The roller (R) can be positioned in the thickness direction (e.g., +Z-axis direction) of the overlapping portion of the first metal layer (100) and the second metal layer (200) to simultaneously press the first metal layer (100) and the second metal layer (200). Meanwhile, unless otherwise limited in the present specification, the thickness direction can be perpendicular to both the machine direction (MD) and the vertical direction (TD).

[0112] FIGS. 4 to 6 illustrate a part of the manufacturing process of a negative electrode sheet (see 10S of FIG. 10) according to the second embodiment of the present application.

[0113] Referring to FIG. 4, in a method for manufacturing a cathode sheet according to one embodiment, a roller (R) may roll a portion of one edge area of ​​a first metal layer (100) that is transported in the +X axis direction. In this case, unlike what was described with reference to FIG. 3, the object rolled by the roller (R) may be the first metal layer (100) before being overlapped with the second metal layer (200).

[0114] Referring to FIG. 5, a groove (H) can be formed in the first metal layer (100) by the pressure of the roller (R), and a second metal layer (200) can be positioned at a position corresponding to the formed groove (H).

[0115] Referring to FIG. 6, after a second metal layer (200) is placed in a groove (H) of a first metal layer (100), the first metal layer (100) and the second metal layer (200) can be mutually bonded by a bonding means such as a laser device (LA). In FIG. 6, the laser device (LA) is exemplarily illustrated as a bonding means, but other bonding means in various embodiments of the present disclosure are not limited thereto, and a welding device or the like may be used as the bonding means.

[0116] FIG. 7 illustrates a part of the manufacturing process of a negative electrode sheet (see 10S of FIG. 10) according to the third embodiment of the present application.

[0117] Referring to FIG. 7, in a cathode sheet according to various embodiments, a first metal layer (100) and a second metal layer (200) can be bonded using a binder (B). For example, as shown in FIG. 4, after a roller (R) rolls a portion of one edge area of ​​the first metal layer (100), a binder (B) can be applied onto a groove (H) formed by the rolling, and a second metal layer (200) can be placed at a position corresponding to the groove (H) where the binder (B) is applied, thereby bonding the first metal layer (100) and the second metal layer (200).

[0118] In an embodiment, the binder (B) may be formed of a material that can have a predetermined adhesive strength without chemically reacting with at least one of the first metal layer (100) and the second metal layer (200).

[0119] Binder (B) is, for example, polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethylmethacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, It may include at least one selected from the group consisting of cyanoethylcellulose, cyanoethylsucrose, pullulan, carboxyl methyl cellulose, acrylonitrile-styrenebutadiene copolymer, polyimide, and styrene butadiene rubber (SBR).

[0120] FIG. 8 illustrates a part of a manufacturing process of a negative electrode sheet (10S) according to one embodiment of the present application. Unless otherwise limited in the present specification, the negative electrode sheet (10S) may mean a state in which a first metal layer (100) and a second metal layer (200) are bonded. Here, the bonded state may not simply mean a state in which the first metal layer (100) and the second metal layer (200) are in surface contact, but may mean a state in which the second metal layer (200) is attached to the first metal layer (100) by a mechanical or chemical bonding method (e.g., rolling, laser bonding, binder bonding, etc.).

[0121] FIG. 9 is a plan view of FIG. 8, illustrating a part of the manufacturing process of a negative electrode sheet (10S) according to one embodiment of the present application.

[0122] Referring to FIG. 8, according to one embodiment, a first metal layer (100) and a second metal layer (200) can be bonded to each other to form a bonding boundary line (CL).

[0123] A method for manufacturing a cathode sheet (10S) according to one embodiment may include a step of bonding a first metal layer (100) and a second metal layer (200) to each other and a step of bonding the first metal layer (100) and the second metal layer (200) to each other to form a bonding boundary line (CL).

[0124] The bonding boundary line (CL) may correspond to, for example, an end portion of the first metal layer (100) that overlaps with the second metal layer (200). For example, the bonding boundary line (CL) may correspond to a line that overlaps with the second metal layer (200) among the ends of the first metal layer (100) based on the thickness direction of the first metal layer (100) (e.g., the +Z-axis direction of FIG. 8).

[0125] Referring to FIGS. 8 and 9, a notching process can be performed on a cathode sheet (10S) according to one embodiment using a laser device (LA).

[0126] For example, a laser (L) generated from a laser device (LA) can be irradiated to a second region (220) of a second metal layer (200), whereby the second region (220) can be partially cut to form a cathode tab (see 230 in FIG. 10).

[0127] Fig. 10 is a plan view illustrating at least a portion of a negative electrode sheet (10S) according to one embodiment of the present application. Fig. 11 is a plan view exemplarily illustrating a state in which a negative electrode sheet (see 10S of Fig. 10) is cut to form a negative electrode (10) according to one embodiment of the present application.

[0128] According to one embodiment, a negative electrode sheet (10S) may have a negative electrode tab (230) formed in a second region (220) that includes a first tab (231), a second tab (232), and a third tab (233). That is, the negative electrode sheet (10S) according to one embodiment may include a negative electrode tab (230) formed in the second region (220).

[0129] For example, the second tab (232) and the third tab (233), which are adjacent to each other on both sides of the first tab (231), may be positioned at a predetermined distance from the first tab (231).

[0130] For example, the first length (W) is the gap between the first tab (231) and the second tab (232). 12 ) is the second length (W) between the first tab (231) and the third tab (233). 13 ) can be formed longer than the tabs. This structure can be advantageous in aligning the tabs when manufacturing a cathode structure (see 10A of FIG. 36) including a folding portion and a stack portion, which will be described later, by making the distance between the tabs different.

[0131] Meanwhile, the negative electrode sheet (10S) according to one embodiment may further include a margin region (235) which is a region other than the region corresponding to the negative electrode tab (230) in the second region (220). Referring to FIG. 10, at least a portion of the margin region (235) may be provided between the negative electrode tab (230) and the first metal layer (100). For example, when viewed in the thickness direction of the first metal layer (100) (i.e., +Z-axis direction), at least a portion of the margin region (235) may be provided between the negative electrode tab (230) and the first metal layer (100). In addition, referring to FIG. 10, at least a portion of the margin region (235) may be provided between the negative electrode tab (230) and the first region (210).

[0132] For example, when viewed in the thickness direction of the first metal layer (100) (i.e., +Z-axis direction), at least a portion of the margin region (235) may be provided between the negative tab (230) and the first region (210). That is, referring to FIG. 10, the first region (210) may be provided between the margin region (235) and the first metal layer (100). When viewed in the thickness direction of the first metal layer (100) (i.e., +Z-axis direction), the first region (210) may be provided between the margin region (235) and the first metal layer (100). Through this, even if the manufacturing process of the negative electrode sheet (10S) is performed in a roll-to-roll manner, elongation of the first metal layer (100), which is a lithium metal, in the machine direction (MD) is suppressed, so that an advantageous effect can be obtained during the continuous notching process.

[0133] In other words, the negative electrode sheet (10S) according to one embodiment may include a margin region (235) that is a part of the second region (220). For example, the margin region (235) may be provided adjacent to the first metal layer (100). Here, the margin region (235) may be a region other than a region in which the negative electrode tab (230) is formed by the notching process in the second region (220). In addition, the negative electrode sheet (10S) here may be in a state in which the negative electrode tab (230) is not formed, and a plurality of negative electrode sheets (10S) may be laminated in one direction (for example, the thickness direction of the first metal layer (100) (i.e., the +Z-axis direction)) or in a curved state (folded) to form the negative electrode tab (230) at once by performing the notching process. This simplifies the process and minimizes tab alignment mismatch that occurs when forming the negative tab (230) in advance. This effect can be particularly noticeable in bidirectional batteries.

[0134] A bidirectional battery may refer to a battery in which a positive tab (not shown) connected to a positive electrode (e.g., see the positive electrode (30) of FIG. 36) and a negative tab (230) protrude in different directions from one side of a body portion of an electrode assembly (e.g., see the electrode assembly (1) of FIG. 36). In addition, a bidirectional battery may refer to a battery in which a positive lead connected to one or more positive tabs and protrudes from one side of a body portion of an electrode assembly (e.g., see the electrode assembly (1) of FIG. 36) and a negative lead connected to one or more negative tabs (230) and protrudes from one side of a body portion of the electrode assembly face different directions.

[0135] According to one embodiment, the negative electrode sheet (10S) may be cut according to a predetermined rule using a cutter (not shown). The predetermined rule is not limited, but may be, for example, for standardizing the negative electrode (10) to be formed, and reference may be made to FIG. 11. The cutter may apply, for example, one or more of a blade contact cutting method and a laser non-contact cutting method, but is not limited thereto. For example, referring to FIG. 11, the negative electrode sheet (10S) may be cut along a vertical direction (TD) (e.g., +Y axis direction), thereby forming individual negative electrodes (10).

[0136] A method for manufacturing a cathode (10) according to one embodiment may include the method for manufacturing a cathode sheet (10S) described above. The method for manufacturing a cathode (10) may include cutting a cathode sheet (10S).

[0137] According to one embodiment, the negative electrode (10) may include a margin region (235) in the second region (220) other than the negative electrode tab (230). Referring to FIG. 11, at least a portion of the margin region (235) may be provided between the negative electrode tab (230) and the first metal layer (100). When viewed in the thickness direction of the first metal layer (100) (i.e., the +Z-axis direction), at least a portion of the margin region (235) may be provided between the negative electrode tab (230) and the first metal layer (100). In addition, referring to FIG. 11, at least a portion of the margin region (235) may be provided between the negative electrode tab (230) and the first region (210). When viewed in the thickness direction of the first metal layer (100) (i.e., +Z-axis direction), at least a portion of the margin region (235) may be provided between the negative tab (230) and the first region (210). That is, referring to FIG. 11, the first region (210) may be provided between the margin region (235) and the first metal layer (100). When viewed in the thickness direction of the first metal layer (100) (i.e., +Z-axis direction), the first region (210) may be provided between the margin region (235) and the first metal layer (100). Through this, the first metal layer (100), which is lithium metal, may be protected during the notching process, thereby improving process stability, and the tensile strength of the negative electrode (10) may be improved. In addition, through the margin region (235), it is possible to prevent lithium dendrites from directly contacting the positive electrode tab connected to the positive electrode (see 30 in FIG. 36), thereby causing a short circuit. In particular, it is possible to effectively prevent the occurrence of a short circuit even in a unidirectional battery in which the positive electrode tab and the negative electrode tab (230) face the same direction.

[0138] A unidirectional battery may refer to a battery in which the positive electrode tab and the negative electrode tab (230) protrude from one side of the body portion of the electrode assembly (see 1 in FIG. 36) and face in the same direction. In another example, a unidirectional battery may refer to a battery in which a positive electrode lead protrudes from one side of the body portion of the electrode assembly (see 1 in FIG. 36) and is connected to one or more positive electrode tabs and a negative electrode lead protrudes from one side of the body portion of the electrode assembly (see 1 in FIG. 36) and is connected to one or more negative electrode tabs (230) and is connected to one or more negative electrode tabs ...

[0139] Meanwhile, as shown in FIG. 11, cutting the negative electrode sheet (10S) so that two tabs (230) are included in one negative electrode (10) is merely exemplary, and according to another embodiment, the negative electrode sheet (10S) may be formed with cutting points in units of three or more tabs (e.g., ten) to facilitate the formation of a negative electrode structure (10A) such as FIG. 36 described later.

[0140] For example, the negative electrode sheet (10S) may be cut into predetermined units after forming an electrode assembly (e.g., electrode assembly (1) of FIG. 36) by interposing an anode (e.g., anode (30) of FIG. 36) between two surfaces formed by forming a bend. Alternatively, as another example, the negative electrode sheet (10S) may be cut in advance at a stage before interposing an anode.

[0141] FIG. 12 is a plan view illustrating at least a portion of a cathode (10) according to one embodiment of the present application.

[0142] According to one embodiment, the cathode (10) may include a plurality of second metal layers (e.g., a 2-1 metal layer (200a) and a 2-2 metal layer (200b)).

[0143] According to one embodiment, the first metal layer (100) in the cathode (10) may be interposed between a plurality of second metal layers (e.g., the 2-1 metal layer (200a) and the 2-2 metal layer (200b)).

[0144] For example, a cathode (10) according to an example may include a first metal layer (100) and a second metal layer (200) including a second-1 metal layer (200a) and a second-2 metal layer (200b).

[0145] For example, each of the 2-1 metal layer (200a) and the 2-2 metal layer (200b) may be formed by overlapping with a portion of the 1st metal layer (100). Each of the 2-1 metal layer (200a) and the 2-2 metal layer (200b) may protrude in one direction from one edge of the 1st metal layer (100).

[0146] For example, in the cathode (10), each of the 2-1 metal layer (200a) and the 2-2 metal layer (200b) can be bonded and formed by overlapping a portion of one edge of the 1st metal layer (100).

[0147] In a cathode (10) according to one embodiment, the first metal layer (100) may be interposed between the 2-1 metal layer (200a) and the 2-2 metal layer (200b).

[0148] In the cathode (10) according to one embodiment, the second-first metal layer (200a) and the second-second metal layer (200b) may be formed to overlap with a portion of the first metal layer (100) and be bonded. For example, each of the plurality of second metal layers (e.g., the second-first metal layer (200a) and the second-second metal layer (200b)) may protrude in one direction from one edge of the first metal layer (100).

[0149] According to various embodiments, each of the plurality of second metal layers (e.g., the second-first metal layer (200a) and the second-second metal layer (200b)) may refer to the contents of the second metal layer (200) described above, as long as they are not contradictory.

[0150] In an example, in a cathode (10), a first metal layer (100) is interposed between a plurality of second metal layers (e.g., a 2-1 metal layer (200a) and a 2-2 metal layer (200b)), thereby improving the tensile strength of the cathode (10).

[0151] For example, the plurality of second metal layers (e.g., the 2-1 metal layer (200a) and the 2-2 metal layer (200b)) may be formed of another metal having a lower reactivity than lithium (Li) metal.

[0152] For example, the plurality of second metal layers (e.g., 200a, 200b) may be formed of at least one material selected from the group consisting of copper (Cu), nickel (Ni), and stainless steel.

[0153] In one embodiment, the second metal layers (e.g., 200a, 200b) may each independently have various structures. The second metal layers (e.g., 200a, 200b) may each include one or more of a predetermined pattern structure and a surface-treated region. One or more of the predetermined pattern structure and the surface-treated region may be included in the first region (210a, 210b) of the second metal layers (e.g., 200a, 200b).

[0154] For example, the second metal layers (e.g., 200a, 200b) may each independently include a predetermined pattern structure in at least a portion of the region (e.g., at least a portion of the region in contact with the first metal layer (100). The pattern structure may be, for example, a mesh structure, a structure in which a grid pattern is formed on the surface, or may have both of these structures. For example, the mesh structure may mean a structure in which a plurality of holes are formed, and the grid pattern may mean a structure in which a plurality of grooves are formed. Through this, the contact area between the first metal layer (100) and the second metal layer (e.g., 200a, 200b) may be maximized, thereby improving the bonding strength.

[0155] Additionally, at least a portion of the second metal layer (e.g., 200a, 200b) (e.g., at least a portion of the portion of the second metal layer (e.g., 200a, 200b) that contacts the first metal layer (100)) may be surface-treated. The surface treatment may be performed, for example, by plasma treatment or the like. When the surface is treated, the surface may have a different surface roughness from other regions. Through such an appropriate surface treatment, the bonding strength between the first metal layer (100) and the second metal layer (e.g., 200a, 200b) may be improved.

[0156] In one embodiment, each of the plurality of second metal layers (e.g., the 2-1 metal layer (200a) and the 2-2 metal layer (200b)) may include a first region (210a, 210b) that overlaps with the first metal layer (100) (e.g., an overlapping region) and a second region (220a, 220b) that is a region other than the first region (210a, 210b) (e.g., a non-overlapping region). For example, based on the thickness direction of the first metal layer (100) (e.g., the +Z-axis direction of FIG. 12), each of the plurality of second metal layers (e.g., the 2-1 metal layer (200a) and the 2-2 metal layer (200b)) may include a first region (210a, 210b) overlapping with the first metal layer (100) (e.g., an overlapping region) and a second region (220a, 220b) (e.g., a non-overlapping region) other than the first region (210a, 210b).

[0157] In one embodiment, at least one of the plurality of second metal layers (e.g., the 2-1 metal layer (200a) and the 2-2 metal layer (200b)) has a widthwise length (W) of a first region (210a, 210b) (e.g., an overlapping region) that overlaps the first metal layer (100). a1 , W b1 ) is the width direction length (W) of the second region (220a, 220b) (e.g., non-overlapping region) other than the first region (210a, 210b) a2 , W b2 ) can be formed shorter than the original.

[0158] In the second-1 metal layer (200a) of one embodiment, the width direction length (W) of the first region (210a) a1 ) is the width direction length (W) of the second region (220a) a2 ) may be shorter than the width direction length (W) of the first region (210b) in the second-2 metal layer (200b). b1 ) is the width direction length (W) of the second region (220b) b2 ) may be shorter than the width direction length (W) of the first region (210a, 210b) a1 , W b1 ) is the width direction length (W) of the second region (220a, 220b) a2 , W b2 ) can be made shorter, thereby maximizing the capacity while minimizing the size of the cathode (10).

[0159] In the second-1 metal layer (200a) according to one embodiment, the width direction length (W) of the second region (220a) a2 ) and the width direction length (W) of the first region (210a) a1 ) ratio (W a2 / W a1 ) may be greater than 1 and less than or equal to 20, greater than or equal to 2 and less than or equal to 18, or greater than or equal to 5 and less than or equal to 16. In addition, in the second-second metal layer (200b), the width direction length (W) of the second region (220b) b2 ) and the width direction length (W) of the first region (210b) b1 ) ratio (W b2 / W b1 ) may be greater than 1 and less than or equal to 20, greater than or equal to 2 and less than or equal to 18, or greater than or equal to 5 and less than or equal to 16. The ratio (W a2 / W a1 , W b2 / W b1 ) If the aforementioned range is satisfied, the capacity can be maximized while minimizing the size of the cathode (10).

[0160] In the second-1 metal layer (200a) according to one embodiment, the width direction length (W) of the first region (210a) a1 ) and the width direction length (W) of the 2nd-1 metal layer (200a) aT ) ratio (W a1 / W aT ) may be 0.01 to 0.1, 0.02 to 0.09, 0.03 to 0.08, or 0.04 to 0.07. In addition, in the second-second metal layer (200b), the width direction length (W) of the first region (210b) b1 ) and the width direction length (W) of the 2nd-2nd metal layer (200b) bT ) ratio (W b1 / W bT ) may be 0.01 to 0.1, 0.02 to 0.09, 0.03 to 0.08 or 0.04 to 0.07. The ratio (W a1 / W aT , W b1 / W bT ) satisfies the aforementioned range, sufficient bonding strength can be secured between the first metal layer (100) and the second-1 metal layer (200a) and between the first metal layer (100) and the second-2 metal layer (200b), respectively.

[0161] In a cathode (10) according to one embodiment, a first region (210a, 210b) (e.g., an overlapping region) that overlaps with at least one first metal layer (100) among a plurality of second metal layers (e.g., a 2-1 metal layer (200a) and a 2-2 metal layer (200b)) may be embedded in the first metal layer (100).

[0162] In the cathode (10) according to one embodiment, the first region (210a) of the 2-1 metal layer (200a) may be embedded in the first metal layer (100). For example, the upper surface of the 2-1 metal layer (200a) and the upper surface of the first metal layer (100) may be positioned on the same plane. That is, the 2-1 metal layer (200a) may not include an upper step between the 2-1 metal layer (200a) and the first metal layer (100) such that the first region (210a) is embedded in the first metal layer (100).

[0163] In the cathode (10) according to one embodiment, the first region (210b) of the 2-2 metal layer (200b) may be embedded in the first metal layer (100). The lower surface of the 2-2 metal layer (200b) and the lower surface of the first metal layer (100) may be positioned on substantially the same plane. For example, the 2-2 metal layer (200b) may not include a lower step between the 2-2 metal layer (200b) and the first metal layer (100) while the first region (210b) is embedded in the first metal layer (100).

[0164] Through the shape of the 2-1 metal layer (200a) and the 2-2 metal layer (200b) described above, there are cases where the 1st metal layer (100) and the 2-1 metal layer (200a) or the 2-2 metal layer (200b) are joined and then rewinded, and at this time, the problem of misalignment between the metal layers and the problem of the electrode being twisted due to the meandering can be prevented. In addition, through this shape, when unwinding is performed to manufacture the cathode structure (see 10A of FIG. 36) described later after rewinding as described above, the problem of meandering can be prevented. In addition, this form can prevent the problem of the stack portion (10A_S) of the cathode structure (see 10A of FIG. 36) protruding excessively when there is a step (especially, when it is thicker than the thickness of the anode (see 30 of FIG. 36) to be described later), thereby reducing the energy density per volume of the battery cell.

[0165] In a cathode (10) according to one embodiment, the first region (210a, 210b) (e.g., overlapping region) overlapping the first metal layer (100) of each of the plurality of second metal layers (e.g., the 2-1 metal layer (200a) and the 2-2 metal layer (200b)) has a width direction length (W) that is substantially the same as each other. a1 , W b1 ) can have.

[0166] In the cathode (10) according to one embodiment, the width direction length (W) of the first region (210a) of the second-first metal layer (200a) a1 ) and the width direction length (W) of the first region (210b) of the second-2 metal layer (200b) b1 ) may be substantially the same. Substantially the same means that the width direction length (W) of the first region (210a) of the second-first metal layer (200a) a1 ) and the width direction length (W) of the first region (210b) of the second-2 metal layer (200b) b1) may be the same or different, but may mean that R according to the following formula 1 is 10% or less. This form may be advantageous in manufacturing a cathode structure (see 10A of FIG. 36) including a folding portion and a stack portion to be described later.

[0167] [Formula 1]

[0168] R = |W a1 -W b1 | / W a1 X100

[0169] In Equation 1, W a1 is the width direction length of the first region (210a) of the above 2-1 metal layer (200a), and W b1 may refer to the width direction length of the first region (210b) of the above 2-2 metal layer (200b).

[0170] Referring to FIG. 12, in the cathode (10) according to one embodiment, the width direction length (W) of the second region (220a) of the second-1 metal layer (200a) a2 ) and the width direction length (W) of the second region (220b) of the second-2 metal layer (200b) b2 ) may be substantially the same. Substantially the same means that the width direction length (W) of the second region (220a) of the second-1 metal layer (200a) a2 ) and the width direction length (W) of the second region (220b) of the second-2 metal layer (200b) b2 ) may be the same or different, but it may mean that R' according to the following formula 2 is 10% or less.

[0171] [Formula 2]

[0172] R' = |W a2 -W b2 | / W a2 X100

[0173] In Equation 2, W a2 is the width direction length of the second region (220a) of the above 2-1 metal layer (200a), and W b2may refer to the width direction length of the second region (220b) of the above-mentioned 2-2 metal layer (200b).

[0174] Unlike Fig. 12, in another embodiment of the cathode (10), the width direction length (W) of the second region (220a) of the second-1 metal layer (200a) a2 ) and the width direction length (W) of the second region (220b) of the second-2 metal layer (200b) b2 ) may be different. For example, the width direction length (W) of the second region (220a) of the second-1 metal layer (200a) a2 ) is the width direction length (W) of the second region (220b) of the second-2 metal layer (200b). b2 ) may be larger than. Here, a negative electrode tab (see 230a of FIG. 22) to be described later may be formed on the 2-1 metal layer (200a) having a larger widthwise length, and a negative electrode tab to be described later may not be formed on the 2-2 metal layer (200b) having a smaller widthwise length. In one example, the widthwise length (W) of the second region (220b) of the 2-2 metal layer (200b) b2 ) is the width direction length (W) of the first region (210b) of the second-second metal layer (200b). b1 ) may be shorter than the first region (210b). For example, in this case, the second-second metal layer (200b) may only have the first region (210b).

[0175] In one example, the thickness of the first metal layer (100) may be greater than the thickness of one or more of the second metal layers (e.g., the 2-1 metal layer (200a) and the 2-2 metal layer (200b)). For example, the thickness of the first metal layer (100) may be greater than the sum of the thicknesses of the 2-1 metal layer (200a) and the 2-2 metal layer (200b). Through this, the tensile strength of the negative electrode (10) can be improved.

[0176] In a cathode (10) according to one embodiment, a cathode tab (a first cathode tab (230a of FIG. 22), a second cathode tab) may be formed in at least a portion of one or more second regions (220a, 220b) (e.g., non-overlapping regions) among a plurality of second metal layers (e.g., a 2-1 metal layer (200a) and a 2-2 metal layer (200b)). For example, a notching process may be performed on one or more second regions (220a, 220b) (e.g., non-overlapping regions) among the second metal layers (e.g., a 2-1 metal layer (200a) and a 2-2 metal layer (200b)), thereby forming a cathode tab (a first cathode tab (230a of FIG. 22), a second cathode tab). That is, the cathode (10) may include a cathode tab (first cathode tab (230a of FIG. 22), second cathode tab) formed in one or more second regions (220a, 220b) (e.g., non-overlapping regions) among the second metal layers (e.g., the 2-1 metal layer (200a) and the 2-2 metal layer (200b)).

[0177] In the cathode (10) according to one embodiment, the cathode tabs (the first cathode tab (230a of FIG. 22), the second cathode tab) may be formed independently in multiple numbers. Here, the notching process is not particularly limited, but may be performed by a contact method such as a puncher or a non-contact method using a laser, for example. The cathode (10) may include multiple cathode tabs (the first cathode tab (230a of FIG. 22), the second cathode tab) formed in each of one or more second regions (220a, 220b) (e.g., non-overlapping regions) among the second metal layers (e.g., the 2-1 metal layer (200a) and the 2-2 metal layer (200b)).

[0178] In various embodiments, the second metal layer (e.g., the 2-1 metal layer (200a) and the 2-2 metal layer (200b)) is formed of a metal having relatively lower reactivity than lithium metal, so that even if the notching process is performed in a non-contact manner, the occurrence of safety issues due to dust can be minimized.

[0179] FIG. 13 and FIG. 14 illustrate a part of the manufacturing process of the negative electrode sheet (see 10S of FIG. 22) according to the fourth embodiment of the present application, and the description thereof may refer to the description in FIG. 2 and FIG. 3 unless contradictory. Referring to FIG. 13, the 2-1 metal layer (200a) and the 2-2 metal layer (200b) may be positioned on the upper or lower side, respectively, with the first metal layer (100) interposed therebetween so as to overlap a part of one edge area of ​​the first metal layer (100). The 2-1 metal layer (200a) and the 2-2 metal layer (200b) may be transported in the same direction through a transport roll (not shown). In addition, the transport direction of the first metal layer (100) and the transport directions of the 2-1 metal layer (200a) and the 2-2 metal layer (200b) may be the same.

[0180] In one embodiment, referring to FIG. 14, the first metal layer (100) and the second-first metal layer (200a) and the first metal layer (100) and the second-second metal layer (200b) can be each rolled with a roller (R). Specifically, the overlapping areas of the first metal layer (100) and the second-first metal layer (200a) and the first metal layer (100) and the second-second metal layer (200b) can be mutually joined by applying pressure with the roller (R).

[0181] FIGS. 15 to 17 illustrate a part of a manufacturing process of a negative electrode sheet (see 10S of FIG. 22) according to a fifth embodiment of the present application. A roller (R) can roll a part of an edge area on one side of a first metal layer (100) that is transported in the +X-axis direction. A plurality of rollers (R) may be provided to roll both the upper and lower surfaces of the first metal layer (100). Referring to FIG. 16, the first metal layer (100) may have a first groove (H1) formed on the upper surface side and a second groove (H2) formed on the lower surface side by the roller (R). A 2-1 metal layer (200a) may be introduced into the first groove (H1), and a 2-2 metal layer (200b) may be introduced into the second groove (H2). Referring to FIG. 17, each of the 2-1 metal layer (200a) introduced into the 1st groove (H1) and the 2-2 metal layer (200b) introduced into the 2nd groove (H2) can be bonded to the 1st metal layer (100) through a bonding means such as a laser device (LA).

[0182] Fig. 18 illustrates a part of the manufacturing process of the negative electrode sheet (see 10S of Fig. 22) according to the sixth embodiment of the present application. Referring to Fig. 18, as in Figs. 15 and 16, after the roller (R) rolls a part of one edge area of ​​the first metal layer (100), a binder (B) can be applied onto the first groove (H1) and the second groove (H2) formed by rolling, respectively, and a second-first metal layer (200a) and a second-second metal layer (200b) can be introduced onto the binder (B) and bonded to the first metal layer (100).

[0183] FIGS. 19 and 20 illustrate a part of the manufacturing process of a negative electrode sheet (10S) according to one embodiment of the present application. FIG. 21 is a plan view of FIG. 20, illustrating a part of the manufacturing process of a negative electrode sheet (10S) according to one embodiment of the present application.

[0184] Referring to FIG. 19, the first metal layer (100) and the 2-1 metal layer (200a) can be bonded to each other in the manner described above to form a bonding boundary line (CL). The bonding boundary line (CL) can mean an end line of the first metal layer (100) among the areas where the first metal layer (100) and the 2-1 metal layer (200a) overlap. The 2-2 metal layer (200b) can also be bonded to the first metal layer (100) like the 2-1 metal layer (200a) to form a bonding boundary line (CL). For example, the bonding boundary line (CL) may mean the end line of the first metal layer (100) among the areas where the first metal layer (100) and the 2-1 metal layer (200a) overlap with each other based on the thickness direction of the first metal layer (100) (e.g., the +Z-axis direction of FIG. 19), and the same may be true for the 2-2 metal layer (200b).

[0185] Referring to FIGS. 20 and 21, a notching process can be performed on a cathode sheet (10S) according to one embodiment using a laser device (LA).

[0186] For example, a laser (L) generated from a laser device (LA) may be irradiated to a second region (220a) of a 2-1 metal layer (200a), whereby the second region (220a) may be partially cut to form a first cathode tab (see 230a in FIG. 22). The 2-2 metal layer (200b) may also be similar to the 2-1 metal layer (200a).

[0187] Fig. 22 is a plan view illustrating at least a portion of a negative electrode sheet (10S) according to one embodiment of the present application. Fig. 23 is a plan view illustrating a state in which a negative electrode sheet (see 10S of Fig. 22) is cut to form a negative electrode (10) according to one embodiment of the present application.

[0188] According to one embodiment, a negative electrode sheet (10S) may have a first negative electrode tab (230a) formed in a second region (220a) of a 2-1 metal layer (200a), which includes a first tab (231a), a second tab (232a), and a third tab (233a). That is, the negative electrode sheet (10S) may include a first negative electrode tab (230a) formed in the second region (220a) of the 2-1 metal layer (200a).

[0189] For example, in the 2-1 metal layer (200a), the second tab (232a) and the third tab (233a), which are adjacent to each other on both sides of the first tab (231a), may be positioned spaced apart from the first tab (231a) by a predetermined distance. For example, the distance between the first tab (231a) and the second tab (232a) may be the 1a length (W). a12 ) is the second a length (W) which is the gap between the first tab (231a) and the third tab (233a). a13 ) can be formed longer than that.

[0190] Although not shown separately in FIG. 22, the 2-2 metal layer (200b) may have a second negative electrode tab formed in the second region (220b) of the 2-2 metal layer (200b), similar to the 2-1 metal layer (200a), including a first tab, a second tab, and a third tab. That is, the negative electrode sheet (10S) according to the embodiment may include a second negative electrode tab formed in the second region (220b of FIG. 20) of the 2-2 metal layer (200b).

[0191] For example, in the 2-2 metal layer (200b), the second tab and the third tab, which are adjacent to each other on both sides of the first tab, may be positioned spaced apart from the first tab by a predetermined distance. For example, the distance 1b between the first and second tabs may be formed to be longer than the distance 2b between the first cap and the third tab. By making the distance between the tabs different in this way, it may be advantageous to align the tabs.

[0192] According to one embodiment, a cathode sheet (10S) may include a cathode tab (a first cathode tab (230a), a second cathode tab) formed in at least one second region (220a, 220b of FIG. 20) among a plurality of second metal layers (a second-first metal layer (200a), a second-second metal layer (200b)).

[0193] Although not particularly limited, the first cathode tab of the 2-1 metal layer (200a) and the second cathode tab of the 2-2 metal layer (200b) may be bonded at least in some areas at positions corresponding to each other. For example, the first tab (231a) of the 2-1 metal layer (200a) may be bonded to the first tab of the 2-2 metal layer (200b) at least in some areas. This simplifies the tab structure, thereby improving manufacturing convenience.

[0194] According to one embodiment, a cathode sheet (10S) may include a margin region (first margin region (235a), second margin region) provided adjacent to the first metal layer (100) in at least one second region (220a, 220b of FIG. 20) among a plurality of second metal layers (2-1 metal layer (200a), 2-2 metal layer (200b)).

[0195] Specifically, the negative electrode sheet (10S) according to one embodiment may further include a first margin region (235a) which is a region other than the region corresponding to the first negative electrode tab (230a) in the second region (220a) of the 2-1 metal layer (200a). Referring to FIG. 22, at least a portion of the first margin region (235a) may be provided between the first negative electrode tab (230a) and the first metal layer (100). When viewed in the thickness direction of the first metal layer (100) (i.e., the +Z-axis direction), at least a portion of the first margin region (235a) may be provided between the first negative electrode tab (230a) and the first metal layer (100). Also, referring to FIG. 22, at least a portion of the first margin region (235a) may be provided between the first cathode tab (230a) and the first region (210) of the second-first metal layer (200a).

[0196] For example, when viewed in the thickness direction of the first metal layer (100) (i.e., +Z-axis direction), at least a portion of the first margin region (235a) may be provided between the first cathode tab (230a) and the first region (210a) of the 2-1 metal layer (200a). That is, referring to FIG. 22, the first region (210a) of the 2-1 metal layer (200a) may be provided between the first margin region (235a) and the first metal layer (100). When viewed in the thickness direction of the first metal layer (100) (i.e., +Z-axis direction), the first region (210a) of the 2-1 metal layer (200a) may be provided between the first margin region (235a) and the first metal layer (100). Through this, when the manufacturing process of the negative electrode sheet (10S) is performed in a roll-to-roll manner, the stretching of the first metal layer (100), which is lithium metal, in the machine direction (MD) is suppressed, so that an advantageous effect can be obtained during the continuous notching process.

[0197] The description regarding the 2-1 metal layer (200a) above may also be the same for the 2-2 metal layer (200b). Specifically, in the description regarding the 2-1 metal layer (200a), the 2-1 metal layer (200a) may be the 2-2 metal layer (200b), the first negative electrode tab (230a) may be the second negative electrode tab, and the first margin region (235a) may be the second margin region. In the negative electrode sheet (10S) according to one embodiment, each of the second region (220a) of the 2-1 metal layer (200a) and the second region (220b of FIG. 20) of the 2-2 metal layer (200b) may include a margin region (e.g., 235a) provided adjacent to the 1 metal layer (100). Here, the margin region (e.g., 235a) may be a region other than the region where the negative electrode tab (e.g., the first negative electrode tab (230a), the second negative electrode tab) is formed by the notching process in each of the second region (220a) of the 2-1 metal layer (200a) and the second region (220b of FIG. 20) of the 2-2 metal layer (200b). In addition, as described above, a plurality of negative electrode sheets (10S) can be laminated in one direction (e.g., the thickness direction of the first metal layer (100) (i.e., the +Z-axis direction)) or in a curved state (folded) by performing a notching process at once to form negative electrode tabs (e.g., the first negative electrode tab (230a), the second negative electrode tab), thereby simplifying the process and minimizing the tab alignment mismatch phenomenon that occurs when negative electrode tabs (e.g., the first negative electrode tab (230a), the second negative electrode tab) are formed in advance.

[0198] According to one embodiment, a negative electrode sheet (10S) may be cut according to a predetermined rule using a cutter (not shown). The predetermined rule is not limited, but may be, for example, for standardizing the negative electrode (10) to be formed, and reference may be made to FIG. 23. The cutter may apply, for example, one or more of a blade contact cutting method and a laser non-contact cutting method, but is not limited thereto. Referring to FIG. 23, the negative electrode sheet (10S) may be cut along a vertical direction (TD) (e.g., +Y-axis direction), thereby forming individual negative electrodes (10).

[0199] According to one embodiment, the negative electrode (10) may include a negative electrode tab (a first negative electrode tab (230a), a second negative electrode tab) formed in at least one second region (220a, 220b of FIG. 20) among a plurality of second metal layers (a second-first metal layer (200a), a second-second metal layer (200b)). In addition, the negative electrode (10) according to one embodiment may include a margin region (a first margin region (235a), a second margin region) provided adjacent to the first metal layer (100) in at least one second region (220a, 220b of FIG. 20) among a plurality of second metal layers (a second-first metal layer (200a), a second-second metal layer (200b)).

[0200] According to one embodiment, the cathode (10) may include a margin region (first margin region (235a), second margin region) other than the cathode tab (first cathode tab (230a), second cathode tab) in at least one second region (220a, 220b of FIG. 20) among a plurality of second metal layers (second-first metal layer (200a), second-second metal layer (200b)).

[0201] Specifically, the negative electrode (10) according to one embodiment may include a first margin region (235a) which is a region other than the first negative electrode tab (230a) in the second region (220a) of the 2-1 metal layer (200a). Referring to FIG. 23, at least a portion of the first margin region (235a) may be provided between the first negative electrode tab (230a) and the first metal layer (100). When viewed in the thickness direction of the first metal layer (100) (i.e., the +Z-axis direction), at least a portion of the first margin region (235a) may be provided between the first negative electrode tab (230a) and the first metal layer (100). In addition, referring to FIG. 23, at least a portion of the first margin region (235a) may be provided between the first negative electrode tab (230a) and the first region (210) of the 2-1 metal layer (200a). When viewed in the thickness direction of the first metal layer (100) (i.e., +Z-axis direction), at least a portion of the first margin region (235a) may be provided between the first cathode tab (230a) and the first region (210a) of the 2-1 metal layer (200a). That is, referring to FIG. 23, the first region (210a) of the 2-1 metal layer (200a) may be provided between the first margin region (235a) and the first metal layer (100). When viewed in the thickness direction of the first metal layer (100) (i.e., +Z-axis direction), the first region (210a) of the 2-1 metal layer (200a) may be provided between the first margin region (235a) and the first metal layer (100). Through this, the first metal layer (100), which is lithium metal, can be protected during the notching process to improve process stability and the tensile strength of the negative electrode (10) can be improved.

[0202] The description regarding the 2-1 metal layer (200a) above may also apply to the 2-2 metal layer (200b). Specifically, in the description regarding the 2-1 metal layer (200a), the 2-1 metal layer (200a) may be the 2-2 metal layer (200b), the first negative electrode tab (230a) may be the second negative electrode tab, and the first margin region (235a) may be the second margin region.

[0203] In addition, through the margin region (the first margin region (235a), the second margin region), it is possible to prevent a short circuit from occurring due to lithium dendrites directly contacting the positive electrode tab connected to the positive electrode (see 30 in Fig. 36). In particular, it is possible to effectively prevent a short circuit from occurring even in a unidirectional battery in which the positive electrode tab and the negative electrode tab (the first negative electrode tab (230a), the second negative electrode tab) face the same direction.

[0204] Meanwhile, cutting the negative electrode sheet (10S) so that two tabs (230) are included in one negative electrode (10) as shown in FIG. 23 is merely exemplary, and according to another embodiment, the negative electrode sheet (10S) may be formed with cutting points in units of three or more tabs (e.g., ten tabs) to facilitate the formation of a negative electrode structure (10A) as shown in FIG. 36 described below.

[0205] For example, the negative electrode sheet (10S) may be cut into predetermined units after interposing an anode (e.g., the positive electrode (30) of FIG. 36) between two surfaces formed by forming a bend. As another example, the negative electrode sheet (10S) may be pre-cut at a stage prior to interposing the positive electrode.

[0206] FIG. 24 is a plan view illustrating at least a portion of a cathode (10) according to one embodiment of the present application.

[0207] According to one embodiment, a cathode (10) may include a plurality of first metal layers (e.g., a first-first metal layer (100a) and a first-second metal layer (100b)). In addition, in the cathode (10), a second metal layer (200) may be interposed between a plurality of first metal layers (e.g., a first-first metal layer (100a) and a first-second metal layer (100b)).

[0208] For example, a cathode (10) according to an example may include a first metal layer (100) including a 1-1 metal layer (100a) and a 1-2 metal layer (100b), and a second metal layer (200). For example, the second metal layer (200) may be formed by overlapping and bonding with a portion of each of the 1-1 metal layer (100a) and the 1-2 metal layer (100b). The second metal layer (200) may protrude in one direction from one edge of each of the 1-1 metal layer (100a) and the 1-2 metal layer (200b). In addition, for example, in the cathode (10), the second metal layer (200) may be formed by overlapping and bonding with a portion of one edge of each of the 1-1 metal layer (100a) and the 1-2 metal layer (100b).

[0209] In a cathode (10) according to one embodiment, a second metal layer (200) may be interposed between the first-first metal layer (100a) and the first-second metal layer (100b).

[0210] In the cathode (10) according to one embodiment, the second metal layer (200) may be formed by overlapping with a portion of the first-first metal layer (100a) and the first-second metal layer (100b) to form a bond. For example, the second metal layer (200) may protrude in one direction from one edge of each of a plurality of first metal layers (e.g., the first-first metal layer (100a) and the first-second metal layer (100b)).

[0211] According to various embodiments, each of the plurality of first metal layers (e.g., the first-first metal layer (100a) and the first-second metal layer (100b)) may refer to the contents of the first metal layer (100) described above, as long as they are not contradictory.

[0212] According to an example, various advantages can be obtained by interposing a second metal layer (200) between a plurality of first metal layers (e.g., the first-first metal layer (100a) and the first-second metal layer (100b)) in the negative electrode (10). For example, when the positive electrode faces both sides of the negative electrode (10), the positive electrode can sufficiently utilize the area of ​​the first metal layer (e.g., the first-first metal layer (100a) and the first-second metal layer (100b)), and the overall length of the battery cell can be reduced, thereby improving the energy density per weight and the energy density per volume. In addition, by minimizing the position of the negative electrode tab (see 230 of FIG. 34) from being tilted to one side, easy processing or design can be possible. In addition, the tensile strength of the negative electrode (10) can be improved.

[0213] For example, a plurality of first metal layers (e.g., the first-first metal layer (100a) and the first-second metal layer (100b)) may be formed of lithium metal (Li metal).

[0214] According to various embodiments, the second metal layer (200) may be formed of a material other than lithium metal. For example, the second metal layer (200) may be formed of another metal having lower reactivity than lithium (Li) metal. In addition, for example, the second metal layer (200) may be formed of at least one material selected from the group consisting of copper (Cu), nickel (Ni), and stainless steel.

[0215] In one embodiment, the second metal layer (200) may have various structures. Each of the second metal layers (200) may include one or more of a predetermined pattern structure and a surface-treated region. One or more of the predetermined pattern structure and the surface-treated region may be included in at least a portion of the first region (210).

[0216] For example, at least a portion of the second metal layer (200) (e.g., at least a portion of the area in contact with the first metal layer (the 1-1 metal layer (100a) or the 1-2 metal layer (100b))) may include a predetermined pattern structure. The pattern structure may be, for example, a mesh structure or a structure in which a grid pattern is formed on the surface, or may have both of these structures. For example, a mesh structure may mean a structure in which a plurality of holes are formed, and a grid pattern may mean a structure in which a plurality of grooves are formed. Through this, the contact area between the first metal layer (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)) and the second metal layer (200) may be maximized, thereby improving the bonding strength.

[0217] Additionally, at least a portion of the second metal layer (200) (e.g., at least a portion of the portion of the second metal layer (200) that contacts the first metal layer (the first-first metal layer (100a) or the first-second metal layer (100b))) may be surface-treated. The surface treatment may be performed, for example, by plasma treatment. When surface-treated, the surface may have a different surface roughness from other regions. Through such an appropriate surface treatment, the bonding strength between the first metal layer (100) and the second metal layer (200) may be improved.

[0218] In one example, the thickness of the first metal layer (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)) may be greater than the thickness of the second metal layer (200). In addition, for example, the thicknesses of each of the 1-1 metal layer (100a) and the 1-2 metal layer (100b) may be greater than the thickness of the second metal layer (200). Through this, the tensile strength of the negative electrode (10) can be improved.

[0219] In a cathode (10) according to one embodiment, the second metal layer (200) may include a first region (210) (e.g., an overlapping region) that overlaps with a plurality of first metal layers (e.g., a first-first metal layer (100a) or a first-second metal layer (100b)) and a second region (220) (e.g., a non-overlapping region) that is a region other than the first region (210). For example, based on the thickness direction (e.g., +Z-axis direction of FIG. 24) of the first metal layer (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)), the second metal layer (200) may include a first region (210) (e.g., overlapping region) that overlaps with a plurality of first metal layers (e.g., the 1-1 metal layer (100a) or the 1-2 metal layer (100b)) and a second region (220) (e.g., non-overlapping region) that is a region other than the first region (210).

[0220] In one embodiment, if there are multiple first metal layers (100), the second metal layer (200) may have a first region (210) and a second region (220) determined based on each first metal layer (100). For example, the first region (210) (e.g., overlapping region) where the second metal layer (200) overlaps the 1-1 metal layer (100a) and the first region (210) (e.g., overlapping region) where the second metal layer (200) overlaps the 1-2 metal layer (100b) may be the same. However, in the drawing, the first region (210) (e.g., overlapping region) where the second metal layer (200) overlaps the first-first metal layer (100a) and the first region (210) (e.g., overlapping region) where the second metal layer (200) overlaps the first-second metal layer (100b) are shown as being the same, but this is not limited thereto and they may be different.

[0221] Meanwhile, when the cathode (10) according to one embodiment includes a plurality of first metal layers (100), the relationship between the second metal layer (200) and the first region (210) (e.g., overlapping region) and the second region (220) (e.g., non-overlapping region) of each first metal layer (100) can independently satisfy the above-described content.

[0222] In one embodiment, at least one of the second metal layer (200) and the plurality of first metal layers (e.g., the first-first metal layer (100a) and the first-second metal layer (100b)) may be formed such that a widthwise length (W1) of a first region (e.g., an overlapping region) that overlaps with each other is shorter than a widthwise length (W2) of a second region (e.g., a non-overlapping region) that is an area other than the first region (e.g., an overlapping region).

[0223] For example, in each of the second metal layer (200) and the 1-1 metal layer (100a) and the second metal layer (200) and the 1-2 metal layer (100b), the width direction length (W1) of the first region (210) may be shorter than the width direction length (W2) of the second region (220), and the ratio (W2 / W1) of the width direction length (W2) of the second region (220) and the width direction length (W1) of the first region (210) may also satisfy the aforementioned range. In addition, in each of the second metal layer (200) and the 1-1 metal layer (100a) and the second metal layer (200) and the 1-2 metal layer (100b), the width direction length (W1) of the first region (210) or the aforementioned ratio (W2 / W1) may independently satisfy the aforementioned condition.

[0224] In a cathode (10) according to one embodiment, a first region (210) (e.g., a central region) of a second metal layer (200) may be embedded in at least one of a plurality of first metal layers (100a, 100b).

[0225] In the cathode (10) according to one embodiment, the first region (210) of the second metal layer (200) may be embedded in the 1-1 metal layer (100a) and the 1-2 metal layer (100b). For example, the first region (210) of the second metal layer (200) may be embedded while being covered by the 1-1 metal layer (100a) and the 1-2 metal layer (100b).

[0226] Meanwhile, in the cathode (10) according to one embodiment, the plurality of first metal layers (100a, 100b) may be bonded at least partially in a region other than the region where the first region (210) (e.g., overlapping region) of the second metal layer (200) is buried. For example, the plurality of first metal layers (100a, 100b) may be bonded at least partially in a position corresponding to the second region (220) (e.g., non-overlapping region) of the second metal layer (200).

[0227] In the cathode (10) according to one embodiment, the first-first metal layer (100a) and the first-second metal layer (100b) may be bonded at least partially outside of the area where the first region (210) of the second metal layer (200) is buried. For example, the first-first metal layer (100a) and the first-second metal layer (100b) may be bonded at least partially at a position corresponding to the second region (220) (e.g., non-overlapping area) of the second metal layer (200). That is, the first-first metal layer (100a) and the first-second metal layer (100b) may be in contact with each other and be bonded in an area (i.e., the second region (220) (e.g., non-overlapping area)) that does not correspond to the first region (210) of the second metal layer (200).

[0228] In the cathode (10) according to one embodiment, a cathode tab (see 230 of FIG. 34) may be formed in at least a portion of a second region (220) (e.g., a non-overlapping region) of the second metal layer (200). For example, the cathode tab (see 230 of FIG. 34) may be formed by performing a notching process on the second region (220) of the second metal layer (200). That is, the cathode (10) may include a cathode tab (see 230 of FIG. 34) formed in the second region (220) of the second metal layer (200).

[0229] In one embodiment, the cathode (10) may be formed with a plurality of cathode tabs (see 230 in FIG. 34). Here, the notching process is not particularly limited, but may be performed by a contact method such as a puncher or a non-contact method using a laser. The cathode (10) may include a plurality of cathode tabs (230 in FIG. 34) formed in the second region (220) of the second metal layer (200).

[0230] In various embodiments, the second metal layer (200) is formed of a metal having relatively low reactivity compared to lithium metal, so that even if the notching process is performed in a non-contact manner, the occurrence of safety issues due to dust can be minimized.

[0231] FIG. 25 and FIG. 26 illustrate a part of a manufacturing process of a negative electrode sheet (see 10S of FIG. 34) according to the seventh embodiment of the present application, and the description thereof may refer to the description in FIG. 13 and FIG. 14 unless contradictory. Referring to FIG. 25, the second metal layer (200) may overlap a part of an edge region on one side of each of the 1-1 metal layer (100a) and the 1-2 metal layer (100b). In addition, the 1-1 metal layer (100a) and the 1-2 metal layer (100b) may be positioned on the upper or lower side of the second metal layer (200), respectively, while the second metal layer (200) is positioned between the 1-1 metal layer (100a) and the 1-2 metal layer (100b). The 1-1 metal layer (100a) and the 1-2 metal layer (100b) can be transported in the same direction through a transport roll (not shown).

[0232] For example, the transport direction of the second metal layer (200) and the transport directions of the 1-1 metal layer (100a) and the 1-2 metal layer (100b) may be the same. Meanwhile, as will be described later, when the second metal layer (200) is introduced into the 1-1 metal layer (100a) and the 1-2 metal layer (100b), the 1-1 metal layer (100a) and the 1-2 metal layer (100b) may come into contact with each other and become a laminated state.

[0233] In one embodiment, referring to FIG. 26, the first-first metal layer (100a) and the second metal layer (200) and the first-second metal layer (100b) and the second metal layer (200) can each be rolled with a roller (R). Specifically, the overlapping areas of the first-first metal layer (100a) and the second metal layer (200) and the first-second metal layer (100b) and the second metal layer (200) can be mutually joined by applying pressure with the roller (R).

[0234] Figures 27 to 29 illustrate a part of the manufacturing process of the negative electrode sheet (see 10S of Figure 34) according to the eighth embodiment of the present application. The roller (R) can roll a part of one edge area of ​​each of the first-first metal layer (100a) and the first-second metal layer (100b) that are transported in the +X direction. A plurality of rollers (R) are provided to roll the lower surface of the first-first metal layer (100a) and the upper surface of the first-second metal layer (100b), respectively. Referring to Figure 28, the first-first metal layer (100a) has an A groove (H) formed on the lower surface by the roller (R). A ) can be formed, and the first-second metal layer (100b) is formed on the upper surface side by a roller (R) in the B groove (H B ) can be formed. Home A (H A ) and B Home (H B ) may be introduced into each of the second metal layers (200). Referring to Fig. 29, the A groove (H A ) and B Home (H B ) can be bonded to the first-first metal layer (100a) and the first-second metal layer (100b) through a bonding means such as a laser device (LA).

[0235] Fig. 30 illustrates a part of the manufacturing process of the negative electrode sheet (see 10S of Fig. 34) according to the ninth embodiment of the present application. Referring to Fig. 30, as in Figs. 27 and 28, the roller (R) rolls a part of one edge area of ​​each of the first-first metal layer (100a) and the first-second metal layer (100b), and then the A groove (H) is formed by rolling. A ) and B Home (H B ) can be applied to each of the binders (B), and a second metal layer (200) can be introduced onto each of the binders (B) to bond with the first-first metal layer (100a) and the first-second metal layer (100b).

[0236] FIG. 31 and FIG. 32 illustrate a part of the manufacturing process of a negative electrode sheet (10S) according to one embodiment of the present application. FIG. 33 is a plan view of FIG. 32, illustrating a part of the manufacturing process of a negative electrode sheet (10S) according to one embodiment of the present application.

[0237] Referring to FIG. 31, the 1-1 metal layer (100a) and the 2nd metal layer (200) may be bonded to each other in the manner described above to form a bonding boundary line (CL). The bonding boundary line (CL) may refer to an end line of the 2nd metal layer (200) in an area where the 1-1 metal layer (100a) and the 2nd metal layer (200) overlap. For example, the bonding boundary line (CL) may refer to an end line of the 1-1 metal layer (100a) in an area where the 1-1 metal layer (100a) and the 2nd metal layer (200) overlap, based on the thickness direction (e.g., the +Z-axis direction in FIG. 31) of one of the 1st metal layers (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)). The 1-2 metal layer (100b) may also be similar to the 1-1 metal layer (100a).

[0238] Referring to FIGS. 32 and 33, a notching process can be performed on a cathode sheet (10S) according to one embodiment using a laser device (LA).

[0239] For example, a laser (L) generated from a laser device (LA) can be irradiated to a second region (220) of a second metal layer (200), whereby the second region (220) can be partially cut to form a cathode tab (see 230 in FIG. 34).

[0240] Fig. 34 is a plan view illustrating at least a portion of a negative electrode sheet (10S) according to one embodiment of the present application. Fig. 35 is a plan view exemplarily illustrating a process of forming a negative electrode by cutting a negative electrode sheet (see 10S of Fig. 34) according to one embodiment of the present application.

[0241] According to one embodiment, a negative electrode sheet (10S) may have a negative electrode tab (230) formed in a second region (220) of a second metal layer (200). Specifically, a negative electrode tab (230) including a first tab (231), a second tab (232), and a third tab (233) may be formed in the second region (220) of the second metal layer (200). That is, the negative electrode sheet (10S) according to one embodiment may include a negative electrode tab (230) formed in the second region (220).

[0242] For example, in the second metal layer (200), the second tab (232) and the third tab (233), which are adjacent to each other on both sides of the first tab (231), may be positioned spaced apart from the first tab (231) by a predetermined distance. For example, the first length (W), which is the distance between the first tab (231) and the second tab (232), may be 12 ) is the second length (W) which is the gap between the first tab (231) and the third tab (233). 13 ) can be formed longer than the tabs. By making the distance between tabs different like this, it can be advantageous to align the tabs.

[0243] According to one embodiment, the negative electrode sheet (10S) may further include a margin region (235) which is a region other than the region corresponding to the negative electrode tab (230) in the second region (220). Referring to FIG. 34, at least a portion of the margin region (235) may be provided between the negative electrode tab (230) and the first metal layer (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)). When viewed in the thickness direction (i.e., the +Z-axis direction) of one of the first metal layers (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)), at least a portion of the margin region (235) may be provided between the negative electrode tab (230) and the first metal layer (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)). Additionally, referring to FIGS. 32 and 34, at least a portion of the margin region (235) may be provided between the cathode tab (230) and the first region (210).

[0244] For example, when viewed in the thickness direction (i.e., +Z-axis direction) of one of the first metal layers (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)), at least a portion of the margin region (235) may be provided between the cathode tab (230) and the first region (210). That is, referring to FIG. 34, the first region (210) may be provided between the margin region (235) and one of the first metal layers (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)). When viewed in the thickness direction (i.e., +Z-axis direction) of one of the first metal layers (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)), the first region (210) can be provided between the margin region (235) and one of the first metal layers (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)). Through this, when the manufacturing process of the negative electrode sheet (10S) is performed in a roll-to-roll manner, elongation of the first metal layer (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)), which is a lithium metal, in the machine direction (MD) is suppressed, so that an advantageous effect can be obtained during a continuous notching process.

[0245] Although Fig. 34 only illustrates the 1-1 metal layer (100a), it will be apparent to those skilled in the art that the 1-2 metal layer (100b) may also be similar to the 1-1 metal layer (100a).

[0246] According to one embodiment, a negative electrode sheet (10S) may include a margin region (235) provided adjacent to at least one of the first metal layers (the first-first metal layer (100a) or the first-second metal layer (100b)) in the second region (220). Here, the margin region (235) may be a region other than a region in which a negative electrode tab (230) is formed by a notching process in the second region (220). A plurality of negative electrode sheets (10S) can be laminated in one direction (for example, in the thickness direction (i.e., +Z-axis direction) of one of the first metal layers (1-1 metal layer (100a) or 1-2 metal layer (100b))) or in a curved state (folded) to perform a notching process at once to form a negative electrode tab (230), thereby simplifying the process and minimizing a tab alignment mismatch phenomenon that occurs when the negative electrode tab (230) is formed in advance.

[0247] According to one embodiment, a negative electrode sheet (10S) may be cut according to a predetermined rule using a cutter (not shown). The predetermined rule is not limited, but may be, for example, for standardizing the negative electrode (10) to be formed, and reference may be made to FIG. 35 . The cutter may employ, for example, one or more of a blade contact cutting method and a laser non-contact cutting method, but is not limited thereto. Referring to FIG. 35 , the negative electrode sheet (10S) may be cut along a vertical direction (TD) (e.g., +Y-axis direction), thereby forming individual negative electrodes (10).

[0248] According to one embodiment, the cathode (10) may include a cathode tab (230) formed in the second region (220). In addition, the cathode (10) according to one embodiment may include a margin region (235) provided adjacent to at least one of a plurality of first metal layers (the first-first metal layer (100a) or the first-second metal layer (100b)) in the second region (220).

[0249] According to one embodiment, the negative electrode (10) may include a margin region (235) in the second region (220) other than the negative electrode tab (230). Referring to FIG. 35, at least a portion of the margin region (235) may be provided between the negative electrode tab (230) and one of the first metal layers (the first-first metal layer (100a) or the first-second metal layer (100b)). When viewed in the thickness direction (i.e., the +Z-axis direction) of one of the first metal layers (the first-first metal layer (100a) or the first-second metal layer (100b)), at least a portion of the margin region (235) may be provided between the negative electrode tab (230) and one of the first metal layers (the first-first metal layer (100a) or the first-second metal layer (100b)). Also, referring to FIG. 35, at least a portion of the margin region (235) may be provided between the negative tab (230) and the first region (210). When viewed in the thickness direction (i.e., +Z-axis direction) of one of the first metal layers (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)), at least a portion of the margin region (235) may be provided between the negative tab (230) and the first region (210). That is, referring to FIG. 35, the first region (210) may be provided between the margin region (235) and one of the first metal layers (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)). When viewed in the thickness direction (i.e., +Z-axis direction) of one of the first metal layers (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)), the first region (210) can be provided between the margin region (235) and one of the first metal layers (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)). Through this, the first metal layer (the 1-1 metal layer (100a) or the 1-2 metal layer (100b)), which is lithium metal, can be protected during the notching process, thereby improving process stability and improving the tensile strength of the negative electrode (10).

[0250] In addition, through the margin region (235), it is possible to prevent a short circuit from occurring due to lithium dendrites directly contacting the positive electrode tab connected to the positive electrode (see 30 in FIG. 36). In particular, it is possible to effectively prevent a short circuit from occurring even in a unidirectional battery in which the positive electrode tab and the negative electrode tab (230) face the same direction.

[0251] Although Fig. 35 only illustrates the 1-1 metal layer (100a), it will be apparent to those skilled in the art that the 1-2 metal layer (100b) may also be similar to the 1-1 metal layer (100a).

[0252] Meanwhile, cutting the negative electrode sheet (10S) so that two tabs (230) are included in one negative electrode (10) as shown in FIG. 35 is merely exemplary, and according to another embodiment, the negative electrode sheet (10S) may be formed with cutting points in units of three or more tabs (e.g., ten tabs) to facilitate the formation of a negative electrode structure (10A) as shown in FIG. 36 described below.

[0253] For example, the negative electrode sheet (10S) may be cut into predetermined units after forming an electrode assembly (e.g., electrode assembly (1) of FIG. 36) by interposing an anode (e.g., anode (30) of FIG. 36) between two surfaces formed by forming a bend. Alternatively, as another example, the negative electrode sheet (10S) may be cut in advance at a stage before interposing an anode.

[0254] FIG. 36 is a plan view illustrating at least a portion of an electrode assembly (1) according to one embodiment of the present application.

[0255] In various embodiments, the electrode assembly (1) may include a cathode structure (10A) including an anode (30), a cathode sheet (10S), and a separator (21, 22).

[0256] In one embodiment, the cathode structure (10A) may have a structure in which a cathode sheet (10S) is interposed between two separators (21, 22).

[0257] In one embodiment, the cathode structure (10A) may have a structure in which a cathode (10) cut from a cathode sheet (10S) is sandwiched between two separators (21, 22) instead of a cathode sheet (10S).

[0258] According to one embodiment, a positive electrode (30) may include a positive electrode active material layer and a positive electrode current collector supporting the positive electrode active material layer. For example, the positive electrode (30) may include a structure in which a positive electrode active material layer is formed on at least one side or both sides of a positive electrode current collector. The positive electrode active material layer includes a positive electrode active material, and may further include a positive electrode binder, a conductive material, and additives, as needed.

[0259] According to one embodiment, the positive electrode current collector is not particularly limited as long as it supports the positive electrode active material layer and has conductivity without causing physical and chemical changes to the composition included in the electrode assembly (1) and the battery cell, etc. For example, the positive electrode current collector may be made of copper or stainless steel surface-treated with aluminum, stainless steel, nickel, titanium, copper, palladium, calcined carbon, carbon, nickel, silver, or an aluminum-cadmium alloy. In addition, the positive electrode current collector may have fine unevenness formed on the surface, and the shape thereof may be various, such as a film, a sheet, a foil, a mesh, a net, or a foam.

[0260] According to one embodiment, a positive electrode active material may include a compound capable of reversibly intercalating and deintercalating lithium ions, sodium ions, or potassium ions. For example, a lithium, sodium, or potassium compound used as a positive electrode active material may have a layered structure, a crystal structure, or a combination thereof. In addition, in the present specification, a lithium compound may be a concept encompassing all compounds in which auxiliary elements, coating elements, and doping elements are introduced or substituted around a main active element. The main active element may include, for example, one or more selected from the group consisting of nickel (Ni), cobalt (Co), manganese (Mn), and aluminum (Al). The auxiliary elements, coating elements, and doping elements are elements that can improve the structural and chemical stability of the positive electrode active material by combining with the main active element, and may be distinguished depending on the method of combining with the main active element. Here, combining with the main active element may include not only chemically bonding with the main active element, but also existing on the surface of the positive electrode active material or penetrating from the surface. In addition, for example, the auxiliary element, coating element, and doping element may each independently include one or more selected from the group consisting of elements of Group 1, Group 2, Group 13, Group 14, Group 15, Group 16, and transition metals, excluding lithium in the periodic table.Specifically, for example, the auxiliary elements, coating elements and doping elements may each independently include one or more selected from the group consisting of sodium (Na), magnesium (Mg), calcium (Ca), yttrium (Y), titanium (Ti), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), iron (Fe), copper (Cu), silver (Ag), zinc (Zn), boron (B), gallium (Ga), carbon (C), silicon (Si), tin (Sn), strontium (Sr), barium (Ba), radium (Ra), phosphorus (P) and zirconium (Zr). For example, the cathode active material may include at least one selected from the group consisting of nickel-cobalt-manganese oxide (NCM), nickel-cobalt-aluminum oxide (NCA), nickel-cobalt-manganese-aluminum oxide (NCMA), cobalt oxide (LCO), manganese oxide (LMO), and iron phosphate (LFP) combined with lithium, sodium, or potassium.

[0261] According to one embodiment, the cathode active material may include a sulfur compound. The sulfur compound may be an inorganic sulfur (elemental sulfur, S8), an organic sulfur compound Li2S. x (x is 1 or more and 8 or less) and carbon-sulfur polymer ((C2S y ) n , y=2.5 to 50, n=1 to 1,000, 1 to 100, or 1 to 50. When the positive electrode active material includes a sulfur compound, the electrode assembly (1) can be applied to a lithium-sulfur (Li-S) battery.

[0262] According to one embodiment, the positive electrode binder may include a compound that can improve the internal bonding strength of the positive electrode active material layer and improve the adhesion strength of the positive electrode active material layer to the positive electrode current collector. The cathode binder may be, for example, polyvinylidene fluoride (PVDF), polyvinyl alcohol, styrene butadiene rubber (SBR), polyethylene oxide, carboxyl methyl cellulose (CMC), cellulose acetate, cellulose acetate butylate, cellulose acetate propionate, cyanoethylpullulan, cyanoethyl polyvinylalcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, polymethylmethacrylate, polybutylacrylate, It may include at least one selected from the group consisting of polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, and polyarylate.

[0263] According to one embodiment, a conductive material may include a compound that can improve the conductivity and ion or electron mobility of a positive electrode active material layer. The conductive material may include, for example, a carbon-based conductive material such as graphite, carbon black, acetylene black, Ketjen black, graphene, carbon nanotubes (CNTs), vapor-grown carbon fibers (VGCFs), and carbon fibers, and / or a metal-based conductive material including perovskite materials such as tin, tin oxide, titanium oxide, LaSrCoO3, and LaSrMnO3. The carbon nanotubes (CNTs) may include at least one selected from the group consisting of multi-walled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs) depending on the number of walls.

[0264] A separator (21, 22) according to one embodiment may mean a membrane formed in the form of a sheet to prevent electrical short circuit between a cathode and an anode and to allow an electron transport material to pass through. Here, the electron transport material may be, for example, lithium ions (Li + ), sodium ions (Na + ) or potassium ions (K + ) may be. The separator (21, 22) is not particularly limited as long as it is used in the art, and it is preferable that it has low resistance to ion movement of the electrolyte and excellent wettability of the electrolyte (particularly, electrolyte solution). The separator (21, 22) may each independently be a porous polymer film, for example, a porous polymer film made of a polyolefin material such as an ethylene polymer, a propylene polymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, or an ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof.

[0265] The negative electrode structure (10A) may be formed by the negative electrode (10) (or negative electrode sheet (10S)) according to an embodiment of the present application. For example, the negative electrode (10) (or negative electrode sheet (10S)) forming the negative electrode structure (10A) may include a first metal layer (100) and a second metal layer (200) that overlaps and is bonded to a portion of one edge of the first metal layer (100). For example, the negative electrode (10) (or negative electrode sheet (10S)) forming the negative electrode structure (10A) may be interposed between two separators (21, 22), as illustrated in FIG. 36. The negative electrode (10) (or negative electrode sheet (10S)) according to one embodiment may include a plurality of second metal layers (200), and the first metal layer (100) may be interposed between the plurality of second metal layers (200). According to another embodiment, the cathode (10) (or cathode sheet (10S)) includes a plurality of first metal layers (100), and a second metal layer (200) may be interposed between the plurality of first metal layers (100).

[0266] An electrode assembly (1) according to one embodiment can be manufactured, for example, by zigzag-bending (folding) a cathode structure (10A) and then inserting an anode (30) cut to an appropriate size into a space formed by the bending. Since the cathode (10) (or, cathode sheet (10S)) forming the cathode structure (10A) includes a first metal layer (100), it can be manufactured in a curved shape due to its soft nature.

[0267] Since the anode (30) is not easy to fold and is relatively easy to cut compared to the cathode structure (10A), it can be used by cutting it to an appropriate size as described above.

[0268] Meanwhile, the cathode structure (10A) including the sheet-shaped cathode (10) can be cut within an appropriate range after forming a bend and inserting an appropriate number of cathodes (30) between the surfaces formed by the bend. For example, referring to FIG. 36, after four cathodes (30) are inserted so that the cathode structure (10A) is in a form that completely surrounds the cathode (30), both ends of the cathode structure (10A) can be cut to manufacture an individual electrode assembly (1).

[0269] According to one embodiment, a cathode structure (10A) may include a stack portion (10A_S) and a folding portion (10A_F). The stack portions (10A_S) and the folding portions (10A_F) may each be provided in multiple numbers. The stack portion (10A_S) may form a laminated structure with the inserted cathode (30), and the folding portion (10A_F) may refer to an area where the cathode structure (10A) is folded. The electrode assembly (1) may have a structure in which the stack portions (10A_S) and the cathode (30) of the cathode structure (10A) are alternately and sequentially laminated.

[0270] The electrode assembly (1) according to one embodiment is not limited to the above-described method and can be assembled in various ways. For example, the electrode assembly (1) can be assembled by manufacturing a mono-cell in which a separator, a cathode (10) (for example, each cathode (10) illustrated in FIGS. 11, 23, and 35), a separator, and an anode are sequentially stacked, or a bi-cell in which a cathode (10) (for example, each cathode (10) illustrated in FIGS. 11, 23, and 35), a separator, and an anode are sequentially stacked, and then attaching a half-cell in which a separator, a cathode (10), and a separator are sequentially stacked to the mono-cell or bi-cell, and repeatedly stacking the mono-cells or bi-cells and then stacking up to the attached half-cells. In addition, for example, the electrode assembly (1) may be assembled by alternately stacking the negative electrode (10) (for example, each negative electrode (10) illustrated in FIGS. 11, 23, and 35) and the positive electrode between long sheet-shaped separators in a zigzag pattern. Even in the case of the above-described assembly method, the negative electrode (10) can minimize the phenomenon of separation due to its unique structure, and damage to the appearance during stacking can be reduced. The electrode assembly (1) according to one embodiment may be embedded in a case together with an electrolyte to manufacture a battery cell. In addition, a battery module, a battery pack, or an energy storage device, etc. may be manufactured using the battery cell.

[0271] In one embodiment, the battery cell may include a case housing an electrode assembly (1). Additionally, the battery cell may include an electrolyte within the case. The electrolyte may include one or more solid and liquid substances at room temperature and pressure. For example, the electrolyte may include a liquid substance. The electrolyte may include a conductive salt and a solvent.

[0272] Conductive salts may include electron transporting substances, for example, MCl, MBr, MI, MClO4, MBF4, MB 10Cl 10 , MB(Ph)4 (Ph is a phenol group), MC4BO8, MPF6, MCF3SO3, MCF3CO2, MAsF6, MSbF6, MAlCl4, MSO3CH3, MSO3CF3, MSCN, MC(CF3SO2)3, MN(CF3SO2)2, MN(C2F5SO2)2, MN(SO2F)2, chloroborane metal (M), lower aliphatic carboxylic acid metal (M), tetraphenyl borate metal (M) and metal (M) imide may be included, but is not particularly limited as long as it can be easily dissolved in an organic solvent, and the metal (M) is one of lithium (Li), sodium (Na) and potassium (K). The concentration of the conductive salt can vary in the range of 0.1 to 10 M depending on several factors such as solubility of the salt, conductivity of the dissolved salt, charge and discharge conditions of the battery, operating temperature and other factors known in the art of lithium secondary batteries.

[0273] The solvent may include one or more of a carbonate solvent, an ether solvent, and an ester solvent. The electrolyte may further include an appropriate solvent considering appropriate viscosity and electrical conductivity.

[0274] The carbonate solvent may include at least one of a cyclic carbonate solvent and a linear carbonate solvent. The cyclic carbonate solvent may include, for example, at least one of ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate (1,2-BC), 2,3-butylene carbonate (2,3-BC), 1,2-pentylene carbonate (1,2-PTC), 2,3-pentylene carbonate (2,3-PTC), and vinylene carbonate (VC). The linear carbonate solvent may include, for example, one or more of methyl carbonate, ethyl carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethylmethyl carbonate (EMC), methylpropyl carbonate (MPC), and ethylpropyl carbonate (EPC).

[0275] The ether solvent may include one or more of dimethyl ether, diethyl ether, dipropyl ether, methylethyl ether, methylpropyl ether, and ethylpropyl ether.

[0276] The ester solvent may include one or more of a linear ester solvent and a cyclic ester solvent. For example, the linear ester compound may include one or more of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate. Furthermore, for example, the cyclic ester compound may include one or more of, for example, gamma-buturolactone, gamma-valerolactone, gamma-caprolactone, sigma-valerolactone, and epsilon-caprolactone.

[0277] In one embodiment, the electrolyte may optionally include the aforementioned sulfur compound. In another embodiment, the electrolyte may optionally further include a nitric acid or nitrite compound. For example, the nitric acid or nitrite compound may include, but is not particularly limited to, inorganic nitric acid or nitrite compounds such as lithium nitrate (LiNO3), potassium nitrate (KNO3), cesium nitrate (CsNO3), barium nitrate (Ba(NO3)2), ammonium nitrate (NH4NO3), lithium nitrite (LiNO2), potassium nitrite (KNO2), cesium nitrite (CsNO2), and ammonium nitrite (NH4NO2); organic nitric acid or nitrite compounds such as methyl nitrate, dialkyl imidazolium nitrate, guanidine nitrate, imidazolium nitrate, pyridinium nitrate, ethyl nitrite, propyl nitrite, butyl nitrite, pentyl nitrite, and octyl nitrite; It may include one or more of organic nitro compounds such as nitromethane, nitropropane, nitrobutane, nitrobenzene, dinitrobenzene, nitropyridine, dinitropyridine, nitrotoluene, and dinitrotoluene.

[0278] Additionally, in one embodiment, the electrolyte may further include other additives to improve charge / discharge characteristics or flame retardancy, as the case may be. The other additives may include, but are not limited to, one or more of pyridine, triethylphosphite, triethanolamine, cyclic ethers, ethylene diamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, aluminum trichloride, fluoroethylene carbonate (FEC), and propene sultone (PRS).

[0279] The negative electrode (10), the negative electrode sheet (10S), and the electrode assembly (1) according to one embodiment of the present application can be widely applied to green technology fields such as electric vehicles, battery charging stations, and other solar and wind power generation using batteries. In addition, the negative electrode (10), the negative electrode sheet (10S), and the electrode assembly (1) according to one embodiment of the present application can be applied to eco-friendly electric vehicles or hybrid vehicles for preventing climate change by suppressing air pollution and greenhouse gas emissions.

[0280] While various embodiments of the present application have been described in detail above, the scope of the present application is not limited thereto, and it will be apparent to those skilled in the art that various modifications and variations are possible without departing from the technical spirit of the present application as set forth in the claims. Furthermore, the above-described embodiments may be implemented by deleting some components, and the embodiments may be implemented in combination with each other.

[0281] [Explanation of symbols]

[0282] 1... Electrode assembly 10... Cathode

[0283] 10S... negative electrode sheet 100... first metal layer

[0284] 100a... 1-1 metal layer 100b... 1-2 metal layer

[0285] 200... 2nd metal layer 200a... 2nd-1 metal layer

[0286] 200b... 2nd-2nd metal layer 210... 1st region

[0287] 220... second zone 230... negative tab

Claims

1. A first metal layer formed of lithium metal and It comprises a plurality of second metal layers formed of a material other than the lithium metal and bonded to overlap a portion of the first metal layer, The cathode, wherein the first metal layer is interposed between the plurality of second metal layers.

2. In paragraph 1, The above plurality of second metal layers are formed of a metal having a lower reactivity than the lithium metal, and are a negative electrode.

3. In paragraph 1, Each of the plurality of second metal layers includes a first region overlapping the first metal layer and a second region other than the first region, A cathode, wherein at least one of the plurality of second metal layers is formed such that the widthwise length of the first region is shorter than the widthwise length of the second region.

4. In paragraph 3, A cathode, wherein at least one first region of the plurality of second metal layers is embedded in the first metal layer.

5. In paragraph 3, The first region of each of the plurality of second metal layers has a widthwise length that is substantially the same as that of the cathode.

6. In paragraph 3, A cathode comprising a cathode tab formed in at least one second region among the plurality of second metal layers.

7. In paragraph 6, A cathode comprising a margin region, which is a region other than a region corresponding to the cathode tab, in at least one of the second regions among the plurality of second metal layers.

8. A plurality of first metal layers formed of lithium metal, A second metal layer formed of a material other than the lithium metal, including a first region overlapping at least one of the plurality of first metal layers and a second region other than the first region, and interposed between the plurality of first metal layers and bonded to the plurality of first metal layers; and In the second region, a margin region is provided adjacent to at least one of the plurality of first metal layers, cathode.

9. In paragraph 8, The second metal layer is formed of a metal having a lower reactivity than the lithium metal, and is a negative electrode.

10. In paragraph 8, A cathode further comprising a cathode tab formed in the second region.

11. In paragraph 10, A cathode, wherein when viewed in the thickness direction of one of the first metal layers, at least a portion of the margin region is provided between the cathode tab and one of the first metal layers, or between the cathode tab and the first region.

12. In paragraph 8, At least a portion of the first region includes one or more of a predetermined pattern structure and a surface-treated region, cathode.

13. In paragraph 8, A cathode in which the width direction length of the first region is formed shorter than the width direction length of the second region.

14. Including a first metal layer and a second metal layer that overlaps and forms a bond with a portion of one edge of the first metal layer, The second metal layer includes a first region overlapping the first metal layer and a second region other than the first region, A negative electrode sheet in which a negative tab including a first tab, a second tab, and a third tab is formed in the second region, and the second tab and the third tab, which are adjacent to each other on both sides of the first tab, are each positioned spaced apart from the first tab by a predetermined distance, and a first length, which is a distance between the first tab and the second tab, is formed to be longer than a second length between the first tab and the third tab.

15. In paragraph 14, A cathode sheet, wherein the second metal layer is formed of a metal having lower reactivity than the first metal layer.

16. Contains anode, cathode and separator, The negative electrode includes a first metal layer formed of lithium metal and a second metal layer formed by bonding and overlapping a portion of one edge of the first metal layer, wherein the second metal layer is formed of a metal having a lower reactivity than the lithium metal and is interposed between two of the separators to form a negative electrode structure. The above cathode structure includes a stack portion and a folding portion, An electrode assembly having a structure in which the stack portion and the anode are sequentially stacked alternately.

17. In paragraph 16, An electrode assembly, wherein the stack portion and the folding portion are each provided in multiple units.

18. In paragraph 16, An electrode assembly, wherein the cathode comprises a plurality of second metal layers, and the first metal layer is interposed between the plurality of second metal layers.

19. In paragraph 16, An electrode assembly, wherein the cathode comprises a plurality of first metal layers, and the second metal layer is interposed between the plurality of first metal layers.

20. In paragraph 16, The above positive electrode includes a positive electrode active material layer including a positive electrode active material and a positive electrode current collector supporting the positive electrode active material layer, The above positive electrode active material is an electrode assembly containing a sulfur compound.

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