Anode for lithium metal battery, electrode assembly for lithium metal battery, and lithium metal battery

Abstract

The present application may provide an anode for a lithium metal battery and an electrode assembly for a lithium metal battery, in which, in a battery system using lithium metal as the anode, the anode includes a main body portion and an anode tab extending from one side edge of the main body portion, connected to a metal lead, and including lithium metal, wherein the anode tab is configured such that the width (W1) of the end portion thereof and the width (W2) of a connection portion connecting the end portion and the main body portion are different, thereby preventing the problem of the tab deviating from the range of the lead and spreading when the anode tab and the lead are welded, thus enabling problems occurring during sealing and adverse effects on battery performance to be minimized.

Description

Anode for lithium metal battery, electrode assembly for lithium metal battery and lithium metal battery

[0001] Cross-citation with related applications

[0002] This application is based on and claims the benefit of priority from Korean Patent Application Nos. 10-2024-0001107 and 10-2025-0000904, filed with the Korean Intellectual Property Office on January 3, 2024 and January 3, 2025, respectively, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present application relates to a negative electrode for a lithium metal battery, an electrode assembly for a lithium metal battery, and a lithium metal battery including at least one of the negative electrode and the 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 advantages over nickel-based batteries, including virtually no memory effect, free charging and discharging, a very low self-discharge rate, and high energy density.

[0007] Batteries are manufactured according to the output and specifications required in various fields. To ensure the desired output, electrode tabs are electrically connected by welding to leads. These leads are typically made of metal.

[0008] Meanwhile, lithium metal batteries use metallic lithium as the anode. While metallic lithium is highly advantageous for increasing energy density, it is softer than the copper (Cu) commonly used in the past. This can cause the anode tab and lead to spread during welding, potentially extending beyond the lead's range. This can cause sealing problems and degrade overall battery performance.

[0009] The present application provides a lithium metal battery anode, an electrode assembly for a lithium metal battery, and a lithium metal battery, which can minimize problems occurring during sealing or negative effects on battery performance by preventing the tab from spreading beyond the range of the lead when welding the tab and the lead in a battery system using lithium metal as an anode.

[0010] A negative electrode for a lithium metal battery according to one embodiment of the present application includes a main body and a negative electrode tab extending from one edge of the main body and connected to a metal lead and including lithium metal, wherein the negative electrode tab may be configured such that a width (W1) of an end portion and a width (W2) of a connecting portion connecting the end portion and the main body portion are different.

[0011] In an anode for a lithium metal battery according to one embodiment of the present application, the width (W1) of the end portion may be narrower than the width (W2) of the connection portion.

[0012] In a negative electrode for a lithium metal battery according to one embodiment of the present application, the ratio (W1 / W2) of the width (W1) of the end portion and the width (W2) of the connection portion may be within a range of 0.1 to 0.6.

[0013] In an anode for a lithium metal battery according to one embodiment of the present application, the anode tab may have a shape in which the width gradually decreases in a direction away from the main body.

[0014] An electrode assembly for a lithium metal battery according to one embodiment of the present application includes a main body and a negative electrode for a lithium metal battery having a negative electrode tab extending from one edge of the main body and including lithium metal, and a metal lead connected to the negative electrode tab, and a connection area (A) where the metal lead and the negative electrode tab are connected C ) may not extend beyond the outer boundary of the metal lead.

[0015] In an electrode assembly for a lithium metal battery according to one embodiment of the present application, the negative electrode tab is joined to a metal lead by welding, and the negative electrode tab before being joined by welding may be configured such that a width (W1) of an end portion is narrower than a width (W2) of a connecting portion connecting the end portion and the main body portion.

[0016] In an electrode assembly for a lithium metal battery according to one embodiment of the present application, in the negative electrode tab after being joined by welding, the width (W1') of the end portion is equal to the width (W) of the metal lead at a position corresponding to the end portion. L ) may be equal to or less than .

[0017] In an electrode assembly for a lithium metal battery according to one embodiment of the present application, the width (W1') of the end portion and the width (W) of the metal lead L ) ratio (W1' / W L ) can be in the range of 0.5 to 1.

[0018] In an electrode assembly for a lithium metal battery according to one embodiment of the present application, a connection area (A) for the area (A2) of the negative electrode tab C ) may be greater than 50%.

[0019] An electrode assembly for a lithium metal battery according to one embodiment of the present application comprises a first negative electrode and a second negative electrode, and a metal lead for a lithium metal battery, the negative electrode including a plurality of negative electrodes having a structure in which the negative electrodes are stacked one by one, wherein the plurality of negative electrodes each include a main body and a negative electrode tab extending from one edge of the main body and including lithium metal, wherein the first negative electrode is positioned so that the negative electrode tab is in direct contact with and connected to the metal lead, and the second negative electrode is positioned at the outermost end of the stacked structure so as not to be in direct contact with the metal lead, and a connection area (A) in which the metal lead and the negative electrode tab of the first negative electrode are connected C ) may not extend beyond the outer boundary of the metal lead.

[0020] In an electrode assembly for a lithium metal battery according to one embodiment of the present application, the negative electrode tab of the first negative electrode is welded to a metal lead, and the plurality of negative electrodes are welded to form a laminated structure, and the negative electrode tab of the first negative electrode before being welded has a width (W) of an end portion 11 ) is the width (W) of the connecting portion connecting the end portion and the main body. 12 ) is configured to be narrower than the second cathode, and the cathode tab of the second cathode has a width (W) of the end portion 21 ) is the width (W) of the connecting portion connecting the end portion and the main body. 22 ) can be configured to be narrower.

[0021] In an electrode assembly for a lithium metal battery according to one embodiment of the present application, the plurality of negative electrodes are welded together so that the ends of each negative electrode tab are aligned to form a laminated structure, and each bonding area (A) bonded between the negative electrodes J ) is projected perpendicularly to the surface where the metal lead is located, forming a corresponding area (A E ) may not extend beyond the outer boundary of the metal lead.

[0022] In an electrode assembly for a lithium metal battery according to one embodiment of the present application, the width (W) of the end of the negative electrode tab of the first negative electrode before being joined by welding 11 ) is the width (W) of the end of the cathode tab of the second cathode 21 ) can be as wide as or wider than.

[0023] In an electrode assembly for a lithium metal battery according to one embodiment of the present application, the width (W1) of the end portion of each negative electrode tab of the plurality of negative electrodes before being joined by welding may gradually widen from the second negative electrode to the first negative electrode.

[0024] In an electrode assembly for a lithium metal battery according to one embodiment of the present application, the width (W) of the end of the negative electrode tab of the first negative electrode after being joined by welding 11 ') and the width (W) of the end of the cathode tab of the second cathode 21 ') is the width (W) of the metal lead at a position corresponding to the end of the negative tab of the first negative electrode. L ) may be equal to or less than .

[0025] An electrode for a lithium metal battery according to one embodiment of the present application may include at least one of the aforementioned lithium metal battery negative electrode and lithium metal battery electrode assembly. The lithium metal battery may be a lithium-sulfur battery or a lithium-air battery.

[0026] The present application, in a battery system using lithium metal as an anode, prevents the problem of the anode tab and lead from spreading out of the range of the lead when welding the tab, thereby minimizing problems occurring during sealing or negative effects on battery performance.

[0027] The drawings shown in this application are based on examples of this application, and the ratios of the width, depth, or thickness (or height) of each component are 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 is perpendicular to each other, the direction indicated by the arrow is the + direction, and the direction opposite to the direction indicated by the arrow (the direction rotated by 180 degrees) may be the - direction.

[0028] FIG. 1 is a plan view showing the front side of at least a portion of an electrode assembly for a lithium metal battery according to one embodiment of the present application.

[0029] FIGS. 2 and 3 are plan views showing the rear surface of at least a portion of an electrode assembly for a lithium metal battery according to one embodiment of the present application.

[0030] FIGS. 4 and 5 are perspective views illustrating at least a portion of an electrode assembly for a lithium metal battery according to one embodiment of the present application.

[0031] FIG. 6 is a plan view showing the rear surface of at least a portion of an electrode assembly for a lithium metal battery according to one embodiment of the present application.

[0032] 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 accordance with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concepts of terms 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 spirit of this application. Therefore, various equivalents and variations may exist at the time of filing of this application.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] Additionally, terms including ordinal numbers, such as "first," "second," etc., may be used in this specification and claims to distinguish between components. These ordinal numbers are used to distinguish identical or similar components from each other, and the use of these ordinal numbers should not be interpreted in a limited manner. For example, components associated with these ordinals should not be interpreted in a restricted manner, such as in the order of use or arrangement, based on their numbers. If necessary, each ordinal number may be used interchangeably.

[0037] Hereinafter, embodiments of the present application will be described in detail with reference to the attached drawings. However, the scope of the present application may not be limited to the presented embodiments. For example, those skilled in the art who understand the scope of the present application may propose other embodiments within the scope of the present application by adding, modifying, or deleting components, but such embodiments will also be considered within the scope of the present application. The shapes and sizes of elements in the drawings may be exaggerated for clarity.

[0038] In this specification, the term "battery" may be used interchangeably with "cell." Furthermore, "battery" or "cell" may collectively refer to a battery cell, which is a unit thereof, or a battery module or battery pack containing a battery cell.

[0039] FIG. 1 is a plan view showing the front side of at least a portion of an electrode assembly (10) for a lithium metal battery according to one embodiment of the present application. FIG. 2 is a plan view showing the rear side of at least a portion of an electrode assembly (10) for a lithium metal battery according to one embodiment of the present application. FIG. 2 shows the state before the metal lead (100) and the negative electrode (200) for a lithium metal battery are welded and connected, but only in contact.

[0040] An electrode assembly (10) for a lithium metal battery may include a metal lead (100) and a negative electrode (200) for a lithium metal battery. Meanwhile, although not shown in the drawing, the electrode assembly (10) for a lithium metal battery may include a positive electrode and a separator as needed, and a separator may be interposed between the positive electrode and the negative electrode (200) for a lithium metal battery.

[0041] The metal lead (100) may be connected to the negative electrode (200) for a lithium metal battery. Furthermore, they may be electrically connected. As used herein, "electrically connected" may refer to a state in which, when objects to be connected are connected by a connecting means, an electric circuit is formed, allowing current to flow through each object to be connected. The connecting means is not particularly limited as long as it allows electrical connection, but may be direct contact between objects to be connected, or a wire through which current can flow.

[0042] The metal lead (100) is not particularly limited as long as it is a conductive metal, and may include, for example, one or more selected from lithium (Li), nickel (Ni), aluminum (Al), copper (Cu), and iron (Fe).

[0043] The metal lead (100) and the negative electrode (200) for a lithium metal battery can be connected by joining by welding or the like. Welding is not particularly limited as long as it is used in the art, but considering that the negative electrode (200) for a lithium metal battery has a relatively soft characteristic, ultrasonic welding can be applied. While the metal lead (100) and the negative electrode (200) for a lithium metal battery are joined, an ultrasonic welding device applies pressure to the joined portion and vibrates the portion with ultrasonic waves at the same time, and welding can be performed with the frictional heat generated at this time. In particular, the ultrasonic welding device can include an anvil including a protrusion to prevent shaking of the welding target while maintaining the pressing force and to efficiently transmit ultrasonic waves to the welding target. The anvil is positioned so that the protrusion part contacts the joined portion of the metal lead (100) and the negative electrode (200) for a lithium metal battery, and can transmit ultrasonic waves to vibrate the joined portion while applying pressure to the joined portion.

[0044] The electrode assembly (10) for a lithium metal battery may further include an insulating film (300). The insulating film (300) may be provided in a form that wraps around a portion of the metal lead (100). Electrical short-circuiting of the electrode assembly (10) may be prevented through the insulating film (300). Meanwhile, the insulating film (300) may be provided in an area other than an area where the metal lead (100) and the negative electrode (200) for a lithium metal battery are connected. The insulating film (300) is not particularly limited as long as it is used in the art, but for example, a polyolefin material may be used.

[0045] A negative electrode (200) for a lithium metal battery may include a main body (210) and a negative electrode tab (220). The negative electrode tab (220) may extend from one edge of the main body (210). In addition, the negative electrode tab (220) may be connected to a metal lead (100) and may have a connecting portion provided to be connected to the metal lead (100).

[0046] The main body (210) may include lithium metal. The negative electrode tab (220) may include lithium metal. The main body (210) and the negative electrode tab (220) may be integrally formed. For example, a lithium metal sheet may be cut to obtain a negative electrode (200) for a lithium metal battery that integrally includes the main body (210) and the negative electrode tab (220). The method for cutting the lithium metal sheet is not particularly limited as long as it is used in the art, but, for example, an ultrasonic cutting method may be applied. For an example of an ultrasonic cutting method, reference may be made to Korean Patent Publication No. 10-2022-0035741.

[0047] Meanwhile, the negative electrode (200) for a lithium metal battery is not particularly limited, but may have a thickness of about 40 ㎛ to 60 ㎛ or 45 to 50 ㎛.

[0048] The metal lead (100) may be connected to the negative electrode tab (220). Specifically, the metal lead (100) may be connected to at least a portion of the negative electrode tab (220), and may be connected by joining, for example, by welding. As a result, the metal lead (100) and the negative electrode tab (220) may be electrically connected, and ultimately, the metal lead (100) and the negative electrode (200) for a lithium metal battery may be electrically connected.

[0049] Meanwhile, when the negative electrode tab (220) including lithium metal is connected to the metal lead (100), the negative electrode tab (220) may spread due to the soft nature of the lithium metal, and as a result, the spread negative electrode tab (220) may detach from the metal lead (100), which may cause a sealing problem during battery cell manufacturing and may cause a deterioration in overall battery performance. The negative electrode (200) for a lithium metal battery according to one embodiment of the present application may have a specific shape to prevent such a problem.

[0050] In the negative electrode (200) for a lithium metal battery, the negative electrode tab (220) may be configured such that the width (W1) of the end portion (221) and the width (W2) of the connecting portion (222) connecting the end portion (221) and the main body (210) are different. That is, the negative electrode tab (220) before welding may be configured such that the width (W1) of the end portion (221) and the width (W2) of the connecting portion (222) connecting the end portion (221) and the main body (210) are different. The connecting portion (222) may mean a boundary between the negative electrode tab (220) and the main body (210).

[0051] The width (W1) of the end portion (221) may be configured to be narrower than the width (W2) of the connection portion (222). That is, the width (W1) of the end portion (221) before welding may be configured to be narrower than the width (W2) of the connection portion (222). Since the negative electrode tab (220) has this shape, the negative electrode tab (220) can be prevented from detaching from the metal lead (100) even due to the soft nature of lithium metal.

[0052] In the negative tab (220), the ratio (W1 / W2) of the width (W1) of the end portion (221) to the width (W2) of the connection portion (222) may be within a range of 0.1 to 0.6, 0.2 to 0.55, or 0.3 to 0.5. That is, in the negative tab (220) before welding, the ratio (W1 / W2) of the width (W1) of the end portion (221) to the width (W2) of the connection portion (222) may be within the aforementioned range. When the ratio (W1 / W2) of the width (W1) of the end portion (221) to the width (W2) of the connection portion (222) satisfies the aforementioned range, it is possible to ensure excellent connection quality (bonding or welding quality) while preventing the negative tab (220) from detaching from the metal lead (100) despite the soft nature of lithium metal.

[0053] In the negative tab (220), the ratio (W1 / W3) of the width (W1) of the end portion (221) to the width (W3) of the main body portion (210) may be within a range of 0.01 to 0.5, 0.02 to 0.4, 0.03 to 0.3, 0.04 to 0.2, or 0.05 to 0.1. That is, in the negative tab (220) before welding, the ratio (W1 / W3) of the width (W1) of the end portion (221) to the width (W3) of the main body portion (210) may be within the above-mentioned range. If the ratio (W1 / W3) of the width (W1) of the end portion (221) and the width (W3) of the main body portion (210) satisfies the above-mentioned range, the negative electrode tab (220) can be prevented from leaving the metal lead (100) despite the soft nature of lithium metal.

[0054] In the negative tab (220), the ratio (W2 / W3) of the width (W2) of the connection portion (222) to the width (W3) of the main body portion (210) may be within a range of 0.05 to 0.5, 0.06 to 0.45, 0.07 to 0.4, 0.08 to 0.35, 0.09 to 0.3, 0.1 to 0.25, 0.11 to 0.2, or 0.12 to 0.18. That is, in the negative tab (220) before welding, the ratio (W2 / W3) of the width (W2) of the connection portion (222) to the width (W3) of the main body portion (210) may be within the above-mentioned range. If the ratio (W2 / W3) of the width (W2) of the connecting portion (222) and the width (W3) of the main body portion (210) satisfies the above-mentioned range, the negative electrode tab (220) can be prevented from leaving the metal lead (100) even with the soft characteristics of lithium metal.

[0055] The negative electrode tab (220) may have a shape in which the width gradually decreases in the direction away from the main body (210). That is, the negative electrode tab (220) before welding may have a shape in which the width gradually decreases in the direction away from the main body (210). Referring to FIG. 2, which illustrates the appearance before the metal lead (100) and the negative electrode (200) for a lithium metal battery are welded and joined, the negative electrode tab (220) may be configured such that the width (W1) of the end portion (221) is narrower than the width (W2) of the connection portion (222), and may have a shape in which the width gradually decreases in the direction away from the main body (210) (i.e., the +y direction in FIG. 2). Here, the meaning of a gradual decrease in width may mean that the width of a specific point between the end portion (221) and the connection portion (222) is greater than the width (W1) of the end portion (221), the width (W2) of the connection portion (222) is narrower, and the width becomes narrower the closer it is to the end portion (221) continuously or discontinuously. For example, the negative tab (220) may have a shape in which the width gradually decreases continuously at a constant ratio as shown in FIG. 2, i.e., a trapezoidal negative tab (220) shape. Alternatively, the side boundary of the negative tab (220) may have a shape that is concave inward or convex outward, as needed.

[0056] Alternatively, unlike FIG. 2, the negative tab (220) may have a shape in which the width gradually decreases in a discontinuous step shape.

[0057] FIG. 3 is a plan view showing the rear surface of at least a portion of an electrode assembly (10) for a lithium metal battery according to one embodiment of the present application. FIG. 3 shows the appearance after a metal lead (100) and a negative electrode (200) for a lithium metal battery are welded together.

[0058] An electrode assembly (10) for a lithium metal battery may include a main body (210), a negative electrode (200) for a lithium metal battery having a negative electrode tab (220) extending from one edge of the main body (210) and including lithium metal, and a metal lead (100) connected to the negative electrode tab (220). In the electrode assembly (10) for a lithium metal battery, a connection area (A) where the metal lead (100) and the negative electrode tab (220) are connected C ) may not go beyond the outer boundary of the metal lead (100). That is, even if the metal lead (100) and the negative tab (220) are connected by welding or the like, the connection area (A C ) may not extend beyond the outer boundary of the metal lead (100). The connection area (A C ) may refer to an area where the metal lead (100) and the negative tab (220) are joined by welding or the like.

[0059] Connection area (A) to the area (A2) of the negative tab (220) C ) may be 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, or 90% or more. The area (A2) of the negative tab (220) refers to the entire area of ​​one side that comes into contact with the metal lead (100). The connection area (A C ) and the area (A2) of the cathode tab (220) satisfy the above ratio, excellent connection quality (bonding or welding quality) can be secured.

[0060] In the electrode assembly (10) for a lithium metal battery, the negative electrode tab (220) can be joined to the metal lead (100) by welding. In addition, the negative electrode tab (220) before being joined by welding can have the characteristics of the negative electrode (200) for a lithium metal battery described above. That is, for example, the negative electrode tab (220) before being joined by welding can be configured such that the width (W1) of the end portion (221) is narrower than the width (W2) of the connecting portion (222) connecting the end portion (221) and the main body portion (210).

[0061] Meanwhile, in the process of welding the negative electrode tab (220) to the metal lead (100), the width (W1) of the end (221) of the negative electrode tab (220) may be larger than before welding due to the soft nature of lithium metal. The width (W1') of the end (221) of the negative electrode tab (220) after welding may be larger than the width (W1) of the end (221) before welding. Referring to FIG. 3, in the negative electrode tab (220) after welding, the width (W1') of the end (221) is greater than the width (W1) of the metal lead (100) at the position corresponding to the end (221). L ) may be equal to or smaller than the negative tab (220). That is, the negative tab (220) may not go beyond the outer boundary of the metal lead (100) even after being joined by welding. The position of the metal lead (100) corresponding to the end portion (221) may mean a position where a shape obtained by vertically projecting the end portion (221) onto the metal lead (100) overlaps with the metal lead (100).

[0062] The width (W1') of the end (221) of the negative tab (220) that is joined by welding and the width (W) of the metal lead (100) L ) ratio (W1' / W L ) can be in the range of 0.5 to 1, 0.6 to 1, 0.7 to 1, 0.8 to 1 or 0.9 to 1. The width (W1') of the end (221) of the negative tab (220) and the width (W) of the metal lead (100) that are completed by welding satisfying the above ranges L ) ratio (W1' / W L ) may mean that the negative tab (220) does not come off the metal lead (100) despite the soft nature of lithium metal while ensuring excellent connection quality (bonding or welding quality). The above ratio (W1' / W L ) can be implemented through welding of the aforementioned lithium metal battery negative electrode (200) and metal lead (100).

[0063] FIG. 4 is a perspective view illustrating at least a portion of an electrode assembly (10) for a lithium metal battery according to one embodiment of the present application. FIG. 4 illustrates a state before a metal lead (100) and a negative electrode (200) for a lithium metal battery are welded and joined. FIG. 5 is a perspective view illustrating at least a portion of an electrode assembly (10) for a lithium metal battery according to one embodiment of the present application. FIG. 5 illustrates a state after a metal lead (100) and a negative electrode (200) for a lithium metal battery are welded and joined. FIG. 6 is a plan view illustrating a rear surface of at least a portion of an electrode assembly (10) for a lithium metal battery according to one embodiment of the present application. FIG. 6 illustrates a state in which a metal lead (100) and a negative electrode (200) for a lithium metal battery are welded and joined.

[0064] An electrode assembly (10) for a lithium metal battery may include a lithium metal battery negative electrode (200) including a plurality of negative electrodes and a metal lead (100). The plurality of negative electrodes may include a first negative electrode (200_1) and a second negative electrode (200_2), and may have a structure in which they are stacked one by one.

[0065] All of the negative electrodes constituting the plurality of negative electrodes including the first negative electrode (200_1) and the second negative electrode (200_2) may each include a main body (210) and a negative electrode tab (220) extending from one edge of the main body (210) and including lithium metal. That is, the first negative electrode (200_1) may include the main body (210_1) and the negative electrode tab (220_1), and the second negative electrode (200_2) may include the main body (210_2) and the negative electrode tab (220_2).

[0066] The first cathode (200_1) may be positioned so that the cathode tab (220_1) is in direct contact with and connected to the metal lead (100). That is, among the plurality of cathodes, the cathode that is in direct contact with the metal lead (100) may be the first cathode (200_1). The cathode tab (220_1) of the first cathode (200_1) may be connected to the metal lead (100) by welding or the like.

[0067] The second cathode (200_2) may be located at the outermost end of a plurality of cathodes having a stacked structure and may not be in direct contact with the metal lead (100).

[0068] A plurality of negative electrodes can be joined by welding to form a laminated structure. Specifically, the plurality of negative electrodes can be joined by welding so that the ends (221) of the respective negative electrode tabs (220) match, thereby forming a laminated structure. That is, the plurality of negative electrodes can be arranged in a laminated manner so that the ends (221) of the respective negative electrode tabs (220) match, and then the negative electrode tabs (220) of the respective negative electrodes can be electrically connected through welding to form a laminated structure. When the first negative electrode (200_1) is welded to the metal lead (100), the plurality of negative electrodes are also welded simultaneously, so that ultimately the negative electrode (200) for a lithium metal battery can be electrically connected to the metal lead (100).

[0069] Meanwhile, when the negative electrode (200) for a lithium metal battery includes a plurality of negative electrodes, each negative electrode may independently have the characteristics of the aforementioned negative electrode (200) for a lithium metal battery. For example, before being joined by welding, each negative electrode tab (220) of the plurality of negative electrodes may be configured so that the width (W1) of the end portion (221) and the width (W2) of the connecting portion (222) connecting the end portion (221) and the main body (210) are different. That is, before being joined by welding, the negative electrode tab (220_1) of the first negative electrode (200_1) has a width (W) of the end portion (221_1) 11 ) The width (W) of the connecting portion (222_1) connecting the end portion (221_1) and the main body portion (210_1)12 ) can be configured to be narrower than the first cathode (200_2). In addition, before being joined by welding, the cathode tab (220_2) of the second cathode (200_2) has a width (W) of the end (221_2) 21 ) The width (W) of the connecting portion (222_2) connecting the end portion (221_2) and the main body portion (210_2) 22 ) can be configured to be narrower.

[0070] The width (W) of the end (221_1) of the cathode tab (220_1) of the first cathode (200_1) before welding 11 ) is the width (W) of the end (221_2) of the cathode tab (220_2) of the second cathode (200_2). 21 ) may be the same.

[0071] Alternatively, the width (W) of the end (221_1) of the cathode tab (220_1) of the first cathode (200_1) 11 ) is the width (W) of the end (221_2) of the cathode tab (220_2) of the second cathode (200_2). 21 ) may be different. For example, the width (W) of the end (221_1) of the cathode tab (220_1) of the first cathode (200_1) 11 ) is the width (W) of the end (221_2) of the cathode tab (220_2) of the second cathode (200_2). 21 ) can be wider than the contrast.

[0072] Meanwhile, the width (W1) of the end portion (221) of each cathode tab (220) of the plurality of cathodes before being joined by welding may gradually widen from the second cathode (200_2) located at the outermost end to the first cathode (200_1). Here, the meaning of the width gradually widening may mean that the width (W1) of the end portion (221) of the cathode tab (220) continuously or discontinuously widens from the second cathode (200_2) to the first cathode (200_1). For example, in the case of including a plurality of cathodes, the width (W1) of the end portion (221) of the cathode tab (220) may be in a form in which the width gradually decreases continuously at a constant ratio from the second cathode (200_2) to the first cathode (200_1), or may be in a form in which the width gradually decreases discontinuously in a step-like manner.

[0073] In the process of welding the first negative electrode (200_1) with the metal lead (100) and welding multiple negative electrodes, the width (W1) of the end portion (221) of each negative electrode tab (220) of the multiple negative electrodes may increase compared to before welding due to the soft nature of lithium metal. Referring to FIGS. 5 and 6, the width (W) of the end portion (221_1) of the negative electrode tab (220_1) of the first negative electrode (200_1) that has been completed by welding 11 ') is the width before welding (W 11 ) may be larger than that. In addition, the width (W) of the end (221_2) of the cathode tab (220_2) of the second cathode (200_2) that is completed by welding 21 ') is the width before welding (W 21 ) can be greater than.

[0074] Referring to Fig. 6, the width (W) of the end (221_1) of the cathode tab (220_1) of the first cathode (200_1) after being joined by welding 11 ') is the width (W) of the metal lead (100) corresponding to the end (221_1) L) may be equal to or smaller than that. In addition, the width (W) of the end (221_2) of the cathode tab (220_2) of the second cathode (200_2) after being joined by welding 21 ') is the width (W) of the metal lead (100) corresponding to the end (221_1) of the negative tab (220_1) of the first cathode (200_1). L ) may be equal to or smaller than that. That is, each of the negative electrode tabs (220_1, 220_2) of the first negative electrode (200_1) and the second negative electrode (200_2) may not go beyond the outer boundary of the metal lead (100) even after being joined by welding. The position of the metal lead (100) corresponding to the end portion (221_1) of the negative electrode tab (220_1) of the first negative electrode (200_1) may mean a position where a shape obtained by vertically projecting the end portion (221_1) onto the metal lead (100) overlaps with the metal lead (100). Even when an additional negative electrode is provided between the first negative electrode (200_1) and the second negative electrode (200_2) in a plurality of negative electrodes, the additionally provided negative electrode may have the above-described characteristics.

[0075] In addition, when the negative electrode (200) for a lithium metal battery includes a plurality of negative electrodes, the first negative electrode (200_1) joined to the metal lead (100) may have characteristics between the metal lead (100) and the negative electrode (200) for a lithium metal battery. For example, in the electrode assembly (10) for a lithium metal battery, a connection area (A) where the negative electrode tab (220_1) of the metal lead (100) and the first negative electrode (200_1) are connected C ) may not go beyond the outer boundary of the metal lead (100). That is, even if the metal lead (100) and the negative tab (220_1) of the first negative electrode (200_1) are connected by welding or the like, the connection area (A C ) may not extend beyond the outer boundary of the metal lead (100). The connection area (A C ) may refer to an area where the metal lead (100) and the negative electrode tab (220_1) of the first negative electrode are joined by welding or the like.

[0076] A plurality of cathodes having a laminated structure can be formed by welding so that the ends (221) of each cathode tab (220) match. Here, the bonding area (A) bonded between each cathode J ) can be formed. That is, the bonding area (A J ) may mean a bonded area between one of the plurality of cathodes and another cathode bonded to the cathode. Bonding area (A J ) is projected perpendicularly to the surface where the metal lead (100) is located, the corresponding area (A E ) can be formed. That is, referring to Fig. 6, the bonding area (A J ) is projected in the -z direction as it is, and the area when it touches the surface where the metal lead (100) is located is the corresponding area (A E ) can be said to be. Here, the corresponding area (A E ) may not extend beyond the outer boundary of the metal lead (100). The bonding area (A J ) even if there are multiple joint areas (A J ) formed by each corresponding area (A E ) may not extend beyond the outer boundary of the metal lead (100).

[0077] A lithium metal battery according to an example of the present application may include at least one of the aforementioned lithium metal battery negative electrode (200) and lithium metal battery electrode assembly (10). The type of the lithium metal battery is not particularly limited, but may be a lithium-sulfur battery or a lithium-air battery, etc.

[0078]

[0079] [Example Exam]

[0080] Example 1.

[0081] Seven pre-weld cathodes were prepared, each having a cathode tab having a width (W1) of about 3 mm at the tip, a width (W2) of the connection connecting the tip and the main body of about 6 mm (i.e., W1 / W2 = about 0.5), and a ratio (W2 / W3) of the width of the connection (W2) to the width (W3) of the main body of about 0.15. All of the prepared cathodes were made of lithium metal, and each had a thickness of about 45 to 50 μm. The seven cathodes were stacked one after the other so that their tips coincided, and the cathode located at the bottom was brought into contact with the tip of the metal lead. The tip of the cathode was positioned at a distance of about 2.5 mm inward from the tip of the metal lead. In addition, the metal lead had a width of about 6 mm, and an insulating film was installed at a distance of about 3 mm inward from the tip.

[0082] The area in contact with the metal lead from the end of the cathode (i.e., the connection area (A) C )) The anvil of the ultrasonic welding device was positioned, and ultrasonic welding was completed by transmitting ultrasonic waves while the anvil applied pressure to the area. As ultrasonic welding was performed, the width of the end of the cathode gradually widened.

[0083] After welding was completed, the width (W1') of the end of the cathode located at the outermost end was approximately 6 mm, and all cathodes did not extend beyond the outer boundary of the metal lead, indicating excellent welding quality.

[0084] Example 2.

[0085] Ultrasonic welding was completed in the same manner as in Example 1, except that 7 pre-welding cathodes were prepared, each having a cathode tab having a width (W1) of about 2 mm at the end, a width (W2) of the connection connecting the end and the main body of about 6 mm (i.e., W1 / W2=0.33), and a ratio (W2 / W3) of the width (W2) of the connection to the width (W3) of the main body of about 0.15.

[0086] After welding was completed, the width (W1') of the end of the cathode located at the outermost end was approximately 5.5 mm, and all cathodes did not extend beyond the outer boundary of the metal lead, indicating excellent welding quality.

[0087] Comparative Example 1.

[0088] Ultrasonic welding was completed in the same manner as in Example 1, except that seven pre-welding cathodes were prepared, each having a cathode tab (W1 / W2=1) with a width (W1) of the end portion of about 6 mm and a width (W2) of the connection portion connecting the end portion and the main body of about 6 mm.

[0089] After welding was completed, the width (W1') of the outermost cathode end was approximately 7.5 mm, and all cathodes were beyond the outer boundary of the metal lead.

[0090]

[0091] The negative electrode (200) for a lithium metal battery and the electrode assembly for a lithium metal battery according to an example 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 (200) for a lithium metal battery and the electrode assembly for a lithium metal battery according to an example of the present application can be applied to eco-friendly electric vehicles or hybrid vehicles to prevent climate change by suppressing air pollution and greenhouse gas emissions.

[0092] 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.

[0093] [Explanation of symbols]

[0094] 10... Electrode assembly for lithium metal battery

[0095] 100... metal lead

[0096] 200... Cathode for lithium metal battery

[0097] 200_1... first cathode

[0098] 200_2... Second cathode

[0099] 210... main body

[0100] 210_1... Main body of the first cathode

[0101] 210_2... Main body of the second cathode

[0102] 220... negative tab

[0103] 220_1... Cathode tab of the first cathode

[0104] 220_2... Cathode tab of the second cathode

[0105] 221... end

[0106] 221_1... End of the first cathode

[0107] 221_2... End of the second cathode

[0108] 222... connector

[0109] 222_1... Connection of the first cathode

[0110] 222_2... Connection of the second cathode

[0111] 300... insulating film

Claims

1. Main body and A negative tab extending from one edge of the main body and connected to a metal lead and including lithium metal, A negative electrode for a lithium metal battery, wherein the negative tab is configured such that the width (W1) of the end portion and the width (W2) of the connecting portion connecting the end portion and the main body portion are different.

2. In paragraph 1, A negative electrode for a lithium metal battery, wherein the width of the end portion (W1) is narrower than the width of the connection portion (W2).

3. In paragraph 2, A negative electrode for a lithium metal battery, wherein the ratio (W1 / W2) of the width of the end portion (W1) and the width of the connection portion (W2) is in the range of 0.1 to 0.

6.

4. In paragraph 2, The above negative electrode tab has a shape in which the width gradually decreases in a direction away from the main body.

5. A negative electrode for a lithium metal battery having a main body and a negative electrode tab extending from one edge of the main body and including lithium metal; and comprising a metal lead connected to the negative tab; The connection area (A) where the above metal lead and the negative tab are connected C ) is an electrode assembly for a lithium metal battery that does not extend beyond the outer boundary of the metal lead.

6. In paragraph 5, The above negative tab is joined to the metal lead by welding, An electrode assembly for a lithium metal battery, wherein the negative tab before being joined by the welding is configured such that the width (W1) of the end portion is narrower than the width (W2) of the connecting portion connecting the end portion and the main body portion.

7. In paragraph 6, In the negative tab after joining by the above welding, the width (W1') of the end portion is equal to the width (W) of the metal lead at a position corresponding to the end portion. L ) An electrode assembly for a lithium metal battery having a size equal to or less than that of the battery.

8. In paragraph 7, The width of the above end (W1') and the width of the metal lead (W L ) ratio (W1' / W L ) is an electrode assembly for a lithium metal battery having a range of 0.5 to 1.

9. In paragraph 5, The connection area (A) for the area (A2) of the above negative tab C ) An electrode assembly for a lithium metal battery having an area (A1) of 50% or more.

10. A lithium metal battery comprising a cathode and a metal lead, the cathode including a first cathode and a second cathode and having a plurality of cathodes having a structure laminated one by one, The above plurality of cathodes each include a main body and a cathode tab extending from one edge of the main body and including lithium metal, The first cathode is positioned so that the cathode tab is in direct contact with the metal lead and connected thereto, and the second cathode is positioned at the outermost portion of the laminated structure and does not make direct contact with the metal lead. A connection area (A) where the above metal lead and the negative tab of the first cathode are connected C ) is an electrode assembly for a lithium metal battery that does not extend beyond the outer boundary of the metal lead.

11. In Article 10, The negative tab of the above first cathode is joined to the metal lead by welding, The above multiple cathodes are joined by welding to form a laminated structure, The cathode tab of the first cathode before joining by the above welding has a width (W) at the end 11 ) is the width (W) of the connecting portion connecting the end portion and the main body. 12 ) is configured to be narrower than the second cathode, and the cathode tab of the second cathode has a width (W) of the end portion. 21 ) is the width (W) of the connecting portion connecting the end portion and the main body. 22 ) An electrode assembly for a lithium metal battery configured to be narrower than the diameter of the electrode assembly.

12. In paragraph 10, The above plurality of cathodes are welded together so that the ends of each cathode tab coincide, thereby forming a laminated structure. Each of the above bonded areas between the cathodes (A) J ) is projected perpendicularly to the surface where the metal lead is located, forming a corresponding area (A). E ) is an electrode assembly for a lithium metal battery that does not extend beyond the outer boundary of the metal lead.

13. In paragraph 12, The width (W) of the end of the cathode tab of the first cathode before joining by the above welding 11 ) is the width (W) of the end of the cathode tab of the second cathode. 21 ) An electrode assembly for a lithium metal battery having a size equal to or wider than that of the battery.

14. In paragraph 12, An electrode assembly for a lithium metal battery, wherein the width (W1) of the end of each cathode tab of the plurality of cathodes before being joined by the welding gradually increases from the second cathode to the first cathode.

15. In paragraph 12, The width (W) of the end of the cathode tab of the first cathode after joining by the above welding 11 ') and the width (W) of the end of the cathode tab of the second cathode 21 ') is the width (W) of the metal lead at a position corresponding to the end of the cathode tab of the first cathode. L ) An electrode assembly for a lithium metal battery having a size equal to or less than that of the battery.

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