Tab with improved welding performance

Abstract

Embodiments of the present invention provide a tab comprising: a metal substrate comprising aluminum; the metal layers are arranged on the two sides of the metal substrate; wherein the metal layer comprises 70 wt% to 99.9 wt% chromium, and wherein the tab has an ultrasonic weld strength of 70 kgf / mm2 or more.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2024-0114645, filed on August 26, 2024, which is incorporated herein by reference in its entirety. Technical Field

[0003] This invention relates to a lead tab with improved welding performance. Background Technology

[0004] As a core component of IT equipment, the secondary battery industry has received as much attention as semiconductors and displays. Recently, its use has been increasing in electric bicycles, hybrid electric vehicles (HEVs), electric vehicles (EVs), plug-in hybrid electric vehicles (PHEVs), and energy storage systems (ESS) that use large-capacity batteries.

[0005] A typical secondary battery has tabs for drawing electricity to the outside. In a secondary battery, one end of the tab is connected to the battery element and pressed against the opposite membrane, while the other end protrudes outside the membrane.

[0006] If a physical force is applied to a secondary battery, the bond strength between the tabs and the electrode tabs will weaken, leading to partial or complete breakage. In this state, if a large current flows through the battery in a short period, there is a risk of fire or explosion as the battery temperature rises.

[0007] To address these issues, research on electrode tabs with improved welding performance is ongoing. Summary of the Invention

[0008] The present invention relates to a tab with improved welding performance, which can prevent problems caused by the limitations and disadvantages of the aforementioned related technologies.

[0009] One embodiment of the present invention provides an electrode tab comprising: a metal substrate containing aluminum; and metal layers disposed on both sides of the metal substrate; wherein the metal layers contain 70 wt% to 99.9 wt% chromium, and wherein the electrode tab has a strength of 70 kgf / mm². 2 Or greater ultrasonic welding strength. Attached Figure Description

[0010] The above and other objects, features and advantages of this disclosure will become clearer from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0011] Figure 1This is a perspective view of a secondary battery according to an embodiment of the present invention.

[0012] Figure 2 This is a cross-sectional view of a tab according to an embodiment of the present invention.

[0013] Figure 3 It is along Figure 1 The cross-sectional view taken from line I-I'.

[0014] Figure 4 This is a conceptual diagram illustrating a portion of a sputtering device. Detailed Implementation

[0015] In the following description, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, the following embodiments are merely illustrative for the purpose of clarifying the present disclosure and do not limit the scope of the disclosure.

[0016] The shapes, dimensions, proportions, angles, quantities, etc., disclosed in the accompanying drawings for describing embodiments of this disclosure are illustrative, and therefore this disclosure is not limited to the details shown in the drawings. Throughout the specification, identical components may be denoted by the same reference numerals. In describing this disclosure, detailed descriptions of related known technologies are omitted if it is determined that such descriptions would unnecessarily obscure the main points of this disclosure.

[0017] When terms such as "comprising," "having," or "consisting of" are used in the description of this specification, other parts may be added unless the term "only" is used herein. When a component is described in the singular, the plural form is included unless otherwise stated. Furthermore, in interpreting components, even if not explicitly stated, they are interpreted as including a range of tolerances.

[0018] When describing positional relationships, for example, when the positional relationship between two parts is described as "on top", "above", "below", "adjacent to", etc., one or more other parts may exist between the two parts unless "right next to" or "directly" is used.

[0019] For ease of description, spatial relative terms such as "below," "below," "lower," "above," and "higher" are used herein to describe the relationship of one element or component shown in the accompanying drawings to other elements or components. It should be understood that spatial relative terms are intended to encompass different orientations of an element in use or operation, in addition to those shown in the accompanying drawings. For example, when an element in the accompanying drawings is flipped, an element described as "above" or "higher" relative to another element will be "below" or "lower" relative to that other element. Therefore, the exemplary term "below" can include both "above" and "below" orientations. Similarly, the exemplary terms "above" or "higher" can include both "above" and "below" orientations.

[0020] When describing temporal relationships, such as when the temporal relationship is described as "after", "following", "continuing on", "before", etc., non-continuous cases may also be included unless "immediately next to" or "directly" is used.

[0021] In describing various components, terms such as "first" and "second" are used, but these components are not limited by these terms. These terms are only used to distinguish one component from another. Therefore, within the scope of the technical spirit of this disclosure, the first component described below may also be the second component.

[0022] The term "at least one" should be understood to include all possible combinations of one or more related items. For example, "at least one of the first, second, and third items" could mean all combinations of two or more items from the first, second, and third items, as well as each of the first, second, and third items.

[0023] Features of the various embodiments of this disclosure may be connected or combined with each other in part or in whole, may be associated or operated by various technical means, and each embodiment may be implemented independently of each other or may be implemented together in a related relationship.

[0024] Figure 1 This is a perspective view of a secondary battery 1 according to an embodiment of the present invention.

[0025] Figure 2 This is a cross-sectional view of the tab 10 according to an embodiment of the present invention.

[0026] Figure 3 It is along Figure 1 The cross-sectional view taken from line I-I'.

[0027] There is no particular limitation on the type of secondary battery 1 according to an embodiment of the present invention, but a lithium secondary battery is preferred.

[0028] refer to Figure 1 and Figure 3According to one embodiment of the present invention, a secondary battery 1 is configured such that a film-shaped negative electrode 161 and a film-shaped positive electrode 162 are arranged to overlap each other via a separator 163, and an electrolyte 164 is disposed between the negative electrode 161 and the positive electrode 162 to enable charging and discharging by the migration of lithium ions. The secondary battery 1, comprising the negative electrode 161, the positive electrode 162, and the electrolyte 164, is enclosed in a liquid-tight state by a housing 30. Specifically, the negative electrode 161, the positive electrode 162, and the electrolyte 164 are sealed within the housing 30 to protect them from external influences. Furthermore, the negative electrode 161 is formed in a structure in which a secondary battery copper foil serves as a negative electrode current collector and is coated thereon with a negative electrode active material slurry. Similarly, the positive electrode 162 is formed in a structure in which a positive electrode active material slurry is coated on a positive electrode current collector (such as aluminum).

[0029] Furthermore, although not shown in the figure, the tab 10 can consist of a negative tab and a positive tab. More specifically, it is set in... Figure 1 The tab 10 on the left can be a positive tab, and the tab 10 on the right can be a negative tab.

[0030] Reference Figure 1 A sealing strip 20 is provided on one side of the casing 30 of the secondary battery 1. The sealing strip 20 is designed to further improve the adhesion between the tab 10 and the casing 30. The sealing strip 20 is disposed on the tab 10, and a portion of the sealing strip 20 is in close contact with the inner surface of the casing 30 to seal the casing 30. The sealing strip 20 has the function of preventing leakage of liquids (such as electrolyte 164) sealed inside the casing 30. In addition, the sealing strip 20 is disposed between the tab 10 and the casing 30 to ensure insulation between the tab 10 and the casing 30. A polypropylene film is used as the sealing strip 20. However, one embodiment of the invention is not limited to this and may be formed from a polymer-based composite material.

[0031] Reference Figure 1 One end of the tab 10 is connected to one of the positive electrode 161 and the negative electrode 162, and the other end of the tab 10 is exposed to the outside of the housing 30.

[0032] like Figure 2 As shown, the tab 10 of the present invention includes a metal substrate 110 and a metal layer 120 located on the metal substrate 110, the metal substrate comprising aluminum (Al). The metal substrate 110 and the metal layer 120 are described in detail below.

[0033] Reference Figure 3 Multiple electrode pieces 150 protruding from the negative electrode 161 are integrally combined to form a pre-welded portion 151, and the tab 10 is electrically connected to the upper part of the pre-welded portion 151 by welding.

[0034] For example, in the case of ultrasonic welding as a welding method, when ultrasonic vibration is applied, frictional heat causes plastic deformation, allowing the tab 10 to penetrate and adhere tightly to the pre-welded portion 151 formed by the integral bonding of multiple electrode sheets 150.

[0035] There are no particular restrictions on the material of the metal substrate 110, but it can be formed of aluminum or copper. According to one embodiment of the invention, the metal substrate 110 can be formed of aluminum.

[0036] According to one embodiment of the present invention, the metal substrate 110 may have a thickness of 100 μm to 1000 μm. Preferably, the metal substrate may have a thickness of 100 μm to 500 μm.

[0037] According to one embodiment of the present invention, the tab 10 may further include a metal layer 120 located on a metal substrate 110.

[0038] The metal layer 120 contains 70.0 wt% to 99.9 wt% (w / w) of chromium (Cr).

[0039] Specifically, the metal layer 120 can be formed by a dry vacuum process. For example, the metal layer 120 can be formed by any of the sputtering process, evaporation process, ion plating process, and CVD (chemical vapor deposition) process, which are examples of dry vacuum processes. Preferably, the metal layer 120 can be formed by a sputtering process.

[0040] Typically, the tabs also include a protective layer containing chromium compounds to improve corrosion resistance. This protective layer is formed through chromate treatment (chromate passivation, chromium plating, chromium diffusion). However, the protective layer formed by chromate treatment may have a very high oxygen fraction. Here, oxygen fraction refers to the ratio of oxygen atoms to the total number of atoms in the protective layer. A protective layer with a very high oxygen fraction can lead to excessive oxidation of the metal layer in contact with the protective layer, thereby reducing the adhesion between the tab and the insulating film, and potentially deteriorating the welding performance between the tab and the electrode sheet, thus weakening the bond strength at the weld area between the tab and the electrode sheet. This could lead to partial or complete breakage of the weld area. In this state, if a large current flows through it for a short period, there is a risk of fire or explosion as the battery heats up.

[0041] Furthermore, when a protective layer is formed through chromate treatment, some trivalent chromium (Cr) may be present within the protective layer. 3+ ) or hexavalent chromium (Cr 6+ At this point, hexavalent chromium (Cr) present within the protective layer... 6+It may have strong oxidizing capabilities. As a result, the metal layer in contact with the protective layer may be over-oxidized, which may reduce the adhesion between the tab and the insulating film, and the welding performance between the tab and the electrode sheet may deteriorate, which may weaken the bond strength of the welded area between the tab and the electrode sheet.

[0042] Therefore, according to one embodiment of the present invention, in order to increase the adhesion between the tab 10 and the sealing strip 20 and improve the welding performance between the tab 10 and the electrode sheet 150, the metal layer 120 needs to contain 70.0 wt% to 99.9 wt% chromium (Cr).

[0043] According to one embodiment of the invention, when the metal layer 120 is deposited by sputtering and contains 70.0 wt% to 99.9 wt% chromium (Cr), the oxygen fraction in the metal layer 120 is sufficiently reduced to achieve this purpose, thereby increasing the adhesion between the tab 10 and the sealing strip 20 and improving the welding performance between the tab 10 and the electrode sheet 150.

[0044] Furthermore, according to one embodiment of the present invention, when the metal layer 120 is deposited by a sputtering process and contains 70.0 to 99.9 wt% (w / w) of chromium (Cr), hexavalent chromium (Cr) 6+ The influence of the metal layer 120 is reduced, thereby suppressing human poisoning and environmental problems.

[0045] According to an embodiment of the present invention, the tab 10 can have a strength of 70 kgf / mm². 2 Or a greater ultrasonic welding strength. The ultrasonic welding strength of the electrode 10 is measured by welding the electrode 10 to 30 pre-welded aluminum foils, then holding the welded electrode 10 and the 30 pre-welded aluminum foils in a clamp, and then measuring the tensile strength. Here, the ultrasonic welding strength refers to the measured tensile strength. The method for measuring ultrasonic welding strength according to an embodiment of the present invention is described in detail below.

[0046] According to one embodiment of the present invention, when the tab 10 has 70 kgf / mm 2 With higher ultrasonic welding strength, the bonding strength of the welded area between the tab and the electrode sheet is improved, thereby suppressing or preventing partial or complete weld area fracture. Furthermore, even with a large current flow for a short period, the risk of fire or explosion is reduced in this state. Preferably, the tab 10 can have a strength of 80 kgf / mm². 2 Or greater ultrasonic welding strength.

[0047] On the other hand, if the electrode 10 has a strength of less than 70 kgf / mm 2If the ultrasonic welding strength is insufficient, the bonding strength at the welding area between the tab and the electrode sheet will decrease, leading to partial or complete breakage of the welding area. Furthermore, if a large amount of current flows through the battery in this state for a short period of time, there may be a risk of fire or explosion as the battery heats up.

[0048] According to one embodiment of the present invention, the metal layer 120 may have a thickness of 10 nm to 500 nm.

[0049] When the metal layer 120 has a thickness of less than 10 nm, the metal layer 120 may be deposited unevenly. As a result, when the secondary battery 1 is formed, the sealing strip 20 disposed on the metal layer 120 may be deposited unevenly, which may lead to the problem of leakage of electrolyte 164 inside the secondary battery 1.

[0050] Furthermore, when the thickness of the metal layer 120 exceeds 500 nm, the internal stress within the metal layer 120 increases, leading to cracking problems. Therefore, according to embodiments of the present invention, the metal layer 120 needs to have a thickness of 10 nm to 500 nm. Preferably, the metal layer 120 can have a thickness of 10 nm to 200 nm.

[0051] The following describes in detail a method for manufacturing tab 10 according to an embodiment of the present invention.

[0052] First, a metal substrate 110 is prepared.

[0053] The metal substrate 110 can have a thickness of 100 μm to 1000 μm, and although the material is not particularly limited, it can be formed of aluminum or copper. According to one embodiment of the invention, the metal substrate 110 can be aluminum.

[0054] Next, a metal layer 120 can be formed on the metal substrate 110 using a DC sputtering apparatus via a sputtering process. The metal layer 120 can have a thickness of 10 nm to 500 nm.

[0055] At this time, chromium (Cr) metal is used as a sputtering target.

[0056] Figure 4 This is a conceptual diagram schematically showing a portion of the sputtering device 40.

[0057] According to one embodiment of the present invention, a metal layer 120 is formed on a metal substrate 110 using a process employing a sputtering apparatus 40.

[0058] According to one embodiment of the present invention, the sputtering apparatus 40 may be provided with a chamber 13. A gas injection unit 11 may be provided on one side of the chamber 13, and a gas emission unit 12 may be provided on the other side of the chamber 13.

[0059] On this point, Figure 4 The illustration shows a configuration where the gas injection unit 11 is located on the left side of the chamber 13 and the gas emission unit 12 is located on the right side of the chamber 13. However, one embodiment of the invention is not limited to this configuration, and both the gas injection unit 11 and the gas emission unit 12 may be located on the lower side of the chamber 13.

[0060] Gas injection unit 11 provides a path for injecting sputtering gas from the outside of chamber 13 into the interior of chamber 13. Here, sputtering gas corresponds to gas, and specifically refers to the gas used to generate plasma in the sputtering process. The sputtering gas is injected into the interior of chamber 13 through gas injection unit 11 and can be ionized by a voltage applied inside chamber 13 to become electrons, ions (e.g., Ar), etc. + A plasma state consisting of a mixture of ions and a neutral gas. In one embodiment, the sputtering gas may be a mixture of argon and nitrogen, or it may be oxygen or nitrogen dioxide (NO2).

[0061] Although Figure 4 Although not shown, the gas injection unit 11 can be connected to a gas flow control device (not shown), a gas storage device (not shown), etc., located outside the chamber 13. Gas stored in the gas storage device can be injected into the chamber 13 through the gas injection unit 11 in an amount controlled by the gas flow rate control device.

[0062] The gas discharge unit 12 is used to pump air from inside chamber 13 to the outside to maintain a vacuum inside chamber 13. Although in Figure 4 The gas discharge unit 12 is connected to a vacuum pump (not shown) to control the amount of air discharged from inside chamber 13 to the outside.

[0063] Inside chamber 13, there are a base support 23, a base G located on the base support 23, a heating component 22, a target material 34, a target material support 31, and a control unit 33.

[0064] A substrate support 23 is disposed at the lower part of the chamber 13 for fixing the substrate G introduced into the chamber 13. Furthermore, a heating member 22 may be disposed inside the substrate support 23 to heat the substrate G fixed to the substrate support 23 to a predetermined temperature. The heating member 22 applies a predetermined amount of heat to the substrate G fixed to the substrate support 23 to enhance the reactivity with the deposited material deposited on the substrate G.

[0065] According to one embodiment of the present invention, the substrate G on the substrate support 23 is a metal substrate 110.

[0066] A target 34, made of deposition material, to be deposited on the upper surface of the substrate G, is disposed on the upper part of the substrate support 23, and the target 34 is fixed to the upper inner wall of the chamber 13 by the target support 31. A power supply 32 for applying voltage to the target 34 is connected to one side of the target 34, and the substrate support 31 is grounded. In addition, a magnet (not shown) may be disposed on the rear surface of the target 34, and the magnet is used to confine the electrons formed in the chamber 13 to the vicinity of the target 34.

[0067] When a negative charge is applied to the target 34, it reacts with the sputtering gas (such as argon (Ar)) injected into the chamber 13, causing the sputtering gas to ionize, and the ionized sputtering gas collides with the target 34. Here, the sputtering gas ionized by the magnet disposed on the rear surface of the target 34 continuously collides with the target 34, and the deposited material separated from the target 34 is thus accelerated toward the substrate G and deposited on the upper surface of the substrate G.

[0068] Next, the evaporated deposited material sprayed into chamber 13 moves toward substrate G, causing a uniform metal layer 120 to be deposited on substrate G.

[0069] According to one embodiment of the present invention, the target 34 disposed on the target support 31 is chromium (Cr).

[0070] A control unit 33 is provided on the upper left side of chamber 13. The pretreatment current, pretreatment pressure, pretreatment power and film formation pressure are controlled by the control unit 33.

[0071] According to an embodiment of the present invention, the sputtering voltage refers to the voltage at the power supply unit 32.

[0072] The present invention will now be described in detail through embodiments and comparative examples. However, the following embodiments are intended only to aid in understanding the present invention, and the scope of the present invention is not limited to these embodiments.

[0073] Example 1

[0074] After preparing a metal substrate made of aluminum, a tab with a thickness of 300 μm was fabricated by forming a 20 nm thick metal layer on the substrate using a sputtering process. Chromium (Cr) metal was used as the target material in the sputtering process, and the sputtering voltages are shown in Table 1 below.

[0075] Example 2

[0076] The tabs are manufactured using the same method as in Example 1, except for the conditions of the sputtering voltage used to form the metal layer.

[0077] Example 3

[0078] The tabs are manufactured using the same method as in Example 1, except for the conditions of the sputtering voltage used to form the metal layer.

[0079] Example 4

[0080] The tabs are manufactured using the same method as in Example 1, except for the conditions of the sputtering voltage used to form the metal layer.

[0081] Example 5

[0082] The tabs are manufactured using the same method as in Example 1, except for the conditions of the sputtering voltage used to form the metal layer.

[0083] Comparison Example 1

[0084] The tabs with a thickness of 300 μm were fabricated using the same method as in Example 1, except that a 20 nm thick protective layer was formed. This protective layer was formed by immersing an aluminum metal substrate in a 0.06 M chromate solution at room temperature for 20 seconds, drying it at room temperature for 10 seconds, rinsing it with distilled water for 10 seconds, immersing it again in a 0.06 M chromate solution at room temperature for 10 seconds, drying it again at room temperature for 10 seconds, rinsing it with distilled water for 10 seconds, and then drying it for 15 seconds.

[0085] Comparison Example 2

[0086] The tabs were fabricated using the same method as in Comparative Example 1, except that a 20 nm thick protective layer was formed. This protective layer was formed by immersing the metal substrate in a 0.06 M chromate solution at room temperature for 15 seconds, drying it at room temperature for 10 seconds, rinsing it with distilled water for 10 seconds, immersing it again in a 0.06 M chromate solution at room temperature for 10 seconds, drying it at room temperature for 10 seconds, rinsing it with distilled water for 10 seconds, and then drying it for 15 seconds.

[0087] Comparison Example 3

[0088] The tabs were fabricated using the same method as in Comparative Example 1, except that a 20 nm thick protective layer was formed. This protective layer was formed by immersing the metal substrate in a 0.06 M chromate solution at room temperature for 20 seconds, drying it at room temperature for 15 seconds, rinsing it with distilled water for 10 seconds, immersing it again in a 0.06 M chromate solution at room temperature for 10 seconds, drying it at room temperature for 10 seconds, rinsing it with distilled water for 10 seconds, and then drying it for 15 seconds.

[0089] Comparison Example 4

[0090] The tabs were fabricated using the same method as in Comparative Example 1, except that a 20 nm thick protective layer was formed. This protective layer was formed by immersing the metal substrate in a 0.06 M chromate solution at room temperature for 20 seconds, drying it at room temperature for 10 seconds, rinsing it with distilled water for 10 seconds, immersing it again in a 0.06 M chromate solution at room temperature for 20 seconds, drying it at room temperature for 10 seconds, rinsing it with distilled water for 10 seconds, and then drying it for 15 seconds.

[0091] Comparison Example 5

[0092] The tabs were fabricated using the same method as in Comparative Example 1, except that a 20 nm thick protective layer was formed. This protective layer was formed by immersing the metal substrate in a 0.06 M chromate solution at room temperature for 20 seconds, drying it at room temperature for 10 seconds, rinsing it with distilled water for 10 seconds, immersing it again in a 0.06 M chromate solution at room temperature for 10 seconds, drying it at room temperature for 5 seconds, rinsing it with distilled water for 10 seconds, and then drying it for 15 seconds.

[0093] In Examples 1 to 5 and Comparative Examples 1 to 5 above, the ultrasonic welding strength of the tabs, depending on whether the metal layer is formed by a sputtering process, is shown in Table 1 below.

[0094] Table 1

[0095]

[0096] i) Ultrasonic welding strength measurement

[0097] The tab samples manufactured in Examples 1 to 5 and Comparative Examples 1 to 5 were ultrasonically welded to 30 pre-welded aluminum foils (second ultrasonic welding step), and then the tensile strength was measured.

[0098] At this time, the tab sample was cut into a size of 45mm × 43mm (width: 45mm, length: 43mm) from the tabs manufactured in Examples 1 to 5 and Comparative Examples 1 to 5, and formed to a thickness of 300μm.

[0099] Each of the 30 pre-welded aluminum foils is 50mm × 50mm in size (width: 50mm, length: 50mm) and 10μm thick. The 30 pre-welded aluminum foils are formed by overlapping the 30 aluminum (Al) foils and performing ultrasonic welding (first ultrasonic welding step).

[0100] <Conditions for the First Ultrasonic Welding Step>

[0101] Welding area: 45mm × 6mm area (width: 45mm, length: 6mm), specifically, the welding area is located on one side of the aluminum foil.

[0102] Welding energy: 400J

[0103] Ultrasonic welding machine: Tech-SONIC US-3620SLS

[0104] <Second Ultrasonic Welding Step Conditions>

[0105] Welding area: 30mm × 6mm area (width: 30mm, length: 6mm), specifically, the welding area is located on one side of 30 pre-welded aluminum foils.

[0106] Welding energy: 2400W

[0107] Ultrasonic welding machine: Tektronix US-3620SLS

[0108] <Tensile Strength Measurement Conditions>

[0109] Tensile strength was measured for welded tab samples and 30 pre-welded aluminum foils. Specifically, tensile strength was measured for samples of welded tabs and 30 pre-welded aluminum foils.

[0110] Tensile strength can be measured using the ORIENTAL™ Universal Testing Machine (UTM) OTT-00. The tab sample is fixed to the upper clamp, and 30 pre-welded aluminum foil sheets are fixed to the lower clamp of the UTM to assess tensile strength.

[0111] Angle: 180°

[0112] Peeling speed: 30mm / min

[0113] Referring to Table 1, the following results can be confirmed.

[0114] In the cases of the tabs in Examples 1 to 5, where a metal layer is formed on a metal substrate by a sputtering process, it can be seen that the ultrasonic welding strength is 70 kgf / mm². 2 Or larger.

[0115] On the other hand, in the case of the tabs in Comparative Examples 1 to 5, where a protective layer is formed on the metal substrate by chromate treatment instead of by sputtering, it can be seen that the ultrasonic welding strength is less than 70 kgf / mm. 2 .

[0116] In addition to the effects described above, other features and advantages of the present invention will be described below, or may be clearly understood by those skilled in the art from such description and explanation.

[0117] According to the present invention, electrode tabs with improved welding performance can be provided.

[0118] It will be apparent to those skilled in the art that this disclosure is not limited to the embodiments and drawings described above, and that various substitutions, modifications, and variations may be made in this disclosure without departing from its spirit or scope. Therefore, the scope of this disclosure is defined by the appended claims, and all variations or modifications derived from the meaning, scope, and equivalents of the claims are intended to fall within the scope of this disclosure.

Claims

1. A type of electrode, comprising: A metal substrate comprising aluminum; as well as Metal layers are disposed on both sides of the metal substrate; The metal layer contains 70 wt% to 99.9 wt% chromium, and The electrode tabs described herein have a strength of 70 kgf / mm. 2 Or greater ultrasonic welding strength.

2. The tab according to claim 1, wherein the metal substrate has a thickness of 100 μm to 1000 μm.

3. The tab according to claim 1, wherein the metal layer has a thickness of 10 nm to 500 nm.

4. The tab according to claim 1, wherein the metal layer is formed by a dry vacuum process.

5. The tab according to claim 4, wherein the dry vacuum process includes at least one of sputtering, evaporation, ion plating and CVD processes.

6. A secondary battery comprising the tabs according to claim 1.

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