Electrode lead and manufacturing method for the electrode lead

Abstract

The present invention relates to an electrode lead and a method for manufacturing an electrode lead, and more specifically, to an electrode lead connected to an electrode assembly of a secondary battery capable of repeated charging and discharging, and a method for manufacturing such an electrode lead. An electrode lead according to one embodiment of the present invention includes a first portion coupled to an electrode tab of an electrode assembly of a secondary battery and a second portion connected to the first portion and protruding outside the case of the secondary battery, wherein the first portion is formed to be narrower than the second portion, and a plating layer may be formed on at least a portion of the first portion and the second portion.

Description

Technology Field

[0001] The present invention relates to an electrode lead and a method for manufacturing an electrode lead, and more specifically, to an electrode lead connected to an electrode assembly of a rechargeable secondary battery and a method for manufacturing such an electrode lead. Background Technology

[0002] Unlike primary batteries, which cannot be recharged, rechargeable batteries are batteries that can be charged and discharged. Low-capacity rechargeable batteries are used in small portable electronic devices such as mobile phones, laptop computers, and camcorders, while high-capacity batteries are widely used as power sources for motors in hybrid vehicles and the like.

[0003] These secondary batteries can have various structures. For example, secondary batteries can be classified into coin batteries, cylindrical batteries, prismatic batteries, and pouch batteries depending on the shape of the battery case. In secondary batteries, the electrode assembly mounted inside the battery case consists of a laminated structure of electrodes and separators, and can convert electrical energy into chemical energy or vice versa.

[0004] The electrodes constituting the electrode assembly can be divided into a coated portion coated with an active material and an uncoated portion of the electrode. The uncoated portions of the electrode within the electrode assembly are welded together to form an electrode tab, and the electrode tab can be coupled to an electrode lead to be connected to an external device.

[0005] To improve battery efficiency, it is important to reduce the resistance of the electrode leads; however, conventional electrode leads have been designed in the shape of hexahedral rods with a width corresponding to the width of the electrode tab, which has posed physical limitations when designing fast-charging and high-output batteries. The problem to be solved

[0006] The present invention was devised in recognition of the above-mentioned problems, and the objective of the present invention is to provide an electrode lead with a structure capable of minimizing electrical resistance and a method for manufacturing such an electrode lead. means of solving the problem

[0007] An electrode lead according to the present invention is an electrode lead connected to an electrode assembly of a secondary battery, comprising: a first portion coupled to an electrode tab of the electrode assembly; and a second portion connected to the first portion and protruding outside the case of the secondary battery, wherein the first portion is formed to be narrower than the second portion, and a plating layer may be formed on at least a portion of the first portion and the second portion.

[0008] Each of the above first and second parts may have a three-layer structure stacked in the order of an aluminum layer, a copper layer, and an aluminum layer.

[0009] The plating layer may be formed on the surface of the first part where the copper layer is exposed and on the surface of the second part connected to the first part.

[0010] The thickness of the plurality of aluminum layers is the same, and the thickness of the aluminum layer and the copper layer may be 1:1 to 1:8.

[0011] The above plating layer may be composed of nickel material.

[0012] A lead film composed of an insulating material may be attached to the first part above.

[0013] The lead film above can cover the boundary area in contact with the second part of the first part.

[0014] The method for manufacturing an electrode lead according to the present invention is a method for manufacturing an electrode lead connected to an electrode assembly of a secondary battery, and may include: a notching step of forming a plurality of notching grooves on one side of a metal plate surface; a plating step of forming a plating layer on one side of the metal plate surface and on the plurality of notching grooves; and a cutting step of cutting the metal plate surface in a straight direction from the center of each of the plurality of notching grooves to the other side of the metal plate surface.

[0015] The above notching step may be characterized by including the step of forming a plurality of notching grooves on one side of a metal plate surface having a three-layer structure stacked in the order of an aluminum layer, a copper layer, and an aluminum layer.

[0016] The above notching step may include the step of forming a plurality of notching grooves at equal intervals on one side of the metal plate surface.

[0017] The plating step may be characterized by including the step of forming a plating layer on one side of the metal plate surface and on the surface where the copper layer is exposed among a plurality of notching grooves.

[0018] The plating step may include the step of forming a plating layer composed of a nickel material on one side of the metal plate surface and on a plurality of notching grooves.

[0019] Meanwhile, the above electrode lead manufacturing method is performed after the cutting step and may further include a film attachment step of attaching a lead film of an insulating material to the cut metal plate surface.

[0020] The above-described cut metal plate surface includes a first portion that is relatively narrow and a second portion that is connected to the first portion and is wider than the first portion, and the film attachment step may be a step of attaching the lead film to a boundary area in the first portion that is in contact with the second portion. Effects of the invention

[0021] An electrode lead according to one embodiment of the present invention includes a first portion coupled to an electrode tab of an electrode assembly and a second portion connected to the first portion and protruding outside the case of a secondary battery, wherein the first portion is formed to be narrower in width than the second portion, and a plating layer may be formed on at least a portion of the first portion. In this case, the cross-sectional area of ​​the portion of the electrode lead protruding outside the case of the secondary battery can be set to be large, thereby having the effect of lowering the electrical resistance of the electrode lead. Brief explanation of the drawing

[0022] FIG. 1 is a drawing for comparing the width lengths of a first part and a second part in an electrode lead according to the present invention. FIG. 2 is a drawing showing a plating layer formed on a first portion of an electrode lead according to the present invention. FIG. 3 is a drawing showing a lead film attached to a first portion of an electrode lead according to the present invention. FIG. 4 is a flowchart showing the steps of the electrode lead manufacturing method according to the present invention in sequence. FIG. 5 is a diagram illustrating the notching step in the electrode lead manufacturing method according to the present invention. FIG. 6 is a diagram illustrating the plating step in the electrode lead manufacturing method according to the present invention. FIG. 7 is a diagram illustrating the film attachment step in the electrode lead manufacturing method according to the present invention. Specific details for implementing the invention

[0023] Hereinafter, preferred embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited or restricted by the following embodiments.

[0024] In order to clearly explain the present invention, detailed descriptions of related prior art that are irrelevant to the explanation or that may unnecessarily obscure the essence of the invention have been omitted. Furthermore, when assigning reference numerals to the components of each drawing in this specification, identical or similar reference numerals are assigned to identical or similar components throughout the entire specification.

[0025] In addition, terms or words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0026] Hereinafter, an electrode lead and a method for manufacturing an electrode lead according to the present invention will be described with reference to the drawings.

[0027] electrode leads

[0028] FIG. 1 is a drawing for comparing the width lengths of a first portion and a second portion in an electrode lead according to the present invention. FIG. 2 is a drawing showing a plating layer formed in a first portion in an electrode lead according to the present invention.

[0029] Referring to FIGS. 1 and 2, the electrode lead (10) according to the present invention is an electrode lead (10) connected to an electrode assembly of a secondary battery, and may include a first part (100) coupled to an electrode tab of the electrode assembly and a second part (200) connected to the first part (100) and protruding outside the case of the secondary battery. At this time, the first part (100) is formed to be narrower in width than the second part (200), and a plating layer (300) may be formed on the first part (100). Specifically, the plating layer (300) may be formed only on at least a portion of the first part (100) and the second part (200). That is, the plating layer (300) may be formed on at least a portion of the first part (100) and / or at least a portion of the second part (200).

[0030] In the electrode lead (10) according to the present invention, the second portion (200), excluding the first portion (100) coupled to the electrode tab of the electrode assembly, may have a wider width than the first portion (100). At this time, the electrode lead (10) is provided with a second portion (200) having a relatively large cross-sectional area, so the average cross-sectional area of ​​the electrode lead (10) may also increase. Accordingly, the electrode lead (10) according to the present invention has a relatively low overall resistance value, so it may be suitable for rapid charging and high-output battery design.

[0031] Specifically, the first part (100) is a part that is welded to the electrode tab of the electrode assembly, and the first part (100) may have the same width as the electrode tab. On the other hand, the width of the second part (200) that is not welded to the electrode tab may not be constrained by the width of the electrode tab. The electrode lead (10) according to the present invention is characterized by increasing the width of the second part (200) to expand the cross-sectional area of ​​the second part (200). In this case, compared to designing the total width of the electrode lead to be the same as the width of the electrode tab, the average cross-sectional area of ​​the electrode lead (10) is increased, allowing the resistance value of the electrode lead (10) to be designed to be lower.

[0032] In addition, in the electrode lead (10) according to the present invention, the plating layer (300) is formed mainly on the first part (100) which is coupled to the electrode tab of the electrode assembly, thereby effectively preventing damage to the first part (100) which is inserted into the internal space of the case of the secondary battery. Specifically, an electrolyte is injected into the internal space of the case of the secondary battery, and the plating layer (300) is formed on the first part (100) to minimize or block contact between the copper region of the first part (100) and the electrolyte, thereby preventing or delaying oxidation of the first part (100) by the electrolyte.

[0033] Accordingly, since the plating layer (300) is formed on the first part (100), it has high durability, so the first part (100) may not be easily damaged even in an internal environment where the potential fluctuates due to the charging and discharging of the secondary battery.

[0034] The electrode assembly is a laminate comprising multiple electrodes and separators and can have various structures. For example, the electrode assembly can be a stack-type electrode assembly in which multiple electrodes and separators are alternately stacked. Additionally, the electrode assembly can be a stack-folding type electrode assembly in which multiple electrodes and separators are stacked in one direction and then folded, or a jelly roll type electrode assembly in which electrodes and separators are alternately stacked and then wound.

[0035] The electrode tab is formed or connected to each electrode included in the electrode assembly, and may include the electrode uncoated portion excluding the electrode coated portion coated with active material. Additionally, the electrode tab may be a conductor tab or sheet separately connected to the electrode.

[0036] The case of the secondary battery serves as an outer casing that encloses the aforementioned electrode assembly and electrode tab, and can be configured in various ways. For example, a rigid outer casing made of metal or non-metal may be used for the case of the secondary battery.

[0037] In addition, the case of the secondary battery may be a pouch-type outer material composed of a laminate sheet. Such a laminate sheet may include a metal layer such as aluminum or stainless steel. In this case, a resin layer may be formed on the outer surface and / or inner surface of the metal layer.

[0038] The metal layer can serve as a substrate that maintains mechanical strength and as a barrier layer that prevents the penetration of moisture and oxygen. In addition to preventing the ingress or leakage of foreign substances such as gas and moisture, the metal layer may be composed of aluminum or an aluminum alloy to improve the strength of the battery case. Aluminum alloys such as alloy numbers 8079, 1N30, 8021, 3003, 3004, 3005, 3104, and 3105 may be used, and these may be used individually or in combination of two or more.

[0039] The first resin layer coated on the outer surface of the metal layer must have excellent resistance to the external environment to protect the electrode assembly from the outside; therefore, the first resin layer requires excellent tensile strength and corrosion resistance relative to its thickness. For such a first resin layer, polyester-based resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), and polyolefin-based resins such as polyethylene and polypropylene may be used.

[0040] The second resin layer coated on the inner surface of the metal layer can be bonded together to seal the internal space of the case of the secondary battery, and the second resin layer can be composed of a polyolefin-based resin. For example, the second resin layer may use CPP (Casted Polypropylene), chlorinated polypropylene, polyethylene, ethylene-propylene copolymer, polyethylene-acrylic acid copolymer, and polypropylene-acrylic acid copolymer.

[0041] Meanwhile, the electrode lead (10) according to the present invention is coupled to the aforementioned electrode tab to connect the electrode assembly and an external device, and at least a portion of the electrode lead (10) may be exposed outside the case of the secondary battery. Such electrode lead (10) is composed of a conductor through which current flows, and the lower the resistance value of the electrode lead (10), the higher the energy efficiency of the secondary battery may be.

[0042] The electrode lead (10) according to the present invention may be configured to have a structure having a low resistance value. Specifically, the electrode lead (10) may be configured to have a first part (100) coupled to an electrode tab and a second part (200) connected to the first part (100) and protruding outside the case of a secondary battery.

[0043] Here, the width (L1) of the first part (100) may be formed to be shorter than the width (L2) of the second part (200). In this case, the width (L1) of the part inserted inside the case of the secondary battery may be formed narrowly, and the width (L2) of the part inserted outside the case of the secondary battery may be formed relatively widely.

[0044] Considering the electrolyte injected into the internal space of the secondary battery case, it is better for the width (L1) of the part of the electrode lead (10) inserted into the secondary battery case to be formed narrower. However, if the overall width of the electrode lead (10) is formed narrowly, the electrode lead (10) will have a narrow cross-sectional area, which causes a problem of having a high resistance value.

[0045] In the case of the electrode lead (10) according to the present invention, the width (L1) of the portion inserted inside the case of the secondary battery is formed narrowly to improve the space utilization of the internal space of the secondary battery case, and at the same time, the width (L2) of the portion protruding outside the case of the secondary battery is formed wide to have an advantageous effect of forming a low resistance value of the electrode lead (10).

[0046] Meanwhile, the first part (100) and the second part (200) may have various structures. For example, the first part (100) and the second part (200) may have a laminated structure in which different types of conductors are stacked.

[0047] In the case of the first part (100), it may have a three-layer structure in which an aluminum layer (110), a copper layer (120), and an aluminum layer (130) are stacked. Also, in the case of the second part (200), it may have a three-layer structure in which an aluminum layer (210), a copper layer (220), and an aluminum layer (230) are stacked. In this way, since copper layers (120, 220) with low electrical resistance are included in each of the first part (100) and the second part (200) constituting the electrode lead (10), the electrical resistance value of the electrode lead (10) can be reduced compared to the case where the entire electrode lead (10) is composed only of aluminum layers with relatively high electrical resistance.

[0048] At this time, the aluminum layer (110) which is the lowest layer of the first part (100) and the aluminum layer (210) which is the lowest layer of the second part (200) may have the same thickness. Likewise, the copper layer (120) included in the first part (100) and the copper layer (220) included in the second part (200) may have the same thickness. In addition, the aluminum layer (130) which is the uppermost layer of the first part (100) and the aluminum layer (230) which is the uppermost layer of the second part (200) may have the same thickness.

[0049] Specifically, in the case of the first part (100), the plurality of aluminum layers (110, 130) forming it may have substantially the same thickness. Additionally, the thickness of the aluminum layer (110) and the copper layer (120) may form a ratio of 1:1 to 1:8. In this case, by making the thickness of the copper layer (120), which has relatively low resistance, thicker, there is an advantageous effect of lowering the resistance value of the first part (100).

[0050] Additionally, in the case of the second part (200), the plurality of aluminum layers (210, 230) forming it may have substantially the same thickness. Also, the thickness of the aluminum layer (210) and the copper layer (220) may form a ratio of 1:1 to 1:8. In this case, by making the thickness of the copper layer (220), which has relatively low resistance, thicker, there is an advantageous effect of lowering the resistance value of the second part (200).

[0051] Meanwhile, a plating layer (300) may be formed on a first part (100) of the electrode lead (10) that is inserted into the case of the secondary battery. The plating layer (300) may be formed of a metal with low reactivity to protect the first part (100) from the electrolyte injected into the internal space of the secondary battery case.

[0052] In particular, since the first part (100) has a copper layer (120) composed of a highly reactive copper material, the plating layer (300) can be formed on the surface of the first part (100) where the copper layer (120) is exposed. In this case, there is an advantageous effect of preventing the copper layer (120) from oxidizing by blocking the highly reactive copper layer (120) from coming into contact with the electrolyte inside the case of the secondary battery.

[0053] Additionally, the plating layer (300) may be formed only on the surface of the first part (100) where the copper layer (120) is exposed, and the plating layer (300) may not be formed on the surface where the copper layer (120) is not exposed. Specifically, the first part (100) has a multilayer hexahedral structure in which an aluminum layer (110), a copper layer (120), and an aluminum layer (130) are sequentially stacked, and one side of the first part (100) may be connected to the second part (200). At this time, the copper layer (120) is exposed on three side walls of the first part (100), and the metal layer (300) may be formed only on the three side walls of the first part (100) where the copper layer (120) is exposed. In this case, there is an advantageous effect of minimizing the use of metal material used to form the plating layer (300) while simultaneously completely blocking the exposure of the copper layer (120).

[0054] The plating layer (300) is composed of a metal with low reactivity, and various materials may be used. For example, the plating layer (300) may be composed of a nickel (Ni) material with low reactivity. In this case, the copper layer (120) can be effectively prevented from being oxidized by the electrolyte.

[0055] Meanwhile, the plating layer (300) may also be formed on the surface of the first part (100) protruding from the second part (200). Specifically, the plating layer (300) may be formed only on the surface of the second part (200) where the copper layer (220) is exposed, and may be formed only on the surface of the first part (100) protruding therefrom. In this case, the copper layer (220) of the second part (200) may be prevented from coming into contact with the electrolyte inside the case of the secondary battery, thereby preventing the copper layer (220) from oxidizing.

[0056] Additionally, although not illustrated in FIG. 2, the plating layer (300) may be formed only on the first part (100) among the first part (100) and the second part (200). In this case, the plating layer (300) is formed only on the surface of the first part (100) where the copper layer (120) is exposed, and the plating layer (300) may not be formed on the surface of the first part (100) where the copper layer (120) is not exposed.

[0057] FIG. 3 is a drawing showing a lead film attached to a first portion of an electrode lead according to the present invention.

[0058] Referring to FIG. 3, a lead film (400) made of an insulating material may be attached to a first part (100) constituting the electrode lead (10). The lead film (400) is adhered to the electrode lead (10) so that when the electrode lead (10) is subsequently inserted into a battery case, an insulating state can be maintained between the electrode lead (10) and the battery case.

[0059] These lead films (400) can be attached to the electrode lead (10) in various ways. For example, the lead film (400) may be an insulating tape with an adhesive layer formed on one side, and may be attached to the electrode lead (10) such that the adhesive layer faces the electrode lead (10).

[0060] Additionally, as illustrated in FIG. 3, the lead film (400) can cover a boundary area that is in contact with the second part (200) of the first part (100). At this time, since the second part (200), which is relatively wide, is located outside the boundary area, the lead film (400) can be prevented from moving outward by the second part (200). In this case, there is an advantageous effect of preventing the position of the lead film (400) from changing even during repeated charging and discharging of the electrode assembly included in the electrode lead (10).

[0061] Method for manufacturing electrode leads

[0062] FIG. 4 is a flowchart sequentially illustrating the steps of a method for manufacturing an electrode lead according to the present invention. FIG. 5 is a diagram illustrating the notching step in the method for manufacturing an electrode lead according to the present invention. FIG. 6 is a diagram illustrating the plating step in the method for manufacturing an electrode lead according to the present invention.

[0063] Referring to FIGS. 4 to 6, the method for manufacturing an electrode lead according to the present invention is a method for manufacturing an electrode lead (10) connected to an electrode assembly of a secondary battery, and may include a notching step (S10) of forming a plurality of notching grooves (540) on one side (501) of a metal plate surface (500), a plating step (S20) of forming a plating layer (550) on one side (501) of the metal plate surface (500) and on the plurality of notching grooves (540), and a cutting step (S30) of cutting the metal plate surface (500) in a straight direction (A1, A2, A3) from the center of each of the plurality of notching grooves (540) to the other side (502) of the metal plate surface (500).

[0064] According to this method of manufacturing an electrode lead, an electrode lead (10) can be manufactured in which the width of the portion inserted into the case of a secondary battery and coupled to the electrode tab of an electrode assembly is formed narrowly, and the width of the portion protruding outside the case of the secondary battery is formed relatively widely. In this case, forming the width of the portion inserted into the case of the secondary battery narrowly has the advantageous effect of improving the space utilization of the internal space of the secondary battery case. In addition, forming the width of the portion protruding outside the case of the secondary battery wide has the advantageous effect of forming a low resistance value of the electrode lead (10).

[0065] In the electrode lead (10) manufactured by the electrode lead manufacturing method according to the present invention, the second portion, excluding the first portion coupled to the electrode tab of the electrode assembly, may have a wider width than the first portion. At this time, since the electrode lead (10) has a second portion having a relatively large cross-sectional area, the average cross-sectional area of ​​the electrode lead (10) may also increase. Accordingly, the electrode lead (10) manufactured by the electrode lead manufacturing method according to the present invention has a relatively low overall resistance value, and thus may be suitable for rapid charging and high-output battery design.

[0066] Specifically, the first part is a portion welded to the electrode tab of the electrode assembly, and the first part may have the same width as the electrode tab. On the other hand, the width of the second part, which is not welded to the electrode tab, may not be constrained by the width of the electrode tab. The electrode lead (10) manufactured by the electrode lead manufacturing method according to the present invention is characterized by increasing the width of the second part to expand the cross-sectional area of ​​the second part (200). In this case, compared to designing the total width of the electrode lead to be the same as the width of the electrode tab, the average cross-sectional area of ​​the electrode lead (10) can be increased to design a lower overall resistance value.

[0067] Meanwhile, referring to FIG. 5, the aforementioned notching step (S10) may be a step of forming a plurality of notching grooves (540) on one side (501) of a metal plate surface (500) having a three-layer structure stacked in the order of an aluminum layer (510), a copper layer (520), and an aluminum layer (530). Here, the notching grooves (540) may be formed in various ways.

[0068] For example, the notching grooves (540) can be formed by an optical device such as a laser device. Additionally, the notching grooves (540) can be formed by a press device that physically presses one side (501) of the metal plate surface (500).

[0069] In the notching step (S10), a plurality of notching grooves (540) formed on one side (501) of the metal plate surface (500) may be formed in various order. For example, the plurality of notching grooves (540) may be formed sequentially along one direction, or the plurality of notching grooves (540) may be formed simultaneously.

[0070] The spacing between the plurality of notching grooves (540) formed in the notching step (S10) can be configured in various ways. For example, the spacing between the plurality of notching grooves (540) formed on one side (501) of the metal plate surface (500) can all have the same size.

[0071] Meanwhile, referring to FIG. 6, the aforementioned plating step (S20) may be a step of forming a plating layer (550) on one side (501) of the metal plate surface (500) and on the surface where the copper layer (520) is exposed among a plurality of notching grooves (540). This plating layer (550) may be composed of a metal with low reactivity.

[0072] When the metal plate surface (500) is processed into an electrode lead (10), the portion where the plating layer (550) is formed can correspond to the portion that is inserted into the case of the secondary battery and connected to the electrode tab of the electrode assembly. Since this plating layer (550) is formed from a metal with low reactivity, it can protect the electrode lead (10) from the electrolyte injected into the internal space of the secondary battery case. Specifically, the plating layer (550) can prevent or delay oxidation by the electrolyte of the portion of the electrode lead (10) that is inserted into the internal space of the secondary battery case.

[0073] In particular, a copper layer (520) composed of a highly reactive copper material exists on the metal plate surface (500), and a plating layer (550) can be formed on the metal plate surface (500) to block the exposure of this copper layer (520). After the metal plate surface (500) is processed into an electrode lead (10), the plating layer (550) can prevent the highly reactive copper layer (520) from coming into contact with the electrolyte inside the secondary battery case, thereby preventing the copper layer (520) from oxidizing. That is, the plating layer (550) is formed on the part of the metal plate surface (500) that is to be inserted into the case of the secondary battery after being processed into an electrode lead (10), thereby preventing the copper layer (520) in that part from being oxidized by the electrolyte.

[0074] Meanwhile, the aforementioned plating step (S20) may be a step of forming a plating layer (550) composed of a nickel material on one side (501) of the metal plate surface (500) and a plurality of notching grooves (540). In this case, the plating layer (550) is composed of a nickel (Ni) material with low reactivity, so that after the metal plate surface (500) is processed into an electrode lead (10), the copper layer (520) of the electrode lead (10) can be effectively prevented from being oxidized by the electrolyte inside the secondary battery case.

[0075] In the plating step (S20), the plating layer (550) composed of Ni material can be formed mainly on the portion of the metal plate surface (500) that is to be inserted into the case of the secondary battery after being processed into the electrode lead (10). That is, the plating layer (550) can be formed only on the surface of the metal plate surface (500) where the copper layer (520) is exposed.

[0076] The cutting step (S30) is a step of cutting the metal plate surface (500) in a straight direction (A1, A2, A3) from the center of each of the multiple notching grooves (540) to the other side (502) of the metal plate surface (500), and each of the cut metal plate surfaces (500) can become an electrode lead (10). In the cutting step (S30), the cutting of the metal plate surface (500) can be performed in various ways. For example, in the cutting step (S30), each of the cutting lines (A1, A2, A3) of the metal plate surface (500) can be cut simultaneously by cutting equipment such as a laser cutter.

[0077] FIG. 7 is a diagram illustrating the film attachment step in the electrode lead manufacturing method according to the present invention.

[0078] The electrode lead manufacturing method according to the present invention is performed after the cutting step (S30) and may further include a film attachment step (S40) in which a lead film (560) of an insulating material is attached to the cut metal plate surface (500). That is, the film attachment step (S40) may be a step of attaching a lead film (560) to each of the cut metal plate surfaces.

[0079] The lead film (400) is adhered to the electrode lead (10) so that when the electrode lead (10) is subsequently inserted into the battery case, it can maintain an insulating state between the electrode lead (10) and the battery case.

[0080] Meanwhile, in the film attachment step (S40), the lead film (560) can be attached to various locations on the cut metal plate surface (500). For example, the cut metal plate surface (500) may include a first part with a relatively narrow width (D1) and a second part connected to the first part and having a relatively wider width (D2) than the first part, and in the film attachment step (S40), the lead film (560) can be attached to the boundary area of ​​the first part that is in contact with the second part.

[0081] At this time, a second portion with a relatively wider width (D2) is located on the outer side of the aforementioned boundary region, so that the lead film (560) can be prevented from moving outward by the second portion. In this case, there is an advantageous effect of preventing the position of the lead film (560) from changing even during repeated charging and discharging of the electrode assembly included in the electrode lead (10).

[0082] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs. Explanation of the symbols

[0083] 10: Electrode Lead 100: First Part 110, 130: Aluminum layer 120: Copper layer 200: Part 2 210, 230: Aluminum layer 220: Copper layer 300: Plating layer 400: Lead film 500: Metal plate surface 510, 530: Aluminum layer 520: Copper layer 540: Notching groove 550: Plating layer S10: Notching step S20: Plating step S30: Cutting step S40: Film attachment step

Claims

Claim 1 An electrode lead connected to an electrode assembly of a secondary battery, comprising: a first portion coupled to an electrode tab of the electrode assembly; and a second portion connected to the first portion and protruding outside the case of the secondary battery, wherein the first portion is formed to be narrower in width than the second portion, and a plating layer is formed on at least a portion of the first portion and the second portion, wherein each of the first portion and the second portion has a three-layer structure stacked in the order of an aluminum layer, a copper layer, and an aluminum layer, and the plating layer is formed on the surface of the first portion where the copper layer is exposed and on the surface of the second portion connected to the first portion. Claim 2 delete Claim 3 delete Claim 4 An electrode lead according to claim 1, characterized in that the thickness of a plurality of aluminum layers is the same, and the thickness of the aluminum layer and the copper layer is 1:1 to 1:

8. Claim 5 An electrode lead according to claim 1, characterized in that the plating layer is composed of a nickel material. Claim 6 An electrode lead according to claim 1, characterized in that a lead film composed of an insulating material is attached to the first portion. Claim 7 An electrode lead according to claim 6, wherein the lead film covers a boundary region in contact with the second portion of the first portion. Claim 8 A method for manufacturing an electrode lead connected to an electrode assembly of a secondary battery, comprising: a notching step of forming a plurality of notching grooves on one side of a metal plate surface; a plating step of forming a plating layer on one side of the metal plate surface and on the plurality of notching grooves; and a cutting step of cutting the metal plate surface in a straight direction from the center of each of the plurality of notching grooves to the other side of the metal plate surface. Claim 9 A method for manufacturing an electrode lead according to claim 8, wherein the notching step comprises the step of forming a plurality of notching grooves on one side of a metal plate surface having a three-layer structure stacked in the order of an aluminum layer, a copper layer, and an aluminum layer. Claim 10 A method for manufacturing an electrode lead according to claim 8, wherein the notching step comprises forming a plurality of notching grooves at equal intervals on one side of the metal plate surface. Claim 11 A method for manufacturing an electrode lead according to claim 9, wherein the plating step comprises forming a plating layer on one side of the metal plate surface and on the surface where the copper layer is exposed among a plurality of notching grooves. Claim 12 A method for manufacturing an electrode lead according to claim 8, wherein the plating step comprises the step of forming a plating layer composed of a nickel material on one side of the metal plate surface and on a plurality of notching grooves. Claim 13 A method for manufacturing an electrode lead according to claim 8, further comprising a film attachment step performed after the cutting step, wherein a lead film of an insulating material is attached to the cut metal plate surface. Claim 14 A method for manufacturing an electrode lead according to claim 13, wherein the cut metal plate surface comprises a first portion having a relatively narrow width and a second portion connected to the first portion and having a wider width than the first portion, and the film attachment step is a step of attaching the lead film to a boundary area in the first portion that is in contact with the second portion.

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