Electrode lead and electrode lead manufacturing method

Abstract

The present invention relates to an electrode lead and an electrode lead manufacturing method, and more specifically, to: an electrode lead connected to an electrode assembly of a rechargeable battery which can be repeatedly charged and discharged; and an electrode lead manufacturing method for manufacturing the electrode lead. The electrode lead according to an embodiment of the present invention comprises: a first portion coupled to an electrode tab of an electrode assembly of a rechargeable battery; and a second portion connected to the first portion and protruding outward from a case of the rechargeable battery, wherein the first portion is narrower than the second portion, and a plating layer may be formed on at least part of the first portion and the second portion.

Description

Electrode leads and electrode lead manufacturing methods

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0114616, filed August 26, 2024, and Korean Patent Application No. 10-2025-0114036, filed August 18, 2025, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to an electrode lead and a method for manufacturing an electrode lead, and more particularly, to an electrode lead connected to an electrode assembly of a rechargeable secondary battery and a method for manufacturing such an electrode lead.

[0005] Secondary batteries (rechargeable batteries) are rechargeable and dischargeable, unlike primary batteries, which are non-rechargeable. Low-capacity secondary batteries are used in small, portable electronic devices such as cell phones, laptops, and camcorders, while high-capacity batteries are widely used as power sources for motors in hybrid vehicles and other vehicles.

[0006] These secondary batteries can have various structures. For example, depending on the shape of the battery case, secondary batteries can be classified into coin-shaped batteries, cylindrical batteries, square batteries, and pouch-shaped batteries. In secondary batteries, the electrode assembly mounted inside the battery case consists of a laminated structure of electrodes and a separator, and can convert electrical energy into chemical energy or vice versa.

[0007] The electrodes constituting the electrode assembly can be divided into a coated portion coated with an active material and an electrode uncoated portion not coated with an active material. The electrode uncoated portions within the electrode assembly are welded together to form electrode tabs, and the electrode tabs are connected to electrode leads so as to be connected to an external device.

[0008] In order to improve the efficiency of a battery, it is important to reduce the resistance of the electrode lead. However, conventional electrode leads are designed in the shape of a hexahedral rod with a width corresponding to the width of the electrode tab, which has been a physical limitation in the design of rapid charging and high-output batteries.

[0009] The present invention has been conceived in recognition of the above problems, and an object of the present invention is to provide an electrode lead having a structure capable of minimizing electrical resistance and an electrode lead manufacturing method for manufacturing such an electrode lead.

[0010] An electrode lead according to the present invention is an electrode lead connected to an electrode assembly of a secondary battery, and includes 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 have a narrower width than the second portion, and a plating layer may be formed on at least a portion of the first portion and the second portion.

[0011] Each of the first and second parts may have a three-layer structure in which an aluminum layer, a copper layer, and an aluminum layer are laminated in that order.

[0012] The plating layer can be formed on a surface of the first part where the copper layer is exposed and a surface of the second part where the first part is connected.

[0013] The thicknesses of the plurality of aluminum layers are the same, and the thicknesses of the aluminum layer and the copper layer can be 1:1 to 1:8.

[0014] The above plating layer may be composed of a nickel material.

[0015] A lead film made of an insulating material may be attached to the first portion.

[0016] The above lead film can cover a boundary area that touches the second portion of the first portion.

[0017] A 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 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.

[0018] The above notching step may be characterized by including a step of forming a plurality of notching grooves on one side of a metal plate surface having a three-layer structure in which an aluminum layer, a copper layer, and an aluminum layer are sequentially laminated.

[0019] The above notching step may include a step of forming a plurality of notching grooves at equal intervals on one side of the metal plate surface.

[0020] The above plating step may be characterized by including a step of forming a plating layer on one side of the metal plate surface and on a surface of the plurality of notching grooves where the copper layer is exposed.

[0021] The above plating step may include a step of forming a plating layer made of a nickel material on one side of the metal plate surface and on a plurality of the notching grooves.

[0022] Meanwhile, the electrode lead manufacturing method is performed after the cutting step, and may further include a film attachment step of attaching a lead film of insulating material to the cut metal plate surface.

[0023] The cut metal plate surface may include 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 attaching step may be a step of attaching the lead film to a boundary area of ​​the first portion that is in contact with the second portion.

[0024] 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 a case of a secondary battery, wherein the first portion is formed to have a narrower 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 large, thereby having the effect of lowering the electrical resistance of the electrode lead.

[0025] FIG. 1 is a drawing for comparing the width and length of the first part and the second part in an electrode lead according to the present invention.

[0026] Figure 2 is a drawing showing a plating layer formed on a first portion of an electrode lead according to the present invention.

[0027] FIG. 3 is a drawing showing a lead film attached to a first portion of an electrode lead according to the present invention.

[0028] Figure 4 is a flowchart sequentially showing the steps of a method for manufacturing an electrode lead according to the present invention.

[0029] Figure 5 is a drawing for explaining a notching step in a method for manufacturing an electrode lead according to the present invention.

[0030] Figure 6 is a drawing for explaining a plating step in a method for manufacturing an electrode lead according to the present invention.

[0031] Figure 7 is a drawing for explaining a film attachment step in a method for manufacturing an electrode lead according to the present invention.

[0032] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

[0033] In order to clearly explain the present invention, a detailed description of a part that is irrelevant to the description or a related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and when adding reference signs to components of each drawing in this specification, the same or similar reference signs are attached to the same or similar components throughout the specification.

[0034] In addition, terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0035] Hereinafter, an electrode lead and an electrode lead manufacturing method according to the present invention will be described with reference to the drawings.

[0036] electrode leads

[0037] Fig. 1 is a drawing for comparing the width and length 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 on a first portion in an electrode lead according to the present invention.

[0038] 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 portion (100) coupled to an electrode tab of the electrode assembly and a second portion (200) connected to the first portion (100) and protruding outside the case of the secondary battery. At this time, the first portion (100) is formed to have a narrower width than the second portion (200), and a plating layer (300) may be formed on the first portion (100). Specifically, the plating layer (300) may be formed on at least a portion of the first portion (100) and the second portion (200). That is, the plating layer (300) may be formed on at least a portion of the first portion (100) and / or at least a portion of the second portion (200).

[0039] 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, since the electrode lead (10) has the second portion (200) having a relatively large cross-sectional area, the average cross-sectional area of ​​the electrode lead (10) may also increase. Therefore, the electrode lead (10) according to the present invention may have a relatively low overall resistance value, and may be suitable for rapid charging and high-output battery design.

[0040] Specifically, the first part (100) is a part welded to the electrode tab of the electrode assembly, and thus the first part (100) may have the same width as the electrode tab. On the other hand, the width size of the second part (200) that is not welded to the electrode tab may not be limited to the width size of the electrode tab. The electrode lead (10) according to the present invention is characterized in that the width size of the second part (200) is increased, thereby widening the cross-sectional area of ​​the second part (200). In this case, compared to designing the width size of the entire electrode lead to be the same as the width size of the electrode tab, the resistance value of the electrode lead (10) can be designed to be low by increasing the average cross-sectional area of ​​the electrode lead (10).

[0041] In addition, in the electrode lead (10) according to the present invention, the plating layer (300) is formed mainly on the first part (100) that is coupled to the electrode tab of the electrode assembly, thereby effectively preventing the first part (100) inserted into the internal space of the case of the secondary battery from being damaged. 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 region of the first part (100) composed of copper and the electrolyte, thereby preventing or delaying oxidation of the first part (100) by the electrolyte.

[0042] Accordingly, since the first part (100) has high durability as the plating layer (300) is formed, the first part (100) may not be easily damaged even in an internal environment where the potential fluctuates due to charging and discharging of the secondary battery.

[0043] The electrode assembly is a laminate comprising a plurality of electrodes and separators, and may have various structures. For example, the electrode assembly may be a stacked electrode assembly in which a plurality of electrodes and separators are alternately laminated. In addition, the electrode assembly may be a stack-folded electrode assembly in which a plurality of electrodes and separators are laminated in one direction and then folded, or a jelly roll-type electrode assembly in which electrodes and separators are alternately laminated and then rolled.

[0044] An electrode tab is formed or connected to each electrode included in an electrode assembly, and may include an electrode uncoated portion excluding an electrode coated portion coated with an active material among the electrodes. In addition, the electrode tab may be a conductive tab or sheet separately connected to the electrode.

[0045] The secondary battery case is an outer covering material that encloses the aforementioned electrode assembly and electrode tabs, and may be configured in various ways. For example, a rigid outer covering material made of metal or non-metal may be used for the secondary battery case.

[0046] Additionally, the case of the secondary battery may be a pouch-shaped outer material composed of a laminate sheet. This 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 and / or inner surfaces of the metal layer.

[0047] The metal layer can serve as a substrate that maintains mechanical strength and a barrier layer that prevents the infiltration of moisture and oxygen. In addition to preventing the inflow or leakage of foreign substances such as gas and moisture, the metal layer can be composed of aluminum or an aluminum alloy to enhance the strength of the battery case. Examples of aluminum alloys that can be used include alloy numbers 8079, 1N30, 8021, 3003, 3004, 3005, 3104, and 3105, and these can be used alone or in combination.

[0048] The first resin layer coated on the outer surface of the metal layer must have excellent resistance to the external environment in order to protect the electrode assembly from the outside. Therefore, the first resin layer is required to have excellent tensile strength and corrosion resistance relative to its thickness. For the first resin layer, a polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), a polyolefin resin such as polyethylene or polypropylene, etc. can be used.

[0049] The second resin layer coated on the inner surface of the metal layer can be bonded to each other 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, CPP (Casted Polypropylene), chlorinated polypropylene, polyethylene, ethylene propylene copolymer, polyethylene and acrylic acid copolymer, and polypropylene and acrylic acid copolymer can be used for the second resin layer.

[0050] 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 to the outside of the case of the secondary battery. This 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.

[0051] The electrode lead (10) according to the present invention may be configured with a structure having a low resistance value. Specifically, the electrode lead (10) may be configured with a first portion (100) coupled to an electrode tab and a second portion (200) connected to the first portion (100) and protruding outside the case of the secondary battery.

[0052] Here, the length of the width (L1) of the first portion (100) may be formed shorter than the length of the width (L2) of the second portion (200). In this case, the width (L1) of the portion inserted into the case of the secondary battery may be formed narrow, and the width (L2) of the portion inserted into the outside of the case of the secondary battery may be formed relatively wide.

[0053] Considering the electrolyte, etc. injected into the internal space of the case of the secondary battery, the narrower the width (L1) of the portion of the electrode lead (10) inserted into the case of the secondary battery, the better. However, if the width of the entire electrode lead (10) is formed narrow, the electrode lead (10) will have a narrow cross-sectional area, which may lead to a problem of having a high resistance value.

[0054] In the case of the electrode lead (10) according to the present invention, the width (L1) of the portion inserted into the case of the secondary battery is formed narrow, thereby improving the space utilization of the internal space of the case of the secondary battery, and at the same time, the width (L2) of the portion protruding outside the case of the secondary battery is formed wide, thereby having the advantageous effect of forming a low resistance value of the electrode lead (10).

[0055] 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 laminated.

[0056] 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 laminated. In addition, in the case of the second part (200), it may also have a three-layer structure in which an aluminum layer (210), a copper layer (220), and an aluminum layer (230) are laminated. In this way, since the first part (100) and the second part (200) constituting the electrode lead (10) each include a copper layer (120, 220) having a low electrical resistance, the electrical resistance value of the electrode lead (10) can be reduced compared to a case in which the entire electrode lead (10) is composed only of an aluminum layer having a relatively high electrical resistance.

[0057] 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. Similarly, 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.

[0058] Specifically, in the case of the first portion (100), the plurality of aluminum layers (110, 130) forming it may have substantially the same thickness. In addition, 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 increasing the thickness of the copper layer (120) having a relatively low resistance, there is an advantageous effect of lowering the resistance value of the first portion (100).

[0059] In addition, in the case of the second part (200), the plurality of aluminum layers (210, 230) forming it may have substantially the same thickness. In addition, 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 increasing the thickness of the copper layer (220) having a relatively low resistance, there is an advantageous effect of lowering the resistance value of the second part (200).

[0060] Meanwhile, a plating layer (300) may be formed on the first portion (100) of the electrode lead (10) that is inserted into the case of the secondary battery. The plating layer (300) is formed of a metal with low reactivity, and thus can protect the first portion (100) from the electrolyte injected into the internal space of the secondary battery case.

[0061] In particular, since the first part (100) has a copper layer (120) made 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 highly reactive copper layer (120) from contacting the electrolyte within the case of the secondary battery, thereby preventing the copper layer (120) from being oxidized.

[0062] In addition, 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 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 laminated, and one surface of the first part (100) may be connected to the second part (200). At this time, the copper layer (120) is exposed on three sidewall surfaces of the first part (100), and the metal layer (300) may be formed only on three sidewall surfaces 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 a metal material used in forming the plating layer (300) and completely blocking the exposure of the copper layer (120).

[0063] The plating layer (300) is composed of a metal with low reactivity, and various materials can be used. For example, the plating layer (300) can be composed of a nickel (Ni) material with low reactivity. In this case, oxidation of the copper layer (120) by the electrolyte can be effectively prevented.

[0064] Meanwhile, the plating layer (300) may also be formed on the surface where the first portion (100) of the second portion (200) protrudes. Specifically, the plating layer (300) may be formed only on the surface where the copper layer (220) of the second portion (200) is exposed, and may be formed only on the surface where the first portion (100) protrudes. In this case, the copper layer (220) of the second portion (200) may be prevented from contacting the electrolyte within the case of the secondary battery, thereby preventing oxidation of the copper layer (220).

[0065] In addition, although not shown in FIG. 2, the plating layer (300) may be formed only on the first portion (100) among the first portion (100) and the second portion (200). In this case, the plating layer (300) is formed only on the surface of the first portion (100) where the copper layer (120) is exposed, and the plating layer (300) may not be formed on the surface of the first portion (100) where the copper layer (120) is not exposed.

[0066] FIG. 3 is a drawing showing a lead film attached to a first portion of an electrode lead according to the present invention.

[0067] Referring to Fig. 3, a lead film (400) made of an insulating material may be attached to a first part (100) constituting an electrode lead (10). The lead film (400) is adhered to the electrode lead (10) so that when the electrode lead (10) is later inserted into a battery case, an insulation state can be maintained between the electrode lead (10) and the battery case.

[0068] This lead film (400) can be attached to the electrode lead (10) in various ways. For example, the lead film (400) is an insulating tape having an adhesive layer formed on one side, and can be attached to the electrode lead (10) with the adhesive layer facing the electrode lead (10).

[0069] In addition, as illustrated in FIG. 3, the lead film (400) can cover a boundary area that is in contact with the second portion (200) of the first portion (100). At this time, since the second portion (200) is relatively wide and is positioned outside the boundary area, the lead film (400) can be prevented from moving outward by the second portion (200). In this case, there is an advantageous effect of being able to prevent 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).

[0070] Electrode lead manufacturing method

[0071] Figure 4 is a flowchart sequentially showing the steps of the electrode lead manufacturing method according to the present invention. Figure 5 is a drawing for explaining the notching step in the electrode lead manufacturing method according to the present invention. Figure 6 is a drawing for explaining the plating step in the electrode lead manufacturing method according to the present invention.

[0072] Referring to FIGS. 4 to 6, a 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 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).

[0073] According to this electrode lead manufacturing method, an electrode lead (10) can be manufactured in which the width of the portion inserted into the case of the secondary battery and coupled to the electrode tab of the electrode assembly is formed narrow, and the width of the portion protruding outside the case of the secondary battery is formed relatively wide. In this case, there is an advantageous effect of being able to reconsider the space utilization of the internal space of the secondary battery case by forming the width of the portion inserted into the case of the secondary battery narrow. In addition, there is an advantageous effect of being able to form a low resistance value of the electrode lead (10) by forming the width of the portion protruding outside the case of the secondary battery wide.

[0074] 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 the second portion having a relatively large cross-sectional area, the average cross-sectional area of ​​the electrode lead (10) may also increase. Therefore, the electrode lead (10) manufactured by the electrode lead manufacturing method according to the present invention has a relatively low overall resistance value, and may be suitable for rapid charging and high-output battery design.

[0075] Specifically, the first part is a part welded to the electrode tab of the electrode assembly, and thus the first part may have the same width as the electrode tab. On the other hand, the width size of the second part that is not welded to the electrode tab may not be limited to the width size of the electrode tab. The electrode lead (10) manufactured by the electrode lead manufacturing method according to the present invention is characterized in that the width size of the second part is increased, thereby widening the cross-sectional area size of the second part (200). In this case, compared to designing the width size of the entire electrode lead to be the same as the width size of the electrode tab, the average cross-sectional area size of the electrode lead (10) can be increased, thereby designing the overall resistance value to be low.

[0076] 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 in which an aluminum layer (510), a copper layer (520), and an aluminum layer (530) are sequentially laminated. Here, the notching grooves (540) may be formed in various ways.

[0077] For example, the notching grooves (540) may be formed by an optical device such as a laser device. Additionally, the notching grooves (540) may be formed by a press device that physically presses one side (501) of the metal plate surface (500).

[0078] In the notching step (S10), a plurality of notching grooves (540) formed on one side (501) of the metal plate surface (500) can be formed in various orders. For example, the plurality of notching grooves (540) can be formed sequentially in one direction, or the plurality of notching grooves (540) can be formed simultaneously.

[0079] 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.

[0080] 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 a surface where the copper layer (520) is exposed among the plurality of notching grooves (540). This plating layer (550) may be composed of a metal with low reactivity.

[0081] When the metal plate surface (500) is processed into an electrode lead (10), the portion where the plating layer (550) is formed may correspond to a 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 of 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 case of the secondary battery.

[0082] 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 exposure of the copper layer (520). After the metal plate surface (500) is processed into an electrode lead (10), the plating layer (550) can block the highly reactive copper layer (520) from contacting the electrolyte inside the secondary battery case, thereby preventing the copper layer (520) from being oxidized. That is, the plating layer (550) can be formed on a portion of the metal plate surface (500) that will be inserted into the case of the secondary battery after being processed into the electrode lead (10), thereby preventing the copper layer (520) of the corresponding portion from being oxidized by the electrolyte.

[0083] Meanwhile, the aforementioned plating step (S20) may be a step of forming a plating layer (550) made of a nickel material on one side (501) of the metal plate surface (500) and a plurality of notched grooves (540). In this case, the plating layer (550) is made 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.

[0084] In the plating step (S20), a plating layer (550) made of Ni material can be formed mainly on a portion of the metal plate surface (500) that will be processed into an electrode lead (10) and then inserted into the case of the secondary battery. That is, the plating layer (550) can be formed only on a portion of the metal plate surface (500) where the copper layer (520) is exposed.

[0085] 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 plurality of 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 simultaneously cut by a cutting device such as a laser cutter.

[0086] Figure 7 is a drawing for explaining a film attachment step in a method for manufacturing an electrode lead according to the present invention.

[0087] 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) of attaching a lead film (560) of insulating material 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.

[0088] The lead film (400) is adhered to the electrode lead (10) so that when the electrode lead (10) is later inserted into the battery case, an insulation state can be maintained between the electrode lead (10) and the battery case.

[0089] Meanwhile, in the film attachment step (S40), the lead film (560) can be attached to various locations of the cut metal plate surface (500). For example, the cut metal plate surface (500) can include a first portion having a relatively narrow width (D1) and a second portion connected to the first portion and having a relatively wider width (D2) than the first portion. In the film attachment step (S40), the lead film (560) can be attached to a boundary area of ​​the first portion that is in contact with the second portion.

[0090] At this time, a second portion having a relatively wide width (D2) is positioned outside 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 being able to prevent 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).

[0091] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various embodiments are possible within the scope equivalent to the technical idea of ​​the present invention and the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0092] [Explanation of symbols]

[0093] 10: Electrode lead 100: Part 1

[0094] 110, 130: Aluminum layer 120: Copper layer

[0095] 200: Second part 210, 230: Aluminum layer

[0096] 220: Copper layer 300: Plating layer

[0097] 400: Lead film 500: Metal plate

[0098] 510, 530: Aluminum layer 520: Copper layer

[0099] 540: Notching groove 550: Plating layer

[0100] S10: Notching step S20: Plating step

[0101] S30: Cutting stage S40: Film attachment stage

Claims

1. As an electrode lead connected to the electrode assembly of a secondary battery, A first part coupled to the electrode tab of the electrode assembly; and A second part connected to the first part and protruding outside the case of the secondary battery, The first part is formed to have a narrower width than the second part, An electrode lead having a plating layer formed on at least a portion of the first portion and the second portion.

2. In claim 1, An electrode lead characterized in that each of the first and second parts has a three-layer structure in which an aluminum layer, a copper layer, and an aluminum layer are laminated in that order.

3. In claim 2, An electrode lead characterized in that the plating layer is formed on a surface of the first portion where the copper layer is exposed and on a surface of the second portion where the first portion is connected.

4. In claim 2, An electrode lead characterized in that the thicknesses of the plurality of aluminum layers are the same, and the thicknesses of the aluminum layer and the copper layer are 1:1 to 1:

8.

5. In claim 1, An electrode lead characterized in that the above plating layer is composed of nickel material.

6. In claim 1, An electrode lead characterized in that a lead film made of an insulating material is attached to the first part.

7. In claim 6, An electrode lead characterized in that the lead film covers a boundary area that is in contact with the second portion of the first portion.

8. A method for manufacturing an electrode lead connected to an electrode assembly of a secondary battery, 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 a plurality of the notching grooves; and A method for manufacturing an electrode lead, comprising 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.

9. In claim 8, The above notching step is, A method for manufacturing an electrode lead, characterized by comprising a step of forming a plurality of notching grooves on one side of a metal plate having a three-layer structure in which an aluminum layer, a copper layer, and an aluminum layer are sequentially laminated.

10. In claim 8, The above notching step is, A method for manufacturing an electrode lead, characterized by including a step of forming a plurality of notching grooves at equal intervals on one side of the metal plate surface.

11. In claim 9, The above plating step is, A method for manufacturing an electrode lead, characterized in that it comprises a step of forming a plating layer on one side of the metal plate surface and on a surface where the copper layer is exposed among the plurality of notching grooves.

12. In claim 8, The above plating step is, A method for manufacturing an electrode lead, characterized by comprising a step of forming a plating layer made of nickel material on one side of the metal plate surface and on a plurality of the notching grooves.

13. In claim 8, A method for manufacturing an electrode lead, characterized in that it further includes a film attachment step of attaching a lead film of an insulating material to a cut metal plate surface, which is performed after the above cutting step.

14. In claim 13, The above cut metal plate surface includes 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, A method for manufacturing an electrode lead, characterized in that the film attachment step is a step of attaching the lead film to a boundary area in contact with the second part of the first part.

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