Method for producing anticorrosion layer and cylindrical secondary battery

Abstract

The present specification relates to a method for producing a corrosion protection layer, A method for manufacturing a corrosion prevention layer for a cylindrical secondary battery, the method comprising: a jelly-roll type electrode assembly having a structure in which a first electrode, a second electrode, and a separator interposed therebetween are wound in one direction around a winding shaft; a battery can containing the electrode assembly and including a metal plating layer; and a connection lead plate connecting the battery can and the electrode assembly, (A) applying a resin for a corrosion prevention layer to a portion of the metal plating layer that is damaged at a weld formed by melting the connection lead plate and the battery can when welding the outer bottom surface of the battery can; and (B) curing the resin for the corrosion prevention layer with ultraviolet light to form a corrosion prevention layer. Including, The resin for the corrosion prevention layer includes one or more liquid substances, The one or more liquid substances are UV-curable and have a viscosity of 1 cP or more and 5000 cP or less. A method for producing a corrosion protection layer is provided.

Description

[Technical field]

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2021-0030319 filed with the Korean Intellectual Property Office on March 8, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a method for producing a corrosion prevention layer and a cylindrical secondary battery, and more particularly to a method for producing a corrosion prevention layer capable of preventing corrosion of a battery can and a cylindrical secondary battery. [Background technology]

[0003] Conventional cylindrical secondary batteries have a structure in which a tab connecting a jelly roll electrode assembly to an external terminal is welded to the foil of the jelly roll electrode assembly, and have problems in that the current path is limited and the resistance of the jelly roll electrode assembly itself is high.

[0004] To improve this, attempts have been made to reduce the resistance by increasing the number of taps, but there is a limit to ensuring sufficient current paths and reducing the resistance to a desired level. To overcome this limit, attempts have been made to reduce the resistance in the welding process applied to the battery can.

[0005] However, the exterior of the battery can of a cylindrical secondary battery is usually made of a metal plating layer, and the electrode welding process is laser welding, and since welding of the bottom may proceed from the exterior of the battery can made of a metal plating layer, there is a possibility that the metal plating layer constituting the exterior of the battery can may be damaged.

[0006] If the metal plating layer is damaged in this manner, the surface becomes exposed to air, which may cause corrosion of the battery can.

[0007] To solve this problem, a method of applying an anti-rust solution to the metal plating layer and then washing it has been applied, but even with this method, the components of the anti-rust solution can be easily removed, which makes the battery can easily corrode.

[0008] Therefore, there is a need for other materials or methods for comprehensively solving the above problems and effectively preventing corrosion of battery cans. Summary of the Invention [Problem to be solved by the invention]

[0009] In order to solve the above problems, one object of the present invention is to provide a method for manufacturing a corrosion prevention layer and a cylindrical secondary battery.

[0010] However, the problems that the present invention aims to solve are not limited to the above problems, and other problems not mentioned in this specification can be clearly understood by those of ordinary skill in the art from the description of the invention described below. [Means for solving the problem]

[0011] In order to achieve the above object, the present invention provides a method for producing a corrosion prevention layer and a secondary battery according to the following aspects.

[0012] According to one aspect of the present invention, there is provided a method for manufacturing a corrosion prevention layer for a cylindrical secondary battery, the method comprising: a jelly-roll type electrode assembly having a structure in which a first electrode, a second electrode, and a separator interposed therebetween are wound in one direction around a winding shaft; a battery can containing the electrode assembly and including a metal plating layer; and a connection lead plate connecting the battery can and the electrode assembly, (A) applying a resin for a corrosion prevention layer to a portion of the metal plating layer that is damaged at a welded portion formed by melting the connection lead plate and the battery can when the bottom surface of the outside of the battery can is welded; and (B) curing the resin for the corrosion prevention layer with ultraviolet light to form a corrosion prevention layer. Including, The resin for the corrosion prevention layer includes one or more liquid substances, The one or more liquid substances are ultraviolet curable and have a viscosity of 1 cP or more and 5000 cP or less. A method for producing a corrosion protection layer is provided.

[0013] According to one aspect of the present invention, there is provided a jelly-roll type electrode assembly having a structure in which a first electrode, a second electrode, and a separator interposed therebetween are wound in one direction around a winding shaft; a battery can housing the electrode assembly and including a metal plating layer; a connection lead plate that joins the battery can and the electrode assembly; and A corrosion prevention layer manufactured by the above-mentioned method for manufacturing a corrosion prevention layer. The present invention provides a cylindrical secondary battery comprising:

[0014] According to one aspect of the present invention, there is provided a jelly-roll type electrode assembly having a structure in which a first electrode, a second electrode, and a separator interposed therebetween are wound in one direction around a winding shaft; a battery can housing the electrode assembly and including a metal plating layer; a connection lead plate that joins the battery can and the electrode assembly; and A corrosion prevention layer is disposed at a portion where the outer surface of the battery can is damaged at a welded portion formed by melting the connection lead plate on the bottom surface of the outer side of the battery can and the battery can. The present invention provides a cylindrical secondary battery comprising: Effect of the Invention

[0015] The method for manufacturing a corrosion prevention layer and the cylindrical secondary battery according to one aspect of the present invention can prevent corrosion of the battery can due to damaged areas of the metal plating layer caused by welding on the battery can, thereby preventing product defects.

[0016] The method for manufacturing the corrosion prevention layer according to one aspect of the present invention is simple since the resin for the corrosion prevention layer is easily cured by ultraviolet light. In addition, after the resin for the corrosion prevention layer is applied, the metal plating layer present on the outside of the battery can is prevented from being exposed to corrosion factors such as air and moisture, thereby preventing corrosion of the battery can and improving the safety of the battery.

[0017] The method for manufacturing a corrosion prevention layer and the cylindrical secondary battery according to one aspect of the present invention can provide the advantage of not being deformed during the activation process (usually, leaving the battery under high temperature and high humidity conditions (temperature of about 65°C or higher, humidity of about 90% or higher) for about 24 hours). However, the effects obtained by the present invention are not limited to the effects described above, and other technical effects not mentioned in this specification can be clearly understood by those of ordinary skill in the art from the description of the invention described below. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic diagram showing an embodiment of the present invention; [Diagram 2] 1 is a schematic diagram showing an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The present invention can be modified in various ways and can include several examples or embodiments, but specific examples or concrete examples are shown in the drawings and will be described in detail based on them. However, this is not intended to limit the present invention to a specific embodiment, and it should be understood that the present invention includes all modifications, equivalents, or alternatives included in the technical spirit and technical scope of the present invention.

[0020] In this specification, terms such as first, second, A, B, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only to distinguish one component from another. For example, a first component may be named a second component, and similarly, a second component may be named a first component, without departing from the scope of the present invention.

[0021] As used herein, terms such as "and / or" include combinations of multiple associated items or portions of multiple associated items.

[0022] In this specification, when a certain component is expressed in the singular, it may include a plural concept unless otherwise specified in the specification.

[0023] In this specification, unless otherwise specified in the specification, the terms "comprise", "have", and the like refer to the existence of features, numbers, steps, operations, processes, components, members, etc., or combinations thereof described in this specification, and do not refer to the exclusion of other features, numbers, etc.

[0024] As used herein, the term "battery can" refers to a battery can that has an opening, cylindrical sides and a bottom (or bottom surface) and is typically made of a metal or alloy material. Preferably, the battery can is made of nickel-plated iron (a battery can that includes iron and a nickel-containing metal plating layer).

[0025] The "battery can" is an object that houses an electrode assembly of a secondary battery. The battery can may be cylindrical, and its size may be a circular diameter of 30 mm to 55 mm at both ends and a height of 60 mm to 120 mm. For example, the circular diameter x height of the cylindrical battery can may be 40 mm x 60 mm, 40 mm x 80 mm, 40 mm x 90 mm, or 40 mm x 120 mm.

[0026] In this specification, the term "secondary battery" refers to a battery that can be used repeatedly for a long period of time through recharging. Secondary batteries can be classified into nickel-cadmium secondary batteries, lithium-ion secondary batteries, etc., depending on the electrode active material.

[0027] In this specification, the term "cylindrical secondary battery" refers to a secondary battery having a cylindrical shape or a similar shape. Cylindrical secondary batteries are often used in large-capacity electronic and electrical devices due to their high energy density per volume, and can be used in a form in which a plurality of cylindrical secondary batteries are combined to form a battery pack. For example, a cylindrical secondary battery can have a structure in which a rivet inserted through the bottom on the opposite side of the opening is used as a cathode, and the battery can itself is used as an anode.

[0028] As used herein, the term "first electrode" is the cathode and the term "second electrode" is the anode, or vice versa.

[0029] As used herein, the term "cathode" includes a cathode current collector and a cathode active material applied to at least one surface of the cathode current collector. Examples of cathode current collectors include, but are not limited to, aluminum or alloys. Examples of cathode active materials include, but are not limited to, lithium-containing transition metal oxides.

[0030] As used herein, the term "anode" includes an anode current collector and an anode active material applied to at least one surface of the anode current collector. Examples of the anode current collector may be, but are not limited to, copper or an alloy. Examples of the anode active material include, but are not limited to, carbon materials.

[0031] In the present specification, the term "separation membrane" refers to a membrane interposed between the cathode and the anode, and serves to facilitate the movement of ions required to break the circuit while separating the cathode and the anode. Examples of the separation membrane include, but are not limited to, microporous films made of polyolefin-based membranes.

[0032] As used herein, the term "liquid substance" refers to a substance that maintains a liquid state at room temperature (about 25°C).

[0033] In this specification, the term "ultraviolet ray curable" refers to the property of being cured by ultraviolet ray. For example, when a certain substance is "ultraviolet ray curable", it means that the certain substance hardens and hardens by ultraviolet ray.

[0034] As used herein, the term "metal plating layer" refers to a layer applied to the outer surface of a battery can, which includes a metal plating material, and may be, for example, a nickel plating layer.

[0035] As used herein, the term "damaged portion" refers to an area where the exterior of the battery can (including the metal plating layer, if applied with a metal plating layer) is damaged by the welding process. The welding process is usually performed on the exterior of the bottom of the battery can. However, such a welding process may damage the metal plating layer. This may result in the electrolyte leaking due to easy exposure to a corrosive environment such as air or moisture.

[0036] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0037] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0038] According to one embodiment of the present invention, there is provided a method for manufacturing a corrosion prevention layer of a cylindrical secondary battery, the method comprising: a jelly-roll type electrode assembly having a structure in which a first electrode, a second electrode, and a separator interposed therebetween are wound in one direction around a winding shaft; a battery can containing the electrode assembly and including a metal plating layer; and a connection lead plate connecting the battery can and the electrode assembly, (A) applying a resin for a corrosion prevention layer to a portion of the metal plating layer that is damaged at a welded portion formed by melting the connection lead plate and the battery can when the bottom surface of the outside of the battery can is welded; and (B) curing the resin for the corrosion prevention layer with ultraviolet light to form a corrosion prevention layer. Including, The resin for the corrosion prevention layer includes one or more liquid substances, The one or more liquid substances are ultraviolet curable and have a viscosity of 1 cP or more and 5000 cP or less. A method for producing a corrosion protection layer is provided.

[0039] For example, the resin for the corrosion prevention layer may have a viscosity of 1 cP or more, 200 cP or more, 400 cP or more, 600 cP or more, 800 cP or more, 1000 cP or more, 1200 cP or more, 1400 cP or more, 1600 cP or more, 1800 cP or more, 2000 cP or more, 2200 cP or more, or 2400 cP or more.

[0040] In addition, the resin for the corrosion prevention layer may have a viscosity of 5000 cP or less, 4800 cP or less, 4600 cP or less, 4400 cP or less, 4200 cP or less, 4000 cP or less, 3800 cP or less, 3600 cP or less, 3400 CP or less, 3200 CP or less, 3000 CP or less, 2800 CP or less, or 2600 CP or less.

[0041] In relation to this embodiment, referring to FIG. 1 and / or FIG. 2, it is shown that the resin 4 for the corrosion prevention layer is cured by ultraviolet light 7 to form the corrosion prevention layer 6.

[0042] 2B shows the process of spraying the resin 4 for the corrosion prevention layer onto the battery can 1, and then irradiating the resin 4 with ultraviolet light 7 to harden the resin 4 for the corrosion prevention layer, i.e., to form the corrosion prevention layer 6. The spraying method is a conventional method.

[0043] The resin for the corrosion prevention layer used in the embodiment prevents corrosion by blocking corrosion factors such as contact of air and moisture with the damaged portion of the battery can. The resin for the corrosion prevention layer is characterized by UV curing and low viscosity. The corrosion prevention layer formed from such a resin can be formed with a uniform thickness, can prevent air bubbles from being generated in the corrosion prevention layer, and can provide excellent physical properties in terms of heat resistance, heat conductivity, etc. In addition, the corrosion prevention layer formed from the resin for the corrosion prevention layer does not deform during the activation process (usually, left for about 24 hours under high temperature and high humidity conditions (temperature of about 65°C or higher, humidity of about 90% or higher)).

[0044] The resin for the corrosion prevention layer may be applied by a method suitable in the art. The spraying may be performed through equipment such as a nozzle 5, and the discharge amount and discharge pressure applied to the nozzle may be selected within a range suitable in the art. The irradiation with the ultraviolet light 7 may be performed through equipment such as a UV lamp 8, and the wavelength of light applied to the light source of the UV lamp may be selected within a range suitable in the art.

[0045] The method for manufacturing a corrosion prevention layer according to the embodiment uses one or more UV-curable liquid substances in the resin for the corrosion prevention layer, which simplifies the process. In addition, the corrosion prevention layer formed from the resin for the corrosion prevention layer uses one or more liquid substances having a low viscosity of 1 cP to 5000 cP, so that the corrosion prevention layer formed from the resin for the corrosion prevention layer is formed with a uniform thickness, can prevent air bubbles from being generated in the corrosion prevention layer, and can provide excellent physical properties in terms of heat resistance, heat transfer, etc. In addition, the corrosion prevention layer formed by the above manufacturing method prevents corrosion factors such as contact of air and moisture with the metal plating layer, thereby preventing corrosion of the battery can. In addition, the corrosion prevention layer formed from the resin for the corrosion prevention layer according to the embodiment does not deform during the subsequent activation process (usually, left for about 24 hours under high temperature and high humidity conditions (temperature of about 65° C. or higher, humidity of about 90% or higher)).

[0046] In particular, the problem of peeling and corrosion of the coating layer formed by the conventional inkjet printing method can be eliminated.

[0047] According to another embodiment of the present invention, the resin for the corrosion prevention layer further includes a luminescent material, (C) The method for producing a corrosion prevention layer further includes a step of checking the coating state of the resin for the corrosion prevention layer on the battery can with ultraviolet light.

[0048] In the manufacturing method according to the embodiment, the resin for the corrosion prevention layer is applied to the portion where the outer surface of the battery can is damaged by the luminescent material, so that the corrosion prevention can be more effectively achieved.

[0049] If necessary, a cleavable valve may be provided in the battery can to discharge the internal gas to the outside when pressure increases due to gas present inside the cylindrical secondary battery. In this case, the method may further include forming a corrosion prevention layer by avoiding the cleavable valve.

[0050] In another embodiment, the resin for the corrosion prevention layer includes at least one selected from the group consisting of epoxy-based, acrylate-based, silicone-based, and urethane acrylic-based resins.

[0051] With regard to the embodiment, referring to FIG. 2(B), a resin 4 for the corrosion prevention layer, which includes at least one selected from the above-mentioned epoxy-based, acrylate-based, silicone-based, and urethane acrylic-based resins, is sprayed and applied onto a battery can 1, and referring to FIG. 2(C), a process is shown in which the resin 4 for the corrosion prevention layer is irradiated with ultraviolet light 7 to harden the resin 4 for the corrosion prevention layer, i.e., form a corrosion prevention layer 6.

[0052] In the method for manufacturing the corrosion prevention layer according to the embodiment, the resin for the corrosion prevention layer includes at least one selected from among epoxy-based, acrylate-based, silicone-based, and urethane acrylic-based resins having UV curing and low viscosity properties. This simplifies the process for forming the corrosion prevention layer, makes it possible to form the corrosion prevention layer with a uniform thickness, prevents air bubbles from being generated in the corrosion prevention layer, and provides excellent physical properties in terms of heat resistance, heat conductivity, etc.

[0053] According to another embodiment of the present invention, there is provided a method for producing a corrosion prevention layer, wherein the curing time in step (B) is 5 seconds to 30 seconds.

[0054] Preferably, the curing time may be 5 seconds or more, 10 seconds or more, or 15 seconds or more.

[0055] Preferably, the cure time may be 30 seconds or less, 25 seconds or less, or 20 seconds or less.

[0056] 2B, the resin 4 for the corrosion prevention layer is sprayed and applied onto the battery can 1. Also, FIG 2C shows a process of irradiating ultraviolet light 7 for 5 to 30 seconds to cure the resin 4 for the corrosion prevention layer, thereby forming a corrosion prevention layer 6.

[0057] The method for manufacturing the corrosion prevention layer according to the embodiment provides a rapid process due to a short curing time of 5 to 30 seconds, and the secondary battery satisfying the above range can ensure safety.

[0058] According to another embodiment, the battery can includes iron, and a method for manufacturing a corrosion prevention layer is provided.

[0059] According to another embodiment, the metal plating layer includes nickel.

[0060] The manufacturing method according to the embodiment can primarily prevent corrosion of the battery can by providing a metal plating layer (or a layer containing nickel). However, when the bottom surface of the battery can is welded from the outside, the metal plating layer may also melt, exposing the surface of the battery can. However, in the embodiment, after welding the battery can including the metal plating layer, a corrosion prevention layer is provided on the portion damaged by welding, thereby preventing the surface of the battery can from being exposed.

[0061] According to another embodiment of the present invention, there is provided a method for manufacturing a corrosion prevention layer, wherein the thickness of the corrosion prevention layer is more than 1 μm and less than 10 μm.

[0062] Preferably, the thickness of the corrosion protection layer may be greater than 1 μm, greater than 2 μm, greater than 3 μm, greater than 4 μm, or greater than 5 μm.

[0063] Preferably, the thickness of the corrosion protection layer may be less than 10 μm, less than 9 μm, less than 8 μm, less than 7 μm, or less than 6 μm.

[0064] When the thickness range according to the embodiment is satisfied, optimization for the cell size range of the secondary battery is possible.

[0065] According to another embodiment of the present invention, there is provided a corrosion prevention layer manufactured according to any of the manufacturing methods of the above embodiments.

[0066] In this embodiment, referring to FIG. 1 or FIG. 2, the corrosion prevention layer 6 is formed by curing a resin for the corrosion prevention layer provided at a welded portion 3 located on a metal plating layer 2 applied to a battery can 1 with ultraviolet light 7.

[0067] The corrosion prevention layer according to the embodiment prevents corrosion of the battery can by blocking corrosion factors such as contact of air and moisture with the metal plating layer. Since the resin for the corrosion prevention layer uses one or more liquid substances that are UV-curable and have low viscosity, the corrosion prevention layer formed using the same has a uniform thickness, is almost bubble-free, and has excellent physical properties in terms of heat resistance, heat transfer, etc. In addition, the corrosion prevention layer does not deform during the activation process (usually left for about 24 hours under high temperature and high humidity conditions (temperature of about 65°C or higher, humidity of about 90% or higher)).

[0068] In addition, the corrosion prevention layer can also solve the problem of corrosion occurring due to peeling of a coating layer formed by a conventional inkjet printing method.

[0069] According to one embodiment of the present invention, there is provided a jelly-roll type electrode assembly having a structure in which a first electrode, a second electrode, and a separator interposed therebetween are wound in one direction around a winding shaft; a battery can housing the electrode assembly and including a metal plating layer; a connection lead plate that joins the battery can and the electrode assembly; and A corrosion prevention layer manufactured by any of the above-mentioned methods for manufacturing a corrosion prevention layer. The present invention provides a cylindrical secondary battery comprising:

[0070] Alternatively, according to one embodiment of the present invention, a jelly-roll type electrode assembly having a structure in which a first electrode, a second electrode, and a separator interposed therebetween are wound in one direction around a winding shaft; a battery can housing the electrode assembly and including a metal plating layer; a connection lead plate that joins the battery can and the electrode assembly; and a corrosion prevention layer disposed at a portion where the outer surface of the battery can is damaged at a welded portion formed by melting the connection lead plate and the battery can on the outer bottom surface of the battery can; The present invention provides a cylindrical secondary battery comprising:

[0071] With reference to FIG. 1C or FIG. 2C of this embodiment, there is shown an electrode assembly (not shown) having a structure in which a first electrode, a separator, and a second electrode are sequentially stacked and wound, and a corrosion prevention layer 6 located on a welded portion 3 located on a metal plating layer 2 applied to the outer bottom surface 1 of a battery can.

[0072] The secondary battery according to the embodiment includes a corrosion prevention layer that prevents corrosion of the battery can by blocking corrosion factors such as contact of air or moisture with the metal plating layer, and includes a corrosion prevention layer that is uniform in thickness, has almost no air bubbles, and has excellent physical properties in terms of heat resistance, heat transfer, etc. Also, the corrosion prevention layer does not deform during an activation process (usually, leaving the battery under high temperature and high humidity conditions (temperature of about 65°C or higher, humidity of about 90% or higher) for about 24 hours). Therefore, the cylindrical secondary battery including the corrosion prevention layer has stability and / or safety. Furthermore, when the corrosion prevention layer is included, the defective rate of the cylindrical secondary battery can be minimized.

[0073] If necessary, a cleavable valve may be provided on the battery can to discharge the internal gas to the outside when pressure increases due to gas present inside the cylindrical secondary battery. In this case, the cleavable valve may be avoided and a corrosion prevention layer may be formed.

[0074] According to another embodiment, the corrosion prevention layer includes a resin for a corrosion prevention layer, The resin for the corrosion prevention layer is at least one selected from the group consisting of epoxy-based, acrylate-based, silicone-based and urethane-acrylic-based resins.

[0075] With respect to this embodiment, referring to FIG. 2(B), it is shown that a resin 4 for the corrosion prevention layer, which includes at least one selected from the above-mentioned epoxy-based, acrylate-based, silicone-based, and urethane acrylic-based resins, is sprayed and applied onto a battery can (1).

[0076] The cylindrical secondary battery according to the embodiment includes at least one selected from epoxy-based, acrylate-based, silicone-based, and urethane acrylic-based resins having UV-curable and low viscosity properties as a resin for the corrosion prevention layer, so that the process for forming the corrosion prevention layer is simple, the corrosion prevention layer can be formed to a uniform thickness, air bubbles can be prevented from being generated in the corrosion prevention layer, and excellent physical properties can be provided in terms of heat resistance, heat conductivity, etc.

[0077] According to another embodiment, the resin for the corrosion prevention layer further includes a light emitting material, providing a cylindrical secondary battery.

[0078] In the cylindrical secondary battery according to the embodiment, the resin for the corrosion prevention layer is coated with a luminescent material at the damaged portion of the outer surface of the battery can, thereby more efficiently preventing corrosion.

[0079] According to another embodiment, the battery can provides a cylindrical secondary battery containing iron.

[0080] According to another embodiment, the metal plating layer may include nickel to provide a cylindrical secondary battery.

[0081] The cylindrical secondary battery according to the embodiment can primarily prevent corrosion of the battery can containing iron by providing a metal plating layer (or containing nickel). However, when the bottom surface of the battery can is welded from the outside, the metal plating layer may also melt, exposing the surface of the battery can. However, in the embodiment, after welding the battery can containing the metal plating layer, a corrosion prevention layer is provided on the portion damaged by welding, thereby preventing the surface of the battery can from being exposed.

[0082] According to another embodiment, there is provided a cylindrical secondary battery, wherein the corrosion prevention layer has a thickness of more than 1 μm and less than 10 μm.

[0083] Preferably, the thickness of the corrosion protection layer may be greater than 1 μm, greater than 2 μm, greater than 3 μm, greater than 4 μm, or greater than 5 μm.

[0084] Preferably, the thickness of the corrosion protection layer may be less than 10 μm, less than 9 μm, less than 8 μm, less than 7 μm, or less than 6 μm.

[0085] When the thickness range according to the embodiment is satisfied, optimization for the cell size range of the secondary battery is possible.

[0086] Although the above describes a preferred embodiment of the present invention, the present invention is not limited thereto, and various modifications can be made within the scope of the claims and the detailed description of the invention, which also fall within the scope of the present invention. [Explanation of symbols]

[0087] 1 Battery can 2. Metal plating layer 3. Welded parts 4. Resin for corrosion prevention layer 5 Nozzle 6. Corrosion prevention layer 7. Ultraviolet Rays 8. UV lamp

Claims

1. A method for manufacturing a corrosion prevention layer for a cylindrical secondary battery, comprising: a jelly-roll type electrode assembly having a structure in which a first electrode, a second electrode, and a separator interposed therebetween are wound in one direction around a winding shaft; a battery can containing the electrode assembly and including a metal plating layer; and a connection lead plate connecting the battery can and the electrode assembly, (A) applying a resin for a corrosion prevention layer to a portion of the metal plating layer that is damaged at a welded portion formed by melting the connection lead plate and the battery can when welding the bottom surface of the outside of the battery can; and (B) curing the resin for the corrosion prevention layer with ultraviolet light to form a corrosion prevention layer; Including, The resin for the corrosion prevention layer includes one or more liquid substances, The one or more liquid substances are ultraviolet curable and have a viscosity of 1 cP or more and 5000 cP or less. Method for producing the corrosion protection layer.

2. The resin for the corrosion prevention layer further comprises a luminescent material, The method for manufacturing a corrosion prevention layer according to claim 1 , further comprising: (C) checking a coating state of the resin for the corrosion prevention layer on the battery can with ultraviolet light.

3. 3. The method for producing a corrosion prevention layer according to claim 1, wherein the resin for the corrosion prevention layer is at least one selected from the group consisting of epoxy-based, acrylate-based, silicone-based and urethane acrylic-based resins.

4. The method for producing a corrosion prevention layer according to claim 1 , wherein the curing time in step (B) is from 5 seconds to 30 seconds.

5. The method for producing a corrosion prevention layer according to claim 1 , wherein the battery can contains iron.

6. The method for producing a corrosion prevention layer according to claim 1 , wherein the metal plating layer comprises nickel.

7. The method for producing a corrosion prevention layer according to claim 1 , wherein the thickness of the corrosion prevention layer is more than 1 μm and less than 10 μm.

8. A jelly-roll type electrode assembly having a structure in which a first electrode, a second electrode, and a separator interposed therebetween are wound in one direction around a winding shaft; a battery can housing the electrode assembly and including a metal plating layer; a connection lead plate that joins the battery can and the electrode assembly; and A corrosion prevention layer disposed on a welded portion formed by melting the connection lead plate and the battery can on the bottom surface of the outside of the battery can. Including, The corrosion prevention layer includes a resin for a corrosion prevention layer, The corrosion prevention layer is formed by curing the resin for the corrosion prevention layer with ultraviolet light.

9. A jelly-roll type electrode assembly having a structure in which a first electrode, a second electrode, and a separator interposed therebetween are wound in one direction around a winding shaft; a battery can housing the electrode assembly and including a metal plating layer; a connection lead plate that joins the battery can and the electrode assembly; and a corrosion prevention layer disposed at a portion where the outer surface of the battery can is damaged at a welded portion formed by melting the connection lead plate on the bottom surface of the outer side of the battery can and the battery can; Including, The corrosion prevention layer includes a resin for a corrosion prevention layer, The corrosion prevention layer is formed by curing the resin for the corrosion prevention layer with ultraviolet light.

10. A cylindrical secondary battery as described in claim 8 or 9, wherein the resin for the corrosion prevention layer is at least one selected from epoxy-based, acrylate-based, silicone-based and urethane acrylic-based resins.

11. A jelly-roll type electrode assembly having a structure in which a first electrode, a second electrode, and a separation membrane interposed therebetween are wound in one direction around a winding shaft; a battery can housing the electrode assembly and including a metal plating layer; a connection lead plate that joins the battery can and the electrode assembly; and A corrosion prevention layer disposed on a welded portion formed by melting the connection lead plate and the battery can on the bottom surface of the outside of the battery can. Including, The corrosion prevention layer includes a resin for a corrosion prevention layer, the resin for the corrosion prevention layer is at least one selected from the group consisting of epoxy-based, acrylate-based, silicone-based and urethane-acrylic-based resins; The resin for the corrosion prevention layer further contains a luminescent material.

12. A jelly-roll type electrode assembly having a structure in which a first electrode, a second electrode, and a separation membrane interposed therebetween are wound in one direction around a winding shaft; a battery can housing the electrode assembly and including a metal plating layer; a connection lead plate that joins the battery can and the electrode assembly; and a corrosion prevention layer disposed at a portion where the outer surface of the battery can is damaged at a welded portion formed by melting the connection lead plate on the bottom surface of the outer side of the battery can and the battery can; Including, The corrosion prevention layer includes a resin for a corrosion prevention layer, the resin for the corrosion prevention layer is at least one selected from the group consisting of epoxy-based, acrylate-based, silicone-based and urethane-acrylic-based resins; The resin for the corrosion prevention layer further contains a luminescent material.

13. The cylindrical secondary battery according to claim 8 , wherein the battery can contains iron.

14. The cylindrical secondary battery according to claim 8 , wherein the metal plating layer contains nickel.

15. The cylindrical secondary battery according to claim 8 , wherein the corrosion prevention layer has a thickness of more than 1 μm and less than 10 μm.

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