Secondary battery and method for manufacturing secondary battery

Abstract

According to one aspect of the present disclosure, there may be provided a secondary battery including: an electrode assembly formed by winding a positive electrode, a negative electrode, and a separator, and including a protruding region in which an uncoated portion protrudes and a non-protruding region in which the uncoated portion does not protrude at an upper portion of the electrode assembly; a current collector coupled to the protruding region so as to be electrically connected to the electrode assembly; and a case accommodating the electrode assembly, the electrode assembly including a groove portion formed by bending at least a portion of the protruding region, the current collector including a protruding portion inserted into the groove portion, the non-protruding region includes an inner non-protruding region located on an inner side of the protruding region in a central direction, which is a direction toward a winding axis around which the electrode assembly is wound, and an outer non-protruding region located on an outer side of the protruding region.

Description

Technical Field

[0001] The present disclosure relates to a secondary battery and a method for manufacturing the secondary battery. Background Art

[0002] A secondary battery is one of energy storage devices that can be charged and discharged. Secondary batteries are widely used in various devices that use electricity as a power source. For example, secondary batteries are used as energy storage devices in various devices from small devices such as mobile phones, laptop computers, and tablet computers to large devices such as vehicles and aircraft. In particular, in recent years, the application of secondary batteries as power sources for vehicles has been actively explored.

[0003] Secondary batteries can be classified into lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, etc. according to the materials of the electrodes, etc. Various types of secondary batteries can be appropriately selected according to the design capacity, use environment, etc. In addition, the secondary battery can be an all-solid-state battery that uses a solid electrolyte instead of a liquid electrolyte. Compared with other types of secondary batteries, lithium-ion batteries can achieve relatively high voltages and capacities. Therefore, lithium-ion batteries are widely used in fields that require high-density energy storage devices such as vehicle battery packs.

[0004] Secondary batteries such as lithium-ion batteries can include a positive electrode plate, a negative electrode plate, a separator, an electrolyte, etc. The positive electrode plate and the negative electrode plate are disposed with a separator made of an insulating material therebetween, and charging or discharging can be achieved by the movement of ions in the electrolyte.

[0005] Secondary batteries can be manufactured into flexible pouch-type battery cells or rigid prismatic or cylindrical can-type battery cells. Summary of the Invention

[0006] (I) Technical Problems to be Solved

[0007] According to one aspect of the present disclosure, the process of the secondary battery can be improved.

[0008] According to one aspect of the present disclosure, the defects of the secondary battery caused by foreign matters can be reduced.

[0009] The secondary battery and the method for manufacturing the secondary battery of the present disclosure can be widely applied to green technology fields such as electric vehicles and battery charging stations. In addition, the secondary battery and the method for manufacturing the secondary battery of the present disclosure can be used for eco-friendly electric vehicles (Electric Vehicle), hybrid vehicles, etc. that prevent climate change by suppressing air pollution and greenhouse gas emissions.

[0010] (2) Technical Solution

[0011] The secondary battery according to the present disclosure may include: an electrode assembly formed by winding a positive electrode, a negative electrode, and a separator, and including a protruding region where an uncoated portion protrudes and a non-protruding region where the uncoated portion does not protrude above the electrode assembly; a current collector coupled to the protruding region to be electrically connected to the electrode assembly; and a housing accommodating the electrode assembly. The electrode assembly includes a groove portion formed by bending at least a part of the protruding region. The current collector includes a protruding portion inserted into the groove portion. The non-protruding region includes an inner non-protruding region located inside the protruding region in the central direction and an outer non-protruding region located outside the protruding region. The central direction is the direction toward the winding axis around which the electrode assembly is wound.

[0012] According to one embodiment, the groove portion may be formed by pressing at least a part of the protruding region in the central direction.

[0013] According to one embodiment, the width of the groove portion may gradually decrease in the central direction.

[0014] According to one embodiment, the width of the groove portion may be constant.

[0015] According to one embodiment, the electrode assembly may form a first hole at the center, and the positive electrode, the negative electrode, and the separator are not provided in the first hole.

[0016] According to one embodiment, at least a part of the groove portion may be bent to be located above the inner non-protruding region and not on the first hole.

[0017] According to one embodiment, the current collector may include a plurality of second holes formed at intervals from the central portion.

[0018] According to one embodiment, the current collector may further include a current collecting post protruding from the central portion.

[0019] According to one embodiment, a plurality of the groove portions and the protruding portions may be formed.

[0020] According to one embodiment, the width of the inner non-protruding region, that is, the difference between the outer diameter and the inner diameter of the inner non-protruding region, may be equal to or greater than the height of the uncoated portion of the protruding region.

[0021] The manufacturing method of a secondary battery according to the present disclosure may include the following steps: a preparation step of preparing an electrode assembly formed by winding a positive electrode, a negative electrode, and a separator, and including a protruding region where an uncoated portion protrudes and a non-protruding region where the uncoated portion does not protrude on the upper portion of the electrode assembly; a pressing step of forming a groove portion by bending at least a part of the protruding region; an assembling step of inserting a protruding portion of a current collector into the groove portion to assemble the current collector and the electrode assembly; and a welding step of welding a region of the protruding portion.

[0022] According to an embodiment, the pressing step may be a step of pressing at least a part of the protruding region in a central direction, which is a direction toward a winding axis around which the electrode assembly is wound.

[0023] According to an embodiment, the welding step may be a step of irradiating a laser on an upper portion of the current collector assembled in the assembling step to perform welding.

[0024] (III) Beneficial effects

[0025] According to one aspect of the present disclosure, the process of the secondary battery can be improved.

[0026] According to one aspect of the present disclosure, defects of the secondary battery due to foreign matters can be reduced. Description of the drawings

[0027] Figure 1 is an exploded perspective view showing a secondary battery.

[0028] Figure 2 is a plan view showing an upper portion of an electrode assembly.

[0029] Figure 3 is a plan view showing an upper portion of an electrode assembly according to a modified embodiment.

[0030] Figure 4 is along Figure 2 sectional view taken along line I-I'.

[0031] Figure 5 is along Figure 2 sectional view taken along line II-II'.

[0032] Figure 6 is along Figure 2 sectional view taken along line I-I'.

[0033] Figure 7 is a bottom view showing a lower portion of a current collector.

[0034] Figure 8 is a side view showing a side of a current collector.

[0035] Figure 9 is a side view showing a side surface of a current collector according to a modified embodiment.

[0036] Figure 10 is a flowchart showing a method of manufacturing a secondary battery.

[0037] Description of reference numerals:

[0038] 10: Secondary battery

[0039] 100: Case

[0040] 110: Main body portion

[0041] 120: Cover

[0042] 200: Electrode assembly

[0043] 210: Protruding area

[0044] 211: Groove portion

[0045] 220: Non-protruding area

[0046] 221: Inner non-protruding area

[0047] 222: Outer non-protruding area

[0048] 230: First hole

[0049] 240: Coated portion

[0050] 250: Uncoated portion

[0051] 300: Current collector

[0052] 310: Protruding portion

[0053] 320: Second hole

[0054] 340: Current collecting post

[0055] P: Pressing device

[0056] d: Width of the inner non-protruding area

[0057] h: Height of the uncoated portion

[0058] A: Winding shaft

[0059] W: Welding strip Detailed description of the embodiments

[0060] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. For convenience, in the following description, detailed descriptions of structures that would obscure the gist of the present disclosure or known structures will be omitted.

[0061] The following embodiments are provided to more fully illustrate the present disclosure to those skilled in the art to which the present disclosure pertains. The following embodiments are provided to assist in understanding the present disclosure, and the technical concept of the present disclosure is not limited to the specific embodiments described below. The present disclosure should be understood to broadly include various equivalents, alternatives, modifications, etc. that implement the technical concept described in the following embodiments.

[0062] The terms used in the following embodiments are provided to more fully illustrate specific embodiments in accordance with the above viewpoints. Therefore, the terms used in the following embodiments should not be construed as narrowing, limiting, or restricting the use of the technical concept of the present disclosure.

[0063] In the following description, unless explicitly excluded in the context, a singular expression may be construed to include a plural. Additionally, in the following description, the expression "comprising" means the presence of the described structures, components, operations, features, steps, numbers, etc., and does not mean the exclusion of the addition of one or more other structures, components, operations, features, steps, numbers, etc.

[0064] The secondary battery described in this specification may include a battery capable of charging and discharging. For example, the secondary battery may include a lead-acid battery, a nickel-cadmium battery, a nickel-metal hydride battery, a lithium-ion battery, etc. In this specification, it is mainly assumed that the secondary battery is a lithium-ion battery. However, it should be understood that the technical concepts described in this specification may also be applicable to other suitable types of batteries other than lithium-ion batteries.

[0065] In the detailed description of the present disclosure, the terms or words used in the following specification and claims should not be construed as limited to the general meaning or dictionary meaning, but should be interpreted based on the principle that the inventor can appropriately define the concept of the term in order to best illustrate his own invention, so as to conform to the meaning and concept of the technical thought of the present disclosure. Therefore, it should be understood that the embodiments described in this specification and the structures shown in the drawings are only the most preferred embodiments of the present disclosure, and do not represent all the technical thoughts of the present disclosure. At the time of filing this application, there may be various equivalents and variants that can replace them.

[0066] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the drawings. At this time, the same components are denoted by the same reference numerals as much as possible in the drawings. In addition, detailed descriptions of well-known functions and structures that may obscure the gist of the present disclosure are omitted. For the same reason, some components in the drawings are exaggerated, omitted, or shown schematically, and the dimensions of each component do not exactly reflect the actual dimensions. For example, in this specification, expressions such as upper side, upper part, above, lower side, lower part, below, side surface, etc. are described based on the illustration. If the direction of the corresponding object changes, it may be described in a different way.

[0067] Hereinafter, a secondary battery and a method for manufacturing the secondary battery according to the present disclosure will be described in detail with reference to the accompanying drawings.

[0068] Figure 1 is an exploded perspective view showing the secondary battery 10, Figure 2 is a plan view showing the upper part of the electrode assembly 200, Figure 3 is a plan view showing the upper part of the electrode assembly 200 according to a modified embodiment, Figure 4 is along Figure 2 a cross-sectional view taken along the line I-I' of Figure 5 is along Figure 2 a cross-sectional view taken along the line II-II' of Figure 6 is along Figure 2 a cross-sectional view taken along the line I-I' of

[0069] Figure 2 shows a partial process of forming the groove portion 211 in the upper part of the electrode assembly 200 during the manufacturing process of the secondary battery 10, Figure 3 shows another form of the groove portion 211. Figure 4 shows the process of inserting the electrode assembly 200 into the housing 100. Figure 6 shows a state where the welding bar W is inserted from the lower part of the first hole 230 of the electrode assembly 200 during the manufacturing process of the secondary battery 10.

[0070] Referring to Figures 1 to 6 , the secondary battery 10 according to the present disclosure may include an electrode assembly 200 and a housing 100.

[0071] The housing 100 may accommodate the electrode assembly 200.

[0072] The housing 100 may also be referred to as a can. The housing 100 may be formed to include a hollow space inside to accommodate the electrode assembly 200. The housing 100 may have a cylindrical or circular cylindrical shape. Therefore, the housing 100 having a cylindrical or circular cylindrical shape may include a hollow space having a cylindrical or circular cylindrical shape inside, and the electrode assembly 200 may be accommodated in the hollow space. The housing 100 may contain a conductive material. For example, it may be nickel-plated steel, stainless steel, aluminum, etc.

[0073] The housing 100 may include a main body portion 110 and a cover 120.

[0074] The main body portion 110 may be a structure with at least one of the upper and lower portions open. That is, at least one of the upper surface and the lower surface of the main body portion 110 is open. The main body portion 110 may be in a form where both the upper and lower portions are open, or may be in a form where the lower portion is open, or may be in a form where the upper portion is open. The electrode assembly 200 may be inserted into the interior of the housing 100 through the open upper surface or the open lower surface. The main body portion 110 may have various shapes. For example, the main body portion 110 may include a cylindrical or circular cylindrical shape. Refer to Figure 1 , the main body portion 110 in the present disclosure is illustrated as a circular cylinder with an open lower portion.

[0075] The cover 120 may seal the open lower portion of the main body portion 110. For example, the cover 120 may be coupled to the lower portion of the main body portion 110 to seal the open lower portion of the main body portion 110. The method of sealing the lower portion of the main body portion 110 may adopt various methods. For example, the main body portion 110 and the cover 120 may be welded. The welding may adopt various welding methods. For example, a laser welding method may be adopted. The edge of the cover 120 may be welded in a state where it is coupled to the main body portion 110.

[0076] The electrode assembly 200 may include a positive electrode, a negative electrode, and a separator. The electrode assembly 200 may be formed by winding the positive electrode, the negative electrode, and the separator. The separator may be composed of an insulator interposed between the negative electrode and the positive electrode. The electrode assembly 200 may be configured as a stacked type in which the positive electrode, the negative electrode, and the separator are alternately stacked. Or, the electrode assembly 200 may be configured as a jelly roll type in which the positive electrode, the negative electrode, and the separator interposed between the positive electrode and the negative electrode are alternately stacked (stack) and wound in a roll type. In the present disclosure, the electrode assembly 200 is shown as a jelly roll type, but is not necessarily limited thereto.

[0077] The positive electrode and the negative electrode may have a structure in which a positive electrode active material or a negative electrode active material is coated on a foil, respectively. For example, the negative electrode may be formed by coating graphite or the like on a foil of copper or nickel material, and the positive electrode may be formed by coating a transition metal oxide active material on a foil of aluminum material.

[0078] At least a part of the positive electrode and the negative electrode may not be coated with the active material. The portions of the positive electrode and the negative electrode regions that are not coated with the active material may be respectively referred to as uncoated portions 250.

[0079] At the upper part of the electrode assembly 200, there may be a protruding area 210 where the uncoated part 250 protrudes and a non-protruding area 220 where the uncoated part 250 does not protrude. There may be an uncoated part 250 at the upper part of the foil before the foil is wound. At this time, the uncoated part 250 may correspond to either the positive electrode or the negative electrode. At the lower part of the electrode assembly 200, there may be an uncoated part 250 corresponding to the opposite electrode. The electrode assembly 200 may be formed by winding the electrode plate after removing a predetermined area of the uncoated part 250. At this time, after winding, the area remaining in a protruding state at the upper part of the electrode assembly 200 may be the protruding area 210, and the area where the uncoated part 250 is removed may be the non-protruding area 220. The upper part of the electrode assembly 200 may be divided into a protruding area 210 and a non-protruding area 220, and the protruding area 210 may protrude more upward than the non-protruding area 220. The lower parts of the protruding area 210 and the non-protruding area 220 may have a coated part 240. The coated part 240 may be a part including the foil coated with the active material.

[0080] The electrode assembly 200 may include a groove part 211 formed by bending at least a part of the protruding area 210. The groove part 211 may be a part bent by pressing a part of the protruding uncoated part 250. Therefore, the groove part 211 may have a shape that is more recessed downward than other parts of the protruding area 210.

[0081] The groove part 211 may be formed by pressing at least a part of the protruding area 210 in the central direction. The central direction mentioned here may be the direction toward the winding axis A around which the electrode assembly 200 is wound. In other words, the central direction may be the direction toward the first hole 230 formed at the center of the electrode assembly 200. Refer to Figure 2 There may be a pressing device P for pressing the protruding area 210 in order to form the groove part 211. The pressing device P may move from the outside of the electrode assembly 200 toward the central direction and press the protruding area 210. The pressing device P may tilt and bend the uncoated part 250 in the central direction. Refer to Figure 4 The groove part 211 may be tilted in the central direction.

[0082] The width of the groove part 211 may gradually decrease in the central direction. Refer to Figure 2 The width of the groove part 211 may gradually decrease from the outside to the inside of the electrode assembly 200. The width of the groove part 211 may refer to the width of the groove part 211 when viewed from above. In order to form the groove part 211 with a narrowing width, the pressing device P may correspondingly include a shape with a thinner width toward the front.

[0083] The width of the groove part 211 may also be constant. Refer to Figure 3 The width of the groove part 211 may be constant from the outside to the inside of the electrode assembly 200.

[0084] A plurality of groove portions 211 may be formed, and a plurality of protruding portions 310 may also be formed. For example, a plurality of groove portions 211 may be formed at a predetermined interval with respect to the winding shaft A, and a plurality of protruding portions 310 inserted into the groove portions 211 may also be formed at corresponding positions.

[0085] Figure 2 and Figure 3 The shape and width of the groove portion 211 shown are merely examples. Therefore, it is not limited thereto and may be appropriately modified as needed. For example, contrary to the groove portion 211 in Figure 2 the groove portion 211 may also have a shape in which the width gradually increases toward the inside. The groove portion 211 provides a space for the protruding portion 310 of the current collector 300 to be described later, and may increase the welding area with the current collector 300. Therefore, the shape of the groove portion 211 may be appropriately changed within the scope of achieving the object of the present disclosure.

[0086] Since the groove portion 211 is formed by bending the uncoated portion 250 without cutting the uncoated portion 250, foreign matters may not be generated during the formation of the groove portion 211. If the groove portion 211 is formed by cutting the uncoated portion 250, a small amount of metal fragments may be generated in the cut portion, and these metal fragments may move inside the secondary battery 10, resulting in an electrical short circuit or a reduction in battery efficiency. Therefore, the secondary battery 10 of the present disclosure may not generate such foreign matters.

[0087] The non-protruding area 220 may include an inner non-protruding area 221 and an outer non-protruding area 222. Specifically, the non-protruding area 220 may include an inner non-protruding area 221 located inside the protruding area 210 in the central direction and an outer non-protruding area 222 located outside the protruding area 210. Referring to Figure 2 , with the protruding area 210 as a reference, non-protruding areas 220 may be formed outside and inside the protruding area 210, respectively. The non-protruding area 220 located outside the protruding area 210 may be the outer non-protruding area 222. On the contrary, the non-protruding area 220 located inside the protruding area 210 may be the inner non-protruding area 221. Therefore, the outer non-protruding area 222, the protruding area 210, and the inner non-protruding area 221 may be sequentially arranged from the outside to the inside.

[0088] Due to the formation of the outer non-protruding area 222, it is possible to prevent the uncoated portion 250 from being deformed due to collision with the case 100 during the insertion of the electrode assembly 200 into the case 100. Referring to Figure 4When the electrode assembly 200 is inserted upward through the open lower part of the housing 100, collisions may occur between the main body part 110 of the housing 100 and the uncoated part 250 at the upper part. Collisions of the uncoated part 250 may cause defects during the manufacturing process, and deformation of the uncoated part 250 may cause poor contact with the current collector 300. Therefore, due to the formation of the outer non-protruding area 222, the possibility of collision between the uncoated part 250 and the housing 100 can be reduced.

[0089] In addition, due to the formation of the outer non-protruding area 222, electrical connection between the uncoated part 250 and the housing 100 after the electrode assembly 200 is inserted into the housing 100 can be prevented. For example, if the uncoated part 250 at the upper part is the positive electrode, the housing 100 may be connected to the negative electrode of the electrode assembly 200. Therefore, if the positive electrode uncoated part 250 contacts the negative electrode housing 100, an electrical short circuit may occur. The outer non-protruding area 222 can separate the uncoated part 250 from the outside, thereby reducing the possibility of contact between the housing 100 and the uncoated part 250.

[0090] The electrode assembly 200 may form a first hole 230 at the center, and no positive electrode, negative electrode, and separator are provided in the first hole 230. In other words, a hole can be formed axially along the winding axis A of the electrode assembly 200. The first hole 230 can be formed to extend axially along the electrode assembly 200.

[0091] During the manufacturing process of the secondary battery 10, a welding bar W can be inserted to weld the upper electrode terminal. In addition, the electrolyte can also be injected through the first hole 230. Refer to Figure 6 As shown, the welding bar W can be inserted from the lower part through the first hole 230. The inserted welding bar W can weld the upper electrode terminal and then exit from the lower part again. Therefore, if the first hole 230 is blocked by other structures, the movement path of the welding bar W will be hindered during the manufacturing process of the secondary battery 10, which may cause manufacturing defects.

[0092] During the process of forming the groove part 211, the uncoated part 250 can bend toward the direction of the first hole 230. At this time, due to the formation of the inner non-protruding area 221, the groove part 211 does not lie on the path of the first hole 230. That is, at least a part of the groove part 211 may bend and be located above the inner non-protruding area 221, but not on the first hole 230.

[0093] For this reason, refer to Figure 5, the width d of the inner non-protruding region 221, which is the difference between the outer diameter and the inner diameter of the inner non-protruding region 221, may be equal to or greater than the height h of the uncoated portion 250 of the protruding region 210. If the height h of the uncoated portion 250 is greater than the width d of the inner non-protruding region 221, a part of the groove portion 211 may bend and cover at least a part of the first hole 230. Therefore, in order to prevent this situation, the height h of the uncoated portion 250 or the width d of the inner non-protruding region 221 may be appropriately restricted from each other. Alternatively, during the formation of the groove portion 211, the bending angle of the uncoated portion 250 may also be reduced.

[0094] Figure 7 is a bottom view showing the lower part of the current collector 300, Figure 8 is a side view showing the side of the current collector 300, Figure 9 is a side view showing the side of the current collector 300 according to a modified embodiment.

[0095] Referring to Figures 7 to 9 and Figures 1 to 6 , the secondary battery 10 may include a current collector 300.

[0096] The current collector 300 may be combined with the protruding region 210 to be electrically connected to the electrode assembly 200. The current collector 300 may be combined with the protruding region 210 located at the upper part of the electrode assembly 200 and may be accommodated in the housing 100. The electrode assembly 200 may be formed of a conductive material and may be combined with the protruding region 210 to be electrically connected to the positive electrode or the negative electrode of the electrode assembly 200. For example, the current collector 300 may be welded to the protruding region 210 to be electrically connected to the positive electrode of the electrode assembly 200.

[0097] The current collector 300 may be a disk-shaped plate. The current collector 300 may include a plurality of second holes 320 formed at a predetermined interval from the central portion. Through the plurality of second holes 320, the electrolyte may be smoothly injected into the upper part of the electrode assembly 200.

[0098] The current collector 300 may include a protruding portion 310 inserted into the groove portion 211. The protruding portion 310 may be formed to protrude downward at the lower part of the plate of the current collector 300. The protruding portion 310 may be formed at a position corresponding to the groove portion 211 so as to be inserted into the groove portion 211.

[0099] The current collector 300 can be stably coupled to the protruding region 210 by inserting the protruding portion 310 into the groove portion 211. For example, when the protruding portion 310 is inserted into the groove portion 211, the alignment of the current collector 300 with the protruding region 210 does not get misaligned. Additionally, the welding area corresponding to the region where the protruding portion 310 is inserted can be increased. The upper part of the current collector 300 where the protruding portion 310 is located can be welded while the protruding portion 310 is inserted into the groove portion 211.

[0100] As Figure 9 shown, the current collector 300 can further include a protruding current collecting post 340. For example, the current collecting post 340 can be a cylindrical post protruding upward from the central portion of the current collector 300, and a hollow space can be formed inside. The current collecting post 340 can be a structure provided to enhance the coupling force with an external terminal (omitted in the present disclosure).

[0101] Figure 10 is a flowchart showing a method of manufacturing a secondary battery.

[0102] Referring to Figure 10 and Figures 1 to 9 , the method of manufacturing the secondary battery 10 can include a preparation step S100, a pressing step S200, an assembly step S300, and a welding step S400.

[0103] The preparation step S100 can be a step of preparing the electrode assembly 200, which is formed by winding a positive electrode, a negative electrode, and a separator, and includes a protruding region 210 where the uncoated portion 250 protrudes and a non-protruding region 220 where the uncoated portion 250 does not protrude, above the electrode assembly 200. The structure of the electrode assembly 200 prepared in the preparation step S100 can be the same as or similar to the structure of the above-described electrode assembly 200.

[0104] The pressing step S200 can be a step of forming the groove portion 211 by bending at least a part of the protruding region 210. For example, at least a part of the protruding region 210 can be pressed using a pressing device P. At this time, the uncoated portion 250 can be pressed and bent. Specifically, at least a part of the protruding region 210 can be pressed in the central direction, which is the direction toward the winding axis A around which the electrode assembly 200 is wound, using the pressing device P. Referring to Figure 2 , the pressing device P can move from the outside to the inside in the central direction of the electrode assembly 200 to press the protruding region 210.

[0105] The assembling step S300 may be a step of inserting the protruding portion 310 of the current collector 300 into the groove portion 211 to assemble the current collector 300 and the electrode assembly 200. For example, the position of the current collector 300 may be adjusted so that the protruding portion 310 is inserted into the groove portion 211, and then the current collector 300 is placed on the upper part of the electrode assembly 200. At this time, the current collector 300 may be placed on the upper part of the protruding area 210.

[0106] The welding step S400 may be a step of welding the area of the protruding portion 310. For example, the current collector 300 placed on the upper part of the protruding area 210 may be welded to the protruding area 210. The area of the protruding portion 310 mentioned here may refer to the upper part of the current collector 300 corresponding to the part where the protruding portion 310 is located. Various welding methods may be used for welding, and one of the methods may be a laser welding method. For example, in the assembling step S300, laser light may be irradiated onto the upper part of the assembled current collector 300 to weld the current collector 300 and the protruding area 210. At this time, the position where the laser light is irradiated may be the area of the protruding portion 310.

[0107] In addition to the above steps, the manufacturing method of the secondary battery 10 may further include steps required for manufacturing the secondary battery 10, such as a step of inserting the electrode assembly 200 into the housing 100, a step of welding the cover 120 and the main body portion 110 to seal the housing 100, and a step of injecting an electrolyte into the sealed housing 100.

[0108] The embodiments of the present disclosure have been described in detail above, but the scope of the present disclosure is not limited thereto. It is obvious to those skilled in the art that various modifications and changes can be made without departing from the technical idea of the present disclosure recorded in the claims.

Claims

1. A secondary battery, comprising: An electrode assembly formed by winding a positive electrode, a negative electrode, and a separator, and including a protruding area where an uncoated portion protrudes and a non-protruding area where the uncoated portion does not protrude at an upper portion of the electrode assembly; A current collector coupled to the protruding area to be electrically connected to the electrode assembly; And A housing for accommodating the electrode assembly, The electrode assembly includes a groove portion formed by bending at least a part of the protruding area, The current collector includes a protruding portion inserted into the groove portion, The non-protruding area includes an inner non-protruding area located inside the protruding area in a central direction, which is a direction toward a winding axis around which the electrode assembly is wound, and an outer non-protruding area located outside the protruding area.

2. The secondary battery according to claim 1, wherein The groove portion is formed by pressing at least a part of the protruding area in the central direction.

3. The secondary battery according to claim 2, wherein The width of the groove portion gradually decreases in the central direction.

4. The secondary battery according to claim 2, wherein The width of the groove portion is constant.

5. The secondary battery according to claim 1, wherein The electrode assembly forms a first hole at a center, and the positive electrode, the negative electrode, and the separator are not provided in the first hole.

6. The secondary battery according to claim 5, wherein At least a part of the groove portion is bent to be located above the inner non-protruding area and not located on the first hole.

7. The secondary battery according to claim 5, wherein The current collector includes a plurality of second holes formed at intervals from a central portion.

8. The secondary battery according to claim 5, wherein The current collector further includes a current collecting post protruding from the central portion.

9. The secondary battery according to claim 1, wherein A plurality of the groove portions and the protruding portions are formed.

10. The secondary battery according to claim 1, wherein The width of the inner non-protruding area, that is, the difference between the outer diameter and the inner diameter of the inner non-protruding area, is equal to or greater than the height of the uncoated portion of the protruding area.

11. A method for manufacturing a secondary battery, comprising the following steps: A preparation step of preparing an electrode assembly formed by winding a positive electrode, a negative electrode, and a separator, and including a protruding area where an uncoated portion protrudes and a non-protruding area where the uncoated portion does not protrude at an upper portion of the electrode assembly; A pressing step of forming a groove portion by bending at least a part of the protruding area; An assembling step of inserting a protruding portion of a current collector into the groove portion to assemble the current collector and the electrode assembly; And A welding step of welding an area of the protruding portion.

12. The method for manufacturing a secondary battery according to claim 11, wherein The pressing step is a step of pressing at least a part of the protruding area in a central direction, which is a direction toward a winding axis around which the electrode assembly is wound.

13. The method for manufacturing a secondary battery according to claim 11, wherein The welding step is a step of irradiating a laser to the upper part of the current collector assembled in the assembling step to perform welding.

Images