Cylindrical rechargeable battery and method for manufacturing a cylindrical rechargeable battery

Abstract

The present invention relates to a cylindrical secondary battery and a method for manufacturing a cylindrical secondary battery, and moreover, when welding a current collector to an electrode assembly, the accuracy of the welding process and the positional accuracy of the welding are improved, there are no welding defects, a wider area can be made contact with lower energy than conventional methods, and by forming low resistance, not only the welding processability but also the resistive heat generated in the current collector can be reduced, thereby maximizing the high performance and high efficiency of the battery.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0087252 filed on July 5, 2023, and all the contents disclosed in the literature of the Korean Patent Application are incorporated herein by reference in their entirety.

[0002] The present invention relates to a cylindrical secondary battery and a method for manufacturing a cylindrical secondary battery. When welding a current collector to an electrode assembly, the accuracy of the welding process and the positional accuracy of welding are improved, there is no welding defect, a wide area can be contacted with low energy compared to the prior art, and by forming a low resistance, not only the welding processability but also the resistive heat generation occurring in the current collector can be reduced, maximizing the high performance and high efficiency of the battery. The present invention relates to a cylindrical secondary battery and a method for manufacturing a cylindrical secondary battery.

Background Art

[0003] Secondary batteries can be classified into cylindrical batteries and prismatic batteries in which an electrode assembly is incorporated into a cylindrical or prismatic metal can according to the shape of the battery case, and pouch-type batteries in which an electrode assembly is incorporated into a pouch-type case made of an aluminum laminate sheet.

[0004] In addition, the electrode assembly incorporated into the battery case is a power generation element capable of charge and discharge having a laminated structure of a positive electrode / separator / negative electrode, and a jelly roll-type structure wound with a separator interposed between long sheet-shaped positive and negative electrodes coated with an active material, a stack-type structure in which a large number of positive and negative electrodes of a predetermined size are sequentially laminated with a separator interposed therebetween, and a stack / folding-type electrode assembly having a structure in which a bicell or full cell obtained by laminating a positive electrode and a negative electrode of a predetermined unit with a separator interposed therebetween is wound.

[0005] Among these, the jelly roll type electrode assembly is widely manufactured due to its ease of production and high energy density per unit weight. The jelly roll type electrode assembly can be manufactured by assembling a laminate consisting of a long sheet-like positive electrode, a negative electrode, and a separator interposed between them, and then winding the sheet in the longitudinal direction with a winding core in contact with one end of the electrode laminate. Furthermore, such a jelly roll type electrode assembly can be inserted into a battery case made of a cylindrical metal can to form a cylindrical secondary battery.

[0006] Because these cylindrical rechargeable batteries are designed with high energy density, the demand for them is also tending to increase.

[0007] Among these cylindrical secondary batteries, the Tabless Cell, which is manufactured without tabs, has an energy density five times higher than conventional batteries and is a secondary battery with high investment efficiency. In the case of Tabless Cells manufactured in this way, instead of the conventional method of connecting electrode tabs to the can, the battery can be manufactured in a form in which a jelly roll type electrode assembly and a current collector are connected, and the current collector and the can are connected. For this purpose, the current collector plate and the jelly roll type electrode assembly can be joined by welding and then inserted into the can.

[0008] Figure 1 is a perspective view showing the current collector plate and the jelly roll-type electrode assembly separated. Figure 2 is a perspective view showing the current collector plate joined to the jelly roll-type electrode assembly by welding.

[0009] Referring to Figures 1 and 2, conventionally, when manufacturing cylindrical secondary batteries, a disc-shaped current collector is first placed on the upper end of a jelly roll-type electrode assembly (see Figure 1), and a welding laser is shone on the upper surface of the metal current collector to weld the current collector and the jelly roll-type electrode assembly together (see Figure 2).

[0010] However, conventionally, with tablet cells, there have been various problems in achieving high-quality welding when connecting the jelly roll electrode assembly and the current collector. The jelly roll electrode assembly is taller from the inside to the outside relative to the winding center axis O, which creates a gap between the current collector and the jelly roll electrode assembly. Such gaps cause defects when welded, affecting the yield of the battery manufacturing process. In particular, when welding is performed on the upper surface of the current collector while the welding laser moves radially along the current collector, welding is performed along a path with height differences on the upper surface of the jelly roll electrode assembly, and the degree of welding defects due to the aforementioned gap is more severe.

[0011] Furthermore, during welding on the upper surface of the metal current collector, variations in welding position occurred due to equipment tolerances and positional tolerances caused by vibration. Therefore, when welding the jelly roll type electrode assembly and the current collector, a design was needed that could minimize the influence of the gap and improve the welding process and welding positional accuracy. [Overview of the project] [Problems that the invention aims to solve]

[0012] The present invention was derived to solve the above-mentioned problems, and the object of the present invention is to provide a cylindrical secondary battery and a method for manufacturing a cylindrical secondary battery that, when welding a current collector to an electrode assembly, improves the accuracy of the welding process and the positional accuracy of the welding, eliminates welding defects, allows contact over a wide area with lower energy than conventional methods, and forms low resistance, thereby reducing not only the welding processability but also the resistive heat generated in the current collector, and maximizing the high performance and efficiency of the battery. [Means for solving the problem]

[0013] The present invention relates to a method for manufacturing a cylindrical secondary battery, which includes a jelly roll type electrode assembly formed by winding electrodes and a separator. The method includes a current collector placement step of placing a current collector having a through-hole formed at the end of the jelly roll type electrode assembly in the direction of the winding center axis, and a current collector welding step of joining the jelly roll type electrode assembly and the current collector by welding. In the current collector welding step, the corner (edge) of the through-hole of the jelly roll type electrode assembly and the current collector are welded in the circumferential direction.

[0014] In the current collector placement process, the current collector can be placed on the end of the jelly roll type electrode assembly such that the curved portion of the electrode end included in the jelly roll type electrode assembly and the curved portion of the corner (edge) of the current collector penetration opening correspond to each other.

[0015] The welding process for the current collector allows for welding the electrodes included in the jelly roll-type electrode assembly to the corners of the current collector's penetration port.

[0016] In the welding process for a current collector, the corner of the current collector penetration opening where welding is performed can be the outermost corner among the corners that form the periphery of the current collector penetration opening.

[0017] The welding process for the current collector can be performed by laser welding.

[0018] In the welding process for current collectors, when laser welding the corners of the jelly roll-type electrode assembly and the current collector penetration opening in the circumferential direction, the process can be carried out while drawing a predetermined welding pattern.

[0019] In the welding process for a current collector, the welding pattern may include at least one of either a zigzag or circular pattern.

[0020] The current collector has a slit-shaped through-hole, and the welding process for the current collector can involve laser welding the jelly roll-type electrode assembly to the corners of the slit-shaped through-hole.

[0021] In the welding process of the current collector, when laser welding is performed on the corner of the jelly roll type electrode assembly and the slit-shaped through hole in the circumferential direction, it can be performed while drawing a predetermined welding pattern.

[0022] In the welding process of the current collector, the welding pattern can include at least one of a zigzag or circular pattern.

[0023] The welding pattern is a zigzag pattern, and the width h of the zigzag pattern can be 1 / 2 or more of the thickness t of the current collector.

[0024] In the welding process of the current collector, the corner of the through hole formed in the circumferential direction of the current collector can be detected by using a laser scanner including a seam tracking function.

[0025] In the current collector, multi-purpose holes for injecting electrolyte or discharging gas can be formed.

[0026] The welding process of the current collector can be performed with at least one of the jelly roll type electrode assembly and the current collector fixed by using fixing fixtures.

[0027] The fixing fixtures include a pressing surface that presses the upper surface of the current collector and a guide surface that extends obliquely from the periphery of the pressing surface, and a welding hole where welding is performed can be formed at a position corresponding to the corner of the through hole of the current collector on the pressing surface.

[0028] The cylindrical secondary battery according to the present invention includes a jelly roll type electrode assembly formed by winding an electrode and a separator, and a current collector having a through hole formed therein and joined by welding to an end portion in the winding central axis direction of the jelly roll type electrode assembly, and the jelly roll type electrode assembly is welded to the edge of the through hole of the current collector in the circumferential direction.

[0029] The electrode included in the jelly roll type electrode assembly can be welded to the corner of the through hole of the current collector.

[0030] The corner of the welded current collector penetration can be the outermost corner among the corners that form the periphery of the current collector penetration.

[0031] The jelly roll electrode assembly and the corners (edges) of the current collector penetration can be joined by laser welding.

[0032] The circumferential laser welding of the jelly roll electrode assembly and the corner of the current collector penetration can be formed with a predetermined welding pattern.

[0033] The welding pattern may include at least one of the following: a zigzag pattern or a circular pattern.

[0034] The current collector has a slit-shaped through-hole, and the corners of the jelly roll-type electrode assembly and the slit-shaped through-hole can be joined by laser welding.

[0035] The circumferential laser welding of the jelly roll electrode assembly and the corners of the slit-shaped through-hole can be performed in a predetermined welding pattern.

[0036] The welding pattern may include at least one of the following: a zigzag pattern or a circular pattern.

[0037] The welding pattern is a zigzag pattern, and the width h of the zigzag pattern can be at least half the thickness t of the current collector.

[0038] The current collector may have a multi-purpose hole formed for injecting electrolyte or discharging gas. [Effects of the Invention]

[0039] The present invention relates to a cylindrical secondary battery and a method for manufacturing a cylindrical secondary battery. When welding a current collector to an electrode assembly, the accuracy of the welding process and the positional accuracy of the weld are improved, there are no welding defects, a wider area can be contacted with lower energy than in the conventional method, and low resistance is formed. This not only improves the ease of welding but also reduces the heat generated by resistance in the current collector, thereby maximizing the high performance and efficiency of the battery. [Brief explanation of the drawing]

[0040] [Figure 1] This is a perspective view illustrating the current collector plate and the jelly roll-type electrode assembly in a separated state. [Figure 2] This is a perspective view illustrating the state in which the current collector plate is joined to the jelly roll-type electrode assembly by welding. [Figure 3] This is a perspective view illustrating a method for manufacturing a cylindrical secondary battery according to one embodiment of the present invention. [Figure 4] Figure 3 is a front view taken from the front. [Figure 5] This is a perspective view illustrating a current collector and a jelly roll-type electrode assembly for a cylindrical secondary battery according to another embodiment of the present invention. [Figure 6] Figure 5 is a magnified perspective view showing the slit-shaped through-hole of the current collector. [Figure 7] This is a perspective view illustrating how a fixing device is used in a method for manufacturing a cylindrical secondary battery according to one embodiment of the present invention. [Figure 8] This is a perspective view illustrating only the fixing fixtures used in a method for manufacturing a cylindrical secondary battery according to one embodiment of the present invention. [Modes for carrying out the invention]

[0041] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. However, the present invention can be realized in a variety of different forms and is not limited or restricted by the embodiments described below.

[0042] For the purpose of clearly describing the present invention, detailed descriptions of relevant prior art that are irrelevant to the description or that could obscure the gist of the invention have been omitted. In this specification, when assigning reference numerals to components in the drawings, the same or similar reference numerals are used for components that are the same or similar throughout the specification.

[0043] Furthermore, the terms and words used in this specification and the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather should be interpreted in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors may appropriately define the concepts of terms in order to best describe their invention.

[0044] One Embodiment - Cylindrical Secondary Battery and Method for Manufacturing a Cylindrical Secondary Battery Figure 3 is a perspective view illustrating a method for manufacturing a cylindrical secondary battery according to one embodiment of the present invention. Figure 4 is a front view of Figure 3.

[0045] <Manufacturing method for cylindrical secondary batteries> A method for manufacturing a cylindrical secondary battery 100 according to one embodiment of the present invention relates to a method for manufacturing a cylindrical secondary battery that includes a jelly roll type electrode assembly 110 formed by winding electrodes and separators. The electrode assembly can be formed by alternately arranging positive electrodes, separators, and negative electrodes. The electrode assembly is a jelly roll type electrode assembly 110 having a form in which electrodes and separators are alternately arranged and wound together. Such a jelly roll type electrode assembly 110 can be an electrode winding in which one or more positive electrodes, one or more negative electrodes, and one or more separators are wound together.

[0046] Furthermore, a method for manufacturing a cylindrical secondary battery according to one embodiment of the present invention may include a current collector arrangement step and a current collector welding step.

[0047] The current collector placement step can be the step of placing a current collector 130, which has a through-hole 131 formed therein, on the end of the jelly roll type electrode assembly 110 in the direction of the winding center axis X. Figure 3 shows the current collector 130 placed on the upper end of the jelly roll type electrode assembly 110. The current collector 130 can have a disc shape with a through-hole 131 formed therein. The current collector 130 can be made of metal.

[0048] Referring to Figure 3, a single current collector through-hole 131 can have four edges. It can have two curved angles and two straight angles. The two curved angles formed in a circular shape can be an inner angle and an outer angle. The two angles formed by straight lines can be two straight angles connecting the ends of the inner angle and the outer angle to each other.

[0049] In the current collector placement process, the current collector 130 can be placed on the end of the jelly roll type electrode assembly 110 such that the curved portion of the upper end of the electrode included in the jelly roll type electrode assembly 110 and the curved portion of the corner 131-1 of the current collector penetration opening correspond to each other.

[0050] The welding process for the current collector can be a process of joining the jelly roll type electrode assembly 110 and the current collector 130 by welding. In particular, the electrodes in the jelly roll type electrode assembly 110 and the current collector 130 can be electrically connected by welding. Subsequently, the current collector 130 and the jelly roll type electrode assembly 110 joined to it can be housed in a cylindrical can (not shown) to manufacture a cylindrical secondary battery 100. The current collector 130 can be joined to the terminals of the cylindrical can and electrically connected to the terminals of the cylindrical can. The electrodes of the jelly roll type electrode assembly 110 joined to the current collector 130 can be either positive or negative electrodes.

[0051] In a method for manufacturing a cylindrical secondary battery according to one embodiment of the present invention, the welding process for the current collector allows welding of the jelly roll type electrode assembly 110 and the corner 131-1 of the current collector through-hole in the circumferential direction. The corner 131-1 of the current collector through-hole is formed in a curved shape corresponding to the electrode shape of the circular electrode assembly, and welding can be performed in the circumferential direction by welding along the corner 131-1 of the current collector through-hole.

[0052] Specifically, the welding process for the current collector can weld the electrodes included in the jelly roll-type electrode assembly 110 to the corner 131-1 of the current collector penetration. Here, the welding can be performed by laser welding. Figures 3 and 4 illustrate how the laser L is irradiated onto the corner of the current collector penetration to perform welding.

[0053] By having these features, the present invention enables welding between the current collector 130 and the jelly roll type electrode assembly 110 without any gaps, prevents welding defects, and allows welding of the current collector 130 and the jelly roll type electrode assembly 110 with excellent quality.

[0054] Normally, the height of the wound jelly roll-type electrode assembly 110 increases from the inside to the outside (i.e., radially) relative to the winding center axis X, which creates a gap between the current collector 130 and the jelly roll-type electrode assembly 110. Conventionally, welding defects occurred when welding the body of the current collector 130 and the electrode assembly due to such a gap. Furthermore, conventionally, welding was performed on the upper surface of the current collector 130, and this method, in particular, reduced the positional accuracy of the welding (see Figure 2).

[0055] However, in the manufacturing method of a cylindrical secondary battery according to one embodiment of the present invention, welding is performed in the circumferential direction from the position of the corner 131-1 portion of the current collector penetration opening, thereby significantly improving the positional accuracy of the welding.

[0056] Furthermore, in the manufacturing method of the cylindrical secondary battery of the present invention, welding can be performed in the welding process of the current collector by using a laser scanner with a seam tracking function to sense the corners 131-1 of the current collector penetration opening formed in the circumferential direction. In this case, the positional accuracy of the welding can be further improved.

[0057] Furthermore, welding can be performed without any gaps between the current collector 130 and the electrode assembly along the circumferential welding route. Also, welding with a constant welding depth can be achieved. Therefore, a strong welded joint can be achieved without welding defects.

[0058] In the welding process for the current collector, the corner 131-1 of the current collector through-hole where welding is performed can be the outermost corner among the corners that form the inner circumference of the current collector through-hole 131.

[0059] Of course, when welding in the circumferential direction, both the inner and outer corners, which are formed by curves, are possible for welding the four corners of the through-hole. However, since the outer corner is longer in the circumferential direction, the weld length can be longer in the case of the outer corner. In this case, a stronger bond can be achieved.

[0060] Furthermore, in the welding process of the current collector in the method for manufacturing a cylindrical secondary battery according to one embodiment of the present invention, when laser welding the jelly roll type electrode assembly 110 and the corner 131-1 of the current collector penetration opening in the circumferential direction, welding can be performed while drawing a predetermined welding pattern 150. This welding pattern 150 can be zigzag in shape, or circular in shape, and may include at least one of these two.

[0061] When performing simple line welding, the molten area of ​​the weld may be small. Therefore, in order to melt over a wider area and fill the gap over a wider area, welding can be performed while drawing a predetermined zigzag 150 or circular welding pattern.

[0062] When welding circumferentially along the corner 131-1 of the current collector penetration, line welding may result in a somewhat narrow welding area. However, by welding while creating such a pattern, a wider welding area can be achieved. Therefore, the welding quality can be improved and made stronger.

[0063] Furthermore, in this case, a wider area can be joined with less energy than in conventional methods, forming lower resistance. This reduces not only the ease of welding but also the resistive heat generated in the current collector, maximizing the high performance and efficiency of the battery.

[0064] Specifically, referring to Figures 3 and 4, the welding pattern 150 is a zigzag pattern, and the width h of the zigzag pattern can be at least half the thickness t of the current collector 130. By performing welding in this manner, a more suitable weld can be achieved, taking into account the thickness of the current collector 130.

[0065] Figure 7 is a perspective view illustrating how the fixing device 170 is used in a method for manufacturing a cylindrical secondary battery according to one embodiment of the present invention. Figure 8 is a perspective view illustrating only the fixing device 170 used in a method for manufacturing a cylindrical secondary battery according to one embodiment of the present invention.

[0066] Referring to Figures 7 and 8, the welding step of the current collector in the method for manufacturing a cylindrical secondary battery according to one embodiment of the present invention can be performed with at least one of the jelly roll-type electrode assembly 110 and the current collector 130 fixed using a fixing device 170.

[0067] In particular, the fixing device 170 may include a pressurizing surface 171 and a guide surface 172. The pressurizing surface 171 may have a disc-shaped plate form and be configured to pressurize the upper surface of the current collector 130. The guide surface 172 may be a portion that extends inclined from the periphery of the pressurizing surface 171.

[0068] A welding hole 171-1 is formed on the pressurized surface 171 at a position corresponding to the corner 131-1 of the current collector penetration, allowing welding to be performed. Because this welding hole 171-1 is formed on the guide surface 172, the corner 131-1 of the current collector penetration and the jelly roll electrode assembly 110 can be laser-welded stably and precisely at the correct position. The laser L for welding can penetrate the welding hole 171-1 to perform the welding.

[0069] <Cylindrical rechargeable battery> When a secondary battery is manufactured according to the method for manufacturing a cylindrical secondary battery according to one embodiment of the present invention described above, a cylindrical secondary battery 100 according to one embodiment of the present invention described below can be manufactured. When describing the secondary battery according to one embodiment of the present invention below, we will omit as much as possible any content that overlaps with the content described in the above manufacturing method, and will focus on explaining the differences.

[0070] Referring to Figures 3 and 4, a cylindrical secondary battery 100 according to one embodiment of the present invention may include a jelly roll electrode assembly 110 and a current collector 130. The jelly roll electrode assembly 110 can be formed by winding electrodes and a separator. The current collector 130 may have a through-hole and be welded to the end of the jelly roll electrode assembly 110 in the direction of the winding center axis X. The jelly roll electrode assembly 110 is then welded circumferentially to the corner (edge) 131-1 of the current collector through-hole. The jelly roll electrode assembly 110 and the corner 131-1 of the current collector through-hole may be joined by laser welding.

[0071] The cylindrical secondary battery 100 formed in this manner can be welded together with the current collector 130 and the jelly roll-type electrode assembly 110 at a predetermined welding depth without any gaps. This allows for a welded bond with excellent quality and strong bonding strength.

[0072] Specifically, in the cylindrical secondary battery 100 according to one embodiment of the present invention, the electrodes included in the jelly roll type electrode assembly 110 and the corner 131-1 of the current collector penetration opening can be welded together.

[0073] The welded corner 131-1 of the current collector through-hole can be the outermost corner among the corners forming the periphery of the current collector through-hole 131. The outer corner is welded, and a longer length of weld may be performed.

[0074] Furthermore, the circumferential laser welding of the jelly roll electrode assembly 110 and the corner 131-1 of the current collector penetration can be formed with a predetermined welding pattern 150. Such a welding pattern 150 may include at least one of a zigzag or circular pattern. In particular, if the welding pattern 150 is a zigzag pattern, the width h of the zigzag pattern may be at least half the thickness t of the current collector 130.

[0075] Such zigzag or circular welding patterns allow for melting over a wider area, resulting in a weld with gaps filled over a larger area. As a result, the cylindrical battery according to the present invention can be a battery with maximized high performance and high efficiency.

[0076] Other embodiments - Cylindrical secondary battery and method for manufacturing a cylindrical secondary battery Figure 5 is a perspective view illustrating a current collector and a jelly roll-type electrode assembly of a cylindrical secondary battery according to another embodiment of the present invention. Figure 6 is a perspective view showing a magnified view of the slit-shaped through-hole of the current collector shown in Figure 5.

[0077] Other embodiments of the present invention differ from the cylindrical secondary battery and the method for manufacturing the cylindrical secondary battery according to one embodiment of the present invention in that the shape of the current collector is different.

[0078] We will omit as much as possible the content common to one embodiment and describe the other embodiments focusing on the differences. In other words, it is self-evident that if content not explained in the other embodiments is necessary, it can be supplemented by the content of the first embodiment.

[0079] <Manufacturing method for cylindrical secondary batteries> Referring to Figures 5 and 6, a method for manufacturing a cylindrical secondary battery 200 according to another embodiment of the present invention includes a current collector arrangement step and a current collector welding step, similar to one embodiment. However, the current collector 130 may have a slit-shaped through-hole 132. This allows the current collector welding step to laser weld the jelly roll electrode assembly 110 to the corner 132-1 of the slit-shaped through-hole.

[0080] Even when the current collector 130 has a slit-shaped through-hole 132, a single current collector through-hole can have four angles. It can have two curved angles and two straight angles. These can be an inner angle and an outer angle formed by a circular curve, and two straight angles connecting the inner angle and the outer angle to each other.

[0081] However, if the current collector 130 has a slit-shaped through-hole, the lengths of the curved inner and outer angles can be similar, and the inner and outer angles can be located adjacent to each other. Therefore, during laser welding, the welding length for welding the inner angle and the welding length for welding the outer angle can be similar. As a result, there can be little difference in terms of welding strength between the two cases of welding the inner and outer angles. This can be advantageous in that it increases the options for which angle to use for welding.

[0082] Referring to Figure 6, in the welding process of the current collector, when laser welding the jelly roll-type electrode assembly 110 and the corner 132-1 of the slit-shaped through-hole in the circumferential direction, welding can be performed by drawing a predetermined welding pattern 150. The welding pattern 150 may include at least one of the following: a zigzag pattern or a circular pattern.

[0083] When the current collector 130 has a slit-shaped through-hole, the inner and outer corners are located adjacent to each other. This offers the advantage of being able to weld both the inner and outer corners when welding while drawing the predetermined welding pattern 150. In this case, the welding strength can be further improved.

[0084] On the other hand, referring to Figure 5, the current collector 130 can have a multi-purpose hole 133 formed in the center, which has a circular, penetrating shape. The multi-purpose hole 133 can serve as a means of injecting electrolyte or discharging gas.

[0085] <Cylindrical rechargeable battery> When a secondary battery is manufactured according to the method for manufacturing a cylindrical secondary battery according to another embodiment of the present invention described above, a cylindrical secondary battery 200 according to another embodiment of the present invention, as described below, can be manufactured. When describing the secondary battery according to another embodiment of the present invention below, we will omit as much as possible any content that overlaps with the content described in the above manufacturing method and will focus on explaining the differences.

[0086] Referring to Figure 5, a cylindrical secondary battery 200 according to another embodiment of the present invention may also include a jelly roll-type electrode assembly 110 and a current collector 130.

[0087] However, in this case, the current collector 130 has a slit-shaped through-hole 132, and the jelly roll-type electrode assembly 110 and the corner 132-1 of the slit-shaped through-hole are joined by laser welding. Here, the welding may be performed on the curved outer corner 132-1 of the slit-shaped through-hole, or on the inner corner, or on both the inner and outer corners. In this case, a welded joint of excellent quality can be obtained.

[0088] Specifically, when the current collector 130 has a slit-shaped through-hole 132, the lengths of the curved inner and outer angles can be similar, and the inner and outer angles can be located adjacent to each other. Therefore, the welding strength can be similar whether the inner angle is welded or the outer angle is welded. Thus, even when the inner angle is welded, a relatively strong bond can be achieved. Furthermore, the welding strength can be stronger when both the inner and outer angles are welded.

[0089] Furthermore, in the cylindrical secondary battery 200 according to other embodiments of the present invention, the circumferential laser welding of the jelly roll electrode assembly 110 and the corner 132-1 of the slit-shaped through-hole can be performed with a predetermined welding pattern 150. Such a welding pattern 150 may include at least one of a zigzag or circular pattern.

[0090] When the current collector 130 has a slit-shaped through-hole 132, the inner corner and outer corner are located adjacent to each other, so the predetermined welding pattern 150 may be formed spanning both the inner corner and the outer corner. In this case, the welding strength can be significantly increased.

[0091] On the other hand, the current collector 130 may have a multi-purpose hole 133 formed in the center, which is circular and penetrates through the material. This multi-purpose hole 133 can serve the purpose of injecting electrolyte or discharging gas.

[0092] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible by persons with ordinary skill in the art to which the present invention pertains, within the equivalent scope of the technical concept of the present invention and the claims described below. [Explanation of Symbols]

[0093] 100 cylindrical rechargeable batteries 110 Jelly Roll Type Electrode Assembly 130 Current collector 131 Current collector through-hole 131-1 Corner of the current collector through-hole 132 Slit-shaped through-hole 132-1 Corner of a slit-shaped through-hole 133 Multipurpose Hall 150 welding patterns 170 Fixtures 171 Pressure surface 172 Guide surface 171-1 Welding Hole L Laser X Winding center axis

Claims

1. A method for manufacturing a cylindrical secondary battery, which includes a jelly roll-type electrode assembly formed by winding electrodes and a separator, A current collector arrangement step involves placing a current collector, which has a through-hole formed at the end of the jelly roll type electrode assembly in the direction of the winding center axis, The process includes a welding step for the current collector, in which the jelly roll-type electrode assembly and the current collector are joined by welding. The welding process for the current collector is as follows: A method for manufacturing a cylindrical secondary battery, comprising welding the jelly roll-type electrode assembly and the corner (edge) of the current collector penetration opening in the circumferential direction.

2. In the process of arranging the current collector, A method for manufacturing a cylindrical secondary battery according to claim 1, wherein the current collector is placed on the end of the jelly roll electrode assembly such that the curved portion of the electrode end included in the jelly roll electrode assembly and the curved portion of the corner (edge) of the current collector penetration opening are in corresponding positions.

3. The welding process for the current collector is as follows: A method for manufacturing a cylindrical secondary battery according to claim 2, wherein the electrode included in the jelly roll-type electrode assembly and the corner of the current collector penetration opening are welded together.

4. In the welding process of the current collector, The method for manufacturing a cylindrical secondary battery according to claim 1, wherein the corner of the current collector penetration opening where welding is performed is the outermost corner among the corners forming the periphery of the current collector penetration opening.

5. The welding process for the current collector is as follows: A method for manufacturing a cylindrical secondary battery according to claim 1, performed by laser welding.

6. In the welding process of the current collector, A method for manufacturing a cylindrical secondary battery according to claim 5, wherein when laser welding the corners of the jelly roll-type electrode assembly and the current collector penetration opening in the circumferential direction, the welding is performed while drawing a predetermined welding pattern.

7. In the welding process of the current collector, The method for manufacturing a cylindrical secondary battery according to claim 6, wherein the welding pattern includes at least one of a zigzag or circular pattern.

8. The current collector has a slit-shaped through-hole, The welding process for the current collector is as follows: A method for manufacturing a cylindrical secondary battery according to claim 1, wherein the corners of the jelly roll-type electrode assembly and the slit-shaped through-hole are laser-welded.

9. In the welding process of the current collector, A method for manufacturing a cylindrical secondary battery according to claim 8, wherein when laser welding the corners of the jelly roll-type electrode assembly and the slit-shaped through-hole in the circumferential direction, the welding is performed while drawing a predetermined welding pattern.

10. In the welding process of the current collector, The method for manufacturing a cylindrical secondary battery according to claim 9, wherein the welding pattern includes at least one of a zigzag or circular pattern.

11. The aforementioned welding pattern is a zigzag pattern. The method for manufacturing a cylindrical secondary battery according to claim 7 or claim 10, wherein the width h of the zigzag pattern is 1 / 2 or more of the thickness t of the current collector.

12. In the welding process of the current collector, A method for manufacturing a cylindrical secondary battery according to claim 1, wherein a laser scanner including a seam tracking function is used to detect the corners of the current collector through-holes formed in the circumferential direction.

13. The current collector includes, A method for manufacturing a cylindrical secondary battery according to claim 1, wherein a multi-purpose hole is formed for injecting electrolyte or discharging gas.

14. The welding process for the current collector is as follows: A method for manufacturing a cylindrical secondary battery according to claim 1, wherein at least one of the jelly roll electrode assembly and the current collector is fixed using fixing devices.

15. The aforementioned fixing device is, A pressurizing surface that pressurizes the upper surface of the current collector, This includes a guide surface that extends inclined from the periphery of the pressurizing surface, The method for manufacturing a cylindrical secondary battery according to claim 14, wherein a welding hole is formed on the pressurized surface at a position corresponding to the corner of the current collector penetration opening, in which welding is performed.

16. A jelly roll-type electrode assembly is formed by winding electrodes and a separator together, It includes a current collector having a through-hole formed therein, which is welded to the end of the jelly roll type electrode assembly in the direction of the winding center axis, The jelly roll-type electrode assembly is welded circumferentially to the corner (edge) of the current collector penetration opening, in a cylindrical secondary battery.

17. The cylindrical secondary battery according to claim 16, wherein the electrode included in the jelly roll-type electrode assembly and the corner of the current collector penetration opening are welded together.

18. The cylindrical secondary battery according to claim 16, wherein the welded corner of the current collector through-hole is the outermost corner among the corners forming the periphery of the current collector through-hole.

19. The cylindrical secondary battery according to claim 16, wherein the jelly roll-type electrode assembly and the corner (edge) of the current collector penetration opening are joined by laser welding.

20. The cylindrical secondary battery according to claim 19, wherein the circumferential laser welding of the jelly roll-type electrode assembly and the corner of the current collector penetration opening is formed in a predetermined welding pattern.

21. The cylindrical secondary battery according to claim 20, wherein the welding pattern includes at least one of a zigzag or circular pattern.

22. The current collector has a slit-shaped through-hole, The cylindrical secondary battery according to claim 16, wherein the jelly roll-type electrode assembly and the corner of the slit-shaped through-hole are joined by laser welding.

23. The cylindrical secondary battery according to claim 22, wherein the circumferential laser welding of the jelly roll-type electrode assembly and the corner of the slit-shaped through-hole is performed in a predetermined welding pattern.

24. The cylindrical secondary battery according to claim 23, wherein the welding pattern includes at least one of a zigzag or circular pattern.

25. The aforementioned welding pattern is a zigzag pattern. The cylindrical secondary battery according to claim 21 or claim 24, wherein the width h of the zigzag pattern is 1 / 2 or more of the thickness t of the current collector.

26. The current collector includes, A cylindrical secondary battery according to claim 16, wherein a multi-purpose hole is formed for injecting electrolyte or discharging gas.

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