Apparatus and method for manufacturing secondary battery and secondary battery manufactured thereby

Abstract

The present invention relates to an apparatus and a method for manufacturing a secondary battery, and a secondary battery manufactured thereby, and more particularly, to an apparatus and a method for manufacturing a secondary battery, which, when connecting an electrode tab and an electrode lead of an electrode assembly by welding, does not cause defects such as damage or breakage of the electrode tab, and prevents the occurrence of welding defects such as weak welding or over-welding, thereby improving the reliability of the secondary battery. The present invention relates to an apparatus and a method for manufacturing a secondary battery and a secondary battery manufactured thereby to achieve excellent quality.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Korean Patent Application No. 10-2022-0093537 filed on Jul. 27, 2022 and Korean Patent Application No. 10-2023-0093435 filed on Jul. 18, 2023, which are hereby incorporated by reference in their entirety. Technical Field

[0003] The present invention relates to an apparatus and method for manufacturing a secondary battery and a secondary battery manufactured thereby. The present invention relates to an apparatus and method for manufacturing a secondary battery, which can achieve excellent quality by preventing defects such as damage or disconnection of the electrode tabs and welding defects such as weak welding or over-welding from occurring when connecting electrode tabs and electrode leads of an electrode assembly by welding, and a secondary battery manufactured thereby. Background Art

[0004] In recent years, due to the depletion of fossil fuels, the price of energy has increased, concerns about environmental pollution have increased, and the demand for eco-friendly alternative energy is becoming an indispensable factor in future life. Therefore, research on various power generation technologies such as solar energy, wind energy, and tidal energy is continuing, and power storage devices such as batteries for more efficient use of generated electrical energy are also attracting attention.

[0005] In addition, as technology develops and demand for electronic mobile devices and electric vehicles using batteries increases, demand for batteries as energy sources is rapidly increasing. Therefore, many studies have been conducted on batteries that can meet various needs.

[0006] Secondary batteries have received much attention as energy sources in various products such as mobile devices and electric vehicles. These secondary batteries are excellent energy sources that can replace the use of existing products that use fossil fuels, and because secondary batteries do not produce byproducts due to energy use, they are attracting attention as environmentally friendly energy sources.

[0007] Figure 1 is a side view illustrating a process of connecting an electrode tab and an electrode lead using a method of manufacturing a secondary battery according to the related art.

[0008] refer to Figure 1 In the method of manufacturing a secondary battery according to the prior art, a pre-welding process is first performed (see Figure 1 ① in the figure), and then perform the main welding process (see Figure 1 ② in the figure to perform the process of connecting the electrode tab to the electrode lead.

[0009] Pre-welding process (see Figure 1①) in the figure is a process of gathering a plurality of electrode tabs extending from the electrodes of the electrode assembly to join the electrode tabs to each other by ultrasonic welding. As a result, an electrode tab assembly can be formed. Pre-welding is a method of arranging a plurality of electrode tabs between an upper welding head and a lower anvil to apply ultrasonic vibration B to the welding head while being physically pressed by the welding head and the anvil.

[0010] Main welding process (see Figure 1 ②) in the figure is a process of joining the electrode lead to the assembled electrode tab assembly. In this process, laser welding is performed using a laser welding machine to join the electrode tab to the electrode lead.

[0011] This method according to the prior art has the following problems. First, since the pre-welding method is a method of applying physical pressure to the electrode tab using a horn and an anvil and applying ultrasonic vibration to the horn, there is a problem of inevitably damaging the electrode tab. In addition, during ultrasonic welding, there is a problem of welding defects (such as weak welding and over-welding) due to abnormal welding conditions (such as energy, power, welding time, and applied pressure). In addition, there are also problems of welding defects caused by horizontal deviation or abnormal stacking of the horn and anvil during welding and defects such as disconnection of the electrode tab.

[0012] Furthermore, during ultrasonic welding, there are inevitable problems that occur due to the use of the horn and the anvil. Specifically, there is a problem of replacement cycle management due to the wear of the horn and the anvil, and there is a risk of disconnection of the electrode tab due to the edge curvature radius (edge ​​R) of the horn and the anvil. Furthermore, there is a risk of welding defects due to poor conditions of the ultrasonic welding machine.

[0013] In addition, during main welding, when the electrode lead overlaps the electrode tab, there is a problem that the edge of the electrode lead scratches the electrode tab, causing damage to the electrode tab, and during laser welding, there is a problem that the electrode tab is scratched by the laser mask jig. Summary of the invention

[0014] Technical issues

[0015] The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to provide a device and method for manufacturing a secondary battery and a secondary battery manufactured thereby, which can achieve excellent quality when an electrode tab and an electrode lead of an electrode assembly are connected by welding, without defects such as damage or disconnection of the electrode tab, and can prevent welding defects such as weak welding or over-welding from occurring.

[0016] Technical Solution

[0017] According to a method for manufacturing a secondary battery of the present invention, the method welds a plurality of electrode tabs to an electrode lead, the plurality of electrode tabs extending from one end of an electrode assembly formed by stacking electrodes and separators, the method comprising: a process (a) of preparing an adhesive tape having a desired size and shape; a process (b) of gathering the plurality of electrode tabs to form an electrode tab stack; a process (c) of bonding the electrode tab stack with the adhesive tape; and a process (d) of welding the bonded electrode tab stack to the electrode lead.

[0018] The method may further include a cutting process (c-1) of cutting one end of the bonded electrode tab stack between the process (c) and the process (d).

[0019] The process (a) of preparing the adhesive tape may include a process of cutting the adhesive tape into a desired size and shape to prepare the adhesive tape.

[0020] In the process (b) of forming the electrode tab stack, a plurality of electrode tabs may be pressed or guided from upper and lower sides of the electrode tabs to gather the electrode tabs, thereby forming the electrode tab stack.

[0021] In the taping process (c), a tape may be attached to each of both sides of the electrode tab stack based on a width direction of the electrode tab stack.

[0022] In the taping process (c), the tape may be attached to surround the top surface, the side surface, and the bottom surface of the electrode tab stack.

[0023] In the taping process (c), the tape may not be attached to portions on the top and bottom surfaces of the electrode tab stack to which the electrode leads are to be welded.

[0024] In the process (c) of bonding with tape, the tape may be attached to each of both sides of the electrode tab stack based on the width direction of the electrode tab stack, wherein the tape may be attached to the electrode tab stack to form an excess portion that protrudes further outward from the side end of the electrode tab stack in the width direction.

[0025] In the taping process (c), the excess portion may have a shape in which a portion and another portion of the tape disposed outside the side end of the electrode tab stack in the width direction face each other to be engaged with each other.

[0026] Process (b) and process (c) can be performed simultaneously.

[0027] In the process (d) of welding the electrode lead, the electrode tab stack and the electrode lead may be welded to each other by laser welding.

[0028] In the process (d) of welding the electrode leads, the electrode tab stack and the electrode leads are welded to each other while the excess portions are pulled toward both sides based on the width direction of the electrode tab stack, in a state where an excess portion provided on each side of both sides of the electrode tab stack is clamped using a clamping device.

[0029] According to the present invention, an apparatus for manufacturing a secondary battery, the apparatus welds a plurality of electrode tabs to an electrode lead, the plurality of electrode tabs extending from one end of an electrode assembly formed by stacking electrodes and separators, the apparatus comprising: a tape cutting unit configured to cut the tape into a desired size and shape; a tab guide configured to gather the plurality of electrode tabs to provide an electrode tab stack; a tape attaching machine configured to adhere the cut tape to the electrode tab stack; and a laser welding machine configured to weld the adhered electrode tab stack to the electrode lead.

[0030] The tape attaching machine may be configured to adhere the tape to the electrode tab stack, wherein the tape may be attached to surround a top surface, a side surface, and a bottom surface of the electrode tab stack.

[0031] The tape attaching machine may be configured to adhere the tape to the electrode tab stack, wherein the tape may be attached to the electrode tab stack to provide a surplus portion protruding outward from a side end of the electrode tab in a width direction.

[0032] The apparatus may further include a clamping device configured to pull excess portions disposed at both sides of the electrode tab stack toward both sides based on a width direction of the electrode tab stack.

[0033] The apparatus may further include a cutter configured to cut one end of the electrode tab stack adhered by the tape attaching machine.

[0034] A secondary battery according to the present invention includes: an electrode assembly provided by stacking electrodes and separators; a bag configured to accommodate the electrode assembly in an internal space; an electrode tab stack provided by gathering a plurality of electrode tabs extending from one end of the electrode assembly and disposed inside the bag; a tape configured to surround the electrode tab stack; and an electrode lead, one side of the electrode lead being connected to the electrode tab stack and the other side protruding to the outside of the bag.

[0035] An adhesive tape may be attached to each of both sides of the electrode tab stack based on a width direction of the electrode tab stack.

[0036] The tape may be attached to each of both sides of the electrode tab stack based on the width direction of the electrode tab stack, wherein the tape may include a surplus portion further protruding outward from a side end of the electrode tab stack in the width direction W.

[0037] The excess portion may have a shape in which a portion and another portion of the tape disposed outside the side end of the electrode tab stack in the width direction W face each other to be engaged with each other.

[0038] Beneficial Effects

[0039] In an apparatus and method for manufacturing a secondary battery and a secondary battery manufactured thereby, when electrode tabs and electrode leads of an electrode assembly are connected by welding, defects such as damage or disconnection of the electrode tabs do not occur, and welding defects such as weak welding or over-welding are prevented from occurring, thereby achieving excellent quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a side view illustrating a process of connecting an electrode tab and an electrode lead using a method for manufacturing a secondary battery according to the related art.

[0041] Figure 2 is a side view showing a process of connecting an electrode tab to an electrode lead by the method for manufacturing a secondary battery according to Embodiment 1 of the present invention.

[0042] Figure 3 is a side view showing a process of connecting an electrode tab to an electrode lead according to a modified example of Embodiment 1 of the present invention.

[0043] Figure 4 is a perspective view showing a state where a tape is attached to an electrode tab stack.

[0044] Figure 5 is a perspective view showing a state in which one end of the electrode tab stack is cut.

[0045] Figure 6 is a perspective view showing the internal configuration of a secondary battery according to Embodiment 2 of the present invention.

[0046] Figure 7 is a side view showing a process of connecting an electrode tab to an electrode lead by a method for manufacturing a secondary battery according to Embodiment 3 of the present invention.

[0047] Figure 8 is a perspective view showing a state in which the tape according to Embodiment 3 of the present invention is attached to an electrode tab stack.

[0048] Fig. 9: is a cross-sectional view showing the principle of generating the excess portion of the adhesive tape according to the third embodiment of the present invention.

[0049] Fig.10 is a perspective view showing a state in which one end of an electrode tab stack according to Embodiment 3 of the present invention is cut.

[0050] Fig.11 is a perspective view showing the internal configuration of a secondary battery according to Embodiment 4 of the present invention. DETAILED DESCRIPTION

[0051] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. However, the present invention can be implemented in several different forms and is not limited or constrained by the following examples.

[0052] In order to explain the present invention clearly, the detailed description of the related known technology that is irrelevant to the description or may unnecessarily make the main idea of ​​the present invention difficult to understand is omitted, and in this specification, reference numerals are added to the components in each drawing. In this case, the same or similar reference numerals are assigned to the same or similar elements throughout the specification.

[0053] Furthermore, the terms or words used in the specification and claims should not be restrictively interpreted as ordinary meanings or dictionary-based meanings, but should be interpreted as meanings and concepts consistent with the scope of the present invention based on the principle that the inventor can appropriately define the concepts of the terms to best describe and interpret his or her invention.

[0054] [Example 1]

[0055] Figure 2 is a side view showing a process of connecting an electrode tab to an electrode lead by the method for manufacturing a secondary battery according to Embodiment 1 of the present invention. Figure 3 is a side view showing a process of connecting an electrode tab to an electrode lead according to a modified example of Embodiment 1 of the present invention. Figure 4 is a perspective view showing a state where a tape is attached to an electrode tab stack. Figure 5 is a perspective view showing a state in which one end of the electrode tab stack is cut.

[0056] refer to Figure 2, the method for manufacturing a secondary battery according to embodiment 1 of the present invention may involve a method for manufacturing a secondary battery in which a plurality of electrode tabs 20 are welded to an electrode lead 40, and the plurality of electrode tabs 20 extend from one end of an electrode assembly formed by stacking electrodes and separators. The electrode assembly 10 may be formed by alternately stacking electrodes and separators, and the electrode tab 20 may be a metal tab connected to each electrode and protruding from one side of the electrode. Therefore, the plurality of electrode tabs 20 may have a structure extending from one end of the electrode assembly 10. The stack in which the plurality of electrode tabs 20 are combined may be coupled to the electrode lead 40 to manufacture a secondary battery.

[0057] The method for manufacturing a secondary battery according to Embodiment 1 of the present invention may include a process of preparing a tape (a), a process of forming an electrode tab stack (b), a process of bonding with the tape (c), and a process of welding an electrode lead (d).

[0058] The process (a) of preparing the adhesive tape may be a process of preparing the adhesive tape 31 having a desired size and shape. Figure 2 (a) shows the process. In this process, the tape 31 may be cut using a tape cutting unit (not shown) that cuts the tape 31. The tape 31 may be prepared by cutting the tape 31 into a desired size and shape using the tape cutting unit.

[0059] Figure 2 (a) shows the tape 31 after the cutting is completed. Here, the tape 31 having a desired size and shape may mean that the tape 31 has a size and shape required for attaching the tape 31 to bundle the electrode tabs 20 in a state where the electrode tabs 20 are gathered together. The process (a) of cutting and preparing the tape 31 may not necessarily be performed first, and may be performed in any process as long as the process is performed before the process (c) of bonding with the tape, which will be described below.

[0060] The process (b) of forming the electrode tab stack may be a process of forming the electrode tab stack 30 by gathering a plurality of electrode tabs 20 . Figure 2 (b) shows the process. The process may be performed using a tab guide 110 that gathers a plurality of electrode tabs 20 to form an electrode tab stack 30. Figure 2 (b), the tab guide 110 may move from the upper and lower portions of the electrode tab 20 toward the electrode tab 20 to gather the electrode tabs 20. The tab guide 110 may press or guide the plurality of electrode tabs 20 from the upper and lower sides of the electrode tab 20 to gather the electrode tabs 20, thereby forming an electrode tab stack 30.

[0061] In addition, the end of the tab guide 110 may have a rounded shape. Such a shape may prevent the electrode tab 20 from being damaged when the tab guide 110 vertically applies pressure to the plurality of electrode tabs 20 to gather the electrode tabs 20.

[0062] The process (c) of bonding with tape may be a process of bonding the tape 31 to the electrode tab stack 30. This process may be a process of maintaining the stack 30 in which the electrode tabs are gathered in a stable shape without moving or being disturbed. This process may be performed to gather the electrode tabs 20 for welding in a subsequent welding process of the electrode lead 40.

[0063] Figure 2 (c) shows the process. In addition, Figure 4 FIG. 2 shows a state where the tape 31 is attached to the electrode tab stack 30 in process (c). Figure 2 (c) and Figure 4 , in the process (c) of bonding with tape, the tape 31 may be attached to each of the two sides of the electrode tab stack 30 based on the width direction W of the electrode tab stack 30. In addition, the tape 31 may be attached to both sides, and may also be attached while surrounding the top surface, side surface, and bottom surface of the electrode tab stack 30. In order to gather the electrode tabs 20, the electrode tabs 20 may be attached in a tight state with tension applied, or may be attached with an appropriate strength without being too tight. Reference Figure 4 , the tape 31 may be attached to a horizontal portion of a portion where the electrode tabs 20 are gathered, and may also be partially attached to an inclined portion extending from the horizontal portion toward the electrode assembly.

[0064] In the process (c) of bonding with tape, the tape 31 may be attached to the top surface or the bottom surface of the electrode tab stack 30, but may not be attached to the portion to which the electrode lead 40 is to be welded. As described above, the welding area A to which the electrode lead 40 is welded may be formed in the portion to which the tape 31 is not attached (see Figure 6 ). Since the portion where the tape 31 is provided is a surface not suitable for welding, the tape 31 may not be attached to the surface to be welded. When attaching the tape 31, the tape attaching machine 120 may be used to adhere the cut tape 31 to the electrode tab stack 30.

[0065] Here, the basic function of the tape attaching machine 120 may be to attach the cut tape 31 to the electrode tab 20, but the tape attaching machine 120 may also be configured to have a function of cutting the tape 31. In this case, the tape attaching machine 120 may also be used as a tape cutting unit. When the tape attaching machine 120 having the function of a tape cutting unit is used, the operation may be simplified and efficient. That is, after completing the cutting of the tape 31, the user may keep the tape 31 as it is without moving to another location, and then the tape may be attached to the electrode tab 20 to achieve significantly efficient operation.

[0066] Processes (b) and (c) may be performed separately, but may also be performed together. That is, if process (b) of forming the electrode tab stack and process (c) of bonding with tape are performed simultaneously, the process is more efficient and effective. Figure 3 As shown in (c), the tab guide 110 may press the electrode tabs 20, gather the electrode tabs 20, and fix the electrode tabs 20, and then the tape attaching machine 120 may attach the tape 31 to the gathered electrode tab stack 30 to achieve more precise tape bonding.

[0067] The process (d) of welding the electrode tab stack and the electrode lead may be a process of welding the electrode tab stack 30 and the electrode lead 40, which are overlapped with each other and bonded by the tape, using a welding machine. The process may be a process of joining the electrode tab stack 30 to the electrode lead 40 by welding. In addition, specifically, the process (d) of welding the electrode lead 40 may be a process of laser welding the electrode tab stack 30 and the electrode lead 40. Figure 2 (d) shows the process. The process may be performed using a laser welding machine 130 , which is a device that irradiates welding laser to the electrode tab stack 30 and the electrode lead 40 .

[0068] Figure 6 FIG. 4 shows a state where the electrode lead 40 is joined to the electrode tab stack 30 by laser welding. Figure 6 , the welding area A where the laser welding is performed may be an area where the adhesive tape 31 is not attached. Figure 6 As shown, the welding area A may be the central area of ​​the top surface of the electrode tab stack 30. Alternatively, the electrode lead 40 is not limited to being welded to the top surface of the electrode tab stack 30, but may also be welded to the bottom surface of the electrode tab stack 30.

[0069] As described above, in the apparatus and method for manufacturing a secondary battery according to Embodiment 1 of the present invention, unlike the pre-welding method according to the prior art, the tape 31 can be used to manufacture a secondary battery without damaging the electrode tab 20. In addition, since ultrasonic welding is not performed, problems such as welding defects caused by ultrasonic welding can be fundamentally solved. For example, welding defects caused by horizontal deviation or abnormal stacking of the welding head and the anvil during welding and disconnection defects of the electrode tab 20 may not occur. In addition, since ultrasonic welding is not used, various problems caused by using an ultrasonic welding machine may not occur.

[0070] When the method of gathering the electrode tabs 20 using the tape 31 according to Embodiment 1 of the present invention is used, the electrode tabs 20 can be gathered quickly and efficiently to effectively perform the main welding of the electrode lead 40 and the electrode tabs 20. In addition, the electrode tabs 20 can be gathered to well secure the length margin of the electrode tabs 20.

[0071] In addition, during the main welding process, when the electrode lead 40 overlaps the electrode tab 20, the problem of the edge of the electrode lead 40 piercing the electrode tab 20 and damaging the electrode tab 20 can be reduced. Since the tape 31 covers and protects the surface of the electrode tab 20, even if the edge of the electrode lead contacts this portion, no damage occurs. In addition, the problem of piercing the electrode tab 20 caused by the laser mask jig during laser welding can be prevented.

[0072] Embodiment 1 of the present invention can be implemented in other modified forms. Figure 3 1 is a side view showing a process of connecting the electrode tab 20 to the electrode lead 40 according to a modified example of Embodiment 1 of the present invention.

[0073] refer to Figure 3 , in the modified example of Embodiment 1 of the present invention, a cutting process (c-1) may be further performed between processes (c) and (d).

[0074] Specifically, the cutting process (c-1) may be a process of cutting one end of the bonded electrode tab stack 30 . Figure 3 In the modified example of Embodiment 1 of the present invention, except that the cutting process (c-1) is further performed between the process (c) of bonding with tape and the process (d) of welding the electrode tab stack to the electrode lead, the remaining processes are the same as those of the embodiment 1 of the present invention. Figure 2 The cutting process (c-1) may be performed using a cutter 140 that cuts one end of the electrode tab stack 30 that has been bonded by the tape attaching machine 120 into an appropriate length.

[0075] When the electrode tab stack 30 is cut into an appropriate length, the efficiency of the laser welding operation can be improved by cutting the electrode tab stack 30 into an appropriate length for subsequent laser welding. In addition, there is an effect of being able to adjust the length of the electrode tab stack 30 to fit the size of the final product of the secondary battery. Even at this time, in the method of fixing the electrode tab 20 with the tape 31 of the present invention, the electrode tab 20 can be fixed, so that the electrode tab 20 is easily cut.

[0076] Figure 5 A state in which one end of the electrode tab stack is cut by the cutter 140 is shown. Figure 5 The shape of the electrode tab stack 30 is neatly cut along the cutting line L. Figure 5 In the embodiment, a central area of ​​the top surface of the electrode tab 20 to which the tape 31 is not attached may be a laser welding area A to which the electrode lead 40 is welded. Welding may be accurately performed on the welding area A after the cutting operation.

[0077] An apparatus for manufacturing a secondary battery may be required to perform the method for manufacturing a secondary battery according to Embodiment 1 of the present invention. The apparatus for manufacturing a secondary battery may be an apparatus for manufacturing a secondary battery that welds a plurality of electrode tabs 20 extending from one end of an electrode assembly formed by stacking electrodes and separators to an electrode lead 40.

[0078] The apparatus for manufacturing a secondary battery performing the method for manufacturing a secondary battery according to Embodiment 1 of the present invention may include a tape cutting unit (not shown), a tab guide 110 , a tape attaching machine 120 , and a laser welding machine 130 .

[0079] The tape cutting unit may be configured to cut the tape 31 into a desired size and shape. The tab guide 110 may be configured to gather a plurality of electrode tabs 20 to provide an electrode tab stack 30. The tape attaching machine 120 may be configured to bond the cut tape 31 to the electrode tab stack 30. In addition, the laser welding machine 130 may be configured to weld the bonded electrode tab stack 30 to the electrode lead 40. Here, the tape attaching machine 120 may also be used as a tape cutting unit. In addition, according to a modified example of embodiment 1 of the present invention, the apparatus for manufacturing a secondary battery may further include a cutter 140 for cutting one end of the electrode tab stack 30 to which bonding has been completed by the tape attaching machine 120.

[0080] [Example 2]

[0081] Figure 6 is a perspective view showing the internal configuration of a secondary battery according to Embodiment 2 of the present invention.

[0082] Embodiment 2 of the present invention is different from Embodiment 1 in that Embodiment 2 of the present invention relates to a secondary battery manufactured by the method for manufacturing a secondary battery according to Embodiment 1.

[0083] The contents repeated in Example 1 will be omitted as much as possible, and the differences will be emphasized when describing Example 2. Obviously, if necessary, the contents not described in Example 2 can be regarded as the contents of Example 1.

[0084] refer to Figure 6 , the secondary battery according to Embodiment 2 of the present invention may include an electrode assembly 10 , a pouch, an electrode tab stack 30 , an electrode lead 40 , and a tape 31 .

[0085] The electrode assembly 10 may be a stack provided by stacking electrodes and separators. A bag (not shown) may be configured to accommodate the electrode assembly 10 in an internal space. An electrode tab stack 30 may be provided by gathering a plurality of electrode tabs 20, which extend from one end of the electrode assembly 10 and are disposed inside the bag. The tape 31 may be configured to surround the electrode tab stack 30. Here, the tape 31 may be attached to each of the two sides of the electrode tab stack 30 based on the width direction W of the electrode tab stack 30.

[0086] When attached to both sides, the tape 31 may be attached while surrounding the top surface, the side surface, and the bottom surface of the electrode tab stack 30. In order to gather the electrode tabs 20, the electrode tabs 20 may be attached in a tight state with tension applied, or may be attached with an appropriate strength without being too tight. Based on the side view, the tape 31 may be attached to the horizontal portion of the portion where the electrode tabs 20 are gathered, and may also be partially attached to the inclined portion extending from the horizontal portion toward the electrode. That is, the thickness of the electrode tab stack 30 may be constant in the horizontal portion, but may become thicker in the inclined portion, and the tape 31 may be attached to a portion of the horizontal portion and the inclined portion.

[0087] In addition, the tape 31 may not be attached to the top and bottom surfaces of the electrode tab stack 30 to which the electrode lead 40 is to be welded. As described above, the welding region A to weld the electrode lead 40 may be formed in a portion to which the tape 31 is not attached (see Figure 6 ). Since the area to which the tape 31 is attached is a surface not suitable for welding, the tape 31 may not be attached to the surface to be welded.

[0088] The electrode lead 40 may have one side connected to the electrode tab stack 30 and the other side protruding to the outside of the bag (not shown). One side of the electrode lead 40 may be connected to the electrode tab stack 30 in the welding region A by laser welding. In addition, welding may not be performed in the region to which the lead film 41 is to be attached.

[0089] Furthermore, according to the various effects of the present invention described in the above-described Embodiment 1, the secondary battery according to Embodiment 2 of the present invention as described above can be a secondary battery having excellent quality.

[0090] [Example 3]

[0091] Figure 7 is a side view showing a process of connecting an electrode tab to an electrode lead by a method for manufacturing a secondary battery according to Embodiment 3 of the present invention. Figure 8 is a perspective view showing a state in which the tape according to Embodiment 3 of the present invention is attached to an electrode tab stack. Fig. 9 : is a cross-sectional view showing the principle of generating the excess portion of the adhesive tape according to Embodiment 3 of the present invention. Fig.10 is a perspective view showing a state in which one end of an electrode tab stack according to Embodiment 3 of the present invention is cut.

[0092] Embodiment 3 is different from Embodiments 1 and 2 in that, when attaching the tape to the electrode tab stack, the tape is attached such that an excess portion is disposed on each of both sides of the electrode tab.

[0093] The contents repeated with Embodiments 1 and 2 will be omitted as much as possible, and the differences will be emphasized when describing Embodiment 3. Obviously, if necessary, the contents not described in Embodiment 3 can be supplemented with the contents of Embodiments 1 and 2.

[0094] refer to Figure 7 The method for manufacturing a secondary battery according to Embodiment 3 of the present invention may also involve welding a plurality of electrode tabs 20 extending from one end of an electrode assembly formed by stacking electrodes and separators to an electrode lead 40 .

[0095] The electrode assembly 10 may be formed by alternately stacking electrodes and separators, and the electrode tab 20 may be a metal tab connected to each electrode and protruding from one side of the electrode. Therefore, the plurality of electrode tabs 20 may have a structure extending from one end of the electrode assembly 10. The stack in which the plurality of electrode tabs 20 are combined may be coupled to the electrode lead 40 to manufacture a secondary battery.

[0096] The method for manufacturing a secondary battery according to Embodiment 3 of the present invention may include a process of preparing a tape (a), a process of forming an electrode tab stack (b), a process of bonding with the tape (c), and a process of welding an electrode lead (d).

[0097] Alternatively, in Embodiment 3, a cutting process (c-1) may be further performed between processes (c) and (d).

[0098] Figure 7 The processes (a) and (b) may be the same as those previously described in Example 1.

[0099] The process (c) of bonding with tape may be a process of bonding the tape 31 to the electrode tab stack 30. This process may be a process of keeping the stack 30 of the assembled electrode tabs in a stable shape without moving or being disturbed. This process may be performed to gather the electrode tabs 20 for welding in a subsequent welding process of the electrode lead 40.

[0100] Figure 7 (c) shows the process. In addition, Figure 8 FIG. 2 shows a state where the tape 31 is attached to the electrode tab stack 30 in process (c). Figure 7 (c) and Figure 8 In the taping process (c), the tape 31 may be attached to each of both sides of the electrode tab stack 30 based on the width direction W of the electrode tab stack 30 .

[0101] In the method for manufacturing a secondary battery according to Embodiment 3 of the present invention, the tape 31 may be attached to the electrode tab stack 30 to provide the excess portion 31 - 1 protruding further outward in the width direction W from the side end of the electrode tab stack 30 .

[0102] exist Fig. 9 The cross-sectional view of FIG. 1 shows the principle of generating the excess portion 31-1. Fig. 9 In the figure to the left of the middle arrow, the tape 31 can be attached to surround the side of the electrode tab stack 30 so that there is a portion remaining further outward from the side end of the electrode tab based on the width direction W of the electrode tab stack 30. In addition, after the tape 31 is attached in this way, the upper tape and the lower tape are attached to each other by applying forces E1 and E2 vertically to the remaining outer portion. In this way, a structure such as Fig. 9 Here, the excess portion 31 - 1 may be provided such that a portion and another portion of the tape 31 disposed outside the side end of the electrode tab stack 30 in the width direction face each other.

[0103] In this way, the excess portion 31-1 of the tape 31 can be generated. When the formation of the excess portion 31-1 is completed in this way, the electrode assembly can have a Figure 8 Shape shown.

[0104] In order to gather the electrode tabs 20, the electrode tabs 20 may be attached in a tight state with tension applied, or may be attached with an appropriate strength without being too tight. Figure 8, the tape 31 may be attached to a horizontal portion of a portion where the electrode tabs 20 are gathered, and may also be partially attached to an inclined portion extending from the horizontal portion toward the electrode assembly.

[0105] In the process (c) of bonding with tape, the tape 31 may be attached to the top surface or the bottom surface of the electrode tab stack 30, but may not be attached to the portion to which the electrode lead 40 is to be welded. As described above, the welding area A to which the electrode lead 40 is welded may be formed in the portion to which the tape 31 is not attached (see Fig.11 ). Since the portion where the tape 31 is provided is a surface not suitable for welding, the tape 31 may not be attached to the surface to be welded. When attaching the tape 31, the tape attaching machine 120 may be used to adhere the cut tape 31 to the electrode tab stack 30.

[0106] Here, the tape attaching machine 120 may adhere the tape 31 to the electrode tab stack 30, and may be attached to the top surface, the side surface, and the bottom surface of the electrode tab stack 30. However, in Embodiment 3 of the present invention, the tape attaching machine 120 may adhere the tape 31 to the electrode tab stack 30, but provides an excess portion 31-1 that protrudes further outward from the side end of the electrode tab in the width direction.

[0107] In addition, a clamping device 150 may be provided which pulls the excess portions 31-1 provided on both sides of the electrode tab stack toward both sides based on the width direction W of the electrode tab stack 30. The clamping device 150 may be mainly used in a process of welding the electrode lead 40, which will be described below, but may also be used in the process (c) of bonding with an adhesive tape to tightly attach the adhesive tape 31.

[0108] The processes (b) and (c) may be performed separately, but may also be performed together. That is, if the process (b) of forming the electrode tab stack and the process (c) of bonding with a tape are performed simultaneously, the process is performed more efficiently and effectively.

[0109] refer to Figure 7 , in Embodiment 3 of the present invention, a cutting process (c-1) may be further performed between processes (c) and (d).

[0110] Specifically, the cutting process (c-1) may be a process of cutting one end of the bonded electrode tab stack 30 . Figure 7 (c-1) shows the process.

[0111] The cutting process (c-1) may be performed using a cutter 140 that cuts one end of the electrode tab stack 30 bonded by the tape attaching machine 120 into an appropriate length. In Embodiment 3 of the present invention, during the cutting process, the excess portion 31 - 1 of the tape may be cut together.

[0112] When the electrode tab stack 30 is cut into an appropriate length, the efficiency of the laser welding operation can be improved by cutting the electrode tab stack 30 into an appropriate length for subsequent laser welding. In addition, there is an effect of being able to adjust the length of the electrode tab stack 30 to fit the size of the final product of the secondary battery. Even at this time, in the method of fixing the electrode tab 20 with the tape 31 of the present invention, the electrode tab 20 can be fixed, so that the electrode tab 20 is easily cut.

[0113] Fig.10 A state in which one end of the electrode tab stack is cut by the cutter 140 is shown. Fig.10 The shape of the electrode tab stack 30 and the excess portion 31 - 1 of the tape is neatly cut along the cutting line L. Fig.10 In the embodiment, a central area of ​​the top surface of the electrode tab 20 to which the tape 31 is not attached may be a laser welding area A to which the electrode lead 40 is welded. Welding may be accurately performed on the welding area A after the cutting operation.

[0114] The process (d) of welding the electrode tab stack and the electrode lead may be a process of welding the electrode tab stack 30 and the electrode lead 40 which are overlapped and adhered with the tape using a welding machine. The process may be a process of joining the electrode tab stack 30 to the electrode lead 40 by welding. In addition, specifically, the process (d) of welding the electrode lead 40 may be a process of laser welding the electrode tab stack 30 and the electrode lead 40.

[0115] Figure 7 (d) shows the process. The process may be performed using a laser welding machine 130 , which is a device that irradiates welding laser to the electrode tab stack 30 and the electrode lead 40 .

[0116] In addition, in the third embodiment of the present invention, in the process (d) of welding the electrode lead 40, the clamping device 150 (see Figure 7 In a state where the excess portion 31-1 provided on both sides of the electrode tab stack 30 is clamped by F1 and F2), the electrode tab stack 30 and the electrode lead 40 can be welded to each other while the excess portion 31-1 is pulled to both sides based on the width direction W of the electrode tab stack 30.

[0117] In this case, the gap between the electrode tabs 20 can be eliminated. That is, the electrode tabs 20 can be in close contact with each other. When welding is performed while applying tension in this manner, the welding quality between the electrode tab stack 30 and the electrode lead 40 can be further improved.

[0118] When the method of gathering the electrode tabs 20 using the tape 31 according to Embodiment 3 of the present invention is used, the electrode tabs 20 may be gathered quickly and effectively to perform main welding of the electrode lead 40 and the electrode tabs 20 with significantly high efficiency.

[0119] [Example 4]

[0120] Fig.11 is a perspective view showing the internal configuration of a secondary battery according to Embodiment 4 of the present invention.

[0121] Embodiment 4 of the present invention is different from Embodiments 1 to 3 in that Embodiment 4 relates to a secondary battery manufactured by the method for manufacturing a secondary battery according to Embodiment 3.

[0122] The contents repeated with Embodiments 1 to 3 will be omitted as much as possible, and the differences will be emphasized when describing Embodiment 4. Obviously, if necessary, the contents not described in Embodiment 4 can be supplemented with the contents of Embodiments 1 to 3.

[0123] refer to Fig.11 , a secondary battery according to Embodiment 4 of the present invention may include an electrode assembly 10 , a pouch, an electrode tab stack 30 , an electrode lead 40 , and a tape 31 .

[0124] The electrode assembly 10 may be a stack provided by stacking electrodes and separators. A bag (not shown) may be configured to accommodate the electrode assembly 10 in an internal space. An electrode tab stack 30 may be provided by gathering a plurality of electrode tabs 20 extending from one end of the electrode assembly 10 and disposed inside the bag. The tape 31 may be configured to surround the electrode tab stack 30. Here, the tape 31 may be attached to each of the two sides of the electrode tab stack 30 based on the width direction W of the electrode tab stack 30.

[0125] The tape 31 may be attached to both sides of the electrode tab stack 300 , and the tape 31 may include a surplus portion 31 - 1 that further protrudes outward from the side ends of the electrode tab stack 300 in the width direction W.

[0126] The excess portion 31-1 may have a shape in which a portion of the tape 31 disposed outside the side end of the electrode tab stack 30 in the width direction W and another portion face each other. The tape 31 may be attached to the top and bottom surfaces of the electrode tab stack 30. In addition, the tape 31 may be attached to at least a portion of the side surface of the electrode tab stack 30 (see Fig. 9 ). When the tape 31 applies tension to the electrode tab stack 30, the electrode tabs 20 may be kept in close contact with each other.

[0127] In addition, in order to gather the electrode tabs 20, the electrode tabs 20 may be attached in a tight state with tension applied, or may be attached with an appropriate strength without being too tight. Based on the side view, the tape 31 may be attached to the horizontal portion of the portion where the electrode tabs 20 are gathered, and may also be partially attached to the inclined portion extending from the horizontal portion toward the electrode. That is, the thickness of the electrode tab stack 30 may be constant in the horizontal portion, but may become thicker in the inclined portion, and the tape 31 may be attached to a portion of the horizontal portion and the inclined portion.

[0128] In addition, the tape 31 may not be attached to the top and bottom surfaces of the electrode tab stack 30 to which the electrode lead 40 is to be welded. As described above, the welding region A to weld the electrode lead 40 may be formed in a portion to which the tape 31 is not attached (see Fig.11 ). Since the area to which the tape 31 is attached is a surface not suitable for welding, the tape 31 may not be attached to the surface to be welded.

[0129] The electrode lead 40 may have one side connected to the electrode tab stack 30 and the other side protruding to the outside of the bag (not shown). One side of the electrode lead 40 may be connected to the electrode tab stack 30 in the welding region A by laser welding.

[0130] Furthermore, according to the various effects of the present invention described in the above-described Embodiments 1 and 3, the secondary battery according to Embodiment 4 of the present invention as described above can be a secondary battery having excellent quality.

[0131] While embodiments of the present invention have been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.

[0132] [Explanation of Reference Numerals]

[0133] 10: Electrode assembly

[0134] 20: Electrode tabs

[0135] 30: Electrode tab stack

[0136] 31: Tape

[0137] 31-1: Excess

[0138] 40: Electrode lead

[0139] 41: Lead film

[0140] 110: Tab guide

[0141] 120: Tape attaching machine

[0142] 130: Laser welding machine

[0143] 140: Cutter

[0144] 150: Clamping device

[0145] L: Cutting line

Claims

1. A method for manufacturing a secondary battery, the method welding a plurality of electrode tabs to an electrode lead, the plurality of electrode tabs extending from one end of an electrode assembly formed by stacking electrodes and a separator, the method comprising: Process for preparing a tape having a desired size and shape (a); a process (b) of gathering the plurality of electrode tabs to form an electrode tab stack; A process (c) of bonding the electrode tab stack with the adhesive tape; as well as and welding the bonded electrode tab stack to the electrode lead (d). 2 . The method according to claim 1 , further comprising a cutting process ( c- 1 ) of cutting one end of the bonded electrode tab stack between the process (c) and the process (d).

3. The method according to claim 1, wherein: The process (a) of preparing the adhesive tape includes a process of cutting the adhesive tape into a desired size and shape to prepare the adhesive tape.

4. The method according to claim 1, wherein: In the process (b) of forming the electrode tab stack, the plurality of electrode tabs are pressed or guided from upper and lower sides of the electrode tabs to gather the electrode tabs, thereby forming the electrode tab stack.

5. The method according to claim 1, wherein: In the process (c) of bonding with the tape, the tape is attached to each of both sides of the electrode tab stack based on a width direction of the electrode tab stack.

6. The method according to claim 5, wherein: In the process (c) of bonding with the adhesive tape, the adhesive tape is attached to surround the top surface, the side surface, and the bottom surface of the electrode tab stack.

7. The method according to claim 6, wherein: In the process (c) of bonding with the tape, the tape is not attached to portions of the top and bottom surfaces of the electrode tab stack to which the electrode leads are to be welded.

8. The method according to claim 1, wherein: In the process (c) of bonding with the tape, the tape is attached to each of both sides of the electrode tab stack based on the width direction of the electrode tab stack, The tape is attached to the electrode tab stack to form a surplus portion that protrudes further outward from a side end of the electrode tab stack in a width direction.

9. The method according to claim 8, wherein: In the process (c) of bonding with the tape, the excess portion has a shape in which a portion and another portion of the tape disposed outside a side end of the electrode tab stack in a width direction face each other to be engaged with each other.

10. The method according to claim 1, wherein: Process (b) and process (c) are executed simultaneously.

11. The method according to claim 1, wherein: In the process (d) of welding the electrode lead, the electrode tab stack and the electrode lead are welded to each other by laser welding.

12. The method according to claim 11, wherein: In the process (d) of welding the electrode lead, the electrode tab stack and the electrode lead are welded to each other while the excess portion is pulled toward both sides based on the width direction of the electrode tab stack, while the excess portion is clamped on each of the two sides of the electrode tab stack using a clamping device.

13. An apparatus for manufacturing a secondary battery, the apparatus welding a plurality of electrode tabs to electrode leads, the plurality of electrode tabs extending from one end of an electrode assembly formed by stacking electrodes and separators, the apparatus comprising: a tape cutting unit configured to cut the tape into a desired size and shape; a tab guide configured to gather the plurality of electrode tabs to provide an electrode tab stack; a tape attaching machine configured to adhere the cut tape to the electrode tab stack; and A laser welding machine is configured to weld the bonded electrode tab stack to the electrode lead.

14. The device according to claim 13, wherein: The tape attaching machine is configured to adhere the tape to the electrode tab stack, The adhesive tape is attached to surround the top surface, the side surface and the bottom surface of the electrode tab stack.

15. The device according to claim 13, wherein: The tape attaching machine is configured to adhere the tape to the electrode tab stack, The adhesive tape is attached to the electrode tab stack to provide a surplus portion protruding outward from a side end of the electrode tab in a width direction. 16 . The apparatus according to claim 15 , further comprising a clamping device configured to pull the excess portions disposed on both sides of the electrode tab stack toward both sides based on a width direction of the electrode tab stack. 17 . The apparatus of claim 13 , further comprising a cutter configured to cut one end of the electrode tab stack adhered by the tape attaching machine.

18. A secondary battery comprising: an electrode assembly provided by stacking electrodes and separators; a bag configured to accommodate the electrode assembly in an inner space; an electrode tab stack provided by gathering a plurality of electrode tabs extending from one end of the electrode assembly and disposed inside the bag; an adhesive tape configured to surround the electrode tab stack; as well as An electrode lead has one side connected to the electrode tab stack and the other side protruding out of the bag.

19. The secondary battery according to claim 18, wherein The tape is attached to each of both sides of the electrode tab stack based on a width direction of the electrode tab stack.

20. The secondary battery according to claim 18, wherein The adhesive tape is attached to each of both sides of the electrode tab stack based on a width direction of the electrode tab stack, The adhesive tape includes an excess portion that protrudes further outward from a side end of the electrode tab stack in a width direction.

21. The secondary battery according to claim 20, wherein The excess portion has a shape in which a portion and another portion of the tape disposed outside a side end of the electrode tab stack in a width direction face each other to be engaged with each other.

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