Electrode tab welding apparatus, electrode tab welding method, and electrode assembly

Abstract

An electrode tab welding device according to an embodiment of the present invention can weld a plurality of electrode tabs of an electrode assembly. The electrode tab welding device may include a pair of tab guides for collecting the plurality of electrode tabs, a pair of alignment rollers for applying pressure to the plurality of electrode tabs collected by the pair of tab guides and rotating in a direction in which the outermost electrode tab is pressed toward the electrode assembly, and a welding section for welding the plurality of electrode tabs aligned by the pair of alignment rollers.

Description

[Technical field]

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2021-0186535 filed on December 23, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an electrode tab welding apparatus and an electrode tab welding method for welding a plurality of electrode tabs, and to an electrode assembly including a plurality of electrode tabs welded by the electrode tab welding apparatus or electrode tab welding method. [Background technology]

[0003] In general, a secondary battery means a battery that can be charged and discharged, unlike a primary battery that cannot be charged, and is widely used in electronic devices such as mobile phones, laptops, and camcorders, electric vehicles, etc. In particular, lithium secondary batteries have a larger capacity and higher energy density than nickel-cadmium batteries or nickel-metal hydride batteries, and therefore their use is rapidly increasing.

[0004] Depending on the shape of the battery case, secondary batteries can be classified into cylindrical batteries and prismatic batteries in which the electrode assembly is housed in a cylindrical or prismatic metal can, and pouch-type batteries in which the electrode assembly is housed in a pouch-shaped case made of an aluminum laminate sheet.

[0005] FIG. 1 is a diagram showing an example of a pouch-type secondary battery. The pouch-type secondary battery 1 includes an electrode assembly 10 formed by alternately stacking electrodes and separators, and a pouch 20 in which the electrode assembly 10 is housed. An electrode tab 15 may be connected to an electrode of the electrode assembly 10. The electrode tabs 15 may be connected to an electrode lead 17 after being welded to each other in a predetermined area. The pouch 20 includes a concave cup portion 21 for housing the electrode assembly 10. The pouch 20 may have one or two cup portions 21. FIG. 1 illustrates a pouch 20 including a left cup portion and a right cup portion. A peripheral portion (terrace) 23 for sealing is formed on the periphery of the cup portion 21.

[0006] However, when a pulling force is applied to the electrode tab 15 due to the deformation of the peripheral portion 23 of the pouch 20, the electrode tab 15 may be gradually pulled and broken. Or, when a pulling force is applied to the electrode tab 15 due to the expansion of the pouch 20, the electrode tab 15 may be gradually pulled and broken. Such breaking is considered to be the main cause of fires. In recent years, in the case of pouch-type secondary batteries, the length of the peripheral portion 23 has been reduced to increase the energy density in response to demands for higher capacity and performance, but this leads to a reduction in the "length from the electrode assembly 10 to the welding point of the electrode tab 15" of the electrode tab 15, further increasing the risk of breaking. Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide an electrode tab welding apparatus and an electrode tab welding method that prevent breakage of the electrode tab. Another object of the present invention is to provide an electrode assembly in which breakage of an electrode tab is prevented. [Means for solving the problem]

[0008] An electrode tab welding device according to an embodiment of the present invention can weld a plurality of electrode tabs of an electrode assembly. The electrode tab welding device may include a pair of tab guides for collecting the plurality of electrode tabs, a pair of alignment rollers for applying pressure to the plurality of electrode tabs collected by the pair of tab guides and rotating in a direction in which the outermost electrode tab is pressed toward the electrode assembly, and a welding section for welding the plurality of electrode tabs aligned by the pair of alignment rollers.

[0009] A point on the electrode assembly where the pair of alignment rollers press the electrode tabs may be farther away than a point on the electrode assembly where the pair of tab guides press the electrode tabs.

[0010] The pair of alignment rollers can rotate while pressing the electrode tabs when the pair of tab guides form a first gap, and can move away from the electrode tabs when the pair of tab guides form a second gap smaller than the first gap.

[0011] The weld portion can weld the electrode tabs together when the pair of tab guides form the second spacing. The pair of alignment rollers may include an elastomeric material.

[0012] The pair of alignment rollers may be disposed to face each other in a height direction of the electrode assembly with the electrode tabs therebetween, and a distance between the pair of alignment rollers may be configured to be adjustable.

[0013] An electrode tab welding method according to an embodiment of the present invention can weld a plurality of electrode tabs of an electrode assembly. The electrode tab welding method may include the steps of: moving a pair of tab guides close to each other to gather the plurality of electrode tabs; rotating a pair of alignment rollers while applying pressure to the plurality of electrode tabs gathered by the pair of tab guides to push an outermost electrode tab among the plurality of electrode tabs toward the electrode assembly; and welding the plurality of electrode tabs aligned by the pair of alignment rollers to each other at a welded portion.

[0014] When the pair of alignment rollers rotate, the pair of tab guides can have a first spacing, and when the welding portion welds the plurality of electrode tabs, the pair of tab guides can have a second spacing that is narrower than the first spacing.

[0015] As the pair of alignment rollers rotate, a step can be generated between outer ends of the plurality of electrode tabs. The pair of alignment rollers may be spaced apart from the electrode tabs as the welds weld the electrode tabs together.

[0016] An electrode assembly according to an embodiment of the present invention may include a plurality of electrodes stacked with separators interposed therebetween, and a plurality of electrode tabs connected to the plurality of electrodes and welded to each other to form a welded portion. Both outermost electrode tabs of the plurality of electrode tabs may be bent outwardly in a convex shape. The outermost electrode tab may include a first section extending from the electrode, and a second section extending from the first section and having a steeper slope than the first section. The first section may include a flat portion connected to the electrode and formed flat, and a bent portion connecting the flat portion and the second section and formed by bending.

[0017] The electrode tabs located on the outer side may bend more greatly. The outer end of the outermost electrode tab may have an inward step with respect to the outer ends of the other electrode tabs. The outermost electrode tab may further include a third section extending from the second section to the welded portion and having a gentler slope than the second section. Effect of the Invention

[0018] According to a preferred embodiment of the present invention, the electrode tabs are welded by the welding portion while the electrode tabs are pressed toward the electrode assembly by the alignment roller, so that the length from the electrode to the welded portion can be increased for each electrode tab, particularly the outermost electrode tab, which can prevent the electrode tabs, particularly the outermost electrode tab, from being broken or disconnected due to external forces such as deformation, e.g., bending, of the electrode lead, thereby improving the safety and reliability of the electrode assembly. In addition, the present invention can include effects that can be easily predicted by a person skilled in the art from the configurations according to the preferred embodiments of the present invention. [Brief description of the drawings]

[0019] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical ideas of the present invention. Therefore, the present invention should not be interpreted as being limited to only the matters depicted in the drawings.

[0020] [Figure 1] FIG. 1 is a diagram showing an example of a pouch-type secondary battery. [Figure 2a] 1A to 1C are diagrams for explaining an example of a process that can be applied when welding electrode tabs of a pouch-type secondary battery. [Figure 2b] 1A to 1C are diagrams for explaining an example of a process that can be applied when welding electrode tabs of a pouch-type secondary battery. [Figure 2c] 1A to 1C are diagrams for explaining an example of a process that can be applied when welding electrode tabs of a pouch-type secondary battery. [Figure 2d] 1A to 1C are diagrams for explaining an example of a process that can be applied when welding electrode tabs of a pouch-type secondary battery. [Diagram 3] 1 is a cross-sectional view showing a portion of a battery module in which a plurality of pouch-type batteries are housed in a case. [Figure 4] 1A to 1C are diagrams for explaining the configuration and operation of an electrode tab welding device according to an embodiment of the present invention. [Diagram 5]1A to 1C are diagrams for explaining the configuration and operation of an electrode tab welding device according to an embodiment of the present invention. [Figure 6] 1A to 1C are diagrams for explaining the configuration and operation of an electrode tab welding device according to an embodiment of the present invention. [Figure 7] 5 is a flow chart of an electrode tab welding method according to another embodiment of the present invention. [Figure 8] 13A and 13B are diagrams illustrating an electrode assembly according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in order to enable those skilled in the art to easily carry out the present invention. However, the present invention may be realized in various different forms, and is not limited to the following embodiments.

[0022] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the description or related prior art that may unnecessarily obscure the gist of the present invention will be omitted. In this specification, when referring to components in each drawing, the same or similar reference symbols will be used throughout the specification to refer to the same or similar components.

[0023] Furthermore, the terms and words used in this specification and the claims should not be interpreted in a limited manner to their ordinary or dictionary meanings, but should be interpreted in a manner that is consistent with the technical ideas of the present invention, based on the principle that inventors can appropriately define the concepts of terms in order to best describe their invention.

[0024] 2a to 2d are diagrams illustrating an example of a process that can be applied when welding electrode tabs of a pouch-type secondary battery, and FIG. 3 is a cross-sectional view showing a portion of a battery module in which multiple pouch-type batteries are housed in a case.

[0025] First, as shown in Fig. 2a, an electrode assembly 10 may be prepared in which a plurality of electrodes 11 and a plurality of separators 13 are alternately stacked. The plurality of electrodes 11 may include a positive electrode and a negative electrode, and each electrode 11 may be connected to an electrode tab 15. For convenience of explanation, only a negative electrode tab connected to a negative electrode is shown in the drawings, but a person skilled in the art will easily understand that a positive electrode tab connected to a positive electrode may also be provided in the electrode assembly 10 and may be welded in the same manner as the negative electrode tab.

[0026] 2b, a pair of tab guides 30 may press the electrode tabs 15 to gather the electrode tabs 15. The pair of tab guides 30 may face each other in the height direction of the electrode assembly 10 with the electrode tabs 15 therebetween, and the distance between them may be adjustable.

[0027] 2c, the electrode tabs 15 may be welded via a welding portion 50. More specifically, the welding portion 50 may form a welded portion 16 by welding the electrode tabs 15 together. With respect to the electrode assembly 10, the welded portion 16 formed on the electrode tabs 15 may be farther away from a point where the electrode tabs 15 are pressed by a pair of tab guides 30.

[0028] Through this process, an electrode assembly 10 can be manufactured having a plurality of electrode tabs 15 welded to each other at a welded portion 16. After connecting electrode leads 17 (see FIG. 1) to the plurality of electrode tabs 15 welded to each other, the electrode assembly 10 can be housed in a pouch 20 (see FIG. 1) to manufacture a pouch-type battery 1.

[0029] As shown in FIG. 3, a plurality of pouch-type batteries 1 can be housed in a case C to be manufactured into a battery module. However, during the manufacture of the battery module, the periphery 23 of the pouch 20 can bend. The deformation of the periphery 23 can induce bending of the electrode lead 17, which can result in a pulling force on the electrode tab 15 connected to the electrode lead 17. This force can pull the electrode tab 15 too hard, causing breakage of the electrode tab 15, and can be particularly severe on the outermost electrode tab 15a. The expansion of the pouch-type battery 1 can also cause the above-mentioned breakage problem.

[0030] The present invention, which will be described in detail below, is intended to solve the above-mentioned problem of disconnection. 4 to 6 are diagrams for explaining the configuration and operation of an electrode tab welding device according to one embodiment of the present invention.

[0031] An electrode tab welding device according to an embodiment of the present invention can weld a plurality of electrode tabs 15 of an electrode assembly 10. More specifically, the electrode tab welding device may include a pair of tab guides 30 that collect the plurality of electrode tabs 15, a pair of alignment rollers 40 that apply pressure to the plurality of electrode tabs 15 collected by the pair of tab guides 30 and rotate in a direction in which the electrode tabs 15 are pressed toward the electrode assembly 10, and a welding unit 50 that welds the plurality of electrode tabs 15 aligned by the pair of alignment rollers 40.

[0032] The pair of tab guides 30 may face each other with the electrode tabs 15 interposed therebetween in the height direction of the electrode assembly 10. The pair of tab guides 30 may be configured so that the distance between them is adjustable. More specifically, at least one of the pair of tab guides 30 may be configured to be movable up and down in the height direction of the electrode assembly 10.

[0033] 4, the pair of tab guides 30 can approach each other to gather the multiple electrode tabs 15. In the process, the pair of tab guides 30 can contact a pair of outermost electrode tabs 15a of the multiple electrode tabs 15. The narrower the distance between the pair of tab guides 30 , the stronger the pressure that the pair of tab guides 30 can apply to the multiple electrode tabs 15 .

[0034] The pair of alignment rollers 40 may face each other with the electrode tabs 15 interposed therebetween in the height direction of the electrode assembly 10. The pair of alignment rollers 40 may be configured such that the distance between them is adjustable. More specifically, at least one of the pair of alignment rollers 40 may be configured to be movable up and down in the height direction of the electrode assembly 10.

[0035] 4, the pair of alignment rollers 40 can rotate while applying pressure to the multiple electrode tabs 15 collected by the pair of tab guides 30. More specifically, the pair of alignment rollers 40 can contact the pair of outermost electrode tabs 15a and can rotate in a direction that presses the pair of outermost electrode tabs 15a toward the electrode assembly 10.

[0036] The electrode tabs 15 may be pushed toward the electrode assembly 10 due to frictional forces between each other, and the electrode tabs 15 located closer to the outside may be pushed more toward the electrode assembly 10. This may cause a step s (see FIG. 8 ) to be generated between the outer ends of the electrode tabs 15. That is, the pair of alignment rollers 40 may align the electrode tabs 15 such that a step is generated between the outer ends of the electrode tabs 15.

[0037] The alignment roller 40 may be made of an elastic material having a high surface friction coefficient. More specifically, the alignment roller 40 may include an elastomer material such as rubber. As a result, the frictional force between the alignment roller 40 and the outermost electrode tab 15a is maintained high, so that the alignment roller 40 can rotate without slipping on the outermost electrode tab 15a. In addition, the alignment roller 40 can be elastically deformed by pressing the outermost electrode tab 15a, so that damage to the outermost electrode tab 15a can be prevented.

[0038] With respect to the electrode assembly 10, the pair of alignment rollers 40 may be located farther away from the pair of tab guides 30. More specifically, with respect to the electrode assembly 10, a point where the pair of alignment rollers 40 presses the multiple electrode tabs 15 may be farther away from a point where the pair of tab guides 30 presses the multiple electrode tabs 15.

[0039] As shown in FIG. 5, after the electrode tabs 15 are aligned, a pair of tab guides 30 can apply more pressure to the electrode tabs 15 to fix them in place.

[0040] More specifically, the pair of alignment rollers 40 can rotate while pressing the multiple electrode tabs 15 when the pair of tab guides 30 form a first gap g1, and can move away from the multiple electrode tabs 15 when the pair of tab guides 30 form a second gap g2 that is smaller than the first gap g1.

[0041] The pair of alignment rollers 40 can align the multiple electrode tabs 15 when the pair of tab guides 30 form a first gap g1, and when the alignment of the multiple electrode tabs 15 is completed, the pair of tab guides 30 can move closer to each other to form a second gap g2 that is smaller than the first gap g1.

[0042] When the pair of tab guides 30 form the first gap g1, the electrode tabs 15 are not completely fixed between the pair of tab guides 30 and are movable in the longitudinal direction. Therefore, when the pair of alignment rollers 40 rotate, the electrode tabs 15 can be pressed inward between the pair of tab guides 30.

[0043] When the pair of tab guides 30 form the second gap g2, the plurality of electrode tabs 15 can be fixed between the pair of tab guides 30. In this way, the plurality of electrode tabs 15 can be fixed between the pair of tab guides 30 in an aligned state.

[0044] Once the electrode tabs 15 are secured between the pair of tab guides 30 , the pair of alignment rollers 40 can be moved away from each other to space them from the electrode tabs 15 .

[0045] 6, the welding portion 50 may be formed by welding a plurality of electrode tabs 15 aligned by a pair of alignment rollers 40 to form a welded portion 16. The welded portion 16 may be a portion where a plurality of electrode tabs 15 are welded to each other.

[0046] The welding portion 50 can perform welding in a state in which the electrode tabs 15 are fixed by the pair of tab guides 30. More specifically, the welding portion 50 can weld the electrode tabs 15 when the pair of tab guides 30 form the second gap g2.

[0047] For example, the welding unit 50 may ultrasonically weld the electrode tabs 15 together. In this case, the welding unit 50 may include an anvil located on one side (e.g., below) of the electrode tabs 15 and a horn located on the other side (e.g., above) of the electrode tabs 15. The welding unit 50 may be configured such that the distance between the anvil and the horn is adjustable. With the electrode tabs 15 pressed between the anvil and the horn, the horn may vibrate at a high frequency, thereby welding the electrode tabs 15 together.

[0048] With respect to the electrode assembly 10, the welding portion 50 may be located farther away from the pair of tab guides 30. More specifically, with respect to the electrode assembly 10, the welded portion 16 may be located farther away from a point where the pair of tab guides 30 press the multiple electrode tabs 15.

[0049] The operation of the welding device according to this embodiment will be described below. 4, the pair of tab guides 30 may approach each other and press the outermost electrode tabs 15a to gather the electrode tabs 15. At this time, the pair of tab guides 30 may apply a relatively weak pressure so that the electrode tabs 15 are not completely fixed.

[0050] Thereafter, the pair of alignment rollers 40 may approach each other to press the outermost electrode tab 15a, and may rotate to push the outermost electrode tab 15a toward the electrode assembly 10. As a result, the electrode tabs 15 may be pushed toward the electrode assembly 10 and aligned between the pair of tab guides 30. Since the electrode tabs 15 located closer to the outside are pushed more, the electrode tabs 15 may have steps at their outer ends.

[0051] Thereafter, as shown in FIG. 5, the pair of tab guides 30 can be moved closer together to fully secure the multiple electrode tabs 15, and the pair of alignment rollers 40 can be moved away from each other, away from the outermost electrode tabs 15a.

[0052] Thereafter, as shown in FIG. 6, a weld 50 may be formed by welding the plurality of electrode tabs 15 together to form a welded portion 16 . Since the welding part 50 welds the electrode tabs 15 while the tab guide 30 fixes the aligned electrode tabs 15, the length L (see FIG. 8) from the electrode assembly 10 to the welded part 16 can be made longer for the electrode tabs 15, particularly the outermost electrode tab 15a. In other words, the electrode tabs 15, particularly the outermost electrode tab 15a, can have a length margin.

[0053] This makes it possible to prevent the electrode tabs 15, particularly the outermost electrode tab 15a, from being broken or disconnected due to expansion of the electrode assembly 10 or an external force applied to the electrode tabs 15, etc.

[0054] FIG. 7 is a flow chart of an electrode tab welding method according to another embodiment of the present invention. Hereinafter, an electrode tab welding method using the above-described electrode tab welding apparatus will be described as another embodiment of the present invention.

[0055] The electrode tab welding method according to the present embodiment can weld a plurality of electrode tabs 15 of an electrode assembly 10. The electrode tab welding method can include a step (S10) of a pair of tab guides 30 approaching each other to gather the plurality of electrode tabs 15, a step (S20) of a pair of alignment rollers 40 rotating while applying pressure to the plurality of electrode tabs 15 gathered by the pair of tab guides 30 to press the outermost electrode tab 15a toward the electrode assembly 10, and a step (S30) of a welding portion 50 welding the plurality of electrode tabs 15 aligned by the pair of alignment rollers 40 to each other.

[0056] During the step (S10) of gathering the electrode tabs 15, the pair of tab guides 30 can gather the electrode tabs 15 by pushing the outermost electrode tabs 15a toward each other.

[0057] During the step (S20) of pushing the outermost electrode tab 15a toward the electrode assembly 10, the pair of alignment rollers 40 can approach each other to push the outermost electrode tab 15a, and can rotate so that the outermost electrode tab 15a is pushed toward the electrode assembly 10.

[0058] When the pair of alignment rollers 40 rotate, the pair of tab guides 30 can be spaced apart by a first distance g1. The pair of tab guides 30 spaced apart by the first distance g1 can apply a relatively weak pressure to the electrode tabs 15 so that they are not completely fixed.

[0059] As a result, the electrode tabs 15 may be pushed toward the electrode assembly 10 and aligned between the pair of tab guides 30 due to the mutual frictional force. Since the electrode tabs 15 located on the outer side are pushed more, the electrode tabs 15 may have steps at their outer ends.

[0060] During the step (S30) of welding the electrode tabs 15 to each other, the welding portion 50 may form the welded portion 16 by welding the electrode tabs 15 to each other. When the welding portion 50 welds the electrode tabs 15, the pair of tab guides 30 can form a second gap g2 narrower than the first gap g1. The pair of tab guides 30 forming the second gap g2 can completely fix the electrode tabs 15. This allows the electrode tabs 15 to be welded by the welding portion 50 while maintaining their alignment.

[0061] In addition, when the welding portion 50 welds the electrode tabs 15, the pair of alignment rollers 40 may be spaced apart from the electrode tabs 15. For example, the electrode assembly 10 may be moved from a first process position where the alignment rollers 40 are located to a second process position where the welding portion 50 is located. In this way, the welding portion 15 may weld the electrode tabs 15 regardless of the position of the alignment rollers 40.

[0062] FIG. 8 is a diagram showing an electrode assembly according to still another embodiment of the present invention. Hereinafter, an electrode assembly 10 including a plurality of electrode tabs 15 welded by the above-mentioned electrode tab welding apparatus or electrode tab welding method will be described as another embodiment of the present invention.

[0063] The electrode assembly 10 according to the present embodiment may include a plurality of electrodes 11 stacked with a plurality of separators 13 interposed therebetween, and a plurality of electrode tabs 15 connected to the plurality of electrodes 11 and welded to each other to form welded parts 16. In addition, both outermost electrode tabs 15a of the plurality of electrode tabs 15 may be bent in an outwardly convex shape.

[0064] At least some of the electrode tabs 15 may be bent in an outwardly convex shape, and the electrode tabs 15 located closer to the outside may be bent more greatly. Thus, the outermost electrode tab 15a may be bent the most greatly.

[0065] The length L from the electrode 11 to the welded portion 16 for the outermost electrode tab 15a can be longer than when the outermost electrode tab 15a is formed by being pulled without being bent. This makes it possible to prevent the outermost electrode tab 15a from being broken or disconnected due to the expansion of the electrode assembly 10 or an external force applied to the electrode tab 15.

[0066] More specifically, the outermost electrode tab 15a may include a first section 151 extending from the electrode 11, and a second section 152 extending from the first section 151 and having a steeper slope than the first section 151. The outermost electrode tab 15a may further include a third section 153 extending from the second section 152 to the welded portion 16 and having a gentler slope than the second section 152. Such a configuration of the outermost electrode tab 15a is a feature obtained by welding the outermost electrode tab 15a in an aligned state by being pressed toward the electrode assembly 10 by the alignment roller 40.

[0067] The first section 151 may include a flat portion 151a connected to the electrode 11 and formed flat, and a bent portion 151b connecting the flat portion 151a and the second section 152. That is, the point where the outermost electrode tab 15a starts to bend may be spaced a predetermined distance from the electrode 11 with the flat portion 151a therebetween. This has the advantage of preventing excessive stress concentration from occurring on the outermost electrode tab 15a.

[0068] The outer end of the outermost electrode tab 15a may have a step on the inside relative to the outer ends of the other electrode tabs 15. For example, a predetermined step S may be formed between the outer end of the outermost electrode tab 15 and the outer end of the central electrode tab.

[0069] However, cutting or the like may be performed to make the outer ends of the multiple electrode tabs 15 coincide with each other. In this case, it is not necessary to form a step between the outer end of the outermost electrode tab 15a and the outer ends of the other electrode tabs 15a.

[0070] The above description is merely an illustrative example of the technical concept of the present invention, and various modifications and variations are possible within the scope of the essential characteristics of the present invention, if one has ordinary knowledge in the technical field to which the present invention pertains.

[0071] Therefore, the embodiments disclosed in the present invention are intended to explain and not to limit the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by such embodiments.

[0072] The scope of protection of the present invention should be interpreted according to the claims set forth below, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention. [Explanation of symbols]

[0073] 10: Electrode assembly 11: Electrode 13: Separator 15: Electrode tab 15a: Outermost electrode tab 151: First Section 151a: Flat section 151b: Bent section 152: Second Section 153: Third Section 16: Welded part 30: Tab Guide 40: Alignment roller 50: Welded parts

Claims

1. An electrode tab welding device for welding a plurality of electrode tabs of an electrode assembly, comprising: a pair of tab guides for collecting the plurality of electrode tabs; a pair of alignment rollers which press the electrode tabs gathered by the pair of tab guides and rotate in a direction in which the outermost electrode tabs are pushed toward the electrode assembly; a welding section that welds the electrode tabs aligned by the pair of alignment rollers; 1. An electrode tab welding apparatus comprising:

2. 2. The electrode tab welding apparatus of claim 1, wherein a point at which the pair of alignment rollers press the electrode tabs is farther from a point at which the pair of tab guides press the electrode tabs with respect to the electrode assembly.

3. The pair of alignment rollers include the pair of tab guides rotate while applying pressure to the electrode tabs when the pair of tab guides form a first gap; The electrode tab welding apparatus of claim 1 , wherein the pair of tab guides are spaced apart from the plurality of electrode tabs at a second spacing that is smaller than the first spacing.

4. The welded portion is 4. The electrode tab welding apparatus of claim 3, wherein said pair of tab guides welds said plurality of electrode tabs when said pair of tab guides are at said second spacing.

5. The electrode tab welding apparatus of claim 1 , wherein the pair of alignment rollers comprises an elastomeric material.

6. The pair of alignment rollers include 2. The electrode tab welding device according to claim 1, wherein the electrode tabs are disposed opposite each other in the height direction of the electrode assembly, and the distance between the electrode tabs is adjustable.

7. 1. An electrode tab welding method for welding a plurality of electrode tabs of an electrode assembly, comprising: a pair of tab guides moving toward each other to gather the plurality of electrode tabs; a pair of alignment rollers rotating while applying pressure to the electrode tabs collected by the pair of tab guides to push an outermost electrode tab of the electrode tabs toward the electrode assembly; welding the electrode tabs together such that the welds are aligned by the pair of alignment rollers; 13. An electrode tab welding method comprising:

8. When the pair of alignment rollers rotate, the pair of tab guides form a first spacing; The electrode tab welding method according to claim 7 , wherein the pair of tab guides form a second spacing narrower than the first spacing when the welded portion welds the plurality of electrode tabs.

9. The electrode tab welding method of claim 7 , wherein the pair of alignment rollers generates a step between outer ends of the plurality of electrode tabs as the pair of alignment rollers rotate.

10. The electrode tab welding method of claim 7 , wherein the pair of alignment rollers are spaced apart from the plurality of electrode tabs as the weld welds the plurality of electrode tabs.

11. A plurality of electrodes stacked with separators interposed therebetween; a plurality of electrode tabs connected to the plurality of electrodes and welded to each other to form a welded portion; Including, both outermost electrode tabs of the plurality of electrode tabs are bent outwardly and convexly; The outermost electrode tab is a first section extending from the electrode; a second section extending from the first section and having a steeper slope than the first section; The first section is a flat portion connected to the electrode and formed flat; a bent portion connecting the flat portion and the second section, the bent portion being bent.

12. The electrode assembly of claim 11 , wherein the electrode tabs bend more toward the outside than toward the inside.

13. The electrode assembly of claim 11 , wherein an outer end of the outermost electrode tab has an inward step with respect to outer ends of the other electrode tabs.

14. The outermost electrode tab is The electrode assembly of claim 11 , further comprising a third section extending from the second section to the welded portion and having a more gentle slope than the second section.

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