Electrode assembly, secondary battery including electrode assembly, and method for manufacturing electrode assembly

Abstract

The present invention relates to an electrode assembly, a secondary battery including an electrode assembly, and a method for manufacturing an electrode assembly. The electrode assembly according to the present invention includes an electrode stack in which a plurality of electrodes and separators are alternately stacked, and electrode leads electrically connected to the electrode stack. The electrodes include electrode current collectors including electrode tabs extending to their ends. The electrode current collectors include a polymer layer and metal layers stacked on both sides of the polymer layer in the stacking direction. The electrode tabs of the electrode current collectors, each provided on a plurality of electrodes, form a stack of tabs that are brought together, and further include metal clips that enclose the ends of the stack of tabs. The electrode leads are electrically connected to the electrode stack by being connected to one side of the metal clips.

Description

[[Technical Field]]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0107661 filed on August 17, 2023, and all contents disclosed in the documents of the corresponding Korean patent application are incorporated herein by reference as part of the present specification.

[0002] The present invention relates to an electrode assembly, a secondary battery including the electrode assembly, and a method for manufacturing an electrode assembly. [[Background Art]]

[0003] Unlike primary batteries, secondary batteries can be recharged, and have been extensively researched and developed in recent years due to the possibility of miniaturization and increased capacity. With technological development and increasing demand for applications such as electric vehicles, energy storage systems (ESS), and mobile devices, the demand for secondary batteries as energy sources has increased sharply. However, the safety performance of secondary batteries cannot keep pace with the development speed of related technologies. To solve this problem, there is a method of improving safety by forming an electrical short to drain energy or short-circuiting the electrical connection before abnormal behavior of the secondary battery occurs.

[0004] Secondary batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries according to the shape of the battery case. In a secondary battery, the electrode assembly installed inside the battery case is a chargeable and dischargeable power generation element composed of a stacked structure of electrodes and separators.

[0005] Electrode assemblies are generally classified into the following types: a Jelly-roll type obtained by interposing a separator between sheet-shaped positive and negative electrodes each having an active material coated on a current collector and winding the resulting structure; a stacked type obtained by sequentially stacking a plurality of positive and negative electrodes with separators interposed between each adjacent electrode; and a stack / folding type obtained by winding stacked unit cells with a long separation film. [[Summary of the Invention]] [Problems that the invention aims to solve]

[0006] One aspect of the present invention is to provide an electrode assembly with improved weldability, a secondary battery including the electrode assembly, and a method for manufacturing the electrode assembly. [Means for solving the problem]

[0007] An electrode assembly according to an embodiment of the present invention includes an electrode laminate in which a plurality of electrodes and separators are alternately stacked, and an electrode lead electrically connected to the electrode laminate, wherein the electrode includes an electrode current collector including an electrode tab extending to its end, the electrode current collector includes a polymer layer and metal layers stacked on both sides of the polymer layer in the stacking direction, the electrode tabs of the electrode current collector provided on each of the plurality of electrodes form a tab laminate by being gathered together, and further includes a metal clip that encloses the end of the tab laminate, and the electrode lead can be electrically connected to the electrode laminate by being connected to one side of the metal clip.

[0008] Furthermore, a secondary battery according to an embodiment of the present invention includes an electrode assembly and a battery case housing the electrode assembly, the electrode assembly includes an electrode stack in which a plurality of electrodes and separators are alternately stacked, and electrode leads electrically connected to the electrode stack, the electrode includes an electrode current collector including an electrode tab extending to its end, the electrode current collector includes a polymer layer and metal layers stacked on both sides of the polymer layer in the stacking direction, the electrode tabs of the electrode current collector provided on each of the plurality of electrodes form a tab stack by being gathered together, and further includes a metal clip that encloses the end of the tab stack, the electrode leads can be electrically connected to the electrode stack by being connected to one side of the metal clip.

[0009] Furthermore, the method for manufacturing an electrode assembly according to an embodiment of the present invention includes a lamination process of forming a current collector laminate by laminating metal layers on both sides of a polymer layer, and a tab formation process of forming electrode tabs by notching (notching) the end portion of the laminate, and may include a current collector formation step of forming an electrode current collector, an electrode laminate formation step of forming an electrode laminate by alternately laminating a large number of electrodes and separators including the electrode current collector, a tab assembly step of forming a tab laminate by bringing together the electrode tabs of the electrode current collectors provided on each of the large number of electrodes, a lead connection step of connecting electrode leads to one side of a metal sheet, and a folding step of forming a metal clip by folding the end of the tab laminate so that the other side of the metal sheet wraps around it. [Effects of the Invention]

[0010] According to the present invention, an electrode current collector in which metal layers are laminated on both sides of a polymer layer has electrode tabs that are gathered together, and a metal clip wraps around the end of the tab laminate, and an electrode lead is connected to the metal clip, thereby significantly improving the weldability of the electrode tabs and electrode lead. [Brief explanation of the drawing]

[0011] [Figure 1] This is a cross-sectional view showing an electrode assembly according to an embodiment of the present invention. [Figure 2] This is a cross-sectional view showing the main part of an electrode assembly according to an embodiment of the present invention. [Figure 3] This is a perspective view showing the electrode current collector in an electrode assembly according to an embodiment of the present invention. [Figure 4] This is a cross-sectional view showing an electrode stack in an electrode assembly according to an embodiment of the present invention. [Figure 5] This is a cross-sectional view showing a first example of an electrode current collector in an electrode assembly according to an embodiment of the present invention. [Figure 6] This is a cross-sectional view showing a second example of an electrode current collector according to an embodiment of the present invention. [Figure 7]This is a cross-sectional view showing a third example of an electrode current collector according to an embodiment of the present invention. [Figure 8] This is a cross-sectional view showing a secondary battery including an electrode assembly according to an embodiment of the present invention. [Figure 9] This is a perspective view showing the lamination process in a method for manufacturing an electrode assembly according to an embodiment of the present invention. [Figure 10] This is a perspective view showing the tab formation process in a method for manufacturing an electrode assembly according to an embodiment of the present invention. [Figure 11] This is a cross-sectional view showing the tab assembly step in a method for manufacturing an electrode assembly according to an embodiment of the present invention. [Figure 12] This is a cross-sectional view showing the lead connection step in a method for manufacturing an electrode assembly according to an embodiment of the present invention. [Figure 13] This is a cross-sectional view showing the placement step in a method for manufacturing an electrode assembly according to an embodiment of the present invention. [Figure 14] This is a cross-sectional view showing the folding step in a method for manufacturing an electrode assembly according to an embodiment of the present invention. [Figure 15] This is a cross-sectional view showing an example of a stamping step in a method for manufacturing an electrode assembly according to an embodiment of the present invention. [Figure 16] This is a cross-sectional view showing another example of the stamping step in a method for manufacturing an electrode assembly according to an embodiment of the present invention. [Modes for carrying out the invention]

[0012] The object, particular advantages, and novel features of the present invention will become more apparent from the following detailed description relating to the accompanying drawings and from preferred embodiments. It should be noted that, in assigning reference numerals to components in each drawing in this specification, efforts have been made to ensure that the same component has the same number whenever possible, even if it appears in different drawings. Furthermore, the present invention can be realized in a variety of different forms and is not limited to the embodiments described herein. In describing the present invention, detailed descriptions of related prior art that could obscure the essence of the invention are omitted.

[0013] Electrode assembly according to an embodiment FIG. 1 is a cross-sectional view showing an electrode assembly according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing main parts of the electrode assembly according to an embodiment of the present invention, and FIG. 3 is a perspective view showing an electrode current collector in the electrode assembly according to an embodiment of the present invention.

[0014] Referring to FIGS. 1 to 3, an electrode assembly 10 according to an embodiment of the present invention includes an electrode stack 100 in which a plurality of electrodes 130 and separators 140 are alternately stacked, and an electrode lead 200 electrically connected to the electrode stack 100; the electrode 130 includes an electrode current collector 110 including an electrode tab 111 extending to an end portion, the electrode current collector 110 includes, in a stacking direction D, a polymer layer 112 and metal layers 115 respectively stacked on both surfaces of the polymer layer 112; the electrode tabs 111 of the electrode current collectors 110 respectively provided on the plurality of electrodes 130 form a tab stack T gathered together, and the electrode assembly further includes a metal clip 300 wrapping an end portion of the tab stack T, and the electrode lead 200 is electrically connected to the electrode stack 100 by being connected to one side portion of the metal clip 300.

[0015] FIG. 4 is a cross-sectional view showing an electrode stack in an electrode assembly according to an embodiment of the present invention.

[0016] More specifically, referring to FIG. 1 and FIG. 4, the electrode stack 100 is a chargeable / dischargeable power generating element, in which a plurality of electrodes 130 and separators 140 are alternately stacked.

[0017] The electrode 130 includes an electrode current collector 110 including an electrode tab 111 extending to an end portion.

[0018] Here, the electrode 130 may include an electrode current collector 110 and an electrode active material 120 coated on one or both sides of the electrode current collector 110. Here, the electrode 130 may have a surfaced region where the electrode active material 120 is coated on the electrode current collector 110 and a plain region where the electrode active material 120 is not coated on the electrode current collector 110. Here, the electrode tab 111 may be located in the plain region of the electrode current collector 110.

[0019] On the other hand, the electrode 130 may include a positive electrode 130a and a negative electrode 130b. The separator 140 separates the positive electrode 130a and the negative electrode 130b and electrically insulates them.

[0020] The positive electrode 130a may include a positive electrode current collector 110a and a positive electrode active material 120a provided on one surface of the positive electrode current collector 110a. Here, the positive electrode 130a may include a positive electrode blank area, which is a region where the positive electrode active material 120a is not laminated.

[0021] The positive electrode active material 120a may consist of lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or compounds and mixtures containing one or more of these.

[0022] The negative electrode 130b may include a negative electrode current collector 110b and a negative electrode active material 120b provided on one surface of the negative electrode current collector 110b. Here, the negative electrode 130b may include a negative electrode blank area, which is a region where the negative electrode active material 120b is not laminated.

[0023] The negative electrode active material 120b can consist of, for example, artificial graphite, lithium metal, lithium alloy, carbon, petroleum coke, activated carbon, graphite, silicon compounds, tin compounds, titanium compounds, or alloys thereof. Here, the negative electrode active material 120b may further include, for example, non-graphite-based SiO (silica) or SiC (silicon carbide).

[0024] On the other hand, the positive electrode current collector 110a and the negative electrode current collector 110b may include a polymer layer 112 and a first metal layer 113 and a second metal layer 114 laminated on both sides of the polymer layer 112 in the lamination direction D.

[0025] Here, the first metal layer 113 and the second metal layer 114 located on the positive electrode current collector 110a may include aluminum material, and the first metal layer 113 and the second metal layer 114 located on the negative electrode current collector 110b may include copper material.

[0026] Referring to Figure 3, the electrode current collector 110 includes an electrode tab 111 extending from its end. That is, the electrode tab 111 can be formed by cutting out the end of the electrode current collector 110.

[0027] Furthermore, the electrode current collector 110 includes a polymer layer 112 and a metal layer 115 laminated on both sides of the polymer layer 112 in the lamination direction D. Here, the metal layer 115 includes a first metal layer 113 laminated on one side of the polymer layer 112 and a second metal layer 114 laminated on the other side F2.

[0028] Here, the polymer layer 112 is a layer containing polymer material, and the metal layer 115 is a layer containing metal material. Therefore, the electrode current collector 110 is provided in a form in which the first metal layer 113 and the second metal layer 114 are laminated on both sides of the polymer layer 112, which can prevent the occurrence of fire due to excessive current density that occurs when it is made only of metal material. Furthermore, the electrode current collector 110 can have the first metal layer 113 and the second metal layer 114 formed thinly on both sides, which can reduce the risk of short circuits due to metal burrs etc. when breaking occurs.

[0029] Furthermore, the polymer layer 112 can be formed from a material containing, for example, PET (polyethylene terephthalate), PI (polyimide), or EN (polyethylene naphthalate).

[0030] On the other hand, the thickness of the first metal layer 113 can, for example, be the same as the thickness of the second metal layer 114.

[0031] On the other hand, the electrode current collector 110 can consist of a main body 117 on which an electrode active material is coated on its outer surface, and electrode tabs 111 extending from the main body 117.

[0032] On the other hand, referring to Figures 1 and 2, the electrode tabs 111 of the electrode current collector 110, each provided on a number of electrodes 130, can be gathered together to form a stack of tabs T.

[0033] Here, the tab stack T can be in a form where the ends of the electrode tabs 111 are brought together and welded to each other.

[0034] Referring to Figures 1 and 2, the electrode leads 200 are electrically connected to the electrode stack 100, and the electrode stack 100 can be electrically connected to external equipment.

[0035] The end of the electrode lead 200 can be welded and fixed to the outer surface of the metal clip 300. Here, the electrode lead 200 and the metal clip 300 are welded together, forming a welded joint P.

[0036] The metal clip 300 can wrap around the end of the tab laminate T. Here, the electrode laminate 100 and the electrode lead 200 can be electrically connected by connecting one side of the metal clip 300 to the electrode lead 200.

[0037] The metal clip 300 is provided with its side portions 301 and 303 bent relative to its central portion 302, and the side portions 301 and 303 of the metal clip 300 can contact the metal layer 115 of the electrode current collector 110 located on both sides of the outermost edge in the stacking direction D from the tab stack T.

[0038] Here, the metal clip 300 can be provided in a folded form that is shaped like a "U".

[0039] Here, one side of the metal clip 300 can be connected to the electrode lead 200.

[0040] On the other hand, the metal clip 300 and the metal layer 115 of the electrode current collector 110 may contain the same metal material.

[0041] Figure 5 is a cross-sectional view showing a first example of an electrode current collector in an electrode assembly according to an embodiment of the present invention, Figure 6 is a cross-sectional view showing a second example of an electrode current collector according to an embodiment of the present invention, and Figure 7 is a cross-sectional view showing a third example of an electrode current collector according to an embodiment of the present invention.

[0042] Referring to Figures 2 and 5-7, a protrusion 116 can be formed on the metal layer 115 of the electrode current collector 110 located at the outermost edge of the tab laminate T, projecting toward the metal clip 300. This increases the electrical contact between the metal layer 115 and the metal clip 300.

[0043] The protrusions 116 can be formed in the shape of a number of dots or lines along the surface of the metal layer 115 that faces the metal clip 300. Here, the protrusions 116 can be formed in the shape of a number of circular dots or in the shape of a number of parallel lines spaced at predetermined intervals.

[0044] Specifically, referring to Figure 5, the protrusions 116 can be formed in the shape of a number of circular dots, as a first example. Here, the circular dot-shaped protrusions 116 can be arranged in a number of rows and columns along the outer surface of the metal layer 115.

[0045] Referring to Figure 6, the protrusions 116' can, as a second example, be formed in a parallel line shape, arranged in a number of rows at predetermined intervals. Here, the protrusions 116' can be formed along the outer surface of the metal layer 115 located on the electrode tab 111' of the electrode current collector 110'.

[0046] Referring to Figure 7, the protrusions 116'' can, as a third example, be formed in a parallel line shape arranged in a number of rows at predetermined intervals. Here, the protrusions 116'' can be formed along the outer surface of the metal layer 115 located on the electrode tab 111'' of the electrode current collector 110''.

[0047] Referring to Figures 1 and 2, the electrode assembly 10 according to the embodiment of the present invention configured as described above has the effect of significantly improving the weldability of the electrode tabs 111 and electrode leads 200, as the ends of the tab stack T, in which the electrode tabs 111 of the electrode current collector 110, in which metal layers 115 are laminated on both sides of a polymer layer 112, are gathered together, are wrapped by a metal clip 300, and the electrode leads 200 are connected to the metal clip 300.

[0048] Secondary battery according to an embodiment The following describes a secondary battery according to an embodiment of the invention.

[0049] Figure 8 is a cross-sectional view showing a secondary battery including an electrode assembly according to an embodiment of the present invention.

[0050] Referring to Figures 1 to 3 and Figure 8, the secondary battery 1 according to an embodiment of the present invention includes an electrode assembly 10 and a battery case 20 housing the electrode assembly 10, the electrode assembly 10 includes an electrode stack 100 in which a number of electrodes 130 and separators 140 are alternately stacked, and electrode leads 200 electrically connected to the electrode stack 100, the electrode 130 includes an electrode current collector 110 including an electrode tab 111 extending to its end, the electrode current collector 110 includes a polymer layer 112 and a metal layer 115 stacked on both sides of the polymer layer 112 in the stacking direction D, the electrode tabs 111 of the electrode current collector 110 provided on each of the number of electrodes 130 form a tab stack T which is gathered together, and further includes a metal clip 300 which encloses the end of the tab stack T, and the electrode leads 200 are electrically connected to the electrode stack 100 by being connected to one side of the metal clip 300.

[0051] The secondary battery 1 according to the embodiment of the present invention relates to a secondary battery 1 including the electrode assembly 10 according to the embodiment described above. Therefore, this embodiment omits or briefly describes any content that overlaps with the embodiment described above.

[0052] More specifically, the battery case 20 has a housing formed inside that accommodates the electrode assembly 10. Here, the electrode stack 100 is housed in the battery case 20, and the electrode lead 200 has one side located inside the battery case 20 and connected to the electrode stack 100, while the other side can extend outside the battery case 20.

[0053] The electrode stack 100 is a power generation element capable of charging and discharging, and consists of a large number of electrodes 130 and separators 140 stacked alternately.

[0054] The electrode 130 includes an electrode current collector 110, which includes an electrode tab 111 extending to its end.

[0055] The electrode tabs 111 of the electrode current collector 110, each provided on a number of electrodes 130, can be assembled together to form a stack of tabs T.

[0056] The metal clip 300 can wrap around the end of the tab laminate T. Here, the electrode laminate 100 and the electrode lead 200 can be electrically connected by connecting one side of the metal clip 300 to the electrode lead 200.

[0057] The metal clip 300 is provided with its side portions 301 and 303 bent relative to the central portion 302, and the side portions 301 and 303 of the metal clip 300 can respectively contact the metal layer 115 of the electrode current collector 110 located on both sides of the outermost edge in the stacking direction D from the tab laminate T.

[0058] Method for manufacturing an electrode assembly according to an embodiment The following describes a method for manufacturing an electrode assembly according to an embodiment of the present invention.

[0059] Figure 9 is a perspective view showing the lamination process in the method for manufacturing an electrode assembly according to an embodiment of the present invention, and Figure 10 is a perspective view showing the tab formation process in the method for manufacturing an electrode assembly according to an embodiment of the present invention.

[0060] Referring to Figures 1, 2, 9, and 10, the method for manufacturing an electrode assembly according to an embodiment of the present invention includes a lamination process to form a current collector laminate S by laminating a metal layer 115 on both sides of a polymer layer 112, and a tab formation process to form electrode tabs 111 by notching the end portion of the current collector laminate S. The method also includes a current collector formation step to form an electrode current collector 110, an electrode laminate formation step to form an electrode laminate 100 by alternately laminating a number of electrodes 130 including the electrode current collector 110 and a separator 140, a tab assembly step to form a tab laminate T by bringing together the electrode tabs 111 of the electrode current collector 110 provided on each of the number of electrodes 130, a lead connection step to connect an electrode lead 200 to one side F1 of a metal sheet 300', and a folding step to form a metal clip 300 by folding the end of the tab laminate T so that the other side F2 of the metal sheet 300' wraps around it. Furthermore, the method for manufacturing an electrode assembly according to an embodiment of the present invention may further include a placement step, a stamping step, and a protrusion formation step.

[0061] The method for manufacturing an electrode assembly according to embodiments of the present invention relates to a method for manufacturing an electrode assembly for producing the electrode assembly 10 according to the above-described embodiments of the present invention and an electrode assembly 10 included in a secondary battery according to embodiments of the present invention.

[0062] Therefore, embodiments relating to the method for manufacturing an electrode assembly according to embodiments of the present invention will omit or briefly describe any content that overlaps with the embodiments of the present invention described above, and will focus on describing the differences.

[0063] More specifically, the current collector formation step includes a lamination process and a tab formation process.

[0064] Referring to Figure 9, the lamination process involves laminating metal layers 115 on both sides of the polymer layer 112 to form a current collector laminate S.

[0065] The lamination process involves depositing metal onto both sides of the polymer layer 112 in the lamination direction D to form a metal layer 115.

[0066] In the lamination process, a first metal layer 113 can be laminated on one surface of the polymer layer 112 in the lamination direction D, and a second metal layer 114 can be laminated on the other surface F2.

[0067] Here, the polymer layer 112 is a layer containing a polymer material, and the metal layer 115 is a layer containing a metal material.

[0068] Referring to Figure 10, the tab formation process involves notching the end portion of the laminate to form the electrode tab 111.

[0069] In other words, the tab formation process involves cutting open one side of a current collector laminate S in which a first metal layer 113 and a second metal layer 114 are laminated on both sides of a polymer layer 112, thereby forming an electrode tab 111 in a protruding form.

[0070] Furthermore, the tab formation process can be carried out by notching the current collector laminate S using a punch die or laser so that the electrode tab 111 is formed.

[0071] Referring to Figure 4, the electrode stacking step involves alternately stacking a number of electrodes 130, including an electrode current collector 110, and separators 140 to form the electrode stack 100.

[0072] Here, the electrode stack formation step allows for the alternating stacking of positive electrodes, separators 140, and negative electrodes. In this step, the electrode stack formation step allows for the separator 140 to be positioned at the outermost edge in the stacking direction D.

[0073] Figure 11 is a cross-sectional view showing the tab assembly step in a method for manufacturing an electrode assembly according to an embodiment of the present invention.

[0074] Referring to Figure 11, the tab assembly step forms a tab stack T by bringing together the electrode tabs 111 of the electrode current collector 110, each provided on a number of electrodes 130.

[0075] In other words, the tab assembly step can form a tab laminate T by welding under pressure the ends of the electrode tabs 111 extending from the electrode current collector 110 of the electrode 130 together.

[0076] Figure 12 is a cross-sectional view showing the lead connection step in a method for manufacturing an electrode assembly according to an embodiment of the present invention.

[0077] Referring to Figure 12, the lead coupling step involves coupling the electrode lead 200 to one side F1 of the metal sheet 300'.

[0078] The lead connection step can be performed by welding the electrode leads 200 to the metal sheet 300'.

[0079] Figure 13 is a cross-sectional view showing the placement step in a method for manufacturing an electrode assembly according to an embodiment of the present invention.

[0080] Referring to Figure 13, the placement step allows the tab laminate T to be placed on the first portion F21 on the other side F2 of the metal sheet 300' after the lead linking step.

[0081] Referring to Figure 13, the step of forming the protrusions allows for the formation of protrusions 116 that project toward the metal clip 300 on the metal layer 115 of the electrode current collector 110 located at the outermost edge of the tab laminate T in the stacking direction D, prior to the folding step.

[0082] The step of forming the protrusions allows for the formation of numerous protrusions 116 in the shape of dots or lines on the metal layer 115 along the surface facing the metal clip 300.

[0083] As an example, the step of forming the protrusion can be to deposit metal onto the surface of the metal layer 115 that faces the metal clip 300 to form the protrusion 116.

[0084] As another example, the step of forming the protrusion can be to position a dot or line-shaped metal strip between the metal layer 115 and the metal sheet 300' to form the protrusion 116.

[0085] Figure 14 is a cross-sectional view showing the folding step in a method for manufacturing an electrode assembly according to an embodiment of the present invention.

[0086] Referring to Figure 14, the folding step involves folding the end of the tab laminate T so that the other side F2 of the metal sheet 300' wraps around it, thereby forming the metal clip 300.

[0087] Furthermore, the folding step, after the placement step, allows the end of the electrode tab 111 to be enclosed in the second portion F22 on the other side F2 of the metal sheet 300'.

[0088] Furthermore, the folding step allows the metal sheet 300' to be folded such that the length L of the portion of the second part F22 facing the upper surface of the tab laminate T is 5 to 50 mm.

[0089] In the second portion F22 of the metal sheet 300', the length L of the portion facing the upper surface of the tab laminate T is formed to be 5 mm or more, which is the lower limit, enabling effective electrical contact, and is formed to be 50 mm or less, which facilitates folding of the metal sheet 300'.

[0090] Furthermore, the folding step allows the metal sheet 300' to be folded so that both sides of the metal sheet 300' contact the metal layers 115 of the electrode current collectors 110 located on both sides of the outermost edge in the stacking direction D in the tab laminate T.

[0091] On the other hand, the method for manufacturing an electrode assembly according to an embodiment of the present invention may further include a fixing step after the folding step, in which both sides of the metal sheet 300' and the metal layer 115 of the electrode current collector 110 are welded and fixed together.

[0092] Figure 15 is a cross-sectional view showing an example of the stamping step in the method for manufacturing an electrode assembly according to an embodiment of the present invention, and Figure 16 is a cross-sectional view showing another example of the stamping step in the method for manufacturing an electrode assembly according to an embodiment of the present invention.

[0093] Referring to Figures 15 and 16, the stamping step, after the folding step, stamps both outermost surfaces of the tab laminate T in the stacking direction D, thereby securing the metal clip 300 to the tab laminate T.

[0094] In this stamping step, the stamping means E presses both sides 301 and 303 of the metal clip 300 from both sides in the stacking direction, thereby fixing the metal clip 300 to the tab stack T.

[0095] On the other hand, referring to Figure 15, the stamping step can, for example, form the metal clip 300 so that both sides 301 and 303 are parallel to the outermost surface of the tab laminate T.

[0096] Referring also to Figure 16, the stamping step can, as another example, form convex protrusions 301a and 302b on both sides 301 and 303 of the metal clip 300 in the direction of the tab laminate T.

[0097] Although the present invention has been described in detail above with reference to specific embodiments, this is for the purpose of specifically illustrating the present invention, and the present invention is not limited thereto. It can be said that various implementations are possible within the technical concept of the present invention by persons with ordinary skill in the art.

[0098] Furthermore, the specific scope of protection of the invention will be clarified by the attached claims. [Explanation of Symbols]

[0099] 1 Secondary battery 10 Electrode assembly 20 Battery Cases 100 electrode stack 110, 110', 110'' electrode current collector 110a Positive electrode current collector 110b Negative electrode current collector 111, 111', 111' Electrode Tabs 112 Polymer layer 113 First Metal Layer 114 Second Metal Layer 115 Metal layer 116, 116', 116'' protrusion 117 Main unit 120 Electrode active material 120a Cathode active material 120b Anode active material 130 electrodes 130a positive electrode 130b negative electrode 140 Separator 200 electrode leads 300 Metal Clips 300' Metal Sheet D Stacking direction E Stamping method P Weld S Current collector laminate T-tab laminate

Claims

1. It includes an electrode stack in which multiple electrodes and separators are alternately stacked, and an electrode lead electrically connected to the electrode stack, The electrode includes an electrode current collector that includes an electrode tab extending to its end, The electrode current collector includes a polymer layer and metal layers laminated on both sides of the polymer layer in the lamination direction. The electrode tabs of the electrode current collector provided on each of the multiple electrodes form a stack of tabs that are brought together from one another. The invention further includes a metal clip that encloses the end of the tab stack, An electrode assembly in which the electrode lead is electrically connected to the electrode stack by being connected to one side of the metal clip.

2. The electrode assembly according to claim 1, wherein a protrusion is formed on the metal layer of the electrode current collector located at the outermost edge of the tab laminate, the protrusion being projected toward the metal clip.

3. The aforementioned protrusion is The electrode assembly according to claim 2, wherein a plurality of dots or lines are formed in the metal layer along the surface facing the metal clip.

4. The aforementioned protrusion is The electrode assembly according to claim 3, which is formed in the shape of multiple circular dots or in a parallel line shape with multiple dots arranged at predetermined intervals.

5. The electrode assembly according to claim 1, wherein the metal layer and the metal clip of the electrode current collector are made of the same metal material.

6. The electrode assembly according to claim 1, wherein the metal clip is provided in a U-shaped folded form.

7. The aforementioned metal clip is provided in a form in which both sides are bent relative to the central part, The electrode assembly according to any one of claims 1 to 6, wherein both sides of the metal clip are in contact with the metal layers of the electrode current collectors located on both sides of the outermost edge in the stacking direction in the tab laminate.

8. Includes an electrode assembly and a battery case that houses the electrode assembly, The electrode assembly includes an electrode stack in which multiple electrodes and separators are alternately stacked, and electrode leads electrically connected to the electrode stack. The electrode includes an electrode current collector that includes an electrode tab extending to its end, The electrode current collector includes a polymer layer and metal layers laminated on both sides of the polymer layer in the lamination direction. The electrode tabs of the electrode current collector provided on each of the multiple electrodes form a stack of tabs that are brought together from one another. The invention further includes a metal clip that encloses the end of the tab stack, A secondary battery in which the electrode leads are electrically connected to the electrode stack by being connected to one side of the metal clip.

9. The process includes a lamination process to form a current collector laminate by laminating metal layers on both sides of a polymer layer, and a tab formation process to form an electrode tab by notching the end portion of the current collector laminate, and a current collector formation step to form an electrode current collector, The steps include forming an electrode stack by alternately stacking a plurality of electrodes and separators, including the electrode current collector, A tab assembly step in which the electrode tabs of the electrode current collectors provided on each of the multiple electrodes are brought together to form a tab stack, A lead connection step involves connecting electrode leads to one side of a metal sheet, A method for manufacturing an electrode assembly, comprising a folding step of folding the end of the tab laminate so that the other side of the metal sheet wraps around it to form a metal clip.

10. The lead connection step involves welding the electrode leads to the metal sheet to connect them. The process further includes, after the lead connection step, a placement step of placing the tab laminate on the first portion on the other side of the metal sheet, The method for manufacturing an electrode assembly according to claim 9, wherein the folding step, after the setting step, surrounds the end of the electrode tab with a second portion on the other side of the metal sheet.

11. After the folding step mentioned above, A method for manufacturing an electrode assembly according to claim 10, further comprising a stamping step of stamping both sides of the metal clips located on both sides of the outermost edge of the tab laminate in the stacking direction, thereby fixing the metal clips to the tab laminate.

12. Before the aforementioned folding step, The method for manufacturing an electrode assembly according to claim 10, further comprising the step of forming a protrusion on the metal layer of the electrode current collector located at the outermost edge of the tab laminate in the stacking direction, the protrusion being directed toward the metal clip.

13. The method for manufacturing an electrode assembly according to claim 12, wherein the step of forming the protrusions is to form the protrusions on the metal layer in the shape of a plurality of dots or lines along the surface facing the metal clip.

14. The lamination process involves depositing metal onto both sides of the polymer layer in the lamination direction to form the metal layer. The method for manufacturing an electrode assembly according to claim 12, wherein the step of forming the protrusion is to deposit metal onto the surface of the metal layer facing the metal clip to form the protrusion.

15. The method for manufacturing an electrode assembly according to claim 12, wherein in the step of forming the protrusion, the protrusion is formed by positioning a dot or line-shaped metal strip between the metal layer and the metal sheet, and then the folding step is performed.

16. The aforementioned folding step is, A method for manufacturing an electrode assembly according to claim 10, wherein the second portion of the metal sheet to be folded is folded such that the length of the portion facing the upper surface of the tab laminate is 5 mm or more and 50 mm or less.

17. The aforementioned folding step is, A method for manufacturing an electrode assembly according to any one of claims 9 to 16, wherein both sides of the metal sheet are bent so as to contact the metal layers of the electrode current collectors located on both sides of the outermost edge in the stacking direction in the tab laminate.

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