Electrode unit and method for manufacturing same

Abstract

The present invention relates to an electrode assembly, and the electrode assembly according to an aspect of the present invention may comprise: a first electrode comprising a first body portion coated with a first electrode active material and a first tab portion extending outwardly from an edge of the first body portion; a second electrode including a second body portion stacked on one surface of the first body portion and coated with a second electrode active material, and an uncoated portion disposed on an edge of the second body portion and overlapping an edge of the first body portion; and a separator interposed between the first electrode and the second electrode, in which the first electrode may further include an extension portion provided at an edge of the first body portion and protruding to an outer side of the uncoated portion.

Description

TECHNICAL FIELD

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Korean Patent Application No. 10-2023-0135425, filed on October 11, 2023, in the Republic of Korea, the disclosure of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present disclosure relates to an electrode assembly and a method for manufacturing the same, and more particularly, to an electrode assembly that can be used in a secondary battery and a method for manufacturing the same. BACKGROUND

[0004] In general, types of secondary batteries include nickel-cadmium batteries, nickel-hydrogen batteries, lithium-ion batteries, and lithium-ion polymer batteries. These secondary batteries are not only applied and used in small products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, portable game devices, power tools, and electric bicycles, but also applied and used in large products requiring high power such as electric vehicles or hybrid vehicles, power storage devices storing surplus generated power or renewable energy, and power storage devices for backup.

[0005] To manufacture such a secondary battery, first, an electrode active material slurry is applied to an electrode current collector to manufacture an electrode, and then the electrode is stacked on both sides of a separator to form an electrode stack having a predetermined shape. Also, the electrode stack is accommodated in a battery case, an electrolyte solution is injected, and then the battery case is sealed.

[0006] The electrode stack is classified into various types. For example, there are a simple stacking type in which a positive electrode, a separator, and a negative electrode are continuously and simply alternately stacked, a lamination and stacking type (L&S) in which an electrode assembly is manufactured using unit electrodes and separators first and then the electrode assembly is stacked, a stacking and folding type (S&F) in which a plurality of unit electrodes or electrode units are spaced apart and attached to one surface of a separator sheet longer on one side, and the separator sheet is repeatedly folded in the same direction from one end portion, and a Z-folding type in which each of a plurality of electrodes or electrode units is alternately attached to one surface of a separator sheet longer on one side and the other surface, and the separator sheet is folded in a specific direction from one end portion and then alternately and repeatedly folded in the opposite direction.

[0007] At this time, the electrode assembly (or electrode unit) can be formed by cutting an electrode sheet coated with an electrode active material into a predetermined size, and then stacking the manufactured electrodes with a separator interposed therebetween. To verify whether the electrodes are relatively correctly stacked (or positioned), a gap between the stacked electrodes is measured. Typically, to check the gap, a distance between an edge of an electrode stacked on an upper side and an edge of an electrode stacked on a lower side is measured, and if the measured distance is within a predetermined range, it is determined that the electrodes are correctly stacked (i.e., it is determined that there is no defect).

[0008] Meanwhile, an edge of the electrode can be provided with an uncoated portion to which the electrode active material is not applied. Typically, the uncoated portion is provided along an edge of both sides in a length direction (or a width direction) of the electrode. Such an uncoated portion can perform various functions.

[0009] As an example, when the electrode active material is applied (or coated) to a metal sheet that is a current collector, the uncoated portion can improve island defects caused by aggregation or splashing of excess electrode active material or foreign substances on the metal sheet. As another example, the uncoated portion can serve as a portion that is cut in a notch opening process of the electrode, thereby preventing a region to which the electrode active material is applied from being damaged by the notch opening process. These functions of the uncoated portion can be more effectively performed as the width of the uncoated portion extending from the edge of the electrode becomes wider.

[0010] However, if the uncoated portion of the electrode becomes wider, the measured gap between the stacked electrodes can be different from the actual gap, which can cause a false judgment on whether the electrode assembly has a defect. More specifically, the wider the uncoated portion of the electrode stacked on the upper side, the more likely it is that an edge of another electrode disposed on the lower side is covered by the uncoated portion. This can hinder the gap between the stacked electrodes from being accurately measured, which can cause a false judgment on whether there is a defect. The possibility of such a false judgment has become an issue of limiting the size of the uncoated portion, thereby limiting improvement in island defects. SUMMARY

[0011] TECHNICAL PROBLEM

[0012] The present disclosure is designed to solve the problems of the related art, and thus, the present disclosure aims to provide an electrode assembly in which a gap between stacked electrodes can be accurately measured while island defects can be improved, and a method for manufacturing the same.

[0013] The technical problems to be solved by the present disclosure are not limited to the above-mentioned problems, and those of ordinary skill in the art can clearly understand other problems not mentioned herein from the following description of the present disclosure.

[0014] TECHNICAL SOLUTION

[0015] According to an aspect of the disclosure, an electrode assembly is disclosed, the electrode assembly including: a first electrode including a first body portion coated with a first electrode active material and a first tab portion extending outward from an edge of the first body portion; a second electrode including a second body portion stacked on one surface of the first body portion and coated with a second electrode active material, and an uncoated portion provided on an edge of the second body portion and overlapping the edge of the first body portion; and a separator interposed between the first electrode and the second electrode, wherein the first electrode further includes an extension portion provided on the edge of the first body portion and protruding outward with respect to the uncoated portion.

[0016] At this time, the edge of the first body portion and the uncoated portion can extend in parallel to each other.

[0017] At this time, the edge of the uncoated portion can form a predetermined interval in a width direction from the edge of the first body portion.

[0018] At this time, the edge of the uncoated portion can be positioned further outward than the edge of the first body portion.

[0019] At this time, the extension portion can extend from the first body portion by a length shorter than a length by which the first tab portion extends from the first body portion.

[0020] At this time, the first tab portion and the extension portion can be disposed at a predetermined interval apart along the edge of the first body portion.

[0021] At this time, the second electrode can include a second tab portion provided on the edge of the second body portion, and the second tab portion and the extension portion can be spaced apart from each other so as not to overlap in a stacking direction of the first body portion and the second body portion.

[0022] At this time, the first tab portion can extend from one side of the first body portion, and the extension portion can extend from the other side of the first body portion.

[0023] At this time, the first tab portion and the extension portion can be staggered with respect to a length direction of the first body portion.

[0024] At this time, the extension portion can have a film or sheet shape extending in parallel to the first body portion.

[0025] At this time, the extension portion can include a first side portion parallel to the edge of the second body portion.

[0026] At this time, the extension portion can further include a second side portion connecting the first side portion and the first body portion and being perpendicular or inclined with respect to the first side portion.

[0027] At this time, the second electrode can include a protective layer disposed on an outer surface of the uncoated portion.

[0028] According to another aspect of the present disclosure, there is provided a method for manufacturing an electrode assembly, the method including a step of providing a first electrode including a first body portion in the shape of a film or sheet to which a first electrode active material is applied, and a first tab portion and an extension portion extending from an edge of the first body portion; a step of providing a second electrode in which a second electrode active material is applied to at least one region; a step of forming an electrode assembly by stacking the first electrode and the second electrode with a separator interposed therebetween; and a step of determining whether the electrode assembly is defective based on information about a relative position of the extension portion projecting outward with respect to the second electrode.

[0029] At this time, in the step of providing the second electrode, a second electrode including a second body portion in the shape of a film or sheet coated with a second electrode active material and an uncoated portion disposed on an edge of the second body portion can be provided, and the step of determining whether the electrode assembly is defective can include a step of acquiring information about a relative position between the extension portion and the second body portion.

[0030] At this time, the step of acquiring information about the relative position between the extension portion and the second body portion can include a step of identifying an edge of an end portion side of the extension portion in the extension direction; a step of identifying an edge of the second body portion; and a step of measuring a reference distance that is a distance between the edge of the extension portion and the edge of the second body portion.

[0031] At this time, the step of determining whether the electrode assembly is defective can include a step of comparing the reference distance with a length of the extension portion extending from the first body portion; and a step of determining whether the second body portion protrudes to an outer side of the edge of the first body portion based on a comparison result.

[0032] At this time, in the step of determining whether the second body portion protrudes, if the reference distance is greater than the length of the extension portion, it can be determined that the second body portion does not protrude to the outer side of the first body portion.

[0033] At this time, in the step of providing the second electrode, a second electrode including a second body portion in the shape of a film or sheet coated with a second electrode active material and a second tab portion extending from an edge of the second body portion can be provided, and in the step of stacking the first electrode and the second electrode, the second tab portion and the extension portion can be disposed not to overlap in a direction in which the first electrode and the second electrode are stacked.

[0034] Advantageous effects

[0035] According to the electrode assembly and the method for manufacturing the same according to one aspect of the disclosure, the first electrode includes an extension portion extending outward from a first body portion, and thus, even if an edge of the first body portion is covered by an uncoated portion of a second electrode stacked on an upper side of the first electrode, a gap between the first electrode and the second electrode can be accurately measured based on a relative position between the extension portion and the second electrode.

[0036] Accordingly, in the electrode assembly and the method for manufacturing the same according to one aspect of the disclosure, the uncoated portion of the second electrode can have a wider width, thereby further improving the effect of improving island defects.

[0037] Effects obtained by the disclosure are not limited to the above-mentioned effects, and other effects not mentioned herein can be clearly understood by a person of ordinary skill in the art from the present specification and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a perspective view of an electrode assembly according to an embodiment of the disclosure when viewed from above. At this time, in order to describe the disclosure, a partition is represented in a dotted line, and a configuration seen through the partition is represented in a solid line.

[0039] Figure 2 is an exploded perspective view of an electrode assembly according to an embodiment of the disclosure.

[0040] Figure 3 is a plan view of an electrode assembly according to an embodiment of the disclosure. At this time, in order to describe the disclosure, a partition is not shown, and a configuration seen through a second electrode is represented in a dotted line.

[0041] Figure 4 is a cross-sectional view taken along line I-I of Figure 1 .

[0042] Figure 5 is a plan view of a first electrode of an electrode assembly according to another embodiment of the disclosure when viewed from above.

[0043] Figure 6 is a plan view of a first electrode of an electrode assembly according to still another embodiment of the disclosure when viewed from above.

[0044] Figure 7 is a flowchart of a method for manufacturing an electrode assembly according to an embodiment of the disclosure.

[0045] Figure 8 is a flowchart of a sub-step S400 of Figure 7 .

[0046] Figure 9is a plan view of an electrode assembly according to a comparative example. At this time, in order to describe the present disclosure, the separator is not shown, and the configuration seen through the second electrode is indicated in a dotted line. DETAILED DESCRIPTION

[0047] The preferred embodiments of the present disclosure will be described in sufficient detail to enable those skilled in the art to readily practice the present disclosure. However, the present disclosure can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, the embodiments provided herein are meant to be illustrative only and should not be taken as limiting the scope of the present disclosure.

[0048] In order to clearly describe the present disclosure, irrelevant descriptions or detailed descriptions of related known technologies that can unnecessarily obscure the gist of the present disclosure are omitted, and in attaching reference numerals to elements in each drawing, the same or similar reference numerals are attached to the same or similar elements throughout the present disclosure.

[0049] Further, it should be understood that the terms or words used in the present disclosure and the appended claims should not be interpreted as limited to general and dictionary meanings and should be interpreted based on the meanings and concepts corresponding to the technical aspects of the present disclosure on the basis of the principle that the inventor is allowed to define appropriate terms in order to best explain the present disclosure.

[0050] Figure 1 is a perspective view of an electrode assembly according to an embodiment of the present disclosure when viewed from above. At this time, in order to describe the present disclosure, the separator is indicated in a dotted line, and the configuration seen through the separator is indicated in a solid line. Figure 2 is an exploded perspective view of an electrode assembly according to an embodiment of the present disclosure. Figure 3 is a plan view of an electrode assembly according to an embodiment of the present disclosure. At this time, in order to describe the present disclosure, the separator is not shown, and the configuration seen through the second electrode is indicated in a dotted line. Figure 4 is a cross-sectional view taken along line I-I of Figure 1 At this time, in the drawings, each component of the secondary battery according to the first embodiment of the present disclosure is schematically shown, and the size of the components, the thickness of the lines, etc. can be exaggerated for ease of understanding.

[0051] In Figures 1 to 4 , an electrode assembly 1 according to the first embodiment of the present disclosure is disclosed. The electrode assembly 1 according to the first embodiment of the present disclosure is an assembly disposed inside a secondary battery and which can release electric energy to the outside or be charged by receiving electric energy from the outside.

[0052] In the present embodiment, the electrode assembly 1 can have a structure in which the first electrode 10 and the second electrode 20 are stacked in a vertical direction (Z-axis direction) with the separator 30 interposed therebetween. At this time, the first electrode 10 disposed on the lower side can have the extension portion 16 extending outward. Such an extension portion 16 can further protrude outward than the uncoated portion 24 of the second electrode 20 disposed on the upper side.

[0053] Therefore, in the electrode assembly 1 according to the present embodiment, even if the edge of the first electrode 10 is covered by the uncoated portion 24 of the second electrode 20, the gap between the second electrode 20 and the first electrode 10 can be measured based on information about the relative position between the second electrode 20 and the extension portion 16.

[0054] Therefore, in the present embodiment, the uncoated portion 24 of the second electrode 20 can be formed to have a wider width w regardless of whether it covers the edge of the first electrode 10, thereby maximizing the effects that can be achieved by the uncoated portion 24.

[0055] As an example, since the uncoated portion 24 of the second electrode 20 is disposed in a wider area, island defects of the second electrode 20 can be further improved. As another example, the uncoated portion 24 of the second electrode 20 can serve as a portion that is cut in a notching process, thereby preventing the second body portion 22 to which the electrode active material is applied from being damaged by the notching process. At this time, the notching process can be a laser notching process, but is not limited thereto.

[0056] Hereinafter, components according to the first embodiment of the present disclosure will be described in more detail. Referring to Figures 1 to 4 , the electrode assembly 1 according to the first embodiment of the present disclosure can include a plurality of electrodes stacked with each other. As illustrated, the plurality of electrodes can include the first electrode 10 and the second electrode 20. At this time, the first electrode 10 and the second electrode 20 can have different polarities. For example, the first electrode 10 can be a negative electrode, and the second electrode 20 can be a positive electrode.

[0057] According to the present embodiment, the first electrode 10 can include a first body portion 12. The first body portion 12 can be provided as a rectangular film or a sheet-shaped member in which a first electrode active material is applied to a thin metal plate. A first side portion 12a extending in one direction, for example, in the X-axis direction in the drawing, can be provided on an edge side of the first body portion 12. The shape of the first body portion 12 can be appropriately modified as needed.

[0058] At this time, the thin metal plate can be made of aluminum (Al) or copper (Cu). The first electrode active material can include lithium cobalt oxide (LCO), lithium manganese oxide (LMO), nickel cobalt manganese (NCM), nickel cobalt aluminum (NCA), lithium iron phosphate (LFP), graphite (C), silicon (Si), etc. However, the type of the material forming the thin metal plate and the type of the electrode active material are not limited to those described above.

[0059] Referring to Figures 1 to 3 , the first electrode 10 of the electrode assembly 1 according to the first embodiment of the disclosure can include a first tab portion 14. The first tab portion 14 is configured to function as a junction allowing the first body portion 12 to be electrically connected to an external power source or a load.

[0060] As illustrated, the first tab portion 14 can extend outward from the first side portion 12a of the first body portion 12. The first tab portion 14 can be provided as a rectangular film or sheet having a smaller width than the first body portion 12. The first tab portion 14 can be formed as an edge of a sheet to which the first electrode active material is applied is cut through a slitting process. The shape of the first tab portion 14 can be appropriately modified as needed.

[0061] Meanwhile, according to the first embodiment of the disclosure, the first tab portion 14 can include a first portion 14a and a second portion 14b. Also, the first electrode active material can be applied to either one of the first portion 14a and the second portion 14b, and the first electrode active material can not be applied to the other, such that the thin metal plate can be exposed to the outside.

[0062] Accordingly, a shoulder line 14c can be formed between the first portion 14a and the second portion 14b to separate the first portion 14a and the second portion 14b. In the present embodiment, the second portion 14b is provided at an end portion side of the first tab portion 14, and the first portion 14a can be provided between the first body portion 12 and the second portion 14b to connect them. Also, the first electrode active material is applied to the first portion 14a, the first electrode active material is not applied to the second portion 14b, and the shoulder line 14c can extend in parallel to a width direction (X-axis direction) of the first body portion 12.

[0063] Meanwhile, referring again to Figures 1 to 4 , the first electrode 10 according to the first embodiment of the disclosure can include an extension portion 16. In the present embodiment, the extension portion 16 is a configuration for measuring a gap between the first electrode 10 and a second electrode 20. A detailed description of the function of the extension portion 16 will be described later together with the second electrode 20.

[0064] The extension portion 16 can be provided on the edge of the first body portion 12. As shown, the extension portion 16 can extend outward from the first side portion 12a of the first body portion 12. At this time, the extension portion 16 can be provided to be spaced apart from the first tab portion 14 at a predetermined interval in the direction (X-axis direction) in which the first side portion 12a extends.

[0065] According to this embodiment, the extension portion 16 can be provided in the form of a rectangular film or sheet. Also, a reference side portion 16a extending in the direction (X-axis direction) parallel to the first side portion 12a of the first body portion 12 can be provided at the end portion side of the extension portion 16.

[0066] The reference side portion 16a can be a reference for measuring the gap between the first electrode 10 and the second electrode 20. At this time, the length of the reference side portion 16a can be extended to be sufficient to be recognized by a predetermined sensor or detection device.

[0067] Meanwhile, the extension portion 16 can extend outward from the first side portion 12a of the first body portion 12 by a predetermined length L1. At this time, L1 can represent the distance between a reference line L-12a parallel to the first side portion 12a and a reference line L-16a parallel to the reference side portion 16a, as shown in Figure 3 .

[0068] At this time, the length L1 by which the extension portion 16 extends outward from the first body portion 12 can be shorter than the length L2 by which the first portion 14a to which the first electrode active material is applied in the first tab portion 14 extends outward from the first body portion 12. At this time, L2 can represent the distance between the reference line L-12a parallel to the first side portion 12a and a reference line L-14c parallel to the shoulder line 14c, as shown in Figure 3 .

[0069] Referring again to Figures 1 to 4 , the second electrode 20 of the electrode assembly 1 according to the first embodiment of the disclosure can include a second body portion 22. The second body portion 22 can be provided in the shape of a rectangular film or sheet in which a second electrode active material C (shown in Figure 4 ) is applied to a thin metal plate F (shown in Figure 4 ).

[0070] In the present embodiment, a second side portion 22a can be provided on the edge side portion of the second body portion 22. The second side portion 22a can be the side portion closest to the first side portion 12a of the first electrode 10 among the side portions provided on the edge side portion of the second body portion 22. Also, the second side portion 22a can extend parallel to the first side portion 12a. The shape of the second body portion 22 can be appropriately modified as needed.

[0071] At this time, the thin metal plate can be made of aluminum (Al) or copper (Cu). The second electrode active material can include lithium cobalt oxide (LCO), lithium manganese oxide (LMO), nickel cobalt manganese (NCM), nickel cobalt aluminum (NCA), lithium iron phosphate (LFP), graphite (C), silicon (Si), etc. However, the type of the material forming the thin metal plate and the type of the electrode active material are not limited to those described above.

[0072] Meanwhile, it can be determined whether the electrode assembly 1 is defective according to the relative positional relationship between the first body portion 12 and the second body portion 22. More specifically, when viewed in the stacking direction (Z-axis direction) of the first electrode 10 and the second electrode 20, if the second body portion 22 is positioned inside the edge of the first body portion 12, the electrode assembly 1 can be regarded as non-defective, and if the second body portion 22 is positioned outside the edge of the first body portion 12, the electrode assembly 1 can be regarded as defective. To determine this, the gap between the first electrode 10 and the second electrode 20 can be measured.

[0073] This is because, if the second body portion 22 protrudes outward with respect to the edge of the first body portion 12, the insulation between the first electrode 10 and the second electrode 20 cannot be sufficiently ensured, and thus the electrode assembly 1 can not operate with its original function or can cause a stability problem.

[0074] Meanwhile, referring again to Figures 1 to 4 , the second electrode 20 of the electrode assembly 1 according to the first embodiment of the disclosure can include an uncoated portion 24. The uncoated portion 24 can mean a portion in which the thin metal plate is exposed to the outside since the second electrode active material is not applied thereto.

[0075] The uncoated portion 24 can be provided on the edge side of the second body portion 22. In the present embodiment, since the second electrode active material C (shown in Figure 4 ) is applied to the central portion of the thin metal plate F (shown in Figure 4 ) rather than the edge portion, the central portion of the thin metal plate becomes the second body portion 22, and the uncoated portion 24 can be provided on the edge side of the second body portion 22.

[0076] In the present embodiment, the uncoated portion 24 can extend outward from the second side 22a of the second body portion 22. Accordingly, the uncoated portion 24 can have a predetermined width w in the outward direction of the second body portion 22. Also, the uncoated portion 24 can extend in a direction parallel to the second side 22a. Of course, the uncoated portion 24 can also be provided on the other side 22b of the second body portion 22 opposite the second side 22a.

[0077] According to this embodiment, the uncoated portion 24 can perform a predetermined function. As an example, the uncoated portion 24 can improve island-like defects that can be caused by splashing of the electrode active material or foreign substances during a process of applying the second electrode active material to the thin metal plate. As another example, the uncoated portion 24 can be used as a portion that is cut in a notching process for forming an appearance of the second electrode 20, thereby preventing the second body portion 22 from being damaged by the notching process.

[0078] At this time, in the present embodiment, the uncoated portion 24 of the second electrode 20 can be disposed to overlap the first side portion 12a of the first electrode 10 in the stacking direction (Z-axis direction). Here, the uncoated portion 24 overlapping the first side portion 12a can mean that the uncoated portion 24 covers at least a portion of the first side portion 12a.

[0079] Also, in the present embodiment, the extension portion 16 of the first electrode 10 described above can further protrude outward than the uncoated portion 24. Therefore, the reference side portion 16a disposed at the end portion side of the extension portion 16 can not overlap the uncoated portion 24 in the stacking direction. In other words, the reference side portion 16a can not be covered by the uncoated portion 24.

[0080] In the present embodiment, since the extension portion 16 of the first electrode 10 protrudes outward with respect to the uncoated portion 24 of the second electrode 20, the gap between the first electrode 10 and the second electrode 20 can be indirectly measured using information about the relative positions of the extension portion 16 and the second body portion 22.

[0081] In this way, since the first side portion 12a of the first body portion 12 can be covered in the present embodiment, the uncoated portion 24 of the second electrode 20 can have a wider width w. In other words, the uncoated portion 24 can be formed in a wider area.

[0082] Therefore, in the electrode assembly 1 according to the first embodiment of the present disclosure, the function of the uncoated portion 24 can be maximized. For example, the effect of improving island-like defects of the electrode assembly 1 or the effect of preventing the second body portion 22 from being damaged by a notching process can be further improved.

[0083] The method for measuring the gap based on the relative positions of the extension portion 16 and the second body portion 22 according to this embodiment will be described later together with the method for manufacturing the electrode assembly according to the embodiments of the present disclosure.

[0084] Meanwhile, referring to Figures 2 to 4 , the second electrode 20 of the electrode assembly 1 according to the first embodiment of the present disclosure can include a protective layer 24b. In the present embodiment, the protective layer 24b can be disposed on an outer surface of the uncoated portion 24.

[0085] At this time, the protective layer 24b can be located at a portion of the outer surface of the uncoated portion 24 adjacent to the second body portion 22, as shown in Figure 4 The protective layer 24b can extend from the outer surface of the uncoated portion 24 along the second side portion 22b of the second body portion 22.

[0086] Such a protective layer 24b can perform a predetermined function. For example, the protective layer 24b can perform a function of protecting the second body portion 22 to which the second electrode active material is applied during the aperture cutting process.

[0087] In the present embodiment, the protective layer 24b can be formed by coating (or applying) a predetermined material on the outer surface of the uncoated portion 24. The material forming the protective layer 24b can be appropriately selected depending on the function of the protective layer 24b. As an example, the material can be polyvinylidene fluoride (PVDF), but is not limited thereto.

[0088] Referring again to Figures 1 to 3 , the second electrode 20 of the electrode assembly 1 according to the first embodiment of the present disclosure can include a second tab portion 26. The second tab portion 26 is configured to function as a junction allowing the second body portion 22 to be electrically connected to an external power source or load.

[0089] In the present embodiment, the second tab portion 26 can extend outward from the uncoated portion 24. Also, as shown, the second tab portion 26 can be provided as a rectangular film or sheet having a smaller width than the second body portion 22. The shape of the second tab portion 26 can be appropriately modified as needed.

[0090] At this time, in the present embodiment, the second tab portion 26 can be spaced apart from the extension portion 16 of the above-described first electrode 10 in a direction (X-axis direction or Y-axis direction) perpendicular to the stacking direction (Z-axis direction). This is to prevent the extension portion 16 of the first electrode 10 from being covered by the second tab portion 26 of the second electrode 20.

[0091] Meanwhile, the uncoated portion 24 and the second tab portion 26 of the above-described second electrode 20 can be formed as the edges of the sheet to which the second electrode active material is applied are cut through the aperture cutting process.

[0092] Referring again to Figure 1 and Figure 2 , the electrode assembly 1 according to the first embodiment of the present disclosure can include a separator 30. In the present embodiment, the separator 30 is configured to secure stability of the electrode assembly 1 by preventing the first electrode 10 and the second electrode 20 stacked with each other from contacting each other.

[0093] In the present embodiment, the partition 30 can be provided as a rectangular film or sheet interposed between the first electrode 10 and the second electrode 20. At this time, the width and length of the partition 30 can be greater than those of the first body portion 12 and the second body portion 22. Thereby, insulation between the first electrode 10 and the second electrode 20 can be sufficiently ensured. The shape of the partition 30 can be appropriately modified as needed.

[0094] At this time, the partition 30 can be made of polyethylene, polypropylene, or the like, but the material constituting the partition 30 is not particularly limited as long as it can ensure insulation between the first electrode 10 and the second electrode 20.

[0095] As described above, even in the electrode assembly 1 according to the present embodiment in which the edge of the first body portion 12 of the first electrode 10 is covered, the gap between the first electrode 10 and the second electrode 20 can be measured, and thus the uncoated portion 24 of the second electrode 20 can be formed to have a wider width or area. Thereby, the function of the uncoated portion 24 can be more effectively exerted.

[0096] Hereinafter, electrode assemblies according to other embodiments of the present disclosure will be described with different drawings. Figure 5 is a plan view of a first electrode of an electrode assembly according to another embodiment of the present disclosure when viewed from above. Figure 6 is a plan view of a first electrode of an electrode assembly according to still another embodiment of the present disclosure when viewed from above. At this time, in the drawing, a second electrode of a secondary battery according to other embodiments of the present disclosure is schematically shown, and the size of components, the thickness of lines, and the like can be exaggerated for convenience of understanding. Also, the same reference numerals as in the drawings shown above denote the same members performing the same functions.

[0097] According to embodiments of the present disclosure, the extension portion of the first electrode can have various shapes. As an example, Figure 5 A first electrode 110 of an electrode assembly according to another embodiment of the present disclosure is disclosed.

[0098] Referring to Figure 5 In the present embodiment, the extension portion 116 can extend from the first side portion 12a of the first body portion 12. A reference side portion 116a parallel to the first side portion 12a can be provided on the edge of the end portion side of the extension portion 116. At this time, the reference side portion 116a can extend to a length sufficient to be recognized by a sensor or detection device for sensing it.

[0099] In the present embodiment, the first connecting side portion 116b and the second connecting side portion 116c can be respectively provided on the edges of the side portions of the extension portion 116. The first connecting side portion 116b can connect one end portion of the reference side portion 116a and the first side portion 12a to each other. Also, the first connecting side portion 116b can extend obliquely with respect to the reference side portion 116a. The second connecting side portion 116c can connect the other end portion of the reference side portion 116a and the first side portion 12a to each other. Also, the second connecting side portion 116c can extend obliquely with respect to the reference side portion 116a.

[0100] At this time, the first connecting side portion 116b and the second connecting side portion 116c can be obliquely inclined toward the end portion side of the extension portion 116 so as to become close to each other. In other words, the extension portion 116 can have a trapezoidal shape. Therefore, the extension portion of the electrode assembly according to the embodiments of the present disclosure can be provided in various shapes.

[0101] According to the embodiments of the present disclosure, the extension portion of the first electrode can be provided at various positions. As an example, Figure 6 A first electrode 210 of an electrode assembly according to still another embodiment of the present disclosure is disclosed.

[0102] Referring to Figure 6 In the present embodiment, the first tab portion 14 can be provided on the first side portion 12a of the first body portion 12. At this time, an extension portion 216 can be provided on the other side portion 12b of the first body portion 12 opposite to the first side portion 12a.

[0103] In the present embodiment, the extension portion 216 can extend outward from the other side portion 12b of the first body portion 12. At this time, the extension portion 216 can be provided to be misaligned with the first tab portion 14 in the length direction (Y-axis direction) of the first body portion 12.

[0104] This is to prevent the extension portion 216 from being covered by the second tab portion of the second electrode, since the second tab portion of the second electrode can be provided parallel to the first tab portion 14 in the length direction of the first body portion 12.

[0105] Therefore, the extension portion of the electrode assembly according to the embodiments of the present disclosure can be located at various portions of the edge of the first body portion 12, as long as it can not be covered by the second tab portion of the second electrode.

[0106] Hereinafter, a method for manufacturing an electrode assembly according to the embodiments of the present disclosure will be described with different drawings. Figure 7 is a flowchart of a method for manufacturing an electrode assembly according to the embodiments of the present disclosure. Figure 8 is Figure 7a flowchart of the sub-steps S400. Figure 9 is a plan view of an electrode assembly according to a comparative example. At this time, for the purpose of describing the present disclosure, the separator is not shown, and the configuration seen through the second electrode is indicated in a dotted line.

[0107] Referring to Figure 1 , Figure 2 and Figure 7 , in the method for manufacturing an electrode assembly according to the embodiment of the present disclosure, a first electrode 10 is provided (S100). At this time, the first electrode 10 provided in the step S100 can be the first electrode 10 of the electrode assembly 1 according to the first embodiment of the present disclosure.

[0108] That is, the first electrode 10 provided in the step S100 can include a first body portion 12 to which a first electrode active material is applied, a first tab portion 14 extending outward from a first side portion 12a provided on an edge side of the first body portion 12, and an extension portion 16 spaced apart from the first tab portion 14 and extending outward from the first side portion 12a. However, the structure of the first electrode 10 provided in the step S100 is not particularly limited as long as it includes the extension portion 16.

[0109] Referring to Figures 1 to 3 and Figure 7 , in the method for manufacturing an electrode assembly according to the embodiment of the present disclosure, the first electrode 10 is provided (S100), and the second electrode 20 is provided (S200). At this time, the order of the steps S100 and S200 is not particularly limited.

[0110] According to the embodiment, the second electrode 20 provided in the step S200 can be the second electrode 20 of the electrode assembly 1 according to the first embodiment of the present disclosure. That is, the second electrode 20 can include a second body portion 22 to which a second electrode active material is applied, an uncoated portion 24 extending from a second side portion 22a provided on an edge of the second body portion 22 to have a predetermined width w, and a second tab portion 26 extending from the uncoated portion 24. However, the structure of the second electrode 20 provided in the step S200 is not particularly limited.

[0111] Referring again to Figure 1 , Figure 2 and Figure 7 , in the method for manufacturing an electrode assembly according to the embodiment of the present disclosure, the first electrode 10 provided in the step S100 and the second electrode 20 provided in the step S200 are stacked with the separator 30 interposed therebetween to form the electrode assembly 1 (S300). At this time, in the step S300, the second electrode 20 can be disposed above the first electrode 10.

[0112] At this time, according to the method for manufacturing an electrode assembly according to the embodiment of the present disclosure, in step S300, the extension portion 16 of the first electrode 10 and the second tab portion 26 of the second electrode 20 can be arranged not to overlap each other in the stacking direction (Z-axis direction).

[0113] Here, the fact that the extension portion 16 and the second tab portion 26 do not overlap each other can mean that the extension portion 16 is not covered by the second tab portion 26. This is in order to enable a sensor or inspection device disposed above the electrode assembly 1 to recognize the extension portion 16 of the first electrode 10 in step S400 to be described later.

[0114] Referring to Figures 1 to 3 and Figure 7 In the method for manufacturing an electrode assembly according to the embodiment of the present disclosure, the first electrode 10 and the second electrode 20 are stacked to form the electrode assembly 1 (S300), and it is determined whether the formed electrode assembly 1 is defective (S400).

[0115] In the present embodiment, it can be determined whether the electrode assembly 1 is defective based on the relative position between the first body portion 12 of the first electrode 10 and the second body portion 22 of the second electrode 20. More specifically, when viewed in the stacking direction (Z-axis direction) of the first electrode 10 and the second electrode 20, if the second body portion 22 is positioned inside the edge of the first body portion 12, it can be determined that the electrode assembly 1 is not defective, and if the second body portion 22 protrudes outside the edge of the first body portion 12, it can be determined that the electrode assembly 1 is defective.

[0116] At this time, in step S400 of the method for manufacturing an electrode assembly according to the embodiment of the present disclosure, in order to determine whether the electrode assembly 1 is defective, the edge position of the first body portion 12 and the edge position of the second body portion 22 are not directly compared, but the relative position between the first body portion 12 and the second body portion 22 (i.e., the gap between the first electrode 10 and the second electrode 20) is indirectly determined based on the relative position of the extension portion 16 and the second body portion 22.

[0117] Therefore, in the present embodiment, even if the uncoated portion 24 provided on the edge of the second body portion 22 covers the edge portion of the first body portion 12, it is possible to appropriately determine whether the electrode assembly 1 is defective.

[0118] Therefore, in the electrode assembly 1 manufactured by the method for manufacturing an electrode assembly according to the embodiment of the present disclosure, the uncoated portion 24 of the second electrode 20 can have a wider width w, thereby maximizing the effect of the uncoated portion 24.

[0119] Referring toFigure 3 and Figure 8 In step S400 of the method for manufacturing an electrode assembly according to the embodiment of the present disclosure, first, information about the relative position between the extension portion 16 of the first electrode 10 and the second electrode 20 is obtained (S410). At this time, step S410 can be performed by a predetermined sensor or detection device, but is not limited thereto.

[0120] In the present embodiment, in step S410, the edge of the extension portion 16 is recognized (S411), and the edge of the second body portion 22 is recognized (S412). The order of step S411 and step S412 is not particularly limited.

[0121] At this time, in step S411, the reference side portion 16a can be recognized as the edge of the extension portion 16. Also, in step S412, the second side portion 22a can be recognized as the edge of the second body portion 22. At this time, the second side portion 22a can be a side portion adjacent to the first side portion 12a of the first body portion 12.

[0122] Also, in step S410 of the method for manufacturing an electrode assembly according to the embodiment of the present disclosure, the distance D between the reference side portion 16a recognized in step S411 and the second side portion 22a recognized in step S412 is measured (S413). Hereinafter, the distance D will be referred to as a reference distance D.

[0123] Referring again to Figure 3 , Figure 8 and Figure 9 In step S400 of the method for manufacturing an electrode assembly according to the embodiment of the present disclosure, information about the reference distance D is obtained as information about the relative position of the extension portion 16 and the second electrode 20 (S410), and the reference distance D obtained in step S410 and the length L1 of the extension portion 16 extending from the first side portion 12a of the first body portion 12 are compared with each other (S420).

[0124] At this time, in step S420 of the method for manufacturing an electrode assembly according to the embodiment of the present disclosure, it can be determined whether the length L1 of the extension portion 16 extending from the first side portion 12a of the first body portion 12 is greater than the reference distance D.

[0125] Also, in step S400 of the method for manufacturing an electrode assembly according to the embodiment of the present disclosure, the length L1 of the extension portion 16 and the reference distance D are compared with each other (S420), and it is determined whether the electrode assembly 1 is defective based on the comparison result (S430, S440).

[0126] At this time, in step S430 and step S440, in order to determine whether the formed electrode assembly 1 is defective, it can be determined whether the second body portion 22 protrudes outside the edge of the first body portion 12 based on the comparison result of step S420.

[0127] More specifically, in step S400 according to the present embodiment, if the reference distance D' is less than the length L1 of the extension portion 16 as shown in Figure 9 , it is determined that the electrode assembly 1' is defective (S430). This is because the comparison result indicates that at least a part of the second body portion 22 is located outside the edge of the first body portion 12.

[0128] Alternatively, in step S400 according to the present embodiment, if the reference distance D is greater than the length L1 of the extension portion 16 as shown in Figure 3 , it is determined that the electrode assembly 1 is not defective (S440). This is because the comparison result indicates that the second body portion 22 is located inside the edge of the first body portion 12.

[0129] Whether the electrode assembly is defective can be determined by the above-described step S400. If it is determined that the electrode assembly is defective, the electrode assembly can be discarded. Alternatively, the electrode assembly can be separated into the first electrode, the second electrode, and the separator, and then stacked again.

[0130] In this way, according to the method for manufacturing an electrode assembly according to the embodiments of the present disclosure, even if the edge portion of the first body portion is covered by the uncoated portion of the second electrode, the gap between the first electrode and the second electrode can be indirectly measured based on information about the relative position between the extension portion and the second electrode. Therefore, in the electrode assembly manufactured by the manufacturing method, the uncoated portion of the second electrode can be formed in a wider area, thereby further improving its effect.

[0131] Meanwhile, in step S400 of the method for manufacturing an electrode assembly according to the embodiments of the present disclosure, the reference distance D between the reference side portion 16a and the first side portion 12a is obtained as information about the relative position between the extension portion 16 and the second electrode 20, and the length L1 of the extension portion 16 and the reference distance D are compared with each other. However, step S400 of the method for manufacturing an electrode assembly according to the present embodiment is only an example of a method for determining whether an electrode assembly is defective based on information about the relative position between the extension portion 16 and the second electrode 20, and step S400 can be appropriately modified as needed.

[0132] The present disclosure has been described above with respect to a limited number of embodiments and drawings, but the present disclosure is not limited thereto, and the present disclosure can be implemented in different forms by those of ordinary skill in the technical field to which the present disclosure pertains within the scope of the technical aspects of the present disclosure and the appended claims and equivalents thereof.

[0133] [LIST OF REFERENCE NUMERALS]

[0134] 1: electrode assembly

[0135] 10, 110, 210: first electrode

[0136] 12: first body portion

[0137] 14: first tab portion

[0138] 16, 116, 216: extension portion

[0139] 20: second electrode

[0140] 22: second body portion

[0141] 24: uncoated portion

[0142] 26: second tab portion

[0143] 30: separator

Claims

1. An electrode assembly comprising: a first electrode including a first body portion coated with a first electrode active material and a first tab portion extending outward from an edge of the first body portion; a second electrode including a second body portion stacked on one surface of the first body portion and coated with a second electrode active material, and an uncoated portion provided on an edge of the second body portion and overlapping the edge of the first body portion; and a separator interposed between the first electrode and the second electrode, wherein the first electrode further includes an extension portion provided on the edge of the first body portion and protruding outward with respect to the uncoated portion. 2.The electrode assembly of claim 1, wherein the edge of the first body portion and the uncoated portion extend in parallel to each other. wherein 3.The electrode assembly of claim 2, wherein the edge of the uncoated portion forms a predetermined interval in a width direction from the edge of the first body portion. wherein 4.The electrode assembly of claim 3, wherein the edge of the uncoated portion is positioned further outward than the edge of the first body portion. wherein 5.The electrode assembly of claim 1, wherein the extension portion extends from the first body portion by a length shorter than a length by which the first tab portion extends from the first body portion. wherein 6.The electrode assembly of claim 1, wherein the first tab portion and the extension portion are provided to be spaced apart at a predetermined interval along the edge of the first body portion. wherein 7.The electrode assembly of claim 1, wherein the second electrode includes a second tab portion provided on the edge of the second body portion, and wherein wherein the second tab portion and the extension portion are spaced apart from each other so as not to overlap in a stacking direction of the first body portion and the second body portion. 8.The electrode assembly of claim 1, wherein the first tab portion extends from one side of the first body portion, and wherein, wherein the extension portion extends from the other side of the first body portion. 9.The electrode assembly of claim 8, wherein the first tab portion and the extension portion are staggered with respect to a length direction of the first body portion. wherein 10.The electrode assembly of claim 1, wherein the extension portion has a film or sheet shape extending in parallel to the first body portion. wherein, 11.The electrode assembly of claim 10, wherein the extension portion includes a first side portion parallel to the edge of the second body portion. wherein 12.The electrode assembly of claim 11, wherein the extension portion further includes a second side portion connecting the first side portion and the first body portion and being perpendicular or inclined with respect to the first side portion. wherein 13.The electrode assembly of claim 1, wherein the second electrode includes a protective layer provided on an outer surface of the uncoated portion. wherein, 14.A method for manufacturing an electrode assembly, comprising: ​ a step of providing a first electrode including a first body portion in the shape of a film or sheet to which a first electrode active material is applied, and a first tab portion and an extension portion extending from an edge of the first body portion; a step of providing a second electrode in which a second electrode active material is applied to at least one region; a step of forming an electrode assembly by stacking the first electrode and the second electrode with a separator interposed therebetween; and a step of determining whether the electrode assembly is defective based on information about a relative position of the extension portion projecting outward with respect to the second electrode and the second electrode.

15. The method for manufacturing an electrode assembly according to claim 14, wherein in the step of providing the second electrode, a second electrode including a second body portion in the shape of a film or sheet coated with a second electrode active material and an uncoated portion provided on an edge of the second body portion is provided, and the step of determining whether the electrode assembly is defective includes a step of obtaining information about a relative position between the extension portion and the second body portion.

16. The method for manufacturing an electrode assembly according to claim 15, wherein the step of obtaining information about a relative position between the extension portion and the second body portion includes: a step of identifying an edge of an end portion side of the extension portion in an extension direction; a step of identifying the edge of the second body portion; and a step of measuring a reference distance that is a distance between the edge of the extension portion and the edge of the second body portion.

17. The method for manufacturing an electrode assembly according to claim 16, wherein the step of determining whether the electrode assembly is defective includes: a step of comparing the reference distance with a length of the extension portion extending from the first body portion; and a step of determining whether the second body portion protrudes to an outside of an edge of the first body portion based on a result of the comparison.

18. The method for manufacturing an electrode assembly according to claim 17, wherein, in the step of determining whether the second body portion protrudes, if the reference distance is greater than the length of the extension portion, it is determined that the second body portion does not protrude to an outside of the first body portion.

19. The method for manufacturing an electrode assembly according to claim 14, wherein, in the step of providing the second electrode, a second electrode including a second body portion in the shape of a film or sheet coated with a second electrode active material and a second tab portion extending from an edge of the second body portion is provided, and in the step of stacking the first electrode and the second electrode, the second tab portion and the extension portion are disposed so as not to overlap in a direction in which the first electrode and the second electrode are stacked.

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