Electrode assembly, method for manufacturing the same, and battery cell containing the same

Abstract

According to one embodiment of the present invention, there is provided an electrode assembly in which electrodes and first separator sheets are alternately stacked, the electrodes including a first electrode and a second electrode, the first separator sheet having a zigzag shape formed by folding at least two times, the second electrode having a length shorter than that of the first electrode, and a molding member positioned between the first separator sheet enclosing the second electrode and an outer surface of the electrode assembly and between the second electrode and the outer surface of the electrode assembly.

Description

Technical Field

[0001] Cross - reference to related applications This application claims the benefit of priority based on Korean Patent Application No. 10 - 2022 - 0057202 filed on May 10, 2022 and Korean Patent Application No. 10 - 2023 - 0054961 filed on April 26, 2023, and all the contents disclosed in the documents of the Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to an electrode assembly, a method for manufacturing the same, and a battery cell including the same. More specifically, the present invention relates to an electrode assembly in which an electrode and a separator sheet are alternately laminated in a Z - folding type, and a battery cell including the same, and an electrode assembly, a method for manufacturing the same, and a battery cell including the same, which can prevent the occurrence of overhang where the positive electrode deviates from the negative electrode and the alignment is disturbed.

Background Art

[0003] Generally, types of secondary batteries include nickel - cadmium batteries, nickel - metal hydride batteries, lithium - ion batteries, and lithium - ion polymer batteries. Such secondary batteries are not only used in small products such as digital cameras, P - DVDs, MP3Ps, mobile phones, PDAs (registered trademark), Portable Game Devices, Power Tools, and E - bikes, but also in large products that require high power such as electric vehicles and hybrid vehicles, and power storage devices for storing surplus generated power and new renewable energy, and backup power storage devices.

[0004] To manufacture such secondary batteries, first, an electrode active material slurry is applied to a positive electrode current collector and a negative electrode current collector to manufacture a positive electrode and a negative electrode, and a predetermined - shaped electrode assembly is formed by laminating them on both sides of a separator. Then, the electrode assembly is housed in a battery case and sealed after injecting an electrolyte.

[0005] Electrode assemblies are classified into various types. For example, there is the simple stack type, which simply stacks positive electrodes, separator membranes, and negative electrodes in a cross pattern without manufacturing unit cells; the lamination and stack type (L&S), which first manufactures unit cells using positive electrodes, separator membranes, and negative electrodes, and then stacks these unit cells; the stack and folding type (S&F), which attaches multiple unit cells spaced apart to one side of a separator membrane sheet that is longer on one side, and then repeatedly folds the separator membrane sheet from one end in the same direction; and the Z-folding type, which alternately attaches multiple electrodes or unit cells to one side and the other side of a separator membrane sheet that is longer on one side, and then folds the separator membrane sheet from one end in a specific direction, and then folds it in the opposite direction, repeating this process alternately. Of these, the Z-folding type has a high degree of alignment and electrolyte impregnation and is frequently used recently.

[0006] However, conventionally, when electrodes and a separator membrane sheet were stacked in such a Z-folding configuration, the portion of the separator membrane sheet surrounding the electrodes significantly exceeded the negative and positive electrodes, resulting in a design where the positive electrode had a smaller area than the negative electrode. This increased the likelihood of overhang, where the positive electrode deviated from the negative electrode and disrupted alignment. When this overhang occurs, not only does the performance of the electrode assembly and the battery cell containing it deteriorate, but the possibility of defects such as short circuits also becomes very high.

[0007] Therefore, it is necessary to develop an electrode assembly and a battery cell containing the same that have a structure capable of preventing overhang, where the positive electrode deviates from the negative electrode and disrupts the alignment. [Overview of the project] [Problems that the invention aims to solve]

[0008] The problem that the present invention aims to solve is to provide an electrode assembly in which electrodes and separation membrane sheets are alternately stacked in a Z-folding type, a method for manufacturing the same, and a battery cell including the same, which can prevent the occurrence of overhang where the positive electrode deviates from the negative electrode and disrupts the alignment.

[0009] The problems that this invention aims to solve are not limited to those described above, and any problems not mentioned should be clearly understood by a person with ordinary skill in the art to which this invention pertains from this specification and the accompanying drawings. [Means for solving the problem]

[0010] An electrode assembly according to one embodiment of the present invention is an electrode assembly in which electrodes and a first separation membrane sheet are alternately stacked, wherein the electrodes include a first electrode and a second electrode, the first separation membrane sheet has a zigzag shape formed by folding at least twice, the length of the second electrode is shorter than the length of the first electrode, and includes a molded member located between the first separation membrane sheet enclosing the second electrode and the outer surface of the electrode assembly, and between the second electrode and the outer surface of the electrode assembly.

[0011] The molded member can be placed between the first separation membrane sheet enclosing the first electrode and the outer surface of the electrode assembly, and between the first electrode and the outer surface of the electrode assembly.

[0012] The side of the first electrode opposite to the side covered by the first separation membrane sheet may be in contact with the molded member, and the side of the second electrode opposite to the side covered by the first separation membrane sheet may be in contact with the molded member.

[0013] The molded member can completely cover the side of the first electrode opposite to the side that is wrapped by the first separation membrane sheet.

[0014] The side of the first electrode that is covered by the first separation membrane sheet may be in contact with the first separation membrane sheet, and the side of the second electrode that is covered by the first separation membrane sheet may be in contact with the first separation membrane sheet.

[0015] The electrode assembly according to this embodiment includes a first tolerance and a second tolerance, the second tolerance may be even larger than the first tolerance.

[0016] The molded member can satisfy the first tolerance and the second tolerance.

[0017] The area of ​​the molded member that protrudes from one side surface of the electrode assembly where the first tolerance is formed is larger than the area that protrudes from the other side surface of the electrode assembly where the second tolerance is formed.

[0018] The electrode assembly according to this embodiment further includes a second separation membrane sheet, the second separation membrane sheet can enclose the entire outer surface of the electrode assembly and form the outer surface of the electrode assembly.

[0019] A method for manufacturing an electrode assembly according to another embodiment of the present invention includes the steps of: manufacturing an electrode assembly by alternately stacking a first electrode, a second electrode, and a first separation membrane sheet; placing a moldable material on the electrode assembly; and wrapping the outer surface of the electrode assembly with a second separation membrane sheet, wherein the first separation membrane sheet has a zigzag shape formed by folding at least twice, and the step of placing the moldable material on the electrode assembly includes placing the moldable material between the first separation membrane sheet wrapping the second electrode and the outer surface of the electrode assembly, and between the second electrode and the outer surface of the electrode assembly.

[0020] The step of placing the moldable material in the electrode assembly may include placing the moldable material between the first separation membrane sheet enclosing the first electrode and the outer surface of the electrode assembly, and between the first electrode and the outer surface of the electrode assembly.

[0021] According to another embodiment of the present invention, the method for manufacturing an electrode assembly may further include a step of heating and pressurizing the electrode assembly after the step of disposing the moldable material on the electrode assembly.

[0022] Of the two side surfaces of the first electrode, the side surface opposite to the side surface wrapped by the first separation membrane sheet may be in contact with the molding member, and of the two side surfaces of the second electrode, the side surface opposite to the side surface wrapped by the first separation membrane sheet may be in contact with the molding member.

[0023] The electrode assembly includes a first tolerance and a second tolerance, and the second tolerance may be even larger than the first tolerance.

[0024] The molding member can satisfy the first tolerance and the second tolerance.

[0025] A battery cell according to another embodiment of the present invention includes the aforementioned electrode assembly.

Advantages of the Invention

[0026] According to the embodiment, the present invention is of a Z-folding type in which electrodes and separation membrane sheets are alternately laminated, and by including a molding member located between the first separation membrane sheet wrapping the second electrode and the outer surface of the electrode assembly and between the second electrode and the outer surface of the electrode assembly, it is possible to prevent the occurrence of overhang where the positive electrode deviates from the negative electrode and the alignment is disrupted.

[0027] Also, the present invention is of a Z-folding type in which electrodes and separation membrane sheets are alternately laminated, and by including a molding member located between the first separation membrane sheet wrapping the first electrode and the outer surface of the electrode assembly and between the first electrode and the outer surface of the electrode assembly, it is possible to prevent the occurrence of overhang where the positive electrode deviates from the negative electrode and the alignment is disrupted.

[0028] In addition, by including a molding member, the present invention can prevent the occurrence of overhang, prevent deterioration of the performance of the battery cell, minimize the possibility of defects such as short circuits, and improve the performance and stability of the electrode assembly and the battery cell.

[0029] The effects of the present invention are not limited to the above-mentioned effects, and the effects not mentioned should be clearly understood by those with ordinary knowledge in the technical field to which the present invention pertains from this specification and the attached drawings.

Brief Description of the Drawings

[0030] [Figure 1] It is a diagram showing a final electrode assembly according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view of the electrode assembly cut along the cutting line A-A' of FIG. 1. [Figure 3] It is a diagram showing only a part of the components of the electrode assembly of FIG. 2. [Figure 4] It is a diagram showing a state where a molding member is formed on the electrode assembly of FIG. 3. [Figure 5] It is a diagram showing a state of forming the outer surface of the electrode assembly of FIG. 4. [Figure 6] It is a diagram showing a view from above of the plane cut along the cutting line B-B' of FIG. 1. [Figure 7] It is a diagram showing a manufacturing method of an electrode assembly according to another embodiment of the present invention. [Figure 8] It is a diagram showing a manufacturing method of an electrode assembly according to another embodiment of the present invention. [Figure 9] It is a diagram showing a manufacturing method of an electrode assembly according to another embodiment of the present invention.

Modes for Carrying Out the Invention

[0031] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings, so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. The present invention can be realized in a variety of different forms and is not limited to the embodiments described herein.

[0032] To clearly explain the present invention, unnecessary explanatory parts have been omitted, and the same or similar components are given the same reference numerals throughout the specification.

[0033] Furthermore, the dimensions and thicknesses of each component shown in the drawings are arbitrary for the sake of explanation, and therefore the present invention is not necessarily limited to what is shown. In the drawings, the thicknesses are shown enlarged to clearly represent the various layers and regions. Also, in the drawings, the thicknesses of some layers and regions are shown exaggerated for the sake of explanation.

[0034] Furthermore, when a specification states that a certain part "includes" a certain component, unless otherwise stated, this means that it may include other components rather than excluding them.

[0035] Furthermore, throughout the specification, "on a plane" means when the subject is viewed from above, and "on a cross-section" means when the subject is viewed from the side of a cross-section obtained by cutting the subject perpendicularly.

[0036] The following describes an electrode assembly according to an embodiment of the present invention. However, although the description here is based on a partial cross-section of the electrode assembly, it is not necessarily limited to this, and the same or similar content can be used when other cross-sections are used.

[0037] Figure 1 shows a final electrode assembly according to one embodiment of the present invention. Figure 2 is a cross-sectional view of the electrode assembly cut along the cutting line A-A' in Figure 1.

[0038] Referring to Figures 1 and 2, the final electrode assembly 100 according to this embodiment can be said to have a structure in which a fixing tape 300 is attached to the outer surface of the electrode assembly 200. This allows the final electrode assembly 100 to maintain the stacked alignment state between the first electrode 210, the second electrode 220, and the separation membrane sheets 250 and 270 contained in the electrode assembly 200. In particular, the fixing tape 300 can maintain the stacked alignment state between the electrodes 210 and 220 and the separation membrane sheets 250 and 270. However, it is not limited to this, and the fixing tape 300 may be omitted in the final electrode assembly 100 or replaced with other members to maintain the stacked alignment state between the first electrode 210, the second electrode 220, and the separation membrane sheets 250 and 270.

[0039] Furthermore, the final electrode assembly 100 may include electrode leads 400 to which electrode tabs extending from a plurality of first electrodes 210 and a plurality of second electrodes 220 included in the electrode assembly 200 are joined. For example, as shown in Figure 1, the electrode leads 400 may extend from both ends of the electrode assembly 200, and the electrode leads 400 can be classified as positive leads or negative leads depending on the polarity of the first electrodes 210 and the second electrodes 220. However, the position of the electrode leads 400 is not limited to this, and unlike in Figure 1, they may both extend from one end of the electrode assembly 200.

[0040] Furthermore, the final electrode assembly 100 may include lead films 500 located above and below the electrode leads 400. Here, when the final electrode assembly 100 is mounted in a battery case (not shown), the lead films 500 are sealed together with the outer periphery of the battery case (not shown) by a sealing portion (not shown).

[0041] Referring to Figures 1 and 2, the electrode assembly 200 according to one embodiment of the present invention may be an electrode assembly in which electrodes 210, 220 and a first separation membrane sheet 250 are alternately laminated.

[0042] The electrodes 210 and 220 may include a first electrode 210 and a second electrode 220. Here, the first electrode 210 and the second electrode 220 may include electrode active materials having different polarities. That is, the first electrode 210 and the second electrode 220 may be electrodes with different polarities. For example, if the first electrode 210 is a negative electrode, the second electrode 220 may be a positive electrode.

[0043] Furthermore, the length of the second electrode 220 may be shorter than the length of the first electrode 210. In other words, the length of the first electrode 210 may be longer than the length of the second electrode 220. That is, the first electrode 210 and the second electrode 220 may have different lengths, and there may be a difference in length between the first electrode 210 and the second electrode 220.

[0044] Furthermore, the area of ​​the second electrode 220 may be smaller than the area of ​​the first electrode 210. In other words, the area of ​​the first electrode 210 may be larger than the area of ​​the second electrode 220. That is, the first electrode 210 and the second electrode 220 may have different areas, and there may be a difference in size between the first electrode 210 and the second electrode 220.

[0045] The first separation membrane sheet 250 can have a zigzag shape formed by folding at least twice. More specifically, as shown in Figure 2, the separation membrane sheet 250 is folded in a direction that covers the first electrode 210 when the first electrode 210 is stacked on it. Then, with the second electrode 220 stacked on the first separation membrane sheet 250 covering the first electrode 210, it is folded in a direction that covers the second electrode 220. Subsequently, with the first electrode 210 stacked on the first separation membrane sheet 250 covering the second electrode 220, it is folded in a direction that covers the first electrode 210. In other words, the electrode assembly 200 can be formed by repeatedly stacking the first electrode 210 or the second electrode 220 and folding the first separation membrane sheet 250.

[0046] Therefore, the first separation membrane sheet 250 is interposed between the upper surface of the first electrode 210 and the lower surface of the second electrode 220, and between the upper surface of the second electrode 220 and the lower surface of the first electrode 210.

[0047] In addition, as described above, the folding of the separation membrane allows the side of the first electrode 210 opposite to the side wrapped by the first separation membrane sheet 250 and the side of the second electrode 220 wrapped by the first separation membrane sheet 250 to be located adjacent to each other. At the same time, the side of the first electrode 210 wrapped by the first separation membrane sheet 250 and the side of the second electrode 220 opposite to the side wrapped by the first separation membrane sheet 250 can be located adjacent to each other. Therefore, a Z-folding type electrode assembly can be formed.

[0048] Furthermore, the side of the second electrode 220 that is covered by the first separation membrane sheet 250 may be in contact with the first separation membrane sheet 250, and the side of the first electrode 210 that is covered by the separation membrane sheet may be in contact with the first separation membrane sheet 250. Here, the meaning of the side of the first electrode 210 or the second electrode 220 being in contact with the first separation membrane sheet 250 can mean that the first separation membrane sheet 250 extends to the side of the first electrode 210 or the second electrode 220, or that the first separation membrane sheet 250 covers the side of the first electrode 210 or the second electrode 220.

[0049] This makes it possible to more effectively prevent the first electrode 210 and the second electrode 220 from being distorted within the first separation membrane sheet 250 in this embodiment.

[0050] Furthermore, the side of the first electrode 210 opposite to the side enclosed by the separation membrane sheet 250 may protrude from the side of the second electrode 220 that is enclosed by the separation membrane sheet 250 compared to the second electrode 220. At the same time, the side of the first electrode 210 that is enclosed by the separation membrane sheet 250 may protrude from the side of the second electrode 220 that is enclosed by the separation membrane sheet 250 compared to the second electrode 220. In other words, the first electrode 210 can be formed such that at least one side protrudes from the second electrode 220, and specifically, both sides may all protrude. Therefore, using both sides as a reference, it can be said that the second electrode 220 is located inside the first electrode 210.

[0051] The electrode assembly according to one embodiment of the present invention will be described in more detail below with reference to Figures 3 to 6.

[0052] Figure 3 shows only a portion of the components of the electrode assembly in Figure 2. Figure 4 shows the electrode assembly in Figure 3 with the molded members formed. Figure 5 shows the formation of the outer surface of the electrode assembly in Figure 4. Figure 6 shows a top view of the plane cut along the cutting line B-B' in Figure 1.

[0053] In conventional electrode assemblies, when electrodes and separation membrane sheets are stacked alternately, there is a high possibility of overhang occurring, where the positive electrode deviates from the negative electrode in the electrode region not enclosed by the separation membrane sheet, disrupting alignment and causing the positive electrode to protrude outward compared to the negative electrode. When overhang occurs, not only does the performance of the electrode assembly deteriorate, but the possibility of failure due to short circuits increases, making it difficult to ensure the stability of the electrode assembly.

[0054] Therefore, referring to Figure 2, the molded member 290 can be positioned between the first separation membrane sheet 250 surrounding the second electrode 220 and the outer surface of the electrode assembly 200, and between the second electrode 220 and the outer surface of the electrode assembly 200. The molded member 290 can also be positioned between the first separation membrane sheet 250 surrounding the first electrode 210 and the outer surface of the electrode assembly 200, and between the first electrode 210 and the outer surface of the electrode assembly 200. More specifically, the molded member 290 can be formed between the first separation membrane sheet 250 in contact with the upper surface of the second electrode 220 and the first separation membrane sheet 250 in contact with the lower surface of the second electrode 220. The molded member 290 can also be formed between the upper surface of the first electrode 210 that does not contact the first separation membrane sheet 250 and the lower surface of the first electrode 210 that does not contact the first separation membrane sheet 250.

[0055] As a result, in this embodiment, the molded member 290 is positioned in the space formed between the first separation membrane sheet 250 surrounding the second electrode 220 and the outer surface of the electrode assembly 200, and between the second electrode 220 and the outer surface of the electrode assembly 200, thereby preventing the overhang phenomenon in which the second electrode 220 deviates from the first electrode 210 and disrupts alignment.

[0056] On the other hand, the side of the first electrode 210 opposite to the side covered by the first separation membrane sheet 250 may be in contact with the molding member 290. More specifically, the molding member 290 can completely cover the side of the first electrode 210 opposite to the side covered by the first separation membrane sheet 250.

[0057] Furthermore, the side of the second electrode 220 opposite to the side covered by the first separation membrane sheet 250 may be in contact with the molding member 290. More specifically, the molding member 290 can completely cover the side of the second electrode 220 opposite to the side covered by the first separation membrane sheet 250.

[0058] Therefore, the areas of the first electrode 210 and the second electrode 220 that are not covered by the first separation membrane sheet 250 are covered and fixed by the molding member 290, thereby restricting the movement of the first electrode 210 and the second electrode 220 and preventing the occurrence of overhang.

[0059] Furthermore, referring to Figure 3, the electrode assembly 200 according to this embodiment may include a first tolerance G1, which may be the distance G1 at which the side opposite to the side of the first electrode 210 that is covered by the first separation membrane sheet 250 protrudes from the first separation membrane sheet 250 that covers the second electrode 220.

[0060] Furthermore, the electrode assembly 200 according to this embodiment may include a second tolerance G2, which may be the distance G2 by which the first separation membrane sheet 250 surrounding the first electrode 210 protrudes from the side of the second electrode 220 opposite to the side covered by the first separation membrane sheet 250.

[0061] In this case, the second tolerance G2 may be greater than the first tolerance G1. In other words, the first tolerance G1 may be less than the second tolerance G2. That is, the space between the upper surface of the first electrode 210 that does not contact the first separation membrane sheet 250 and the lower surface of the first electrode 210 that does not contact the first separation membrane sheet 250 can have a smaller area than the space between the first separation membrane sheet 250 that contacts the upper surface of the second electrode 220 and the first separation membrane sheet 250 that contacts the lower surface of the second electrode 220.

[0062] On the other hand, the molded member 290 can satisfy the first tolerance G1 and the second tolerance G2. In this case, since the second tolerance G2 is greater than the first tolerance G1, the area of ​​the molded member 290 that satisfies the second tolerance G2 may be larger than the area of ​​the molded member 290 that satisfies the first tolerance G1.

[0063] As a result, the sides of the second electrode 220 that are not covered by the first separation membrane sheet 250 can be fixed with greater strength. Therefore, the movement of the second electrode 220 is prevented by the molded member 290 that is filled with the second tolerance G2, and the second electrode 220 is fixed within the electrode assembly 200, thereby preventing overhang and improving the stability of the electrode assembly 200.

[0064] Furthermore, referring to Figure 4, the area of ​​the molded member 290 that protrudes from one side surface of the electrode assembly 200 on which the first tolerance G1 is formed may be larger than the area that protrudes from the other side surface of the electrode assembly 200 on which the second tolerance G2 is formed. In this case, the one side surface of the electrode assembly 200 on which the first tolerance G1 is formed may represent a virtual vertical line formed by connecting the opposite sides of each first electrode 210 formed on the electrode assembly 200 that are wrapped by the first separation membrane sheet 250. Also, the other side surface of the electrode assembly 200 on which the second tolerance G2 is formed may represent a virtual vertical line formed by connecting the sides of the first separation membrane sheet 250 that wrap each first electrode 210.

[0065] When the first tolerance G1 and the second tolerance G2 are satisfied, a portion of the molded member 290 remaining after satisfying the first tolerance G1 and the second tolerance G2 may extend beyond both sides of the electrode assembly 200. In this case, since the second tolerance G2 is greater than the first tolerance G1, when molded member 290 of the same area is made to satisfy the first tolerance G1 and the second tolerance G2, the area extending beyond one side of the electrode assembly 200 where the first tolerance G1 is formed may be even larger than the area extending beyond the other side of the electrode assembly 200 where the second tolerance G2 is formed.

[0066] As a result, the movement of the first electrode 210, which is not enclosed by the first separation membrane sheet 250, is prevented by the molding member 290 formed beyond one side surface of the electrode assembly 200 on which the first tolerance G1 is formed, thereby preventing overhang due to movement of the first electrode 210. In particular, since the first electrode 210 is formed with a longer length or a larger area than the second electrode 220, the movement of the first electrode 210 can be effectively suppressed by forming a larger area of ​​the molding member 290 that extends beyond one side surface of the electrode assembly 200 on which the first tolerance G1 is formed.

[0067] On the other hand, referring to Figure 5, the electrode assembly 200 according to this embodiment further includes a second separation membrane sheet 270, and the second separation membrane sheet 270 can wrap around the entire outer surface of the electrode assembly 200 and form the outer surface of the electrode assembly 200.

[0068] In this case, the second separation membrane sheet 270 can be formed integrally with the first separation membrane sheet 250, and therefore, the second separation membrane sheet 270 may be an extension of one end of the first separation membrane sheet 250.

[0069] As a result, in this embodiment, the electrode assembly 200 has the second separation membrane sheet 270 covering the outer surface of the electrode assembly 200, preventing the first electrode 210 and the second electrode 220 from protruding outwards or overhanging, and allowing the molded member 290 to be stably fixed.

[0070] On the other hand, referring to Figure 6, the electrode assembly 200 according to this embodiment can include a plurality of molded members 290. Figure 6 shows the electrode assembly 200 of Figure 1 as viewed from above after being cut along the cutting line B-B', and the molded members 290 can be formed to cover each side of the second electrode 220 so that the second electrode 220 is fixed in place.

[0071] This prevents the overhang phenomenon in which the second electrode 220 deviates from the first electrode 210 and disrupts alignment, and the position of the second electrode 220 is fixed by the molding member 290, thereby improving the stability of the electrode assembly 200.

[0072] Furthermore, in this embodiment, the electrode assembly 200 includes a molded member 290, which prevents the overhang phenomenon in which the second electrode 220 deviates from the first electrode 210 and disrupts alignment. The molded member 290 may be formed by placing a moldable material on the electrode assembly 200. In particular, since the molded member 290 is made of a moldable material, it can be deformed to match the shape of the electrode assembly 200 and formed to make close contact with the first electrode 210 and the second electrode 220, thereby maximizing the effect of preventing movement of the first electrode 210 and the second electrode 220 and preventing overhang.

[0073] Here, the moldable material used to form the molded member 290 according to this embodiment may be a material that can be molded at a temperature of 120 degrees Celsius or lower. This prevents shrinkage of the first separation membrane sheet 250 and the second separation membrane sheet 270 contained in the electrode assembly 200 during the process in which the moldable material forms the molded member 290.

[0074] Furthermore, the moldable material used to form the molded member 290 according to this embodiment may be a material that can be molded at temperatures of 50 degrees Celsius or higher. This ensures that the molded member 290 does not deform within the temperature range in which the electrode assembly 200 is used after the process of forming the molded member 290.

[0075] In contrast, if the moldable material is a material that can be molded at temperatures exceeding 120 degrees Celsius, there is a problem that shrinkage of the first separation membrane sheet 250 and the second separation membrane sheet 270 occurs during the process of forming the molded member 290. Also, if the moldable material is a material that can be molded at temperatures below 50 degrees Celsius, there is a problem that the molded member 290 deforms within the temperature range in which the electrode assembly 200 is used, and the molded member 290 does not come into close contact with the first electrode 210 and the second electrode 220.

[0076] Furthermore, the moldable material used to form the molded member 290 according to this embodiment may be a material that can be molded under pressure such that it deforms to match the shape of the electrode assembly 200. This allows the moldable material to be easily deformed to match the shape of the electrode assembly 200, and the molded member 290 to be easily formed.

[0077] As an example, the moldable material used to form the molded member 290 according to this embodiment may be a polymer material, and specifically, it can be formed from one or more materials selected from the group including olefins, acrylates, urethanes, esters, amides, vinyl acetates, and rubbers. However, it is not limited to this, and any material that can be deformed to match the shape of the electrode assembly 200 and formed to make close contact with the first electrode 210 and the second electrode 220, thereby preventing overhang, is included in this embodiment.

[0078] As a result, in this embodiment, the movement of the first electrode 210 and the second electrode 220 is restricted by the molding member 290, preventing the overhang phenomenon in which the second electrode 220 deviates from the first electrode 210 and disrupts alignment, thereby improving the stability of the electrode assembly. In particular, the molding member 290 is inserted into the electrode assembly 200 so as to deform to match the shape of the electrode assembly 200 and form a close contact with the first electrode 210 and the second electrode 220, thereby stably fixing the positions of the first electrode 210 and the second electrode 220.

[0079] The following describes a method for manufacturing an electrode assembly according to another embodiment of the present invention, with reference to Figures 7 to 9. In this case, all the details regarding the electrode assembly described above are included in this embodiment, and only the differences will be described.

[0080] Figures 7 to 9 illustrate a method for manufacturing an electrode assembly according to another embodiment of the present invention.

[0081] Referring to Figures 7 and 8, the method for manufacturing an electrode assembly according to this embodiment includes the steps of: manufacturing an electrode assembly 200 by alternately stacking a first electrode 210, a second electrode 220, and a first separation membrane sheet 250; placing a moldable material on the electrode assembly 200; and wrapping the outer surface of the electrode assembly 200 with a second separation membrane sheet 270.

[0082] At this time, the step of placing the moldable material on the electrode assembly 200 may include placing the moldable material between the first separation membrane sheet 250 surrounding the second electrode 220 and the outer surface of the electrode assembly 200, and between the second electrode 220 and the outer surface of the electrode assembly 200.

[0083] Furthermore, the step of placing a moldable material on the electrode assembly 200 may include placing the moldable material between the first separation membrane sheet 250 enclosing the first electrode 210 and the outer surface of the electrode assembly 200, and between the first electrode 210 and the outer surface of the electrode assembly 200.

[0084] In particular, referring to Figure 8, the method for manufacturing the electrode assembly according to this embodiment may involve, in the step of wrapping the outer surface of the electrode assembly 200 with the second separation membrane sheet 270, the tension generated by the second separation membrane sheet 270 causing the moldable material to be inserted into the electrode assembly 200 and form the molded member 290.

[0085] The second separation membrane sheet 270 can wrap around the outer surface of the electrode assembly 200 and form the outer surface of the electrode assembly 200, and the tension of the second separation membrane sheet 270 causes the moldable material to deform to match the shape of the electrode assembly 200, so that it can be formed to make close contact with the first electrode 210 and the second electrode 220.

[0086] Referring to Figures 7 and 9, another embodiment of the present invention may further include a step of heating and pressurizing the electrode assembly 200 after the step of placing the moldable material on the electrode assembly 200. In other words, the method for manufacturing the electrode assembly according to this embodiment may further include a step of heating and pressurizing the electrode assembly 200 before the step of wrapping the outer surface of the electrode assembly 200 with the second separation membrane sheet 270. Through the step of heating and pressurizing the electrode assembly 200, the moldable material may be inserted into the electrode assembly 200 to form the molded member 290.

[0087] In particular, by heating each side of the electrode assembly 200 on which the moldable material is placed after it has been placed on the electrode assembly 200, the ability of the moldable material to deform to match the shape of the electrode assembly 200 can be maximized.

[0088] Furthermore, by applying pressure to each side of the electrode assembly 200 on which the moldable material is placed, the area in which the moldable material is inserted into the electrode assembly 200 and contacts the first electrode 210 and the second electrode 220 can be maximized.

[0089] Therefore, the step of heating and pressurizing the electrode assembly 200 can include both heating followed by pressurization and pressurization followed by heating, and simultaneous heating and pressurization is also included in this embodiment.

[0090] Furthermore, the manufacturing method of the electrode assembly according to this embodiment can further enhance the fixing effect of the molded member 290 on the electrode assembly 200 by stably forming the molded member 290 not only through tension from the second separation membrane sheet 270 but also through heating and pressurizing steps.

[0091] On the other hand, the electrode assembly 200 formed by the electrode assembly manufacturing method according to this embodiment can include all of the components of the electrode assembly 200 described above.

[0092] That is, the electrode assembly 200 according to this embodiment may include a first tolerance G1, and the first tolerance G1 may be the distance G1 at which the side opposite to the side of the first electrode 210 that is covered by the first separation membrane sheet 250 protrudes from the first separation membrane sheet 250 that covers the second electrode 220.

[0093] Furthermore, the electrode assembly 200 according to this embodiment may include a second tolerance G2, which may be the distance G2 by which the first separation membrane sheet 250 surrounding the first electrode 210 protrudes from the side of the second electrode 220 opposite to the side covered by the first separation membrane sheet 250.

[0094] In this case, the second tolerance G2 may be greater than the first tolerance G1. In other words, the first tolerance G1 may be less than the second tolerance G2. That is, the space between the upper surface of the first electrode 210 that does not contact the first separation membrane sheet 250 and the lower surface of the first electrode 210 that does not contact the first separation membrane sheet 250 can have a smaller area than the space between the first separation membrane sheet 250 that contacts the upper surface of the second electrode 220 and the first separation membrane sheet 250 that contacts the lower surface of the second electrode 220.

[0095] On the other hand, the molded member 290 formed by the electrode assembly manufacturing method according to this embodiment can satisfy the first tolerance G1 and the second tolerance G2. In this case, since the second tolerance G2 is greater than the first tolerance G1, the area of ​​the molded member 290 that satisfies the second tolerance G2 may be larger than the area of ​​the molded member 290 that satisfies the first tolerance G1.

[0096] As a result, the sides of the second electrode 220 that are not covered by the first separation membrane sheet 250 can be fixed with greater strength. Therefore, the movement of the second electrode 220 is prevented by the molded member 290 that is filled with the second tolerance G2, and the second electrode 220 is fixed within the electrode assembly 200, thereby preventing overhang and improving the stability of the electrode assembly 200.

[0097] As a result, the electrode assembly manufacturing method according to this embodiment is a method for manufacturing an electrode assembly in which a molded member 290 is formed on the electrode assembly 200, and the movement of the first electrode 210 and the second electrode 220 is restricted by the molded member 290, thereby preventing the overhang phenomenon in which the second electrode 220 deviates from the first electrode 210 and disrupts the alignment, and improving the stability of the electrode assembly formed by the electrode assembly manufacturing method according to this embodiment. In particular, the molded member 290 is inserted into the electrode assembly 200 so as to deform to match the shape of the electrode assembly 200 and be tightly formed with the first electrode 210 and the second electrode 220, thereby stably fixing the positions of the first electrode 210 and the second electrode 220.

[0098] A battery cell according to yet another embodiment of the present invention includes the aforementioned electrode assembly. The battery cell may include a battery case (not shown) that houses the aforementioned electrode assembly 200 together with an electrolyte. In this case, the electrode assembly 200 is manufactured from the aforementioned final electrode assembly 100 and housed in the battery case (not shown).

[0099] Here, the battery case (not shown) may be a laminate sheet including a resin layer and a metal layer. More specifically, the battery case (not shown) is made of a laminate sheet and can consist of an outer resin layer forming the outermost corner, a barrier metal layer to prevent penetration of materials, and an inner resin layer for sealing.

[0100] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto. Various modifications and improvements by those skilled in the art, using the basic concepts of the present invention as defined in the following claims, also fall within the scope of the present invention. [Explanation of Symbols]

[0101] 100: Final electrode assembly 200: Electrode assembly 210: 1st electrode 220: 2nd electrode 250: First separation membrane sheet 270: Second separation membrane sheet 290: Molded component 300: Fixing tape 400: Electrode Lead 500: Lead film

Claims

1. An electrode assembly in which electrodes and a first separation membrane sheet are alternately stacked, The electrode includes a first electrode and a second electrode. The first separation membrane sheet has a zigzag shape formed by folding at least twice, The length of the second electrode is shorter than the length of the first electrode. The material includes a molded member located between the first separation membrane sheet enclosing the second electrode and the outer surface of the electrode assembly, and between the second electrode and the outer surface of the electrode assembly, The aforementioned molded member is Located between the first separation membrane sheet enclosing the first electrode and the outer surface of the electrode assembly, and between the first electrode and the outer surface of the electrode assembly, Of the two sides of the first electrode, the side opposite to the side covered by the first separation membrane sheet is in contact with the molded member. An electrode assembly wherein the side of the second electrode opposite to the side covered by the first separation membrane sheet is in contact with the molded member.

2. The electrode assembly according to claim 1, wherein the molded member covers the entire side of the first electrode opposite to the side covered by the first separation membrane sheet.

3. Of the two sides of the first electrode, the side covered by the first separation membrane sheet is in contact with the first separation membrane sheet. The electrode assembly according to claim 1, wherein one of the two sides of the second electrode is enclosed by the first separation membrane sheet and is in contact with the first separation membrane sheet.

4. The first tolerance is the distance that the side opposite to the side of the first electrode that is covered by the first separation membrane sheet protrudes from the first separation membrane sheet that covers the second electrode, and the second tolerance is the distance that the first separation membrane sheet that covers the first electrode protrudes from the side of the second electrode that is opposite to the side of the second electrode that is covered by the first separation membrane sheet. The electrode assembly according to claim 1, wherein the second tolerance is greater than the first tolerance.

5. The aforementioned molded member is The electrode assembly according to claim 4, satisfying the first tolerance and the second tolerance.

6. The aforementioned molded member is The electrode assembly according to claim 5, wherein the area protruding from one side surface of the electrode assembly on which the first tolerance is formed is greater than the area protruding from the other side surface of the electrode assembly on which the second tolerance is formed.

7. Further comprising a second separation membrane sheet, The electrode assembly according to claim 1, wherein the second separation membrane sheet encloses the entire outer surface of the electrode assembly and forms the outer surface of the electrode assembly.

8. A step of manufacturing an electrode assembly by alternately stacking a first electrode, a second electrode, and a first separation membrane sheet; The step of placing a moldable material in the electrode assembly; and The process includes the step of wrapping the outer surface of the electrode assembly with a second separation membrane sheet, The first separation membrane sheet has a zigzag shape formed by folding at least twice, The step of placing the moldable material in the electrode assembly includes placing the moldable material between the first separation membrane sheet enclosing the second electrode and the outer surface of the electrode assembly, and between the second electrode and the outer surface of the electrode assembly. The step of placing the moldable material in the electrode assembly includes placing the moldable material between the first separation membrane sheet enclosing the first electrode and the outer surface of the electrode assembly, and between the first electrode and the outer surface of the electrode assembly. Of the two sides of the first electrode, the side opposite to the side covered by the first separation membrane sheet is in contact with the moldable material. A method for manufacturing an electrode assembly wherein the side of the second electrode opposite to the side covered by the first separation membrane sheet is in contact with the moldable material.

9. The method for manufacturing an electrode assembly according to claim 8, further comprising the step of heating and pressurizing the electrode assembly after the step of placing the moldable material on the electrode assembly.

10. The electrode assembly includes a first tolerance, which is the distance that the side of the first electrode opposite to the side covered by the first separation membrane sheet protrudes from the first separation membrane sheet covering the second electrode, and a second tolerance, which is the distance that the first separation membrane sheet covering the first electrode protrudes from the side of the second electrode opposite to the side covered by the first separation membrane sheet. The electrode assembly manufacturing method according to claim 8, wherein the second tolerance is even greater than the first tolerance.

11. The aforementioned moldable material is A method for manufacturing an electrode assembly according to claim 10, which satisfies the first tolerance and the second tolerance.

12. A battery cell comprising an electrode assembly according to any one of claims 1 to 7.

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