Electrode assembly, method for manufacturing the same, and rechargeable battery

Abstract

One problem that the present invention aims to solve is to provide an electrode assembly, a method for manufacturing an electrode assembly, and a battery including an electrode assembly, which can prevent the reformed separation membrane, after the winding process, from separating from the inner surface of the electrode assembly and crossing the winding core in a cylindrical electrode assembly. [Solution] A cylindrical battery, an electrode assembly contained therein, and a method for manufacturing the same are disclosed. An electrode assembly according to one embodiment is a cylindrical electrode assembly formed by winding a laminate in which a separation membrane is interposed between a positive electrode and a negative electrode multiple times so as to have a winding center, and includes a fixing tape for fixing the separation membrane exposed at the winding center to the inner surface of the electrode assembly.

Description

[Technical Field]

[0001] This disclosure relates to an electrode assembly and a battery including an electrode assembly. [Background technology]

[0002] This application claims priority to Korean Patent Application No. 10-2024-0187806, filed with the Korean Intellectual Property Office on 17 December 2024, the entire contents of which are incorporated herein by reference.

[0003] Unlike primary batteries, which cannot be recharged, secondary batteries are batteries that can be charged and discharged. Low-capacity secondary batteries are used in portable, small electronic devices such as smartphones, feature phones, laptops, digital cameras, and video cameras, while high-capacity secondary batteries are widely used in motor drive power supplies and power storage batteries for hybrid and electric vehicles. Such secondary batteries include electrodes, including a positive and / or negative electrode, an electrode assembly containing the electrodes, a case housing the assembly, and electrode terminals connected to the electrode assembly.

[0004] As technology advances, there is a growing demand for batteries with higher capacities. Consequently, multiple batteries can be electrically connected and used in conjunction with each other. For example, batteries can be applied to electronic devices in the form of battery modules containing multiple batteries and / or battery packs containing multiple battery modules. In one embodiment, multiple batteries may even constitute a battery pack. In this case, the electronic device is one that requires high power and / or high capacity, including, for example, electric vehicles.

[0005] A battery includes electrode assemblies that function as unit structures for performing the charging and discharging of power. Electrode assemblies can be classified into cylindrical, stacked, or stack-and-folding types based on their structure. Among these, cylindrical electrode assemblies have the advantages of relatively large capacity and structural stability.

[0006] Cylindrical electrode assemblies can be manufactured by winding a long, sheet-like laminate of positive electrode / separator / negative electrode / separator multiple times to form a jelly roll. During the winding process, a portion of the separator is grasped, and the laminate is wound multiple times in a clockwise or counterclockwise direction. Once winding the laminate is complete, the grasped separator is released, at which point a portion of the separator takes on the shape of a Taiji pattern crossing the winding core. Since the separator crossing the winding core can be an obstacle in subsequent welding processes, a reform process is performed to make the separator crossing the winding core adhere tightly to the inner surface of the electrode assembly.

[0007] The aforementioned information disclosed in the technology underlying such inventions is merely for the purpose of improving understanding of the background of the present invention, and therefore may include information that does not constitute prior art. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Korean Published Patent Publication No. 10-2023-0098048 [Overview of the project] [Problems that the invention aims to solve]

[0009] One problem that the present invention aims to solve is to provide an electrode assembly, a method for manufacturing an electrode assembly, and a battery including an electrode assembly, which can prevent the reformed separation membrane, after the winding process, from separating from the inner surface of the electrode assembly and crossing the winding core in a cylindrical electrode assembly.

[0010] However, the technical problems that the present invention aims to solve are not limited to those described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention below. [Means for solving the problem]

[0011] One embodiment of the present disclosure for solving the aforementioned technical problems is a cylindrical electrode assembly formed by winding a laminate having a separation membrane interposed between a positive electrode and a negative electrode multiple times so as to have a winding center, and includes a fixing tape for fixing the separation membrane exposed at the winding center to the inner surface of the electrode assembly.

[0012] According to one aspect of the above embodiment, the fixing tape may include an electrically insulating film. The electrically insulating film may be formed from a polyimide (PI) resin, a polyethylene (PE) resin, or a polyester (PET) resin.

[0013] In another aspect of the above embodiment, the fixing tape may include a porous film. The porous film may have a plurality of holes formed in a base film, where the area occupied by the plurality of holes relative to the base film may be 10 to 90%. The plurality of holes may be of uniform size and regularly arranged across the entire surface of the base film, or they may not be of uniform size or irregularly arranged across the entire surface of the base film. The planar shape of the plurality of holes may be circular, elliptical, or polygonal.

[0014] According to yet another aspect of the above embodiment, the fixing tape may include an upper fixing tape and a lower fixing tape attached to the upper and lower sides of the separation membrane, respectively, so as to intersect with the ends of the separation membrane. The fixing tape may further include one or more intermediate fixing tapes attached between the upper fixing tape and the lower fixing tape.

[0015] According to yet another aspect of the above embodiment, the fixing tape may be attached along the edge of the separation membrane.

[0016] Another embodiment of the present disclosure for solving the above technical problem relates to a method for manufacturing an electrode assembly, including the steps of preparing a laminate in which a separator is interposed between a positive electrode and a negative electrode; grasping one end of the separator and winding the laminate multiple times to form a cylindrical electrode assembly; adhering the separator exposed at the winding center of the electrode assembly to the inner surface of the electrode assembly; and inserting a fixing tape into the winding center and fixing the separator adhered to the inner surface of the electrode assembly with the fixing tape.

[0017] According to one aspect of the embodiment, the fixing tape may include an electrically insulating film.

[0018] According to another aspect of the embodiment, the fixing tape may include a porous film. At this time, the porous film has a plurality of holes formed in a base film, and the area occupied by the plurality of holes with respect to the base film may be 10 to 90%.

[0019] According to still another aspect of the embodiment, the fixing tape may be grasped by a jig having a tweezer structure or adsorbed by a jig having an adsorption function and inserted into the winding center.

[0020] Still another embodiment of the present disclosure for achieving the above technical problem relates to a battery, including a cylindrical case and a cylindrical electrode assembly formed by winding a laminate in which a separator is interposed between a positive electrode and a negative electrode and housed inside the cylindrical case. The electrode assembly may include a fixing tape for fixing a separator exposed at the winding center of the electrode assembly to the inner surface of the electrode assembly.

[0021] According to one aspect of the embodiment, the fixing tape may include an electrically insulating and porous film. At this time, the porous film has a plurality of holes formed in a base film, and the area occupied by the plurality of holes with respect to the base film may be 10 to 90%.

[0022] According to an embodiment of the present invention, by using a fixing tape to fix the separation membrane of the core part to the inner surface of the cylindrical electrode assembly, it is possible to prevent the separation membrane from crossing the core part and becoming an obstacle in subsequent processes. And by fixing the separation membrane using a porous fixing tape, it is possible to suppress the decrease in the impregnation property of the electrode assembly due to the fixing tape. In particular, by partially attaching the end portion of the separation membrane with a porous fixing tape, it is possible to further suppress the decrease in the impregnation property of the electrode assembly.

[0023] However, the effects obtainable through the present invention are not limited to the effects described above, and other technical effects not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

Brief Description of the Drawings

[0024] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described later, serve to further understand the technical idea of the present invention. Therefore, the present invention should not be construed as being limited only to the matters described in such drawings.

[0025] [Figure 1] It is a perspective view schematically showing the configuration of a battery pack. [Figure 2] It is a perspective view schematically showing the configuration of the battery of FIG. 1. [Figure 3] It is a cross-sectional view schematically showing the configuration of the battery of FIG. 2. [Figure 4] It is a perspective view schematically showing the configuration of an electrode assembly according to an embodiment. [Figure 5] It is a perspective view schematically showing the separation of the electrode assembly and the fixing tape in FIG. 4. [Figure 6] It is a plan view schematically showing the configuration of the electrode assembly of FIG. 4. [Figure 7a] It is a plan view schematically showing an example of a state where the fixing tape is arranged only on a part of the inner surface of the electrode assembly. [Figure 7b] This is a schematic plan view illustrating another example in which the fixing tape is positioned only on a portion of the inner surface of the electrode assembly. [Figure 7c] This is a schematic plan view illustrating yet another example in which the fixing tape is positioned only on a portion of the inner surface of the electrode assembly. [Figure 8a] This is a schematic plan view illustrating an example of a fixing tape with multiple holes. [Figure 8b] This is a schematic plan view illustrating another example of a fixing tape with multiple holes. [Figure 8c] This is a schematic plan view illustrating yet another example of a fixing tape with multiple holes formed within it. [Figure 9] This is a flowchart showing a method for manufacturing an electrode assembly according to one embodiment. [Figure 10] This diagram schematically shows an example of a jig configuration that may be used in step S40 of Figure 9. [Figure 11a] This diagram schematically shows another example of a jig configuration that may be used in step S40 of Figure 9. [Figure 11b] Figure 11a is a schematic diagram illustrating an example of how the fixing tape is held using the jig shown in the diagram. [Figure 11c] This diagram schematically shows another example of how the fixing tape is held using the jig shown in Figure 11a. [Modes for carrying out the invention]

[0026] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors may appropriately define the concepts of terms in order to best describe their invention. Accordingly, the embodiments described herein and the configurations illustrated in the drawings represent only some of the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and it should be understood that, at the time of filing, there may be a variety of equivalents and modifications that can substitute for them.

[0027] Furthermore, as used herein, “comprise, include” and / or “comprising, including” identify the presence of the shapes, figures, stages, actions, members, elements and / or groups thereof mentioned, and do not exclude the presence or addition of one or more other shapes, figures, actions, members, elements and / or groups thereof.

[0028] Furthermore, to aid in understanding the invention, the accompanying drawings are not shown to actual scale, and the dimensions of some components may be exaggerated. Also, the same component may be assigned the same reference numeral in different embodiments.

[0029] The statement that two comparison objects are "identical" means that they are "substantially identical." Therefore, substantially identical objects may include those with deviations considered low in this industry, for example, deviations of 5% or less. Furthermore, the uniformity of certain parameters within a given domain may mean uniformity in terms of averages.

[0030] Although terms such as "first," "second," etc., are used to describe a variety of components, these components are, of course, not limited by these terms. These terms are simply used to distinguish one component from another, and unless otherwise stated, the first component may be the second component.

[0031] Throughout the specification, unless otherwise stated, each component may be singular or plural.

[0032] To say that any configuration is positioned "above (or below)" or "above (or below)" a component means not only that the configuration is positioned in contact with the upper (or lower) surface of the component, but also that other configurations may be interposed between the component and any configuration positioned on (or below) it.

[0033] Furthermore, when one component is described as being “on,” “connected to,” or “coupled to” another component, it should be understood that the components may be directly connected to or linked to one another, but may also be “interposed” between them, and each component may be “connected,” “coupled,” or “linked” through the other components.

[0034] As used herein, the terms “and / or” include any and all combinations of one or more related listed items. Furthermore, the use of “may also” when describing embodiments of this disclosure refers to “one or more embodiments of this disclosure.” Expressions such as “one or more” and “one or more” before the element list modify the entire element list, but not the individual elements of the list.

[0035] Whenever the specification uses "A and / or B," it means A only, B only, or A and B unless otherwise specified. When it uses "C to D," it means C or greater and D or less, unless otherwise specified.

[0036] When syntax such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group A, B, and C", or "at least one selected from among A, B, and C" is used to specify a list of elements A, B, and C, the syntax can refer to any and all suitable combinations.

[0037] The term “use” may be considered synonymous with the term “utilize.” As used herein, “substantially,” “about,” and similar terms are used as approximations, not terms of degree, to account for the inherent variability of measured or calculated values ​​as perceived by the general art in question.

[0038] In this specification, terms such as first, second, third, etc., may be used to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, drawing layer, or section from other elements, components, regions, drawing layers, or sections. Accordingly, the first elements, components, regions, layers, or sections discussed below may be named second elements, components, regions, layers, or sections without departing from the teachings of the exemplary embodiments.

[0039] As illustrated in the drawings, spatial relative terms such as “beneath,” “below,” “lower,” “above,” and “upper” may be used herein for ease of explanation to describe the relationship between one element or feature and other elements or features. Spatially relative positions will be understood to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the figure. For example, if the device in the drawing is turned upside down, an element described as “below” or “below” other elements will be understood as “above” or “upper” other elements. Thus, the term “below” can encompass both up and down directions.

[0040] The terms used herein are for the purpose of describing the embodiments of this disclosure and are not intended to limit this disclosure.

[0041] Figure 1 is a schematic perspective view showing an example of the configuration of a battery pack containing multiple cylindrical batteries. Referring to Figure 1, the battery pack includes a housing 1 and batteries 2.

[0042] Housing 1 forms the general appearance of the battery pack and can provide a space in which the battery 2 can be housed. Housing 1 may include a housing body 11 and a cover 12.

[0043] The housing body 11 may have the form of a box with an open interior and one side open. The cross-sectional shape of the housing body 11 is not limited to the rectangle shown in Figure 1, but can be redesigned to various shapes such as polygons, circles, and ellipses.

[0044] The cover 12 is coupled to the housing body 11 and can close off the internal space of the housing body 11. For example, the cover 12 may be formed to have the form of a roughly plate and positioned to face the open side of the housing body 11. The cover 12 can be fixed to the housing body 11 by various types of coupling methods such as bolting, welding, and fitting.

[0045] Battery 2 can function as a unit structure that stores and supplies power in a battery pack. Multiple batteries 2 may be provided. Multiple batteries 2 may be arranged inside housing 1 in various patterns such as a grid or a zigzag. Multiple batteries 2 may be arranged side by side. The number of batteries 2 can be varied depending on the size and shape of housing 1. The detailed configuration of battery 2 will be described later.

[0046] Multiple batteries 2 can be electrically connected by busbars (not shown). Multiple batteries 2 can be connected in series or in parallel by busbars. For example, busbars can connect batteries 2 arranged in the same row inside the housing 1 in parallel, and connect two adjacent rows of batteries 2 in series. Busbars can be made of electrically conductive materials such as copper, aluminum, or nickel.

[0047] Figure 2 is a schematic perspective view showing the configuration of a battery according to one embodiment, and Figure 3 is a schematic cross-sectional view showing the configuration of the battery in Figure 2. Referring to Figures 2 and 3, the battery 2 may include a case 100, an electrode assembly 200, and a cap assembly 300.

[0048] The case 100 can form the general appearance of the battery 2. The case 100 can be made of an electrically conductive material. For example, the case 100 can be made of a material that includes at least one of steel, stainless steel, aluminum, or aluminum alloy. Accordingly, the case 100 can protect the electrode assembly 200 from external shocks and perform a heat dissipation function to release the heat generated by the charging and discharging operations of the electrode assembly 200 to the outside.

[0049] The case 100 may include a cylindrical side wall portion 110 with a central axis C formed in its center. The central axis C of the case 100 described below may mean the central axis of the side wall portion 110. Both ends of the side wall portion 110 perpendicular to the central axis C of the case 100 may be formed to be open.

[0050] The case 100 may further include a bottom portion 120 that closes the lower end of the side wall portion 110. The bottom portion 120 may be formed to have a substantially disc shape and be positioned opposite the lower end of the side wall portion 110. The bottom portion 120 may be positioned perpendicular to the central axis C of the case 100. The circumferential surface of the bottom portion 120 may be joined to the lower end of the side wall portion 110. The bottom portion 120 may be molded integrally with the side wall portion 110 by a drawing process or the like, or alternatively, it may be manufactured separately from the side wall portion 110 and then joined to the side wall portion 110 by welding or the like.

[0051] The case 100 may further include an opening 130 that opens the upper end of the side wall portion 110. The opening 130 can function in the upper end region of the case 100 as providing a path for the electrode assembly 200 (described later) to be inserted into the interior of the case 100 and providing a space in which the cap assembly 300 (described later) can be installed. The opening 130 may mean an open space surrounded by the upper end region of the side wall portion 110 located on the opposite side of the bottom portion 120.

[0052] The electrode assembly 200 can function as a unit structure that performs charging and discharging operations of power in the battery 2. The electrode assembly 200 may include a first electrode plate 210, a second electrode plate 220, and a separator membrane 230 positioned between the first electrode plate 210 and the second electrode plate 220.

[0053] The electrode assembly 200 may be placed inside the case 100. The electrode assembly 200 may be inserted into the case 100 through the opening 130 of the case 100.

[0054] The electrode assembly 200 may have a form in which it is wound around a winding shaft. More specifically, the electrode assembly 200 may have a form in which the first electrode plate 210, the separation membrane 230, the second electrode plate 220, and the separation membrane 230 are stacked and wound around the winding shaft in a clockwise or counterclockwise direction. Accordingly, the electrode assembly 200 may have a form that is substantially like a jelly roll (cylindrical). Here, the winding shaft may mean a straight line that penetrates the central part of the electrode assembly 200. The winding shaft of the electrode assembly 200 may be positioned coaxially with the central axis C of the case 100.

[0055] The first electrode plate 210 can function as the positive electrode of the electrode assembly 200. The first electrode plate 210 may be formed in the form of a foil containing a metallic material such as aluminum or an aluminum alloy. The type, size, and shape of the first electrode plate 210 are not particularly limited, as long as it is conductive without inducing a chemical change in the battery.

[0056] A first active material layer may be applied to at least a portion of the first electrode plate 210. The first active material layer may be applied to both sides of the first electrode plate 210, or alternatively, to only one side of the first electrode plate 210. As the first electrode plate 210 functions as a positive electrode, the first active material layer may contain a positive electrode active material.

[0057] The positive electrode active material can be a compound capable of reversible intercalation and deintercalation of lithium (lithiated intercalation compound). More specifically, one or more of composite oxides of metals selected from cobalt, manganese, nickel, iron, and combinations thereof with lithium can be used.

[0058] As an example, the positive electrode active material can include at least one of lithium-iron-phosphate (LiFePO4, LFP), lithium-manganese-iron-phosphate (LiMnFePO4, LMFP), lithium-nickel-cobalt-manganese oxide (LiNi x Co y Mn z O2, NCM). Here, 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1 can be satisfied. The positive electrode active material can include only one of lithium-iron-phosphate (LiFePO4, LFP), lithium-manganese-iron-phosphate (LiMnFePO4, LMFP), lithium-nickel-cobalt-manganese oxide (LiNi x Co y Mn z O2, LNCM), or can include any two of them, or all of them. x Co y Mn z O2, LNCM).

[0059] The first active material layer may further contain a positive electrode conductive material. The positive electrode conductive material is used to impart conductivity to the first active material layer, and any electronically conductive material that does not cause chemical changes can be used. Examples of positive electrode conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjenblack, carbon fibers, carbon nanofibers, and carbon nanotubes, metallic materials in the form of metal powders or metal fibers containing copper, nickel, aluminum, silver, etc., or conductive polymers such as polyphenylene derivatives, or mixtures thereof.

[0060] The first active material layer may further contain a positive electrode binder. The positive electrode binder plays a role in ensuring that the particles constituting the positive electrode active material adhere well to each other, and also in ensuring that the positive electrode active material adheres well to the first electrode plate 210. Examples of positive electrode binders include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0061] Examples of non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyimide, or combinations thereof.

[0062] The aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile-ethylene propylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0063] When using an aqueous binder as the positive electrode binder, it may further contain a cellulose series compound that can impart viscosity. This cellulose series compound can be a mixture of one or more carboxymethylcellulose, hydroxypropylmethylcellulose, methylcellulose, or their alkali metal salts. As the alkali metal, Na, K, or Li can be used.

[0064] The dry binder is a polymeric substance that can be formed into fibers, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0065] The first electrode plate 210 can be electrically connected to the cap assembly 300. By the first electrode plate 210 functioning as the positive electrode of the electrode assembly 200, the cap assembly 300 can function as the positive electrode terminal of the battery 2. As an example, the first electrode plate 210 can be electrically connected to the cap assembly 300 by a first electrode tab E1. The first electrode tab E1 can be made of a conductive metallic material such as copper, copper alloy, nickel, or nickel alloy. The first electrode tab E1 is positioned above the electrode assembly 200, and both ends can be connected to the first electrode plate 210 and the cap assembly 300, respectively. One end of the first electrode tab E1 can be directly connected to the first electrode plate 210, or it can be indirectly connected to the first electrode plate 210 via a separate current collector plate (not shown) connected to the first electrode plate 210. However, the first electrode plate 210 is not limited to these matters, and can also be directly connected to the cap assembly 300 without the first electrode tab E1.

[0066] The second electrode plate 220 can function as the negative electrode of the electrode assembly 200. The second electrode plate 220 may be formed in the form of a foil containing a metallic material such as copper, copper alloy, nickel, or nickel alloy. The second electrode plate 220 may be positioned opposite the first electrode plate 210 at a predetermined distance apart. The type, size, and shape of the second electrode plate 220 are not particularly limited, as long as it is conductive without inducing a chemical change in the battery.

[0067] A second active material layer may be coated on at least a portion of the second electrode plate 220. The second active material layer may be coated on both sides of the second electrode plate 220, or alternatively, on only one side of the second electrode plate 220. Since the second electrode plate 220 functions as a negative electrode, the second active material layer may contain a negative electrode active material.

[0068] The negative electrode active material may include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material that can be doped and dedoped with lithium, or a transition metal oxide.

[0069] Materials capable of reversibly intercalating / deintercalating lithium ions include carbon-based anode active materials such as crystalline carbon, amorphous carbon, or combinations thereof. Examples of crystalline carbon include graphite such as amorphous, plate-like, flake-like, spherical, or fibrous natural or artificial graphite, while examples of amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, and calcined coke.

[0070] As lithium metal alloys, alloys of lithium with a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn can be used.

[0071] For materials that can be doped and dedoped with lithium, Si-based or Sn-based anode active materials can be used. Si-based anode active materials include silicon, silicon-carbon composites, and SiO2. x (x=1 or 2), Si-Q alloy (where Q is selected from alkali metals, alkaline earth metals, group 13 elements, group 14 elements (excluding Si), group 15 elements, group 16 elements, transition metals, rare earth elements, and combinations thereof), or combinations thereof. The Sn-based anode active material may be Sn, SnO2, Sn-based alloy, or combinations thereof.

[0072] A silicon-carbon composite can be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, it may include secondary particles (core) assembled from primary silicon particles, and an amorphous carbon coating layer (shell) located on the surface of these secondary particles. Amorphous carbon may also be located between the primary silicon particles, for example, the primary silicon particles may be coated with amorphous carbon. The secondary particles may be dispersed in the amorphous carbon matrix.

[0073] The silicon-carbon composite may further contain crystalline carbon. For example, the silicon-carbon composite may include a core containing crystalline carbon and silicon particles, and an amorphous carbon coating layer located on the surface of this core.

[0074] Si-based or Sn-based anode active materials can be used in combination with carbon-based anode active materials.

[0075] The second active material layer may further include a negative electrode conductive material and a negative electrode binder.

[0076] The negative electrode conductive material is used to impart conductivity to the second active material layer, and any electronically conductive material that does not cause chemical changes can be used. Examples of negative electrode conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjenblack, carbon fibers, carbon nanofibers, and carbon nanotubes, metallic materials in the form of metal powders or metal fibers containing copper, nickel, aluminum, silver, etc., or conductive polymers such as polyphenylene derivatives, or mixtures thereof.

[0077] The negative electrode binder plays a role in ensuring that the particles constituting the negative electrode active material adhere well to each other, and also in ensuring that the negative electrode active material adheres well to the second electrode plate 220. Examples of negative electrode binders include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0078] Examples of non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyimide, or combinations thereof.

[0079] The aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile-ethylene propylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0080] When using an aqueous binder as the negative electrode binder, it may further contain a cellulose series compound that can impart viscosity. This cellulose series compound can be a mixture of one or more carboxymethylcellulose, hydroxypropylmethylcellulose, methylcellulose, or their alkali metal salts. The alkali metal can be Na, K, or Li.

[0081] The dry binder is a polymeric substance that can be formed into fibers, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0082] The second electrode plate 220 can be electrically connected to the case 100. For example, the second electrode plate 220 can be electrically connected to the case 100 by a second electrode tab E2. By the second electrode plate 220 functioning as the negative electrode of the electrode assembly 200, the case 100 can function as the negative electrode terminal of the battery 2. The second electrode tab E2 can be made of a conductive metallic material such as copper, copper alloy, nickel, or nickel alloy. The second electrode tab E2 is positioned on the underside of the electrode assembly 200, and both ends can be connected to the second electrode plate 220 and the bottom 120 of the case 100, respectively. One end of the second electrode tab E2 can be directly connected to the second electrode plate 220, or it can be indirectly connected to the second electrode plate 220 via a separate current collector plate (not shown) connected to the second electrode plate 220. However, the second electrode plate 220 is not limited to these matters, and can also be directly connected to the case 100 without the second electrode tab E2.

[0083] The separation membrane 230 may be placed between the first electrode plate 210 and the second electrode plate 220. The separation membrane 230 can perform the function of preventing a short circuit between the first electrode plate 210 and the second electrode plate 220 while allowing the movement of lithium ions between them.

[0084] Such separation membranes 230 may be polyethylene, polypropylene, polyvinylidene fluoride, or multilayer membranes of two or more layers thereof, and mixed multilayer membranes such as polyethylene / polypropylene two-layer separators, polyethylene / polypropylene / polyethylene three-layer separators, and polypropylene / polyethylene / polypropylene three-layer separators may be used.

[0085] The separation membrane 230 may include a porous substrate and a coating layer containing organic, inorganic, or a combination thereof located on one or both sides of the porous substrate.

[0086] The porous substrate may be a polymer film formed from one polymer selected from polyethylene, polyolefins such as polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyacetal, polyamide, polyimide, polycarbonate, polyetherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylene sulfide, polyethylene naphthalate, glass fiber, Teflon®, and polytetrafluoroethylene, or from copolymers or mixtures of two or more of these polymers.

[0087] The organic material may include polyvinylidene fluoride polymers or (meth)acrylic polymers.

[0088] Inorganic materials may include, but are not limited to, inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0089] Organic and inorganic materials can exist mixed together in a single coating layer, or they can exist in a layered configuration where one coating layer contains organic materials and the other contains inorganic materials.

[0090] The separation membranes 230 may be provided in pairs. The pair of separation membranes 230 may be positioned to face either the first electrode plate 210 or the second electrode plate 220, respectively. The pair of separation membranes 230 may be wound together with the first electrode plate 210 and the second electrode plate 220 around a winding shaft.

[0091] A first insulating plate 201 and a second insulating plate 202 may be placed on both sides of the electrode assembly 200 (upper and lower sides in Figure 3). The first insulating plate 201 and the second insulating plate 202 may include insulating materials such as rubber, polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET).

[0092] The first insulating plate 201 may be formed to have a substantially disc shape. The first insulating plate 201 may be placed between the upper surface of the electrode assembly 200 and the cap assembly 300. Accordingly, the first insulating plate 201 prevents the upper surface of the electrode assembly 200 from directly contacting the cap assembly 300, thereby insulating the electrode assembly 200 and the cap assembly 300 from each other. The first insulating plate 201 may have a through hole (not shown) through which the first electrode tab E1 can pass.

[0093] The second insulating plate 202 may be formed to have a substantially disc shape. The second insulating plate 202 may be placed between the lower surface of the electrode assembly 200 and the bottom 120 of the case 100. Accordingly, the second insulating plate 202 can prevent the lower surface of the electrode assembly 200 from directly contacting the bottom 120 of the case 100, thereby insulating the electrode assembly 200 and the bottom 120 of the case 100 from each other. The second insulating plate 202 may have a through hole (not shown) through which the second electrode tab E2 can pass.

[0094] A cap assembly 300 may be placed at the upper end of the side wall portion 110, i.e., the open portion 130. The open portion 130 of the case 100 is sealed by the cap assembly 300, and for this purpose, the cap assembly 300 can be coupled to the case 100.

[0095] A beading part 140 may be formed on the side wall portion 110 so as to be recessed toward the central axis C of the case 100. The beading part 140 is located on the underside of the cap assembly 300 and can restrict the cap assembly 300 from being inserted into the interior of the case 100 beyond a set distance.

[0096] A crimping part 150 may be formed above the beading portion 140, where the upper end of the side wall portion 110 is bent toward the central axis C of the case 100. The crimping part 150 is positioned above the cap assembly 300 and can prevent the cap assembly 300 from detaching from the case 100.

[0097] A gasket G may be placed between the case 100 and the cap assembly 300. The gasket G, through its own elastic restoring force, can fix the cap assembly 300 in place at the opening 130, electrically insulate the case 100 and the cap assembly 300 from each other, and function as a component that prevents moisture or electrolyte from flowing in or out between the case 100 and the cap assembly 300.

[0098] The gasket G may include insulating materials such as rubber, polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). The gasket G may be formed to have a substantially ring shape and positioned inside the beading portion 140 and / or crimping portion 150. The outer surface of the gasket G may be in close contact with the inner surface of the beading portion 140 and / or crimping portion 150, and the inner surface of the gasket G may be in close contact with the outer surface of the cap assembly 300.

[0099] As described above, the cap assembly 300 can be electrically connected to the first electrode plate 210 by the first electrode tab E1. With the first electrode plate 210 functioning as the positive electrode of the electrode assembly 200, the cap assembly 300 can function as the positive electrode terminal of a battery.

[0100] The cap assembly 300 is designed to interrupt the flow of current when the pressure inside the case 100 rises due to overcurrent or other reasons, thereby interrupting the electrical connection between the battery 2 and the external device. The cap assembly 300 may also be designed to rupture when the pressure inside the case 100 rises above a set level, thereby creating communication between the internal space of the case 100 and the external space of the case 100. Accordingly, the cap assembly 300 can reduce the risk of the battery 2 exploding in the event of an overcurrent.

[0101] Figure 4 is a schematic perspective view illustrating the configuration of an electrode assembly according to one embodiment; Figure 5 is a schematic perspective view showing the electrode assembly and fixing tape separated from each other in Figure 4; and Figure 6 is a schematic plan view illustrating the configuration of the electrode assembly in Figure 4.

[0102] Referring to Figures 4 to 6, the electrode assembly 200 is a cylindrical electrode assembly formed by winding multiple times a laminate in which a positive electrode 210, a separator membrane 230, a negative electrode 220, and another separator membrane 230 are stacked in that order. Such an electrode assembly is sometimes called a jelly-roll electrode assembly.

[0103] The positive electrode 210, the negative electrode 220, and the separator membrane 230 can all have the shape of a sheet with a relatively long long side. "Sheet-like" can refer to a structure having a certain thickness and a roughly rectangular planar shape. The length of the short side can vary depending on the height of the battery including the electrode assembly 200. The length of the long side can vary depending on the number of windings of the laminate constituting the electrode assembly 200. Typically, among the positive electrode 210, the negative electrode 220, and the separator membrane 230, the separator membrane 230 has the longest long side.

[0104] The cylindrical electrode assembly 200 can be manufactured by alternatingly stacking sheet-shaped positive electrodes 210, sheet-shaped separation membranes 230, sheet-shaped negative electrodes 220, and sheet-shaped separation membranes 230 in a laminate, and then gripping the excess portion of the separation membranes 230 that protrudes longitudinally from the positive electrodes 210 and negative electrodes 220 with a rod-shaped winding core member and winding it multiple times. In this case, the rod-shaped winding core member can serve as the winding axis of the electrode assembly 200, and the winding axis can be aligned with the short side of the separation membranes 230. When the electrode assembly 200 is inserted into the case 100, the winding axis can be aligned with the central axis of the case (C, see Figure 3).

[0105] After the laminate is wound up and the rod-shaped member is removed, the center (winding core A) of the jelly roll-shaped electrode assembly 200 becomes empty. However, the excess portion of the separation membrane 230 that was held by the winding member crosses the winding core A, and the separation membrane 230 that crosses the winding core A may take on the shape of a Taiji pattern in its plane. Subsequently, a reforming process is carried out in which a reforming pin is inserted into the winding core A to make the excess portion of the separation membrane 230 adhere tightly to the inner surface of the electrode assembly 200. As a result, there is no further excess portion of the separation membrane 230 in the winding core A of the electrode assembly 200, and it becomes empty.

[0106] According to this embodiment, the electrode assembly 200 further includes a fixing tape 240 for fixing the reformed separation membrane 230 to the inner surface of the electrode assembly 200. The fixing tape 240 serves to fix the excess portion of the separation membrane 230 that is in close contact with the inner surface of the electrode assembly 200 so as not to loosen during the reforming process. In other words, the fixing tape 240 prevents the excess portion of the separation membrane 230 from detaching from the inner surface and coming out towards the core A after the reforming process.

[0107] According to this, damage to the separation membrane 230 by the welding rod can be prevented in subsequent processes, such as welding electrode tabs. Furthermore, the phenomenon of the separation membrane 230 collapsing during the electrolyte injection process can also be prevented. As a result, not only can the productivity of the electrode assembly 200 be improved, but its stability can also be enhanced.

[0108] The fixing tape 240 may include an electrically insulating film. For example, the fixing tape 240 may have an adhesive applied to one side of the electrically insulating film, or an adhesive layer attached to it. This configuration prevents current leakage from occurring in the core portion A of the electrode assembly 200.

[0109] There are no particular restrictions on the material of the electrical insulating film. For example, the electrical insulating film may be formed from polyimide (PI) resin, polyethylene (PE) resin, or polyester (PET) resin. However, it is not limited to these materials, and the electrical insulating film may also be formed from materials such as polyolefin resin, polyvinyl chloride resin, EVA (Ethylene-Vinyl Acetate copolymer-based) resin, or silicone rubber.

[0110] According to one embodiment, the electrically insulating film may be made of a material that does not react with the electrolyte of the battery 2. In this case, even when the electrolyte is injected into the case 100 of the battery 2 and the electrode assembly 200 is impregnated with the electrolyte, the fixing tape 240 can continue to prevent the separation membrane 230 from separating.

[0111] The fixing tape 240 can have a shape that surrounds the entire inner surface of the electrode assembly 200. More specifically, the fixing tape 240 can have an overall cylindrical shape (see Figure 5). Such a cylindrical fixing tape 240 can be placed on the core A of the electrode assembly 200 to fix the separation membrane 230 across the entire inner surface of the electrode assembly 200. In this case, the height of the fixing tape 240 may be the same as the width of the separation membrane 230, or even smaller.

[0112] In contrast, the fixing tape 240 may be placed only on a portion of the inner surface of the electrode assembly 200. In this case, the fixing tape 240 adheres to the end of the separation membrane 230 exposed on the core portion A of the electrode assembly 200, effectively preventing the separation membrane 230 from loosening again. Furthermore, since the fixing tape 240 only obstructs a portion of the separation membrane 230, it is possible to minimize any reduction or unevenness in the impregnation rate of the electrode assembly 200 caused by the fixing tape 240 during the subsequent electrolyte injection process.

[0113] Figures 7a to 7c are schematic plan views showing how the fixing tape is positioned on only a portion of the inner surface of the electrode assembly. Figures 7a to 7c are schematic diagrams showing the inner surface of the electrode assembly as viewed from the core of the electrode assembly. In Figures 7a to 7c, the vertical line L may correspond to the profile of one end of the separation membrane 230, i.e., one short side of the separation membrane 230.

[0114] Referring to Figure 7a, the fixing tape 240a may include an upper fixing tape 240a1 and a lower fixing tape 240a2 attached to the inner surface of the electrode assembly 200, i.e., the separation membrane 230. The upper fixing tape 240a1 and the lower fixing tape 240a2 can both be attached to the separation membrane 230 exposed laterally on the core, intersecting one short side L of the separation membrane 230. This effectively prevents one end of the separation membrane 230 from falling onto the inner surface of the electrode assembly 200.

[0115] The upper fixing tape 240a1 is attached to the upper side of the separation membrane 230. The upper fixing tape 240a1 may be attached in line with the upper edge of the separation membrane 230, or slightly below the upper edge. The lower fixing tape 240a2 is attached to the lower side of the separation membrane 230. The lower fixing tape 240a2 may be attached in line with the lower edge of the separation membrane 230, or slightly above the lower edge.

[0116] According to this embodiment, by minimizing the area occupied by the fixing tape 240a for fixing the separation membrane 230, the reduction in impregnation performance due to the insertion of the fixing tape 240a can be minimized. On the other hand, since the separation membrane 230 can be fixed at least on the upper and lower sides while crossing at least the short side L of the separation membrane 230, the fixing tape 240a can provide the minimum adhesive force necessary for fixing the separation membrane 230.

[0117] Referring to Figure 7b, the fixing tape 240b may include an upper fixing tape 240b1, a lower fixing tape 240b2, and an intermediate fixing tape 240b3 attached to the inner surface of the electrode assembly 200, i.e., the separation membrane 230. The upper fixing tape 240b1, the lower fixing tape 240b2, and the intermediate fixing tape 240b3 can all be attached to the separation membrane 230 exposed laterally on the core, intersecting one short side L of the separation membrane 230. This more effectively prevents one end of the separation membrane 230 from falling onto the inner surface of the electrode assembly 200.

[0118] The upper fixing tape 240b1 is attached to the upper side of the separation membrane 230. The upper fixing tape 240b1 may be attached in line with the upper edge of the separation membrane 230, or slightly below the upper edge and spaced apart. The lower fixing tape 240b2 is attached to the lower side of the separation membrane 230. The lower fixing tape 240b2 may be attached in line with the lower edge of the separation membrane 230, or slightly above the lower edge and spaced apart. The intermediate fixing tape 240b3 is attached to the separation membrane 230 between the upper fixing tape 240b1 and the lower fixing tape 240b2.

[0119] According to this embodiment, by minimizing the area occupied by the fixing tape 240b for fixing the separation membrane 230, the decrease in impregnation performance due to the insertion of the fixing tape 240b can be suppressed. On the other hand, since the fixing tape 240b can be used to fix the separation membrane 230 not only on the top and bottom sides but also in the middle while crossing at least the short sides L of the separation membrane 230, the adhesive force required to fix the separation membrane 230 can be further strengthened by the fixing tape 240b.

[0120] Referring to Figure 7c, the fixing tape 240c can be attached to the core portion of the separation membrane 230, alongside one short side L of the separation membrane 230. That is, the fixing tape 240c can be attached longitudinally, covering one short side L of the separation membrane 230. In Figure 7c, the fixing tape 240c is shown as a single unit, but it can be divided into multiple pieces and attached along one short side L of the separation membrane 230. This effectively prevents one end of the separation membrane 230 from falling onto the inner surface of the electrode assembly 200.

[0121] According to this embodiment, by minimizing the area occupied by the fixing tape 240c for fixing the separation membrane 230, the reduction in impregnation performance due to the insertion of the fixing tape 240c can be minimized. Furthermore, since the fixing tape 240c can fix the separation membrane 230 while covering most of the short side L of the separation membrane 230, the edges of the separation membrane 230 can be fixed more strongly.

[0122] Continuing to refer to Figure 5, the fixing tape 240 may include a porous film. When the fixing tape 240 is formed of a porous film, the electrolyte can pass through the fixing tape 240 through the holes H in the fixing tape 240, thus preventing a decrease in electrolyte impregnation. However, it is not limited to this, and the fixing tape 240 may be a general tape without holes.

[0123] A porous film can refer to a structure in which multiple holes H are formed in a base film. Here, holes H can be through-holes that penetrate the base film. There are no particular restrictions on the size of holes H, but they can be large enough for an electrolyte to pass through or larger.

[0124] When considering the impregnation characteristics of the electrolyte, it is preferable that the holes H formed in the fixing tape 240 be as large and numerous as possible. However, if the size of the holes H is excessively large or the number of holes is large, the adhesive strength of the fixing tape 240 may not be sufficient. Taking this into consideration, the area occupied by multiple holes H on the fixing tape 240 may be approximately 10-90%.

[0125] Figures 8a to 8c are schematic plan views showing the appearance of fixing tape with multiple holes formed in it.

[0126] Referring to Figures 8a to 8c, the multiple holes H1, H2, and H3 may be arranged regularly across the entire surface of the fixing tape 240. The regular arrangement is not particularly limited, but may be arranged in a single line in the horizontal and / or vertical directions, or in a zigzag pattern in either the horizontal or vertical direction. Alternatively, the multiple holes H1, H2, and H3 may be arranged randomly across the entire surface of the fixing tape 240.

[0127] There are no particular restrictions on the planar shapes of the multiple holes H1, H2, and H3. For example, the multiple holes H1, H2, and H3 can be circular, elliptical, quadrilateral, triangular, or other polygonal shapes. Furthermore, the sizes of the multiple holes H1, H2, and H3 may be uniform throughout or non-uniform.

[0128] Next, a method for manufacturing an electrode assembly according to one embodiment will be described.

[0129] Figure 9 is a flowchart showing a method for manufacturing an electrode assembly according to one embodiment.

[0130] Referring to Figures 4 to 6 and Figure 9, first a laminate is prepared in which a separation membrane is interposed between the positive electrode and the negative electrode (S10). The laminate may be, for example, a laminate in which a sheet-shaped positive electrode 210, a sheet-shaped separation membrane 230, a sheet-shaped negative electrode 220, and a sheet-shaped separation membrane 230 are alternately stacked. In the laminate, the length of the long side of the separation membrane 230 is longer than that of the positive electrode 210 or the negative electrode 220, and at least one side may have a predetermined length of margin (i.e., a portion that protrudes to one side from the positive electrode 210 or the negative electrode 220).

[0131] Then, one end of the separation membrane 230, i.e., the excess portion, is grasped from the laminate and the laminate is wound up multiple times (S20). As a result of the winding process (S20), a jelly roll electrode assembly, i.e., a cylindrical electrode assembly, is produced. There are no particular restrictions on the type of winding member used to grasp one end of the separation membrane 230 in the winding process (S20). There are also no particular restrictions on the number of times the laminate is wound in the winding process (S20), and it may vary depending on the size and performance of the jelly roll electrode assembly to be manufactured. After the winding process (S20) is completed, the separation membrane is released from the winding member.

[0132] Then, the reform process is carried out on the cylindrically wound electrode assembly (S30). More specifically, the separation membrane 230 exposed at the winding center of the cylindrically wound electrode assembly is brought into close contact with the inner surface of the electrode assembly. As a result, an empty space is created at the winding center.

[0133] Then, the fixing tape 240 is inserted into the empty winding center to fix the separation membrane 230, which is in close contact with the inner surface of the electrode assembly, with the fixing tape 240 (S40). At this time, the fixing tape 240 adheres to the end of the separation membrane 230, that is, to cover part or all of the short side of the separation membrane 230 that is exposed at the winding center, thereby preventing the subsequently adhered separation membrane 230 from loosening and flying out at the winding center. The size, shape, placement, and porous structure of such fixing tape 240 have been explained in detail above, so a detailed explanation is omitted here.

[0134] According to one embodiment, the process of attaching the fixing tape 240 in step S40 can be carried out using a predetermined jig that can grasp the fixing tape 240, insert it into the winding center, and attach it to the separation membrane 230.

[0135] Figure 10 is a schematic diagram showing an example of a jig configuration that may be used in step S40. Referring to Figure 10, the jig J1 may be a tweezers structure that can physically grasp both ends of the fixing tape 240. The shape and operating method of the tweezers structure are not particularly limited as long as it can grasp both ends of the fixing tape 240 and separate the fixing tape 240 from the tweezers structure by manipulation. As an example, in Figure 10, the tweezers structure is shown as a combination of a first tweezers part J1a and a second tweezers part J1b.

[0136] Using the jig J1 with the tweezers structure shown in Figure 10, the fixing tape 240 can be held in close contact with the jig J1, and both ends can be grasped using the first tweezers portion J1a and the second tweezers portion J1b. At this time, the inner surface of the fixing tape 240 that is in close contact with the jig J1 is not adhesive, but the outer surface of the fixing tape 240 has adhesive properties because an adhesive or the like is applied to it. After inserting the jig J1 in the state shown in Figure 10 into the winding core of the electrode assembly 200, the first tweezers portion J1a and the second tweezers portion J1b ​​can be manipulated to separate both ends of the grasped fixing tape 240, and the outer surface of the fixing tape 240 can be brought into contact with the separation membrane 230, thereby causing the outer surface of the fixing tape 240 to adhere to the separation membrane 230.

[0137] Figure 11a is a schematic diagram showing another example of the jig configuration that may be used in step S40. Figures 11b and 11c are schematic diagrams showing the state in which the fixing tape is being held using the jig in Figure 11a. Referring to Figures 11a to 11c, the jig J2 may be a cylindrical structure that can hold the fixing tape 240 to its outer surface with a predetermined suction force. The cylindrical jig J2 has many holes formed on its surface and is hollow inside, so as long as it can draw in air through the inside and the fixing tape 240 can be held to the outer surface of the jig J2 by ​​the suction force of the air drawn in through the holes, there are no particular restrictions on the shape of the holes or the way they operate. For example, as shown in Figure 11b, the suction force in the jig J2 may be generated on the entire outer surface of the jig J2, or as shown in Figure 11c, the suction force in the jig J2 may be generated on a part of the outer surface of the jig J2.

[0138] By using the tweezers-like jig J2 shown in Figure 11a, the fixing tape 240 can be held by adhering it to the entire or partial outer surface of the jig J2 using the suction force generated through the hole. At this time, the inner surface of the fixing tape 240 that is in close contact with the jig J2 is not adhesive, but the outer surface of the fixing tape 240 can be adhesive because an adhesive or the like is applied to it. After inserting the jig J2 in the state shown in Figure 11a into the winding core of the electrode assembly 200, the suction force is removed to detach it from the jig J2, and if necessary, the outer surface of the fixing tape 240 can be brought into contact with the separation membrane 230 so that the outer surface of the fixing tape 240 adheres to the separation membrane 230.

[0139] Although the present invention has been described with reference to the embodiments illustrated in the drawings, these are merely illustrative examples, and a person with ordinary skill in the art will understand that a variety of modifications and equivalent other embodiments are possible.

[0140] Therefore, the scope of technical protection of the present invention should be defined by the claims described above. [Explanation of symbols]

[0141] 1 Housing 2 batteries 11 Housing 12 Covers 100 cases 110 Side wall section 120 bottom 130 Open area 140 Beading section 150 Crimping section 200 electrode assembly 201 First insulating plate 202 Second insulating plate 210 First electrode plate (positive electrode) 220 Second electrode plate (negative electrode) 230 Separation membrane 240, 240a, 240b, 240c fixing tape 240a1, 240b1 Upper fixing tape 240a2, 240b2 Lower fixing tape 240b3 Intermediate fixing tape 300 Cap Assembly A. Core portion of electrode assembly 200 C Case 100 central axis E1 First electrode tab E2 Second electrode tab G Gasket Halls H, H1, H2, and H3 J1, J2 jigs J1a First tweezers section J1b Second tweezers section L Short side of separation membrane 230

Claims

1. A cylindrical electrode assembly is formed by winding a laminate in which a separation film is interposed between the positive and negative electrodes multiple times so as to have a winding center, An electrode assembly characterized by including a fixing tape for fixing the separation membrane exposed at the winding center to the inner surface of the electrode assembly.

2. The electrode assembly according to claim 1, characterized in that the fixing tape includes an electrically insulating film.

3. The electrode assembly according to claim 2, characterized in that the electrically insulating film is formed of a polyimide (PI) resin, a polyethylene (PE) resin, or a polyester (PET) resin.

4. The electrode assembly according to claim 1, characterized in that the fixing tape includes a porous film.

5. The electrode assembly according to claim 4, characterized in that the porous film has a plurality of holes formed in the base film.

6. The electrode assembly according to claim 5, characterized in that the area occupied by the plurality of holes relative to the base film is 10 to 90%.

7. The electrode assembly according to claim 5, characterized in that the plurality of holes are of uniform size and are regularly arranged across the entire surface of the base film.

8. The electrode assembly according to claim 5, characterized in that the plurality of holes are not of uniform size or are irregularly arranged across the entire surface of the base film.

9. The electrode assembly according to claim 5, characterized in that the planar shape of the plurality of holes is circular, elliptical, or polygonal.

10. The electrode assembly according to claim 1, characterized in that the fixing tape includes an upper fixing tape and a lower fixing tape attached to the upper and lower sides of the separation membrane, respectively, so as to intersect with the end of the separation membrane.

11. The electrode assembly according to claim 10, characterized in that the fixing tape further includes one or more intermediate fixing tapes attached between the upper fixing tape and the lower fixing tape.

12. The electrode assembly according to claim 1, characterized in that the fixing tape is attached along the edge of the separation membrane.

13. The steps include: preparing a laminate in which a separation film is interposed between the positive and negative electrodes; The steps include: grasping one end of the separation membrane and winding the laminate multiple times to form a cylindrical electrode assembly; The steps include: bringing the separation membrane exposed at the winding center of the electrode assembly into close contact with the inner surface of the electrode assembly; A method for manufacturing an electrode assembly, comprising the step of inserting a fixing tape into the winding center and fixing the separation membrane, which is in close contact with the inner surface of the electrode assembly, with the fixing tape.

14. The method for manufacturing an electrode assembly according to claim 13, characterized in that the fixing tape includes an electrically insulating film.

15. The method for manufacturing an electrode assembly according to claim 13, characterized in that the fixing tape includes a porous film.

16. The porous film has multiple holes formed in the base film, The method for manufacturing an electrode assembly according to claim 15, characterized in that the area occupied by the plurality of holes relative to the base film is 10 to 90%.

17. The method for manufacturing an electrode assembly according to claim 13, characterized in that the fixing tape is grasped by a jig having a tweezers structure or is attached to a jig having an adhesive function and inserted into the winding center.

18. A cylindrical case, The assembly includes a cylindrical electrode assembly formed by winding multiple times a laminate, which is housed inside the cylindrical case and has a separation membrane interposed between the positive and negative electrodes, A battery characterized in that the electrode assembly includes a fixing tape that fixes a separation membrane exposed at the winding center of the electrode assembly to the inner surface of the electrode assembly.

19. The battery according to claim 18, characterized in that the fixing tape includes an electrically insulating and porous film.

20. The porous film has multiple holes formed in the base film, The battery according to claim 19, characterized in that the area occupied by the plurality of holes relative to the base film is 10 to 90%.

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