Secondary battery and method for manufacturing secondary battery

Abstract

A secondary battery and a method of manufacturing the same are disclosed. The method of manufacturing a secondary battery includes: preparing an electrode assembly including a first electrode plate, a second electrode plate, and a separator; attaching a top tape to an upper end portion of the electrode assembly; attaching a bottom tape to surround a lower end portion of the electrode assembly; attaching the main body tape to surround an upper end portion of the electrode assembly; and inserting the electrode assembly into the case, wherein each of the first and second electrode plates includes a current collector, an active material layer on the current collector, an uncoated portion adjacent to the electrode active material layer at an end portion of the current collector, and an electrode tab at an end portion of the uncoated portion.

Description

[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2024-0053208, filed on April 22, 2024, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. TECHNICAL FIELD

[0002] Various embodiments of the present disclosure relate to a secondary battery and a method of manufacturing a secondary battery. BACKGROUND

[0003] Unlike a primary battery that is not designed to be (re)charged, a secondary (or rechargeable) battery is a battery designed to be discharged and recharged. Low-capacity secondary batteries are used for portable small electronic devices such as smartphones, feature phones, notebook computers, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources for driving electric motors in hybrid and electric vehicles and for storing electric power (e.g., home and / or utility-scale power storage). A secondary battery generally includes an electrode assembly composed of a positive electrode and a negative electrode, a case that accommodates the electrode assembly, and an electrode terminal connected to the electrode assembly.

[0004] The above information disclosed in this Background section is only for enhancing the understanding of the background of the present disclosure, therefore, it can contain information that does not constitute the related (or prior) art. SUMMARY

[0005] An aspect of an embodiment provides a method of manufacturing a secondary battery, the method including: preparing an electrode assembly having a first electrode plate, a second electrode plate, and a separator disposed between the first electrode plate and the second electrode plate; attaching a top tape to an upper end portion of the electrode assembly; attaching a bottom tape to the electrode assembly to surround a lower end portion of the electrode assembly; attaching a body tape to the electrode assembly to surround the upper end portion of the electrode assembly; and inserting the electrode assembly into a pouch, wherein the first electrode plate includes a first electrode current collector, a first electrode active material layer coated on each of two surfaces of the first electrode current collector, a first electrode uncoated portion formed on each of two end portions of the first electrode current collector and uncoated with the first electrode active material layer, and a first electrode tab provided at one end portion of the first electrode uncoated portion, and the second electrode plate includes a second electrode current collector, a second electrode active material layer coated on each of two surfaces of the second electrode current collector, a second electrode uncoated portion formed on each of two end portions of the second electrode current collector and uncoated with the second electrode active material layer, and a second electrode tab provided at one end portion of the second electrode uncoated portion.

[0006] Aspects of the embodiments provide a method of manufacturing a secondary battery, the method comprising: preparing an electrode assembly including a first electrode plate, a second electrode plate, and a separator between the first electrode plate and the second electrode plate; attaching a top tape to an upper end portion of the electrode assembly; attaching a bottom tape to a lower end portion of the electrode assembly, the bottom tape surrounding the lower end portion of the electrode assembly; attaching a body tape to the upper end portion of the electrode assembly, the body tape surrounding the upper end portion of the electrode assembly; and inserting the electrode assembly into a case, wherein the first electrode plate includes a first electrode current collector, a first electrode active material layer on the first electrode current collector, a first electrode uncoated portion adjacent to the first electrode active material layer at an end portion of the first electrode current collector, and a first electrode tab at an end portion of the first electrode uncoated portion, and wherein the second electrode plate includes a second electrode current collector, a second electrode active material layer on the second electrode current collector, a second electrode uncoated portion adjacent to the second electrode active material layer at an end portion of the second electrode current collector, and a second electrode tab at an end portion of the second electrode uncoated portion.

[0007] In some examples, the upper end portion of the electrode assembly can include a sliding region in which a thickness of the first electrode active material layer and the second electrode active material layer is reduced.

[0008] In some examples, attaching a body tape can include attaching the body tape around an uppermost layer of the electrode assembly.

[0009] In some examples, attaching a body tape can include attaching the body tape to the top tape to overlap at least a portion of the top tape.

[0010] In some examples, attaching a top tape can include attaching the top tape between the first electrode tab and the second electrode tab.

[0011] In some examples, attaching a top tape can include attaching the top tape around an upper surface of the electrode assembly and a pair of long side surfaces of the electrode assembly connected to the upper surface of the electrode assembly.

[0012] In some examples, the method can further include, prior to attaching a top tape, attaching a side tape to at least one of a side end portion of the electrode assembly.

[0013] In some examples, attaching a body tape can include attaching the body tape to overlap at least a portion of the side tape.

[0014] In some examples, the method can further include, after attaching the body tape, attaching a side tape to at least one of the side end portions of the electrode assembly.

[0015] In some examples, attaching the side tape can include attaching the side tape to overlap at least a portion of the body tape.

[0016] In some examples, attaching the top tape can include attaching the top tape to surround edges of the electrode assembly in a lead-out direction of the first and second electrode tabs.

[0017] In some examples, attaching the top tape can include attaching the top tape to secure a portion of the separator that protrudes outward beyond the first and second electrode plates from the upper end portion of the electrode assembly.

[0018] In some examples, in a longitudinal direction of the electrode assembly, the body tape can have a length that is 14% to 16% of a length of the electrode assembly.

[0019] In some examples, the top tape, the body tape, and / or the bottom tape can be formed by applying an adhesive to a synthetic resin selected from polyethylene terephthalate (PET), polypropylene (PP), and polyimide (PI).

[0020] Aspects of the embodiments provide a secondary battery, including: an electrode assembly having a first electrode plate; a second electrode plate; a separator disposed between the first electrode plate and the second electrode plate; a top tape attached to an upper end portion of the electrode assembly; a bottom tape attached to the electrode assembly to surround a lower end portion of the electrode assembly; a body tape attached to the top tape to surround the upper end portion of the electrode assembly; and a side tape attached to the electrode assembly to surround at least one of side end portions of the electrode assembly; and a case configured to accommodate the electrode assembly and including a sealing portion formed along an edge portion thereof, wherein the first electrode plate includes a first electrode current collector, a first electrode active material layer coated on each of two surfaces of the first electrode current collector, a first electrode uncoated portion formed on each of two end portions of the first electrode current collector and uncoated with the first electrode active material layer, and a first electrode tab provided at one end portion of the first electrode uncoated portion, and the second electrode plate includes a second electrode current collector, a second electrode active material layer coated on each of two surfaces of the second electrode current collector, a second electrode uncoated portion formed on each of two end portions of the second electrode current collector and uncoated with the second electrode active material layer, and a second electrode tab provided at one end portion of the second electrode uncoated portion.

[0021] Aspects of the embodiments provide a secondary battery, including: an electrode assembly including a first electrode plate, a second electrode plate, and a separator between the first electrode plate and the second electrode plate; a top tape attached to an upper end portion of the electrode assembly; a bottom tape surrounding a lower end portion of the electrode assembly; a main body tape attached to the top tape and surrounding the upper end portion of the electrode assembly; a side tape attached to the electrode assembly and surrounding at least one of side end portions of the electrode assembly; and a case housing the electrode assembly, the case including a sealing portion along an edge portion thereof, wherein the first electrode plate includes a first electrode current collector, a first electrode active material layer on the first electrode current collector, a first electrode uncoated portion adjacent to the first electrode active material layer at an end portion of the first electrode current collector, and a first electrode tab at an end portion of the first electrode uncoated portion, and wherein the second electrode plate includes a second electrode current collector, a second electrode active material layer on the second electrode current collector, a second electrode uncoated portion adjacent to the second electrode active material layer at an end portion of the second electrode current collector, and a second electrode tab at an end portion of the second electrode uncoated portion.

[0022] In some examples, the upper end portion of the electrode assembly can include a sliding region in which a thickness of the first electrode active material layer and the second electrode active material layer is reduced.

[0023] In some examples, the main body tape can be attached around an uppermost layer of the electrode assembly.

[0024] In some examples, the top tape can be attached between the first electrode tab and the second electrode tab.

[0025] In some examples, the top tape can be attached around a pair of long side surfaces of the electrode assembly and a top surface of the electrode assembly connected to the top surface of the electrode assembly.

[0026] In some examples, the main body tape can be attached to overlap at least a portion of the top tape and at least a portion of the side tape. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings, below, illustrate embodiments of the present disclosure and together with the detailed description below further describe aspects and features of the present disclosure. The present disclosure should therefore not be construed as being limited to the drawings:

[0028] Figure 1 is a perspective view of a secondary battery according to an embodiment of the present disclosure;

[0029] is a perspective view of a secondary battery according to an embodiment of the present disclosure;Figure 2 is a perspective view of a secondary battery according to an embodiment of the disclosure;

[0030] Figure 3 is a plan view of an electrode assembly according to an embodiment of the disclosure;

[0031] Figure 4 is a diagram schematically showing a procedure for attaching a tape according to an embodiment of the disclosure;

[0032] Figure 5 is a plan view for explaining a tape attaching process according to an embodiment of the disclosure;

[0033] Figures 6A-6C is a plan view showing a comparative example of an electrode assembly;

[0034] Figure 7 is a heatmap showing results of measuring flatness of embodiments and comparative examples;

[0035] Figure 8 is a data table showing results of checking thickness balance between parts of a battery cell according to embodiments and comparative examples;

[0036] Figures 9A-9E are diagrams and tables exemplifying results of evaluating thermal exposure limits of embodiments and comparative examples;

[0037] Figure 10 is a diagram showing short-circuit points and deconstruction analysis of a comparative example based on thermal exposure limit evaluation;

[0038] Figure 11 is a diagram schematically showing a smartphone equipped with a secondary battery according to an embodiment of the disclosure;

[0039] Figure 12A and Figure 12B is a perspective view of a battery pack according to an embodiment of the disclosure; and

[0040] Figure 13A and Figure 13B show examples of vehicle bodies and vehicle parts to which one or more embodiments of the disclosure can be applied. DETAILED DESCRIPTION

[0041] Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings. The terms or words used in the present specification and claims should not be interpreted as being limited to the commonly used meanings or meanings in dictionaries and should be interpreted based on the concept of the inventor to appropriately define the terms in order to describe the example embodiments in the best way feasible, that is, the meaning and concept consistent with the technical idea of the disclosure.

[0042] The embodiments described in this specification and the configurations shown in the drawings are merely some embodiments of the present disclosure and do not represent all technical ideas, aspects, and features of the present disclosure. Accordingly, it should be understood that, at the time of filing this application, various equivalents and modifications that can substitute or modify the embodiments described herein can exist.

[0043] It will be understood that when an element or layer is referred to as being “on” another element or layer, “connected to” or “coupled to” another element or layer, it can be directly on the other element or layer, connected or coupled to the other element or layer, or one or more intervening elements or layers can also be present. In the case where an element or layer is referred to as being “directly on” another element or layer, “directly connected to” or “directly coupled to” another element or layer, there are no intervening elements or layers present. For example, when a first element is described as being “coupled” or “connected” to a second element, the first element can be directly coupled or connected to the second element, or the first element can be indirectly coupled or connected to the second element via one or more intervening elements.

[0044] In the drawings, the size of various elements, layers, etc. can be exaggerated for clarity of illustration. The same reference numerals indicate the same elements. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Further, use of “may” in describing embodiments of the present disclosure relates to “one or more embodiments of the present disclosure.” Expressions such as “at least one of,” and “one or more of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. When a phrase such as “at least one of A, B, and C” or “at least one of A, B, or C” is used to indicate an element that is selected from A, B, and C, the phrase can refer to A, B, and C individually, or any and all combinations or subsets of A, B, and C. As used herein, the term “use” can be considered synonymous with the term “utilize.” As used herein, the terms “substantially,” “approximately,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent variations in a measurement or calculation that would be recognized by those of ordinary skill in the art.

[0045] It will be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, 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, layer or section from another element, component, region, layer or section. Therefore, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of example embodiments.

[0046] Spatially relative terms, such as "under", "below", "lower", "above", "upper", and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if a device in the figures is inverted, then a lower surface would then be oriented upward - i.e., it would be oriented "above" other elements or features. Thus, the term "below" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0047] The terminology used herein is for the purpose of describing embodiments of the disclosure and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0048] Furthermore, any numerical ranges herein are intended to include all sub-ranges of the same numerical precision, i.e. 1.0 to 10.0 is intended to include 2.4 to 7.6, etc. Any maximum numerical limitation should be interpreted as a minimum limitation and any minimum numerical limitation should be interpreted as a maximum limitation. Accordingly, the applicant reserves the right to amend this specification to expressly recite any sub-range including any and all sub-ranges expressly recited therein. All ranges are intended to encompass the endpoints and intermediate ranges thereof.

[0049] Referring to two compared elements, features, etc. as "the same" can mean that they are "substantially the same". Thus, the phrase "substantially the same" can include having a deviation that is considered low in the art, e.g., 5% or less. Further, when a parameter is said to be uniform in a given region, this can mean that it is uniform in terms of average value.

[0050] Throughout the specification, unless otherwise stated, each element may be singular or plural.

[0051] When any element is referred to as being disposed (or positioned or arranged) "on (or under)" or "on (or under)" a component, it may mean that the element is placed in contact with the upper (or lower) surface of the component, or it may mean that another component may be interposed between the component and any element disposed (or positioned or arranged) on (or under) the component.

[0052] Furthermore, it will be understood that when an element is referred to as being “coupled,” “linked,” or “connected” to another element, the elements may be directly “coupled,” “linked,” or “connected” to each other, or there may be intervening elements therebetween through which the element may be “coupled,” “linked,” or “connected” to the other element. Furthermore, when a component is referred to as being “electrically coupled” to another component, the component may be directly connected to the other component, or there may be intervening components therebetween such that the component and the other component are indirectly connected to each other.

[0053] Throughout this specification, unless otherwise specified, when "A and / or B" is stated, it means A, B, or A and B. That is, "and / or" includes any or all combinations of the listed items. Unless otherwise specified, when "C to D" is stated, it means C or more and D or less.

[0054] A secondary battery may include an electrode assembly and an outer body housing the electrode assembly, the electrode assembly including a positive electrode plate, a separator, and a negative electrode plate. The outer body may be categorized into a circular type, a prismatic type, and a pouch type according to its shape.

[0055] Pouch-type secondary batteries can include a lightweight laminated pouch that is easily deformable into various shapes, and can further include a protective circuit module mounted on one side of the pouch to control the charging and discharging of the battery. During the manufacture of the electrode assembly, the slurry for the electrode mixture layer can be applied to the electrode current collector and then dried. However, the slurry may flow downward, resulting in a sliding area at at least one end of the electrode assembly where the electrode active material layer has a small thickness.

[0056] Figure 1 is a perspective view of a secondary battery according to an embodiment of the present disclosure, and Figure 2 is an exploded perspective view of a secondary battery according to an embodiment of the present disclosure.

[0057] refer to Figure 1 and Figure 2 , a secondary battery 100 according to an embodiment of the present disclosure may include an electrode assembly 110 and a case 120 . The electrode assembly 110 may be accommodated in the case 120 .

[0058] The electrode assembly 110 can be formed by winding or stacking a stack of the first electrode plate 111, the separator 113, and the second electrode plate 112 into a thin sheet or film. When the electrode assembly 110 is a wound stack, a winding axis can be parallel to a longitudinal direction of the case 120. In other embodiments, the electrode assembly 110 can be a stacked type rather than a wound type, and the shape of the electrode assembly 110 is not limited in the present disclosure. Furthermore, the electrode assembly can be a Z-shaped stack electrode assembly in which positive and negative electrode plates are inserted to both sides of a separator and then bent into a Z-shaped stack. Furthermore, one or more electrode assemblies 110 can be stacked such that long edges of the electrode assemblies 110 are adjacent to each other and accommodated in the case, and the number of the electrode assemblies 110 in the case is not limited in the present disclosure. The first electrode plate 111 of the electrode assembly 110 can serve as a positive electrode, and the second electrode plate 112 can serve as a negative electrode. Of course, the reverse is also possible.

[0059] The first electrode plate 111 can be formed by applying a first electrode active material such as graphite or carbon to a first electrode current collector formed of a metal foil such as copper, a copper alloy, nickel, or a nickel alloy. The first electrode plate 111 can include a first electrode tab (e.g., a first uncoated portion) that is a region to which the first electrode active material is not applied.

[0060] The first electrode active material can be a negative electrode active material. The negative electrode active material can include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and undoping lithium, or a transition metal oxide.

[0061] The material capable of reversibly intercalating / deintercalating lithium ions can be a carbon-based negative electrode active material, which can include, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon can include graphite such as natural graphite or artificial graphite, and examples of the amorphous carbon can include soft carbon, hard carbon, pitch carbide, meso-phase pitch carbide, sintered coke, etc.

[0062] The Si-based negative electrode active material or the Sn-based negative electrode active material can be used as a material capable of doping and undoping lithium. The Si-based negative electrode active material can be silicon, a silicon-carbon composite, SiO x (0 < x < 2), a Si-based alloy, or a combination thereof.

[0063] The silicon-carbon composite can be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite can be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles.

[0064] The silicon-carbon composite can further include crystalline carbon. For example, the silicon-carbon composite can include a core including crystalline carbon and silicon particles and an amorphous carbon coating layer on the surface of the core.

[0065] A negative electrode for a lithium secondary battery can include a current collector and a negative electrode active material layer disposed on the current collector. The negative electrode active material layer can include a negative electrode active material, and can further include a binder and / or a conductive material.

[0066] For example, the negative electrode active material layer can include about 90 wt% to about 99 wt% of a negative electrode active material, about 0.5 wt% to about 5 wt% of a binder, and about 0 wt% to about 5 wt% of a conductive material.

[0067] A non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof can be used as the binder. When an aqueous binder is used as the negative electrode binder, a cellulose-based compound capable of imparting adhesiveness can be further included.

[0068] As the negative electrode current collector, one selected from a copper foil, a nickel foil, a stainless steel foil, a titanium foil, a nickel foam, a copper foam, a polymer substrate coated with a conductive metal, and a combination thereof can be used.

[0069] In some embodiments, the first electrode tab 111a can be formed by being cut in advance to protrude to one side of the electrode assembly 110 when the first electrode plate 111 is manufactured, or the first electrode plate 111 can protrude more (e.g., protrude far or protrude more than the separator 113) to one side of the electrode assembly 110 without being separately cut. The first lead tab 114 of the external terminal can be welded to the first electrode tab 111a of the first electrode plate 111 to be electrically connected to the outside. In some examples, one end of the first lead tab 114 can be connected to the first electrode tab 111a to be electrically connected to the first electrode plate 111. The other end of the first lead tab 114 can protrude and extend to the outside of the electrode assembly 110. An insulating member 114a can be attached to the first lead tab 114. The insulating member 114a can be a tab film for insulation. The insulating member 114a can prevent a short circuit between the case 120 and the first lead tab 114.

[0070] The second electrode plate 112 can be formed by applying a second electrode active material such as a transition metal oxide on a second electrode current collector formed of a metal foil such as aluminum or an aluminum alloy. The second electrode plate 112 can include a second electrode tab (e.g., a second uncoated portion) that is a region to which the second electrode active material is not applied.

[0071] The second electrode active material can be a positive electrode active material. A compound capable of reversibly intercalating and deintercalating lithium (lithiated intercalation compound) can be used as the positive electrode active material. In some embodiments, one or more of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and a combination thereof can be used.

[0072] The complex oxide can be a lithium transition metal complex oxide, and examples thereof can include a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium manganese-based oxide, a lithium iron phosphate-based compound, a cobalt-free nickel manganese-based oxide, or a combination thereof.

[0073] As an example, a compound represented by any one of the following molecular formulas can be used: Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b- c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g Gg PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); and Li a FePO4(0.90≤a≤1.8).

[0074] In the above formula: A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; and L1 is Mn, Al, or a combination thereof.

[0075] A positive electrode for a lithium secondary battery can include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer can include a positive electrode active material, and can further include a binder and / or a conductive material.

[0076] The content of the positive electrode active material is in the range of about 90 wt% to about 99.5 wt% based on 100 wt% of the positive electrode active material layer, and the content of the binder and the conductive material is in the range of about 0.5 wt% to about 5 wt% based on 100 wt% of the positive electrode active material layer, respectively.

[0077] The current collector can be aluminum (Al), but is not limited thereto.

[0078] In some examples, the second electrode tab 112a can be formed by being cut in advance to protrude in one direction when the second electrode plate 112 is manufactured, or can be formed to protrude farther than the separator 113 in one direction without a separate cutting process. The second lead tab 115 of the external terminal can be welded to the second electrode tab 112a of the second electrode plate 112 to be electrically connected to the outside. In some examples, one end of the second lead tab 115 can be connected to the second electrode tab 112a to be electrically connected to the second electrode plate 112. The other end of the second lead tab 115 can protrude and extend to the outside of the electrode assembly 110. An insulating member 115a can be attached to the second lead tab 115. The insulating member 115a can be a tab film for insulation. The insulating member 115a can prevent a short circuit between the case 120 and the second lead tab 115.

[0079] In some examples, the first lead tab 114 can be located on the upper left surface of the electrode assembly 110, and the second lead tab 115 can be located on the upper right surface of the electrode assembly 110. The first lead tab 114 and the second lead tab 115 can be located on one surface facing the same direction. In such an embodiment, for ease of description, it can be based on the first lead tab 114 and the second lead tab 115 being located on the upper surface of the electrode assembly 110.Figure 3 The left and right sides are defined, and if the electrode assembly 110 is rotated left and right or up and down, its position may be changed.

[0080] The separator 113 may be located between the first electrode plate 111 and the second electrode plate 112 to prevent a short circuit therebetween while allowing lithium ions to move between them. For example, the separator 113 may include polyethylene, polypropylene, or a composite film of polyethylene and polypropylene. Depending on the type of lithium secondary battery, the separator 113 may be present between the first electrode plate 111 (e.g., the negative electrode) and the second electrode plate 112 (e.g., the positive electrode).

[0081] Polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more layers thereof may be used as the separator 113. The separator 113 may include a porous substrate and a coating layer containing an organic material, an inorganic material, or a combination thereof on one or both surfaces of the porous substrate.

[0082] The organic material may include polyvinylidene fluoride heavy antibodies or (meth) acrylic polymers. The inorganic material may include 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, but is not limited thereto. The organic material and the inorganic material may be mixed in one coating, or may be in the form of a coating comprising an organic material and a coating comprising an inorganic material laminated to each other.

[0083] The electrode assembly 110 may be substantially housed in the housing 120 together with the electrolyte. The electrolyte may be in the form of liquid, solid, or gel. The electrolyte for a lithium secondary battery may include a non-aqueous organic solvent and a lithium salt.

[0084] The non-aqueous organic solvent is used as a medium through which the ions participating in the electrochemical reaction of the battery can move. The non-aqueous organic solvent can be a carbonate, ester, ether, ketone, alcohol solvent, or an aprotic solvent, and can be used alone or in combination of two or more. In addition, when a carbonate solvent is used, a mixture of a cyclic carbonate and a chain carbonate can be used.

[0085] The case 120 can provide a space to accommodate the electrode assembly 110, and can be formed in various shapes, such as a pouch type, a prismatic type, or a cylindrical type. In some examples, the pouch type case 120 will be described as one embodiment. In a state of accommodating the electrode assembly 110, the case 120 can be sealed in a manner in which the sealing portions 124 on the edges thereof are surrounded by each other. In such an embodiment, sealing can be achieved with a tab film provided between the sealing portions 124. The sealing portions 124 of the case 120 can be made of a hot melt material, and the hot melt layers can be adhered to each other to seal the case 120. Since the hot melt material generally has weak adhesion to metal, the tab film in the form of a thin film can be attached to the tabs and fused to the case 120. The case 120 can include a first pouch film 121 to accommodate the electrode assembly 110, and a second pouch film 122 coupled to the first pouch film 121. The overall rectangular pouch film can be folded along the center thereof in a longitudinal direction to divide the case 120 into the first pouch film 121 and the second pouch film 122. In some examples, a receiving recess 123 to receive the electrode assembly 110 can be formed in the first pouch film 121 by press working or the like, and a sealing portion 124 to be sealed with the second pouch film 122 can be formed on the first pouch film 121. The first lead tab 114 and the second lead tab 115 can protrude to the outside of the case 120 through the sealing portion 124. In such an embodiment, the insulating members 114a and 115a attached to the first lead tab 114 and the second lead tab 115 can be in contact with the sealing portion 124.

[0086] In some examples, a tape can be attached to the electrode assembly 110 during a hot press charging (HPC) process, which is a process of hot pressing and charging a polymer monomer, to increase the adhesion of the negative electrode sliding portion. However, if the body tape is attached to the sliding region first before being attached to other regions, the insertability of the electrode assembly can be deteriorated, and monomer top adhesion control dispersion can occur. The sliding region can be a region in which slurry flows downward, and thus the thickness of the electrode active material layer is reduced.

[0087] Accordingly, in an embodiment, an upper body tape can be employed to supplement (e.g., compensate for) the negative electrode sliding portion, and a process of attaching the upper body tape can be performed in the last stage, so that the insertability of the electrode assembly can be improved, and the thermal exposure / dripping characteristics thereof can be improved. Furthermore, due to the use of the body tape, the adhesion of the upper end portion of the battery monomer can be increased, and the thickness balance between the upper end portion, the middle portion, and the lower end portion of the battery monomer can be secured, so that the quality of the battery monomer is significantly improved.

[0088] Hereinafter, the tape attachment process will be described in more detail.

[0089] Figure 3is a plan view of an electrode assembly according to an embodiment of the disclosure, Figure 4 is a diagram schematically illustrating a procedure for attaching a tape according to an embodiment of the disclosure, and Figure 5 is a plan view for explaining a tape attaching process according to an embodiment of the disclosure.

[0090] Referring to Figure 3 , the electrode assembly 110 can include a top tape 117 attached to an upper end portion thereof, a bottom tape 118 attached to an upper end portion thereof to surround a lower end portion thereof, a main tape 119 attached to an upper surface of the top tape 117 while surrounding an upper end portion thereof, and a side tape 116 attached to an upper end portion thereof to surround at least one of side end portions thereof. In such an embodiment, the upper end portion of the electrode assembly 110 can include a sliding region in which the thicknesses of the first and second electrode active material layers are reduced, i.e., the thicknesses of the first and second electrode active material layers in the sliding region are less than the thicknesses in other regions.

[0091] In some examples, the side tape 116 can be attached to the electrode assembly 110 to surround, for example, wrap, each of two side end portions of the electrode assembly 110 in a longitudinal direction. For example, referring to Figure 3 , the side tape 116 can extend perpendicular to the main tape 119 (e.g., longitudinally) to cover lateral sides of the electrode assembly 110.

[0092] In some examples, the bottom tape 118 can be attached to the electrode assembly 110 to surround, for example, wrap, a lower end portion of the electrode assembly 110. For example, referring to Figure 3 , the bottom tape 118 and the top tape 117 can be at opposite ends of the electrode assembly 110.

[0093] In some examples, the top tape 117 can be attached between the first and second electrode tabs 111a and 112a. In some examples, the top tape 117 can be attached between the first and second lead tabs 114 and 115. In other embodiments, the top tape 117 can be attached around a pair of long side surfaces of an upper surface of the electrode assembly 110 and side surfaces of the electrode assembly 110 connected to the upper surface of the electrode assembly 110. For example, referring to Figure 3 , the top tape 117 can be attached to a surface of the electrode assembly 110 through which the first and second electrode tabs 111a and 112a extend.

[0094] In some examples, the main tape 119 can be attached around an uppermost layer of the electrode assembly 110. In other embodiments, the main tape 119 can be attached to the electrode assembly 110 to overlap at least a portion of the top tape 117 and at least a portion of the side tape 116. For example, referring to Figure 3The body tape 119 can cover (e.g., overlap) an upper end portion of the electrode assembly 110 (e.g., including covering the top tape 117 entirely).

[0095] The tape attachment process will be described hereinafter with reference to Figure 4 and Figure 5 The tape attachment process will be described hereinafter with reference to Figure 4 and Figure 5 First, the electrode assembly 110 including the first electrode plate 111, the second electrode plate 112, and the separator 113 interposed between the first electrode plate 111 and the second electrode plate 112 can be prepared. In such an embodiment, the electrode assembly 110 can be implemented in a stacked form.

[0096] Referring to Figure 5 The first electrode plate 111 can include a first electrode current collector, a first electrode active material layer 111c coated on the first electrode current collector, a first electrode uncoated portion 111b adjacent to the first electrode active material layer 111c at an end portion of the first electrode current collector (i.e., the first electrode uncoated portion 111b can be an uncoated exposed edge of the first electrode current collector), and a first electrode tab 111a provided at an end portion of the first electrode uncoated portion 111b. The structure of the second electrode plate 112 can be substantially the same as that of the first electrode plate 111. During the manufacturing of the electrode assembly 110, the slurry for the electrode active material layer coated on the electrode current collector can flow downward (i.e., from the top of the electrode assembly 110 adjacent to the first electrode tab 111a and the second electrode tab 112a toward the bottom of the electrode assembly 110 opposite to the top of the electrode assembly 110) during drying, thereby defining a slide region at the top of the electrode assembly 110. In other words, due to the flow of the slurry for the electrode active material layer from the top to the bottom of the electrode assembly 110, the dried amount (e.g., thickness) of the electrode active material layer on the electrode current collector at the top of the electrode assembly 110 can decrease (e.g., be smaller) compared to the amount (e.g., thickness) of the electrode active material layer on the electrode current collector at the middle and bottom of the electrode assembly 110. For example, referring to Figure 5 The slide region at the top of the electrode assembly 110 can refer to a top region of the electrode active material layer 111c. In some examples, preparing the electrode assembly 110 can include forming the slide region in the upper end portion of the electrode assembly 110 such that the thickness of the first electrode active material layer 111c and the second electrode active material layer in the slide region is less than the thickness in other regions.

[0097] In some examples, a top strap 117 can be attached to an upper end portion of the electrode assembly 110 (top paste). In some examples, as described above, the top strap 117 can be attached between the first electrode tab 111a and the second electrode tab 112a. In other embodiments, the top strap 117 can be attached around a pair of long side surfaces (i.e., major surfaces) of an upper surface of the electrode assembly 110 and side surfaces of the electrode assembly 110 that are connected to the upper surface of the electrode assembly 110. In some examples, the top strap 117 can be attached to wrap around, for example, an edge of the electrode assembly 110 in a direction in which the first electrode tab 111a and the second electrode tab 112a exit. In some examples, the top strap 117 can be attached to secure a portion of the separator 113 that protrudes outward beyond the first electrode plate 111 and the second electrode plate 112 from the upper end portion of the electrode assembly 110. For example, referring to Figure 5 , the top strap 117 can be attached to (e.g., directly contact) both major overlapping surfaces of the electrode assembly 110 such that the top strap 117 can extend longitudinally from one major surface of the electrode assembly 110 to another major surface of the electrode assembly 110 while wrapping around the surfaces through which the first electrode tab 111a and the second electrode tab 112a extend.

[0098] Subsequently, in some examples, a bottom strap 118 can be attached to a lower end portion of the electrode assembly 110 to wrap around the lower end portion of the electrode assembly 110 (BTM paste). For example, referring to Figure 5 , the bottom strap 118 can extend longitudinally along a surface of the electrode assembly 110 opposite the first electrode tab 111a and the second electrode tab 112a, and the bottom strap 118 can be attached to (e.g., directly contact) both major overlapping surfaces of the electrode assembly 110.

[0099] Subsequently, in some examples, the body tape 119 can be attached to the upper end portion of the electrode assembly 110 to wrap around, for example, the upper end portion of the electrode assembly 110 (body taping). In some examples, the body tape 119 can be attached around the uppermost outer layer of the electrode assembly 110, for example, the body tape 119 can wrap around the entire outer circumference of the electrode assembly 110 at the upper end portion of the electrode assembly 110 (i.e., the portion from which the first and second electrode tabs 111a and 112a protrude). In some examples, the body tape 119 can be attached to the top tape 117 such that at least a portion of the top tape 117 is between the body tape 119 and the major surface of the electrode assembly 110. In other embodiments, the body tape 119 can be attached to the top tape 117 to overlap at least a portion of the top tape 117, for example, the body tape 119 can cover the entire top tape 117. For example, the length of the body tape 119 in the longitudinal direction of the electrode assembly 110 (e.g., along the direction of the imaginary line connecting the top tape 117 and the bottom tape 118) can be about 14% to about 16% of the length of the electrode assembly 110 in the longitudinal direction. For example, the length of overlap between the body tape 119 and the major surface of the electrode assembly 110 can be about 14% to about 16% of the length of the electrode assembly 110 in the longitudinal direction (e.g., thus the length of the body tape 119 can be measured along the major surface of the electrode assembly 110). For example, the length of the body tape 119 in the longitudinal direction of the electrode assembly 110 can completely cover at least the top portion of the active material layer (i.e., the sliding region) and the electrode uncoated portion, such that the body tape 119 can compensate for (e.g., supplement) the reduced thickness of the active material layer in the top portion of the electrode assembly 110.

[0100] In some examples, the side tape 116 can be attached to at least one of the side end portions of the electrode assembly 110 (side taping) prior to attaching the top tape 117. In this case, the body tape 119 can be attached to overlap at least a portion of the side tape 116 (e.g., thus at least a portion of the side tape 116 can be between the body tape 119 and the major surface of the electrode assembly 110).

[0101] In other embodiments, the side tape 116 can be attached to at least one of the side end portions of the electrode assembly 110 (side taping) after attaching the body tape 119. In this case, the side tape 116 can be attached to overlap at least a portion of the body tape 119 (e.g., thus at least a portion of the body tape 119 can be between the side tape 116 and the major surface of the electrode assembly 110).

[0102] In some examples, the top tape 117, the main body tape 119, the bottom tape 118, and / or the side tape 116 can be formed by applying an adhesive to a synthetic resin selected from polyethylene terephthalate (PET), polypropylene (PP), and polyimide (PI), none of which reacts with an electrolyte.

[0103] In some examples, after the above-described taping process is completed, the electrode assembly 110 can be inserted into the case 120.

[0104] Hereinafter, the effects of the embodiments will be described with reference to Figure 5 The effects of the embodiments are described through comparison between the examples and the comparative examples. Figures 6A-10 FIG. 1 is a plan view showing a comparative example of an electrode assembly. Figures 6A-6C FIG. 2 is a heat map showing results of measuring flatness of the embodiments and the comparative examples. Figure 7 FIG. 3 is a data table showing results of checking thickness balance between parts of a battery cell according to the embodiments and the comparative examples. Figure 8 FIG. 4 is a graph and a table illustrating results of evaluating a thermal exposure limit of the embodiments and the comparative examples. Figures 9A-9E FIG. 5 is a graph showing a short circuit point and a deconstruction analysis of the comparative example based on the thermal exposure limit evaluation.

[0105] Figure 10 FIG. 1 is a plan view showing a comparative example of an electrode assembly.

[0106] Figure 6A FIG. 1 is a plan view showing a comparative example of an electrode assembly.

[0107] Figure 6B is a schematic view of Comparative Example 3 corresponding to the battery cell 410 provided with the body tape 417 without the top tape. The battery cell 410 can include the side tape 416, the body tape 417, and the bottom tape 418. Since the first electrode plate 411, the second electrode plate 412, the separator 413, the first electrode tab 411a, the second electrode tab 412a, the first lead tab 414, the second lead tab 415, and the insulating members 414a and 415a of Comparative Example 3 have the same structure as that of the embodiment, a description thereof will be omitted.

[0108] Figure 6C is a heat map of the results of measuring the flatness for the comparative examples and the embodiment. Figure 7 Part (a) of shows the results of measuring the flatness of Comparative Example 1 provided with the step tape 219 having a thickness of about 60 µm without a separate body tape. Figure 7 Part (b) of shows the results of measuring the flatness of Comparative Example 3 provided with the body tape 417 having a thickness of about 56 µm without the top tape. Figure 7 Part (c) of shows the results of measuring the flatness of the embodiment of the present disclosure provided with the body tape 119 having a thickness of about 30 µm without the step tape.

[0109] Figure 7 Each of parts (a) to (c) of shows the portion indicated by the dotted rectangle in each of parts (a) to (c) represents the position of the upper end portion of the battery cell (i.e., the upper end portion of the electrode assembly 110). It can be seen that the electrode assembly according to the embodiment of the present disclosure (i.e., Figure 7 Part (c) of shows the color of the heat map of the electrode assembly according to the embodiment of the present disclosure (i.e., Figure 7 Parts (a) and (b) of shows the color of the heat map of the electrode assembly according to the embodiment of the present disclosure (i.e.,

[0110] In Figure 7 , (a) to (e) respectively represent the results of measuring the thickness of the upper end portion, the middle portion, and the lower end portion in Comparative Example 1, Comparative Example 2 provided with the body tape 317 having a thickness of about 56 µm, Comparative Example 3 provided with the body tape 417 having a thickness of about 56 µm, Comparative Example 2 provided with the body tape 317 having a thickness of about 30 µm, and the embodiment of the present disclosure provided with the body tape 119 having a thickness of about 30 µm.

[0111] Referring to Figure 8 , it can be seen that the thickness balance between the upper end portion, the middle portion, and the lower end portion in the electrode assembly of Comparative Example 2, Comparative Example 3, and the embodiment each provided with the body tape is improved compared to Comparative Example 1 not provided with the body tape.

[0112] Figure 8is a graph indicating the results of evaluating the heat exposure limit when the heating temperature reaches about 132 degrees Celsius (°C) at a rate of 7 degrees Celsius (°C) / min, and Figures 9A-9D is an open-circuit voltage (OCV) data table. Figure 9E and Figure 9A (a) in corresponds to Comparative Example 1, and Figure 9E and Figure 9B (b) in corresponds to Comparative Example 2 provided with a main band 317 having a thickness of about 56 µm. Figure 9E and Figure 9C (c) in corresponds to Comparative Example 3 provided with a main band 417 having a thickness of about 56 µm, and Figure 9E and Figure 9D (d) in corresponds to the embodiment provided with a main band 119 having a thickness of about 30 µm.

[0113] Referring to the portion indicated by the dotted rectangle in Figure 9E and the results shown in Figures 9A-9D it can be seen that, during the process in which the heating temperature reaches and remains at about 132 degrees Celsius (°C), Figure 9E and Figure 9D (d) in the OCV values of the embodiments shown have an average value (Avg.) of 0.769 and a standard deviation (Stdev.) of 0.167, i.e., the OCV drop at the end of the process is stable.

[0114] Figure 9E is a graph showing short-circuit points and deconstruction analysis when the comparative examples were exposed to heat of 132 degrees Celsius (°C). From (a) in Figure 10 corresponding to Comparative Example 1, it can be seen that the upper end portion and the lower end portion of the negative electrode were severely oxidized. From (b) in Figure 10 corresponding to Comparative Example 2 provided with a main band 317 having a thickness of about 56 µm, it can be seen that the inner lower portion was oxidized. From (c) in Figure 10 corresponding to Comparative Example 3 having a main band 417 having a thickness of about 56 µm, it can be seen that the upper end portion of the negative electrode was oxidized.

[0115] Figure 10 is a graph schematically showing a smart phone equipped with a secondary battery according to an embodiment of the present disclosure. As Figure 11As illustrated, the secondary battery 10 according to the above-described embodiment of the disclosure can be a small battery installed in a small portable device such as a smart phone 1000. In this case, since the exemplary secondary battery 10 is configured to be able to increase its capacity while having a slim internal structure, the above-described secondary battery 10 can be a battery suitable for application to a small portable device. As used herein, the terms "secondary battery" and "battery" have the same meaning and are only different in expression for the convenience of description. The secondary battery according to the above-described embodiment can increase the size for manufacturing a battery pack.

[0116] Figure 11 and Figure 12A A perspective view of an example of an exemplary battery pack 30. The battery pack 30 can include a plurality of battery modules 20 and a housing 31 for accommodating the plurality of battery modules 20. For example, the housing 31 can include a first housing 31-1 and a second housing 31-2 coupled in opposite directions through the plurality of battery modules 20. The plurality of battery modules 20 can be electrically connected to each other by using a busbar 25-1, and the plurality of battery modules 20 can be electrically connected to each other in a series / parallel or series-parallel hybrid method, thereby obtaining a desired (e.g., required) electrical output.

[0117] Figure 12B and Figure 13A A perspective view and a side view of an example of an exemplary vehicle body 40 and vehicle components. In Figure 13B , the battery pack 30 can include a first housing 31-1 (i.e., a battery pack cover) that is a part of a vehicle body floor 41 and a second housing 31-2 (i.e., a battery pack frame) disposed under the vehicle body floor 41. The second housing 31-2 and the first housing 31-1 can be integrally formed with a vehicle floor 42. The vehicle body floor 41 separates the inside and outside of the vehicle, and the second housing 31-2 can be disposed outside the vehicle.

[0118] Referring to Figure 13A Figure 13B , a vehicle 50 can be formed by incorporating additional components such as a hood 51 in front of the vehicle and fenders 52 located in front and rear of the vehicle body 40, respectively. The vehicle 50 can include a battery pack 30 including a first housing 31-1 (i.e., a battery pack cover) and a second housing 31-2 (i.e., a battery pack frame), and the battery pack 30 can be coupled to the vehicle body 40.

[0119] As is apparent from the above description, according to the disclosure, it is possible to provide a secondary battery and a method of manufacturing a secondary battery in which a main body tape is attached to an electrode assembly to supplement a sliding area of the electrode assembly, so that adhesion of an upper end portion of the electrode assembly can be increased, and thickness balance between an upper end portion, a middle portion, and a lower end portion of a battery cell (i.e., the electrode assembly) can be secured, thereby improving the quality of the battery cell.

[0120] While the disclosure has been described with reference to embodiments and illustrative diagrams that exemplify aspects thereof, the disclosure is not limited thereto. Various modifications and variations can be made by those skilled in the art of the disclosure within the technical spirit of the disclosure and claims and equivalents thereof.

[0121] Example embodiments have been disclosed herein and, although the use of particular terms in this specification and the claims are intended to be interpreted under a broad and liberally usage of the term, it is to be understood that all equivalents, no matter how obvious in which they are deferred by others, are intended to be considered equivalents of the specific embodiment disclosed. In some instances, well-known methods, structures and techniques have not been described in detail in order to avoid obscuring the application. Also, the examples provided are intended to be illustrative only and are presented merely to more clearly and fully describe the disclosed subject matter. It is not intended that the application or the patent claims be limited to the specific examples presented.

Claims

1. A method of manufacturing a secondary battery, the method comprising: preparing an electrode assembly including a first electrode plate, a second electrode plate, and a separator between the first electrode plate and the second electrode plate; attaching a top tape to an upper end portion of the electrode assembly; attaching a bottom tape to a lower end portion of the electrode assembly, the bottom tape surrounding the lower end portion of the electrode assembly; attaching a body tape to the upper end portion of the electrode assembly, the body tape surrounding the upper end portion of the electrode assembly; and inserting the electrode assembly into a case, wherein the first electrode plate includes a first electrode current collector, a first electrode active material layer on the first electrode current collector, a first electrode uncoated portion adjacent to the first electrode active material layer at an end of the first electrode current collector, and a first electrode tab at an end portion of the first electrode uncoated portion, and wherein the second electrode plate includes a second electrode current collector, a second electrode active material layer on the second electrode current collector, a second electrode uncoated portion adjacent to the second electrode active material layer at an end of the second electrode current collector, and a second electrode tab at an end portion of the second electrode uncoated portion.

2. The method of claim 1, wherein preparing the electrode assembly includes forming a sliding region in the upper end portion of the electrode assembly such that a thickness of the first electrode active material layer and the second electrode active material layer in the sliding region is less than a thickness in other regions.

3. The method of claim 1, wherein attaching the body tape includes attaching the body tape around an uppermost layer of the electrode assembly.

4. The method of claim 1, wherein attaching the body tape includes attaching the body tape to the top tape such that at least a portion of the top tape is between the body tape and a major surface of the electrode assembly.

5. The method of claim 1, wherein attaching the top tape includes attaching the top tape between the first electrode tab and the second electrode tab.

6. The method of claim 1, wherein attaching the top tape includes attaching the top tape around an upper surface of the electrode assembly, the top tape in contact with a pair of major surfaces of the electrode assembly connected to the upper surface of the electrode assembly.

7. The method of claim 1, further comprising attaching a side tape to at least one of the side end portions of the electrode assembly prior to attaching the top tape.

8. The method of claim 7, wherein attaching the body tape includes attaching the body tape to overlap at least a portion of the side tape such that the at least a portion of the side tape is between the body tape and a major surface of the electrode assembly.

9. The method of claim 1, further comprising attaching a side tape to at least one of the side end portions of the electrode assembly after attaching the body tape. 10.The method of claim 9, wherein attaching the side tape comprises attaching the side tape to overlap at least a portion of the body tape such that the at least a portion of the body tape is between the side tape and a major surface of the electrode assembly. 11.The method of claim 1, wherein attaching the top tape comprises attaching the top tape to surround edges of the electrode assembly in a lead-out direction of the first and second electrode tabs. 12.The method of claim 1, wherein attaching the top tape comprises attaching the top tape to secure a portion of the separator that protrudes outward beyond the first and second electrode plates from the upper end portion of the electrode assembly. 13.The method of claim 1, wherein the body tape has a length that is 14-16% of a length of the electrode assembly in a longitudinal direction of the electrode assembly. 14.The method of claim 1, wherein the top tape, the body tape, and / or the bottom tape are formed by applying an adhesive to a synthetic resin selected from polyethylene terephthalate, polypropylene, and polyimide. 15.A secondary battery comprising: an electrode assembly including a first electrode plate, a second electrode plate, and a separator between the first and second electrode plates; a top tape attached to an upper end portion of the electrode assembly; a bottom tape surrounding a lower end portion of the electrode assembly; a body tape attached to the top tape and surrounding the upper end portion of the electrode assembly; a side tape attached to the electrode assembly and surrounding at least one of side end portions of the electrode assembly; and a case housing the electrode assembly, the case including a sealing portion along an edge portion thereof, wherein the first electrode plate includes a first electrode current collector, a first electrode active material layer on the first electrode current collector, a first electrode uncoated portion adjacent to the first electrode active material layer at an end portion of the first electrode current collector, and a first electrode tab at an end portion of the first electrode uncoated portion, and wherein the second electrode plate includes a second electrode current collector, a second electrode active material layer on the second electrode current collector, a second electrode uncoated portion adjacent to the second electrode active material layer at an end portion of the second electrode current collector, and a second electrode tab at an end portion of the second electrode uncoated portion. 16.The secondary battery of claim 15, wherein the upper end portion of the electrode assembly includes a sliding region in which the first and second electrode active material layers have a thickness that is less than a thickness in other regions. 17.The secondary battery of claim 15, wherein the body tape is attached around an uppermost outer layer of the electrode assembly. 18.The secondary battery of claim 15, wherein the top tape is attached between the first and second electrode tabs. ​ 19. The secondary battery of claim 15, wherein the top strap is attached around an upper surface of the electrode assembly and a pair of long side surfaces of the electrode assembly that are connected to the upper surface of the electrode assembly.

20. The secondary battery of claim 15, wherein the main body strap overlaps at least a portion of the top strap and at least a portion of the side straps.

Images