Electronic component and secondary battery including the same

Abstract

An electrode assembly includes a negative electrode plate including a negative electrode current collector and a negative electrode active material layer on a portion of each of opposite surfaces of the negative electrode current collector, a positive electrode plate, and a separator between the negative electrode plate and the positive electrode plate, the positive electrode plate includes a positive electrode current collector and a positive electrode active material layer on a portion of each of opposite surfaces of the positive electrode current collector, in which the negative electrode plate, the positive electrode plate, and the separator are wound to form a plurality of bending regions, and the negative electrode active material layer and the positive electrode active material layer are aligned based on a position of a trailing edge of a leading edge bending region of the plurality of bending regions of the negative electrode plate and the positive electrode plate.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit from Korean Patent Application No. 10-2024-0111144, filed with the Korean Intellectual Property Office on August 20, 2024, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] Embodiments of this disclosure relate to an electrode assembly and a secondary battery including the electrode assembly. Background Technology

[0004] Unlike primary batteries, which are not designed to be (re)chargeable, secondary (or rechargeable) batteries are designed to be both discharged and recharged. Low-capacity secondary batteries are used in portable small electronic devices such as smartphones, feature phones, laptops, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources to drive motors in hybrid and electric vehicles, as well as for storing electricity (e.g., household and / or utility-scale power storage). A secondary battery typically includes an electrode assembly containing positive and negative electrodes, a housing that houses the electrode assembly, and electrode terminals connected to the electrode assembly.

[0005] During repeated charge-discharge cycles, the electrode thickness of the electrode assembly may increase during charging and decrease during discharging. Cycling allows for the evaluation of the long-term performance and stability of the secondary battery, providing valuable data for optimizing its design and materials.

[0006] The information disclosed in this background section is intended to enhance understanding of the background of this disclosure, and therefore may contain information that does not constitute related (or prior art). Summary of the Invention

[0007] One aspect of the embodiment provides an electrode assembly comprising: a negative electrode plate including a negative electrode current collector and a negative electrode active material layer on a portion of each of the opposite surfaces of the negative electrode current collector; a positive electrode plate including a positive electrode current collector and a positive electrode active material layer on a portion of each of the opposite surfaces of the positive electrode current collector; and a diaphragm between the negative electrode plate and the positive electrode plate, wherein the negative electrode plate, the positive electrode plate, and the diaphragm are wound together to form a plurality of curved regions, and the negative electrode active material layer and the positive electrode active material layer are aligned based on the position of the trailing edge of a leading edge curved region among the plurality of curved regions of the negative electrode plate and the positive electrode plate.

[0008] In some examples, the negative electrode active material layer may extend into the region between the trailing edge of one of the leading edge bends and the leading edge of another of the leading edge bends.

[0009] In some examples, the negative electrode active material layer can extend to a distance of 1 mm to 2 mm from the trailing edge of the bend in the leading edge of the coil.

[0010] In some examples, the positive electrode active material layer can be aligned with one of the trailing edges of the leading edge bend region.

[0011] In some examples, the negative electrode current collector of the negative electrode plate may have a first negative electrode surface and a second negative electrode surface opposite to the first negative electrode surface, and the negative electrode active material layer includes a first negative electrode active material layer on the first negative electrode surface and a second negative electrode active material layer on the second negative electrode surface; and the positive electrode current collector of the positive electrode plate may have a first positive electrode surface and a second positive electrode surface opposite to the first positive electrode surface, and the positive electrode active material layer includes a first positive electrode active material layer on the first positive electrode surface and a second positive electrode active material layer on the second positive electrode surface.

[0012] In some examples, the uncoated portions of the first and second negative electrodes, neither of which are coated with the first negative electrode active material layer, can be located at the leading edge and trailing edge of the first negative electrode surface, respectively. Similarly, the uncoated portions of the third and fourth negative electrodes, neither of which are coated with the second negative electrode active material layer, can be located at the leading edge and trailing edge of the second negative electrode surface, respectively.

[0013] In some examples, the negative electrode plate and the positive electrode plate can be arranged such that the first negative electrode surface and the second positive electrode surface face each other.

[0014] In some examples, the first negative electrode terminal and the second negative electrode terminal can be located at the uncoated portions of the third and fourth negative electrodes, respectively.

[0015] In some examples, the first negative electrode active material layer may begin between one of the trailing edges of the leading edge bend region and the leading edge of one of the leading edge bend regions.

[0016] In some examples, the first negative electrode active material layer may be within 1 mm to 2 mm of the trailing edge of the leading edge bend region.

[0017] In some examples, the area of ​​the first negative electrode active material layer can be larger than the area of ​​the second negative electrode active material layer.

[0018] In some examples, the uncoated portions of the first and second positive electrodes, neither of which are coated with the first positive electrode active material layer, can be located at the leading edge and trailing edge of the winding on the surface of the first positive electrode, respectively. Similarly, the uncoated portions of the third and fourth positive electrodes, neither of which are coated with the second positive electrode active material layer, can be located at the leading edge and trailing edge of the winding on the surface of the second positive electrode, respectively.

[0019] In some examples, the first positive electrode terminal and the second positive electrode terminal can be located at the uncoated portion of the first positive electrode and the uncoated portion of the second positive electrode, respectively.

[0020] In some examples, the second positive electrode active material layer may begin from one of the trailing edges of the leading edge bend region.

[0021] In some examples, the uncoated portion of the second positive electrode may be located on the outermost side of the electrode assembly and may be exposed to the outside while surrounding the outermost side of the electrode assembly.

[0022] In some examples, the area of ​​the second positive electrode active material layer can be larger than the area of ​​the first positive electrode active material layer.

[0023] In some examples, the first negative electrode active material layer may be aligned to protrude further than the second positive electrode active material layer in the direction toward the leading edge of the winding.

[0024] In some examples, the area of ​​the diaphragm can be larger than the area of ​​each of the positive and negative electrode plates.

[0025] In some examples, the area of ​​the positive electrode active material layer can be smaller than the area of ​​the negative electrode active material layer.

[0026] To achieve the above objectives, a secondary battery according to an embodiment of the present disclosure includes an electrode assembly and a housing having an internal space configured to house the electrode assembly within the internal space. Attached Figure Description

[0027] By referring to the detailed description of exemplary embodiments with reference to the accompanying drawings, those skilled in the art will clearly understand the features, wherein:

[0028] Figure 1 This is a perspective view of a secondary battery according to one embodiment;

[0029] Figure 2 This is a view showing the state of the electrode assembly of a secondary battery according to an embodiment of the present disclosure before winding;

[0030] Figure 3 This is a view showing the state of the electrode assembly of a secondary battery according to an embodiment of the present disclosure after winding;

[0031] Figure 4 This is a view showing the state of the electrode assembly of a secondary battery according to another embodiment of the present disclosure before winding;

[0032] Figure 5 This is a view showing the state of the electrode assembly of a secondary battery according to another embodiment of the present disclosure after winding;

[0033] Figure 6 This is a schematic view of a smartphone equipped with a secondary battery according to an embodiment of the present disclosure;

[0034] Figure 7A and 7B The illustration includes a perspective view of a battery pack of a secondary battery according to an embodiment of the present disclosure; and

[0035] Figure 8A and 8B The illustrations include perspective and side views of the body and vehicle components of a secondary battery according to embodiments of the present disclosure. Detailed Implementation

[0036] Exemplary embodiments will now be described more fully below with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be exhaustive and complete, and will fully illustrate exemplary implementations to those skilled in the art.

[0037] In the accompanying drawings, the dimensions of layers and regions may be exaggerated for clarity. It should also be understood that when a layer or element is referred to as being "on" another layer or substrate, it may be directly on the other layer or substrate, or there may be intermediate layers. Furthermore, it will be understood that when a layer is referred to as being "between" two layers, it may be the only layer between the two layers, or there may be one or more intermediate layers. The same reference numerals always refer to the same elements.

[0038] The terms or words used in this specification and claims should not be construed as limited to their ordinary or dictionary meanings, but should be interpreted in accordance with the principle that the inventor may be his / her own lexicographer to properly define the concepts of the terms in order to best interpret the exemplary embodiments, and are meant and understood to be consistent with the technical ideas of this disclosure.

[0039] The embodiments described in this specification and the configurations shown in the accompanying drawings are only some of the embodiments of this disclosure and do not represent all the technical concepts, aspects, and features of this disclosure. Therefore, it should be understood that various equivalents and modifications can replace or modify the embodiments described at the time of filing of this application.

[0040] It should be understood that when a component or layer is referred to as "connected to," "connected to," or "linked to" another component or layer, it can mean that it is connected to, linked to, or linked to another component or layer, or that one or more intermediate components or layers may exist. When a component or layer is referred to as "directly connected to," "directly connected to," or "directly linked to" another component or layer, no intermediate components or layers exist. For example, when a first component is described as "connected to" or "linked to" a second component, the first component can be directly connected to or linked to the second component, or the first component can be indirectly connected to or linked to the second component via one or more intermediate components.

[0041] As used herein, the term “and / or” includes any and all combinations of one or more items in the relevant list. Furthermore, the use of “may” in describing embodiments of this disclosure refers to “one or more embodiments of this disclosure.” When expressions such as “at least one” and “any one” appear before a list of elements, they modify the entire list of elements, not individual elements within that list. For example, when phrases 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 of A, B, and C,” or “at least one selected from A, B, and C” are used to specify a list of elements A, B, and C, the phrase may refer to any of A, B, and C, and all suitable combinations or subsets such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the terms “use,” “using,” and “used” can be considered synonymous with the terms “utilize,” “utilizing,” and “utilized.” As used herein, the terms “substantially,” “about,” etc., are used as approximate terms rather than terms of degree and are intended to take into account the inherent variations in measured or calculated values ​​that would be recognized by one of ordinary skill in the art.

[0042] It should be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Therefore, the first element, first component, first region, first layer, or first segment discussed below may be referred to as a second element, second component, second region, second layer, or second segment without departing from the teachings of the exemplary embodiments.

[0043] Spatial terms such as “below,” “under,” “down,” “above,” and “above” are used herein for convenience in describing the relationship of one element or feature shown in the accompanying drawings to other elements or features. It should be understood that these spatial terms are intended to cover different orientations in the use or operation of the device, other than those depicted in the accompanying drawings. For example, if the device in the accompanying drawings is flipped, an element described as “below” or “under” other elements or features would be oriented as “above” or “above” other elements or features. Therefore, the term “below” can encompass both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial descriptors used herein should be interpreted accordingly.

[0044] The specialized terminology used herein is for describing embodiments of this disclosure and is not intended to limit this disclosure. As used herein, the singular form “a (a and an)” is intended to include the plural form as well, unless the context clearly indicates otherwise. It should be further understood that when the terms “includes,” “including,” “comprises,” and / or “comprising” are used in this specification, they specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0045] Furthermore, any numerical range disclosed and / or referenced herein is intended to include said subranges that are included within the referenced range and have the same numerical precision. For example, the range “1.0 to 10.0” is intended to include all subranges between the referenced minimum value of 1.0 and the referenced maximum value of 10.0, i.e., the minimum value is equal to or greater than 1.0 and the maximum value is equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit referenced herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit referenced herein is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to amend this specification (including the claims) to expressly reference any subranges within the scope of this express reference. All such ranges are intended to include any subranges that may be expressly stated in modified form.

[0046] When two comparisons are described as "identical," it may mean that they are "substantially identical." Therefore, the phrase "substantially identical" can include cases with what is considered a low deviation in the field, such as 5% or less. Furthermore, when a parameter is described as uniform over a given region, it may mean that it is uniform in an average sense.

[0047] Throughout this specification, unless otherwise stated, each element may be singular or plural.

[0048] When any element is referred to as being "above (or below)" or "on (or below)" an assembly, it may mean that the element is positioned to contact the upper (or lower) surface of the assembly, and it may also mean that another assembly may be located between the assembly and any element that is set (or located or positioned) on (or below) the assembly.

[0049] Throughout this specification, unless otherwise stated, when “A and / or B” is used, it means A, B, or A and B. That is, “and / or” includes any or all of the listed items. When “from C to D” is used, it means greater than or equal to C and less than or equal to D, unless otherwise stated.

[0050] Figure 1 This is a perspective view showing the structure of a secondary battery according to an embodiment.

[0051] like Figure 1 As shown, the secondary battery 100 may include an electrode assembly 110 and a pouch 130 for housing the electrode assembly 110.

[0052] Electrode assembly 110 may include a first electrode plate 111, a second electrode plate 112, and a diaphragm 113 disposed therebetween. In some examples, electrode assembly 110 may be formed by winding a stack of the first electrode plate 111, the diaphragm 113, and the second electrode plate 112, which are formed as plates or films. In some examples, one or more electrode assemblies 110 may be stacked together such that the electrode assemblies 110 are adjacent to each other and housed in a bag 130, and in this case, the number of electrode assemblies 110 is not limited in this disclosure. The first electrode plate 111 of electrode assembly 110 may be used as a negative electrode, and the second electrode plate 112 may be used as a positive electrode, for example, or vice versa. Hereinafter, the first electrode plate 111 and the second electrode plate 112 will be referred to as negative electrode plate 111 and positive electrode plate 112, respectively.

[0053] The negative electrode plate 111 can be formed by coating a first electrode active material (e.g., graphite or carbon) onto a first electrode current collector made of a metal foil (such as copper, copper alloy, nickel, or nickel alloy). The negative electrode plate 111 may include a first electrode active material layer, which is the area to which the first electrode active material is coated. The negative electrode plate 111 may include a first uncoated portion, which is the area to which the first electrode active material is not coated.

[0054] The negative electrode plate 111 can be a negative electrode and can include negative electrode tabs 114a and 114b electrically connected to the first uncoated portion. In some examples, each of the negative electrode tabs 114a and 114b can be approximately flat and can be fixed (e.g., welded) to the first uncoated portion. For example, each of the negative electrode tabs 114a and 114b can be fixed to the first uncoated portion by ultrasonic welding, laser welding, or resistance welding. That is, one end of the negative electrode tabs 114a and 114b can be electrically connected to the first uncoated portion, and the other ends of the negative electrode tabs 114a and 114b can protrude outward and extend. In some examples, when the negative electrode plate 111 (e.g., the negative electrode plate) is manufactured, the negative electrode tabs 114a and 114b can be formed by being pre-cut to protrude to one side of the electrode assembly 110, or the negative electrode tabs 114a and 114b can protrude to one side of the electrode assembly 110 more than the separator 113 (e.g., protrude farther than the separator 113 or protrude beyond the separator 113) without separate cutting.

[0055] The negative electrode active material as the first active material can include a material capable of reversibly inserting / extracting lithium ions, lithium metal, a lithium metal alloy, a material capable of being doped and de-doped with lithium, or a transition metal oxide.

[0056] The material capable of reversibly inserting / extracting lithium ions can be a carbon negative electrode active material, which can include, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of crystalline carbon can include graphite, such as natural graphite or artificial graphite, and examples of amorphous carbon can include soft carbon, hard carbon, carbon pitch, mesophase carbon pitch, sintered coke, etc.

[0057] A silicon negative electrode active material or a tin negative electrode active material can be used as the material capable of being doped and de-doped with lithium. The silicon negative electrode active material can be silicon, a silicon-carbon composite, SiO x (0 < x ≤ 2), a silicon alloy, or a combination thereof.

[0058] 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.

[0059] The silicon-carbon composite can also include crystalline carbon. For example, the silicon-carbon composite can include a core containing crystalline carbon and silicon particles, and an amorphous carbon coating layer on the surface of the core.

[0060] The negative electrode for a lithium secondary battery can include a current collector and a negative electrode active material layer provided on the current collector. The negative electrode active material layer can include a negative electrode active material and can also include a binder and / or a conductive material.

[0061] For example, the negative electrode active material layer may include about 90 wt% to about 99.5 wt% of negative electrode active material, about 0.5 wt% to about 5 wt% of binder, and about 0 wt% to about 5 wt% of conductive material.

[0062] Non-aqueous adhesives, aqueous adhesives, dry adhesives, or combinations thereof can be used as adhesives. When aqueous adhesives are used as negative electrode adhesives, they may further include cellulose compounds capable of imparting viscosity.

[0063] A material selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, polymer substrate coated with conductive metal, and combinations thereof can be used as a negative electrode current collector.

[0064] Electrolytes used in lithium secondary batteries may include non-aqueous organic solvents and lithium salts.

[0065] Non-aqueous organic solvents serve as the medium through which ions can move in the electrochemical reactions involved in the battery. These non-aqueous organic solvents can be carbonates, esters, ethers, ketones, alcohols, or aprotic solvents, and can be used alone or in combination of two or more. Furthermore, when using carbonate solvents, mixtures of cyclic and chain carbonates can be used.

[0066] The positive electrode plate 112 (e.g., a positive electrode) can be formed by coating a second electrode active material, such as a transition metal oxide, onto a second electrode current collector formed of a metal foil such as aluminum or an aluminum alloy. The positive electrode plate 112 may include a second electrode active material layer, which is the area to which the second electrode active material is coated. The positive electrode plate 112 may include a second uncoated portion, which is the area to which the second electrode active material is not coated.

[0067] The positive electrode plate 112 may include positive electrode tabs 115a and 115b electrically connected to the second uncoated portion. In some examples, each of the positive electrode tabs 115a and 115b may be approximately flat and may be fixed (e.g., welded) to the second uncoated portion. For example, each of the positive electrode tabs 115a and 115b may be fixed to the second uncoated portion by ultrasonic welding, laser welding, or resistance welding. That is, one end of the positive electrode tabs 115a and 115b may be electrically connected to the second uncoated portion, and the other end of the positive electrode tabs 115a and 115b may protrude outward and extend. In some examples, when the positive electrode plate 112 is manufactured, the positive electrode tabs 115a and 115b can be formed by being pre-cut to protrude to one side of the electrode assembly 110, or the positive electrode tabs 115a and 115b can protrude to one side of the electrode assembly 110 beyond the diaphragm 113 (e.g., protruding further than or beyond the diaphragm 113) without separate cutting.

[0068] Compounds capable of reversibly inserting / deintercalating lithium (e.g., lithiation intercalation compounds) can be used as positive electrode active materials, which are secondary active materials. For example, at least one of lithium and a composite oxide of a metal selected from cobalt, manganese, nickel, and combinations thereof can be used.

[0069] The composite oxide can be a lithium transition metal composite oxide, and examples of it can include lithium nickel oxide, lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate compound, cobalt-free nickel manganese oxide, or combinations thereof.

[0070] For example, compounds represented by any of the following chemical 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 cO 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 L 1 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 G g 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).

[0071] In the above chemical formulas: A can be Ni, Co, Mn, or a combination thereof; X can be Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, or a combination thereof; D can be O, F, S, P, or a combination thereof; G can be Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; L 1 It can be Mn, Al, or a combination thereof.

[0072] The positive electrode for a lithium secondary battery may include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer may include a positive electrode active material, and may also include a binder and / or a conductive material.

[0073] The content of the positive electrode active material can range from 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 conductive material can range from about 0.5 wt% to about 5 wt% based on 100 wt% of the positive electrode active material layer, respectively.

[0074] The current collector can be aluminum (Al).

[0075] In some examples, electrode leads 150 may be included, such that negative electrode tabs 114a and 114b and positive electrode tabs 115a and 115b can be electrically connected to the outside. Negative electrode tabs 114a and 114b and positive electrode tabs 115a and 115b can be soldered to negative electrode leads 152 and positive electrode leads 154 of external terminals for electrical connection to the outside. A tab film 156 for insulation from the bag 130 can be attached to negative electrode leads 152 and positive electrode leads 154. The bag 130 may also be referred to as a housing.

[0076] A diaphragm 113 may be placed between the negative electrode plate 111 and the positive electrode plate 112 to prevent an electrical short circuit between the negative electrode plate 111 and the positive electrode plate 112. In practice, the diaphragms 113 may be provided as a pair, and the negative electrode plate 111 may be placed between a pair of diaphragms 113.

[0077] Depending on the type of lithium secondary battery, the separator 113 may be present between the negative electrode plate 111 (e.g., the negative electrode) and the positive electrode plate 112 (e.g., the positive electrode). Polyethylene, polypropylene, polyvinylidene fluoride, or multilayer films of two or more layers thereof may be used as the separator 113.

[0078] The diaphragm 113 may include a porous substrate and a coating layer on one or both surfaces of the porous substrate, the coating layer comprising an organic substance, an inorganic substance, or a combination thereof. The organic substance may include a polyvinylidene fluoride polymer or a (meth)acrylic acid polymer. The inorganic substance 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. The organic and inorganic substances may be mixed in a single coating layer, or may be in the form of a coating layer containing organic substances and a coating layer containing inorganic substances, layered on top of each other.

[0079] With the electrode assembly 110 housed in the bag 130, the sealing portions 132 at the edges of the bag 130 can contact each other (e.g., the sealing portions 132 around the periphery of the bottom portion of the bag 130 can contact the corresponding peripheral area of ​​the top portion (e.g., the cap) of the bag 130) to achieve a seal. Sealing can be performed with the connecting piece diaphragm 156 positioned between the sealing portions 132. Figure 1 As shown, the form in which the terminal block 156 is attached to each of the negative electrode terminals 114a and 114b and the positive electrode terminals 115a and 115b is referred to as a "separable terminal block 156" (e.g., such a sealing structure is referred to as a separable sealing structure).

[0080] The sealing portions 132 at the bottom and top portions of the bag 130 (e.g., the entire cap or at least the peripheral area of ​​the cap) can be made of a heat-fusible material and can have a structure that achieves a seal by bonding the heat-fusible layers together. Since heat-fusible materials generally have weak adhesion to metals, a thin-film connecting strip 156 can be attached to the connecting strip to fuse it to the bag 130. However, in a separable sealing structure, the connecting strip 156 is attached to the negative electrode lead 152 and the positive electrode lead 154, then welded to the negative electrode lead 152 and the positive electrode lead 154, and then heat-fused to the bag 130, thereby improving processability and productivity. The bag 130 can have an internal space, and the electrode assembly 110 can be housed within the internal space.

[0081] The thickness of the electrode plates may increase during charging of the secondary battery and may decrease during discharging. Repeated contraction / expansion of the electrode plates during cycling can cause stress concentration in the structurally vulnerable core of the electrode assembly, leading to deformation. The core of the electrode assembly can refer to the innermost part of the electrode assembly; for example, the core of the electrode assembly can be the portion that bends first from the leading edge of the winding, i.e., the leading edge bending region. For example, a wound electrode assembly may have pores in the structurally bent portion. If the negative electrode active material layer and the positive electrode active material layer are provided in a region offset from the leading edge bending region (e.g., if the active material layer is not provided on the structurally bent leading edge bending region), deformation may occur in the voids in the leading edge bending region during cycling. In contrast, according to this disclosure, the negative electrode plate active material layer and the positive electrode plate active material layer can be provided to fill the pores in the core of the electrode assembly, thereby preventing deformation of the electrode assembly.

[0082] Figure 2 This is a view showing the electrode assembly 110 of the secondary battery 100 in its state before winding, and Figure 3 It is shown Figure 2 A view of the electrode assembly 110 after winding. (Refer to...) Figure 2 The multiple dashed lines shown in the vertical direction indicate the area of ​​the fold of the electrode assembly 110, the winding area, or the number of turns during the winding process of the electrode assembly 110.

[0083] like Figure 2 As shown, in some examples, the first negative electrode tab 114a can be provided at the leading edge of the winding of the electrode assembly 110. Figure 2 (on the right side) and the second negative electrode terminal piece 114b can be provided at the winding tail edge of the electrode assembly 110 ( Figure 2(on the left side of the figure). In some examples, electrode assembly 110 may include a negative electrode plate 111, a pair of diaphragms 113a and 113b configured to cover the negative electrode plate 111, and a positive electrode plate 112. The negative electrode plate 111 includes a first negative electrode tab 114a and a second negative electrode tab 114b. In some examples, a first positive electrode tab 115a may be provided at the leading edge of the winding of the positive electrode plate 112, and a second positive electrode tab 115b may be provided at the trailing edge of the winding of the positive electrode plate 112. In some examples, the number of first electrode tabs 114a and second negative electrode tabs 114b, and the number of first positive electrode tabs 115a and second positive electrode tabs 115b may be greater than the number shown in the figure.

[0084] In some examples, the leading edge of the winding refers to the region where winding begins during the winding process of the electrode assembly 110, and the trailing edge of the winding refers to the region where winding ends during the winding process of the electrode assembly 110. Accordingly, the first negative electrode tab 114a and the first positive electrode tab 115a provided at the leading edge of the winding can typically be located at the inner periphery (or inner center) of the wound electrode assembly 110 (e.g., see...). Figure 3 The second negative electrode terminal 114b and the second positive electrode terminal 115b at the winding tail edge are typically located on the outer periphery (or outer surface) of the wound electrode assembly 110.

[0085] In some examples, each of the first negative electrode terminal 114a and the second negative electrode terminal 114b may be made of copper, copper alloy, nickel, nickel alloy, nickel / copper / nickel composite metal, nickel-plated copper, etc. In some examples, the first positive electrode terminal 115a and the second positive electrode terminal 115b may be made of aluminum, aluminum alloy, etc.

[0086] Next, the negative electrode plate 111 and the positive electrode plate 112 of the electrode assembly 110, and the organic connection between them, will be described in more detail.

[0087] In some examples, the negative electrode plate 111 may include a negative electrode current collector 111a, a first negative electrode active material layer 111h, a second negative electrode active material layer 111i, a first negative electrode terminal block 114a, and a second negative electrode terminal block 114b. The negative electrode current collector 111a may include a first negative electrode surface 111b and a second negative electrode surface 111c opposite to the first negative electrode surface 111b. Furthermore, the first negative electrode active material layer 111h may be provided on the first negative electrode surface 111b of the negative electrode current collector 111a by coating, and the second negative electrode active material layer 111i may be provided on the second negative electrode surface 111c of the negative electrode current collector 111a by coating.

[0088] In some examples, the uncoated portion 111d of the first negative electrode (corresponding to approximately 1.5 turns from one end) without the first negative electrode active material layer 111h can be provided at the leading edge of the winding on the first negative electrode surface 111b, and the uncoated portion 111e of the second negative electrode (corresponding to approximately 1.5 turns from the other end) without the first negative electrode active material layer 111h can be provided at the trailing edge of the winding on the first negative electrode surface 111b. In some examples, the uncoated portion 111f of the third negative electrode (corresponding to approximately 5 turns from one end) without the second negative electrode active material layer 111i can be provided at the leading edge of the winding on the second negative electrode surface 111c, and the uncoated portion 111g of the fourth negative electrode (corresponding to approximately 1.5 turns from the other end) without the second negative electrode active material layer 111i can be provided at the trailing edge of the winding on the second negative electrode surface 111c. In some examples, the first negative electrode tab 114a may be provided at the third uncoated portion 111f of the leading edge of the second negative electrode surface 111c, and the second negative electrode tab 114b may be provided at the fourth uncoated portion 111g of the trailing edge of the second negative electrode surface 111c.

[0089] In some examples, a pair of diaphragms 113a and 113b may cover the first uncoated negative electrode portion 111d, the second uncoated negative electrode portion 111e, the third uncoated negative electrode portion 111f, the fourth uncoated negative electrode portion 111g, the first negative electrode active material layer 111h, and the second negative electrode active material layer 111i of the negative electrode plate 111. The length of each of the pair of diaphragms 113a and 113b may be greater than the length of the negative electrode plate 111 (e.g., in each of the pair of diaphragms 113a and 113b and in the longitudinal direction of the negative electrode plate 111 in its unwound state).

[0090] In some examples, the positive electrode plate 112 may include a positive electrode current collector 112a, a first positive electrode active material layer 112h, a second positive electrode active material layer 112i, a first positive electrode terminal block 115a, and a second positive electrode terminal block 115b. The positive electrode current collector 112a may include a first positive electrode surface 112b and a second positive electrode surface 112c opposite to the first positive electrode surface 112b. Furthermore, the first positive electrode active material layer 112h may be provided on the first positive electrode surface 112b of the positive electrode current collector 112a by coating, and the second positive electrode active material layer 112i may be provided on the second positive electrode surface 112c of the positive electrode current collector 112a by coating.

[0091] In some examples, a first positive electrode uncoated portion 112d (corresponding to approximately 1.5 turns from one end) without the first positive electrode active material layer 112h can be provided at the leading edge of the winding on the first positive electrode surface 112b, and a second positive electrode uncoated portion 112e (corresponding to approximately 6.5 turns from the other end) without the first positive electrode active material layer 112h can be provided at the trailing edge of the winding on the first positive electrode surface 112b. Furthermore, a third positive electrode uncoated portion 112f (corresponding to approximately 1.5 turns from one end) without the second positive electrode active material layer 112i can be provided at the leading edge of the winding on the second positive electrode surface 112c, and a fourth positive electrode uncoated portion 112g (corresponding to approximately 3 turns from the other end) without the second positive electrode active material layer 112i can be provided at the trailing edge of the winding on the second positive electrode surface 112c. In some examples, the first positive electrode tab 115a may be provided at the first positive electrode uncoated portion 112d at the leading edge of the first positive electrode surface 112b, and the second positive electrode tab 115b may be provided at the second positive electrode uncoated portion 112e at the trailing edge of the first positive electrode surface 112b.

[0092] See Figure 3 This illustration shows the state of the electrode assembly 110 of a secondary battery 100 according to an embodiment of the present disclosure after winding. In some examples, the electrode assembly 110 may have multiple bending regions and may be wound from the leading edge to the trailing edge. For example, the leading edge bending region R1 is the portion that is first bent from the leading edge and may be referred to as the core of the electrode assembly 110. In some examples, the leading edge bending region R1 may correspond to... Figure 2 The second circle (column) starting from one end (for example, from...) Figure 2 (The second dashed line column from the right).

[0093] See Figure 2 and Figure 3 The negative electrode plate 111, positive electrode plate 112, and diaphragm 113 can be wound together to form multiple curved regions. In some examples, the negative electrode active material layers (e.g., the first negative electrode active material layer 111h and the second negative electrode active material layer 111i) and the positive electrode active material layers (e.g., the first positive electrode active material layer 112h and the second positive electrode active material layer 112i) can be aligned based on the position of the trailing edge of the leading edge curved region among the multiple curved regions of the negative electrode plate 111 and the positive electrode plate 112. For example, the coating start position of the negative electrode active material layers (e.g., the first negative electrode active material layer 111h and the second negative electrode active material layer 111i) and the positive electrode active material layers (e.g., the first positive electrode active material layer 112h and the second positive electrode active material layer 112i) can be set based on the position of the trailing edge of the leading edge curved region.

[0094] In some examples, the first negative electrode active material layer 111h of the negative electrode plate 111 can be provided from within the leading edge bending region R1 by coating. For example, see Figure 2 The edge of the first negative electrode active material layer 111h of the negative electrode plate 111 may be within the leading edge bending region R1 (e.g., extending into the leading edge bending region R1). For example, the first negative electrode active material layer 111h may be provided by coating between the leading edge and trailing edge of the leading edge bending region R1. In some examples, the first negative electrode active material layer 111h may be provided by coating approximately 1 mm to 2 mm before the trailing edge (e.g., end) of the bending region R1 (in the leading edge direction). In some examples, the electrode assembly 110 may be aligned such that the starting position of the first negative electrode active material layer 111h is approximately 1 mm to 2 mm before the trailing edge of the bending region R1 (in the leading edge direction), for example, thus the first negative electrode active material layer 111h may overlap with approximately 1 mm to 2 mm of the trailing edge of the bending region R1.

[0095] In some examples, the first positive electrode active material layer 112h of the positive electrode plate 112 can be provided by coating from a position substantially the same as the trailing edge of the leading edge bending region R1. For example, see Figure 2 The edge of the first positive electrode active material layer 112h of the positive electrode plate 112 can be aligned with the trailing edge (e.g., end) of the leading edge bending region R1 (e.g., the edge of the first positive electrode active material layer 112h can be aligned with the trailing edge (e.g., end) of the leading edge bending region R1). Figure 2 (Aligned with the third vertical dashed line from the right in the diagram). In some examples, the second positive electrode active material layer 112i of the positive electrode plate 112 can be provided from approximately the same position as the trailing edge of the leading edge bending region R1 by coating (e.g., the edges of the first positive electrode active material layer 112h and the second positive electrode active material layer 112i can be aligned). For example, the electrode assembly 110 can be aligned such that the starting positions of the first positive electrode active material layer 112h and the second positive electrode active material layer 112i are approximately equal to the trailing edge of the leading edge bending region R1. In some examples, the electrode assembly 110 can be aligned such that the first negative electrode active material layer 111h protrudes further than the second positive electrode active material layer 112i in the direction toward the winding leading edge, for example, it can protrude into the leading edge bending region R1. Accordingly, this disclosure can limit (e.g., adjust) the alignment position of the negative electrode active material layer to fill the pores in the core (e.g., in the leading edge bending region R1) that are structurally generated during the winding process, thereby preventing or substantially minimizing deformation of the core such as pits.

[0096] In some examples, the electrode assembly 110 may be arranged such that the first negative electrode surface 111b and the second positive electrode surface 112c face each other. For example, a pair of diaphragms 113a and 113b may be wound around the negative electrode plate 111, and the first negative electrode surface 111b and the second positive electrode surface 112c may be positioned facing each other such that the first positive electrode surface 112b is located at the outermost edge of the electrode assembly 110. In some examples, the uncoated portion 112e of the second positive electrode may be located at the outermost edge of the electrode assembly 110 and may be exposed to the outside while surrounding the outermost edge of the electrode assembly 110.

[0097] In some examples, the area of ​​the first negative electrode active material layer 111h may be larger than the area of ​​the second negative electrode active material layer 111i. In some examples, the area of ​​the second positive electrode active material layer 112i may be larger than the area of ​​the first positive electrode active material layer 112h. In some examples, the area of ​​each of the separators 113a and 113b may be larger than the area of ​​each of the negative electrode plate 111 and the positive electrode plate 112. In some examples, the area of ​​the positive electrode active material layer may be smaller than the area of ​​the negative electrode active material layer; for example, the sum of the areas of the first positive electrode active material layer 112h and the second positive electrode active material layer 112i may be smaller than the sum of the areas of the first negative electrode active material layer 111h and the second negative electrode active material layer 111i.

[0098] Figure 4 This is a view showing the state of the electrode assembly of a secondary battery according to another embodiment of the present disclosure before winding. Figure 5 This is a view showing the state of the electrode assembly of a secondary battery according to another embodiment of the present disclosure after winding.

[0099] Figure 4 and Figure 5 Electrode assembly 210 is shown, which is different from the electrode assembly 210. Figure 2 and Figure 3 The number of turns of the electrode assembly 110 shown is the number of turns of the winding. In some examples, the secondary battery 200 may be similar in configuration to the secondary battery 100 except for the number of turns of the electrode assembly 210 (e.g., such that the winding and trailing edges of each of the electrode plates are arranged differently relative to the center of the winding structure), and descriptions of the same configuration will be omitted.

[0100] like Figure 4 As shown, in some examples, the first negative electrode tab 214a can be provided at the leading edge of the winding of the electrode assembly 210. Figure 4 (on the right side of the middle), and the second negative electrode terminal piece 214b can be disposed at the winding tail edge of the electrode assembly 210 ...). Figure 4(on the left side of the figure). In some examples, electrode assembly 210 may include a negative electrode plate 211, a pair of diaphragms 213a and 213b configured to cover the negative electrode plate 211, and a positive electrode plate 212, the negative electrode plate 211 including a first negative electrode tab 214a and a second negative electrode tab 214b. In some examples, a first positive electrode tab 215a may be provided at the leading edge of the winding of the positive electrode plate 212, and a second positive electrode tab 215b may be provided at the trailing edge of the winding of the positive electrode plate 212. In some examples, the number of first negative electrode tabs 214a and 214b, as well as the number of first positive electrode tabs 215a and 215b, may be greater than the number shown in the figure.

[0101] In some examples, the first negative electrode tab 214a and the first positive electrode tab 215a provided at the leading edge of the winding are generally located at the inner periphery (or inner center) of the wound electrode assembly 210, and the second negative electrode tab 214b and the second positive electrode tab 215b provided at the trailing edge of the winding are generally located at the outer periphery (or outer surface) of the wound electrode assembly 210.

[0102] In some examples, the negative electrode plate 211 may include a negative electrode current collector 211a, a first negative electrode active material layer 211h, a second negative electrode active material layer 211i, a first negative electrode terminal block 214a, and a second negative electrode terminal block 214b. The negative electrode current collector 211a may include a first negative electrode surface 211b and a second negative electrode surface 211c opposite to the first negative electrode surface 211b. Furthermore, the first negative electrode active material layer 211h may be provided on the first negative electrode surface 211b of the negative electrode current collector 211a by coating, and the second negative electrode active material layer 211i may be provided on the second negative electrode surface 211c of the negative electrode current collector 211a by coating.

[0103] In some examples, the uncoated portion 211d of the first negative electrode (corresponding to approximately 1.5 turns from one end) without the first negative electrode active material layer 211h can be provided at the leading edge of the winding on the first negative electrode surface 211b, and the uncoated portion 211e of the second negative electrode (corresponding to approximately 1.5 turns from the other end) without the first negative electrode active material layer 211h can be provided at the trailing edge of the winding on the first negative electrode surface 211b. In some examples, the uncoated portion 211f of the third negative electrode (corresponding to approximately 5 turns from one end) without the second negative electrode active material layer 211i can be provided at the leading edge of the winding on the second negative electrode surface 211c, and the uncoated portion 211g of the fourth negative electrode (corresponding to approximately 1.5 turns from the other end) without the second negative electrode active material layer 211i can be provided at the trailing edge of the winding on the second negative electrode surface 211c. In some examples, the first negative electrode tab 214a may be provided at the third uncoated portion 211f of the winding leading edge of the second negative electrode surface 211c, and the second negative electrode tab 214b may be provided at the fourth uncoated portion 211g of the winding trailing edge of the second negative electrode surface 211c.

[0104] In some examples, a pair of membranes 213a and 213b may cover the first uncoated negative electrode portion 211d, the second uncoated negative electrode portion 211e, the third uncoated negative electrode portion 211f, the fourth uncoated negative electrode portion 211g, the first negative electrode active material layer 211h, and the second negative electrode active material layer 211i of the negative electrode plate 211. The length of each of the pair of membranes 213a and 213b may be greater than the length of the negative electrode plate 211.

[0105] In some examples, the positive electrode plate 212 may include a positive electrode current collector 212a, a first positive electrode active material layer 212h, a second positive electrode active material layer 212i, a first positive electrode terminal block 215a, and a second positive electrode terminal block 215b. The positive electrode current collector 212a may include a generally flat first positive electrode surface 212b and a generally flat second positive electrode surface 212c opposite to the first positive electrode surface 212b. Furthermore, the first positive electrode active material layer 212h may be provided on the first positive electrode surface 212b of the positive electrode current collector 212a by coating, and the second positive electrode active material layer 212i may be provided on the second positive electrode surface 212c of the positive electrode current collector 212a by coating.

[0106] In some examples, a first positive electrode uncoated portion 212d (corresponding to approximately 1.5 turns from one end) without the first positive electrode active material layer 212h can be provided at the leading edge of the winding on the first positive electrode surface 212b, and a second positive electrode uncoated portion 212e (corresponding to approximately 7.5 turns from the other end) without the first positive electrode active material layer 212h can be provided at the trailing edge of the winding on the first positive electrode surface 212b. Furthermore, a third positive electrode uncoated portion 212f (corresponding to approximately 1.5 turns from one end) without the second positive electrode active material layer 212i can be provided at the leading edge of the winding on the second positive electrode surface 212c, and a fourth positive electrode uncoated portion 212g (corresponding to approximately 3.5 turns from the other end) without the second positive electrode active material layer 212i can be provided at the trailing edge of the winding on the second positive electrode surface 212c. In some examples, the first positive electrode tab 215a may be provided at the first positive electrode uncoated portion 212d at the leading edge of the first positive electrode surface 212b, and the second positive electrode tab 215b may be provided at the second positive electrode uncoated portion 212e at the trailing edge of the first positive electrode surface 212b.

[0107] See Figure 5 This illustration shows the state of the electrode assembly 210 of a secondary battery 200 according to an embodiment of the present disclosure after winding. In some examples, the electrode assembly 210 may have multiple bending regions and may be wound from the leading edge to the trailing edge. For example, the leading edge bending region R2 is the portion that first bends from the leading edge and may be referred to as the core of the electrode assembly 210. In some examples, the leading edge bending region R2 may correspond to approximately from... Figure 4 The second circle (column) starting from one end.

[0108] See Figure 4 and Figure 5 The first negative electrode active material layer 211h of the negative electrode plate 211 can be provided by coating from within the leading edge bending region R2. For example, the first negative electrode active material layer 211h can be provided by coating between the leading edge and the trailing edge of the leading edge bending region R2. In some examples, the first negative electrode active material layer 211h can be provided by coating at approximately 1 mm to 2 mm before the trailing edge of the bending region R2, for example, extending 1 mm to 2 mm into the bending region R2. In some examples, the first positive electrode active material layer 212h of the positive electrode plate 212 can be provided by coating from approximately the same position as the trailing edge of the leading edge bending region R2. Accordingly, this disclosure can limit the alignment position of the negative electrode active material layers, regardless of the number of turns of the electrode assembly, to fill the voids in the core that structurally occur during winding, thereby minimizing deformation of the core such as pits.

[0109] Figure 6 This is a schematic view illustrating a smartphone equipped with a secondary battery according to an embodiment of the present disclosure. Figure 6 As shown, the secondary battery 10 according to the above embodiments of the present disclosure can be a small battery installed in a small portable device such as a smartphone 1000. In this case, since the exemplary secondary battery 10 is configured to increase its capacity while having a slim internal structure, the above-described secondary battery 10 can be a battery suitable for application in small portable devices. As used herein, the terms "secondary battery" and "battery" have the same meaning, differing only for the sake of descriptive convenience. Figure 6 The secondary battery 10 can have the structure of either the aforementioned secondary battery 100 or secondary battery 200.

[0110] The secondary battery according to the above embodiment can be enlarged in size for use in manufacturing battery packs.

[0111] Figure 7A and Figure 7B Perspective views of the battery pack 30 with and without the second housing are shown respectively. See also Figure 7A and Figure 7B The battery pack 30 may include a plurality of battery modules 20 and a housing 31 for accommodating the plurality of battery modules 20. For example, the housing 31 may include a first housing 31-1 and a second housing 31-2, which are connected in opposite directions via the plurality of battery modules 20. The plurality of battery modules 20 may be electrically connected to each other using a busbar 25-1, and the plurality of battery modules 20 may be electrically connected to each other in series / parallel or a series-parallel hybrid manner to obtain the desired (e.g., required) power output.

[0112] Figure 8A and Figure 8B Examples include perspective and side views of the vehicle body 40 and vehicle components.

[0113] exist Figure 8A In this vehicle, the battery pack 30 may include a first housing 30-1 (e.g., a battery pack cover) and a second housing 30-2 (e.g., a battery pack frame). The first housing 30-1 is part of the vehicle floor 41, and the second housing 30-2 is located below the vehicle floor 41. The second housing 30-2 and the first housing 30-1 may be integrally formed with the vehicle floor 42. The vehicle floor 41 separates the interior and exterior of the vehicle, and the second housing 30-2 may be located on the exterior of the vehicle.

[0114] See Figure 8BThe vehicle 50 can be formed by attaching additional components such as a front hood 51 at the front of the vehicle and fenders 52 located at the front and rear of the vehicle to the body 40. The vehicle 50 may include a battery pack 30, which includes a first housing 30-1 and a second housing 30-2, and the battery pack 30 can be connected to the body 40.

[0115] According to this disclosure, the alignment position of the active material layer of the electrode plate can be set based on the bending region of the leading edge of the electrode assembly, and the pores of the core of the electrode assembly, which is a stress concentration point during cycling, can be filled to prevent deformation of the electrode assembly.

[0116] Exemplary embodiments are disclosed herein. Although specific terminology is used, it is used and interpreted in a general and descriptive sense only and not for limiting purposes. In some cases, as will be apparent to those skilled in the art at the time of filing of this application, features, characteristics, and / or elements described in connection with particular embodiments may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments, unless expressly stated otherwise. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

Claims

1. An electrode assembly, comprising: A negative electrode plate includes a negative electrode current collector and a layer of negative electrode active material on a portion of each of the opposite surfaces of the negative electrode current collector; A positive electrode plate includes a positive electrode current collector and a layer of positive electrode active material on a portion of each of the opposite surfaces of the positive electrode current collector; as well as A diaphragm is located between the negative electrode plate and the positive electrode plate. in: The negative electrode plate, the positive electrode plate, and the diaphragm are wound together to form multiple curved regions, and The negative electrode active material layer and the positive electrode active material layer are aligned based on the position of the trailing edge of the leading edge bending region in the plurality of bending regions of the negative electrode plate and the positive electrode plate.

2. The electrode assembly of claim 1, wherein the negative electrode active material layer extends into the region between one of the trailing edges of the leading edge bending region and the leading edge of one of the leading edge bending regions.

3. The electrode assembly of claim 2, wherein the negative electrode active material layer extends within a distance of 1 mm to 2 mm from one of the trailing edges.

4. The electrode assembly of claim 1, wherein the positive electrode active material layer is aligned with one of the trailing edges of the leading edge bending region.

5. The electrode assembly according to claim 1, wherein: The negative electrode current collector of the negative electrode plate has a first negative electrode surface and a second negative electrode surface opposite to the first negative electrode surface. The negative electrode active material layer includes a first negative electrode active material layer on the first negative electrode surface and a second negative electrode active material layer on the second negative electrode surface. The positive electrode current collector of the positive electrode plate has a first positive electrode surface and a second positive electrode surface opposite to the first positive electrode surface, and the positive electrode active material layer includes a first positive electrode active material layer on the first positive electrode surface and a second positive electrode active material layer on the second positive electrode surface.

6. The electrode assembly of claim 5, wherein the negative electrode plate and the positive electrode plate are arranged such that the first negative electrode surface and the second positive electrode surface face each other.

7. The electrode assembly according to claim 5, wherein: The uncoated portions of the first and second negative electrodes, which are not coated with the first negative electrode active material layer, are located at the leading and trailing edges of the first negative electrode surface, respectively. The uncoated portions of the third and fourth negative electrodes, which are not coated with the second negative electrode active material layer, are located at the leading edge and trailing edge of the second negative electrode surface, respectively.

8. The electrode assembly according to claim 7, wherein the first negative electrode terminal and the second negative electrode terminal are located at the uncoated portion of the third negative electrode and the uncoated portion of the fourth negative electrode, respectively.

9. The electrode assembly of claim 7, wherein the first negative electrode active material layer begins between one of the trailing edges of the leading edge bending region and the leading edge of one of the leading edge bending regions.

10. The electrode assembly of claim 7, wherein the first negative electrode active material layer is within 1 mm to 2 mm of one of the trailing edges in the leading edge bending region.

11. The electrode assembly according to claim 7, wherein the area of ​​the first negative electrode active material layer is greater than the area of ​​the second negative electrode active material layer.

12. The electrode assembly according to claim 5, wherein: The uncoated portions of the first and second positive electrodes, neither of which are coated with the first positive electrode active material layer, are located at the leading and trailing edges of the winding on the surface of the first positive electrode, respectively. The uncoated portions of the third and fourth positive electrodes, which are not coated with the second positive electrode active material layer, are located at the leading edge and trailing edge of the second positive electrode surface, respectively.

13. The electrode assembly of claim 12, wherein the first positive electrode terminal and the second positive electrode terminal are located at the uncoated portion of the first positive electrode and the uncoated portion of the second positive electrode, respectively.

14. The electrode assembly of claim 12, wherein the second positive electrode active material layer begins from one of the trailing edges of the leading edge bending region.

15. The electrode assembly of claim 12, wherein the uncoated portion of the second positive electrode is on the outermost side of the electrode assembly and is exposed to the outside while surrounding the outermost side of the electrode assembly.

16. The electrode assembly of claim 12, wherein the area of ​​the second positive electrode active material layer is greater than the area of ​​the first positive electrode active material layer.

17. The electrode assembly of claim 5, wherein the first negative electrode active material layer is aligned to protrude further than the second positive electrode active material layer in the direction toward the leading edge of the winding.

18. The electrode assembly of claim 1, wherein the area of ​​the diaphragm is greater than the area of ​​each of the positive electrode plate and the negative electrode plate.

19. The electrode assembly of claim 1, wherein the area of ​​the positive electrode active material layer is smaller than the area of ​​the negative electrode active material layer.

20. A secondary battery, comprising: Electrode assembly according to any one of claims 1 to 19; as well as A housing having an internal space, the housing housing the electrode assembly within the internal space.

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