Electrode assembly and secondary battery including the same

Abstract

Disclosed are an electrode assembly and a secondary battery including the same. An electrode assembly includes: a first electrode plate including a first electrode substrate having a first electrode active material layer thereon; a first diaphragm; the second electrode plate comprises a second electrode substrate, and a second electrode active material layer is arranged on the second electrode substrate; and a second diaphragm. The first electrode plate, the first diaphragm, the second electrode plate, and the second diaphragm are sequentially stacked and wound about a winding axis, and the first electrode substrate, the first diaphragm, and the second diaphragm extend at least one turn beyond a distal end of the second electrode plate in the wound electrode assembly.

Description

Technical Field

[0001] Aspects of embodiments of the present disclosure relate to an electrode assembly and a secondary battery including the electrode assembly. Background Art

[0002] Lithium ion secondary batteries are widely used as power sources for hybrid and electric vehicles, and portable electronic devices due to their relatively high operating voltage and relatively high energy density per unit weight.

[0003] Secondary batteries can be classified into cylindrical, prismatic, and pouch-type secondary batteries. For example, a cylindrical secondary battery generally includes a can having a cylindrical shape, an electrode assembly wound in a cylindrical shape and inserted into the can, an electrolyte injected into the can, and a cap assembly coupled to the can.

[0004] During charge / discharge, the electrode assembly may be undesirably deformed due to expansion of the electrode plates, which may cause cracking.

[0005] The information disclosed in this section is provided for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not constitute related (or prior) art. Summary of the Invention

[0006] Embodiments of the present disclosure provide an electrode assembly exhibiting improved safety and a secondary battery including the same.

[0007] An electrode assembly according to one embodiment of the present disclosure includes: a first electrode plate, including a first electrode substrate, the first electrode substrate having a first electrode active material layer thereon; a first separator; a second electrode plate, including a second electrode substrate, the second electrode substrate having a second electrode active material layer thereon; and a second separator. The first electrode plate, the first separator, the second electrode plate, and the second separator are stacked sequentially and wound around a winding axis, and the first electrode substrate, the first separator, and the second separator extend beyond a distal end of the second electrode plate by at least one turn (or 360°).

[0008] The first electrode substrate, the first diaphragm, and the second diaphragm may extend beyond the distal end of the second electrode plate by about 1 to about 1.5 turns.

[0009] The first electrode substrate, the first diaphragm, and the second diaphragm may extend beyond the distal end of the second electrode plate by approximately 360° to approximately 540°.

[0010] The first electrode substrate may extend beyond distal ends of both the first diaphragm and the second diaphragm.

[0011] The first electrode substrate may extend beyond distal ends of both the first diaphragm and the second diaphragm by less than about 0.5 turns.

[0012] The first electrode substrate may extend beyond distal ends of both the first diaphragm and the second diaphragm by less than approximately 180°.

[0013] A distal end of the second electrode active material layer may overlap with a distal end of the second electrode substrate.

[0014] A distal end of the first electrode active material layer may overlap with a distal end of the second electrode active material layer.

[0015] The first electrode active material layer may extend beyond the distal end of the second electrode plate by about 5 mm to about 15 mm.

[0016] The second electrode active material layer may be on both surfaces of the second electrode substrate.

[0017] The first electrode active material layer may be on both surfaces of the first electrode substrate, and in the last circle section, the first electrode active material layer may be on only one surface of the first electrode substrate facing the interior of the electrode assembly.

[0018] The first electrode active material layer may be on both surfaces of the first electrode substrate, and in a last 360° section of the first electrode active material layer, the first electrode active material layer may be on only one surface of the first electrode substrate facing the interior of the electrode assembly.

[0019] The distal end of the first diaphragm may coincide with the distal end of the second diaphragm.

[0020] In a portion of the electrode assembly, when viewed in a longitudinal cross-section passing through the winding axis and the distal ends of both the first and second diaphragms, the first electrode substrate, the first diaphragm, the second diaphragm, and the first electrode substrate can be arranged sequentially in this order from the outside of the electrode assembly.

[0021] The second electrode plate may be surrounded by the first electrode substrate, the first diaphragm, and the second diaphragm.

[0022] An outer peripheral surface of the electrode assembly may be surrounded by the first electrode substrate.

[0023] The electrode assembly may further include a terminating tape configured to secure a distal end of the first electrode substrate.

[0024] The terminating tape may comprise polyethylene terephthalate (PET).

[0025] The termination tape may have a thickness in a range of about 15 μm to about 20 μm.

[0026] The terminating tape may be attached to at least one of an upper portion, a lower portion, and a middle portion of the electrode assembly.

[0027] A secondary battery according to an embodiment of the present disclosure includes: the electrode assembly as described above; a case accommodating the electrode assembly and electrically connected to the first electrode plate of the electrode assembly; a cover coupled to the case; and a terminal electrically connected to the second electrode plate of the electrode assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings incorporated into this specification illustrate embodiments of the present disclosure and, in conjunction with the detailed description below, further illustrate aspects and features of the present disclosure. The present disclosure should not be construed as being limited to the drawings. In the drawings:

[0029] Figure 1 is a schematic diagram of an electrode assembly according to one embodiment;

[0030] Figure 2 yes Figure 1 A schematic cross-sectional view of the electrode assembly shown in ;

[0031] Figure 3 yes Figure 2 A schematic longitudinal cross-sectional view of the electrode assembly shown in ;

[0032] Figure 4 yes Figures 1 to 3 Schematic diagram of the first electrode plate, the first separator, the second electrode plate and the second separator of the electrode assembly shown in ;

[0033] Figure 5 is a schematic diagram of a secondary battery including an electrode assembly according to an embodiment; and

[0034] Figure 6 is a schematic cross-sectional view of a secondary battery including an electrode assembly according to another embodiment. DETAILED DESCRIPTION

[0035] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0036] The embodiments are provided to more fully illustrate the aspects and features of the present disclosure to those skilled in the art, and the following embodiments may be modified in various other forms. The scope of the present disclosure is not limited to the following embodiments. These embodiments are provided to make the present disclosure more accurate and complete, and to fully convey the aspects and features of the present disclosure to those skilled in the art.

[0037] It should be understood that when an element or layer is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it can be directly on, connected to, or coupled to the other element or layer, or one or more intervening elements or layers may be present. When an element or layer is referred to as being “directly on,” “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 to” or “connected to” a second element, the first element may be directly coupled or connected to the second element, or the first element may be indirectly coupled or connected to the second element via one or more intervening elements.

[0038] In the accompanying drawings, for the clarity of illustration, the sizes of various elements, layers, etc. can be magnified. The same reference numerals indicate the same elements. As used herein, the term "and / or" includes any and all combinations of one or more related listed items. Further, the "may" used when describing the embodiments of the present disclosure relates to "one or more embodiments of the present disclosure". Expressions such as "at least one of..." and "any one of..." modify the entire list of elements when placed before / after the list of elements, rather than modifying the individual elements in the list. For example, the expression "at least one of a, b, and c" indicates only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof. As used herein, the terms "use" and "for" can be considered to be synonymous with the terms "utilize" and "utilized," respectively. As used herein, the terms "substantially," "about," and similar terms are used as approximate terms rather than terms of degree, and are intended to take into account the inherent variations of measurements or calculated values that will be recognized by those of ordinary skill in the art.

[0039] It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or sections in this article, 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, without departing from the teachings of the example embodiments, the first element, component, region, layer or section discussed below can be referred to as a second element, component, region, layer or section.

[0040] For ease of description, spatially relative terms such as "below," "beneath," "down," "above," "on," etc. may be used herein to describe the relationship of an element or feature to another element or feature as illustrated. It should be understood that the spatially relative terms are intended to encompass different orientations of the device when in use or operation in addition to the orientations described in the drawings. For example, if the device in the drawings is flipped, an element or feature described as "below" or "beneath" other elements or features may be oriented to be "above" or "above" the other elements or features. Thus, the term "below" may encompass both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used herein should be interpreted accordingly.

[0041] The terms used herein are for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form "a" and "an" are also intended to include the plural form. It will be further understood that when used in this specification, the terms "comprise" and / or "include" specify the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups thereof.

[0042] Figure 1 is a schematic diagram of an electrode assembly 100 according to one embodiment. Figure 2 yes Figure 1 A schematic cross-sectional view of an electrode assembly 100 is shown in FIG. Figure 2 The cross section shown in FIG is a cross section cut along a plane perpendicular to the winding axis of the electrode assembly 100. For convenience of description, illustration of a portion of the central portion of the electrode assembly 100 and the terminating tape 150 is omitted. Figure 3 yes Figure 2 Schematic longitudinal cross-sectional view of the electrode assembly 100 shown in FIG. Figure 3 The longitudinal cross section shown in FIG is a longitudinal cross section cut along a plane passing through the winding axis of the electrode assembly 100 and the distal ends 120a and 140a of the first and second separators 120 and 140 of the electrode assembly 100. For ease of description, only the peripheral portion of the electrode assembly 100 is illustrated, and illustration of the terminating tape 150 is omitted. Figure 4 yes Figure 2 and Figure 3 Schematic diagram of the first electrode plate 110, the first separator 120, the second electrode plate 130, and the second separator 140 of the electrode assembly 100 shown in FIG. For ease of description, only distal portions of the above components are illustrated.

[0043] It should be understood that the types, shapes, structures, etc. of the components shown in the drawings do not reflect their actual types, shapes, structures, etc., and their sizes, positions, proportions, etc. may be enlarged or distorted for the sake of convenience of description.

[0044] refer to Figures 1 to 4 The electrode assembly 100 according to an embodiment may include a first electrode plate 110 , a first separator 120 , a second electrode plate 130 , a second separator 140 , and a termination tape 150 .

[0045] The first electrode plate 110 may be any one of a negative electrode plate and a positive electrode plate. Hereinafter, as an example, the first electrode plate 110 will be described as a negative electrode plate.

[0046] The first electrode plate 110 may include a first electrode substrate 111 formed as a conductive metal thin plate, such as copper foil or nickel foil or mesh, having a first electrode active material layer 112 formed thereon by coating a first electrode active material on the first electrode substrate 111 .

[0047] The portion of the first electrode substrate 111 on which the first electrode active material layer 112 is not formed (or coated) may be referred to as a first electrode uncoated portion and may serve as a passage for current to flow from the first electrode plate 110 to the outside. In some embodiments, the first electrode uncoated portion may be located proximal to the first electrode substrate 111, may be disposed along the upper and / or lower ends of the first electrode substrate 111, or may be located in the middle of the first electrode substrate 111.

[0048] The first electrode active material may include, for example, carbon-based materials, Si, Sn, tin oxide, tin alloy composites, transition metal oxides, lithium metal nitrite, or other metal oxides.

[0049] The first separator 120 may be interposed between the first electrode plate 110 and the second electrode plate 130 to prevent an electrical short circuit between the first electrode plate 110 and the second electrode plate 130 .

[0050] The first separator 120 may be made of, for example, polyethylene, polypropylene, or a porous copolymer of polyethylene and polypropylene.

[0051] The second electrode plate 130 may be the other of a negative electrode plate and a positive electrode plate. Hereinafter, as an example, the second electrode plate 130 will be described as a positive electrode plate.

[0052] The second electrode plate 130 may include a second electrode substrate 131 formed as a conductive metal thin plate, such as aluminum foil or mesh, and a second electrode active material layer 132 formed by coating a second electrode active material on the second electrode substrate 131 .

[0053] The portion of the second electrode substrate 131 on which the second electrode active material layer 132 is not formed may be referred to as a second electrode uncoated portion and may serve as a passage for current to flow from the second electrode plate 130 to the outside. In some embodiments, the second electrode uncoated portion may be located proximal to the second electrode substrate 131, may be disposed along the lower end and / or upper end of the second electrode substrate 131, or may be located in the middle of the second electrode substrate 131.

[0054] The second electrode active material may include a chalcogenide, for example, a composite metal oxide such as LiCoO 2 , LiMn 2 O 4 , LiNiO 2 , or LiNiMnO 2 .

[0055] The second separator 140 may be interposed between the first electrode plate 110 and the second electrode plate 130 to prevent an electrical short circuit between the first electrode plate 110 and the second electrode plate 130 .

[0056] The second separator 140 may be made of, for example, polyethylene, polypropylene, or a porous copolymer of polyethylene and polypropylene.

[0057] The first electrode plate 110, the first separator 120, the second electrode plate 130, and the second separator 140 may be stacked sequentially and wound around a common axis (e.g., a winding axis). In this specification, an end portion of each of the first electrode plate 110, the first separator 120, the second electrode plate 130, and the second separator 140 that is close to the winding axis, for example, an end portion thereof located in the center portion of the electrode assembly 100, will be referred to as a proximal end, and an end portion of each of the first electrode plate 110, the first separator 120, the second electrode plate 130, and the second separator 140 that is away from the winding axis, for example, an end portion thereof located in the peripheral portion of the electrode assembly 100, will be referred to as a distal end.

[0058] like Figure 2 and Figure 4 As can be seen in FIG, the second electrode active material layer 132 may be formed up to the distal end of the second electrode substrate 131. For example, the distal end of the second electrode active material layer 132 may coincide with (or may be parallel to) the distal end of the second electrode substrate 131, and the coincidence point may be the distal end 130a of the second electrode plate 130.

[0059] The second electrode active material layer 132 may be formed on both surfaces of the second electrode substrate 131. For example, the second electrode active material layer 132 may be formed on one surface of the second electrode substrate 131 facing the interior of the electrode assembly 100 and on the other surface of the second electrode substrate 131 facing the exterior of the electrode assembly 100.

[0060] like Figure 2 and Figure 4As can be seen in the figure, the distal end 112a of the first electrode active material layer 112 can coincide with its point corresponding to the distal end 130a of the second electrode plate 130 (for example, the point at which a straight line perpendicular to the winding axis and passing through the winding axis and the distal end 130a of the second electrode plate 130 intersects with the first electrode active material layer 112 adjacent to the distal end 130a of the second electrode plate 130 in the outward direction of the electrode assembly 100), or can extend slightly longer than this point, for example, in the range of about 5 mm to about 15 mm. As used herein, the term "coincidence" is intended not only to mean exactly coinciding, but also to mean substantially coinciding, and should be interpreted as encompassing embodiments in which one element is slightly longer or shorter than the other element due to errors or deviations in the winding process or other manufacturing processes. The first electrode active material layer 112 is illustrated in the drawings as extending slightly longer than its point corresponding to the distal end 130a of the second electrode plate 130 (for example, illustrated as extending slightly beyond the distal end 130a of the second electrode plate 130).

[0061] The first electrode active material layer 112 may be formed on both surfaces of the first electrode substrate 111. Figure 2 As can be seen in the figure, in the last lap section (e.g., having an angular length of 360°) of the first electrode active material layer 112, only one surface of the first electrode substrate 111 facing the interior of the electrode assembly 100 can face the second electrode active material layer 132 and electrochemically interact therewith. Therefore, in the last lap section (360°) of the first electrode active material layer 112, the first electrode active material layer 112 can be formed only on one surface of the first electrode substrate 111 facing the interior of the electrode assembly 100, and may not be formed on the other surface of the first electrode substrate 111 facing the exterior of the electrode assembly 100.

[0062] like Figure 2 and Figure 4As can be seen in the figure, the first electrode substrate 111 can be longer than the distal end 112a of the extended first electrode active material layer 112 (for example, can extend beyond the distal end 112a of the first electrode active material layer 112 or can extend through the distal end 112a of the first electrode active material layer 112). For example, the first electrode substrate 111, the first diaphragm 120 and the second diaphragm 140 can extend at least one circle (360°) longer than the points corresponding to the distal end 130a of the second electrode plate 130 (for example, the point at which a straight line perpendicular to the winding axis and passing through the winding axis and the distal end 130a of the second electrode plate 130 intersects the first electrode substrate 111 adjacent to the distal end 130a of the second electrode plate 130 in the outward direction of the electrode assembly 100, the point at which a straight line perpendicular to the winding axis and passing through the winding axis and the distal end 130a of the second electrode plate 130 intersects the first diaphragm 120 adjacent to the distal end 130a of the second electrode plate 130 in the outward direction of the electrode assembly 100, and the point at which a straight line perpendicular to the winding axis and passing through the winding axis and the distal end 130a of the second electrode plate 130 intersects the second diaphragm 140 adjacent to the distal end 130a of the second electrode plate 130 in the inward direction of the electrode assembly 100). For example, the first electrode substrate 111, the first diaphragm 120, and the second diaphragm 140 may be further wound at least one turn (360°) from the point corresponding to the distal end 130a of the second electrode plate 130. Therefore, the second electrode plate 130 may be completely surrounded by the first electrode substrate 111, the first diaphragm 120, and the second diaphragm 140.

[0063] However, if the first electrode substrate 111, the first separator 120, and the second separator 140 are excessively extended (e.g., excessively extended beyond the distal end 130a of the second electrode plate 130), the capacity per unit volume of the secondary battery may be reduced. Therefore, the first electrode substrate 111, the first separator 120, and the second separator 140 may be extended to be less than about 1.5 turns (e.g., having an angular length of 540°) beyond the point corresponding to the distal end 130a of the second electrode plate 130.

[0064] As a result, the first electrode substrate 111 , the first diaphragm 120 , and the second diaphragm 140 may extend about 1 to about 1.5 turns (about 360° to about 540°) longer than their point corresponding to the distal end 130 a of the second electrode plate 130 .

[0065] like Figure 2 and Figure 4As can be seen in FIG, the distal end 120a of the first separator 120 may coincide with a point corresponding to the distal end 140a of the second separator 140 (e.g., a point at which a straight line perpendicular to the winding axis and passing through the winding axis and the distal end 140a of the second separator 140 intersects the first separator 120 immediately adjacent to the distal end 140a of the second separator 140 in an outward direction of the electrode assembly 100). As used herein, the term "coincide" is intended to mean not only exactly coincide but also substantially coincide, and should be interpreted to encompass embodiments in which one element is slightly longer or shorter than the other due to errors or deviations in the winding process or other manufacturing processes.

[0066] In addition, if Figure 2 and Figure 4 As can be seen in FIG, the first electrode substrate 111 can extend longer than the point corresponding to the distal end 120a of the first diaphragm 120 and the distal end 140a of the second diaphragm 140 (for example, the point at which a straight line perpendicular to the winding axis and passing through the winding axis and the distal ends 120a, 140a of the first diaphragm 120 and the distal end 140a of the second diaphragm 140 intersects the first electrode substrate 111 adjacent to the distal ends 120a, 140a of the first diaphragm 120 and the distal end 140a of the second diaphragm 140 in the outward direction of the electrode assembly 100). For example, it can extend beyond the point corresponding to the distal end 120a, 140a of the first diaphragm 120 and the distal end 140a of the second diaphragm 140). Therefore, the outer peripheral surface of the electrode assembly 100 can be completely surrounded by the first electrode substrate 111.

[0067] However, if the first electrode substrate 111 is excessively extended, the capacity per unit volume of the secondary battery may be reduced. Therefore, the first electrode substrate 111 may be extended to be less than about 0.5 turns (e.g., an angular length of about 180°) longer than the points corresponding to the distal ends 120a of the first separator 120 and 140a of the second separator 140.

[0068] like Figure 3 As can be seen, the above-mentioned electrode assembly 100 can have the following cross-section: when viewed in a longitudinal cross-section passing through the winding axis and the distal end 120a of the first diaphragm 120 and the distal end 140a of the second diaphragm 140, the first electrode substrate 111, the first diaphragm 120, the second diaphragm 140 and the first electrode substrate 111 are arranged in this order from the outside of the electrode assembly 100.

[0069] Since the electrode assembly 100 is additionally surrounded and protected from the outside by the first electrode substrate 111 and the first and second separators 120 and 140, the first and second electrode active material layers 112 and 132 located on the opposite inner sides of the electrode assembly 100 will not crack even when the electrode plates expand during charge / discharge and pressure is applied thereto from the outside.

[0070] Furthermore, since heat or shock applied from the outside is absorbed by the first electrode substrate 111 and the first and second separators 120 and 140, safety can be improved. In addition, since the first and second separators 120 and 140 can be impregnated with an electrolyte in the peripheral area, a channel for the electrolyte to move can be provided, and thus the electrolyte can be prevented from accumulating in the peripheral area.

[0071] The terminating tape 150 may fix the distal end 111 a of the first electrode substrate 111 to prevent it from being loosened.

[0072] The termination tape 150 may include, for example, polyethylene terephthalate (PET) or be made of, for example, polyethylene terephthalate (PET), and may have a thickness in the range of about 15 μm to about 20 μm. Compared to conventional examples that use a relatively thick oriented polystyrene (OPS) film having a thickness of about 30 μm to prevent or minimize cracking, embodiments of the present disclosure can avoid increases in volume and cost due to the termination tape 150.

[0073] The terminating tape 150 is illustrated in the drawings as being attached to the upper and lower portions of the electrode assembly 100. However, in some embodiments, the terminating tape 150 may be attached to the middle of the electrode assembly 100 or to a large area between the upper and lower portions of the electrode assembly 100.

[0074] Figure 5 is a schematic diagram of a secondary battery including the electrode assembly 100 as described above. However, Figure 5 The secondary battery shown in FIG. 1 is merely one example of various types of secondary batteries that may use or include the electrode assembly 100 described above.

[0075] refer to Figure 5 , a secondary battery may include an electrode assembly 100 , a case 200 , a first current collector 300 , a cap plate (or cover) 400 , a first gasket 500 , a second current collector 600 , a terminal 700 , and a second gasket 800 .

[0076] The configuration of the electrode assembly 100 is the same as described above, and thus repeated description thereof will be omitted.

[0077] The housing 200 may have a cylindrical shape. For example, the housing 200 may have an upper portion formed in the shape of a circular plate and a side portion extending downward from the edge of the upper portion. The housing 200 may have an open lower surface (or lower end). The electrode assembly 100 may be inserted into the housing 200 through the open lower surface of the housing 200 together with the electrolyte, and then the lower surface of the housing 200 may be blocked (e.g., sealed) by the cover plate 400. The electrolyte may be a non-aqueous organic electrolyte that is a mixture of a lithium salt and a high-purity organic solvent. In other embodiments, the electrolyte may be a polymer using a polymer electrolyte, or may be a solid electrolyte.

[0078] The upper portion and the side portion of the housing 200 may be integrally formed with each other.The housing 200 may be made of, for example, steel, a steel alloy, aluminum, or an aluminum alloy.

[0079] The housing 200 may have a through-hole formed through an upper portion thereof to allow the terminal 700 to be mounted therein.

[0080] The case 200 may have a hemming portion and a crimping portion formed on its side portion. The hemming portion may secure the electrode assembly 100 and provide a seat for the cap plate 400 to sit on, and may be formed by pressing the lower portion of the side portion of the case 200 inwardly. The crimping portion may secure the cap plate 400 and may be formed by bending the lower end of the side portion of the case 200 inwardly to cover the edge of the cap plate 400.

[0081] The first current collector 300 can electrically connect the first electrode plate 110 of the electrode assembly 100 to the housing 200. To this end, the first current collector 300 can be welded to the first electrode uncoated portion of the first electrode plate 110 of the electrode assembly 100 and welded to the housing 200. For example, the first current collector 300 may include a flat portion formed into a shape corresponding to the lower surface of the electrode assembly 100 and an extension portion extending outward and downward from the flat portion. The flat portion may be in contact with the first electrode uncoated portion of the first electrode plate 110 of the electrode assembly 100 and may be fixed and electrically connected to the first electrode uncoated portion by, for example, welding. The extension portion may be in contact with the hemming portion of the housing 200 at its edge and may be fixed and electrically connected to the hemming portion by, for example, welding. The edge of the extension portion may be interposed and fixed between the hemming portion of the housing 200 and the first gasket 500.

[0082] The cap plate 400 may be coupled to the lower surface of the case 200. For example, in a state where the electrode assembly 100 is accommodated in the case 200 (e.g., afterward), the lower portion of the side portion of the case 200 may be concavely pressed inward to form a curling portion, the cap plate 400 may be seated on the curling portion, and the lower end of the side portion of the case 200 may be bent inward to form a crimping portion together with the first gasket 500 to cover the edge of the cap plate 400. In this way, the cap plate 400 may be mounted to the case 200.

[0083] The cover plate 400 may have a notch serving as a safety vent. If gas is generated due to abnormal operation of the secondary battery so that the internal pressure therein reaches a reference (e.g., predetermined) pressure or more, the cover plate 400 may be cut (e.g., burst) along the notch due to the pressure to open, thereby discharging the gas and thus preventing the secondary battery from exploding.

[0084] The first gasket 500 may be provided between the case 200 and the cap plate 400 and may prevent the electrolyte from leaking to the outside or foreign matter (e.g., moisture or dust) from being introduced into the case 200. The first gasket 500 may be made of, for example, polypropylene (PP), polyethylene (PE), ethylene propylene diene monomer (EPDM), or nitrile butadiene rubber (NBR).

[0085] The second current collector 600 may be disposed between the second electrode plate 130 of the electrode assembly 100 and the terminal 700, and may electrically connect the second electrode plate 130 to the terminal 700. To this end, the second current collector 600 may be formed into a shape corresponding to the upper surface of the electrode assembly 100. One side of the second current collector 600 may be in contact with the second electrode uncoated portion of the second electrode plate 130 of the electrode assembly 100 and may be fixed and electrically connected to the second electrode uncoated portion by, for example, welding, and the opposite side of the second current collector 600 may be in contact with the terminal 700 and may be fixed and electrically connected to the terminal 700 by, for example, welding. The second current collector 600 may be made of, for example, aluminum.

[0086] The terminal 700 can be installed in a through-hole formed through the upper portion of the housing 200. For example, the terminal 700 can be installed in a riveted manner (for example, the terminal 700 can be a rivet and / or can be riveted to the housing 200). For example, the terminal 700 can be inserted into the through-hole from the outside of the housing 200, and then, the portion of the terminal 700 inserted into the housing 200 (for example, the inner portion) can be deformed to have a diameter larger than the through-hole so as to be supported and fixed by the inner surface of the upper portion of the housing 200. In such an embodiment, the portion of the terminal 700 located outside the housing 200 can be formed to have a diameter larger than the through-hole, so that it can be supported by the outer surface of the upper portion of the housing 200. In other embodiments, the terminal 700 can be inserted into the through-hole from the inside of the housing 200, and then, the portion of the terminal 700 protruding to the outside can be deformed to have a diameter larger than the through-hole, so that it can be supported and fixed by the outer surface of the upper portion of the housing 200. In such an embodiment, a portion of the terminal 700 located in the housing 200 (eg, an inner portion) may be formed to have a larger diameter than the through hole and thus may be supported by the inner surface of the upper portion of the housing 200 .

[0087] An inner portion of the terminal 700 may be welded to the second current collector 600 .

[0088] The second gasket 800 may be provided between the housing 200 and the terminal 700, and may electrically insulate the housing 200 and the terminal 700 from each other, and prevent the electrolyte from leaking to the outside or foreign matter (e.g., moisture or dust) from being introduced into the housing 200. The second gasket 800 may be made of, for example, PP, PE, or PET.

[0089] As described above, the cylindrical secondary battery is only one example of various types of secondary batteries that can be constructed using the electrode assembly 100 as described herein, and those skilled in the art may apply the electrode assembly 100 to various types of secondary batteries.

[0090] For example, with Figure 5 Unlike the secondary battery shown in FIG, according to another embodiment, the cap plate 400 may be directly welded to the case 200 instead of being fixed by the crimping portion and the press-fitting portion of the case 200.

[0091] Figure 6 is a schematic diagram of a secondary battery including an electrode assembly 100 according to another embodiment.

[0092] Figure 6 The configuration of the electrode assembly 100 shown in FIG. 1 is the same as that described above, and thus a repeated description thereof will be omitted.

[0093] The case 200' can accommodate the electrode assembly 100 and the electrolyte, and can define the appearance of the secondary battery together with the cap assembly 300'. The case 200' can have a body portion 210' having a substantially cylindrical shape and a bottom portion 220' connected to one side of the body portion 210'. The case 200' can have a curling portion 211' as an inwardly deformed portion of the body portion 210' and a crimping portion 212' bent inwardly at the end portion of the opening in the body portion 210'.

[0094] The crimping portion 211' can inhibit movement of the electrode assembly 100 in the case 200' and facilitate the seating of the gasket 400' and the cap assembly 300'. The crimping portion 212' can press the edge of the cap assembly 300' through the gasket 400' to securely secure the cap assembly 300' to the case 200'. The case 200' can be made of, for example, nickel-plated steel.

[0095] The cover assembly 300' can be fixed to the inner side of the crimping portion 212' via the gasket 400' to seal the housing 200'. The cover assembly 300' can include an upper cover 310', a safety vent 320', a lower cover 330', an insulating member 340', and a sub-plate 350'. However, the embodiment is not limited thereto. The cover assembly 300' can be modified to have any of various other suitable configurations.

[0096] The upper cover 310' may be located (or may form) the highest position in the cap assembly 300'. The upper cover 310' may include a terminal portion protruding upwardly and outwardly to connect to an external circuit, and may have a discharge hole around the terminal portion for discharging gas.

[0097] The safety vent 320' may be located below the upper cover 310'. The safety vent 320' may have a protruding portion protruding downwardly and outwardly to be connected to the sub-board 350' and at least one notch located around the protruding portion.

[0098] If gas is generated due to overcharging or abnormal operation of the secondary battery, the protruding portion of the safety vent 320' may be deformed upward due to pressure and may be separated from the sub-plate 350', and the safety vent 320' may be cut along the notch (for example, the safety vent 320' may burst). The cut safety vent 320' can discharge the gas to the outside, thereby preventing the explosion of the secondary battery.

[0099] The lower cover 330' may be located below the safety vent 320'. The lower cover 330' may have an exposure opening through which the protruding portion of the safety vent 320' is exposed, and a gas discharge opening for discharging gas. An insulating member 340' may be located between the safety vent 320' and the lower cover 330' to insulate the safety vent 320' and the lower cover 330' from each other.

[0100] The sub-plate 350' can be located below the lower cover 330'. The sub-plate 350' can be fixed to the lower surface of the lower cover 330' to block the exposed opening in the lower cover 330', and the protruding portion of the safety vent 320' can be fixed to the sub-plate 350'. The first lead tab 500' leading out (or extending) from the electrode assembly 100 can be fixed to the sub-plate 350'. Therefore, the upper cover 310', the safety vent 320', the lower cover 330' and the sub-plate 350' can be electrically connected to the first electrode of the electrode assembly 100.

[0101] The first insulating plate 600' may be located below the curling portion 211' to contact the electrode assembly 100, and the first insulating plate 600' may have a tab opening through which the first lead tab 500' is led out. The cap assembly 300' is electrically connected to the first electrode via the first lead tab 500' and may face the electrode assembly 100 with the first insulating plate 600' interposed therebetween. The first insulating plate 600' may maintain insulation between the cap assembly 300' and the electrode assembly 100.

[0102] A second lead tab 700 ′ drawn from the second electrode of the electrode assembly 100 (or extending from the electrode assembly 100 ) may be electrically connected and fixed to the case 200 ′ (eg, fixed to the bottom portion 220 ′ of the case 200 ′).

[0103] The second insulating plate 800' may be located between the electrode assembly 100 and the bottom portion 220' of the case 200', and the second insulating plate 800' may have a tab opening through which the second lead tab 700' is led out. The bottom portion 220' of the case 200' is electrically connected to the second electrode via the second lead tab 700' and may face the electrode assembly 100 with the second insulating plate 800' interposed therebetween. The second insulating plate 800' may maintain insulation between the bottom portion 220' of the case 200' and the electrode assembly 100.

[0104] As apparent from the above description, according to the embodiments of the present disclosure, in the wound-type electrode assembly, since the first electrode substrate, the first separator, and the second separator extend at least one turn (e.g., approximately 360°) beyond the point corresponding to the distal end of the second electrode plate, the electrode assembly can be completely surrounded and protected by the first electrode substrate and the first separator and the second separator in its peripheral region. Therefore, even when the electrode plate expands during charge / discharge, the first electrode active material layer and the second electrode active material layer located on the opposite inner sides of the electrode assembly are not cracked.

[0105] Furthermore, since heat or shock applied from the outside is absorbed by the first electrode substrate and the first and second separators, safety can be improved. Furthermore, since the first and second separators can be impregnated with electrolyte in the peripheral areas, a channel for electrolyte movement can be provided, thereby preventing electrolyte from accumulating in the peripheral areas.

[0106] The above detailed description only describes some embodiments of the electrode assembly and the secondary battery including the electrode assembly according to the present disclosure, and the present disclosure is not limited to the above embodiments. It should be understood by those skilled in the art that various modifications can be made without departing from the spirit of the present disclosure as claimed in the claims and their equivalents.

Claims

1. An electrode assembly comprising: The first electrode plate comprises a first electrode substrate having a first electrode active material layer thereon; first diaphragm; A second electrode plate includes a second electrode substrate having a second electrode active material layer thereon; as well as The second diaphragm, wherein the first electrode plate, the first separator, the second electrode plate, and the second separator are sequentially stacked and wound around a winding axis, and The first electrode substrate, the first separator and the second separator extend beyond the distal end of the second electrode plate by at least one turn in the wound electrode assembly. 2 . The electrode assembly according to claim 1 , wherein the first electrode substrate, the first diaphragm, and the second diaphragm extend beyond the distal end of the second electrode plate by 1 to 1.5 turns. 3 . The electrode assembly according to claim 1 , wherein the first electrode substrate, the first separator, and the second separator extend beyond the distal end of the second electrode plate by 360° to 540°. 4 . The electrode assembly of claim 1 , wherein the first electrode substrate extends beyond distal ends of both the first and second separators. 5 . The electrode assembly of claim 1 , wherein the first electrode substrate extends less than 0.5 turns beyond distal ends of both the first and second separators. The electrode assembly of claim 1 , wherein the first electrode substrate extends less than 180° beyond distal ends of both the first and second separators. 7 . The electrode assembly according to claim 1 , wherein a distal end of the second electrode active material layer coincides with a distal end of the second electrode substrate. 8 . The electrode assembly according to claim 1 , wherein a distal end of the first electrode active material layer overlaps with a distal end of the second electrode active material layer. 9 . The electrode assembly according to claim 1 , wherein the first electrode active material layer extends beyond the distal end of the second electrode plate by 5 mm to 15 mm. 10 . The electrode assembly according to claim 1 , wherein the second electrode active material layer is on both surfaces of the second electrode substrate.

11. The electrode assembly according to claim 1, wherein the first electrode active material layer is on both surfaces of the first electrode substrate, and In the last circle section of the first electrode active material layer, the first electrode active material layer is only on one surface of the first electrode substrate facing the interior of the electrode assembly.

12. The electrode assembly according to claim 1, wherein the first electrode active material layer is on both surfaces of the first electrode substrate, and In the last 360° section of the first electrode active material layer, the first electrode active material layer is only on one surface of the first electrode substrate facing the interior of the electrode assembly. 13 . The electrode assembly of claim 1 , wherein a distal end of the first diaphragm coincides with a distal end of the second diaphragm.

14. The electrode assembly according to claim 1, wherein In a portion of the electrode assembly, when viewed in a longitudinal cross-section passing through the winding axis and the distal ends of both the first and second separators, the first electrode substrate, the first separator, the second separator, and the first electrode substrate are arranged sequentially in this order from the outside of the electrode assembly. 15 . The electrode assembly of claim 1 , wherein the second electrode plate is surrounded by the first electrode substrate, the first separator, and the second separator. 16 . The electrode assembly according to claim 1 , wherein an outer peripheral surface of the electrode assembly is surrounded by the first electrode substrate. 17 . The electrode assembly of claim 1 , further comprising a terminating tape for fixing a distal end of the first electrode substrate.

18. The electrode assembly of claim 17, wherein the terminating tape comprises polyethylene terephthalate. 19 . The electrode assembly of claim 17 , wherein the terminating tape has a thickness in the range of 15 μm to 20 μm.

20. A secondary battery comprising: The electrode assembly according to any one of claims 1 to 19; a housing accommodating the electrode assembly and electrically connected to the first electrode plate of the electrode assembly; a cover coupled to the housing; as well as A terminal is electrically connected to the second electrode plate of the electrode assembly.

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