Electrode assembly and rechargeable battery including the same

Abstract

The invention relates to an electrode assembly and a rechargeable battery including the same. The electrode assembly includes: a first electrode including a conductive substrate and having a first electrode active portion and a first electrode uncoated portion; a diaphragm; and a second electrode including a conductive substrate and having a second electrode active portion and a second electrode uncoated portion. The first electrode, the separator, and the second electrode are stacked on each other and wound. At least one of the first electrode uncoated portion and the second electrode uncoated portion has a plurality of inclined cutout portions inclined with respect to a longitudinal direction of the electrode assembly. And an interval between adjacent ones of the inclined cutout portions at a front end of the electrode assembly and an interval between adjacent ones of the inclined cutout portions at a rear end of the electrode assembly are different.

Description

Technical Field

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

[0002] With the technological development and demand for mobile devices, the demand for rechargeable batteries as energy sources is increasing.

[0003] Among various rechargeable batteries, a cylindrical rechargeable battery includes an electrode assembly formed by arranging electrodes on both sides of a separator and winding them in the form of a core, a center pin provided in a hollow portion at the center of the electrode assembly, a shell accommodating the electrode assembly, and a cover assembly sealing an open side (or open end) of the shell.

[0004] The electrode assembly of the pole core shape is formed by winding a strip electrode, and the electrode uncoated portion protrudes in the height direction of the electrode assembly at the opposite ends of the electrode assembly. Accordingly, in order to electrically connect the repeatedly wound electrode uncoated portion, the electrode uncoated portion is folded toward the center of the electrode assembly to overlap and then welded.

[0005] However, in the electrode assembly, it is not easy to fold the electrode uncoated portion continuously wound into a cylindrical shape toward the center of the electrode assembly. In addition, since the curvature radius of the electrode uncoated portion adjacent to the center of the electrode assembly (or closer to the center of the electrode assembly) and the curvature radius of the electrode uncoated portion located at the outer edge (or outside) of the electrode assembly are different, it is difficult to fold them equally toward the center. Summary of the invention

[0006] Embodiments of the present disclosure provide a cylindrical electrode assembly and a rechargeable battery including the same, which can be folded toward the inside of the electrode assembly even when an uncoated portion of an electrode that is repeatedly wound has different radii of curvature.

[0007] According to an embodiment of the present disclosure, an electrode assembly includes: a first electrode, including a conductive substrate, and having a first electrode active portion including a first active material layer and a first electrode uncoated portion without the first active material layer; a separator; and a second electrode, including a conductive substrate, and having a second electrode active portion including a second active material layer and a second electrode uncoated portion without the second active material layer. The first electrode, the separator, and the second electrode are stacked and wound with each other. At least one of the first electrode uncoated portion and the second electrode uncoated portion has a plurality of inclined cut portions inclined relative to the length direction of the electrode assembly, and the intervals between adjacent inclined cut portions in the inclined cut portions at the front end of the electrode assembly and the intervals between adjacent inclined cut portions in the inclined cut portions at the rear end of the electrode assembly are different.

[0008] The interval may gradually increase from the front end toward the rear end.

[0009] The interval may be in the range of 1 mm to 4 mm.

[0010] An inclination angle of the inclined cutout portion at the front end and an inclination angle of the inclined cutout portion at the rear end may be different.

[0011] The inclination angle of the inclined cutout portion may be greater than or equal to 45 degrees and less than 90 degrees.

[0012] The inclination angle of the inclined cutout portion may gradually increase from the front end toward the rear end.

[0013] The inclined cut portion may have a depth in the range of 40% to 80% of a height of a corresponding first electrode uncoated portion or the second electrode uncoated portion.

[0014] Each of the first electrode uncoated portion and the second electrode uncoated portion may have a first region having a plurality of small portions with different widths and a second region having a plurality of small portions with the same width, and the first region may be at the front end of the electrode assembly.

[0015] The width of the small portion of the first region may gradually increase away from the front end.

[0016] At least one of the first electrode uncoated portion and the second electrode uncoated portion includes a front end uncoated region, and the front end uncoated region may have a height that increases in multiple stages away from the front end of the electrode assembly.

[0017] The width of each section of the front end uncoated area may be in the range of 45 mm to 55 mm.

[0018] The front uncoated area may have three to six sections.

[0019] Each segment of the leading end uncoated region may be wound to overlap with each other, and ends of the segments of the leading end uncoated region may completely overlap with each other.

[0020] The width of the front uncoated region may be in a range of 10% to 20% of the entire length of the corresponding first active material layer or the second active material layer.

[0021] The leading end uncoated region may be connected to the leading end uncoated region to be closer to the center than the leading end uncoated region, and a height of the leading end uncoated region may be 1 mm or less.

[0022] A sum of a width of the front uncoated region and a width of the foremost uncoated region may be within a range of 20% to 30% of the entire length of the corresponding first active material layer or the second active material layer.

[0023] A maximum height of the front uncoated area may be smaller than a maximum height of a corresponding first electrode uncoated portion or a second electrode uncoated portion.

[0024] The frontmost uncoated area may be connected to at least one of the first electrode uncoated portion and the second electrode uncoated portion, and connected to be closer to the center than the first electrode uncoated portion or the second electrode uncoated portion, and the height of the frontmost uncoated area may be 1 mm or less.

[0025] The width of the frontmost uncoated region may be in a range of 10% to 20% of the entire length of the corresponding first active material layer or the second active material layer.

[0026] According to another embodiment of the present disclosure, a rechargeable battery includes: the electrode assembly as described above; a cylindrical case accommodating the electrode assembly; a center pin at the center of the electrode assembly; and a cap assembly covering and sealing an opening of the cylindrical case.

[0027] By forming the inclined cutout portion in the electrode uncoated portion, the electrode uncoated portion is easily folded to overlap with other portions of the electrode uncoated portion, thereby facilitating the compacting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a longitudinal cross-sectional view of a rechargeable battery according to an embodiment.

[0029] Figure 2 is a schematic diagram of an electrode assembly according to an embodiment.

[0030] Figure 3 is an expanded view of a portion of an electrode assembly according to an embodiment.

[0031] Figure 4 is an expanded view of a portion of an electrode assembly according to another embodiment.

[0032] Figure 5 and Figure 6 is an expanded view of a portion of an electrode assembly according to other embodiments.

[0033] Figure 7 To include Figure 5 A cross-sectional view of a portion of an electrode assembly showing an uncoated portion of an electrode.

[0034] Figure 8 is a longitudinal sectional view of a rechargeable battery according to another embodiment.

[0035] Description of some reference numerals

[0036] 11: First electrode 12: Separator

[0037] 13: Second electrode 100, 101: Electrode assembly DETAILED DESCRIPTION

[0038] The present description will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the present description are shown. As those skilled in the art will appreciate, the described embodiments may be modified in various different ways, all without departing from the scope of the present description.

[0039] It will be understood that when an element or layer is referred to as being "on," "connected to," or "coupled to" another element or layer, it may be directly on, connected to, or coupled to the other element or layer, or there may also be one or more intervening elements or layers. 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. 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.

[0040] In the drawings, for the sake of illustration, the sizes of various elements, layers, etc. may be enlarged. The same reference numerals refer to the same elements. As used in this article, the term "and / or" includes any and all combinations of one or more related enumerated items. Further, when describing the embodiments of the present disclosure, the use of "may" relates to "one or more embodiments of the present disclosure". Statements such as "at least one of..." and "any one of..." modify the entire element list when following the element list, not the individual elements of the list. For example, the statement "at least one of a, b, and c" means 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 in this article, the term "use" may be considered to be synonymous with the term "utilize". As used in this article, the terms "substantially", "approximately" and similar terms are used as approximate terms, not as degree terms, and are intended to illustrate the inherent variation of measured values ​​or calculated values ​​that will be recognized by those of ordinary skill in the art.

[0041] It will be understood that although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Therefore, the first element, component, region, layer, or section discussed below may be referred to as a second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0042] For ease of description, spatially relative terms (such as "below", "below", "down", "above", "on", etc.) may be used herein to describe the relationship of one element or feature to another element or feature as illustrated in the figure. It will be understood that spatially relative terms are intended to cover different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is turned over, the element described as being "below" or "below" other elements or features will then be oriented as being "above" or "on" other elements or features. Therefore, the term "below" can cover both above and below orientations. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used in this article should be interpreted accordingly.

[0043] 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, the singular form "a" is intended to also include the plural form, unless the context clearly indicates otherwise. It will be further understood that the terms "include" and / or "comprise" specify the presence of the described features, integers, steps, operations, elements and / or parts when used in this specification, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or their groups.

[0044] Figure 1 is a longitudinal cross-sectional view of a rechargeable battery according to an embodiment.

[0045] like Figure 1 As shown, a rechargeable battery according to an embodiment may include: an electrode assembly 100; a case 20 accommodating the electrode assembly 100; a cover assembly 30 coupled to an opening of the case 20 with a gasket interposed therebetween, and the cover assembly 30 electrically connected to the electrode assembly 100; an insulating plate 50 between the cover assembly 30 and the electrode assembly 100; and a center pin 60 disposed at the center of the electrode assembly 100.

[0046] The electrode assembly 100 may include a first electrode 11 , a separator 12 , and a second electrode 13 stacked in sequence. The electrode assembly 100 may be a cylindrical core formed by stacking the first electrode 11 , the separator 12 , and the second electrode 13 and then winding them around a center pin 60 .

[0047] The first electrode 11 may include a conductive substrate (or current collector) formed as a thin metal plate, having a first electrode active portion 11a, where an active material layer (e.g., a transition metal oxide such as LiCoO2, LiNiO2, LiMn2O4, or the like) is formed on both surfaces of the substrate, and a first electrode uncoated portion 11b is formed on the edge of the substrate along the first electrode active portion 11a (or adjacent to the first electrode active portion 11a) and exposes the substrate by not forming an active material layer. The end of the active material layer may be covered by an insulating layer or the like, and the first electrode uncoated portion 11b may be a region where the substrate exists (in some embodiments, the substrate exists together with other layers such as an insulating layer) but the active material layer is not formed.

[0048] The second electrode 13 may include a conductive substrate formed as a thin metal plate, having a second electrode active portion 13a and a second electrode uncoated portion 13b, where an active material layer (e.g., graphite, carbon, or the like) is formed on both surfaces of the substrate, and the second electrode uncoated portion 13b is formed on the edge along the second electrode active portion 13a (or adjacent to the second electrode active portion 13a) and exposes the substrate by not forming the active material layer. The end of the active material layer may be covered by an insulating layer or the like, and the second electrode uncoated portion 12b may be a region where the substrate exists (in some embodiments, the substrate exists together with other layers such as an insulating layer) but the active material layer is not formed.

[0049] In the illustrated embodiment, the first electrode 11 may be a positive electrode, and the second electrode 13 may be a negative electrode. However, in other embodiments, this may be reversed.

[0050] Therefore, in the illustrated embodiment, the substrate of the first electrode 11 may be aluminum (Al), and the substrate of the second electrode 13 may be nickel (Ni), copper (Cu), or an alloy of nickel and copper.

[0051] Figure 2 FIG. 1 is a diagram schematically showing an electrode assembly to describe an uncoated portion of an electrode according to an embodiment. Figure 3 1 is an expanded view of a portion of an electrode assembly for describing an uncoated portion of an electrode according to an embodiment. Figure 4 A portion of an electrode assembly is shown in an unfolded state to illustrate an uncoated portion of an electrode according to another embodiment.

[0052] refer to Figure 2 and Figure 3 , a plurality of inclined cutout portions (eg, inclined cut portions) 7 may be formed in each of the first electrode uncoated portion 11b and the second electrode uncoated portion 13b. Figure 3 and Figure 4 , the inclined cut portion 7 may be formed in the region SS1. The inclined cut portion 7 may be inclined relative to the length direction of the first electrode uncoated portion 11b and the second electrode uncoated portion 13b (may also be referred to as the length direction of the electrode assembly), that is, inclined relative to the winding direction. The inclined cut portion 7 may be formed by using a laser.

[0053] The first electrode uncoated portion 11 b and the second electrode uncoated portion 13 b may be formed symmetrically with respect to an imaginary horizontal center line bisecting the first electrode or the second electrode in the width direction.

[0054] The inclined cutout portion 7 in the first electrode uncoated portion 11b and the second electrode uncoated portion 13b may be inclined at an angle greater than or equal to about 45° and less than about 90°, and in the inclined cutout portion 7, an angle (θ) relative to one side of the electrode active portion 11a, 13a in the length direction may increase from the front end of the first electrode uncoated portion 11b and the second electrode uncoated portion 13b located at the center of the electrode assembly toward the rear end.

[0055] In addition, the intervals P1, P2, P3, P4, ... between adjacent inclined cutout portions 7 in the inclined cutout portions 7 increase from the front end toward the rear end. In the illustrated embodiment, the intervals P1, P2, P3, P4, ... between the inclined cutout portions 7 may increase sequentially from about 1 mm at the front end to about 4 mm at the rear end.

[0056] Accordingly, as the radius of curvature increases away from (or further away from) the center of the electrode assembly, not only the intervals P1, P2, P3, P4... between the inclined cut portions 7 increase, but also the inclination angle θ of the inclined cut portions 7 increases, so that the first electrode uncoated portion 11b and the second electrode uncoated portion 13b can be easily folded toward the center.

[0057] When the electrode uncoated portion separated by a certain number (e.g., a preset or predetermined number) of inclined cutout portions 7 is referred to as a group S1, S2, S3, and S4, the intervals P1, P2, P3, and P4 of the inclined cutout portions 7 formed in each group may be the same. In one embodiment, the first region of the electrode uncoated portion at the front end of the electrode assembly (e.g., the region where the group S1 is located) may have a plurality of small portions of different widths, and the second region of the electrode uncoated portion (e.g., the region where the group S2, S3, or S4 is located) may have a plurality of small portions with the same width. The width of the small portion of the first region (e.g., the region where the group S1 is located) may gradually increase away from the front end.

[0058] In addition, if Figure 4 As shown, the inclination angle of the inclined cutout portion at the front end and the inclination angle of the inclined cutout portion at the rear end may be different from each other. In the illustrated embodiment, the inclination angle may gradually increase from the front end to the rear end.

[0059] For example, when the length of the entire active material layer is divided into three parts A1, A2 and A3, in the first electrode uncoated portion 11b and the second electrode uncoated portion 13b, the first angle θ1 of the inclined cut portion in the first portion A1 adjacent to the front end may be greater than or equal to about 60° and less than about 70°, the second angle θ2 of the inclined cut portion in the second portion A2 may be greater than or equal to about 70° and less than about 80°, and the third angle θ3 of the inclined cut portion in the third portion A3 may be greater than or equal to about 80° and less than about 90°.

[0060] Whenever an inclined cutout portion is formed, the inclination angle may vary, but is not limited thereto, and as Figure 4 As shown, the same inclination angle can be present in each identical group.

[0061] Return to reference Figure 3 , the inclined cutout portion 7 may be formed up to (e.g., may extend to) about 40% to about 80% of the height H of the electrode uncoated portion 11b, 13b, and the inclined cutout portion 7 may be formed at a depth in the range of about 3mm to about 6mm. Therefore, the adjacent portions of the electrode uncoated portion in the cut state are integrally connected without separation, and may be formed to be elongated along the length direction of the active material layer. Therefore, the portion of the electrode uncoated portion within a certain distance (or height) from the active material layer (i.e., about 60% to about 20% of the height H of the electrode uncoated portion) may be connected without forming an inclined cutout portion.

[0062] In one embodiment, in order to prevent a short circuit at the front end further forward than the electrode uncoated portion where the inclined cutout portion 7 is formed, the frontmost uncoated region 11e, 13e located in the region SS0 where the electrode uncoated portion is removed or substantially removed may be formed. The frontmost uncoated region 11e, 13e may be connected to the electrode uncoated portion 11b, 13b, and may be closer to the center than the electrode uncoated portion 11b, 13b. The frontmost uncoated region 11e, 13e is mostly removed in the direction of the height H of the electrode uncoated portion, and the height H0 of the frontmost uncoated region may be retained to be about 1 mm or less. The width of the frontmost uncoated region 11e, 13e (e.g., in the length direction of the active material layer) may be about 10% to about 20% of the entire length of the active material layer of the first electrode or the active material layer of the second electrode.

[0063] By forming the inclined cut portion, after winding, the electrode uncoated portion may be easily folded in the center direction to overlap, and the compacting process and the welding process may be facilitated.

[0064] Return to reference Figure 1, the separator 12 may be provided between the first electrode 11 and the second electrode 13 to insulate them. The separator 12 may be formed of polyethylene, polypropylene, polyvinylidene fluoride, or may be a multilayer including two or more layers thereof, or may be formed of a mixed multilayer such as a polyethylene / polypropylene 2-layer separator, a polyethylene / polypropylene / polyethylene 3-layer separator, or a polypropylene / polyethylene / polypropylene 3-layer separator or the like.

[0065] In the core state, the first electrode current collector 11 d may be connected to the first electrode uncoated portion 11 b of the electrode assembly 100 , and the second electrode current collector 13 d may be connected to the second electrode uncoated portion 13 b of the electrode assembly 100 .

[0066] The second electrode current collector 13d may contact the case 20. The first electrode current collector 11d may be formed to have a narrower width than the second electrode current collector 13d so that the first electrode current collector 11d does not contact the case 20.

[0067] The first electrode uncoated portion 11b of the first electrode 11 may be bent toward the center pin 60, which is the center of the electrode assembly 100, and adjacent portions of the first electrode uncoated portion 11b may be stacked (e.g., stacked on each other) to overlap and be electrically connected to each other. In one embodiment, the first electrode uncoated portion 11b may be easily folded by forming the inclined cutout portion 7.

[0068] The first electrode uncoated portion 11 b may be electrically connected to the first electrode current collector 11 d in an overlapping state.

[0069] The first electrode uncoated portion 11 b has a first surface contacting and electrically connected to the first electrode current collector 11 d and a second surface facing the end of the second electrode 13 and spaced apart from the end of the second electrode 13 .

[0070] An insulating layer may be formed on the second surface of the first electrode uncoated portion 11 b .

[0071] The lead tab 37 may be electrically connected to the first electrode current collector 11 d .

[0072] A first end of the lead tab 37 may be connected to the first electrode current collector 11d by welding, and a second end thereof may be electrically connected to the cap assembly 30. The lead tab 37 may be bent so that one surface thereof faces the cap assembly 30 to increase a contact area therebetween.

[0073] The insulating plate 50 has an opening exposing the center pin 60 , and may be located above the first electrode current collector 11 d .

[0074] The insulating plate 50 may be formed to be larger (e.g., wider) than the first electrode current collector 11d so that the insulating plate 50 may contact the inner surface of the case 20. By forming the insulating plate 50 to be larger than the first electrode current collector 11d, a uniform gap may be formed between the first electrode current collector 11d and the case 20 by the width of the insulating plate 50 protruding outward from the first electrode current collector 11d (e.g., protruding beyond the first electrode current collector 11d). The gap between the first electrode current collector 11d and the case 20 may prevent a short circuit due to contact between the first electrode current collector 11d and the case 20.

[0075] The lead tab 37 may contact the first auxiliary plate 34 of the cap assembly 30 through the opening 51 in the insulating plate 50 and may be connected to the first auxiliary plate 34 , which will be described in more detail later.

[0076] Since the electrode assembly 100 is wound around the center pin 60 , the center pin 60 may be located at the center of the electrode assembly 100 and may be aligned in a direction in which the electrode assembly 100 is inserted into the case 20 .

[0077] The center pin 60 is designed to reduce or minimize deformation when receiving the entire compression load or local impact load acting from the outside of the rechargeable battery, or maintain a shape close to its original shape (e.g., the shape before deformation), and may be in the form of a hollow round tube. In addition, the center pin 60 may be used as a passage for internally generated gas. In some embodiments, the center pin 60 may be omitted.

[0078] The center pin 60 may be formed of a rigid material (e.g., a conductive metal such as steel, steel alloy, aluminum, aluminum alloy, etc.) to minimize deformation against external impact. As such, since the center pin 60 is conductive, both ends of the center pin 60 are installed to maintain an electrically insulated state relative to the first electrode collector 11d and the second electrode collector 13d.

[0079] In some embodiments, an insulating pad 52 is disposed between the lower end of the center pin 60 and the second electrode current collector 13d corresponding thereto. The upper end of the center pin 60 passes through (e.g., extends through) a through hole (e.g., opening) formed in the center of the first electrode current collector 11d in an insulated state, and is supported on the insulating plate 50. In the illustrated embodiment, the upper end of the center pin 60 may be spaced apart from the through hole in the first electrode current collector 11d, and an insulating member may be interposed therebetween. Accordingly, the movement of the center pin 60 in the length direction is restricted, and the center pin 60 may be maintained at the center of the electrode assembly 100 in a stable state.

[0080] The case 20 is open at one side so that the electrode assembly 100 may be inserted therein together with the electrolyte, and may be formed to have substantially the same shape as the core-shaped electrode assembly 100 .

[0081] For example, the housing 20 may have a circular bottom portion and a cylindrical side portion extending a certain length from the bottom portion. During the assembly process of the rechargeable battery, the upper portion of the cylindrical housing may be open. Therefore, during the assembly process of the rechargeable battery, the electrode assembly may be inserted into the cylindrical housing, and then the electrolyte solution may be injected into the cylindrical housing.

[0082] The electrolyte solution allows lithium ions generated by the electrochemical reaction to move between the first electrode and the second electrode inside the battery. The electrolyte solution may contain a lithium salt such as LiPF6 or LiBF4 in an organic solvent such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), or dimethyl carbonate (DMC) (or may consist of a lithium salt in an organic solvent). The electrolyte solution may be in a liquid, solid, or gel state.

[0083] The case 20 may be connected to the second electrode collector 13d of the electrode assembly 100 and may serve as a second electrode terminal of the rechargeable battery. Accordingly, the case 20 may be formed of a conductive metal such as aluminum, aluminum alloy, or nickel-plated steel.

[0084] The cap assembly 30 may be located in the opening of the case 20 and may be coupled to the case 20 with the gasket 40 interposed therebetween. The gasket 40 may insulate the case 20 and the cap assembly 30 from each other and may close and seal the interior of the case 20 accommodating the electrode assembly 100 and the electrolyte solution.

[0085] The cap assembly 30 may include a cap plate 31 , a positive temperature coefficient element 35 , a gas exhaust plate 32 , an insulating member 33 , a first auxiliary plate 34 , and a second auxiliary plate 38 .

[0086] The first auxiliary plate 34 may be electrically connected to the lead tab 37 of the electrode assembly 100 , and may be coupled to the lead tab 37 by welding.

[0087] The second auxiliary plate 38 may be stacked on the first auxiliary plate 34 to be electrically connected to the first auxiliary plate 34, and may be coupled to the first auxiliary plate 34 by welding. The second auxiliary plate 38 may be located at the center of the electrode assembly 100 to correspond to (e.g., align with) the center pin 60, and may have a through hole exposing the first auxiliary plate 34.

[0088] The exhaust plate 32 may be located above the second auxiliary plate 38 with the insulating member 33 interposed therebetween. An edge of the exhaust plate 32 may be inserted into the gasket 40 and may be coupled to the housing 20.

[0089] The exhaust plate 32 may include an exhaust port 32a located in a portion corresponding to the center pin 60. The exhaust port 32a may be formed to protrude from the exhaust plate 32 toward the electrode assembly 100, and may be contacted and electrically connected to the first auxiliary plate 34 through a through hole in the second auxiliary plate 38. The exhaust plate 32 may have a notch 32b surrounding the exhaust port 32a, and the notch 32b guides rupture of the exhaust port 32a if overpressure occurs in the case 20.

[0090] The exhaust port 32a may rupture under a reference (or preset) pressure condition, release the internal gas to the outside and block the electrical connection with the first auxiliary board 34. For example, when the internal pressure of the housing 20 increases due to the generation of gas, the recess 32b may be damaged (e.g., may burst), and the gas may be discharged to the outside through the exhaust hole 31d (which will be described in more detail later), thereby preventing the explosion of the rechargeable battery.

[0091] In addition, if the abnormal reaction continues and the exhaust port 32a is broken, the electrical connection between the exhaust plate 32 and the first auxiliary plate 34 is disconnected. Accordingly, the electrical connection between the first auxiliary plate 34 and the cap plate 31 electrically connected to the exhaust plate 32 is disconnected, and the current is cut off.

[0092] The cap plate 31 may include a center plate 31a corresponding to the center pin 60 at the center of the electrode assembly 100, a plurality of branch portions 31b extending from the center plate 31a toward the gasket 40, and a coupling plate 31c connecting first ends of the branch portions 31b and inserted into and coupled to the gasket 40. Discharge holes 31d opened to the outside and used to discharge internal gas are formed between adjacent branch portions 31b.

[0093] The branch portion 31b is bent from the coupling plate 31c and connected to the central plate 31a, so that the center of the cap plate 31 protrudes away from the case 20. The cap plate 30 may be electrically connected to the first electrode collector 11d through the exhaust plate 32, the second auxiliary plate 38, the first auxiliary plate 34, and the lead tab 37, and may be used as a first electrode terminal of a rechargeable battery. Therefore, when the center of the cap plate 31 is formed to protrude outside the case 20, terminal connection of an external device may be facilitated.

[0094] The positive temperature coefficient element 35 may be formed along the coupling plate 31 c of the cap plate 31 , and may be inserted into and coupled to the gasket 40 in a stacked state between the coupling plate 31 c of the cap plate 31 and an edge of the exhaust plate 32 .

[0095] The positive temperature coefficient element 35 may be installed between the cap plate 31 and the exhaust plate 32 , and may control the flow of current between the cap plate 31 and the exhaust plate 32 according to the internal temperature of the rechargeable battery.

[0096] When the internal temperature is within a reference (or preset) range, the positive temperature coefficient element 35 acts as a conductor to electrically connect the cap plate 31 and the exhaust plate 32. However, when the internal temperature exceeds the reference temperature, the positive temperature coefficient element 35 has a resistance that increases to infinity. Therefore, in some cases, the positive temperature coefficient element 35 may block the flow of charging or discharging current between the cap plate 31 and the exhaust plate 32.

[0097] After the electrode assembly 100 is inserted into the case 20 , the cap assembly 30 is inserted into the gasket 40 while the exhaust plate 32 , the positive temperature coefficient element 35 , and the cap plate 31 are stacked on the edge of the cap assembly 30 and then fitted into the opening of the case 20 .

[0098] Then, the cap assembly 30 is fixed to the opening of the housing 20 by a crimping process. In the illustrated embodiment, the crimping portion 21 and the crimping portion 22 may be formed on one side of the housing 20 adjacent to the opening. The crimping portion 21 may be formed by a crimping process. The crimping portion 21 is a structure or configuration characterized in that it is recessed (or concave) from the upper side of the housing 20 toward the center of the housing 20 in a diameter direction when the electrode assembly 100 is accommodated in the housing 20, and the structure or configuration prevents vertical movement of the electrode assembly 100.

[0099] The crimping portion 22 relatively protrudes more than the crimping portion 21 in a diameter direction, is connected to the crimping portion 21 , and forms upper and lower surfaces connected to the outer circumference of the cap assembly 30 , and the outer circumference is inserted with the gasket 40 .

[0100] Figure 5 and Figure 6 A portion of an electrode assembly is shown in an unfolded state to illustrate an uncoated portion of an electrode according to other embodiments. Figure 7 To include Figure 5 A cross-sectional view of a portion of an electrode assembly showing an uncoated portion of an electrode.

[0101] Figure 5 The first electrode 11 and the second electrode 13 shown in FIG. Figure 3 The first electrode 11 and the second electrode 13 shown in FIG. 1 are substantially the same, and the difference between them will be mainly described in the following description.

[0102] like Figure 5 As shown, according to another embodiment, the first electrode uncoated portion 11b of the first electrode 11 and / or the second electrode uncoated portion 13b of the second electrode 13 includes a second region SS3 having heights H1, H2, and H3 different from the first region SS2 having a uniform height.

[0103] Hereinafter, for better understanding and ease of description, the electrode uncoated portion located in the second region SS3 is referred to as the front end uncoated region 11 c , 13 c .

[0104] The front uncoated area 11c, 13c may be located at the front end of the substrate where winding begins, and its height may increase away from the front end. For example, in order of being away from the front end, it is called the first height H1, the second height H2, and the third height H3, and the height may increase from the first height H1 to the third height H3. The electrode uncoated portion of the second area SS3 may have different heights from the first height H1 to the third height H3, and each portion may be separated by the inclined cut portion 7.

[0105] In the illustrated embodiment, the widths D1, D2, and D3 of the parts (or segments) forming the first height H1, the second height H2, and the third height H3 may be the same, but the present disclosure is not limited thereto. For example, the widths D1, D2, and D3 of the respective parts (or segments) may be in the range of about 45 mm to about 55 mm, and may increase sequentially.

[0106] The above embodiment has been described with an example that the front uncoated area has three different heights, but is not limited thereto. Depending on the height of the uncoated portion of the electrode, it may be formed in three to six sections and may have a width in the range of about 135 mm to about 330 mm.

[0107] The widths D1, D2, and D3 of the front uncoated regions 11c and 13c may be formed to be within a range of about 10% to about 20% of the entire length of the active material layer of the first electrode or the second electrode.

[0108] In one embodiment, the frontmost uncoated areas 11e, 13e (see, e.g. Figure 3 ) may be connected to the front uncoated region 11c, 13c to be closer to the center than the front uncoated region 11c, 13c. When the front uncoated region 11c, 13c is formed together with the frontmost uncoated region 11e, 13e, the sum of the width of the frontmost uncoated region 11e, 13e and the width of the front uncoated region 11c, 13c may be about 20% to about 30% of the entire length of the active material layer of the first electrode or the second electrode.

[0109] In addition, if Figure 6 As shown, an inclined cutout portion may be formed in each portion of the front end uncoated region so that it can be more easily folded during a compacting process of the electrode uncoated portion.

[0110] The front uncoated regions 11c and 13c may be regions to be welded after winding. At this time, the first region SS2 adjacent to the second region SS3 may also be partially welded.

[0111] refer to Figure 7, because a plurality of segments are formed by forming different heights H1 , H2 , and H3 , each portion overlaps when folded toward the center of the electrode assembly, and the electrode uncoated portion forms a multi-layer overlapped structure F.

[0112] As such, when the overlapping structure F is formed, due to the thick thickness, the heat generated during welding can be reduced from being transferred to the inside of the electrode assembly; thereby, the welding strength can be ensured, thereby improving the stability.

[0113] Figure 8 is a longitudinal sectional view of a rechargeable battery according to another embodiment.

[0114] refer to Figure 8 , a rechargeable battery according to an embodiment includes an electrode assembly 101 , a case 20 configured to accommodate the electrode assembly 101 , a first current collector 61 connected to the electrode assembly 101 , a second current collector 62 , an electrode terminal 71 , a gasket 42 , and a liner 41 .

[0115] In the electrode assembly 101, the first electrode 11, the separator 12 and the second electrode 13 overlap, and similarly Figure 1 The embodiment shown in the figure may be in a core state. The first electrode 11 may have a first electrode active portion 11a and a first electrode uncoated portion 11b, where an active material layer is formed on the substrate at the first electrode active portion 11a, and the first electrode uncoated portion 11b exposes the substrate by not forming an active material layer on the substrate. The second electrode 13 may have a second electrode active portion 13a and a second electrode uncoated portion 13b, where an active material layer is formed on both surfaces of the substrate at the second electrode active portion 13a, and the second electrode uncoated portion 13b exposes the substrate by not forming an active material layer on the substrate.

[0116] The first electrode 11 and the second electrode 13 may be, for example, Figures 2 to 6 The electrode of the embodiment shown in FIG. 1 may include an inclined cut portion or a front end formed in multiple stages.

[0117] The first electrode uncoated portion 11b and the second electrode uncoated portion 13b are provided at both ends of the electrode assembly 101 in the winding axis direction (eg, Figure 8 At both ends in the vertical direction in the middle), and in the same direction, electrode terminals 71 and the shell 20 having different polarities may be provided together.

[0118] The exhaust plate 42 may be located on an opposite side of the electrode terminal 71 .

[0119] The case 20 is formed as a cylinder to accommodate the electrode assembly 101, and the electrode terminal 71 and the exhaust plate 42 are respectively provided at both axial ends of the case 20. The electrode terminal 71 is connected to the first electrode 11 through the first current collector 61, and the case 20 is connected to the second electrode 13 through the second current collector 62. In the illustrated embodiment, the exhaust plate 42 is electrically separated (or isolated) from the second current collector 62 and the case 20, and has no polarity (e.g., electrically floating).

[0120] The notch 421 is formed on the inner surface of the exhaust plate 42, and when a rechargeable battery event occurs, the notch 421 is damaged (e.g., burst), thereby reducing the internal pressure and preventing the explosion of the rechargeable battery. The exhaust plate 42 is formed as a circular plate and includes a central portion 422, a convex portion 423, and an outer portion 424.

[0121] The center portion 422 is formed concavely toward the electrode assembly 101, the convex portion 423 is formed convexly outside the center portion 422 in the diameter direction to be away from the electrode assembly 101, and the outer portion 424 is in the same plane with the center portion 422 at the outside of the convex portion 423 in the diameter direction.

[0122] The electrode terminal 71 connected to the first electrode 11 of the electrode assembly 101 and inserted into the case 20 from the outside is installed at one side of the case 20. To this end, the case 20 has a first opening 81 at one side (for example, at one end). The sealing member 211 is provided in the first opening 81 to form an airtight structure with respect to the electrolyte solution by being interposed between the first opening 81 and the electrode terminal 71, and electrically insulates the electrode terminal 71 from the case 20.

[0123] In the illustrated embodiment, the first current collector 61 may be electrically connected to the first electrode uncoated portion 11b and electrically and mechanically connected to the electrode terminal 71. The first current collector 61 contacts most of the first electrode uncoated portion 11b to reduce resistance and is electrically connected to the electrode terminal 71.

[0124] The electrode terminal 71 may be connected to a first side of the first current collector 61 by welding, and may be installed in the first opening 81 of the case 20 by a riveting structure. The electrode terminal 71 may be formed to be more protruding than (e.g., protruding beyond) the outer surface of the case 20 surrounding the first opening 81, and may serve as a positive electrode terminal. In this embodiment, the first current collector 61 is a positive electrode current collector.

[0125] In addition, the case 20 has a second opening 82 so that the second side of the case 20 is completely open so that the electrode assembly 101 can be inserted into the case 20. By inserting the electrode assembly 101 into the case 20 and then sealing the second opening 82 with the gasket 41 surrounding the gasket 42, the gasket 42 can be electrically separated from the case 20.

[0126] In the illustrated embodiment, the second current collector 62 may be electrically connected to the second electrode uncoated portion 13b and to the case 20. The second current collector 62 contacts most of the second electrode uncoated portion 13b to reduce resistance, and is connected to the case 20.

[0127] The exhaust plate 42 can be electrically separated from the second current collector 62 and installed in the second opening 82 in the shell 20 by a crimping process, and the gasket 41 is interposed between them. In the illustrated embodiment, the crimping portion 21 and the crimping portion 22 can be formed on one side adjacent to the second opening 82 of the shell 20. The crimping portion 21 can be formed by a crimping process. The crimping portion 21 is recessed (or concave) from the upper side of the shell 20 toward the center of the shell 20 in the diameter direction, while accommodating the electrode assembly 101 in the shell 20, and can prevent the vertical movement of the electrode assembly 101. The crimping portion 22 is relatively more protruding than the crimping portion 21 in the diameter direction, connected to the crimping portion 21, and has an upper surface and a lower surface connected to the periphery of the exhaust plate 42, and the gasket 40 is inserted.

[0128] While the present disclosure has been described in conjunction with exemplary embodiments, it should be understood that the present disclosure is not limited to the disclosed embodiments, but is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims and their equivalents.

Claims

1. An electrode assembly, comprising: a first electrode including a conductive substrate and having a first electrode active portion including a first active material layer and a first electrode uncoated portion not having the first active material layer; Diaphragm; as well as a second electrode including a conductive substrate and having a second electrode active portion including a second active material layer and a second electrode uncoated portion not having the second active material layer, wherein the first electrode, the separator and the second electrode are stacked and wound on each other, wherein at least one of the first electrode uncoated portion and the second electrode uncoated portion has a plurality of inclined cutout portions inclined relative to a length direction of the electrode assembly, and The intervals between adjacent ones of the inclined cutout portions at the front end of the electrode assembly are different from the intervals between adjacent ones of the inclined cutout portions at the rear end of the electrode assembly. 2 . The electrode assembly according to claim 1 , wherein the interval gradually increases from the front end toward the rear end. 3 . The electrode assembly according to claim 2 , wherein the interval is in the range of 1 mm to 4 mm. 4 . The electrode assembly according to claim 1 , wherein an inclination angle of the inclined cutout portion at the front end and an inclination angle of the inclined cutout portion at the rear end are different. 5 . The electrode assembly according to claim 4 , wherein the inclination angle of the inclined cutout portion is greater than or equal to 45 degrees and less than 90 degrees. 6 . The electrode assembly according to claim 5 , wherein the inclination angle of the inclined cutout portion gradually increases from the front end toward the rear end. 7 . The electrode assembly of claim 1 , wherein the inclined cut portion has a depth in the range of 40% to 80% of a height of the corresponding first electrode uncoated portion or the second electrode uncoated portion.

8. The electrode assembly according to claim 1, wherein each of the first electrode uncoated portion and the second electrode uncoated portion has a first region and a second region, the first region having a plurality of small portions with different widths, the second region having a plurality of small portions with the same width, and The first region is at the front end of the electrode assembly. 9 . The electrode assembly of claim 8 , wherein a width of the small portion of the first region gradually increases away from the front end.

10. The electrode assembly according to claim 1, wherein at least one of the first electrode uncoated portion and the second electrode uncoated portion comprises a front end uncoated region, and The front end uncoated region has a height that increases in multiple stages away from the front end of the electrode assembly. 11 . The electrode assembly according to claim 10 , wherein a width of each section of the front end uncoated area is in the range of 45 mm to 55 mm. 12 . The electrode assembly according to claim 10 , wherein the front end uncoated area has three to six sections.

13. The electrode assembly according to claim 10, wherein each section of the front end uncoated region is wound to overlap each other, and The ends of the segments of the front end uncoated region completely overlap each other. 14 . The electrode assembly according to claim 10 , wherein a width of the front uncoated area is in a range of 10% to 20% of an entire length of the corresponding first active material layer or the second active material layer.

15. The electrode assembly according to claim 14, wherein the frontmost uncoated region is connected to the front uncoated region to be closer to the center than the front uncoated region, and The height of the frontmost uncoated area is 1 mm or less. 16 . The electrode assembly according to claim 15 , wherein the sum of the width of the front uncoated region and the width of the foremost uncoated region is within a range of 20% to 30% of the entire length of the corresponding first active material layer or the second active material layer. 17 . The electrode assembly of claim 10 , wherein a maximum height of the front uncoated area is smaller than a maximum height of a corresponding first electrode uncoated portion or a second electrode uncoated portion.

18. The electrode assembly according to claim 1, wherein the frontmost uncoated region is connected to at least one of the first electrode uncoated portion and the second electrode uncoated portion and is connected closer to the center than the first electrode uncoated portion or the second electrode uncoated portion, and The height of the frontmost uncoated area is 1 mm or less. 19 . The electrode assembly according to claim 18 , wherein a width of the frontmost uncoated region is in a range of 10% to 20% of an entire length of the corresponding first active material layer or the second active material layer.

20. A rechargeable battery comprising: The electrode assembly according to any one of claims 1 to 19; A cylindrical shell, accommodating the electrode assembly; a center pin at the center of the electrode assembly; as well as The cover assembly covers and seals the opening of the cylindrical shell.

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