Electrode, electrode assembly, and rechargeable battery including the same

Abstract

An electrode, an electrode assembly, and a rechargeable battery including the electrode assembly are disclosed. A rechargeable battery electrode includes: a substrate including a first region and a second region; and an active material layer on the substrate, the active material layer including a first portion on the first region and a second portion on the second region, and a thickness of the first portion is greater than a thickness of the second portion.

Description

Technical Field

[0001] The present disclosure relates to an electrode, and more particularly, to an electrode for a rechargeable (or secondary) battery, an electrode assembly, and a rechargeable battery including the electrode assembly. Background Art

[0002] Unlike primary batteries, rechargeable (or secondary) batteries can be repeatedly charged and discharged. Small-capacity rechargeable batteries can be used in portable electronic devices such as mobile phones, notebook computers, and video cameras. Large-capacity and high-density rechargeable batteries can be used as power sources or energy storage for motor drives in hybrid and electric vehicles.

[0003] Such a rechargeable battery can be manufactured by sealing an electrode assembly together with an electrolyte in a housing. The electrode assembly can have a structure in which a positive electrode, a separator, and a negative electrode are stacked. The positive electrode and the negative electrode can be formed by continuously coating an active material on a long strip substrate to form an active material layer and then winding it to produce a core-shaped electrode assembly, or a stacked electrode assembly can be manufactured by stacking sheet-shaped electrodes cut to a certain length. Summary of the invention

[0004] An exemplary embodiment of the present disclosure provides a rechargeable battery electrode, comprising: a substrate including a first region and a second region; and an active material layer on the substrate, the active material layer including a first portion on the first region and a second portion on the second region, and a thickness of the first portion is greater than a thickness of the second portion.

[0005] The active material layer may include an upper active material layer on the first surface of the substrate and a lower active material layer on the second surface of the substrate, the lower active material layer and the upper active material layer being symmetrical with respect to the substrate.

[0006] The substrate may have an uncoated region where the active material layer is not formed, and the second portion may be located between the first portion and the uncoated region.

[0007] The thickness of the second portion may gradually decrease as it moves away from the first portion.

[0008] The second portion may have a multi-stage structure including a plurality of portions having different thicknesses.

[0009] The active material layer may include an upper active material layer on a first surface of a substrate and a lower active material layer on a second surface of the substrate, the first portion may include a first region of the lower active material layer and a first region of the upper active material layer overlapping each other, and the second portion may include a pair of second regions of the upper active material layer on opposite sides of the first region of the upper active material layer, and the second portion does not include the lower active material layer.

[0010] The first portion may include a first region of the upper active material layer on the first surface of the substrate and a lower active material layer on the second surface of the substrate, and the second portion may include a second region of the upper active material layer.

[0011] The first region of the upper active material layer and the second region of the upper active material layer may be integrated with each other and have the same thickness.

[0012] The second region of the upper active material layer may extend beyond the lower active material layer.

[0013] The second region of the upper active material layer may extend beyond the boundary of the lower active material layer by more than 3 mm.

[0014] The first portion may include a first region of an upper active material layer on a first surface of the substrate and a first region of a lower active material layer on a second surface of the substrate, the first region of the upper active material layer overlapping the first region of the lower active material layer, and the second portion may include a second region of the upper active material layer that does not overlap with the lower active material layer and a second region of the lower active material layer that does not overlap with the upper active material layer.

[0015] The first region and the second region of the upper active material layer may be integrated with each other and have the same thickness, and the first region and the second region of the lower active material layer may be integrated with each other and have the same thickness.

[0016] The density of the first portion after pressurization may be greater than the density of the second portion.

[0017] An electrode assembly includes: a first electrode having a structure of a rechargeable battery electrode; a second electrode having a polarity opposite to that of the first electrode and having a structure of a rechargeable battery electrode; and a separator between the first electrode and the second electrode, the separator being wound with the first electrode and the second electrode in an overlapping state.

[0018] A rechargeable battery includes: an electrode assembly; a case accommodating the electrode assembly and an electrolyte; and a cap assembly configured to seal the case.

[0019] Another exemplary embodiment of the present disclosure provides a method for manufacturing a rechargeable battery electrode, comprising: providing a substrate including a first region and a second region; forming an active material layer on the substrate, so that the active material layer includes a first portion on the first region and a second portion on the second region, and a thickness of the first portion is greater than a thickness of the second portion; and pressurizing the first portion of the active material layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Various features will become apparent to those skilled in the art by describing in detail exemplary embodiments with reference to the accompanying drawings, in which:

[0021] Figure 1 A schematic cross-sectional view illustrating an electrode according to an embodiment.

[0022] Figure 2 to Figure 4 A diagram illustrating various stages in a process of manufacturing an electrode according to an embodiment.

[0023] Figures 5 to 8 A cross-sectional view of an electrode according to another embodiment is illustrated.

[0024] Fig. 9 A schematic perspective view illustrating a rechargeable battery according to an embodiment.

[0025] Fig.10 Examples along Fig. 9 A cross-sectional view taken along line XX'. DETAILED DESCRIPTION

[0026] Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey exemplary implementations to those skilled in the art.

[0027] In the drawings, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or substrate is referred to as being "on" another layer or substrate, it can be directly on the other layer or substrate, or there may be intervening layers or substrates. In addition, it will be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there may be one or more intervening layers. Like reference numerals refer to like elements throughout.

[0028] Figure 1 A schematic cross-sectional view illustrating an electrode according to an embodiment.

[0029] like Figure 1 As illustrated in FIG. 1 , an electrode (eg, a rechargeable battery electrode) 700 according to an embodiment of the present disclosure may include a substrate 70 and an active material layer 71 disposed on the substrate 70. For example, Figure 1 As illustrated in FIG. 1 , one active material layer 71 may be on each of two opposite sides of the substrate 70. For example, Figure 1 As further illustrated in FIG. 1 , the active material layer 71 may cover only a portion of the substrate 70 in the longitudinal direction of the substrate 70, so that the active material layer may not be included on the uncoated area D3 at the edge of the substrate 70 (i.e., the substrate 70 may be exposed in the uncoated area D3). For example, the substrate 70 may include a first area and a second area.

[0030] The active material layer 71 may include a first portion D1 and a second portion D2 having different thicknesses. For example, the first portion D1 may be on a first region of the substrate 70, and the second portion D2 may be on a second region of the substrate 70. Figure 1 As illustrated in FIG. 1 , the first portion D1 of the active material layer 71 may be at the center of the active material layer 71, for example, at the center of the active material layer 71 along the longitudinal direction of the active material layer 71. The second portion D2 of the active material layer 71 may be at the edge of the active material layer 71, and may be located, for example, on the opposite side (for example, the opposite edge) of the first portion D1 along the longitudinal direction of the active material layer 71. Figure 1 As illustrated in FIG. 1 , the thickness of the first portion D1 may be greater than the thickness of the second portion D2 (e.g., along a direction perpendicular to the main surface of the active material layer 71). For example, the width of the second portion D2 (e.g., along the longitudinal direction of the active material layer 71) may be greater than 3 mm.

[0031] The thickness of the first portion D1 may be greater than the thickness of the second portion D2, for example, the first portion D1 may extend above the second portion D2 relative to the substrate 70 (for example, extend further than the second portion D2). For example, the second portion D2 may have a thickness of 1 / 3 to 2 / 3 of the thickness of the first portion D1. The active material layer 71 may be squeezed after coating (that is, direct pressure may be mainly applied to the first portion D1 of the active material layer 71, which relatively protrudes above the second portion D2 of the active material layer 71), and therefore, the thickness of the first portion D1 and the second portion D2 may be the same or similar after pressurization. For example, when the first portion D1 having an initially thicker thickness undergoes a pressurization process (for example, a compression process) and has a reduced thickness (for example, a thickness similar to the thickness of the second portion D2) after pressurization, the density of the first portion D1 (after pressurization) may be higher than the density of the second portion D2 due to the compressed structure of the first portion D1.

[0032] In this way, in a case where the edge thickness of the active material layer 71 is relatively thin compared to other parts of the active material layer 71, even if the active material layers formed into multiple rows are pressurized together after the active material is applied by multi-row coating, damage to the substrate 70 due to the difference in elongation can be prevented.

[0033] Figure 2 to Figure 4 A view illustrating a manufacturing process of an electrode according to an embodiment.

[0034] like Figure 2 and Figure 3As illustrated in FIG. 1 , the active material layer 71 may be formed by applying the active material onto the substrate 70 via the coating device 710. The active material layer 71 may be continuously supplied from the coating device 710 onto the substrate 70 via a roller. The active material layer 71 may be formed into a plurality of rows at regular intervals. For example, Figure 1 As illustrated in FIG. 7 , by controlling the discharge amount of the active material through the coating apparatus 710 , the edge (ie, the second portion D2 ) of the active material layer 71 may be formed to have a thin thickness.

[0035] Afterwards, if Figure 4 As illustrated in FIG. 1 , the pressurization process may be performed on multiple rows of active material layers 71 together, for example, all rows of active material layers 71 may be pressurized simultaneously. The pressurization process may be performed using a roller 720, and the roller 720 may pressurize the active material layer 71 by contacting the relatively protruding first portion D1 of the active material layer 71, for example, the roller 720 may pressurize only the first portion D1 of the first portion D1 and the second portion D2 of the active material layer 71.

[0036] In the present case, the pressure transmitted to the first portion D1 may also be transmitted to the second portion D2, but the second portion D2 is not pressed due to not directly contacting the roller 720, and thus a relatively small pressure may be transmitted to the substrate 70. In other words, the pressure directly transmitted from the first portion D1 to the first area of ​​the substrate 70 overlapping the first portion D1 may be greater than the pressure indirectly transmitted from the first portion D1 to the second area of ​​the substrate 70 overlapping the second portion D2, thereby generating a gradually decreasing pressure applied to the substrate 70 through the first portion D1 and the second portion D2. Therefore, the pressure applied to the first and second areas of the substrate 70 overlapping the first portion D1 and the second portion D2 and the uncoated area D3 may be sequentially reduced.

[0037] In general, if pressure is uniformly applied to the entire coating area of ​​the substrate overlapping the active material layer (e.g., via the active material layer having a uniform thickness), the elongation difference may increase due to the pressure difference between the uncoated area and the coated area, causing damage to the substrate. In contrast, in an embodiment of the present disclosure, by forming a relatively thin second portion D2 between the uncoated area D3 and the first portion D1, the pressure applied from the coated area to the uncoated area can be gradually reduced, thereby preventing damage to the substrate by reducing the elongation difference caused by the pressure difference between the uncoated area and the coated area.

[0038] Figures 5 to 8 Schematic cross-sectional view of an electrode according to another embodiment is shown. Figures 5 to 8 The electrodes of the embodiment are Figure 1 The electrodes in are substantially the same, so only the different parts will be described in detail.

[0039] See also Figure 5 , an electrode 701 according to another embodiment of the present disclosure may include a substrate 70 and an active material layer 72 disposed on the substrate 70. The active material layer 72 may include a first portion D1 and a second portion D2 having different thicknesses, and the second portion D2 may be formed of a plurality of portions having different thicknesses to form a multi-level structure. Figure 5 As illustrated in FIG. 1 , the first portion D1 may have a uniform thickness and the second portion D2 may have a non-uniform thickness, ie, the second portion D2 may have two different (eg, discontinuous) thicknesses, defining a stepped profile in a cross-sectional view.

[0040] See also Figure 6 According to another embodiment of the present disclosure, an electrode 702 may include a substrate 70 and an active material layer 73 disposed on the substrate 70. The active material layer 73 may include a first portion D1 and a second portion D2 having different thicknesses, and the second portion D2 may be formed to gradually become thinner as it moves away from the first portion D1. Figure 6 As illustrated in FIG. 1 , the first portion D1 may have a uniform thickness, and the second portion D2 may have a non-uniform thickness, that is, the second portion D2 may have a continuously decreasing thickness, defining a slope-shaped profile in a cross-sectional view.

[0041] exist Figure 1 to Figure 6 In the above embodiment, the active material layer is symmetrical about the substrate 70 on the first surface and the second surface (eg, opposite surfaces) of the substrate 70. However, the active material layer may be asymmetrical, as will be described below. Figure 7 and Figure 8 Described in more detail.

[0042] See also Figure 7 According to another embodiment, the electrode 703 may include active material layers 74 and 75 disposed on the substrate 70, and the active material layers 74 and 75 may include a first portion D1 and a second portion D2 having different thicknesses. The different thicknesses of the first portion D1 and the second portion D2 refer to the total combined thickness of the stacked active material layers 74 and 75.

[0043] The active material layers 74 , 75 may include an upper active material layer 74 and a lower active material layer 75 , and a portion having different thicknesses means that the thicknesses are different based on the entire active material layer including the upper active material layer and the lower active material layer.

[0044] That is, the upper active material layer 74 may be formed to have a width different from that of the lower active material layer 75. Therefore, the width W1 of the upper active material layer 74 may be greater than the width W2 of the lower active material layer 75, and thus the upper active material layer 74 may extend beyond the boundary of the lower active material layer 75. The width W1 of the upper active material layer 74 may be greater than the width W2 of the lower active material layer 75 by more than 3 mm. Therefore, for the active material layers 74 and 75, the thickness of the first portion D1 may include the combined thickness of the upper active material layer 74 and the lower active material layer 75, and the thickness of the second portion D2 may include only the thickness of the upper active material layer 74 extending beyond the lower active material layer 75. The thickness of the first portion D1 may be greater than the thickness of the second portion D2. For example, the first portion D1 may include a first region of an upper active material layer 74 on a first surface of the substrate 70 and a lower active material layer 75 on a second surface of the substrate 70, and the second portion D2 may include a second region of the upper active material layer 74, the first region of the upper active material layer 74 and the second region of the upper active material layer 74 may be integral with each other and have the same thickness, and the second region of the upper active material layer 74 may extend beyond the lower active material layer 75.

[0045] See also Figure 8 According to another embodiment, the electrode 704 may include active material layers 76 and 77 disposed on the substrate 70, and the active material layers 76 and 77 may include a first portion D1 and a second portion D2 having different thicknesses. The different thicknesses of the first portion D1 and the second portion D2 refer to the total combined thickness of the stacked active material layers 76 and 77.

[0046] The active material layers 76 and 77 may include an upper active material layer 76 and a lower active material layer 77, and a portion having different thicknesses indicates that the thickness is different based on the entire active material layer including the upper active material layer and the lower active material layer. The upper active material layer 76 and the lower active material layer 77 may be offset from each other, and the width of the offset distance may be 3 mm or more. Therefore, for the active material layers 76 and 77, the thickness of the first portion D1 including the upper active material layer 76 and the lower active material layer 77 may be greater than the thickness of the second portion D2 formed by the upper active material layer 76 or the lower active material layer 77. For example, the first portion D1 may include a first region of the upper active material layer 76 on the first surface of the substrate 70 and a first region of the lower active material layer 77 on the second surface of the substrate 70, the first region of the upper active material layer 76 may overlap with the first region of the lower active material layer 77, and the second portion D2 may include a second region of the upper active material layer 76 that does not overlap with the lower active material layer 77 and a second region of the lower active material layer 77 that does not overlap with the upper active material layer 76. For example, the first and second regions of the upper active material layer 76 may be integrated with each other and may have the same thickness, and the first and second regions of the lower active material layer 77 may be integrated with each other and may have the same thickness.

[0047] like Figure 7 and Figure 8 As exemplified in FIG. 1 , even if the upper active material layer and the lower active material layer are formed to have a uniform thickness, the width of the upper active material layer and the lower active material layer may be Figure 7 Different from the examples in Figure 8 In the case of misalignment illustrated in the example, the reduction can be as follows Figure 1 The damage to the substrate is caused by the difference in elongation due to the pressure applied to the active material layer during pressurization as exemplified in FIG.

[0048] That is, in the case where pressure is applied after coating the active material layer, when the first portion D1 is pressurized by direct contact between the roller and the active material layer in the up and down directions, the first portion D1 can contact one of the upper roller and the lower roller, and thus the pressure applied to the active material layer can be reduced, so that damage to the substrate due to the difference in elongation between the coated areas D1, D2 and the uncoated area D3 does not occur.

[0049] The above electrodes may be used as a positive electrode or a negative electrode of a rechargeable battery and will be described below with reference to the accompanying drawings.

[0050] Fig. 9 A schematic perspective view illustrating a rechargeable battery according to an embodiment, Fig.10 Examples along Fig. 9 A cross-sectional view taken along line XX'.

[0051] See also Fig. 9 and Fig.10 , a rechargeable battery 1000 according to an embodiment of the present disclosure may include an electrode assembly 10 , a case 27 accommodating the electrode assembly 10 , and a cap assembly 30 installed in an opening of the case 27 .

[0052] The electrode assembly 10 may include a positive electrode 11 and a negative electrode 12 stacked sequentially and a separator 13 between the positive electrode 11 and the negative electrode 12. The separator 13 may be disposed between the positive electrode 11 and the negative electrode 12 and insulate them. The electrode assembly 10 may be a core type in which the positive electrode 11 (ie, the first electrode) and the negative electrode 12 (ie, the second electrode) are wound around a winding axis with the separator 13 therebetween and then flattened.

[0053] The separator 13 is a polymer film that allows lithium ions to pass through, and can be made of, for example, polyethylene, polypropylene, polyvinylidene fluoride or a multilayer film of two or more layers thereof, and can be used as a mixed multilayer film, such as a polyethylene / polypropylene two-layer film, a polyethylene / polypropylene / polyethylene three-layer film, a polypropylene / polyethylene / polypropylene three-layer film, etc.

[0054] The positive electrode 11 may have Figures 1 to 8 The structure of any one of the electrodes illustrated in the figure, and may include a first portion and a second portion having different thicknesses. The positive electrode 11 may include an electrode active portion DA1 and an electrode uncoated portion DA2, and the electrode active portion DA1 may include a substrate formed of a thin metal foil and a positive active material layer made of a positive active material on the substrate. The electrode uncoated portion DA2 is a region where the positive active material layer is not formed and the substrate is exposed, and may be a portion extending from the substrate of the electrode active portion DA1.

[0055] like Fig.10 As illustrated in FIG. 1 , the electrode uncoated portion DA2 of the positive electrode 11 may be located at a first side end of the positive electrode 11 along the longitudinal direction of the positive electrode 11. The substrate of the positive electrode 11 may be made of aluminum, and a compound capable of reversibly inserting and extracting lithium (lithiated inserting compound) may be used as a positive electrode active material. For example, at least one of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and a combination thereof may be used. In the positive electrode 11, the content of the positive electrode active material may be 90 wt% to 98 wt% relative to the total weight of the positive electrode active material layer.

[0056] In one embodiment, the positive electrode active material may further include a binder and a conductive material. In this case, the contents of the binder and the conductive material may each be 1 wt % to 5 wt % relative to the total weight of the positive electrode active material layer.

[0057] The binder is used to ensure that the positive electrode active material particles adhere to each other and the positive electrode active material adheres to the positive electrode substrate. Examples of binders can include polymers such as polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene butadiene rubber, acrylated styrene butadiene rubber, epoxy resin, nylon, etc.

[0058] Conductive materials may be used to impart conductivity to the electrodes, and any electronically conductive material that does not cause chemical changes in the battery may be used.

[0059] The negative electrode 12 may have Figures 1 to 8 The negative electrode 12 may include an electrode active portion DB1 and an electrode uncoated portion DB2, and the electrode active portion DB1 may include a substrate formed of a thin metal foil and a negative electrode active material layer (or intermediate layer) made of a negative electrode active material on the substrate. The electrode uncoated portion DB2 is a region where the negative electrode active material layer is not formed and the substrate is exposed, and may be a portion extending from the substrate of the electrode active portion DB1.

[0060] The electrode uncoated portion DB2 of the negative electrode 12 may be located at a second side end of the negative electrode 12 along the longitudinal direction of the negative electrode 12. In the present case, the electrode uncoated portion DA2 of the positive electrode 11 and the electrode uncoated portion DB2 of the negative electrode 12 may be located on opposite sides of the electrode active portions DA1, DB1 (e.g., on opposite sides of the electrode assembly 10).

[0061] In other embodiments, the electrode uncoated portions of the positive electrode and the negative electrode may each have a shape protruding at regular intervals along a direction in which the substrate is wound, or may be located at the end or end of the wound electrode assembly.

[0062] The electrode assembly 10 may be housed in the case 27 together with the electrolyte. The electrolyte may include a non-aqueous organic solvent and a lithium salt. The non-aqueous organic solvent may serve as a medium through which ions participating in an electrochemical reaction of a battery may move.

[0063] Lithium salts are dissolved in organic solvents and used as a lithium ion source in batteries, enabling alkaline lithium rechargeable batteries to operate, and are substances that facilitate the movement of lithium ions between positive and negative electrodes. Representative examples of lithium salts may include those selected from LiPF6, LiBF4, LiSbF6, LiAsF6, LiN(SO2C2F5)2, Li(CF3SO2)2N, LiN(SO3C2F5)2, LiC4F9SO3, LiClO4, LiAlO2, LiAlCl4, LiN(Cx F 2x+1 SO2)(C y F 2y+1 SO2) (wherein each of x and y is a natural number, such as an integer of 1 to 20), LiCl, LiI and LiB(C2O4)2 (lithium bis(oxalatoborate) (LiBOB)) are supported electrolyte salts. The concentration of the lithium salt is preferably in the range of 0.1M to 2.0M. When the concentration of the lithium salt is within the above range, the electrolyte has suitable conductivity and viscosity so as to exhibit excellent electrolyte performance and allow lithium ions to move efficiently.

[0064] The housing 27 may be made of metal (eg, aluminum) and may have a substantially rectangular parallelepiped shape. A first side of the housing 27 may be open, and a cover plate may be mounted on the open side of the housing 27.

[0065] The cap assembly 30 may include a cap plate 31 coupled to the shell 27 to block an opening of the shell 27 , a positive terminal 21 electrically connected to the positive electrode 11 , and a negative terminal 22 electrically connected to the negative electrode 12 , each of the positive terminal 21 and the negative terminal 22 protruding to the outside of the cap plate 31 .

[0066] The cover plate 31 may be formed in the form of an elongated plate extending in one direction and coupled to the opening of the housing 27. The cover plate 31 may have an inlet 32 ​​extending to the inside thereof. The inlet 32 ​​may be used to inject an electrolyte, and a sealing plug 38 may be installed in the inlet 32. In addition, a vent plate 39 having a notch 39a may be installed in the vent hole 34 so that the cover plate 31 may be opened at a predetermined pressure.

[0067] The positive terminal 21 and the negative terminal 22 may be installed to protrude above the cap plate 31 . The positive terminal 21 may be electrically connected to the positive electrode 11 through the current collecting tab 41 , and the negative terminal 22 may be electrically connected to the negative electrode 12 through the current collecting tab 42 .

[0068] The terminal connection member 25 may be installed between the positive terminal 21 and the current collecting tab 41 to electrically connect the positive terminal 21 and the current collecting tab 41. The terminal connection member 25 may be inserted into a hole formed in the positive terminal 21, and its upper end may be fixed to the positive terminal 21 by welding, and its lower end may be fixed to the current collecting tab 41 by welding.

[0069] Between the terminal connection member 25 and the cap plate 31, a gasket 59 for sealing may be inserted into a hole through which the terminal connection member 25 extends, and a lower insulating member 43 into which a lower portion of the terminal connection member 25 is inserted may be installed below the cap plate 31. A connection plate 58 may be installed between the positive terminal 21 and the cap plate 31 to electrically connect them. The terminal connection member 25 may be installed by being inserted into the connection plate 58. Therefore, the cap plate 31 and the case 27 may be charged by the positive electrode 11.

[0070] The terminal connection member 26 may be installed between the negative terminal 22 and the current collecting tab 42 to electrically connect the negative terminal 22 and the current collecting tab 42. The terminal connection member 26 may be inserted into a hole formed in the negative terminal 22, and its upper end may be fixed to the negative terminal 22 by welding, and its lower end may be fixed to the current collecting tab 42 by welding.

[0071] Between the terminal connection member 26 and the cap plate 31, a gasket 59 for sealing may be inserted into a hole through which the terminal connection member 26 extends, and an upper insulating member 54 may be installed to insulate between the negative terminal 22 and the cap plate 31. The terminal connection member 26 may be installed by fitting into the hole of the upper insulating member 54, and the upper insulating member 54 may be formed to surround the end of the negative terminal 22.

[0072] In addition, a lower insulating member 45 may be installed under the cap plate 31 to insulate the negative terminal 22 and the current collecting tab 42 from the cap plate 31 .

[0073] The short circuit hole 37 may be formed in the cap plate 31, and the short circuit member 56 may be installed in the short circuit hole 37. The short circuit member 56 may include a bent portion convexly bent downward in an arc shape and an edge portion located outside the bent portion and fixed to the cap plate 31. The upper insulating member 54 may have a cutout overlapping the short circuit hole 37, and the short circuit member 56 may overlap the negative terminal 22 exposed through the cutout.

[0074] The short-circuit member 56 may be electrically connected to the cap plate 31 and may be deformed when the internal pressure of the rechargeable battery 1000 increases, causing a short circuit between the positive electrode and the negative electrode. In the case where gas is generated in a rechargeable (or secondary) battery due to an abnormal reaction, the internal pressure of the rechargeable battery rises. In the case where the internal pressure of the rechargeable battery becomes higher than a predetermined pressure, the bent portion is deformed to bulge upward, in which case the negative terminal 22 and the short-circuit member 56 contact, causing a short circuit. In order to facilitate the short circuit between the negative terminal 22 and the short-circuit member 56, the negative terminal 22 may further include at least one protrusion protruding toward the short-circuit member 56, and the protrusion may be spaced apart from the short-circuit member 56.

[0075] For example, Fig.10 As illustrated in FIG. 1 , the rechargeable battery may include a rectangular (eg, square) housing. In another example, the rechargeable battery may include a cylindrical housing or a pouch-type housing.

[0076] As a summary and review, in order to improve the productivity of the electrode, a multi-row coating method can be used, in which the active material is coated at regular intervals and then cut to produce multiple electrodes together. Therefore, in the multi-row coating method, the area coated with the active material and the area not coated with the active material are repeatedly positioned.

[0077] Generally, compression can be performed after the active material is applied but before cutting into electrodes. However, due to the difference in elongation between the area coated with the active material and the area not coated with the active material, the electrode may be damaged during compression.

[0078] Attempts have been made to perform a cutting process after applying an active material and then a compression process. However, after each electrode is separated, the compression process may need to be performed separately, and therefore, as the number of electrodes to be compressed increases, productivity may decrease.

[0079] In contrast, an embodiment of the present disclosure provides an electrode for a rechargeable (or secondary) battery, an electrode assembly, and a rechargeable battery including the electrode assembly, which can minimize damage to the electrode plate due to the difference in elongation between the coated area and the uncoated area even when multiple rows of active material layers are compressed without separating each active material layer. That is, in an embodiment of the present disclosure, when the active material layer is formed, even when multiple rows of active material layers are compressed, damage to the electrode plate due to the difference in elongation between the coated area and the uncoated area can be minimized.

[0080] Example embodiments have been disclosed herein, and although specific terms are employed, they are used and interpreted only in a general and descriptive sense and not for limiting purposes. In some cases, it will be apparent to one of ordinary skill in the art at the time of filing this application that the features, characteristics, and / or elements described in conjunction with a particular embodiment may be used alone or in combination with the features, characteristics, and / or elements described in conjunction with other embodiments, unless otherwise specifically stated. Therefore, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the scope of the invention set forth in the claims.

Claims

1. A rechargeable battery electrode comprising: a substrate including a first region and a second region; as well as An active material layer on the substrate includes a first portion on the first region and a second portion on the second region, and a thickness of the first portion is greater than a thickness of the second portion.

2. The rechargeable battery electrode according to claim 1, wherein the active material layer comprises an upper active material layer on the first surface of the substrate and a lower active material layer on the second surface of the substrate, the lower active material layer and the upper active material layer being symmetrical with respect to the substrate.

3. The rechargeable battery electrode according to claim 2, wherein: The substrate has an uncoated area where the active material layer is not formed, and The second portion is located between the first portion and the uncoated area. 4 . The rechargeable battery electrode according to claim 2 , wherein the thickness of the second portion gradually decreases as the second portion moves away from the first portion. 5 . The rechargeable battery electrode of claim 2 , wherein the second portion has a multi-level structure including a plurality of portions having different thicknesses.

6. The rechargeable battery electrode according to claim 1, wherein: The active material layer includes an upper active material layer on the first surface of the substrate and a lower active material layer on the second surface of the substrate, The first portion includes a first region of the lower active material layer and a first region of the upper active material layer overlapping each other, and The second portion includes a pair of second regions of the upper active material layer on opposite sides of the first region of the upper active material layer, and the second portion does not include a lower active material layer.

7. The rechargeable battery electrode according to claim 1, wherein: The first portion includes a first region of an upper active material layer on a first surface of the substrate and a lower active material layer on a second surface of the substrate, and The second portion includes a second region of the upper active material layer. 8 . The rechargeable battery electrode according to claim 7 , wherein the first region of the upper active material layer and the second region of the upper active material layer are integrated with each other and have the same thickness. 9 . The rechargeable battery electrode according to claim 8 , wherein the second region of the upper active material layer extends beyond the lower active material layer. 10 . The rechargeable battery electrode according to claim 8 , wherein the second region of the upper active material layer extends beyond a boundary of the lower active material layer by more than 3 mm.

11. The rechargeable battery electrode according to claim 1, wherein: The first portion includes a first region of an upper active material layer on a first surface of the substrate and a first region of a lower active material layer on a second surface of the substrate, the first region of the upper active material layer overlaps with the first region of the lower active material layer, and The second portion includes a second region of the upper active material layer that does not overlap with the lower active material layer and a second region of the lower active material layer that does not overlap with the upper active material layer.

12. The rechargeable battery electrode according to claim 11, wherein: The first region and the second region of the upper active material layer are integrated with each other and have the same thickness, and The first region and the second region of the lower active material layer are integrated with each other and have the same thickness. 13 . The rechargeable battery electrode of claim 1 , wherein a density of the first portion after pressurization is greater than a density of the second portion.

14. An electrode assembly comprising: A first electrode having the structure of a rechargeable battery electrode according to any one of claims 1 to 13; a second electrode having a polarity opposite to that of the first electrode and having the structure of a rechargeable battery electrode according to any one of claims 1 to 13; as well as A separator is provided between the first electrode and the second electrode, and the separator is wound around the first electrode and the second electrode in an overlapping state.

15. A rechargeable battery comprising: The electrode assembly according to claim 14; A shell, accommodating the electrode assembly and the electrolyte; as well as A cover assembly is configured to seal the housing.

16. A method of manufacturing a rechargeable battery electrode, the method comprising: providing a substrate including a first region and a second region; forming an active material layer on the substrate, such that the active material layer includes a first portion on the first region and a second portion on the second region, the first portion having a thickness greater than that of the second portion; and The first portion of the active material layer is pressurized.

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