Electrode assembly and secondary battery including the same

Abstract

The present invention relates to an electrode assembly and a secondary battery including the same. An electrode assembly according to an embodiment of the present invention may comprise: a positive electrode and a negative electrode; a separator disposed between the positive electrode and the negative electrode; and a plurality of conductive members disposed between the separator and at least one of the positive electrode and the negative electrode. At least one of the positive electrode and the negative electrode may include: a current collector; a first active material layer disposed on an inner surface of the current collector; and a second active material layer disposed on an outer surface of the current collector. The conductive member may include: a first conductive member formed to overlap an end portion of the first active material layer and to form a first conductive path with the current collector; and a second conductive member formed to overlap an end portion of the second active material layer and to form a second conductive path between the current collector and the second active material layer.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2022-0107111, filed on August 25, 2022, which is hereby incorporated by reference in its entirety. Technical Field

[0004] The present invention relates to an electrode assembly and a device including the same, and more particularly, to an electrode assembly capable of improving safety and a secondary battery including the same. Background Art

[0005] Recently, as the demand for portable electronic products such as laptops, camcorders, and mobile phones has rapidly increased, and the development of electric vehicles, energy storage batteries, robots, satellites, etc. has been regularized, a large amount of research has been conducted on secondary batteries used as driving power sources.

[0006] Rechargeable batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries according to the shape of the battery case. The electrode assembly installed inside the battery case is a chargeable and dischargeable power generation device having a structure in which electrodes and separators are stacked.

[0007] When the charge / discharge cycle of a secondary battery including an electrode assembly is repeated, stress caused by expansion and contraction of the electrode may accumulate inside the electrode assembly. If the stress accumulation exceeds a certain limit, deformation of the electrode assembly may occur, resulting in reduced stability and performance defects of the battery. Summary of the invention

[0008] Technical issues

[0009] Embodiments of the present invention provide an electrode assembly capable of improving safety and a secondary battery including the same.

[0010] The objects of the present invention are not limited to the above contents, but other objects not described herein will be clearly understood by those skilled in the art from the following description.

[0011] Technical Solutions

[0012] An electrode assembly according to an embodiment of the present invention may include: a positive electrode and a negative electrode; a separator arranged between the positive electrode and the negative electrode; and a plurality of conductive members arranged between at least one of the positive electrode or the negative electrode and the separator, wherein at least one of the positive electrode and the negative electrode may include: a current collector; a first active material layer arranged on the inner surface of the current collector; a second active material layer arranged on the outer surface of the current collector, wherein the conductive members include: a first conductive member arranged to overlap with an end of the first active material layer, thereby forming a first conductive path together with the current collector; and a second conductive member arranged to overlap with an end of the second active material layer, thereby forming a second conductive path between the current collector and the second active material layer.

[0013] According to an embodiment, an end portion of the first active material layer may be disposed closer to an end portion of the current collector than an end portion of the second active material layer.

[0014] According to an embodiment, a first conductive member may be disposed on an inner surface of the current collector to form a first conductive path between the first active material layer and the current collector, and a second conductive member may be disposed on an outer surface of the current collector to form a second conductive path electrically connected to the first conductive path.

[0015] According to an embodiment, the first and second conductive members may be arranged to be spaced apart from each other on an outer surface of the current collector, and the first and second conductive paths may be electrically connected to each other.

[0016] According to an embodiment, the conductive member may include: a base material layer disposed between the separator and the electrode; and an adhesive conductive layer disposed on the base material layer, the adhesive conductive layer including a first conductive material and attached to the electrode.

[0017] According to an embodiment, the first conductive material may be made of the same material as the current collector and arranged in the form of dots, lines, or patterns.

[0018] According to an embodiment, the first conductive material may include at least one metal powder of Al, Cu, Ni, Au, and Pt.

[0019] According to an embodiment, the base material layer may include at least one of a second conductive material or an insulating material.

[0020] According to an embodiment, at least one of the first conductive member or the second conductive member may be attached between one of the first and second active material layers and the current collector, and the base material layer may include at least one of a polymer or a carbon-based material.

[0021] According to an embodiment, at least one of the first and second conductive members may be attached to the current collector but not to the first and second active material layers, and the base material layer may include at least one of Al, Cu, or fabric.

[0022] According to an embodiment, the first conductive material may be electrically connected to the second conductive material.

[0023] According to an embodiment, the electrode can be divided into: a coated portion, which includes a current collector, a first active material layer, and a second active material layer; and an uncoated portion, which does not include at least one of the first active material layer or the second active material layer and includes a current collector, wherein the uncoated portion of the electrode can be attached to an electrode tab.

[0024] According to an embodiment, at least one of the first conductive member and the second conductive member may be disposed between at least one of both sides of the electrode tab and the current collector.

[0025] According to an embodiment, the electrode assembly may further include a third conductive member disposed on an uncoated portion of the negative electrode and at a position corresponding to a winding finishing end of the positive electrode.

[0026] According to an embodiment, the third conductive member may be arranged on the same plane as at least a portion of the first conductive member.

[0027] According to an embodiment, the first conductive member may be configured to cover a winding end of a first active material layer included in the positive electrode, and the second conductive member may be configured to cover a winding end of a second active material layer included in the negative electrode.

[0028] A secondary battery according to an embodiment of the present invention may include the above-mentioned electrode assembly.

[0029] Beneficial effects

[0030] According to an embodiment of the present invention, a plurality of conductive members arranged on at least one region of the electrode where cracks may occur may be provided. Therefore, even if disconnection occurs in the electrode due to cracks, the electrical connection within the electrode can be maintained by the conductive members to improve battery performance degradation and ensure stability.

[0031] In addition, various effects directly or indirectly determined by the present disclosure can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a perspective view of a secondary battery including an electrode assembly according to a first embodiment of the present invention.

[0033] Figure 2 It's a picture. Figure 1 An exploded perspective view of an electrode assembly in an unfolded state before being wound.

[0034] Figures 3a to 3d It is a diagram showing Figure 2 2 is a cross-sectional view of various examples of negative electrode conductive members and negative electrode tabs attached to the negative electrode as illustrated in FIG.

[0035] Figures 4a to 4c It's a picture. Figure 2 00140 00141 00141 00142 00143 00144 00145 00146 00147 00148 00149 00149 00146 00147 00148 00149 ...9

[0036] Figure 5 is an exploded view illustrating a state in which a positive electrode and a negative electrode are not folded before an electrode assembly according to a second embodiment of the present invention is wound.

[0037] Figures 6a to 6c is a plan view illustrating a state in which a negative electrode and a positive electrode to which at least one electrode tab is attached are not folded before an electrode assembly according to the present invention is wound.

[0038] Figure 7 It is used for Figures 6a to 6c An exploded view illustrating in detail the uncoated portion on the winding center portion shown in FIG. DETAILED DESCRIPTION

[0039] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. However, the present invention can be implemented in several different forms and is not limited or constrained by the following embodiments.

[0040] In order to explain the present invention clearly, the detailed description of the parts not related to the specification or the related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and in this specification, the reference numerals are added to the components in each figure. In this case, the same or similar reference numerals are assigned to the same or similar elements throughout the specification.

[0041] In addition, the terms or words used in the specification and claims should not be restrictively interpreted as ordinary meanings or dictionary-based meanings, but should be interpreted as meanings and concepts consistent with the scope of the present invention based on the principle that the inventor can appropriately define the concepts of the terms in order to best describe and interpret his or her invention.

[0042] Secondary battery including the electrode assembly according to the first embodiment

[0043] Figure 1 is a perspective view of a secondary battery including an electrode assembly according to a first embodiment of the present invention, and Figure 2 It's a picture. Figure 1An exploded perspective view of an electrode assembly in an unfolded state before being wound.

[0044] Reference Figure 1 to Figure 2 , a secondary battery 10 according to an embodiment of the present invention may include an electrode assembly 100 and a battery case 180 .

[0045] The electrode assembly 100 may be accommodated in a battery case 180. The battery case 180 may include a battery can 182 and a cap assembly 181.

[0046] The battery can 182 may include a receiving portion 183 in which the electrode assembly 100 is received. The electrolyte may be injected into the receiving portion 183 so that the electrode assembly 100 is completely immersed in the battery can 182. The upper portion of the battery can 182 may be opened to serve as an inflow channel for the electrode assembly 100. The battery can 182 may include metal. For example, the battery can 182 may include stainless steel.

[0047] Since the battery can 182 accommodates the electrode assembly 100, the battery can 182 may be provided in a shape corresponding to the shape of the electrode assembly 100. For example, the battery can 182 may be provided in a cylindrical shape so as to accommodate the electrode assembly 100 provided in a wound shape.

[0048] The cap assembly 181 may be mounted on the battery can 182 to cover the open upper portion of the battery can 182 and be coupled to the battery can 182. The cap assembly 181 may be provided by sequentially stacking a safety belt, a current blocking element, a positive temperature coefficient (PTC) element, a top cover, etc. The top cover is seated on the uppermost portion of the cap assembly 181 and coupled to the uppermost portion of the cap assembly 181 to transmit current generated in the secondary battery to the outside.

[0049] Either one of the battery can 182 and the cap assembly 181 may be electrically connected to the positive electrode tab 250 of the electrode assembly 100, and the other of the battery can 182 and the cap 181 may be electrically connected to the negative electrode tab 260 of the electrode assembly 100. For example, the cap assembly 181 may be electrically connected to the positive electrode tab 250 by a welding process, and the bottom surface of the battery can 182 may be electrically connected to the negative electrode tab 260 by a welding process. As another example, one of the battery can 182 and the cap assembly 181 may be electrically connected to the positive electrode tab 250 and the negative electrode tab 260.

[0050] The electrode assembly 100 may be a chargeable and dischargeable power generation element. The electrode assembly 100 has a structure in which the electrode 130 and the separator 160 are combined and alternately stacked. The electrode assembly 100 may be arranged in a shape in which the electrode 130 and the separator 160 are alternately combined to be wound. The electrode assembly 100 may have a structure in which its diameter radially expands in proportion to the number of winding rotations. Here, the electrode assembly 100 may be wound into a cylindrical shape around the winding center portion (or central axis) C. For example, the electrode 130 may include a positive electrode 110 and a negative electrode 120, and the separator 160 may include a first separator 140 and a second separator 150. The electrode assembly 100 may be an electrode assembly in the form of a winding, which is wound into a cylindrical shape by stacking the positive electrode 110, the first separator 140, the negative electrode 120 and the second separator 150 sequentially.

[0051] The positive electrode 110 may include: a positive electrode collector 113; a first positive electrode active material layer 111, the first positive electrode active material layer 111 is arranged on the inner surface (e.g., the surface facing the winding center portion C) of the positive electrode collector 113; and a second positive electrode active material layer 112, the second positive electrode active material layer 112 is arranged on the outer surface (e.g., the surface facing the winding outer portion O) 123b of the positive electrode collector 113. The positive electrode 110 may not have a positive electrode uncoated portion on the winding outer portion O. In the winding outer portion O, the positive electrode collector 113 may not protrude further than the first positive electrode active material layer 111 and the second positive electrode active material layer 111.

[0052] For example, the positive electrode current collector 113 may be provided as a foil made of an aluminum material. At least one of the first positive electrode active material layer 111 or the second positive electrode active material layer 112 may include, for example, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or a compound containing at least one of these and a mixture thereof.

[0053] The negative electrode 120 may include: a negative electrode collector 123; a first negative electrode active material layer 121, the first negative electrode active material layer 121 is arranged on the inner surface 123a of the negative electrode collector 123 (for example, the surface facing the winding center portion C); and a second negative electrode active material layer 122, the second negative electrode active material layer 122 is arranged on the outer surface of the negative electrode collector 123 (for example, the surface facing the winding outer portion O). According to the formation positions of the first negative electrode active material layer 121 and the second negative electrode active material layer 122, the negative electrode 120 may be divided into a negative electrode coating portion 125 (or coating portion) and a negative electrode uncoated portion (or uncoated portion). The negative electrode coating portion 125 may be a region on which the first negative electrode active material layer 121 and the second negative electrode active material layer 122 are arranged. The negative electrode uncoated portion 126 may be a region on which at least one of the first negative electrode active material layer 121 or the second negative electrode active material layer 122 is not arranged. At least one negative electrode tab 260 may be fused to the negative electrode collector 123 of the negative electrode uncoated portion 126 by a method such as welding.

[0054] The negative electrode current collector 123 may be, for example, provided as a foil made of a copper (Cu) or nickel (Ni) material. At least one of the first negative electrode active material layer 121 or the second negative electrode active material layer 122 may include, for example, synthetic graphite, lithium metal, lithium alloy, carbon, petroleum coke, activated carbon, graphite, silicon compound, tin compound, titanium compound or alloy thereof. At least one of the first negative electrode active material layer 121 or the second negative electrode active material layer 122 may include, for example, non-graphite SiO (silicon oxide) or SiC (silicon carbide) and the like.

[0055] Since the negative electrode 120 is arranged to surround the positive electrode 110 when winding, the negative electrode 120 may be provided to be longer than the positive electrode 110. In the winding outer portion O of the electrode assembly 100, the first negative electrode active material layer 121 arranged on the inner surface 123a of the negative electrode collector 123 may face the positive electrode 110. On the other hand, the second negative electrode active material layer 122 arranged on the outer surface 123b of the negative electrode collector 123 may not face the positive electrode 110. Therefore, on the winding outer portion O of the electrode assembly, the first negative electrode active material layer 121 may be arranged longer than the second negative electrode active material layer 122. In the winding outer portion O of the electrode assembly, the end (e.g., end end) of the first negative electrode active material layer 121 may be arranged closer to the end (e.g., end end) of the negative electrode collector 123 than the end (e.g., end end) of the second negative electrode active material layer 122.

[0056] The separator 160 may be arranged between the positive electrode 110 and the negative electrode 120 to separate and electrically insulate the positive electrode 110 from the negative electrode 120. The separator 160 may include a first separator 140 and a second separator 150. The first separator 140 may be stacked outside the positive electrode 110 or the negative electrode 120. The second separator 150 may be stacked outside the other of the positive electrode 110 and the negative electrode 120. For example, when the first separator 140 is stacked outside the positive electrode 110, the first separator 140 may be disposed between the second positive electrode active material layer 122 and the first negative electrode active material layer 111. When the second separator 150 is stacked outside the negative electrode 120, the second separator 150 may be arranged between the first positive electrode active material layer 121 and the second negative electrode active material layer 112. When a stack body in which the positive electrode 110 , the first separator 140 , the negative electrode 120 , and the second separator 150 are sequentially stacked is wound, a wound type electrode assembly 110 in which the second separator 150 is disposed on the outermost surface may be provided.

[0057] At least one of the first separator 140 or the second separator 150 may be, for example, a multilayer film made of polyethylene, polypropylene or a combination thereof, or a polymer film for a solid polymer electrolyte or a gel-type polymer electrolyte, such as polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile or polyvinylidene fluoride hexafluoropropylene copolymer.

[0058] The electrode assembly 100 according to the present invention may include a plurality of negative electrode conductive members 200 arranged on at least a portion of a region of the negative electrode 120 where cracks may occur. The negative electrode conductive members 200 may include a first negative electrode conductive member 211, a second negative electrode conductive member 212, and a third negative electrode conductive member 213.

[0059] Figures 3a to 3d It is a diagram showing Figure 2 2 is a cross-sectional view of various examples of negative electrode conductive members and negative electrode tabs attached to the negative electrode as illustrated in FIG.

[0060] Reference Figures 3a to 3d , the plurality of negative electrode conductive members 200 may be attached to the region where cracks and / or disconnection due to the cracks may occur on the negative electrode collector 123. Even if cracks and / or disconnection due to the cracks occur in the negative electrode collector 123, conductive paths I1 and I2 may be formed between the negative electrode coating portion 125 and the negative electrode tab 260 through the plurality of negative electrode conductive members 200 to supply an electrical signal (e.g., current).

[0061] The first negative electrode conductive member 211 may be attached to the negative electrode 120 to overlap with the end end of the first negative electrode active material layer 121 at which the winding is ended. The first negative electrode conductive member 211 may be arranged to cover the step portion caused by the thickness of the first negative electrode active material layer 121 arranged on the inner surface 123a of the negative electrode collector 123. When disconnection due to cracks occurs in the negative electrode collector 123, the first negative electrode conductive member 211 may form a first conductive path I1 that bypasses the disconnected portion of the negative electrode collector 123. The first negative electrode conductive member 211 may form the first conductive path I1 with the negative electrode collector 123. Figure 3a and Figure 3c The first negative electrode conductive member 211 illustrated in FIG. 1 may contact the negative electrode current collector 123 and the first negative electrode active material layer 121 to form a first conductive path I1 between the negative electrode current collector 123 and the first negative electrode active material layer 121 . Figure 3b The first negative conductive member 211 illustrated in FIG. 1 may contact the negative electrode tab 260 and the first negative current collector 123 to form a first conductive path I1 between the negative electrode tab 260 and the first negative current collector 123 . Figure 3d The first negative electrode conductive member 211 illustrated in FIG. 1 may contact one end and the other end of the negative electrode collector 123 to form a first conductive path I1 between the one end and the other end of the negative electrode collector 123 .

[0062] Even if disconnection due to cracks occurs in the negative electrode collector 123 contacting the end end of the first negative electrode active material layer 121 , electrical connection within the negative electrode 120 may be maintained by the first negative electrode conductive member 211 .

[0063] The second negative conductive member 212 may be attached to the negative electrode 120 to overlap with the end of the second negative active material layer 122, at which the winding is completed. The second negative conductive member 212 may be arranged to cover the step portion caused by the thickness of the second negative active material layer 122 arranged on the outer surface 123b of the negative current collector 123. When a disconnection due to a crack occurs in the negative current collector 123, the second negative conductive member 212 may form a second conductive path I2 that bypasses the disconnected portion of the negative current collector 123. The second negative conductive member 212 may contact the negative current collector 123 and the second negative active material layer 122 to form a second conductive path between the negative current collector 123 and the second negative active material layer 122. The second conductive path I2 may be electrically connected to the first conductive path I1. Even if disconnection due to cracks occurs in the negative electrode current collector 123 contacting the end of the second negative electrode active material layer 122 , electrical connection within the negative electrode 120 may be maintained by the second negative electrode conductive member 212 .

[0064] The third negative conductive member 213 may be attached to the negative electrode 120 to overlap with the end of the positive electrode 110 in which the winding of the positive electrode 110 is ended. When disconnection occurs in the negative current collector 123 due to cracks, the third negative conductive member 213 may form a conductive path that bypasses the disconnected portion of the negative current collector 123. Even if disconnection due to cracks occurs in the negative current collector 123 overlapping the positive electrode 110, electrical connection within the negative electrode 120 may be maintained by the third negative conductive member 213.

[0065] As described above, the present invention can maintain the conductivity of the negative electrode collector 123 through the plurality of negative electrode conductive members 211, 212, and 213 to prevent the performance degradation of the battery cell and ensure the stability of the battery cell. In addition, the present invention can stably ensure the conductive path between the negative electrode tab 260 and the negative electrode 120 through the negative electrode conductive members 211, 212, and 213 to prevent the charging and discharging current from being concentrated at the ends of the negative electrode active material layers 211 and 212. Therefore, it is possible to prevent the heat generated during the charging and discharging of the electrode assembly from being concentrated at the ends of the negative electrode active material layers 211 and 212.

[0066] The negative electrode tab 260 may be disposed adjacent to at least one of the plurality of negative electrode conductive members 211, 212, and 213 disposed on the negative electrode uncoated portion 126. Figures 3a to 3d As illustrated in , the negative electrode tab 260 may be attached and fixed to the negative electrode uncoated portion 126 . Figure 3a , Figure 3b and Figure 3d The first negative electrode conductive member 211 shown in FIG. 2 may be arranged to overlap at least a portion of the negative electrode tab 260, or as shown in FIG. Figure 3c As illustrated in FIG. 2 , the first negative conductive member 211 may be disposed to be spaced apart from the negative electrode tab 260 .

[0067] According to an embodiment, the negative electrode tab 260 may be attached to the outer surface 123b of the negative electrode current collector 123, such as Figure 3a. The first negative conductive member 211 may be attached to the inner surface 123a of the negative current collector 123, the inner surface 123a being a plane different from the negative electrode tab 260. The second negative conductive member 212 and the third negative conductive member 213 may be arranged on the outer surface 123b of the negative current collector 123, the outer surface 123b being on the same plane as the negative electrode tab 260. At least a portion of the negative electrode tab 260 may overlap with the first negative conductive member 211 when the negative current collector 123 is located between the negative electrode tab 260 and the first negative conductive member 211. Therefore, since there is no need to provide a separate space for arranging the first negative conductive member 211, the length of the negative current collector 123 can be prevented from increasing.

[0068] According to an embodiment, the negative electrode tab 260 may be attached to the outer surface 123b of the negative electrode current collector 123, such as Figure 3b . The first negative conductive member 211, the second negative conductive member 212, and the third negative conductive member 213 may be attached to the outer surface 123b of the negative current collector 123. At least a portion of the negative tab 260 may be in direct contact with the first negative conductive member 211 to overlap with the first negative conductive member 211. Therefore, since the space occupied by the first negative conductive member 211 is minimized, the increase in the length of the negative current collector 123 may be minimized.

[0069] According to an embodiment, the negative electrode tab 260 may be attached to the inner surface 123a of the negative electrode current collector 123, such as Figure 3c . The second negative conductive member 212 and the third negative conductive member 213 may be attached to the inner surface 123a of the negative current collector 123, the inner surface being a plane different from the negative electrode tab 260. The first negative conductive member 211 may be arranged on the outer surface 123b of the negative current collector 123, the outer surface being on the same plane as the negative electrode tab 260. The first negative conductive member 211 may be arranged to be spaced apart from the negative electrode tab 260 in the winding direction.

[0070] According to an embodiment, the negative electrode tab 260 may be attached to the inner surface 123a of the negative electrode current collector 123, such as Figure 3d The first negative conductive member 211, the second negative conductive member 212, and the third negative conductive member 213 may be attached to the outer surface 123b of the negative current collector 123. At least a portion of the negative tab 260 disposed on a different plane from the first negative conductive member 211 may overlap with the first negative conductive member 211 with the negative current collector 123 located therebetween.

[0071] According to an embodiment, Figure 3b and Figure 3dThe first negative electrode conductive member 211, the second negative electrode conductive member 212, and the third negative electrode conductive member 213 illustrated in the figure can be arranged on the same plane. Therefore, since the process of attaching the first negative electrode conductive member 211, the second negative electrode conductive member 212, and the third negative electrode conductive member 213 is performed at the same time, the attachment process can be simplified and is simple.

[0072] Figures 4a to 4c It's a picture. Figure 2 00140 00141 00141 00142 00143 00144 00145 00146 00147 00148 00149 00149 00146 00147 00148 00149 ...9

[0073] Reference Figures 4a to 4c The conductive member 300 (eg, Figure 2 and Figures 3a to 3d The negative electrode conductive member 211, 212 and 213 of the present invention can be provided in the form of an adhesive tape, which includes a base material layer 310 and an adhesive layer 320. For example, since both the base material layer 310 and the adhesive layer 320 have adhesive properties, the conductive member 300 can be provided in the form of a double-sided adhesive tape. As another example, since the base material layer 310 is non-adhesive and the adhesive layer 320 is adhesive, the conductive member 300 can be provided in the form of a single-sided adhesive tape.

[0074] When the conductive member 300 is attached to the negative electrode 120, the conductive member 300 may be disposed between the negative electrode 120 and the second separator 150. The base material layer 310 of the conductive member 300 may face (or contact) the second separator 150. The adhesive layer 320 of the conductive member 300 may face (or contact) the negative electrode 120.

[0075] When the conductive member 300 is attached to the positive electrode 110, the conductive member 300 may be disposed between the positive electrode 110 and the first separator 140. The base material layer 310 of the conductive member 300 may face the first separator 140 (or be in contact with the first separator 140). The binder layer 320 of the conductive member 300 may face the positive electrode 110 (or be in contact with the positive electrode 110).

[0076] The adhesive layer 320 may include an adhesive material and a first conductive material 321 provided in a powder form to have adhesive properties and conductive properties. The first conductive material 321 provided in the adhesive layer 320 may be provided as follows: Figure 4a In the form of a pattern (e.g., a grid) as shown in Figure 4b In the form of a line as shown in the figure or as Figure 4c. The first conductive material 321 may include at least one metal powder of Al, Cu, Ni, Au, and Pt. The first conductive material 321 may be determined according to the material of the electrode 130 to which the conductive member 300 is attached. For example, when the conductive member 300 is attached to the negative electrode 120, the first conductive material 321 may be made of the same material (e.g., Cu) as the negative electrode current collector 123. When the conductive member 300 is attached to the positive electrode 110, the first conductive material 321 may be made of the same material (e.g., Al) as the positive electrode current collector 113.

[0077] The first conductive material 321 of the conductive member 300 may be electrically connected to the current collectors 113 and 123. When the conductive member 300 is applied to the negative electrode 120, the first conductive material 321 may be electrically connected to the negative electrode current collector 123 and the negative electrode active material layers 121 and 122. Therefore, even if disconnection due to cracks occurs in the negative electrode current collector 123 contacting the end of the first negative electrode active material layer 121, the current in the negative electrode 120 may be maintained by the first conductive material 321 of the conductive member 300.

[0078] The base material layer 310 may be made of at least one of an insulating material or a second conductive material. The base material layer 310 may include an insulating material such as a fabric or / and a polymer, include a second conductive material such as Al, Cu or / and a carbon-based material, or include an insulating material and a second conductive material. For example, when the conductive member 320 is applied to the step portion between the current collectors 113 and 123 and the active material layers 111, 112, 121 and 122, the base material layer 310 may be made of at least one of a polymer and a carbon-based material. When the conductive member 300 is not attached to the active material layers 111, 112, 121 and 122 but is attached to the current collectors 113 and 123, the base material layer 310 may be made of at least one of Al, Cu or a fabric. Since the second conductive material contained in the base material layer 310 is electrically connected to the first conductive material 321, the conductivity of the conductive member 300 can be improved.

[0079] Electrode assembly according to second embodiment

[0080] Figure 5 1 is a view illustrating a state where the positive electrode and the negative electrode are not folded before the electrode assembly according to the second embodiment of the present invention is wound. In addition to the electrode assembly further including a positive electrode conductive member, the electrode assembly according to the second embodiment of the present invention and Figure 1 The electrode assembly according to the first embodiment of the present invention illustrated in FIG. 4 has the same components. Therefore, the detailed description of the same components will follow Figures 1 to 4b Description.

[0081] Reference Figure 5The electrode assembly according to the present invention may include a negative electrode 120, a positive electrode 110, a negative electrode conductive member 210 (eg, Figure 2 A negative electrode conductive member 210) and a positive electrode conductive member 220.

[0082] The negative electrode 120 may include a negative electrode coating portion 125 and a negative electrode non-coating portion 126. The negative electrode coating portion 125 may include a negative electrode current collector (eg, Figure 2 anode current collector 123 in the embodiment of the present invention), a first cathode active material layer (eg, Figure 2 The first negative electrode active material layer 121 and the second negative electrode active material layer (eg, Figure 2 The negative electrode uncoated portion 126 may not include at least one of the first negative electrode active material layer or the second negative electrode active material layer. At least a portion of the negative electrode current collector disposed on the negative electrode uncoated portion 126 may directly face the separator. The negative electrode tab 260 attached to the negative electrode uncoated portion 126 may be arranged to face the winding outer portion O. The negative electrode tab 260 may be arranged to face the negative electrode conductive member 210 (e.g., Figure 2 and Figures 3a to 3d The negative electrode tab 260 may be disposed to be spaced apart from the negative electrode conductive member 210, or may be disposed to overlap at least a portion of the negative electrode conductive member 210.

[0083] The negative electrode conductive member 210 may be provided to cover a step portion between at least one of the first negative electrode active material layer or the second negative electrode active material layer and a negative electrode current collector disposed on the negative electrode non-coated portion 126 .

[0084] The positive electrode 110 may include a positive electrode coating portion 115 and a positive electrode non-coating portion 116. The positive electrode coating portion 115 may include a positive electrode current collector (eg, Figure 2 The positive electrode current collector 113 in the embodiment of the present invention), the first positive electrode active material layer (for example, Figure 2 The first positive electrode active material layer 111 and the second positive electrode active material layer (eg, Figure 2The positive electrode uncoated portion 116 may not include at least one of the first positive electrode active material layer and the second positive electrode active material layer. At least a portion of the positive electrode current collector arranged on the positive electrode uncoated portion 116 may directly face the separator. At least one positive electrode tab 250 may be fused to the positive electrode uncoated portion 116 using a method such as welding. The positive electrode tab 250 attached to the positive electrode uncoated portion 116 may be arranged on one side of the winding center portion C. The positive electrode tab 250 may be arranged adjacent to the positive electrode conductive member 220. The positive electrode tab 250 may be arranged to be spaced apart from the positive electrode conductive member 220, or may be arranged to overlap at least a portion of the positive electrode conductive member 220.

[0085] The positive electrode conductive member 220 may be provided to cover the step portion between at least one of the first positive electrode active material layer and the second positive electrode active material layer and the positive electrode current collector disposed on the positive electrode uncoated portion 116. When disconnection occurs between the positive electrode active material layer and the positive electrode current collector, the positive electrode conductive member 220 may form a conductive path that bypasses the disconnected portion. Therefore, even if disconnection occurs in the positive electrode 110, the electrical connection within the positive electrode 110 may be maintained by the positive electrode conductive member 220.

[0086] Figures 6a to 6c is a plan view illustrating a state in which a negative electrode and a positive electrode to which at least one electrode tab is attached are not folded before an electrode assembly according to the present invention is wound.

[0087] Reference Figures 6a to 6c , a plurality of negative electrode tabs 260 may be attached to the negative electrode 120. One end of the negative electrode tab 260 may be attached and fixed to the negative electrode uncoated portions 621, 622, and 623 (eg, Figure 2 To Figure 3 and Figure 5 The negative electrode uncoated portion 126 in the negative electrode tab 260 may be disposed on the negative electrode conductive member 210 (eg, Figure 2 and Figures 3a to 3d At least one of the negative electrode conductive members 211, 212 and 213 in the embodiment is adjacent to the negative electrode conductive member 211, 212 and 213 in the embodiment.

[0088] At least one positive electrode tab 250 may be attached to the positive electrode 110. The other end of the positive electrode tab 250 may be attached and fixed to the positive electrode uncoated portions 640, 641, and 642 (eg, Figure 2 To Figure 3 and Figure 5The positive electrode uncoated portion 116 in the embodiment of the present invention may be disposed on the positive electrode conductive member 220 disposed on the positive electrode uncoated portions 640, 641, and 642, and one end portion may protrude further than the positive electrode uncoated portions 640, 641, and 642.

[0089] According to an embodiment, the electrode tabs 250 and 260 attached to at least one of the positive electrode 110 and the negative electrode 120 may be disposed at a winding middle portion between a winding center portion C and a winding outer portion O. As shown in FIG.

[0090] For example, Figure 6aAs shown in , a plurality of negative electrode tabs 260 may be attached to the negative electrode 120. The negative electrode 120 may include a negative electrode coating portion 611, a first negative electrode uncoated portion 621 disposed toward the winding center portion C relative to the negative electrode coating portion 611, and a second negative electrode uncoated portion 622 disposed toward the winding outer portion O relative to the negative electrode coating portion 611. The negative electrode tab 260 may be attached to each of the first negative electrode uncoated portion 621 and the second negative electrode uncoated portion 622. Therefore, a signal transmission path may be formed between the negative electrode tab 260 attached to the first negative electrode uncoated portion 621 and the negative electrode coating portion 611 and between the negative electrode tab 260 attached to the second negative electrode uncoated portion 622 and the negative electrode coating portion 611 to supply current in two directions. One positive electrode tab 250 may be attached to the positive electrode 110. The positive electrode 110 may include a positive electrode uncoated portion 640, a first positive electrode coated portion 631 disposed toward a winding center portion C relative to the positive electrode uncoated portion 640, and a second positive electrode uncoated portion 632 disposed toward a winding outer portion O relative to the positive electrode uncoated portion 640. The positive electrode uncoated portion 640 may be disposed at a winding middle portion between the winding center portion C and the winding outer portion O. A signal transmission path may be formed between the positive electrode tab 250 attached to the positive electrode uncoated portion 640 and the first positive electrode coated portion 631 and between the positive electrode tab 250 attached to the positive electrode uncoated portion 640 and the second positive electrode coated portion 632 to supply current in two directions. At least one conductive member 210 and 220 may be attached to each of the positive electrode 110 and the negative electrode 120. In the positive electrode 110, the positive electrode conductive member 220 may be attached to cover a step portion between a positive electrode active material layer provided in at least one of the first positive electrode coating portion 631 and the second positive electrode coating portion 632 and a positive electrode current collector of the positive electrode non-coating portion 640. Therefore, even if cracks or / and disconnection due to the cracks occur in the positive electrode current collector provided in the positive electrode non-coating portion 640, electrical connection between the positive electrode coating portions 631 and 632 and the positive electrode tab 250 may be maintained by the positive electrode conductive member 220. In the negative electrode 120, the negative electrode conductive member 210 may be attached to cover a step portion between each of the first negative electrode non-coating portion 621 and the negative electrode coating portion 610. Therefore, even if cracks or / and disconnection due to the cracks occur in the negative current collector provided in each of the first negative uncoated portion 621 and the second negative uncoated portion 622 , the electrical connection between the negative coating portion 610 and the negative electrode tab 260 can be maintained by the negative conductive member 210 .

[0091] As another example, Figure 6bAs shown in , a plurality of positive electrode tabs 250 may be attached to the positive electrode 110. The positive electrode 110 may include a first positive electrode coating portion to a third positive electrode coating portion 631, 632, and 633 and a first positive electrode uncoated portion 641 and a second positive electrode uncoated portion 642. The first positive electrode coating portion 631 may be arranged to face the winding center portion relative to the third positive electrode coating portion 633. The second positive electrode coating portion 632 may be arranged to face the winding outer portion relative to the third positive electrode coating portion 633. The first positive electrode uncoated portion 641 may be arranged between the first positive electrode coating portion 631 and the third positive electrode coating portion. The second positive electrode uncoated portion 642 may be arranged between the second positive electrode coating portion 632 and the third positive electrode coating portion 633. A signal transmission path may be formed in two directions between each of the first positive electrode coating portion 631 and the third positive electrode coating portion 633 and the positive electrode tab 250 attached to the first positive electrode uncoated portion 641 to supply current in two directions. A signal transmission path may be formed in two directions between each of the second positive electrode coating portion 632 and the third positive electrode coating portion 633 and the positive electrode tab 250 attached to the second positive electrode uncoated portion 642 to supply current in two directions. The positive electrode conductive member 220 may be attached to an area of ​​the positive electrode 110 where there is a risk of disconnection. The positive electrode conductive member 220 may be attached to cover the step portion between the first positive electrode coating portion 631 and the first positive electrode uncoated portion 641, the step portion between the first positive electrode uncoated portion 641 and the second positive electrode coating portion 632, the step portion between the second positive electrode coating portion 632 and the second positive electrode uncoated portion 642, and the step portion between the second positive electrode uncoated portion 642 and the third positive electrode coating portion 633. Therefore, even if cracks or / and disconnection caused by cracks occur in the positive electrode collector, the electrical connection between the positive electrode coating portions 631, 632, and 633 and the positive electrode tab 250 may be maintained by the positive electrode conductive member 220.

[0092] Figure 6b Each of the negative electrode 120, the negative electrode tab 260, and the negative electrode conductive member 210 shown in FIG. Figure 6a Each of the negative electrode 120, the negative electrode tab 260, and the negative electrode conductive member 210 illustrated in FIG. 1 is substantially the same, and therefore, reference will be made to Figure 6a Description.

[0093] As another example, Figure 6c, at least three negative electrode tabs 260 may be attached to the negative electrode 120. The negative electrode 120 may include first to third negative electrode uncoated portions 621, 622, and 623 and a first negative electrode coated portion 611 and a second negative electrode coated portion 612. The first negative electrode uncoated portion 621 may be arranged toward the winding center portion C relative to the third negative electrode uncoated portion 623. The second negative electrode uncoated portion 622 may be arranged toward the winding outer portion O relative to the third negative electrode uncoated portion 623. The first negative electrode coated portion 611 may be arranged between the first negative electrode uncoated portion 621 and the third negative electrode uncoated portion 623. The second negative electrode coated portion 612 may be arranged between the second negative electrode uncoated portion 622 and the third negative electrode uncoated portion 623. A signal transmission path may be formed in two directions between each of the negative electrode tab 260 attached to the first negative electrode uncoated portion 621 and the negative electrode tab 260 attached to the third negative electrode uncoated portion 623 and the first negative electrode coated portion 611 to supply current in two directions. A signal transmission path may be formed in two directions between each of the negative electrode tab 260 attached to the second negative electrode uncoated portion 622 and the negative electrode tab 260 attached to the third negative electrode uncoated portion 623 and the second negative electrode coated portion 612 to supply current in two directions.

[0094] The negative electrode conductive member 210 may be attached to a region of the negative electrode 120 where there is a risk of disconnection. The negative electrode conductive member 210 may be attached to cover a step portion between the first negative electrode coating portion 611 and the first negative electrode uncoated portion 621, a step portion between the first negative electrode coating portion 611 and the third negative electrode uncoated portion 623, a step portion between the third negative electrode uncoated portion 623 and the second negative electrode coating portion 621, and a step portion between the second negative electrode coating portion 621 and the second negative electrode uncoated portion 622. Therefore, even if cracks or / and disconnection due to the cracks occur in the negative electrode current collector, the electrical connection between the negative electrode coating portions 611 and 612 and the negative electrode tab 260 may be maintained by the negative electrode conductive member 210.

[0095] Figure 6c Each of the positive electrode 110, the positive electrode tab 250, and the positive electrode conductive member 220 shown in FIG. Figure 6b Each of the positive electrode 110, the positive electrode tab 250, and the positive electrode conductive member 220 illustrated in FIG. 1 is substantially the same, and therefore, reference will be made to the positive electrode 110, the positive electrode tab 250, and the positive electrode conductive member 220. Figure 6b Description.

[0096] Figure 7 It is used for Figures 6a to 6c An exploded view illustrating in detail the uncoated portion on the winding center portion shown in FIG.

[0097] Reference Figure 7 At least one of the positive and negative electrodes 720 may include a current collector 723 (eg, Figure 2 The negative electrode current collector 113 and the positive electrode current collector 123 in the embodiment of the present invention are provided, and the first active material layer 721 (for example, Figure 2 The first negative electrode active material layer 111 and the first positive electrode active material layer 121 in the collector 720 and the second active material layer 722 (for example, Figure 2 The electrode 720 may include a first coating portion 741 disposed at one side of the uncoated portion 730 and a second coating portion 742 disposed at the other side of the uncoated portion 730.

[0098] The number of the conductive members 700 may be determined according to the end position of each of the first active material layer 721 and the second active material layer 722. For example, the end of the first active material layer 721 and the end of the second active material layer 722 may be arranged on virtual vertical lines different from each other. In this case, cracks caused by the step portion between the first active material layer 721 and the current collector 723 and cracks caused by the step portion between the second active material layer 722 and the current collector 723 may appear at different positions. Therefore, at least two conductive members 710 may be provided to prevent disconnection caused by cracks occurring at different positions. As another example, the end of the first active material layer 721 and the end of the second active material layer 722 may be arranged on the same virtual vertical line. In this case, cracks caused by the step portion between the first active material layer 721 and the current collector 723 and cracks caused by the step portion between the second active material layer 722 and the current collector 723 may appear at the same position. Therefore, at least one conductive member 710 may be provided to prevent disconnection caused by cracks occurring at the same position.

[0099] The conductive member 700 disposed at the winding middle portion may include a plurality of conductive members 701, 702, and 703. For example, the conductive member 710 may include a first conductive member 701, a second conductive member 702, and a third conductive member 703.

[0100] Since two step portions arranged on different virtual vertical lines are formed between the first coating portion 741 and the non-coating portion 742, the first conductive member 701 and the second conductive member 702 may be arranged between the first coating portion 741 and the non-coating portion 730. The first conductive member 701 may be arranged to cover the step portion between the first active material layer 721 disposed on the first coating portion 741 and the current collector 723. The second conductive member 702 may be arranged to cover the step portion between the second active material layer 722 disposed on the first coating portion 741 and the current collector 723.

[0101] Since two step portions arranged on the same virtual vertical line are formed between the second coating portion 742 and the uncoating portion 730, the third conductive member 703 may be arranged between the second coating portion 742 and the uncoating portion 730. The third conductive member 730 may be arranged to cover the step portion between one of the first active material layer 721 and the second active material layer 722 provided on the second coating portion 742 and the current collector 723.

[0102] As described above, even if disconnection due to cracks occurs in the current collector 723 forming a stepped portion with the active material layers 721 and 722, electrical connection within the electrode 720 can be maintained by the conductive member 710. Therefore, the present invention can maintain the conductivity of the electrode 720 by the conductive member 710 to prevent performance degradation of the battery cell and ensure stability of the battery cell.

[0103] The above-mentioned electrode assembly is not limited to the embodiment described in each figure, and the structure described in each figure can be applied in combination. The secondary battery including the electrode assembly according to the present invention can adopt multiple Figures 3a to 3d Any of the negative electrodes shown in the figure, or can be used Figures 3a to 3d The electrode assembly according to the present invention may be a combination of negative electrodes. Figures 4a to 4c Any one of the conductive members shown in , or may be used Figures 4a to 4c A combination of conductive components as shown in FIG. Figures 4a to 4c The conductive member including the base material layer and the adhesive conductive layer according to the present invention as shown in FIG. 1 may be arranged on at least one of the winding center portion, the winding outer portion, and the winding middle portion. The electrode assembly according to the present invention may be formed using Figures 6a to 6c Any positive and negative electrode shown in the figure, or you can use Figures 6a to 6c The combination of the positive electrode and the negative electrode described in. In the electrode assembly according to the present invention, Figure 7The winding core portion described in the embodiment can be applied to various embodiments. The electrode assembly according to the present invention has been described as a structure applied to a cylindrical secondary battery as an example, but this is not limited thereto, and the conductive member according to the present invention can also be applied to a pouch type or prismatic battery.

[0104] The secondary battery including the electrode assembly described above can be applied to various devices. It can be applied to transportation tools such as electric bicycles, electric vehicles, hybrid vehicles, etc., but is not limited thereto, but can be applied to various devices that can use the battery module.

[0105] While embodiments of the present invention have been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

[0106] [Description of Reference Signs]

[0107] 100: Electrode assembly

[0108] 110: Positive

[0109] 120: Negative electrode

[0110] 140: First separator

[0111] 150: Second separator

[0112] 250, 260: electrode tabs

[0113] 210, 220, 701, 702, 703: conductive components.

Claims

1. An electrode assembly, comprising: Positive and negative electrodes; a separator, the separator being arranged between the positive electrode and the negative electrode; as well as a plurality of conductive members disposed between at least one of the positive electrode or the negative electrode and the separator, Wherein, at least one of the positive electrode and the negative electrode comprises: Current collector; a first active material layer disposed on an inner surface of the current collector; a second active material layer disposed on an outer surface of the current collector, Wherein, the conductive component comprises: a first conductive member arranged to overlap an end portion of the first active material layer so as to form a first conductive path together with the current collector; and A second conductive member is arranged to overlap an end portion of the second active material layer so as to form a second conductive path between the current collector and the second active material layer.

2. The electrode assembly according to claim 1, wherein: The end of the first active material layer is arranged closer to an end of the current collector than the end of the second active material layer.

3. The electrode assembly according to claim 1, wherein: The first conductive member is disposed on the inner surface of the current collector to form the first conductive path between the first active material layer and the current collector, and The second conductive member is disposed on the outer surface of the current collector to form the second conductive path electrically connected to the first conductive path.

4. The electrode assembly according to claim 1, wherein: The first conductive member and the second conductive member are arranged to be spaced apart from each other on the outer surface of the current collector, and The first conductive path and the second conductive path are electrically connected to each other.

5. The electrode assembly according to claim 1, wherein: The conductive member comprises: a base material layer disposed between the separator and the electrode; and An adhesive conductive layer is disposed on the base material layer, the adhesive conductive layer comprising a first conductive material and attached to the electrode.

6. The electrode assembly according to claim 5, wherein: The first conductive material is made of the same material as the current collector, and the first conductive material is arranged in the form of dots, lines, or patterns.

7. The electrode assembly according to claim 5, wherein: The first conductive material includes at least one metal powder of aluminum, copper, nickel, gold and platinum.

8. The electrode assembly according to claim 5, wherein: The base material layer includes at least one of a second conductive material or an insulating material.

9. The electrode assembly according to claim 8, wherein: At least one of the first conductive member and the second conductive member is attached between one of the first active material layer and the second active material layer and the current collector, and The base material layer includes at least one of a polymer or a carbon-based material.

10. The electrode assembly according to claim 8, wherein: At least one of the first conductive member and the second conductive member is attached to the current collector but not to the first active material layer and the second active material layer, and The base material layer includes at least one of aluminum, copper or fabric.

11. The electrode assembly according to claim 8, wherein: The first conductive material is electrically connected to the second conductive material.

12. The electrode assembly according to claim 1, wherein: The electrodes are divided into: a coating portion, the coating portion including the current collector, the first active material layer, and the second active material layer; as well as an uncoated portion that does not include at least one of the first active material layer and the second active material layer and includes the current collector, Wherein, the uncoated portion of the electrode is attached with an electrode tab.

13. The electrode assembly according to claim 12, wherein: At least one of the first conductive member and the second conductive member is disposed between at least one of both sides of the electrode tab and the current collector. 14 . The electrode assembly according to claim 12 , further comprising a third conductive member disposed on the uncoated portion of the negative electrode and at a position corresponding to a winding finishing end of the positive electrode.

15. The electrode assembly according to claim 14, wherein: The third conductive member is arranged on the same plane as at least a portion of the first conductive member.

16. The electrode assembly according to claim 1, wherein: The first conductive member is configured to cover a winding end of the first active material layer included in the positive electrode, and The second conductive member is configured to cover a winding finishing end of the second active material layer included in the negative electrode. 17 . A secondary battery comprising the electrode assembly according to claim 1 .

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