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 one embodiment of the present invention includes 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 at least one of the positive electrode and the negative electrode and the separator, wherein at least one of the positive electrode and the negative electrode includes 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, and the conductive members may include a first conductive member formed to overlap an end of the first active material layer and forming a first conductive path with the current collector, and a second conductive member formed to overlap an end of the second active material layer and forming a second conductive path between the current collector and the second active material layer.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0107111, filed on August 25, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to an electrode assembly and a device including the same, and more particularly to an electrode assembly capable of improving stability and a secondary battery including the same. [Background technology]

[0003] In recent years, the demand for portable electronic products such as laptops, video cameras, and mobile phones has increased dramatically, and as the development of electric vehicles, energy storage batteries, robots, satellites, and other devices has progressed in earnest, much research has been conducted on secondary batteries used as the driving power source for these products.

[0004] Secondary batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries depending on the shape of the battery case. The electrode assembly attached inside the battery case is a chargeable and dischargeable power generating element consisting of a laminated structure of electrodes and separators.

[0005] When a secondary battery including such an electrode assembly is repeatedly charged and discharged, stress caused by expansion and contraction of the electrodes can accumulate inside the electrode assembly. If the accumulated stress exceeds a certain limit, deformation of the electrode assembly occurs, which can result in a decrease in the stability and performance defects of the battery. Summary of the Invention [Problem to be solved by the invention]

[0006] SUMMARY OF THE INVENTION An object of the present invention is to provide an electrode assembly capable of improving stability and a secondary battery including the same.

[0007] The technical problems of the present invention are not limited to those mentioned above, and other technical problems not mentioned will be apparent to those skilled in the art from the following description. [Means for solving the problem]

[0008] An electrode assembly according to one embodiment of the present invention includes 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 at least one of the positive electrode and the negative electrode and the separator, wherein at least one of the positive electrode and the negative electrode includes 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, and the conductive members may include a first conductive member formed to overlap an end of the first active material layer and forming a first conductive path with the current collector, and a second conductive member formed to overlap an end of the second active material layer and forming a second conductive path between the current collector and the second active material layer.

[0009] According to an embodiment, an end of the first active material layer may be disposed closer to an end of the current collector than an end of the second active material layer.

[0010] According to one embodiment, the first conductive member may be disposed on an inner surface of the current collector and form the first conductive path between the first active material layer and the current collector, and the second conductive member may be disposed on an outer surface of the current collector and form the second conductive path electrically connected to the first conductive path.

[0011] According to one embodiment, the first conductive member and the second conductive member may be spaced apart from each other on an outer surface of the current collector, and the first conductive path and the second conductive path may be electrically connected.

[0012] According to one embodiment, the conductive member may include a substrate layer disposed between the separator and the electrode, and an adhesive conductive layer disposed on the substrate layer, including a first conductive material, and adhering to the electrode.

[0013] According to one embodiment, the first conductive material may be formed of the same material as the current collector and may be arranged in a dot, line, or pattern.

[0014] According to an embodiment, the first conductive material may include metal powder of at least one of Al, Cu, Ni, Au, and Pt.

[0015] According to an embodiment, the base layer may include at least one of a second conductive material and an insulating material.

[0016] According to one embodiment, 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 substrate layer may include at least one of a polymer and a carbon-based material.

[0017] According to one embodiment, at least one of the first conductive member and the second conductive member is attached to the current collector excluding the first active material layer and the second active material layer, and the substrate layer may include at least one of Al, Cu, and fabric.

[0018] According to an embodiment, the first conductive material may be electrically connected to the second conductive material.

[0019] According to one embodiment, the electrode is divided into a coated portion including the current collector, the first active material layer, and the second active material layer, and a plain portion including the current collector and not including at least one of the first active material layer and the second active material layer, and an electrode tab may be attached to the plain portion of the electrode.

[0020] According to one embodiment, at least one of the first conductive member and the second conductive member may be formed between at least one of both sides of the electrode tab and the current collector.

[0021] According to an embodiment, the electrode assembly may further include a third conductive member disposed on the uncoated portion of the negative electrode at a position corresponding to a winding end portion of the positive electrode.

[0022] According to one embodiment, the third conductive member may be disposed on the same plane as at least a portion of the first conductive member.

[0023] According to one embodiment, the first conductive member may be formed to cover a winding terminal end of the first active material layer included in the negative electrode, and the second conductive member may be formed to cover a winding terminal end of the second active material layer included in the negative electrode.

[0024] A secondary battery according to an embodiment of the present invention may include the above-described electrode assembly. [Effects of the Invention]

[0025] According to an embodiment of the present invention, the electrode may include a plurality of conductive members disposed in at least a portion of a region where a crack may occur, thereby maintaining electrical connection within the electrode through the conductive members even if a disconnection due to a crack occurs in the electrode, thereby improving cell performance degradation and ensuring stability.

[0026] In addition, this document can provide various other benefits that can be perceived directly or indirectly. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a perspective view showing a secondary battery including an electrode assembly according to a first embodiment of the present invention; [Figure 2] 2 is an exploded perspective view showing the electrode assembly shown in FIG. 1 in an unfolded state before being wound up. FIG. [Figure 3a] 3A to 3C are cross-sectional views showing various examples of a negative electrode conductive member and a negative electrode tab attached to the negative electrode shown in FIG. 2. [Figure 3b] 3A to 3C are cross-sectional views showing various examples of a negative electrode conductive member and a negative electrode tab attached to the negative electrode shown in FIG. 2. [Figure 3c] 3A to 3C are cross-sectional views showing various examples of a negative electrode conductive member and a negative electrode tab attached to the negative electrode shown in FIG. 2. [Figure 3d] 3A to 3C are cross-sectional views showing various examples of a negative electrode conductive member and a negative electrode tab attached to the negative electrode shown in FIG. 2. [Figure 4a] 3A to 3C are perspective views showing various examples of the conductive member shown in FIG. 2. [Figure 4b] 3A to 3C are perspective views showing various examples of the conductive member shown in FIG. 2. [Figure 4c] 3A to 3C are perspective views showing various examples of the conductive member shown in FIG. 2. [Figure 5] FIG. 10 is an exploded view showing a state in which the positive electrode and the negative electrode are unfolded before the electrode assembly according to the second embodiment of the present invention is wound up. [Figure 6a] 1 is a plan view showing the electrode assembly according to the present invention in a state in which a negative electrode and a positive electrode, each having at least one electrode tab attached thereto, are unfolded before being wound up. [Figure 6b] 1 is a plan view showing the electrode assembly according to the present invention in a state in which a negative electrode and a positive electrode, each having at least one electrode tab attached thereto, are unfolded before being wound up. [Figure 6c] 1 is a plan view showing the electrode assembly according to the present invention in a state in which a negative electrode and a positive electrode, each having at least one electrode tab attached thereto, are unfolded before being wound up. [Figure 7] FIG. 6B is an exploded view for explaining in detail the non-coating portion arranged in the winding intermediate portion shown in FIGS. 6a to 6c. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily understand and practice the preferred embodiments of the present invention. However, the present invention may be embodied in various different forms and is not limited to the following embodiments.

[0029] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the explanation or related known technologies that may unnecessarily obscure the gist of the present invention will be omitted, and in this specification, when assigning reference symbols to components in each drawing, the same or similar reference symbols will be assigned to the same or similar components throughout the specification.

[0030] Furthermore, the terms and words used in this specification and claims should not be interpreted in a limited way to their ordinary or dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, based on the principle that inventors can appropriately define the concepts of terms in order to best explain their inventions.

[0031] Secondary battery including electrode assembly according to the first embodiment FIG. 1 is a perspective view showing a secondary battery including an electrode assembly according to a first embodiment of the present invention, and FIG. 2 is an exploded perspective view showing the electrode assembly shown in FIG. 1 in an unfolded state before being wound up.

[0032] Referring to FIGS. 1 and 2, a secondary battery 10 according to the present invention may include an electrode assembly 100 and a battery case 180.

[0033] The electrode assembly 100 may be housed in the battery case 180. The battery case 180 may include a battery can 182 and a cap assembly 181.

[0034] The battery can 182 may include a receiving portion 183 capable of receiving the electrode assembly 100. An electrolyte may be poured into the receiving portion 183 so that the electrode assembly 100 is completely immersed in the battery can 182. The top of the battery can 182 may be open so that it can be used as an inlet passage for the electrode assembly 100. The battery can 182 may include metal. For example, the battery can 182 may include stainless steel.

[0035] The battery can 182 may be formed in a shape corresponding to the shape of the electrode assembly 100 to accommodate the electrode assembly 100. For example, the battery can 182 may be formed in a cylindrical shape to accommodate the electrode assembly 100 formed in a jelly roll shape.

[0036] The cap assembly 181 may be mounted on the battery can 182 to cover the open top of the battery can 182 and be coupled to the battery can 182. The cap assembly 181 may be formed by sequentially stacking a safety vent, a current interruption device, a PTC (Positive Temperature Coefficient) device, and a top cap. The top cap is mounted on and coupled to the top of the cap assembly 181 to transmit current generated from the secondary battery to the outside.

[0037] 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 assembly 181 may be electrically connected to the negative electrode tab 260. 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.

[0038] The electrode assembly 100 may be a power generating element capable of charging and discharging. The electrode assembly 100 has a structure in which electrodes 130 and separators 160 are assembled and stacked alternately. The electrode assembly 100 may be formed in a wound form in which the electrodes 130 and separators 160 are assembled alternately. The electrode assembly 100 may have a structure in which its diameter expands radially in proportion to the number of winding rotations. In this case, the electrode assembly 100 may be wound into a cylindrical shape wound around a winding center (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 a jelly-roll-shaped electrode assembly in which the positive electrode 110, the first separator 140, the negative electrode 120, and the second separator 150 are sequentially stacked and wound into a cylindrical shape.

[0039] The positive electrode 110 may include a positive electrode current collector 113, a first positive electrode active material layer 111 formed on an inner surface (e.g., a surface facing the winding center (C)) of the positive electrode current collector 113, and a second positive electrode active material layer 112 formed on an outer surface (e.g., a surface facing the winding outer shell portion (O)) 123b of the positive electrode current collector 113. The positive electrode 110 may not have a positive electrode non-coating portion formed on the winding outer shell portion (O). At the winding outer shell portion (O), the positive electrode current collector 113 may not protrude beyond the first positive electrode active material layer 111 and the second positive electrode active material layer 112.

[0040] For example, the positive electrode current collector 113 may be made of an aluminum foil. At least one of the first positive electrode active material layer 111 and the second positive electrode active material layer 112 may be made of, for example, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or a compound or mixture containing one or more of these.

[0041] The negative electrode 120 may include a negative electrode current collector 123, a first negative electrode active material layer 121 formed on an inner surface 123a (e.g., a surface facing the winding center (C)) of the negative electrode current collector 123, and a second negative electrode active material layer 122 formed on an outer surface 123b (e.g., a surface facing the winding outer shell (O)) of the negative electrode current collector 123. The negative electrode 120 may be divided into a negative electrode coated portion (or coated portion) 125 and a negative electrode uncoated portion (or uncoated portion) depending on the positions where the first negative electrode active material layer 121 and the second negative electrode active material layer 122 are formed. The negative electrode coated portion 125 may be a region where the first negative electrode active material layer 121 and the second negative electrode active material layer 122 are formed. The negative electrode uncoated portion 126 may be a region where at least one of the first negative electrode active material layer 121 and the second negative electrode active material layer 122 is not formed. At least one negative electrode tab 260 may be fused onto the negative electrode current collector 123 of the negative electrode uncoated portion 126 by a method such as welding.

[0042] The negative electrode current collector 123 may be made of, for example, a foil containing copper (Cu) and / or nickel (Ni). At least one of the first negative electrode active material layer 121 and the second negative electrode active material layer 122 may be made of artificial graphite, lithium metal, a lithium alloy, carbon, petroleum coke, activated carbon, graphite, a silicon compound, a tin compound, a titanium compound, or an alloy thereof. At least one of the first negative electrode active material layer 121 and the second negative electrode active material layer 122 may contain, for example, non-graphite-based silica (SiO) or silicon carbide (SiC).

[0043] Since the negative electrode 120 is formed to surround the positive electrode 110 during winding, the negative electrode 120 may be formed longer than the positive electrode 110. In the winding outer shell portion (O) of the electrode assembly 100, the first negative electrode active material layer 121 formed on the inner surface 123a of the negative electrode current collector 123 may face the positive electrode 110, whereas the second negative electrode active material layer 122 formed on the outer surface 123b of the negative electrode current collector 123 may not face the positive electrode 110. As a result, in the winding outer shell portion (O) of the electrode assembly, the first negative electrode active material layer 121 may be formed longer than the second negative electrode active material layer 122. In the winding outer shell portion (O) of the electrode assembly, the end portion (e.g., the terminal end portion) of the first negative electrode active material layer 121 may be disposed closer to the end portion (e.g., the terminal end portion) of the negative electrode current collector 123 than the end portion (e.g., the terminal end portion) of the second negative electrode active material layer 122.

[0044] The separator 160 is disposed between the positive electrode 110 and the negative electrode 120 to separate and electrically insulate the positive electrode 110 and 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 on the outside of one of the positive electrode 110 and the negative electrode 120. The second separator 150 may be stacked on the outside of the other of the positive electrode 110 and the negative electrode 120. For example, when the first separator 140 is stacked on the outside of the positive electrode 110, the first separator 140 may be disposed between the second positive electrode active material layer 112 and the first negative electrode active material layer 121. When the second separator 150 is stacked on the outside of the negative electrode 120, the second separator 150 may be disposed between the first positive electrode active material layer 111 and the second negative electrode active material layer 122. Meanwhile, when a laminate in which the positive electrode 110, the first separator 140, the negative electrode 120, and the second separator 150 are sequentially stacked is wound up, a jelly roll-type electrode assembly 100 in which the second separator 150 is formed on the outermost surface can be formed.

[0045] At least one of the first separator 140 and 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.

[0046] The electrode assembly 100 according to the present invention may include a plurality of negative electrode conductive members 200 disposed in at least a portion of an area where cracks may occur in the negative electrode 120. 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.

[0047] 3a to 3d are diagrams showing various examples of negative electrode conductive members and negative electrode tabs attached to the negative electrode shown in FIG.

[0048] 3a to 3d, the plurality of negative electrode conductive members 200 can be attached to an area where cracks and / or disconnections due to cracks may occur in the negative electrode current collector 123. Even if cracks and / or disconnections due to cracks occur in the negative electrode current collector 123, a conductive path (I1, I2) is formed between the negative electrode coating portion 125 and the negative electrode tab 260 via the plurality of negative electrode conductive members 200, so that an electrical signal (e.g., current) can be supplied.

[0049] The first negative electrode conductive member 211 may be attached to the negative electrode 120 so as to overlap an end portion of the first negative electrode active material layer 121 at the end of winding. The first negative electrode conductive member 211 may be formed to cover a step due to the thickness of the first negative electrode active material layer 121 disposed on the inner surface 123a of the negative electrode current collector 123. When a break occurs in the negative electrode current collector 123 due to a crack, the first negative electrode conductive member 211 may form a first conductive path (I1) that bypasses the break in the negative electrode current collector 123. The first negative electrode conductive member 211 may form the first conductive path (I1) with the negative electrode current collector 123. The first negative electrode conductive member 211 shown in Figures 3a and 3c is in contact with the negative electrode current collector 123 and the first negative electrode active material layer 121, and can form a first conductive path (I1) between the negative electrode current collector 123 and the first negative electrode active material layer 121. The first negative electrode conductive member 211 shown in Figure 3b is in contact with the negative electrode tab 260 and the first negative electrode current collector 123, and can form a first conductive path (I1) between the negative electrode tab 260 and the first negative electrode current collector 123. The first negative electrode conductive member 211 shown in Figure 3d is in contact with one end and the other end of the negative electrode current collector 123, and can form a first conductive path (I1) between the one end and the other end of the negative electrode current collector 123.

[0050] Through this first negative electrode conductive member 211, even if a break occurs due to a crack in the negative electrode current collector 123 that contacts the end portion of the first negative electrode active material layer 121, the electrical connection within the negative electrode 120 can be maintained.

[0051] The second negative electrode conductive member 212 may be attached to the negative electrode 120 so as to overlap an end portion of the second negative electrode active material layer 122 at the end of winding. The second negative electrode conductive member 212 may be formed to cover a step due to the thickness of the second negative electrode active material layer 122 disposed on the outer surface 123b of the negative electrode current collector 123. When a break occurs in the negative electrode current collector 123 due to a crack, the second negative electrode conductive member 212 may form a second conductive path (I2) that bypasses the break in the negative electrode current collector 123. The second negative electrode conductive member 212 may be in contact with the negative electrode current collector 123 and the second negative electrode active material layer 122, thereby forming a second conductive path between the second negative electrode active material layer 122 and the negative electrode current collector 123. The second conductive path (I2) may be electrically connected to the first conductive path (I1). Even if a break occurs due to a crack in the negative electrode current collector 123 in contact with the end of the second negative electrode active material layer 122, electrical connection within the negative electrode 120 can be maintained via the second negative electrode conductive member 212.

[0052] The third negative electrode conductive member 213 may be attached to the negative electrode 120 so as to overlap the end portion of the positive electrode 110 where winding of the positive electrode 110 ends. If a break occurs due to a crack in the negative electrode current collector 123, the third negative electrode conductive member 213 may form a conductive path that bypasses the break in the negative electrode current collector 123. Even if a break occurs due to a crack in the negative electrode current collector 123 overlapping the positive electrode 110, electrical connection within the negative electrode 120 may be maintained via the third negative electrode conductive member 213.

[0053] As described above, the present invention can maintain the conductivity of the negative electrode current collector 123 through the plurality of negative electrode conductive members 211, 212, and 213, thereby preventing deterioration in battery cell performance and ensuring stability. Furthermore, the present invention can stably ensure a conductive path between the negative electrode tab 260 and the negative electrode 120 through the negative electrode conductive members 211, 212, and 213, thereby preventing charge / discharge current from concentrating at the ends of the negative electrode active material layers 211 and 212. This prevents heat generated by charge / discharge of the electrode assembly from concentrating at the ends of the negative electrode active material layers 211 and 212.

[0054] 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 in the negative electrode uncoated region 126. The negative electrode tab 260 may be attached and fixed to the negative electrode uncoated region 126 as shown in FIGS. 3a to 3d. The first negative electrode conductive member 211 shown in FIGS. 3a, 3b, and 3d may be disposed to overlap at least a portion of the negative electrode tab 260, or may be disposed spaced apart from the negative electrode tab 260 as shown in FIG. 3c.

[0055] According to one embodiment, the negative electrode tab 260 may be attached to the outer surface 123b of the negative electrode current collector 123, as shown in FIG. 3a. The first negative electrode conductive member 211 may be attached to the inner surface 123a of the negative electrode current collector 123, which is on a different plane from the negative electrode tab 260. The second negative electrode conductive member 212 and the third negative electrode conductive member 213 may be disposed on the outer surface 123b of the negative electrode current collector 123, which is on the same plane as the negative electrode tab 260. At least a portion of the negative electrode tab 260 may overlap the first negative electrode conductive member 211 across the negative electrode current collector 123. This eliminates the need for a separate space for arranging the first negative electrode conductive member 211, thereby preventing an increase in the length of the negative electrode current collector 123.

[0056] According to one embodiment, as shown in FIG. 3b, the negative electrode tab 260 may be attached to the outer surface 123b of the negative electrode current collector 123. The first negative electrode conductive member 211, the second negative electrode conductive member 212, and the third negative electrode conductive member 213 may be attached to the outer surface 123b of the negative electrode current collector 123. At least a portion of the negative electrode tab 260 may be in direct contact with and overlap the first negative electrode conductive member 211. This minimizes the space occupied by the first negative electrode conductive member 211, and therefore minimizes an increase in the length of the negative electrode current collector 123.

[0057] According to one embodiment, the negative electrode tab 260 may be attached to the inner surface 123a of the negative electrode current collector 123, as shown in FIG. 3c. The second negative electrode conductive member 212 and the third negative electrode conductive member 213 may be attached to the inner surface 123a of the negative electrode current collector 123, which is on a different plane from the negative electrode tab 260. The first negative electrode conductive member 211 may be disposed on the outer surface 123b of the negative electrode current collector 123, which is on the same plane as the negative electrode tab 260. The first negative electrode conductive member 211 may be disposed spaced apart from the negative electrode tab 260 in the winding direction.

[0058] According to one embodiment, as shown in Fig. 3d, the negative electrode tab 260 may be attached to the inner surface 123a of the negative electrode current collector 123. The first negative electrode conductive member 211, the second negative electrode conductive member 212, and the third negative electrode conductive member 213 may be attached to the outer surface 123b of the negative electrode current collector 123. At least a portion of the negative electrode tab 260, which is arranged on a different plane from the first negative electrode conductive member 211, may overlap with the first negative electrode conductive member 211 with the negative electrode current collector 123 in between.

[0059] According to one embodiment, the first negative electrode conductive member 211, the second negative electrode conductive member 212, and the third negative electrode conductive member 213 shown in Figures 3b and 3d may be arranged on the same plane. This allows the deposition process of the first negative electrode conductive member 211, the second negative electrode conductive member 212, and the third negative electrode conductive member 213 to be performed simultaneously, thereby simplifying and simplifying the deposition process.

[0060] 4a to 4c are perspective views showing various examples of the conductive member shown in FIG.

[0061] 4a to 4c, the conductive member 300 included in the electrode assembly of the present invention (e.g., the negative electrode conductive members 211, 212, and 213 in FIGS. 2 and 3a to 3d) may be formed in the form of an adhesive tape including a base layer 310 and an adhesive layer 320. As one example, the base layer 310 and the adhesive layer 320 may both have adhesive properties, and the conductive member 300 may be formed in the form of a double-sided adhesive tape. As another example, the base layer 310 may not have adhesive properties, and the adhesive layer 320 may have adhesive properties, and the conductive member 300 may be formed in the form of a single-sided adhesive tape.

[0062] When the conductive member 300 is attached to the negative electrode 120, the conductive member 300 can be disposed between the negative electrode 120 and the second separator 150. The substrate layer 310 of the conductive member 300 can face (or contact) the second separator 150. The adhesive layer 320 of the conductive member 300 can face (or contact) the negative electrode 120.

[0063] When the conductive member 300 is attached to the positive electrode 110, the conductive member 300 can be disposed between the positive electrode 110 and the first separator 140. The substrate layer 310 of the conductive member 300 can face (or contact) the first separator 140. The adhesive layer 320 of the conductive member 300 can face (or contact) the positive electrode 110.

[0064] The adhesive layer 320 may include an adhesive material and a powdered first conductive material 321 to provide both adhesiveness and conductivity. The first conductive material 321 included in the adhesive layer 320 may be formed in a pattern (e.g., a mesh) as shown in FIG. 4a, a wire as shown in FIG. 4b, or a dot as shown in FIG. 4c. The first conductive material 321 may include a metal powder of at least one of Al, Cu, Ni, Au, and Pt. The first conductive material 321 may be determined depending on 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 formed 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 formed of the same material (e.g., Al) as the positive electrode current collector 113.

[0065] 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. As a result, even if a break occurs due to a crack in the negative electrode current collector 123 that contacts the end of the first negative electrode active material layer 121, electrical connection within the negative electrode 120 can be maintained through the first conductive material 321 of the conductive member 300.

[0066] The substrate layer 310 may be formed of at least one of an insulating material and a second conductive material. The substrate layer 310 may include an insulating material such as a fabric and / or a polymer, a second conductive material such as Al, Cu, and / or a carbon-based material, or both an insulating material and a second conductive material. For example, when the conductive member 320 is applied to the step between the current collectors 113 and 123 and the active material layers 111, 112, 121, and 122, the substrate layer 310 may be formed to include 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 substrate layer 310 may be formed to include at least one of Al, Cu, and a fabric. The second conductive material included in the base layer 310 is electrically connected to the first conductive material 321, thereby improving the conductivity of the conductive member 300.

[0067] Electrode assembly according to a second embodiment 5 is a diagram showing the electrode assembly according to the second embodiment of the present invention in a state in which the positive and negative electrodes are unfolded before being wound up. The electrode assembly according to the second embodiment of the present invention has substantially the same components as the electrode assembly according to the first embodiment of the present invention shown in FIGS. 1 to 4b, except that it further includes a positive electrode conductive member. Therefore, the detailed description of the same components shall apply mutatis mutandis to the descriptions of FIGS. 1 to 4b.

[0068] Referring to FIG. 5, the electrode assembly according to the present invention may include a negative electrode 120, a positive electrode 110, a negative electrode conductive member 210 (for example, the negative electrode conductive member 210 in FIG. 2), and a positive electrode conductive member 220.

[0069] The negative electrode 120 may include a negative electrode coating portion 125 and a negative electrode uncoated portion 126. The negative electrode coating portion 125 may include a negative electrode current collector (e.g., the negative electrode current collector 123 in FIG. 2), a first negative electrode active material layer (e.g., the first negative electrode active material layer 121 in FIG. 2), and a second negative electrode active material layer (e.g., the second negative electrode active material layer 122 in FIG. 2). The negative electrode uncoated portion 126 may not include at least one of the first negative electrode active material layer and the second negative electrode active material layer. At least a portion of the negative electrode current collector disposed in 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 disposed on the winding outer shell portion (O) side. The negative electrode tab 260 may be formed adjacent to the negative electrode conductive member 210 (e.g., at least one of the negative electrode conductive members 211, 212, and 213 in FIGS. 2 and 3a to 3d). The negative electrode tab 260 may be spaced apart from the negative electrode conductive member 210 or may be arranged to overlap at least a portion of the negative electrode conductive member 210.

[0070] The negative electrode conductive member 210 may be formed to cover a step between at least one of the first negative electrode active material layer and the second negative electrode active material layer and the negative electrode current collector disposed in the negative electrode uncoated portion 126.

[0071] The positive electrode 110 may include a positive electrode coating portion 115 and a positive electrode uncoated portion 116. The positive electrode coating portion 115 may include a positive electrode current collector (e.g., the positive electrode current collector 113 in FIG. 2), a first positive electrode active material layer (e.g., the first positive electrode active material layer 111 in FIG. 2), and a second positive electrode active material layer (e.g., the second positive electrode active material layer 112 in FIG. 2). The 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 disposed in the positive electrode uncoated portion 116 may directly face the separator. At least one positive electrode tab 250 may be fused onto the positive electrode uncoated portion 116 by a method such as welding. The positive electrode tab 250 attached to the positive electrode uncoated portion 116 may be disposed on the winding center (C) side. The positive electrode tab 250 may be formed adjacent to the positive electrode conductive member 220. The positive electrode tab 250 may be disposed spaced apart from the positive electrode conductive member 220 or may be disposed so as to overlap at least a portion of the positive electrode conductive member 220.

[0072] The positive electrode conductive member 220 may be formed to cover a step between at least one of the first and second positive electrode active material layers and the positive electrode current collector disposed in the positive electrode uncoated portion 116. When a 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 disconnection. As a result, even if a disconnection occurs in the positive electrode 110, electrical connection within the positive electrode 110 may be maintained via the positive electrode conductive member 220.

[0073] 6a to 6c are plan views showing the electrode assembly according to the present invention in a state in which the negative electrode and the positive electrode, each having at least one electrode tab attached thereto, are unfolded before being wound up.

[0074] 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 portion 621, 622, 623 (e.g., the negative electrode uncoated portion 126 in FIGS. 2, 3a to 3d, and 5), and the other end may protrude beyond the negative electrode uncoated portion 621, 622, 623. The negative electrode tab 260 may be disposed adjacent to the negative electrode conductive member 210 (e.g., at least one of the negative electrode conductive members 211, 212, 213 in FIGS. 2 and 3a to 3d) disposed in the negative electrode uncoated portion 621, 622, 623.

[0075] 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 a positive electrode uncoated portion 640, 641, 642 (e.g., the positive electrode uncoated portion 116 in FIGS. 2, 3a to 3d, and 5), and one end may protrude beyond the positive electrode uncoated portion 640, 641, 642. The positive electrode tab 250 may be disposed adjacent to the positive electrode conductive member 220 disposed on the positive electrode uncoated portion 640, 641, 642.

[0076] According to one embodiment, the electrode tabs 250, 260 attached to at least one of the positive electrode 110 and the negative electrode 120 may be disposed in the winding intermediate portion between the winding center portion (C) and the winding outer shell portion (O).

[0077] For example, as shown in FIG. 6a, multiple negative electrode tabs 260 may be attached to the negative electrode 120. The negative electrode 120 may include a negative electrode coating portion 610, a first negative electrode uncoated portion 621 located toward the winding center (C) relative to the negative electrode coating portion 610, and a second negative electrode uncoated portion 622 located toward the winding outer shell (O) relative to the negative electrode coating portion 610. Negative electrode tabs 260 may be attached to the first negative electrode uncoated portion 621 and the second negative electrode uncoated portion 622, respectively. This forms a signal transmission path between the negative electrode tab 260 attached to the first negative electrode uncoated portion 621 and the negative electrode coating portion 610, and between the negative electrode tab 260 attached to the second negative electrode uncoated portion 622 and the negative electrode coating portion 610, allowing current to be supplied in both 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 coating portion 631 located on the winding center (C) side of the positive electrode uncoated portion 640, and a second positive electrode uncoated portion 632 located on the winding outer shell (O) side of the positive electrode uncoated portion 640. The positive electrode uncoated portion 640 may be disposed in the winding middle portion between the winding center (C) and the winding outer shell (O). Signal transmission paths are formed between the positive electrode tab 250 attached on the positive electrode uncoated portion 640 and the first positive electrode coating portion 631, and between the positive electrode tab 250 attached on the positive electrode uncoated portion 640 and the second positive electrode coating portion 632, allowing current to be supplied in both directions. At least one conductive member 210, 220 may be attached to each of the positive electrode 110 and the negative electrode 120. A positive electrode conductive member 220 may be attached to the positive electrode 110 to cover a step between the positive electrode active material layer included in at least one of the first positive electrode coating portion 631 and the second positive electrode coating portion 632 and the positive electrode current collector of the positive electrode uncoated portion 640. As a result, even if a crack and / or a disconnection due to a crack occurs in the positive electrode current collector included in the positive electrode uncoated portion 640, an electrical connection between the positive electrode coating portions 631 and 632 and the positive electrode tab 250 can be maintained via the positive electrode conductive member 220. A negative electrode conductive member 210 may be attached to the negative electrode 120 to cover a step between the negative electrode coating portion 610 and each of the first negative electrode uncoated portion 631 and the second negative electrode uncoated portion 621.As a result, even if cracks and / or disconnections due to cracks occur in the negative electrode current collectors included in the first negative electrode uncoated portion 621 and the second negative electrode uncoated portion 622, the electrical connection between the negative electrode coating portion 610 and the negative electrode tab 260 can be maintained via the negative electrode conductive member 210.

[0078] As another example, as shown in FIG. 6b, a plurality of positive electrode tabs 250 may be attached to the positive electrode 110. The positive electrode 110 may include first to third positive electrode coating portions 631, 632, and 633, and first and second positive electrode uncoated portions 641 and 642. The first positive electrode coating portion 631 may be disposed toward the center of the winding relative to the third positive electrode coating portion 633. The second positive electrode coating portion 632 may be disposed toward the outer periphery of the winding relative to the third positive electrode coating portion 633. The first positive electrode uncoated portion 641 may be disposed between the first positive electrode coating portion 631 and the third positive electrode coating portion. The second positive electrode uncoated portion 642 may be disposed between the second positive electrode coating portion 632 and the third positive electrode coating portion 633. A signal transmission path can be formed in both directions between the first positive electrode coating portion 631 and the third positive electrode coating portion 633, respectively, and the positive electrode tab 250 attached on the first positive electrode uncoated portion 641, allowing current to be supplied in both directions. A signal transmission path can be formed in both directions between the second positive electrode coating portion 632 and the third positive electrode coating portion 633, respectively, and the positive electrode tab 250 attached on the second positive electrode uncoated portion 642, allowing current to be supplied in both directions. A positive electrode conductive member 220 can 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 a step between the first positive electrode coating portion 631 and the first positive electrode uncoated portion 641, a step between the first positive electrode uncoated portion 641 and the second positive electrode coating portion 632, a step between the second positive electrode coating portion 632 and the second positive electrode uncoated portion 642, and a step between the second positive electrode uncoated portion 642 and the third positive electrode coating portion 633. As a result, even if cracks and / or disconnections due to cracks occur in the positive electrode current collector, electrical connection between the positive electrode coating portions 631, 632, and 633 and the positive electrode tab 250 can be maintained via the positive electrode conductive member 220.

[0079] Meanwhile, the negative electrode 120, the negative electrode tab 260, and the negative electrode conductive member 210 shown in FIG. 6b are substantially similar to the negative electrode 120, the negative electrode tab 260, and the negative electrode conductive member 210 shown in FIG. 6a, respectively, and therefore the description of FIG. 6a applies mutatis mutandis.

[0080] As another example, as shown in FIG. 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 regions 621, 622, and 623, and first and second negative electrode coating regions 611 and 612. The first negative electrode uncoated region 621 may be disposed on the winding center (C) side relative to the third negative electrode uncoated region 623. The second negative electrode uncoated region 622 may be disposed on the winding outer shell (O) side relative to the third negative electrode uncoated region 623. The first negative electrode coating region 611 may be disposed between the first negative electrode uncoated region 621 and the third negative electrode uncoated region 623. The second negative electrode coating region 612 may be disposed between the second negative electrode uncoated region 622 and the third negative electrode uncoated region 623. A bidirectional signal transmission path can be formed between the negative electrode tabs 260 attached on the first negative electrode uncoated portion 621 and the negative electrode tabs 260 attached on the third negative electrode uncoated portion 623 and the first negative electrode coating portion 611. A bidirectional signal transmission path can be formed between the negative electrode tabs 260 attached on the second negative electrode uncoated portion 622 and the negative electrode tabs 260 attached on the third negative electrode uncoated portion 623 and the second negative electrode coating portion 612, and the current can be supplied in both directions.

[0081] The negative electrode conductive member 210 may be attached to an area of ​​the negative electrode 120 where disconnection may occur. The negative electrode conductive member 210 may be attached to cover a step between the first negative electrode coating portion 611 and the first negative electrode uncoated portion 621, a step between the first negative electrode coating portion 611 and the third negative electrode uncoated portion 623, a step between the third negative electrode uncoated portion 623 and the second negative electrode coating portion 621, and a step between the second negative electrode coating portion 621 and the second negative electrode uncoated portion 622. As a result, even if cracks and / or disconnections due to 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 via the negative electrode conductive member 210.

[0082] Meanwhile, the positive electrode 110, the positive electrode tab 250, and the positive electrode conductive member 220 shown in FIG. 6c are substantially similar to the positive electrode 110, the positive electrode tab 250, and the positive electrode conductive member 220 shown in FIG. 6b, respectively, and therefore the description of FIG. 6b applies mutatis mutandis.

[0083] FIG. 7 is an exploded perspective view for explaining in detail the non-coating portion arranged in the winding intermediate portion shown in FIGS. 6a to 6c.

[0084] 7, at least one electrode 720 of the positive and negative electrodes may include a current collector 723 (e.g., the negative current collector 123 or the positive current collector 113 in FIG. 2), a first active material layer 721 (e.g., the first negative active material layer 121 or the first positive active material layer 111 in FIG. 2) formed on an inner surface of the current collector 723, and a second active material layer 722 (e.g., the second negative active material layer 122 or the second positive active material layer 112 in FIG. 2) formed on an outer surface of the current collector 723. In a winding intermediate portion between the outer winding portion (O) and the central winding portion (C), the electrode 720 may include a plain portion 730, a first coating portion 741 disposed on one side of the plain portion 730, and a second coating portion 742 disposed on the other side of the plain portion 730.

[0085] The number of conductive members 710 may be determined depending on the positions of the ends of the first active material layer 721 and the second active material layer 722. As an example, the ends of the first active material layer 721 and the second active material layer 722 may be arranged on different imaginary vertical lines. In this case, cracks due to a step between the first active material layer 721 and the current collector 723 and cracks due to a step between the second active material layer 722 and the current collector 723 may occur at different positions. Therefore, at least two conductive members 710 may be provided to prevent disconnection due to cracks occurring at different positions. As another example, the ends of the first active material layer 721 and the second active material layer 722 may be arranged on the same imaginary vertical line. In this case, cracks due to a step between the first active material layer 721 and the current collector 723 and cracks due to a step between the second active material layer 722 and the current collector 723 may occur at the same position. Therefore, at least one conductive member 710 can be provided to prevent disconnection due to cracks occurring at the same position.

[0086] The conductive member 710 located in the intermediate winding section 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.

[0087] Two steps located on different imaginary vertical lines are formed between the first coating portion 741 and the uncoated portion 730, and therefore a first conductive member 701 and a second conductive member 702 may be disposed between the first coating portion 741 and the uncoated portion 730. The first conductive member 701 may be formed to cover the step between the first active material layer 721 and the current collector 723 included in the first coating portion 741. The second conductive member 702 may be formed to cover the step between the second active material layer 722 and the current collector 723 included in the first coating portion 741.

[0088] Two steps located on the same imaginary vertical line are formed between the second coating portion 742 and the uncoated portion 730, and therefore a third conductive member 703 may be disposed between the second coating portion 742 and the uncoated portion 730. The third conductive member 703 may be formed to cover the step between the current collector 723 and one of the first active material layer 721 and the second active material layer 722 included in the second coating portion 742.

[0089] As described above, even if a break occurs due to a crack in the current collector 723 that forms a step with the active material layers 721 and 722, the electrical connection within the electrode 720 can be maintained via the conductive member 710. As a result, the present invention can maintain the conductivity of the electrode 720 via the conductive member 710, thereby preventing performance degradation and ensuring stability of the battery cell.

[0090] The electrode assembly described above is not limited to the embodiments shown in the drawings, and the structures shown in the drawings may be combined. A secondary battery including an electrode assembly according to the present invention may employ a plurality of negative electrodes, each of which is shown in FIGS. 3a to 3d, or a combination of negative electrodes, each of which is shown in FIGS. 3a to 3d. An electrode assembly according to the present invention may employ a plurality of conductive members, each of which is shown in FIGS. 4a to 4c, or a combination of conductive members, each of which is shown in FIGS. 4a to 4c. The conductive member, including the base material layer and adhesive conductive layer shown in FIGS. 4a to 4c, according to the present invention may be disposed in at least one of the central winding portion, the outer winding portion, and the intermediate winding portion. An electrode assembly according to the present invention may employ a positive electrode and a negative electrode, each of which is shown in FIGS. 6a to 6c, or a combination of positive electrodes and negative electrodes, each of which is shown in FIGS. 6a to 6c. An intermediate winding portion, as shown in FIG. 7, may be applied to each embodiment of the electrode assembly according to the present invention. Although the electrode assembly according to the present invention has been described using a structure applied to a cylindrical secondary battery as an example, the present invention is not limited thereto, and the conductive member according to the present invention may also be applied to a pouch-type or prismatic battery.

[0091] The secondary battery including the electrode assembly described above can be applied to various devices, including, but not limited to, transportation means such as electric bicycles, electric cars, and hybrid vehicles, and can be applied to various devices that can use a battery module.

[0092] Although the present invention has been described above using limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the scope equivalent to the technical concept of the present invention and the claims that will be described later by a person having ordinary skill in the art to which the present invention pertains. [Explanation of symbols]

[0093] 100: Electrode assembly 110: Positive electrode 120: Negative electrode 140: First separator 150: Second separator 250, 260: Electrode tab 210, 220, 701, 702, 703: Conductive members

Claims

1. a positive electrode and a negative electrode; a separator disposed between the positive electrode and the negative electrode; a plurality of conductive members disposed between the separator and at least one of the positive electrode and the negative electrode; Including, At least one of the positive electrode and the negative electrode is A 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; Including, The conductive member is a first conductive member formed to overlap an end of the first active material layer and forming a first conductive path together with the current collector; a second conductive member formed so as to overlap an end of the second active material layer and forming a second conductive path between the current collector and the second active material layer; An electrode assembly comprising:

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

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

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

5. The conductive member is a substrate layer disposed between the separator and the electrode; 2. The electrode assembly of claim 1, further comprising: an adhesive conductive layer disposed on the substrate layer, the adhesive conductive layer comprising a first conductive material, and the adhesive conductive layer adhering to the electrode.

6. The first conductive material is The electrode assembly according to claim 5 , wherein the electrodes are formed from the same material as the current collector and are arranged in a dot, line, or pattern.

7. The electrode assembly of claim 5 , wherein the first conductive material includes a metal powder of at least one of Al, Cu, Ni, Au, and Pt.

8. The electrode assembly of claim 5 , wherein the base layer includes at least one of a second conductive material and an insulating material.

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

10. at least one of the first conductive member and the second conductive member is attached to the current collector excluding the first active material layer and the second active material layer; The electrode assembly of claim 8 , wherein the substrate layer includes at least one of Al, Cu, and fabric.

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

12. The electrode is a coating portion including the current collector, the first active material layer, and the second active material layer; a non-coated 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; The electrode assembly of claim 1 , wherein an electrode tab is attached to the uncoated portion of the electrode.

13. At least one of the first conductive member and the second conductive member is The electrode assembly according to claim 12 , wherein the electrode tab is formed 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 at a position corresponding to a winding end of the positive electrode.

15. The electrode assembly of claim 14 , wherein the third conductive member is disposed flush with at least a portion of the first conductive member.

16. The first conductive member is formed so as to cover the winding end portion of the first active material layer included in the negative electrode, The second conductive member is The electrode assembly of claim 1 , wherein the electrode assembly is formed to cover a winding end portion of the second active material layer included in the negative electrode.

17. A secondary battery comprising the electrode assembly according to any one of claims 1 to 16.

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