Electrode assembly and secondary battery containing 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 the contents disclosed in the document of the 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 Art

[0003] In recent years, the demand for portable electronic products such as notebook computers, video cameras, and mobile phones has increased rapidly. As the development of electric vehicles, energy storage batteries, robots, satellites, etc. has become full-scale, many studies have been conducted on secondary batteries used as their driving power sources.

[0004] Secondary 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 rechargeable power generation element having a structure in which electrodes and separators are laminated.

[0005] When the charge / discharge cycle of a secondary battery including such an electrode assembly is repeated, stress caused by the expansion and contraction of the electrodes can accumulate inside the electrode assembly. If the accumulation of stress exceeds a certain limit, deformation of the electrode assembly may occur, resulting in a decrease in battery stability and performance defects.

Summary of the Invention

Problems to be Solved by the Invention

[0006] An embodiment of the present invention aims 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 can be clearly understood by an ordinary person 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 the inner surface of the current collector, and a second active material layer disposed on the outer surface of the current collector, and the conductive member may include a first conductive member formed to overlap with the end 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 with the end of the second active material layer and to form a second conductive path between the current collector and the second active material layer.

[0009] According to one embodiment, the end of the first active material layer can be positioned closer to the end of the current collector than the end of the second active material layer.

[0010] According to one embodiment, the first conductive member is disposed on the inner surface of the current collector and forms a 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 and forms a second conductive path that is electrically connected to the first conductive path.

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

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

[0013] According to one embodiment, the first conductive material is formed from the same material as the current collector and can be arranged in a dot, linear, or patterned manner.

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

[0015] According to one embodiment, the substrate 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 either 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 base layer may include at least one of Al, Cu, and fabric.

[0018] According to one embodiment, the first conductive material can 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 but not including at least one of the first active material layer and the second active material layer, and an electrode tab can 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 can be formed across at least one of both sides of the electrode tab and the current collector.

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

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

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

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

Advantages of the Invention

[0025] According to an embodiment of the present invention, it can include a plurality of conductive members disposed in at least a part of the region where cracks may occur in the electrode. Thereby, even if a disconnection due to cracks occurs in the electrode, the electrical connection within the electrode can be maintained through the conductive members, so that it is possible to improve the performance degradation of the cell and ensure stability.

[0026] In addition to this, various effects directly or indirectly grasped by this document can be provided.

Brief Description of the Drawings

[0027] [Figure 1] It is a perspective view showing a secondary battery including an electrode assembly according to a first embodiment of the present invention. [Figure 2] It is an exploded perspective view showing the developed state before the electrode assembly shown in FIG. 1 is wound up. [Figure 3a] It is a cross-sectional view showing various examples of the negative electrode conductive member and the negative electrode tab attached to the negative electrode shown in FIG. 2. [Figure 3b] It is a cross-sectional view showing various examples of the negative electrode conductive member and the negative electrode tab attached to the negative electrode shown in FIG. 2. [Figure 3c] It is a cross-sectional view showing various examples of the negative electrode conductive member and the negative electrode tab attached to the negative electrode shown in FIG. 2. [Figure 3d] It is a cross-sectional view showing various examples of the negative electrode conductive member and the negative electrode tab attached to the negative electrode shown in FIG. 2. [Figure 4a] It is a perspective view showing various examples of the conductive member shown in FIG. 2. [Figure 4b] It is a perspective view showing various examples of the conductive member shown in FIG. 2. [Figure 4c] It is a perspective view showing various examples of the conductive member shown in FIG. 2. [Figure 5] It is an exploded view showing the developed state of the positive electrode and the negative electrode before the electrode assembly according to the second embodiment of the present invention is wound up. [Figure 6a] It is a plan view showing the developed state of the negative electrode and the positive electrode to which at least one electrode tab is respectively attached before the electrode assembly according to the present invention is wound up. [Figure 6b] It is a plan view showing the developed state of the negative electrode and the positive electrode to which at least one electrode tab is respectively attached before the electrode assembly according to the present invention is wound up. [Figure 6c] It is a plan view showing the developed state of the negative electrode and the positive electrode to which at least one electrode tab is respectively attached before the electrode assembly according to the present invention is wound up. [Figure 7] It is an exploded view for explaining in detail the plain portion disposed in the winding intermediate portion shown in FIGS. 6a to 6c.

Mode for Carrying Out the Invention

[0028] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. However, the present invention may be realized in various different forms and is not limited or restricted by the following embodiments.

[0029] To clearly explain the present invention, detailed descriptions of relevant prior art that are irrelevant to the description or that may unnecessarily obscure the essence of the invention have been omitted. In this specification, when assigning reference numerals to components in each drawing, the same or similar reference numerals are assigned to components that are the same or similar throughout the specification.

[0030] Furthermore, the terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather should be interpreted in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors may appropriately define the concepts of terms in order to best describe their invention.

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

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

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

[0034] The battery casing 182 may include a housing 183 capable of accommodating the electrode assembly 100. Electrolyte can be injected into the housing 183 so that the electrode assembly 100 is completely immersed within the battery casing 182. The top of the battery casing 182 may be open to serve as an inflow passage for the electrode assembly 100. The battery casing 182 may be made of metal. For example, the battery casing 182 may be made of stainless steel.

[0035] The battery can 182 can be formed in a shape corresponding to the shape of the electrode assembly 100 in order to house the electrode assembly 100. For example, the battery can 182 can be formed in a cylindrical shape so as to house the electrode assembly 100 which is formed in the shape of a jelly roll.

[0036] The cap assembly 181 is mounted on the battery can 182 so as to cover the open top of the battery can 182 and can be coupled to the battery can 182. The cap assembly 181 can be made up of a safety vent, a current interruption element, a PTC (Positive Temperature Coefficient) element, and a top cap, which are sequentially stacked. The top cap is placed on top of the cap assembly 181 and coupled to it, and transmits the current generated from the secondary battery to the outside.

[0037] Either the battery canister 182 or the cap assembly 181 can be electrically connected to the positive electrode tab 250 of the electrode assembly 100, and the other battery canister 182 or the other cap assembly 181 can be electrically connected to the negative electrode tab 260. For example, the cap assembly 181 can be electrically connected to the positive electrode tab 250 by a welding process, and the bottom of the battery canister 182 can be electrically connected to the negative electrode tab 260 by a welding process. In other examples, either the battery canister 182 or the cap assembly 181 can be electrically connected to both the positive electrode tab 250 and the negative electrode tab 260.

[0038] The electrode assembly 100 may be a power generation element capable of charging and discharging. The electrode assembly 100 forms a structure in which electrodes 130 and separators 160 are assembled and stacked alternately. The electrode assembly 100 can be formed in a form in which electrodes 130 and separators 160 are assembled alternately and wound up. The electrode assembly 100 may have a structure in which the diameter expands radially in proportion to the winding rotation speed. In this case, the electrode assembly 100 can be wound up in a cylindrical shape around a winding center (or central axis) (C). As an 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 a positive electrode 110, a first separator 140, a negative electrode 120, and a 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 the inner surface of the positive electrode current collector 113 (for example, the surface facing the winding center (C)), and a second positive electrode active material layer 112 formed on the outer surface of the positive electrode current collector 113 (for example, the surface facing the winding outer casing (O)) 123b. The positive electrode 110 does not need to have a blank positive electrode portion formed on the winding outer casing (O). In the winding outer casing (O), the positive electrode current collector 113 does not need to protrude beyond the first positive electrode active material layer 111 and the second positive electrode active material layer 111.

[0040] For example, the positive electrode current collector 113 may consist 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 consist of, for example, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or compounds and mixtures 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 the inner surface (e.g., the surface facing the winding center (C)) 123a of the negative electrode current collector 123, and a second negative electrode active material layer 122 formed on the outer surface (e.g., the surface facing the winding outer casing (O)) 123b of the negative electrode current collector 123. Depending on the formation locations of the first negative electrode active material layer 121 and the second negative electrode active material layer 122, the negative electrode 120 can be divided into a negative electrode coated portion (or surfaced portion) 125 and a negative electrode plain portion (or uncoated portion). The negative electrode coated portion 125 may be the region where the first negative electrode active material layer 121 and the second negative electrode active material layer 122 are formed. The negative electrode plain portion 126 may be the 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 can be fused onto the negative electrode current collector 123 of the negative electrode blank portion 126 by a method such as welding.

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

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

[0044] The separator 160 is placed between the positive electrode 110 and the negative electrode 120, and can 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 can be stacked on the outside of either the positive electrode 110 or the negative electrode 120. The second separator 150 can be stacked on the outside of the other one of the positive electrode 110 and the negative electrode 120. For example, if the first separator 140 is stacked on the outside of the positive electrode 110, the first separator 140 can be placed between the second positive electrode active material layer 112 and the first negative electrode active material layer 121. If the second separator 150 is stacked on the outside of the negative electrode 120, the second separator 150 can be placed between the first positive electrode active material layer 111 and the second negative electrode active material layer 122. On the other hand, 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 can be formed in which the second separator 150 is formed on the outermost surface.

[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 solid polymer electrolytes or gel-type polymer electrolytes 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 that are disposed in at least a portion 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.

[0047] Figures 3a to 3d show various examples of negative electrode conductive members and negative electrode tabs that adhere to the negative electrode shown in Figure 2.

[0048] Referring to Figures 3a to 3d, the multiple negative electrode conductive members 200 can be attached to areas of the negative electrode current collector 123 where cracks and / or disconnections due to cracks may occur. 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 multiple negative electrode conductive members 200, allowing for the supply of electrical signals (e.g., current).

[0049] The first negative electrode conductive member 211 can be attached to the negative electrode 120 so as to overlap with the end portion of the first negative electrode active material layer 121 where winding is completed. The first negative electrode conductive member 211 can be formed to cover the step caused by the thickness of the first negative electrode active material layer 121 which is placed on the inner surface 123a of the negative electrode current collector 123. The first negative electrode conductive member 211 can form a first conductive path (I1) that bypasses the broken portion of the negative electrode current collector 123 when a crack occurs in the negative electrode current collector 123. The first negative electrode conductive member 211 can form a first conductive path (I1) with the negative electrode current collector 123. The first negative electrode conductive member 211 shown in Figures 3a and 3c contacts 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 contacts the negative electrode tab 260 and the first negative electrode current collector 123, and can form a first conductive path (I1) between the 260 and 123. The first negative electrode conductive member 211 shown in Figure 3d contacts one end and the other end of the negative electrode current collector 123, and can form a first conductive path (I1) between one end and the other end of the negative electrode current collector 123.

[0050] Even if a crack occurs in the negative electrode current collector 123 that is in contact with the terminal end of the first negative electrode active material layer 121, the electrical connection within the negative electrode 120 can be maintained via such a first negative electrode conductive member 211.

[0051] The second negative electrode conductive member 212 can be attached to the negative electrode 120 so as to overlap with the end portion of the second negative electrode active material layer 122 where winding is completed. The second negative electrode conductive member 212 can be formed to cover the step caused by the thickness of the second negative electrode active material layer 122 which is placed on the outer surface 123b of the negative electrode current collector 123. If a break in the negative electrode current collector 123 occurs due to a crack, the second negative electrode conductive member 212 can form a second conductive path (I2) that bypasses the break in the negative electrode current collector 123. The second negative electrode conductive member 212 can contact the negative electrode current collector 123 and the second negative electrode active material layer 122, and can form 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) can be electrically connected to the first conductive path (I1). Even if a crack occurs in the negative electrode current collector 123 that is in contact with the end of the second negative electrode active material layer 122, the 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 can be attached to the negative electrode 120 so as to overlap with the end portion of the positive electrode 110 where winding of the positive electrode 110 is completed. The third negative electrode conductive member 213 can form a conductive path that bypasses the broken portion of the negative electrode current collector 123 if a crack causes a break in the negative electrode current collector 123. Even if a crack causes a break in the negative electrode current collector 123 that overlaps with the positive electrode 110, the electrical connection within the negative electrode 120 can be maintained via the third negative electrode conductive member 213.

[0053] Thus, the present invention can maintain the conductivity of the negative electrode current collector 123 via multiple negative electrode conductive members 211, 212, and 213, thereby preventing performance degradation and ensuring stability of the battery cell. Furthermore, the present invention can stably secure a conductive path between the negative electrode tab 260 and the negative electrode 120 via the negative electrode conductive members 211, 212, and 213, thereby preventing the concentration of charge and discharge current at the ends of the negative electrode active material layers 211 and 212. This prevents the heat generated by the charging and discharging 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 can be positioned adjacent to at least one of the multiple negative electrode conductive members 211, 212, and 213 arranged on the negative electrode blank portion 126. The negative electrode tab 260 can be attached to and fixed to the negative electrode blank portion 126 as shown in Figures 3a to 3d. The first negative electrode conductive member 211 shown in Figures 3a, 3b, and 3d can be positioned so as to overlap at least a portion of the negative electrode tab 260, or it can be positioned away from the negative electrode tab 260 as shown in Figure 3c.

[0055] According to one embodiment, the negative electrode tab 260 can be attached to the outer surface 123b of the negative electrode current collector 123, as shown in Figure 3a. The first negative electrode conductive member 211 can 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 can be arranged 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 can overlap with the first negative electrode conductive member 211, with the negative electrode current collector 123 in between. This eliminates the need to provide a separate space for the first negative electrode conductive member 211, thus preventing an increase in the length of the negative electrode current collector 123.

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

[0057] According to one embodiment, the negative electrode tab 260 can be attached to the inner surface 123a of the negative electrode current collector 123, as shown in Figure 3c. The second negative electrode conductive member 212 and the third negative electrode conductive member 213 can 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 can be placed 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 can be placed at a distance from the negative electrode tab 260 in the winding direction.

[0058] According to one embodiment, the negative electrode tab 260 can be attached to the inner surface 123a of the negative electrode current collector 123, as shown in Figure 3d. The first negative electrode conductive member 211, the second negative electrode conductive member 212, and the third negative electrode conductive member 213 can 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 positioned on a plane different from that of the first negative electrode conductive member 211, can overlap with the first negative electrode conductive member 211 across the negative electrode current collector 123.

[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 can be arranged on the same plane. This allows the adhesion 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 carried out simultaneously, thus simplifying the adhesion process.

[0060] Figures 4a to 4c are perspective views showing various examples of the conductive material shown in Figure 2.

[0061] Referring to Figures 4a to 4c, the conductive members 300 included in the electrode assembly of the present invention (for example, the negative electrode conductive members 211, 212, and 213 in Figures 2 and 3a to 3d) can be formed in the form of an adhesive tape including a base layer 310 and an adhesive layer 320. For example, both the base layer 310 and the adhesive layer 320 have adhesive properties, and the conductive members 300 can be formed in the form of a double-sided adhesive tape. As another example, the base layer 310 does not have adhesive properties, the adhesive layer 320 does, and the conductive members 300 can 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 positioned between the negative electrode 120 and the second separator 150. The base layer 310 of the conductive member 300 can face (or be in contact with) the second separator 150. The adhesive layer 320 of the conductive member 300 can face (or be in contact with) the negative electrode 120.

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

[0064] The adhesive layer 320 may contain an adhesive substance and a powdered first conductive substance 321 so as to be both adhesive and conductive. The first conductive substance 321 contained in the adhesive layer 320 may be formed in a pattern (e.g., a mesh) as shown in Figure 4a, in a wire shape as shown in Figure 4b, or in a dot shape as shown in Figure 4c. The first conductive substance 321 may contain at least one metal powder from Al, Cu, Ni, Au, and Pt. The first conductive substance 321 can be determined according to the material of the electrode 130 to which the conductive member 300 is attached. For example, if the conductive member 300 is attached to the negative electrode 120, the first conductive substance 321 may be formed from the same material (e.g., Cu) as the negative electrode current collector 123. If the conductive member 300 is attached to the positive electrode 110, the first conductive substance 321 may be formed from the same material (e.g., Al) as the positive electrode current collector 113.

[0065] The first conductive material 321 of the conductive member 300 can 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 can 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 crack occurs in the negative electrode current collector 123 that is in contact with the end of the first negative electrode active material layer 121, the electrical connection within the negative electrode 120 can be maintained via the first conductive material 321 of the conductive member 300.

[0066] The base layer 310 can be formed from at least one of an insulating material and a second conductive material. The base layer 310 may contain an insulating material such as a fabric and / or a polymer, or a second conductive material such as Al, Cu, and / or a carbon-based material, or it may contain both an insulating material and a second conductive material. For example, if the conductive member 320 is applied to a step between the current collectors 113, 123 and the active material layers 111, 112, 121, 122, the base layer 310 can be formed to contain at least one of a polymer and a carbon-based material. If the conductive member 300 does not adhere to the active material layers 111, 112, 121, 122 but adheres to the current collectors 113, 123, the base layer 310 can be formed to contain at least one of Al, Cu, and a fabric. Since the second conductive material contained in the base layer 310 is electrically connected to the first conductive material 321, the conductivity of the conductive member 300 can be improved.

[0067] Electrode assembly according to the second embodiment Figure 5 shows the electrode assembly according to the second embodiment of the present invention in an unfolded state before winding. 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 Figures 1 to 4b, except that it further comprises a positive electrode conductive member. Accordingly, a detailed explanation of the same components will be provided by following the explanation in Figures 1 to 4b.

[0068] Referring to Figure 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 Figure 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 blank portion 126. The negative electrode coating portion 125 may include a negative electrode current collector (e.g., the negative electrode current collector 123 in Figure 2), a first negative electrode active material layer (e.g., the first negative electrode active material layer 121 in Figure 2), and a second negative electrode active material layer (e.g., the second negative electrode active material layer 122 in Figure 2). The negative electrode blank 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 positioned on the negative electrode blank portion 126 may face the separator directly. The negative electrode tab 260 adhering to the negative electrode blank portion 126 may be positioned on the winding outer casing (O) side. The negative electrode tab 260 can be formed adjacent to the negative electrode conductive member 210 (for example, at least one of the negative electrode conductive members 211, 212, and 213 in Figures 2 and 3a to 3d). The negative electrode tab 260 can be positioned away from the negative electrode conductive member 210, or it can be positioned so as to overlap at least a portion of the negative electrode conductive member 210.

[0070] The negative electrode conductive member 210 can be formed to cover the 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 blank portion 126.

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

[0072] The positive electrode conductive member 220 can be formed to cover the step 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 placed in the positive electrode blank portion 116. The positive electrode conductive member 220 can form a conductive path that bypasses the broken part when a break occurs between the positive electrode active material layer and the positive electrode current collector. This allows the electrical connection within the positive electrode 110 to be maintained via the positive electrode conductive member 220 even if a break occurs in the positive electrode 110.

[0073] Figures 6a to 6c are plan views showing the unfolded state of the negative electrode and positive electrode, each with at least one electrode tab attached, before the electrode assembly according to the present invention is wound up.

[0074] Referring to Figures 6a to 6c, multiple negative electrode tabs 260 can be attached to the negative electrode 120. One end of the negative electrode tab 260 is attached to and fixed to the negative electrode blank sections 621, 622, 623 (for example, the negative electrode blank section 126 in Figures 2, 3a to 3d, and 5), and the other end can protrude beyond the negative electrode blank sections 621, 622, 623. The negative electrode tab 260 can be positioned adjacent to the negative electrode conductive members 210 (for example, at least one of the negative electrode conductive members 211, 212, and 213 in Figures 2 and 3a to 3d) that are located on the negative electrode blank sections 621, 622, 623.

[0075] At least one positive electrode tab 250 can be attached to the positive electrode 110. The other end of the positive electrode tab 250 is attached to and fixed to the positive electrode blank sections 640, 641, 642 (for example, the positive electrode blank section 116 in Figures 2, 3a to 3d and 5), and one end can protrude beyond the positive electrode blank sections 640, 641, 642. The positive electrode tab 250 can be positioned adjacent to the positive electrode conductive member 220 located on the positive electrode blank sections 640, 641, 642.

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

[0077] As an example, as shown in Figure 6a, multiple negative electrode tabs 260 can be attached to the negative electrode 120. The negative electrode 120 may include a negative electrode coating portion 610, a first negative electrode blank portion 621 located on the winding center (C) side with respect to the negative electrode coating portion 610, and a second negative electrode blank portion 622 located on the winding outer casing (O) side with respect to the negative electrode coating portion 610. Negative electrode tabs 260 can be attached to the first negative electrode blank portion 621 and the second negative electrode blank portion 622, respectively. This forms a signal transmission path between the negative electrode tab 260 attached to the first negative electrode blank portion 621 and the negative electrode coating portion 610, and between the negative electrode tab 260 attached to the second negative electrode blank portion 622 and the negative electrode coating portion 610, allowing current to be supplied in both directions. One positive electrode tab 250 can be attached to the positive electrode 110. The positive electrode 110 may include a blank positive electrode portion 640, a first positive electrode coated portion 631 located on the winding center (C) side with respect to the blank positive electrode portion 640, and a second blank positive electrode portion 632 located on the winding outer casing (O) side with respect to the blank positive electrode portion 640. The blank positive electrode portion 640 can be positioned in the winding intermediate portion between the winding center (C) and the winding outer casing (O). A signal transmission path is formed between the positive electrode tab 250 attached to the blank positive electrode portion 640 and the first positive electrode coated portion 631, and between the positive electrode tab 250 attached to the blank positive electrode portion 640 and the second positive electrode coated portion 632, so that current can be supplied in both directions. At least one conductive member 210, 220 can be attached to the positive electrode 110 and the negative electrode 120, respectively. A positive electrode conductive member 220 can be attached to the positive electrode 110 so as to cover the step between the positive electrode active material layer contained 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 blank portion 640. This allows the electrical connection between the positive electrode coating portions 631, 632 and the positive electrode tab 250 to be maintained via the positive electrode conductive member 220, even if a crack or / or disconnection due to a crack occurs in the positive electrode current collector contained in the positive electrode blank portion 640. A negative electrode conductive member 210 can be attached to the negative electrode 120 so as to cover the step between the first negative electrode blank portion and the second negative electrode blank portion 621 and the negative electrode coating portion 610, respectively.As a result, even if cracks or / or disconnections due to cracks occur in the negative electrode current collectors included in the first negative electrode blank portion 621 and the second negative electrode blank portion 622, the electrical connection between the negative electrode coated 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 Figure 6b, a plurality of positive electrode tabs 250 can be attached to the positive electrode 110. The positive electrode 110 may include first to third positive electrode coated portions 631, 632, 633, and first and second positive electrode blank portions 641, 642. The first positive electrode coated portion 631 may be positioned towards the winding center with respect to the third positive electrode coated portion 633. The second positive electrode coated portion 632 may be positioned towards the winding outer edge with respect to the third positive electrode coated portion 633. The first positive electrode blank portion 641 may be positioned between the first positive electrode coated portion 631 and the third positive electrode coated portion. The second positive electrode blank portion 642 may be positioned between the second positive electrode coated portion 632 and the third positive electrode coated portion 633. Since signal transmission paths 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 to the first positive electrode blank portion 641, current can be supplied in both directions. Since signal transmission paths 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 to the second positive electrode blank portion 642, current can be supplied in both directions. A positive electrode conductive member 220 can be attached to the positive electrode 110 in areas where there is a risk of wire breakage. The positive electrode conductive member 220 can be attached in a manner that covers the steps between the first positive electrode coated portion 631 and the first positive electrode plain portion 641, the steps between the first positive electrode plain portion 641 and the second positive electrode coated portion 632, the steps between the second positive electrode coated portion 632 and the second positive electrode plain portion 642, and the steps between the second positive electrode plain portion 642 and the third positive electrode coated portion 633. This allows the electrical connection between the positive electrode coated portions 631, 632, 633 and the positive electrode tab 250 to be maintained via the positive electrode conductive member 220, even if a crack or / or disconnection occurs in the positive electrode current collector due to a crack.

[0079] On the other hand, the negative electrode 120, negative electrode tab 260, and negative electrode conductive member 210 shown in Figure 6b are substantially the same as the negative electrode 120, negative electrode tab 260, and negative electrode conductive member 210 shown in Figure 6a, so the explanation of Figure 6a will apply mutatis mutandis.

[0080] As another example, as shown in Figure 6c, at least three negative electrode tabs 260 can be attached to the negative electrode 120. The negative electrode 120 may include first to third negative electrode blank sections 621, 622, 623, and first and second negative electrode coated sections 611, 612. The first negative electrode blank section 621 may be positioned towards the winding center (C) with respect to the third negative electrode blank section 623. The second negative electrode blank section 622 may be positioned towards the winding outer section (O) with respect to the third negative electrode blank section 623. The first negative electrode coated section 611 may be positioned between the first negative electrode blank section 621 and the third negative electrode blank section 623. The second negative electrode coated section 612 may be positioned between the second negative electrode blank section 622 and the third negative electrode blank section 623. Since a signal transmission path can be formed in both directions between the negative electrode tab 260 attached to the first negative electrode blank portion 621 and the negative electrode tab 260 attached to the third negative electrode blank portion 623, and the first negative electrode coating portion 611, current can be supplied in both directions. Since a signal transmission path can be formed in both directions between the negative electrode tab 260 attached to the second negative electrode blank portion 622 and the negative electrode tab 260 attached to the third negative electrode blank portion 623, and the second negative electrode coating portion 612, current can be supplied in both directions.

[0081] The negative electrode conductive member 210 can be attached to areas of the negative electrode 120 where there is a risk of wire breakage. The negative electrode conductive member 210 can be attached so as to cover the steps between the first negative electrode coated portion 611 and the first negative electrode plain portion 621, the steps between the first negative electrode coated portion 611 and the third negative electrode plain portion 623, the steps between the third negative electrode plain portion 623 and the second negative electrode coated portion 621, and the steps between the second negative electrode coated portion 621 and the second negative electrode plain portion 622. As a result, even if a crack or / or wire breakage occurs in the negative electrode current collector due to a crack, the electrical connection between the negative electrode coated portions 611, 612 and the negative electrode tab 260 can be maintained via the negative electrode conductive member 210.

[0082] On the other hand, the positive electrode 110, positive electrode tab 250, and positive electrode conductive member 220 shown in Figure 6c are substantially the same as the positive electrode 110, positive electrode tab 250, and positive electrode conductive member 220 shown in Figure 6b, so the explanation of Figure 6b will apply mutatis mutandis.

[0083] Figure 7 is an exploded perspective view illustrating in detail the plain section located in the middle of the winding as shown in Figures 6a to 6c.

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

[0085] The number of conductive members 710 can be determined according to the positions of the ends of the first active material layer 721 and the second active material layer 722, respectively. As an example, the ends of the first active material layer 721 and the second active material layer 722 can be positioned on different imaginary vertical lines. In this case, cracks due to the step difference between the first active material layer 721 and the current collector 723, and cracks due to the step difference between the second active material layer 722 and the current collector 723, can occur at different locations. To prevent disconnection due to cracks occurring at different locations, at least two conductive members 710 can be provided. As another example, the ends of the first active material layer 721 and the second active material layer 722 can be positioned on the same imaginary vertical line. In this case, cracks due to the step difference between the first active material layer 721 and the current collector 723, and cracks due to the step difference between the second active material layer 722 and the current collector 723, can occur at the same location. This allows at least one conductive member 710 to be provided to prevent disconnection due to cracks occurring at the same location.

[0086] The conductive member 710 located in the middle of the winding can include a plurality of conductive members 701, 702, and 703. For example, the conductive member 710 can include a first conductive member 701, a second conductive member 702, and a third conductive member 703.

[0087] Since two steps are formed between the first coated portion 741 and the plain portion 730, located on different virtual vertical lines, a first conductive member 701 and a second conductive member 702 can be placed between the first coated portion 741 and the plain portion 730. The first conductive member 701 can be formed to cover the step between the first active material layer 721 included in the first coated portion 741 and the current collector 723. The second conductive member 702 can be formed to cover the step between the second active material layer 722 included in the first coated portion 741 and the current collector 723.

[0088] Since two steps are formed between the second coated portion 742 and the plain portion 730, which are located on the same virtual vertical line, a third conductive member 703 can be placed between the second coated portion 742 and the plain portion 730. The third conductive member 703 can be formed to cover the step between either the first active material layer 721 or the second active material layer 722 contained in the second coated portion 742 and the current collector 723.

[0089] Even if a crack occurs in the current collector 723, which forms a step with the active material layers 721 and 722, causing a disconnection, 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 a decrease in the performance of the battery cell and ensuring its stability.

[0090] The electrode assemblies described above are not limited to the embodiments shown in each drawing, and the structures shown in each drawing can be applied in combination with each other. A secondary battery including the electrode assembly according to the present invention can employ multiple negative electrodes of any one type described in Figures 3a to 3d, or a combination of negative electrodes described in Figures 3a to 3d. The electrode assembly according to the present invention can employ multiple conductive members of any one type described in Figures 4a to 4c, or a combination of conductive members described in Figures 4a to 4c. The conductive members, including the base layer and adhesive conductive layer shown in Figures 4a to 4c according to the present invention, can be arranged in at least one of the winding center, winding outer casing, and winding intermediate section. The electrode assembly according to the present invention can employ any one positive electrode and negative electrode shown in Figures 6a to 6c, or a combination of positive and negative electrodes described in Figures 6a to 6c. The electrode assembly according to the present invention can apply the winding intermediate section shown in Figure 7 to each embodiment. Although the electrode assembly according to the present invention has been described using a cylindrical secondary battery structure as an example, it is not limited to this, and the conductive member according to the present invention can also be applied to pouch-type or prismatic batteries.

[0091] The secondary battery, including the aforementioned electrode assembly, can be applied to a variety of devices. While it can be applied to transportation methods such as electric bicycles, electric vehicles, and hybrids, it is not limited to these; it can be applied to a wide range of devices where battery modules are available.

[0092] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible by persons with ordinary skill in the art to which the present invention pertains, within a scope equivalent to the technical concept of the present invention and the claims described later. [Explanation of Symbols]

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

Claims

1. Positive electrode and negative electrode, A separator positioned between the positive electrode and the negative electrode, A plurality of conductive members disposed between at least one of the positive electrode and the negative electrode and the separator, Includes, At least one of the positive electrode and the negative electrode is Current collector and, A first active material layer is disposed on the inner surface of the current collector, A second active material layer is disposed on the outer surface of the current collector, Includes, The conductive member is A first conductive member formed so as to overlap with the end of the first active material layer and forming a first conductive path with the current collector, A second conductive member is formed so as to overlap with the end of the second active material layer and forms a second conductive path between the current collector and the second active material layer, Includes, The first conductive member and the second conductive member are arranged on the outer surface of the current collector, spaced apart from each other. The first conductive path and the second conductive path are electrically connected. Electrode assembly.

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

3. The conductive member is A substrate layer disposed between the separator and the electrode, The electrode assembly according to claim 1, comprising: an adhesive conductive layer disposed on the substrate layer, containing a first conductive material, and adhering to the electrode.

4. The first conductive material is, The electrode assembly according to claim 3, which is formed from the same material as the current collector and is arranged in a dot, linear, or patterned manner.

5. The electrode assembly according to claim 3, wherein the first conductive material comprises at least one metal powder selected from Al, Cu, Ni, Au, and Pt.

6. The electrode assembly according to claim 3, wherein the substrate layer comprises at least one of a second conductive material and an insulating material.

7. At least one of the first conductive member and the second conductive member is attached between either the first active material layer or the second active material layer and the current collector. The electrode assembly according to claim 6, wherein the substrate layer comprises at least one of a polymer and a carbon-based material.

8. 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 according to claim 6, wherein the substrate layer comprises at least one of Al, Cu, and fabric.

9. The electrode assembly according to claim 6, wherein the first conductive material is electrically connected to the second conductive material.

10. The electrode is The coating portion includes the current collector, the first active material layer, and the second active material layer, It is divided into a plain section 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 according to claim 1, wherein an electrode tab is attached to the plain portion of the electrode.

11. At least one of the first conductive member and the second conductive member is The electrode assembly according to claim 10, formed between at least one of the two sides of the electrode tab and the current collector.

12. The electrode assembly according to claim 10, further comprising a third conductive member disposed on the plain portion of the negative electrode and positioned at a location corresponding to the winding end portion of the positive electrode.

13. The electrode assembly according to claim 12, wherein the third conductive member is arranged on the same plane as at least a portion of the first conductive member.

14. The first conductive member is It is formed to cover the winding end portion of the first active material layer contained in the negative electrode, The second conductive member is The electrode assembly according to claim 1, which is formed to cover the winding end portion of the second active material layer contained in the negative electrode.

15. A secondary battery comprising an electrode assembly according to any one of claims 1 to 14.

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