# US 12,002,922 B2 · Electrode assembly having high flexibility and battery cell including the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,002,922 B2 - Document ID: US12002922B2 - Status: Granted - Kind: B2 - Application number: 15/767,541 - Filed: 2017-03-31 - Published: 2018-10-04 - Granted: 2024-06-04 - Earliest claimed: 2016-03-31 - Assignees: LG Energy Solution, Ltd. - Applicants: LG Chem, Ltd. - Inventors: Min Kyu You; Sung Joong Kang; Ji Young Kim - Web page: https://patentgrep.com/patent/US12002922B2 ## CPC - H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries - H01M 10/0431: {Cells with wound or folded electrodes (H01M10/045 takes precedence)} - H01M 10/0436: {Small-sized flat cells or batteries for portable equipment} - H01M 10/0587: of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators - H01M 50/105: Pouches or flexible bags - H01M 50/136: Flexibility or foldability - H01M 50/46: Separators, membranes or diaphragms characterised by their combination with electrodes - Y02E 60/10: Energy storage using batteries - Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product - Y02T 10/70: Energy storage systems for electromobility, e.g. batteries - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract The present invention provides an electrode assembly having a one directionally spiral-wound structure with a separator sheet interposed between a positive electrode sheet and a negative electrode sheet, wherein the electrode assembly has a horizontal length (x) equal to or more than three times a vertical length (y), and both side end portions of the electrode assembly are bent together in the same direction by a curvature radius (R) satisfying the following Equation 1: S[{1/ln(x/y)}*t]=R 1 wherein t is an average thickness (mm) of the spiral-wound electrode assembly, x is the horizontal length of the electrode assembly, and y is the vertical length of the electrode assembly, and S is a constant of 8 or more, and ln(x/y)≥1. ## Claims ### Claim 1 An electrode assembly having a one directionally spiral-wound structure with a separator sheet interposed between a positive electrode sheet and a negative electrode sheet, the positive electrode sheet and the negative electrode sheet being wound about a winding axis extending in first and second opposite vertical directions, wherein the spiral-wound structure of the electrode assembly has a length (x) in a horizontal direction perpendicular to the winding axis and a height (y) in the first vertical direction, and the spiral-wound structure of the electrode assembly has first and second opposite ends that are separated by the length (x) in the horizontal direction, and a center that is equidistant between the first and second opposite ends, wherein the spiral-wound structure of the electrode assembly is configured to be bent about a bending axis extending in the first and second opposite vertical directions, the bending axis being parallel to the winding axis, the spiral-wound structure having a naturally curved shape having a curvature radius (R) naturally formed without additional external force, the curvature radius (R) relative to the bending axis satisfying the following Equation 1: S[{1/ln(x/y)}*t]=R 1 wherein t is an average thickness (mm) of the spiral-wound electrode assembly in radial directions extending perpendicularly from the bending axis toward the spiral-wound structure and S is a constant of 8 or more, and wherein the spiral-wound structure of the electrode assembly is configured to be repeatedly movable between two positions including a position in which opposing sides of the electrode assembly have a planar shape parallel to one another and in which the first and second opposite ends of the spiral-wound structure of the electrode assembly are spaced apart from the bending axis by a first distance that is greater than the curvature radius (R) and the center is spaced apart from the bending axis by a second distance that is equal to the curvature radius (R), and a position having the naturally curved shape in which the spiral-wound structure of the electrode assembly is bent about the bending axis according to the Equation 1 and in which the first and second opposite ends and the center of the spiral-wound structure of the electrode assembly are spaced apart from the bending axis by a second distance that is equal to the curvature radius (R). ### Claim 2 (depends on 1) The electrode assembly of claim 1, wherein the curvature radius (R) is 5 mm to 20 mm. ### Claim 3 (depends on 1) The electrode assembly of claim 1, wherein the length (x) in the horizontal direction perpendicular to the winding axis is 50 mm to 500 mm. ### Claim 4 (depends on 1) The electrode assembly of claim 1, wherein a positive electrode lead and a negative electrode lead protrude side by side from the spiral-wound structure of the electrode assembly in the first vertical direction. ### Claim 5 (depends on 1) The electrode assembly of claim 1, wherein S is a constant of 9 to 12. ### Claim 6 (depends on 1) The electrode assembly of claim 1, wherein the electrode assembly has a structure having relatively increased flexibility for deformation into a curved shape by dispersing stress in a direction of the relatively long horizontal length. ### Claim 7 (depends on 1) The electrode assembly of claim 1, wherein the spiral-wound structure of the electrode assembly includes winding of the positive electrode sheet and the negative electrode sheet about the winding axis five times or less. ### Claim 8 A battery cell having a structure in which an electrode assembly is stored in a flexible battery case together with an electrolyte solution, wherein the electrode assembly has a one directionally spiral-wound structure with a separator sheet interposed between a positive electrode sheet and a negative electrode sheet, the positive electrode sheet and the negative electrode sheet being wound about a winding axis extending in first and second opposite vertical directions, wherein the spiral-wound structure of the electrode assembly has a length (x) in a horizontal direction perpendicular to the winding axis and a height (y) in the first vertical direction, and the spiral-wound structure of the electrode assembly has first and second opposite ends that are separated by the length (x) in the horizontal direction, and a center that is equidistant between the first and second opposite ends, wherein the spiral-wound structure of the electrode assembly is configured to be bent about a bending axis extending in the first and second opposite vertical directions, the bending axis being parallel to the winding axis, the spiral-wound structure having a naturally curved shape having a curvature radius (R) naturally formed without additional external force, the curvature radius (R) relative to the bending axis satisfying the following Equation 1: S[{1/ln(x/y)}*t]=R 1 wherein t is an average thickness (mm) of the spiral-wound electrode assembly in radial directions extending perpendicularly from the bending axis toward the spiral-wound structure and S is a constant of 8 or more, wherein the spiral-wound structure of the electrode assembly is configured to be repeatedly movable between two positions including a position in which opposing sides of the electrode assembly have a planar shape parallel to one another and in which the first and second opposite ends of the spiral-wound structure of the electrode assembly are spaced apart from the bending axis by a first distance that is greater than the curvature radius (R) and the center is spaced apart from the bending axis by a second distance that is equal to the curvature radius (R), and a position having the naturally curved shape in which the spiral-wound structure of the electrode assembly is bent about the bending axis according to the Equation 1 and in which the first and second opposite ends and the center of the spiral-wound structure of the electrode assembly are spaced apart from the bending axis by a second distance that is equal to the curvature radius (R), and wherein a curved surface is formed on an outer surface of the flexible battery case when the spiral-wound structure is in the naturally curved shape. ### Claim 9 A method of forming a flexible battery cell comprising an electrode assembly stored in a flexible battery case, the method comprising: forming a spiral-wound structure of the electrode assembly having a one directionally spiral-wound structure with a separator sheet interposed between a positive electrode sheet and a negative electrode sheet, the spiral-wound structure having a length (x) in a horizontal direction perpendicular to a winding axis and a height (y) in the first vertical direction, the spiral-wound structure being configured to be repeatedly moved between two positions including a first position and a second position having a naturally curved shape in which the spiral-wound structure is bent about a bending axis extending in the first and second opposite vertical directions, the bending axis being parallel to the winding axis; before the forming of the spiral-wound structure, selecting the length (x) and the height (y) such that the spiral-wound structure in the stably curved position has a curvature radius (R) relative to the bending axis satisfying the following Equation 1: S[{1/ln(x/y)}*t]=R 1 wherein t is an average thickness (mm) of the spiral-wound electrode assembly in radial directions extending perpendicularly from the bending axis toward the spiral-wound structure and S is a constant of 8 or more; and inserting the spiral-wound structure into the flexible battery case together with an electrolyte solution, the flexible battery case being configured such that an outer surface of the flexible battery cell has a curved shape when the spiral-wound structure is in the naturally curved shape.