# US 8,771,860 B2 · Lithium secondary battery and method for manufacturing same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,771,860 B2 - Document ID: US8771860B2 - Status: Granted - Kind: B2 - Application number: 13/122,173 - Filed: 2010-06-11 - Published: 2013-04-25 - Granted: 2014-07-08 - Earliest claimed: 2010-06-11 - Assignees: Toyota Jidosha Kabushiki Kaisha - Applicants: Tomoyoshi Ueki; Yusuke Fukumoto; Harunari Shimamura - Inventors: Tomoyoshi Ueki; Yusuke Fukumoto; Harunari Shimamura - Web page: https://patentgrep.com/patent/US8771860B2 ## CPC - H01M 10/0431: {Cells with wound or folded electrodes (H01M10/045 takes precedence)} - H01M 4/13: Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof - H01M 4/139: Processes of manufacture - H01M 4/366: {as layered products} - H01M 10/052: Li-accumulators - H01M 10/0587: of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators - H01M 50/451: comprising layers of only organic material and layers containing inorganic material - H01M 50/457: comprising three or more layers - H01M 50/489: Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties - 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 - Y10T 29/49115: including coating or impregnating - 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 - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A lithium secondary battery provided by the present invention includes a spirally wound electrode body in which a positive electrode sheet and a negative electrode sheet are spirally wound with a separator sheet 40 interposed therebetween, wherein on a sheet surface of at least any one from among the positive electrode sheet, negative electrode sheet, and separator sheet 40 constituting the spirally wound electrode body, a porous layer 60 is formed along a longitudinal direction of the sheet 40, and the porous layer 60 is thicker in a spiral winding direction of the spirally wound electrode body in a winding center portion 62 than in a winding outer portion 64. ## Claims ### Claim 1 A lithium secondary battery comprising an electrode body having a positive electrode sheet and a negative electrode sheet being wound with a separator sheet, the separator sheet being between the positive electrode sheet and the negative electrode sheet, wherein a porous layer is formed on a surface of at least one of the positive electrode sheet, the negative electrode sheet, and the separator sheet, and wherein the porous layer formed on a winding start side of the surface is thicker than the porous layer formed on a winding end side of the surface. ### Claim 2 (depends on 1) The lithium secondary battery according to claim 1, wherein an average thickness of the porous layer formed in an area of up to 20% of the sheet from an end portion on the winding start side is larger than an average thickness of the porous layer formed in an area of up to 20% from an end portion on the winding end side. ### Claim 3 (depends on 1) The lithium secondary battery according to claim 1, wherein the porous layer is formed such as to increase gradually in thickness from the winding end side to the winding start side of the sheet. ### Claim 4 (depends on 1) The lithium secondary battery according to claim 1, wherein the porous layer has a thickest portion with a largest thickness and a thinnest portion with a smallest thickness, and a difference in thickness between the thickest portion and the thinnest portion is 2 μm to 4 μm. ### Claim 5 (depends on 1) The lithium secondary battery according to claim 1, wherein a porosity of the porous layer is 45% to 65% ### Claim 6 (depends on 1) The lithium secondary battery according to claim 1, wherein the porous layer is constituted by metal compound particles. ### Claim 7 (depends on 1) The lithium secondary battery according to claim 1, wherein the porous layer is formed on a surface of the separator sheet. ### Claim 8 (depends on 7) The lithium secondary battery according to claim 7, wherein the porous layer is formed on a surface of the separator sheet on a negative electrode sheet side. ### Claim 9 (depends on 1) A method for manufacturing the lithium secondary battery according to claim 1, the method comprising the step of: coating and drying a coating material for forming a porous layer with coating means on a surface of at least any one traveling sheet from among a positive electrode sheet, negative electrode sheet, and separator sheet to form the porous layer, wherein the coating material for forming a porous layer is coated, while changing a traveling speed of the sheet. ### Claim 10 (depends on 9) The manufacturing method according to claim 9, wherein the coating means is a gravure roll, and the coating material for forming a porous layer is coated, while changing a rotation speed of the gravure roll. ### Claim 11 (depends on 9) The manufacturing method according to claim 9, wherein a porous layer corresponding to a plurality of batteries is continuously formed on the traveling sheet surface. ### Claim 12 (depends on 9) A vehicle equipped with a lithium secondary battery comprising an electrode body having a positive electrode sheet and a negative electrode sheet being wound with a separator sheet, the separator sheet being between the positive electrode sheet and the negative electrode sheet, wherein a porous layer is formed on a surface of at least one of the positive electrode sheet, the negative electrode sheet, and the separator, and wherein the porous layer formed on a winding start side of the surface is thicker than the porous layer formed on a winding end side of the surface, or a lithium secondary battery manufactured by the manufacturing method according to claim 9.