# US 12,015,117 B2 · Lithium secondary cell > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,015,117 B2 - Document ID: US12015117B2 - Status: Granted - Kind: B2 - Application number: 17/302,872 - Filed: 2021-05-14 - Published: 2021-08-26 - Granted: 2024-06-18 - Earliest claimed: 2018-12-18 - Assignees: NGK Insulators, Ltd. - Applicants: Ngk Insulators, Ltd. - Inventors: Daisuke Iida; Eiji Nakashima; Yuuki Fujita - Web page: https://patentgrep.com/patent/US12015117B2 ## CPC - H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries - H01M 4/04: Processes of manufacture in general - H01M 4/131: Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx - H01M 4/664: {Ceramic materials} - H01M 10/0436: {Small-sized flat cells or batteries for portable equipment} - H01M 10/0567: characterised by the additives - H01M 10/0585: of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators - H01M 50/105: Pouches or flexible bags - H01M 50/202: Casings or frames around the primary casing of a single cell or a single battery - H01M 50/238: Flexibility or foldability - H01M 50/247: specially adapted for portable devices, e.g. mobile phones, computers, hand tools or pacemakers - H01M 2300/0025: Organic electrolyte - Y02E 60/10: Energy storage using batteries - Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product - 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 ## Abstract A lithium secondary cell includes a positive electrode, a separator, a negative electrode, an electrolytic solution, and a cell case. The positive electrode, the negative electrode, and the separator are impregnated with the electrolytic solution. The cell case is a sheet-like member and convers the positive electrode and the negative electrode from both sides in the direction of superposition. The cell case houses therein the positive electrode, the separator, the negative electrode, and the electrolytic solution. The electrolytic solution contains an electrolytic solution material serving as a base compound and LiDFOB serving as an additive. The moisture content in the electrolytic solution is higher than or equal to 10 ppm by mass and lower than or equal to 15 ppm by mass. ## Claims ### Claim 1 A lithium secondary cell comprising: a positive electrode; a separator arranged on said positive electrode in a predetermined direction of superposition; a negative electrode arranged on said separator on a side opposite to said positive electrode in said direction of superposition; an electrolytic solution with which said positive electrode, said negative electrode, and said separator are impregnated; and a sheet-like cell case that covers said positive electrode and said negative electrode from both sides in said direction of superposition and houses therein said positive electrode, said separator, said negative electrode, and said electrolytic solution, wherein said electrolytic solution contains: an electrolytic solution material serving as a base compound; and lithium difluoro(oxalato)borate and fluoroethylene carbonate serving as additives, said electrolytic solution has a content of fluoroethylene carbonate that is equal to or less than a content of lithium difluoro(oxalato)borate, and said electrolytic solution has a moisture content higher than or equal to 10 ppm by mass and lower than or equal to 15 ppm by mass. ### Claim 2 (depends on 1) The lithium secondary cell according to claim 1, wherein said electrolytic solution has a content of said lithium difluoro(oxalato)borate higher than or equal to 0.1 percent by mass and lower than or equal to 4 percent by mass. ### Claim 3 (depends on 1) The lithium secondary cell according to claim 1, wherein reaction resistance per unit reaction area is higher than or equal to 3.5 Ω·cm2 and lower than or equal to 5.8 Ω·cm2. ### Claim 4 (depends on 1) The lithium secondary cell according to claim 1, wherein said positive electrode includes: a sheet-like current collector having conductivity; and an active material plate that is a plate-like ceramic sintered body containing a lithium composite oxide. ### Claim 5 (depends on 4) The lithium secondary cell according to claim 4, wherein said active material plate has a structure in which primary particles having a layered rock-salt structure are coupled together, said primary particles have an average inclination angle greater than 0° and less than or equal to 30°, and said average inclination angle is an average value of angles formed by (003) planes of said primary particles and a main surface of said active material plate. ### Claim 6 (depends on 1) The lithium secondary cell according to claim 1, being used as a power supply source of a sheet-like device or a device having flexibility. ### Claim 7 (depends on 6) The lithium secondary cell according to claim 6, being used as a power supply source of a smart card that is said device having flexibility.