# US 8,785,017 B2 · Secondary battery > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,785,017 B2 - Document ID: US8785017B2 - Status: Granted - Kind: B2 - Application number: 12/855,467 - Filed: 2010-08-12 - Published: 2011-06-23 - Granted: 2014-07-22 - Earliest claimed: 2009-12-23 - Assignees: Samsung SDI Co., Ltd. - Applicants: Chohee Kang; Junsun Yong - Inventors: Chohee Kang; Junsun Yong - Web page: https://patentgrep.com/patent/US8785017B2 ## CPC - H01M 10/0422: {Cells or battery with cylindrical casing} - H01M 50/169: by welding, brazing or soldering - H01M 50/171: using adhesives or sealing agents - H01M 50/30: Arrangements for facilitating escape of gases - H01M 50/342: Non-re-sealable arrangements - H01M 10/0436: {Small-sized flat cells or batteries for portable equipment} - H01M 50/578: in response to pressure - Y02E 60/10: Energy storage using batteries - Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product - Y10T 29/49108: Electric battery cell making - 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 - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract Disclosed is a secondary battery that comprises an electrode assembly, a can accommodating the electrode assembly, and a cap assembly coupled to an upper portion of the can and including an upper cap that transfers a current of the electrode assembly to an exterior of the can. The upper cap includes a terminal part including a first flat portion disposed at a center of the upper cap and a second flat portion extending from a periphery of the first flat portion, a peripheral part disposed at a periphery of the terminal part and stepped from the terminal part, and a connection part connecting the terminal part to the peripheral part. ## Claims ### Claim 1 A secondary battery comprising: an electrode assembly; a can accommodating the electrode assembly; and a cap assembly coupled to an upper portion of the can and including an upper cap that transfers a current of the electrode assembly to an exterior of the can; wherein the upper cap includes a terminal part including a first flat portion disposed at a center of the upper cap and a second flat portion extending from a periphery of the first flat portion, a peripheral part disposed at a periphery of the terminal part and stepped from the terminal part, and a connection part connecting the terminal part to the peripheral part having a gas exhausting hole wherein the gas exhausting hole comprises a first curved portion disposed at a portion where the gas exhausting hole meets the terminal part and a second curved portion disposed at a portion where the gas exhausting hole meets the connection part and the peripheral part wherein the gas exhausting hole extends through a portion of the terminal part and a portion of the peripheral part. ### Claim 2 (depends on 1) The secondary battery as claimed in claim 1, wherein the second flat portion is disposed between the first flat portion and the connection part. ### Claim 3 (depends on 1) The secondary battery as claimed in claim 1, wherein the terminal part has a diameter ranging from about 7 mm to about 8 mm. ### Claim 4 (depends on 1) The secondary battery as claimed in claim 1, wherein the terminal part has a diameter ranging from 40% to about 50% of a diameter of the upper cap. ### Claim 5 (depends on 1) The secondary battery as claimed in claim 1, further comprising a plurality of gas exhausting holes, wherein the number of the gas exhausting holes is at least three. ### Claim 6 (depends on 1) The secondary battery as claimed in claim 1, wherein the second flat portion has a planar surface that is obtained by pressing a curved surface between the first flat portion and the gas exhausting hole. ### Claim 7 (depends on 1) The secondary battery as claimed in claim 1, wherein the second flat portion is disposed at a region between the gas exhausting hole and another gas exhausting hole. ### Claim 8 (depends on 1) The secondary battery as claimed in claim 1, wherein the gas exhausting hole comprises a first curved portion disposed at a portion where the gas exhausting hole meets the terminal part, and a second curved portion disposed at a portion where the gas exhausting hole meets the connection part and the peripheral part, wherein the first curved portion has a radius of curvature ranging from about 1.4 mm to about 1.6 mm, and wherein the second curved portion has a radius of curvature ranging from about 0.1 mm to about 0.3 mm. ### Claim 9 (depends on 1) The secondary battery as claimed in claim 1, wherein the cap assembly comprises: a lower cap installed at an upper portion of the electrode assembly and having a through hole at a center of the lower cap; a safety vent electrically connected to the electrode assembly; and an insulator disposed between the safety vent and the lower cap. ### Claim 10 (depends on 1) The secondary battery as claimed in claim 1, wherein the upper cap is formed of steel plated with nickel. ### Claim 11 A secondary battery comprising: an electrode assembly; a can accommodating the electrode assembly; and a cap that abuts one side of the can comprising a terminal portion at a center of the cap, a peripheral portion substantially parallel to the terminal portion, a connection portion coupling the terminal portion to the peripheral portion, and at least one opening in the connection portion that extends through a part of the terminal portion wherein the at least one opening comprises a gas exhausting hole wherein the gas exhausting hole comprises a first curved portion disposed at a portion where the gas exhausting hole meets the terminal part and a second curved portion disposed at a portion where the gas exhausting hole meets the connection part and the peripheral part, further comprising a plurality of openings in the connection portion, wherein each opening extends through a part of the terminal portion. ### Claim 12 (depends on 11) The secondary battery of claim 11, wherein the terminal portion comprises a first flat portion disposed at a center of the cap, and a second flat portion extending from a periphery of the first flat portion, wherein the second flat portion is obtained by pressing a curved surface between the first flat portion and the at least one opening.