Abstract: A button-type secondary battery including an electrode assembly having a first and second electrode tabs; a lower can having an accommodation part, in which the electrode assembly is accommodated and to which the first electrode tab is connected, and a flange part on an outer circumferential surface of the accommodation part; an upper cap on the accommodation part covering the accommodation part and a curl part on an outer circumferential surface of the cover part; a terminal member coupled to the upper cap and connected to the second electrode tab; and an insulating member configured to insulate the terminal member and the upper cap from each other and seal a gap between the terminal member and the upper cap. The flange part and the curl part are coupled to each other in a seaming manner to seal a gap between the lower can and the upper cap.

Abstract: A button-type secondary battery includes an electrode assembly; a lower can having an accommodation space in which the electrode assembly is accommodated; an upper can coupled to the lower can to cover the accommodation space; a gasket sealing a gap between the lower can and the upper can and to electrically insulate the lower can from the upper can while being inserted into a coupled portion of the lower can and the upper can; and a first electrode tab including a first coupling part coupled to a first electrode of the electrode assembly and a second coupling part coupled between the gasket, which is disposed at the coupled portion of the lower can and the upper can, and the upper can. The second coupling part is coupled between the gasket and the upper can by a pressure generated when the lower and upper cans are coupled to each other.

Abstract: The present invention relates to a button-type secondary battery comprising: a can assembly configured to accommodate an electrode assembly and an electrolyte, wherein the can assembly comprises: a lower can configured to accommodate the electrode assembly and the electrolyte and serve as a first electrode terminal; an upper can coupled to surround the lower can and configured to serve as a second electrode terminal; and a gasket provided between the lower can and the upper can to seal a gap between the lower can and the upper can, wherein a first leakage detection member configured to detect whether the electrolyte leaks is provided on an outer surface of the lower can that is in close contact with the gasket, and the first leakage detection member is provided with a recessed lower coupling groove formed in the outer surface of the lower can.

Abstract: The present invention provides a lithium secondary battery, comprising a cathode, an anode, a non-aqueous solution containing a lithium salt and an organic solvent, and a safety vent for removing increased internal pressure, the non-aqueous solution having the prescribed composition and the safety vent having the prescribed operational characteristics. The lithium secondary battery of the present invention can ensure its safety even when overcharged.

Abstract: The present invention provides a lithium secondary battery, comprising a cathode, an anode, a non-aqueous solution containing a lithium salt and an organic solvent, and a safety vent for removing increased internal pressure, the non-aqueous solution having the prescribed composition and the safety vent having the prescribed operational characteristics. The lithium secondary battery of the present invention can ensure its safety even when overcharged.

Abstract: Disclosed are a non-aqueous electrolyte solution for a lithium secondary battery and a lithium secondary battery comprising the same. The non-aqueous electrolyte solution for a lithium secondary battery may include difluorotoluene having a lowest oxidation potential among components of the non-aqueous electrolyte solution. The lithium secondary battery may have improvement in basic performance including high rate charge/discharge characteristics, cycle life characteristics, and the like, and may remarkably reduce swelling caused by decomposition of an electrolyte solution under high voltage conditions such as overcharge.

Abstract: Disclosed are a non-aqueous electrolyte solution for a lithium secondary battery and a lithium secondary battery comprising the same. The non-aqueous electrolyte solution for a lithium secondary battery may include difluorotoluene having a lowest oxidation potential among components of the non-aqueous electrolyte solution. The lithium secondary battery may have improvement in basic performance including high rate charge/discharge characteristics, cycle life characteristics, and the like, and may remarkably reduce swelling caused by decomposition of an electrolyte solution under high voltage conditions such as overcharge.