Abstract: A steel sheet for a battery case includes about 0.02 wt % to about 0.08 wt % carbon (C); about 0.01 wt % to about 0.1 wt % niobium (Nb); and the balance of iron (Fe). Further aspects provide for a battery case manufactured from the steel sheet for a battery case and provided with an opening. Further aspects provide for a cylindrical secondary battery comprising a cylindrical case manufactured from the steel sheet for a battery case, a cap assembly sealing the cylindrical case, and an electrode assembly disposed inside the cylindrical case.

Abstract: An embodiment of the present invention relates to a cylindrical secondary battery, and the cylindrical secondary battery may comprise: a cylindrical can; an electrode assembly which includes a first electrode plate, a second electrode plate, and a separator wound together and is accommodated in the can; and a cap assembly which is insulated from the can, is electrically connected to the electrode assembly, and has a hole formed therethrough to communicate with the inside of the can. According to the embodiment of the present invention, a degassing function is applied so that gas generated before product delivery can be removed and thus deformation of the can and the cap assembly can be reduced. In addition, the occurrence of swelling of the electrode assembly due to internal gas generation can be prevented and thus performance degradation of the secondary battery can be reduced.

Abstract: Provided is a cylindrical secondary battery. The cylindrical secondary battery includes a cylindrical can, an electrode assembly in which a first electrode plate, a second electrode plate, and a separator are wound and which is accommodated in the can, and a cap assembly which is insulated from the can and electrically connected to the electrode assembly and through which a degassing hole passes to communicate with the inside of the can. According to the embodiment, since a degassing function is applied to remove the gas generated before the product shipment, deformation of the can and the cap assembly may be reduced. In addition, swelling of the electrode assembly due to the generation of the internal gas may be prevented from occurring to reduce performance deterioration of the secondary battery.

Abstract: The present invention relates to a secondary battery capable of improving insulation safety. For example, the secondary battery includes: an electrode assembly; a case configured to accommodate the electrode assembly; and a cap assembly coupled to an upper portion of the case, wherein the cap assembly includes a cap-up, a safety vent installed below the cap-up and having a vent extension part extending to an upper side of the cap-up to surround an edge of the cap-up, and an insulation washer attached to upper portions of the vent extension part and the cap-up, and a welding area having a thickness less than that of surroundings is formed on the vent extension part.

Abstract: Disclosed herein is a cylindrical secondary battery including a cap assembly constructed in a structure in which a vent, which intercepts electric current and discharges pressurized gas when the interior pressure of the battery is increased due to abnormal operation of the battery, is in contact with a top cap having a protruding central part, wherein the end of the vent is bent to surround the outer circumferential surface of the top cap, and a groove for preventing the leakage of an electrolyte and preventing the occurrence of defectiveness of the battery during the assembly of the battery is formed at interfaces between the vent and the top cap such that the groove is arranged in parallel with the outer circumferential surface of the top cap.

Abstract: Disclosed herein is a cylindrical secondary battery constructed in a structure in which a crimping region, at which a cap assembly is mounted to the open upper end of a cylindrical container having an electrode assembly mounted therein, is formed at the upper end of the container, wherein the crimping region is constructed in a structure in which the upper end of the crimping region is gently bent at a predetermined radius of curvature (R), such that the crimping region surrounds a gasket located at the inside of the crimping region, the bent front end extends inward, such that the bent end presses the gasket, and an inclination of a predetermined angle is formed at the sidewall of the crimping region, such that the upper part of the crimping region is directed inward. According to the secondary battery of the present invention, the sealability of the gasket is improved, and external impacts are partially absorbed by the inclination formed at the crimping region.

Abstract: Disclosed herein is a cylindrical secondary battery constructed in a structure in which a crimping region, at which a cap assembly is mounted to the open upper end of a cylindrical container having an electrode assembly mounted therein, is formed at the upper end of the container, wherein the crimping region is constructed in a structure in which the upper end of the crimping region is gently bent at a predetermined radius of curvature (R), such that the crimping region surrounds a gasket located at the inside of the crimping region, the bent front end extends inward, such that the bent end presses the gasket, and an inclination of a predetermined angle is formed at the sidewall of the crimping region, such that the upper part of the crimping region is directed inward. According to the secondary battery of the present invention, the sealability of the gasket is improved, and external impacts are partially absorbed by the inclination formed at the crimping region.

Abstract: Disclosed herein is a cylindrical secondary battery including a cap assembly constructed in a structure in which a vent, which intercepts electric current and discharges pressurized gas when the interior pressure of the battery is increased due to abnormal operation of the battery, is in contact with a top cap having a protruding central part, wherein the end of the vent is bent to surround the outer circumferential surface of the top cap, and a groove for preventing the leakage of an electrolyte and preventing the occurrence of defectiveness of the battery during the assembly of the battery is formed at interfaces between the vent and the top cap such that the groove is arranged in parallel with the outer circumferential surface of the top cap.