A secondary battery includes: a cylindrical case; an electrode assembly in the cylindrical case; and a cap plate electrically connected to the electrode assembly and sealing the cylindrical case. The cap plate has a first flat portion at a center of the cap plate, a second flat portion outside the first flat portion, and a vent portion between the first flat portion and the second flat portion, and the vent portion has a thickness smaller than a thickness of the first flat portion or a thickness of the second flat portion.

A secondary battery includes: a cylindrical case; an electrode assembly in the cylindrical case; and a cap plate electrically connected to the electrode assembly and sealing the cylindrical case. The cap plate has a first flat portion at a center of the cap plate, a second flat portion outside the first flat portion, and a vent portion between the first flat portion and the second flat portion, and the vent portion has a thickness smaller than a thickness of the first flat portion or a thickness of the second flat portion.

A cylindrical secondary battery includes: a cylindrical can having a circular bottom portion, a side portion extending from the bottom portion, a beading part concavely formed inwardly at one end of the side portion, and a crimping part formed by bending a distal end of the side portion; an electrode assembly in the can; and a cap assembly sealing the can. The cap assembly includes a gasket for insulation from the can, and an upper portion of the gasket in a direction away from the electrode assembly has a smaller thickness than a lower portion of the gasket.

A secondary battery includes: a cylindrical case; an electrode assembly in the cylindrical case; and a cap assembly configured to seal the cylindrical case and including a cap-down electrically connected to the electrode assembly, a cap-up coupled to an upper portion of the cap-down, and a vent plate between the cap-down and the cap-up, wherein the vent plate includes: a first plate; and a second plate coupled to the outside of the first plate, wherein the first plate has rigidity less than that of the second plate.

A secondary battery includes: a cylindrical case; an electrode assembly in the cylindrical case; and a cap assembly configured to seal the cylindrical case and including a cap-down electrically connected to the electrode assembly, a cap-up coupled to an upper portion of the cap-down, and a vent plate between the cap-down and the cap-up, wherein the vent plate includes: a first plate; and a second plate coupled to the outside of the first plate, wherein the first plate has rigidity less than that of the second plate.

A sealed battery, which is an exemplary embodiment, comprises a battery case including a bottomed cylindrical outer can and a sealing body that closes an opening of the outer can, a gasket disposed between the outer can and the sealing body, and an electrode body including an electrode and housed in the battery case. The sealing body includes a metal plate, and the metal plate has a thin portion formed in an annular shape, a valve portion having a convex shape inside the battery case, and an annular portion to which the electrode lead is connected. The gasket is provided with an elastically deformable portion that abuts against the inner surface of the valve portion and urges the valve portion to the outside of the battery case.

A sealed battery, which is an exemplary embodiment, comprises a battery case including a bottomed cylindrical outer can and a sealing body that closes an opening of the outer can, a gasket disposed between the outer can and the sealing body, and an electrode body including an electrode and housed in the battery case. The sealing body includes a metal plate, and the metal plate has a thin portion formed in an annular shape, a valve portion having a convex shape inside the battery case, and an annular portion to which the electrode lead is connected. The gasket is provided with an elastically deformable portion that abuts against the inner surface of the valve portion and urges the valve portion to the outside of the battery case.

The present invention relates to a secondary battery in which a conductive cover, which is electrically connected to a case and has a flat part, is formed at an upper end of the case so as to facilitate welding of an electrode tab and enable space utilization to be maximized. According to one embodiment, disclosed is a secondary battery comprising: an electrode assembly; a case for accommodating the electrode assembly; a cap assembly which is coupled to an upper part of the case so as to seal the case, and has a terminal part; and a conductive cover which is coupled to an upper part of the case and fixed to a lateral plate of the case.

The present invention relates to a secondary battery in which a conductive cover, which is electrically connected to a case and has a flat part, is formed at an upper end of the case so as to facilitate welding of an electrode tab and enable space utilization to be maximized. According to one embodiment, disclosed is a secondary battery comprising: an electrode assembly; a case for accommodating the electrode assembly; a cap assembly which is coupled to an upper part of the case so as to seal the case, and has a terminal part; and a conductive cover which is coupled to an upper part of the case and fixed to a lateral plate of the case.

A secondary battery according to an embodiment includes: an electrode body which contains a positive electrode, a negative electrode, and at least one separator interposed between the positive electrode and the negative electrode; a case main body which receives the electrode body; a sealing body which seals an opening portion of the case main body; and a sealing body-side insulating member provided between the sealing body and one end portion of the electrode body and a case main body-side insulating member; the one end portion and the other end portion of the electrode body each form a protruding section; and the sealing body-side insulating member includes a base material and an adhesive layer which is disposed on the base material and which contains a cured object of a curable resin, and the protruding section of the one end portion of the electrode body is adhered to the adhesive layer.