A top cover assembly for a battery, a battery, and an energy storage device are provided in the disclosure. The top cover assembly includes an insulating cover plate, a top cover plate, an insulating member, and a current collector stacked in sequence. A surface of the first flange close to the insulating member, an inner circumferential wall of the mounting hole, and a surface of the top cover plate close to the first flange and extending beyond the inner circumferential wall of the mounting hole define a sealing cavity. An inner circumferential wall of the through hole and an outer circumferential wall of the main body define a gap therebetween, the gap communicates with the sealing cavity, and a sealing member is received in the sealing cavity.

A top cover assembly for a battery, a battery, and an energy storage device are provided in the disclosure. The top cover assembly includes an insulating cover plate, a top cover plate, an insulating member, and a current collector stacked in sequence. A surface of the first flange close to the insulating member, an inner circumferential wall of the mounting hole, and a surface of the top cover plate close to the first flange and extending beyond the inner circumferential wall of the mounting hole define a sealing cavity. An inner circumferential wall of the through hole and an outer circumferential wall of the main body define a gap therebetween, the gap communicates with the sealing cavity, and a sealing member is received in the sealing cavity.

The present disclosure provides a battery cap assembly and a secondary battery. The battery cap assembly comprises a cap plate, a first electrode terminal and a first connecting piece. The cap plate is made of insulating material and includes a first terminal hole; the first electrode terminal is provided to the cap plate and extends into the first terminal hole; the first connecting piece is provided below the cap plate. The first connecting piece includes a first connecting portion connected with the first electrode terminal, an upper surface of the first connecting portion is attached to the cap plate. The secondary battery comprises an electrode assembly, a case and the battery cap assembly. The case receives the electrode assembly and has an opening. The cap plate is connected with the case, the first connecting portion of the first connecting piece is electrically connected with the first electrode plate.

The present disclosure relates to an energy storage device comprising: a housing for accommodating an electrolyte; an electrode element accommodated inside the housing; a case coupled to one side of the housing; and an electrode terminal inserted into the case so as to be electrically connected to the electrode element, wherein the case comprises: a base part having a through-hole into which the electrode terminal is inserted; and a sealing part coupled to the base part so as to seal the space between the base part and the electrode terminal, and the sealing part includes a terminal sealing member located at the through-hole so as to come into close contact with the electrode terminal, thereby sealing the space between the base part and the electrode terminal.

The present disclosure relates to an energy storage device comprising: a housing for accommodating an electrolyte; an electrode element accommodated inside the housing; a case coupled to one side of the housing; and an electrode terminal inserted into the case so as to be electrically connected to the electrode element, wherein the case comprises: a base part having a through-hole into which the electrode terminal is inserted; and a sealing part coupled to the base part so as to seal the space between the base part and the electrode terminal, and the sealing part includes a terminal sealing member located at the through-hole so as to come into close contact with the electrode terminal, thereby sealing the space between the base part and the electrode terminal.

Disclosed is a battery cell, which includes a battery case having an accommodation portion in which a battery assembly is positioned, and a sealing portion formed by sealing an outer periphery thereof by heat fusion; an electrode lead electrically connected to an electrode tab included in the battery assembly, the electrode lead protruding out of the battery case through the sealing portion; and a lead film positioned adjacent to the sealing portion on at least one of a first side and a second side of the electrode lead, wherein the lead film includes a gas discharge portion formed to extend from an inside of the battery case to an outside of the battery case, and the gas discharge portion is opened on a side disposed inside of the battery case.

A cylindrical secondary battery includes: an electrode assembly including a first electrode plate and a second electrode plate; a can having a bottom part and a cylindrical side part, configured to accommodate the electrode assembly, and electrically connected to the first electrode plate; and a cap assembly. The cap assembly includes: a cap plate coupled to one end of the cylindrical side part and electrically connected to the cylindrical side part; and a rivet terminal insulated from the cap plate and electrically connected to the second electrode plate.

A secondary battery with a reduced degree of increase in internal pressure over time, is provided. In a preferred embodiment, a secondary battery including: an electrode body, a battery case, an electrode terminal, and a gasket sandwiched between the battery case and the electrode terminal is provided. The secondary battery is configured such ghat a parameter K calculated using the following equation (1): K=Wi/(VrG.sub.H2) (1) (where Wi represents an initial capacity (Ah) of the secondary battery, Yr represents a volume (cm.sup.3) of void in the battery case, and G.sub.H2, represents an H.sub.2 gas permeability coefficient (cm.sup.3.Math.cm)/(cm.sup.2.Math.s.Math.cmHg) of the gasket at 60° C.) satisfies 0.43×10.sup.8 or more to 0.59×10.sup.8 or less.

A secondary battery with a reduced degree of increase in internal pressure over time, is provided. In a preferred embodiment, a secondary battery including: an electrode body, a battery case, an electrode terminal, and a gasket sandwiched between the battery case and the electrode terminal is provided. The secondary battery is configured such ghat a parameter K calculated using the following equation (1): K=Wi/(VrG.sub.H2) (1) (where Wi represents an initial capacity (Ah) of the secondary battery, Yr represents a volume (cm.sup.3) of void in the battery case, and G.sub.H2, represents an H.sub.2 gas permeability coefficient (cm.sup.3.Math.cm)/(cm.sup.2.Math.s.Math.cmHg) of the gasket at 60° C.) satisfies 0.43×10.sup.8 or more to 0.59×10.sup.8 or less.

A battery, a battery pack, and a vehicle are disclosed. The battery includes a housing having a sealed chamber, a core packaged in the sealed chamber, and a first terminal and a second terminal respectively mounted to the housing, where the first terminal is electrically connected to the housing, and the second terminal is insulated from the housing. The battery further includes a first tab and a second tab respectively led out from the core, the first tab being electrically connected to the housing, the first tab being electrically connected to the first terminal through the housing, and the second tab being electrically connected to the second terminal.