A rechargeable battery pack supplies electrical drive power to an electrically driven machining device. The rechargeable battery pack has: a plurality of rechargeable battery cells, wherein the rechargeable battery cells each have cell contacts; a housing, wherein the rechargeable battery cells are arranged within the housing; and a potting compound, wherein the potting compound protects the cell contacts from contact with water from outside the housing. The housing has a housing top part and a housing bottom part. The housing bottom part overlaps the housing top part such that the housing top part defines an outer region and an inner region of the housing bottom part for the potting compound. A casting level of the potting compound in the outer region is above a casting level of the potting compound in the inner region.

A secondary battery includes: a cylindrical case; an electrode assembly accommodated in the cylindrical case and wound in a cylindrical shape; and a current interrupt device electrically connected to the electrode assembly and sealing the cylindrical case. The current interrupt device includes a cap-down electrically connected to the electrode assembly, a safety vent electrically connected to the cap-down, and an insulating gasket between the cap-down and the safety vent and covering outer circumferences of the cap-down and the safety vent.

A secondary battery includes: a cylindrical case; an electrode assembly accommodated in the cylindrical case and wound in a cylindrical shape; and a current interrupt device electrically connected to the electrode assembly and sealing the cylindrical case. The current interrupt device includes a cap-down electrically connected to the electrode assembly, a safety vent electrically connected to the cap-down, and an insulating gasket between the cap-down and the safety vent and covering outer circumferences of the cap-down and the safety vent.

A battery includes a can, a jelly roll contained in the can, a top insulator contained in the can adjacent to and above the jelly roll, and a battery cap. The battery cap is welded to an inner surface of the can adjacent to and above the top insulator and includes an outer conductive ring, an insulator ring, and a conductive top plate, wherein the outer conductive ring, the insulator ring, and the conductive top plate are crimped together. The battery cap further includes a conductive rupture plate electrically connected to the conductive top plate and a cathode electrically connected to the conductive rupture plate and extending into the jelly roll. The battery may further include an opening in a central portion of the conductive top plate and a central portion of the conductive rupture plate cover welded upon the opening in the central portion of the conductive top plate.

A battery includes a can, a jelly roll contained in the can, a top insulator contained in the can adjacent to and above the jelly roll, and a battery cap. The battery cap is welded to an inner surface of the can adjacent to and above the top insulator and includes an outer conductive ring, an insulator ring, and a conductive top plate, wherein the outer conductive ring, the insulator ring, and the conductive top plate are crimped together. The battery cap further includes a conductive rupture plate electrically connected to the conductive top plate and a cathode electrically connected to the conductive rupture plate and extending into the jelly roll. The battery may further include an opening in a central portion of the conductive top plate and a central portion of the conductive rupture plate cover welded upon the opening in the central portion of the conductive top plate.

A hermetically sealed battery which is an example of an embodiment is provided with: an electrode body having an electrode tab; an outer can in the shape of a bottomed cylinder for accommodating the electrode body; and a sealing body for closing an opening portion of the outer can. The sealing body includes: a first thin-walled portion formed in an annular shape; a valve portion which surrounds the first thin-walled portion, and which deforms in such a way as to protrude to the outside of the battery when the internal pressure in the battery rises; and a linear second thin-walled portion formed in the valve portion. The electrode tab is disposed in such a way as to intersect the second thin-walled portion, and is joined to an inner surface of the valve portion in such a way as to sandwich the second thin-walled portion.

A hermetically sealed battery which is an example of an embodiment is provided with: an electrode body having an electrode tab; an outer can in the shape of a bottomed cylinder for accommodating the electrode body; and a sealing body for closing an opening portion of the outer can. The sealing body includes: a first thin-walled portion formed in an annular shape; a valve portion which surrounds the first thin-walled portion, and which deforms in such a way as to protrude to the outside of the battery when the internal pressure in the battery rises; and a linear second thin-walled portion formed in the valve portion. The electrode tab is disposed in such a way as to intersect the second thin-walled portion, and is joined to an inner surface of the valve portion in such a way as to sandwich the second thin-walled portion.

A battery pack (2000) includes a secondary battery (2020), a sensor (2040), and a control device (2060). The secondary battery (2020) supplies electric power to a flying object (10). The sensor (2040) outputs a measurement value related to a force applied to the secondary battery (2020) or a periphery of the secondary battery. The control device (2060) has a determination unit (2062). The determination unit (2062) determines a danger level of the secondary battery (2020) based on the measurement value of the sensor (2040).

A method for constructing a battery that includes a can, a jelly roll contained in the can, a top insulator contained in the can adjacent to and above the jelly roll, and a battery cap. The method includes forming the can, forming the jelly roll, inserting the jelly roll into the can, inserting a top insulator into the can adjacent to and above the jelly roll, assembling the battery cap, including an outer conductive ring, an insulator ring, a conductive top plate, a conductive rupture plate, connecting a cathode to the conductive rupture plate, inserting the battery cap into the can, and welding the battery cap to an inner surface of the can.

A method for constructing a battery that includes a can, a jelly roll contained in the can, a top insulator contained in the can adjacent to and above the jelly roll, and a battery cap. The method includes forming the can, forming the jelly roll, inserting the jelly roll into the can, inserting a top insulator into the can adjacent to and above the jelly roll, assembling the battery cap, including an outer conductive ring, an insulator ring, a conductive top plate, a conductive rupture plate, connecting a cathode to the conductive rupture plate, inserting the battery cap into the can, and welding the battery cap to an inner surface of the can.