Abstract: A secondary battery including an electrode wound body having a structure in which a band-shaped positive electrode and a band-shaped negative electrode are stacked and wound with a separator interposed therebetween, an electrolyte solution, a battery can that accommodates the electrode wound body and the electrolyte solution, a battery lid that closes an open end portion of the battery can, and a safety valve mechanism provided between the battery lid and the electrode wound body, wherein the safety valve mechanism includes at least a safety cover, an outer peripheral portion of the battery lid and an outer peripheral portion of the safety cover are joined, and an area of a region where the outer peripheral portion of the battery lid and the outer peripheral portion of the safety cover are joined is 18.1% or more and 25.0% or less of a sectional area of the battery in a radial direction.

Abstract: There is provided a secondary battery in which a positive electrode and a negative electrode are laminated with a separator interposed therebetween, and an electrode winding body having a wound structure, an electrolytic solution, and a positive electrode tab connected to the positive electrode are accommodated in an outer can. An insulator is disposed in proximity to an end on a side of the positive electrode tab of the electrode winding body. The electrode winding body and the insulator each have a center hole. A diameter or size of the center hole of the insulator is larger than a diameter of the center hole of the electrode winding body and is smaller than 1.1 times a width of the positive electrode tab.

Abstract: A battery includes a safety valve configured to cause a deformation due to an increase in internal pressure of the battery; a restraining part including a plurality of first protrusions provided along a first circumference to serve as a restrainer against a lead part when the safety valve and the lead part are shut off due to deformation of the safety valve; and an insulating holder including a plurality of second protrusions provided along a second circumference to insulate the safety valve and the restraining part, where a number of the first protrusions and the second protrusions arranged on a diagonal line including the first circumference and the second circumference is 3 or less.

Abstract: A battery includes a safety valve configured to cause a deformation due to an increase in internal pressure of the battery; a restraining part including a plurality of first protrusions provided along a first circumference to serve as a restrainer against a lead part when the safety valve and the lead part are shut off due to deformation of the safety valve; and an insulating holder including a plurality of second protrusions provided along a second circumference to insulate the safety valve and the restraining part, where a number of the first protrusions and the second protrusions arranged on a diagonal line including the first circumference and the second circumference is 3 or less.

Abstract: A battery includes: a battery element having a cathode and an anode; a package can containing the battery element and being electrically connected to one of the cathode and the anode; and external connection terminal being connected to the other one of the cathode and the anode; and having a plate-like base contained in the package can and a leading portion extending to outside of the package can; and an insulating member separating the external connection terminal from the battery element. The base of the external connection terminal is spaced from an internal wall face of the package can, and the insulating member has notches at a position where the base of the external connection terminal is layered on the insulating member in the thickness direction of the package can.

Abstract: A battery with improved safety which can establish a short circuit between electrodes more reliably when the battery is crushed by an external force is provided. A battery includes a battery element including a cathode and an anode, a battery can containing the battery element, and a conductive short circuit member arranged in a gap between the battery element and the battery can, the short circuit member capable of biting into the battery element when the battery can is deformed.

Abstract: A battery includes: a battery element having a cathode and an anode; a package can containing the battery element and being electrically connected to one of the cathode and the anode; and external connection terminal being connected to the other one of the cathode and the anode; and having a plate-like base contained in the package can and a leading portion extending to outside of the package can; and an insulating member separating the external connection terminal from the battery element. The base of the external connection terminal is spaced from an internal wall face of the package can, and the insulating member has notches at a position where the base of the external connection terminal is layered on the insulating member in the thickness direction of the package can.

Abstract: A battery with improved safety which can establish a short circuit between electrodes more reliably when the battery is crushed by an external force is provided. A battery includes a battery element including a cathode and an anode, a battery can containing the battery element, and a conductive short circuit member arranged in a gap between the battery element and the battery can, the short circuit member capable of biting into the battery element when the battery can is deformed.