Cylindrical lithium-ion battery

Abstract

A cylindrical lithium-ion battery comprising a negative cap (1), a cylindrical housing (2), a coiled electrode (4), a negative current collector (3), a positive pole (5), an insulating sealing member (7), and a positive current collector (6), characterized in that the coiled electrode (4) and the negative current collector are disposed inside the housing (2), an annular inwardly concave groove (21) is provided on the side of the bottom of the housing (2); the annular inwardly concave groove (21) is arranged circumferentially around the axis of the housing (2); and the annular inwardly concave groove (21) forms an annular protrusion inside the housing (2); the negative current collector (3) is connected to the negative coiled electrode (4), the part of the housing (2) below the annular inwardly concave groove (21) is bent to form an annular fitting groove (22); the opening of the annular fitting groove (22) faces the inside of the housing (2);the circumference of the negative cap (1) is arranged in the annular fitting groove (22), and the lower surface of the negative cap (1) and the annular fitting groove (22) are sealed together by laser welding;