Battery shell with good sealing performance and cylindrical lithium battery

The utility model provides a battery case with good sealing performance and a cylindrical lithium battery, the battery case comprises a case body, the case body is a hollow structure with an opening at the upper end, a plugging assembly is arranged at the opening at the upper end of the case body, an electrode assembly and the case body are hermetically connected by the plugging assembly, a plurality of pressure relief ports are arranged on the plugging assembly, and sealing assemblies are arranged in the pressure relief ports. The plugging assembly comprises a plugging plate, a second pressure relief opening is formed in one side of the plugging plate in a penetrating mode, the side end of the plugging plate is made of a rubber material, and the plugging plate is connected with an opening in the upper end of the shell in any one of an extrusion forming mode and a detachable connecting mode; the technical problems that under the normal condition of an existing battery, a shell opening is packaged through lase