Battery and battery pack

The invention relates to the technical field of batteries, in particular to a battery and a battery pack. The battery provided by the invention comprises a shell, a positive end cover, a negative end cover and a plurality of roll cores, the shell is tubular, the shell is provided with a containing cavity extending in the axial direction of the shell, a first opening and a second opening, the first opening and the second opening are located at the two ends of the shell, and the roll cores are arranged in the containing cavity; the positive electrode end cover covers the first opening, the negative electrode end cover covers the second opening, and the two ends of each roll core are connected with the positive electrode end cover and the negative electrode end cover respectively. According to the battery provided by the embodiment of the invention, the plurality of roll cores are arranged in the shell, and the plurality of roll cores are respectively connected with the positive end cover and the negative end co