The utility model relates to the technical field of secondary batteries, in particular to a secondary battery and a
battery pack. The battery comprises a shell, a top cover, a
battery cell and a connecting piece, the
battery cell is contained in a containing cavity defined by the shell and the top cover, the connecting piece comprises a tab connecting part connected with a tab of the
battery cell in a welded mode and a pole connecting part connected with a pole on the top cover in a welded mode, and the tab connecting part and the pole connecting part are connected through a transition part. And the distance F between the first surface, facing the battery
cell, of the tab connecting part and the second surface, facing the battery
cell, of the pole connecting part is greater than 0 and less than or equal to 0.5 mm after the tab connecting part is shifted. Therefore, the
potential difference formed by the pole connecting part and the tab connecting part on one side facing the top cover is utilized to avoid the part, extending towards the battery
cell, of the pole on the top cover, the bent tab height of the battery cell is fully utilized under the condition of ensuring normal
assembly of the secondary battery, the space
utilization rate in the secondary battery is improved, and the
energy density of the secondary battery is improved.