Battery cell, manufacturing method and manufacturing system thereof, battery, and powered device

A battery cell, comprising:

• a shell, wherein the shell has a wall portion;
• an electrode assembly, wherein the electrode assembly is accommodated in the shell;
• and
• a pressure relief mechanism, wherein the pressure relief mechanism is provided on the wall portion, the pressure relief mechanism comprises a weak portion, a body portion, and a connecting portion, wherein the weak portion is configured to be damaged when pressure inside the shell reaches a threshold so as to relieve the pressure, the body portion is located in a region defined by the weak portion, and the connecting portion is located on an outer side of the weak portion and configured to connect the wall portion;
• and,
• wherein the body portion protrudes relative to the connecting portion in a direction away from the electrode assembly, and a first concave portion is formed in the pressure relief mechanism at a position corresponding to the body portion on a side facing the electrode assembly.