Battery cell, battery, electrical device, method and equipment for manufacturing battery cells

A method for manufacturing battery cells, comprising:

• providing an end cap and a casing body, the casing body having an opening, the end cap configured to seal the opening, either the casing body or the end cap being provided with a pressure-relief mechanism, the pressure-relief mechanism comprising a weak portion and a first portion and a second portion disposed on two sides of the weak portion, the weak portion being configured to connect the first portion and the second portion, and the pressure-relief mechanism being configured to cause the weak portion to be broken to release pressure when the pressure in a unit formed by the casing body and the end cap reaches a threshold value;
• providing a protective part arranged at the pressure-relief mechanism, the protective part being configured to connect the first portion and the second portion to increase strength of connection between the first portion and the second portion;
• providing an electrode assembly, installing the electrode assembly in the casing body;
• and
• assembling the end cap and the casing body, attaching the end cap to the casing body and covering the opening,
• wherein the weak portion is formed by forming a groove on an outer surface of the pressure-relief mechanism, at least a part of the protective part is accommodated in the groove, the protective part is configured to connect groove walls of the groove.