Housing, battery cell, battery and electric apparatus

A method for manufacturing a case, comprising:

• providing a case body, the case body being used for accommodating an electrode assembly;
• and
• obtaining a pressure relief structure on the case body to form a plurality of first pressure relief grooves disposed at intervals on the case body along the circumferential direction of the case body;
• wherein the case body is configured to rupture along the first pressure relief groove when the pressure or temperature inside the case body reaches a threshold, so as to release the pressure inside the case body.

A manufacturing apparatus for a case, the manufacturing apparatus including:

• a providing device for providing a case body, the case body being used for accommodating an electrode assembly;
• and
• a processing device for processing to obtain a pressure relief structure on the case body, so as to form a plurality of first pressure relief grooves disposed at intervals on the case body along the circumferential direction of the case body;
• wherein the case body is configured to rupture along the first pressure relief groove when the pressure or temperature inside the case body reaches a threshold, so as to release the pressure inside the case body.