Cover assembly, battery cell, battery, electric device, method and apparatus

A cover assembly of a battery cell, comprising:

• a cover plate provided with a first through hole, the first through hole comprising an accommodation section and an extension section extending from the accommodation section, and a diameter of the accommodation section being greater than a diameter of the extension section;
• a fixing member connected to the cover plate and provided with a second through hole, wherein the second through hole is configured to be in gas communication with the first through hole;
• a breathable film connected to the fixing member, wherein the breathable film is used for covering the second through hole;
• and
• a support filled in the second through hole, connected to the fixing member, and used for supporting the breathable film and allowing gas to pass through the breathable film, wherein the fixing member and the support are at least partially accommodated in the accommodation section;
• wherein the accommodation section is provided with a bottom wall surrounding the extension section, the breathable film is at least partially sandwiched between the fixing member and the bottom wall to separate the second through hole from the extension section, and the support is arranged on one side, away from the extension section, of the breathable film.