The application relates to an end cover assembly, a battery cell, a battery, and a device and method for manufacturing a battery cell. The end cover assembly is used for a battery cell, and includes a cover plate, the cover plate is provided with a pressure relief hole penetrating through the cover plate in a thickness direction, a breathable film, arranged opposite to the pressure relief hole and configured to exhaust gas inside the battery cell, a projection of the breathable film in the thickness direction does not overlap with a projection of the cover plate in the thickness direction; and a fixing member, configured to connect the cover plate to fix the breathable film. The application intends to solve the problem of a large space occupied by the breathable film.