Provided are an end cover assembly, a battery, an electric device, a battery cell, and a manufacturing method thereof, pertaining to the technical field of batteries. The end cover assembly includes an end cover, a first electrode terminal, a second electrode terminal, a connecting member, and a pressure relief mechanism. The first electrode terminal is installed on the end cover; and the second electrode terminal is installed on the end cover. The connecting member is configured to be connected to the first electrode terminal and the second electrode terminal, where the connecting member is on a side of the end cover farther away from inside of the battery cell in a first direction. The pressure relief mechanism is disposed on the end cover, the pressure relief mechanism is at least partially located between the first electrode terminal and the second electrode terminal.