End cover assembly, battery monomer, battery and electric equipment

The embodiment of the invention provides an end cover assembly, a battery monomer, a battery and electric equipment, and relates to the technical field of batteries. An end cap assembly for a battery cell includes an end cap, an insulator, and a switch member. The end cover is used for closing the first opening of the shell of the battery cell; the insulating part is arranged on the side, facing the shell, of the end cover, a containing cavity is formed in the insulating part, the containing cavity is used for containing a flame-retardant medium, and the insulating part is provided with a discharging opening communicated with the containing cavity. The switch part is connected to the insulating part and seals the discharge port, and the switch part is configured to open the discharge port when the battery monomers are in thermal runaway so as to release the flame-retardant medium into the shell. And when the single battery has a trend of thermal runaway, the switch component opens the discharge port of the accommodating cavity, so that the flame-retardant medium is injected into the shell, the combustion reaction in the shell is inhibited, and the safety of the single battery is improved.