Liquid nitrogen tank with full-size top cover capable of being automatically opened and closed

The utility model provides a liquid nitrogen tank with a full-size top cover capable of being automatically opened and closed. The liquid nitrogen tank comprises a tank body, a taking and placing opening is formed in the upper end of the tank body, and one side of the tank body is connected with a connecting frame through a mounting plate; one end of the connecting frame is connected with a top cover, and the top cover is in close contact with the pick-and-place opening; the connecting frame is connected with a ball bearing through a rotating shaft, and the ball bearing is connected with the mounting plate; one end of the rotating shaft is connected with a motor; and the motor is connected with the tank body through a supporting seat. The top cover is driven by the motor to rotate at the top of the tank body, so that the top cover is automatically opened and closed on the liquid nitrogen tank body, and the liquid nitrogen tank is more convenient to open and close; a full-size pick-and-place opening design is