Direct-current power supply automatic switching device and system

The invention discloses a direct-current power supply automatic switching device and system. The device comprises a first power supply monitoring module, a control module, a first driving module and afirst direct-current air switch. The first power supply monitoring module monitors a first working voltage of a first direct current source, and the first direct current source supplies power to external equipment; the first input end of the control module is electrically connected with the output end of the first power supply monitoring module; the input end of the first driving module is electrically connected with the first output end of the control module, and the driving end of the first driving module is electrically connected with the first direct-current air switch; the first end of the first direct-current air switch is electrically connected with a second direct-current source, and the second end of the first direct-current air switch is electrically connected with external equipment; the control module