Dc power supply device

A DC power supply device, comprising:

• a DC power bus;
• a first detection circuit, coupled to the DC power bus and configured to detect an external power source entering the DC power bus;
• a second detection circuit, coupled to the DC power bus and configured to detect a load status at the DC power bus;
• a plurality of battery modules, each detachably assembled to the DC power bus;
• and
• a management circuit, communicating with the first detection circuit, the second detection circuit, and a plurality of assembled battery modules assembled to the DC power bus and configured to adjust a power supply quantity of the assembled battery modules based on the load status in response to the DC power bus not receiving the external power source.