Battery charging and discharging device and rechargeable power supply

A battery charging and discharging device, comprising:

• a power conversion unit, configured to convert AC power into DC power and convert DC power into AC or DC power;
• a connecting end for an energy storage battery pack, configured to connect the energy storage battery pack;
• a connecting end for charging and discharging, configured to connect a charging power supply or a device to be charged or a load;
• a charging switch, comprising a first charging switch and a second charging switch, wherein the first charging switch is arranged in a connection line between the connecting end for charging and discharging and an input of the power conversion unit, and the second charging switch is arranged in a connection line between an output of the power conversion unit and the connecting end for the energy storage battery pack, wherein the connected power storage battery pack may be charged when the first charging switch and the second charging switch are closed;
• and
• a discharging switch, comprising a first discharging switch and a second discharging switch, wherein the first discharging switch is arranged in a connection line between the connecting end for the energy storage battery pack and the input of the power conversion unit, and the second discharging switch is arranged in a connection line between the output of the power conversion unit and the connecting end for charging and discharging, wherein the connected power storage battery pack may be discharged when the first discharging switch and the second discharging switch are closed.