Power grid energy storage system

The invention discloses a power grid energy storage system. The system comprises a plurality of battery modules, the battery modules comprise lithium batteries and DC/DC converters, all the DC/DC converters are connected to a direct current bus to form parallel connection, an autonomous current-sharing control module is connected between the DC/DC converters, a communication module, a droop control unit or other autonomous current-sharing control modules are connected between the DC/DC converters, the DC/DC converters can work in an autonomous current-sharing mode with/without the communication module, the autonomous current-sharing control module can also be connected with an intermediate computer, the ordered charging and discharging mode work of the lithium batteries is realized, and remote monitoring can be realized by employing a remote control terminal. The system is applicable to various current-sharing and charging and discharging work states, the dynamic performance is substantially enhanced, the sys