Power grid energy storage system

Abstract

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 system is also applicable to different conditions including different battery states of charge, different battery power levels, and single module faults etc. of a battery pack, acomplex energy scheduling policy is easy to realize, and the dynamic performance of the power grid energy storage system is enhanced.

Description

technical field [0001] The invention relates to the field of group application of power lithium-ion batteries and power energy storage, in particular to a power grid energy storage system suitable for multiple DC / DC converters. Background technique [0002] As an indispensable part of the use of new energy, battery energy storage also affects the development of new energy. With the continuous expansion of my country's power grid capacity, the increasing peak-to-valley difference, and the vigorous development of renewable energy, distributed energy supply and smart grid, the demand for large-scale development of battery energy storage technology is increasing. However, battery pack technology has become a technical bottleneck for the large-scale development of energy storage. [0003] The direct parallel use of multiple lithium batteries in different states will cause abnormal flow of power and cause damage to the battery. A DC / DC conversion device is connected in series wit...

AI Technical Summary

Problems solved by technology

Because lithium-ion batteries cannot be floated and balanced like lead-acid batteries, resulting in the higher the series voltage, the more serious the voltage inconsistency of lithium-ion battery cells in the battery pack, but the power grid that lithium-ion battery packs with voltage levels such as 48V and 60V can provide Energy storage capacity is very limited

According to relevant literature, there are few proposals for parallel connection of lithium batteries with multiple DC / DC converters at voltage levels of 48V and 60V.

Images