The energy storage technology of Fe-Cr flow battery is known as one of the longest and safest electrochemical energy storage technologies. The electrolyte of this technology is an aqueous solution, which will not explode, and the power and capacity can be flexibly customized according to the needs. It has the advantages of long cycle life, good stability, easy recovery, wide working temperature range and low cost, and meets the needs of large-scale and long-term energy storage in China.