Large-capacity vanadium redox flow battery (VRFB) is a representative long-duration energy storage technology suitable for industrial and grid-scale scenarios, featuring capacity-power decoupling, ultra-long cycle life, and intrinsic safety, and has become a core solution for large-scale, long-time energy storage in the new energy era. Different from traditional lithium-ion batteries that integrate energy storage and power generation in a single cell, the vanadium flow battery adopts a unique structural design that separates the electrochemical reaction stack and the electrolyte storage tank . The system power is determined by the number and area of battery stacks, while the energy storage capacity depends entirely on the volume and concentration of vanadium electrolyte stored in external tanks. This innovative structure enables free expansion of energy storage capacity without changing power equipment, perfectly meeting the large-capacity energy storage demands of industrial parks, grid peak regulation, and new energy power stations .

In terms of working mechanism, the large-capacity vanadium flow battery relies on the reversible redox reaction of vanadium ions with different valence states in the electrolyte to realize electric energy storage and release. Driven by circulating pumps, the positive and negative vanadium electrolytes flow through the electrode surface of the reaction stack continuously. During charging, vanadium ions undergo oxidation-reduction reactions to convert electrical energy into chemical energy for storage; during discharging, the reverse reaction occurs to convert stored chemical energy back into electrical energy for external output . The all-vanadium electrolyte is a fully recyclable and non-degradable medium, with no cross-pollution between positive and negative electrolytes, eliminating the risk of battery capacity attenuation caused by electrolyte aging and failure. Large-capacity VRFB products usually support 8–12 hours of long-duration discharge, with a cycle life of more than 20,000 times, and can operate stably for more than 20 years, far exceeding the service life of traditional lithium batteries .

Large-capacity vanadium flow batteries have outstanding safety and environmental advantages, making them suitable for large-scale industrial and public energy storage scenarios with high safety requirements. The electrolyte is water-based, non-flammable, non-explosive, and will not generate high temperature or thermal runaway during operation, fundamentally avoiding major safety accidents such as fire and explosion common in chemical batteries . In terms of operational performance, the battery supports full-depth discharge without damage to the system, with stable voltage output and strong adaptability to harsh working environments such as high temperature, low temperature, and high humidity. At present, the world’s largest 200MW/800MWh vanadium flow battery energy storage project has been successfully put into operation, effectively reducing the abandonment rate of local new energy and improving grid operation stability . With the continuous maturity of technology and cost reduction, large-capacity vanadium flow batteries are widely used in factory centralized energy storage, grid peak shaving and frequency modulation, renewable energy consumption, and emergency power guarantee, becoming a key support for the construction of new power systems .