The Chinese city of Dalian already has the first 400 MWh of the energy storage plant from renewable sources connected to its electricity grid. This stationary battery is flow and has been manufactured by Rongke Power.
In recent years, flow batteries have been gaining market presence after overcoming the research and development phase in laboratories.
Broadly speaking, redox flow batteries consist of two compartments with liquid electrolytes, one with a positive charge and the other with a negative charge. In order to separate both electrodes, a membranethrough which a transition occurs that causes a reversible electrochemical reaction with which to store and generate electricity.
VPower, a vanadium redox flow battery
The new large battery of Rongke Power uses this technology, betting on vanadium as a metal for the production of electrolytes.
Although this electrochemical combination offers a much lower energy density than lithium ions, it is capable of reaching a very high capacity and it has a long useful life thanks to its stability of charge and discharge cycles.
All this makes vanadium redox flow batteries ideal for large energy storage facilities, such as the one recently opened in the Chinese city of Dalian.
There is installed a capacity of 400 MWh and 100 MW of power in a first phase, although the plan is to double these figures. This makes Rongke’s VPower already the world’s largest battery in its category, surpassing Sumitomo Electrics’ 17MW/51MWh.
Technical characteristics
VPower is a product in which the power section adopts a standardized design and the capacity section adopts a customized design to meet customers’ requirements for different durations of energy storage.
The standard battery module, with a rated power 250kWconsists of a 6 meter container with power cells, two external electrolyte tanks, BMS, piping system, etc.
Depending on the design of the external tanks, the amount of electrolyte can be configured on request to achieve capacity customization. By connecting the two battery modules in series to a PCS, a 500kW unit can be formed.
Also it is possible to connect several groups of units to the bus in parallel to build a larger-scale energy storage system. Taking the 10MW/40MWh battery system as an example, based on single-layer deployment, it covers a space of about 3850 square meters. With a dual-layer deployment, that space would be around 2,250 square meters, including maintenance space.
Font: Rongke Power
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Photos: Rongke Power