A new type of vanadium flow battery stack has been developed by a team of Chinese scientists, which could revolutionize the field of large-scale energy storage.

Vanadium flow batteries are a promising technology for storing renewable energy, as they have long lifespans, high safety, and scalability. However, they also have a high initial cost, which limits their widespread adoption.

The key component of a vanadium flow battery is the stack, which consists of a series of cells that convert chemical energy into electrical energy. The cost of the stack is largely determined by its power density, which is the ratio of power output to stack volume. The higher the power density, the smaller and cheaper the stack.

To achieve a high power density, the researchers from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) designed a 70 kW-level stack, which is more than twice as powerful as the current 30 kW-level stack. They used self-developed materials, such as weldable porous composite membranes and weldable highly conductive bipolar plates, to create a stack with a short flow path, an ultra-thin battery structure, low flow resistance, and high distribution uniformity flow channels.

The result is a stack with a volume power density of 130 kW/m3, and a cost reduction of 40%. The stack also has a high energy efficiency of over 80% under different power conditions, and a stable performance after more than 1,200 cycles, with only 1.7% energy efficiency decay.

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