| Work Detail |
Researchers at Chinas Dalian Institute of Chemical Physics (DICP) have developed a 70 kW vanadium flux cell. Thanks to its volumetric power density of 130 kW/m3, the newly designed battery is 40% cheaper than current 30 kW batteries.
Vanadium flow batteries are one of the most promising technologies for large-scale energy storage, due to their long cycle life, excellent recyclability and low fire risk. However, its adoption is very limited due to its low energy densities compared to lithium-ion technology, as well as its high initial cost.
Now, a team of researchers from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences has developed a vanadium flux cell with high energy density and 70 kW of power. Compared to the current 30 kW battery, the new one is 40% cheaper.
With a higher power density of 130 kW/m3, the new cell has a smaller volume, which translates into a lower cost under the same power conditions. With this stack, an energy storage unit in a 20-foot container can go from 250 kW to 500 kW without greatly increasing the size of the power units or the cost of system support facilities.
The research team designed the new stack based on self-developed highly selective weldable porous composite membranes and highly conductive weldable bipolar plates. It also used a short flow path, ultra-thin stack structure, and flow channels of low flow resistance and high distribution uniformity.
The energy efficiency of the cell is 81% under charge and discharge conditions at a nominal power of 70 kW, and 82.1% under charge and discharge conditions at a constant power of 60 kW. Furthermore, the battery operates stably after more than 1,200 cycles, with a decrease in energy efficiency of only 1.7%, the researchers reported.
“This 70 kW cell can boost the commercialization of vanadium flow batteries. We believe that the development of this stack will improve the integration of power units in energy,” said Professor LI Xianfeng, head of the research team.
With a lifespan of more than 20,000 cycles, redox flow batteries can offer a lower levelized cost of storage (LCOS) than lithium-ion batteries. However, the CAPEX per kWh of the most widespread type of flow chemistry, vanadium redox flow batteries, is higher.
Since lithium-ion batteries are less suitable for storing energy for more than six hours, redox flow batteries offer a cheaper alternative for longer storage periods, thanks to their decoupled scaling of power and energy. Specifically, increasing the storage life of redox flow batteries only requires scaling the electrolyte storage tanks and electrolyte volumes, while the cell stack configurations can remain unchanged. |
