Though considered a promising large-scale energy-storage device, the vanadium redox battery’s use has been limited by its high cost and its sensitivity to extreme temperatures. However, new research may have discovered how to improve its performance to the point that the upgraded battery could improve the electric grid’s reliability and help store electricity, making wind turbines and solar panels more viable.
The Department of Energy’s Pacific Northwest National Laboratory (PNNL) announced a new method that would increase vanadium batteries’ energy--storage capacity by 70 percent and expand the temperature range in which they operate.
Unlike traditional power, which is generated in a reliable, consistent stream of electricity, renewable-power production depends on uncontrollable natural phenomena, such as sunshine and wind. Storing electricity can help smooth out the intermittence of renewable power while also improving the reliability of the electric grid that transmits it.
“Our small adjustments greatly improve the vanadium redox battery,” said Liyu Li, lead author and PNNL chemist. “And with just a little more work, the battery could potentially increase the use of wind, solar and other renewable-power sources across the electric grid.”
One large drawback for current vanadium batteries is that they only work between approximately 50–104°F (10–40°C). Below that temperature range, their ion-infused sulfuric acid crystallizes. The larger concern, however, is the battery overheating, which causes an unwanted solid to form and renders the battery useless. Air conditioners or systems that circulate cooling water can help regulate the temperature, but they can cause up to 20 percent energy loss and significantly increases operating costs.
To improve the battery’s performance, Li and his colleagues found a new electrolyte mixture that can hold 70 percent more vanadium ions. The discovery means the batteries can be smaller while generating the same amount of power.
The new mixture also allows the batteries to work in both warmer and colder temperatures, between 23–122°F (–5–50°C), greatly reducing the need for costly cooling systems.
The results are promising, but more research is needed, the authors noted. The battery’s stack and overall physical structure could be improved to increase power generation and decrease cost.
“Vanadium redox batteries have been around for more than 20 years, but their use has been limited by a relatively narrow temperature range,” Li said. “Something as simple as adjusting the batteries’ electrolyte means they can be used in more places without having to divert power output to regulate heat.”