Do flow batteries still need to be charged

A flow battery can be recharged in two ways: The two solutions can be charged in place by a current moving in the opposite direction, or the spent solutions can be replaced with charged ones.

Battery geeks refer to the latter feature as a shallow “depth of discharge”. Flow batteries are a new entrant into the battery storage market, aimed at large-scale energy storage applications. This storage technology has been in research and development for several decades, though is now starting to gain some real-world use.

The new flow battery seems to hit every mark. If it works, the benefits to the electrification of transportation would be huge. Nanoelectrofuel batteries are a new take on the reduction-oxidation (redox) flow battery, which was first proposed nearly a century and a half ago.

Flow batteries can discharge up to 10 hours at a stretch, whereas most other commercial battery types are designed to discharge for one or two hours at a time. The role of flow batteries in utility applications is foreseen mostly as a buffer between the available energy from the electric grid and difficult-to-predict electricity demands.

The energy storage capacity of a flow battery can be easily increased by adding larger tanks to store more electrolyte. This is a key advantage over solid-state batteries, like lithium-ion, where scaling up often requires more complex and expensive modifications.

The main difference between flow batteries and other rechargeable battery types is that the aqueous electrolyte solution usually found in other batteries is not stored in the cells around the positive electrode and negative electrode. Instead, the active materials are stored in exterior tanks and pumped toward a flow cell membrane and power stack.