A flow battery can be recharged quickly by replacing its electrolyte liquid. Previous versions of liquid batteries, however, have relied on complex systems of tanks, valves, and pumps, adding to the cost and providing multiple opportunities for possible leaks and failures. A new liquid battery created by Massachusetts Institute of Technology researchers, substitutes a simple gravity feed for the pump system.

A new concept for a flow battery functions like an old hourglass or egg timer, with particles (in this case carried as a slurry) flowing through a narrow opening from one tank to another. The flow can then be reversed by turning the device over.
Credits:Image courtesy of the researchers.

The gravity-feed system functions like an old hourglass or egg timer, with particles flowing through a narrow opening from one tank to another. The flow can then be reversed by turning the device over.

In the team's proof-of-concept version, only one of the two sides of the battery is composed of flowing liquid, while the other side — a sheet of lithium — has a solid form.

The new design possibly enables simpler and more compact battery systems; the inexpensive and modular batteries allow for gradual expansion of grid-connected storage systems.

Source 

Also: Learn about NASA's High-Energy-Density Solid-State Li-Ion Battery .