Researchers at MIT have published a new flow-battery design which provides a 10-fold improvement in energy density over previous models. It is expected to help increase the energy storage capacity of wind or solar power plants and could reduce the time it takes to recharge electric vehicle batteries:
A radically new approach to the design of batteries, developed by researchers at MIT, could provide a lightweight and inexpensive alternative to existing batteries for electric vehicles and the power grid. The technology could even make “refueling” such batteries as quick and easy as pumping gas into a conventional car.
The new battery relies on an innovative architecture called a semi-solid flow cell, in which solid particles are suspended in a carrier liquid and pumped through the system. In this design, the battery’s active components — the positive and negative electrodes, or cathodes and anodes — are composed of particles suspended in a liquid electrolyte. These two different suspensions are pumped through systems separated by a filter, such as a thin porous membrane.
The work was carried out by Mihai Duduta ’10 and graduate student Bryan Ho, under the leadership of professors of materials science W. Craig Carter and Yet-Ming Chiang. It is described in a paper published May 20 in the journal Advanced Energy Materials.
A project to develop a grid-scale pilot plant using flow-batteries was seeded with funding from the Department of Energy. Private investors have kicked in an additional $11 million to create a test installation in Modesto, California:
Flow batteries are soon going to be implemented for grid-scale power storage in the US. A test instalation in Modesto, California is being built to provide 25 MW of power for up to 3 hours as well as serving as a demonstration of grid-tied flow battery storage. The Modesto area has wind-energy resources which will serve as the energy source which charges the system.
Flow batteries use large tanks of electrolyte chemicals for a large energy storage capacity, but only a small amount of the chemicals are in contact with the reactive electrodes. This allows large capacity at fairly low cost, since much of the hardware is fairly basic chemical storage tanks and pipes. A more complex kind of flow batteries for electric vehicle charging was also recently noted on EcoGeek.
Primus Power, the company which has developed this technology, received a $2 million award from the US Department of Energy's ARPA-E program last year, and has raised another $11 million in private investment. The company's technology is in the development of low-cost and durable electrodes that will allow flow batteries to function for a long time.
How a flow battery works: the active materials--the anode and cathode--are in a liquid form and flow past a membrane to create the chemical reactions to charge and discharge a battery.
(Credit: Advanced Energy Materials)