We were just fooling around with the notion that new fuel cell technology could shake up the electric vehicle market, when here comes GE with another alternative: a flow battery that combines with a fuel cell to push EV range up to the Department of Energy’s goal of 240 miles, and even farther. The official rated range of Tesla Motors’ highly regarded but highly costly Model S is already 265 miles on a lithium-ion battery pack, so the big factor here is going to be affordability. With that in mind let’s take a look at that GE flow battery and see what’s doing.
The New GE Flow Battery
A typical flow battery consists of two separate liquids flowing on either side of a membrane. Like fuel cells, EV flow batteries would generate electricity on board the vehicle through an electrochemical reaction, rather than drawing electricity from the grid and storing it.
Water-based flow battery system courtesy of GE Global Research.
The challenge has been to lower the cost of the main components, including the liquids and the membrane. Another big challenge is to achieve an energy density level that enables the whole battery system to shrink down to a size and weight workable for passenger vehicles.
GE’s flow battery technology is water-based, but before you get all excited about filling up your gas tank with water bear with us for a second. By water-based they simply mean a water-based solution of inorganic chemicals.
Here’s how it would work, keeping in mind that the idea is to combine the “best properties” of both flow batteries and fuel cells:
A hydrogenated organic liquid carrier is fed to the anode of a PEM fuel cell where it is electrochemically dehydrogenated, generating electricity, while air oxygen is reduced at the cathode to water. To recharge the flow battery, the reactions are reversed and the organic liquid is electrochemically re-hydrogenated, or rapidly replaced with the hydrogenated form at a refueling station.
The result, in theory, is an energy density of up to 1350 Wh/kg, which according to GE would be a record-setter for secondary batteries.
More to the point, the GE research team anticipates that their flow battery system could be produced for 75 percent less than the cost of a typical lithium-ion battery pack, which right now is the gold standard for EV batteries.
However, if you really want to go ahead and buy an EV now, don’t wait on GE. Between lower operating costs, subsidies, and a downward trend in battery prices, the cost of a good EV has already dropped to the affordability range for many car buyers. You can always trade it in a few years down the line, whenever GE’s new flow battery hits the market.
According to GE Global Research, which is heading up the project, the next step is to translate the labwork into a working prototype and demonstrate the feasibility of the technology, so commercialization is still a long way off.
We Built This New GE Flow Battery!
GE is not shy about crediting its research partners, so why should we be? GE Global Research has been recognized by the Obama Administration as an Energy Frontier Research Center funded by the Department of Energy, charged with developing game-changing energy storage technologies. According to GE, it is the only corporate research center chosen for such a role.
The project itself comes under the Energy Department’s ARPA-E RANGE initiative, which has the goal of making EV ownership just as affordable and convenient as owning a gasoline vehicle.
Other partners include Yale University– Crabtree Group, Yale University– Batista Group, Stanford University, and Lawrence Berkeley National Laboratory.
All Roads Lead To Cheaper Flow Batteries
Aside from GE’s approach, other research teams are addressing the membrane cost issue by doing away with it altogether. At MIT, for example, they’re working on a bromine based flow battery with no membrane.
Electric vehicles represent just one market for flow batteries, by the way. Another major market is grid-scale energy storage, and we taxpayers have been hard at work on that one, too.
One good example is Pacific Northwest National Laboratory, which has partnered with the company UniEnergy to develop a grid-scale flow battery based on two different vanadium ions (vanadium is a soft metal).
Another example comes from Sandia National Laboratories, which is using a solution of liquid salts called MetiLs in its low cost flow battery project.