This new "flow battery" tech sounds great, but the posted link was a little short on details. I found a couple articles which give a bit more information.

An article I found from August gives a helpful diagram (below) and this interesting fact:

"One problem with flow batteries is that they're enormous. In order to power a house, you'd need a flow battery about half the size of your garage, Frankel said."

The article is here:
As energy push accelerates, battery costs set to plunge 60%
http://www.networkworld.com/article/2977783/data-center/as-energy-push-accelerates-battery-costs-set-to-plunge-60.html

Excerpt:

Flow batteries vs. Li-ion batteries

Flow batteries and Li-ion batteries work well with intermittent energy sources such as solar panels and wind turbines because of their ability to be idle for long periods without losing a charge. Flow batteries, however, scale more easily because all that's needed to grow capacity is more liquid; the hardware remains the same, according to Dean Frankel, an associate at Lux Research.

That means flow batteries have the potential to be less expensive than Li-ion. They also last longer, according to Frankel. At full discharge, Li-ion batteries last only four hours. To double that length of charge, another complete battery unit must be added, Frankel said.

Flow batteries get their name because they use liquid chemicals (electrolytes) that are separated by a membrane. The reaction between the two chemicals frees up electrons, creating electricity.


Creative Commons Lic.
The basic concept behind how a flow battery works.

One problem with flow batteries is that they're enormous. In order to power a house, you'd need a flow battery about half the size of your garage, Frankel said.

Li-ion batteries, like Tesla's, can hang on a garage wall.

In the end, the distributed energy market will probably use a range of different battery technologies, Frankel added.

Lux Research's figures for battery prices between now and 2024 differ from the ARENA report, but still anticipate price drops. For a flow battery system, the cost is currently $755/kWh for a 4-hour battery, according to Lux. That cost is expected to fall to $516/kWh by 2024. For large scale Li-ion systems, costs will fall from $626/kWh in this year to $498/kWh in 2025, according to Lux Research.

So on a per-kilowatt basis, flow batteries will almost always be more expensive. However, on a per-kilowatt-hour basis (i.e., how long they can run, depending on how large the electrolyte fluid tanks are) they can be cheaper. The larger the tanks, the more power you can get.

Another article I found is older, from 2011, but gives more details including using certain aspects of lithium-ion technology in the flow battery.

This article is here:

Wednesday, July 6, 2011
New Battery Architecture at MIT

Excerpt:

The key insight by Chiang's team was that it would be possible to combine the basic structure of aqueous-flow batteries with the proven chemistry of lithium-ion batteries by reducing the batteries' solid materials to tiny particles that could be carried in a liquid suspension - similar to the way quicksand can flow like a liquid even though it consists mostly of solid particles. "We're using two proven technologies, and putting them together," Carter says.

In addition to potential applications in vehicles, the new battery system could be scaled up to very large sizes at low cost. This would make it particularly well-suited for large-scale electricity storage for utilities, potentially making intermittent, unpredictable sources such as wind and solar energy practical for powering the electric grid.

The team set out to "reinvent the rechargeable battery," Chiang says. But the device they came up with is potentially a whole family of new battery systems, because it's a design architecture that "is not linked to any particular chemistry." Chiang and his colleagues are now exploring different chemical combinations that could be used within the semi-solid flow system. "We'll figure out what can be practically developed today," Chiang says, "but as better materials come along, we can adapt them to this architecture."