Sustainable Energy

Building Cheap Batteries to Circumvent the Grid

Startup Aquion prepares to ramp up production of products for storing power in remote microgrids.

Sep 10, 2012

Photographs by Kevin Bullis | Technology Review

To reduce costs, Aquion has decided to do all of its materials processing in-house. One of the first steps is running raw materials—activated carbon and manganese oxide—through a calciner, shown here, which treats them at high temperatures.  
This finished manganese oxide cathode electrode is ready to be incorporated into a battery cell. Aquion’s sodium-ion batteries operate similarly to lithium-ion batteries, but they use far thicker electrodes that are cheaper to make and allow for simpler battery cells. The thicker electrodes are enabled by the use of a water-based electrolyte that’s more conductive than the organic solvent electrolyte that lithium-ion batteries use. (Aquion gets its name by combining aqua with ion.)
This machine uses small suction cups to pick up electrode wafers and place them into the battery case. It’s the same kind of equipment used in candy factories.
Aquion founder Jay Whitacre shows off one of the completed battery cells. Each cell contains multiple layers of electrodes. 
Several stacks of cells will be put together into a complete battery pack like the one shown here. Whitacre points to electrical connections that allow the packs to be plugged into one another “like Legos” to form large arrays.
Battery cells are stacked up and pressed together by steel plates at each end to ensure good connections within the pack. Here an array of cells is charged and discharged as a performance test.
Aquion is testing several such systems with its batteries in the backyard of its headquarters. Whitacre calls the small one on the ground a “solar generator” because it’s meant to replace conventional generators as a small source of backup power. It’s hooked up to a small, efficient refrigerator inside the shed.
The new factory will eventually occupy up to about 500,000 square feet of a former Sony television factory. Construction workers (seen zooming by on a golf cart) are just starting to build laboratory spaces, the walls of which can be seen in the background.  

Microgrids, which typically combine renewable energy, batteries, and conventional diesel generators to provide electricity around the clock, are bringing power to remote villages around the world that don’t have access to the conventional grid. But they’re limited by the high cost and short lifetimes of batteries. Aquion, a startup based in Pittsburgh, is developing a battery that could be just as cheap as lead-acid batteries—the cheapest available now—but last two or three times as long, greatly lowering the lifetime cost of microgrids.

Aquion is building test versions of its batteries at a small pilot-scale factory. It will start shipping these batteries—which will be essentially the same as the final version of the battery—to customers next month. Technology Review got a look inside the factory to see how the new batteries are made. (For Technology Review’s initial coverage of Aquion, and more detail about the technology, see “Battery to Take on Diesel and Natural Gas.”)