Eos Energy raises $15M from NRG, investors for zinc-air batteries

Startup Eos Energy Storgae announced on Monday that it has raised a $15 million series B round from a group of investors including power company NRG Energy. Eos Energy, based in New Jersey, has been building a low cost grid battery using air and zinc that it hopes utilities and power companies will buy to help manage their grids and combine with solar and wind projects.

The company is looking to use the funding to help commercialize its batteries, which they’re calling Aurora, and Eos Energy hopes to deliver those to the market in 2014. According to a filing, this B round has been under development for over a year, and the company also says in its release that it is already in the process of raising a series C round, too.

Eos Energy is testing out its first batteries with New York utility ConEdison, and the two are using a state grant to install batteries on the New York grid. The company says it also has other utility partners in the works.

Scientists have been working on using air as the cathode for batteries for half a century. A battery is made up of an anode on one side and a cathode on the other, with an electrolyte in between. Air, of course, is abundant, light weight, and doesn’t require a heavy casing to contain it inside a battery cell. Also theoretically air can achieve a high energy density, or amount of energy that it can store.

Eos Energy tech innovation comes from founder and inventor Steven Amendola who discovered a breakthrough with his original design of the bi-directional air cathode that could last for 10,000 cycles (or around three decades). The company has told me that its initial battery could cost $160 per kWh, lasts 30 years and be made up of everyday benign materials.