Primus Power

Primus Power is a California-headquartered stationary battery energy storage company. They are shipping a long duration zinc bromine flow battery, called the EnergyPod. Since their founding in 2009 Primus has received over $100M in equity capital from international venture capital and strategic investors, and over $30M in government grants from the US Department of Energy, Advanced Research Projects Agency-Energy, and the California Energy Commission.
EnergyPods are modular batteries for commercial, industrial, microgrid and utility customers. The low maintenance systems provide five hour of discharge energy and are rated for a twenty-year life span, necessary for grid applications. Primus has numerous customers including Microsoft, Puget Sound Energy, Miramar Marine Corps Airstation, HCP, Goldwind, Israel Chemicals and Victor Valley Wastewater Reclamation Authority.
The EnergyPod achieves a low capital cost by design: 1) an inexpensive zinc bromine electrolyte, 2) a single electrolyte tank (most flow batteries have two), and 3) absence of an ion exchange membrane (also called a separator) between electrodes. This design also leads to low maintenance cost.
Columbia University and Primus are jointly developing the EnergyCube, 10 kW - 100 kWh zinc bromine battery for residential and small commercial applications. This project is funded by ARPA-E.
Primus Power's batteries decouple instantaneous electricity demand from supply which helps integrate intermittent solar and wind renewable energy, and bolsters the stability and security of the electric grid. The company has been granted over thirty patents in chemistry, cell design, and system engineering, granted by more than six countries.