International Battery, which makes large-format lithium ion batteries for utility-grade energy storage, has raised $35 million in a series C round of funding.
The money comes from existing investor, private equity firm Digital Power Capital, and will be used for expanding manufacturing in Allentown, Penn., according to International Battery.
Many lithium ion battery companies, including A123 Systems and EnerDel, are developing packs for both vehicles and utility-grade storage.
International Battery's technology of large-format lithium ion cells is best suited for stationary uses, such as back-up storage for renewable energy. Its prismatic-shaped cells are about the size of bricks, rather than small cylinders used in many lithium ion batteries.
The large format allows the batteries to hold a lot of energy per volume, compared with others, according to the company. Its batteries are being tested in a microgrid, where a refrigerator-size storage unit will provide energy to a neighborhood, with Ohio utility AEP.
International Battery also uses a water-based process to manufacture the cells, rather than solvents, which can be environmentally harmful.