Celgard, LLC

Its solvent-free process extrudes, laminates, anneals and stretches polypropylene and other films into base films, and the company adds functional coatings on top. The same membranes go into waterproof breathable apparel and medical protective equipment. Its battery labs include dry rooms with automated cell assembly for testing separators with customers' electrode and electrolyte materials.

Celgard is headquartered in Charlotte, North Carolina, with plants in Charlotte, Concord and Shanghai, China, and is a wholly owned subsidiary of the Asahi Kasei Group. It was established more than 50 years ago.