Los Angeles-based Nanotech Energy, a developer of graphene-based battery technology, says it has raised $64M in a Series D funding round. The company said the funding was led by Fubon Financial Holding Co., Taiwan's largest financial services company. The company said the latest round gave it a $550M post-Series D valuation, and brings its total raised to $94.9M. Nanotech Energy said the new funds will go towards international expansion, including the launch of its EU headquarters in Amsterdam, and to develop a new high-volume graphene battery manufacturing facility in Reno, Nevada. The company currently has a factory in Chico. The company's technology is based on research of co-founder and UCLA professor of Chemistry and of Materials Science and Engineering, Dr. Richard Kaner.