By Nick Carey

LONDON (Reuters) -Battery materials startup GDI said on Tuesday it has raised an additional $11.5 million in Series A funding to scale up production of silicon anodes for electric vehicle batteries in the United States and Europe.

The Rochester, New York-based company said the additional funding was led by Helios Climate Ventures, Impact NY, and InnoEnergy and brings its total Series A raise to over $20 million.

GDI says its anodes provide 30% more energy density than conventional graphite anodes and charge times of under 15 minutes for EVs.

CEO Rob Anstey said the funding will help the company scale up production at its pilot plant in the Netherlands within the next 24 months to start providing anodes to battery manufacturers.

Anstey said GDI has already signed a joint-development agreement with an EV cell manufacturer, which should mean its anodes will be in battery cells in drones and medical devices within the next 24 to 30 months and in EVs on the road by 2030.

He declined to say which cell manufacturer GDI has signed a contract with.

"Normally it takes about five years" to get into an EV program with an automaker," Antsey said. "We do believe we can be in the next generation of EVs and have a design win by 2030."

The company is one of a number of startups developing silicon anodes, including Nexeon, Group14 Technologies and Sila Nanotechnologies, all touting better performance than graphite.

China refines more than 90% of the world's graphite into the material used in almost all EV battery anodes.

Last year the European Investment Bank provided 20 million euros ($22.5 million) in loans and equity to GDI to scale up production and the additional funding is intended to match part of that loan facility.

($1 = 0.8894 euros)

(Reporting By Nick Carey, editing by David Evans)