Speaking ahead of the close of the deal on Thursday, Matthias Rebellius, a board member at Siemens and CEO of the German group's smart infrastructure business, told Reuters that Heliox is "a perfect expansion of our business".

Terms of the deal have not been disclosed.

"Together with Heliox we're now perfectly positioned for EV charging technology end to end across different sectors and segments," he said.

Rebellius added that Heliox has a strong U.S. presence, which is an important market for Siemens.

The Dutch charger maker has developed software to manage charging fleets of vehicles and charger hardware that will also boost Siemens' position in the market, he said.

The company's competitors for chargers for larger vehicles include ABB, Sweden's Vattenfall and ChargePoint.

According to industry estimates cited by Rebellius, the global market for electric bus and truck chargers should see compound annual growth of 45% over the next three years as fleets speed up the transition to zero-emission models.

"There's huge, huge growth and huge potential," Rebellius said. "We are definitely targeting growth rates in the high double digits and we will be... among the top three globally."

(Reporting by Nick Carey; editing by Jason Neely)

By Nick Carey