The new unit will come up on the grounds of its Honsha plant in Toyota City near the automaker's global headquarters, the company said in a statement. It is also constructing a dedicated line at the nearby Shimoyama plant to produce tanks for storing high-pressure hydrogen gas inside vehicles.

Toyota declined to give details about their latest investment in this technology, but said mass production of components will begin around 2020, enabling the company to meet its target for global annual fuel cell vehicle sales of more than 30,000 units, including passenger cars and buses.

"As a technology, fuel cells are mature and ready to scale up," Toyota said in a statement. "In order to encourage more widespread use of hydrogen-powered zero-emission vehicles, popularization needs to start by the 2020s."

Toyota already sells the Mirai sedan, the world's first mass-market fuel cell electric vehicle (FCEV), in Japan, in the United States and also some European countries. The model starts at about 7.2 million yen (49,242 pounds) in the Japan market.

Due to its high cost and complexity of building its components, the Mirai is produced in small lots. Only around 5,300 units have been sold since its 2014 launch, a fraction of regular production models.

Mass manufacturing of the two components - hydrogen fuel cell stacks and hydrogen tanks - will enable Toyota to lower the price of FCEVs, and expand its fuel cell technology.

Honda Motor Co and Hyundai Motor Co also manufacture fuel cell vehicles, while other automakers are also developing the technology. However, many automakers, including Nissan Motor Co and Tesla Inc, are focussing on all-battery electric cars as a solution to reduce vehicle emissions.

Toyota, which developed the Prius, the world's first gasoline hybrid vehicle, sees hydrogen FCEVs as a zero-emission alternative, which requires less time to refuel compared with the time it takes recharge electric vehicle batteries.

(Reporting by Naomi Tajitsu, Editing by Robert Birsel and Sherry Jacob-Phillips)