The world's largest automaker is floating research and development beyond its Mirai FCV which has begun slow sales in Japan and is due to begin selling later this year in Europe and California in small numbers.

Toyota has previously defended against criticism saying fuel cells are a long-term play. It is looking 15 years out as infrastructure comes online and markets open up, but projects fuel cell vehicles will in due time take the baton from the hand of the successful Prius line and keep running into the future.

"Mirai" in Japanese means "future," but today the automaker says profits from its other cars will help give the unique electrified vehicles a start. Last year it sold over 10 million cars in all its divisions and these are enabling it to dig deep and give it a proper go.

Plans announced are for 500 billion yen ($4.2 billion) in common equity and unlisted shares with restrictions on transfer to be released for sale to investors tied in for a certain duration.