Nissan has sold more battery-electric cars than any other automaker by roughly a factor of two.

But while Japanese rivals Honda and Toyota bet heavily on hydrogen fuel cells, Nissan still appears reticent about the technology.

Now, the company's boss says Nissan is developing a fuel-cell car, but on a relaxed timetable.

DON'T MISS: Nissan 'Quite Optimistic' About Electric Cars, Holding Off On Hydrogen (Dec 2014)

Nissan will not launch a fuel-cell car until around 2020, as the company is "not in a hurry," CEO Carlos Ghosn told Automotive News (subscription required).

At last week's Tokyo Motor Show, Ghosn said Nissan is not under the same amount of pressure as other carmakers, because it already has a "zero-emission solution": the Leaf electric car.

He said Nissan believes it is "too early" to launch a fuel-cell car, but that it plans to put one in showrooms in "like four to five years."

2016 Nissan Leaf

2016 Nissan Leaf

Meanwhile, Hyundai has already delivered several dozen Tucson Fuel Cell crossovers, Toyota began U.S. deliveries of the 2016 Mirai last month, and Honda will launch its 2017 Clarity Fuel Cell next year.

Ghosn said high development costs and lack of fueling infrastructure make fuel-cell cars a tricky proposition at this time.

ALSO SEE: Hybrid & Hydrogen, Or Electric? Toyota, Nissan Battle Over Future Green-Car Tech (Jun 2014)

"We're facing already a problem with the charging infrastructure in electric cars," he said, "You can imagine the problem we're going to have with fuel cells."

Nissan is currently partnering with Honda and Toyota to underwrite some of the costs of fueling-station construction in Japan.

Hydrogen station in Amagasaki City, Japan

Hydrogen station in Amagasaki City, Japan

The carmakers will cover up to one third of operational costs of stations that apply for the program, until the point at which infrastructure and fuel-cell vehicles in general have become well established.

However, he said he understands why rivals that haven't developed mass-market electric cars are eager to put fuel-cell vehicles on sale as a zero-emission alternative.

MORE: Daimler, Ford, Nissan Agree To Share Hydrogen Fuel-Cell Costs For 2017 Or Later (Jan 2013)

If Nissan really does launch a fuel-cell car over the next five years, it could borrow some technology from Daimler, which Nissan has an ongoing partnership with.

In addition to potential fuel-cell collaborations, Nissan is using a Mercedes-Benz platform for its Infiniti Q30 and QX30 compact luxury cars.

[hat tip: Teng Yang]

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