Mirai Reflects Toyota’s Faith in Fuel-Cell Future

Toyota plans to match last year’s output of 3,000 units this year and again in 2019. But its FCV program targets no fewer than 30,000 sales – including 12,000 in Japan – early in the next decade, including Mirais and anything else that might be in the pipeline.

Roger Schreffler

April 23, 2018

5 Min Read
Thirteen Toyota workers turn out 13 Mirai hydrogenfuelcell vehicles daily
Thirteen Toyota workers turn out 13 Mirai hydrogen-fuel-cell vehicles daily.

TOYOTA CITY, Japan – Toyota hit a major target by producing 3,000 Mirai sedans in 2017, the hydrogen-fuel-cell vehicles’ best year since rolling out of the automaker’s Motomachi plant in December 2014.

Toyota plans to match last year’s output of 3,000 units this year and again in 2019. But its FCV program targets no fewer than 30,000 sales – including 12,000 in Japan – early in the next decade, including Mirais and anything else that might be in the pipeline.

Through the first week of March, the automaker had produced a cumulative 6,548 units including 4,034 for export.

WardsAuto took the occasion of the recent International Hydrogen and Fuel Cell Expo held in Tokyo, where Toyota made a key presentation, to visit the automaker’s Motomachi plant, Toyota’s first plant dedicated to car production 59 years ago.

Toyota is producing 13 Mirais per day in a two-shift operation (6.5 hours per shift, with overtime averaging 15 minutes), close to capacity and double the number when the plant opened.

The plant incorporates both new and old processes. Chief among the new is a computer-controlled hydrogen leak tester. Among the old is the training of line workers, mostly in their early 30s, to do every assembly task and become a new generation of master craftsmen or takumi.

In the final-assembly shop, 13 specially trained workers, 20% of them women, put the car together beginning with wiring, headliner, interior and exterior lighting and rear bumpers.

Takt time at each of the shop’s three stations, as well as a parallel seat-assembly substation, is 70 minutes, meaning it takes 3.5 hours (210 minutes) for each Mirai to move through the shop.

Stamping and welding are done in a separate building along with Lexus GS and LC models also produced at the plant before the Mirai moves to the paint shop with the GS and LC.

There, the FCV undergoes a special Lexus paint process – as many as five base coats, two more than standard Toyota cars, including a middle polishing process that makes the surface as glossy as a mirror. Quality inspectors examine the finish under different spectrums of light before releasing the car to the final-assembly shop.

End-of-line quality tests after the car leaves the assembly shop are the same for the Mirai and Lexus models.

Following painting, the body shell is transported to the assembly shop in a covered trailer. It is unloaded manually and pushed on a hydraulic dolly to the shop floor.

Upon entering the shop, the car’s four doors are detached and manually taken to the seat-assembly substation where a single worker assembles 35 main parts per door during the 70-minute takt period. The doors then are reattached.

Some 1,700 components are delivered to the shop from two nearby fenced-in storage areas. All are delivered just in time, with employees referencing an electronic kanban scheduling system.

To the first station in the shop go rear combination lamps and rear bumper, roof lining, instrument-panel components including the car’s HVAC system and the nickel-metal-hydride battery pack.

The main powertrain components, hauled by a small tractor to the second station, include the fuel-cell stack, hydrogen fuel tanks, boost converter, inverter and electric motor. Together with the driveshaft, front and rear axles, front suspension and other chassis components – all assembled separately – these make up the chassis module, which is lifted into the car. The front bumper and wheels are attached after the chassis module is installed.

The Mirai’s two hydrogen tanks, shaped differently for packaging purposes, have been trucked to Motomachi from Toyota’s Honsha plant 3.5 miles (6 km) away. Combined, the tanks hold 12 lbs. (5 kg) of compressed hydrogen gas. They give the car a 312-mile (500-km) range.

Before being lifted into the car’s body, the tanks are checked for leaks using helium. Due to safety concerns involving hydrogen, the car is shipped from the Honsha plant with a virtually empty tank.

Installed at the third station are seats, window glass, interior trim, steering wheel and inverter cover.

Toyota wants to train every worker in the shop to be able to assemble the entire car. “If they can do that, they can work at any of our plants anywhere in the world,” says Takao Minami, a manager in the plant’s administration division.

What comes next for the Mirai, and by extension for the Motomachi plant, is not clear. When Toyota launched the car in late 2014, it said it would lease or sell 30,000 fuel-cell vehicles annually by 2020.

The assumption has been that these would be Mirais. Nevertheless, there is speculation in the media that a smaller version of the FCV is in the pipeline and could be ready in time for the 2020 Summer Olympics in Tokyo.

Additionally, a senior Lexus official does not rule out the possibility of adding a fuel-cell-powered model to the Toyota luxury brand’s range.

The Japanese government’s roadmap calls for sales of all FCV brands to reach 40,000 units in 2020. The number is projected to grow to 200,000 in 2025, when the government hopes the price of an FCV will match that of a hybrid, and to 800,000 in 2030.

Clearly, the current Motomachi operation will not be able to meet Toyota’s production target for 2020, when the automaker plans to introduce a second-generation Mirai. The plant was not built for daily production of 125 units, the number needed to reach the 30,000-unit threshold. There is no conveyor line and only three cars can be assembled at one time.

In December, Toyota shifted the focus of its FCV development program and in the future will place greater emphasis on buses, trucks and other commercial vehicles. The automaker already is testing a Class 8 truck at the ports of Los Angeles and Long Beach, CA, while in Japan it has reached an agreement with 7-Eleven to begin pilot testing next year.

Subscribe to a WardsAuto newsletter today!
Get the latest automotive news delivered daily or weekly. With 5 newsletters to choose from, each curated by our Editors, you can decide what matters to you most.

You May Also Like