Hydrogen fuel cell cars aren’t all that rare in experimental form. Almost every car maker worth its salt has built one during the past couple of decades.
What has prevented them from progressing past the prototype stage is principally the cost of the precious metal (typically platinum) required for the fuel cell, the cost and challenge of storing enough hydrogen in the car to run the fuel cell, the limited availability of hydrogen and concerns about the robustness of unproven technology.
Toyota is coy about the cost of the Mirai’s 114kW polymer electrolyte fuel cell, but it arrives at a time when the technology has become vastly more affordable, plummeting from hundreds of dollars per kilowatt of generating capacity required to just tens.
The Mirai’s fuel cell is about the size of a conventional petrol tank and sits under the front seats. In durability trials, it is claimed to have powered the car to more than 60,000 miles in less than six months without any hiccups and cold-started in temperatures as low as -30deg C.
In the engine bay is a 152bhp electric motor, borrowed from a Camry hybrid and driving the front wheels via single-speed gearing. Behind it are two high-pressure hydrogen tanks (one for storage, one for expansion) and a high-voltage nickel-metal hydride drive battery, in order that the Mirai can regenerate and store energy under braking like any other Toyota hybrid.