Mirai powertrain. Click to enlarge.

Toyota FC Stack. The new Toyota FC Stack achieves a maximum output of 114 kW (153 hp). Electricity generation efficiency has been enhanced through the use of 3D fine mesh flow channels. These channels—a world first, according to Toyota—are arranged in a fine three-dimensional lattice structure and enhance the dispersion of air (oxygen), thereby enabling uniform generation of electricity on cell surfaces. This, in turn, provides a compact size and a high level of performance, including the stack’s world-leading power output density of 3.1 kW/L (2.2 times higher than that of the previous Toyota FCHV-adv limited-lease model), or 2.0 kW/kg.

The compact Mirai FC stack generates about 160 times more power than the residential fuel cells on sale in Japan.

Each stack comprises 370 (single-line stacking) cells, with a cell thickness of 1.34 mm and weight of 102 g.

The amount of water on fuel cell electrolyte membranes has a substantial influence on electricity generation efficiency. Control of the amount of water is carried out using an internal circulation system for circulating the water created when generating electricity—meaning the Toyota FC Stack, unlike systems used in all other previous Toyota fuel cell vehicles, does not require the use of a humidifier.

The stack, with a significantly reduced size, fits under the front driver and passenger seats.

FC Boost Converter. A new compact (13-liter), high-efficiency, high-capacity converter has been developed to boost power generated in the Toyota FC Stack to 650 volts. Increasing the voltage has made it possible to reduce the size of the electric motor and the number of Toyota FC Stack fuel cells, leading to a smaller, higher-performance Toyota Fuel Cell System, thereby reducing system costs.

The boost converter is mounted just forward of the fuel cell stack.

“Our fuel cell vehicle runs on hydrogen that can be made from virtually anything, even garbage.” —Akio Toyoda, Toyota Motor Corporation President/CEO

High-pressure Hydrogen Tanks. Two tanks with a three-layer structure made of carbon fiber-reinforced plastic and other materials are used to store hydrogen at 70 MPa (approximately 700 bars or 10,000 psi). The three layers are:

• Inner layer: plastic liner (prevents hydrogen leakage)
• Middle layer: carbon fiber reinforced plastic (structural element)
• Surface layer: glass fiber reinforced plastic (protects outer surface from abrasion)

Compared to the high pressure hydrogen tanks used in the Toyota FCHV-adv model, tank storage has been increased by approximately 20% while both weight and size have been reduced to achieve a world-leading 5.7 wt% .

The front tank holds 60.0 liters, the rear tank, 62.4 liters. Total hydrogen storage mass is about 5 kg.

Under the hood. (Power control unit on top, traction motor beneath.) Click to enlarge.

Electric traction motor and battery. Current-generation hybrid components were used extensively in the fuel cell powertrain, including the electric motor, power control and main battery. The electric traction motor delivers 113 kW (152 hp) and 335 N·m (247 lb-ft) of torque. Toyota is using a NiMH battery in the Mirai.

Safety. Toyota began fuel cell development in Japan in the early 1990s and has developed a series of fuel cell vehicles, subjecting them to more than a million miles (1.6 million km) of road testing. In the last two years alone, fuel cell test vehicles have logged thousands of miles on North American roads. This includes hot testing in Death Valley, cold testing in Yellowknife, Canada, steep grade hill climbs in San Francisco and high altitude trips in Colorado. The Toyota-designed carbon fiber hydrogen tanks have also undergone extreme testing to ensure their strength and durability in a crash.

This extended legacy of research and development is reflected in Mirai’s safety and reliability. At Toyota’s advanced Higashifuji Safety Center, the vehicle has been subjected to extensive crash testing to evaluate a design specifically intended to address frontal, side and rear impacts and to provide excellent protection of vehicle occupants. A high level of collision safety has also been achieved to help protect the fuel cell stack and high-pressure tanks against body deformation.

The high pressure hydrogen tanks have excellent hydrogen permeation prevention performance, strength, and durability. Hydrogen sensors provide warnings and can shut off tank main stop valves. The hydrogen tanks and other hydrogen-related parts are located outside the cabin to ensure that if hydrogen leaks, it will dissipate easily.

The vehicle structure is designed to disperse and absorb impact energy across multiple parts to ensure a high-impact safety performance that protects the Toyota FC Stack and high-pressure hydrogen tanks during frontal, side or rear impacts.

The Toyota FC Stack frame is constructed from a newly-developed thermoplastic carbon fiber-reinforced plastic, which is light, strong, and easily mass-produced. This protects the Toyota FC Stack by absorbing impact shocks from road bumps and other road interference.

In addition to the physical safety measures, the Mirai features a full range of advanced drive assistance and safety systems appropriate for next-generation vehicles.

• A Pre-collision System (with millimeter-wave radar) helps prevent collisions or reduce collision damage through alerts and brake control if a high likelihood of collision is detected.

• A Lane Departure Alert system uses a camera to detect white or yellow lane markings and alerts the driver when the vehicle is about to deviate from its lane.

• Drive-start Control limits sudden starts or sudden acceleration during gear-shift operation.

• A Blind Spot Monitor uses radar to detect vehicles in adjacent lanes and helps rear view confirmation when changing lanes.

Design. Like the Prius, Toyota designed the Mirai to be immediately recognizable. A new technique has been employed in the front face design to emphasize the left and right grilles that draw in air for the oxygen supply and for FC system cooling. The novel front face is intended to underscore the vehicle’s individuality.

Toyota says that the side profile evokes the flowing shape of a droplet of water to express the vehicle’s characteristic of drawing in air and emitting water. The roof-side rails and hood appear to pop out of the body to create the impression of a low-to-the-ground vehicle while communicating a futuristic feeling.

The rear of the vehicle presents a bold profile with a trapezoidal shape extending from the license plate garnish to the bottom of the bumper corners and out toward the wheels, while the top of the bumper emphasizes width and expresses a powerfully stable stance. It is also to create an agile and clean impression of air passing through and under the bumper.

The headlights exhibit high-tech and sophisticated luxury through a novel design that presents an ultra-thin profile with an inline arrangement of four LED lights plus visible heat sinks and other optical equipment. The front turn signals and clearance lights are separate from the headlights, contributing to an ultra-thin headlight profile at the same time as merging with the side grilles. This creates an advanced clean design with aerodynamics that improve airflow.

The Mirai comes with 17-inch aluminum wheels that have been made lighter using an engraving process.

Handling stability and quietness. Handling stability and ride comfort are both improved through the location of major parts such as the Toyota FC Stack and high pressure hydrogen tanks centrally under the floor to achieve a low center of gravity and superior front-and-rear weight distribution, as well as the use of a high-rigidity body, which features enhanced rigidity around the rear suspension.

The full under-floor cover and aerodynamically designed clearance lights reduce wind resistance and contribute to improved fuel efficiency and handling stability. Aero fins employed at the side of the rear combination lamps also improve straight-driving stability.

Outstanding quietness is achieved by electric motor drive at all speeds and reduced wind noise, plus full sealing of all body parts, and the use of sound-absorbing and sound-blocking materials optimally arranged around the cabin, including the use of noise-reducing glass for the windshield and all door windows.

Brake support mode makes efficient use of regenerative braking and improves braking performance when the driver wishes to greatly reduce vehicle speed such as when negotiating long downhill sections of road.

Large external power supply system. The Mirai will come with a power supply system with a large capacity of approximately 60 kWh and maximum power supply capability of 9 kW for use during power outages, such as those following natural disasters. (After DC/AC conversion by power supply unit. Power supply capacity varies according to power supply unit conversion efficiency, amount of remaining hydrogen and power consumption.) When a power supply unit is connected, it converts the DC power from the CHAdeMO power socket located inside the trunk to AC power and can power a vehicle-to-home16 system or a vehicle-to-load system. Consumer electronics can also be connected directly and used from the interior accessory socket (AC 100 V, 1,500 W).

Sales and Marketing. In the US, customers will be able to take advantage of Mirai’s $499 per month/36 month lease option, with $3649 due at lease signing, or purchase the vehicle for $57,500. With combined state and federal incentives of $13,000 available to many customers, the purchase price could potentially fall to below $45,000.

The vehicle will be matched by a comprehensive, 360-degree Ownership Experience offering a range of services, including:

• 24/7 concierge service, with calls answered by a dedicated fuel cell representative;

• 24/7 enhanced roadside assistance, including towing, battery, flat tire assistance, trip interruption reimbursement, and loaner vehicle;

• Three years of Toyota Care maintenance, which covers all recommended factory maintenance, up to 12,000 miles annually;

• Eight-year/100,000-mile warranty on fuel cell components;

• Entune and three years of complimentary Safety Connect, including hydrogen station map app; and

• Complimentary hydrogen fuel for up to three years.

Building a convenient refueling infrastructure. In addition, Toyota continues to support the development of a convenient and reliable hydrogen refueling infrastructure. Research at the University of California Irvine’s Advanced Power and Energy Program (APEP) has found that 68 stations, located at the proper sites, could handle a FCV population of at least 10,000 vehicles. Earlier post. Those stations are on their way to becoming a reality. By the end of 2015, 3 of California’s 9 active hydrogen stations and 17 newly-constructed stations are scheduled to be opened to the general public, with 28 additional stations set to come online by the end of 2016, bringing the near-term total to 48 stations.

Nineteen of those 48 stations will be built by FirstElement Fuels, supported by a $7.3 million loan from Toyota. The company has also announced additional efforts to develop infrastructure in the country’s Northeast region. In 2016, Air Liquide, in collaboration with Toyota, is targeting construction of 12 stations in five states – New York, New Jersey, Massachusetts, Connecticut, and Rhode Island.

The Prius analogy. In both the Japan and US introductions of the Mirai, Toyota executives carefully drew a comparison between the launch of the Mirai and the development and launch of the first Prius. For example:

A quick flashback to the year 2000. I am just starting my new job as the GM in the Los Angeles region, our largest company owned distributor covering Southern California. Our first major task...launch a new Prius, a new hybrid. Fuel is very affordable and there is no market or awareness for this new technology, a gas electric hybrid.

Our dealers were apprehensive but trusted our vision and instincts. We never worked harder to produce 5500 sales in six months in my life. As you know by 2012 we were selling over 235k Prius family sales a year, and it has become the best selling vehicle in California the last two years in a row.

And here we are again, at another turning point in technology. Launching a disruptive technology is a challenge, it’s true… But we did learn a thing or two when we launched Prius 15 years ago… When you launch a new technology, education is key. We learned this with Prius.

—Bill Fay, Group Vice President, Toyota Motor Sales and General Manager, Toyota Division

And:

As John pointed out in his introductions of me and Chairman Uchiyamada, we have worked together for many years on this vision of future mobility… involving first the hybrid Prius… and now the fuel cell Mirai. I cannot help but think that to some people, our collaboration—our adventurous road trip—must seem quixotic; idealism without regard for practicality. I, of course, would not agree with that… but at least I know… who is Don Quixote and who is Sancho Panza.

Uchiyamada-san said earlier that Hydrogen, and Hydrogen fuel cell technology will be a societal and economic game changer… and that it will be the fuel for the next century. Frankly speaking, I think I feel a little more optimistic than that. I believe this technology… is going to change our world; and sooner… rather than later. That, in fact, is why we named this car Mirai. We see it as the vehicle that will open the door to future for Toyota.

Of course not everyone agrees. For many years, the use of hydrogen gas to power automobiles has been seen by many smart people as a foolish quest. That point of view is much like opinions 20 years ago of how the Prius hybrid was nothing more than a science project… and economically unfeasible. Sometimes change can happen quickly; a disruption of convention for the better. Other times, change takes persistence. And a long view.

… for any product to revolutionize a market… it must fit neatly and comfortably and conveniently into the everyday lives of the consumer, accomplishing more, without asking for more, of the owner. For all of its technical wizardry, its zero emissions and its bold styling, it needs to be, at the end of the day a regular car. That’s what made Prius a success. We hope that is what makes Mirai a success as well.

—Satoshi Ogiso, Managing Officer, Toyota Motor Corporation

Ogiso was one of the original engineers in the Prius program and later the chief engineer for the Prius program.

And:

Prius means “go before,” and for nearly twenty years, Prius paved the way by demonstrating to mainstream buyers that the future in mobility would include electric motors. But “the future” that Prius went before will be the car we will talk about today: the Toyota Mirai hydrogen fuel cell electric vehicle. … The gas-electric hybrid technology in the first Prius blazed a new trail, that many critics said could not be blazed. The hydrogen fuel cell technology in the new Mirai will do the same.

—Takeshi Uchiyamada, Chairman of Board, Toyota Motor Corporation

Expectations. Despite the two decades of work preceding Mirai, Toyota views its introduction as only an early step on a much longer road that will entail not just further vehicle development, but also major progress in hydrogen production, infrastructure development, and so on.

Initial delivers may be slow, Toyota noted in Japan, as the vehicles are going to be built meticulously.

We are just at the starting point. Today is not the day of completion and perfection. We will continue our efforts with fresh devotion. Mirai contains two innovations: innovation for mobility, and innovation to realize a hydrogen based society.

Many challenges still remain before these two innovations can be perfected at higher levels. Production, sales and service systems all need to be reinforced for customer to use them with a sense of security. Despite those challenges, Toyota has decided to introduce this vehicle and to take a step forward toward making a difference for the future.

—Mitsuhisa Kato, Executive Vice President, Toyota Motor Corp. at the Japan launch of Mirai