Matt McClory is the manager of the fuel cell vehicle group at Toyota Technical Center in Torrance, California. His primary responsibility is the development, testing and evaluation of prototype fuel cell vehicles. In addition, he is involved in supporting the development of the hydrogen-refueling infrastructure.
What countries get the Mirai?
Japan, USA and Europe. The U.S. is California-only for now but we’re expecting sales to expand into the northeast region in 2017.
How is developing a hydrogen fuel cell vehicle different from a conventional vehicle?
From a development process standpoint, we go through the same steps. Whether it’s an advanced diesel engine, an advanced gasoline engine, or a fuel cell, the process for development is the same. The difference is that the timeline is going to be longer for more advanced technologies. When we’re talking about technologies that are already understood in other applications or tweaking something that already has a foundation, development timelines are shorter. Figure it’s about a 3-5-year timeline for developing a new vehicle or powertrain, depending on what technologies are involved. The timeline is basically implementation and testing.
Obviously, safety is a big part of the development with a hydrogen fuel cell vehicle.
From a safety standpoint, the key philosophy is that we minimize the amount of high-pressure hydrogen that we have and prevent leaks. Our system only keeps high-pressure hydrogen in the tanks, we don’t have a bunch of lines strewn across the car carrying high-pressure hydrogen. The amount of hydrogen we have on the car outside of the tanks is a fractional percent. We have about 11 pounds of hydrogen in the tanks and less than 1% of that in the lines and manifolds. This minimizes the amount of hydrogen that we have to deal with to make sure it doesn’t leak.
We’re also monitoring the use of the hydrogen. When it’s consumed in the fuel cell stack, we know where basically every molecule is going. We know what’s being consumed in the fuel cell system and we know how much is in the tank. So, we know that if there’s a variance then there is a problem or a leak and shut the system down. Also, there are valves inside the tanks that are normally closed, so when power gets cut due to an accident or deactivation of the system, the valves will close immediately and automatically. These are basically spring-loaded valves that shut when they aren’t powered.
Additionally, the tank system is designed to maintain system integrity if there’s a fire or a collision. That’s been verified through regulated crash testing as well as other tests we do in house. We have a lot of confidence through all the tests that we have done that the hydrogen system is as safe as a conventional vehicle.
What have been some other specific challenges with the development of Mirai?
If the water that gets produced inside a fuel cell freezes, it blocks the passages and you no longer have power. Additionally, it may damage the fuel cell. One of the things that we do is prevent the water from freezing. There is a technique you can do inside the fuel cell where water doesn’t act like a normal liquid, but is in a polymer-like state.
What were the key test and development facilities for Mirai?
The design of the vehicle took place in two different areas — Hagashi Fuji, our research and test facility at the base of Mount Fuji, and our design development group is in Toyota City. The cold test facility is in Japan — in Shibetz, Helkaido (northern Japan).
The other part is our development in the U.S. We test on local roads in Los Angeles as well as Death Valley for hot weather testing. We also go to places like Fairbanks, Alaska and Canada for cold weather testing. We use Colorado for high altitude testing. These different places make up the portfolio of testing locations.
How much platform and component sharing does the Mirai have with other Toyota models?
The platform came from the global MC platform, the same platform as the Prius V and the Lexus HS. It was adapted for the fuel cell, so there were numerous structural enhancements made to accommodate the hydrogen tanks and how the fuel cell stacks sit underneath the vehicle.
The big success with the Mirai fuel cell vehicle is actually not the technology per se, but the cost reduction. We developed the core technology for the previous-generation fuel cell vehicle, which was based on the Highlander — the Toyota FCHV-adv (Fuel Cell Hybrid-Vehicle Advanced). We had a fleet of just over 100 of those vehicles running around the U.S. and other locations. That validated that the technology was ready to go to market. The Mirai fuel cell vehicle was developed to bring costs down and make something that we can serially produce in a factory for the retail market.
We not only took the platform from an existing vehicle line, but also used the power electronics. That was one of the key things for cost reduction. The power electronics were taken from a conventional vehicle such as the Camry Hybrid and Lexus RX Hybrid. Components such as the high-voltage battery, the inverter, and the traction motor were all taken from those platforms to help reduce costs.
We then developed a new converter to boost voltage out of the fuel cell to mate it with the high-voltage BUS that’s driving these other components. The other benefit of having the fuel cell booster is that it allowed us to cut the size of the fuel cell, which reduced the cost of the fuel cell. So, even though we’re adding another component and there are costs associated with that, the overall net effect was a cost reduction due to sharing components.
Why use nickel-metal hydride batteries versus lithium ion?
Cost. Lithium ion (li-ion) batteries are typically suited for something where you want more energy density, not power density. You can make a li-ion be both energy and power dense, but we already had a nickel-metal hydride setup and we know the pedigree and the costs very well. We’re not looking for energy density; we’re looking for the same type of energy size we’d have with a Prius-size hybrid vehicle as far as power. So, the battery pack gives you that additional boost in addition to the fuel cell for making the system more efficient.
For the future, we’re looking for li-ion prices to come down but, again, at the point in time where we made the design freeze for the Mirai, the li-ion battery that we had in the pipeline wasn’t at the level of development that we wanted it to be for us to consider it as an option.
What is Toyota doing about the infrastructure shortcomings of hydrogen refueling stations?
Fuel station development is kind of the third part of our three-legged stool. One leg is the vehicle and the other is something we call codes and standards — to make sure the design framework exists to the level that it needs to. So, it’s supporting fuel stations and putting vehicles in the market place. From a hydrogen standpoint, Toyota develops relationships and financial arrangements with companies in the business.
One company is called, First Element. Another is Air Liquide, which is developing 12 stations in the northeast USA. First Element was awarded 19 stations in California. Today we have 21 stations, with about 15 of those from First Element. So, the rapid growth of fueling stations in California came from Toyota’s involvement in bringing up First Element in conjunction with an equipment supplier called Air Products in order to accelerate the build out of stations in the area where we’re launching the vehicle.
What can be done to lower the cost of future hydrogen fuel cell vehicles in the future?
It’s bringing the cost of the hydrogen storage tank down. It’s also reducing the cost of the fuel cell stack even further. Those are the two key areas from a cost standpoint. The Mirai was a 95% cost reduction compared to the previous-generation Highland-based fuel cell vehicle. Doing mass production or production on large-scale vehicles does not necessarily bring the costs down a significant amount. There is a certain amount of cost that comes down with mass production though economies of scale, but the first level of cost reduction comes in the design of the technology and manufacturing costs.