As the inexorable transition from gasoline to fully electric transportation cruises on, vehicles running on hydrogen are demonstrating that electric power is ready to step up to whatever challenges are thrown at it. Because their name refers to a versatile and scalable way of producing electricity, a Hydrogen Fuel Cell Electric Vehicle can be pretty much any vehicle currently powered by a motor. So regardless of whether it takes the form of a sporty and luxurious sedan like the 2021 Toyota Mirai, an FCEV is part of a paradigm shift currently underway in the electrification of transportation.
These vehicles marry advanced technologies from a wide range of sectors to enable long range, convenient, zero emission all electric mobility. FCEVs are following a natural evolutionary pathway for zero emission vehicles, one capable of overcoming some of the limiting factors of Battery Electric Vehicles (BEVs). FCEVs also have the potential to open up zero emission personal transportation to those without easy access to charging stations or to people who utilize street parking. Perhaps most importantly, they’re easier to scale from passenger vehicles to heavy duty transportation than electric vehicles that rely on batteries alone.
At its core, an FCEV is an electric vehicle that produces its own electricity through an electrochemical reaction. Using a Hydrogen Fuel Cell stack, the vehicle combines pure Hydrogen and Oxygen across a membrane to create water. Through this process they generate an electric current by what’s known as an electrochemical reaction. Or as Norman Chan of Tested.com put it recently, “There’s a science lab in the car.”
Fortunately for consumers, that science lab is very tidy and usually fits under the hood. That has left the rest of the vehicle up to designers and engineers interpretations, and those have been all over the map. From classic vehicles to race cars, fuel cells have electrified vehicles of many shapes and sizes. Unlike BEVs though, the fuel needed to power them isn’t already flowing into most buildings in the United States. So in 2004, California set out to build the nation's first hydrogen highway. This network of fueling stations helped launch a first generation of FCEVs from manufacturers such as Toyota. Over the last decade, these elements came together and enabled the nascent industry to get vehicles on the road and being driven by the public for the first time in the US.
Toyota recently launched the second generation of its Mirai. With rear wheel drive, a highly symmetrical and balanced internal layout, and sporty visual lines focused on minimizing drag, it offers a luxurious and responsive all electric driving experience. The vehicle demonstrates the practical side of hydrogen too, with an EPA-estimated to the range of 400 miles for the XLE grade and a refueling time of approximately five minutes. By combining an uncompromising commitment to design, enhanced technology features, and an exhilarating driving experience, the 2021 Mirai leads the way in bringing FCEVs into new frontiers.
In order to understand the implications of the FCEV, it’s important to dive a little deeper into what exactly hydrogen is. “It’s everywhere, it runs the sun,” says Chan. As the most common element in the Universe, it holds the distinction of being number one on the Periodic Table of Elements. A bit closer to home, it’s the third most common element on the earth’s surface after oxygen and silicon, and humans have found a correspondingly large number of applications for it. Hydrogen is used for processes in chemical production plants, oil refineries, steel production, food processing facilities, and many others. It’s lighter than the ambient atmosphere and is never found in its pure form in nature, because it really wants to bond with other elements. This quality makes it useful for refining and purifying processes, and is also what makes the electrochemical reaction in a fuel cell possible.
One of the most common misconceptions about FCEVs is that they are competing with electric cars in a winner take all battle for market dominance. This isn’t really possible because a hydrogen fuel cell vehicle is an electric car. Like BEVs, they have batteries and capacitors that provide power, but those are much smaller because they are continually recharged by a hydrogen fuel cell. Which begs the question, what is going on under the hood with the hydrogen fuel cell?
According to Jackie Birdsall, a Senior Engineering Manager for the Fuel Cell Integration group at Toyota, “It’s an electrochemical reaction, which means there’s no combustion happening. There’s no pistons, there’s no compression chamber... It’s a chemical reaction generating electricity on demand.”
In an FCEV, when the accelerator is pressed, it sends a power request. That opens injectors, and hydrogen flows out of its tank towards the fuel cell. Once there, it flows onto one side of two flat plates, called an anode and a cathode. Hydrogen flows onto the anode, and oxygen from filtered outside air flows to the opposite side of the plates onto the cathode. One of the key attributes of hydrogen is that it wants to form bonds with other elements, so when it sees the oxygen on the other side of the fuel cell, it wants to form water. The fuel cell provides the right environment for that to happen. It maintains the ideal heat and humidity, and uses platinum as a catalyst. The hydrogen hits that catalyst and gets activated, meaning its proton gets separated from its electron.
In between the anode and the cathode, there’s a membrane called a Proton Exchange Membrane that allows protons to flow through while holding back electrons. The protons from the hydrogen flow through that membrane to the cathode side, and the electrons look for a path to meet back up with them. On the cathode side of the PEM, the protons from the hydrogen react with the platinum catalyst, enabling a reduction of the O₂ molecules from the outside air. Meanwhile, the fuel cell provides a conductive pathway for the electrons from the hydrogen to flow on, so they follow that pathway around the membrane and meet up with their protons and the oxygen to form water, and the water goes out the tailpipe. When enough of this electron flow occurs, there is a usable electric current, and that current goes through a boost converter to step up its voltage. In the case of the Mirai, the voltage is matched to the level used in the rest of its Hybrid Synergy Drive components, and that directly drives the same types of motors that exist in other electric vehicles.
Hydrogen’s ubiquity, stability and flexibility combine to make a strong argument for it in any debate about how to power our transportation in the future. While there are many theories out there about how that’s going to happen, it’s only when people actually do something and see it being done by others that those theories shift from ideas to reality. For FCEVs, that shift is the 2021 Toyota Mirai. Out on the road today they are demonstrating that with innovation and adaptation, fully electric vehicles can be everything we ask of them.
This story was produced by WIRED Brand Lab for Toyota Mirai.
