Hydrogen cars: fuel cell electric vehicles explained

Electric and hybrid cars are growing in popularity, in part because they help reduce the amount of carbon emissions released into the atmosphere. But they’re not the only option for more eco-friendly driving. Hydrogen fuel cell electric cars sound like science fiction, but these vehicles have been around longer than you might think. If you’re interested in another combustion engine alternative, here’s how they work.

How a hydrogen fuel cell works

Hydrogen vehicles are a type of electric car that uses fuel cells to power the engine instead of relying primarily on a lithium-ion battery; they don’t burn fuel like gas-powered cars. As with electric vehicles, hydrogen cars generate no harmful emissions – the only byproduct is water vapour. Since they are electric vehicles, you will also hear them referred to as fuel cell electric vehicles (FCEV).

Fuel cells are similar in design to a lithium-ion battery: they have an anode, a cathode and a catalyst that triggers the separation of electrons and protons from the hydrogen gas pumped into them. Like lithium-ion cells in an electric vehicle battery, hydrogen cars are equipped with multiple fuel cells operating simultaneously to generate electricity. This set of cells is called the hydrogen fuel cell.

Hydrogen from fuel tanks on board the car combines with oxygen inside the fuel cell to generate electricity through a process called reverse electrolysis. Electrons are stripped from the hydrogen gas, sent through the circuit to power the engine, and combine with oxygen on the other side of the circuit to form water vapor, which is vented via the engine exhaust. the car.

The hydrogen tank, battery and electric motor all work together to power the FCEV. (Picture: BMW)

Electricity generated by hydrogen fuel cells can take two paths(Opens in a new window), Depending on the situation. Energy powers the electric motor directly or charges a small lithium-ion battery that helps power the motor and can store energy for later use. This battery also captures energy from the vehicle’s regenerative braking system for later use and stores excess energy from the fuel cell during low-energy driving. If more demand is placed on the engine, the battery kicks in to help.

Refueling and autonomy

toyota mirai

The Toyota Mirai fuel cell vehicle has an estimated range of 402 miles (Picture: Toyota)

Refueling an FCEV’s hydrogen tanks is about as fast as refueling a gasoline-powered car, a serious advantage that hydrogen cars have over battery-electric vehicles. All you have to do is drive to the gas station, connect the hose, and the tank is full in about five minutes.

An FCEV can have multiple hydrogen tanks on board. Since hydrogen can be highly flammable(Opens in a new window) if not handled properly, these fuel tanks are thick-walled, pressurized and crash-tested to ensure safety. Fail-safes are also built into the vehicle to ensure the hydrogen is dispersed and released if, for example, the fuel cell is removed or overheats.

Another advantage of hydrogen cars over battery electric vehicles at the time of this writing is their longer range. FCEVs can travel 300 to 400 miles before needing to be refueled, according to California’s Drive Clean initiative(Opens in a new window). All-battery electric vehicles, on the other hand, have an average range of around 250 miles(Opens in a new window) at the time of this writing.

The Challenges of Fuel Cell Vehicles

real hydrogen zero station

True Zero hydrogen fueling station (Photo: True Zero)

Fast refueling, electric power and the only by-product is water – sounds like the perfect green vehicle, doesn’t it? Well, it could be, but unlike electric vehicles, FCEVs just aren’t here yet.

For starters, although they have a longer range than EVs, FCEVs cost more to refuel, in part because hydrogen is so expensive to produce. It may be the most abundant element on the planet, but refining it into a form that can propel a vehicle takes effort, and that effort is reflected in the cost per tank.

FCEV refueling infrastructure is also sorely lacking at the moment. There are less than 400(Opens in a new window) FCEV refueling stations worldwide, although there are efforts to build more stations; the United States aims to have 1,000 online by 2030. Still, that’s far fewer hydrogen refueling stations than electric vehicle charging ports, of which there were about 110,000 in the States -United.(Opens in a new window) from September 2021.

Another challenge facing FCEVs is that while they themselves can operate emission-free, plants that create their fuel with hydrogen often do so by burning fossil fuels in a process called steam reforming.(Opens in a new window). If this continues, FCEVs won’t do as much for the environment as they could, and you can’t really call them zero-emission vehicles.

Alternative processes(Opens in a new window) under study include water electrolysis, which uses a renewable source like solar energy to generate electricity that can be used to separate hydrogen from water.

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FCEV versus EV

mustang mach e

Ford’s Mustang Mach-E, an example of a battery-electric car (Photo: Ford)

Hydrogen vehicles have a lot in common with battery-powered cars such as the Ford Mustang Mach-E (above) and the Tesla Model 3. Battery electric vehicles and FCEVs use electricity instead of fuel, they both have electric motors and on-board batteries, and neither emits harmful gases. The differences come down to infrastructure, fuel and availability.

Battery electric vehicles have a more robust infrastructure for public charging than hydrogen vehicles. Although not yet as widespread as gas stations, there are now thousands of electric vehicle charging points in the United States. Meanwhile, all hydrogen fueling stations in the United States are located in California(Opens in a new window)so long road trips are out of the question.

The cost of refueling is also worth considering. As it is currently more expensive to produce hydrogen gas for FCEVs, refueling your FCEV costs more than for an electric car. However, a hydrogen vehicle can be refueled several times faster than an electric vehicle and can store excess electrical energy in its battery, allowing it to recharge while driving. Battery electric vehicles, on the other hand, need to be plugged into the grid to regain most of their energy.

Hyundai Nexo

The Hyundai Nexo fuel cell electric vehicle has been on the market since 2019. (Photo: Hyundai)

Of course, the biggest problem is that FCEVs aren’t yet widely available in the United States. Only a few manufacturers sell them to the public; The Toyota Mirai and Hyundai Nexo are currently the most popular names in racing.

Despite hydrogen’s limitations, countries around the world see it as a viable alternative energy source for everything from cars to buses to planes.(Opens in a new window). If we can find a cost-effective way to make hydrogen production more environmentally friendly and build the necessary fueling infrastructure, FCEVs could mean a huge leap forward for green transportation.

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