Countries around the world have pledged to reduce their carbon emissions and reduce the use of fossil fuels in their bid to fight climate change. This has caused many car manufacturers to seek alternative methods of propelling vehicles. Currently, all-electric vehicles (EVs) and hydrogen fuel cell vehicles are the precursors to zero-emission transportation.
But how does new fuel cell technology work and how do these two technologies compare?
How does a hydrogen fuel cell electric vehicle work?
Hydrogen fuel cell cars are powered by compressed hydrogen gas stored in a tank which powers an on-board fuel cell which converts the chemical energy of the fuel into electrical energy. This powers the car’s electric motors. The only waste is water.
The fuel cell comprises several cells. The hydrogen gas enters the anode of the cell and encounters a catalyst which separates the hydrogen atoms into electrons and protons. The electrons are collected by the conductive current collector which supplies the on-board battery and/or the motors.
The range of electric cars depends on the capacity/size of the battery. One of the most expensive all-electric cars, the Tesla Model S, offers a range of 575 km.
On the other hand, hydrogen fuel cell electric vehicles offer greater range with just a small tank of hydrogen. The Toyota Mirai offers a range of 650 km on a full tank of 5.6 kg of hydrogen fuel.
Currently, the infrastructure for refueling hydrogen fuel cell cars is much less compared to the infrastructure for charging electric vehicles.
Safety is a major concern for hydrogen fuel cell cars due to the highly flammable nature of hydrogen. However, modern fuel cell electric vehicles have advanced safety measures to minimize risk. For example, the Toyota Mirai has a patented design to prevent hydrogen leaks and it cuts off the flow of hydrogen in the event of a collision. The fuel tank is stored outside the cabin, so in the event of a leak, the gas escapes.
Electric car batteries also have their safety issues. Lithium-ion batteries can overheat or overcharge and cause injury. In the event of a fire, the batteries can ignite and are difficult to extinguish because the fuel for the fire is not vented.
Automakers have worked to address these issues by regulating temperatures and using multiple sets of smaller batteries to prevent overcharging. Other safety challenges are met well by both types of cars compared to combustion engine cars.
Hydrogen and electric cars produce zero emissions, but by-products such as CO2 are released into the atmosphere during the manufacturing and fuel extraction processes.
Producing hydrogen for fuel cell electric vehicles requires huge amounts of electricity, and manufacturing lithium-ion batteries is also an energy-intensive process. The batteries of electric vehicles are charged with electricity produced mainly from fossil fuels.
Electric cars are expensive, but hydrogen fuel cell cars are a bit more expensive than all-electric cars. There are budget options available for electric cars, but not for hydrogen fuel cell cars.
Hydrogen vehicles are also more expensive to refuel. The cost of refueling a Toyota Mirai (5.6kg tank) in India can be around Rs 840-2,800 depending on the hydrogen source (grey or green). On the other hand, to charge an EV battery from a Tata Nexon EV, the cost could be Rs 150-240 depending on the infrastructure (private or public) and the cost of electricity per unit.
Refueling time for fuel cell electric vehicles can be between 3 and 10 minutes, while electric vehicles can take up to 30 minutes minimum and 8 hours maximum to recharge depending on model, type of charger and battery capacity.
First post: STI