Fuel cells vs. batteries: what’s the difference?
At Umicore, we believe fuel cell electric vehicles are part of the way forward for cleaner mobility. That is why we have been working hard on developing Proton Exchange Membrane (PEM) fuel cell catalysts, doing our part to lead the charge. Now, we want to do more: we also want to spread the word about their technology benefits in a series of 6 episodes on fuel cells.
In episode 4: Fuel cells vs. batteries – What’s the difference?
First off, it is important to note that fuel cells and batteries are two viable solutions to create electric powertrains and thus address the clean energy challenge. Both technologies will have their place as a hybrid solution. Depending on the application, either can be the best answer. It all depends on the needs, demands and conditions of its use.
The single most essential difference between fuel cells and batteries is simple: a battery stores energy which it then uses, whereas a fuel cell generates energy by converting available fuel. As long as you have access to the fuel, you have access to electricity – anytime, anywhere. Interestingly, a fuel cell can also have a battery component to store the energy it is generating.
Besides this, there are 5 additional differences worth mentioning for clean mobility specifically on heavy-duty transport applications:
It is no secret that batteries are more efficient than fuel cells, but when you make the comparison for heavy-duty, long-range trucks, there’s a gamechanger that comes into play: weight. Hydrogen is significantly more energy dense than batteries, which means a fuel-cell pushed powertrain will weigh less. To illustrate, for a 800 kms range truck, the difference can be as much as 2 tons. Consequently, fuel cell technology allows for longer driving ranges and heavier payloads.
Next to the light-weight fuel cell stacks, there are other elements that favor fuel cells over batteries when it comes to distance. The main one being refueling time. Today, a battery-powered electric vehicle may take hours to recharge, while a class 8 truck on fuel cell technology is up and running again in 15 minutes. This makes fuel cells highly appropriate for vehicles that run several shifts a day. On top of that, fuel cells can easily handle temperature changes during a long trip, since they are less sensitive to cold temperatures than batteries.
If a battery dies, there are two options: you either find an outlet to recharge or buy a new one. In other words, organizations with a fleet of electric heavy-duty trucks that run on batteries heavily depend on the grid. To avoid downtime during periods of high demand, they will need to coordinate recharging breaks and space. Not so if they had a fleet of fuel cell-powered trucks. Refueling takes minutes, while downtime due to maintenance also speaks for robust fuel cell technology. Batteries and combustion engines need much more taking care of.
The Hydrogen Council recently published a report “Path to hydrogen competitiveness: a cost perspective” which suggests that hydrogen fuel cells are the choice with lowest-cost to decarbonize both medium and heavy-duty road transport. Three use cases revealed that batteries are less attractive due to the larger size, higher weight and cost of the batteries required, as well as the longer recharging times. The biggest cost drivers for fuel cell technology remain the expensive catalyst materials, such as platinum, but as R&D advances, newer fuel cells require less materials.
Particularly when it comes to transport, infrastructure is often a major hurdle for fuel cells – but they can be for batteries as well. More high-power charging solutions, for example, would drastically reduce the time required for recharging batteries (from hours to minutes) or even allow them to recharge while still in use. In the case of hydrogen fuel cells, the main issue is availability and distribution. The good news: advanced R&D for technologies like electrolysis and liquid organic hydrogen carriers show potential to transform the way hydrogen is transported, stored and used to power fuel cells.