PEM fuel cells vs batteries for electric vehicles

Consumers are becoming more environmentally conscious, which is reflected in the growth of electric car usage – with a 35% year-on-year growth from 2022 to 2023. But which power source is better for use in electrical vehicles?

By 2032, the global fuel cell market and lithium-ion battery markets are expected to reach $105 billion and $187 billion, respectively. Both of which are notable power sources for electric vehicles, so let’s take a look at some of the factors that differentiate the two.

How do fuel cells and batteries work?

Fuel cells and batteries work in similar ways; they both produce electricity through an electrochemical reaction and provide a range of power outputs to the systems they sit within. However, unlike batteries that store energy and then release it when required, fuel cells don’t store energy, they use hydrogen as an energy vector, combine it with oxygen from the air and provide power continuously as long as this fuel is supplied.

Fuel cells are made up of cells that produce electricity without combustion. They use hydrogen to produce electrical energy when combined with oxygen from the air and only emit water and heat as by-products, making them a zero-emission electricity generator at point of use.

Similarly, Lithium-ion batteries are also made up of electrochemical cells, they convert the chemical energy stored in them into electrical current which is then supplied to the device that they are powering.

Energy efficiency

Generally, electric vehicles are significantly more energy efficient than traditional petrol or diesel engines, where modern engines have a thermodynamic efficiency of about 30 to 40%.

Batteries experience energy loss during storage, charging and discharging, however they can use between 80-90% of the energy that they store.

In contrast, fuel cells transform around 40-60% of the energy in the hydrogen supplied into electrical power. Additionally, in cold weather conditions, fuel cells are almost as efficient as batteries, as batteries can use up to 40% of their electrical energy for heating.

Charging times

One major benefit of fuel cell-powered vehicles is the refuelling process works just like traditional internal combustion engine (ICE) vehicles. Fuel cell EVs use a tank that is filled with hydrogen in a matter of minutes and would be refuelled in environments just like our petrol forecourts.

In contrast, batteries used in electric vehicles can take anywhere between 30 minutes to half a day to charge and are also sensitive to temperature, taking longer to charge in lower temperatures, especially if using a rapid charger.

Primary energy source

Despite fuel cells and batteries both being part of the solutions towards a greener future, they may both still have some environmental impacts when considering the source of electricity and hydrogen.

For example, the electricity that is used to charge batteries can come from a range of sources, such as wind, hydro or coal, and can therefore still include CO2 emissions depending on this. In a similar way, how the hydrogen fuel used in fuel cells is sourced can also impact its overall environmental footprint. Hydrogen is classified into different colours to highlight how it has been produced – with green hydrogen being the most eco-friendly, and black the least.

Scarcity of materials

Finally, the materials that are used to create batteries are scarce, whereas those used for fuel cells are more readily available. Lithium-ion batteries use a range of metals, such as lithium, nickel and cobalt, all of which are in short supply. Production of these materials is increasing, but possible supply shortages will remain.

In contrast, fuel cells use materials such as aluminium and stainless steel during their construction, which are much more available, and a small amount of platinum.

Fuel cells or batteries?

Both fuel cells and batteries will play a pivotal role in the transition to net zero for the automotive sector. Longer vehicle range, limited reliance on scarce materials and quick refuelling time make fuel cells an ideal choice for commercial EV sector and large passenger vehicles. On the other hand, batteries are a more mature option and cheap zero emission solution for small and medium size vehicles.

Here at Intelligent Energy, we have developed two automotive products. Our IE-DRIVE HD100 is a heavy-duty fuel cell system designed for buses, trucks and stationary power, and the IE-DRIVE 100 is more suited for use in light commercial vehicles and passenger cars. To enquire about our automotive fuel cells or any of our fuel cell technology, please contact us.