In a concerted effort to tackle climate change, countries around the world have announced bans on new vehicles powered solely by internal combustion engines (ICEs), paving the way for an electric vehicle revolution.
Petrol-based fuels used by our conventional ICE vehicles have a high energy density and can be stored easily and quickly. These attributes give us the benefits of being able to travel far with few and short stops for refuelling.
Electric vehicles available today largely employ batteries. Most of these batteries are Lithium-ion, which are incredibly efficient (90 per cent), but have a considerably lower energy density than petrol-based fuels (approximately 30 times less). This means that battery-powered electric vehicles need a lot of batteries, and therefore a lot of weight, to provide performance comparable to conventional ICEs.
The other well-known drawbacks of battery-powered electric vehicles are a short range and a slow charge-time. However, these issues are becoming less prevalent as the technology improves. Taking Tesla as an example, each of the upcoming Semi will boast 500 miles of range and its V3 Supercharger can recharge 75 miles of charge in five minutes. Moreover, the Chinese car battery-maker CATL announced in 2020 a car battery capable of powering a vehicle for 1.2 million miles across a 16-year lifespan. CATL already supplies Tesla, as well as Toyota, Honda, Volkswagen and others.
But there is an alternative being explored for day-to-day road travel: Fuel cells.
Fuel cell electric vehicles
Fuel cells generate electricity using hydrogen and oxygen and the only emission from the process is water and hot air. They are already used in a wide range of applications, particularly to provide emergency power in databanks, airports and hospitals.
Fuel cell electric vehicles (FCEVs) are more similar to conventional vehicles in many ways than they are to battery-powered electric vehicles. Fuel cells do not need recharging and will instead continue to produce electricity as long as hydrogen is provided. The range and refuelling time of a fuel cell is comparable to that for petrol-based vehicles. Nikola, for example, have a fuel cell powered truck with a range of up to 750 miles and a refuelling time as short as 10 minutes.
Furthermore, the energy density of fuel cells is much higher than that of batteries, so in theory, fuel cells can store much more energy than batteries. For this reason, fuel cells have a future in applications where the disadvantages of batteries are laid bare, such as long-distance road-travel, aviation and shipping.
In practice, fuel cells require heavy cooling systems to function, but this technology is improving. HyPoint, a California-based company, has demonstrated an air-cooled hydrogen fuel cell powertrain that produces 2000W/kg of specific power with an energy density of 1500Wh/kg. This far exceeds the energy density attainable by lithium-ion batteries with a comparable power output. It is hoped that devices such as these could be used to power eVTOLs and small aircraft.
Patent Perspective
Patent filing and publication statistics are often a good indicator of the technologies particular industries and companies are focusing on. The volume of patent filings for batteries remains much larger than for fuel cells, but the latter is on an upward trend.
In recent years, companies with the biggest fuel-cell related patent portfolios are all car manufacturers, with a notable focus on innovators in the Far-East. Japanese companies Toyota, Nissan and Honda are three of the top four patent filers globally. The biggest fuel cell advocate, at least in patent terms, is Toyota, with almost 36 per cent of the total number of filings of the global top eight. South Korean companies Hyundai and Kia also make the top eight.
The governments of Japan and South Korea are both actively encouraging growth and production of FCEVs. Japan wants to have 800,000 FCVs on the road by 2030 and South Korea wants 850,000. The Japanese government set out a strategy back in September 2019 for reducing Japan’s reliance on imported energy, minimising Japan’s environmental footprint and positioning Japan as a fuel cell technology exporter.
Future outlook
Patent filing analysis indicates that Japanese and South Korean companies will play a large role in making FCEVs the future of road transport. But how far will this influence spread? The roll-out of these vehicles may only be local. If other parts of the world do not share the ambition of the Far East and opt to stick with batteries, it will be difficult to attract the large investments needed for the necessary FCEV related infrastructure (refuelling stations, mass hydrogen production) to make FCEVs feasible. That being said, applications in long distance travel, or aviation, may give FCEVs a foothold in these industries due to the advantages fuel cells have over heavy batteries.
Matthew Havron, associate at intellectual property law firm, Reddie & Grose
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