Fuel cells a long way from everyday EVs

August 03, 2020 12:00 AM

Toyota says the fuel cell system on the second-generation Mirai was reworked from top to bottom.

TOKYO — Clean cars that run on the universe's most abundant element and emit nothing but water vapor seem like an ideal solution for tackling the world's energy pinch and climate crisis.

That is why several automakers are racing to develop hydrogen fuel cell technology as a long-term, sustainable path to electrifying transportation. But the key words here are "long term."

Even the most bullish advocates, such as Toyota Motor Corp. and Hyundai Motor Group, concede the technology is still in its infancy and beset with numerous hurdles to mass commercialization. There are the monumental costs of the fuel cell systems, the complexity of building a fueling infrastructure and the question of delivering an affordable hydrogen supply.

Some companies are already dialing back their ambitions as the industry prioritizes the more immediate potential of full-electric vehicles that get their power solely from a battery. Daimler's Mercedes-Benz said in April that it would end development of fuel cell systems for passenger vehicles and turn its fuel cell focus to heavy-duty trucks in a joint venture with Volvo Group. General Motors and Honda are still working together on a next-generation fuel cell system.

Ford Motor Co. announced in 2018 it would wind down its cooperation with Daimler on fuel cells, and BMW has said fuel cells lag EV development by 10 years, even as it readies its own entry. The i Hydrogen Next, based on the X5 midsize crossover, is scheduled for limited-volume production in 2022.

Tech cell advances

Yoshihiko Hamamura is head of the fuel cell electric vehicle program at Toyota.

Q: What areas are engineers focusing on to reduce the cost of hydrogen fuel cells?
A: The first is to reduce the cost of expensive catalysts and other materials. The second is the development cost of the fuel cell stack. The third is the capital expenditure to produce fuel cell systems.

What are some of the technological advances?
The fuel cell has a film that utilizes catalysts, which are expensive. The catalyst consists of small granules, and if you are not able to coat these catalysts uniformly, the efficiency will not go up. However, if you have the technology to evenly or uniformly coat the catalysts, you will be able to promote more chemical reactions with less catalyst.

What are the trends in creating an affordable supply chain?
In Japan, the major technology is producing hydrogen from natural gas. But there are other ways to produce hydrogen. Renewable energy, like wind and solar power, can be used to produce hydrogen through electrolysis. And in China, they are using cow manure to produce hydrogen.

Fuel cell systems are vexingly complex because they bolt on so much extra hardware. They have a high-pressure carbon-fiber-reinforced tank to store the hydrogen. They require a pricey fuel cell stack, which combines the hydrogen with oxygen from the air to generate electricity through a chemical reaction. And they have a battery and electric motor, like full EVs.

Toyota, a fuel cell true believer that cooperates with BMW on the technology, is on track to launch its second-generation Mirai fuel cell car this year, said Yoshihiko Hamamura, head of the company's fuel cell EV program. Toyota is mum on technical details, but the car's chief engineer said last year that the fuel cell system was reworked top to bottom.

One approach to cost cutting is using less expensive materials in the fuel cell catalyst. Toyota's earliest setups used gold-plated stainless steel. Later systems use titanium, but that is also expensive. Another approach is improving the manufacturing process so catalyst granules can more uniformly coat the fuel cells. This will improve their performance, delivering the same output from fewer cells.

Carmakers can also get by with fewer cells if they offset that with a bigger battery.

Meanwhile, Toyota is focusing on ways to speed production of time-intensive steps, such as wrapping hydrogen tanks with carbon fiber. Streamlined manufacturing is another big cost-saver.