Solid-state technology is being tipped as the best way to get automotive powertrains switched to hydrogen power.
Automotive supplier Denso claims it is on the cusp of cracking the challenges to mass adoption of hydrogen fuel cell-powered vehicles using locally produced and consumed “green” hydrogen.
The company is staking its future powertrain development plans on solid oxide electrolysis cells (SOECs) to produce inexpensive green hydrogen to power its solid oxide fuel cells (SOFCs). The technologies are under development at the company’s Hirose plant, at Toyota City and Nishio City plant, both located in the heart of Japan’s Aichi Prefecture.
Denso started its fuel cell pilot project in Nishio in May 2023 to assess and evaluate the operations of an energy management system featuring its new fuel cells working in tandem with other energy sources, including solar panels and storage batteries.
The company points out that automakers and energy providers currently are using several types of fuel cells. For example, transport-grade polymer electrolyte membrane fuel cells (PEMFCs) use electrolytes made from resin membranes. These membranes react at about 100°C (212° F), allowing for a short start-up time.
However, Denso’s SOFCs use ceramic-based electrolytes. Ceramic membranes react at about 700°C (1,292° F). While they require a longer start-up time, they are also able to convert fuel into energy more efficiently using high-temperature waste heat. These could have advantages in applications where uninterrupted operations are required.
In a company statement, Masahiro Ishimaru, currently in charge of the project in the passenger vehicle thermal system business unit, explains: “We developed a system that controls the amount of energy generated and stored in SOFCs based on forecast data for the weather and factory energy requirements. This will help us build a more efficient and stable energy supply while ensuring we cut CO₂ emissions.”
He also says Denso’s technology can also be used in the production of “gray” hydrogen from fossil fuel sources.
Ishimaru adds: “While hydrogen is growing in prominence as a viable energy source, we’re still in a transition period. There are still cases in which it can’t fully replace fossil fuels, mostly because of cost factors and convenience. Having said that, if we can leverage SOFCs to generate hydrogen through fuels like city gas, we can expect to see a significant cut in CO₂ emissions in terms of power generation and a big contribution to decarbonization efforts over the long term.”