Advancing decarbonisation with fuel cells

Presumably, says Dr. Tore Fischer, he would have ended up studying traditional natural sciences after graduating from high school, perhaps physics or mathematics. However, the Hamburg native grew up in Hanover, where only two subjects interested him enough to study them after high school: mechanical engineering or gravitational physics. The latter seemed too abstract to him, so he opted for mechanical engineering with a specialisation in automotive engineering instead.

Text: Mathias Heerwagen | Photos: Stefan Bausewein,  FFCC

His fascination with hydrogen developed slowly. Even though he was not studying it, he attended the fuel cell lecture twice out of interest during his studies. He would actually have become a »Prime Mover«. However, a change in professorship at the university prompted him to reorient himself. After all, thermal turbomachinery also sounded interesting. »It was a similar topic, but with more speed and less imbalance,« he laughs. By the sixth semester at the latest, he knew he was heading in the direction of turbomachinery. Fischer worked on large radial compressors, moved into numerical analysis, and ended up with exhaust gas turbochargers. During his PhD, he came into contact with fuel cell technology for the first time, working on a radial fan for fuel cells as part of a public research project. From then on, »the hydrogen topic has always been there.«

After five years of research, the engineer left the university in 2017. »I had set myself this timeline and then wanted to do something practical. However, it wasn't the best time, as there were only two suitable positions in the turbocharger field at the time, one in Mexico and one in China.« While certainly interesting, this was not what Fischer had in mind. He used his contacts and broadened his circle of interests. At the time, fuel cell technology was on the rise, and in 2018, FISCHER Spindle Group AG in Herzogenbuchsee, Switzerland, reintegrated its previously outsourced compressor division – a perfect fit. In 2020, the division was spun off as FISCHER Fuel Cell Compressor AG (FFCC), and Fischer completed his doctorate in the same year. Now, with a team of three, he is responsible for making the current generation of compressors more robust for large-scale production. At that time, there were collaborations with VW and the Canadian fuel cell pioneer Ballard Power Systems, for example. Fischer is tasked with tackling the classic issues of improving quality and reducing costs. He took responsibility for the test field two years ago and became head of pre-development.

In his day-to-day work, Tore Fischer frequently offers guidance to his team of eleven young people on projects. »They’re eager to be innovative, so it’s important to channel their energy in the right direction,« says the engineer. As well as decentralised energy generation, where fuel cells excel in terms of power density, Fischer believes that trucks, buses, boats and small ferries are the ideal areas of application. »That will clearly be the market when we phase out combustion engines. I don't foresee fuel cells being used in passenger cars in the next few years, as too much money has been invested in battery development and production.«

But what do turbomachines have to do with fuel cells? »Every fuel cell needs compressors to generate power efficiently. The greater the number of oxygen molecules per square centimetre of cell surface area, the greater the energy generation – higher boost pressure means greater power,« Fischer explains. For fuel cells with a stack output of between 50 and 300 kW in stationary applications, the boost pressure is between 1.5 and 2 bar. Up to 2.7 bar is applied when the fuel cell generates energy in vehicles.

Fischer faced several challenges during development, not all of which were technical in nature. For example, the air used in the fuel cell's chemical reaction must be completely clean and free of oil. »We need oil-free bearings for the compressor shaft, but none of the ›old‹ technologies work for this,« says Fischer. Foil bearings could be one solution. However, FFCC has developed an unusual air bearing for the market that does not require foil, replacing oil with air, and achieving a bearing clearance in the range of hundredths rather than tenths of a millimetre. These particularly low-loss bearings can only be manufactured with a great deal of technical expertise and precision machinery. And who invented them? In this case, it wasn't the Swiss. The development dates back to a NASA patent from the 1960s. Fuel cell exhaust gas is also »unsuitable for a turbomachine« because the water vapour has a low temperature and high humidity and liquid water content. Accordingly, the electric motors and air bearings of the compressors must be well sealed.

In addition to the technical challenges, Tore Fischer occasionally struggles with the mentality in this country. »While the Japanese simply develop a fuel cell car, launch it on the market and gather field experience, in Europe a system is developed, ten prototypes are built for a fleet trial and then the next system is immediately developed, because that is much more exciting than bringing one to series production,« he says, describing a problem he occasionally observes on the OEM side. 

From a technological perspective, he also disapproves of certain political decisions. When funds are channelled into armaments rather than the energy transition, companies feel the impact, and the least established technologies are scaled back. VW discontinued fuel cell development years ago and Audi and Bosch are scaling back their activities, but FISCHER Fuel Cell Compressor AG is experiencing growth. The company's key strength lies in its almost complete in-house development and production capabilities, covering areas such as aerodynamics, bearings, cooling and electric motors. However, the engines are produced externally, representing virtually the only component not developed in-house. This breadth and depth of production is one of the reasons for FVV membership.

»The FVV provides insight into pre-competitive research in many areas, including combustion engines. Topics covered include ammonia and hydrogen combustion, as well as exhaust gas aftertreatment. This enables us to stay up to date,« says Fischer. This is important for understanding the market. »I fought for five years to get us, as a Swiss company, to become a member of the FVV. The network of peers is attractive, and we make intensive use of the knowledge in THEMIS because it helps us to progress,« explains Fischer, who is currently preparing his own project and is about to submit his application. He had to do some internal lobbying to become a member, as the research association is hardly known in Switzerland. However, he believes that membership is incredibly valuable for SMEs with small research budgets and that it would be useful to communicate the benefits more effectively in order to attract more SMEs. After all, collective research also helps to reduce costs, which is an important point because: »The focus is currently on costs, and these fall sharply as production volumes increase. You can see this with electric cars: thanks to subsidies, the same model now costs roughly the same as the combustion engine version. And that was a development that took about ten years.« This demonstrates the potential of a technology that is politically desired, promoted, and put into series production.

Fischer ventures a glimpse into the future. Provided that politicians set the course in the right direction, he is convinced that fuel cell technology will be successful. »Except for aeroplanes and large ships, I believe it is the energy source we need in terms of renewables, grid stability, and decarbonising road transport.« Technically, we are already close to what is feasible, but Fischer still sees potential for improvement in terms of power density. For example, the use of a turbine on the compressor can increase shaft power by up to 40 per cent, thus enabling significantly larger fuel cell systems to be ›ventilated‹ in the same installation space.

Tore Fischer's decision to keep his combustion engine car is proof that he is planning for the long term and sustainability. The eight-year-old car is expected to last another seven years, after which Fischer could well consider buying a fuel cell car if the refuelling infrastructure is suitable and the price is reasonable. He knows that the costs have to come down. //