Fuel Cells

Such vehicles are typically found in applications that require continuous high power, long driving range, or need for flexibility in operation. Examples could be work machines and long-haul trucks for heavy-goods transport.

When using fuel cell systems in vehicles, they must interact with other vehicle systems and perform well under varying conditions. With increasing industrial efforts to develop fuel cell vehicles, there is therefore an increased need for fuel cell research on several system levels. Fuel economy, thermal management and durability are examples of important knowledge areas.

The fuel economy is of vital importance to achieve competitive operating costs. The fuel economy is determined not only by the energy efficiency of the fuel cell itself, but also by parasitic losses. For example, the compressor that supplies the fuel cell with air typically uses 10 % of the fuel cell output power. Another example is the humidifier, which is needed to maintain the required humidity of the intake air. It causes a pressure drop in the intake system that requires the compressor to work harder, increasing the energy losses.

Like all energy converters, fuel cells have heat losses that must be managed. Due to the typically low operating temperatures, very little excess heat is lost to the exhaust flow. For this reason, almost all heat must be absorbed by the cooling system. The requirements on the radiators increase even further as the heat rejection takes place at low temperatures. Thermal management is therefore an area of increasing importance in fuel cell research.

Performance degradation is another central issue for heavy-duty fuel cell vehicles. Operation under demanding vehicle conditions will cause fuel cells to gradually lose performance over the vehicle life. This means that it is important to develop and investigate control strategies that can minimize this degradation.

The activities of the group include modeling and experiments on full-scale fuel cell vehicle systems. The research is applied rather than fundamental and covers the various system aspects exemplified above.