Bosch to supply fuel-cell components to cellcentric

Stuttgart, Germany – Fuel cells are finding their way onto the roads around the world. For Bosch, the next milestone in this development is a major order for electric air compressors with integrated power electronics. These compressors govern the fuel-cell system’s oxygen supply. Bosch has signed a long-term agreement with cellcentric to supply this high-tech component.

Dr. Uwe Gackstatter

Dr. Uwe Gackstatter

President of the Bosch Powertrain Solutions division

A 50:50 joint venture between Daimler Truck AG and Volvo Group AB, cellcentric is responsible for all activities along the entire value chain. Like Bosch, the joint venture aims to become a leading global manufacturer of fuel-cell systems and thus to help make transportation climate neutral and sustainable by 2050. The air compressor will be part of the cellcentric fuel-cell system that will feature in heavy trucks and stationary applications in the future. Large-scale production is set to begin from around the middle of the decade.

Fuel cells make commercial vehicles climate neutral

In fuel cells, hydrogen reacts with atmospheric oxygen to produce electrical energy as well as water and heat. Running a fuel-cell powertrain on hydrogen that is green – in other words, produced using renewable energy – makes the vehicle climate neutral. As the electric air compressor supplies the required amount of filtered air, it is one of the core components of a fuel-cell system.

Bosch offers the air compressor in two power classes – 20 and 30 kilowatts. The 30-kilowatt class is rated for voltages from 450 to 850 volts, while the 20-kilowatt class is rated for either 250–450 volts or 450–850 volts. The compressor wheel reaches speeds of more than 100,000 rpm. “The combination of a high-speed electric motor with integrated power electronics enables easy system integration at competitive manufacturing costs,” Gackstatter says.

In addition, the silicon carbide semiconductors used in Bosch power electronics make this powerful component particularly efficient. It is features such as these that cellcentric was looking for.

Electric air compressor with integrated power electronicsThe air compressor provides the desired quantity of air in combination with the power electronics. The integration of the power electronics makes the high-voltage wiring between the e-motor and the power electronics redundant. To protect the stack against contamination, the electric air compressor is oil-free. As an integral component of the power electronics, the software facilitates safe operation and a variety of diagnostic functions.

Air path of a fuel cell-electric driveFuel cell control unit

The component is distinguished by its modular structure: The high-speed electric motor with integrated or optionally separate power electronics forms the core, while the variable aerodesign provides the desired flexibility.

Possible aerodesign variants are as follows:

  • Single-stage compressor with turbine. This enables the stack’s exhaust air to be used for energy recovery and increases the compressor’s efficiency.
  • Two-stage compressor that enables a higher pressure ratio.