GM debuts fourth-generation Hydrogen fuel cell car

Electric turbo compressor provides air to fuel cells

The heart of the HydroGen4 is its fuel cell stack. Fuel cells convert chemical energy into electrical energy without combustion. Via an electro-chemical reaction, they combine hydrogen and oxygen to form water, and produce electricity at the same time.

The electro-chemical process in a fuel cell works as follows: Hydrogen on the anode catalyst splits into protons and electrons. The positively-charged protons pass through the membrane to the cathode, while the negatively-charged electrons travel in an external circuit, producing electricity on the way. On the cathode catalyst, oxygen reacts with the electrons and protons to form water. A stack connecting a large number of individual cells can thus produce enough power to drive an electric motor.

Unlike its predecessor, the individual cells of the new stack are positioned horizontally – as opposed to vertically – for packaging reasons, i.e. for optimal distribution of the individual components in the vehicle. The gas supply to the stack is also different in the HydroGen4 compared to the HydroGen3: instead of a screw-type compressor at the cathode, an electric turbo compressor provides the fuel cells with air. This increases efficiency and acoustics.