This is the heart of every fuel cell drive system. The stack is the energy transformation unit. It uses atmospheric oxygen and hydrogen from the tank to generate an electric current, which in turn powers the motor.
The fuel cell system
The fuel cell and its ancillary components comprise the fuel cell system, which regulates the operating conditions for the fuel cell so that sufficient hydrogen and oxygen are made available in accordance with the momentary driving condition and are conveyed to the fuel cell at the appropriate pressure. It also helps to dispense with surplus heat via the coolant circuit and to remove water vapor from the vehicle.
The tank system
Gaseous hydrogen at a pressure of up to 700 bar is stored in the hydrogen cylinders of aluminum and carbon fiber. Filling is carried out at hydrogen stations – a procedure not much different from today's filling with gasoline or diesel.
Almost all Daimler fuel cell vehicles produced to date have a battery that both supports the dynamics of the entire drive system and improves overall efficiency factor by recuperating braking energy. The vehicles currently in operation are powered by modern lithium-ion accumulator batteries.
The electric motor
The salient characteristics of an electric motor – a high efficiency factor, and full torque even at very low engine speeds – have a positive effect on a fuel cell vehicle's driving dynamics and overall efficiency factor and dispense with the need for a conventional transmission.