In view of the enormous levels of fine particulate and nitrogen oxide pollution in urban areas, more and more hopes are being placed in electric mobility. The availability of mass-produced vehicles powered by alternative drive technologies could help to sustainably improve the quality of the air, as it would then be feasible to impose bans on cars with internal combustion engines for example. This in turn would give a boost to sales of electric vehicles.
Given an appropriate infrastructure, the fact that fuel cell vehicles are easier to refuel and have a greater range makes them superior to battery-powered electric cars. So it comes as no surprise that car manufacturers around the world are making a tremendous effort to promote the commercial use of fuel cell vehicles. The crucial aspect is to reduce the costs. These depend not just on the quantities produced, but even more so on the materials used.
Low-cost materials can cause problems
The heart of a fuel cell vehicle is the PEM fuel cell stack, in which hydrogen and oxygen are converted directly into water, producing electrical energy in the process. Here for example the costs can be reduced either by minimising the amount of platinum used as catalyst in the electrodes or replacing it altogether with alternative materials. It is a basic fact that the electrochemically active cell is susceptible to states occurring outside the operating range. For example: If a hydrogen pipe freezes in winter, cutting off the supply to one of the cells in the system, the intended reaction can no longer take place there. This gives rise to Irreversible corrosion mechanisms inside the cell affecting the carbon-containing components in particular. Consequence: Over the course of time the entire stack will sustain lasting damage and cease to function.
Such unwanted processes can only be avoided by monitoring the fuel cells. The characteristic quantities for fuel cell stack monitoring are the cell voltages. These