COMBINED INJECTION & RECIRCULATION AT THE ANODE MODULE
What are the main functions of the anode module?
The anode module regulates the hydrogen pressure and concentration and hence ensures optimal hydrogen supply for the fuel cell stack.
As with the oxygen supply at the cathode, the provision of hydrogen at the anode needs to be perfectly adapted to the demand of the stack in order to avoid the “hydrogen starvation phenomenon”, leading to the premature degradation of fuel cell electrodes and components. The processing of hydrogen within a fuel cell based vehicle, from tank storage to metering into the fuel cell stack, requires different levels of hydrogen pressure. An important role therefore plays the function of the low-pressure regulator, which is responsible for metering the exact amount of hydrogen fed into the system. In order to ensure high hydrogen utilization, excess hydrogen that is fed to the fuel cell stack is recycled.
However, due to the recirculation process different issues can occur at the anode: On the one hand, hydrogen can be diluted by nitrogen diffusing through the fuel cell membrane from the cathode side. And on the other hand, water that is produced from the electrochemical reaction at the cathode can also diffuse through the membrane, eventually causing flooding of the electrodes’ porous structure. Both events hamper the efficiency of the fuel cell electricity production.
Therefore, the fuel supply system has not only to maintain a high concentration of hydrogen at the anode, but also needs to ensure the effective removal of inert gases and excess water from the fuel stream.
What are the development goals for the anode module?
The goal is to improve the hydrogen supply by optimizing the H2 pressure regulation and concentration within the fuel cell stack.
The INN-BALANCE project partners will design and realize a combined hydrogen injection and recirculation system, increasing the efficiency of hydrogen distribution within the cell.
The newly developed design of the anode module will comprise an optimally integrated purging system, targeted at the removal of water and nitrogen from the fuel cell stack. A local control system will ensure the optimal regulation of the purge frequency on basis of information gathered by the on-board diagnostic system.