Real-Time Capable Transient H2 Partial Pressure Model for Proton Exchange Membrane Fuel Cell Systems

Fuel cell electric vehicles hold a significant promise for reducing the carbon footprint in the automotive sector by leveraging H 2 as a clean fuel source. Maintaining a consistent H 2 supply to the fuel cell system is vital. N 2 crossover can lead to an inert gas built-up on the H 2 supply side, adversely affecting fuel cell performance and durability. Through purging, gases are released, and a N 2 built-up in the H 2 supply system can be prevented, yet this also leads to fuel loss. This fuel loss can be minimized by keeping an optimal N 2 molar fraction. We developed a dynamic model for effectively designing, controlling, and diagnosing fuel cell systems by predicting the N 2 molar fraction in the H 2 supply. This model considers factors such as N 2 distribution throughout the fuel cell stack, N 2 crossover, and the purge process. The model is simplified to a differential equation of first order and solved using the explicit Euler method at a typical automotive time step of 0.01s. The proposed model is validated by a H 2 measurement in a fuel cell system with passive recirculation.