Metal hydrides-based hydrogen storage for light mobility applications: performance assessment through 1D numerical modeling

The urgent need to reduce emissions and environmental pollutants requires a substantial diversification of mobility solutions and energy sources. Hydrogen is increasingly recognized as a key energy carrier due to its potential for zero emission applications, high energy density and compatibility with renewable energy sources. However, efficient hydrogen storage is still a critical challenge, as conventional methods such as high-pressure tanks still present high energy intensity and safety and logistical concerns. Metal hydrides, composed of metal powder alloys, have emerged as a promising alternative, offering safe and compact storage at moderate pressures, while posing relevant challenges related to their complex thermal management. This study presents a one-dimensional numerical model to simulate the thermofluid dynamic behavior of metal hydride tanks under realistic load conditions. The model was validated against CFD-based literature data on LaNi₅ alloys and both absorption and desorption tests confirm its predictive capability for temperaturedriven storage dynamics. The model was then applied to a commercial AB₂-type alloy, integrated into a lightduty hydrogen storage tank. A set of simulations was conducted to assess its performance in a fuel cell hybrid electric microcar under a WMTC driving cycle. The analysis highlights the limitations of natural convection in sustaining hydrogen delivery over time and demonstrates the benefits of a passive thermal management strategy based on forced convection using the exhaust airflow from the fuel cell stack. This configuration led to a 75% increase in operating time compared to natural convection, significantly enhancing storage autonomy while maintaining low system complexity. The proposed modeling framework provides a robust tool for supporting the design and integration of metal hydride storage systems in micromobility applications, offering valuable insights into the role of thermal management and seasonal conditions on system performance.