Slurry-based chemical hydrogen storage systems for automotive fuel cell applications

In this paper, the system designs for hydrogen storage using chemical hydrogen materials in an 80-kWe fuel cell, light-duty vehicle are described. Ammonia borane and alane are used for these designs to represent the general classes of exothermic and endothermic materials. The designs are then compared to the USDRIVE/DOE-developed set of system-level targets for onboard storage. While most DOE targets are predicted to be achieved based on the modeling, the system gravimetric and volumetric densities were more challenging and became the focus of this work. The resulting system evaluation determined that the slurry accounts for the majority of the system mass. Only modest reductions in the system mass can be expected with improvements in the balance-of-plant components. Most of the gravimetric improvements will require developing materials with higher inherent storage capacity or by increasing the solids loading of the chemical hydrogen storage material in the slurry.