In this work, the dynamic responses of the on board hydrogen storage system with commercially available metal hydride tanks are investigated based on the database collected from fuel cell electric vehicles operation experiments. A mathematical model considering the heat transfer measured by the temperature control system is developed to analyze the absorption and desorption reaction during operation. As a seal container filled with unknown metal hydride, the practical used hydrogen storage tank is a gray box in the embedded storage system. Without the information about characteristics of material, current operation state and degradation degree, the parameters of the model are uncertain. Particle swarm optimization (PSO) algorithm is applied to search for the optimal parameter set. The simulation results of the hydrogen storage system model using these parameters show great agreements with the real operating data under different temperature conditions; the maximal error is lower than 9%. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.