Significant efforts have been invested in technologies that assist in reducing carbon dioxide emissions and oil from on-road vehicles. Battery electric vehicles, despite a noticeable improvement in the last decade, still have drawbacks that hinder their market diffusion. Therefore, a wide range of hybridized powertrains solutions are available. In this research, a new series hybrid extended range architecture is proposed, in which the generator unit is a hydrogen-powered proton exchange membrane fuel cell. A study is then developed to size the powertrain components and manage the energy flow from a performance and cost point of view. The vehicle model has been realized on MATLAB® and validated through a comparison with a model coming from a 0D software owned by STELLANTIS.