Impact of the Powertrain Sizing on Cradle-to-Grave Emissions and Fuel Cell Degradation in a FCV with a Range-Extender Architecture 2022-01-0681

With the rising interest in hydrogen fuel cell vehicles (FCV) to reduce the global warming impact of the automotive sector, the industry and car manufacturers are shifting towards producing H₂-based or electricity-based vehicles. Plug-in passenger FCVs with a range-extender architecture (FCREx), could be a more versatile with a lower total cost of ownership (TCO) alternative to other FCV configurations, given the current H₂ cost.

In this investigation, a validated fuel cell (FC) stack model was integrated into a complete FCREx model to study the potential of this architecture in terms of H₂ consumption and cradle-to-grave GHG and NO_X emissions. First, the FC stack model was calibrated using experimental data. Then, a FC system model including the balance of plant (BoP) was developed and adjusted to the stack specifications. The BoP air management strategy was optimized to ensure maximum performance in steady conditions. From steady-state data, a mean values model of the FC system was developed to reduce the computational cost. Using the fast model, a design space of an FCREx with 600 km of range considering different sizes of FC stack, battery and H₂ tank was generated by evaluating these designs in the WLTC 3b cycle. The results show how the optimum design in terms of H₂ and energy consumption should have the maximum battery capacity and FC stack power while the optimum design to minimize cradle-to-grave GHG-100 and NO_X emissions (blue H₂) corresponds to a powerplant with moderate battery capacity (~30 kWh) and high FC stack maximum power (≥80 kW). This configuration provides promising H₂ and energy consumption levels below 0.8 kg H₂/100 km and close to 30 kWh/100 km, respectively. Finally, 4 diametrically opposed designs were compared in terms of H₂ consumption and degradation rate with an in-house developed degradation model.