SOFC technology for heavy-duty vehicle propulsion

Solid oxide fuel cell (SOFC) systems can be integrated into heavy-duty vehicle (HDV) powertrains for applications where the vehicles are regularly and intensively used, such as commercial vehicles for long-haul road freight, as well as in buses, taxis, ships, etc. In such applications, cold-start of the fuel cell system is rare and current start-up times for the SOFC system are acceptable.

Using SOFCs for commercial vehicle applications allows for compatibility with the current trends towards LNG in freight transport. Given that natural gas can be replaced by synthetic natural gas (SNG) with carbon dioxide from biomass sources, a fully decarbonised and carbon neutral transport concept is achieved. The advantage over a pure low-temperature/hydrogen system is the higher efficiency of the fuel cell system, higher volumetric energy density of the fuel and the benefits of the high temperature off-heat. The phasing-in of such a system would occur without any disruption since it would use the current natural gas (methane) infrastructure. The application on commercial vehicles also includes refrigerated goods transport where the off-heat available from the SOFC system can power a vapour absorption refrigeration system.

This paper presents a zero-dimensional (0D) dynamic model of an SOFC stack with direct internal reforming (DIR) of methane, suitable for the integration into a vehicle powertrain. The area and number of cells define the stack size to meet the vehicle load requirements. The model uses an area specific resistance (ASR) approach to estimate polarisation losses and defines a lumped solid heat capacity to determine dynamic thermal response to a step change in load. The model shows good agreement with experimental data in the literature.