Investigation into the Heat Up Time for Solid Oxide Fuel Cells in Automotive Applications

In this study, the heat up times for an SOFC are investigated looking at temperature gradients and thermal stress to determine if the heat up times are competitive for automotive applications. Different heat up rates are investigated for both single channel and dual channel scenarios. For both scenarios, the set temperature difference heat up methods produce the highest temperature gradients initially, while drastically reducing within 10-15 seconds. The 100 K maximum temperature difference method shows the most promising heat up times of 600 and 273 seconds for single channel and dual channel heating respectively and maximum temperature gradients of 3810 K/cm and 1621 K/cm. For comparison, the 2 K/s ramp rate produced temperature gradients of 1138 K/cm and 133 K/cm with heat up times of 469 and 335 seconds for the single and dual channel studies. The thermal stress model is heavily influenced by residual stress, with the thermal stress being around 550 MPA for the dual channel studies, and 10-20 MPa when residual stress is neglected.