The invention provides a
solid oxide fuel
cell device and a fuel
cell system incorporating a plurality of the fuel devices, each device including an elongate substrate the length of which is the greatest dimension such that the elongate substrate has a coefficient of
thermal expansion having only one dominant axis that is coextensive with the length. A
reaction zone is provided along a first portion of the length for heating to an operating
reaction temperature, and at least one
cold zone is provided along a second portion of the length that remains at a low temperature below the operating
reaction temperature when the
reaction zone is heated. A plurality of fuel passages and oxidizer passages are provided in the elongate substrate extending from the at least one cool zone to the
reaction zone, each fuel passage having an associated
anode in the reaction zone, and each oxidizer passage having an associated
cathode in the reaction zone positioned in opposing relation to a respective one of the associated anodes. An
electrolyte is disposed between each of the opposing anodes and cathodes in the reaction zone. The
system further includes the devices positioned with their first portions in a
hot zone chamber and their cold zones extending outside the
hot zone chamber. A heat source is coupled to the
hot zone chamber to heat the reaction zones to the operating
reaction temperature. A
fuel supply is coupled outside the hot zone chamber to the at least one cold zones in fluid communication with the fuel passages for supplying a fuel flow into the fuel passages.