A fuel cell device with a rectangular solid ceramic substrate extending in length between first and second end surfaces where thermal expansion occurs primarily along the length. An active structure internal to the exterior surface extends along only a first portion of the length and has an anode, cathode and electrolyte therebetween. The first portion is heated to generate a fuel cell reaction. A remaining portion of the length is a non-heated, non-active section lacking opposing anode and cathode where heat dissipates along the remaining portion away from the first portion. A second portion of the length in the remaining portion is distanced away from the first portion such that its exterior surface is at low temperature when the first portion is heated. The anode and cathode have electrical pathways extending from the internal active structure to the exterior surface in the second portion for electrical connection at low temperature.