Abstract: It is an object to shorten current path between an anode and a cathode in a tube type SOFC and thereby to decrease resistance. The tube type fuel cell contains a tube type electrolyte placed between an anode and a cathode, wherein an auxiliary electrode is provided over the entire region of a cell reaction region on at least one of the anode and cathode. The current path is shortened and resistance is decreased, because the anode auxiliary electrode or cathode auxiliary electrode is provided over the entire peripheral surface of the anode or cathode, and the current path in the auxiliary electrode has a greatly increased cross-sectional area.

Abstract: In a solid oxide fuel cell, the nonuniformity of temperature distribution in the axial direction of a solid electrolyte, the decrease in cell performance caused by a decreased effective cell reaction area, and the damage to cell due to thermal stress generated by a temperature difference are restrained. A reforming catalyst is provided in a high-temperature portion on the anode side to cool the high-temperature portion by means of heat absorption of reforming reaction, or a combustion catalyst is provided in a low-temperature portion on the anode side to heat the low-temperature portion by means of heat generation of combustion reaction, or both of the catalysts are provided, by which the occurrence of variations in temperature in a cell reaction region of anode is prevented.

Abstract: In a sodium-sulphur cell, liquid sodium is anodic reactant, sulphur and sodium polysulphide are cathodic reactants and sodium ions are conducted by a solid electrolyte. To increase cell capacity and improve safety, a storage region for cathodic reactants is provided away from said solid electrolyte and containing said cathodic reactants in the form of two contacting layers of immiscible liquids formed by gravitational separation. Liquid sulphur being stored does not contact the solid electrolyte. The sodium may also be stored out of contact with the electrolyte. Capillary-action means for feeding the sodium polysulphide from the two liquid layers to the cathode reaction, and for feeding sodium to the anode reaction are included.