Patent ID: 7226691

Claim:
A unit cell for a solid oxide fuel cell, comprising: a substrate; a battery element formed on the substrate and provided with an electrode layer and an electrolyte layer; a high porosity layer disposed in the substrate; and a low porosity layer including a first low porosity layer, disposed in the substrate with material to be included in the substrate, and a second low porosity layer, disposed in the electrode layer with material to be included in the electrode layer, and the second low porosity layer being formed and laminated on the first low porosity layer, with the electrolyte layer being formed and laminated on the second low porosity layer, wherein a porosity of the first low porosity layer is lower than that of the high porosity layer and equal to or higher than that of the second low porosity layer, with value ranges of a pore size, a thickness and a surface roughness Ra of the first low porosity layer being the same as those of the second low porosity layer.