Solid oxide electrolytic system

Abstract

A solid oxide fuel cell, solid oxide electrolyzer, and associated interconnect structure is disclosed for use in solid oxide electrolytic devices that use chrome-containing components, such as solid oxide fuel cells and solid oxide oxygen-generators. The invention provides a reliable and durable interconnect for both structural and electrical components of such devices. In general, the interconnect structure relies on a dual-layer, high-temperature seal which provides an effective diffusion barrier for both chrome and oxygen. As a result of the described interconnect, corrosion or loss in electrical conductivity in such solid oxide electrolytic devices is avoided. Also, a novel structure for such solid oxide electrolytic devices is disclosed, which provides an economical and high-integrity structure that utilizes the disclosed interconnect structure. A result of the present invention is that thin film solid oxide fuel cells and solid oxide oxygen generators may be fabricated using only metal alloys as bulk components.

1 . An annular SOFC system, comprising:
 a.) a plurality of integral electrolyte/electrode assemblies, the electrolytic assemblies each comprising a substantially metallic structural component, the structural component having a thin planar aspect with a first side and a second side, the structural component having an active region providing an electrolytic function, the active region forming a circular array having an axis of rotational symmetry, the active region forming a substantially annular pattern, the annular pattern substantially concentric to the central axis;   b.) central gas manifold means disposed at the central axis;   c.) peripheral gas manifold means substantially concentric to the central manifold means, the peripheral manifold means peripheral to the active region and disposed at regular intervals about the planar element for providing gas flow between the central manifold means and the peripheral manifold means;   d.) a plurality of interconnect structures interleaving the electrolytic assemblies.   
     
     
         2 . The annular SOFC system of  claim 1 , wherein additional features are provided for guiding a gas in the fuel cell, the features guiding the gas in radial directions so that average flow of a gas at one side of the electrolyte is provided in a substantially radial direction. 
     
     
         3 . The annular SOFC system of  claim 1 , wherein the electrolyte is less than 10 microns thick, the electrolyte formed by vapor deposition means. 
     
     
         4 . The annular SOFC system of  claim 1 , wherein the electrolyte/electrode assemblies comprise a thin planar substrate having a predetermined pattern of recessed features. 
     
     
         5 . The annular SOFC system of  claim 1 , wherein a porous electrode layer is formed on either side of the electrode/electrolyte assembly. 
     
     
         6 . The annular SOFC system of  claim 1 , wherein the metallic structural component is a 400 series stainless steel. 
     
     
         7 . A solid-oxide electrolyzer for separating oxygen from an oxygen-bearing gas, comprising:
 a.) a thin planar support structure formed from a substantially non-porous material, the support structure having a first side and a second side, the support structure patterned with a plurality of hole structures, the hole structures each having a hole interior surface extending between the first side and the second side, the hole interior surface defining an opening in the support structure;   b.) an electrolyte layer disposed within each through-hole structure, the electrolyte layer having a first layer side, the electrolyte layer having a first region wherein the first layer side is attached to the interior surface, the electrolytic layer having a second region wherein the first layer side is not attached to the interior surface, the second region spanning the opening.   
     
     
         8 . The solid oxide electrolyzer of  claim 7 , wherein the planar support structure comprises a metal structure that is coated with at least one metal oxide layer, the metal oxide layer providing electrical continuity for operation of the device. 
     
     
         9 . The solid oxide electrolyzer of  claim 7 , wherein the electrolyte is a thin film formed by a vapor deposition method. 
     
     
         10 . A metallic interconnect structure in a solid oxide electrolytic system, comprising:
 a.) a substrate, the substrate comprising a substantially non-porous metal, the substrate having a multitude of predetermined features formed therein, the features disposed for providing flow of gases therein;   b.) a first layer formed over the substrate, the first layer comprising a metal oxide, the metal oxide an electrically conductive metal oxide, the first layer substantially non-porous; and,   c.) a second layer formed over the first layer, the second layer a metal, the metal substantially resistant to oxidation during operation of the electrolytic device.   
     
     
         11 . The solid oxide electrolytic device of  claim 1 , wherein the electrolytic function is that of a gas separation device. 
     
     
         12 . The solid oxide electrolytic device of  claim 1 , wherein the electrolytic function is that of a solid oxide fuel cell. 
     
     
         13 . The solid oxide electrolytic device of  claim 1 , wherein the predetermined features comprise through-hole structures, the through-hole structures containing an electrolyte layer that spans the space formed by the through-hole structure, thereby forming an electrode/electrolyte assembly. 
     
     
         14 . The solid oxide electrolytic device of  claim 1 , wherein the metal oxide possesses a perovskite crystalline structure.