Fuel cell module with stacked electrolyte moments of ceramic honeycomb - forming adjacent cells, thickened at bonding face to ensure good bond even with very thin wall

摘要

Fuel cell module has numerous stacked fuel cell segments, each with numerous adjacent fuel cells formed by a self-supporting honeycomb of ceramic solid electrolyte (I) which conducts 0 ions. The honeycombs form upper and lower open gas ducts, which have porous coatings of electrode material (II). The segments are connected together with gas-tight bonding layers of electroconductive material (III) and connected together electrically in series. The novelty is that the segments (2) have thickened sections (31) near the faces to be bonded to make them at least twice as large as the wall thickness of the electrolyte (3). Pref. the thickened sections consist of (I), (II) or (III) or partly of (II) and partly of (III). The walls of (I) are 0.2-0.4 mm thick and the thickened faces 0.5-1 mm wide. ADVANTAGE - Satisfactory bonding between the segments can be obtd. even if (I) has the very thin walls needed to reduce the resistance and give high energy density. In an example, plane-polished faces of fuel cell segments with electrodes were given 0.05-0.2 mm thick coatings of (III) by dipping to a depth of ca. 1 mm in a slip of (III) powder, e.g. La(Ca,Mg,Sr)CrO3 and/or Ni or Ni/ZrO2 or NiO/ZrO2, and organic additives, e.g. terpineol and ethylcellulose. These were stacked whilst the coating was still moist, and sintered under pressure at max. 1400 deg.C.