Regenerative Performance of the NASA Symmetrical Solid Oxide Fuel Cell Design

Abstract

The NASA Glenn Research Center is developing both a novel cell design (BSC) and a novel ceramic fabrication technique to produce fuel cells predicted to exceed a specific power density of 1.0 kW/kg. The NASA Glenn cell design has taken a completely different approach among planar designs by removing the metal interconnect and returning to the use of a thin, doped LaCrO 3 interconnect. The cell is structurally symmetrical. Both electrodes support the thin electrolyte and contain micro-channels for gas flow--a geometry referred to as a bi-electrode supported cell or BSC. The cell characteristics have been demonstrated under both SOFC and SOE conditions. Electrolysis tests verify that this cell design operates at very high electrochemical voltage efficiencies (EVE) and high H 2 O conversion percentages, even at the low flow rates predicted for closed loop systems encountered in unmanned aerial vehicle (UAV) applications. For UAVs the volume, weight and the efficiency are critical as they determine the size of the water tank, the solar panel size, and other system requirements. For UAVs, regenerative solid oxide fuel cell stacks (RSOFC) use solar panels during daylight to generate power for electrolysis and then operate in fuel cell mode during the night to power the UAV and electronics. Recent studies, performed by NASA for a more electric commercial aircraft, evaluated SOFCs for auxiliary power units (APUs). System studies were also conducted for regenerative RSOFC systems. One common requirement for aerospace SOFCs and RSOFCs, determined independently in each application study, was the need for high specific power density and volume density, on the order of 1.0 kW/kg and greater than 1.0 kW/L. Until recently the best reported performance for SOFCs was 0.2 kW/kg or less for stacks. NASA Glenn is working to prototype the light weight, low volume BSC design for such high specific power aerospace applications.

Ice‐Templating of Alumina Suspensions: Effect of Supercooling and Crystal Growth During the Initial Freezing Regime

“…Different pore sizes (from 1 to 100 lm), porosity (from 10% to 90%), and pore morphologies can be obtained. Such materials are currently considered for biomedical applications, 3 active substance delivery, 4 acoustic insulation, 5 SOFC, 6,7 or piezoelectric applications. 8 The present study rationalizes our early work about the transient regime.…”

Direct carbon fuel cell: A proposed hybrid design to improve commercialization potential

“…To thin the cells, a hybrid electrode DCFC design was created that incorporated components of a solid oxide fuel cell (SOFC) technology [16] that was developed by NASA. This particular SOFC technology has the unique characteristic of being planar in design but having extremely thin cells compared with other SOFCs.…”

CFD modeling and performance comparison of solid oxide fuel cell and electrolysis cell fueled with syngas

“…Similar designs are implemented to improve the diffusion in the fuel electrode by increasing the porosity, leading to a higher production of H 2 in the EC mode . NASA developed a bielectrode‐supported rSOFC without a channel and interconnector, and thick Ni/Ag and LCC/LGC porous layers were applied to improve the reversible performance and decrease the weight and the high electrochemical voltage efficiencies . Similar studies were performed on other cell design schemes, including channel distribution and cell rib size; however, few studies considered reversible operation with syngas …”