Update on Nexceris' SOFC Stack Technology

Over the past several years, Nexceris has been developing solid oxide fuel cell (SOFC) stacks based on its patented FlexCell planar cell design. The FlexCell is an electrolyte-supported planar SOFC cell design based on a thin electrolyte membrane layer that is mechanically supported by a mesh of electrolyte material, this design enables high performance at targeted operating temperature range of 750 to 850°C. The dense cell periphery provides an optimum sealing surface, and thin anode layers in the FlexCell enable high single-pass fuel utilization without sacrificing performance. Nexceris has demonstrated that SOFC stacks built with this technology are capable of providing targeted power outputs with high single-pass fuel utilization (up to 80 percent), and achieving high efficiencies (45 to 50 percent, LHV basis) when operating on reformed hydrocarbon fuels. More recently Nexceris has leveraged these attributes to establish a stack design which also enables exceptionally high gravimetric power density. Another key capability of Nexceris’ stacks is unprecedented performance and stability with sulfur containing fuels, an enabling attribute for SOFC systems operating on military logistic fuels (such as JP-8). Nexceris’ stacks exhibit stable operation with reformate fuels having as much as 50 ppm H 2 S, with test durations of 500 hours. Ongoing work is aimed at designing high efficiency SOFC systems based on Nexceris’ high power density and sulfur tolerant stack attributes. This work is supported by utilizing an in-house built process model which can accurately predict stack and system performance over a wide array of operating conditions (starting fuel, reforming conditions, fuel flow rate and utilization, cell area, number of cells, etc.). Nexceris currently is demonstrating its SOFC technology at 1-5 kW scale via in-furnace stack testing, ex-furnace hot box testing, and breadboard system testing. This presentation will provide a status update on Nexceris’ SOFC technology.