New design and performance evaluation of 1 kW-class reversible solid oxide electrolysis-fuel cell stack using flat-tubular cells

Abstract

A new type of solid oxide cell (SOC) stack using fuel-electrode-supported flat-tubular cells has been developed for reversible fuel cell/electrolysis cell (FC/EC) operation at 700 °C. The flat-tubular cell in which the end of the tube is plugged and the fuel channels inside the cell are connected through the punched holes reaches the easy scale-up and compact stack volume while sustaining its durability benefits. In this configuration, a metallic cassette-type building block is used to securely mount the cell and serves as the current collector. The power generation and hydrogen production performance are investigated using the I–V test. For a 30-layer stack with 100 cm2 of an active area of a single cell, 1 kW of power generation at +43.7 A and 502 L h−1 of H2 production at −40.0 A are achieved in FC and EC modes, respectively. Additionally, it shows high durability against 500 h of steady-state H2 production as well as against 50 FC/EC cyclic operations with a rapid switching rate (2 h cycle−1). Based on these results, we demonstrate its high potential as a promising flat-tubular r-SOC stack for highly efficient power generation and H2 production.