Evaluation of Electrical Load Following Capability of Fuel Cell System Fueled by High-Purity Hydrogen

摘要

This paper describes the electrical response in the load change in a fuel cell system fueled by high-purity hydrogen. The purpose of this study is to use the fuel cell system to make up for the unstable electrical output of a photovoltaic system utilized as a renewable energy source. As an alternative method instead of a secondary battery, the fuel cell system, which is able to continuously generate power as long as fuel is supplied, is expected to provide better power with higher reliability and stability. To evaluate the load-following capability of a polymer electrolyte fuel cell (PEFC) system, an experimental setup was constructed with a 200-W PEFC stack (number of cells: 20; cell area: 20 cm~2), which was supplied with hydrogen from a compressed hydrogen cylinder and a metal hydride canister. We measured the transient phenomena in the current and cell voltage when the PEFC stack was given step-up current loads that changed in the range of 0 to 300 mA/cm~2. It was found that PEFC systems with both hydrogen supply sources are able to respond with a time constant of 6.6 to 11.6μs in the presence of an adequate oxygen supply and at a load below the PEFC rated power.