Energy recovery and efficiency improvement method of proton exchange membrane fuel cell system by applying the expander in plateau environment

The compressor can improve the performance of proton exchange membrane fuel cell (PEMFC) system, but excessive parasitic power can actually have a counterproductive effect. PEMFC system also faces the issue of plateau environmental adaptability. This paper experimentally verifies the energy recovery effect of the expander and explores the system performance in plateau environment. In plain environment, with a rated stack power of 162.2 kW, the application of the expander decreases the air compressor power from 18.7 kW to 13.2 kW, and increases the system efficiency from 44.5 % to 46.5 %. Based on simulation model, further research is conducted on plateau environment. PEMFC system can operate under rated conditions below an altitude of 3000 m. At an altitude of 0–3000 m, the compressor power increases from 18.1 kW to 24.9 kW, and the system efficiency reduces from 44.8 % to 42.5 %. By applying the expander, the air compressor power reduces to 16.8 kW, and system efficiency increases to 45.1 %. The working boundary of the compressor limits the operating load and altitude of PEMFC system. The expander can achieve better energy recovery effect in high current density and plateau environment. In future, the expander will be an indispensable part of high-power PEMFC system. •The improvement of PEMFC system efficiency by the expander is investigated.•System efficiency is improved by reducing air compressor parasitic power.•The improvement of load efficiency contributes to voltage efficiency.•The compressor working boundary limits PEMFC system in plateau environment.•The expander has a significant effect in high load and plateau environment.