The PEM fuel cell needs air for its operation and this must be supplied at sufficient pressure to pass through the fuel cell stack. Varying fuel cell power means varying the volume of air passing through the stack. The poor efficiency of existing compressors takes a significant proportion of the fuel cell’s generated power. Increasing the PEM stack pressure to increase power density increases the loss; this generally results in no net power increase and a drop in efficiency because the pressurised exhaust can’t be efficiently expanded.
Our technology in addition to efficient compression also provides efficient expansion. This enables the fuel cell’s power density to be increased by 40% and the cell’s efficiency by 10%.