Performance of a hydrogen fuel cell scooter used for combined transport and residential power production

Abstract

A hydrogen fuel cell scooter was tested for the first time to alternatively drive, power electric appliances (Vehicle-to-Load, V2L) and power the grid (Vehicle-to-Grid, V2G). Performance of the scooter is known to rely mainly on the fuel cell stack, and fuel cell degradation depends on the operating conditions. This study aimed to provide insights on how each mode of operation (driving, V2L and V2G) impacts the fuel cell stack performance, as well as the overall system.
Operation in each mode was mimicked by applying typical duty cycles to the hydrogen scooter via an electronic programmable load.
Analysis of the experimental data yielded clear differences between each mode of operation. Principal Component Analysis (PCA) revealed that the voltage of the fuel cell and the battery were most determining in segregating the three modes.
The highest system efficiency was found for V2G usage of the scooter (39.4\% based on higher heating value). The power demand throughout this mode was high, making the fuel cell operate at almost full capacity.
Linear regression analysis was used to determine the fuel cell degradation rate. Severe degradation was measured throughout the experiments, with an overall voltage cell drop of 402 µV/h. Distinguishing the degradation rate per mode revealed V2L operation to cause the largest fuel cell degradation (648 μV/h) and driving the least degradation (205 μV/h). This result was confirmed by comparing the IV curve of the fuel cell stack before and after the experiments: the largest voltage drop occurred at low currents.
Further research on scooter usage in combined modes should include new energy management strategies for V2G and V2L operation, which focus on minimizing fuel cell degradation.